Formation of titanium nanoparticles from a titanium tetrachloride plasma

Abstract

The formation of titanium nanoparticles from plasmas in mixtures of titanium tetrachloride, argon and hydrogen is examined using three approaches: chemical equilibrium calculations, chemical kinetic calculations and a nucleation-coupled model of particle formation coupled to chemical kinetic equations. The results indicate that production of solid titanium particles requires a non-equilibrium process, such as is obtained using a rapid quench of the plasma. It is calculated that titanium yields approaching 100% are possible for sufficiently large residence times at a high temperature, and sufficiently rapid quench rates. The residence time and quench rate conditions are less stringent for high ratios of argon to titanium tetrachloride in the initial gas mixture. Adding hydrogen to the gas mixture leads to less stringent residence time, but more stringent quench rate conditions.