材料期刊网

The isothermal oxidation behavior of bulk Ti2AlC in air has been investigated in temperature range 1000-1300degreesC for exposure time up to 20 hr by TGA, XRD, and SEM/EDS. The results demonstrated that Ti2AlC had excellent oxidation resistance. The oxidation of Ti2AlC obeyed a cubic law with cubic rate constants, k(c), increasing from 2.38 x 10(-12) to 2.13 x 10(-10) kg(3)/m(6)/sec as the temperature increased from 1000 to 1300degreesC As revealed by X-ray diffraction (XRD) and SEM/EDS results, scales consisting of a continuous inner alpha-Al2O3 layer and a discontinuous outer TiO2 (rutile) layer formed on the Ti2AlC substrate. A possible mechanism for the selective oxidation of Al to form protective alumina is proposed in comparison with the oxidation of Ti-Al alloys. In addition, the scales had good adhesion to the Ti2AlC substrate during thermal cycling.