Voltage Transient Response of a ZnO-Based Multi-Layered Chip Varistor Doped with Alum (AIK(SO_4)_2·12H_2O)

摘要

ZnO-based multi-layered varistor (MLV) added with 0.01 wt/100 alum (AlK(SO_4)_2·12H_2O) as aqueous solution was fabricated by tape-casting and cofiring with Ag-Pd(7:3) inner electrode, with which the effect of alum addition on the varistor characteristics has been studied as a function of firing condition. Throughout the firing temperature range of 950～1100℃, considerable increases in both nonlinear coefficient (α) and the peak current (I_p) have been observed along with lowered voltage clamping ratio (C_R) of～1.5 compared with those in pure MLV. Moreover, the degradation of the leakage current (I_L) under the electrical stress was fairly improved in alum-added MLV fired at 1000～1050℃.