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authors |
Macias, J; Yaremchenko, AA; Frade, JR |
|
nationality |
International |
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journal |
JOURNAL OF ALLOYS AND COMPOUNDS |
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author keywords |
Strontium vanadate; Perovskite; Electrical conductivity; Thermal expansion; Redox stability; SOFC anode |
|
keywords |
OXIDE FUEL-CELLS; CRYSTAL-STRUCTURE; SOLID-SOLUTIONS; SOFC ANODE; PEROVSKITE STRUCTURE; SRVO3; EXPANSION; PYROVANADATES; TEMPERATURE; PERFORMANCE |
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abstract |
The reversibility of redox-induced phase transformations and accompanying electrical conductivity and dimensional changes in perovskite-type SrVO3-delta, a parent material for a family of potential solid oxide fuel cell anode materials, were evaluated employing X-ray diffraction, thermal analysis, dilatometry and electrical measurements. At 873-1273 K, the electrical conductivity of SrVO3-delta is metallic-like and 6-8 orders of magnitude higher compared to semiconducting V5+-based strontium pyrovanadate Sr2V2O7 and strontium orthovanadate Sr3V2O8 existing under oxidizing conditions. SrVO3-delta is easily oxidized to a pyrovanadate phase at atmospheric oxygen pressure. Inverse reduction in 10%H-2-90%N-2 atmosphere occurs in two steps through (5Sr(3)V(2)O(8) + SrV6O11) intermediate. As Sr3V2O8 is relatively stable even under reducing conditions, the perovskite phase and its high level of electrical conductivity cannot be recovered completely in a reasonable time span at temperatures <= 1273 K. Dilatometric studies confirmed that SrVO3 <-> Sr2V2O7 redox transformation is accompanied with significant dimensional changes. Their extent depends on the degree of phase conversion and, apparently, on microstructural features. (C) 2014 Elsevier B.V. All rights reserved. |
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publisher |
ELSEVIER SCIENCE SA |
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issn |
0925-8388 |
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year published |
2014 |
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volume |
601 |
|
beginning page |
186 |
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ending page |
194 |
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digital object identifier (doi) |
10.1016/j.jallcom.2014.02.148 |
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web of science category |
Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering |
|
subject category |
Chemistry; Materials Science; Metallurgy & Metallurgical Engineering |
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unique article identifier |
WOS:000334313500033
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