Summary for black plating resistant to 8% koh Discussion
black plating resistant to 8% KOH is the core issue in this thread: Steve Diprinzio of Sigma in Tucson asked for a black finish for stainless, aluminum, or steel fixture plates that would be dipped repeatedly for about 20 minutes at a time in 8% potassium hydroxide and needed to survive the caustic solution indefinitely. The reply notes that black precious-metal platings might be fully resistant, but could be too expensive for practical use. The answerer suggests black electroless nickel plating as a likely candidate because it can be applied to all three substrate types and may meet the service requirement. The reply also asks whether a metal plating is truly required, or whether a powder coating or plastisol could be considered instead, implying that non-metallic coatings might be worth evaluating if the application allows it.
Q. Hi,
I need a black plating process for either stainless, aluminum or steel plates which will become part of a fixture, which will dipped many times for extended periods (approx. 20 min)
in KOH (potassium hydroxide 8%). The plating needs to hold up to the caustic solution indefinitely.
Can someone offer suggestions??
Thanks
steve diprinzio
sigma – tucson, Arizona USA
October 11, 2017
A. Hi Steve. There are probably black precious metal platings which would be completely resistant, but they may be economically prohibitive. I would think that black electroless nickel plating might serve your needs, and it can be applied to any of those substrates. Must it be a metal plating rather than a powder coating or plastisol?
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
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October 2017