Low-voltage Zno Varistors Preparation And Properties

The influences of doping and processing on the character of microstruture and electrical properties were studied by the numbers. Through the studying, we find the suitable composition of Low-voltage ZnO varistor is:0.98ZnO + αPbO+βTiO₂+ γB₂O₃+ x Cr₂O₃+ y Co₂O₃+ z MnO₂+ a Fe₂O₃ + b SiO₂+ c Sb₂O₃ , the parameters as following: α =0.05, β =0.005, γ=0.02, x=0.02, y =0.005, z =0.0025, a =0.002, =0.002 5, c=0.005. The good char-acteristic with V_1mA< 14.5, α > 26 could be got at the proper firing temperature.The influence of nano ZnO and Rare-earths oxide were used as additives on the electrical properties and microstructure of Low-voltage ZnO varistor were systems studied. The results show that the properly adding nano ZnO can improve grain growth, decrease the varisteor voltage remarkably, and at the same time improves the Nonlinear property. The good characteristic with V_1mA<14. 5, α> 26。 Doping Rare-earths oxide can reduce the size of ZnO grain evidently. Improve the varistor voltage and the Nonlinear, decreases the leakage current.In order to get better varistor, we built the model of Gradient Low-voltage ZnO varistor. In this paper, the electronic structure was calculated in the Co, Cr,Mn,Ti,B,Pb, in doping of ZnO, the structure change, band structure density of state and the difference charge density were studied. It was performed by adoping the first-principles calculation of plane wave ultra-soft pseudo-potential technology of based upon the density founction theory.