Metal finishing Q&As since 1989
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Electroless nickel plating of Monel
Q. Is it possible to electroless nickel plate Monel?
Mark ChandlerMusical instrument repairer - Yorkshire, UK
June 14, 2018
A. Hi Mark. Any plateable metal can in some fashion or other be deposited onto any substrate whatsoever, including rock, paper, and scissors.
But the most pressing issue is usually whether sufficient adhesion can be obtained for the demands of the application. And another important issue is often whether intermediate plating layers are permissible. If you need electroless nickel deposited directly onto Monel with good adhesion, I suspect that it is not possible both because nickel is such a passive surface that you won't get it activated without an intermediate layer like a nickel strike, and because Monel is known for 'coppering' (the surface getting an immersion deposit of copper during pickling, with the copper not being a catalytic surface for electroless nickel).
Hopefully we'll hear from someone who has actually done electroless nickel on Monel and can give us some details and limitations. But in the meanwhile it would help if you told us what it is you are trying to plate onto and why. Good luck.
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
June 2018
Q. Thanks Ted. I am in the UK and repair brass musical instruments such as trumpets, etc. Often an instrument can be in good condition but the valves have worn out and let air past, making the instrument unplayable. Some instruments have nickel onto brass valves, some modern instruments have stainless steel valves and some valves are Monel.
In a number of cases it will be necessary to plate the valve base surface to bring the valve up to the size of the honed casing (not looking at stainless steel valves, just brass and Monel). My local platers suggested using copper as the build up layer, so it is interesting that you say copper will not be good. Many original valves were nickel plated direct onto the brass valves - or so it appears.
In some cases the plating will just need to be .002" thick and in others up to .004" - the plated valves will need to be lightly finished honed or lapped to a close sliding and very smooth fit.
Have you any suggestion as to what can be used as a strike layer on the brass and Monel valves or a build up layer on valves that are more worn?
- Huddersfield, West Yorkshire, UK
June 25, 2018
A. Hi Mark. Thanks!
I didn't mean that copper plating "will not be good" -- it's probably actually required for your brass valves. I said that copper is not a catalytic surface for electroless nickel. That means electroless nickel will not spontaneously deposit on it … but this is not a problem for your particular application and is easily solved by 'sparking' (applying electricity for a few seconds to get a quick deposit of nickel, which is catalytic for the continued deposition).
Your platers can certainly try to activate the Monel via an electrolytic nickel strike, and follow this with the electroless nickel plating. There are many reports of poor adhesion and spotty off-and-on adhesion on Monel though, so if you can find a shop with actual experience in plating onto Monel, as opposed to simply a willingness to try it, it would probably be worth the hunt and the shipping charges :-)
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
June 2018
Thanks for the advice. I will definitely talk to some more platers.
- Huddersfield, West Yorkshire, UK
June 25, 2018
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