| abstract |
Provided is a surface treatment composition that does not contain hexavalent chromium at all, has excellent corrosion resistance, heat discoloration resistance, and blackening resistance, and has excellent adhesion to an organic resin layer formed as an upper layer. SOLUTION: At least one titanium compound selected from hydrolyzable titanium compounds, hydrolyzable titanium compound low-condensates, titanium hydroxide, and titanium hydroxide low-condensates is mixed with hydrogen peroxide. 10 to 300 parts by mass of the zirconium carbonate compound (B) and 50 to 200 parts by mass of the organic phosphate compound (C) with respect to 100 parts by mass of the solid content of the titanium-containing aqueous liquid (A) obtained by The metal phosphate (D) is 5 to 20 mass% in the total solid content of the surface treatment composition, and the silicon oxide (E) is 10 to 50 mass% in the total solid content of the surface treatment composition. contains. [Selection figure] None |