Abstract: A gas turbine blade which has previously been in service is protected by cleaning the gas turbine blade, and then first depositing a platinum first layer on the airfoil and the platform of the gas turbine blade. Thereafter, a platinum second layer is deposited over the platform but not the airfoil. A platinum-aluminide protective coating is formed by depositing an aluminum-containing layer overlying both the platform and the airfoil and interdiffusing the platinum and the aluminum.

Abstract: A method for controlled removal of a portion of a diffusion coating from the outer surface of a nickel-containing superalloy article. A diffusion coating typically includes a diffusion layer between an outer aluminide layer and the nickel-containing substrate. The method includes contacting the coated superalloy article in a preselected chemical stripping solution for a preselected period of time sufficient to remove only the outer aluminide layer, without substantially affecting the diffusion layer underlying the outer aluminide layer. After neutralizing the stripping solution, the article can be inspected and repaired as needed. The aluminide outer layer can then be restored in a conventional manner.