In order to develop interconnect ceramics for intermediate temperature solid oxide fuel cells (IT-SOFCs), perovskite compounds, Gd1−xCaxCrO3 (x = 0 to 0.3), were prepared by an auto-ignition process and characterized. X-ray diffraction analysis indicated that a single perovskite phase was obtained as Ca2+ content (x value) was lower than 0.3, while a second phase appeared at x = 0.4. The lattice parameters of the unit cell decrease with increasing the substitution Ca2+ for Gd3+. The particle sizes of Gd0.7Ca0.3CrO3 powders were in the range of 20 of 50nm observed by transmission electron microscopy. The powders exhibited better sintering ability and could reach 94.8% relative density at 1400C for 4h in air. The DC four probe technique measurement indicated that the electrical conductivities of the specimens increased with increasing Ca2+ content for x-values below 0.3 but remarkably dropped when x = 0.4, which might be attributed to the formation of the second phase with lower conductivity in the materials. Gd0.7Ca0.3CrO3 with a density of 94% exhibited an electrical conductivity of 24S/cm in air and 7.5S/cm in H2 (99.999%) at 700C respectively, which was about 50% more than that of the commonly used lanthanum chromite (La0.7Ca0.3CrO3). It will be suitable to be interconnect material for IT-SOFCs.

Synthesis and Electrical Conductivity of Perovskite Gd1−xCaxCrO3 (x = 0 to 0.3) by Auto-Ignition Process. H.H.Zhong, X.L.Zhou, X.Q.Liu, G.Y.Meng: Solid State Ionics, 2005, 176[11-12], 1057-61