Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ

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Nickel hydroxide is depositing with my nickel plating

Q. I am trying to do basic electroplating rate studies using 2 nickel plates. Initially I used 0.1N nickel sulphate solution allowing7 mA/cm2 current through the system. I see green deposit on the cathode and I think its nickel hydroxide. Is there a way to prevent this and allow metal deposition only?

Chandrashekhar Pendyala
student - Cleveland, Ohio
2004

A. This is not a normal situation, and I'm not sure exactly what's wrong, but I suspect the pH may be rising. You should measure it, and lower it to 4.0 if it is over 4.5. Use sulfuric acid, and consider the addition of boric acid as a buffer to hold it stable.

Another possibility is that your lab partner reversed the polarity :-)

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2004

A. If you only used a solution of nickel sulphate I am not surprised you didn't get any metallic deposit. It sounds as if your pH is too high, but without knowing the bath composition, no-one can tell. Please give more detail of your bath composition, pH, temperature etc.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2004

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