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Brass went brittle from nickel plating?

2003

Can the Nickel plating process do damage to the brass parent metal (like H2 embrittlement)? We have a small part which gets assembled by bending the leg on the part 90 degrees. Our last batch of parts are brittle, a good portion of them are breaking off. Base material is 0.009" thick, 3/4 hard brass sheet. Part measures .8" x .3".

The other possible cause might be that we used full hard brass rather than 3/4 hard. Seems like full hard should be able to bend 90 degrees without breaking.

Thanks.

William J. Cox
electric meters - Lac du Flambeau, Wisconsin

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It is possible that the nickel could cause the very thin brass substrate to break. The reason for this is that if the nickel is too hard and brittle, when it is bent, it will break. The energy released in the cracking process will be focused at the point of failure on the brass substrate and the brass could fail. This crack propagation mechanism is well known and is commonly seen in electroplated plastics (although the problem has been well resolved now!). Although I am not too sure, I would expect the thickness of the nickel in relation to the brass thickness to be influential on the likelihood of failure -the thicker the nickel, the more likely a failure in the brass.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2003