Mechanochemical synthesis of nano-structured TiC from TiO_2 powders

摘要

Nano-structured TiC was successfully synthesized from mixtures of TiO_2 and graphite through highenergy mechanical milling and subsequent heat treatment at a temperature that was considerably lower than that used in conventional carbothermal reduction synthesis of TiC. TiO_2 powders mixed with graphite were milled in a planetary ball mill for 30-90 h. The milled mixtures were then heat treated at 1200℃ and 1300℃ for 60 min. The as-milled and heat treated powders were characterized using SEMEDAX,DTA, and XRD techniques. As revealed in SEM, agglomeration was found to be more pronounced after 30 h milling. Even though the formation of TiC was not detected in as-milled powders milled for durations between 30 h and 90 h, TiC appeared in the powder mass after heat treatment as revealed by the XRD patterns. The crystallite size of TiC as a function of milling time was estimated from the XRD data using Scherrer equation and it was found to be increased with increasing milling time after heat treatment.