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Skip plating in nickel plating

We have 200 lit of nickel solution. at the moment we encounter to skip plating. if we decrease pH to 0-0.5 we can plate but in higher pH we have the problem again.I am sure that in our solution we cave no chrome or other metal but the color of solution is changed and in temperature over 70 we have some impurities that come over the solution and can be removed with filter. I have no idea about this impurities but maybe it is created by decomposition of brightener. I would be thankful if help me.
thank you saeed,

Saeed Ghasemzadeh
- Iran
2007

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First of two simultaneous responses --

The normal reason for skip plate is an oil layer or a additive breakdown product floating on top of the tank. Carbon treat the tank and re add your brighteners and wetting agents IAW specifications.

James Watts
- Navarre, Florida
2007

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Second of two simultaneous responses --

Saeed,
Because you said the solution has changed color, I would suspect metallic or organic contamination. Chloride contamination is a possibility as well. Because I know little of your process, the solution to the problem may have to be a process of elimination. Dummy plate, carbon treat, analyze for chloride concentration. The pH should not be below 3.6 and higher than 4.5. Sounds like your nickel supplier should pay you a visit, or run some tests on the solution.

Mark Baker
Process Engineer - Syracuse, New York
2007

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Dear saeed,

I think you cannot just ignore the possibility of chrome contamination as well.Apart from what Mark suggested,I would add 100 ml of 5% solution of sodium bi sulphite,give low and High pH treatment to the bath.
Try to check carry over oil and grease.
Regards,

T.K. Mohan
plating process supplier - Mumbai, India
2007

Thank you for all of your response.I found that breakdown of our additives was creating this problem.But unfortunately I can not remove them with carbon treatment and filter. Can you recommend me how I can treat our bath and also I am looking for reason of this breakdown.I am suspected to anode box and titanium heater.

Saeid ghasemzadeh
- tehran-iran
2007

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I have never heard of a brightener breakdown that could not be removed with proper carbon treatment. I used carbon cartridges and sometimes bulk carbon in a special holder. Because you are removing all of the organics, it will overload the carbon. It very probably will require two or more cartridges run for 4 hours each. James Watts - Navarre, Florida I don't understand how a Ti basket and heater can be suspect with the problem you have. A hot peroxide / carbon batch treatment most times solves the problem you are having. Consult your Ni supplier or the tech data sheet for the bath regarding this process. Good Luck! Mark Baker Process Engineer - Syracuse, NY USA Dear sir, for treatment of your nickel solution follow this sequence.but before this first give your solution for complete analysis,to find reason of problems,& which impurities effect your bath. 1. heat up to 70 C, adjust pH up to 5.5 2. add hydrogen peroxide 2 ml/ltr 3. agitate bath for 4 hrs. at 70 °C 4. add activated carbon 2 gm/ltr 5. agitate for 4 hrs at 70 °C 6. stop agitation ,settle down all the carbon full night 7. filter above solution and dummy at lower PH & lower current density & check the dummy plate it is fully cover with nickel layer without any indication of impurities. then add brightener& additive and start plating. Vijay Parmar - Mumbai, Maharashtra, India Dear Saeid Ghasemzadeh, First thing don't go for higher temperature there may be break down of products due to higher temperature. You can refer The Canning Handbook [on eBay, Amazon, AbeBooks] for knowing more about treatment or talk to your chemical supplier. Vishwas Nangare motorcycle accessories mfgr. - Aurangabad, Maharashtra, India

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DEAR Vijay Parmar

VERY THANK YOU FOR YOU SUGGESTION.WE DID YOUR RECOMMENDATION AND SOLVE OUR SKIP PLATING. BUT THE MAIN REASON FOR THIS PROLEM IS UNKNOWN FOR US. BUT AT THE MOMENT WE UNDERSTAND THAT EVERY DAY AFTER OUR ONE DAY WORKING OUR PH DECREASE FROM 4.2 TO 3.6. PLEASE HELP US TO ELIMINATE THIS PROBLEM. ALSO DON'T YOU THINK THAT OUR SKIP PLATING IS CREATED FROM THIS .

SAEID GHASEMZADEH
asia dagheygh abzar - Tehran, Iran
2007