Phase Evolution of Ti_3SiC_2 Annealing in Vacuum at Elevated Temperatures

摘要

The thermal decomposition of Ti_3SiC_2 in vacuum furnace up to 1500℃ has been investigated. The results show that the mild decomposition of Ti_3SiC_2 commences at 1300℃ and the higher the holding temperature, the larger the volatilization of Si atoms. The Ti_3SiC_2 decomposition occurs simultaneously on the surface and in the bulk. Four phases coexist at 1400℃ and 1450℃ and the Ti_5Si_3C_x phase appears in the bulk and/or surface. Diffusion distance, rate, and volatilization of Si contribute to the porous structure and the presence of Ti_5Si_3C_x. The evolution of furnace pressure reflects the decomposition kinetics of Ti_3SiC_2.