Thermal plasma chemical synthesis of powders

Thermal plasma processing has been increasingly used to synthesize submicron powders of high-purity ceramics and metals. The high temperatures generated with the plasma provide a vapor phase reaction zone for elements with high boiling points and refractory materials. An overview is presented on the general plasma technology used in synthesis and on the properties of plasma powders

Thermodynamics of the tantalum-carbon-chlorine-hydrogen system applied to the CVD of carbide/carbon composite materials

Complex equilibrium thermodynamic calculations using the computer code SOLGASMIX-PV were performed for the Ta-Cl-H and Ta-C-Cl-H systems in order to evaluate the chemistry associated with the chemical vapor deposition of Ta, Ta/sub 2/C, and TaC on graphite yarn and woven structures. Results of the thermodynamic calculations were compared with coated materials prepared by hydrogen reduction of TaCl/sub 5/(g) and C/sub 3/H/sub 6/(g) between 1025 and 1223/sup 0/K using a variety of reaction gas compositions