Effects Sintering Temperature on Electrical Properties of (Pr, Co, Cr, La)-doped ZnO Varistors

(Pr, Co, Cr, La)-doped ZnO 바리스터의 전기적 특성에 미치는 소결온도효과

  • 남춘우 (동의대학교 전기공학과)
  • Published : 2006.12.01


The microstructure, electrical properties, and its stability of (Pr, Co, Cr, La)-doped ZnO varistors were investigated at different sintering temperatures in the range of $1230{\sim}1300^{\circ}C$. As the sintering temperature increased, the sintered density increased from 5.50 to $5.77g/cm^3$, the varistor voltage decreased from 777.9 to 108.0 V/mm, the nonlinear coefficient decreased from 77.0 to 7.1, and the leakage current increased from $0.4{\mu}A\;to\;50.6{\mu}A$. On the other hand, the donor concentration increased from $0.90{\times}10^{18}\;to\;2.59{\times}10^{18}/cm^3$ and the barrier height decreased from 1.89 to 0.69 eV with increasing temperature. The stability of nonlinear electrical properties was obtained from sintering temperature of $1260^{\circ}C$. The varistors sintered at $1260^{\circ}C$ marked the high electrical stability, with $%{\Delta}V_{1mA}=+1.9%,\;%{\Delta}a=10.6%,\;and\;%{\Delta}I_L=+20%$ for DC accelerated aging stress state of $0.95V_{1mA}/150^{\circ}C/24h$.


  1. L. M. Levinson and H. R. Pilipp, 'Zinc oxide varistor-A review', Am. Ceram. Soc. Bull., Vol. 65, No. 4, p. 639, 1986
  2. T. K Gupta, 'Application of zinc dxide varistor', J. Am. Ceram. Soc., Vol. 73, No. 7, p. 1817, 1990
  3. D. R. Clarke, 'Varistors ceramics', J. Amer. Ceram. Soc., Vol. 82, No. 3, p. 485, 1999
  4. K Mukae, K Tsuda, and S. Shiga, 'Development of adanced arresters for GIS with new zinc-oxide elements', EEE Trans. Pow. Deliv., Vol. 3, No. 2, p. 591, 1988
  5. S. Shichimiya, M. Yamaguchi, N. Furuse, M. Kobayashi, and S. Ishibe, 'Development of advanced arresters for GIS with new zinc-oxide elements', IEEE Trans. Pow. Deliv., Vol. 13, No. 2, p. 465, 1998
  6. A. B. Alles, R. Puskas, G. Callahan, and V. L. Burdick, 'Compositional effects on the liquid-phase sintering of praseodymium oxides-based zinc oxides varistors', J. Amer. Ceram. Soc., Vol. 76, No. 8, p. 2098, 1993
  7. Y.-S. Lee, K.-S. Liao, and T.-Y. Tseng, 'Micro structure and crystal phases of praseodymium m zinc oxide varistor ceramics', J. Amer. Ceram. Soc., Vol. 79, p. 2379, 1996
  8. H. H. Hng and K. M. Knowles, 'Microstructure and current-voltage characteristic of praseodymium-doped zinc oxide varistors containing $MnO_2$, $Sb_2O_3$, and $Co_3O_4$, J. Mater. Sci., Vol. 37, No. 6, p. 1143, 2002
  9. C.-W. Nahm, 'The nonlinear properties and stability of $ZnO-Pr_6O_{11}-CoO-Cr_2O_3-Er_2O_3$ ceramic varistors', Mater. Lett., Vol. 47, No. 3, p. 182. 2001
  10. C.-W. Nahm and H.-S. Kim, 'Influence of cooling rate on stability of nonlinear properties of $ZnO-Pr_6O_{11}$-based varistor ceramics', Mater. Lett., Vol. 57, No. 9-10, p. 1544, 2003
  11. C.-W. Nahm, 'Microstructure and electrical properties of $Y_2O_3$ doped $ZnO-Pr_6O_{11}$-based varistor', Mater. Lett., Vol 57, No. 7, p. 1317, 2003
  12. C.-W. Nahm, and B.-C. Shin, 'Effect of sintering time on electrical characteristics and DC accelerated aging behaviors of Zn-Pr-Co-Cr-Dy oxide-based varistors', J. Mater. Sci.: Mater. Electron., Vol. 16, No. 11-12, p. 725, 2005
  13. C.-W. Nahm, 'Influence of Cobalt Oxide addition on nonlinear properties of $ZnO-Pr_6O_{11}$-based varistor ceramics', J. Mater. Sci., Vol. 40, No. 5, p. 1265, 2005
  14. 남춘우, 박종아, 유대훈, 'Zn-Pr-Co-Cr-Er 산화물계 바리스터의 써지 스트레스에 대한 전기적 안정성에 미치는 소결온도의 영향', 전기전자재료학회논문지, 17권, 11호, p. 1167, 2004
  15. 남춘우, 박종아, 유대훈, '소결시간에 따른 $ZnO-Pr_6O_{11}$ 계 바리스터의 전기적, 유전적 특성', 전기전자재료학회논문지, 18권, 6호, p. 543, 2005
  16. J. C. Wurst and J. A. Nelson, 'Lineal intercept technique for measuring grain size in two-phase polycrystalline ceramics', J. Amer. Ceram. Soc., Vol. 55, No. 97-12, p. 109, 1972
  17. K. Mukae, K. Tsuda, and I. Nagasawa, 'Capacitance-vs-voltage characteristics of ZnO Varistors', J. Appl, Phys., Vol. 50, No. 6, p. 4475, 1979
  18. L. Hozer, 'Semiconductor Ceramics; Grain Boundary Effects', Ellis Horwood, p. 22, 1994
  19. J. Fan and R. Freer, 'Deep level transient spectroscopy of zinc oxide varistors doped with aluminum oxide and/or silver oxide', J. Amer. Cearm. Soc., Vol. 77, No. 10, p. 2663, 1994
  20. T. K. Gupta and W. G. Carlson, 'A grain-boundary defect model for instability/ stability of a ZnO varistor', J. Mater. Sci., Vol. 20, p. 3487, 1985