Oxygen diffusion in niobia-doped zirconia as surrogate for oxide film on Zr-Nb alloy: AC impedance analysis

Teppei Yamana, Tatsumi Arima, Takatoshi Yoshihara, Yaohiro Inagaki, Kazuya Idemitsu

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

The oxygen conductivities and crystallographic properties of niobia-doped yttria-stabilized tetragonal zirconia with 0.0-2.6 wt% Nb2O 5 were evaluated by the AC impedance analysis and the X-ray diffraction measurement, respectively. The tetragonality of zirconia increased with niobia content and approached ∼1.017 while the tetragonal-to-monoclinic phase transition occurred above ca. 1 wt% Nb2O5. On the other hand, oxygen conductivities of bulk and grain-boundary (GB) decreased with increasing niobia content. The bulk conductivity controlled the total ionic conductivity at high temperatures, and its activation energy had smaller dependence on temperature than that of GB. In addition to the effect of [VO] depletion by niobia addition, the behaviors of bulk and GB conductivities might be explained by the decrease of mobility of oxygen ion due to Coulomb repulsion between Nb5+ and VO and by no segregation of Nb ions in the space-charge layers, respectively.

Original languageEnglish
Pages (from-to)608-613
Number of pages6
JournalJournal of Nuclear Materials
Volume443
Issue number1-3
DOIs
Publication statusPublished - Oct 29 2013

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Materials Science(all)
  • Nuclear Energy and Engineering

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