Q. We manufacture nickel-plated components for various bathroom fixtures. These components are made of brass and plated with decorative bright nickel or chrome. In some cases, they are cut after plating, and most of the time this is done without any peeling of the plated surface. When peeling of the nickel does occur, it is along the cut edges and it typically exposes another layer of nickel. Our plating vendor has told us that if the bright nickel finish is not satisfactory a second layer of nickel is plated over it.
My question is: can nickel be plated on nickel without the problem of one layer separating from the other?—J.B.
A. Yes, nickel can be plated over nickel, and this is done all the time. The problem that you are experiencing is not unusual, and it has to do with proper adhesion of one nickel layer to the other. Nickel, when exposed to the atmosphere, forms oxides that protect the nickel layer and the base material. The drawback is that the oxides on the surface also prevent good adhesion of any metal plated over the nickel. What is required is removal of the oxides from the surface of the plated nickel layer, followed by immediate plating of the second layer.
The most foolproof way of preparing a nickel surface for subsequent plating is to use a Wood’s nickel strike. In less-severe situations, acids also may be used to prepare the surface. You can find additional information on this topic by searching PFonline.com.