Method for applying aluminide coatings to superalloys
AssigneeUnited Technologies Corporation
InventorsWalter E. Olson, Michael S. Milaniak, Clark T. Okawa
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Abstract
A powder mixture for applying gas phase aluminide coatings to nickel or cobalt base superalloys is described. A preferred mixture consists essentially of Co.sub.2 Al.sub.5, NH.sub.4 F.HF, and chromium metal. The mixture is substantially free of aluminum oxide.
Claims9
A method for forming an aluminide coating on the surface of a substrate selected from the group consisting of nickel and cobalt base alloys, the method comprising the step of heating the substrate in the presence of a powder mixture consisting essentially of, by weight percent, 5-20 NH.sub.4 F.HF, 10-30 Cr, up to 10 Al.sub.2 O.sub.3, balance Co.sub.2 Al.sub.5.
A method for forming a gas phase aluminide coating on a nickel or cobalt base superalloy article, comprising the step of heating the article and a powder mixture consisting essentially of cobalt aluminum, ammonium bifluoride and an effective amount of chromium metal to form an outward diffusing aluminide coating, the powder mixture being substantially oxide free.
A method for forming a gas phase aluminide coating on a nickel or cobalt base superalloy article, comprising the steps of disposing the article in out-of-contact relation with a powder mixture which consists essentially of about, by weight percent, 5-20 NH.sub.4 F.HF, 10-30 Cr, up to 10 Al.sub.2 O.sub.3, balance Co.sub.2 Al.sub.5, and heating the powder mixture to cause diffusion of aluminum into the article surface.
Dependencies are inferred from the claim text.