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Some shop problems in electroless nickel with teflon plating
Q. Presently I do nickel/teflon plating on small cylindrical parts. The plating is deposited all over with a .0002" thickness. The inside diameter varies between .047" to .090". The parts are made of 440C stainless steel and are subject to approx. 500 °F heat. The plating keeps peeling off from the inside diameter.
Lou Carozza- Miami, Florida
2005
A. My guess is you are not getting enough solution flow in that tiny ID for it to get clean or properly activated. I also doubt if you are getting much nickel plate in it either.
James Watts- Navarre, Florida
2005
A. Hi,
Well, your information is sparse. The surface which peels off, is it brittle? How do you plate the parts (racks, barrel etc.)?
Regards,
Dominik Michalek- Mexico City, Mexico
2005
A. 400SS as well as other series and tool steels have to be activated first in a high acidic chloride electrolyte before EN plating. This initial process is electrolytic as well as other prior cleaning steps, thus dependent on electrochemical laws, one of which indicates that very little or no current (therefore very little or no effect) will get into an inside diameter. This in turn means that, although EN will penetrate, it might plate on top of a surface that is not properly cleaned or activated. Few alternatives apart from selecting another base steel to my point of view.
Guillermo MarrufoMonterrey, NL, Mexico
2005
A. What is your cleaning process and what state is the stainless steel in? Has it been heat treated prior to plating? How are you plating the ID? What are your plating conditions? From the information you have given, I would initially think the problem could be inadequate cleaning or an incorrect current density. Have you considered electroless nickel/PTFE?
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2005
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Ed. note: Hmm. I and some other readers assumed that Lou was doing electroless rather than electrolytic nickel plating, Trevor. But you are right that he didn't say that.
Q. Hi from Spain,
I have a problem with a bath of electroless nickel PTFE. The coating is OK, but I can't eliminate the powder of PTFE that settles on the parts after the bath.
Normally this is not a problem, but I have a new parts from a new client that requires the eliminate of this precipitate. Now this parts are being covered by other supplier that is capable of eliminating this precipate.
Sorry for my poor english. I hope that the problem is understood well. Thanks for your prompt answers.
- Valencia, Spain
June 13, 2013
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