Studies on a supersonic thermal plasma expansion process for synthesis of titanium nitride nanoparticles

The paper reports studies on supersonic thermal plasma expansion process for rapid, controlled synthesis of titanium nitride nanoparticles with enhanced particle characteristics, by injecting TiCl4 and NH3 at two different reaction zones, namely hot zone and colder tail zone of a thermal plasma jet assisted chemical reactor. Two different chamber pressures of 30 mbar and 10 mbar were maintained to investigate the effect of pressure on the characteristics of the product particles. The nanoparticles synthesized by injecting reactants to the colder tail zone at 10 mbar chamber pressure show sub-10 nanometer average sizes with cubic shapes. On the other hand, particles synthesized by injecting the reactants to the hot zone shows better crystal structure and bigger size. The optical spectrums obtained from the injection zone indicate the presence of both atomic and ionic species in the plasma which are the growth precursors for the synthesis of titanium nitride particles. Plasma temperature at the injection zone was estimated from the plasma emission spectra by Atomic Boltzmann Plot method.