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Is it possible to put a bias to improve the PVD on pieces powder coating?

I have some problem of chromium adherence (deposited by sputtering DC) on pieces made of aluminum and coating with epoxy powder.

I have a DC generator that I don't use, it was possible rather than to let the pieces in the ground, to plug them to this generator to improve the deposition (bias)? but as they are covered of epoxy, it is not anymore conductive! is what I am going to have an effect ?

Thank's
Gigi

DJ Gigi
plating shop - Switzerland
2005

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The answer to your question is both yes and no. While your surface is insulating, as soon as you begin to coat it will become a conductor, and so you can bias the parts with your generator. However, it might not help. The value of biasing depends on the plasma density surrounding your parts. If you have little or no plasma, the bias is useless. If you are using a balanced magnetron for your sputter source, you probably don't have a great deal of plasma from the source reaching your parts. This means you might have to create the plasma near the parts by raising the voltage on the bias high enough to ionize the gas in the chamber near the parts (glow discharge ionization). How high depends on system geometry.

Jim Treglio - scwineryreview.com
PVD Consultant & Wine Lover - San Diego,
California
2005