METHOD FOR REFURBISHING PTAL COATING TO TURBINE HARDWARE REMOVED FROM SERVICE

摘要

A method of repairing airfoils damaged during operation and removed from service. The method comprises the steps of stripping any thermal barrier coatings from the airfoil. After the thermal barrier coatings are removed, cracks are removed from the airfoil. Cracks usually appear in the bond coat area over the fillet portion of the airfoil, which are removed by locally grit blasting the fillet portion of the airfoil. This operation also usually results in locally removing the bond coating from the fillet portion. Cracks and other foreign-object induced damage may be sustained by the airfoil tip, which is removed and replaced by welding superalloy material. The airfoil then may be cleaned by thermal etching. The airfoil is then placed in a plating tool that permits preferential plating of areas of the airfoil from which plating has been removed. After plating, the airfoil is then diffusion heat treated to diffuse the platinum coating with the superalloy substrate materials. The diffusion heat treated airfoil is then aluminided by any aluminiding process to form a PtAl coating.