Y_2O_3-MgO共稳定ZrO_2的相含量及形貌研究

Research on the Phase,Microstructure of ZrO_2-Y_2O_3-MgO System

用湿化学法制备的Y2O3-MgO共稳定ZrO2固体电解质,分别在1550℃,1600℃,1630℃下烧结,获得了室温下单斜相和四方相含量不同的烧结样品。结果表明:随着氧化钇含量的增加,单斜相含量降低,四方相含量增加。烧结温度对相含量的影响较小。(MgO,Y2O3)-PSZ材料断口组织致密,结构均匀且晶粒大小一致,当Y2O3含量较高(≥2.5mol%)时,材料中出现过烧现象。采用Y2O3和MgO复合稳定剂共同稳定ZrO2,能有效地降低材料的烧结温度,且弯曲强度得到明显提高。从当前实验结果来看,在8.0 mol%MgO-ZrO2的基础上,加入2.0 mol%Y2O3在1600℃烧结,得到的材料弯曲强度性能最佳。

The zirconia-yttria-magnesia （ZrO2-Y2O3-MgO） powder was prepared by wet chemical method. The samples which had different amount of monoclinic and tetragonal phase at room temperature were obtained after sintering at 1550℃ , 1600℃ , 1630℃. The results indicate that the content of monoclinic zirconia had decreased while that of the tetragonal zireonia increased according to the addition of yttria and the sintering temperature had little influence on the phase transformation. The microstructure of the fracture surface of （MgO, Y2O3 ）-PSZ was homogeneous and dense, while the grain size was uniform, The material was overroasting when the component of Y2 O3 was too high （ ≥ 2.5 mol% ）. Moreover, the bending strength of the material could be greatly improved by doping Y2O3 and MgO together while the sintering temperature needed was lower. As far as this experiment was concerned, the （MgO, Y2O3 ）-PSZ with 2.0 mol% Y2O3 had the best bending strength after sintered at 1600℃ .