| 摘要 |
PROBLEM TO BE SOLVED: To provide a non-chromate based surface treated steel sheet which has corrosion resistance equal to or above that of a chromate treated steel sheet, and has a coating film adhesion even to an organic film as a coating substrate. SOLUTION: This surface treated steel sheet having excellent corrosion resistance is obtained by forming a surface reforming layer containing Al, Si and P on a galvanizing layer in a galvanized steel sheet. The mass ratios between Al and Si, and between P and Al in the surface modifying layer satisfy the relations in the following inequalities (1) and (2): 0.10<[Al%]/[Si%]<3.0 (1), and 0.90<[P%]/[Al%]<2.0 (2). COPYRIGHT: (C)2004,JPO
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