Synthesis and performance of TiB ₂ –B ₄ C composites by high pressure of TiC–B mixture

Abstract TiB ₂ –B ₄ C composites were in situ synthesized and consolidated by high pressure synthesis method from a mixture of TiC and B powders at the pressure and temperature of 5.0 GPa and 1500℃‐1900℃. The phase composition, microstructure, density, hardness, thermal conductivity, and electrical resistivity of TiB ₂ –B ₄ C composites were analyzed. As the increase in the synthesis temperature, the products were TiB ₂ and B ₄ C phases and that crystallinity improved. TiB ₂ –B ₄ C composites were dense without obvious pores. TiB ₂ –B ₄ C composites synthesized at 1800℃ obtained the optimized performance, including the relative density of 98.2%, the Vickers hardness of 31.7 ± 1.2 GPa with the load of 9.8 N, the thermal conductivity of 30.3 ± 0.7 W/(m K), and the electrical resistivity of 3.3 × 10 ⁻³ Ω cm, respectively. The grain size of the TiB ₂ –B ₄ C composites changed with the increase in synthesis temperature, leading to the changes in hardness, thermal conductivity, and electrical resistivity.