Coating method, coating layer, and turbine shroud

Abstract

A coating method includes depositing a slurry including a coarsely particulate ceramic and a finely particulate ceramic on a base material configured with an oxide-based ceramics matrix composite such that a proportion of coarse particles decreases towards a surface of the base material; forming a bond coating by performing a heat treatment on the base material on which the slurry has been deposited; and forming a top coating by thermally spraying a ceramic onto the bond coating. The oxide-based ceramics matrix composite is an alumina silica type oxide-based ceramics matrix composite. The coarsely particulate ceramic and the finely particulate ceramic are alumina-based powder.

1 . A coating film comprising:
 a bond coating obtained by baking a coating material including a coarsely particulate ceramic and a finely particulate ceramic on a base material configured with an oxide-based ceramics matrix composite such that a proportion of coarse particles decreases towards a surface of the base material; and   a top coating formed by thermally spraying a ceramic onto the bond coating,   wherein the oxide-based ceramics matrix composite is an alumina silica type oxide-based ceramics matrix composite, and   the coarsely particulate ceramic and the finely particulate ceramic are alumina-based powder.   
     
     
         2 . The coating film according to  claim 1 , wherein the bond coating includes
 a first bond coating obtained by baking a first coating material in which the coarsely particulate ceramic and the finely particulate ceramic are mixed at a first proportion which has been preset, and   a second bond coating obtained by baking a second coating material in which the coarsely particulate ceramic and the finely particulate ceramic are mixed at a second proportion having a proportion of coarse particles, which is lower than that in the first proportion, on a surface of the first bond coating.   
     
     
         3 . A turbine shroud in which the coating film according to  claim 1  is provided on an inner surface. 
     
     
         4 . A coating film comprising:
 a bond coating obtained by baking a coating material including a coarsely particulate ceramic and a finely particulate ceramic on a base material configured with an oxide-based ceramics matrix composite such that a proportion of coarse particles decreases towards a surface of the base material; and   a top coating formed by thermally spraying a ceramic onto the bond coating,   wherein the oxide-based ceramics matrix composite is a pure alumina type oxide-based ceramics matrix composite, and   the coarsely particulate ceramic and the finely particulate ceramic are alumina-based powder and zirconia-based powder.   
     
     
         5 . The coating film according to  claim 4 , wherein the bond coating includes
 a first bond coating obtained by baking a first coating material in which the coarsely particulate ceramic and the finely particulate ceramic are mixed at a first proportion which has been preset, and   a second bond coating obtained by baking a second coating material in which the coarsely particulate ceramic and the finely particulate ceramic are mixed at a second proportion having a proportion of coarse particles, which is lower than that in the first proportion, on a surface of the first bond coating.   
     
     
         6 . A turbine shroud in which the coating film according  claim 4  is provided on an inner surface. 
     
     
         7 . A coating film comprising:
 a bond coating obtained by baking a coating material including a coarsely particulate ceramic and a finely particulate ceramic on a base material configured with an oxide-based ceramics matrix composite such that a proportion of coarse particles decreases towards a surface of the base material; and   a top coating formed by thermally spraying a ceramic onto the bond coating,   wherein the top coating is a zirconia abradable top coating.   
     
     
         8 . The coating film according to  claim 7 , wherein the bond coating includes
 a first bond coating obtained by baking a first coating material in which the coarsely particulate ceramic and the finely particulate ceramic are mixed at a first proportion which has been preset, and   a second bond coating obtained by baking a second coating material in which the coarsely particulate ceramic and the finely particulate ceramic are mixed at a second proportion having a proportion of coarse particles, which is lower than that in the first proportion, on a surface of the first bond coating.   
     
     
         9 . A turbine shroud in which the coating film according  claim 7  is provided on an inner surface.