CAJ | 학술논문

In this study, ultrafine Ce0.8La0.2–xYxO1.9 (for x=0, 0.05, 0.10, 0.15, 0.20) powders were successfully prepared by the sol-gel method. The samples were characterized by fourier transform infrared (FTIR), thermogravimetric and differential scanning calo-rimetry (TG-DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), AC impedance and thermal expansion measure-ments. Experimental results indicated that highly phase-pure cubic fluorite electrolyte Ce0.8La0.2–xYxO1.9 powders were obtained after calcining at 600 °C. The as-synthesized powders exhibited high sintering activity, the Ce0.8La0.2–xYxO1.9 series electrolytes which have higher relative densities over 96%could be obtained after sintered at 1400 °C for 4 h. Ce0.8La0.15Y0.05O1.9 electrolyte sintered at 1400 °C for 4 h exhibited higher oxide ionic conductivity (σ800 oC=0.057 S/cm), lower electrical activation energy (Ea=0.87 eV) and moder-ate thermal expansion coefficient (TEC=15.5×10?6 K?1, temperature range 25–800 °C).