Identification please for my new CMP

[Chris Suslowicz]

Originally Posted by Keith Webb

I don't know what the process is to make those black and silver plates, but I know there are people who can reproduce that process.

Anodising, I think. The plate is coated with a protective layer (photoresist as used for making printed circuit boards for small runs, or printed with a waterproof coating for mass production) where it needs to remain silver, then put in a chemical bath with a dye and connected to the positive supply. The electrolytic action etches the surface of the plate where it's in contact with the solution, and the dye is absorbed by the layer of aluminium oxide the immediately forms.

Same process as used to produce coloured aluminium cookware, etc.





(More complex than I first thought: https://en.wikipedia.org/wiki/Anodizing .)

Chris