This article is cited in 5 papers

Low dimensional systems

Effect of small particle sizes on the measured density of nanocrystalline powders of nonstoichiometric tantalum carbide TaC$_{y}$

A. S. Kurlov, A. I. Gusev

Institute of Solid State Chemistry, Urals Branch of the Russian Academy of Sciences, Ekaterinburg

Abstract: Nanocrystalline powders of the nonstoichiometric tantalum carbide TaC$_{y}$ (0.81 $\le y\le$ 0.96) with an average particle size in the range from 45 to 20 nm have been prepared using high-energy ball milling of coarse-grained powders. The density of the initial coarse-grained and prepared nanocrystalline powders of TaC$_{y}$ has been measured by helium pycnometry. The sizes of particles in tantalum carbide powders have been estimated using the X-ray diffraction analysis and the Brunauer–Emmett–Teller (BET) method. The density of TaC$_{y}$ nanopowders measured by helium pycnometry is underestimated as compared to the true density due to the adsorption of helium by the highly developed surface of the nanocrystalline powders. It has been shown that the difference between the true and measured densities is proportional to the specific surface area or is inversely proportional to the average particle size of the nanopowders. The large difference between the true and measured pycnometric densities indicates a superhydrophobicity of the tantalum carbide nanopowders.

Received: 02.02.2016

 English version: Physics of the Solid State, 2016, 58:8, 1687–1693

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