Effect of the sintering temperature on the electrical properties of Y–Al‐doped ZnO varistors

Abstract

Abstract To investigate the relationship between the electrical properties of Y–Al doped ZnO varistors and sintering temperature, in this study, we measured the voltage–current characteristics and electrical performance parameters of samples sintered at 1100∘C–1300∘C. Scanning electron microscopy observations revealed that as the sintering temperature increased, the grain size grew significantly, leading to a reduction in voltage gradient. Through C--V characteristic testing, X‐ray diffraction and energy dispersive X‐ray spectroscopy analysis, it was found that the increase in sintering temperature promoted the formation of interface negative charge and defect reactions by Y3+, increasing Ni and Nd; Al3+ tends to aggregate in the grain area, further increasing Nd; the volatilization of Bi3+ gradually increases, causing a decrease in Ni; the Φb first increases and then decreases with the changes in Ni and Nd, resulting in a U‐shaped variation characteristic of the nonlinear coefficient and leakage current density. At a sintering temperature of 1200∘C, the performance of ZnO varistors is optimal.

Keywords

• electrical properties
• sintering temperature
• Y–Al doping
• ZnO varistor