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Nickel plating before Acid Copper Plating on SteelOctober 24, 2016
Q. I have a number of components that I would like to perform a functional (not aesthetic) finishing of copper plate on. The components will be used as welding fixtures in my shop with a substantial amount of MIG welding done around them and the copper plating is intended to reduce splatter adherence to the components. I read a post on this forum that functional copper plating would require a base plate of nickel. Copper plate would be done using a copper sulfate bath with pure copper sheet anodes. For the nickel, I've been trying to find good information on plating baths. I have a laboratory grade power supply (overcurrent protected, 30v 50 amp), enclosed fume hood (used for titanium welding, but with full carbon filtration), chemical disposal would be done through evaporation with solids being delivered to my county disposal service (already validated with them that they accept dry plating chemicals in reasonable quantities.
I have contacted multiple professional plating shops in the area, however, their turn around times aren't feasible for the shop schedule (I produce new fixtures often and they are usually slated to be used within two days). The shortest turn around time provided was 10 working days and with additional surcharges for small quantity plating.
Wondering what the process would be for a base nickel plate prior to copper plating. On the chemical front, I already have laboratory grade Nickel Ammonium Sulfate Hexahydrate on hand. What would the recommend bath composition and process?
I do have a copy of ASM Handbook Vol. 5: Surface Engineering on order. I do quite a bit of other finishing in my shop (cerakote, vitreous enamel, Parkerizing, anodizing (Ti and Al), and others.
Thank you in advance,
Job Shop owner and operator - Woodinville, Washington USA
^- Privately contact this inquirer -^
A. Hi Rama. Intermediate layers of plating between the substrate and the top layer may be applied for various reasons. To my knowledge the reason for applying nickel plating to steel before acid copper plating is simply to allow for adhesion (copper sulfate tends to immersion deposit onto steel, making good adhesion of acid copper plating directly on steel difficult or impossible).
Thus, I don't think the exact type of nickel plating is critical, nor the current density at which you apply it. Although we invariably recommend hooking up with a plating process supplier rather than attempting home-brew, I think almost anything, from a Wood's Nickel Strike to a semi-bright Watts Nickel plating will probably do. Nickel plating goes passive quickly though, so you should go directly from nickel plating to acid copper plating, with only a quick stop for rinsing.
I'd probably avoid the nickel ammonium sulphate, however, because ammonia will complex copper, making efficient waste treatment and removal difficult.
Ted Mooney, P.E. RET
Pine Beach, New Jersey