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Article
J. Korean Ceram. Soc. 2020; 57(1): 65-72.
DOI: https://doi.org/10.1007/s43207-019-00009-9
Effect of sintering temperature on nonlinearity and surge degradation characteristics of Mn3O4/Nb2O5/Er2O3‑doped ZnO–V2O5‑based varistors
C.‑W. Nahm
Abstract
This study elucidates the effect of sintering temperature on the nonlinearity and surge degradation characteristics of Mn3O4/Nb2O5/Er2O3–doped ZnO–V2O5-based varistors. With increasing sintering temperature, the average grain size increased from 6.3 to 16.6 μm and the ceramic density decreased from 5.51 to 5.41 g/cm3. The highest nonlinearity (α1 = 45.6) was obtained when the sintering temperature reached 900 °C. The sample sintered at 900 °C exhibited the best clamp characteristics, where the clamp voltage ratio was 1.84–2.44 at a surge current of 1–25 A. By contrast, the sample sintered at 925 °C exhibited the highest electrical stability, where ΔE1 mA/cm2 E1 mA/cm2 = −10.6% , Δ 1∕ 1 = −37.2% and ΔJL/JL = 10.2% after applying a surge current of 200 A.
Keywords
Sintering, Nonlinear properties, Surge degradation characteristics, Varistors
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