Influence of Bi-Co-O synthetic multi-phase on electrical properties of the ZnO-Bi2O3-MnO2-SiO2 varistors

The electrical properties of ZnO-Bi2O3-MnO2-SiO2-based (ZBMS) varistors as a function of synthetic multi-phase (SMP) produced by pre-sintering the mixture of 16Bi2O3·Co2O3 (Bi-Co-O) were investigated. The Bi-Co-O SMP can modify the transportation of the absorbed oxygen in grain boundary layers and then improves electrical properties. Samples doped with 8 wt% SMP shows the excellent electrical properties: the nonlinear coefficient α increased up to 45.97 corresponding to the high barrier height φb of 1.23 eV, the leakage current JL decreased to 0.5 μA.