Why is humidity the most destructive to PCB circuits?
Moisture is the most common and destructive factor of PCB circuit board. Excessive moisture will greatly reduce insulation resistance between conductors, accelerate high speed decomposition, reduce Q value, and corrode conductors. We often see that the metal part of the PCB circuit board has a patina, that is, there is no coating of the three proofing paint, copper metal and water vapor, oxygen, together with its chemical reaction.
When three protective coatings are coated on printed circuit boards and assemblies, the deterioration of electronic operation performance can be reduced or eliminated if the operating environment is likely to be adversely affected. If the coating can maintain its function for a satisfactory time, such as greater than the use of the product, it can be regarded as the purpose of coating.