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Thin Film Coating Blog

Browse our blog to learn more about thin film and conformal coating processes, material, and application. Find out more about HZO and how our solutions can help your market.

Polymer Glass Transition Temperature - Material Properties, Impact

Polymer glass transition temperature (Tg) refers to the temperature at which an amorphous polymer transitions from a glassy, rigid state to a rubbery, flexible state...

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What is Coefficient of Linear Expansion? Formula, Units & More

Temperature affects the behavior of materials, causing them to expand or contract. However, not all materials respond to temperature variations in the same way. Some materials,..

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Diagram of thermal conductivity

What is Thermal Conductivity? Explanation, Measurement, Uses

Thermal conductivity is a fundamental concept in heat transfer and is crucial in multiple industries and scientific disciplines. It refers to the ability of a material to conduct..

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Index of refraction illustrated through glass

What is the Index of Refraction? Measurement, Definition & More

Understanding how light travels through different mediums is essential in optics. One invaluable optical property is the index of refraction. This measurement quantifies how much..

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testing for tensile strength at yield

Tensile Strength at Yield - Testing, Standards, Specs, Material

The ability to accurately predict the behavior of coating materials under tension is crucial in ensuring the integrity and reliability of electronic components. This includes..

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Elongation at Break - Definition, Testing, Material Selection

Elongation at break is a key mechanical property that measures the deformation capacity of a material before it eventually snaps or breaks, providing insights into the material's..

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Diagram of Young's Modulus

Young's Modulus of Polymers - Measurement, Calculation

Young's Modulus is an important property, allowing engineers to select coating materials based on their desired stiffness. Understanding and manipulating the elastic Modulus of..

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Water Vapor Transmission Rate - Standards, Testing, Material

In the world of electronics, moisture control is of utmost importance. High water vapor transmission rate (WVTR) can pose significant risks to sensitive electronic devices. When..

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transparent polymer coating on a piece of glass

Transparent Polymers - Applications, Material Selection

Transparent polymers offer optical clarity and the ability to transmit light. With various applications across various industries, these polymers have gained popularity for their..

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Biocompatible Coatings - Coating Techniques, Applications, More

Biocompatible coatings seamlessly integrate with the human body, offering benefits through their ability to promote healing and prevent adverse reactions. They can improve patient..

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Dissipation Factor - Definition, Measurement, Variables

Dielectric materials are crucial in various industries and applications, serving as insulators, substrates, or capacitors. One important characteristic often evaluated in..

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Volume Resistivity - Definition, Measurement, Product Design

Whether designing circuit boards or protecting electrical components, knowledge of the volume resistivity of coating materials plays a pivotal role in creating efficient and..

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UL94 Coating Material - Testing Method, Material Selection

Fire safety compliance is an indispensable aspect across various industries. One crucial benchmark in fire safety compliance is UL94, a widely recognized standard for flammability..

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Yield Elongation of a material

Elongation Yield: Overview, Unit of Measure, Data and Testing

Elongation yield refers to the maximum amount of deformation a material can undergo before it experiences a permanent change in shape or size. This property is fundamental in..

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ADAS Design and Validation for the Real World - Automotive Coatings

Advanced driver assistance systems (ADAS) continue to expand in features and functionalities. Standard offerings may include adaptive cruise control, park assist, blind-spot..

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Parylene Conformal Coatings - Parylene Conformality Explained

Parylene (p-polyxylylene) conformal coatings are unique due to their capacity to be polymerized and deposited by the chemical vapor deposition (CVD) method onto surfaces near room..

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Parylene Chemical Resistance Properties - Overview

Choosing a conformal coating can be a complex decision that entails understanding the environment your electronic products will be operating in and taking stock of the threats to..

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Parylene Biocompatibility Properties

As a long-proven biocompatible material, Parylene conforms to ISO-10993 and is USP Class VI implantable material. Its properties make it ideal for biological and medical..

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Parylene N Properties Explained Datasheet PDF Download

Parylene is the generic name for poly-para-xylylenes. These conformal coatings come in several varieties, including Parylene C, Parylene F (VT-4), and Parylene N. Parylene..

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Engineer Looking at Coating With Equipment

Parylene C Datasheet (PDF Download) - Properties Explained

Parylene conformal coatings come in various types, including Parylene C, Parylene N, and Parylene F (VT-4), with decades of trusted performance in critical industries and..

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How to Choose a Nanocoating Material

As engineers, it is our job to bring products to life and ensure they operate as expected until the end of the product life cycle. Therefore, a large part of our job is to prevent..

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NEMA vs IP Ratings Explained

Once upon a time, computers only sat perched on desktops, but that is no longer the case. Deployed in harsh industrial, medical, automotive, and consumer household environments,..

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Conformal Coating Thermal Conductivity - Prevent Overheating

Design engineers have more to worry about these days than ever before. The demand for smaller electronic devices with more capabilities is exponentially growing, causing..

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IoT - Coating Consistency is Key

IoT sensors aggregate and send data to IoT dashboards, simplifying critical, complex decisions quickly. One key area where this is particularly true is the utilization of sensor..

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Example of Parylene optical properties

Parylene Optical Properties - UV Light Interactions, Refractive Index

With Parylene, you always have a clear and accurate view due to its optical properties. Although the Parylene deposition process begins with white to off-white dimer powder, the..

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Parylene Temperature Range - Extreme Hot & Cold Temperatures

Do you need product protection that can withstand temperature extremes? Parylene may be a good option if you utilize the correct type. Learn more about why Parylene is used..

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Parylene Coating Thickness – How Much is Enough?

If you are considering a Parylene coating for your printed circuit board assembly, you may wonder what thickness you should use. You may have surmised that the more coating, the..

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Polyurethane Conformal Coatings - Benefits & Applications

Conformal coatings are polymeric materials applied to a PCB to improve device reliability. These films protect electronics from environmental threats, including humidity, liquids,..

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Coating engineer inspecting parylene film on pcb

Parylene - Different Types & Properties Explained

Parylene is a chemical compound applied to substrates using chemical vapor deposition (CVD). Because Parylene coating deposits onto the surface molecule by molecule, it forms a..

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Epoxy Conformal Coating Evaluation Guide

Conformal coatings are polymeric materials applied to substrates. These films are a barrier to protect electronics from environmental hazards, such as corrosion, humidity,..

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How Small is a Nanometer? Nanometers Explained

We live in a growing world. Every day, cars are getting bigger, buildings are getting taller, phones are getting larger, and Americans are getting wider (I can say that; I’m an..

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Polymer Glass Transition Temperature - Material Properties, Impact

September 21, 2023 / by Mallory McGuinness-Hickey posted in Protection Capabilities, Coating Properties

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Polymer glass transition temperature (Tg) refers to the temperature at which an amorphous polymer transitions from a glassy, rigid state to a rubbery, flexible state. Understanding the polymer glass transition temperature is crucial for various industries, including engineering and manufacturing. The Tg provides valuable insights into a polymer's behavior, such as its processing, mechanical, thermal, and overall performance characteristics.

The polymer's structure, molecular weight, chemical composition, and branching influence the glass transition temperature. The Tg affects properties like stiffness, impact resistance, thermal stability, and transparency. Design engineers can optimize material selection, processing conditions, and performance requirements by understanding how the Tg relates to polymer structure.

Basics of Glass Transition

The glass transition is a phenomenon that occurs in amorphous polymers where the material changes from a rigid and brittle state to a softer and more flexible state when certain temperature conditions are met.

Several factors can affect the glass transition temperature (Tg) of polymers:

  • Molecular weight and chain length: Polymers with higher molecular weights and longer chain lengths tend to have higher Tg values.
  • Chemical structure and composition: Different chemical structures and compositions can result in variations in Tg values.
  • Presence of plasticizers or additives: Plasticizers and additives can lower the Tg of polymers, making them more flexible and less brittle.
  • Crystallinity or amorphous nature of the polymer: Amorphous polymers generally have lower Tg values than crystalline polymers.

Influence of Glass Transition Temperature on Polymer Properties

A polymer's glass transition temperature (Tg) plays a crucial role in determining its properties and performance. This temperature marks the transition from the glassy state to the rubbery state, where the polymer undergoes significant changes in its physical and mechanical behavior.

Impact on mechanical properties

The glass transition temperature has a profound effect on various mechanical properties of polymers, such as:

  • Tensile strength: The Tg of a polymer can influence its tensile strength. Polymers with a higher Tg tend to have higher tensile strength, as the increased molecular mobility at elevated temperatures allows for better alignment and bonding.
  • Elastic modulus: The Tg also affects the elastic modulus, which refers to a material's ability to resist deformation. Polymers with a higher Tg typically exhibit a higher elastic modulus, indicating greater stiffness and rigidity.
  • Impact resistance: The Tg can impact the impact resistance of polymers. As the Tg increases, the polymer becomes more brittle and prone to fracture upon impact. On the other hand, polymers with lower Tg values exhibit better impact resistance and toughness.

Effect on thermal behavior

The glass transition temperature has significant implications for the thermal behavior of polymers:

  • Melting temperature and thermal conductivity: The Tg influences the melting temperature of a polymer. Polymers with higher Tg values generally have higher melting temperatures. Additionally, a higher Tg can result in lower thermal conductivity, which affects the material's ability to transfer heat.
  • Heat resistance and aging: The Tg indicates a polymer's heat resistance. Polymers with high Tg values exhibit better heat resistance and are less prone to degradation at elevated temperatures. Furthermore, understanding the Tg is crucial for predicting the long-term aging behavior of a polymer in various environmental conditions.

Temperature-Dependent Polymer Properties

Temperature plays a crucial role in determining the properties of polymers. As the temperature changes, various characteristics of polymers undergo significant transformations. Understanding the temperature-dependent behavior of polymers is essential for a wide range of applications, from material selection to manufacturing processes.

Changes in Polymer Properties with Temperature Variations

When exposed to different temperatures, polymers exhibit distinct alterations in their properties. These variations include changes in mechanical strength, electrical conductivity, chemical resistance, and dimensional stability. For example, as the temperature rises, the mechanical strength of a polymer tends to decrease due to increased molecular motion.

Relationship Between Glass Transition Temperature and Other Temperature-Dependent Properties

Glass transition temperature has a relationship with other temperature-dependent properties, including:

  • Specific heat capacity: The glass transition temperature of a polymer is closely related to its specific heat capacity, which is the amount of heat required to raise the temperature of a unit mass of the material by a certain degree. Understanding this relationship is essential for predicting polymers' heat absorption and release capabilities at different temperatures.
  • Coefficient of thermal expansion: The coefficient of thermal expansion measures the extent to which a material expands or contracts when subjected to temperature changes. The glass transition temperature considerably influences the coefficient of thermal expansion of polymers. Higher glass transition temperatures generally result in lower coefficients, indicating reduced dimensional change with temperature.
  • Viscosity and flow behavior: As the temperature varies, polymers experience viscosity and flow behavior changes. Polymers act as rigid solids with high viscosity at temperatures below the glass transition temperature. However, as the temperature surpasses the glass transition temperature, polymers transition into a more flexible state, exhibiting lower viscosity and increased flow characteristics.

Measurement and Determination of Values

Obtaining accurate glass transition temperature data is essential. Several experimental techniques may be employed for measurement, including:

  • Differential Scanning Calorimetry (DSC): DSC is a widely used technique that measures the heat transfer in a sample as it goes through a glass transition. It provides information about the glass transition temperature and the enthalpy of transition.
  • Dynamic Mechanical Analysis (DMA): DMA measures the mechanical properties of a sample as a function of temperature or frequency. It can provide information about the glass transition temperature by observing changes in the sample's modulus, damping, and storage modulus.
  • Thermomechanical Analysis (TMA): TMA measures the dimensional changes of a sample as a function of temperature or time. It can determine the glass transition temperature by monitoring changes in the sample's dimensions.
  • Fourier Transform Infrared Spectroscopy (FTIR): FTIR measures a sample's absorption of infrared light. Analyzing the changes in the infrared spectra of the sample as a function of temperature can determine the glass transition temperature.

Factors influencing the accuracy and repeatability of glass transition temperature measurements

Several factors influence the accuracy and repeatability of glass transition temperature measurements, such as:

  • Heating and cooling rates: The rate at which the sample is heated or cooled can affect the observed glass transition temperature. Different heating and cooling rates can lead to variations in the measured value.
  • Sample preparation and handling: How the sample is prepared and handled before the measurement can also impact the glass transition temperature. Contamination or improper handling can introduce errors.
  • Physical state of the polymer (solid, liquid, or semi-solid): The physical state of the polymer can affect the glass transition temperature measurement. Different states can exhibit different glass transition temperatures.
  • Presence of impurities or additives: Impurities or additives present in the polymer can influence the observed glass transition temperature. These substances can alter the polymer's molecular structure and affect its behavior during the glass transition.

Role in material applications

The glass transition temperature influences the choice of polymers in various industries and applications, including:

  • Automotive and aerospace: The Tg of polymers used in automotive and aerospace applications is critical, as it determines their ability to withstand high-temperature environments and maintain dimensional stability.
  • Consumer goods and electronics: The Tg influences the selection of polymers for consumer goods and electronic devices. Polymers with suitable Tg values are chosen to ensure durability, impact resistance, and resistance to heat and aging.
  • Medical and healthcare sector: The Tg of polymers used in medical and healthcare applications is essential for ensuring biocompatibility, sterilizability, and resistance to various environmental factors.

This diverse range of applications highlights the glass transition temperature's crucial role in tailoring polymer properties to meet specific requirements. Contact our engineers if you need to choose a protective coating material with a particular glass transition temperature and require assistance or learn more about thin film protection capabilities, such as coefficient of linear expansion, thermal conductivity, or optical properties, such as refractive index or transparency.

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What is Coefficient of Linear Expansion? Formula, Units & More

September 21, 2023 / by Mallory McGuinness-Hickey posted in Coating Properties, Thin Film Applications

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Temperature affects the behavior of materials, causing them to expand or contract. However, not all materials respond to temperature variations in the same way. Some materials, like metals, tend to expand when heated, while others, like water, show a more complex behavior, with expansion occurring at specific temperatures.

Learn about other thermal coating properties, like thermal conductivity and glass transition temperature

This property is crucial in predicting how a material will respond to temperature changes. This coefficient, represented by the Greek letter alpha (α), describes how much a material expands per unit length for each degree of temperature rise. Understanding this concept helps engineers make accurate predictions and design structures that can withstand temperature fluctuations.

Formula for Calculating the Coefficient of Linear Expansion

The coefficient of linear expansion (α) can be calculated using the following formula:

α = ΔL / (L₀ × ΔT)

Where:

α is the coefficient of linear expansion

ΔL is the change in length

L₀ is the original length

ΔT is the change in temperature

Units used for expressing the coefficient

The coefficient of linear expansion is typically expressed in units of length per unit temperature, such as millimeters per degree Celsius (mm/°C) or inches per Fahrenheit (in/°F). These units emphasize the linear dimensions and temperature change required to induce a specific change in length. By using consistent units, scientists and engineers can easily compare and analyze the behavior of different materials.

Measurement and Units

Accurately measuring values is essential in understanding how materials respond to changes in temperature. Several experimental techniques are commonly employed to measure the coefficient of linear expansion. The most widely used method is known as the thermal expansion apparatus. This apparatus consists of a rod or sample material, which is heated or cooled while its length changes are recorded. By carefully analyzing the recorded data, researchers can calculate the coefficient of linear expansion for the material.

The interferometric method utilizes interference patterns created by light passing through a material. This technique accurately measures the changes in length resulting from thermal expansion.

Additionally, some advanced techniques like dilatometry, which involves measuring volume changes, and strain gauges, which record dimensional changes, are used for highly precise measurements of the coefficient of linear expansion.

Relationship between the Coefficient of Linear Expansion and Thermal Expansion

Thermal expansion refers to the increase in size or volume of a material as its temperature rises. This expansion occurs because heat causes the atoms and molecules within the material to move more rapidly, increasing their average spacing. As a result, the material takes up more space and expands.

Meanwhile, the coefficient of linear expansion represents the change in length per unit length per unit change in temperature.

The relationship between the coefficient of linear expansion (α) and thermal expansion can be expressed using the following formula:

Thermal expansion = coefficient of linear expansion × Original length × Change in temperature

This formula allows engineers to calculate a material's dimensions change when its temperature changes.

Factors Influencing the Coefficient 

Several factors can influence the coefficient of linear expansion in materials. These factors can affect how much a material expands or contracts when subjected to changes in temperature.

 Crystal Structure, Bonding Types, and Impurities

The crystal structure of a material heavily influences the coefficient of linear expansion. Different crystal structures can lead to variations in the coefficient. The type of bonding between atoms in a material can also affect its coefficient. For example, materials with stronger intermolecular forces tend to have lower coefficients, while those with weaker ones tend to have higher ones.

Impurities in a material can also impact its coefficient of linear expansion. Their presence can disrupt the regular arrangement of atoms, causing changes in the expansion behavior.

External Factors

External factors such as pressure, magnetic fields, and electric fields can also influence this value. Pressure can alter the arrangement of atoms in a material, affecting its expansion behavior. Similarly, magnetic fields and electric fields can cause changes in the alignment and movement of atoms, leading to variations in the coefficient.

Material Selection

This property is highly dependent on the material properties of a substance. Different materials exhibit different coefficients due to their unique structures and bonding arrangements. For example, materials with stronger intermolecular forces tend to have lower values because their particles are held tightly together, making them less likely to expand significantly with temperature changes.

Material properties such as elasticity, rigidity, and thermal conductivity also play a significant role in determining this value. Elastic materials can return to their original shape after being subjected to deformation caused by thermal expansion. On the other hand, rigid materials are less prone to significant expansion due to their stiffness and resistance to deformation.

Additionally, materials with high thermal conductivity tend to have higher values. High thermal conductivity allows for faster heat transfer, leading to greater expansion or contraction in response to temperature changes.

When dimensional stability is critical, materials with low coefficients are preferred to minimize undesired expansions or contractions. On the other hand, materials with higher coefficients may be utilized in applications where controlled expansion is desired.

Engineers can make informed decisions regarding material selection, product design, and manufacturing processes by understanding how different materials expand or contract with temperature changes. This knowledge helps create efficient and durable structures, products, and systems. If you are looking for a coating material to suit your application needs, please contact our engineers to discuss DFM. Or, learn more about thin film protection capabilities, such as optical properties like transparency and index of refraction.

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What is Thermal Conductivity? Explanation, Measurement, Uses

September 21, 2023 / by Mallory McGuinness-Hickey posted in Protection Capabilities, Coating Properties

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Thermal conductivity is a fundamental concept in heat transfer and is crucial in multiple industries and scientific disciplines. It refers to the ability of a material to conduct heat or the rate at which heat transfers through a substance. Understanding this property is essential for designing efficient thermal systems, optimizing energy usage, and ensuring the safety and performance of various materials and products.

Learn about other thermal coating properties like glass transition temperature and linear coefficient of expansion.  

Fundamentals of Heat

Understanding heat and its relationship to thermal conductivity is essential in grasping the concepts of heat transfer. Heat, in its simplest form, transfers energy from one object to another due to temperature differences.

Temperature gradient plays a significant role. A temperature gradient refers to the difference in temperature between two points in a material or between two adjacent materials. Heat transfer occurs when there is a temperature gradient, with heat flowing from regions of higher temperature to regions of lower temperature.

This phenomenon is driven by the basic principle of nature - the tendency of a system to seek equilibrium. When there is a temperature difference, the system will naturally attempt to balance the temperatures, leading to heat transfer and thermal conductivity.

The Physics Behind Thermal Conductivity

Thermal conductivity is a fascinating concept deeply rooted in the fundamental principles of physics. At its core, thermal conductivity is defined as the ability of a material to conduct heat. This ability is determined by various physical factors that govern the flow of heat energy.

The mechanisms of heat conduction can explain this property at the molecular level. Heat conduction occurs when a temperature is different between two points in a material. In simple terms, it is the movement of heat energy from higher-temperature to lower-temperature regions.

One of the fundamental relayed principles is the concept of thermal resistivity. This refers to a material's resistance to the flow of heat. Materials with lower thermal resistivity have higher thermal conductivity, allowing heat to be transferred more easily.

Another essential principle is the role of atomic and molecular interactions. Heat energy is transferred through these interactions as atoms or molecules collide and exchange kinetic energy. A material's structure and arrangement of atoms or molecules can greatly impact its values.

Measurement Techniques

Measurement techniques are crucial in providing accurate data to understand thermal conductivity. Various experimental methods have been developed to measure thermal conductivity, each with advantages and limitations.

Overview of Experimental Methods

Experimental methods for measuring involve subjecting the material to controlled thermal conditions and observing the resulting heat transfer. These methods can be broadly classified into steady-state and transient techniques.

  • Steady-State Heat Flow: This method involves establishing a steady-state heat flux through the material and measuring the temperature gradient. Knowing the sample's dimensions and the temperature difference, the value can be calculated using Fourier's Law of heat conduction.
  • Transient Hot Wire Method: A thin wire with a known value is placed in contact with the material in this technique. A constant heat flux is applied to the wire, and the temperature rise is measured. By analyzing the rate of temperature change, thermal conductivity can be determined.
  • Laser Flash Analysis: Laser flash analysis is commonly used to measure thermal conductivity in solids. This method applies a short pulse of laser light to one end of the sample, creating an instantaneous temperature rise. The temperature decay is then measured and analyzed to calculate the value.

Non-Destructive Testing Techniques

Non-destructive testing techniques are commonly employed when measurements must be taken on finished products or structures without altering their integrity. These methods offer convenience and allow for thermal conductivity measurements in real-world applications.

Some non-destructive testing techniques commonly used for measuring thermal conductivity include infrared thermography, ultrasound, and thermal wave analysis. These techniques utilize the principles of heat transfer and allow for non-intrusive measurement of thermal conductivity in various materials.

Applications of Thermal Conductivity

The concept of thermal conductivity is essential in designing and optimizing thermal insulation materials to reduce heat loss or gain. It is also pivotal in developing efficient heat exchangers, such as those used in HVAC systems, refrigeration units, and power plants.

Additionally, it is a key factor in determining the performance and efficiency of electronic devices, such as computer processors and power electronics. Optimizing this value helps dissipate heat generated by these devices, preventing overheating and ensuring longevity.

Here are some examples of the wide-ranging applications of thermal conductivity:

  • Designing heat sinks for electronic devices: This property helps dissipate heat generated by components, ensuring optimal performance and preventing overheating.
  • Energy recovery systems: Energy recovery systems aim to capture and utilize waste heat generated by industrial processes. By efficiently transferring heat, it enables the conversion of waste heat into usable energy, reducing energy consumption and costs.
  • Enhancing thermal management in engineering applications: The property helps design and optimize cooling systems, ensuring efficient heat dissipation and preventing equipment failure due to overheating.

Due to the importance of this material property, selecting a protective coating material with the most suitable value is paramount. Please get in touch with us if you are a design engineer and have questions about protective coatings for electronic components. Otherwise, learn more about protective coating protection properties, such as optical properties like refractive index and transparency.

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What is the Index of Refraction? Measurement, Definition & More

September 20, 2023 / by Mallory McGuinness-Hickey posted in Protection Capabilities, Coating Properties

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Understanding how light travels through different mediums is essential in optics. One invaluable optical property is the index of refraction. This measurement quantifies how much a ray of light bends when it passes from one medium to another. The index of refraction plays a crucial role in understanding the behavior of light in various optical devices and phenomena.

Read more about transparent polymers.

Definition of the Index of Refraction

The index of refraction is a numerical value that represents the ratio between the speed of light in a vacuum and the speed of light in a given material. It determines how much the direction of light changes as it passes through a medium, such as air, water, or glass.

The higher the value, the slower light travels through the material, resulting in a greater bending or refraction of the light ray. This is due to the interaction between the electromagnetic waves of light and the charged particles within the medium.

Measurement Methods 

Several methods exist to accurately measure the index of refraction. Here are some widely used techniques:

  • Using refractometers: Refractometers are optical devices that determine the index of refraction by measuring the angle at which a light ray bends when passing through a sample material.
  • Employing mathematical models based on the speed of light: This involves calculations using mathematical equations that incorporate the speed of light in a vacuum and the speed of light in a particular medium. These models consider variables such as wavelength and frequency to derive the index value accurately.
  • Snell's Law: Snell's Law is a fundamental principle that relates the angles of incidence and refraction between two mediums. By measuring these angles and applying Snell's Law, the index of refraction can be determined.
  • Speed of Light: Another way to measure the index of refraction is by comparing the speed of light in a vacuum to the speed of light in a particular medium. This method requires precise measurements of the speed of light and the refractive properties of the medium.
  • Critical Angle: When light travels from a medium with a higher refractive index to a medium with a lower refractive index, it can reach a critical angle at which total internal reflection occurs. By measuring this critical angle, the index of refraction can be determined.
  • Dispersion: Dispersion refers to the phenomenon where different wavelengths of light (colors) refract at different angles when passing through a medium. By studying the dispersion of light, scientists can derive the index of refraction for each wavelength, creating a refractive index spectrum.

These measurement techniques allow engineers to understand better how light interacts with matter.

Refractive Index and the Speed of Light

Light, as we know, travels at an incredible speed through space. However, when it enters a medium, such as glass or water, its speed is significantly reduced due to the phenomenon of the index of refraction. Understanding the relationship between the index of refraction and the speed of light is crucial in various scientific and practical applications.

Why light travels slower in mediums with higher refractive indices:

When light passes through a medium, it interacts with the atoms and molecules in that medium. These particles cause the light to slow down as it continuously gets absorbed and re-emitted. The higher the refractive index of the medium, the more significant this effect becomes, resulting in slower light propagation.

Effects of different materials on the speed of light propagation:

Materials with higher refractive indices, such as diamond or glass, slow down light considerably. In contrast, materials with lower refractive indices, such as air or vacuum, allow light to travel at its maximum speed. This variance in speed is why light bends or changes direction when passing from one medium to another.

Index of Refraction and Product Design

The index of refraction has numerous practical applications in various fields. One application is the design of optical fibers, lenses, microscopes, telescopes, and other devices. By manipulating the path of light through different materials with different refractive indices, engineers can achieve desired outcomes such as focusing, magnification, and dispersion.

Additionally, understanding the behavior of light as it interacts with different materials allows engineers to develop and improve optical instruments. These instruments, ranging from cameras to spectrometers, rely on the principles of the index of refraction to function effectively.

If you are working on an application that requires a protective coating with certain optical properties, HZO might be able to help. Please contact us to speak to an engineer. Or, if you are more interested in learning about protective coating capabilities, read about thermal conductivity, linear coefficient of expansion, or glass transition temperature.

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Tensile Strength at Yield - Testing, Standards, Specs, Material

September 19, 2023 / by Mallory McGuinness-Hickey posted in Protection Capabilities, Coating Properties, Thin Film Applications

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The ability to accurately predict the behavior of coating materials under tension is crucial in ensuring the integrity and reliability of electronic components. This includes studying different materials' deformation and failure mechanisms when subjected to a tensile load. One key parameter that is used to quantify the ability of a material to withstand such loads is its tensile strength at yield.

What is Tensile Strength at Yield?

Tensile Strength at Yield indicates a material's ability to withstand loads and forces during its lifetime, making it crucial for designing structures and components that can endure various stresses. It is a vital measurement in numerous disciplines, such as engineering, manufacturing, aerospace, and automotive.

When a material is subjected to a tensile load, it experiences stress and undergoes deformation. The stress-strain curve, representing the relationship between the applied stress and resulting strain, provides valuable insights into the material's behavior. This curve can determine the ultimate tensile strength, the maximum stress the material can withstand before failure occurs.

The yield point is a critical parameter in studying tensile strength at yield. It refers to the point on the stress-strain curve where a significant increase in strain occurs with minimal or no increase in stress. The tensile strength at yield is the stress level at this point and represents the maximum stress a material can withstand without undergoing permanent deformation.

During the deformation process, materials can exhibit different types of behavior. Elastic deformation occurs when a material returns to its original shape upon removal of the load, while plastic deformation occurs when the material undergoes permanent changes in shape. Understanding the concepts of elastic and plastic deformation is essential in analyzing a material's behavior under tension.

Testing Methods, Equipment, and Standards Used for Measurement 

Due to the importance of this mechanical material property, obtaining accurate Tensile Strength at Yield data is critical. Accurately measuring it requires appropriate testing methods, equipment, and adherence to specific standards. The most commonly used technique is the tensile test, where a sample material is subjected to an increasing axial load until it reaches its yield point. Sophisticated equipment, such as universal testing machines, performs these tests and obtains reliable measurements. Standard organizations, such as ASTM International, provide guidelines and standards for conducting these tests, ensuring consistency and comparability of results.

Standards and Specifications 

Standards and specifications are crucial in ensuring the accuracy, reliability, and consistency of measurements. National and international organizations have established various standards to regulate this critical characteristic of materials.

Similarly, numerous national and international standards have been developed to guide the measurement and characterization of tensile strength at yield. These standards outline the specific testing methods, equipment, and conditions to ensure accurate and comparable results across different laboratories and industries.

The American Society for Testing and Materials (ASTM), International Organization for Standardization (ISO), and Deutsches Institut für Normung (DIN) are among the leading organizations that have established widely recognized standards for tensile strength at yield. Compliance with these standards is essential in ensuring test data's uniformity, reliability, and compatibility.

What Influences Tensile Strength at Yield?

Material composition plays a crucial role in determining values. Different elements and their proportions can significantly affect the mechanical properties of a material, including its yield strength. For example, increasing the amount of carbon in certain materials can enhance tensile strength at yield.

The microstructure of a material also plays a vital role in determining this value. Factors such as grain size, phase distribution, and dislocation density can impact the material's ability to withstand deformation before yielding.

Coating Material Selection and Design Factors

Because this mechanical property is crucial in determining various structures and products' overall reliability and safety, it should be closely considered during material selection. Every industry and application has unique requirements for choosing a coating material. Engineers must account for environmental conditions, load-bearing capacity, and durability requirements. They can select appropriate materials to meet the desired performance and safety standards by evaluating the tensile strength at yield requirements specific to each industry. A summary of requirements for particular applications is below.

Evaluating Tensile Strength at Yield requirements for different industries

  • Aerospace: In the aerospace industry, where extreme conditions and rigorous performance requirements exist, coating materials with exceptional tensile strength at yield are crucial. This property ensures aircraft components' structural integrity and safety, such as wings and fuselage, under immense stress during flight.
  • Automotive: This property is vital in automotive engineering as it affects vehicle structural stability. Manufacturers and designers prioritize coating materials with optimal values to enhance passenger safety and overall vehicle performance.
  • Consumer products: From household appliances to sports equipment, consumer products are designed to withstand daily usage and potential impacts. Tensile strength at yield is vital in ensuring that these products can withstand the forces they are subjected to without deforming or failing.

Importance in Coating Material Selection

Tensile strength at yield is a critical mechanical property used in coating material selection. It provides valuable information about the protective coating material's ability to withstand applied forces without permanent deformation. If a protective coating were to break, it could allow corrosives and contaminants to destroy electronic components, causing failure.

Design engineers rely on this property to evaluate and compare different coating materials, ensuring their suitability for specific applications. If you are designing an electronic component and need help determining which coating material is best for your product, please contact our engineers, or read additional information on thin film coating properties.

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Elongation at Break - Definition, Testing, Material Selection

September 19, 2023 / by Mallory McGuinness-Hickey posted in Protection Capabilities, Coating Properties, Thin Film Applications

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Elongation at break is a key mechanical property that measures the deformation capacity of a material before it eventually snaps or breaks, providing insights into the material's behavior and performance. This crucial measurement is closely related to tensile strength, which determines a material's ability to withstand pulling forces without breaking.

The longer the elongation at break, the greater the material's flexibility and ductility. It represents how much a material can stretch or elongate under tension before reaching its breaking point.

In metals, elongation at break showcases malleability and ensures they can withstand deformation without fracturing easily. Plastics with higher elongation at break are more capable of enduring stress and strain without undergoing permanent damage. Understanding the importance of elongation at break helps select the right materials for diverse applications, ensuring optimal performance and durability.

Testing Methods for Elongation at Break

Elongation at break is a key indicator of a material's ability to stretch before reaching its breaking point, so accurate data is vital for material selection. To precisely determine this value, various testing methods are employed.

When conducting tests, manufacturing and quality control considerations play an essential role. These considerations include:

  • Ensuring that sampling is representative of the material being tested.
  • Using appropriate and calibrated testing equipment to obtain accurate measurements.
  • Following standardized testing procedures to maintain consistency.

By considering these factors, manufacturers can ensure the reliability and integrity of their testing results, which are critical for maintaining consistent material properties. Two methods of testing are described below.

Tensile Testing

Tensile testing involves subjecting a material sample to tension until it fractures. The sample is held between two clamps and pulled in opposite directions until it breaks. The amount of elongation before fracture is recorded and used to calculate the final value.

Elongation Testing

Elongation testing is another method utilized for measurement. Unlike tensile testing, this method focuses solely on measuring the elongation of a material sample without causing it to fracture. The sample is stretched until a specified strain value is achieved, and the resulting elongation is measured.

How to Calculate Elongation at Break

The elongation of the material sample at the point of fracture is measured by comparing the original length of the sample to its final length after fracturing. The percentage of elongation is then calculated by dividing the change in length by the original length and multiplying by 100.

Mechanical Properties and Plastic Deformation

Elongation at break is just one of the mechanical properties used to assess a material's performance. It is closely related to other properties like yield strength, resilience, and plastic deformation. Manufacturers often evaluate it alongside these properties to comprehensively understand a material's behavior.

For example, this property is a valuable measure of a material's ability to undergo plastic deformation. Plastic deformation refers to the permanent change in the shape of a material when subjected to stress. Materials with high elongation at break have greater plasticity and can undergo significant deformation without fracture.

Understanding the relationship between elongation at break and plastic deformation is crucial in various industrial applications. It allows engineers and manufacturers to select materials that can withstand the required stress and deformation without failure.

Consideration of Elongation at Break in Material Selection

Elongation at break is also widely used for material comparisons and benchmarking. By evaluating and selecting appropriate materials based on their desired levels of ductility and flexibility, industries can ensure that their products perform optimally under different operating conditions.

Materials with higher values are generally preferred in applications where the material needs to undergo extensive deformation without failure. On the other hand, materials with lower values may be desired for applications where high rigidity and resistance to deformation are required.

By considering elongation at break, engineers can make informed decisions regarding material selection and performance optimization, enhancing product reliability and customer satisfaction. If you are designing an electronic product that needs protective coatings and are having trouble identifying which material to choose, please contact our Applications Engineers for answers. Or if you are interested in learning more about thin film protective coating capabilities, such as such as elongation yield or Young's modulus of polymers, browse our site.

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Young's Modulus of Polymers - Measurement, Calculation

September 19, 2023 / by Mallory McGuinness-Hickey posted in Protection Capabilities, Coating Properties, Thin Film Applications

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Young's Modulus is an important property, allowing engineers to select coating materials based on their desired stiffness. Understanding and manipulating the elastic Modulus of polymers is crucial for applications where strength, flexibility, or a combination of both is required.

What is Young's Modulus of Polymers?

Young's Modulus, also known as the elastic Modulus, is a fundamental property that characterizes the mechanical behavior of a material. It quantifies the relationship between stress (force per unit area) and strain (deformation) when a material is subjected to an external force or load.

For polymers, Young's Modulus determines how much the material will stretch or compress in response to applied stress. It measures the rigidity of the polymer chain structure. When comparing Young's Modulus between polymers and other materials such as metals and ceramics, polymers typically have lower values. This is because polymers have a more flexible molecular structure, allowing them to undergo more significant elastic deformation under applied stress, in contrast to metals and ceramics with more rigid atomic structures.

Factors Influencing Young's Modulus 

Understanding the factors influencing Young's Modulus allows engineers to choose polymer materials with desired mechanical properties for specific applications. The following factors influence Young's Modulus of Polymers:

  • Molecular structure and chain flexibility: The arrangement and size of polymer chains determine their flexibility and, consequently, their Young's Modulus. Polymers with longer and more linear chains tend to have higher Young's Modulus values.
  • Degree of cross-linking and polymerization: Cross-linking refers to forming chemical bonds between polymer chains, increasing their rigidity and thus increasing Young's Modulus. Higher degrees of cross-linking result in higher Young's Modulus values.
  • Temperature and environmental conditions: Young's Modulus of polymers can vary with temperature and environmental conditions. The presence of moisture, for example, can affect the intermolecular forces within the polymer, leading to changes in Young's Modulus.

Measurement and Calculation of Young's Modulus

Measuring and calculating Young's Modulus is crucial to understanding the mechanical behavior of polymers. This value provides valuable insight into how a polymer will respond to applied stress and strain, making it essential in product design.

There are various experimental techniques used to measure Young's Modulus in polymers. These include:

  • Tensile testing and stress-strain curves: This technique involves subjecting a polymer sample to tension until it reaches its breaking point. The resulting stress-strain curve provides essential data for determining Young's Modulus.
  • Extensional methods: Uniaxial and biaxial extension tests measure Young's Modulus in specific directions. These methods help evaluate the anisotropic nature of polymers.
  • Other characterization techniques: Techniques such as nanoindentation and dynamic mechanical analysis can also be employed to measure Young's Modulus in polymers.

Calculation methods for Young's Modulus

Hooke's Law and stress-strain behavior interpretation play vital roles when calculating Young's Modulus:

  • Hooke's Law and its application to polymers: Hooke's Law states that the stress applied to a material is directly proportional to the strain it produces. This linear relationship allows for the calculation of Young's Modulus.
  • Interpretation of stress-strain behavior and determination of Modulus: By analyzing the stress-strain curve obtained from experimental data, the Modulus can be determined using mathematical methods tailored for polymers.

Role in Material Selection and Design

Young's Modulus helps engineers determine the stiffness and elasticity of polymers. Knowing Young's Modulus values allows them to select the appropriate material for a specific application. The higher the Young's Modulus, the stiffer the material will be, resulting in better resistance to deformation. This stiffness is crucial in applications where the polymer needs to withstand heavy loads or maintain its shape for a long time.

Some examples of how design engineers use Young's Modulus to select materials in different industries are listed below.

  • Automotive and aerospace applications: Young's Modulus is essential in designing components such as automotive body parts, airplane wings, and fuselages. It helps engineers ensure the materials can withstand the required forces and maintain their shape during operation.
  • Medical and healthcare applications: Young's Modulus is a consideration when developing medical devices, prosthetics, and implants. The Modulus ensures that the materials provide the necessary support, flexibility, and performance for patient safety and comfort.
  • Consumer goods and packaging: Young's Modulus comes into play in designing everyday products such as bottles, containers, and packaging materials. It helps determine the polymers' rigidity, flexibility, and impact resistance, ensuring they meet the specific requirements of the intended applications.
  • Industrial applications: Engineers can use the measure of stiffness or rigidity of a material to predict how polymers will behave under various conditions common in harsh industrial environments.

Relationship Between Young's Modulus and Product Performance and Durability

Because Young's Modulus directly affects a polymer's behavior under different loads and stresses, engineers can make informed decisions about material selection, design structures that can withstand specific loads, and ensure the safety and reliability of polymer-based products.

The knowledge of Young's Modulus allows for optimizing material properties, such as flexibility and strength, to meet the unique requirements of various industries. Whether in the automotive, aerospace, or medical field, an understanding of Young's Modulus enables the development of innovative solutions that are tailor-made for specific applications.

If you are an engineer involved in product design and would like guidance in selecting a suitable coating material for your application, please contact our team today. Alternatively, if you want to learn more about thin film properties, including elongation yield, elongation at break, or tensile strength at yield, browse our site. 

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Water Vapor Transmission Rate - Standards, Testing, Material

September 14, 2023 / by Mallory McGuinness-Hickey posted in Protection Capabilities, Coating Properties, Thin Film Applications

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In the world of electronics, moisture control is of utmost importance. High water vapor transmission rate (WVTR) can pose significant risks to sensitive electronic devices. When moisture enters electronic components, it can lead to various issues, including corrosion, short circuits, and malfunctioning. These risks can result in costly repairs, product failures, and even safety hazards.

Manufacturers continually strive to create smaller, faster, and more powerful electronics. However, these advancements also often make the devices more susceptible to moisture damage. Implementing effective moisture control measures during the design and manufacturing process is essential to ensure the longevity and reliability of electronic components.

Water vapor transmission refers to the movement of water vapor through a material or substance. The water vapor transmission rate is a pivotal property for moisture control, and as such, measuring and managing WVTR is a priority in many applications.  

 

Understanding Water Vapor, Transmission, and Vapor Transmission

Water vapor refers to the presence of water in a gaseous state. Under certain temperature and pressure conditions, water vapor can condense into liquid water.

Transmission refers to the movement of any substance, whether liquids, gases, or solids, from one side of a barrier to the other. This movement can occur through various means, such as diffusion, permeation, or evaporation. Vapor transmission, on the other hand, specifically relates to the movement of water vapor molecules through a barrier.

Vapor transmission plays a crucial role in moisture control. Without the ability for water vapor to move freely through materials, moisture can become trapped, leading to mold growth, structural damage, and product degradation. By allowing water vapor to escape, vapor transmission helps prevent excessive moisture buildup.

 

Factors affecting vapor transmission

Several factors influence the rate of vapor transmission. These include temperature, pressure, and humidity.

  • Temperature variations can affect the rate water molecules transition between vapor and liquid states. Higher temperatures generally increase the speed of vapor transmission.
  • Pressure differentials between the two sides of a barrier can also impact vapor transmission. In some cases, pressure differentials can hinder or enhance the movement of water vapor.
  • Humidity levels, which measure the amount of water vapor in the air, can greatly influence vapor transmission. Higher humidity often leads to higher vapor transmission rates, while lower humidity may restrict the movement of water vapor through materials.

 

Water Vapor Transmission Standards and Testing

The ASTM standards outline the procedures and techniques for conducting WVTR tests, ensuring consistency and accuracy across different laboratories and testing facilities. These standards provide guidelines on sample preparation, test conditions, and data analysis, allowing for reliable and comparable results.

Overview of Permeability Testing Methods and Techniques

Permeability testing refers to the evaluation of how easily water vapor can permeate through a material or film. Several methods are available to measure WVTR, including the gravimetric method, the desiccant method, and the electrical measurement method. Each method has its advantages and limitations, and the choice of method depends on factors such as the material being tested and the required accuracy. You can read more about these methods here

Importance of Accurate Testing for Reliable WVTR Results

Accurate testing determines a material's true water vapor transmission rate. By following ASTM standards and utilizing appropriate testing methods, manufacturers can ensure that their products meet the necessary performance requirements and provide optimal moisture control.

Learn about relevant standards such as Ingress Protection Standards and NEMA Ratings.

 

Film and Polymer Materials

Thin films play integral roles in creating effective moisture barrier systems. These materials are designed to prevent water vapor passage, thereby protecting products and structures from moisture damage.

Specific properties and characteristics become priorities when evaluating coating materials for moisture control. Engineers should consider the following:

  • Water vapor permeability: measures how easily water vapor can pass through a material. Lower permeability indicates better moisture resistance.
  • Tensile strength: the ability of the coating material to resist breaking or tearing under tension
  • Elongation at break: The maximum elongation or stretch a material can undergo before breaking. Higher elongation allows for flexibility and resistance to tearing.
  • Chemical resistance: the resistance of the material to chemical substances, preventing degradation and maintaining its moisture control properties
  • Transparency: In specific applications, it is essential for the polymer material to maintain transparency, allowing consumers to evaluate products visually.

If you need a coating material with a low water vapor transmission rate or have questions about choosing suitable materials, contact our Applications Engineers for a DFM consult. Or, you can learn more about protective thin film coating properties.

 

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Transparent Polymers - Applications, Material Selection

September 14, 2023 / by Mallory McGuinness-Hickey posted in Protection Capabilities, Coating Properties, Thin Film Applications, Value of Coatings

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Transparent polymers offer optical clarity and the ability to transmit light. With various applications across various industries, these polymers have gained popularity for their unique properties and versatility. Common transparent polymer types include acrylics, polycarbonates, parylenes, and polyurethanes. The molecular arrangement and morphology of transparent polymers play a crucial role in their transparency. Transparent polymers typically comprise transparent monomers that polymerize to form a solid material. A uniform and amorphous structure is of paramount importance in achieving optical clarity.

Read about refractive index, another optical property.

Applications of Transparent Polymers in Various Industries

Optics and Optical Devices

Transparent polymers are extensively used to produce lenses, optical fibers, LEDs, and displays. Due to their excellent optical clarity and refractive properties, these polymers contribute to the functionality and performance of these devices. They enable the transmission and manipulation of light, essential for achieving optimal performance in optics and optical devices.

Coatings and Films

Transparent polymer coatings and films are widely used for various applications, including protection, durability, and aesthetic enhancement. These coatings and films are applied on glass, metals, and electronics surfaces to provide a protective layer while maintaining transparency. Transparent polymer coatings and films also resist scratches, chemicals, and UV radiation.

Renewable Energy

They play a significant role in the fabrication and encapsulation of solar panels. They are transparent encapsulant materials that allow sunlight to be absorbed and transmitted to the photovoltaic cells within the solar panels. Transparent polymers help maximize the efficiency of solar panels by ensuring optimal light absorption and transmission.

Biomedical Applications

These polymers are extensively used in biomedical imaging, drug delivery systems, and tissue engineering. They enable clear visualization in imaging techniques and provide a platform for developing advanced drug delivery systems.

Displays and Electronics

Some of these polymers play a crucial role in the development of touch screens, flexible displays, and transparent conductive films used in electronics. They enable light transmission while providing electrical conductivity, making them essential components in the construction of displays and electronic devices. They also contribute to the production of sleek and high-performance electronic devices.

Coating Material Selection

Transparency, durability, and versatility make these polymers ideal for numerous applications. Transparent polymers enable technological advancements and enhanced user experiences from optical lenses to display screens. If you require this type of coating material for your product design and would like to speak to an engineer, HZO can help. Reach out today. Or, you can stay and read more about coating properties, including thermal conductivity, linear coefficient of expansion, and glass transition temperature

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Biocompatible Coatings - Coating Techniques, Applications, More

September 13, 2023 / by Mallory McGuinness-Hickey posted in Protection Capabilities, Coating Process, Coating Properties, Thin Film Applications

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Biocompatible coatings seamlessly integrate with the human body, offering benefits through their ability to promote healing and prevent adverse reactions. They can improve patient outcomes, reduce complications, and enhance device functionality. As such, biocompatible coatings have become an indispensable tool in various medical applications.

 

What is Biocompatibility, and What Affects the Biocompatibility of Coatings?

 

Biocompatibility refers to the ability of a material to function without causing any harmful effects to the living tissues or organs it comes into contact with.

Several factors influence the biocompatibility of coatings. One such factor is the material composition. The choice of materials used in a coating can significantly impact its compatibility with the human body. Additionally, the surface properties of the coating play a vital role in determining its biocompatibility. Roughness, porosity, and surface energy can affect how the coating interacts with biological tissues and fluids.

When it comes to achieving biocompatibility in coatings, there are key considerations. First and foremost, the material should be non-toxic and non-allergenic. It should not trigger any adverse immune responses or elicit any toxic effects. Furthermore, the coating should withstand the physiological environment it will be exposed to, such as changes in pH, temperature, and mechanical stress.

Coating application processes also play a significant role in achieving biocompatibility. The application technique must ensure uniform coverage and adherence. Proper surface preparation and application techniques are essential to avoid issues arising from poor coating adhesion or inconsistencies.

 

Why are Biocompatible Coatings Important?

Biocompatible coatings can significantly influence the body's response to medical devices and implants. A well-designed biocompatible coating can minimize inflammatory responses, prevent bacterial adhesion, and promote tissue integration. Furthermore, by providing a protective and biologically compatible barrier, these coatings enhance the safety and effectiveness of medical devices, improving patient outcomes.

There have been several successful applications of biocompatible coatings in medicine and biomedical engineering. Here are a few examples:

  • Orthopedic implants: Biocompatible coatings have been used on orthopedic implants to improve their longevity and reduce inflammation and tissue rejection.
  • Drug delivery systems: Coatings have been developed to encapsulate and protect drugs, allowing for targeted delivery and controlled release within the body.
  • Stents: Biocompatible coatings on stents help to prevent blood clot formation and promote healing in cardiovascular applications.
  • Dental implants: Coatings on dental implants enhance biocompatibility, improving the integration of the implant with the surrounding bone.

 

Coating Technologies

Various coating technologies are employed to achieve biocompatibility in different medical devices. These technologies involve using specific materials and techniques to create coatings that meet the required standards:

Chemical Composition

Different biocompatible coating materials, including polymers, such as Parylene, ceramics, and metals, are used. Each type has its unique characteristics and advantages for medical applications. Polymers, for example, are known for their flexibility and ability to mimic natural tissues. Ceramics offer excellent wear resistance and can provide a stable surface for cell growth, while metals are valued for their durability and strength.

Coating Techniques

Each coating technique has its advantages and limitations. The selection of a particular method depends on factors such as the desired coating properties, the substrate material, and the intended application. The deposition of biocompatible coatings requires specific techniques to ensure uniformity and adherence to the substrate. Several coating techniques are commonly employed in the medical industry, including:

  • Chemical vapor deposition (CVD): In this technique, a precursor gas is introduced into a chamber and reacts to form a coating on the surface of the substrate. CVD offers excellent coating conformity and is frequently used for coating stents and catheters.
  • Electrochemical deposition: Also known as electrodeposition, this technique involves using an electric current to deposit a material onto a substrate. It is typical for coating electrodes and medical implants.
  • Dip coating: This technique entails immersing the substrate into a bath of the coating material and then withdrawing it at a controlled rate. Dip coating provides a uniform and controlled coating and is often used in the fabrication of medical devices.
  • Spray coating: The coating material is atomized and applied to the substrate in a fine spray. This is a popular technique for coating dental implants and prosthetics.

 

Biocompatible Coatings Applications

Biocompatible coatings can be employed in manufacturing electronic devices, food processing equipment, and cosmetic products, among others. With their ability to provide a safe and reliable surface, biocompatible coatings offer advantages beyond the medical field.

However, within various areas of medicine, biocompatible coatings play a crucial role in enhancing the compatibility of medical devices, improving tissue engineering techniques, and revolutionizing drug delivery systems. These coatings have transformed the field of medicine by reducing rejection and adverse reactions and improving the overall efficiency of medical interventions. Three use cases are described below.

Medical Implants

One of the critical applications of biocompatible coatings is in the field of medical implants. For instance, in orthopedic implants, biocompatible coatings create an optimal environment for the implant to integrate seamlessly with the surrounding tissues and bones. Similarly, dental and cardiovascular implants benefit from biocompatible coatings, promoting long-term stability and functionality.

Drug Delivery Systems

Biocompatible coatings have revolutionized the field of drug delivery systems by improving stability, enhancing bioavailability, and enabling targeted drug delivery. The efficacy and safety of drug delivery are significantly improved by coating drug carriers such as nanoparticles, microparticles, and implants with biocompatible materials. These coatings protect the drugs from degradation, facilitate controlled release, and ensure targeted delivery to specific tissues or cells.

Biomedical Devices

Biocompatible coatings find extensive applications in various biomedical devices, including biosensors, microfluidic devices, and prosthetics. These coatings enable seamless integration and interaction with biological systems, enhancing the device's functionality and reducing the risk of adverse reactions. For example, biocompatible coatings on biosensors allow accurate and reliable detection of biomarkers, while coatings on prosthetic limbs improve their integration with the human body and enhance user comfort and mobility.

 

Factors Influencing Biocompatible Coating Selection

Selecting the most suitable material for a specific application is essential to ensure optimal biocompatibility and overall performance of the coating. There are various factors to consider when selecting materials for specific medical applications. These factors include:

  • Chemical composition: The specific chemicals used in the coating formulation can significantly influence its biocompatibility with the surrounding environment.
  • Surface interactions: Understanding how the coating interacts with the surrounding biological tissues and fluids is crucial to ensure proper biocompatibility.
  • Thickness and uniformity: The thickness and uniformity of the coating play a vital role in its ability to protect the underlying substrate and provide the desired properties.
  • Physical properties: The physical properties, such as hardness, flexibility, and adhesion strength, must be considered when selecting a coating for a specific application.

Please contact our engineers if you require a biocompatible coating material for your application or have questions about protective thin film coating properties. Meanwhile, please browse our resource section to learn about other relevant properties, such as tensile strength, yield elongation, and corrosion resistance.

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Dissipation Factor - Definition, Measurement, Variables

September 12, 2023 / by Mallory McGuinness-Hickey posted in Protection Capabilities, Coating Properties

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Dielectric materials are crucial in various industries and applications, serving as insulators, substrates, or capacitors. One important characteristic often evaluated in dielectric materials is their dissipation factor. The dissipation factor, also known as the loss tangent or tan δ, is a vital parameter that measures the dielectric losses in electrical systems and components. It quantifies the energy dissipated as heat when an alternating current (AC) signal passes through an insulating material or a capacitor.

 

Why is Dissipation Factor Important?

This property provides valuable insight into the performance of dielectric materials. It measures the efficiency with which a dielectric material dissipates energy in the form of heat when subjected to an alternating current (AC) or high-frequency signal.

By analyzing this value, engineers can detect potential issues such as insulation breakdown, heat generation, and power loss, enabling them to effectively design and optimize electrical systems. Whether in high-frequency applications, power electronics, or telecommunications, the dissipation factor assists in selecting the appropriate materials, reducing energy loss, and enhancing electrical equipment's overall efficiency.
A high dissipation factor can indicate potential problems such as inefficient energy transfer or excessive heat generation in dielectric materials. By assessing this data, engineers can determine if a material is suitable for a specific application or needs replacing.

Measurement Techniques 

The dissipation factor is calculated by dividing the loss tangent of a dielectric material by its capacitance. The loss tangent is the ratio of the dissipated power to the stored energy in the material. There are several ways to determine the dissipation factor of various materials accurately. Professionals can use these techniques to obtain precise data and evaluate the performance and reliability of materials.

Bridge Method

The bridge method is a common measurement technique. It uses a bridge circuit consisting of resistors, capacitors, and inductors. By balancing the bridge, engineers can determine the material's dissipation factor under test.

Parallel-Plate Method

The parallel-plate method is another popular technique. It involves placing the material between two parallel plates and applying an alternating voltage across them. The dissipation factor is determined by measuring the power loss in the material.

Guard-Ring Method

The guard-ring method is a technique that minimizes the effects of stray capacitance during measurement. It involves placing a guard ring around the measurement electrodes to prevent current leakage due to the stray capacitance. This method helps to improve accuracy.

Variables Affecting Dissipation Factor

Several factors can influence the dissipation factor, affecting the efficiency and performance of electrical systems. Engineers and designers can optimize electrical systems by understanding and considering these factors, ensuring efficient and reliable operation.

Temperature

Temperature plays a significant role. As the temperature increases, molecular motion and energy losses increase, leading to a higher value. It is important to consider the temperature range in which a material will be used to ensure its dissipation factor remains within acceptable limits.

Dielectric Loss

Dielectric loss refers to the energy lost as heat due to the interaction between the electric field and the dielectric material. Materials with higher dielectric losses tend to have higher dissipation factors. Selecting materials with low dielectric loss can help minimize dissipation and improve system performance.

Frequency of Operation

The frequency of operation has a direct impact. At higher frequencies, the energy losses from the materials increase significantly, leading to an increased value. It is essential to consider the operating frequency when evaluating the dissipation factor of materials for electrical systems.

Resistance in the Circuit

The resistance in the circuit also contributes to the dissipation factor. Higher resistance causes larger energy losses and a greater value. Minimizing resistance through proper circuit design and selecting low-resistance components can help reduce the overall dissipation factor.

 Material Selection

The dissipation factor provides valuable insights into the electrical behavior of components, enabling manufacturers to make informed decisions regarding their application in different industries. This value is relevant across various industries heavily relying on electrical components. Industries such as telecommunications, power generation, aerospace, and automotive require strict adherence to quality standards to ensure optimal performance and safety.

Engineers can compare materials' performance at high frequencies by evaluating this property. This evaluation allows them to select materials with lower dissipation factors, which result in reduced energy losses and improved system efficiency. Furthermore, optimizing this property can also lead to increased power handling capabilities and improved reliability. If you are designing an electronic product and need help selecting a protective coating with beneficial electrical properties, please contact our team for a consultation. Or, you can learn more about thin film coating properties.

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Volume Resistivity - Definition, Measurement, Product Design

September 12, 2023 / by Mallory McGuinness-Hickey posted in Protection Capabilities, Coating Properties

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Whether designing circuit boards or protecting electrical components, knowledge of the volume resistivity of coating materials plays a pivotal role in creating efficient and reliable electronic products. This critical measurement refers to the ability of a material to resist the flow of electric current within its volume. In other words, it measures how well a substance conducts or insulates electricity.

Defining Volume Resistivity

Volume resistivity refers to a material's resistance per unit volume when an electric field is applied. It is measured in ohm-meters (Ω·m) and depends on the material's nature and composition.


One way to understand this property is by comparing it to electrical conductivity. While volume resistivity measures the resistance to the flow of current, electrical conductivity measures how easily current flows through a material. In other words, it is the inverse of electrical conductivity. Volume resistivity is especially important in coating materials used for electrical insulation. Insulating materials like polymers or ceramics need high values to prevent electrical current leakage and ensure the circuit's integrity.

Measurement 

Due to its importance, the accurate measurement of volume resistivity is essential to understanding the electrical conductivity of materials. By determining how well a coating material can resist the flow of electric current, engineers can assess its suitability for a wide range of applications.

Several techniques are common. One such method is the four-point probe technique, which involves passing a known current through a material and measuring the voltage drop across four evenly spaced points. This method enables precise calculations of the material's resistivity. Another popular technique is the two-point method. This approach passes a current through the material using two electrodes, and the voltage drop is measured. By applying Ohm's Law, the resistivity can be easily determined.

Specialized equipment is necessary to measure this value. This equipment includes multimeters, which can accurately measure voltage and current. Custom-built setups are often employed for specific applications to ensure precise measurement results.

Influencing Factors

Various factors can influence the volume resistivity of a coating material. These factors can alter the resistance properties of a material and potentially affect its performance in electrical applications. They include the following:

  • Material composition - the composition of a material plays a crucial role in determining its volume resistivity. Different materials have different electrical properties, which can significantly influence their resistance to electric current flow.
  • Molecular structure - materials with tightly packed and well-ordered molecular structures tend to have higher resistivity as the movement of free electrons is restricted.
  • Impurities - even small amounts of impurities can disrupt the movement of electrons, leading to changes in the coating material's electrical resistance.

Relationship Between Coating Materials and Volume Resistivity

Polymer materials have different volume resistivity values, determining their ability to conduct or resist electrical current. The volume resistivity of a polymer is directly influenced by its molecular structure and composition. Some examples of polymer materials with high values include polyethylene and polypropylene. These materials are commonly used in cable insulation and high voltage applications, where electrical current needs to be contained. On the other hand, polymer materials with low values, such as conductive polymers and carbon-filled composites, are often used as electrical conductors. They are suitable for applications requiring efficient electrical current flow.

Why is This Property Important for Product Design?

Volume resistivity is a critical value that helps determine the suitability of coating material for specific applications. Engineers can select the most appropriate materials to ensure optimal performance and safety by knowing how conductive or insulating a substance is. Additionally, understanding this property helps diagnose and prevent electrical failures in electronic products. Analyzing the volume resistivity of protective coating material within an electrical system allows potential issues, such as short circuits or unexpected voltage drops, to be identified and rectified before they cause significant damage or failures. This proactive approach saves time and money while enhancing the system's reliability. Last, volume resistivity is essential in complying with industry standards and regulations. Many sectors, including electronics, automotive, and aerospace, have stringent requirements for electrical systems. By ensuring that materials used in these systems possess the appropriate volume resistivity values, businesses can meet these standards and ensure the longevity of their products.

Significance in Circuit Design

In circuit design, selecting coating materials with appropriate volume resistivity is paramount. This property plays a significant role in ensuring electronic devices' proper functioning and performance. By selecting materials with appropriate volume resistivity, circuit designers can ensure the proper operation of different components, minimize the risk of electrical failures, and enhance the overall functionality of the circuit.

Overall, this is a critical factor to consider during circuit design. It not only influences the performance and efficiency of electronic devices but also allows for the optimization of circuit design by selecting materials based on their electrical properties. If you are searching for a protective coating with volume resistivity that meets the criteria for your application, please contact us; we may be able to help. For more information about the critical electrical properties of coating materials, please visit our coating properties page.

 

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UL94 Coating Material - Testing Method, Material Selection

September 8, 2023 / by Mallory McGuinness-Hickey posted in Protection Capabilities, Coating Properties

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Fire safety compliance is an indispensable aspect across various industries. One crucial benchmark in fire safety compliance is UL94, a widely recognized standard for flammability testing of plastic materials. By evaluating the flammability characteristics of different materials, UL94 ensures that products meet the required safety standards and regulations. 

What is UL94? 

UL94 is a standard for evaluating plastic materials' flammability in various industries. It provides an objective and reliable assessment of the fire resistance properties of these materials. 

UL94 is an abbreviation for Underwriters Laboratories Standard 94, first introduced in 1972. Underwriters Laboratories (UL) is a global safety certification company that tests and certifies a wide range of products for their safety and performance. UL94 is one of the many standards developed by UL to ensure the safety of products and materials. 

The role of this standard in product and material safety assurance cannot be overstated. It helps engineers and manufacturers identify potential fire hazards by clearly demonstrating materials' flammability properties. This information mitigates risks and leads to the development of safer products. 

Flame ratings, such as V-0, V-1, V-2, HB, etc., indicate a material's ability to self-extinguish or resist flame propagation. Materials with higher flame ratings provide greater confidence in the product's safety and fire resistance. Understanding these ratings is essential in assessing the fire performance of materials and ensuring their compliance with safety standards; therefore, accurate data is critical. 

Learn about other standards, such as Ingress Protection Standards and NEMA ratings.

Testing Methodology 

The UL94 testing methodology is a standardized procedure used to determine the flammability characteristics of materials. The UL94 testing methodology subjects test specimens to controlled flame exposure, providing valuable information to manufacturers, regulators, and consumers. 

Several test methods are used in testing, including vertical burn, horizontal burn, and others. Each test method simulates specific fire scenarios and assesses different aspects of a material's flammability. Before testing, specimens are prepared according to particular requirements. This preparation includes cutting them into proper dimensions, removing any surface coatings, and ensuring consistency in sample preparation across different tests. 

UL94 testing occurs under specific standard test conditions, such as ambient temperature and flame duration. These conditions simulate real-life fire scenarios and allow for reliable material comparisons. Flame ratings are assigned based on specific criteria, such as the material's ability to self-extinguish within a particular time frame or its resistance to flame propagation. These criteria vary depending on the test method applied. 

Material Selection 

Understanding the relationship between material characteristics and fire resistance is crucial when choosing suitable plastic materials. UL94 testing helps engineers evaluate different materials' flammability, ignition, and burning characteristics to select the most appropriate options, ensuring that the chosen materials meet safety requirements and minimize potential risks.

When selecting coating materials for specific applications, there are several key considerations. These include the intended use, environmental conditions, mechanical properties, and chemical and fire resistance. A comprehensive understanding of UL94 test results enables engineers and designers to make well-informed decisions regarding material selection. If you are looking for a UL94-rated protective coating material or have questions for our engineering team, please contact us today. Or you can learn more about thin film protective coating properties, such as dielectric constant, Young's Modulus, biocompatibility, and glass transition temperature.

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Elongation Yield: Overview, Unit of Measure, Data and Testing

August 29, 2023 / by Mallory McGuinness-Hickey posted in Protection Capabilities, Coating Properties

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Elongation yield refers to the maximum amount of deformation a material can undergo before it experiences a permanent change in shape or size. This property is fundamental in determining various coating materials' mechanical strength and behavior, making it an essential factor in design engineering and product design.  

Understanding how this property affects material performance is crucial in determining the suitability of coating material for a particular application. It directly affects the material's ability to deform without breaking and sustain loads without failure. This high-level overview will discuss elongation yield and its implications for product design. 

Elongation Yield: Material and Unit of Measure 

Elongation yield can be measured in various coating materials, including metals, polymers, and composites. Coating materials such as metals with higher values typically exhibit greater ductility, the measure of a material's ability to deform before fracture. 

On the other hand, coating materials with a lower elongation yield tend to be less ductile and more prone to brittle behavior. They have limited ability to deform before reaching their breaking point. Such materials are usually more suitable for applications that require high strength and rigidity but not necessarily significant deformation. 

Polymers, including plastics and rubber, display higher values than metals, enabling them to withstand extensive stretching or bending before breaking. 

Composites, which consist of two or more different material components, can possess varying characteristics depending on their composition. The individual materials within a composite can have different abilities to undergo elongation yield, making the overall behavior complex. 

Unit of Measure 

Two standard units of measure are used to quantify elongation yield: percentage and millimeters. 

The percentage unit of measure represents the elongation yield as a percentage of the original length of the material. For example, if a metal specimen stretches 10% before breaking, it has elongated by 10% of its original length. 

On the other hand, millimeters are used to measure the actual physical elongation of a material. This unit of measure provides a more tangible representation of the deformation a material undergoes before reaching its breaking point. 

Both units of measure have their advantages and are suitable for different applications. The choice between percentage and millimeters depends on the material type, testing specifications, and industry standards. 

 

BL0141-Yield Elogation-Inline 1

Data and Testing Method for Measuring 

When determining a material's elongation yield, reliable data and thorough testing methods are essential to ensure accurate measurements and a deeper understanding of how a material will perform under various conditions. The data obtained during material testing provides valuable insights into the behavior of a material and its elongation yield. It includes measurements such as strain and stress, which calculate values. 

  • Strain refers to the deformation experienced by a material when subjected to external forces. It is measured as the change in length divided by the original length. 
  • Stress is the force applied per unit area and is assessed by dividing the applied force by the original cross-sectional area. 

By analyzing the relationship between stress and strain, engineers can identify the point at which the material starts deforming permanently, known as the elongation yield point.  

Overview of the Different Testing Methods Used

Various testing methods are employed to measure this property, each offering advantages and limitations. Tensile testing, for example, is commonly used to evaluate a material's mechanical properties, including elongation yield. 

In tensile testing, a material sample is subjected to controlled tension until it reaches its elongation yield point. The resulting data helps determine the material's ability to withstand loads and deformations. 

On the other hand, impact testing measures the energy absorbed by a material when it fractures under sudden stresses. This method provides valuable insights into the material's toughness and resistance to sudden impacts. 

Other testing techniques, such as bend and hardness tests, can also provide insights. The bend test involves subjecting a material to bending forces to determine its flexibility and resistance to deformation. On the other hand, the hardness test measures the material's resistance to indentation, indirectly indicating its elastic deformation capabilities. 

Specific standards established by regulatory bodies and industry organizations govern the testing procedures. These standards ensure consistency and comparability of test results across different laboratories and manufacturers. 

Importance in Material Selection and Design 

Engineers and designers can make informed decisions regarding coating material by considering the elongation yield. They can determine the material's capacity to stretch and deform before reaching its breaking point, safeguarding the reliability of the end product.  

Moreover, understanding the elongation yield can also help optimize designs, reduce material waste, and enhance overall efficiency. Engineers can create designs that balance strength, flexibility, and cost-effectiveness by accurately predicting the coating material's behavior based on elongation yield values.  

Electronic product reliability hinges on protective coating durability. If a coating breaks in any way, it could open the door to corrosives, chemicals, and other contaminants that could cause electronics to stop working. Therefore, understanding the elongation yield value is vital in ensuring electronic products' safety, durability, and performance in real-world applications. If you need help identifying the best coating material for your application, please contact our Applications engineers for a DFM consult. Alternatively, you can learn more about our coating protection capabilities, including Young's modulus, elongation at break, and tensile strength at yield.  

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ADAS Design and Validation for the Real World - Automotive Coatings

June 15, 2023 / by Mallory McGuinness-Hickey posted in Parylene, Coating Properties, Thin Film Applications

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Advanced driver assistance systems (ADAS) continue to expand in features and functionalities. Standard offerings may include adaptive cruise control, park assist, blind-spot detection, lane departure, RADAR, emergency braking, tire pressure monitoring, and LiDAR systems.
 

When consumers purchase a vehicle with ADAS safety features, they believe they have a layer of protection to be entirely relied on. In reality, though, without a methodical, effective ADAS component design that accounts for real-life situations, these features are no more than crutches.

In addition to the ethical argument that safety should be an underlying principle of ADAS design, liability concerns create a business case for ADAS components that dependably function in the typical automotive service environment.

As ADAS designers evaluate the risk of harm, they may ask about the probability of exposure to an element or situation that could cause failure. They may ascertain how severe the resulting damage may be and determine how controllable the issue is if it should occur.

The risk of harm is high in instances such as premature ADAS component failure due to harsh environments. ADAS PCBAs and components will inevitably encounter corrosive elements, humidity, thermal shock, water ingress, and other environmental factors that compromise electronics. If this ADAS component should fail as a result, consumers relying on a safety feature could incur severe damage and liability, and in terms of controllability, there is not much that can be done upon critical component failure.

ADAS component reliability through harsh environments is a high-risk issue. Therefore, design engineers must prioritize safeguarding ADAS components from failing in these circumstances and verifying their safety in real-life situations. Testing and validation can become problematic when legacy methods such as gaskets and seals bolster ADAS reliability.

 

ADAS features in harsh environments

 

Possible Issues with ADAS Testing Protocols and Traditional Reliability Methods

Issues with ADAS reliability testing protocols may include:

● Testing must confirm that a system will handle situations that can be predicted and that ADAS will reliably work under unknown circumstances.
● Proper validation and verification can entail testing many conditions, particularly as vehicle design shifts towards fully autonomous vehicles.
● Testing for scenarios on a test track may be impractical when methods such as seals and gaskets are used for ADAS reliability.

For example, to test that a seal will continue to prevent ingress while exposed to vibration, you might have to wait for weather conditions to occur naturally, including snow, rain, or humidity. Although you can use equipment to mimic these weather conditions, this will add to testing complexity.

It's Possible to Simplify ADAS Reliability

As noted, seals and gaskets can become dislodged in many situations, which would have to be recreated and accounted for to validate and verify ADAS component reliability if they are the primary protection method. This unpredictability raises complications during the design and validation process.

Furthermore, as more features are built into vehicles, more components will need to fit in. The bulk of seals, potting, and traditional conformal coatings can lead to more design challenges. These conventional methods can also complicate lightweighting efforts as they add unnecessary weight.

HZO’s proven, trusted Parylene coatings solve these testing and design challenges. These conformal coatings come in several types, including Parylene N, Parylene F (VT-4), and Parylene C, demonstrating excellent performance in mission-critical applications for decades, in part due to uniform coverage, barrier properties, and less stress on mechanical structures.

 

HZO Coatings for Automotive Corrosion Protection

We’ve proven that our coatings can deliver as much – or more – flexibility, fungus resistance, flammability, dielectric withstanding voltage, thermal shock, moisture, and insulation resistance at a fraction of the mass of conventional coatings, passing the IPC CC-830C test at 50% of the film thinness. Unlike seals and gaskets, Parylene does not stop providing protection when exposed to unpredictable situations, such as drops and falls. The coating is well studied and, when appropriately applied by engineers who understand the parameters of an application, will withstand the lifecycle of the product it is enabling.

 

Class Type Specimen – Average Coating Thickness [μm]
    1 2 3 4
XY Parylene N 25 25 23 23
XY Parylene C 31 30 30 32
XY Parylene F 46 36 43 29
AR/UR Acrylic 73 73 69 72
SR Silicone 102 99 114 154
AR/UR Acrylated Polyurethane 91 91 107 107

 

Below, you can see how our coatings performed in automotive validation tests.

Contents Requirements Test Results
Operations Test Operate for 24 hours at 23 Degrees C Operate for 24 hours at 23 Degrees C
Coating Property No Pinhole and Uncoated Area No pin hole and uncoated area
Coating thickness 225±3 [μm]
Electrical Test Dielectric withstanding voltage: Over 1.5 [kV]
Insulation resistance: Over 10 [GΩ]
IPC-B-25A standard test board pattern Dv
Over 1.5 [Kv]
Over 10 [GΩ]
Corrosion Test Salt spray (35 °C, NACI, 96 hours):
No corrosion on chip leads
No corrosion on chip leads

 

 

Enhanced Component Reliability and Increased Resistance to Fluids and Oils

 

The automotive operating environment includes exposure to chemicals such as oil, antifreeze, standing water, and cleaning fluids. HZO Parylene coatings offer dependable protection for various leak, environmental, splash, and submersion test requirements.

 

Protection Characteristics Unprotected PCB Mechanical Seal Silicone/Acrylic Coatings Parylene Coating
Protection Barrier None Good, but can be compromised with drops & temperature. Good, but can be thick & porous depending on the application. Excellent. Can peel if not properly applied.
Hydrophobic No No Yes Partial
Thickness N.A. Millimeters μm – Millimeters 2μm – 50μm
Protection Against Water Poor Good – Ingress Poor – Penetration Good Excellent
Salt/Chemical Protection Poor Poor Varies Excellent
Durability Low Varies Varies High
Submersion Test Time to Failure Seconds (IP Rating N.A.) Varies Varies Days to Weeks (IPX7 – IPX8)

 

 

When used as a redundant solution along with legacy methods, our coatings can provide more robust, reliable protection and the ability to reduce sealing, thereby minimizing spacing and weight issues. As the visual below indicates, a mechanical seal can easily be breached. With HZO’s Parylene protection, moisture ingress is not an issue.

 

 

Contact HZO for Automotive Component Coatings

 

If you are interested in Parylene and would like to speak to our industry-leading applications engineering team, please reach out with a message or fill out a quote form to understand your application needs and provide a tailored solution.

 
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Parylene Conformal Coatings - Parylene Conformality Explained

June 6, 2023 / by Mallory McGuinness-Hickey posted in Parylene, Coating Properties

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Parylene (p-polyxylylene) conformal coatings are unique due to their capacity to be polymerized and deposited by the chemical vapor deposition (CVD) method onto surfaces near room temperature. As a result of this process, pinhole-free, high-purity, extremely thin coatings are formed out of dimer materials.

Regarding conforming to complex or unusual surfaces, Parylene is one of the best polymer coatings for moisture resistance. This attribute and the fact that Parylene is a stable chemical compound that creates an excellent barrier make it the optimal choice where resilient electronic products are a mandate. But why is Parylene coating conformal?

Download HZO’s Parylene datasheet to learn more about Parylene’s properties

 

Why is Parylene Coating Conformal?

Liquid coatings with application methods such as dipping, brushing, or spraying may cause the coatings to exhibit meniscus forces or pull away from edges, which does not occur with Paylene deposition. With CVD, the coating penetrates around and beneath closely spaced components with consistent, uniform buildup, allowing for substantial physical and electrical protection with a substantially thinner layer than conventional coatings.

 

Parylene Deposition Process

Thus, the Parylene coating process explains why Parylene is so conformal. You can read an in-depth description of the CVD process versus PECVD in our blog on the subject; below are some general benefits of CVD:

Download a visual explanation of the process

 

  • CVD produces coatings with complete coverage even around and beneath closely spaced chips and wires.
  • CVD deposits Parylene molecule by molecule onto substrates with precision and control.
  • The Parylene deposition process requires no catalyst, hardener, or heat curing.
  • Polymerization does not release harmful by-products, as with other conformal coatings.

Chemical vapor deposition process

 

When Parylene polymers are deposited from the vapor phase with the CVD process, all sides of a component are impinged by the gaseous monomer and uniformly coated. This feature of the process is responsible for why Parylene coating is conformal.

 

Importance of Conformality and Uniformity

Truly conformal coverage occurs when a film precisely follows the coated component’s geometry. Conformality allows for the optimization of surface properties regardless of the shape of the part and ensures that microdevice properties such as conductance do not vary due to significant variations in thickness. Uniform thickness is critical to prevent proper reinforcement against degradation and wear.

 

Parylene Conformality Compared to Liquid Coatings

 

Parylene conformality

 

Along with performance concerns, achieving uniformity improves production factors such as yield rates and repeatability. With the chemical vapor deposition process, engineers have confidence that there will not be thickness fluctuations from product to product and that specs are being met. By ensuring optimum coating deposition performance is met, you can lower your total cost of ownership by keeping your repeatability and yield on target.

 

Parylene Conformal Coating Service with HZO

However, although a process may achieve repeatable, uniform thickness distributions, this does not mean it is viable for your company – uptime and upfront costs must also be considered. Parylene has traditionally only been used for mission-critical applications such as medical products. HZO, a turnkey CVD process provider, has made Parylene and its application feasible for most industries for years. Our engineers have crafted capital coating equipment that addresses upfront cost concerns and makes Parylene scalable. If you are interested in the powerful barrier properties of Parylene films and the benefits of its vacuum deposition process, reach out today to speak to one of our engineers.

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Parylene Chemical Resistance Properties - Overview

January 21, 2022 / by Mallory McGuinness-Hickey posted in Parylene, Protection Capabilities, Coating Properties

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Choosing a conformal coating can be a complex decision that entails understanding the environment your electronic products will be operating in and taking stock of the threats to reliability associated with that environment. Will the coating need to be biocompatible? Transparent? How thick should the coating be?  

Considerations may include the operational temperature range for components and integrated circuits – will the coating you choose maintain performance throughout this range? Will your product be exposed to high levels of corrosives, humidity, or even immersion, requiring a coating with strong barrier properties? Will the environment entail exposure to various chemicals? If so, Parylene’s superior chemical resistance properties may present an ideal solution for the medical and automotive industries.

Learn more about what Parylene is used for 

 

Parylene Coating Chemical Resistance

Chemically inert Parylene conformal coatings exhibit exceptional resistance to solvents at room temperature, maintaining this property to 150° C. This resistance prevents erosion, delamination, and other minimizations of coating effectiveness, ensuring dependable performance. Additionally, Parylene coatings are highly resistant to inorganic reagents, including alkalis and strong acids.

Download HZO’s Parylene datasheet

 

Parylene coating has excellent chemical resistance to solvents and reagents, including those listed below:

Acids, Bases, Corrosives
Hydrochloric acid, 10%
Sulfuric acid, 10%
Nitric acid, 10%
Hydrofluoric acid, 10%
Sodium hydroxide solution, 10%
Ammonium hydroxide solution, 10%
Hydrogen peroxide in water (H2O2)

 

Watch Dr. Sean Clancy expand on Parylene chemical resistance in his webinar

 

Organic Solvents
n-Octane
Toluene
Chlorobenzene
Pyridine
2-Propanol (IPA)
Acetone

The exceptional chemical resistance of Parylene is one of the many beneficial properties that sustain component performance for the length of its expected lifecycle.

 

Parylene C Chemical Resistance

Parylene comes in various types, including Parylene N, C, and F (VT-4), and each type has unique properties, ensuring an appropriate Parylene for every project. Parylene C coatings specifically survive exposure to the corrosive liquids and solids mentioned above and much more. Parylene C has excellent chemical resistance to most solvents and reagents used in processing electronics and other products, including (dilute / ~10 % concentration) acids, bases, and organic solvents, such as isopropyl alcohol.

Understand how chemical resistance influences Parylene removal processes

 

Why is Parylene Chemical Resistance so High?

Parylene’s exceptional chemical resistance is partially due to the unique vacuum deposition method used to apply the coatings, chemical vapor deposition (CVD). In this vapor phase coating process, the polymer chains pack tightly against one another, making Parylene resistant to chemicals passing through the coating and reacting with the film.

Compared to liquid-derived and assembled monolayers, the chemically stronger film consistency is the source of Parylene’s chemical/solvent resistance.

 

Parylene Chemical Reaction

Typical Parylene deposition process, illustrated with Parylene N

 

Download our infographic for an illustrated guide to CVD

If you would like to learn more about Parylene coatings, please visit our Parylene page or explore one of our webinars for an in-depth discussion about Parylene delivered by one of our engineers. If you have decided Parylene is a strong choice for your application, please contact our applications engineering team today for a no-pressure consultation and understand our unique manufacturing advantages that drive down Parylene pricing

Read more about the advantages of working with HZO, including scalable Parylene coating equipment and Parylene masking automation.

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Parylene Biocompatibility Properties

January 7, 2022 / by Mallory McGuinness-Hickey posted in Parylene, Coating Properties

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As a long-proven biocompatible material, Parylene conforms to ISO-10993 and is USP Class VI implantable material. Its properties make it ideal for biological and medical applications, with additional benefits that make it a natural choice for healthcare applications. Learn more about Parylene biocompatibility and other benefits the coatings provide for medical devices.

Parylene Biocompatibility

Parylene comes in various types, including Parylene C, F (AF-4), and Parylene N, and the material has long been used as a protective medical device coating. A biocompatible material will not negatively interact with living tissue. Additionally, it is physiologically non-reactive and isn’t toxic. Parylene is chemically inert, so it can survive exposure to chemicals in and on the human body (such as implantable devices) without reacting with these chemicals.

Due to Parylene’s chemistry and structure, it is biocompatible and meets the United States Pharmacopeia’s (USP) highest standards for biocompatibility certification, Class VI standard. Parylene has passed the USP’s stringent testing process described here and has a proven track record of reliable performance in the medical device industry,

Learn more about other ways Parylene is used

 

Download the HZO Parylene datasheet

 

Benefits of Parylene for Medical Applications

 

In addition to chemical biocompatibility, Parylene conformal coating has many other properties that add value to medical devices. As a low-friction polymer coating, Parylene is a dry lubricant and allows easy sliding. Because increased friction can make a medical procedure more painful and timely, this slickness is an essential benefit for medical implants.

With a mission-critical device such as an implant, long-lasting protection against enzymes, bodily fluids, lipids, and proteins is paramount. Parylene can last for decades and has exceptional barrier properties that lead to superior corrosion resistance, excellent chemical resistance, and robust protection against liquid ingress.

Parylene is odorless and transparent, minimizing irritation, and does not require catalysts, initiators, or curing to be deposited, avoiding impurities that could disrupt its unique benefits. It also maintains protection throughout a wide temperature range

With precise control, Parylene thickness is minimal – 50% of traditional conformal coatings, with pinhole-free coatings that exhibit high dielectric strength.

 

Chemical Vapor Deposition Process

Parylene’s vapor-based deposition process creates a truly conformal, even coating desirable for applications where reliability is a priority. The highly repeatable process generates consistent results and minimizes coating defects. Several CVD services are available, including purchasing CVD equipment for sale. However, without the help of dedicated experts, endeavoring to coat your devices with Parylene can be a timely, cost-consuming process. With improper application, Parylene removal may even be necessary. 

 

Learn more about Parylene pricing

 

hzo-parylene-process-diagram-02

Illustration of the CVD Process

 

Read More about the CVD process

 

HZO Medical Coatings

As a Parylene coating company, HZO focuses on more than just producing dependable, consistent coatings. We aim to simplify the coating process with a turnkey solution, several business models, techniques,  Parylene masking automation, and Parylene coating equipment to reduce costs and make the CVD process scalable.

These benefits allow us to extend the scope of Parylene for medical devices to connected devices worn on the body, such as smartwatches, continuous glucose monitors, activity trackers, and hearing aids. With our engineers’ domain experience, we specialize in coating for the Internet of Medical Things. We believe in Parylene’s capacity to improve these critical devices that ordinarily would not be candidates for coating due to cost and scalability concerns.

If you want to speak to a team member about medical coatings, please contact us today for a consultation.

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Parylene N Properties Explained Datasheet PDF Download

December 10, 2021 / by Mallory McGuinness-Hickey posted in Parylene, Coating Properties

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Parylene is the generic name for poly-para-xylylenes. These conformal coatings come in several varieties, including Parylene C, Parylene F (VT-4), and Parylene N. Parylene properties provide superior barrier protection in the form of thin, pinhole-free coatings applied to components and devices to sustain product life and bolster reliability. Parylene is biocompatible and complies with REACH, RoHS, and Prop 65.

Learn more about what Parylene is used for

 

Parylene N Properties

Parylene N has the highest dielectric strength of the Parylenes, has a melting point of 420°C (or 788°F), and is a commercially available halogen-free Parylene. To see the properties of Parylene N, you can view the HZO Parylene datasheet below, under the column of HZO Zero™, our Parylene N offering, and read a short description of notable Parylene properties. (For reference, HZO Guardian Plus™ is our Parylene C coating solution, ideal for corrosion resistance).

You can also download the datasheet:


Parylene Mechanical and Physical Properties

 

Parylene has a relatively high yield and tensile strength compared to other polymer coatings, with substantial wear resistance. In general, Parylene provides superior mechanical protection.

 

Parylene N Young’s Modulus

Young’s modulus measures the stiffness of solid material or resistance to elastic deformation. The values for Tensile Strength and Young’s Modulus for Parylene N and C can be found below, as well as for polyester and polyamide.

 

Table 1: Young’s Modulus and Tensile Strength for Parylene C and N and Polyester and Polyamide

Material Young’s Modulus Tensile Strength
Polyester 7.1×105 psi MD 29,000 psi MD
Polymide 3.6×105 psi ~33,500 psi
Parylene C 4.6×105 psi 10,153 psi
Parylene N 3.5×105 psi 6,526 psi

 

 

Parylene Electrical Properties

Parylene is a superior electrical insulator with excellent uniformity, and the pinhole and defect-free coverage help the coatings prevent arcing. Although the insulating properties of the Parylene increase with thickness, they are defined by the fundamental composition of the coating. Each type of Parylene has different properties, and by selecting a specific thickness and type, you can fine-tune electricity-blocking properties.

 

Parylene Dielectric strength

Dielectric strength is the maximum voltage required to produce a dielectric breakdown through the coating material, expressed as Volts per unit thickness. This is an essential property for higher voltage design, as it protects against high voltage from static electricity and arcing.

 

Read more about Parylene’s optical properties

 

Parylene Thermal Properties

Read more about Parylene temperature range

Like all materials, Parylene coatings degrade as the temperature increases but have high melting points. The temperature stability values for the Parylenes are listed in the table below.

Table 2: Parylene Thermal Properties

Parylene Type

Long-Term Temperature Limit (°C)

Duration=~10+ Years

Short-Term Temperature Limit (°C)

Duration=~1 Month

Melting Point Temperature (Tm)
Parylene N 60 96 420
Parylene C 80 115 290

 

Read more about Parylene Removal 

 

Parylene Barrier Properties

Parylene coatings provide an excellent physical barrier protecting the coated components from electrical shorting and external contamination. The coating blocks gases that can lead to corrosion of the coated object and serves as a physical barrier to protect from sources of contamination, including foreign object debris (FOD), dust, airborne salts, and metal filings. Parylene also has exceptional chemical resistance with a chemical barrier layer. 

Gas permeability and water vapor transmission rate (WVTR) are important properties for evaluating corrosion resistance; the lower, the better. The table below illustrates these properties in Parylene and other conformal coating materials.

 

Table 3: Barrier Properties of Conformal Coatings

Polymer Gas Permeability at 25 °C, (cc·mm)/(m2·day·atm) WVTR,(g·mm)/(m2·day)
N2 O2 CO2 H2 H2S SO2 CI2
Parylene C 0.4 2.8 3.0 43.3 5.1 4.3 0.1 0.08
Parylene N 3.0 15.4 84.3 212.6 313 745 29.2 0.59
Parylene F (VT-4) 16.7 0.28
Epoxy (ER) 1.6 4 3.1 43.3 0.94
Polyurethane (UR) 31.5 78.7 1,181 0.93
Silicone (SR) 19,685 118,110 17,710

 

Watch Dr. Clancy’s webinar on proven methods of corrosion resistance

About HZO

HZO is focused on increasing coating efficiency and driving down Parylene costs. We provide scalable Parylene equipment and automated Parylene masking to save time and labor within our turnkey solution. Contact us today if you are considering Parylene for your application and want to speak to an engineer.

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Parylene C Datasheet (PDF Download) - Properties Explained

August 20, 2021 / by Mallory McGuinness-Hickey posted in Parylene, Coating Properties

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Parylene conformal coatings come in various types, including Parylene C, Parylene N, and Parylene F (VT-4), with decades of trusted performance in critical industries and applications. The coating is often superior in barrier properties, uniform coverage, and performance, with less stress on mechanical structures, as a Parylene datasheet indicates.

Parylene coatings have good optical properties, are comparably thinner than conventional conformal coatings, and add virtually no weight to components and products. Parylene’s coating thickness can pass tests such as IPC CC-830C at 50% of the film thickness of other conformal coating materials.

Parylene coatings are unique in their ability to be polymerized and deposited by chemical vapor deposition (the Parylene coating process) onto components maintained at room temperature. As a result, the coatings are high purity, free of defects and pinholes, and ideal for meeting many electronic product design reliability requirements.

Parylene C is biocompatible, highly resistant to moisture, vapor, and corrosive gasses, and exhibits strong chemical resistance. Because of these strong anti-corrosion properties and a valuable combination of properties for most applications, from medical devices to personal computers. Parylene C is used for most products that need a conformal coating for protection.

Learn more about why Parylene is used

To see the specific properties of Parylene C, you can download HZO’s Parylene datasheet below, under the column of HZO Guardian Plus™, our Parylene C offering. For reference, HZO Guardian Zero™ is our Parylene N coating solution, suitable for halogen-free applications.

Download HZO’s Parylene datasheet.

 

For reference, a short description of each category property in the Parylene datasheet is provided, as well as some descriptions of tests used to acquire data and explanations as to why some data points might be vital for your application.

Parylene Physical and Mechanical Properties

 

Parylene is a crystalline polymer that results in generally high mechanical strength. Compared to other polymer coatings, it has a relatively high tensile and yield strength, with substantial wear resistance. An explanation for some Parylene datasheet properties is below.

 

Parylene C Young’s Modulus

 

Young’s modulus is a mechanical property that measures the stiffness of a solid material. Young’s modulus is the elongation of a material under unit stress when the deformation is elastic.

The image below depicts an example stress-strain curve which shows the change in stress as strain increases and identifies Young’s modulus and Tensile strength

Young’s modulus is the slope of the linear part of the stress-strain curve for a material under tension or compression. In other words, the strain will be proportional to stress. There is no permanent deformation either. The material will behave like a spring and return to its original dimension upon removing load.

Tensile strength is the maximum stress a material can withstand. Meanwhile, Elongation to Break is the ratio between the changed length and the initial length after the breakage of test specimen.

Parylene Young's Modulus

Image Source: https://www.thefabricator.com/thefabricator/article/metalsmaterials/the-differences-between-stiffness-and-strength-in-metal

 

The table below shows values for Young’s Modulus and Tensile Strength for Parylene C and N and polyester and polyamide.

 

Table 1: Young’s Modulus and Tensile Strength for Parylene C and N and Polyester and Polyamide

Material Young’s Modulus Tensile Strength
Polyester 7.1×105 psi MD 29,000 psi MD
Polymide 3.6×105 psi ~33,500 psi
Parylene C 4.6×105 psi 10,153 psi
Parylene N 3.5×105 psi 6,526 psi

 

Parylene C Electrical Properties

 

Parylene doesn’t conduct electricity, an essential trait for a film that coats and separates conductive areas on electronics. As the Parylene datasheet indicates, it is a superior electrical insulator (dielectric) coating since it coats every surface on a product with uniform thickness. Although conformal coatings aren’t meant to be used as the primary means of electrical insulation, they can isolate electrical ground from active traces and supplement other insulation forms. The lack of pinholes and other point defects helps Parylene prevent arcing.

A coating with variable thicknesses on an electronics assembly running at high voltage may have a greater risk of failure if the device operates near the dielectric breakdown voltage of the coating. The coating undergoes a complete failure at the breakdown voltage, and any insulative properties are left negligible or lost entirely.

An example of how Parylene deposits is depicted below:

Parylene Deposition

Courtesy of CALCE, University of Maryland

 

Though defined by its fundamental composition, the insulating properties of a Parylene coating increase with thickness. By selecting a specific Parylene thickness, you can fine-tune electricity-blocking properties. Since each Parylene type has different dielectric properties, there’s a suitable parylene for virtually every application.

 

Parylene Dissipation Factor

The dissipation factor is the reciprocal ratio between the insulating material’s capacitive reactance to its resistance (Equivalent Series Resistance or ESR) at a specified frequency.

This property measures electrical energy lost and absorbed (power dissipation) when an electrical current is applied to an insulating material. Much of the absorbed energy is dissipated as heat—the lower the dissipation factor, the more efficient the insulator system. Dissipation factor is an essential property because it can be used to maximize power delivery.

 

Parylene Dielectric Strength

Dielectric strength is defined as the maximum voltage required to produce a dielectric breakdown through the material and is expressed as Volts per unit thickness. The image below shows that the original dielectric material as an insulator becomes a conductor because the dielectric material passes the maximum voltage and produces a dielectric breakdown.

Parylene Dielectric Strength


Dielectric strength is important for higher voltage design because it prevents arcing and protects against high voltage from static electricity. Please refer to the Parylene datasheet to see the values for this property.

 

Learn about Parylene removal considerations.

 

Parylene C Dielectric Constant

Dielectric constant is the ratio of the permittivity of a substance to the permittivity of free space.

 

Dielectric Constant (k) = ε / ε0

Parylene Dielectric Constant

A sample is placed between two metallic plates, and capacitance is measured to obtain these values. A second run is measured without the specimen between the two electrodes. The dielectric constant is the ratio of these two values, and a low dielectric constant is essential for rapid signal propagation.

 

Parylene Thermal Properties

Parylene coatings have temperature limits that, when reached, shorten the coating’s usefulness. You must know your expectations and/or specifications for the product’s end-use environment to mitigate risks associated with high-temperature applications. The temperature stability values for the parylenes are collected in the table below and are based on industry literature.

 

Table 2: Parylene Thermal Properties

Parylene Type Long-Term Temperature Limit (°C)

 

Duration=~10+ Years

Short-Term Temperature Limit (°C)

 

Duration=~1 Month

Melting Point Temperature (Tm)
Parylene N 60 96 420
Parylene C 80 115 290

 

Fortunately, the Parylene C melting temperature is high, at 290 °C. Parylene N maintains performance through even more extreme temperatures.

Read more about Parylene temperature range

 

Parylene Barrier Properties

Parylenes are hydrophobic, ultrathin, lightweight, and highly conformal, wrapping around every edge available, where the coating deposits the same thickness around the components they coat. The vapor phase coating process leads to pinhole-free coatings that are also defect-free. In addition, the coatings trap and immobilize any particles that may be present on substrates.

The polymer chains pack tightly against one another, making Parylene resistant to chemicals passing through the coating and reacting with the coating itself. Parylene is impervious to moisture and insoluble in chemicals found in most end-user and industrial environments. The coating also does a good job of blocking gases that can lead to corrosion of the coated object.

The Parylenes provide an excellent physical barrier that protects the underlying objects, especially electronics, from external contamination and electrical shorting. As a physical barrier, Parylene protects from various types of problematic contamination, such as dust, foreign object debris (FOD), metal filings, and airborne salts.

Parylene C has the best barrier properties, as indicated on the Parylene datasheet, including preventing gas and water vapor penetration. The table below compares the Gas Permeability and WVTR of Parylene with other conformal coating materials.

Table 3: Barrier Properties of Conformal Coatings

Polymer Gas Permeability at 25 °C, (cc·mm)/(m2·day·atm) WVTR,(g·mm)/(m2·day)
N2 O2 CO2 H2 H2S SO2 CI2
Parylene C 0.4 2.8 3.0 43.3 5.1 4.3 0.1 0.08
Parylene N 3.0 15.4 84.3 212.6 313 745 29.2 0.59
Parylene F (VT-4) 16.7 0.28
Epoxy (ER) 1.6 4 3.1 43.3 0.94
Polyurethane (UR) 31.5 78.7 1,181 0.93
Silicone (SR) 19,685 118,110 17,710
 
Ref.: Licari, James J. Coating Materials for Electronic Applications – Polymers, Processes, Reliability, Testing. William Andrew Publishing, 2003 and various companies’ literature.

 

Parylene C also performs well when immersed in solutions of sodium chloride salt in water. The following table shows Parylene C’s performance compared to examples of epoxy, polyurethane, silicone, and Teflon™ coatings.

Table 4: Resistance of Different Polymers to 0.9% Saline Solution

Polymer Coating Method Layer Thickness (microns) Time Until Total Breakdown
Parylene C 60 25 > 30 d
Epoxy (ER) 80 100 ± 25 6 h
Polyurethane (UR) Dip Coating 100 ± 12.5 6 h
Silicone (SR) Dip Coating 75 ± 12.5 58 hr
Teflon Spraying 75 6 h
 
Ref.: Mordelt, G., Heim, P. High-Tech-Beschichtung der Zukunft, Metalloberfläche 52(5), 368 − 371 (1998).

 

In general, Parylene C performs extremely well as a barrier to corrosion due to the coating’s ability to minimize the influence of the factors that affect coating lifetime and performance, including the following:

  • Oxygen permeability − low oxygen permeability for a polymer coating
  • Water vapor permeability − very low WVTR for a polymer coating
  • Liquid water uptake − Parylene C absorbs very little water
  • Ionic permeability − salts have a difficult time passing through the coating
  • Coating porosity − at a thickness of just 5 to 8 microns, Parylene C forms a pinhole/pore-free coating

Watch Dr. Clancy’s webinar on proven methods of corrosion resistance

 

About HZO

HZO is a Parylene services provider focusing on driving down associated costs and increasing coating efficiency for Parylene’s solvent-free deposition method. We have built proprietary cubed Parylene chambers that can house more substrates than any other Parylene company. Our chambers are large in size, but the cubed shape allows for high loading density, increasing throughput, and scaling for high-volume applications.

We have also built equipment to automate Parylene masking and demasking to cut costs, save on labor, and decrease the risk of quality issues due to manually doing these processes.

To learn about Parylene pricing for your next project, contact us today. To learn about our proven track record, read our case studies.

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How to Choose a Nanocoating Material

April 28, 2021 / by Mallory McGuinness-Hickey posted in Coating Properties, PECVD Coatings

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As engineers, it is our job to bring products to life and ensure they operate as expected until the end of the product life cycle. Therefore, a large part of our job is to prevent premature failure by providing electronic products with appropriate protection from environmental threats that can cause an immediate or unplanned shutdown. To do this, we must evaluate protective solutions and sometimes think outside the box. We may need to rethink protection in a landscape punctuated by miniaturization, ruggedization, and sustainability concerns. Nanocoating technology can often address these needs better than current methods like gasketing, protecting products from liquid damage and its subsequent harm to business reputation.

 

Hydrophobic Nanocoatings to Improve Performance

Protective nanocoatings are thin films of coating material measured in thicknesses of nanometers applied directly to the surface of PCBAs and other components or materials. With nanocoatings, product design teams can meet many objectives, including material hydrophobicity (water-repellent) due to the low surface energy of the coating. This may be important for a wide range of applications, like increasing the water resistance of electronics, helping your down sleeping bag stay dry, or allowing water to bead off car windshields more easily. Nanocoatings' other protective capabilities include corrosion protection, hardness, or, sometimes, oleophobic properties (oil repellent).

To effectively apply hydrophobic coatings of this caliber, vacuum deposition is required to ensure the quality and consistency of the application. Plasma-enhanced chemical vapor deposition (PECVD) is a popular nanocoating process because it is flexible, controllable, and appropriate for various applications. PECVD utilizes plasma, a high-energy, gaseous state that enables material to deposit onto substrates. The process parameters vary tremendously, including power, plasma type, temperature, deposition time, pressure, gas flows, and gas composition. Adjustments to these parameters make it possible to produce highly-performing thin films tailored to your protection requirements. Due to the versatility of the PECVD process, a wide range of materials can be deposited to help engineer a specific coating solution.

The material you ultimately use for deposition is closely related to coating performance, so it is essential to select carefully. The criticality of material choice begs the question: how do you choose the best nanocoating material for your project?

 

Download our HZO Nanocoating Datasheet

 

 

Choosing the Right Nanocoating Material

 

There are halogenated materials (fluorocarbons and chlorocarbons) and halogen-free (silicones, hydrocarbons, metal oxides, and metal nitrides). Ultimately, performance requirements and sustainability concerns will determine which is preferable.

Halogenated Materials
Halogenated material processes produce coatings with high hydrophobicity or strong etching capabilities. Halogen-free material processes, such as silicones and metal oxides, deposit coatings that serve as strong water barriers, offering strong performance.

Halogen-Free Materials
Sometimes non-halogenated materials are preferable for environmental reasons. If you are considering halogen-free materials, the choice does not end there. You’ll have to consider other requirements. For example, metal oxides may provide more substantial protection, but a hydrocarbon coating may provide acceptable performance and is generally easier to handle than other materials.

 

Understanding the Performance Requirements

 

While understanding if you prefer halogenated or halogen-free materials will be a critical part of your decision, you must thoroughly understand your product’s performance requirements to choose which material to use. Hydrophobic, hydrophilic, and corrosion resistance properties will determine whether a fluorocarbon, silicone, metal oxide or another material is preferred.

 
hydrophobic nanocoating

 

After You Have Chosen a Nanocoating Material

After determining what material type to use, the selected material will determine the precursor (materials that chemically react and/or decompose on the substrate’s surface) and plasma parameters to use. Different gas or liquid precursors result in different coatings. For example, methane may be used as a simple hydrocarbon coating, carbon tetrafluoride for a fluorocarbon, or hexamethyl dioxolane for silicone.

Even after determining the precursor, the flow rates of that liquid or gas and other parameters can dramatically affect the final coating properties. For example, adding oxygen, nitrogen, or argon can completely change the results. Argon is inert in the overall reaction, but it may change the reaction mechanism, which is the sequence of steps that make up the overall reaction. The mechanism affects what film is deposited. Adding oxygen may create oxides, and nitrogen may form nitrides, which add to the film’s hydrophilic properties. Meanwhile, different flows of the same gases may result in different coating properties. Gas flows may range from a few sccm (standard cubic centimeters per minute) to 10,000 sccm or more. This flow rate difference may change the reaction mechanism, altering what is deposited.

 

Seeking Technical Expertise

As you can see, with PECVD, there are many options where significant experience and development will be required to understand which materials are best. If you are interested in PECVD coating technology and want help getting started, please reach out today for a consultation. 

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NEMA vs IP Ratings Explained

April 14, 2021 / by Mallory McGuinness-Hickey posted in Protection Capabilities, Coating Properties

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Once upon a time, computers only sat perched on desktops, but that is no longer the case. Deployed in harsh industrial, medical, automotive, and consumer household environments, electronics must now withstand exposure to water and liquids ranging from “condensing” moisture to total submersion that requires waterproof design. They must reliably operate despite threats posed by humidity, corrosives, and other outdoor contaminants.
 
 

To assure your customers that your electronic products can dependably withstand these challenges, you must meet reliability standards, such as Ingress Protection (IP) Standards or National Electrical Manufacturers Association (NEMA) Protection Ratings. These systems classify an enclosure’s protection level from harmful elements by defining protection posed by solids and liquid ingress. It is crucial to select the correct standard to assure your clientele that the product you offer will be reliable in specific environments. This choice can be complicated because comparing NEMA vs IP rating systems is impossible, but alternative solutions may eliminate the need to select one or the other.

 

View our webinar to see if it’s time to rethink enclosures.
 
 

IP vs. NEMA-Rated Enclosures

Any comparison of Ingress Protection ratings and NEMA standards will only be approximate. An IP Rating only considers enclosure protection against water ingress and solid foreign objects. Meanwhile, the NEMA rating system, often used as an industrial enclosure rating system, considers these factors, as well as other hazards such as corrosion. So, while you can say a NEMA type is equivalent to an IP rating, it is impossible to say that an IP rating equals a NEMA rating. Additionally, the two systems use different test parameters to define the level of protection, so there is no easy conversion.

 

NEMA Ratings

NEMA electrical enclosure ratings have numeric values, sometimes followed by a letter. Each rating corresponds to the hazards an enclosure must protect its interior and may indicate indoor or outdoor use.

You can explore a quick guide to specific NEMA ratings here.

When choosing a NEMA enclosure type, it’s essential to consider both the environmental hazards the interior needs protection from and the enclosure location to use NEMA ratings appropriately. For example, a NEMA 4 rating is popular because it accommodates outdoor environments and multiple weather types. NEMA rating 4X features watertight seals, corrosion resistance, and protection from dust for more extensive protection.

 

IP Ratings

IP ratings may be designated by two or three numbers corresponding to protection from solids, liquids, and impacts. X replaces the number if a device does not have a specific rating. The first number signifies the object size that the enclosure prevents from entering. The higher the value, the more protection from solid ingress, such as windblown dust.

The next value indicates liquid ingress protection, with digits ranging from zero to eight, with increasing amounts of protection as the numbers increase. Finally, the third value corresponds to the mechanical impact an enclosure can withstand. This value may not be present in some electronic products because most codes do not require its presence.

A short guide to IP specifications can be found here.

 

Read our IP Checklist

 

Rethinking Enclosure Standards

IP or NEMA standards may not be the best indicator for the degree of protection you need. For example, while IP liquid ingress testing works in the lab, it may not perform the same in real life. Chances are that you will still need to demonstrate that your product can meet these standards to meet customer specifications.

Thin-film coatings can be an easy and efficient way to meet both NEMA and IP liquid ingress standards. These polymeric barriers protect from the inside by directly applying components and PCBAs. They are lightweight and thin, helping you eliminate seals and, therefore, excess bulk and weight. The protective coatings also blend into the product so you can offer aesthetically pleasing, ergonomic, and functional products easily. Thin-film coatings can be used in a two-phase approach to protection that is failsafe and can help you save money and time customizing enclosures.

 

HZO Coatings and Relevant Standard Equivalents

NEMA vs IP table comparing HZO coatings to the standard

 

Contact Us

 

HZO offers thin-film coatings to protect your electronic products. We focus on tailored solutions to your protection requirements and can help you exceed liquid standards easily with proven solutions, with no enclosure testing required. Download our datasheets, or send us a message for a consultation.

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Conformal Coating Thermal Conductivity - Prevent Overheating

October 2, 2020 / by Mallory McGuinness-Hickey posted in Protection Capabilities, Coating Properties

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Design engineers have more to worry about these days than ever before. The demand for smaller electronic devices with more capabilities is exponentially growing, causing engineering challenges also to grow. More integrated circuits, resistors, diodes, transistors, and capacitors must be packed into a shrinking space, increasing a device’s susceptibility to overheating due to a reduction in thermal flow.

Done improperly, poor design and engineering can directly cause overheating, leading to decreased reliability, premature failure, and damages resulting in avoidable cost and brand damage. All electronic devices and circuitry generate excess heat as current flows through a circuit, causing the need for better thermal management. Each component has a rated maximum operating temperature, and heat dissipation is critical to avoid overheating and exceeding the temperature limit.

 

How is Heat Removed from Electronics?

Heat must be dissipated to ensure that devices remain safe, reliable, and perform as intended. This process can happen through many different methods, including:

  1. Convection: a transference of heat through moving fluids
  2. Conduction: a process in which heat dissipates throughout a material
  3. Radiation: allowing heat to dissipate through electromagnetic waves

 

Mechanism Definition heat dissipation path percentage of heat

Conduction

Heat transfer between objects that are in physical contact. External pins of component to the printed wiring board. Then, convection into the atmosphere. ~80%
Convection Heat transfer between an object and its environment due to fluid motion (liquid or gas). Top surface and sides of the package into the atmosphere. ~10%
Radiation Heat transfer through the emission of electromagnetic waves. Radiative heat from the package surface area. Low contribution to total heat dissipation unless package surface area is relatively large. ~10%

 

*Estimates For A 352-pin BGA Type Component

 

Conformal Coating Thermal Conductivity

In many electronic designs, ~80% of heat energy is dissipated through conduction to some form of a heat sink designed to dissipate heat by spreading it over a larger surface area, removing the heat to the atmosphere through convection.

The heat flow between a component and ambient air is modeled as a series of resistances to heat flow. The sum of these is the total thermal resistance (°C/W). The goal here is high surface area in contact with air and a material with high thermal conductivity.

That being said, common heat sink materials are materials with high thermal conductivities:

Material thermal conductivity (W/mk)
Aluminum Alloy 1050 229
Aluminum Alloy 6061 166
Aluminum Alloy 6063 201
Copper 400

 

 

 
 

Conformal Coatings and Heat Dissipation: Considerable Challenges

 

Overheating is not the only reliability challenge for design engineers. Environmental constituents such as corrosives threaten reliable printed circuit board (PCB) performance. Engineers increasingly incorporate conformal coatings into their designs as devices shrink instead of enclosures and seals, which can consume precious real estate in miniaturized devices.

These polymeric films are used as a barrier layer to contaminants, corrosives, solvents, and solid materials commonly found in operating environments. Materials such as acrylics, silicones, epoxies, polyurethanes, and Parylene can be applied to substrates, enhancing electronic reliability in the harsh environments that next-generation electronics face today.

These protective coatings can outperform seals and enclosures when it comes to reliability. The electrically insulative properties of conformal coatings, such as dielectric strength, prove useful here; spacing between conductors can also be reduced, allowing for the integration of more electronic components.

Learn more about the dielectric constant of insulator materials in our blog.

Unfortunately, traditional conformal coatings have low thermal conductivity, generally between 0.125 and 0.335 in W/mK. As the chart above indicates, these values are hundreds to thousands of times lower than those for ceramics or metals. As such, conformal coatings are good heat barriers, and when used in thick layers, they can interfere with the heat transfer path, impeding heat dissipation.

Although formulating a coating with metal or inorganic fillers can increase thermal conductivity, the compositions containing metal fillers will also become electrically conductive, meaning they are no longer suitable for electronic applications requiring electrical isolation.

This presents a paradox to design engineers. There is a need for highly thermally conductive polymers capable of transferring heat that are also electrically insulative, particularly for high-density microelectronics.

For conformal coatings, if thermal conductance is a requirement, design engineers can take either or both of two approaches:

  • Employing a coating filled with as much thermally conductive filler as possible.
  • Integrating the thinnest coating possible, as thermal conduction is inversely proportional to thickness.

Although using a filler can lead to a gain in thermal conductivity, ironically, the benefit is offset by a thicker coating that is challenging to apply. The coating’s electrically insulating properties may be affected as well. 

 

Read more about waterproof design.

 

Parylene Conformal Coatings for Heat Dissipation

 

Regarding reliability, you shouldn’t have to choose between bulkier, less reliable barrier protection and susceptibility to overheating. Evaluating conformal coatings for heat dissipation entails several considerations: thermal conductivity, emissivity (the surface of a material’s effectiveness in emitting energy as thermal radiation), film uniformity, adhesion to the substrate, and film thickness.

However, thermal conductivity and film thickness are the most critical parameters for heat dissipation when selecting a conformal coating. This is where Parylene is a distinctive choice.

 

Coating thermal conductivity (W/mk) film thickness (um)
Desired High Low
Parylene N 0.13 2-50
Parylene C 0.08 2-40
Acrylic 0.13-0.25 30-130
Epoxy 0.17-0.21 30-130
Silicone 0.15-0.31 50-210
Urethane 0.21 30-130

 

Other conformal coating materials are typically applied at a thickness range of 50 to 250 microns. Parylene can be applied at a fraction of the thickness, ranging as low as 2 microns. For context, this is less than the width of a strand of human hair.  

 

Parylene Performance at Scale

 

At HZO, we provide Parylene services to industries where device overheating is a serious concern. But when it comes to conformal coatings, Parylene is not just a superior choice for heat dissipation. It exhibits many excellent properties that bolster device reliability, such as chemical resistance and the ability to remain reliable throughout a wide temperature range.

More information on parylene coating costs

Each Parylene type has distinct characteristics, so there is a Parylene for virtually every application. For example, Parylene C provides the best corrosion resistance of all the conformal coating polymers. My colleague, Dr. Sean Clancy, delivered an excellent webinar on Parylene’s corrosion resistance, which I encourage you to view. You can also download HZO’s Parylene datasheet to learn more about Parylene’s beneficial properties.

Something my team is incredibly proud of is our customer service. We have formed meaningful partnerships over the years, providing masking and demasking recommendations, offering DFX guidance, and working with our customers to integrate our coating process into many points of their production.

If you are interested in protection for your project and need to understand the alternatives better or are simply curious to learn how leading OEMs are designing the next generation of mobile, wearable, edge, and general electronic devices, reach out to us today or fill out contact or quote form to get started. We are not simply a job shop but a team of dedicated engineers who understand your design challenges. 

You do not have to settle regarding heat dissipation or electronic protection. Your device is in good hands when you work with HZO.

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IoT - Coating Consistency is Key

September 25, 2020 / by Mallory McGuinness-Hickey posted in Parylene, Coating Process, Coating Properties, Value of Coatings

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IoT sensors aggregate and send data to IoT dashboards, simplifying critical, complex decisions quickly. One key area where this is particularly true is the utilization of sensor data for predictive maintenance, a process that reduces downtime and lowers the total cost of ownership. Myriad other applications incorporate these “smart” sensors too.

Today, IoT sensors are ubiquitous, touching almost every aspect of life. Gas pressure sensors monitor pressure changes in oil, energy, and utility applications. Photoelectric devices (photo sensors) are now common in the consumer electronics vertical. Sensors are responsible for temperature monitoring, a typical use case for warehouse and inventory management, and HVAC systems monitoring.

Accelerometers detect subnormal industrial machine applications, while ultrasonic flow meters are coupled with IoT modules to send data about smart metering to a remote location. Moisture sensors have been critical in recent advances in smart farming, allowing for constant soil health monitoring. In the automotive sector, tunneling magnetoresistive sensors (TMR) are an increasingly popular way to measure mechanical displacement. And Particulate Matter sensors detect pollution in the industrial landscape and smart cities.

 

The chemical vapor deposition (CVD) process used to deposit Parylene conformal coatings can efficiently accommodate these complex surfaces. Parylene’s usefulness is primarily founded upon its ability to cover PCBA configurations with exposed internal surfaces, sharp edges, flat surfaces, points, and crevices with consistent coverage free of voids.

 

HZO PRO750 Parylene Coating Equipment

HZO PRO750 Parylene Coating Equipment

 

The Parylene Deposition Process – Consistent Coverage

Rather than dipping, spraying, or brushing pre-formulated layers onto PCBAs and other components, Parylene’s application method synthesizes the protective film in-process. This deposition system comprises a series of vacuum chambers that produce Parylene vapor, pyrolyze the vapor, then deposit the vapor as a polymer sequentially.

During the CVD process, gaseous Parylene penetrates the layers of a PCBA. Its vaporous consistency surrounds all areas as it builds coating protection along the exterior. The coating layers are substantially thinner than those provided by liquid conformal coating materials, enhancing reliability and functional versatility.

It has repeatedly been demonstrated that CVD is valuable for thin-film deposition on irregular PCBAs. CVD's Conformal layers are exceptionally uniform, even in the nanometer range. Because these coating layers are exceptionally thin, non-uniformity is minimal.

 

Reach out to an Expert 

Choosing Parylene conformal coating services isn’t a failsafe decision, like anything else. Problems can occur with the process and the material. This is particularly true if the wrong Parylene type is used for a coating project while another type could provide better coverage. If you need a consultation to determine if Parylene is the right choice for your project, contact the HZO engineering team today, fill out a quote form, or leave a brief message.

 
 
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Parylene Optical Properties - UV Light Interactions, Refractive Index

September 3, 2020 / by Dr. Sean Clancy posted in Parylene, Protection Capabilities, Coating Properties

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With Parylene, you always have a clear and accurate view due to its optical properties. Although the Parylene deposition process begins with white to off-white dimer powder, the result is a transparent coating that retains clarity and color throughout your product’s lifecycle.

Across myriad industries, Parylene types C, Parylene N, and F are used when optical qualities are critical to product applications. Optical lenses, fiber optic components, electro-optical components, and optical sensors are frequently coated with this thin polymeric film for protection from the environment.

Learn more about what Parylene coating is used for

 

Optical Applications

Parylene has excellent transmission and, conversely, low optical absorption in the visible and near-infrared regions of the electromagnetic spectrum, which ensures desirable performance in these regions.

Parylene’s thin, transparent protection is particularly beneficial for light-emitting devices, as the colors of the emitted light and device efficiency are unaffected. Therefore, Parylene proves useful for optical devices, cameras, and LED lights exposed to challenging outdoor environments.

Read about Parylene masking and Parylene removal

 

Refractive Index

Refractive indices are an important consideration in many optical applications. These describe how much light changes in direction as it passes from one medium into another. Additionally, refractive indices help determine the dispersive power of prisms and the focusing power of lenses.

Specifically, the refractive index is the ratio of the speed of light in a vacuum compared to the speed of light in a material. Parylene N has a refractive index of 1.66, meaning that the speed of light in this Parylene type is 1.66 times slower than light in a vacuum.

Read about Parylene chemical resistance and Parylene biocompatibility.

 

HZO PRO750 Parylene Coating Equipment

With Parylene conformal coatings, you always have a clear and accurate view.

UV Light Interactions

Extended UV exposure in air degrades Parylene N, C, D, and after a more extended period, VT-4. If direct sunlight exposure is limited, the effects of the UV are not as detrimental. Both UV and oxygen must be present to raise any significant issues.

Although VT-4 is better than C and N in this regard, dimer material can cost three to five times more than C. Similarly, AF-4 is much more UV resistant than VT-4, but this dimer can cost up to 20 times more than C, with significantly more limited suppliers and availability.

 

Read Dr. Clancy’s blog posts on Parylene thickness and Parylene temperature range

 

The Big Picture

Apart from the detrimental UV light interactions exhibited with the non-fluorinated types, Parylene films provide excellent optical properties and enhance the reliability of mission-critical applications, such as aerospace, scientific, and telecommunication components and integrated circuits. If your project specifications call for products that can retain color and clarity, Parylene is an excellent option.

Do you need help from an expert in selecting a polymer coating for your next project? We can assist with scalable Parylene coating equipment. Reach out to our team today for a consultation.

 

Understand More About Parylene Coating Cost

 
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Parylene Temperature Range - Extreme Hot & Cold Temperatures

August 27, 2020 / by Dr. Sean Clancy posted in Parylene, Coating Properties

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Do you need product protection that can withstand temperature extremes? Parylene may be a good option if you utilize the correct type.

Learn more about why Parylene is used

 

Parylene in Cold Temperatures

Parylene performs relatively well in cold temperature extremes. As all polymer materials cool, they become less flexible, stiffer, and more susceptible to physical damage.  Most conformal coatings crack when flexed once or twice at these temperatures, while Parylene films can withstand flexing up to six to nine times.

Learn about Parylene chemical resistance and biocompatibility 

 

Parylene Thermal Properties

As temperature increases, materials degrade, and Parylene coatings are no different. Each type has a temperature limit that, when reached, can shorten the life of the coating. As Parylene reaches the end of its lifecycle, it becomes less flexible and more brittle, forming cracks that may allow corrosive ingress, putting your product at risk.

To reduce the risk of coating failures caused by temperature extremes, let your coating provider know what you expect and your project specifications.

Read more about Parylene C and Parylene Type N

 

Melting

The Parylenes’ melting points are very high, above typical solder and other circuit board materials, so melting is not an issue when temperatures increase. However, when certain temperatures are reached, the Parylenes transition from a more ordered/crystalline state to a more amorphous/plastic state. When Parylene is heating or cooling during this transition, it's possible to cause mechanical stress on componentsbut in all practicality, the stress is minimal and rarely affects the product.

 

Learn more about Parylene's pricing considerations

 

a coating engineer looking at parylene under a microscope

 

Cracks

In cases of high temperature, most of the Parylenes undergo oxidation. Exposure to oxygen and heat causes microscopic cracks in most Parylene films, which can become severe enough to cause visible cracks to the naked eye. Once formed, a crack can potentially expose the product to possible corrosion and contamination, which is problematic. Due to their chemical structures, Parylenes N, C, D, and VT-4 are susceptible to cracks under these circumstances. However, Parylene AF-4 can survive much higher temperatures than the other types. When oxygen isn’t present, all of the Parylenes can handle much higher temperatures.

 

Read Dr. Clancy’s other articles on Parylene optical properties and Parylene thickness

 

Color Changes

Sometimes, chemical changes such as oxidation can cause physical changes, as with Parylene. When the film faces extreme exposure to heat, the typically transparent coating takes on a slight yellow hue as it is oxidized. Microcracks may also develop and grow larger. Around the edges of the cracks, the coating curls upwards with the appearance of dried mud. Additionally, if the product is in motion or the coating is flexed, cracks will quickly become worse.

Most things expand with higher temperatures and shrink with lower temperatures, and Parylene is no different. If the rate of expansion (coefficient of thermal expansion) of the coating and the coated product are similar, it is less likely that cracks will form in the coating.

 

Flammability Best Practices

Conduct flammability testing to comply with industry standards and ensure product safety. These tests have shown that Parylene N continues to burn after a flame is removed for a short time, so products coated with Parylene N may need to rely on flame retardants in the other product materials. However, Parylenes C, D, AF-4, and VT-4 contain halogens that function as flame retardants. After removing the flame, these coatings self-extinguish at once. To test for flammability, use UL 94 V for vertical burn and UL 94 HB for horizontal burn. Although industry-specific test methods may exist, the UL 94 methods are standard and ensure reliability.

 

More Information on Parylene Services

 

The Big Picture

 

Temperature limits are an essential parameter that should factor into your decision about the type of Parylene you should use for your project. If your environment is challenging, with extremely high temperatures, the more exotic fluorinated Parylenes such as AF-4 and VT-4 are good choices. If the temperatures your Parylene-coated product is exposed to are limited, Parylene N and C are available options.

Put careful thought into which Parylene to use in the early design phase so that you can fully consider product engineering recommendations that may include product design changes. Having this conversation will improve coating performance, your product’s reliability, and your company’s reputation. There is a suitable Parylene to match any need for various conditions and environments; it’s a matter of clearly conveying these conditions early in the planning process.

Do you have questions about the Parylene coating process? HZO has Parylene coating equipment, Parylene masking automation, and Parylene removal expertise to lower costs. Contact us today to speak to one of our engineers about your project.

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Parylene Coating Thickness – How Much is Enough?

August 18, 2020 / by Dr. Sean Clancy posted in Parylene, Coating Properties

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If you are considering a Parylene coating for your printed circuit board assembly, you may wonder what thickness you should use. You may have surmised that the more coating, the better, but that is not always true. The thicker the coating, the longer it takes to coat – you will face diminishing returns at some point. Additionally, no universal thickness is ideal for all operating environments and applications. Different applications have different functional requirements.

To gain a better understanding, let’s look into how Parylene coating works and how to determine what Parylene thickness is most suitable for your requirements.

 

What is the Parylene Coating Process?

The Parylene chemical vapor deposition process begins with dimer, which is a powdered chemical. The more dimer that is in the first chamber, the thicker the coating will be. The dimer is heated into vapor, pulled by a vacuum into a connected chamber, and heated to an even higher temperature, further pyrolyzing the dimer. It is pulled into a final deposition chamber, penetrating crevices, coating exposed surfaces, and becoming a polymer. The resulting coating exhibits strong barrier properties at 50% thickness of conventional conformal coatings.

Read about Parylene biocompatibility and Parylene removal.

 

What Parylene Thickness is Best?

  • Are there Parylene cost considerations to meet, or do you need to meet the highest level of protection, no matter the price?
  • Are there time constraints?
  • Do you need to meet industry-standard requirements?

When Time is an Issue

Do you have a project that needed to be completed yesterday? A thinner coating may be your best bet. However, you risk breaches or pinholes in the coating when you go thin, say, 0.1 to 5 μm (microns). If your product has simple geometry or relatively flat structures, your coating will probably be pinhole-free.

But for products with more substantial differences in structural or component heights or components with more complex geometry, this level of thinness may not offer enough coating material to form a coherent film, leaving voids or pinholes. And any breaches in the film are potential pathways for the ingress of corrosive compounds and would require Parylene removal.

On the other hand, a thinner coating may provide a sufficient level of protection for products not exposed to corrosives, such as products requiring only a quality barrier against minimal exposure to contamination. Additionally, you decrease the time to coat and cost when you go thin.

 

Learn More About Parylene’s Chemical Resistance

 

a coating expert double checking the parylene coating on a PCB

 

For Product Reliability

Is product reliability the largest of your concerns? The IPC-CC-830 and MIL-I-46058 coating standards might be good references. According to these standards, thickness ranges of 12.5 to 18 and 12.5 to 25 μm, respectively, are thick enough for protection against very harsh environments. Coatings this thick are pinhole-free for a myriad of products and are time-tested, with decades of usage in demanding industries such as defense, aerospace, medical device, and telecommunications.

For products in the most demanding of environments, the NASA-STD 8739.1 standard calls for a range of thicknesses from 13 to 51 μm. This thickness is more than sufficient to provide a level of protection for incredibly harsh environments. Bear in mind, however, that at thicknesses around 50 μm, a single coating run may take well over a day, depending on the Parylene type you have selected.

 

Read about Parylene C and Parylene N

 

The Big Picture

There is no optimal Parylene coating thickness across all applications and requirements. Instead, you should select a thickness based upon several factors, such as the operating environment that your product will be exposed to, and how your customers expect to use the product. Additionally, budget and timeframe are essential factors. Although there is no perfect thickness of coating suitable for every application, with enough planning, you can find the perfect thickness suitable for yours. 

 

Read more about Parylene's temperature range

Although there is no perfect thickness of coating suitable for every application, with enough planning, you can find the perfect thickness suitable for yours.

Not Sure Which Parylene Thickness is Ideal for Your Product?

If you have questions or problems with Parylene, we’ve got a solution. To speak to an applications engineer about your specific requirements, Parylene coating cost, and how to determine which thickness is best, contact us today for a quote. We can help with automated Parylene masking and scalable Parylene coating equipment.

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Polyurethane Conformal Coatings - Benefits & Applications

June 23, 2020 / by Mallory McGuinness-Hickey posted in Conformal Coatings, Coating Properties

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Conformal coatings are polymeric materials applied to a PCB to improve device reliability. These films protect electronics from environmental threats, including humidity, liquids, and corrosive substances.

Different conformal coating materials include acrylic coatings, silicone, epoxy, and Parylene. Polyurethane is another common conformal coating material.

Learn how to choose the best conformal coating

 

 What is Polyurethane Conformal Coating?

Polyurethane coatings are tough, hard, protective layers resistant to solvents and abrasion.

Polyurethane conformal coatings have the following attributes:

  • Moisture and oil-resistant
  • Fungicidal
  • Good flexibility
  • Can be thinned to achieve a chosen viscosity
  • Class F temperature rating (160°C/320°F)
  • Retain excellent electrical insulation properties after the MIL-I-46058 cycling test.

 

Polyurethane Conformal Coating Benefits

Polyurethane can augment devices, extending their lifetime and ensuring they dependably operate wherever deployed.

These coatings exhibit sturdiness and strong resistance to humidity and organic solvents. The tough coatings are resistant to mechanical wear. Additionally, Polyurethane can mitigate the growth of tin whiskers.

 

Polyurethane conformal coating on a PCB

 

Polyurethane Conformal Coatings Applications

 

Polyurethane coatings are ideal in areas with technology that will face excessive chemical exposure.

Urethane coatings protect and insulate motors, generators, relays, transformers, and other components. This coating material is also common in automotive and aerospace environments. Urethane coatings protect these electronics from chemicals and salt sprays throughout temperature fluctuations.

 

What Do Polyurethane Conformal Coatings Protect Against?

The coatings protect electronics from thermal shock, moisture, chemical solvents, and other elements. Compared with other materials, Polyurethane has a lower degree of friction and high abrasion resistance.

 

The Polyurethane Conformal Coating Process

Polyurethane is available as either single or two-component formulations and can be applied with dipping, spraying, and brushing methods. After application, the films are cured to complete the coating process, which takes an hour to several days. Single-component urethanes are easy to apply but take up to days to finalize. Meanwhile, two-component formulations cure within hours. The length of the process is also related to temperature, curing faster at moderately elevated temperatures. UV curing and heat catalyzed, and moisture curing are common methods to cross-link urethane polymers.

 

View a webinar about designing conformal coatings for reliability

 

Polyurethane Disadvantages

As mentioned, Polyurethane conformal coatings have benefits, such as abrasion, thermal shock, and moisture resistance. That said, the coating also has disadvantages. The curing process can be timely and requires a long post-cure time, and moisture impacts the cure rate and cured properties. The coating can also turn yellow with age.

 

Learn How to Choose the Best Conformal Coating for Your PCB

 

The Big Picture

Choosing a conformal coating material extends beyond just looking at the material and application methods. It is important to consider various variables, including the components’ complexity, environmental regulations, and coating rework and removal. Repeatable processes that avoid defects may be important, especially for high-reliability applications.

Please read our definitive guide for more information on choosing the best conformal coating for your PCB. Alternatively, contact our Applications Engineering team for a consultation if you require more assistance. Or, you can learn more about the protection capabilities of coatings.

 
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Parylene - Different Types & Properties Explained

June 5, 2020 / by Mallory McGuinness-Hickey posted in Parylene, Coating Properties

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Parylene is a chemical compound applied to substrates using chemical vapor deposition (CVD). Because Parylene coating deposits onto the surface molecule by molecule, it forms a defect and pinhole-free coating with excellent conformality. Parylene resists chemicals and can protect against caustic substances, acids, corrosion, and more. Unlike conventional conformal coatings, Parylene is ultra-thin, providing superior coverage at 50% thickness. Several types of Parylene coatings enhance its adaptability, all suited for various industrial applications.

 

What’s the Difference Between Parylene Types?

The Parylene types covered in this guide are all characterized by different chemical compositions and physical properties. Parylenes have different levels of permeability, dielectric strength, and other defining qualities. Choosing the best one depends on what application you’re using it for and what substrate you’re coating.

Here are several different types explained, including the best application use:

 
parylene n dimer

 

1. Parylene N

Parylene N consists of a linear carbon-hydrogen molecule structure. It’s the most fundamental, basic form of Parylene, making it suitable for devices with high-frequency use. This type is distinguished by its vacuum stability and low dielectric constant. When going through the deposition process, Parylene N and Parylene C have a higher deposition rate than many other types. This quality makes it convenient for commercial use, although it’s less widespread than Parylene C.

Read more about Parylene N.

Parylene N is also halogen-free. Halogens include elements like fluorine, bromine, and chlorine. This quality generally makes Parylene N preferable to other conformal coatings, as some industries require their coatings to be halogen-free. For example, halogens in electronics can bio-accumulate within living beings and can be toxic to the environment when burned.

The most common applications for this Parylene conformal coating include the following:

  • Printed circuit boards: Most Parylene types protect the delicate inner workings of complex circuitry.
  • Elastomers: Manufacturers use Parylene N to coat elastomers, polymers with weak molecular forces.
  • Electronics: Most types of this material are excellent for protecting electronic devices, whether medical or non-medical.
 
Need to see if HZO Parylene meets your specifications? 

 

parylene c dimer

 

2. Parylene C

Moisture-resistant Parylene C is similar to Parylene N because it contains a carbon-hydrogen molecule structure. However, for each molecule, it possesses one chlorine atom in place of a hydrogen atom. As a conformal coating, Parylene C provides a protective barrier for printed circuit boards. Parylene C is an ideal coating for applications that require corrosion inhibition due to its low permeability.

Like other types, Parylene C is added to a substrate using the parylene coating process, chemical vapor deposition.

Learn more about why Parylene is used

If you have a device that needs high levels of protection, Parylene C is one of the best coatings available. Here’s where you’ll often see it being used:

  • Medical Devices: Parylene C has been used in previous medical device studies as a substrate for peripheral nerve electrodes. A nerve electrode connects neurons to a brain-machine interface (BMI) and records nerve signals.
  • Microelectromechanical systems devices (MEMs): Parylene C is often used to coat MEMs devices, though it can also serve as a structural or substrate material.
  • Caustic environments: Devices that experience constant exposure to caustic substances fare better with a Parylene C coating because of the room temperature coating process, which enables pinhole-free Parylene barriers.
Parylene F (VT-4) dimer

 

3. Parylene F (VT-4)

Parylene F doesn’t see the same commercial use as the other types on this list. However, it still possesses desirable qualities, such as a low dielectric constant and great thermal stability. It also allows for a higher coating density when used in various applications. This Parylene coating is characterized by its fluorination due to having fluorine atoms in its aromatic ring.

Although it’s not as widespread, its properties can serve well for things such as:

  • Field-effect transistors: One study showed that Parylene C and F were used within field-effect transistors to produce copolymer gate dielectrics. The study’s results showed that Parylene copolymer dielectrics offered stable and high-quality performance without requiring extra manufacturing steps.
  • Microelectromechanical systems devices (MEMs): Like Parylene C, the F type also lends itself well to MEMS — especially those with high-temperature requirements.
  • Harsh conditions: Parylene F resists high temperatures and ultraviolet (UV) radiation. Because of these properties, it could serve as a suitable substitute for Parylene C under harsh conditions.

 Learn more about Parylene temperature range

Parylene D dimer

 

4. Parylene D

Parylene D resembles Parylene C in that it substitutes two hydrogen atoms for two chlorine. Both of these materials come from the same root monomer. Parylene D, however, lacks the same ease of use that C does — especially in terms of biocompatibility. It can hold up well when exposed to high temperatures, but it doesn’t work as effectively for coating things like medical devices.

Learn about Parylene optical applications.


Parylene F (AF-4) dimer

 

5. Parylene F (AF-4)

Parylene F (AF-4) possesses high oxidative resistance and UV stability. These properties make it suitable for specialized applications. It can withstand UV exposure without experiencing surface yellowing or degrading, which adds to its durability.

However, creating this conformal coating requires a three-step process. The additional stages increase production costs while limiting the yield, so saving this Parylene for only highly specialized uses is best. These include high-temperature applications and UV radiation protection.

 

Contact HZO for Parylene Conformal Coatings

If you’re interested in coating your devices, HZO can assist you. We serve a range of industries to help device manufacturers meet specifications, no matter the products produced.

Our turnkey solution helps us meet your coating needs by providing industry-leading, state-of-the-art Parylene coating equipment and employing proven material science. We have expertise in Parylene removal and industry-leading Parylene masking automation that reduces the price of Parylene coating services. Combining the entire package, HZO can offer you a high-quality experience with a durable finished product. Contact us today to speak with one of our highly qualified engineers about Parylene coating solutions.

 
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Epoxy Conformal Coating Evaluation Guide

May 21, 2020 / by Ryan Moore posted in Conformal Coatings, Coating Properties

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Conformal coatings are polymeric materials applied to substrates. These films are a barrier to protect electronics from environmental hazards, such as corrosion, humidity, chemicals, and liquids. Popular conformal coating materials include silicone, acrylic, Parylene, and urethane. Epoxy is another coating material of choice in applications where chemical and abrasion resistance are priorities.

 

What is Epoxy Conformal Coating?

Epoxy coatings are protective layers with excellent electrical, thermal, mechanical, and moisture barrier properties. 

Epoxy coatings have the following attributes:

  • Very robust, difficult to remove the protective coating
  • Excellent chemical and abrasion resistance
  • Very rigid conformal coating
  • High dielectric strength

Epoxy Conformal Coating Applications

Epoxies are highly abrasion-resistant and tough and, therefore, common in applications with harsh environments, including automotive, marine, and military. Different types of epoxies have different benefits as well. For example, thermally conductive epoxy can protect boards with components that give off heat. Meanwhile, flame retardant epoxy is useful for fire hazard protection, and clear epoxy allows for board visualization.

 

epoxy conformal coating
 

 

What Does Epoxy Conformal Coating Protect Against?

Epoxy conformal coatings resist chemicals, alkalis and acids, moisture, organic solvent, and salt spray. They are known for excellent adhesion to various substrates without needing primers and retain adhesion under many conditions. Additionally, they have good electrical characteristics, and these parameters remain stable despite humidity or elevated temperature.

 

The Epoxy Conformal Coating Process

Applying epoxies with dip coating, brush, or spray application techniques is easy. With dip coating, a component is immersed in a tank of coating material, while brushing entails manual application by an operator. The spraying method can be automated or manual, depending on production needs. Epoxy materials come as either a single or two-part compound and require curing with UV or heat exposure.

Learn About Conformal Coating vs. Potting

 

Why Choose Epoxy Conformal Coating to Protect Your Electronic Devices?

Epoxies are a common coating material choice due to their strong barrier properties, ease of processing, and low cost. That said, the toughness and durability of epoxy coating may pose challenges with rework and removal. Film shrinkage may occur during polymerization, potentially causing issues, and the suggested thickness for epoxy coatings can reach up to 130 micrometers. This thickness may prove too bulky for applications that entail miniaturization.

Understanding material properties and how they meet your requirements is a good start if you are trying to determine which coating material is best for your PCB. However, other factors must be considered, including masking, cleaning, inspection, scalability, coating removal, and avoiding and addressing defects. For a big-picture view, read our guide to choosing the best coating or learn more about coatings’ protection capabilities. Alternatively, please contact us to speak to a coating service expert about your application one-on-one. 

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How Small is a Nanometer? Nanometers Explained

November 14, 2014 / by Ryan Moore posted in Coating Properties, PECVD Coatings

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We live in a growing world. Every day, cars are getting bigger, buildings are getting taller, phones are getting larger, and Americans are getting wider (I can say that; I’m an American). But here at HZO, we are getting smaller. In fact, we are obsessed with getting smaller. Every day our engineers, chemists, and recently added physicist work tirelessly to make HZO’s already minuscule technology smaller and even less invasive.

The prefix “nano” is used in many different industries and in many different contexts, but no matter the situation, it is used to describe something that is really, really, incomprehensibly tiny. In fact, it’s used to describe and measure things on the molecular level.

But how small is small? Let’s put it into perspective.

  • The Empire State Building is more than 443,000,000,000 nanometers tall.
  • Shaquille O’Neal is 2,160,000,000 nanometers tall.
  • A single hair on your head is 100,000 nanometers wide.
  • A common germ is about 1,000 nanometers wide – I don’t know about you, but the fact that we can measure a germ makes me want to wash my hands more often.

 

So what’s the big deal? Why does this matter? At just 5,000 nanometers, our coating is 20X thinner than a single strand of hair (and if you’re counting, that’s 43,200X thinner than Shaq). Unlike other materials, HZO’s nanotechnology bonds to practically any surface and creates a tight, conformal layer that keeps corrosives and contaminants at bay. Our nanocoating process offers a robust protection solution against liquid submersion for electronic components and devices. Since our micro-thin material is applied directly to the electrical components, there is no change in the weight, look or feel of the device after the treatment has been applied.

So, long story short, and a few useless facts later, HZO protects your devices in ways that no other technology can by applying a thin film that is durable and consistent, protecting electronics from corrosion and failure that occurs as a result of exposure to any kind of liquid. It protects at the microscopic level, and it doesn’t just keep water and other liquids away from the all-important electronic components, but it literally changes how these liquids and corrosives react to the protected surface. Contact us today if you have a device or product you want to protect.

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