Electrical conductivity of metastable K-CeZrO4 phase possessing ordered arrangement of Ce and Zr ions

Noriya Izu, Haruo Kishimoto, Takahisa Omata, Takayuki Yao, Shinya Otsuka-Yao-Matsuo

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17 Citations (Scopus)

Abstract

Electrical conductivity σt of metastable κ-CeZrO4 possessing ordered arrangement of Ce and Zr ions in a manner similar to a pyrochlore-type was measured as a function of temperature and time, and compared with tetragonal metastable t′-(Ce0.5Zr0.5)O2 and t′meta-(Ce0.5Zr0.5)O2 phases possessing random arrangement of the cations. The K disk was prepared by reoxidizing a pyrochlore-type precursor in O2 gas at 873 K. The σt as measured for the κ-CeZrO4 was reproducible as a function of temperatures between 957 and 1190 K. At increasing temperatures above 1233 K, the σt decreased gradually with time due to the phase transition: κ → t′, and became consistent with the t′. Although the κ-CeZrO4 phase is thermodynamically less stable than the t′-(Ce0.5Zr0.5)O2, it was virtually stable up to around 1233 K. It was found from the change in the σt due to the phase transition that the σt for the metastable κ-CeZrO4 was an order of magnitude higher than that for the t′ and was similar to that for the t′meta. It was previously reported that a phase transition, t′meta → t′, occurred above 1143 K. The phase transition, κ → t′, accompanied by redistribution of the cations appeared to occur at higher temperatures than that for t′meta → t′ leaving random cation arrangement.

Original languageEnglish
Pages (from-to)443-448
Number of pages6
JournalScience and Technology of Advanced Materials
Volume2
Issue number3-4
DOIs
Publication statusPublished - 2001 Sep 12

Keywords

  • Ceria
  • Electrical conductivity
  • Fluorite-related structure
  • Metastable phase
  • Phase transition
  • Pyrochlotre-type
  • Zirconia

ASJC Scopus subject areas

  • Materials Science(all)

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