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Semi-Bright Nickel/Chrome Electroplating Problem
2005
semi-bright Nickel / Chrome on brushed brass substrate.
Typically we have less than 1% reject rate.
We performed a routine, yearly pump out on our semi-bright nickel bath.....as we do every year without a problem.
Upon start up we had a problem with poor chrome coverage. In the area of poor chrome coverage, the LCD area.......the nickel was very thin. The reject rate was 20-30%...very unusual for us. We were able to rechrome most of the parts....but really affecting our first pass yield. We were able to successfully plate once we decreased our production and increased the amperage.
ALL Chemistries appeared fine and were verified by our supplier. We thought there was an electrical issue because the one thing that was found at the pump out, was one of the two coils in this large, dual station tank, had been plating. We checked this out and installed new di-electric unions. Now...we wonder if it is an unusual organic problem, as the Hull Cells indicate no problem. When doing a
2 amp / 10 minute panel in the lab.....with an 'as is' and a carbon peroxide treat....we did find that the thickness of nickel was more on the panel that had been carbon treated. We started changing the filter more frequently with extra carbon (we do continuous carbon filtration). This seems to be helping. We are still running higher than normal amperages, but we have been back to our normal load size
(normal production).
I would like some other opinions or thoughts, if anyone has some. It is so frustrating when something bites you and you are not 100% sure what it is, and, sometimes, it disappears on it's own and you never learn from it!
Thanks......
Captive Plating Shop - Indianapolis, Indiana, USA
Hello Gloria,
A sluggish plating rate seems to be a contamination problem.
A mentor in this field once cleared out a similar problem in my bright Nickel, that is we added 0.1 gms per litre of Silver Sulphate in the Nickel bath.
No harm in trying it out.
Khozem Vahaanwala
Saify Ind
Bengaluru, Karnataka, India
2005
2005
Contamination, try to "clean" the electrolyte by using folded steel sheets and very low current.
Make sure that the sulphate content in the chrome solution is below
0,75 grams/liter. It affects the throwing power really much.
- Sweden
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