Research On High Voltage Gradient ZnO Varistor Formula Based On The Solid Phase Synthesis Process

ZnO varistor has very good volt-ampere nonlinear curve and surge currentabsorption ability, so it is more and more widely used in many applications. Thisdissertation introduces the development of ZnO varistor. Furthermore, the basicstructure, electrical performance, conductive mechanism and transformation mechanismof ZnO varistor were also studied. In this dissertation, the solid sate reaction method hasbeen used to improve the uniformity of the additive distributed in the ZnO varistor andreduce the porosity. To further improve the electrical performance and surge absorptionability of ZnO varistor, effects of the adding amount of additives on electricalperformance of ZnO varistor have been investigated using factor test method.Furthermore, this dissertation mainly studied the influences of the additives (Ni, Si, Sband Sn) with different dosages on breakdown voltage, surge absorption capacity,clamping voltage ratio, nonlinear coefficient and leakage current. An optimized formulahas been obtained. After repeated trials of this formula, it is found that this formula cansignificantly improve the electrical performance and surge absorption ability of ZnOvaristor. In addition, effects of sintering temperatures on the flow ability of ZnO varistorhave been analyzed after three groups contrast experiments, obtaining the optimalsintering curve.