物理学报2017，Vol.66Issue(2)：11-24,14.DOI:10.7498/aps.66.027701
ZnO-Bi2O3系压敏陶瓷缺陷弛豫特性的研究进展
Recent research progress of relaxation performances of defects in ZnO-Bi2O3 varistor ceamics
摘要
Abstract
ZnO varistor ceramics have been widely applied to surge absorption and over-voltage protection in electronic circuit and power system because of their excellent non-ohmic characteristics.Therefore,the reaserch on ZnO varistor ceramic has long been a subject of interest for scholars and industrial circles.At present,the conductance theory of ZnO varistor ceramic has been widely studied and reviewed,and several models such as space charge limited current model,Nordheim-Fowler tunneling current model,and Schottky barrier model have been proposed to describe the electronic transmission process and explain the non-ohmic behavior of ZnO ceramic varistor.However,the relationships of the defect structure and defect relaxation with the electrical property of ZnO varistor ceramic remain unclear,which becomes a challenge to developing new ZnO varistor ceramics.In this paper,comments on defect structures and defect types of ZnO ceramics are given,and the theortical calculation of the intrinsic point defects is discussed.Besides,the characterization technologies of the defect relaxations are introduced.The results show that the dielectric loss spectra are widely used to describe the relaxation of ZnO ceramic varistor,especially the spectra in the low frequency can provide more information about defect relaxation of ZnO ceramic varistor.It is also found that the frequency spectra of admittance in a wide temperature range and the temperature spectra of admittance in a wide frequency range play an equivalent role in characterizing the defect relaxation of ZnO ceramic varistor.The thermally stimulated current is considered to be an effective method to verify the relaxation polarization mechanism of the defects.The deep level transient spectroscopy can characterize the intrinsic and extrinsic defect relaxation processes.Moreover,several theories of relaxation mechanisms such as the Cole-Cole theory,Havriliak-Negami theory and Cole-Davidson theory are proposed to analyze the relaxation phenomena of ZnO ceramic varistors.It is suggested that the electric modulus spectrum combined with Cole-Davidson theory is more effective to characterize the defect relaxations in a wide temperature range.From the electrical degradation results,it is found that the extrinsic defect relaxation at grain boundary interface is closely related to the electrical property of ZnO ceramic varistor.A circuit model is also obtained to establish the correlation between defect relaxation and electrical performance of ZnO ceramic varistor.Therefore,the review on defect relaxations may offer some new ideas to optimize the electrical properties of ZnO ceramic varistors by modifying the defect structures.关键词
ZnO压敏陶瓷/缺陷结构/弛豫机理/电性能Key words
ZnO varistor ceramics/defect structures/relaxation mechanism/electrical properties引用本文复制引用
赵小强,赵学童,许超,李巍巍,任路路,廖瑞金,李建英..ZnO-Bi2O3系压敏陶瓷缺陷弛豫特性的研究进展[J].物理学报,2017,66(2):11-24,14.基金项目
国家自然科学基金青年科学基金(批准号:51407019)、中央高校基本科研业务费(批准号:106112015CDJZR155509)和输变电装备及系统安全与新技术国家重点实验室培育基金(批准号:2007DA10512716302)资助的课题.Project supported the Young Scientists Fund of the National Natural Science Foundation of China (Grant No.51407019),the Fundamental Research Fund for the Central Universities,China (Grant No.106112015CDJZR155509),and the Research Fund from the State Key Laboratory of Power Transmission Equipment & System Security and New Technology,China (Grant No.2007DA10512716302). （批准号:51407019）
