Substrate stabilization of diffusion aluminide coated nickel-based superalloys
AssigneeGeneral Electric Company
InventorJon C. Schaeffer
Life of this patent
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Abstract
A superalloy article has a nickel-based superalloy substrate containing TCP-phase forming elements such as rhenium, chromium, tantalum and tungsten. A carbide precipitate-containing region is formed within the substrate extending to a carbide depth below a surface of the substrate, preferably by depositing carbon on the surface of the substrate and diffusing the carbon into the substrate. An aluminum-rich diffusion layer extends from the surface of the substrate to an aluminide depth below the surface of the substrate. Preferably, the carbide depth is about the same as the aluminide depth. The presence of the carbide precipitates inhibits the formation of the deleterious TCP-phase.
Claims18
A superalloy article, comprising:
- a nickel-based superalloy substrate containing TCP-phase forming elements;
- a carbide precipitate-containing region within the substrate and extending to a carbide depth below a surface of the substrate;
- and
- an aluminum-rich diffusion layer extending from the surface of the substrate to an aluminide depth below the surface of the substrate.
A superalloy article, comprising:
- a nickel-based superalloy substrate containing refractory elements selected from the group consisting of rhenium, chromium, tantalum, tungsten and combinations thereof;
- a carbide precipitate-containing region within the substrate and adjacent to a surface of the substrate, and
- a layer of aluminum coated over at least a portion of the surface of the substrate.
A superalloy article, comprising:
- a nickel-based superalloy substrate susceptible to the formation of a secondary reaction zone during aluminiding treatments, the substrate being depleted of TCP-phase forming elements to a depleted depth below a surface of the substrate;
- and
- an aluminum-rich diffusion layer extending from the surface of the substrate to an aluminide depth below the surface of the substrate, the depleted depth being at least as great as the aluminide depth.
A process for preparing a coated article, comprising the steps of:
- furnishing a nickel-based superalloy substrate containing rhenium, chromium, tantalum and tungsten;
- depositing a carbon-containing layer over a surface of the substrate;
- diffusing carbon from the carbon-containing layer into the substrate at a temperature sufficient to form carbide precipitates in the substrate;
- depositing an aluminide coating on the surface of the substrate;
- and
- heating the substrate to form a protective layer containing aluminum and nickel at the surface of the substrate.
Dependencies are inferred from the claim text.