Abstract: A method for removing an environmental coating on an article intended for use in a hostile environment, such as turbine, combustor and augmentor components of a gas turbine engine. The method is particularly suited for the repair of diffusion aluminide coatings covered by a protective oxide scale, which may further include a thermal insulating ceramic outer layer. Processing steps generally include peening the environmental coating at a temperature below the ductile-to-brittle transition temperature of the diffusion coating, such that cracks are formed in the diffusion coating. Thereafter, the diffusion coating is subjected to an acidic solution that penetrates the cracks and interacts with the coating diffusion zone, resulting in the diffusion coating being chemically stripped from its underlying substrate.

Abstract: A gas turbine engine turbine airfoil includes first and second opposite sidewalls joined together at leading and trailing edges and extending from a root to a tip thereof. The sidewalls have respective outer surfaces over which is flowable combustion gases during operation. The sidewalls are spaced apart to define an internal flow passage for receiving a cooling fluid. A plurality of ejection slots are arranged in a column through the first sidewall and have flow inlets for receiving cooling fluid from the internal flow passage and ejecting the fluid from respective flow outlets along the outer surface. At least some of the ejection slots are inclined at an acute ejection angle which varies in magnitude for preferably matching the respective inclination of combustion gas streamlines flowable over the airfoil surface.