Xiaoliang Zhou

Characterization of A-site excessive perovskite La0.7–xSmx+0.02Ca0.3CrO3–δ

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 °C 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 samarium. The conductivity of La0.6Sm0.12Ca0.3CrO3-δ was 33.6 S/cm in air at 700 °C 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 increased from 0 to 0.4, and they were close to that of Y doped ZrO2 (YSZ). La0.7–xSmx+0.02Ca0.3CrO3–δ (0.1≤x≤0.3) were good choices for intermediate temperature solid oxide fuel cells (IT-SOFCs) interconnect materials.