PURPOSE: To prepare the titled substrate coated with silicon oxide having high stability against saline water and high-temperature steam, by forming a silicon oxide coating film containing ZrO2 on the surface of a substrate.
CONSTITUTION: An alcohol solution containing 5W30wt% organic silicon compound (e.g. ethyl silicate) is added with a zirconium compound[e.g. ZrCl2, Zr(NO3)4, etc.]in an amount of 1W30mol% (as ZrO2), and the pH of the mixture is adjusted to 2W6 with an acid such as hydrochloric acid, acetic acid, etc. to obtain a film-forming solution. The solution is applied to the surface of a substrate made of glass, ceramic, plastic, etc., dried by heating, and baked in an oxidative atmosphere or in air at 300W650°C to obtain a silicon oxide coating film having a thickness of 500W2,000. The silicon oxide coating film thus obtained is resistant to the formation of spot defects and fine cracks even by the outdoor exposure.
IIDA NORIYUKI
MURAKAMI KAIMEIDO KK