The authoritative public forum
  for Metal Finishing since 1989
  

  -----

Nickel plating peels off after pressing

February 25, 2009

I work for a connector assembly company, who's a buyer of a kind of nickel-plated component. Recently, IPQC found that the plating of this component was peeling off after being pressed. ( this V-shape component will be pressed to O-shape in our process). This hasn't happened before, and as far as we can see, no change has been introduced to our process/equipment, all we know is that the plating supplier has changed the plating spec. - from "3 microns min of Nickel" to up to "0.5 micron copper under 7 microns max Nickel".

* The components appear well before being pressed.

Please can some experts help me out? :

a) Could the process/equipment be the root cause of the peeling-off of the plating?
b) I ever heard of that the thicker the plating is, the more brittle the plating would be. Is this correct? If so, is there any identified correlation between the thickness and the brittleness?
c) If the air pressure of the press could be the "killer" to the plating, what would be the needed pressure to "crack" the plating in the given circumstance (say 23 Centigrade and 60% humidity)?
d) It's said that if the plating cannot extend with the base material synchronously during press, the plating could be "cracked", is this could be one of the causes to this very issue?

Sorry for this series of questions, hope you experts could kindly advise.

Million thanks!

Eric HWANG
BUYER - Dongguan,Guangdong,China

It is evident that when the supplier of the plated parts changed the specs the problem began. Even at 7 micron thickness you should not be seeing cracking. What type of Ni bath is the supplier using? If it is electrolytic Ni plating, I would hope it would be Sulphamate Ni with low stress properties. Please find out and let us know.

Mark Baker
Fellow Plater - Syracuse, N.Y., USA
March 4, 2009