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Plating silver on stainless steel

 

We have a part that is made of 316ss and it is to be plated with silver so that it can be soldered to a micro circuit. We have problems of the silver flaking off in large chunks, exposing the stainless base lead, thus rendering it useless to solder. Is there something inherent to the process that is special in plating the stainless material? The material is 0.0001" thick X 0.0005" strip X 2.0" long.

Peter Zendzian
- St. Croix, Virgin Islands

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Absolutely you need a special preplate process for stainless steel.

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

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It sounds like you have poor adhesion. I would suggest you look critically at your cleaning process for the stainless steel and then consider giving it a good etch. It is essential that you do not let the stainless re-passivate, or you will lose adhesion again. It is also worthwhile using a silver strike to improve the adhesion of the silver to the stainless. This will contain cyanide, so be very careful! Neutralise the cyanide and then give the article a heat treatment prior to any thickening of the metal deposit. This will remove any co-deposited gas that, when heated, will lead to failure.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
 

After years of experience plating on stainless (300, 400 and a bunch of alloys), I've come to realize that there is one step that is absolutely critical for satisfactory adhesion- a Wood's nickel strike. Formulation is available in any plater's handbook.

George Brackett III
- Utica, New York