Synthesis of ceramic nanoparticles with non-equilibrium crystal structures and chemical compositions by controlled thermal plasma processing

The synthesis of functional nanostructured powders has been developed through reactive thermal plasma processing. Nanosized particles of titanium oxide powder with high crystallinity and non-equilibrium chemical composition were synthesised by one-step processing based on the oxidation of solid and liquid precursors. Spherical carbon powders were treated in a reactive thermal plasma. Crystallinity, chemical composition, and surface morphology were changed in plasma-treated carbon powders. Plasma-treated carbon powders were used as the anode of a lithium-ion rechargeable battery, and improvements in discharge capacity and efficiency were recognized. The generation of pulse-modulated RF inductively coupled plasmas (PM-ICPs) was developed for the first time. The non-equilibrium states were recognized at the instances of pulse-on and pulse-off, and the concentration of chemically active radical species was increased. This offers a unique physico-chemical condition for materials processing. (C) 2008 The Ceramic Society of Japan. All rights reserved.