Effect of sintering temperature on nonlinearity and surge degradation characteristics of Mn3O4/ Nb2O5/Er2O3‑doped ZnO–V2O5‑based varistors

Nahm, Choon‑W.; Nahm, Choon‑W.

doi:2020.57.1.65

J. Korean Ceram. Soc. > Volume 57(1); 2020 > Article

ORIGINAL ARTICLE

Journal of the Korean Ceramic Society 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

Choon‑W. Nahm

Department of Electrical Engineering, Semiconductor Ceramics Laboratory, Dongeui University, Busan 47340, Republic of Korea

Correspondence

Choon‑W. Nahm ,Email: cwnahm@deu.ac.kr

Received: September 16, 2019; Revised: November 10, 2019 Accepted: November 11, 2019. Published online: January 31, 2020.

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 ΔE _{1 mA/cm²}/E _{1 mA/cm²} = −10.6% , Δ_{α₁∕α₁} = −37.2% and ΔJ_L/J_L = 10.2% after applying a surge current of 200 A.

Key words: Sintering · Nonlinear properties · Surge degradation characteristics · Varistors