Vacuum Synthesis of Nanocrystalline TiC at a Low Carbothermal Reduction Temperature

Ultrafine TiC powders with a grain size of about 25 nm were synthesized from nanoanatase TiO2/carbon black mixtures by mechanical activation-assisted vacuum carbothermal reduction (MCR) reaction. The effects of mechanical activation and carbon sources on TiO2 carbothermal reduction (CR) were also investigated. Results indicated that the CR of nanoTiO2 was enhanced after pre-milling of the starting powders. The synthesis temperature and holding time of TiC decreased from 1500 °C to 1300 °C and from 4 h to 2 h, respectively. However, phase evolution analysis of the reaction showed that mechanical activation did not alter the phase evolution sequences of the TiO2 CR. In addition, the relative weight loss of powders in increasing temperatures indicated that nanoTiO2 MCR can be divided into three stages, in which the reaction rate of the second stage is found to be the fastest. The study on the effect of different carbon sources on the MCR of nanoTiO2 showed that the use of nanocarbon black as carbon source can cause MCR to react more thoroughly than the use of graphite and active carbon.