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Spots, pinpoints and blackish color in nickel plating

I am doing plating on ss. first I do bright nickel sulphate watts plating for 15 minutes, then I do copper plating with brigh cupracid bath for 1.5 hours, then again nickel plating for 15 minutes, each followed by cleaning with DM water.

I am getting spots or pinpoints on the top layer, and sometimes the top layer of nickel get blackish finish.

I am new to plating. I did carbon treatment to nullify any impurities but it has not helped much.

both baths are maintained .

help required immediately!

Satyam Gogia
plating shop - Delhi, India
April 14, 2008

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Satyam,
A low efficiency Woods Nickel Strike should be used when plating directly on s/s, especially when a Ni sulphate layer is to follow. The higher thickness is then built up with your nickel sulphate. You have to be sure this nickel layer is active before going into the copper or peeling will occur. Good Luck.

Mark Baker
Process Engineer - Syracuse, New York
April 20, 2008

A wild guess-- You have too much brightener in the copper and it is not 100% active when it goes into the nickel tank. Why are you doing nickel-copper-nickel vs copper -nickel. Possibly two different nickels if corrosion is a problem.

James Watts
- Navarre, Florida
April 21, 2008