Thermal barrier coatings and methods of application
A coated part is exposed to a gas flow. The gas flow has a characteristic gas flow direction distribution over a surface of the coated part. The coated part has a substrate having a substrate surface and a coating over the substrate surface. The coating comprises at least one coating layer. A first such layer is columnar and has a column boundary direction distribution. The column boundary direction distribution is selected for partial local alignment with the gas flow direction distribution.
1. A coated part for exposure to a gas flow having a characteristic gas flow direction ( 510 ) distribution over a surface of the coated part, the coated part comprising:
a substrate ( 22 ) having a substrate surface ( 26 );
a coating ( 24 ) over the substrate surface and comprising at least one coating layer, a first said layer ( 52 ) being columnar and having a column boundary direction ( 502 ) distribution, the column boundary direction distribution selected for partial local alignment with the gas flow direction distribution; and
an airfoil portion having a leading edge ( 140 ), a trailing edge ( 142 ), a pressure side ( 144 ) and a suction side ( 146 ),
wherein:
along the respective pressure side and suction side, respective streamwise directions ( 510 ) extend from the leading edge toward the trailing edge; and
a projection ( 502 ′) of the column boundary direction along the surface of the coated part is at an angle (θ 3 ) within 45° of the streamwise direction on majorities of both said pressure side and said suction side.
2. The part of claim 1 wherein:
along at least a portion of the part, the first layer has a thickness of 10-50 micrometer.
3. The part of claim 1 wherein:
along at least a portion of the part, the first layer comprises at least 10% of a local total coating thickness.
4. The part of claim 1 wherein:
along at least a portion of the part, the first layer forms a majority of a local total coating thickness.
5. The part of claim 1 wherein:
the first layer comprises a YSZ.
6. The part of claim 1 wherein:
the first layer is atop a second layer of like composition to the first layer; and
the second layer less aligned with the flow direction distribution than the first layer is aligned with the flow direction distribution.
7. The part of claim 6 wherein:
along at least a portion of the part, a combined thickness of the first layer and second layer is at least 75% of a total coating thickness.
8. The part of claim 1 wherein:
along at least a portion of the part, the first layer is an outermost layer.
9. The part of claim 1 wherein the coating further comprises:
an additional layer atop the first layer and characterized by at least one of:
a remelted microstructure; and
a milled microstructure.
10. The coated part of claim 1 wherein:
along a majority of said surface a second angle (θ 1 ) between the columnar boundary direction and the surface normal is 35-55°.
11. The part of claim 6 wherein the first layer and second layer are ceramic layers.
12. The part of claim 11 wherein the first layer and second layer comprise a YSZ.
13. The part of claim 1 wherein the coating further comprises:
a layer ( 42 ) outboard of said first layer ( 52 ) and having a remelted microstructure.
14. A coated part for exposure to a gas flow having a characteristic gas flow direction ( 510 ) distribution over a surface of the coated part, the coated part comprising:
a substrate ( 22 ) having a substrate surface ( 26 ); and
a coating ( 24 ) over the substrate surface and comprising at least one coating layer, a first said layer ( 52 ) being columnar and having a column boundary direction ( 502 ) distribution, the column boundary direction distribution selected for partial local alignment with the gas flow direction distribution, the part being a combustor panel in an annular combustor of a gas turbine engine and wherein, along a majority of a hot side of the panel, an angle (θ 3 ) between the downstream direction and a projection ( 502 ′) of the column boundary direction is within 30° and the columnar direction distribution is more than 30° off-normal to a surface of said hot side.
15. A method for manufacturing the part of claim 1 comprising:
determining or receiving a part configuration;
determining or receiving the gas flow direction distribution;
from the shape and the gas flow direction distribution, determining an application process associated with the column boundary directions; and
applying the coating to provide the column boundary direction distribution.
16. The method of claim 15 wherein:
the applying of the coating comprises applying the layer via a PVD, EB-PVD, or IE-EB-PVD process.
17. A coated part comprising:
a substrate ( 22 ) having a substrate surface ( 26 ); and
a coating ( 24 ) over the substrate surface and comprising:
a first coating layer ( 52 ) being columnar and having a column boundary direction ( 502 ) distribution, the column boundary direction distribution in partial local alignment with a gas flow direction distribution, wherein:
the surface is a surface of an airfoil or a hot surface of a combustor panel;
a first angle (θ 3 ) between the gas flow direction 510 and a projection ( 502 ′) of the column boundary direction along the surface of the coated part is within 45° along a majority of said surface; and
along a majority of said surface a second angle (θ 1 ) between the columnar boundary direction and a surface normal is 35-55°.
18. The part of claim 17 being a combustor panel in an annular combustor of a gas turbine engine and wherein, along a majority of said hot surface, the second angle is 35-50° and the first angle is less than 20°.
19. The method of claim 15 further comprising:
after applying the coating, milling a surface of the coating to smooth the surface.
20. The method of claim 15 further comprising:
after applying the coating, melting or remelting a surface layer of the coating.