| 摘要 |
PROBLEM TO BE SOLVED: To obtain a plated steel sheet excellent in corrosion resistance by laminating substantially >=2 layers of dendrite in the thickness direction of a plated film having a specified content of Al. SOLUTION: Al is incorporated by 20-95 wt.% into a plate film. The coated weight of the plated film is adjusted to >=45 g/m<2> per one side, and a chemically treated film is preferably formed on the surface of the plated film or a coating film on the surface. The chemically treated film is a chromate film formed by applying a chromating soln. contg. chromic acid with the weight ratio of Cr(VI) to total Cr adjusted to 0.3-1.0 and drying the soln., and the coated weight of the chromate film is adjusted preferably to 3-80 mg/m<2> , expressed in terms of metallic chromium. Since >=2 layers of dendrite are laminated in the thickness direction of the plated film, an intricate path is formed until the dendritic gap is extended from the film surface to the boundary alloy layer to suppress the progress of corrosion, and excellent corrosion resistance is stably obtained.
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