Progress in Preparation of ZnO Based Varistor Ceramics

  • O. Milošević
  • D. Vasović
  • D. Poleti
  • Lj. Karanović
  • V. Petrović
  • D. Uskoković


Chemical preparation methods were used to fabricate ZnO-based varistor ceramics having nonlinearity coefficients between 35–45, breakdown fields ranging from 400–1000 kV/m and leakage currents far less than 10−2 A/m2.The processing steps employed include (1) chemical synthesis of powders having a complex initial composition of the form (100−y) ZnO+y (additives) with y selected from the group of soluble salts of Bi, Sb, Co, Mn, Ni and Cr, then (2) calcination of as-prepared powders within the temperature interval from 373 to 1473K and (3) sintering at temperatures from 1373 to 1573K. Two different methods for powder preparation were used: 1) evaporation of ZnO suspensions with additive solutions and 2) coprecipitation of additive solution and afterwards by adding ZnO.

Various analytical methods such as optical and scanning electron microscopy, DTA, TGA, X-ray and EDAX were used in characterizing the powders and the resulting ceramics. Processes of formation of the main phases as well as their influence on resulting non-Ohmic behaviour, was investigated.


Calcination Temperature Spinel Phase Nonlinearity Coefficient Additive Solution Breakdown Field 
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  1. 1.
    M. Matsuoka, “Nonohmic properties of zinc oxide ceramics”, J.J. Appl. Phys., 10(6),(1971)736.CrossRefGoogle Scholar
  2. 2.
    H. R. Philipp, “Grain resistivity and conduction in metal oxide varistors”, in “Tailoring multiphase and composite ceramics”, ed. R. E. Tressler, G. L. Messing, C. G. Pantano and R. E. Newnham, Mat. Sci. Res., 20, Plenum Press, New York and London, 1987, 481.Google Scholar
  3. 3.
    E. Sonder, T. C. Quinby and D. L. Kinser, “ZnO varistors made from powders produced using a urea process”, Am. Ceram. Soc. Bull. 65 (4), (1986), 665.Google Scholar
  4. 4.
    R. G. Dosch, “The effects of processing chemistry on electrical properties of high-field ZnO varistors”, in “Science of ceramics chemical processing”, ed., L. L. Hench and D. R. Ulrich, Wiley & Sons, (1986), 311.Google Scholar
  5. 5.
    S. Hishita, Y. Yao and S. Shirasaki, “Zinc oxide varistors made from powders prepared by amine processing”, J. Am Ceram. Soc. 72 (2), (1989), 338.CrossRefGoogle Scholar
  6. 6.
    R. J. Lauf and W. D. Bond, “Fabrication of high field zinc oxide varistors by sol-gel processing”, Am. Ceram. Soc. Bull., 63 (2), (1984), 278.Google Scholar
  7. 7.
    K. Seitz, E. Ivers - Tiffee, H. Thomann and A. Weiss, “Influence of zinc acetate and nitrate salts on the characteristics of undoped ZnO powders”, Proceeding of the VI World Conf. High. Techn. Ceram., Milano, Italy, June 1986, Elsevier, ed. P. Vincenzíni, 1987.Google Scholar
  8. 8.
    E. Ivers-Tiffee and K. Seitz, “Characterisation of varistor type raw materials prepared by the evaporative decomposition of solutions technique”, Am. Ceram. Soc. Bull., 66 (9), (1987), 1384.Google Scholar
  9. 9.
    F. C. Palilla, “Process for the preparation of homogeneous metal oxide varistors”, U.S. Patent 4,575,440, Mar. 11, 1986.Google Scholar
  10. 10.
    O. Milosevié, D. Vasovic, D. Poleti, Lj. Karanovie, V. Petrovie and D. Uskokovié, “Microstructural and electrical properties of ZnO varistors prepared by coprecipitation and evaporation of suspensions and solutions”, Proceedings of Second Varistor Conference, Schnenectady, USA, Decembar 1988 (in Press).Google Scholar
  11. 11.
    O. Milosevié, P. Kostie, V. Petrovic, Lj. Trontelj and D. Uskokovié, “Crystal phases and electrical properties in nonohmic ZnO ceramics”, Proceeding of the 14th Conference on Silicate Science, Budapest, 6–10 May, 1985.Google Scholar
  12. 12.
    M. Inada, “Crystal phases of nonohmic zinc oxide ceramics”, J. J. Appl. Phys. 17 (1) (1978) 1.Google Scholar
  13. 13.
    V. F. Katkov, A. I. Ivon, V. O. Makarov and I. M. Cernenko, “Formirovaniye struktury oksidno-cinkovoi keramiki” Neorganicheskiye materialy, 24, 8 (1988) 1358.Google Scholar
  14. 14.
    J. Wong, “Barrier voltage measurement in metal oxide varistors”, J. Appl. Phys., 47 (11) (1976) 4971.CrossRefGoogle Scholar
  15. 15.
    O. Milosevie, D. Vasovié, D. Poleti, LJ. Karanovié, V. Petrovie and D. Uskokovié, “Development of crystal phases and nonlinear properties in chemically prepared varistor ceramics”, Paper presented at ECerS ‘89, Maastricht, 18–23 Jun 1989, Holland (to be published in Conference Proceeding).Google Scholar
  16. 16.
    R. Eizinger, “Grain boundary phenomena in ZnO varistors”, in “Grain boundaries in semiconductors”, North-Holland, Amsterdam, 1982, 343.Google Scholar
  17. 17.
    M. V. Vlasova, N. G. Kakazey, O. Milosevie, D. Poleti, D. Vasovié and D. Uskokovié, “Electronic paramagnetic resonance study of the structure of ZnO varistors prepared by various chemical methods”, J. Mater. Sci., 1989 ( Accepted for publication).Google Scholar

Copyright information

© Springer Science+Business Media New York 1989

Authors and Affiliations

  • O. Milošević
    • 1
  • D. Vasović
    • 1
  • D. Poleti
    • 1
  • Lj. Karanović
    • 1
  • V. Petrović
    • 1
  • D. Uskoković
    • 1
  1. 1.Institute of Technical Sciences of the Serbian Academy of Sciences and Arts and Belgrade UniversityYugoslavia

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