resumo
Stabilized fluorites and pyrochlores with different types of substitution in the (Nd2O3 - ZrO2 system (NdZrO)) have been studied by Raman spectroscopy, X-ray diffraction, and impedance spectroscopy methods. Ionic and proton conductivity maps for 9 compositions in the NdZrO system are presented. Oxygen partial pressure measurements show a typical ionic conductor behavior, with a significantly increase of conductivity for (Nd2-xZrx)Zr2O7+x/2 (x = 1.27) fluorite and (Nd2-xZrx)Zr2O7+x/2 ( x = 0.4, 0.2) pyrochlores. For the same compositions the strong luminescence was observed. Strong luminescence and high oxygen ion conductivity of these solid solutions can be associated with the presence of phases with the different degree of structural disorder (tetragonal phase, fluorite) in local nanodomains in fluorite or pyrochlore matrix in the ZrO2 - Nd2Zr2O7 region. Really, Raman spectra of (Nd2-xZrx)Zr2O7+x/2 ( x = 0.5 - 0.2) solid solutions demonstrated the fluorite + pyrochlore structural type in the short-range order. Fluorite nanodomains in pyrochlore matrix (ZrO2 - Nd2Zr2O region) resulting from an order-disorder transition can only be detected at a radiation wavelength comparable to the fluorite nanodomain size. Thus, using Raman spectroscopy the broad isomorphism range in theZrO(2) - Nd2Zr2O system has been shown to be nonuniform. (c) 2021 Elsevier Ltd. All rights reserved.
palavras-chave
CRYSTAL-STRUCTURE; OPTICAL-PROPERTIES; PYROCHLORE; ZIRCONIA; STABILITY; CERAMICS; MICROSTRUCTURE; NANOPARTICLES; TRANSPORT; FLUORITE
categoria
Electrochemistry
autores
Lyskov, NV; Shchegolikhin, AN; Stolbov, DN; Kolbanev, IV; Gomes, E; Abrantes, JCC; Shlyakhtina, AV
nossos autores
João Carlos de Castro Abrantes
Professor Adjuntoagradecimentos
The support of this work by the Russian Science Foundation (Project 18-13-00025 -XRD, luminescence, Raman spectroscopy data) is gratefully acknowledged. Conductivity measurements of the samples in dry and wet air were supported in accordance with the state task for IPCP RAS, state registration No. AAAA-A19-119061890019-5 and into frameworks of the state task for FRCCP Nanostructured systems of a new generation with unique functional properties.