COATED ZN-AL ALLOY PLATED STEEL SHEET EXCELLENT IN CORROSION RESISTANCE

摘要

PROBLEM TO BE SOLVED: To provide a coated Zn-Al alloy plated steel sheet excellent in corrosion resistance and coating film adhesion without relying on a chromate film, a Cr type rustproof pigment or the like.;SOLUTION: The coated Zn-Al alloy plated steel sheet is constituted by forming an undercoating film 4 compounded with a magnesium salt and/or a phosphate on a Zn-Al alloy plating layer 2 through a chemical forming film 3 containing a titanium compound and/or a zirconium compound. As the titanium compound or the zirconium compound, at least one of a compound selected from hexafluorotitanic acid, hexafluorozirconic acid and metal salts of them is used. The chemical forming film may be an organic-inorganic composite film containing an organic resin such as a phenol resin, an acrylic resin, an acrylolefin resin, a polyurethane resin and the like.;COPYRIGHT: (C)2005,JPO&NCIPI