Patent ID: 6929825

Claim:
A method for applying an aluminide coating on a gas turbine engine blade having an external surface and an internal cooling cavity defined by an internal surface that is connected to the external surface by cooling holes, the method being conducted in a vapor coating container having a hollow interior coating chamber, the method comprising the steps of: (a) loading the coating chamber with the blade to be coated; (b) providing an aluminide coating gas in the loaded coating chamber; (c) flowing an inert carrier gas into the loaded coating chamber comprising the aluminide coating gas at a gas flow rate of from about 60 to about 150 ft. 3 /hour (from about 1699 to about 4248 liters/hour) for from about 2 to about 6 hours to move the aluminide coating gas through the cooling holes and internal cooling cavity of the blade, while maintaining the loaded coating chamber at a temperature of from about 815 to about 980° C., to deposit an aluminide coating on the internal surface of the blade; and then (d) flowing an inert carrier gas into the loaded coating chamber comprising the aluminide coating gas at a gas flow rate of from 0 to about 150 ft. 3 /hour (from 0 to about 4248 liters/hour) for from about 2 to about 6 hours, while maintaining the loaded coating chamber at a temperature of from about 1040 to about 1125° C., to deposit an aluminide coating on the external surface of the blade.