Structures and properties of ceramic films on TiAl intermetallic compound fabricated by microarc oxidation

The ceramic oxide films with a thickness of 120 μm were prepared on γ-TiAl intermetallic compound by alternating-current microarc oxidation in silicate electrolyte. Isothermal oxidation of TiAl alloy coated with the ceramic oxide film was carried out in air at 1100 °C. Result showed that the dense layers in the oxide film were mainly composed of Al2TiO5 and TiO2 rutile phase, while the loose layer contained a large amount of amorphous SiO2 besides Al2TiO5 and TiO2 rutile phase. Thermal shock tests revealed a good adhesion between the films and TiAl substrate, and the oxidation resistance of the TiAl alloy was improved.