화학공학소재연구정보센터
Korean Journal of Materials Research, Vol.22, No.12, 689-695, December, 2012
Sb/Bi비가 ZnO-Bi2O3-Sb2O3-NiO-Cr2O3 바리스터의 소결과 입계 특성에 미치는 영향
Effect of Sb/Bi Ratio on Sintering and Grain Boundary Properties of ZnO-Bi2O3-Sb2O3-NiO-Cr2O3 Varistor
E-mail:
We have examined the co-doping effects of 1/2 mol% NiO and 1/4 mol% Cr2O3 (Ni:Cr = 1:1) on the reaction, microstructure, and electrical properties, such as the bulk defects and the grain boundary properties, of ZnO-Bi2O3-Sb2O3 (ZBS; Sb/Bi = 0.5, 1.0, and 2.0) varistors. The sintering and electrical properties of Ni,Cr-doped ZBS, ZBS(NiCr) varistors were controlled using the Sb/Bi ratio. Pyrochlore (Zn2Bi3Sb3O14), α-spinel (Zn7Sb2O12), and δ-Bi2O3 were detected for all of compositions. For the sample with Sb/Bi = 1.0, the Pyrochlore was decomposed and promoted densification at lower temperature by Ni rather than by Cr. A homogeneous microstructure was obtained for all of the samples affected by α-spinel. The varistor characteristics were not dramatically improved (non-linear coefficient, α = 5~24), and seemed to form Zni .. (0.17 eV) and Vo .(0.33 eV) as dominant defects. From impedance and modulus spectroscopy, the grain boundaries were found to have been divided into two types, i.e., one is tentatively assigned to ZnO/Bi2O3 (Ni,Cr)/ZnO (0.98 eV) and the other is assigned to a ZnO/ZnO (~1.5 eV) homojunction.
  1. Clarke DR, J. Am. Ceram. Soc., 82, 485 (1999)
  2. Eda K, IEEE Electr. Insul. Mag., 5(6), 28 (1989)
  3. Einzinger R, Annu. Rev. Mater. Sci., 17, 299 (1987)
  4. Greuter F, Blatter G, Semicond. Sci. Technol., 5, 111 (1990)
  5. Gupta TK, J. Am. Ceram. Soc., 73, 1817 (1990)
  6. Inada M, Matsuoka K, Advances in Ceramics; Vol. 7, p. 91, edited by Yan MF, Heuer AH, American Ceramic Society, Columbus, OH, USA. (1984)
  7. Kim J, Kimura T, Yamaguchi T, J. Am. Ceram. Soc., 72, 1390 (1989)
  8. Hong YW, Kim JH, J. Kor. Ceram. Soc., 37, 651 (2000)
  9. Hong YW, Shin HS, Yeo DH, Kim JH, Kim JH, J. KIEEME, 21, 738 (2008)
  10. Karanovic L, Poleti D, Vasovic D, Mater. Lett., 18, 191 (1994)
  11. Mergen A, Lee WE, J. Eur. Ceram. Soc., 17, 1049 (1997)
  12. Brankovic Z , Brankovic G, Poleti D, Varela JA, Ceram. Int., 27, 115 (2001)
  13. Hong YW, Shin HS, Yeo DH, Kim JH, Kim JH, J. KIEEME, 22, 941 (2009)
  14. Hong YW, Shin HS, Yeo DH, Kim JH, J. KIEEME, 23, 942 (2010)
  15. Hong YW, Shin HS, Yeo DH, Kim JH, J. KIEEME, 24, 969 (2011)
  16. West AR, Andres-Verges M, J. Electroceram., 1, 125 (1997)
  17. Abdullah KA, Bui A, Loubiere A, J. Appl. Phys., 69, 4046 (1991)
  18. Hodge IM, Ingram MD, West AR, J. Electroanal. Chem., 74, 125 (1976)
  19. Gerhardt R, J. Phys. Chem. Solids, 55, 1491 (1994)
  20. Hong YW, Kim JH, Ceram. Int., 30, 1307 (2004)
  21. Hong YW, Shin HS, Yeo DH, Kim JH, Kim JH, J. KIEEME, 22, 949 (2009)
  22. Chiou BS, Chung MC, J. Electron. Mater., 20, 885 (1991)
  23. Bueno PR, Varela JA, Longo E, J. Eur. Ceram. Soc., 28, 505 (2008)