Patent ID: 7524382

Claim:
A method for preparing a coated article, comprising the steps of: providing a nickel-based superalloy substrate, the nickel-based superalloy substrate including at least one refractory element; cleaning a surface of the nickel-based superalloy substrate by removing surface oxides; placing the substrate article in a working zone of a furnace; heating the substrate article to a carburizing temperature while maintaining a non-oxidizing atmosphere in the working zone of the furnace; upon reaching the carburizing temperature, introducing into the working zone of the furnace a carburizing gas selected from the group consisting of alkynes, ethylene, propane and combinations thereof; maintaining sufficient carburizing gas in the working zone of the furnace for a time and at a temperature to carburize a near surface region of the superalloy substrate to a maximum depth of about 100 microns; then, stopping the flow of carburizing gas into the working zone of the furnace and substantially simultaneously introducing a non-reactive gas into the working zone of the furnace to cool the article to a preselected carburizing temperature; and thereafter applying an aluminide coating to at least a portion of the surface cleaned by removing surface oxides.