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Marks and stains with the nickel plating baths

We are operating Nickel plating baths for several years but since 2-3 months it is giving some marks-stains on the jewelry .. could somebody please explain to me why this is happening and the details of chemical compositions in the bath and its functions.
thanx lot
Best Regards
Desh

Desh Ayas
plating shop employee - Sri Lanka
December 16, 2009

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Hi, Desh. Whole books have been written on the composition and operating conditions for nickel plating baths. There are at least four or five common baths, with a range of operating conditions and a host of possible generic and proprietary addition agents; I don't think the details of the various chemical compositions and the functions of all of the possible materials is a manageable question for a forum response.

But fairly simple chapters on the subject can be found in such texts as the Metal Finishing Guidebook, and if you are using a proprietary formulation then help should be available from the vendor.

Please send pictures of the stains, and the details of your operating conditions, and maybe someone will be able to spot something that sounds wrong. If nothing that you monitor has changed since the days when you were plating stain-free, it sounds like a contaminant that you don't monitor for. Good luck.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
December 16, 2009