Preparation and oxidation behavior of thermal barrier coatings with a TiAl3 bond coat on γ-TiAl alloy

The thermal barrier coatings investigated in this paper included a TiAl₃ bond coat and an yttria partially stabilized zirconia (YSZ) layer. The TiAl₃ bond coat was prepared by deposition of aluminum by cold spray, followed by a heat-treatment. The YSZ layer was prepared by air plasma spray. The microstructure and composition of the as-sprayed coating were characterized by SEM, EDS and XRD. The oxidation tests of γ-TiAl alloy with and without coating were carried out at 900 ℃ for 504 h in air under quasi-isothermal conditions. The results showed that the thermal barrier coatings decreased the oxidation rate of γ-TiAl alloy effectively. The microstructure and composition of γ-TiAl alloy with and without coating after oxidation were investigated by SEM and EDS. The elements diffusion between the bond coat and γ-TiAl substrate was studied by EPMA.