An environmentally friendly route to prepare hierarchical carbon/carbon–SiC composites by carbothermal reduction

Hierarchical carbon/carbon–SiC composites have been prepared by a carbothermal reduction process using impregnated silica as a precursor and 3D needle-punched C/C composites as templates at 1450 °C. Dense SiC layers surrounding the pyrocarbon were synthesized by further heat-treatments at 1600 °C. The resulting composites are composed of turbostratic carbon, β-SiC and 4H type α-SiC, and show pseudo-plastic fracture behavior and excellent toughness. The flexural strength of parallel and perpendicular direction to carbon fiber clothes of the composites are about 155 and 100 MPa. The preparation of these composites releases very small amounts of corrosive gases and the materials obtained are easily machined.