PRODUCTION OF TITANIUM DIOXIDE COATING FILM

摘要

PROBLEM TO BE SOLVED: To form a titanium dioxide coating film having high adhesion to a substrate and high hardness without carrying out heat treatment. SOLUTION: An additive allowing equilibrium represented by the formula SiF6 <2-> +2H2 O→or←SiO2 +4HF+2F<-> to proceed right side is added to an aq. soln. contg. hexafluorosilicon complex ions to prepare a soln. contg. silicon dioxide. A silicon dioxide coating film 3 is formed on the surface of a substrate 2 by bringing the substrate 2 into contact with the soln. contg. silicon dioxide. An additive allowing equilibrium represented by the formula, (NH4 )2 TiF6 +2H2 O→or←TiO2 +4HF+2NH4 F to proceed right side is added to an aq. soln. contg. ammonium titanofluoride to prepare a supersaturated soln. contg. titanium dioxide. The objective titanium dioxide coating film 5 is formed on the surface of the silicon dioxide coating film 3 by bringing the substrate 2 into contact with the soln. contg. titanium dioxide. The silicon dioxide coating film 3 having high adhesion is interposed between the titanium dioxide coating film 5 and the substrate 2.