ABSTRACT
Gamma titanium aluminide-based alloys are considered to be suitable as structural materials for high-temperature applications due to their attractive properties, including low density, high specific stiffness and tensile strength, and good creep resistance. The development of oxidation-resistant coatings with long-term protection capability is still a major issue for high-temperature structural applications of gamma titanium aluminides. Thermal barrier coatings (TBCs) are widely used in aeroengines and land-based gas turbines. Through the use of TBCs and internal cooling, the components can operate at substantially lower temperatures than the surface temperature of the ceramic coating. The presence of zirconia particles within the oxide, serving as markers to determine the diffusion direction, indicated that this outer oxide scale grew by the outward diffusion of titanium and aluminium cations to the TBC/oxide interface where they formed titania and alumina.
