Influence of CeO₂-Doping on the Electrical Properties of ZnO-Bi₂O₃-Based Varistor Ceramics

Abstract:

The microstructure and electrical properties of CeO₂-doped ZnO-Bi₂O₃-based varistors were investigated for different amounts of the dopant. The phase composition of CeO₂-doped samples was similar to the undoped samples. Ce mainly segregated at the grain boundaries within the EDS detection limit. The average grain size decreased from 7.3 to 6.7 μm and the breakdown voltage increased from 438 to 501 V/mm when the content of CeO₂ ranged from 0 to 0.2 mol%. The nonlinear coefficient increased from 38 to 51 when the content of CeO₂ increased from 0 to 0.1 mol%., but the further doping caused it to decrease up to 44 at 0.2mol%. The leakage current decreased from 1 to 0.4 μA/cm² when the content of CeO₂ ranged from 0 to 0.1 mol%. Then it increased to 0.7 μA/cm² at 0.2 mol%. The density of interface states, the barrier height and the donor concentration increased when the content of CeO₂ ranged from 0 to 0.1 mol%, but decreased at 0.2 mol%. Hence, when the content ranges from 0 to 0.1 mol%, CeO₂ acts as a donor and can improve the electrical properties.

• Periodical: Key Engineering Materials (Volume 697)
• Pages: 262-266
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.697.262
• Online since: July 2016
• Authors: Zhan Chuan Cao, Liao Ying Zheng, Li Hong Cheng, Tian Tian, Guo Rong Li
• Keywords: CeO₂-Doping, Electrical Properties, ZnO Varistors

References

[1] T. K. Gupta, Application of Zinc-Oxide Varistors, J. Am. Ceram. Soc. 73 (1990) 1817-1840.

[2] D. R. Clarke, Varistor Ceramics, J. Am. Ceram. Soc. 82 (1999) 485-502.

[3] L. Cheng, L. Zheng, G. Li, K. Yuan, Y. Gu, and F. Zhang, The Influence of ZnF2 Doping on the Electrical Properties and Microstructure in Bi2O3-ZnO-Based Varistors, J. Am. Ceram. Soc. 93 (2010) 44-47.

[4] L. Meng, G. Li, L. Zheng, L. Cheng, J. Zeng, H. Huang, and S. Bernik, The Effect of Bi2O3/SiO2 Molar Ratio and Annealing on the dc Degradation of ZnO Varistors, J. Am. Ceram. Soc. 94 (2011) 2300-2303.

DOI: 10.1111/j.1551-2916.2011.04654.x

[5] S. Ma, Z. Xu, R. Chu, J. Hao, M. Liu, L. Cheng, and G. Li, Influence of Cr2O3 on ZnO-Bi2O3-MnO2-based varistor ceramics. Ceramics International, 40 (2014) 10149-10152.

DOI: 10.1016/j.ceramint.2014.02.035

[6] L. Cheng, G. Li, K. Yuan, L. Meng, and L. Zheng, Improvement in nonlinear Properties and Electrical Stability of ZnO Varistors with B2O3 Additives by Nano-Coating Method, J. Am. Ceram. Soc. 95 (2012) 1004-1010.

DOI: 10.1111/j.1551-2916.2011.04900.x

[7] S. Bernik, N. Daneu, Characteristics of ZnO-based varistor ceramics doped with Al2O3, J. Eur. Ceram. Soc. 27 (2007) 3161-3170.

DOI: 10.1016/j.jeurceramsoc.2007.02.176

[8] M. Houabes, R. Metz, Rare earth oxides effects on both the threshold voltage and energy absorption capability of ZnO varistors, 33 (2007) 1191-1197.

DOI: 10.1016/j.ceramint.2006.04.004

[9] S. Bernik, S. Macek, B. Ai, Microstructural and electrical characteristics of Y2O3-doped ZnO-Bi2O3 -based varistor ceramics, J. Eur. Ceram. Soc. 21 (2001) 1875-1878.

DOI: 10.1016/s0955-2219(01)00134-0

[10] M. Lei, S. Li, X. Jiao, J. Li, and M. A Alim, The influence of CeO2 on the microstructure and electrical behaviour of ZnO-Bi2O3 based varistors, J. Phys. D: Appl. Phys. 37 (2004) 804-812.

DOI: 10.1088/0022-3727/37/5/024

[11] M. I. Mendelson, Average grain size in polycrystalline ceramics, J. Am. Ceram. Soc. 52 (1969) 443-446.

[12] K. Mukae, K. Tsuda, I. Nagasawa, Capacitance-vs-voltage characteristics of ZnO varistors, J. Appl. Phys. 50 (1979) 4475-4476.

DOI: 10.1063/1.326411

[13] Q. Yan, Q. Feng, Q. Huang, H. Su, X. Xie, M. Tu, Study on voltage and microstructure of ZnO varistor doped with CeO2, Functional Materials, 38 (2007) 567-569.