Effect of zinc oxide on yttria doped ceria

Solid electrolyte ceramics consisted of ceria, yttria and zinc oxide has been synthesized through solid state reaction. With the zinc oxide content over 0.4 mol.%, this material is able to achieve a relative density of 96% at 1375 °C, about 200 °C lower than that without zinc oxide. The result of XRD reveals that the lattice parameter increased with the concentration of zinc oxide up to 0.6 mol%, suggesting its solubility limit for fluorite structure of ceria. It is also found that this doping level is coincident with that where it has the highest ionic conductivity. Furthermore, it is detected by EDS that the excess zinc oxide tends to agglomerate and locate on the surface of sintered sample when the addition exceeds the solubility limit.