Corrosion protection for galvanized and alloy galvanized steel strips
US6537387B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jul 6, 2000 |
| Grant date | Mar 25, 2003 |
| Priority date | — |
| Expiry date | Jul 6, 2020 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC23C22/364
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A process for the corrosion protection of steel strips coated with zinc or zinc alloy, characterised in that the steel strips coated with zinc or zinc alloy are brought into contact with an aqueous treatment solution having a pH within the range of from 1.5 to 3.5, which contains 1 to 20 g/l manganese(II) ions and 1 to 150 g/l phosphate ions, and the solution is dried without intermediate rinsing. Optionally the solution may contain in addition: up to 10 g/l zinc ions, up to 10 g/l nickel ions, up to 20 g/l titanium ions, up to 50 g/l silicon ions in the form of silicon compounds, up to 30 g/l fluoride ions, up to 150 g/l of one or more polymers or copolymers of polymerisable carboxylic acids selected from acrylic acid, methacrylic acid and maleic acid, and esters thereof with alcohols having 1 to 6 carbon atoms. The present invention also relates to the correspondingly-treated metal strips.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.