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Yellow patches on Bright Nickel plated ABS nozzle

Dear sir ,
We are doing Bright Nickel plating on small ABS pen nozzles. We find dark yellow and bluish patches on the nozzle ,irrespective of current density area, about 10 minutes after plating. Although we are using Chromic acid solution to wash nozzles before drying,but it is not satisfactory. Is it due to some problem in Nickel plating bath or else? please suggest some solution.

Manoj Satish Lohar
Electroplating - Mumbai, Maharashtra, India
2005

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To eliminate a problem in the bath do a Hull Cell test. If you get the colouration on the Hull cell, it is the bath. If not, it is something else. Why do you dry after chromic acid etch? This will reduce the effectiveness of the etching. Are you sure the chromic acid is fully neutralised? Personal experience has shown it can be very difficult to achieve, even with high concentrations of sodium metabisulphite. Try using plasma etching to activate the ABS - it is cleaner, faster and less polluting. I suspect you have a chromic acid problem, but do the Hull Cell first.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2005

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2005

Dear Manoj,

You are doing nickel only or nickel chrome?
1) If nickel chrome it because of low sulphate in chrome.
2) After chrome cleaning if rinsing is not proper ,the chrome water inside nozzle may be coming out.

So please check these points.

Vishwas Nangare
motorcycle accessories mfgr.
- Aurangabad, Maharashtra, India