Plating Q&A: Can Electroless Nickel Tarnish?
Q. What can we do to minimize tarnishing electroless nickel deposits? While this does not happen every day, it occurs often enough to be a problem.
A. Electroless nickel tarnishing is not a common phenomenon. Start troubleshooting by reviewing your rinsing process, paying attention to the final rinse. The nickel concentration in the final rinse should be less than 20 ppm, and the pH must be around seven. EN is susceptible to tarnishing in an environment containing sulfur. Look to your chemical vendor for help in passivation of the EN deposit. Search PFOnline.com for current tarnish preventive treatments.
Originally published in the September 2015 issue.
The reasons for installing an in-house cold blackening system are many and varied.
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Applications, plating solutions, brighteners, good operating practices and troubleshooting.