Patent ID: 6436473
Filing Date: 2002-08-20
Classification: B32B,C23C,Y10S,Y10T

Abstract:
A process for applying over a nickel-base superalloy substrate a diffusion aluminide coating selected from the group consisting of PtAl and NiAl and combinations thereof having two regions, a first region of aluminide including at least one element selected from the group consisting of Hf, Zr, Y, and Si and combinations thereof, and a second region adjacent to the first region substantially free of elements selected from the group consisting of Hf and Si, comprising the steps of:placing the substrate into an elevated temperature atmosphere having a high concentration of aluminum and at least one element selected from the group consisting of Hf, Zr, Y and Si and combinations thereof for a sufficient period of time for formation adjacent to the substrate of a first region of aluminide coating including at least one element selected from the group consisting of Hf, Zr, Y and Si; and then removing the coated substrate from the elevated temperature atmosphere and placing the coated substrate into an elevated temperature atmosphere having a high concentration of aluminum and substantially free of elements selected from the group consisting of Hf, Zr, Y and Si for a sufficient time to allow for formation over the first region of a second region of aluminide coating substantially free of elements selected from the group consisting of Hf, Zr, Y and Si.