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Peeling of silver plating

June 8, 2008

I am a manufacturer of small electrical connectors. Recently we received an order for a three-piece assembly female connector. The three pieces material are A: Sleeve(Brass Tube), Part B: Phosphorus Bronze(Middle terminal) and Part C: Sprng (Beryliam Copper). I have no knowledge about silver plating.

My vendor plated samples for me which I got approved from my customer. When I delivered my first shipment of 100,000 pieces, my customer rejected all saying that there is a 50% reject due to problem with part A silver plating is peeling. This part C sleeve is crimped to wire and after crimping the silver plating is peeling. My vendor told me that he is first nickel plating and then silver plating.

Please Please somebody tell me Do we have to Nickel plate in order to silver plate on these 3 materials? Is there a way I can buy chemicals and do plating myself.

Baljit Singh
Manufacturer - South Elgin, Illinois

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(A), you say brass. Is it leaded brass?, If so special prep is required, get back to us. (B) should require no special treatment. (C) the Be-copper will show better adhesion if first plated in an acid solution, either nickel or at least a quick strike in acid copper. Berylium is almost insoluble in a cyanide solution, so you need to cover it with an acid plate first. Many old time platers do not know this.

I assume that ahead of the silver you DO have a low metal high cyanide silver strike !

All that said, there is one more problem. Silver plated right over copper will migrate into each other and corrode, this will not affect adhesion. To keep the copper and silver separate, plate nickel or palladium in between.

Robert H Probert
Robert H Probert Technical Services

Garner, North Carolina

June 17, 2008