Effects of Vacuum Annealing on the Particle Size and Phase Composition of Nanocrystalline Tungsten Carbide Powders

摘要

The effects of the vacuum annealing temperature (400-1400°C) on the phase and chemical com- position, particle size, and microstresses of the nanocrystalline powders of tungsten carbide WC with 20- 60 nm particles were studied by X-ray diffraction and electron microscopy. Vacuum annealing of WC nano- powders at T_(ann) ≤ 1400°C was accompanied by decarbonization, resulting from the interaction of carbon with the oxygen impurity. Changes in the chemical composition of the nanocrystalline powder of tungsten carbide led to changes in its phase composition. The annealing was accompanied by growth of powder particles due to the aggregation of nanoparticles and by a decrease of microstresses.