何锦强，蔺家骏，刘文凤，李盛涛*
西安交通大学,电力设备电气绝缘国家重点实验室，西安，710049
关键词：ZnO压敏陶瓷，ZrO2，介电性能
中图分类号：TP242 文献标识码：A
摘要：ZrO2压敏陶瓷由于其优异的非线性V-I特性和大能量吸收能力，广泛应用于电子线路、器件和电力系统的过电压保护中。本文将平均粒径为1μm的ZrO2颗粒掺杂进入ZnO压敏陶瓷，用以提高其抗热震性能。用部分溶液法制备了掺杂ZrO2比例为0.0，0.5，1.0，1.5wt%的多元氧化锌压敏陶瓷，在1215℃保温2h烧结成瓷，研究了ZrO2掺杂对ZnO压敏陶瓷显微结构、电性能和本征点缺陷浓度等方面的影响。EDS和XRD分析表明，ZrO2主要作为第二相存在于晶界中，不与ZnO晶粒发生反应。SEM分析表明，随着ZrO2掺杂量的增加，平均晶粒尺寸逐渐下降，这是由于ZrO2钉扎于晶界中，抑制了液相烧结过程中ZnO晶粒生长。介电谱研究表明ZrO2掺杂进入氧化锌压敏陶瓷后，不会对本征缺陷能级产生影响，但会影响本征缺陷氧空位和锌填隙浓度。通过对-100℃下的介电损耗谱进行拟合分峰，发现氧空位本征缺陷浓度被抑制，而锌填隙本征缺陷浓度增加。由于锌填隙缺陷是亚稳定缺陷，在电场作用下易迁移，锌填隙浓度的增大不利于氧化锌压敏陶瓷的长期稳定性。
The effect of ZrO2 doping on electrical property of ZnO varistor ceramic
HE Jin-qiang, LIN Jia-jun, LIU Wen-feng, LI Sheng-tao
Xi’an Jiaotong University,State Key Laboratory of Electrical Insulation and Power Equipment, Xi’an,710049
Key words：ZnO varistor ceramic, ZrO2, dielectric property
Abstract：ZnO varistor ceramic has been widely applied in electronic circuit and power grid for transient overvoltage protection because of its excellent nonlinear electrical characteristics and energy withstand capability. Herein, ZnO varistor ceramic was doped with ZrO2 to improvethe thermal shock resistance. The multiple-element ZnO ceramic samples with the contents of 0.0, 0.5, 1.0, 1.5wt% ZrO2 were prepared by semi-solution method, and sintered at 1 215oC for 2h. The effect of ZrO2 dopant on microstructure, electrical property, and dielectric property of ZnO varistor was investigated. EDS and XRD results show that ZrO2 is a second phase existing in grain boundaries, and is non-reactive to ZnO. SEM results indicate that the average grain size decreases with increasing ZrO2 doping content, owing to the pinning effect. Dielectric spectrum results reveal that ZrO2 cannot change the energy level of intrinsic point defects, but can influence the concentrations of intrinsic point defects. With peak separation of dielectric loss spectrum, the conduction process and relaxation processes were analyzed, and it was found that the defect concentration of intrinsic oxygen vacancy is decreased, while that of the intrinsic zinc interstitial is enhanced. Intrinsic zinc interstitial with inferior stability is likely to migrate, which is against the long-term stability of ZnO varistor ceramic.