论文总字数：25338字

摘 要

近年来，随着人们越来越多地意识到含铅材料对人体的危害，铅基反铁电材料正在逐渐被无铅反铁电材料所取代。铌酸钾钠反铁电陶瓷由于其较高的居里温度，以及较低的理论密度，在储能和制动方面有着较大的应用可行性。铌酸钾钠陶瓷是由反铁电的铌酸钠与铁电的铌酸钾所组成的二元固溶体陶瓷，是一种有一定研究前景的反铁电材料。在该材料的组分系统中，Na与K的比值可以进行多种改变，并且这种改变并不会改变其钙钛矿的晶体结构。

本论文从传统的固相烧结方法入手，制备了组分为K_0.005Na_0.995NbO₃的铌酸钾钠反铁电陶瓷。通过改变该确定组分下制备陶瓷的一次球磨时间、预烧温度、烧结温度以及保温时间，来研究所制备的原料的颗粒大小、晶体结构、微观形貌，以及所制备陶瓷的致密性、物相结构、晶粒大小和电性能等性质。

研究发现，在1340℃下保温4小时所制备的KNN陶瓷有着较高的致密性，但其颗粒大小的均匀性并不是很高，且有一定的较大间隙存在。通过绘制该陶瓷P-E、S-E曲线，发现该陶瓷有着较大的P_r与E_c值，且需在较大的电场强度下才能显示出应变，且应变值较低。

关键词：反铁电材料 铌酸钾钠基陶瓷 固相烧结 电滞回线

Abstract

In recent years, as people increasingly awaring of the harmful effects of leaded materials on the human body，lead-based antiferroelectric materials are gradually being replaced by lead-free antiferroelectric materials. Niobate anti-ferroelectric ceramics，due to its high Curie temperature and lower theoretical density, have played an essential role in the applications of energy-storage materials and braking materials. Potassium niobate ceramic is one of the composed binary solid solution ceramics of antiferroelectric sodium niobate and ferroelectric potassium niobate. The ratio of Na and K can be a variety of changes, and this does not change its perovskite structure.

In this paper, the technology to prepare the sodium potassium niobate anti-ferroelectric ceramic is traditional solid-phase sintering method. The particle size, crystal structure, microstructure and properties of the prepared materials and the determined components, phase structure, grain size and electrical properties were studied by changing the primary milling time, the calcination temperature, the sintering temperature and the soaking time of the ceramic.

It was found that the sodium potassium niobate anti-ferroelectric ceramic ceramics prepared at 1340 ℃ for 4 hours had a high density, but the uniformity of the particle size was not very high. There also were some large gaps in its structure. By plotting the ceramic P-E and S-E curves, it is found that the ceramic has a large Pr and Ec value, and it needs to exhibit a strain at a large electric field intensity and the strain is small.

Key Words: Antiferroelectric materials; Potassium niobate sodium - based ceramics; Solid - phase sintering; Hysteresis loops

目 录

摘 要 Ⅰ

Abstract Ⅱ

第一章 绪论 1

1.1反铁电材料概述 1

1.1.1 铁电材料定义 1

1.1.2 反铁电材料理论基础 2

1.2 铌酸钾钠陶瓷究进展 2

1.2.1 铌酸钾钠陶瓷研究综述 2

1.2.2 铌酸钾钠陶的性能及应用 3

1.3 铌酸钾钠陶瓷的制备方法 5

1.4 研究目的与内容 6

第二章 实验过程 7

2.1 实验原料与所用设备 7

2.2 实验设计与实验过程 8

2.2.1 实验方法 8

2.2.2 实验流程 9

2.3 实验测试与表征 10

2.3.1 陶瓷样品收缩率 10

2.3.2 陶瓷样品致密度 11

2.3.3 陶瓷样品微观形貌 11

2.3.4 陶瓷样品物相结构 11

2.3.5 陶瓷样品电滞回线 11

第三章 结果分析与讨论 13

3.1 不同球磨时间对混合原料的粒度影响 13

3.2 不同煅烧温度对铌酸钾钠固溶物晶体结构的影响 13

3.3 二次球磨对煅烧样品晶粒粒度的影响 14

3.4 不同烧结温度和保温时间对K_0.005Na_0.995NbO₃陶瓷性能的影响 15

3.4.1 对陶瓷收缩率与致密度的影响 15

3.4.2 对陶瓷晶体结构的影响 16

3.4.3 对陶瓷微观形貌的影响 17

3.4.4 对陶瓷电性能的影响 18

第四章 结论与展望 21

4.1 结论 21

4.2 展望 21

参考文献 22

致 谢 25

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