Corrosion-resistant surface-coated steel sheet
US5330850A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 28, 1992 |
| Grant date | Jul 19, 1994 |
| Priority date | — |
| Expiry date | Dec 28, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/12799
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A surface-coated steel sheet having improved corrosion resistance and suitable for use as automobile inner and outer panels comprises a steel sheet having on at least one surface thereof a composite coating which comprises the following layers (a) to (d) from the bottom to the top of the coating: PA0 (a) a first zinc alloy plating layer with a coating weight of 10-100 g/m.sup.2 which contains at least one of Ni and Co in an amount satisfying the following inequality: EQU 0.05.ltoreq.(5.times.Co)+Ni.ltoreq.10 (in weight percent), PA0 (b) a second zinc alloy plating layer with a coating weight of 0.05-10 g/m.sup.2 which contains at least one of Ni and Co in an amount satisfying the following inequality: EQU 10<(5.times.Co)+Ni.ltoreq.40 (in weight percent), PA0 (c) a chromate film layer with a coating weight of 20-300 mg/m.sup.2 as Cr, and PA0 (d) an organic coating layer with a thickness of 0.2-5 .mu.m.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.