Impact of TiB2 source on the microstructure and properties of TiB2–SiC–B4C ceramics

To date, the thermal and electrical properties of three-phase ceramics containing a boride phase, silicon carbide, and boron carbide have not been studied in detail. Further, the effect of the source of the boride powder has also not been investigated. This study produced three-phase ceramics containing titanium diboride, silicon carbide, and boron carbide using three different TiB2 sources: commercial powder, TiB2 synthesized by boro/carbothermal reduction, or (Ti,Cr)B2 synthesized by boro/carbothermal reduction to address the effect of the TiB2 source. Ceramics containing synthesized TiB2 or (Ti,Cr)B2 reached >99% relative density, while the ceramic produced from commercial powder reached ∼93% relative density. The addition of Cr reduced both the thermal and electrical conductivities, but had little effect on the Vickers hardness. The (Ti,Cr)B2–SiC–B4C ceramic had a thermal conductivity of ∼33 W/m K, an electrical conductivity of ∼105 S/m, and a hardness of ∼61 GPa at 0.49 N. The highest hardness of ∼66 GPa at a load of 0.49 N was for the TiB2–SiC–B4C ceramic made with synthesized TiB2 powder.