Patent ID: 11926899
Assignee: RAYTHEON COMPANY
Field: Surface technology, coating (Chemistry)
Classification: CPC C | IPC C

Claim 16:
17. A process for coating a surface of an aluminum containing material, comprising:
degreasing a surface of an aluminum containing material in an immersion tank for 5-10 minutes at a pH of 9-11 and temperature of 110-150 F (43-66 C) to produce a degreased surface;
treating the degreased surface in a first high alkaline treatment immersion tank immediately subsequent to the degreasing to produce an alkaline treated surface having smut on the surface;
deoxidizing the alkaline treated surface having smut on the surface subsequent to the first high alkaline treatment;
treating the deoxidized and the alkaline treated surface in a second high alkaline treatment immersion tank immediately subsequent to the deoxidizing for 30 seconds-3 minutes at a temperature of 135-150 F (57-66 C), with a pH greater than 12; and
treating the aluminum with a hydrothermal treatment immediately subsequent to the high alkaline treatment for 20-60 minutes, wherein smut from the high alkaline treatment is not removed and the aluminum is directly subjected to the hydrothermal treatment immersion providing the surface of the aluminum containing material with a chromate-free coating.