Thermal barrier coating system for superalloy components
AssigneeAlliedSignal Inc.
InventorThomas E. Strangman
Life of this patent
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Abstract
An improvement in a thermal barrier coating for superalloy turbine engine components subjected to high operating temperatures, such as turbine airfoils, e.g., vanes and blades, is disclosed which eliminates the expensive MCrAlY oxidation resistant bond coating underlayer for a columnar grained ceramic thermal barrier coating. In accordance with my present invention, a relatively low cost thermal barrier coating system for superalloy turbine components is provided which utilizes a diffusion aluminide coating layer as the oxidation resistant bonding surface for the columnar grained ceramic insulating coating.
Claims38
A superalloy article of manufacture of the type having a ceramic thermal barrier coating on at least a portion of its surface, comprising:
- (a) a superalloy substrate;
- (b) an adherent, diffusion-aluminide coating applied to said portion of the substrate and adapted to be a reservoir of aluminum for the subsequent in situ formation of an alumina protective scale on said aluminide coated substrate;
- and
- (c) a columnar grained ceramic coating bonded directly to said aluminide coating and adapted to allow in situ oxidation of said aluminide to alumina.
A superalloy article having a ceramic thermal barrier coating, comprising:
- (a) a superalloy substrate;
- (b) an adherent, diffusion-aluminide coating applied to said substrate and forming a reservoir of aluminum for the formation of an alumina protective scale on said aluminide coated substrate;
- (c) a columnar grained ceramic coating bonded to said aluminide-alumina coating;
- and
- (d) wherein the exterior of the ceramic coating is densified by glazing.
The method for producing a superalloy article having an adherent ceramic thermal barrier coating thereon, comprising the steps of:
- (a) providing a superalloy substrate with a clean surface;
- (b) applying a diffusion aluminide layer to at least a portion of the clean superalloy substrate surface;
- and
- (c) applying a columnar grained ceramic coating directly to the diffusion aluminide layer on said superalloy substrate.
The method for manufacturing a superalloy article having an adherent ceramic thermal barrier coating thereon, comprising the steps of:
- (a) providing a superalloy substrate with a clean surface;
- (b) applying a diffusion aluminide layer to at least a portion of the clean superalloy surface;
- (c) applying a columnar grained ceramic coating to the diffusion aluminide layer on said superalloy substrate;
- and
- (d) densifying the exterior of the ceramic coating by electron beam glazing.
The method for manufacturing a superalloy article having an adherent ceramic thermal barrier coating thereon, comprising the steps of:
- (a) providing a superalloy substrate with a clean surface;
- (b) applying a diffusion aluminide layer to at least a portion of the clean superalloy surface;
- (c) applying a columnar grained ceramic coating to the diffusion the clean superalloy surface;
- (d) densifying the exterior of the ceramic coating by laser glazing.
A superalloy article having a thermal barrier coating system thereon, comprising:
- a substrate made of a material selected from the group consisting of a nickel-based superalloy and a cobalt-based superalloy;
- and
- a thermal barrier coating system on the substrate, the thermal barrier coating system including
- an intermetallic bond coat overlying the substrate, the bond coat being selected from the group consisting of a nickel aluminide and a platinum aluminide intermetallic compound,
- a thermally grown aluminum oxide layer overlying the intermetallic bond coat, and
- a columnar grained ceramic topcoat overlying the aluminum oxide layer.
A superalloy article having a thermal barrier coating system thereon, comprising:
- a substrate made of superalloy selected from the group consisting of a nickel-based superalloy and a cobalt-based superalloy;
- and
- a thermal barrier coating system on the substrate, the thermal barrier coating system including
- an aluminide intermetallic bond coat upon the substrate, the bond coat being selected from the group consisting of a nickel aluminide and a platinum aluminide, the bond coat having a thickness of from about 0.001 to about 0.005 inches thick,
- a layer of a thermally grown aluminum oxide upon the intermetallic bond coat, the layer of aluminum oxide being less than about 1 micron thick, and
- a ceramic topcoat upon the layer of aluminum oxide, the ceramic topcoat having a composition of zirconium oxide plus from 0 to about 20 weight percent yttrium oxide and a columnar grain structure wherein the columnar axis is substantially perpendicular to the surface of the intermetallic bond coat.
A process for preparing a superalloy article having a thermal barrier coating system thereon, comprising:
- furnishing a substrate made of a nickel-based superalloy;
- depositing upon the surface of the substrate an aluminide intermetallic coating that has a substantially smooth upper surface, said aluminide intermetallic coating being selected from the group consisting of a nickel aluminide and a platinum aluminide intermetallic compound;
- thermally oxidizing the upper surface of the intermetallic coating to form an aluminum oxide layer;
- and
- depositing upon the surface of the aluminum oxide layer a columnar grained ceramic topcoat by physical vapor deposition.
A thermal barrier coating system for metallic substrates, comprising:
- an intermetallic bond coat overlying a substrate selected from the group consisting of nickel-based, cobalt-based and iron-based superalloys, the bond coat being selected from the group consisting of a nickel aluminide and a platinum aluminide intermetallic compound, and
- a columnar grained ceramic topcoat overlying the intermetallic coating.
A superalloy article having a thermal barrier coating system thereon, comprising:
- a substrate made of a material selected from the group consisting of a nickel-based superalloy and a cobalt-based superalloy;
- and
- a thermal barrier coating system on the substrate, the thermal barrier coating system including
- an intermetallic bond coat overlying the substrate, the bond coat being selected from the group consisting of a nickel aluminide and a platinum aluminide intermetallic compound,
- a thermally grown aluminum oxide layer overlying the intermetallic bond coat, and
- a ceramic topcoat overlying the aluminum oxide layer.
A thermal barrier coating system for metallic substrates, comprising:
- an intermetallic bond coat overlying a substrate selected from the group consisting of nickel-based, cobalt-based and iron-based superalloys, the bond coat being selected from the group consisting of a nickel aluminide and a platinum aluminide intermetallic compound, and
- a ceramic topcoat overlying the intermetallic coating.
Dependencies are inferred from the claim text.