A practical precaution against introducing zinc whiskers
Is "yellow zinc" plating any less prone to whiskers than bright?
Is a coat of metal lacquer or clear enamel effective against whiskers?
manufacturer of industrial electronics - Idaho Falls, Idaho
Dear Mr. Hardy,
Some of the earlier letters published on finishing.com suggest that Zinc-cobalt plating seems to be the plating to opt for in order to avoid zinc whiskers.
I do hope that someone could provide conclusive proof or link to any other articles on this subj.
Bangalore, Karnataka, India
Anything that alters the surface of zinc electrodeposits will reduce or eliminate the chance of forming whiskers. Yellow chromate is better than clear because it modifies the surface more. Coating with organics also modifies the surface, so helps prevent whiskering. However, having said that, some times whiskers grow regardless of the surface treatment. Stress in the deposit, and/or stress induced by bending the metal plus humidity and higher temperature and electrical or magnetic currents may cause whiskers even after all the precautions, although rarely.
Consultant - Poulsbo, Washington
(Don is co-author of the book "Plating on Plastics")