Enhanced mechanical/electrical properties of in situ synthesized SiC-TiB2 ceramic composites by reactive hot-pressing sintering

In this work, in situ formed TiB 2 -reinforced SiC ceramic composites were prepared by reactive hot pressing using SiC, TiC, B 4 C, and Si as raw materials. Phase composition, microstructure, and mechanical as well as electrical properties were investigated. The formation of the TiB 2 phase could be realized from the reaction among TiC, B 4 C, and Si. In the sintered SiC–TiB 2 ceramic composites, the content of α-SiC decreased while that of the in situ formed TiB 2 increased. In addition, residual Si only existed in the SiC–TiB 2 ceramic composites with in situ TiB 2 below 20 mol%. Notably, the comprehensive performance of the SiC–TiB 2 ceramic composites was enhanced with the increase of TiB 2 content due to the reduction of pores and residual Si. Finally, nearly fully dense SiC–TiB 2 ceramic composites were obtained when in situ formed TiB 2 was above 20 mol%. The SiC–TiB 2 ceramic composites, with in situ TiB 2 of 30 mol%, exhibited hardness of 26.9 ± 2.3 GPa, fracture toughness of 6.83 ± 0.6 MPa m 1/2 , and electrical resistivity of 0.3 mΩ cm, respectively.