Bi4Ti3O12 modified low voltage ZnO-based varistors: microstructure, electrical properties and aging characteristics

The effects of Bi4Ti3O12 addition on the microstructure, electrical properties and aging characteristics of ZnO-based varistors were investigated. The addition of Bi4Ti3O12 can reduce the formation of Zn2TiO4 spinel phase and promote the growth of ZnO grain. Bi4Ti3O12 doped ZnO-based varistors sintered at 1,130 A degrees C possessed excellent performance of I (L) = 2.9 mu A, E (1mA) = 29.7 V/mm, alpha = 30.2, and good surge absorption capability with %a-E-3 (1mA) = -3.5 % for 500 A 8/20 mu s impulse current. In addition, the varistors exhibited the most stable accelerated aging characteristics with %a-E-3 (1mA) = -0.3 % for DC accelerated aging stress of 125 A degrees C/7 h. These results revealed that Bi4Ti3O12 addition is highly beneficial to attain enhanced varistor properties of ZnO ceramics.