Improvement of high-temperature oxidation resistance of TiAl-based alloy by sol–gel method

Sol–gel spin-coating of SiO2 was applied on a TiAl-based alloy, and subsequent heat treatment was performed at 1000 °C by embedding in active carbon. It was revealed by XRD and SEM/EDS analysis that a composite coating constituted of sublayers of SiO2, Al2O3 and TixSiy in succession from the outer to inner formed on TiAl-based alloy after the treatment. Cyclic oxidation test showed that the sol–gel coating combined with the subsequent heat treatment is effective in improving the oxidation resistance of TiAl alloys.