Exploring the impact of pH and temperature on TiC nanopowders syntesized via sol-gel and subsequent crystallization by carbothermal reduction method

Abstract

In the present study, titanium carbide powders with suitable morphology and nanometer particle size were synthesized by the sol-gel method to investigate the parameters affecting the properties of sol and the final powder. The initial sol was prepared in a four-component system of alkoxide-water-alcohol-citric acid based on the chemical process of sol-gel. study of sol properties showed that pH was the most important factor in the control of sol conditions and particle size so that at low pHs, due to low concentration of OH- ions and reduced viscosity, it was easier to control the particles size. Accordingly, the results of the Dynamics Light Scattering (DLS) showed that at low pHs, the particles size was below 10 nm. According to the zeta potential diagram and by examining the conditions of sol at different pHs, 4.5 was determined as the optimal pH and to prevent the bonding of particles within the sol, ammonium polycarboxylate dispersant was used. The temperature at which particles were formed was determined using Differential thermal analysis (DTA) and Thermal gravimetric analysis (TG). X-ray diffraction (XRD) patterns showed the presence of a completely amorphous phase at 700˚C. It was also observed that with increasing temperature, TiC crystallization started from 1200˚C and ended at 1400˚C. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) micrographs at 1400˚C showed the completely spherical morphology of particles of nanometer size so that no agglomerate was observed.