Nonchromate metallic suface-treating agent, method for surface treatment, and treated steel material

Abstract

The present invention has for its object to provide a nonchromate metallic surface-treating agent which is suited for metallic substrates, and despite the absence of chromium therein, is capable of imparting high processability and corrosion resistance in preparation for a coating or other procedure. This invention provides a nonchromate metallic surface-treating agent which comprises, in each liter thereof, (a) 0.01 to 100 g/l of a silane coupling agent and/or a hydrolytic condensation product thereof, (b) 0.05 to 100 g/l of water-dispersible silica (as solids), and (c) 0.01 to 50 g/l, in terms of Zr ion, of a zirconium compound and/or 0.01 to 50 g/l, in terms of Ti ion, of a titanium compound and/or (d) 0.01 to 100 g/l of a thiocarbonyl-containing compound and/or (e) 0.1 to 100 g/l of a water-soluble acrylic resin.

Dependencies are inferred from the claim text.