Preparation, mechanical and ablation properties of a C/C-TaB2-SiC composite

A C/C-TaB2-SiC composite was successfully prepared by high-solid-loading slurry impregnation combined with polymer infiltration and pyrolysis. The composite had a density of 3.46 g/cm(3) and consisted of pyrolyzed carbon, carbon fibers, TaB2 particles, and precursor-derived SiC with their mass fractions of 7.8 %, 13.0 %, 58.6 %, and 20.6 %, respectively. The C/C-TaB2-SiC composite possessed a flexural strength of 248.2 +/- 16.8 MPa and a fracture toughness of 13.7 +/- 1.6 MPa center dot m(1/2), and demonstrated a non-brittle fracture behavior. After exposure to oxyacetylene flame with a heat flux of 4.18 MW/m(2) for 120 s, the ablation temperature of the sample surface reached a maximum of 2263 degrees C, and the mass and line ablation rates were 2.24 mg/s and 12.92 mu m/s, respectively. The ablation resistance mainly comes from the hindrance of oxygen diffusion by the oxide layer composed of tantalum oxide and a small amount of SiO2.