High temperature amorphous composition based on aluminum phosphate

Abstract

A composition providing thermal, corrosion, and oxidation protection at high temperatures is based on a synthetic aluminum phosphate, in which the molar content of aluminum is greater than phosphorous. The composition is annealed and is metastable at temperatures up to 1400° C.

1 . A high temperature stable composition comprising aluminum phosphate wherein the ratio of aluminum to phosphorous is greater than one-to-one, said composition being annealed and characterized by containing at least 50 percent by weight of an amorphous content, said composition being metastable of temperatures from ambient up to 1400° C.  
     
     
         2 . The composition of  claim 1  additionally comprising a substrate, said composition being a coating on said substrate.  
     
     
         3 . The composition of  claim 1  wherein said composition is in the form of a fiber.  
     
     
         4 . The composition of  claim 2  wherein said coating protects said substrate from oxidation at elevated temperatures.  
     
     
         5 . The composition of  claim 2  wherein said coating protects said substrate from corrosion at elevated temperatures.  
     
     
         6 . The composition of  claim 1  comprising an additional metal.  
     
     
         7 . An aluminum phosphate composition, said composition comprising aluminum phosphate wherein the amount of aluminum relative to phosphorous in said composition exceeds five percent, said composition being metastable at temperatures up to 1400° C.  
     
     
         8 . A method for protecting a substrate from corrosion and oxidation at elevated temperatures, said method comprising the steps of applying a precursor solution to said substrate, said precursor solution comprising phosphorous pentoxide and an aluminum salt, wherein the ratio of aluminum to phosphorous is greater than one to one, and thereafter drying annealing said solution on said substrate.