钛酸钡基温度稳定型介电陶瓷的制备及其性能研究

发布时间：2018-04-30 19:36

  本文选题：钛酸钡 + XRD　； 参考：《桂林理工大学》2015年硕士论文

【摘要】：多层陶瓷电容器(Multilayer ceramic capacitor,MLCC)是重要的电子元器件,已广泛应用于移动通信、测量仪器等电子设备中。随着微电子工业和技术的日新月异,电子元器件的高度集成及微型化迫切需要功能陶瓷材料满足高介电常数、低损耗以及较低温度变化率的要求。目前,大多数的PbTiO3-基陶瓷材料已经应用于电容器领域。然而在生产、制备、使用及废弃处理中,氧化铅的毒性以及在高温下容易挥发等缺点会对环境和人类社会的可持续发展造成极大的破坏。此外,钛酸钡(BaTiO3,BT)被认为是应用最广的一种高介电常数钙钛矿铁电体,但是这类高介质陶瓷材料的介电温度稳定性极差,特别是在相变温度附近介电常数波动很大,极大地限制了其应用。所以,对获得具有应用潜力的宽温度区间稳定型无铅高介电陶瓷体系的探索研究是当下亟需解决的现实问题,同时,研究无铅陶瓷体系的介电性能、弛豫机制以及微观机理是材料科学与凝聚态物理学的交叉点,具有十分重要的理论研究价值。本论文研究依据掺杂改性思想,采用传统两步固相合成法制备了四个不同的陶瓷体系:(1-x)BaTiO3-x Bi(Mg0.75W0.25)O3(BT-BMW)、(1-x)BaTiO3-xBi(Zn0.75W0.25)O3(BT-BZW)、(1-x)BaTi O3-xBi(Mg0.5Zr0.5)O3(BT-BMZ)、(1-x)BaTiO3-xBi(Mg2/3Nb1/3)O3(BT-BMN)无铅钛酸钡基陶瓷体系,并研究了其物相结构、微观显微结构、介电性能以及介电常数温度稳定性。通过系统地对四个不同的陶瓷体系研究表明:BT-BMW、BT-BZW、BT-BMZ和BT-BMN陶瓷体系随着增加掺杂含量,从正常的铁电体逐渐转变为弛豫铁电体;在一定的温度范围内,四个体系均具有高介电常数,较低介电损耗以及较小的介电常数温度变化率。当BT-BMW陶瓷样品组分为0.07≤x≤0.24时,在200~500℃的温度范围内,具有高介电常数(2000~5000)、较低介电损耗以及介电常数的温度变化率(Δε/ε200o C)在±15%以内。当BT-BZW陶瓷样品组分为x=0.04时,在25~125℃的温度范围内,具有高介电常数(~3000)、较低介电损耗(3%)以及介电常数的温度变化率(Δε/ε25o C)在±15%以内,当陶瓷样品组分为x=0.2的(Δε/ε100o C)同样也在±15%内。当BT-BMZ陶瓷样品为x=0.06和0.08,在200~350℃和200~370℃的温度范围内均具有高介电常数(~5000-7000)、较低介电损耗(5%)以及介电常数的温度变化率(Δε/ε27o C)在15%以内,特别对组分为x=0.1,即使测试温度升高到大约400°C,陶瓷样品的Δε/ε200o C同样也在±15%内,该陶瓷样品在25~240°C温度范围内,具有稳定的高介电常数(~6800±15%)、较低介电损耗(≤9%)以及介电常数的温度变化率(Δε/ε100o C)在15%以内。通过掺杂改性,显著改善了四个陶瓷体系的介电常数温度稳定性,同时具有高的介电常数。
[Abstract]:Multilayer ceramic capacitors (MLCC) are important electronic components, which have been widely used in mobile communication, measurement instruments and other electronic devices. With the rapid development of microelectronics industry and technology, the high integration and miniaturization of electronic components urgently need functional ceramics to meet the requirements of high dielectric constant, low loss and low temperature change rate. At present, most of PbTiO 3-based ceramic materials have been used in capacitor field. However, in the production, preparation, use and disposal of waste, the toxicity of lead oxide and the easy volatilization at high temperature will cause great damage to the environment and the sustainable development of human society. In addition, barium titanate BaTiO3B) is considered to be one of the most widely used perovskite ferroelectrics, but the dielectric temperature stability of this kind of high dielectric ceramics is extremely poor, especially in the vicinity of phase transition temperature. Its application is greatly limited. Therefore, it is an urgent problem to explore and study the wide temperature range stable lead-free and high dielectric ceramics system with wide application potential. At the same time, the dielectric properties of lead-free ceramics system are studied. Relaxation mechanism and microscopic mechanism are the intersection of material science and condensed matter physics. In this paper, four different ceramic systems, 1-xBaTiO3-x BiMg0.75W0.75W0.25W0.25O3BT-BMWN-based system, were prepared by conventional two-step solid-state synthesis method, and the phase structure and microstructure of barium titanate were studied. Dielectric properties and temperature stability of dielectric constant. The systematic study of four different ceramic systems shows that the ratio BT-BMW-BT-BZWU BT-BMZ and BT-BMN ceramics gradually change from normal ferroelectrics to relaxor ferroelectrics with the increase of doping content, and the four systems have high dielectric constants in a certain temperature range. Lower dielectric loss and smaller temperature change rate of dielectric constant. When the composition of BT-BMW ceramics is 0.07 鈮，

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