Effect of Treatment Process on the Structure and Properties of Sr_(0.48)Ba_(0.24)Ca_(0.28)TiO_3-Based Varistor Ceramics

摘要

Sr_(0.48)Ba_(0.24)Ca_(0.28)TiO_3-based varistor ceramics with an excellent capacitor-varistor multifunctional characteristics (V_(1mA) = 11 ～ 49 v.mm~(-1), α = 6.1 ～ 11.3, ε_(r max)=3.5xl0~5, tanδ_(min)= 5%) were prepared using conventional solid method. The effect of oxidation temperature and time on structure and electrical properties were investigated. The results show that with increasing the oxidation temperature from 800℃ to 900℃, the varistor voltage V_(1mA) and non-linearity coefficient α defining varistor characteristics increase linearly, while the dielectric constant ε_r and dielectric loss tanδ decrease linearly. There exists an optimum α value when the specimens were oxidized at 850℃ for 3h. This behavior was explained through various defect reactions of dopants.