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Electroplating Copper Chromium Alloy Deposit(-----)
(to provide context, hopefully helping readers more quickly understand the Q&A's)
It is far more often the case that you can't electrodeposit a given alloy than that you can :-(
Why? Consider for example a student's lemon battery where a copper penny and a zinc coated nail are inserted into the conductive lemon juice and connected. A voltage of about 1.0 volts is generated as the copper pulls electrons from the zinc, causing the zinc to lose electrons and turn from metal to positively charged ions that dissolve into the acidic juice.
Now imagine trying to electrodeposit brass (copper-zinc) in this electrolyte. No sooner would an atom of zinc plate out as metal, than a copper ion next to it would steal its electrons, turning the zinc atom into a positively charged ion which dissolves again ... so your electrodeposit will be almost pure copper instead of brass.
There are some complexing tricks that can make plating of certain alloys (including brass) possible, but in general it's tough and usually it's impossible.
Q. As a mechanical engineer, I am looking to electroform or produce a heavy deposit of Copper 0.5-1% Chromium alloy (AMS C81500). The result will be heat treated to improve its strength and annealing resistance. I know that both copper and chromium can be electroplated from H2SO4 electrolytes. Can they be plated simultaneously to produce an alloy? Or will an attempt work like a tank house and produce electrolytically refined copper?
I would prefer to produce AMS C18000 but I suspect that electroplating the Si will be impossible.
- Colchester, Vermont
A. Hi John. I strongly suspect that this is impossible. A quick scan of Brenner's 2-volume 1350-page tome on Electrodeposition of Alloys didn't seem to show anything promising, but if you can get to a library that has it, and if you have the time & inclination, it covers absolutely everything about electrodeposition of alloys :-)
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey