Impact of TiB ₂ source on the microstructure and properties of TiB ₂ –SiC–B ₄ C ceramics

Abstract

Abstract 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 TiB 2 sources: commercial powder, TiB 2 synthesized by boro/carbothermal reduction, or (Ti,Cr)B 2 synthesized by boro/carbothermal reduction to address the effect of the TiB 2 source. Ceramics containing synthesized TiB 2 or (Ti,Cr)B 2 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)B 2 –SiC–B 4 C ceramic had a thermal conductivity of ∼33 W/m K, an electrical conductivity of ∼10 5 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 TiB 2 –SiC–B 4 C ceramic made with synthesized TiB 2 powder.