Effect of Quenching on Dielectric Properties of ZnO Varistor Ceramics

  • Kangning WuEmail author
  • Yuwei Huang
  • Jianying Li
Conference paper
Part of the Lecture Notes in Electrical Engineering book series (LNEE, volume 598)


ZnO varistor ceramics quenched under different temperatures were investigated from the aspect of dielectric responses. Nonlinear coefficient α and electrical breakdown field E1mA were significantly different when quenching temperature was around 600 ℃. From dielectric responses under low temperatures, it was found that densities of both zinc interstitials and oxygen vacancies increased at first and then decreased when quenching temperature decreased from 1200 ℃ to room temperature. Noticeably, the quenching temperature where zinc interstitial density reaches its peak was lower than that for oxygen vacancy, suggesting that oxygen vacancies were more sensitive to the ambient temperature. For dielectric responses under high temperatures, DC conductance was so intense that relaxations with long relaxation times were covered and not easily characterized via traditional dielectric spectra. Therefore, an improved dielectric spectroscopy free of DC conductance was employed. In samples quenched below 600 ℃, two distinct relaxations originated from interfacial polarization and interface states were found. The interface polarization only appears when quenching temperature is below 600 ℃, accompanied by notably improved resistance in small-current region. With quenching temperature increased, a new low frequency dielectric relaxation appeared, whose origin still needs further investigation.


ZnO Varistor Dielectric Schottky barrier 



This work is supported by the National Key Research and Development Program of China (No. 2018YFB0905802), the State Key Program of National Basic Research (973 Program) of China (No. 2015CB251003).


  1. 1.
    Stucki, F., Greuter, F.: Key role of oxygen at zinc oxide varistor grain boundaries. Appl. Phys. Lett. 57, 446–448 (1990)CrossRefGoogle Scholar
  2. 2.
    Cordaro, J.F., Shim, Y., May, J.E.: Bulk electron traps in zinc oxide varistors. J. Appl. Phys. 60, 4186–4190 (1986)CrossRefGoogle Scholar
  3. 3.
    Cheng, P., Li, S., Zhang, L., Li, J.: Characterization of intrinsic donor defects in ZnO ceramics by dielectric spectroscopy. Appl. Phys. Lett. 93, 988 (2008)Google Scholar
  4. 4.
    Ohbuchi, Y., Kawahara, T., Okamoto, Y., Morimoto, J.: Characterization of interface states in degraded ZnO varistors. Jpn. J. Appl. Phys. 41, 190–196 (2002)CrossRefGoogle Scholar
  5. 5.
    Eda, K., Matsuoka, M.: Thermally stimulated current in nonohmic ZnO ceramics. Jpn. J. Appl. Phys. 16, 195–196 (1977)CrossRefGoogle Scholar
  6. 6.
    Zhao, X., Li, J., Li, H., Li, S.: Intrinsic and extrinsic defect relaxation behavior of ZnO ceramics. J. Appl. Phys. 111, 124106 (2012)CrossRefGoogle Scholar
  7. 7.
    Yang, X., Hu, J., He, J.: Effect of interfacial charge relaxation on conducting behavior of ZnO varistors under time varying electric fields. Appl. Phys. Lett. 110, 485–646 (2017)Google Scholar
  8. 8.
    Wu, K., Huang, Y., Xin, L., Li, J., Li, S., Liu, W.: Understanding of DC degradation of ZnO varistor ceramics from the aspect of high-temperature relaxation. In: 12th International Conference on the Properties and Applications of Dielectric Materials, Xi’an, China, May 2018Google Scholar
  9. 9.
    Olsson, E., Dunlop, G.L., Osterlund, R.: Development of interfacial microstructure during cooling of a ZnO varistor material. J. Appl. Phys. 66, 5072–5077 (1989)CrossRefGoogle Scholar
  10. 10.
    Wu, K., Huang, Y., Li, J., Li, S.: Space charge polarization modulated instability of low frequency permittivity in CaCu3Ti4O12 ceramics. Appl. Phys. Lett. 111, 042902 (2017)CrossRefGoogle Scholar
  11. 11.
    Wu, K., Huang, Y., Hou, L., Zhuang, T., Li, J., Li, S.: Effects of dc bias on dielectric relaxations in CaCu3Ti4O12 ceramics. J. Mater. Sci. -Mater. Electron. 1–7 (2017)Google Scholar
  12. 12.
    Wu, K., Huang, Y., Xing, Z., Zhang, C., Hu, X., Guo, P., Zhang, J., Li, J.: Understanding the validity of impedance and modulus spectroscopy on exploring electrical heterogeneity in dielectric ceramics. J. Appl. Phys. 125, 084103 (2019)CrossRefGoogle Scholar

Copyright information

© Springer Nature Switzerland AG 2020

Authors and Affiliations

  1. 1.State Key Laboratory of Electrical Insulation and Power EquipmentXi’an Jiaotong UniversityXi’anChina

Personalised recommendations