Patent ID: 7413778
Filing Date: 2008-08-19
Classification: C23C,Y10T

Abstract:
1. A method for applying a NiAl based bond coat and a diffusion aluminide coating to a metal substrate comprising: providing a superalloy substrate, the superalloy substrate having an external surface; optionally cleaning the external surface of the superalloy substrate; coating a portion of the external surface of the superalloy substrate, by physical vapor deposition with a layer of a NiAl based metal alloy, wherein the deposited NiAl based metal alloy includes a controlled amount of about 6 to 25 weight percent aluminum to form a coated external portion, wherein the deposited aluminum level of the NiAl based metal alloy is controlled to be about 50-100 weight % of its final level after aluminizing; and subsequently, intentionally and desirably simultaneously aluminizing the coated external portion and a different surface of the superalloy substrate, whereby a diffusion aluminide layer is formed on the different surface and the NiAl based metal alloy becomes a NiAl based bond coat, wherein the NiAl based bond coat comprises between about 12 to 25 weight percent aluminum, wherein the NiAl based bond coat has a uniform distribution of aluminum and other modifying elements selected from the group consisting of Cr, Zr and Hf and mixtures thereof throughout the NiAl based bond coat, and wherein the different surface of the superalloy substrate, which is aluminized, is selected from the group consisting of an external, underportion of a blade platform, an attachment hook of a shroud, and combinations thereof.