Influence of Microstructure and Chemistry on the Electrical Characteristic of ZnO Varistors

  • Tapan K. Gupta

Abstract

The ZnO voltage limiter or varistor1 has an outstanding nonlinear current-voltage (I-V) characteristic and, as such, is used extensively to suppress the transient voltage surges encountered in the lightning and switching surges.2 The advancement in the state-of-the-art of the varistor in recent years3−9 makes it impossible to describe all the elements of this development within the scope of this paper. The objective of this paper is to concentrate on the microstructure and chemistry of the ZnO varistor and their effects on electrical properties. However, in order to appreciate this correlation, it is first necessary to briefly describe the current- voltage (I-V) characteristics of the varistor.

Keywords

Zinc Silicate Bismuth Auger 

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References

  1. 1.
    M. Matsuoka, “Non-ohmic Properties of Zinc Oxide Ceramics,” Jap. J. Appl. Phys., 10, pp. 736–746 (1971).CrossRefGoogle Scholar
  2. 2.
    A. Sweetana, T. K. Gupta, W. G. Carlson, R. Grekila, N. Kunkle, and J. Osterhout, “Gapless Surge Arrestors for Power Systems Applications,” EPRI, EL-3166, Vol. 1, Final Report, September 1983.Google Scholar
  3. 3.
    W. G. Morris, “Electrical Properties of ZnO-Bi2O3 Ceramics,” J. Am. Ceram. Soc., 56, pp. 360–364 (1973).CrossRefGoogle Scholar
  4. 4.
    L. M. Levinson and H. R. Philipp, “The Physics of Metal Oxide Varistors,” J. Appl. Phys., 46, pp. 1332–1341 (1975).CrossRefGoogle Scholar
  5. 5.
    P. R. Emtage, “The Physics of Zinc Oxide Varistors,” J. Appl. Phys., 48, pp. 4372–4384 (1977).CrossRefGoogle Scholar
  6. 6.
    K. Eda, “Conduction Mechanism of Non-ohmic Zinc Oxide Ceramics,” J. Appl. Phys., 49, pp. 2964–2972 (1978).CrossRefGoogle Scholar
  7. 7.
    P. L. Hower and T. K. Gupta, “A Barrier Model for ZnO Varistors,” J. Appl. Phys., 50, pp. 4847–4855 (1979).CrossRefGoogle Scholar
  8. 8.
    G. D. Mahan, L. M. Levinson, and H. R. Philipp, “Theory of Conduction in ZnO Varistors,” J. Appl. Phys., 50, pp. 2799–2812 (1979).CrossRefGoogle Scholar
  9. 9.
    R. Einzinger, “Metal Oxide Varistor Action—A Homojunction Breakdown Mechanism,” App. Surf. Sci., 1 pp. 329–341 (1978).CrossRefGoogle Scholar
  10. 10.
    W. G. Carlson and T. K. Gupta, “Improved Varistor Nonlinearity via Donor Impurity Doping,” J. Appl. Phys., 53, pp. 5746–5753 (1982).CrossRefGoogle Scholar
  11. 11.
    M. Matsuoka, T. Masuyama, and Y. Iida, “Voltage Nonlinearity of Zinc Oxide Ceramics Doped with Alkali Earth Metal Oxide,” Jap. J. Appl. Phys., 8 p. 1275 (1969).CrossRefGoogle Scholar
  12. 12.
    D. R. Clarke, “The Microstructural Location of the Intergranular Metal Oxide Phase in a Zinc Oxide Varistor,” J. Appl. Phys., 49, p. 2407 (1978).CrossRefGoogle Scholar
  13. 13.
    A. T. Santhanam, T. K. Gupta, and W. G. Carlson, “Microstruetural Evaluation of Multicomponent ZnO Ceramics,” J. Appl. Phys., 50 (2), pp. 852–859 (1979).CrossRefGoogle Scholar
  14. 14.
    W. G. Morris, “Physical Properties of the Electrical Barriers in Varistors,” J. Vac. Sci. Technol., 13 (4), p. 926 (1976).CrossRefGoogle Scholar
  15. 15.
    J. Wong, “Nature of Intergranular Phase in Non-ohmic ZnO Ceramics Containing 0.5 Mol.% Bi2O3,” J. Am. Ceram. Soc., 57, pp. 357–359Google Scholar
  16. 16.
    J. Wong, P. Rao, and E. F. Koch, “Nature of an Intergranular Thin-Film Phase in a Highly Non-ohmic Metal Oxide Varistor,” J. Appl. Phys., 46 (4), p. 1827 (1975).CrossRefGoogle Scholar
  17. 17.
    M. Inada, “Crystal Phases of Non-ohmic Zinc Oxide Ceramics,” Jap. J. Appl. Phys., 17 (1), pp. 1–10 (1978).CrossRefGoogle Scholar
  18. 18.
    M. Inada, “Microstrueture of Non-ohmic Zinc Oxide Ceramics,” Jap. J. Appl. Phys., 17 (4), pp. 673–677 (1978).CrossRefGoogle Scholar
  19. 19.
    W. D. Kingery, J. B. Van der Sande, and T. Mitamura, “A Scanning Transmission Electron Microscopy Investigation of Grain Boundary Segregation in a Zn0-Bi2O3 Varistor,” J. Am. Ceram. Soc., 62 (3–4), p. 221 (1979).CrossRefGoogle Scholar
  20. 20.
    J. Wong, “Microstrueture and Phase Transformation in a Highly Non-ohmic Metal Oxide Varistor Ceramic,” J. Appl. Phys., 46 (4), pp. 1653–1659 (1975).CrossRefGoogle Scholar
  21. 21.
    P. Williams, O. L. Krivanek, and G. Thomas, “Microstrueture-Property Relationship of Rare Earth Zinc Oxide Varistors,” J. Appl. Phys., 51 (7), p. 3930 (1980).CrossRefGoogle Scholar
  22. 22.
    M. Inada, Formation of Non-ohmic Zinc Oxide Ceramics,” Jap. J. Appl. Phys., 19 (3), pp. 409–419 (1980).CrossRefGoogle Scholar
  23. 23.
    J. Wong, “Sintering and Varistor Characteristics of Zn0-Bi2O3 Ceramics,” J. Appl. Phys., 51 (8), p. 4453 (1980).CrossRefGoogle Scholar
  24. 24.
    J. Wong and W. G. Morris, “Microstructure and Phases in Non-ohmic ZnO-Bi2O3 Ceramics,” Ceram. Bull., 53, p. 816 (1974).Google Scholar
  25. 25.
    D. R. Clarke, “Grain Boundary Segregation in a Commercial ZnO-Based Varistor,” J. Appl. Phys., 50 (11), p. 6829 (1979).CrossRefGoogle Scholar
  26. 26.
    T. K. Gupta and W. G. Carlson, “A Grain Boundary Defect Model for Instability/Stability of ZnO Varistor,” to be published in J. Mat. Sci.Google Scholar
  27. 27.
    T. K. Gupta and W. G. Carlson, “Barrier Voltage and Its Effect on Stability of ZnO Varistor,” J. Appl. Phys., 53 (11), pp. 7401–7409 (1982).CrossRefGoogle Scholar
  28. 28.
    T. K. Gupta, “60 Hz AC Characteristic of ZnO Varistor Below Breakdown Voltage,” 1984 Conference on Electrical Insl. and Dielectric Phenomena, IEEE Elec. Insl. Soc., October 21–25, pp. 437–447 (1984).Google Scholar
  29. 29.
    G. Heiland and E. Mollwo, in Solid State Physics, Vol. 8, Ed. by F. Seitz and D. Turnbull, Academic Press, New York, p. 215.Google Scholar
  30. 30.
    R. A. Swalin, in Thermodynamics of Solids, Wiley, New York, 1962, Chapter 15.Google Scholar
  31. 31.
    T. Miyoshi, K. Maeda, K. Takahashi, and T. Yamazaki, “Effects of Dopants on Characteristics of ZnO Varistors,” in Advances in Ceramics, Vol. 1, Ed. by L. M. Levinson and D. Hill, Am. Ceram. Soc., 1981, p. 309.Google Scholar

Copyright information

© Plenum Press, New York 1986

Authors and Affiliations

  • Tapan K. Gupta
    • 1
  1. 1.Alcoa LaboratoriesAluminum Company of America Alcoa CenterUSA

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