Abstract
The synthesis of pure, submicron, crystalline TaC powder by the vapour-phase reaction of methane and TaCl5 has been studied in the range 1400–1600°C (1673–1873 K). Particular attention was given to the effect of process variables on particle characteristics. Dry collection and subsequent acid treatment of the powders were found necessary to yield a pure product. A minimum temperature of 1400°C was required for the reaction, but elevation to 1600°C had no apparent effect on the degree of conversion or the particle-size range. Electron micrographs showed the powders to have a very narrow particle-size range of from 0·02 to 0·07 μm. Over 45% of the particles were in the range 0·04-0·045 μm, and ∼80% in the 0·03–0·05 μm range. In general, the particles exhibited equidimensional shapes.
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