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Nickel plating is coming out black
Current question:December 31, 2020
Q. Respected All,
I am Shankar Rathod, India, working in medical-based company. I am doing Nickel Bright plating for some of our applications.
I have maintained all concentrations properly and maintain pH 4.8 also. But when I was started dummy jobs that time some black layer is deposited on MS and SS parts.
I had tried two or three times, same issue I have found.
I am not chemistry person. I have read some papers and videos and I made this setup.
I am waiting for your kind response.
- Bangalore, India
Previous closely related Q&A's starting in:April 10, 2012
I work as a chemical engineer in decorative chrome and zinc plating plant. I have a problem with my semi-bright nickel. The metal pieces after semi-bright nickel appears black. I checked the current, if anodes are inert, I made treatment with filter pump and active carbon and it didn't help. I took off the plating solution and treated with sodium carbonate (washing soda) [affil. link to info/product on Amazon], hydrogen peroxide, active carbon again and tomorrow I will return and see the results. I suppose that solution is contaminated with copper(II) carbonate. When we took off the solution there was brown layers all over the tank and on the heaters and on the bottom there were very beautiful green crystals for which I think that may be nickel carbonate.
Had somebody similar experiences or can somebody guess the reasons? My colleague have for 30 years worked in plating and have never seen this kind of trouble.
Solar Tubes - Prilep, Macedonia
April 25, 2012
A. Dummying (low current density electrolysis or LCD Plating) at reduced pH (2.7-3 pH) is the only way out. Plate for two hours continuously using large area made of corrugated (zig-zag bend) cathodes and minimum anode. See the result ... clean the cathode. Do it until you get a clear finish on the sheet, then increase the pH to the working range.
Best of luck.
plating process supplier - Mumbai, India