Conformal coatings are also “breathable”, allowing trapped moisture in electronic boards to escape while maintaining protection from environmental contaminates. However these coatings are not sealants, and prolonged exposure to vapors will cause transmission and degradation to occur. There are typically four classes of conformal coatings: Acrylic, Urethane, Silicone, and Varnish. While each has its own specific physical and chemical properties each are able to perform the following functions:
- Insulation: Allowing reduction in conductor spacing
- Eliminate the need for complex, sophisticated enclosures
- Minimal effect on component weight
- Completely protect the assembly against chemical and corrosive attack
- Eliminate potential performance degradation due to environmental hazards
- Minimize environmental stress on a PCB assembly
Conformal coating, typically applied at 25-250 μm(micrometers) thickness, it is applied to electronic circuitry to act as protection against moisture, dust, chemicals, and temperature extremes that, if uncoated (non-protected), could result in damage or failure of the electronics to function. When electronics must withstand harsh environments or impact, protection is provided with conformal coatings or potting compounds. Most circuit board assembly houses coat assemblies with a layer of transparent conformal coating, which is lighter and easier to inspect than potting.
Because of the vast range of electronics in today's world, a printed circuit board is expected to perform in a huge range of environments. Circuit boards then are exposed to a vast array of different conditions such as moisture, salt, chemicals and temperature changes to name but a few, conformal coatings are designed to protect the electronic components from these varying conditions and prevent the board from corroding.More recently, conformal coatings are being used as a mitigation to reduce the potential of risks.
Tag : Conformal Coating