Carbothermal Preparation of Ultra-fine TiB_2 Powders Using Solution-Derived Precursors via Sol-gel Method

摘要

Ultra-fine titanium diboride (TiB_2) powders have been prepared by Carbothermal reduction reactions in TiO_2-B_2O_3-C system using tetrabutyl titanate, boric acid and phenolic resin as the solution-derived precursors. The reactions were substantially completed at relatively lower temperature (<1400℃) and the resulting products had a smaller average crystallite size (< 200 nm). However, below 1100℃, titanium carbide was the predominant phase and the relative content decreased with the rise of temperature. The thermodynamic change in TiO_2-B_2O_3-C system was mainly studied by TG-DTA and the mechanism of synthesis of TiB_2 was discussed. The crystallite size and morphology of the synthesized powders were characterized by SEM and TEM.