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Embrittlement Relief

 

Dear Metal Finishing Experts,

I have a customer that requires we electroless nickel, watts nickel and then black nickel plate. My question is do we need to bake the parts at 375 °F for three hours after the final finish, or do we bake the part in between plating for Hydrogen embrittlement relief. Example: Electroless Nickel then bake, watts nickel then bake. Or do we bake after the final finish. I think that the way to go is to bake after the final finish. Please let me know if you have any ideas or suggestions.

Thanks,

Andrew Boussarath
- Los Angeles, California, USA

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You did not say what the substrate is. That makes more difference than anything else. You can get away with a lot if it is cold rolled steel and can not get away with much if it fully hardened spring steel used in a failure critical application.

EN that has been heat treated is not easy to activate and to activate evenly, so I would avoid that if at all possible.

My personal thought is to come out of the EN tank, a quick rinse and immediately into the watts tank and then immediately rinse and into the black tank. This is normally considered as one plating process with multiple steps. EN in the AM and watts in the PM would not qualify. If it is exposed to air for a minute or so, you will probably have to go back thru the activation process also. Possibly slightly longer if it is misted to keep it totally wet during the transfer steps. Nickel passivates quite rapidly when you do not want it to. What ever your customer demands is what you will end up doing.

James Watts
- Navarre, Florida