Boron carbide (B₄C) ceramics were synthesized by spark plasma sintering at a temperature between 1600 and 2050 °C without employing any sintering additives. The effect of sintering process parameters, such as temperature, holding time, pressure, hearting rate, and pulsed electric current, and the particle size of the raw powder on the densification behavior and mechanical properties of B₄C ceramics, were comprehensively and systematically investigated. Hardness and fracture toughness of B₄C that has a density close to the theoretical value were found to be 33.5 ± 0.2 GPa and 3.21 ± 0.13 MPa·m^1/2, respectively. Electron backscatter diffraction (EBSD) analysis revealed no abnormal growth of grains due to an increase in holding time and pressure. Twin structures present in ceramics are beneficial for their mechanical performance.

Silicon carbide (SiC) ceramics with Y₂O₃-Er₂O₃ as sintering additives were prepared by spark plasma sintering (SPS). The effects of sintering temperatures and Y₂O₃-Er₂O₃ contents on the microstructure, thermal conductivity, electrical, and mechanical properties were investigated. The increasing of sintering temperatures promoted the densification of SiC ceramics, thus increasing the thermal conductivity and electrical resistivity. With the increase of the sintering additive contents, the electrical resistivity increased due to the formation of the electrical insulating network; and the thermal conductivity first increased and then decreased, which was related to the content and distribution of the secondary phase among the SiC grains. The SiC ceramics sintered at 2000 °C with 9 wt.% Y₂O₃-Er₂O₃ exhibited higher electrical resistivity and thermal conductivity, which were 4.28 × 10⁹ Ω·cm and 96.68 W/m·K, respectively.