Effects of Spinel on the Formation Process of Nonohmic ZnO Ceramics

비오옴 ZnO 세라믹스의 형성과정에서 스피넬의 영향

  • 김경남 (강원대학교 재료공학과) ;
  • 한상목 (강원대학교 재료공학과)
  • Published : 1992.02.01

Abstract

Sintering behavior, distribution of dopant oxides and electrical properties in the ZnO-Bi2O3-CoO-Sb2O3 and ZnO-Bi2O3-CoO-Sb2O3-Cr2O3 systems were studied. The linear shrinkage of ZnO varistors from 850 to 950$^{\circ}C$ was related to the decomposition reaction (py\longrightarrowsp+Bi2O3) of the pyrochlore phase. In the distribution of the dopant oxides (CoO, Sb2O3, Cr2O3), Co distribute uniformly throughout the sample, the distribution of Sb coincided with small particles (spinel phase, Zn7Sb2O12), and Cr distributed very consistently with Sb. The increase in breakdown voltage, due to the addition of Cr2O3, was not only attributed to the decrease in the ZnO grain size but also to the solution of Cr2O3 in the spinel phase. The leakage current (80% V60 ${\mu}\textrm{A}$) was increased by the addition of Cr2O3.

Keywords

References

  1. Amreican Ceramic Society v.3 Ceramic Transcations(Advances in Varistor Technology) L.M. Levinson
  2. J. Appl. Phys v.49 no.5 Conduction Mechanism of Non-ohmic Zinc Oxide Ceramics K. Eda
  3. J. Kor. Ceram Soc. v.28 no.2 Microstructure and Phase Transition of ZnO Varistor Ceramics K.N. Kim;S.M. Han
  4. J. Am. Ceram Soc. v.72 no.4 Effect of Heat Treatments on the Wetting Behavior of Bismuth-Rich Intergranular Phases in ZnO:Bi:Co Varistors J.P. Gambino;W.D. Kingery;G.E. Pike;L.M. Levinson;H.R. Philipp
  5. J. Appl. Phys. v.50 no.4 Theory of Conduction in ZnO Varistors G.D. Mahan;L.M. Levinson;H.R. Philipp
  6. Ceram. Bull. v.53 no.11 Microstructure and Phases in Nonohmic ZnO-Bi₂O₃Ceramics J. Woung;W.G. Morris
  7. J. Am. Ceram. Soc. v.72 no.8 Sintering of Zinc Oxide Doped with Antimony Oxide and Bismuth Oxide J.H. Kim;T. Kimura;T. Yamaguchi
  8. J. Am. Ceram. Soc. v.67 no.3 Hindrance of Grain Growth in Al₂O₃by ZrO₂Inclusions F.F. Lange;M.M. Hirlinger
  9. Jpn. J. Appl. Phys. v.10 no.6 Non-ohmic Properties of ZnO Ceramics M. Matsuoka
  10. J. Appl. Phys. v.46 no.4 Microstructure and Phase Transformation in Highly Nonhmic Metal Oxide Varistor Ceramics J. Wong
  11. Jpn. J Appl. Phys. v.30 no.8 The Effects of Valence States of Manganese on Electrical Properties of ZnO Varistors Y.C. Chen;C.Y. Chen;H.Z. Chen;Y.F. We.;L. Wu
  12. J. Appl. Phys. v.17 no.1 Crystal Phases of Nonohmic ZnO Ceramics M. Inada
  13. J. Mat. Sci. v.25 Characterization of Spinel Particles in Zinc Oxide Varistors T. Asokan;R. Freer
  14. J. Appl Phys. v.66 no.9 The Effect of Bl₂O₃Content on the Microstructure and Electriacal Properties of ZnO Varistor Materials E. Olsson;G.L. Dumlop
  15. J Appl. Phys. v.51 no.8 Sintering and Varistor Characteristics of ZnO-Bi₂O₃Ceramics J. Wong
  16. Advances in Ceramics American Ceramic Society Effect of Dopant Valence State on the Microstructure of ZnO Varistors J.M. Driear;J.P. Guertin;T.O. Sokoly;L.B. Hackney
  17. J. Mat. Sci. v.23 Effect of SiO₂and Cr₂O₃on the Formation Process of ZnO Varistors H. Kanai;M. Imai