The present invention provides: a coating composition for forming a
titanium oxide film, comprising (A) a titanium-containing aqueous liquid
obtained by mixing at least one titanium compound selected from the group
consisting of hydrolyzable titanium compounds, low condensates of
hydrolyzable titanium compounds, titanium hydroxide and low condensates of
titanium hydroxide with aqueous hydrogen peroxide, and (B) at least one
halide selected from the group consisting of titanium halides, titanium
halide salts, zirconium halides, zirconium halide salts, silicon halides
and silicon halide salts; a process for forming a titanium oxide film,
comprising applying the coating composition to a metal substrate and
drying the resulting coat; and an undercoating material for metal
substrates and a post-treating agent for phosphate undercoats on metal
substrates, the material and agent being the above coating composition.
