A Study on the Degradation Mechanism of ZnO Ceramic Varistor Manufactured by Ambient Sintering-Process

분위기 소결공정에 의해 제조된 ZnO 세라믹 바리스터의 열화기구 연구

  • 소순진 (원광대학교 대학원 전자재료공학과) ;
  • 김영진 (삼례공업고등학교 전자통신과) ;
  • 박춘배 (원광대학교 전기전자 및 정보공학부)
  • Published : 2000.04.01

Abstract

The relationship between the DC degradation characteristics of the ZnO varistor and the ambient sintering-process is investigated in this study. ZnO varistors made o matsuoka’s composition were fabricated by standard ceramic techniques. The ambient sintering-process is performed at the extraordinary electrical-furnace which is equipped with the vacuum system. Gases used in sintering process were oxygen nitrogen argon and air. Using XRD and SEM the phase and microstructure of samples were analyzed respectively. The conditions of DC degradation tests were conducted at 115$\pm$2$^{\circ}C$ for 13 h. Current-voltage analysis is used to determine nonlinear coefficients($\alpha$). Frequency analysis are performed to understand electrical properties as DC degradation test. From above analysis it is found that the ZnO varistor sintered in oxygen atmosphere showed superior properties at the DC degradation test and degradation phenomenon of ZnO varistor is caused by the change of electrical properties in grain boundary. These results are in accordance with Gupta’s degradation model.

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