Browsing by Author "Belov, DA"

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    Interstitial oxide ion conduction in (Ln (2-x) Zrx) Zr2O7+ delta (Ln= Nd, Sm)
    (International Union of Crystallography, 2012-08-29) Shlyakhtina, AV; Belov, DA; Knotko, AV; Avdeev, M; Kolbanev, IV; Streletskii, AN; Shcherbakova, LG
    We have studied the structure and transport properties of (Ln2-xZrx)Zr2O7+x/2 (Ln= Nd, Sm; x=0; 0.2; 0.32; 0.39; 0.48; 0.67; 0.78; 0.96; 1.14; 1.27) solid solutions, which lie in the ZrO2-Ln2Zr2O7 (Ln= Nd, Sm) isomorphous miscibility range (33.3, 29, 26.6, 25.3, 23.5, 20, 18, 15, 12, 10 mol% Ln2O3) in the Nd2O3-ZrO2 (NdZrO) and Sm2O3-ZrO2 (SmZrO) systems. Major attention has been focused on the structure and properties of pyrochlore-like (Ln2 xZrx)Zr2O7+x/2 (Ln=Nd, Sm) solid solutions with x = 0–0.78, which are thought to be potential interstitial oxide ion conductors. The crystal structure of the solid solutions has been investigated by X-ray and neutron diffraction techniques using Rietveld refinement, and their microstructure has been examined by SEM. The excess oxygen content of the (Ln2-xZrx)Zr2O7+x/2 (Ln= Nd, Sm; x=0.2;0.32) pyrochlore-like solid solutions has been determined by thermal analysis and mass spectrometry in a reducing atmosphere (H2/Ar-He). The transport properties of the solid solutions in the two systems have been studied by impedancespectroscopy in air. © International Union of Crystallography
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    Oxide ion transport in (Nd2−xZrx)Zr2O7+δ electrolytes by an interstitial mechanism
    (Elsevier, 2014-08-05) Shlyakhtina, AV; Belov, DA; Knotko, AV; Avdeev, M; Kolbanev, IV; Vorobieva, GA; Karyagina, OK; Shcherbakova, LG
    We have studied the structure and transport properties of ten (Nd2−xZrx)Zr2O7+x/2 (x = 0–1.27) solid solutions, which lie in the ZrO2–Nd2Zr2O7 isomorphous miscibility range. Major attention has been focused on the pyrochlore-like (Nd2−xZrx)Zr2O7+x/2 solid solutions with x = 0–0.78, which are thought to be potential interstitial oxide ion conductors. The X-ray and neutron diffraction results demonstrate that the (Nd2−xZrx)Zr2O7+x/2 (x = 0–1.27) solid solutions undergo an order–disorder (pyrochlore–defect fluorite) structural phase transition. The (Nd2−xZrx)Zr2O7+x/2 (x = 0.2–0.78) have the bulk conductivity, ∼(1.2–4) × 10–3 S/cm at 750 °C, which is two orders of magnitude higher than that of the ordered pyrochlore Nd2Zr2O7. An attempt has been made to determine the interstitial oxygen content of (Nd2−xZrx)Zr2O7+x/2 (x = 0.2; 0.67) in a reducing atmosphere using thermogravimetry and mass spectrometry. It has been shown that no reduction occurs in the NdZrO system, where neodymium has only one oxidation state, 3+. © 2014, Elsevier B.V.