Epoxy Conformal Coating Evaluation Guide

Mallory McGuinness-Hickey May 21, 2020

Conformal coatings are polymeric materials applied to substrates. These films protect electronics from environmental hazards, like corrosion, humidity, chemicals, and liquids. Popular conformal coating materials include silicone, acrylic, Parylene, and urethane. Epoxy is a top coating for applications that need high chemical and abrasion resistance.

What is Epoxy Conformal Coating?

Epoxy coatings are protective layers of polymeric material. They have 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 tough and highly abrasion-resistant. So, they are common in harsh environments, like automotive, marine, and military applications.

While exact figures for epoxy coatings specifically are not provided, the overall conformal coatings market is projected to see strong growth:

The global conformal coatings market is expected to reach $1.8 billion by 2028, growing at a CAGR of 5.3%. Some estimates project the market to reach $2.11 billion by 2034, with a CAGR of 6.7%.

Epoxy conformal coatings find use in various industries and applications:
• Consumer electronics
• Automotive electronics
• Aerospace and defense
• Industrial equipment
• Medical devices

They are particularly suitable for applications requiring rigid, durable coatings with good chemical and abrasion resistance.

Different types of epoxies have other benefits. For example, thermally conductive epoxy can protect boards with hot components. Meanwhile, flame-retardant epoxy protects against fire hazards. Clear epoxy allows for board visualization.

HZO provides Parylene conformal coatings applied with vacuum deposition, so our process is different. Watch this video to learn more.

What Does Epoxy Conformal Coating Protect Against?

Epoxy conformal coatings resist chemicals, alkalis, acids, moisture, solvents, and salt spray. They are known for excellent adhesion to various substrates without primers. They also retain this adhesion under many conditions. Additionally, they have good electrical properties. These remain stable despite humidity or high temperatures.

The Epoxy Conformal Coating Process

Applying epoxies with dip coating, brush, or spray application techniques is easy. Dip coating involves immersing a component in a tank of coating material. Brushing entails a manual application by an operator. The spraying method can be automated or manual, depending on production needs. Epoxy materials are a single or two-part compound. They require curing with UV or heat.

Learn About Conformal Coating vs. Potting

Epoxy Conformal Coating Pros and Cons

Advantages

Good abrasion resistance.
Good chemical resistance.
High tensile strength.
High Youngs Modulus.
Low coefficient of linear expansion.

Disadvantages

Higher water absorption than Parylene.
Rigid, can crack in vibration or thermal cycling.
Can shrink, causing stress on components/diodes.
Very difficult to rework.
Low impact resistance.
Low abrasion resistance compared to Parylene.

Why Choose Epoxy Conformal Coating to Protect Your Electronic Devices?

Epoxies have strong barrier properties; they are easy to process and cheap. That said, epoxy coating's toughness may complicate rework and removal. Film shrinkage may occur during polymerization, causing issues. The suggested thickness for epoxy coatings can reach 130 micrometers. This thickness may prove too bulky for applications that entail miniaturization.

Need help choosing a coating material for your next project? Contact us to discuss your application with a coating expert.