Metal sheet treatment method for reducing blackening or tarnishing during the storage thereof and metal sheet treated with this method
US10612144B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 4, 2014 |
| Grant date | Apr 7, 2020 |
| Priority date | — |
| Expiry date | Sep 15, 2036 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC25D7/0614
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
The present invention provides a metal sheet including a steel substrate coated on at least one face with a coating including from 0.1 to 20% by weight of magnesium, optionally from 0.1 to 20% by weight of aluminum, the balance being zinc, potential impurities linked to the method and optionally one or more additional elements selected from among Si, Sb, Pb, Ti, Ca, Mn, Sn, La, Ce, Cr, Ni, Zr and Bi, the content by weight of each additional element being less than 0.3%. The coating itself is covered by a layer, based on zinc hydroxychloride, having a chlorine coating weight of at least 1 mg/m2. The layer does not include hydrozincite or mixed hydroxycarbonates of zinc and aluminum or water-soluble compounds of sodium or potassium. The present invention also provides a method to obtain the metal sheet.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.