KIEE International Transactions on Electrophysics and Applications

The Korean Institute of Electrical Engineers (대한전기학회)
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The Effect of Microstructure Nonuniformity on the Electrical Characteristics of ZnO Varistors with $Al_2$O$_3$ doping

  • Han, Se-Won (KERI (Korea Electrotechnology Research Institute)) ;
  • Cho, Han-Goo (KERI (Korea Electrotechnology Research Institute))
  • Published : 2003.08.01
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Abstract

The influence of microstructure nonuniformity on the electrical characteristics of ZnO varistors was analyzed with the added amount of $Al_2$O$_3$ dopants. $Al_2$O$_3$ doping can effectively inhibit grain growth. When $Al_2$O$_3$ content is in the range between 0-0.1 %, the average grain size and the standard deviation decrease quickly and the grain growth is strongly inhibited. Therefore, it is possible to increase the microstructure uniformity by accurate addition of $Al_2$O$_3$ to the ZnO varistor. The breakdown voltage increases with the decrease of standard deviation. The greater the uniformity of the Zno varistor means the higher the global breakdown voltage. The $Al_2$O$_3$ dopants having about 0-0.023 wt% content can effectively improve the voltage ratio, and the voltage ratio reaches a minimum value of 2.32 at an $Al_2$O$_3$ content of 0.005 wt%.

Keywords

References

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