Sintering Temperature Dependence of Varistor Properties and Aging Behavior in ZnO-Pr_6O_(11)-CoO-Cr_2O_3-Al_2O_3-Y_2O_3 Ceramics

摘要

The sintering temperature dependence of varistor properties and aging behavior in ZnO-Pr_6O_(11)-CoO-Cr_2O_3-Al_2O_3-Y_2O_3 ceramics were investigated at the sintering temperature of 1280°-1350℃. The sintered density was almost unaffected by the sintering temperature. The breakdown field decreased in the range of 4610-1513 V/cm with the increase of sintering temperature. The nonh'near coefficient decreased slightly from 47 to 44, whereas it is close to approximately 45 for all the samples. The highest stability of electrical and dielectric characteristics against DC-accelerated aging stress with sintering temperature was obtained for the sintering temperature of 1320 ℃, at which the %ΔE_B=+0.3%, %Δ_α = 7.3%, %Δε'_(APP) =-5.6%, and %Δtan δ = +88.9%, respectively, for the stress state of 0.95 E_B/150℃/24 h.