The effect of firing temperature on the electrical properties and the microstructure of ZnO varistors doped with CuO

M.M.Saadeldin; M.M.Younis; M.M. Ahmed; M.Y. Helali

Volume : V, Issue : X, October - 2015

The effect of firing temperature on the electrical properties and the microstructure of ZnO varistors doped with CuO

M. M. Saadeldin, M. M. Younis, M. M. Ahmed, M. Y. Helali

Abstract :

 Mixtures of ZnO doped with CuO were prepared by solid state reaction from the calcined oxides. Additives present in grain boundaries between ZnO grains.XRD showed that no binary compound was formed and there are increase in dislocation density with additives. The conductivity and the dielectric constant are highly dependent on the microstructure of conducting grains surrounded by this insulating oxide barrier. Dielectric constant and conductivity are decreases where mixes fired at 1200°C. The amounts of additives affect the coefficient of non–linearity and eakdown voltage. Microstructure had been studied with SEM and AFM that revealed the presence of inter–granular phase. Increasing firing temperature increase the grain size of ZnO which doped with CuO.