Method for depositing gamma-prime nickel aluminide coatings

摘要

Methods for depositing an overlay coating (24) on articles (10) intended for use in hostile thermal environments. The coating (24) has a predominantly gamma prime-phase nickel aluminide (Ni 3 Al) composition suitable for use as an environmental coating and as a bond coat of a thermal barrier coating system (20). The coating (24) further contains at least one platinum group metal, preferably chromium, optionally one or more reactive elements, and optionally silicon. The coating (24) is deposited by a process that entails forming a platinum group metal layer and at least one separate layer of other constituents of the coating (24), and then performing a diffusion heat treatment to yield the coating (24).