Metal finishing Q&As since 1989

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Can Sulfamate nickel on aluminum act like an insulator?

2007

Hello-
Sorry, I'm new to Finishing dot com, so I will phrase my questions the best that I can. We recently had a vendor plate an Aluminum piece with dimensions of 2"x2"x0.1" using Nickel Sulfamate. We expected the piece to be conductive because sulfamate nickel should have a resistivity of approximately 2.1336E-05 ohms-in. However, when we received the plated piece they act like insulators when we take ohms measurement. Could the vendor plated incorrectly? Any suggestions would be great.

Thanks,

Mike Schoch
product designer - Everett, WA

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Mike,
Are you saying that there is no electrical contact between the nickel and the aluminium? As a rule of thumb, all metals conduct electricity, so in theory the aluminium-nickel system should be conductive. The preparation of aluminium for electroplating involves the "zincate process" which in itself does not create a very good conducting layer, but once the full process has been completed, the final sandwich should be OK. I would suggest you check to make sure the nickel coating is electrically conducting - if it isn't there is something horribly wrong with the nickel, or your meter doesn't work properly!

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2007

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Seems the aluminum has a weathered oxide. Just punch the meter leads in a little harder and it WILL pass current.

Robert H Probert
Robert H Probert Technical Services

Garner, North Carolina

2007

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Thank you for all your help, I will try your suggestions.

Thanks,

Mike Schoch
- Everett, Washington
2007