High-temperature oxidation of Ti3AlC2 between 1173 and 1473 K in air

High purity, dense Ti3AlC2 was synthesized via the powder metallurgical route. Oxidation between 1173 and 1473 K in air for up to 100 h resulted in the formation of TiO2 and Al2O3. During the initial stages of oxidation, the dominant reaction was the inward diffusion of oxygen and the outward diffusion of Al. As the scale thickened, Ti diffused outwards to form an outer TiO2 layer, and oxygen was transported inwards to form an inner (TiO2, Al2O3)-mixed layer. At the same time, carbon escaped from Ti3AlC2 into the air. Ti3AlC2 displayed sporadic oxidation behavior, due to the effect of the anisotropy of the matrix grains, the escape of carbon, variations in the sample purity and sample density, and the different sizes of the matrix grains.