High sintering ability and electrical conductivity of Zn doped La(Ca)CrO3 based interconnect ceramics for SOFCs

In order to improve the sintering ability of La0.7Ca0.3CrO3−δ (LCC), which has been considered as the interconnect material for SOFC but needs rather high temperature to densification, the ceramic powder with a nominal composition of La0.7Ca0.3Cr0.95Zn0.05O3−δ (LCCZ) was prepared by auto-ignition process. The result was quite positive, that the specimens made by pressing the powder under 360 MPa and sintered at 1200 °C in air for 5 h showed a relative density of 95.2%. The electrical conductivity of LCCZ sintered at 1400 °C for 5 h reached 47.5 S cm−1 in air and 6.15 S cm−1 in hydrogen at 800 °C, which were much higher than the values of LCC. The thermal expansion coefficient of LCCZ was 11.5 × 10−6 K−1, which well matches other components of SOFC.