93Nb NMR study of an ordered and a disordered non-stoichiometric niobium carbide

Abstract

Using pulse-modulated NMR spectroscopy of 93Nb, a non-stoichiometric niobium carbide, NbCy has been investigated. NMR spectra have been obtained for NbCy samples with different vacancy concentrations in the carbon sublattice. The NMR spectra of an ordered niobium carbide, NbC0.83, have been found to differ appreciably from those of a disordered one. The parameters of the quadrupole interactions have been calculated. The NMR spectral lines reflect the various types of environment of the niobium atoms. Short-range order in an ordered and a disordered niobium carbide has been identified. The presence of an ordered Nb6C5 phase has been confirmed.