Preparation of tungsten carbide nanopowders by self-propagating high-temperature synthesis

Fine-particle tungsten carbide powders are produced from tungsten(VI) oxide by self-propagating high-temperature synthesis. The starting-mixture composition is shown to have a significant effect on the phase composition, morphology, and particle size of the WC powder. A procedure is described for recovering tungsten carbide from intermediate products using chemical dispersion. The influence of the dispersion agent on the morphology and particle size of the resultant powder is examined. The results indicate that the use of organic solvents for chemical dispersion prevents the formation of solid agglomerates, enhances the dissolution rate of impurities and defect-rich intercrystalline layers, and makes it possible to obtain tungsten carbide powders with a predominant particle size no greater than 0.05-0.2 mum.