Why it is important to remove oxides from a surface that is going to be plated?
Q. This may sound like a dumb question, but I would like to know why it is important to remove oxides from a surface that is going to be plated. Various people have told me that the oxide is nonconductive, is brittle and/or bonding between the surface layer and the plated layer is weak or nonexistent. A little explanation would be appreciated. P.W.J.
A. Your question is not a dumb one. In many aspects of our lives, statements are accepted without question. Electroplating and metal finishing is no exception. The reason oxides are removed from surfaces to be plated is to form active sites on the surface so that the subsequent deposit will bond properly.
The strongest bonding mechanism involves bonding through the outermost electrons in the surface atoms. If these atoms have their bonding sites occupied by oxides, the bonds cannot form.
The second bonding mechanism is a mechanical or interlocking type of bond. Bonds of this type are not as strong as those formed by the outermost electrons of atoms.
In certain cases, the only type of bonding that can be achieved is mechanical bonding. This type of bonding, while adequate in some applications, is not acceptable in most cases.
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