研究了CuO掺杂对WO_3压敏电阻微结构和电学行为的影响,样品采用传统的陶瓷工艺制备.微结构通过扫描电子显微镜(SEM)观察,相结构和成分借助于X射线衍射(XRD)和能谱(EDS)进行分析.结果表明,微量的CuO掺杂能够促进WO_3陶瓷的致密化和晶粒生长.根据I-V特性测量结果,0.2%(摩尔分数)CuO掺杂的WO_3陶瓷具有线性伏安特性和极小的电阻率.CuO含量的继续增加使样品的非线性电学行为和电阻率又获得恢复,这是因为偏析于晶界处的CuO与两侧的晶粒形成了n-p-n型的双肖特基势垒.
The effects of CuO addition on the microstructure and electrical properties of the WO_3 varistors were considered in this paper. The samples were prepared using a conventional mixed oxide route. The grain size and microstructure were investigated by scanning electron microscopy (SEM).The phases and chemical composition were analyzed by X-ray diffraction (XRD) and energy dispersive spectroscopy(EDS).The results indicate that minor addition of CuO promotes the densification and grain growth of WO_3 ceramics. From the I-V measurements, the samples present linear current-voltage characteristic and the resistivity is quite low when doped with 0.2mol% CuO. A further increase in CuO content can recover the nonlinear electrical properties, this is because the excess CuO precipitates in the grain boundary and formed n-p-n type double Schottky barriers.
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