Preparation and performance of novel ceramic interconnect materials (Pr_0.5Nd_0.5)_0.7Ca_0.3 CrO_3-δ - Sm_0.1Gd_0.1Ce_0.8O_1.9

A composite of (Pr_0.5Nd_0.5)_0.7Ca_0.3 CrO_3-δ(PNCC) - Sm_0.1Gd_0.1Ce_0.8O_2-δ (SGDC) interconnect materials was synthesized by a sol-gel auto-ignition process. The phase and microstructure of the sintering sample were analyzed by X-ray diffraction and scanning electron microscope, respectively. The electrical conductivity of the samples was measured by four-probe technique. The results indicated that PNCC was chemically stable against reaction with SGDC at high temperatures. For 5% (in mass) SGDC, the relative density of the sample was 97.1% after sintering at 1 400°C for 5 h, and the electrical conductivity of the sample reached 47 S/cm in air and 4 S/cm in H₂ at 700°C. The average thermal expansion coefficient of the sample was 10.4 × 10^-6 K^-1 at room temperature to 1000°C, which is close to that of electrolyte. Results indicate that the PNCC/SGDC composite is a very promising interconnect material for intermediate solid oxide fuel cells.