High temperature oxidation properties of laser clad composite coatings on TiAl intermetallic alloy

γ-NiCrAl/Cr₇C₃/TiC composite coatings were fabricated on γ-TiAl intermetallic alloy by laser cladding with NiCr-Cr₃C₂ precursor mixed powders. The elevated-temperature isothermal oxidation-resistance was conducted in a high-temperature electric resistance furnace at 1000°C for 50 h in air. The corresponding oxidation mechanisms were also discussed based on the experimental results. The results show that the isothermal elevated-temperature (1000°C) oxidation resistance of the laser clad composite coatings is enhanced significantly and the relatively continuous oxide scales consist of Al₂O₃, Cr₂O₃ and TiO₂. While the original TiAl alloy has poor elevated-temperature oxidation resistance and the oxide scales are brittle and porous and are mainly composed of TiO₂ in the top layer oxide scale and TiO₂+α-Al₂O₃ near the scale/substrate.