Patent ID: 8603923

Claim:
A process for producing a fired siliceous film, comprising; i) a coating step, in which a substrate surface having concaved portions and convex portions is coated with a composition containing a polysilazane compound, ii) a dipping step, in which the coated substrate is dipped in a dipping solution comprising hydrogen peroxide, a foam-deposit inhibitor selected from the group consisting of 1 to 20 weight % alcohol, 0.1 to 20 weight % surfactant and a mixture thereof, and a solvent other than said alcohol, wherein the hydrogen peroxide is in the range of 30 to 60 weight % of the total amount of components, iii) a non-hardening heating step in which the dipped substrate is heated at a temperature lower than that of the hardening step temperature for a shorter time to produce a non-hardened polysilazane film, iv) a hardening heating step in which the non-hardened polysilazane film is heated at a higher temperature than the non-hardening step for a longer time to convert the non-hardened polysilazane film to a fired siliceous film.