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A novel route to enhance the sinterability and its effect on microstructure, conductivity and chemical stability of BaCe0.4Zr0.4Y0.2O3-δ proton conductors
Published in Elsevier Ltd
2018
Volume: 216
   
Pages: 250 - 259
Abstract
BaCeO3 based perovskites exhibit highest protonic conductivity in their class but suffer from low chemical stability. Addition of more stable BaZrO3 to BaCeO3 has been explored to obtain a good combination of conductivity and chemical stability. BaZrO3, however, is unfavourable towards densification due to its poor sinterability. In this study, a two-step sintering process and Zn addition have been explored vis-à-vis conventional sintering to obtain dense Y-doped BaCeO3-BaZrO3 solid solution (BaCe0.4Zr0.4Y0.2O3-δ) at comparatively lower temperatures. The conventional single-step sintering at 1450 °C for different sintering times (5, 10, 15 h) could not provide a dense sample. The two-step sintering process (1550 °C-5 min, 1450 °C-15 h), on the other hand, yielded a relative density of 95%. Addition of 4 mol.% Zn resulted in high sintered density (97%) at 1300 °C though it was not effective at 1200 °C due to insufficient shrinkage (densification). Zn addition also improved the chemical stability against CO2. The grain size of the sintered samples decreased with decreasing sintering temperature and or time. As a result the specific grain boundary conductivity decreased with decreasing sintering time. The overall conductivity was higher in the two-step processed sample compared to the Zn-doped sample. © 2018 Elsevier B.V.
About the journal
JournalData powered by TypesetMaterials Chemistry and Physics
PublisherData powered by TypesetElsevier Ltd
ISSN02540584
Open AccessNo
Concepts (18)
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    BARIUM ZIRCONATE
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    CERIUM COMPOUNDS
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    Chemical stability
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    Electric conductivity
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    Grain boundaries
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    Perovskite
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    Sintering
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    Solid oxide fuel cells (sofc)
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    Zinc
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    CONVENTIONAL SINTERING
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    GRAIN BOUNDARY CONDUCTIVITY
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    Lower temperatures
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    PROTON CONDUCTORS
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    PROTON-CONDUCTING OXIDES
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    PROTONIC CONDUCTIVITIES
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    Sintering temperatures
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    TWO-STEP SINTERING PROCESS
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    Yttrium compounds