Dipping solution for use in production of siliceous film and process for producing siliceous film using the dipping solution

Abstract

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.