Metal finishing Q&As since 1989

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Question re: Acceptability of Plating Nodules

I am a Materials Engineer, and in reviewing industry plating specifications, Nickel and Silver in particular, I read that no nodules are acceptable. Can anyone tell me what some of the detrimental effects or impact nodules can have on a nickel or silver plated part? Is it simply a question of whether or not they may fall off, or is there more to it?

Thank you for your help.

Diane Burchett
Engineer - Cambridge, Ontario, Canada
2004

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2004

Unfortunately, I don't think there is really any way to answer your question, Diane. Nodules represent one possible plating defect. Maybe they could fall off and short out a life support machine, maybe they could tear up the seals as a plated cylinder rod moved in and out, maybe they could serve as an antenna to radiate electronic noise.

A customer has a right to expect that his/her plated part will be free of nodules, and this particular point in the specification is intended to remove any doubt about that expectation. If I haven't answered appropriately, please re-word your question.

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

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It is virtually impossible to not have edge nodules if you are plating 0.025 inches of sulfamate nickel, but you certainly should not have nodules on 0.001" of nickel. Nodules in the main plated surface normally means trash in the plate or that the prep process has opened up some of the surface that was smeared by a poor machining process.

So, it depends on what the application is.

James Watts
- Navarre, Florida
2004