Summary for nickel foil adhesion Discussion
Electroformed nickel foil peels off mandrel too easily because the stainless steel 304 mandrel is likely becoming more passivated with repeated use, reducing adhesion over time. Ravinder Singh asked why nickel plated directly on SS304 loses adhesion after about 8 to 10 cycles and whether the steel changes in the electrolyte. The answerer noted that stainless steel naturally carries a chromium-oxide passive layer, so direct metal deposition on it usually has poor adhesion from the start. They said it is plausible that repeated plating and stripping further thickens the oxide/passive film, making adhesion progressively worse. The practical advice was to stop relying on direct deposition and instead properly prepare the stainless surface and use a nickel strike to promote bonding. The thread does not discuss a specific substitute material, but it clearly points to surface preparation as the key fix.
Q. We have been plating Nickel direct on SS304, for the last many years. But I could not understand
something: after coating about 8 to 10 times the adhesion reduces to nil. Please let me know why? Does the property of the SS304 change in the electrolyte after 8 to 10 times of working (we plate, and then peel to form a foil). Any other better substitute, please advise.
Ravinder Singh
– Gurgaon, India
September 5, 2012
A. I am surprised it takes 8-10 goes to get no adhesion! Stainless steel usually has a passive layer of chromium oxides on it, so any direct deposition of metal will have poor adhesion. I assume you do no pretreatment of the stainless steel, so I expect the oxide layer to increase in thickness and the degree of steel passivation to increase. Hence, you are broadly correct in thinking that the stainless steel surface does change with multiple use. If you want good adhesion, you need to prepare it and use nickel strike.
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
September 12, 2012
A. Perhaps it is not the stainless steel mandrel but a contaminated or un-balanced nickel solution instead.
G. Marrufo
Guillermo Marrufo
Monterrey, NL, Mexico
September 18, 2012