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  for Metal Finishing since 1989
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Corrosion problem Nickel plated Phosphor Bronze

Q. We currently have a corrosion problem on our so-called limit switch contacts. They are a SAE CA510 .010" thick Phosphor Bronze material that we have nickel plated. Our nickel plate call out is BRIGHT (not sure in the industry what this stands for as far as thickness, etc.) nickel and uses the ASTM B322-85 as far as cleaning the parts beforehand. The contacts sit in a plastic housing and there only contact is with another contact with the same properties. Our question is should we specify a different Nickel finish or possibly there is some other material that could serve our purposes that wouldn't need to be plated and that would run around the same cost (if not cheaper) but have the same material properties as the Phos. Bronze? Possibly, we just need to specify a thicker nickel plate or something of that nature.

Thanks.

Steffen J. Weech
Chamberlain Group, Inc. - Nogales, Arizona USA
2000

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Phosphor bronze components made from strip becomes blackish after nickel & tin plating

Q. We make components from phosphor bronze strips. They are first plated with nickel ( 4- 5 microns) and then tin plated (12 - 15 microns). Recently we are observing very odd phenomenon. 2-3 hours after plating, edges of components appear blackish. Black colour starts increasing as time passes. We are not able to investigate reason for this. If we plate copper in same tin bath, no problem is observed. Kindly guide us in this matter.

Zankar Desai
- Vadodara, Gujarat, India
2006