Methods of forming a protective diffusion layer on nickel, cobalt, and iron base alloys
AssigneeTurbine Components Corporation
InventorsSrinivasan Shankar, G. William Goward
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Abstract
Methods are provided for forming protective diffusion layers on nickel, cobalt and iron base alloy parts comprising the formation of a diffusion layer of platinum, chromium and aluminum on said surfaces either by deposition of platinum and gas phase chromizing followed by aluminizing or by gas phase chromizing and deposition of platinum followed by aluminizing, or by gas phase chromizing followed by aluminizing and deposition of platinum, said gas phase chromizing performed out of contact with a source of gaseous chromizing species at elevated temperature, said aluminizing performed either out of contact or in contact with a powder mixture at elevated temperature.
Claims29
A method for forming a protective diffusion layer of chromium, platinum group metal and aluminum on nickel, cobalt and iron base alloy parts comprising the steps of depositing a coating of a platinum group metal on the surface of the part to be protected, forming a diffusion layer of platinum group metal and chromium on said surfaces by gas phase chromizing said surfaces out of contact with a source of gaseous chromizing species at elevated temperature, and forming a diffusion layer of platinum group metal, chromium and aluminum on said surfaces by aluminizing said surfaces at elevated temperature.
A method as claimed in claim 13 wherein the part is heated to a temperature between about 1500.degree. F. and 2000.degree. F. in one of a vacuum or inert atmosphere for one to five hours.
Dependencies are inferred from the claim text.