改性对钛酸钡基陶瓷储能密度的影响

基于钛酸钡(BaTiO_3)基陶瓷在储能方面的重要应用,介绍了电介质储能的物理基础和影响因素。在此基础上,主要讨论了等价离子掺杂改性、异价离子掺杂改性和包覆改性等对钛酸钡基陶瓷介电性能和储能密度的影响。同时指出优化掺杂改性和包覆改性的组合是提升钛酸钡基陶瓷储能密度的重要途径。     

钛酸钡陶瓷浆料流变性研究

为了获得高固相体积含量、低粘度的钛酸钡(BaTiO3)陶瓷凝胶注模用浆料,研究了粉体粒度、分散剂、球磨时间、pH值对该浆料流变性的影响.结果表明:在相同的固相体积含量下,粉体粒径3μm相比1/μm的BaTiO3浆料具有较小的粘度;用聚丙烯酰胺分散剂,最佳用量相对粉体质量3‰～5‰;球磨8 h浆料的流变性最好;pH值在7～8时浆料的粘度最小.并获得固相体积含量为63%、粘度为690 mPa·s、可易于浇注的BaTiO3陶瓷浆料.     

浆料酸值对钛酸钡电容器介电性能的影响

通过水煮溶液pH值及其电导率、电气强度、介电性能-温度特性、化学组成、陶瓷片表面显微结构等的测试分析．研究了固相反应合成钛酸钡(BaTiO3)粉体中．用氨水调高浆料的pH值对BaTiO3基电子陶瓷电容器的介电性能的影响。结果表明：pH值提高明显改善BaTiO3粉体的性能。在pH=10．3时，合成的BaTiO3中BaO含量降低了92．86％，电气强度提高了29．50％，介电常数峰值提高了15．41％。     

稀土掺杂对BaTiO3陶瓷结构和性能的影响

综合了国内外稀土改性BaTiO3陶瓷的相关研究报导,着重阐述了稀土掺杂对BaTiO3陶瓷电阻率和介电性能的影响规律,并分析了其作用机理。稀土元素作为BaTiO3陶瓷常见的添加剂,可以降低陶瓷电阻率,开发BaTiO3陶瓷半导体领域的应用;可以提高介电常数和改善电容量温度特性,使Ba-TiO3陶瓷满足X7R或X8R特性,可以应用于高压高介电陶瓷电容器中。     

电子陶瓷用钛酸钡粉体制备方法研究进展

介绍了国内外钛酸钡(BaTiO3)粉体的主要制备方法及其发展现状,指出低温燃烧合成法(LCS)法、机械力化学法、水热法方法由于具有许多优良特性而极具发展潜力,并预言钛酸钡的制备方法将会得到迅猛发展。     

混料次序对钛酸钡介电性能的影响

通过改变混料的次序以及采用沉降、水煮损耗、温度特性、电导率和化学分析等测试手段,研究了制备钛酸钡的球磨工艺中混料次序对钛酸钡粉体均匀性及钛酸钡介电性能的影响。研究结果表明:采用不同的混料次序制得的钛酸钡性能差别较大,先钡后钛的方式较优,能减少球磨引起的团聚,极大地改善了固相合成BaTiO3粉体均匀性,提高了钛酸钡的介电性能。     

Al2O3不同掺杂方式对钛酸钡介电性能的影响

采用固相法制备了掺杂1 mol%Al2O3和1mol%Al2O3-2mol%BaO两组钛酸钡陶瓷样品。结果表明:Al2O3两种掺杂方式对钛酸钡的作用效果存在差异,其中Al2O3-2BaO共掺杂的作用效果较强,这与不同掺杂方式所引起的钛酸钡陶瓷的晶格变化差异有关。两种掺杂方式均使钛酸钡陶瓷的εmax减小,居里温度降低,介质损耗降低,同时伴有介温峰展宽,且由于弥散相变的存在其室温介电常数呈增大之势。     

分散剂对钛酸钡介电性能的影响

通过水煮损耗测试、温度特性、电导率和化学分析、瓷片表面显微结构等测试手段,研究了在固相反应制备钛酸钡的工艺中,向BaCO3粉体和TiO2粉体的混合球磨的浆料中加入聚乙烯醇作为分散剂对合成的钛酸钡粉体均匀性的影响。研究结果表明,碱性聚乙烯醇改善合成BaTiO3粉体均匀性的效果最好,介电常数峰值提高了2313、游离BaO含量降低了93.33％。     

无铅压电陶瓷的研究现状与发展趋势

随着人们环保意识的增强,无铅压电陶瓷的研究和开发成为当前压电材料领域研究的热点。本文综述了无铅压电陶瓷研究开发的相关进展,重点介绍了BaTiO3基、Bi1/2Na1/2TiO3基、铋层状结构、(K,Na,Li)NbO3基及钨青铜结构无铅压电陶瓷等体系的研究现状,同时对制备方法也进行了简要的评述,对无铅压电陶瓷的发展趋势作了展望。     

低温烧结新型钛酸钡陶瓷复合材料的介电性能研究

为降低片式多层陶瓷电容器(MLCC)的成本,研究了适宜低温烧结的陶瓷复合材料配方。向钛酸钡中添加不同的无机填料,对浆料进行球磨,然后将研磨好的浆料进行压片,低温烧结,制备出适宜低温烧结的陶瓷复合材料,并对其形貌、强度、介电性能和工艺进行研究。结果表明:添加水玻璃和无机硅胶能使钛酸钡烧结后形成致密的片材强度大、硬度高、不易碎裂;而添加石墨和蒸馏水则不易形成稳定型片材,强度差;添加水玻璃可以使复合材料的介电常数显著增加,水玻璃的最佳添加量为3%。     

K0.5Na0.5NbO3掺杂对BaTi03陶瓷介电性能的影响

采用固相反应法制备了（K0.5Na0.5）Nb03-BaTiO3。体系陶瓷。借助XRD、SEM和阻抗分析仪研究了掺杂（K0.5Na0.5）Nb03（简写为KNN）对陶瓷微结构及介电性能的影响。结果表明,掺杂KNN的陶瓷均呈单一的钙钛矿结构;掺杂KNN能促进陶瓷的烧结和提高陶瓷的致密度。,BaTiO,陶瓷在高温端的电容变化率随KNN量的增加显著减小。陶瓷晶粒尺寸随KNN的增加（KNN掺杂量≤3m01％）逐渐变小。掺杂3mol%6和5m01％KNN的BaTiO3陶瓷满足EIAX7R特性。     

Experimental and numerical studies of dielectric properties of BaTiO/sub 3/-platinum composites at microwave frequencies

The conductor loading method has been used for creating a lossy dielectric material with a desired loss tangent. This method may also be applicable for developing high dielectric constant materials. In this paper, we will present the experimental results of the dielectric properties of BaTiO/sub 3/ and BaTiO/sub 3/ -platinum (BaTiO/sub 3/-Pt) composites. These composite materials were designed to increase the real part of the effective dielectric constant at high frequency. Three different platinum volume fractions were used, 3, 5 and 10%, to make BaTiO/sub 3/-Pt composites, in addition to a pure BaTiO/sub 3/ material. To characterize the BaTiO/sub 3/-Pt composites, microwave frequency measurements were conducted using the waveguide transmission technique. The experimental and numerical results verify that it is possible to increase the dielectric constant using the conductor loading method.     

BaTiO3基抗还原介质陶瓷材料

内电极的贱金属化已成为多层陶瓷电容器发展的一个重要方向。从缺陷化学的观点出发研究BaTiO,基抗还原介质陶瓷,使之能够与镍电极在还原气氛下共烧。综述了BaTiO,基介质陶瓷的抗还原机理、选择掺杂离子的一般原则、制备方法和相关进展。     

钛酸铋钙和稀土复合掺杂对BaTiO3陶瓷微结构和介电性能的影响

研究了稀土及CaBi4Ti4O15（CBT）的复合掺杂对BaTiO3（BT）陶瓷微结构及介电性能的影响。结果表明：单独添加CBT使晶粒细化,促进了陶瓷的烧结致密化,居里温度随着CBT含量的增加（≤0．5mol％）而逐渐移向高温端;当CBT含量由0．3mol％增加到0．5mol％时,BT陶瓷的电容量变化率逐渐减小;当CBT含量超过0．5mol％时,电容量变化率又增大。在BaTiO,CBT（BT—CBT）基础上单独添加1．0mol％La2O3,四方率减小,居里点移向低温端;保持La2O3掺杂量不变,随着CeO2含量的增加,BT—CBT陶瓷的晶胞体积呈现先减小后增大的变化趋势,四方率保持不变;1．0mol％La2O3和0．01mol％CeO2掺杂BT—CBT（0．5m01％）陶瓷在-55℃和125℃的电容变化率分别为-14．78％和-11．44％。完全符合EIAX7R标准,有望用于X7R型多层陶瓷电容器的制备。     

Dielectric and conductive spectra of the composite of barium titanate and LiClO/sub 4/-doped polyethylene oxide

Dielectric and conductive frequency spectra in a 10 mHz-10 GHz range have been measured for a composite consisting of barium titanate (BaTiO/sub 3/) inclusions dispersed in a LiClO/sub 4/-doped polyethylene oxide (Li-PEO) matrix with volume fraction /spl Phi/ = 0-40%. Pure Li-PEO behaves as a dielectric showing a segmental-mode dielectric relaxation at high frequencies (dielectric regime) and transfers to an ionic conductor below 10 MHz (conductive regime). BaTiO/sub 3/ is a ferroelectric having a very large dielectric permittivity and spontaneous polarization. The introduction of BaTiO/sub 3/ into Li-PEO caused a rapid increase in permittivity in the dielectric regime. In the conductive regime, the composite exhibited an additional relaxation at a frequency related to the ratio of DC conductivity of Li-PEO and the permittivity of BaTiO/sub 3/. This relaxation was attributed to accumulation of dissociated Li/sup +/ and ClO4/sup o/ns at the inclusion/matrix interface which resulted in an increase of effective permittivity and a decrease of effective conductivity. Quantitative analyses based on mixing laws for the two-phase spherical dispersion system have shown that the Bruggeman equation accurately predicted the /spl Phi/-dependence of the effective permittivity over the entire frequency range. Regarding the effective conductivity, it predicted values lower than the observed. We attributed this discrepancy to the spontaneous polarization of BaTiO/sub 3/, which induced ion trapping to reduce the DC conductivity of Li-PEO matrix.     

Study of La-doped barium titanate ceramics obtained by laser sintering technique

Journal of Electroceramics - This work studies the influence of laser sintering on the semiconducting properties of La-doped BaTiO3 (BTL) ceramics. The BTL powders were synthesized using a...     

New,Lead Free Materials with a Diffuse Phase Transition: NaNbO 3 -Based Solid Solutions

Last years some lead- free BaTiO 3 -derived solid solution compositions attracted much attention as environmentally benign relaxor materials (Ravez, J., and Simon, A., J. Korean Phys. Society 32, S955 (1998)). However up to now the obtained values of the dielectric permittivity maximum temperature, T m , in the BaTiO 3 -based relaxors were too low for potential applications. The aim of the present paper is studying the dielectric properties of some NaNbO 3 -based solid solutions forming a new family of lead-free materials with diffuse phase transition.