| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing an environment adaptive surface treated steel sheet which does not comprise hexavalent chromium harmful for the human body and environment at all, and in which corrosion resistance and blacking resistance are consistent. SOLUTION: When a film is formed on the surface of a galvanized steel sheet for improving its corrosion resistance, the galvanized steel sheet is subjected to cathode electrolytic treatment with a treatment liquid comprising: one or more kinds of vanadium compounds having a tetravalency; nitric acid or a nitrate; or further a metallic compound containing metal selected from Y and La. By performing the electrolytic treatment, the surface of the galvanizing film is oxidized and made inert, and a barrier film essentially consisting of a vanadium compound is formed on the surface of the steel sheet; thus both of its corrosion resistance and blacking resistance are improved. COPYRIGHT: (C)2008,JPO&INPIT
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