中文摘要：

在-180℃—100℃温度范围内研究了ZnO-Bi2O3二元、ZnO-Bi2O3-MnO三元以及商用ZnO压敏陶瓷的I-V特性.研究发现：二元试样电导由散射电导串联构成;三元试样电导由热电子发射电导混联构成;商用试样电导由热电子发射电导和隧道效应电导并联构成.对整个电流范围内的电导拟合表明：通过同一温度下电导分量同电流的关系,可以计算出该部分电导对应的非线性指数.在商用试样中,隧道电流产生的非线性指数为33,与实测值接近;该隧穿分量在小电流区也存在,且在低温下表现地更为明显.

英文摘要：

The I-V characteristics of ZnO-Bi2O3, ZnO-Bi2O3 -MnO systems and commercial ZnO varistor ceramics were measured at temperatures in a wide range of - 180 ℃ 〈 T 〈 100 ℃. It was found that experimental conductance-temperature curves under various currents can be theoretically reproduced by calculating conductance in parallel or series for mechanisms such as scattering mechanism, thermionic emission and tunneling effect. It was found that if the relation between a single-mechanism conductance and temperature obeys the exponential law with an exponent a little less than 1, then this mechanism will give rise to a high nonlinear exponent. The nonlinear exponent due to tunneling effect was 33, which was similar to the measured value of 43 for commercial ZnO varistor ceramics. This tunneling effect is active even at low electric field, especially in low temperature region.