| 摘要 |
PROBLEM TO BE SOLVED: To provide an aluminum-based plated steel sheet in which a chemical conversion coating obtained by further improving the corrosion resistance of a Cr-free chemical conversion coating and which has a self-repairing action is formed. SOLUTION: For the aluminum-based plated steel sheet, an aluminum-based plated steel sheet on which an Al-Si alloy plated layer is formed is used as a base material, and a chemical conversion coating containing a double compound of Ti and V is formed on the surface of the base material. The content of Si in the Al-Si alloy plated layer preferably lies within a range of 5 to 13 mass% as the whole of the plated layer, and is concentrated to 7 to 80 mass% in the surface layer of the plated layer. As the Ti and V double compound, oxide, hydroxide, phosphate, fluoride, organic acid or the like can be cited. The chemical conversion coating may contain one or more kinds selected from the group consisting of the oxide, hydroxide, phosphate, fluoride, carbonate and organic acid salt of Mn as well, and, if required, may further contain the phosphate, compound phosphate and/or a lubricant of Mn. COPYRIGHT: (C)2003,JPO
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