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Decorative Nickel Tank Problem: Passivation

2000

Hi, I'm in the decorative chrome business and I have encountered a problem with my nickel tank whereby I am getting nickel passivation. When I place a piece into the chrome tank, I get a "root beer" effect, e.g. brown spots on the parts. So far, I have tried

• -carbon treatment
• -complete cleaning and testing of equipment
• -complied with all of the recommendations suggested to me by my nickel solution supplier

I should point out that the nickel solution in use is fairly new on the market which leads me to believe that perhaps there is a flaw with the solution itself. However, any help or suggestions to my problem will be much appreciated. Thanks.

Jack Prevost
- Quebec, Canada

Hi Jack.

How long time is it between nickel plating and the chrome plating when you move the part from nickel to chrome solution. Also you can have too much brightener in nickel solution. Maybe you turn on the current too fast? -- let the part obtain the chrome solution temperature before you raise the current.

Regard

Anders Sundman
4th Generation Surface Engineering
Consultant - Arvika,
Sweden
2000

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Dear Jack:

We have experienced this in the past from time to time. We have found that if the pH is too high (>5.0) in the bath or the dead rinse the problem sometimes arises. I say sometimes, because this is not always the case. Most of the time if we lower the dead rinse too between a pH of 3.0 to 5.0 with sulfuric acid the problem usually goes away. This may not be the cure, but it gives you something to try. KH

Ken Hutchinson
- Minneapolis, Minnesota
2000