The DC accelerated aging behavior of the Co–Dy–Nb doped Zn–V–Mn-based varistors was investigated at different sintering temperatures of 850–950 °C. The microstructure of the samples consisted of ZnO grain as the main phase, and Zn3(VO4)2, ZnV2O4, and DyVO4 as the secondary phases, which acts as liquid-phase sintering aids. The nonlinear coefficient exhibited the highest value, reaching 57 for a sintering temperature of 950 °C and the lowest value, reaching 8 for a sintering temperature of 850 °C. Concerning stability, the varistors sintered at lower temperature than 925 °C exhibited a relatively low stability with %ΔE1 mA more than 10%. However, the varistors sintered at higher temperature than 925 °C exhibited a high stability. The varistors sintered at 925 °C exhibited the most stable accelerated aging characteristics, with %ΔE1 mA = −3.9%, %Δα = −40.3%, %ΔεAPP′ = −1.0%, and %Δtanδ = +19.1% for DC accelerated aging stress of 0.85 E1 mA/85 °C/24 h.
Sinter Temperature Schottky Barrier Leakage Current Density Nonlinear Coefficient Sintered Density
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