Preparation and Characterization of Reaction Sintering B<sub>4</sub>C/SiC Composite Ceramic

High hardness, high strength, high fracture toughness and low density are required for novel bulletproof materials. B 4 C/SiC composite ceramic is one of the most potential candidates. In this study, B 4 C/SiC composite ceramic was prepared by reaction sintering. The influence of B 4 C content, species and content of carbon, sintering temperature on the mechanical properties of B 4 C/SiC composite ceramic were studied. A high performance B 4 C/SiC composite ceramic was sintered at 1750°C for 30 min. Phenolic resin and carbon black were both chosen as carbon sources, whose favorable contents were 10wt%, 5wt%, respectively. The density of sintered bodies reduces with B 4 C content increases. To some extent, fracture toughness, bending strength improve initially and then deteriorate with the increase of B 4 C content whose optimal amount is 30wt%. The optimal fracture toughness and bending strength of the B 4 C/SiC composite ceramic are 5.07MPa·m 1/2 and 487MPa, respectively. Meanwhile, the Viker-hardness of the sintered body is 30.2GPa, the density is as low as 2.82g/cm 3 .