Microstructure, thermophysical, and ablative performances of a 3D needled C/C-SiC composite

The microstructure, thermophysical, and ablative properties of a 3D needled C/C-SiC composite fabricated by chemical vapor infiltration combined with the liquid silicon infiltration process were investigated. The composite was composed of 64 wt% C, 20 wt% SiC, and 16 wt% Si. The thermal diffusivity in the plane direction was much higher than that in the through-the-thickness direction, while it was reversed for the coefficients of thermal expansion, and the differences reduced with increasing temperature. The linear and mass ablation rates in the oxyacetylene flame were 0.0039 mm/s and 0.0016 g/s on average, respectively. Various ablation processes including sublimation, thermochemical denudation, and oxidations occurred in different sections.