Delamination at copper/steel interface

I have a CRS 1010 part (3-sided box) that is plated with copper, bright nickel, black nickel, and passivated. The plating peels off of the steel on a couple of the parts we have received. The plating looks great, with no obvious blisters or other defects, it just peels off like foil.

My current suspicions are that the parts sat too long in the rinse tank prior to copper plate, or rectifier ripple in the copper tank (?)

Any thoughts?

Gail, lots of possibilities.

1. The part was not cleaned well enough. Possibly a silicon cutting fluid? Tank not hot enough, Tank too weak. Too short a soak time. 2. Not properly activated. Acid weak, cold, too short a time. 3. Passivated by delays in getting to the copper tank. 4. You did not say STRIKE! Steel has to get a copper strike then copper plate or it will immersion plate and peel like a banana. If it was struck, I would guess that the tank is out of balance (not enough cyanide or the goody if you are using pyrophosphate).

Gail,

It is necessary to know peel starts from where, from substrate, from copper or from bright nickel. Then you can figure out what's the problem you have.

Ling

James,

We are looking at a number of the possiblities you have mentioned. We have since found that most of the parts manufactured in this lot have some peeling.

The cleaning is done on an adjacent line that preceedes a zinc plating process; there have been no reported problems with zinc products.

Is a strike necessary with alkaline copper? That is what is being used (sorry for not telling you earlier.)

Do you know if rectifier problems could cause this sort of peeling?

Thanks for your response,
Gail