Thermal plasma synthesis of ceramic powders

The utilization of thermal plasma reactors for ceramic powder synthesis is described. The chemical reactions involved in the processes under the high temperatures generated in thermal plasmas are evaluated using Gibb's free energy minimization techniques. Silicon carbide, titanium carbide, titanium diboride, zirconium carbide, titanium carbide-iron and boron nitride have been synthesized using oxides as precursors. For each ceramic system the precursors are vaporized completely in the hot zone of the reactor where the plasma source is located; the vapors then travel down the temperature gradient to meet conditions where specific chemical reactions may occur (nucleation and/or growth); this is followed by rapid quenching to minimize back reactions or additional growth, thus enhancing the kinetic for the formation of meta-stable compounds that are consequently stabilized at room temperature. A description of the reactor system is presented.