Effects of Doped Pr_6O_(11) on the Properties of ZnO-Bi_2O_3 System Varistors

The ZnO-Bi2O3 system varistors were modified by doping with rare-earth oxide Pr6O11 and their electrical properties and microstructure were investigated. The results of experiment indicate that adding a small scale of Pr6O11 would increase the nonlinear coefficient greatly and decrease the leakage current with no change in threshold voltage. When the Pr6O11 content reaches to 7wt%, the threshold voltage increases by about 60%, whereas the leakage current and nonlinear coefficient are unchangable. The SEM and XRD analyses testify that Pr6O11 makes the microstructure of the materials more uniform and compact.