Microwave assisted synthesis, sinterability and properties of Ca-Zn co-doped LaCrO3 as interconnect material for IT-SOFCs

The interconnect materials La0.7Ca0.3Cr1−xZnxO3−δ (x=0, 0.01, 0.03, 0.05, 0.07) were prepared by a microwave assisted sol-gel auto-ignition process. The crystalline structures of the samples were characterized by X-ray diffraction (XRD) and the lattice parameters were evaluated with Rietveld method. For Ca-Zn co-doped LaCrO3 with x=0.03, the sintering activity was improved, and the relative density came up to 96.5% for the sample sintered at 1300 °C for 10 h. The electrical conductivity of the samples was increased from 21.1 S/cm to the maximum of 70.9 S/cm at 650 °C in air, with the x content increasing from 0.01 to 0.03. However, with x further increasing, the electrical conductivity was decreased. The average thermal expansion coefficient (TEC) of the samples at RT–1000 °C in air was ca. 10.0 × 10−6 K−1. All data indicated that the La0.7Ca0.3Cr1−xZnxO3−δ series ceramics would be potential candidate to be used as an interconnect materials for IT-SOFCs.