| Yttria stabilized zirconia(YSZ) is an excellent solid electrolyte at high temperature because of its good oxygen ionic conductivity, chemical stability and high mechanical strength. At present, it has been widely used in solid oxide fuel cells (SOFCs), oxygen sensor and oxygen pump. And stable mixed ionic and electronic conducting oxides with the fluorite structure are attracting interest as candidates to be used as electrodes(mainly as anodes) in solid oxide fuel cells et al. The advantages of YSZ with TiO2 dopant mixed-conductors against the purely electronic ceramic electrodes are the following: a higher phase stability because of its solid state compatibility with the electrolyte, mixed oxygen ion-electronic conductivity.Generally speaking, the conductivity of solid electrolyte is strongly dependent on type and quantity of impurities in the starting powders, various sintering processing and microstructure of sintered samples.Nano-scale 8 mol% yttria stabilized zirconia(8YSZ) and YSZ with 8 mol% TiO2 dopant (8TiYSZ) powders were prepared by coprecipitation combined with azeotropic distillation process. Powder TG-DSC, X-ray diffraction, BET method and TEM were performed to characterize the powder properties. We prepared 8YSZ nano-powder with average particle size of 15nm when the reaction was under 60℃, the drop speed of mixture was 6 drop/min, and calcined at 700℃for 2h. By liquid phase doping of TiO2 sol, the 8Ti-YSZ solid solution was prepared.The densification of doping zirconia could be achieved by spark plasma sintering, the optimization of processing parameter were obtained through experiments. The density of 8YSZ and 8TiYSZ pellets reached the relative density of 99%, which sintered by SPS at 1250 and 1150℃for 3min, respectively.AC impedance spectroscopy was used to examine the electrical properties of different sintered pellets, the relationship between microstructure of ceramics and conductivity of grain and grain boundary was represented in this paper.
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