The Influence of AL2O3 Dopants on the Electrical Properties of ZnO-Bi2O3 Based Varistor at Different Sintering Temperature

ZnO Varistor samples with different amount of additive (0.7%Bi2O3, 1%Sb2O3,0.5%Cr2O3, 0.5%MnO2, 0.8%CoO) as well as 0.1 % mol of AL2O3 were prepared by a conventional route and sintered in air for 2h at a different sintering temperature (1000,1100, 1200)ᴼC at a heating rate of (5ᴼC. min-1). The microstructure and Electrical properties of sintered samples were investigated by using X-ray diffraction (XRD), Energy Dispersive Spectroscopy (EDX), Scanning Electron Microscopy (SEM) as well as Electrical measurements. The best electrical characteristic were obtained in the sample sintered in air at (1000ᴼC) for 2h,which exhibited the nonlinear coefficient of (46),breakdown voltage of (2090V) , and leakage current of (0.04mA)