Cyclic Oxidation of Ternary Layered Ti2AlC at 600–1000°C in Air

The cyclic oxidation of bulk Ti2AlC at intermediate temperatures of 600–1000°C in air was studied by thermogravimetric analysis. It was demonstrated that Ti2AlC exhibited good cyclic-oxidation resistance at temperatures above 700°C. The cyclic-oxidation kinetics approximately follows a parabolic rate law at 700–1000°C range. The surface scales are dense, resistant to spalling and adhesive to Ti2AlC substrate. An abnormal oxidation whose cyclic-oxidation kinetics obeys a linear law is observed at 600°C. As revealed by scanning electron microscope (SEM), oxidation-induced cracks present at 600°C results in poor protectivity and accounts for the abnormal oxidation. The cracks are caused by the stress associated with the volume expansion due the formation of anatase TiO2 in the scale.