Effect of Heat Treatment on the Nonlinear Exponents in ZnO Varistors

열처리에 따른 ZnO 바리스터의 비직선 계수의 영향

  • 안충선 (경상대학교 무기재료공학과) ;
  • 심영재 (경상대학교 무기재료공학과) ;
  • 조병두 (경상대학교 무기재료공학과)
  • Published : 1992.02.01


Nonlinear exponents and electron trap density variations were observered in ZnO-Bi2O3-MnO2 ternary ZnO varistors as a function of heat treatment temperature. Three kinds of ZnO varistor compositions were selected; i.e. 99.0 ZnO-0.5 Bi2O3-0.5 MnO2, 98.5 ZnO-1.0 Bi2O3-0.5 MnO2, and 98.0 ZnO-1.5 Bi2O3-0.5 MnO2 in mol%. Sintering was done at 1150$^{\circ}C$ for three hours, and heat treatments were done at 500$^{\circ}C$, 700$^{\circ}C$, and 900$^{\circ}C$. When heat treated at 500$^{\circ}C$, nonlinear exponents were increased regardless of the Bi2O3 amount. Increasing heat treatment temperature above 500$^{\circ}C$ resulted in lowering nonlinear exponents. Nonlinear exponents seem to be related to the 0.17 and 0.33 eV electron traps which are possibly of intrinsic origin.



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