HolyStone International has introduced a new coating process designed to prevent surface arcing or flashover on X7R multilayer ceramic capacitors. The material coats the surface of the dielectric without encroaching on the termination material, creating a nonporous surface that prevents moisture and dirt from being trapped, which reduces the surface resistance and arcing voltage of the capacitor.
Clive Youngs, technical and applications manager of HolyStone Europe, said: "Surface arcing or flashover is increasingly a problem as high-voltage X7R multilayer ceramic capacitors become more popular in applications such as power supplies, telecommunications, industrial equipment and modems. It can cause equipment failure during isolation testing and also may leave a carbon track on the surface that can make the capacitor fail.
"The new arc prevention coating is the first ever cost-effective solution to this problem, and we are confident it will prove a revolutionary development. Extensive testing has shown that arcing voltage of unsoldered capacitors is increased by approximately 30%. More importantly, the arc prevention coating aids cleaning of the capacitor's surface post-soldering, making any flux or dirt residues easy to remove using standard cleaning processes."
Tests have also shown that the arcing voltage on soldered capacitors can be increased by up to 65% using the company's arc prevention coating. Typical results for an 1808 X7R soldered capacitor after cleaning show that arcing voltage increases from 2200VDC for an uncoated part to 3600VDC for a coated capacitor, the company reports.
The company’s website is at
MATERIALS: New Capacitor Coating Prevents Surface Arcing - Posted 12/19/07
December 19, 2007