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Reduced Efficiency of Nickel Deposition

I am using 0.1N nickel sulphate solution (pH 5.2)for electrodeposition from Ni anode to Ni cathode . I have 50% cathode efficiency. Is it reasonable? I have read that for soluble nickel anodes, efficiency of anode and cathode is very high. What could be the reason?

Cintu
Student - Cleveland, Ohio
2004

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I think your pH is too high by about 1.0 and suggest reducing it with sulfuric acid. The efficiency is very high at low current density, but significantly lower at high current density. What is the current density?

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

I am working with current density of 2 mA/cm2. and I see bubbles evolving at the cathode..is that hydrogen and does it cause the reduction in efficiency?

Cintu
- Cleveland, Ohio
2004

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2004

Your current density is less than 2 Amps per square foot in English units, which is quite low, but perhaps not low for the very dilute plating solution you are using. The bubbles are indeed the evolution of hydrogen, which is where the electricity is going which is not depositing nickel.

I didn't really pay attention to your nickel concentration the first time I looked at your letter. If I did the calculation right, it is about 1/30th of usual plating strength, which I would expect to lead to low efficiency. Is there a reason you are using this solution instead of a more concentrated one?

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

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