Chromate-free protective coatings
US5866652A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 27, 1996 |
| Grant date | Feb 2, 1999 |
| Priority date | — |
| Expiry date | Feb 27, 2016 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC23C2222/20
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
The invention provides chromate-free coating mixtures, and coatings formed from these mixtures, that protect an underlying aluminum or aluminum alloy substrate from corrosion. The coating mixtures include a continuous phase selected from organic polymeric compositions, or sol-gels, and a distributed phase, dispersed or dissolved throughout the continuous phase. The distributed phase includes the corrosion-inhibiting chromate-free salts. In accordance with the invention, the mixture of salts includes (1) a first salt selected from (a) the esters of rare earth metals, such as cerium and lanthanum oxalates and acetates, and (b) the vanadate salts of alkali and alkali earth metals, such as sodium metavanadate and calcium metavanadate; and (2) a second salt that is a borate salt of alkali earth metals, such as barium metaborate. In certain embodiments, the coatings of the invention include both (a), and (b), in conjunction with the borate salt (2). In other embodiments, the chromate free salt is a chloride of a rare earth metal, or mixture of such chlorides, either alone or in combination with the first salt or the second salt, or both the first and second salts. Coatings of the inventi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.