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Ted Mooney, P.E. RET
Pine Beach, NJ
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for Metal Finishing since 1989
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Nickel Sulfamate Plating is Peeling from Copper
Q. We are nickel plating (using a nickel sulfamate bath) copper plates. The tanks use nickel sulfamate, boric acid, nickel chloride, and an anti-pitting additive. The etching for the copper plates is done using a sulfamic acid solution.
Recently, we have been experiencing an increased number of peeling incidents. It is happening on the end of the plate that sits lowest in the tank. They are small peels that show up after we flame test the plating (our plates are used in steel manufacturing, so they must withstand high heat).
The tanks are tested regularly, with no evidence of chemical imbalance in the solution. We originally assumed it was a preparation issue, but the platers follow all guidelines properly and consistently regarding etching.
I am starting to run out of ideas. Our only assumption left is that organics in the tanks are getting too high. Is this something that can cause peeling? Any other suggestions?
- Oil City, Pennsylvania
November 4, 2021
November 10, 2021
A. 1. The bottom of your flume is the high current density area, so if the tensile stress has climbed then the stress is pulling it up. Use your spiral contractometer and see if the stress is too high.
2. I remember some of your copper is loaded with zirconium and chromium which contributes to adhesion problem. Try to copper plate it first, check that for adhesion, then start the SN nickel.
Robert H Probert
Robert H Probert Technical Services
Garner, North Carolina
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