Synthesis of TiB₂ from a carbon-coated precursors method

This article deals with the synthesis of TiB₂ from carbon-coated TiO₂ precursors with the addition of B₄C. The carbon-coated precursors method alters the reaction process, compared with the conventional mixing of reactants, to produce high-quality TiB₂ powders. The produced powders have a single phase, a submicron particle size (~0.3 to 0.8 μm), regular shape, loose agglomeration, and low level of contaminations (less than 0.5 wt% carbon and 0.6 wt% oxygen). The formation mechanism proposed is based on experimental results and thermodynamic evaluations. For comparison, the powders obtained from the mixture of reactants show higher agglomeration, a large particle size (>1 μm), high level of contaminations (0.7 wt% carbon and 1.1 wt% oxygen), and difficulty to control the reaction process (formation of TiBO₃ and Ti₂O₃ as the intermediate phases). The synthesized powders from the precursors method can be hot pressed to a relative density of ~94.5% with the formation of platelike grains at 1800°C under a pressure of 35 MPa without additives.