Powder characteristics,sinterability, and mechanical properties of TiB2 prepared by three reduction methods

Reaction processes, powder characteristics, sinterability, and mechanical properties of TiB₂ prepared by borothermal reduction, B₄C reduction, and boro/carbothermal reduction were compared. Results showed that TiBO₃ and Ti₂O₃ as the intermediate phases existed in the three reduction processes. The temperature where TiB₂ became major phase was lowest during borothermal reduction, resulting in the finest TiB₂ particle size, in contrast to the other two methods, especially boro/carbothermal reduction. However, TiB₂ powders prepared by B₄C reduction and boro/carbothermal reduction after pressureless sintering at 1800°C for 2 hours showed the relatively higher sinterability, due to the lower oxygen content and higher carbon content. Finally, using 5 wt% Ni as sintering additive, hot-pressed TiB₂ ceramics from B₄C reduction demonstrated higher densification, more fine-grained microstructure and higher mechanical properties, due to the better balance of oxygen/carbon content.