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  for Metal Finishing since 1989
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416SS and Brass, suggestions for a better Galvanic compatible pair?

A customer has a small sensor which attaches to the skin of human subjects. The sensor has two button sized 416SS contacts which screw into threaded brass inserts. Sweat on the subjects skin is causing corrosion between the brass and stainless steel. Wires inside the sensor solder onto the brass inserts. Are there better choices of material and/or plating which will solve the problem?

Thank You,

Phil Austin
- Lenoir City, Tennessee, USA
2007

If these are only a few, the cheapest way would be to use a local jeweler that does a very thin rhodium plate. Make sure that he/she understands that it is stainless and that they can plate it. If it is a large number, I would have them gold plated. Zinc corrodes, electroless nickel would not work as about 1 in 20 people are nickel sensitive, chrome would not work as well and would be just as expensive, silver corrodes. White brass is an option, but not many shops do it.

James Watts
- Navarre, Florida
2007

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2007

Neither brass nor 400 series stainless steels alone are suitable for prolonged contact with human skin and sweat. Less so if put together, for they will automatically form an active corrosion potential (galvanic pair). Besides the corrosion issue they may cause rash, stains, etc. For prolonged contact, one of the many metals or coatings frequently found on watches and jewelry must be used
(gold, gold plating, rhodium, rhodium plating, platinum, platinum plating, titanium, etc.).

Guillermo Marrufo
Monterrey, NL, Mexico