| 摘要 |
A gas turbine airfoil includes an internal cooling passage defined by an internal airfoil surface, and an external airfoil surface. The gas turbine airfoil is protected on both the internal airfoil surface and the external airfoil surface. The internal airfoil surface is protected by forming a diffusion aluminide protective layer at the internal airfoil surface of the internal cooling passage, with substantially no aluminum deposited on the external airfoil surface during the step of forming. The external airfoil surface is protected by depositing an overlay protective coating on the external airfoil surface, with substantially no aluminum or diffusion aluminide between the overlay protective coating and the external airfoil surface. The gas turbine airfoil is operated in a gas turbine engine, and may later be removed for repair. Repair is accomplished by removing the overlay protective coating from the external airfoil surface of the airfoil, restoring the airfoil dimensions as needed, and depositing a second overlay protective coating on the external airfoil surface of the gas turbine airfoil, with substantially no diffusion aluminide layer between the second overlay protective coating and the external airfoil surface of the airfoil.
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