Preparation and investigation of Cu doped (Pr_0.5Nd_0.5)_0.7Ca_0.3CrO_3-δ ceramic interconnect materials

(Pr_0.5Nd_0.5)_0.7Ca_0.3Cr_1-xCuxO_3-δ (PNCCCx x=0, 0.5, 0.1, 0.15, 0.2) interconnect material and electro-lyte powders of Sm_0.2Ce_0.8O_1.9 (SDC) were synthesized by citric acid nitrates self-propagating combustion method.The phase and microstructure of the sintering samples were investigated by X-ray diffraction and scanning electr-on microscope, respectively. The electrical conductivity of the samples were measured by four-probe technique.The results indicated that there is no new-phase were detected after co-firing between Cu-doping PNCC and SDC at 1350°C for 5 h. In air or H₂ atmosphere, the conductivity of the sintering ceramics increasing with temperature, as well as the Cu-doped contents. At 800°C, the conductivity for PNCCC0.05 reached 37.54S/cm in air, and themaximum of PNCCC/SDC reached 44.52 S/cm in air 30.68 S/cm in H2, respectively. The average thermal expansion coefficient of the series ceramics is between10.4×10^-6 K^-1 to 10.8×10^-6K^-1 at the RT-1000°C, which is close to that of the SDC electrolyte. Our results indicate that the PNCCC compounds is a very promising interconnect material for intermediate solid oxide fuel cells.