镨系ZnO电阻片非线性特性研究

Investigation of ZnO-Pr_6O_(11)-based Non-linear Varistor non-linear Characteristics

针对镨系ZnO电阻片磨片前后非线性性能的变化,利用X射线衍射仪、扫描电子显微镜及X射线能谱仪对电阻片表面和本体进行分析。结果表明:镨系ZnO电阻片表面层与本体从组分、物相以及微观结构方面均有较大差异,表面层ZnO晶粒尺寸较小,为(2.0～3.1)μm,大小比较均匀,并且在晶界存在约0.7μm的富Pr相,有利于非线性的形成;而本体内的晶粒尺寸较大,为(3.0～4.8)μm,晶界几乎无杂相。磨片后ZnO电阻片表面成分的磨损是导致其非线性性能变差的主要原因。

The electrical properties were measured of ZnO-Pr6O11-based non-linear varistor before and after polished, non-polished surface and polished body were identified respectively by the means of X-ray diffraction（XRD）, energy-disperse X-ray spectroscope（EDX） and scanning electron microscope （SEM）, proper differences in constitution and microstructure between varistor surface and body were found, the ZnO grain size distribution were （2.0-3.1）μm uniformly at surface which is favourable to formation of non-linearity and it were （3.0-4.8）μm inside respectively, additionally, the Pr-phase rich boundaries layer with 0.7μm thickness presented at surface, but almost no Pr-phase boundaries existence inside polished body, the surface wear of polished varistor is the main cause of its non-linearity performance deterioration.