Effects of Eu_2O_3 doping on microstructural and electronic properties of ZnO Bi_2O_3-based varistor ceramics prepared by high-energy ball milling

ZnO Bi2O3-based varistor ceramics doped with Eu2O3in a range from 0 to 0.4%were obtained by high-energy ball milling and fired at 900 1 000°C for 2 h.XRD and SEM were applied to determine the phases and microstructure of the varistor ceramics.A DC parameter instrument was applied to investigate the electronic properties and V–I characteristics.The XRD analysis of Eu2O3-doped ZnO Bi2O3-based varistor ceramics shows that the ZnO,Eu-containing Bi-rich,Zn7Sb2O12-type spinel and Zn2Bi3Sb3O14-type which is the pyrochlore phase are present.With increasing Eu2O3content,the average size of ZnO grain firstly decreases and then increases.The grain boundary defect model was particularly used to explain the excellent nonlinearity of ZnO Bi2O3-based varistor ceramics with the addition of 0.1%Eu2O3and sintered at 950°C.

ZnO-Bi2O3-based varistor ceramics doped with EU2O3 in a range from 0 to 0.4% were obtained by high-energy ball milling and fired at 900-1000 ℃ for 2 h. XRD and SEM were applied to determine the phases and microstructure of the varistor ceramics. A DC parameter instrument was applied to investigate the electronic properties and V-I characteristics. The XRD analysis of Eu2O3-doped ZnO-Bi2O3-based varistor ceramics shows that the ZnO, Eu-containing Bi-rich, Zn7Sb2O12-type spinel and Zn2Bi3Sb3O14-type which is the pyrochlore phase are present. With increasing Eu2O3 content, the average size of ZnO grain firstly decreases and then increases. The grain boundary defect model was particularly used to explain the excellent nonlinearity of ZnO-Bi2O3-based varistor ceramics with the addition of0.1% Eu2O3 and sintered at 950 ℃.