锡锌元素掺杂的钛酸钡陶瓷制备与介电性能研究

发布时间：2018-05-05 07:11

本文选题：电子陶瓷 + 介电性能　；参考：《河南科技大学》2015年硕士论文

【摘要】：BaTi O3是制备多层陶瓷电容器的重要介电材料。不进行掺杂的BaTiO3陶瓷的烧结温度较高、室温相对介电常数较小、介电损耗较大,在相变处存在较强的介电峰。这些不利因素限制了Ba TiO3陶瓷的应用,因而须要通过掺杂改性等方法改善BaTiO3的容温变化率、调控晶粒尺寸分布、降低介电损耗,使它的电学性能符合电子陶瓷行业标准。在本论文的实验中,采用传统的固相反应法烧结工艺制备了单独掺杂Zn O、SnO2、Zn2SnO4及共同掺杂ZnO和SnO2,这四个体系的锡锌元素掺杂的Ba TiO3陶瓷,样品在四种不同的烧结温度和三种不同的保温时间下进行烧结,表征了烧结获得的Ba TiO3陶瓷的烧结特性、介温特性、介频特性、晶格结构和微观形貌等物理性能,从微观形貌演变、晶格参数变化和介电频谱分析等角度讨论了锡锌元素对Ba TiO3陶瓷介电性能产生影响的原因。结果表明,Zn O能够显著促进BaTi O3的烧结,降低烧结温度并减少孔隙数量,掺杂适量的Zn O能够获得具有均匀细晶结构的BaTiO3陶瓷,提高陶瓷的介电常数并减小介电损耗;掺杂SnO2的Ba TiO3陶瓷很难烧结致密,但能够显著地压低介电峰导致介电弥散;在Ba TiO3中掺杂Zn2SnO4可以获得致密的陶瓷,掺杂适量的Zn2SnO4能够提高BaTi O3在室温的介电常数、降低介电损耗并改善材料的容温变化率。掺杂Zn2SnO4比例为2%的Ba TiO3陶瓷的电学性能符合Y5V电子陶瓷行业标准、接近于X7R标准。Zn2SnO4掺杂的BaTi O3陶瓷在宽频区间存在两种弛豫现象,分别是高频区间内由偶极子转向极化引起的Debye型弛豫和低频区间内由氧空位电离引起的弛豫,两种弛豫机制对Zn2SnO4掺杂的Ba TiO3陶瓷在宽温度区间内的介电损耗具有不同的调控作用。
[Abstract]:BaTi O 3 is an important dielectric material for the preparation of multilayer ceramic capacitors. The BaTiO3 ceramics without doping have higher sintering temperature, smaller relative dielectric constant at room temperature, larger dielectric loss and stronger dielectric peak at the phase transition. These disadvantages limit the application of Ba TiO3 ceramics. Therefore, it is necessary to improve the bulk temperature change rate of BaTiO3 by doping modification, adjust the distribution of grain size, reduce dielectric loss and make its electrical properties conform to the standard of electronic ceramics industry. In this paper, the traditional solid-state reaction sintering process was used to fabricate the Ba TiO3 ceramics doped with ZnO and Sno _ 2 and Zn _ (2) O _ (2) O _ (2) O _ (2) O _ (2), respectively, which were doped with Zn / Zn _ (2) O _ (2) and SB _ (2) O _ (2), respectively. The samples were sintered at four different sintering temperatures and three different holding times. The properties of sintering, dielectric temperature, dielectric frequency, lattice structure and microstructure of Ba TiO3 ceramics obtained by sintering were characterized. The influence of tin and zinc on the dielectric properties of Ba TiO3 ceramics was discussed from the point of view of microstructure evolution, lattice parameter change and dielectric spectrum analysis. The results show that Zno can significantly promote the sintering of BaTi O3, decrease the sintering temperature and decrease the number of pores. Doped with proper amount of Zno, the BaTiO3 ceramics with uniform fine crystal structure can be obtained, the dielectric constant of the ceramics can be increased and the dielectric loss can be reduced. It is difficult to sintered SnO2 doped Ba TiO3 ceramics, but it can significantly reduce the dielectric peak and lead to dielectric dispersion. Doped with Zn2SnO4 in Ba TiO3 can obtain dense ceramics, and doped with appropriate amount of Zn2SnO4 can increase the dielectric constant of BaTi O3 at room temperature. Reduce dielectric loss and improve bulk temperature change rate of materials. The electrical properties of Ba TiO3 ceramics doped with 2% Zn2SnO4 are in line with Y5V electronic ceramics industry standard, and there are two kinds of relaxation phenomena in wide band range, which are close to X7R standard. Zn2SnO4 doped BaTi O3 ceramics. They are Debye relaxation induced by dipole polarization in high frequency region and oxygen vacancy ionization in low frequency region. Two relaxation mechanisms have different effects on the dielectric loss of Zn2SnO4 doped Ba TiO3 ceramics in wide temperature range.
【学位授予单位】：河南科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ174.7

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