Abstract:Al-diffusion/YSZ thermal barrier coatings (TBCs) were deposited on Ti-Al alloys by electronic beam-physical vapor deposition (EB-PVD). The microstructure and phase constituent of the TBCs before and after high temperature oxidation were analyzed by SEM, EDS and XRD. And the high temperature oxidation resistance of the TBCs was measured. The results showed that the top YSZ TBCs were composed of non-equilibrium tetragonal t＇-ZrO2, which had a dense columnar microstructure. The high temperature oxidation resistance of TBCs was much higher than that of the substrate. The oxidation kinetics obeyed logarithmic law. The oxidation rates were 2.2?0-5mg/cm2.h and 1.14?0-3mg/cm2.h at 900℃ and 1000℃, respectively. During the high temperature oxidation, the element diffusion was occurred between the bond layers and the substrates and the interfaces were vanished. Thermal grown oxide (TGO) layers were formed between the surface layers and the bond layers.