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  for Metal Finishing since 1989
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Bubbled plating?

In our plating shop we just started using nickel hardened gold on some of our strip lines. We have always used it on our barrel lines. My question is on one or more lines we keep getting a persistent peeling problem. The catch is that they do not start peeling for about 2 days. We do scheduled line maintenance every week. We change the cleaner and acid on the lines that have this issue twice a week. Any info would be great.

Matt Malloch
Electroplater - New Albany, Indiana, USA
2004

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First of two simultaneous responses --

I assume your cleaners and acid pretreatments are the correct ones of the strip material. Changing the cleaners and acid twice a week seems a bit excessive to me, but you know your process. Personally I would check the rinse waters between the stages to make sure there is no contamination between the cleaning stages. If the water is contaminated, no amount of changing the cleaners will solve the problem. I would suggest that all rinse waters are as pure as possible (i.e., de-ionised or at least softened) and that there is an oil trap in the water supply pipe. You may also like to check for contamination falling off the ceiling or overhead pipes.

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

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Second of two simultaneous responses --

You haven't given enough info to make a good guess. What kind of cleaner, what kind of acid, temperatures, concentrations, times, etc. would be needed to make a recommendation. I would hazard a guess, though, that the contact times in your strip line are less than those in your barrel line.

Another thing you might look at is a difference in nickel deposit stress. Given that you have a 48 hour delay in deposit peel, I would ask is it the nickel or gold deposit that peels.

James Totter, CEF
- Tallahassee, Florida
2004