Synthesis and structural characterization of titanium oxides and composites by thermal plasma oxidation of titanium carbide

In-flight TiC micron powders were oxidized in an aerosol reactor under heating by Ar-O-2 thermal plasma. The TiC micron powders can be oxidized efficiently in the Ar-O-2 plasma and the degree of oxidation can be controlled effectively by the oxygen input in the plasma gases. A full oxidation of the TiC powder was achieved at a high oxygen input giving rise to pure TiO2 powder products, while a partial oxidation under a moderate oxygen produced TiO2-TiC composites. The TiO2 particles generated by this process consist of well-defined mono-dispersed TiO2 micron spheres and nanosize powders, and are characterized by the high degree of crystallization (anatase and rutile), while the partially oxidized products consist of micron spheres of the intra-particulate composites of TiO2-TiC with TiC cores and rutile-TiO2 shells. This novel process has the potential to be applied in generating structural and functional coatings or films of TiO2 and TiO2-TiC micron composite by a plasma spray process. (C) 2002 Elsevier Science B.V. All rights reserved.