Oxidation behavior of Ti3SiC2 at high temperature in air

The oxidation behavior of ternary compound Ti3SiC2 is investigated in the temperature range of 1000-1500 degreesC for up to 20 h exposure. The scales formed on the Ti3SiC2 matrix were duplex, consisting of an outer layer and an inner layer over the temperature ranges. The outer layer was pure TiO2 (rutile), and the inner layer consisted of SiO2 and TiO2. At the temperature 1300 degreesC and below, the oxidation kinetics of Ti3SiC2 followed the parabolic law. When the temperature rose to 1400 degreesC, the oxidation behavior followed the parabolic-linear law. The activation energy was calculated to be 325 kJ mol(-1) over the temperature range of 1000-1400 degreesC. A number of pores existing in the boundary of the outer layer and the inner layer provide the cannel for oxygen diffusion. The effect of pores and impurities on oxidation behavior was analyzed, and the morphology of oxidation products was observed through scanning electron microscope. (C) 2002 Elsevier Science B.V. All rights reserved.