压电陶瓷本征性能的计算与分析

发布时间：2018-06-09 20:17

本文选题：压电陶瓷 + 取向概率密度函数模型　；参考：《天津大学》2014年硕士论文

【摘要】：随着电子产业的不断发展,压电陶瓷的应用也越来越广泛。极化后的压电陶瓷拥有压电性能,而压电性能的优劣影响着材料的可靠度和适用范围。为了计算压电陶瓷极化后的本征性能,本文通过取向概率密度函数(PDFO:Probability Density Function of Orientation)模型,对压电陶瓷内部的电畴取向进行研究。工作及主要成果如下:1、本文通过欧拉角对电畴取向做了规定,使用Reuss假设、电畴转向准则对四方相4mm点群、三方相3m点群和正交相mm2点群进行了研究,得到了这三个单相下的电畴转向分区图和对应完全、不完全极化的PDFO。通过PDFO我们不仅计算得到了压电陶瓷完全、不完全极化后的电畴取向统一程度、剩余极化、介电性能和压电性能的解析解,并纠正了前人通过极图、反极图和取向分布函数(ODF)计算带来的错误结论。2、本文通过引用Landau-Devonshire自由能方程、四方相和三方相的稳定条件和这两相共存的条件,推导了两相共存时四方相和三方相的单晶极化强度。我们引入了"极化强度比值A"来描述两相的关系,并给A进行分区讨论。在各分区内,我们计算得到了两相所占的摩尔百分比,并通过PDFO计算了一系列的本征性能。我们得到的结果是适用于所有的四方三方共存情况的,所有的结果均只与A相关,在计算具体材料时只需将A值代入对应公式即可。3、本文对四方相4mm点群压电陶瓷引入了应变和应力,并通过Eshelby模型描述晶粒之间的关系使之成为一个全局联动模型,最终通过Landau-Devonshire方程导出并以钛酸钡材料为例计算了宏观性能d33的表达式来计算本征部分。
[Abstract]:With the development of electronic industry, piezoelectric ceramics are used more and more widely. The polarization piezoelectric ceramics have piezoelectric properties, and the piezoelectric properties affect the reliability and application range of the materials. In order to calculate the intrinsic properties of piezoelectric ceramics after polarization, the domain orientation in piezoelectric ceramics is studied by using the PDFOO: probability density function of orientation model (PDFOO: probability function of orientation). The work and main results are as follows: 1. In this paper, the domain orientation is defined by Euler angle. Using Reuss hypothesis, the 4mm point group of tetragonal phase, the 3-point group of tripartite phase and the mm2 point group of normal phase are studied by using domain turn criterion. The domain steering zoning diagram and PDFO corresponding to complete and incomplete polarization under these three single phases are obtained. Through PDFO, we not only calculate the analytical solutions of the uniformity of domain orientation, residual polarization, dielectric properties and piezoelectric properties of piezoelectric ceramics after complete and incomplete polarization, but also correct the previous pole diagram. In this paper, by using Landau-Devonshire free energy equation, the stability conditions of tetragonal and tripartite phases and the conditions for the coexistence of these two phases are given. The polarization intensities of tetragonal and rhombohedral phases are derived. We introduce "polarization intensity ratio A" to describe the relationship between two phases, and discuss the partition of A. The mole percentage of two phases is calculated in each partition and a series of intrinsic properties are calculated by PDFO. The results we get are applicable to all quadrilateral coexistence, all of which are related only to A, In this paper, strain and stress are introduced into tetragonal 4mm point group piezoelectric ceramics, and the relation between grains is described by Eshelby model to make it a global linkage model. Finally, the eigenpart is calculated by using Landau-Devonshire equation and taking barium titanate as an example.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM282

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