Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference (한국전기전자재료학회:학술대회논문집)

The Korean Institute of Electrical and Electronic Material Engineers (한국전기전자재료학회)
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A Microstructural and Electrical Properties of $WO_3$-Doped ZnO Varistors

$WO_3$가 첨가된 ZNO 바리스터의 미세구조적, 전기적 특성

  • 정순철 (동의대학교 전기공학과) ;
  • 박춘현 (동의대학교 전기공학과) ;
  • 남춘우 (동의대학교 전기공학과)
  • Published : 1998.11.01
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Abstract

The influence of $WO_3$ (0.5-4.0mol%) on the microstructural and electrical properties of ZnO varistors was investigated. The major part of a tungsten segregated to the nodal point. SEM, EDAX, and XRD analysis revealed that three phase, such as W-rich phase, Bi-rich phase, and spinel phase, coexist at the nodal point. The average grain size increased in the range of 15.5-29.9pm with increasing $WO_3$ content. This may be probably attributed to liquid phase formed by $WO_3$, $WO_3$ acted as promotion additive of grain growth. As $WO_3$ content increase, the varistor voltage greatly decreased in the range 186.82-35.87V/mm due to the increase of grain growth. The barrier height decreased in the range 1.93-0.42eV with increasing $WO_3$content.

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