钛酸钡粉体制备方法研究进展

钛酸钡因其具有优越的介电性能而被广泛应用于多层陶瓷电容器、热敏电阻、光电器件等电子元件。本文综述了钛酸钡粉体制备的各种方法 ,认为液相法制备的粉体因具有纯度高、成分均匀、粒径小等特点而成为制备粉体主要方法 ,其中溶胶 -凝胶自燃合成法工艺简单、粉体自净化、易于规模化生产 ,水热合成法所得粉体不团聚、粒度较均匀 ,是两种极具发展前景的制粉方法     

钛酸钡粉体的水热法合成

本文简要介绍了水热法合成的钛酸钡粉体的优异特性，合成过程的主要影响因素及其关键。该粉体特别适用于制造ＭＬＣ。     

纳米钛酸钡粉体材料的制备方法

本发明公开了一种纳米钛酸钡粉体材料的制备方法。该方法是以氯化钡BaCl2、钛酸H2TiO3为主要原料，经强氧化剂催化，加氨水调整pH值为12左右进行过滤，获得BaTiO3溶液，置入高温高压反应釜内，处理温度为300～400℃，压力为15～22MPa．冷却后，进行真空干燥，获得纳米级的钛酸钡粉末材料。本发明提供的方法成本低廉，生产效率高，成品率高，杂质少，从而更适应产业化发展的要求。     

钛酸钡粉体制备过程中钛和钡的化学分析方法研究

用络合滴定法定量分析了钛酸钡制备过程中原料TiCl4,Ti(OC4H9)4,中间体TiO(NO3)2和产物BaTiO3中钛含量。研究表明:EDTA返滴定法测定溶液中Ti含量时,H2O2存在可以使分析的相对误差由9.21%减小到0.15%,向含10mg钛的溶液中加1mLH2O2(1+1),分析精度最高,低于或高于此值都使分析误差增大;调整溶液至pH5～5.5范围内,能使终点有敏锐的颜色突变。该方法已用于钛酸钡纳米粉生产过程的控制分析,测得自制BaTiO3粉体中钡、钛摩尔比BaO∶TiO2=1 002∶1。     

钛酸钡包覆镍粉的制备与性能表征

本文将尝试制作钛酸钡包覆镍复合粉体.用来解决多层陶瓷电容器(MLCC)中的镍电极和介质材料在烧结过程中会出现的收缩率不同,以及镍电极容易氧化的问题.以乙酸钡和钛酸丁酯为原料,应用溶胶-凝胶法成功的制作了钛酸钡包覆镍复合粉体.具体分析了加水量和醋酸对溶胶-凝胶黏度的影响.包裹后的镍粉的烧结性能和抗氧化性能有了明显的提高.     

TiCl4共沉淀法合成超细钛酸钡粉体

本研究采用TiCl4和BaCl2配制混合溶液,加入自制混合表面活性剂,以NH4HCO3和NH3·H2O作沉淀剂合成钛酸钡前驱体,再经过1020℃煅烧制成超细钛酸钡粉体.研究了物料配比、TiCl4浓度、表面活性剂用量、加料方式、反应温度、煅烧温度等因素对钛酸钡理化指标的影响,合成.     

超细钴粉制备的研究进展

本文综述了国内外制备超细钴粉的一些方法,并对我国这方面的研究和开发工作提出了建议。     

纳米氧化铈粉体的制备技术研究进展

介绍了近年来国内外纳米氧化铈制备技术的研究情况,重点介绍了液相法的多种制备方法和特点,并对纳米氧化铈的制备技术和发展趋势进行了展望。     

片状金属粉末的制备及研究进展

片状金属粉末具有的特殊二维平面结构,使其显示出优于其它形状粉末的性能,如良好的附着力、显著的屏蔽效应及优良的导电性能等,因此在颜料、涂料和导电浆料等领域具有重要的应用前景。综述了几种常见片状金属粉末的制备、应用及研究进展,并对其未来的研究进行了展望。     

高强镁合金的制备及研究进展综述

镁合金具有极其优异的性能,被誉为\"21世纪绿色工程材料\".镁合金可分为变形镁合金、铸造镁合金、常规镁合金和稀土镁合金,本文详细介绍了镁合金分类及其特性,同时综述了高强镁合金的常见制备工艺及应用现状,着重介绍粉末冶金法、快速凝固法、机械合金化和挤压成型技术,展望了高强镁合金在轻量化工业的发展方向,旨在为我国镁合金行业发展...     

Synthesis and Sintering of Nanocrystalline Barium Titanate Powder under Nonisothermal Conditions. Part V. Nonisothermal Sintering of Barium Titanate Powders of Different Dispersion

A comparative study has been made of the processes involved in the consolidation of nanosized barium titanate powders by nonisothermal sintering at a linear heating rate, by rate-controlled sintering, and high-pressure sintering (up to 5 GPa). The use of linear heating and high-pressure has been found to be ineffective for obtaining nonporous ceramics (residual porosity of about 2%) and for miniziming grain growth. The application of external pressure does not prevent coalescent grain growth controlled by surface diffusion. When rate-controlled sintering is employed a densification/grain growth optimum can be attained with a relative density of 99.9% of the theoretical value and a grain size of about 100 nm.     

钛酸锶钡（BST）材料的制备方法、理论及应用的研究进展

铁电材料,由于在电子器件行业具有巨大的应用前景,因而受到科学上和技术上的广泛关注,钛酸锶钡（BST）材料的最新理论进展和制备方法的发现,为人们提供了新的应用机会。本文对钛酸锶钡材料的理论研究进展、制备方法和新的应用作了详细阐述。     

Synthesis and Sintering of Nanocrystalline Barium Titanate Powder under Non-Isothermal Conditions. Part 6. Structure,Grain Boundaries,and Dielectric Properties of Barium Titanate Obtained by Various Sintering Methods

The grain boundary structure of barium titanate obtained by controlled-rate sintering and high-pressure sintering (HPS), and the dependence of dielectric properties on grain size and consolidation method were studied. It was shown that sintering without the application of pressure leads to a diffusion-controlled formation of equilibrium grain boundaries with minimal impedance factor, which minimally decrease the dielectric constant of the ceramics. HPS results in the formation of non-equilibrium grain boundaries which have a large free volume, and which substantially decrease the dielectric constant. The Curie-Weiss constant was analyzed from the viewpoint of a matrix structural model, and a «brick-wall» model.     

Dopant Behaviours of Sm_2O_3 on Microstructure and Properties of Barium Zirconium Titanate Ceramics

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Effects of Dysprosium Oxide Doping on Microstructure and Properties of Barium Titanate Ceramic

With the development of mixed integrated cir-cuits , mini mization of high voltage ceramic capacitorcomponents usedin high voltage outletsis required .Inthe past ,the breakdown voltage was raised mainly byincreasingthethickness of capacitors .Butthe most …     

钛酸钡超细粉体的共沉淀法制备及陶瓷的性能研究

以TiCl4和BaCl2·2H2O为原料,NH4HCO3和NH3·H2O为沉淀剂,采用化学共沉淀方法制备钛酸钡粉体。研究了钛酸钡粉体的合成条件对产物纯度、颗粒粒径、颗粒形貌及瓷体介电特性等影响。使用X射线衍射仪、激光粒度仪、扫描电子显微镜等进行测试分析,找出了较佳的制备条件。结果表明:采用适宜的原料配比Ba/Ti=1:1、反应温度20℃、NH4HCO3/Ba2+值为1.2、煅烧温度950℃等条件,可制得颗粒质量中位径D50为270nm、粒度分布均匀的四方相钛酸钡粉体。瓷体的烧结温度为1260℃,烧结时间为2h时,瓷体的密度最大,常温介电常数达到1763。     

Preparation and Characterization on Nano-Sized Barium Titanate Powder Doped with Lanthanum by Sol-Gel Process

The nano-sized BaTiO3:La3 powders were prepared by sol-gel process using butyl phthalate, barium acetate and lanthanum oxide as raw material, and these samples were tested by means of TG-DTA, XRD and SEM. The results indicate that with the annealing temperature and the doped concentration rising, the powders' particle sizes will increase and decrease respectively. When annealing temperature is 900 ℃ and doped concentration is 7%, the phase is cubic without other phases, and the particle size of power is 43.34 nm.