| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface-treated steel sheet which has a film containing no hexavalent chromium thereon, has superior corrosion resistance, thermal discoloration resistance and blackening resistance, and further has excellent adhesiveness with an organic resin layer to be formed on the upper surface of the steel sheet. SOLUTION: The surface treatment composition (K) includes: a titanium-containing aqueous liquid (A) of 100 parts by mass in terms of a solid content, which is obtained by mixing a titanium compound such as a hydrolyzable titanium compound and a low condensate thereof with hydrogen peroxide water; a nickel compound (B) of 0.01 to 10 parts by mass with respect to the aqueous liquid (A); an aluminum compound (C) of 1 to 100 parts by mass; a fluorine-containing compound (D) of 1 to 800 parts by mass; and further silicon oxide (E) and metal phosphate (F) in the total amount of 20 to 90 mass% by a ratio to the whole solid content in the composition. The surface-treated steel sheet has the film with a coating weight of 0.1 to 2.0 g/m<SP>2</SP>on the surface, which has been formed by applying the surface treatment composition (K) onto the surface of a zinc-base plated steel sheet or an aluminum-base plated steel sheet, and drying the applied composition. COPYRIGHT: (C)2008,JPO&INPIT
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