TiB2 Powders Synthesis by Borothermal Reduction in TiO2 Under Vacuum

TiB2 powders were synthesized by borothermal reduction in nanoscale TiO2 with boron under vacuum. Reaction processes were investigated, and the effect of by-product B2O3 was evaluated. Results showed that TiO2 was firstly reduced by boron to form TiBO3 and Ti2O3, and then to produce TiB2 and B2O3 with increasing temperature. The reaction processes of TiB2 powders synthesis included two-step reduction in TiO2 by boron and the removal of B2O3. The presence of B2O3, which was previously reported as the most important factor in promoting the coarsening of ZrB2 and HfB2 powders by borothermal reduction, did not lead to significant coarsening of TiB2 powders. Due to the minor effect of B2O3, TiB2 powders with small particle size and low oxygen content could be prepared by direct heat treatment of TiO2 and boron at 1550 degrees C under vacuum for 1h. The particle size and oxygen content of synthesized TiB2 powders were similar to 0.9m and similar to 1.7wt%, respectively.