Coating fabrication method for producing engineered microstructure of silicate-resistant barrier coating

Abstract

A gas turbine engine article includes a substrate and a silicate-resistant barrier coating disposed on the substrate. The silicate-resistant barrier coating has an engineered microstructure that includes a refractory matrix formed of grains and calcium aluminosilicate additive (CAS additive) dispersed in grain boundaries between the grains.

What is claimed is: 
     
         1 . A gas turbine engine article comprising:
 a substrate; and   a silicate-resistant barrier coating disposed on the substrate, the silicate-resistant barrier coating having an engineered microstructure comprising,
 a refractory matrix formed of grains, and 
 calcium aluminosilicate additive (CAS additive) dispersed in grain boundaries between the grains. 
   
     
     
         2 . The article as recited in  claim 1 , wherein the refractory matrix is selected from zirconia, hafnia, hafnium silicate, zirconium silicate, rare earth silicates, rare earth oxides, mullite, silica, aluminum oxide, or combinations thereof, and the CAS additive includes SiO 2 , AlO 1.5 , and CaO. 
     
     
         3 . The article as recited in  claim 2 , wherein the silicate resistant barrier coating includes, by mol. %, 0.1 to 30 of the CAS additive. 
     
     
         4 . The article as recited in  claim 3 , wherein the silicate resistant barrier coating includes, by mol. %, 3 to 8 of the CAS additive. 
     
     
         5 . The article as recited in  claim 4 , wherein the CAS additive includes, by mol. %, 30 to 90 of SiO 2 , 5 to 20 of AlO 1.5 , and 10 to 50 of CaO. 
     
     
         6 . A plurality of engineered granules, each said engineered granule being an aggregate of: at least one refractory matrix region and at least one calcium aluminosilicate additive region (CAS additive region) attached with the at least one refractory matrix region. 
     
     
         7 . The engineered granules as recited in  claim 6 , wherein each said granule is selected from a mixed granule, a core/shell granule, or combinations thereof, wherein the mixed granule has a plurality of the refractory matrix regions and a plurality of the CAS additive regions attached with the plurality of refractory matrix regions, and the core/shell granule in which the at least one refractory matrix region is a coarse core particle and the at least one CAS additive regions is selected from a plurality of fine shell particles attached on the coarse core particle and a shell coating on the coarse core particle. 
     
     
         8 . The engineered granules as recited in  claim 6 , wherein the at least one refractory matrix region is selected from zirconia, hafnia, hafnium silicate, zirconium silicate, rare earth silicates, rare earth oxides, mullite, silica, aluminum oxide, and combinations thereof, and the at least one CAS additive region includes SiO 2 , AlO 1.5 , and CaO. 
     
     
         9 . The engineered granules as recited in  claim 6 , wherein the at least one CAS additive region is attached with the at least one refractory matrix region by sintering, by electrostatic force, or by a binder. 
     
     
         10 . The engineered granules as recited in  claim 6 , wherein the at least one refractory matrix region has a size of greater than 10 micrometers, and the at least one CAS additive region has a size of less than 5 micrometers. 
     
     
         11 . The engineered granules as recited in  claim 6 , wherein the at least one refractory matrix region has a size of less than 5 micrometers, and the at least one CAS additive region has a size of less than 5 micrometers. 
     
     
         12 . The engineered granules as recited in  claim 6 , wherein each said engineered granule additionally includes at least one auxiliary refractory matrix region attached with the at least one refractory matrix region and the at least one CAS additive region.