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Cadmium alternative for electrical contacts

I am looking for an alternative to Cad plating for electrical contacts (low voltage 12-64V) but quite high current. Any suggestions? My understanding was that the Cad was used to prevent sticking (fusing) of the contacts.

Trevor Buss
Rebuilder - Tottenham, ON, Canada
December 16, 2009

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December 15, 2009

Hi, Trevor. There are many materials that offer low contact resistance, and electroless nickel plating is probably the most common. You see it on the charging contacts of almost everything that has a battery or an AC adaptor.

But some electromechanical relays with cadmium plated contacts were designed for a life of tens of millions of cycles in an arcing-prone situation. It's very hard to project that a finish will be good for tens of millions of cycles in arcing service just because it's been good for several hundred or a thousand in easier service :-)

This is not an answer, only a suggestion for a research or testing project, but I'd bet that tin-zinc would more closely resemble cadmium than most other candidate materials. Good luck.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey