Phase Evolution of Ti3SiC2 Annealing in Vacuum at Elevated Temperatures

The thermal decomposition of Ti3SiC2 in vacuum furnace up to 1500 degrees C has been investigated. The results show that the mild decomposition of Ti3SiC2 commences at 1300 degrees C and the higher the holding temperature, the larger the volatilization of Si atoms. The Ti3SiC2 decomposition occurs simultaneously on the surface and in the bulk. Four phases coexist at 1400 degrees C and 1450 degrees C and the Ti5Si3Cx phase appears in the bulk and/or surface. Diffusion distance, rate, and volatilization of Si contribute to the porous structure and the presence of Ti5Si3Cx. The evolution of furnace pressure reflects the decomposition kinetics of Ti3SiC2.