TiB 2 Powders Synthesis by Borothermal Reduction in TiO 2 Under Vacuum

TiB 2 powders were synthesized by borothermal reduction in nanoscale TiO 2 with boron under vacuum. Reaction processes were investigated, and the effect of by‐product B 2 O 3 was evaluated. Results showed that TiO 2 was firstly reduced by boron to form Ti BO 3 and Ti 2 O 3 , and then to produce TiB 2 and B 2 O 3 with increasing temperature. The reaction processes of TiB 2 powders synthesis included two‐step reduction in TiO 2 by boron and the removal of B 2 O 3 . The presence of B 2 O 3 , which was previously reported as the most important factor in promoting the coarsening of ZrB 2 and HfB 2 powders by borothermal reduction, did not lead to significant coarsening of TiB 2 powders. Due to the minor effect of B 2 O 3 , TiB 2 powders with small particle size and low oxygen content could be prepared by direct heat treatment of TiO 2 and boron at 1550°C under vacuum for 1 h. The particle size and oxygen content of synthesized TiB 2 powders were ~0.9 μm and ~1.7 wt%, respectively.