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 language | English |
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Pages (from-to) | 1843-1852 |
Number of pages | 10 |
Journal | Solid State Ionics |
Volume | 178 |
Issue number | 35-36 |
DOIs | |
Publication status | Published - 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