Effects of Powder Purity and SPS Conditions on Microstructure and Mechanical Properties of Monolithic TiB2 Ceramics

TiB2 ceramics have a wide range of applications due to their exceptional properties. However, high relative density must be achieved to enable their use in cutting tools, wear-resistant components, body armor, and extreme environment applications. In this study, high-purity TiB2 powders with hexagonal platelet-like morphology were synthesized through boro/carbothermal reduction reactions under Ar flow. In-house synthesized and commercial TiB2 powders were consolidated via spark plasma sintering. The effects of oxygen content, sintering temperature, and hold time on the microstructure, elastic and mechanical properties of monolithic TiB2 ceramics were investigated. The highest relative density of 99.43%, elastic modulus of 541 GPa, and Vickers microhardness of 40.35 GPa were achieved at 1750 °C for a hold time of 45 min. The exceptional properties, among the highest achieved for spark plasma sintered monolithic TiB2, are attributable to preferential kinetic conditions and the powder’s morphology.