Vacuum Annealing of TaC Nanopowders

Abstract

Nanopowders with different average particle sizes of 20 to 40 nm are obtained by milling TaC microcrystalline powder. Analytical chemistry, X-ray diffraction, scanning electron microscopy, and the Brunauer–Emmett–Teller approach are used to study the effect the average particle size of TaC nanopowder and the temperature of its vacuum annealing (400–1400°С) had on the chemical and phase composition, morphology, and average particle size of the powder after annealing. It is found that the vacuum annealing of TaC nanopowders over the considered range of temperatures is accompanied by their decarbonization as a result of the interaction between carbon and impurity oxygen. It is shown that a rise in the temperature of annealing of TaC nanopowder is accompanied by an increase in both its size of particles and its decarbonization. As a result not only does the composition y of TaCy carbide change, but the phase composition of the entire powder changes as well. TaC nanopowder becomes microcrystalline after vacuum annealing at temperatures of 1200°C and above.