RoHS-compatible Electroless nickel on copper alloys

I have a client job shop that is having a problem with lead and cadmium free electroless nickel on copper alloys such as brass. Plating starts then stops after a short period of time. this problem does not occur with more conventional electroless nickel solutions.

I'm surprised that the plating even starts in the first place, Bert. Copper and brass are not catalytic to electroless nickel as far as I know. You need to apply electricity to start it; maybe they just need to hold the electricity on for a few seconds as they immerse the parts, rather than a quick spark?

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

I agree with Ted, you need an electrolytic layer between the copper and the EN,no matter whether it complies with RoHS or not.
I prefer a nickel strike layer.

Thanks, Ted and others for responding. We do start the plating with an aluminum alloy rod (2024 or 6061) to get the electrical activation. As the EN plating builds up on the brass, it becomes irregular in patches,and loses brightness. We do not have this problem with conventional, non-RoHS proprietary baths.

Have also tried electrolytic nickel strike with same results. We are going to try a dash of science using a measured voltage and time.

Will let you know.

Bert Sherwood

P.S. Nice hearing from you Ted. We are out here in LA in a state of dormancy.

Sorry I didn't see you at Sur/Fin, Bert. The RoHS baths are definitely different than conventional baths because they do not have lead and cadmium as regulators and "poisons"; but I'm afraid that I don't know how to fix them if the process worked fine with non-RoHs baths.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

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