I have a question: does anyone know whether the aluminum surface treatment Allodine 1200 can give rise to outgassing when used in high vacuum conditions ? As I understand it, it is a chemical deposition of CrO3 on the Al surface.
jim mcnamara
Jun26-08, 05:53 AM
Chromate conversion film on aluminum has very high corrosion resistance - e.g., salt spray resistance (provides 300+ hours resistance - ASTM-B117 I think), and in normal applications it is not recommended to be left unfinished. And yes, it is hexavalent Chromium.
I've never seen anything on chromate conversion films and high vacuum applications.
Unless you need corrosion resistant aluminum, consider another surface film treatment.
FredGarvin
Jun26-08, 08:10 AM
The MIL specs I deal with do not list anything except the application at low temps is not recommended. I'll hit up some of our materials folks to see if they know of anything about vacuum conditions.
By the way, Type II conversion coating does not contain hexavalent chromium, Type I does.