Progress in Protective Coatings for Aircraft Gas Turbines: A Review of NASA-Sponsored Research

The status of several recent NASA-sponsored coatings technology programs is reviewed. These programs were focused on problems associated with advanced aircraft gas turbines. In one program, metallic coatings for preventing titanium fires in compressors were identified. The other four efforts were focused on coatings for the turbine section; in one, ductile aluminide coatings for protecting internal turbine-blade cooling passage surfaces were identified. In another, composition-modified external overlay MCrAlY coatings deposited by low-pressure plasma sprayings were found to be more capable of surface protection than vapor-deposited MCrAlY coatings. The remaining two efforts focused on thermal barrier coatings (TBC). In one, computer-aided manufacturing technology was applied to the TBC coating of turbine airfoils. In the other, the design of a turbine airfoil was integrated with a TBC.