Characterisation of scheelite LaW0.16Nb0.84O4.08 ion conductor by combined synchrotron techniques: Structure, W oxidation state and interdiffusion

Francesco Giannici, Antonino Martorana, Giovanna Canu, Giorgia Confalonieri, Monica Dapiaggi, Vincenzo Buscaglia, Maria Teresa Buscaglia, Alessandro Longo

Risultato della ricerca: Articlepeer review

Abstract

Scheelite-type materials such as LaNbO4 are increasingly attracting attention as a possible alternative to the most common fluorite and perovskite structure as ion conductors. However, they are much less used and investigated. The introduction of tungsten in lanthanum orthoniobate leads to conduction properties that are compatible with oxygen ion conductivity. In this paper, we studied the effect of the introduction of tungsten in the LaNbO4 structure. High resolution X-ray diffraction showed that in LaNb1-xWxO4+x/2 with x = 0.16 the monoclinic distortion is largely suppressed and the tetragonal phase is predominant at room temperature. By XANES/EXAFS we proved that tungsten is in its 6+ valence state and no W5+ was detected. With X-ray microspectroscopy, we studied in detail with a submicrometre-probe the interdiffusion and degradation processes taking place between the material and LSM, a common electrode material, during their long-term contact at high temperatures.
Lingua originaleEnglish
Numero di pagine6
RivistaJournal of Alloys and Compounds
Stato di pubblicazionePublished - 2020

All Science Journal Classification (ASJC) codes

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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