Calcium Magnesium Aluminosilicate (CMAS) Resistant Thermal Barrier Coating and Coating Process Therefor

Abstract

A process for coating a component and a coating system including a bond coat on a superalloy substrate. A thermal barrier material may be applied to the bond coat and a rare earth apatite may be applied to the thermal barrier material via one of Suspension Plasma Spray (SPS) and Solution Precursor Plasma Spray (SPPS) to form an exposed surface. The rare earth apatite may be formed as Ca 2+y RE 8+x (SiO 4 ) 6 O 2+3x/2+y in which −2<y<2 and −2<x<2.

What is claimed: 
     
         1 . A process for coating a component, comprising:
 applying a bond coat on a substrate of an component;   applying a thermal barrier material to said bond coat; and   applying a rare earth apatite to said thermal barrier material.   
     
     
         2 . The process as recited in  claim 1 , further comprising forming said rare earth apatite as a layer with a thickness of about 0.05-20 mil (0.00127-0.508 mm). 
     
     
         3 . The process as recited in  claim 1 , wherein said rare earth apatite is formed as Ca 2+y RE 8+x (SiO 4 ) 6 O 2+3x/2+y  in which −2<y<2 and −2<x<2. 
     
     
         4 . The process as recited in  claim 3 , wherein 0<y<2 and −2<x<0. 
     
     
         5 . The process as recited in  claim 1 , whereas applying said rare earth apatite is formed via one of Suspension Plasma Spray (SPS) and Solution Precursor Plasma Spray (SPPS) to form an exposed surface. 
     
     
         6 . The process as recited in  claim 1 , further comprising applying a layer of rare earth zirconate onto said thermal barrier material prior to application of said rare earth apatite. 
     
     
         7 . The process as recited in  claim 6 , wherein said layer of rare earth zirconate is formed as a layer with a thickness of about 1-20 mil (0.0254-0.508 mm). 
     
     
         8 . The process as recited in  claim 1 , further comprising mixing said rare earth apatite and said rare earth zirconate forming a randomly dispersed system. 
     
     
         9 . The process as recited in  claim 8 , wherein said randomly dispersed system forms a ratio between 80%-20% rare earth apatite. 
     
     
         10 . The process as recited in  claim 8 , wherein said randomly dispersed system forms a ratio between 60%-40% rare earth apatite. 
     
     
         11 . The process as recited in  claim 1 , further comprising, mixing said rare earth apatite and said rare earth zirconate forming a graded layer. 
     
     
         12 . The process as recited in  claim 11 , wherein said graded layer is deposited as 100% rare earth zirconate at said thermal barrier material and gradually transition to 100% rare earth apatite at said exposed surface. 
     
     
         13 . A gas turbine engine component, comprising:
 a superalloy substrate;   a bond coat on said substrate;   a thermal barrier material on said bond coat; and   a rare earth apatite on said thermal barrier material, said rare earth apatite is formed as a Ca 2+y RE 8+x (SiO 4 ) 6 O 2+3x/2+y  in which −2<y<2 and −2<x<2.   
     
     
         14 . The component as recited in  claim 13 , wherein the 0<y<2 and −2<x<0. 
     
     
         15 . The component as recited in  claim 13 , wherein said rare earth apatite is formed as a layer with a thickness of about 0.05-20 mil (0.00127-0.508 mm). 
     
     
         16 . The component as recited in  claim 13 , further comprising a layer of rare earth zirconate between said thermal barrier material and said rare earth apatite. 
     
     
         17 . The component as recited in  claim 15 , wherein said layer of rare earth zirconate is formed as a layer with a thickness of about 1-20 mil (0.0254-0.508 mm). 
     
     
         18 . The component as recited in  claim 13 , further comprising a rare earth zirconate mixed with said rare earth apatite to form a randomly dispersed system. 
     
     
         19 . The component as recited in  claim 13 , further comprising a rare earth zirconate mixed with said rare earth apatite to form a graded layer. 
     
     
         20 . The component as recited in  claim 13 , wherein said rare earth apatite is applied via one of Suspension Plasma Spray (SPS) and Solution Precursor Plasma Spray (SPPS).