Thermal stability of Ti3AlC2 in Ar-10vol.%CO atmosphere

Abstract

Thermal stability of Ti3AlC2 at 1250–1400°C in 10%CO-Ar atmosphere has been investigated. Decomposition of Ti3AlC2 occurs when the temperature is 1250°C. After the treatment at 1300–1400°C, nanoscale aluminum oxycarbides (Al2OC and Al4O4C) were formed on the sample surface due to the reaction between Al and CO. At 1250–1300°C, a mixture layer of Ti(O,C) and Al2O3 was formed; while at 1350–1400°C, the reaction scale below the nanoscale aluminum oxycarbides are a duplex layer with a porous Ti(O,C) inner layer and a mixture of Ti(O,C) and Al-containing compounds outer layer. The outward extraction of Al and Ti along some special planes, i.e., {0001} and {11−20} of Ti3AlC2, is believed to result in the orderly arranged pores in the inner porous Ti(O,C) layer.