Method of making an anodic phosphate ester duplex coating on a valve metal surface
US5102507A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 16, 1989 |
| Grant date | Apr 7, 1992 |
| Priority date | — |
| Expiry date | Oct 16, 2009 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC25D11/02
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A process is disclosed for treating the surface of a valve metal such as aluminum to form a two layer protective coating thereon using an anodizing bath consisting essentially of an aqueous solution having a concentration ranging from about 0.001 molar to a saturated solution of a phosphorus-containing compound selected from the class consisting of a phosphorus acid ester and salts thereof. A non-porous barrier valve metal oxide layer is formed on a surface of the valve metal, and a functionalized layer comprised of a phosphate ester is formed on the oxide layer. The functionalized layer protects the oxide layer against chemical attack by the electrolyte during anodizing
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.