Anodizing of Beryllium

Question:

My company has a lot of positive experience with anodized aluminum. Recently, due to design requirements, we are now required to anodize beryllium and Albemet. Can you give some information on the type of process that should be used? Are you aware of any differences in durability and overall corrosion resistance between anodized aluminum and anodized beryllium and Albemet? G. P.

Answer:

Very honestly, I have not seen many installations that anodize these two materials. I know the process, at least for beryllium, is and has been performed as a production process. Typically, the process calls for the use of chromic acid and potassium dichromate.

One such process uses a solution of 6–7 oz/gal of chromic acid at 90–100 asf for 30 minutes and a temperature of 62 – 65oF. The resulting jet-black coating is said to offer outstanding corrosion protection as measured by the salt spray test and to offer excellent protection against high temperature oxidation. I do not have any information comparing beryllium and aluminum anodized parts. Perhaps one of our readers can help.

Regarding Albemet, an aluminum/beryllium alloy, I do not have any specific information.