Core-shell micron-scale composites of titanium oxide and carbide formed through controlled thermal-plasma oxidation

Core-shell structured micron-scale spheres of titanium oxide and carbide were prepared by the controlled in-flight oxidation of a powder of irregularly shaped titanium-carbide particles in an argon-oxygen thermal plasma. Mono-dispersed core-shell particles with rutile shells and TiC cores were formed by an intermediate-rate input of oxygen to the plasma gas. The partial oxidation of the TiC particles in the liquid phase was accompanied by spheroidization of the surface oxide melt, thus giving rise to a core-shell composite under rapid quenching. TiO2-TiC core-shell composites have potential as new materials for roles such as light-scattering media, photo-catalysts, and electro-rheorogical fluids. (C) 2002 Elsevier Science B.V. All rights reserved.