Patent ID: 6896488

Claim:
A method for applying a NiAlCrZr diffusion layer and a diffusion aluminide coating to a metal substrate comprising the steps of: providing a superalloy substrate, selected from the group consisting of iron-base superalloys, cobalt-base superalloys, nickel-base superalloys and combinations thereof, and having an internal passage therein defined by an internal surface, and an external surface; providing an alloy comprising nickel, chromium and zirconium; cleaning the external surface and the internal surface of the substrate; coating the external surface of the superalloy substrate with a layer of metal alloy comprising nickel, chromium and zirconium; aluminizing the external surface and the internal surface of the superalloy substrate, whereby a diffusion aluminide layer is formed on the internal surface and whereby the layer comprising nickel, chromium and zirconium becomes a NiAlCrZr diffusion layer; and cooling the substrate to room temperature.