Chromate treatment of a metal coated steel sheet
First Claim
Patent Images
1. A method for treating a metal coated steel sheet, comprising:
- subjecting a metal coated steel sheet to a cathodic electrolytic treatment, to form a cathodically electrolytic chromate film thereon, in a bath of a composition containing (1) Cr6+ ions, (2) ions of at least one element selected from the group consisting of Zn, Ni, Co, Al, Mg, Sn, Mn and Pb, and (3) at least one additive selected from the group consisting of PO43- ions, a fluorine compound, silica and a silicate, andimmediately subjecting the resultant steel sheet to an anodic electrolytic treatment in a bath of said composition to convert said cathodically electrolytic chromate film and further to form an anodically electrolytic chromate film thereon.
1 Assignment
0 Petitions
Accused Products
Abstract
A chromate treatment of metal coated steel sheets comprising subjecting the sheets to a cathodic electrolytic treatment to form a chromate film thereon and subjecting the sheet to an anodic electrolytic treatment to form an anodic electrolytic film on the chromate film and to convert the chromate film. The treatment is applicable to various metal coated steel sheets, such as those coated with zinc, zinc alloy, aluminum, aluminum alloy, lead and lead alloy, and is effective to improve the corrosion resistance of the sheets, the quality of paint coating applied on the sheets and the adaptability of the sheets to a cation electro-deposition paint coating.
7 Citations
9 Claims
-
1. A method for treating a metal coated steel sheet, comprising:
-
subjecting a metal coated steel sheet to a cathodic electrolytic treatment, to form a cathodically electrolytic chromate film thereon, in a bath of a composition containing (1) Cr6+ ions, (2) ions of at least one element selected from the group consisting of Zn, Ni, Co, Al, Mg, Sn, Mn and Pb, and (3) at least one additive selected from the group consisting of PO43- ions, a fluorine compound, silica and a silicate, and immediately subjecting the resultant steel sheet to an anodic electrolytic treatment in a bath of said composition to convert said cathodically electrolytic chromate film and further to form an anodically electrolytic chromate film thereon. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
Specification