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 samarium. The conductivity of La0.6Sm0.12Ca0.3CrO3_swas 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 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.
A dense La0.8Sr0.2Ga0.83Mg0.17O2.815 electrolyte in pure perovskite phase was prepared by a polyacrylic acid assisted solid state reaction method, and the effects of La source on the structure and electrochemical performance were also studied. By means of XRD and SEM, the structure of this material was characterized, and the electrochemical properties were studied through AC impedance diagram. The results show that the sample presents a single perovskite-type phase after sintering at 1 450 ℃ and the relative density is 94%. The specimen has the lower activate energy and higher electrical conductivity at 600 ℃. There are two different activation energy at the turning point of 650 ℃, which are 74.6 and 42.4 kJ·mol-1, respectively. The electrical conductivity is 0.057 S·cm-1 and 0.017 S·cm-1 at the temperature of 800 ℃ and 600 ℃, respectively.
