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Product design

I am designing a very small electrical mechanism. I have a 301 stainless steel lever with no plating pivoting in a notch in 260 brass piece with 200 microinches of silver. The ss lever wears into the brass before I meet my life requirements. I can not change my base materials or silver plating. Is there any plating I could put under the silver plating (on the brass)to improve the hardness to prevent wear? It is ok if I wear through the silver. Is there any plating I can add to the ss lever to act as a dry lubricant to reduce the wear of the brass? I can not contaminate the mechanism with any organic material.

Frank Domzalski
product designer - Natic, Massachusetts, USA
February 5, 2009

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You need 0.0003 inch of nickel electroplate between the brass and silver for two reasons. (1) Hardness, and (2) diffusion barrier to prevent silver migrating into the brass.

Also, if the brass is leaded, the surface prep is a bit unusual for most job shops in that lead is insoluble in sulfuric acid and Hydrochloric acid. To plate on leaded brass you need to dip thru fluoboric acid to keep the lead smears active to accept nickel plate adhesion.

Cadmium (ecologically a no no) would be a good "lubricant" to have plated on top of the stainless steel, but, again, that is not a typical job shop capability.

Robert H Probert
Robert H Probert Technical Services

Garner, North Carolina

February 9, 2009