Ceramic coating composition for compressor casing and methods for forming the same

Abstract

Coating systems for components of a gas turbine engine, such as a compressor casing, are provided. The coating system can include a ceramic material disposed along the compressor casing on a surface to be adjacent to a rotating compressor blade. The coating system is harder than the compressor blade and can reduce the rub ratio between the casing and blade. The coating system can thereby increase the lifetime of the compressor casing and blades. Methods are also provided for applying the coating system onto a compressor casing.

What is claimed is: 
     
         1 . A coated compressor casing, the coated compressor casing comprising:
 a compressor casing defining an inner surface of the compressor casing and comprising a base material, and   a coating system disposed along the inner surface of the compressor casing, wherein the compressor casing is configured to have a compressor blade positioned within the casing, and wherein the coating system comprises a ceramic material that is harder than the compressor blade.   
     
     
         2 . The coated compressor casing according to  claim 1 , wherein the ceramic material comprises yttria stabilized zirconia, mullite, alumina, ceria, rare-earth zirconates, rare-earth oxides, metal-glass composites, zirconia stabilized with an oxide, silicate, chromium oxide, chrome carbide, or combinations thereof. 
     
     
         3 . The coated compressor casing according to  claim 1 , wherein the coating system has a uniform thickness across the inner surface of the compressor casing. 
     
     
         4 . The coated compressor casing according to  claim 1 , wherein the inner surface of the compressor casing is configured to be adjacent to a rotating compressor blade. 
     
     
         5 . The coated compressor casing according to  claim 1 , wherein the coating system has a hardness about 10% to about 50% higher than a hardness of the compressor blade. 
     
     
         6 . The coated compressor casing according to  claim 1 , wherein the coating system has a modulus about 10% to about 50% higher than a modulus of the compressor blade. 
     
     
         7 . The coated compressor casing according to  claim 1 , wherein the coating system has a thickness of about 127 microns to about 254 microns. 
     
     
         8 . The coated compressor casing according to  claim 1 , wherein the coating system includes a bond coat. 
     
     
         9 . The coated compressor casing according to  claim 1 , wherein the coating system is non-abradable. 
     
     
         10 . The coated compressor casing according to  claim 1 , wherein the compressor casing is configured to be positioned in a turbofan engine. 
     
     
         11 . A gas turbine engine comprising:
 a compressor comprising a compressor casing having an inner surface, wherein the compressor casing comprises a base material, and a compressor blade having a blade tip, wherein the compressor blade comprises a base material, and   a coating system disposed along the inner surface of the compressor casing, wherein the coating system has a higher hardness than a hardness of the compressor blade base material.   
     
     
         12 . The system according to  claim 11 , wherein the coating system includes a bond coat. 
     
     
         13 . The system according to  claim 11 , wherein the compressor blade base material is uncoated. 
     
     
         14 . The system according to  claim 11 , wherein the coating system has a hardness about 10% to about 50% higher than a hardness of the compressor blade base material. 
     
     
         15 . The system according to  claim 11 , wherein the compressor blade base material comprises a nickel superalloy. 
     
     
         16 . The system according to  claim 11 , wherein the compressor blade comprises a curved airfoil. 
     
     
         17 . A method of preparing a coated compressor casing, the method comprising:
 forming a coating system comprising a ceramic material along an inner surface of a compressor casing, wherein the compressor casing is configured to have a compressor blade positioned within the casing, and wherein the ceramic material is harder than the compressor blade.   
     
     
         18 . The method according to  claim 16 , wherein forming the coating system along the surface of the compressor casing comprises forming the ceramic material along a surface configured to be adjacent to a rotating compressor blade. 
     
     
         19 . The method according to  claim 16 , wherein forming the coating system along the surface of the compressor casing comprises forming the ceramic material along the surface of the compressor casing to a thickness of about 127 microns to about 254 microns. 
     
     
         20 . The method according to  claim 18 , wherein the coating system has a hardness of about 10% to about 50% higher than a hardness of the rotating compressor blade.