Protective Internal Coatings for Porous Substrates

Abstract

A material contains open pores in which the channels and pores that are internally coated with at least one layer of phosphorus-containing alumina. Such material is formed by infiltrating a porous material one or more times with a non-colloidal, low-viscosity liquid coating precursor, drying, and curing the coating precursor to form a phosphorus-containing alumina layer within pores of the material.

What is claimed: 
     
         1 . A composition comprising:
 a material saturated with a non-colloidal solution of a phosphor-alumina precursor having an aluminum-to-phosphorous atomic ratio of 0.5:1 to 15:1;   the material saturated with the non-colloidal solution adapted to form a liquid film having a thickness of 5 to 250 nm on pore walls of a porous inorganic substrate; the liquid film consisting of the non-colloidal solution.   
     
     
         2 . The composition of  claim 1 , wherein the material is a cloth, a sponge, or porous material. 
     
     
         3 . The composition of  claim 1 , wherein the non-colloidal solution includes an alcohol solvent selected from the group consisting of methanol, ethanol, n-propanol, i-propanol, n-butanol, 2-butanol, t-butanol, and a mixture thereof. 
     
     
         4 . The composition of  claim 1 , wherein the phospho-alumina precursor has an aluminum-to-phosphorous atomic ratio of 4:1 to 15:1. 
     
     
         5 . The composition of  claim 1 , wherein the liquid film is formed by liquid migration from the material into a pore structure of the porous inorganic substrate. 
     
     
         6 . A composition comprising:
 a saturated sponge adapted to maintain continuous contact of a non-colloidal solution of a phosphor-alumina precursor with a porous inorganic substrate thereby migrating the non-colloidal solution into a pore structure of the porous inorganic substrate.   
     
     
         7 . The composition of  claim 6 , wherein migrating the non-colloidal solution into the pore structure forms a liquid film having a thickness of 5 to 250 nm on pore walls of a porous inorganic substrate. 
     
     
         8 . The composition of  claim 6 , wherein the non-colloidal solution of the phosphor-alumina precursor has an aluminum-to-phosphorous atomic ratio of 0.5:1 to 15:1. 
     
     
         9 . The composition of  claim 6 , wherein the non-colloidal solution has a viscosity below 150 cSt. 
     
     
         10 . A composition comprising:
 a saturated cloth adapted to maintain continuous contact of a non-colloidal solution of a phosphor-alumina precursor with a porous inorganic substrate thereby migrating the non-colloidal solution into a pore structure of the porous inorganic substrate.   
     
     
         11 . The composition of  claim 10 , wherein migrating the non-colloidal solution into the pore structure forms a liquid film having a thickness of 5 to 250 nm on pore walls of a porous inorganic substrate. 
     
     
         12 . The composition of  claim 10 , wherein the non-colloidal solution of the phosphor-alumina precursor has an aluminum-to-phosphorous atomic ratio of 0.5:1 to 15:1. 
     
     
         13 . The composition of  claim 10 , wherein the non-colloidal solution has a viscosity below 150 cSt.