Enhancement of oxygen exchange at the hetero interface of (La,Sr)CoO3/(La,Sr)2CoO4 in composite ceramics

Maya Sase, Keiji Yashiro, Kazuhisa Sato, Junichiro Mizusaki, Tatsuya Kawada, Natsuko Sakai, Katsuhiko Yamaji, Teruhisa Horita, Harumi Yokokawa

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112 Citations (Scopus)

Abstract

The preferential reaction path for oxygen isotope exchange was investigated on a large-grained polycrystalline (La0.6Sr0.4)CoO3 with (La,Sr)2CoO4 grains dispersed as the secondary phase. The isotope exchange experiment was performed at 773 K in 18O enriched oxygen of 0.2 × 105 Pa. Three-dimensional imaging of Secondary Ion Mass Spectrometry (SIMS) was carried out to visualize the isotope distribution. The SIMS image suggested that there are fast oxygen-incorporation paths along the heterophase boundary of (La0.6Sr0.4)CoO3 / (La,Sr)2CoO4. The surface exchange coefficient, k for the heterophase boundary was roughly estimated by analyzing the depth profile of 18O. The calculated k was 8 × 10- 6 cm s- U1, which is larger than the value of k for the surface of single phase La0.6Sr0.4CoO3 by three orders of magnitude.

Original languageEnglish
Pages (from-to)1843-1852
Number of pages10
JournalSolid State Ionics
Volume178
Issue number35-36
DOIs
Publication statusPublished - 2008 Feb 15

Keywords

  • (La,Sr)CoO
  • LaSrCoO
  • SIMS
  • SOFC cathode
  • oxygen isotope exchange

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

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