论文总字数：22065字

摘 要

锆钛酸铅（PZT）陶瓷由于其出色的压电性能而广泛用于传感器和微机电设备。但是由于环境问题日益严重，PZT在许多商业应用的使用受到限制。因此，要发现商业化铅的环保良性替代品的压电陶瓷，研究者已经做出大量的努力来寻找具有与铅基系统相当的性能的新型无铅材料。 最近研究集中在具有钙钛矿结构的无铅陶瓷系统上，特别是基于钛酸铋钠Bi_0.5Na_0.5TiO₃（BNT）的组合物。本论文从掺杂改性方面对BNKT-ST基无铅压电陶瓷材料的微观形貌、物相以及应变性能进行探索性研究。

采取传统的固相烧结法制备BNKT-ST陶瓷样品，研究了Nb₂O₅对BNKT-ST陶瓷的微观形貌、物相以及应变性能的影响。结果显示掺杂微量的Nb₂O₅，BNKT-ST陶瓷体系仍然为单一的钙钛矿结构，没有第二相产生，并且限制了晶粒的生长，减小了晶粒的尺寸。使其在电场强度较低的条件下也能获得较大的应变。当Nb的掺杂量为1.5%时，BNKT-ST-1.5Nb陶瓷材料在50 kV/cm电场条件下的双极应变S_max为0.45%，归一化应变d₃₃*（S_max/E_max）为900 pm/V，满足了市场对电器元器件所需性能的要求。

关键词：无铅BNT基陶瓷 应变性能 Nb₂O₅掺杂

Preparation of Nb-doped BNKT-ST Lead-free Piezoelectric Ceramics and Their Strain Properties

Abstract

Lead zirconate titanate (PZT) ceramics are widely used in sensors and MEMS due to their excellent piezoelectric properties. However, because of the increasing environmental problems, the use of PZT in many commercial applications is limited. In order to discover piezoelectric ceramics as a benign alternative to commercial lead, researchers have made considerable efforts to find new lead-free materials that have comparable performance to lead-based systems. Recent studies have focused on lead-free ceramic systems with a perovskite structure, particularly compositions based on sodium barium titanate Bi_0.5Na_0.5TiO₃ (BNT). In this paper, the morphology, phase and strain properties of BNKT-ST lead-free piezoelectric ceramics were explored in terms of doping modification.

The BNKT-ST ceramic samples were prepared by the traditional solid-phase sintering method. The influence of Nb₂O₅ on the micro-morphology, phase and strain properties of BNKT-ST ceramics was studied. The results show that the doped Nb₂O₅, BNKT-ST ceramic system is still a single perovskite structure, there is no second phase, and the growth of grain is limited, reducing the grain size. It can also obtain larger strain under low electric field strength. When the doping amount of Nb is 1.5%, the bipolar strain S_max of the BNKT-ST-1.5Nb ceramic material under the electric field condition of 50 kV/cm is 0.45%, and the normalized strain d₃₃*(S_max/E_max) is 900 pm/V. It met the market requirements for electrical components required performance.

Key Words:Lead-free BNT-based ceramics; Strain performance; Nb₂O₅ doping

目录

摘要 I

Abstract II

第一章 绪论 1

1.1 研究背景及意义 1

1.2 BNT基材料应变性能研究进展 1

1.3 压电陶瓷的应用 2

1.3.1 反铁电储能器 3

1.3.2 相变驱动材料 3

1.4 BNT特性概述 3

1.5 BNT基无铅压电陶瓷掺杂改性机理 4

1.5.1 “软性”掺杂元素掺杂机理 4

1.5.2 “硬性”掺杂元素掺杂机理 4

1.6 研究内容 5

第二章 实验过程与性能表征 6

2.1 实验原料及仪器设备 6

2.2 试验方法与流程 7

2.3 表征方法与仪器设备 9

第三章 实验结果与讨论 10

3.1 不同Nb₂O₅掺杂量对BNKT-ST陶瓷物相的影响 10

3.2 不同Nb₂O₅掺杂量对BNKT-ST陶瓷微观形貌的影响 10

3.3 不同Nb₂O₅掺杂量对BNKT-ST陶瓷P-E回线的影响 11

3.4 不同Nb₂O₅掺杂量对BNKT-ST陶瓷S-E曲线的影响 13

第四章 结论及展望 14

4.1 结论 14

4.2 展望 15

参考文献 16

致谢 20

第一章 绪论

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