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The effect of pH on plating

Can anyone describe the affect that pH has on the plating process? I am researching for a chemistry a level. Any sources of information will be very helpful.

Thanks,

David F.
student - Reading, UK
2004

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Our "must have" booklist will cover the subject in reasonable detail for various different plating solutions. Some plating solutions are acidic, some are almost neutral, some are alkaline. Regardless, they won't operate properly if the pH is out of range for a wide variety of reasons: the metal may not stay in solution; excess acidity or alkalinity can harm the brighteners and other organics; pH out of range can neutralize the solvent (ammonia for example), the anodes may not dissolve correctly at the wrong pH, etc.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2004

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There is no simple answer. Some electroplating baths operate at high pH, so at low and some in the middle. Any deviation from their optimum will result in a loss of efficiency and even the bath not doing anything. Generally, if the pH is too low, you will start to codeposit hydrogen and for multifarious reasons, that is bad news. If the pH is too high, the cation (metal ion) could form hydroxides, which may or may not be soluble. I suggest you search for a basic electroplating book and even ask the Institute of Metal Finishing in Birmingham for advice and guidance. I would also suggest you concentrate on one or two specific and simple metals as this will make your project easier to keep under control. Try nickel and copper, for instance.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2004