Composite oxide ionic conductors consisting of Zr_(0.85)Y_(0.15)O_(1.925)(YSZ)and La_(9.33)Si_(6)O_(26)(LSO)have been synthesized by a modified coprecipitation method.X-ray diffraction,electron microscope,and complex impedance were adopted to investigate the phase component,microstructures,and conductivities,respectively.The results show that the average grain sizes of the composite powders and as-sintered pellets are less than 20 nm and 200 nm,respectively.The conductivity of the composite materials composed of 94 wt%YSZ and 6 wt%LSO is 0.215 S/cm at 700℃.The conductivity of the composite is three times higher than that of the polycrystalline YSZ and has two orders in magnitude higher than that of the polycrystalline LSO at 700℃.By analyzing the impedance spectra and modulus spectra,the grain-boundary effect on the conductivity improvement is investigated and the conductive mechanisms of the composite materials are discussed.
In order to develop the applications of ore tailings, the glass ceramics were prepared by using a conventional melting-quenching-sintering process. The phase component, microstructures, magnetic properties and thermal conductivities of the prepared glass ceramics were investigated by using X-ray diffractometer, scanning electron microscopy, vibrating sample magnetometer and thermophysical properties tester, respectively. The results show that orthorhombic olivine-type phase and triclinic sunstone-type phase formed when the glass was annealed at 700 oC, the concentration of olivine-type and sunstone-type phases decreased, the spinel-type cubic phase occurred and the amount increased when the annealing temperatures increased. The magnetic properties from the cubic spinel ferrites were detected in the glass ceramics, and the related saturation magnetization increased with the annealing temperature increasing. The porous glass ceramics with magnetic property showed much lower thermal conductivity, compared with the non-magnetic porous glass-ceramic and the dense glass-ceramics.
