Al_2O_3掺杂对YSZ固体电解质烧结及电性能的影响

Effects of Alumina on the Sintering and Conductivity of Yttria-Stabilized Zirconia

研究了用常规共沉淀法掺杂Al_2O_3对YSZ固体电解质的烧结及电性能的影响.结果表明:适量的Al_2O_3能提高YSZ材料的烧结性能,促使其致密化,但过量的Al_2O_3对材料的致密化不利;同时,材料的晶界电导随Al_2O_3含量的增大表现出先增大后减小的变化趋势,这与Al_2O_3对YSZ晶界两方面的不同影响有关,Al_2O_3偏析于晶界一方面能清除晶界上对氧离子电导不利的SiO_2,但另一方面也会降低晶界空间电荷层中的自由氧离子空穴的浓度.

The effects of the alumina doped through the normal co-precipitation on the sintering and conductivity of Yttria-stabilized zirconia were studied. The study shows that proper addition of alumina can accelerate the process of sintering and improve the sintering density of zirconia, but it does harm to the sintering density of YSZ if the content of alumina is too high; the grain-boundary conductivity increases at first and then decreases with increasing content of added alumina. The reason why grain-boundary conductivity changes with the content of alumina is that alumina segregated to the grain boundary has two opposite effects on the grain boundary: at one side it can scavenge silicon dioxide which blocks ionic transport at the grain boundary, at the other side it decreases the free oxygen ion vacancy concentration.