Characterization of A-site excessive perovskite La0.7-xSmx+0.02Ca0.3CrO3-δ
来源期刊：JOURNAL OF RARE EARTHS2009年第2期
论文作者：LIU Xingqin MENG Guangyao JIANG Cairong ZHOU Xiaoliang DENG Feijun MA Jianjun
Key words：A-site excessive perovskite; auto-ignition process; conductivity; interconnect materials; IT-SOFCs; rare earths;
Abstract: La0.7-xSmx+0.02Ca0.3CrO3-δ(0≤x≤0.4) powders with A-site excessive perovskite structure were synthesized by auto-ignition process and characterized. X-ray diffraction (XRD) patterns of samples after sintering at 1400℃ for 4 h were indexed as tetragonal structure. The relative densities were all above 96% although decreased slightly with the increasing content of samarium, indicating that the excessive A-site element was helpful to enhance their sinterability. Conductivities of the specimens in air increased with increasing content of samar-ium. The conductivity of La0.6Sm0.12Ca0.3CrO3-δ was 33.6 S/cm in air at 700 ℃ which was about 1.7 times as high as that of La0.7Ca0.3CrO3-δ (20.1 S/cm). Average thermal expansion coefficients (TECS) of the specimens increased from 11.06×10-6 to 12.72×10-6 K-1 when x in-creased from 0 to 0.4, and they were close to that of Y doped ZrO2 (YSZ). La0.7-xSmx+0.02Ca0.3CrO<3-δ>(0.1≤x≤0.3) were good choices for in-termediate temperature solid oxide fuel cells (IT-SOFCs) interconnect materials.
LIU Xingqin1，MENG Guangyao1，JIANG Cairong1，ZHOU Xiaoliang1，DENG Feijun1，MA Jianjun1
(1.Department of Materials Science and Engineering,University of Science and Technology of China,Hefei 230026,China)
Abstract:La0.7-xSmx+0.02Ca0.3CrO3-δ(0≤x≤0.4) powders with A-site excessive perovskite structure were synthesized by auto-ignition process and characterized. X-ray diffraction (XRD) patterns of samples after sintering at 1400℃ for 4 h were indexed as tetragonal structure. The relative densities were all above 96% although decreased slightly with the increasing content of samarium, indicating that the excessive A-site element was helpful to enhance their sinterability. Conductivities of the specimens in air increased with increasing content of samar-ium. The conductivity of La0.6Sm0.12Ca0.3CrO3-δ was 33.6 S/cm in air at 700 ℃ which was about 1.7 times as high as that of La0.7Ca0.3CrO3-δ (20.1 S/cm). Average thermal expansion coefficients (TECS) of the specimens increased from 11.06×10-6 to 12.72×10-6 K-1 when x in-creased from 0 to 0.4, and they were close to that of Y doped ZrO2 (YSZ). La0.7-xSmx+0.02Ca0.3CrO<3-δ>(0.1≤x≤0.3) were good choices for in-termediate temperature solid oxide fuel cells (IT-SOFCs) interconnect materials.
Key words:A-site excessive perovskite; auto-ignition process; conductivity; interconnect materials; IT-SOFCs; rare earths;
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