DIPPING SOLUTION FOR USE IN PRODUCTION OF SILICEOUS FILM AND PROCESS FOR PRODUCING SILICEOUS FILM USING THE DIPPING SOLUTION
This invention relates to a dipping solution used in a process for producing a siliceous film. The present invention provides a dipping solution and a siliceous film-production process employing the solution. The dipping solution enables to form a homogeneous siliceous film even in concave portions of a substrate having concave portions and convex portions. The substrate is coated with a polysilazane composition, and then dipped in the solution before fire. The dipping solution comprises hydrogen peroxide, a foam-deposit inhibitor, and a solvent.
1 . A dipping solution in which a substrate coated with a polysilazane composition is dipped before fired in a process for producing a siliceous film; comprising hydrogen peroxide, a foam-deposit inhibitor selected from the group consisting of an alcohol, a surfactant and a mixture thereof, and a solvent other than said alcohol.
2 . The dipping solution according to claim 1 , wherein said alcohol is a monool, diol or triol derived from a saturated hydrocarbon containing 1 to 3 carbon atoms by replacing hydrogen atoms therein with 1 to 3 hydroxyls.
3 . The dipping solution according to claim 1 , wherein said alcohol is selected from the group consisting of methanol, ethanol, n-propanol, iso-propanol, and a mixture thereof.
4 . The dipping solution according to claim 1 , wherein said surfactant is a nonionic surfactant.
5 . The dipping solution according to claim 4 , wherein said nonionic surfactant is polyoxyethylene alkyl ether.
6 . The dipping solution according to claim 1 , wherein said solvent other than said alcohol is water.
7 . A process for producing a siliceous film, comprising
a coating step, in which a substrate surface having concaved portions and convex portions is coated with a composition containing a polysilazane compound,
a dipping step, in which the coated substrate is dipped in a dipping solution according to claim 1 , and
a hardening step, in which the dipped substrate is heated so as to convert the polysilazane compound into a siliceous film.
8 . The process according to claim 7 for producing a siliceous film, further comprising the step of preliminarily heating the substrate between the coating step and the dipping step.
9 . The process according to claim 7 for producing a siliceous film, wherein the substrate is heated in the hardening step under an inert gas or oxygen gas atmosphere containing steam in a concentration of 1% or more.
10 . The process according to claim 7 for producing a siliceous film, wherein the substrate is heated in the hardening step at a temperature of 400° C. to 1200° C.
11 . The dipping solution according to claim 1 , wherein the hydrogen peroxide is in the range of 30 to 60 weight % of the total amount of components.
12 . The dipping solution according to claim 1 , wherein the hydrogen peroxide is in the range of 30 to 35 weight % of the total amount of components.
13 . A dipping solution in which a substrate coated with a polysilazane composition is dipped before fired in a process for producing a siliceous film; comprising hydrogen peroxide, an alcohol, and a solvent other than said alcohol.
14 . The dipping solution according to claim 13 , wherein said solvent other than said alcohol is water.
15 . The dipping solution according to claim 13 , wherein the hydrogen peroxide is in the range of 30 to 60 weight % of the total amount of components.
16 . The dipping solution according to claim 13 , wherein the hydrogen peroxide is in the range of 30 to 35 weight % of the total amount of components.