Towards a better understanding of the high-temperature oxidation of MAX phase Cr2AlC

High-temperature oxidation of bulk single crystal, fine and coarse grained polycrystals Cr2AlC has been performed from 800 °C to 1500 °C. In the temperature range T = [800;1400] °C, an ?-Al2O3 scale with a Cr7C3 subscale are in-situ formed independently initial microstructure on top Cr2AlC. CALPHAD calculations were explain formation instead expected mixture carbides, indicating favourable driving force for formation. The kinetic study is consistent previous works activation energy about 400 kJ.mol?1. Oxidizing longer time (1000 h) or at higher (1500 °C) leads chromia in former alumina scale, which correspond calculated equilibrium phases.