Abstract: A method of repairing a damaged area of a thermal barrier coating on a component which is subjected to a hostile thermal environment, which comprises cleaning the damaged area, applying a partially stabilized zirconium sol-gel to the area, and pyrolizing the sol-gel to form a TBC repair layer.

Abstract: Superalloy substrates bearing a rhenium diffusion barrier, and a method of forming a rhenium diffusion barrier between a superalloy substrate and an overlay coating comprising aluminum. The method involves depositing a rhenium film onto the surface of a superalloy substrate and subjecting the rhenium film to first conditions effective to cause a minor portion of rhenium atoms to penetrate the surface of the superalloy substrate and second conditions effective to cause a minority of the rhenium atoms to diffuse into the substrate, forming a diffusion barrier comprising an interfacial zone comprising a mixture of rhenium atoms and atoms of the superalloy substrate covered by a rhenium film. The diffusion barrier is effective to suppress diffusion of aluminum from the overlay coating under static oxidation testing conditions.

Abstract: The present invention provides a method for forming a diffusion barrier at one or more surfaces of a protective coating. In a preferred embodiment, the protective coating is an MCrAlY coating, and the diffusion barrier is a submicron layer of rhenium atoms. The rhenium diffusion barrier is formed by condensing vaporized rhenium onto the surface of the component and substantially simultaneously bombarding the surface with an energetic beam of inert ions. The high, localized concentration of rhenium atoms at the surface(s) of the protective coating dramatically slows the diffusion of constituent elements from the coating.