摘要
压电陶瓷作为一种可以实现机械能和电能之间相互转换的功能陶瓷材料,广泛应用于传感器、制动器、超声换能器、医学超声成像及发动机燃油喷射系统等领域。在压电陶瓷中,元素掺杂可以有效调控陶瓷的电学性能,伴随掺杂而产生的缺陷偶极子对压电陶瓷性能有着显著而独特的影响。因此研究缺陷偶极子对压电陶瓷性能的调控机理,有助于理解压电陶瓷诸多物理现象的内在成因,譬如老化、疲劳等。通过元素掺杂引入的氧空位会导致钙钛矿结构的压电陶瓷产生缺陷偶极子,而缺陷偶极子与自发极化之间的耦合效应会影响陶瓷的铁电响应行为,从而使得压电陶瓷出现束腰电滞回线和偏移电滞回线等特征。另外由于陶瓷中氧空位的扩散速率很低,使得缺陷偶极子极化方向趋于稳定,进而抑制极化旋转和限制畴壁运动,有助于提高压电陶瓷的机械品质因数。尽管有大量研究通过缺陷偶极子调控压电陶瓷的宏观性能使其能够满足不同的应用需求,然而由于压电陶瓷为多晶材料,其内部晶粒取向各异且存在复杂的铁电畴结构,压电陶瓷中缺陷偶极子在形成过程中的微观机理与其具体形态以及缺陷偶极子对压电陶瓷性能的具体作用机理仍有待深入研究。此外,压电陶瓷在高驱动场下的高功率特性对机电设备的实际设计具有重要意义,因此缺陷偶极子对压电陶瓷高功率特性的影响也值得关注。本文从氧空位诱导缺陷偶极子的形成及其表征手段、缺陷偶极子对铅基压电陶瓷电滞回线的影响和不同受主掺杂对铅基压电陶瓷机械品质因数的影响出发,论述了缺陷偶极子与压电陶瓷自发极化耦合效应引发的偏移和束腰奇异电滞回线特征,揭示了缺陷偶极子主要通过抑制极化旋转和限制畴壁运动提高机械品质因数的机理。然而关于缺陷偶极子的形态、与非四方相间的耦合关系以及缺陷偶极子对压电陶瓷高功率特性的影响等问题仍需进一步的研究。
Piezoelectric ceramics,which can realize the conversion between mechanical energy and electrical energy,are widely used in sensors,brakes,ultrasonic transducers,medical ultrasonic imaging and engine fuel injection systems.For piezoelectric ceramics,element dopingc an effectively control the electrical properties of ceramics.Defect dipoles which are caused by doping have significant and unique influence on the performance of piezoelectric ceramics.Therefore,studying the regulation mechanism of defect dipoles on the properties of piezoelectric ceramics is helpful to understand the origin of many physical phenomena,such as aging and fatigue.The oxygen vacancy introduced by element doping can lead to the formation of defect dipoles in perovskite piezoelectric ceramics,and the coupling effect between the defect dipoles and spontaneous polarization can affect the ferroelectric response behavior of the ceramics,resulting in the pinched polarization hysteresis loop and asymmetric polarization hysteresis loop.In addition,the low diffusion rate of oxygen vacancies in ceramics stabilizes the polarization direction of defect dipoles,which restrains the polarization rotation and restricts the motion of domain walls,thus improving the mechanical quality factor.Numerous studies have adjusted the macroscopic properties of piezoelectric ceramics through defect dipoles to make it meet different application requirements.However,due to piezoelectric ceramics are polycrystalline materials with different grain orientations and complex ferroelectric domain structures.Therefore,the microscopic mechanism during the formation process of the defect dipoles and its specific shape in the piezoelectric ceramics and the specific mechanism of the effect of the defect dipoles on the properties of piezoelectric ceramics need to be further studied.In addition,the high-power characteristics of piezoelectric ceramics under high driving fields are of great help to the actual design of electromechanical devices.Therefore,the impact of defect dipoles on the high-power characteristics of piezoelectric ceramics should also be paid attention to.The research progress in the field of the mechanism of defect dipoles regulating the properties of lead-based piezoelectric ceramics is summarized in this paper.The formation and characterization of defect dipoles caused by oxygen vacancies,the influence of defect dipoles on the hysteresis loops of piezoelectric ceramics,and the influence of doping of different low valence elements on the mechanical quality factor(Qm)of lead-based piezoelectric ceramics are discussed.It can be summarized that the coupling between the defect dipoles and the spontaneous polarization of piezoelectric ceramics leads to pinched polarization hysteresis loops and asymmetric polarization hysteresis loops.In addition,the defect dipoles can improve the mechanical quality factor of materials by suppressing polarization rotation and limiting domain wall motion.However,further research is needed to study the shape and distribution of the defect dipoles,the coupling between the defect dipoles and the non-tetragonal phase,and its effect on the high power characteristics of the piezoelectric ceramics.
作者
唐明响
陈良
祁核
孙胜东
刘辉
陈骏
TANG Mingxiang;CHEN Liang;QI He;SUN Shengdong;LIU Hui;CHEN Jun(Department of Physical and Chemistry,University of Science and Technology Beijing,Beijing 100083,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2022年第2期62-67,共6页
Materials Reports
基金
中央高校基本科研业务费(06500162)。
关键词
铅基压电陶瓷
氧空位
缺陷偶极子
电滞回线
机械品质因数
lead-based piezoelectric ceramics
oxygen vacancies
defect dipoles
hysteresis loop
mechanical quality factor
