Ablation mechanisms of Ti3SiC2 ceramic at 1600 °C in nitrogen plasma flame

Abstract

Present work showed that Ti3SiC2 ceramic has good ablation resistance at 1600 °C. The mass ablation rate and linear ablation rate after exposure to plasma flame for 120 s are −0.23 mg/s and 5.58 μm/s, respectively. After ablation for 120 s, the micro-morphologies of cross section of the ablation fringe show that the ablation layer was divided into four-layers: an oxide outer layer, a porous layer, a decomposition layer, and the matrix layer. The formation of porous layer is mainly related to the Ti vacancies caused by the outward diffusion of Ti ions, and outward diffusion of gaseous SiO and CO. The dense and large grain-sized TiO2 oxide layer is dismembered by the generated SiO2 to form a fine-structured TiO2 and SiO2 mixture. The solid-liquid mixed oxide layer is quickly blown away under the shearing force of plasma flow, resulting in a significant increase of linear ablation rate.