Scaling Buildup in Nickel Sulfamate Plating Process
April 10, 2012Q. I have a Nickel plating process which uses the SNR-24 from MacDermid. I'm currently having a unique problem in that every 2 months I find that the levels of Boric Acid drop and a precipitate is forming in the tanks and builds up on the surfaces of the walls of the tanks.
Does anyone understand where the Boric is going and what is causing this precipitate to form?
- Salt Lake City, Utah, USA
A. Hi Bill.
Does the power go out and the tank temperature drop every two months? Boric acid is only sufficiently soluble at operating temperature.
Regards,
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 Ted Mooney, P.E. RET finishing.com Brick, New Jersey |
A. Boric acid is not consumed during electrodepositing nickel. However, boric acid is unusual in that when it comes out of solution, it is very difficult to redissolve. I think Ted's comments are good, but I would suggest analysing the precipitate for boric acid, just to make sure it is boric acid. If the solution does cool down and the boric acid precipitate out, it may well be filtered out in your filtration system, so check that too. I would suggest that you ensure the bath is kept warm, so that the solubility limit of boric acid is not exceeded.
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Trevor Crichton R&D practical scientist The Pheasantries - Chesham, U.K. |
April 27, 2012
Q. The temperature is well controlled and we do not see any temperature fluctuation. I've had the precipitate analyzed and they find Boron, Nickel, Sulfur components but nothing that I wouldn't normally see in our tank. Our water system is filtered by RO Membrane and I've just had it checked to confirm that it's working properly. All the inputs are clean, I'm not understanding what could be happening with the chemistry to cause a precipitate formation and decrease of boric acid. We are operating our tank at 128° F +/- 2° F.
The precipitate itself will only dissolve in acidic solution.
- Salt Lake City, Utah, USA
A. Hi Bill.
I don't have tech data sheet for SNR-24, but I thought that most nickel plating solutions containing boric acid operated at 140° F.
Regards,
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Ted Mooney, P.E. RET finishing.com Brick, New Jersey |
A. Get out your high school chemistry book and look up what percentage of boric acid is "boron".
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Robert H Probert Robert H Probert Technical Services  Garner, North Carolina
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