Degradation Mechanism of ZnO Ceramic Varistors with the Time on the DC Stress Test

DC 스트레스 시간에 따른 ZnO 세라믹 바리스터의 열화기구

  • 소순진 (원광대학교 대학원 전자재료공학과) ;
  • 김영진 (삼례공업고등학교 전자통신과 교사) ;
  • 소병문 (익산대학 전기과) ;
  • 박춘배 (원광대학교 전기전자 및 정보공학부)
  • Published : 2000.07.01

Abstract

The objective of this paper is to demonstrate degradation phenomena through DC degradation tests and predicts degradation phenomena as a function of time from the tests. The ZnO varistor used in this investigation were fabricated by standard ceramic techniques. Especial, these were sintered in nitrogen atmosphere, at 2 h, for $1300^{\circ}C$. The conditions of DC degradation test were 115$\pm$$2^{\circ}C$for 0, 2, 4, and 8 h, respectively. To demonstrate the degradation phenomena of ZnO varistors, Voltagecurrent analyses were performed before and after the degradation test, and frequency analyses were used with the time of the degradation tests. It was found that the degradation occurred in not grain but grain boundary and the degradation behavior of varistors was unsymmetrically degraded with the direction of tests.