Coating method, coating layer, and turbine shroud

A coating method comprising:

• 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 slurry,
• 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,
• wherein the oxide-based ceramics matrix composite is a pure alumina type oxide-based ceramics matrix composite, and
• the coarsely particulate ceramic is a mixture of alumina-based powder and zirconia-based powder and the finely particulate ceramic is a mixture of alumina-based powder and zirconia-based powder,
• wherein the depositing includes
• depositing a first slurry in which the coarsely particulate ceramic and the finely particulate ceramic are mixed at a first proportion which has been preset, on the base material, and
• depositing a second slurry 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 slurry.

A coating method comprising:

• 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 slurry,
• 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,
• wherein the top coating is a zirconia abradable top coating, and
• wherein the depositing includes
• depositing a first slurry in which the coarsely particulate ceramic and the finely particulate ceramic are mixed at a first proportion which has been preset, on the base material, and
• depositing a second slurry 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 slurry.