Studies on synthesis and characterization of titanium diboride powders

Abstract

In the present work, single phase titanium diboride (TiB2) powders were prepared by thermal plasma assisted boro/carbothermal reduction method. TiB2 powder was synthesized by reduction of titanium dioxide(TiO2) with activated charcoal and boron carbide(B4C) in an argon atmosphere. To compensate for the evaporation loss of boron source and ensure the complete conversion into TiB2, varying amounts of B4C (0-15 wt%) were added. The influence of excess addition of B4C on the composition and morphology of the product was studied. Phase evolution and microstructure of the synthesized powders were analysed by using different characterization techniques. X-ray diffraction (XRD) analysis revealed the presence of TiB2 along with a small proportion of unreacted carbon in the product with excess of 5-10 wt% B4C. TiO2 was completely converted to TiB2 when the B4C addition was increased to 15 wt%. These findings were further supported by Raman and Fourier Transform Infrared Spectroscopy (FTIR). Single phase TiB2 powders with particle size 5 mu m were successfully synthesized by adding 15 wt% excess B4C within 20 min. Scanning electron microscope(SEM) observation revealed aggregated TiB2 particles with a broad size of distribution. Overall, the results demonstrated that thermal plasma technique is a quick and efficient method to prepare high temperature ceramic material like TiB2.