多层陶瓷电容器内电极镍粉的研究进展

近年来,贱金属电极片式陶瓷电容器(BME-MLCC)在MLCC产业中占有越来越重要的地位,到2002年,世界上已有超过70%的MLCC采用Ni贱金属内电极.介绍了MLCC用镍粉的研究进展及存在的主要问题,分析了内电极用镍粉性能对MLCC性能的影响,指出当前镍内电极MLCC存在的主要问题是由镍粉分散性、抗氧化性差和与陶瓷介质烧结行为不匹配等带来的,同时阐述了其解决问题的关键在于超细镍粉的制备和表面改性技术的研究.     

功能陶瓷材料研究的若干进展

本文介绍了几种典型铁电、压电陶瓷及其多层片式元件应用研究的若干新进展。基于过渡液相烧结机制的压电陶瓷材料具有烧结温度低、压电常数和介电常数高，介质损耗低等诸多优点。低烧多层压电变压器(MPT)以其低驱动电压、小体积、高升压比、薄型片式化等优点在液晶显示背光电源等方面获得应用。多层压电变压器及其背光电源具有高功率密度、高转换效率、薄型化和低成本等特点，通过有限元分析和多普勒激光扫描测振仪对MPT的振动模态与机电谐振特性等进行了分析与测定，为结构与性能优化提供了理论与实验依据。研究了钛酸钡基高介电常数温度稳定型多层陶瓷电容器(MLCC)及薄层贱金属内电极MLCC的关键材料组成以及制备技术，基于缺陷化学原理和无晶粒长大的致密化烧结动力学，通过调控受、施主掺杂和两段法烧结工艺，制备了在还原气氛烧结亚微米／纳米晶钛酸钡基陶瓷及其细晶化贱金属内电极MLCC。研究了多层复合功能陶瓷共烧行为、异质界面互扩散、致密化速率调控机制及共烧匹配技术，借助于差热膨胀仪研究了铁电陶瓷介质和内电极共烧失配的动力学根源，为制备高可靠的MLCC等多层元器件提供实验与理论依据。介绍了压电陶瓷超声微马达的结构与特性。     

MLCC用超细镍粉的制备方法及发展趋势

用超细镍粉代替多层陶瓷电容器内电极用贵金属是一种发展趋势.主要介绍了镍粉用作多层陶瓷电容器(MLCC)内电极的主要特点,详细介绍了生产超细镍粉的方法和工艺,并讨论了每种方法的优缺点.最后展望了MLCC内电极用超细镍粉的发展趋势.     

玻璃粉体系对MLCC用铜电极浆料性能的影响

多层陶瓷电容器(MLCC)在电子、通信、航天等领域应用广泛,MLCC铜端电极对MLCC的性能起到关键性作用.探究了玻璃粉体系对ML?CC铜端电极组织、性能的影响,分析了不同尺寸的玻璃体系对铜端电极的组织结构及耐酸性能的影响,研究表明:ZnO?B2 O3?SiO2体系制备的端电极烧结后在端电极与瓷体之间界面处形成较厚的过渡层,这有利于提高端电极在瓷体上的附着力,但端电极表面出现玻璃泡结构,不利于后续的电镀工艺.降低ZnO?B2O3?SiO2体系玻璃粉尺寸,烧结后界面处形成更厚的过渡层,但端电极表面出现了更多的玻璃泡.向D50为1.5μm的ZnO?B2 O3?SiO2玻璃粉制备的浆料内加入一定量的BaO?ZnO?B2 O3体系玻璃粉,烧结表面的玻璃泡结构经镀液腐蚀后消失,有利于镀层均匀附着在端电极上,从而更适合MLCC用铜端电极浆料的开发.     

多层片式陶瓷电容器电极浆料研究进展

简单介绍了多层片式陶瓷电容器MLCC(Multilayer Ceramic Capacitor)的组成、结构及要求.详细阐述了多层陶瓷电容器电极浆料的构成、功能及作用,重点介绍了导电相、玻璃相及有机载体的种类、性能和应用.最后叙述了MLCC电极浆料研究进展和发展趋势.     

功能陶瓷材料研究的若干进展

本文主要介绍几种典型的铁电、压电陶瓷及其多层片式元件应用研究的若干新进展.基于过渡液相烧结机制的压电陶瓷材料具有烧结温度低、压电常数和介电常数高,介质损耗低等诸多优点.低烧多层压电变压器(MPT)以其低驱动电压、小体积、高升压比、薄型片式化等优点在液晶显示背光电源等方面获得应用.多层压电变压器及其背光电源具有高功率密度、高转换效率、薄型化和低成本等特点,通过有限元分析和多普勒激光扫描测振仪对MPT的振动模态与机电谐振特性等进行了分析与测定,为结构与性能优化提供了理论与实验依据.研究了钛酸钡基高介电常数温度稳定型多层陶瓷电容器(MLCC)及薄层贱金属内电极MLCC的关键材料组成以及制备技术,基于缺陷化学原理和无晶粒长大的致密化烧结动力学,通过调控受、施主掺杂和两段法烧结工艺,制备了在还原气氛烧结亚微米/纳米晶钛酸钡基陶瓷及其细晶化贱金属内电极MLCC.研究了多层复合功能陶瓷共烧行为、异质界面互扩散、致密化速率调控机制及共烧匹配技术,借助于差热膨胀仪研究了铁电陶瓷介质和内电极共烧失配的动力学根源,为制备高可靠的MLCC等多层元器件提供实验与理论依据.介绍了压电陶瓷超声微马达的结构与特性.     

MLCC电极用铜粉的制备与表面改性研究进展

多层陶瓷电容器(MLCC)的重要发展方向之一是电极贱金属化,铜粉是一种较为理想的电极制作材料.介绍了MLCC电极铜粉制备和铜粉改性的研究现状,指出今后应加强对铜粉粒径控制技术和抗氧化性的研究.     

多层片式陶瓷电容器容量命中率的研究

多层片式陶瓷电容器（MLCC）容量命中率低是生产中普遍存在的问题，本文通过微观结构，金属层和介层厚度，以及工序因素分析，探讨了引起MLCC容量分散的主要原因，提出了工序中应控制的因素，为MLCC生产过程控制，提高容量命中率提供了依据。     

多层片式陶瓷电容器容量命中率的研究

多层片式陶瓷电容器 (MLCC)容量命中率低是生产中普遍存在的问题。本文通过微观结构、金属层和介质层厚度、以及工序因素分析 ,探讨了引起MLCC容量分散的主要原因 ,提出了工序中应控制的因素 ,为MLCC生产过程控制、提高容量命中率提供了依据。     

掺杂V2O3系PTC陶瓷电极的研究

本文采用一次烧渗法制备出掺杂Ｖ２Ｏ３系ＰＴＣ陶瓷的Ａｇ－Ｚｎ－Ｔｉ电极，测量了电极的电学性能，采用差热—失重分析、ＸＲＤ分析和电子探针Ｘ射线衍射显微分析等方法研究了电极的结构，同时对电极与陶瓷基体的接触状态进行了分析。研究结果表明：在电极与陶瓷基体间获得良好的欧姆接触，Ｚｎ和Ｔｉ固溶进入Ａｇ晶格而形成固溶体，Ｚｎ对形成欧姆接触具有重要影响。     

多层陶瓷电容器研究现状和发展展望

片式多层陶瓷电容器是新型片式元器件门类的主要品种之一.介绍了多层陶瓷电容器国内外研究现状和发展状况,重点介绍了镍内电极多层陶瓷电容器、高容量多层陶瓷电容器和高压多层陶瓷电容器,同时指出我国多层陶瓷电容器行业存在的问题和发展方向.     

贱金属内电极多层陶瓷电容器研发进展

经过30多年的发展,贱金属内电极多层陶瓷电容器(BME-MLCCs)已经成为多层陶瓷电容器的主流产品.简要论述国内外对贱金属内电极多层陶瓷电容器研发状况和研究方向,重点介绍镍内电极多层陶瓷电容器发展历程,并且指出我国BME-MLCCs行业存在的问题和发展方向.     

低烧钛酸钡基介电陶瓷的研究进展

低温烧结的BaTiO3基介电陶瓷具有降低能耗,抑制晶粒过度生长以及适合制造贱金属内电极多层陶瓷电容器等优点。本文综述添加助烧剂、高活性纳米粉体和烧结方法的改进等对钛酸钡基陶瓷烧结温度及其性能的影响。重点介绍了助烧剂的作用机制、分类和添加方式,并对其发展方向进行了展望。     

改性(Sr,Ca)TiO3基储能陶瓷介电及MLCC性能研究

工业级脉冲储能多层瓷介电容器(MLCC)是现阶段国内研制和生产电子启动装置的重要元器件, 针对国内主要有机薄膜电容器尺寸大、寿命短、可靠性较低的不足, 本研究采用传统固相反应法, 制备了SrTiO₃和CaTiO₃基的脉冲储能介质陶瓷材料, 研究了微量助烧剂掺杂, 以及Sr²⁺/Ca²⁺相互掺杂对陶瓷材料的介电性能的影响, 并进一步制备和研究了以(Sr,Ca)TiO₃为基体MLCC性能。实验结果表明: 通过加入质量分数1.0%的助烧剂, 引入微量Bi³⁺ 可取代Sr²⁺, 提高了SrTiO₃材料的介电常数, 而Bi³⁺对CaTiO₃基材料的介电性能无明显影响; Mn元素有效抑制高温烧结中Ti⁴⁺的还原, 降低介电损耗; 加入助烧剂有效降低瓷粉的烧结温度, 提高材料的致密性。(Sr_xCa_1-x)TiO₃体系的MLCC可保持较高的介电常数和较低的介电损耗, 当 x=0.4 时, 其介电损耗tanδ=1.8×10^-4, 击穿强度为59.38 V/μm, 高低温放电电流变化率为±7%, 放电稳定, 在常温和高温(125 ℃)下经1000次循环充放电实验均未失效, 是一种在不同电场强度下具有相对较优的容量稳定性以及较高可靠性的脉冲特性(Sr,Ca)TiO₃基电容器陶瓷介质材料。     

Solution-based aerosol deposition process for synthesis of multilayer structures

In this paper, we report the progress on 3D aerosol deposition of barium titanate (BTO) based multilayer ceramic capacitors (MLCC) using an automated process. Solution-based aerosol deposition is a promising direct-write method to produce three-dimensional (3D) structures at low temperatures. We utilize the combination of solution-based aerosol process and selective laser sintering (SLS) to develop 3D structures. The MLCC structure was synthesized on silicon substrate consisting of alternate layers of 0.5-1.0 μm thick silver electrode layer and 0.5-2 μm thick BTO ceramic. The effect of incident laser power subsequent to deposition (in the range of 105 mW and 930 mW) was systematically investigated revealing the changes in grain morphology as a function of local sintering. The results of this study are promising for development of on-substrate thin/thick film MLCCs.     

A study of ceramic addition in end termination of multilayer ceramics capacitors with cofiring process

The silver paste with ceramics addition as end termination was performed on multilayer ceramic capacitors (MLCC) based on ZnO–B₂O₃ + Zn_0.95Mg_0.05TiO₃ + 0.25TiO₂ ceramic (ZnBO-ZMT′) with Ag95–Pd05 internal electrodes. A green sheet was prepared by tape casting using the ZnBO-ZMT′ powders. Ag95–Pd05 was attached on the green sheet as an internal electrode. After lamination, the green chips were pre-sintered at 800 °C for 1 h, then samples were dipped the external electrodes and were cofired together at 900 °C for 2 h. There is no extra curing process, so the production cost may be cut down and thermal shock of the MLCCs may be reduced. To improve the mismatch between end termination and dielectric body during sintering, the silver paste with different amounts of ceramics, e.g., 20, 30 and 40 wt.%, was added in this study. The mechanical and electrical properties of the MLCCs were investigated subsequently. The results showed that end termination with 40 wt.% ceramic addition has good performances on mechanical properties of MLCC, but equivalent series resistance (ESR) is a little bit higher compared to end termination with 20 and 30 wt.% ceramic addition.     

ZnS:Mn沉积温度对薄膜电致发光器件亮度的影响

采用丝网印刷技术,在Al2O3陶瓷基板上印刷、高温烧结内电极及绝缘层,制备出陶瓷厚膜基板,进而制备了新型厚膜电致发光显示器(TDEL).整个器件结构为陶瓷基板/内电极/厚膜绝缘层/发光层/薄膜绝缘层/ITO透明电极.研究不同基板沉积温度对发光层性能的影响,并对器件的亮度-电压、亮度-频率进行测量.结果显示较高的ZnS:Mn沉积温度明显提高了无机发光器件的发光亮度.其原因主要是由于高的沉积温度提高了ZnS:Mn的成膜质量,提高膜层微晶尺寸大小,从而发光亮度提高.但是我们发现温度继续提高的同时,器件发光亮度趋于饱和,分析原因是由于掺杂Mn浓度过高,影响了发光效果.     

Advanced characterization of mechanical properties of multilayer ceramic capacitors

Characterization of the mechanical properties of small components is a significant issue. For the multilayer ceramic capacitor (MLCC), direct loading by conventional facilities is not suitable because of its small size. To date, the standard method used to determine MLCC’s mechanical properties is board flex test; i.e., mounting the capacitor onto a printed circuit board (PCB) and applying bending to the entire system. Failure is defined as cracking or capacitance loss of the MLCC when the mounted PCB is subjected to a specified deflection, and the measurements are usually performed after the test. In this case, characterization of the mechanical properties of MLCCs is qualitative. The purpose of the present study was to quantitatively characterize the mechanical properties of MLCCs. Specifically, the acoustic emission was used to detect cracking of MLCCs during the board flex test. To confirm cracking-induced acoustic emission, telemicroscope was used to perform the in situ observation of cracking. Finite element analyses were also performed to analyze the stress field resulting from the test to compare with the observed cracking path. In addition, nanoindentation was used to explore the mechanical properties of the constituents of MLCCs in the nanoscale. Our work not only allows identification and understanding of the fracture origin, but also provides guidelines in the material design.     

Design and fabrication of multilayer actuator using floating electrode

PZT (lead zirconate titanate) multilayer actuators were of interest due to their small volume, fast response, low power consumption and low driving voltage. But this multilayer actuator had some problems. However, due to internal stress around electrodes, crack and delamination were very important issues. Around the edge of conventional inter-digital electrodes, non-uniform electric field generates the stress concentration, which causes the ceramic crack and delamination. The internal stress distribution in multilayer actuator was analysed by a numerical simulation. And by using float electrode, multilayer actuator was manufactured to decrease internal stress concentration of inter-digital electrode. The float electrode could suppress the electric field concentration and cracking in the actuator.

Destruction mechanism in multilayer ceramic actuators has been investigated under cyclic electric fields. Crack propagation has been observed dynamically by using optical microscopy, and the accompanying characteristic of acoustic emission was measured.