| 摘要 |
PROBLEM TO BE SOLVED: To provide a metallic surface treatment method which is adequate for metals, more particularly galvanized steel sheets, does not contain chromium in a metallic surface treating agent and is capable of imparting excellent workability and corrosion resistance to the steel sheets. SOLUTION: This metallic surface treatment method consists in treating the metal clad steel sheet with a non-chromate metallic surface treating agent containing specific ratios of (a-1) a silane coupling agent and/or its hydrolysis condensate, (a-2) water dispersible silica and (a-3) a zirconium compound as zirconium ions and/or titanium compound in one litter of the metallic surface treating agent and drying the steel sheet, then applying a rust preventive coating agent containing specific ratios of (b-1) the silane coupling agent and/or its hydrolysis condensate, (b-2) the water dispersible silica and (b-3) at least one kind of phosphorus-containing ions selected from phosphoric acid ions, phosphorous acid ions and hypophosphorous acid in one litter of the an aqueous resin solution or water dispersion of the resin. |
