Abstract
This paper describes a solution-based technique for fabrication of varistor grade composite nanopowders. The method consists of coating major varistor dopants on the surface of the ZnO nanoparticles. As a result, a homogenous mixture of dopants and ZnO nanoparticles will be achieved. TEM results indicated that a composite layer of dopants with the average particle size of 9 nm on the surface of ZnO nanoparticles has been successfully prepared. Sintering of the coated powders was performed in temperatures as low as 850 °C and final specimens with average particle size of 900 nm and density of 98.5% were achieved. In comparison to conventional mixing, varistors prepared from coated nanopowders exhibited superior electrical properties and microstructure homogeneity. The improvement of electrical properties can be attributed to small grain size, homogenous distribution of dopants and elimination of large Bi-Pockets. In addition, the processing route of schottky barrier formation is quite different from what is generally considered as the method of barrier formation in ZnO grain boundaries.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Z. Wang, H. Zhang, L. Zhang, J. Yuan, S. Yan, C. Wang, Nanotechnology 14, 11–15 (2003)
S.C. Pillai, J.M. Kelly, D.E. McCormack, R. Ramesh, J. Mater. Chem. 18, 3926–3932 (2008)
C.P. Fah, J. Wang, Solid State Ion. 132, 107–117 (2000)
K.X. Ya, W. TianDiao, H. Yin, T. MinDe, Mater. Res. Bull. 32, 1165–1171 (1998)
D.R. Clarke, J. Am. Ceram. Soc. 82, 485–502 (1999)
G.E. Pike, in Semiconducting Polycrystalline Ceramics, ed. by M. V. Swain. Materials Science and Technology, vol 11 (VCH, Weinheim, 1994), pp. 731–54
K. Kobayashi, O. Wada, M. Kobayashi, Y. Takada, J. Am. Ceram. Soc. 81, 2071–2076 (1998)
J. Shi, Q. Cao, Y. Wei, Y. Huang, Mat. Sci. Eng. B 99, 344–347 (2003)
M. Singbal, V. Cbbabra, P. Kang, D.O. Shah, Mater. Res. Bull. 32, 239–247 (1997)
P. Duran, F. Capel, J. Tartaj, C. Moure, J. Eur. Ceram. Soc. 22, 67–77 (2002)
S. Chu, T. Yan, S. Chen, Ceram. Int. 26, 733–737 (2000)
C. i Hu, M.N. Rahaman, J. Am. Ceram. Soc. 75, 2066–2070 (1992)
D. Hreniak, P. Psuja, W. Strek, J. Ho lsa, J. Non-cryst. Solids 354, 445–450 (2008)
R.G. Dosch, B.A. Tuttle, R.A. Brooks, J. Mater. Res. 1, 90–99 (1986)
Y. Li, G. Li, Q. Yin, Mat. Sci. Eng. B 130, 264–268 (2006)
Q. Wang, Y. Qin, G.J. Xu, L. Chen, Y. Li, L. Duan, Z.X. Li, Y.L. Li, P. Cui, Ceram. Int. 34, 1697–1701 (2008)
A. Lorenz, J. Ott, M. Harrer, E.A. Preissner, A.H. Whitehead, M. Schreiber, J. Eur. Ceram. Soc. 21, 1887–1891 (2001)
P. Sulcova, M. Trojan, Dyes Pigments 36, 287–293 (1998)
M. Afzal, P.K. Butt, H. Ahrnad, J. Therm. Anal. Calorim. 37, 1015–1023 (1991)
M.B. Maecka, R. Gajerski, S. Labus, J. Therm. Anal. Calorim. 72, 135–144 (2003)
T. Wanjun, C. Donghua, Chem. Pap. 61, 329–332 (2007)
W. Onreabroy, N. Sirikulrat, A.P. Brown, C. Hammond, S.J. Milne, Solid State Ion. 177, 411–420 (2006)
J.P. Gambino, W.D. Kingery, G.E. Pike, L.M. Levinson, H.R. Philipp, J. Am. Ceram. Soc. 72, 642–645 (1989)
F. Yuan, H. Ryu, J. Am. Ceram. Soc. 87, 736–738 (2004)
D. Wei, R. Dave, R. Pfeffer, J. Nano. Res. 4, 21–41 (2002)
A. Banerjee, T.R. Ramamohan, M.J. Patni, Mater. Res. Bull. 36, 1259–1267 (2001)
J.L. Baptista, P.Q. Mantas, J. Electroceram. 4, 215–224 (2000)
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Shojaee, S.A., Maleki Shahraki, M., Faghihi Sani, M.A. et al. Microstructural and electrical properties of varistors prepared from coated ZnO nanopowders. J Mater Sci: Mater Electron 21, 571–577 (2010). https://doi.org/10.1007/s10854-009-9959-3
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10854-009-9959-3