摘要本论文采用传统固相法制备 Sm2O3 掺杂非化学计量(Ba0。75Sr0。25)Ti1+δO3 体系电容 器介质陶瓷，利用 SEM 分析及 LCR 测试系统，研究了不同主晶相、Sm2O3 掺杂量、 成型压力和烧结工艺（保温时间）对体系微观结构和介电性能的影响。83343

研究结果表明：随着δ取值的增大，(Ba0。75Sr0。25)Ti1+δO3 陶瓷的居里温度基本不变， 居里峰越来越平缓，稳定性提高，室温介电常数降低；Sm2O3 掺杂(Ba0。75Sr0。25)Ti1。006O3 陶瓷并未有效改善其微观结构。同时，Sm2O3 固溶于(Ba0。75Sr0。25T1。006)O3 陶瓷晶体中， 占据钙钛矿晶格 A 位引起晶格畸变，降低其室温介电常数，且随着 Sm2O3 掺杂量的 增大，试样的居里温度向低温方向移动；保温 2h 下烧结的试样介电常数峰值最高， 保温 1h 和 4h 的试样介温稳定性较高；此外，发现成型压力可以改善钛酸锶钡的介电 性能。

毕业论文关键词：BST 陶瓷；Sm2O3；微观结构；介电性能

Abstract In this graduation project,the Sm2O3-doped nonstoichiometric Ba0。75Sr0。25Ti1+δO3 system capacitor dielectric ceramics were prepared by the conventional solid state method。 In addition,we use SEM analysis system and LCR test system to study the effects of different main crystalline phase, Sm2O3 doped volume, compression pressure and sintering holding time on the microstructure and dielectric properties of the system。

The research results show that: with the increase of the value of δ, the Curie temperature of the BST ceramic is basically the same, the Curie peak is more and more smooth, the room temperature dielectric constant is reduced。Sm2O3-doped Sm2O3 doped Ba0。75Sr0。25Ti1+δO3 ceramics did not improve the microstructure effectively。Also,Sm2O3 can significantly increaces the system’s room temperature restivity, and reduce the system’s room temperature dielectric constant by occupying the A site in perovskite structure, causing the unit celldistortion。 With the increase of Sm2O3 doping amount, the Curie temperature of Ba0。75Sr0。25Ti1。006O3 system ceramics shifts to lower temperature range。The peak value of dielectric constant of sintered specimen under thermal insulation 2h was the highest, and the temperature stability of 1H and 4H was higher。 In addition, it was found that the pressure could improve the dielectric properties of barium strontium titanate。

Keywords: (Ba0。75Sr0。25)Ti1+δO3 ceramics; Sm2O3;microstructure ,dielectric properties

目 录

第一章 绪论 1

1。1 研究背景 1

1。2 钛酸锶钡陶瓷简介 1

1。2。1 晶体结构 1

1。2。2 钛酸锶钡的电学性能 2

1。3 掺杂改性对钛酸锶钡陶瓷介电性能的影响 3

1。4 氧化钐的相关介绍 4

1。4。1 氧化钐的结构 4

1。4。2 氧化钐的性质 5

1。4。3 氧化钐的应用 5

1。5 钛酸锶钡陶瓷的制备方法 5

1。5。1 固相法 5

1。5。2 液相法 6

1。5。2。1 水热合成法 6

1。5。2。2 沉淀法 6

1。5。3 气相法 7

第二章 试样制备及实验方法 8