Patent ID: 7700154

Claim:
A method for coating a turbine engine component comprising the steps of: providing a coating vessel consisting of a first compartment and a second compartment; placing a turbine engine component having an airfoil portion to be coated within said first compartment; placing means for generating an aluminum containing gas solely in said second compartment, said placing step comprising placing a powder mixture containing a source of aluminum and an activator only in said second compartment; placing said coating vessel within a furnace; introducing a carrier gas into said second compartment via a pipe line passing through a wall of said furnace; heating said powder mixture and said carrier gas to cause an aluminide containing gas to flow into passages in said turbine engine component so as to coat internal surfaces formed by said passages; allowing said aluminide containing gas to flow through said passages and out openings in external surfaces of said turbine engine component; creating a flow of a gas selected from the group consisting of argon, hydrogen, and mixtures thereof over the external surfaces to minimize any build-up of an aluminide coating on said external surfaces while said aluminide containing gas flows out of said openings in said external surfaces, said flow creating step comprising flowing said gas through a pipeline passing through a wall of said furnace and extending through a first wall of said first compartment and flowing said gas into said first compartment at a volume in the range of from 30 to 60 cfh to maintain aluminum coating deposits on said external surfaces resulting from said aluminide containing gas flowing out of said openings in said external surfaces to a thickness less than 0.0005 inches; maintaining said first and second compartments at different pressures so that said gas is forced to flow over said airfoil portion of said turbine engine component; and allowing both said gas and said aluminide containing gas to flow out solely through a single exit.