论文总字数：18060字

摘 要

压电性是指人们从石英晶体的研究中发现的一种电学现象，即晶体会在被施加各种应力时会发生介电极化，随之晶体两端的表面出现电荷密度相等，符号相反的电荷，且这些电荷的量与所施加的应力大小成正比。具有这些压电效应的晶体可以作为压电材料，这些材料可以将不同形式的机械能与电能之间互相转换，压电材料的应用领域十分广泛，是可以作为换能器、传感器、压电驱动器等等的多功能材料。

其中铁酸铋-钛酸铅二元系固溶体自发极化能力强，居里温度高，介电性能、压电性能、铁电性能好，而且铁电相变温度也很高，这使得铁酸铋-钛酸铅陶瓷材料有能力发展成为性能优异的多功能压电材料。可如果单论铁酸铋-钛酸铅陶瓷材料，其矫顽场强，不容易被极化，陶瓷很难被烧结致密，并且铁酸铋-钛酸铅基材料相较于其他压电陶瓷而言其绝缘性能差强人意，如果不进行其他元素的掺杂改进，单独的铁酸铋-钛酸铅陶瓷材料的压电、介电等性能很难得到应用于表征。本文主要通过分析铁酸铋-钛酸铅陶瓷在掺杂镧元素前后各项性能的变化来研究镧元素对铁酸铋-钛酸铅陶瓷材料结构、性能各方面的影响，并论述了制备铁酸铋-钛酸铅陶瓷工艺的优缺点。

镧的掺杂可以增加铁酸铋-钛酸铅微观电畴的电畴密度，使电畴在外加电场的作用下更容易发生转向，并且在撤去外加电后，镧掺杂的铁酸铋-钛酸铅体系陶瓷的剩余极化强度明显加强。镧的掺杂使铁酸铋-钛酸铅陶瓷本来单一的三方相逐渐向四方相转变，准同型相界向钛酸铅组分靠近。这就使铁酸铋-钛酸铅陶瓷的电阻率提高，绝缘性能提高，介电性能和压电性能增强，矫顽场强强削弱。

关键词：铁酸铋-钛酸铅 压电材料 铁电性 准同型相界 电畴 绝缘性能 镧掺杂

Preparation and characterization of La-doped (1-x) BiFeO₃-xPbTiO₃ piezoelectric ceramics

Abstract

Piezoelectricity is an electrical phenomenon found in the study of Quartz Crystal, that is, the dielectric polarization occurs when the crystal is subjected to various stresses, and then the surface charge density at the two ends of the crystal is equal and the sign is opposite, and the amount of these charges is proportional to the amount of stress applied. Crystals with these piezoelectric effects can be used as piezoelectric materials, which can convert different forms of mechanical and electrical energy to each other. piezoelectric materials have a wide range of applications, can Be used as transducers, sensors, piezoelectric actuators and other multi-functional materials.

Among them, Bismuth ferrate-lead titanate binary solid solution has strong self-polarization ability, high Curie temperature, and high magnetic transition temperature and ferroelectric phase transition temperature, this makes Bismuth ferrate-lead titanate ceramics capable of developing into multifunctional piezoelectric materials with excellent properties. However, Bismuth ferrate-lead titanate ceramics alone have strong coercive field and are not easy to be polarized, and Bismuth ferrate-lead titanate based ceramics have poor insulating properties compared with other piezoelectric ceramics, it is difficult to characterize the piezoelectric and dielectric properties of Bismuth ferrate-lead titanate ceramics without the modification of other elements. In this paper, the effects of Lanthanum on the properties of Bismuth ferrate-lead titanate ceramics were studied by analyzing the properties of Bismuth ferrate-lead titanate ceramics before and after adding lanthanum, the advantages and disadvantages of the preparation process of Bismuth ferrate-lead titanate ceramics are discussed.

The doping of Lanthanum can increase the domain density of BF-PT microdomains, and the domain can easily turn under the effect of Applied Electric Field, the residual polarization strength of lanthanum-doped Bismuth ferrate-lead titanate ceramics is obviously enhanced. The doping of Lanthanum makes the single tetragonal phase of Bismuth ferrate-lead titanate ceramics change to trigonal phase gradually, and the quasi-isotropy to lead titanate. This makes the Bismuth ferrate-lead titanate ceramics have better insulation, dielectric and piezoelectric properties, and the coercive field strength is weakened.

Key words: CBismuth ferrate-lead titanate, piezoelectric material, ferroelectric, quasi-isophase boundary Domain, insulating property, Mixed Lanthanum

目 录

摘 要 I

Abstract II

目 录 i

第一章 绪论 1

1.1 引言 1

1.2 基本概念与原理 1

1.2.1 铁磁性与铁电性 1

1.2.2 铁电体 2

1.2.5 ABO₃型钙钛矿结构化合物 3

1.3 BF-PT材料的结构性能与研究现状 4

1.3.1 BF-PT材料的结构及性能 4

1.3.2 BF-PT材料的研究现状 5

第二章 铁酸铋-钛酸铅系压电陶瓷的制备工艺 6

2.1 固相烧结法 6

第三章 BLF-PT结构与性能分析 9

3.1 致密度的检测 9

3.2 BLF-PT陶瓷的物相结构和表面形貌分析 9

3.3 BLF-PT陶瓷介电压电性能的表征 9

第四章 镧掺杂含量对 0.57BLF-0.43PT 陶瓷性能影响的预测与分析 10

4.1 0.57BLF-0.43PT断面形貌与陶瓷相结构 10

4.2 0.57BLF-0.43PT陶瓷的介电和压电性能 11

第五章 总结与展望 15

参考文献 17

致谢 20

第一章 绪论

1.1 引言

压电器件具有正压电效应和逆压电效应，因此可以将电能与机械能相互转换，从而成为了一种高效的换能器件。不易燃，耐高温，轻质，体积小，与抗电磁干扰，制备工序简易等优良的性能使压电器件成为研究的热点。并且大量应用到军工，医疗，航空航天，民生等广泛的领域中^[1]。

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