Cyclic oxidation of Ti3AlC2 at 1000–1300 °C in air

The cyclic-oxidation behavior of Ti3AlC2 was investigated at 1000–1300 °C in air for up 40 cycles. It was revealed that Ti3AlC2 had excellent resistance to thermal cycling. The cyclic oxidation of Ti3AlC2 basically obeyed a parabolic law. In all cases, the scales were dense, resistant to spalling and highly stratified. The inner continuous α-Al2O3 layer was well adhesive, while the outermost layer changed from rutile TiO2 at temperatures below 1100 °C to Al2TiO5 at 1200 and 1300 °C, respectively. At 1300 °C, a mechanical-keying structure of inner Al2O3 to the Ti3AlC2 substrate formed, which improved the resistance to scale-spallation.

Research highlights
► In this manuscript, the cyclic-oxidation behavior of Ti3AlC2 was systematically studied at 1000–1300 °C in air for up 40 cycles for the first time.
► The results revealed that Ti3AlC2 had excellent resistance to thermal cycling. The cyclic oxidation of Ti3AlC2 mostly obeyed a parabolic law from 1000 to 1300 °C. In all cases, the scales were dense, crack-free, resistance to spalling and highly demixed. The inner continuous α-Al2O3 layer was well adhesive to Ti3AlC2. The outermost layer was changed from rutile TiO2 at temperatures below 1100 °C to Al2TiO5 at 1200 and 1300 °C, respectively.
► At 1300 °C, a mechanical-keying structure of inner Al2O3 to the Ti3AlC2 substrate, which improved the resistance to scale-spalling, was discovered for MAX phase materials for the first time.