Patent ID: 6334907
Filing Date: 2002-01-01
Classification: C23C

Abstract:
A process for forming a diffusion aluminide coating, the process comprising the steps of:placing a substrate in a coating chamber; providing within the coating chamber an aluminum-containing vapor having a substantially constant aluminum activity; flowing an inert or reducing gas into and through the coating chamber; and producing a diffusion aluminide coating on the substrate by contacting the substrate with the aluminum-containing vapor to cause a portion of the aluminum-containing vapor to react with and deposit aluminum on the substrate while maintaining the substantially constant aluminum activity of the aluminum-containing vapor within the coating chamber, and while controlling the rate at which aluminum is deposited on the substrate by altering the flow rate of the gas through the coating chamber so that a portion of the unreacted aluminum-containing vapor is swept from the coating chamber by the gas, and so that greater amounts of the unreacted aluminum-containing vapor are swept from the coating chamber with higher gas flow rates.