Oxidation behavior of Ti3AlC2 powders in flowing air

The oxidation behavior of Ti3AlC2 powders has been investigated in air by means of simultaneous TGA-DSC, XRD, Raman spectra, SEM, EDS and BET specific surface measurement to understand the intrinsic oxidation behavior of this newly developed ternary compound. The starting and complete oxidation temperatures determined by simultaneous TGA-DSC were 400 and 1120 degreesC, respectively. These temperatures are higher than those for TiC, suggesting that Ti3AlC2 is more oxidation resistant than TiC. An anomalous oxidation temperature range of 550-650 degreesC in which the final mass gains due to the isothermal oxidation of Ti3AlC2 powders at 550, 600 and 650 degreesC for 2 h are significantly greater than that at a higher temperature of 700 degreesC, was observed. This anomalous oxidation behavior suggests that direct reaction dominated with high oxidation kinetics in this temperature range, which was confirmed by SEM morphology observation and BET specific surface area measurement. The oxidation of Ti3AlC2 powders at temperatures below 700 degreesC resulted in two modifications of TiO2 (anatase and rutile). At temperatures above 800 degreesC the oxidation products consisted of rutile TiO2 and alpha-Al2O3.