TY - JOUR
T1 - Electrical conductivity of metastable K-CeZrO4 phase possessing ordered arrangement of Ce and Zr ions
AU - Izu, Noriya
AU - Kishimoto, Haruo
AU - Omata, Takahisa
AU - Yao, Takayuki
AU - Otsuka-Yao-Matsuo, Shinya
N1 - Copyright:
Copyright 2005 Elsevier B.V., All rights reserved.
PY - 2001/9/12
Y1 - 2001/9/12
N2 - Electrical conductivity σt of metastable κ-CeZrO4 possessing ordered arrangement of Ce and Zr ions in a manner similar to a pyrochlore-type was measured as a function of temperature and time, and compared with tetragonal metastable t′-(Ce0.5Zr0.5)O2 and t′meta-(Ce0.5Zr0.5)O2 phases possessing random arrangement of the cations. The K disk was prepared by reoxidizing a pyrochlore-type precursor in O2 gas at 873 K. The σt as measured for the κ-CeZrO4 was reproducible as a function of temperatures between 957 and 1190 K. At increasing temperatures above 1233 K, the σt decreased gradually with time due to the phase transition: κ → t′, and became consistent with the t′. Although the κ-CeZrO4 phase is thermodynamically less stable than the t′-(Ce0.5Zr0.5)O2, it was virtually stable up to around 1233 K. It was found from the change in the σt due to the phase transition that the σt for the metastable κ-CeZrO4 was an order of magnitude higher than that for the t′ and was similar to that for the t′meta. It was previously reported that a phase transition, t′meta → t′, occurred above 1143 K. The phase transition, κ → t′, accompanied by redistribution of the cations appeared to occur at higher temperatures than that for t′meta → t′ leaving random cation arrangement.
AB - Electrical conductivity σt of metastable κ-CeZrO4 possessing ordered arrangement of Ce and Zr ions in a manner similar to a pyrochlore-type was measured as a function of temperature and time, and compared with tetragonal metastable t′-(Ce0.5Zr0.5)O2 and t′meta-(Ce0.5Zr0.5)O2 phases possessing random arrangement of the cations. The K disk was prepared by reoxidizing a pyrochlore-type precursor in O2 gas at 873 K. The σt as measured for the κ-CeZrO4 was reproducible as a function of temperatures between 957 and 1190 K. At increasing temperatures above 1233 K, the σt decreased gradually with time due to the phase transition: κ → t′, and became consistent with the t′. Although the κ-CeZrO4 phase is thermodynamically less stable than the t′-(Ce0.5Zr0.5)O2, it was virtually stable up to around 1233 K. It was found from the change in the σt due to the phase transition that the σt for the metastable κ-CeZrO4 was an order of magnitude higher than that for the t′ and was similar to that for the t′meta. It was previously reported that a phase transition, t′meta → t′, occurred above 1143 K. The phase transition, κ → t′, accompanied by redistribution of the cations appeared to occur at higher temperatures than that for t′meta → t′ leaving random cation arrangement.
KW - Ceria
KW - Electrical conductivity
KW - Fluorite-related structure
KW - Metastable phase
KW - Phase transition
KW - Pyrochlotre-type
KW - Zirconia
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U2 - 10.1016/S1468-6996(01)00074-2
DO - 10.1016/S1468-6996(01)00074-2
M3 - Article
AN - SCOPUS:0042504879
VL - 2
SP - 443
EP - 448
JO - Science and Technology of Advanced Materials
JF - Science and Technology of Advanced Materials
SN - 1468-6996
IS - 3-4
ER -