Oxidation behavior of Ti3AlC2 at 1000-1400°C in air

The isothermal oxidation behavior of bulk Ti3AlC2 has been investigated at 1000-1400 degreesC in air for exposure times up to 20 h by means of TGA, XRD, SEM and EDS. It has been demonstrated that Ti3AlC2 has excellent oxidation resistance. The oxidation of Ti3AlC2 generally followed a parabolic rate law with parabolic rate constants, k(p) that increased from 4.1 x 10(-11) to 1.7 x 10(-8) kg(2) m(-4) s(-1) as the temperature increased from 1000 to 1400 degreesC. The scales formed at temperatures below 1300 degreesC were dense, adherent, resistant to cyclic oxidation and layered. The inner layer of these scales formed at temperatures below 1300 degreesC was continuous alpha-Al2O3. The outer layer changed from rutile TiO2 at temperatures below 1200 degreesC to a mixture of Al2TiO5 and TiO2 at 1300 degreesC. In the samples oxidized at 1400 degreesC, the scale consisted of a mixture of Al2TiO5 and, predominantly, alpha-Al2O3, while the adhesion of the scales to the substrates was less than that at the lower temperatures. Effect of carbon monoxide at scale/substrate was involved in the formation of the continuous Al2O3 layers. (C) 2002 Elsevier Science Ltd. All rights reserved.