中文摘要：

研究了掺杂Ce2O3和Gd2O3对ZnO—Bi2O3系压敏陶瓷电气性能的影响，发现大尺寸试样的内层电位梯度明显低于表层，即表现出“软心”特征．“软心”导致试样平均电位梯度随着试样几何尺寸的增大而下降．沿轴向晶粒尺寸没有明显的差异．根据沿轴向截取的等厚薄片的电流与温度的关系，发现表层的晶界势垒高度比内层的高．这种晶界势垒高度的非均匀分布可能与添加稀土氧化物后造成的氧元素分布不均匀有关．

英文摘要：

The effects of rare-earth oxide Ce2O3 and Gd2O3 on the electrical properties of ZnOBi2O3 based ceramics were investigated. The non-uniform distribution of voltage gradient along axial direction was found, which leading to the decrease of the average voltage gradient of the sample with the increase of its size. Obvious difference in average grain size along axial direction could not be observed by scanning electron microscope. The distribution of Schottky barrier height was found non-uniform along axial direction by measuring I-T response of thin layers cut from the sample, which is likely to be caused by non-uniform distribution of oxygen element due to the addition of rare-earth oxides.