【作者】 李梁玉；

【导师】 伍春燕； 唐新桂；

【作者基本信息】 广东工业大学 ， 物理电子学， 2008， 硕士

【摘要】 钛酸钡系列电子陶瓷是近几十年发展起来的新型现代功能陶瓷。目前已成为现代功能陶瓷中最重要的一类，是电子陶瓷元器件的基础母体原料，被称为电子陶瓷的支柱。自从1942年Wainer和Selomon发现钛酸钡陶瓷具有较好的介电和压电性能以来，钛酸钡作为一种性能优异的铁电材料，近几十年来已发展成为一类新型现代功能陶瓷。但钛酸钡的居里温度在120℃左右，限制了其在室温下的应用。为了改善钛酸钡的室温介电性能，掺杂钛酸钡成为人们首选的研究方向。近年来，Ba(Zr_xTi_1-x)O₃的研究逐渐被人们重视，因为Zr⁴⁺要比Ti⁴⁺稳定的多，同时Ba(Zr_xTi_1-x)O₃的居里温度可以降到室温，具有很好的应用前景。钛酸钡陶瓷的制备方法很多，固相反应法因其工艺简单、产量高、成本低在工业上得到广泛应用，本文分别采用固相法与溶胶-凝胶法制备了锆钛酸钡陶瓷，并对其形貌结构与电学性能进行了研究。采用溶胶凝胶法制备了掺锆钛酸钡(Ba(Zr_0．2Ti_0．8)O₃（BZT20）陶瓷。通过掺锆（Zr含量20 mol％），SEM电镜图象表明制备的BZT20陶瓷粒径约60μm，XRD结果说明掺锆钛酸钡陶瓷是单一的钙钛矿结构，室温下为三方相结构。锆钛酸钡介电温谱没有明显的频率弥散现象，弥散因子γ约为1．64，表明BZT20陶瓷为弥散铁电-顺电相变，且三个相变重合为一个。采用固相反应法制备了掺锆钛酸钡(Ba(Zr_xTi_1-x)O₃，x=0．02，0．04，0．06，0．08，0．10，0．12)无铅陶瓷。考察了样品制备过程中球磨时间、烧结温度、成型压力大小及掺杂多少对锆钛酸钡陶瓷性能的影响。测试结果表明：随着掺锆的增多，XRD衍射峰向低位微移，且（200／002）峰由分裂逐渐融合，说明锆的加入增大了锆钛酸钡陶瓷的晶格常数，且常温下由四方相向三方相转变。锆含量的增加致使BZT陶瓷的居里点降低，弛豫特性增强。铁电性测量显示样品的电滞回线所包含的面积随掺锆的增多在逐渐减小，即样品的极化损耗随之减小。更多还原

【Abstract】 Barium titanate ceramics, which have been developed over the last decades, are a kind of new functional ceramics. Today, they have been one of the most important functional ceramics used as the basic raw materials in the composition of ceramic capacitors. As a high performance ferroelectric materials, barium titanate has been developed into a new kind of functional ceramic since Wainer and Selomon found its good dielectric properties in 1942. But the T_c of Barium titanate is about 120℃which restricts its application in room temperature. Doped barium titanate is the preferred research direction to improve the dielectric properties of barium titanate. In recent years, the research of Ba(Zr_xTi_1-x)O₃ is popular because that the Zr⁴⁺ is much more stable than Ti⁴⁺ and the Tc of Ba(Zr_xTi_1-x)O₃ can be shifted into room temperature.Many methods were used to Prepare barium titanate ceramics, solid-phase reaction of their simple process, high yield and low cost in the industry has been extensively applied. In this paper, barium zirconate titanate ceramics were prepared by solid-phase method and the sol-gel, and their morphology and structure and electrical properties were studied.Barium zirconate titanate Ba(Zr_0.2Ti_0.8)O₃ （BZT20） ceramics have been prepared by a sol-gel process. The phase structure and micrograph of the ceramics was determined by an x-ray diffraction and a scan electron microscope, respectively. The temperature dependence of dielectric permittivity of the ceramics has been investigated. The results show that the grain size of the BZT20 ceramics was about 60 urn, and the XRD patterns indicated a polycrystalline perovskite nature of a tetragonal phase at room temperature. Diffusion constant of BZT20 was about 1.64, which indicates that dispersion ferroelectric-paraelectric phase transition happened.Barium zirconate titanate Ba(Zr_xTi_1-x)O₃,（x=0.02,0.04,0.06,0.08,0.10, 0.12） lead-free ceramics were prepared by a solid-phase reaction. The influence of milling time, sintering temperature, molding pressure on property of BZT ceramics was considered. Test results showed that: with the increase of doped zirconium, XRD peaks shifted to the lower angle slightly, and （200/002） peaks merged slowly. That suggested zirconium doped adding barium zirconate titanate ceramics’ lattice parameters. The Curie temperature of BZT ceramic lowered by zirconium doped. Electrical measurements show that area covered by electrical hysteresis loop gradually decreased with the increase of zirconium doped, which implied the polarization loss decreased accordingly.更多还原