Oxygen release behaviour of Ce(1-x)ZrxO2 powders and appearance of Ce(8-4y)Zr4yO(14-δ) solid solution in the ZrO2-CeO2-CeO1.5 system

Noriya Izu, Takahisa Omata, Shinya Otsuka-Yao-Matsuo

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58 Citations (Scopus)

Abstract

To clarify the existence of metastable phases in the ZrO2-CeO2-CeO1.5 system, evolved-oxygen gas analyses, (EGA), by heating a single phase of t′ and t″ (Ce(1-x)ZrxO2) with various compositions, x, in a reducing gas and successive oxidation were carried out repeatedly. The oxygen release behaviour of the t′ and t′ phases was very complicated. The single κ phases, (Ce(1-x)ZrxO2) with the composition, x=0.5 and 0.6, which were obtained by oxidizing the resulting pyrochlore as a precursor in O2 gas at 873 K, exhibited a sharp oxygen release at the lowest temperature; the composition range of K phase may be x=0.45∼0.65. A new tetragonal phase t*, (Ce(1-x)ZrxO2), which was attained by cyclic redox process together with annealing in O2 gas at 1323 or 1423 K, exhibited a sharp oxygen release at the highest temperature; the composition range of t* phase may be as wide as x=0.20∼0.65. A metastable solid solution expressed by a chemical formula of Ce(8-4y)Zr4yO(14-δ) (y=0∼1) possessing a CaF2-related structure appeared on deoxidation of the t* phase. A ternary phase diagram containing the t* and Ce(8-4y)Zr4yO(14-δ) solid solution was proposed.

Original languageEnglish
Pages (from-to)107-114
Number of pages8
JournalJournal of Alloys and Compounds
Volume270
Issue number1-2
DOIs
Publication statusPublished - 1998 May 29
Externally publishedYes

Keywords

  • CeO
  • Cerium zirconate
  • Oxygen release

ASJC Scopus subject areas

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

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