Patent ID: 6139649
Filing Date: 2000-10-31
Classification: C10G,C23C

Abstract:
A method of coating a surface of a metal product formed from a nickel chromium alloy comprising:a. exposing the surface to hydrogen at elevated temperatures to remove diffusion limiting oxides and form a prepared surface;b. diffusing a sufficient amount of at least one metal selected from the group consisting of chromium, silicon, aluminum, magnesium, zirconium, manganese and titanium onto the prepared surface to form a coating having a thickness of at least 50 microns;c. heating a surface of the coating to a sufficient temperature to form a spinel at the surface of the coating; andd. treating the surface of the coating which has been heated with at least one gas selected from the group consisting of argon, nitrogen, helium and oxygen at a sufficiently high temperature to form stable oxides.