Treatment of galvanized steel
US4756805A · kind A · utility
7Cited by
4References
4Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Oct 14, 1986 |
| Grant date | Jul 12, 1988 |
| Priority date | — |
| Expiry date | Oct 14, 2006 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC25D11/38
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A method of treating a zinc plated steel surface provides improved corrosion resistance and painting properties. The surface is rendered cathodic in the presence of an aqueous treatment liquor containing 5-70 g/l of hexavalent chromium, 0.01 to 5 g/l of trivalent chromium, 5-100 g/l of silica and/or silicate and 0.05-10 g/l of nitrate in which the ratio of Cr.sup.3+ /Cr.sup.6+ is within the range 1/50-1/3.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.