refurbishment of hard chrome plating

[gcb]

I have been advised that, in order to refurbish a worn hard chrome plating on a component, I will have to completely remove the old plating and re-deposit a new one (i.e. onto base material). Is there any reason why the existing Cr surface cannot be activated and plated onto?

 

[Rich2001]

On the existing (old) chrome there is a thin invisible layer of chromium oxide. This layer adheres very tightly to the underlaying chrome protecting it. (The chromium oxid eis what make stinless stainless.) It also form very rapidily so if you were to remove it it would readily re-form.

The sequence looks like this:

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Chromium Oxide - 1 or 2 atoms thick
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Chromium several atoms thick
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Nickel

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Copper

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Base Metal