PZT铁电薄膜电极材料研究进展

近几年,PZT铁电存储器的商业应用受到了广泛关注,但PZT电容器的疲劳现象已成为其应用的严重障碍,变换电极是改善PZT电容器抗疲劳特性的有效方法.系统地介绍了PZT铁电薄膜用电极材料的结构、性能及其特点,比较了不同电极材料对PZT铁电薄膜结构及铁电性能的影响,并对导电金属氧化物电极改善抗疲劳特性的机制进行了一定的分析,提出了电极材料的主要问题和发展方向.     

PZT压电陶瓷谐振器用银电极浆料

本文研究了中频压电陶瓷谐振器用银电极浆料的制备工艺，并对银膜在烧结过程中微观结构的变化进行了分析。新型的电极银浆用于制作PZT压电陶瓷电极，经高温烧线后，银膜表面光亮、平滑、致密。电极的谐振阻抗≤2．5Ω，机械品质因素＞1500。通过极化后的电学参数满足特定产品的性能要求。     

晶硅太阳能电极银浆用银粉的后处理方法综述

随着晶硅太阳能电池制备技术的发展,对其导电银浆用银粉的形貌、分散性、表面性质和粒径分布等提出了更高的要求。除了提高银粉本身结构特性外,银粉的后处理是解决以上问题并能实现其应用的关键步骤。在分析国内外近20年来40余篇相关文献的基础上,总结了晶硅太阳能电极银浆用银粉的后处理方法,主要包括表面改性(化学改性法、机械复合法及原位生成粒子法)和银粉粒度分级处理(机械振动筛分级和气流分级),并对上述方法的优缺点进行了总结分析与展望。     

高分散球形银粉制备研究

采用液相化学还原法,以一乙醇胺为分散剂和p H值调节剂,用对苯二酚直接还原硝酸银制备高性能球形银粉。研究了一乙醇胺添加量对银粉性能的影响,在一乙醇胺添加量为硝酸银质量的250%时,可以制得平均粒径D50为1.49μm,松装密度达到2.16 g/cm3的规则球形银粉。通过X射线衍射(XRD)和能谱仪(EDS)分析表明,银粉纯度高,杂质含量少。扫描电镜(SEM)表征发现,银粉结晶度高,呈规则的球形颗粒,团聚少,分散性能好。将所得银粉制备成太阳能电池电极银浆,通过丝网印刷在硅片上,测量其方阻为5.26 m?/□,满足制作太阳能电池电极银浆的电性能要求。     

电极表面处理和电极材料对微型点焊时电极粘附的影响

研究了电极表面处理和电极材料对镀镍钢板和镍板微型点焊时电极粘附的影响。结果表明：电极表面涂敷TiC后能提高CuCrZr电极和GlidCop60电极的抗粘附性能，其原因是涂层中的TiC能阻碍电极和镀镍板之间的局部焊接；GlidCop60电极的抗粘附性能优于CuCrZr电极的抗粘附性能，其原因是弥散分布于GlidCop60电极中的Al2O3能阻碍电极和镀镍板之间的局部焊接。     

不同退火工艺Pt电极上沉积溶胶凝胶Pb(Zr,Ti)O_3薄膜的织构演化(英文)

利用溶胶凝胶工艺在Pt电极上沉积了PZT薄膜,选用传统退火及其快速退火工艺制备两种Pt基底(CTA-Pt和RTA-Pt),并采用X射线衍射广角及其ù扫描技术分别研究了Pt电极退火工艺对溶胶凝胶PZT结构及其织构演化的影响.研究结果显示:在传统退火工艺制备Pt电极上沉积的薄膜为(111)择优取向,而在快速退火工艺制备Pt电极上沉积的薄膜表现为(100)织构;分析表明PZT薄膜的织构演化可能与Pt电极在不同退火工艺下的内应力差异有关.     

光伏电池正极银浆用球形银粉的制备

采用化学还原法制备光伏电池正极银浆用球形银粉,通过扫描电镜(SEM)和激光粒度仪表征了银粉的形貌和粒度,研究还原剂的种类、表面活性剂浓度以及反应时间等工艺条件对银粉粒度及形貌的影响。结果表明,采用抗坏血酸作还原剂、聚乙烯吡咯烷酮(PVP)作分散剂时,可以得到分散性好、粒度约为1.5μm的球状银粉。将该银粉制成浆料,印刷、烘干并烧结后,表征了电极形貌,用四探针电阻仪测得烧结银层的方阻5 m?/□,可满足太阳能电池的电性能要求。     

混合银粉对导电银浆烧结膜层附着力的影响

采用4种不同规格的银粉,并优选其中2种银粉按不同比例混合,制备得到不同氧化锌压敏电阻器用导电银浆;对烧结后的银浆样品进行表面形貌分析和附着力测试,并比较烧结温度对附着力的影响。结果表明,将2种单一银粉混合制备所得浆料烧结所得电极膜层表面更致密平整,附着力增加;调整合适的混合质量比,可以得到具有最大附着力的导电银浆;其机制可能是浆料在烧结过程中不同粒径的银粉相互填充间隙,产生协同作用,提高了膜层致密度。所得银浆最佳烧结温度为550~650℃。     

导电浆料用银粉的研究

研究了一种制备光亮片状银粉的新工艺:用添加表面剂的甲醛和苯甲醛混合悬浮液作还原剂,还原碱金属氰化银,获得平均粒径9.6μm的光亮片状银粉;并探讨其还原机理。将还原制备的银粉调成银浆,其性能达到技术指标。     

粗银法制备高纯度片状银粉的研究

片状银粉是独石电容器、滤波器、碳膜电位器、钽电容器、薄膜开关、半导体芯片等电子元器件的主要电极材料,其颗粒度及分布、单片厚薄以及银粉纯度对以银粉为导电相的电子浆料和电子元器件的电性能影响很大[1-3].随着信息产业的发展,片状银粉和电子浆料的生产已经成为一个特定的工业行业.片状银粉的制备方法很多,通常是将适当的银盐用化学方法还原成超细银粉后,再用机械球磨的方法将球形颗粒用强力打压成片状.由于还原过程和球磨过程的可变因素很多,不同工艺、不同生产者、甚至同一工艺同一生产者生产的不同批次的片状银粉,在技术指标上也往往难以一致.目前有关片状银粉的研究主要集中于片状银粉颗粒大小、表面形貌和电性能上[4,5],对生产片状银粉过程中如何控制银粉纯度、降低生产成本和稳定片状银粉质量等方面研究较少.本文在实践基础上,提出一种以粗银作为原料生产高纯度片状银粉的新工艺,所得产品纯度很高,工艺稳定性好,生产成本可以明显降低,适用于中小企业生产.     

Preparation of doping titania antibacterial powder by ultrasonic spray pyrolysis

Doping titania powders were synthesized by ultrasonic spray pyrolysis method from an aqueous solution containing H2TiF6 and AgNO3. The effects of the processing parameters on particle size distribution, structure, and morphology of doping particles were investigated. The results show that aggregation-free spherical particles with average diameter of 200-600 nm are obtained and the particle size of the powder can be controlled by adjusting the concentration of solution. The experimental approach indicates that the size and the value of standard deviation of particle size increase from 210 nm to 450 nm and from 0.46 to 0.73 respectively with the increase of the titanic ion concentration from 0.05 to 0.4 mol/L. Composite TiOF2 is obtained when the pyrolysis temperature is set to be 400 ℃. With increasing pyrolysis temperature from 400 ℃ to 800 ℃, the crystal size of titania powders increases from 14.1 to 26.5 nm and TiOF2 content of powder decreases dramatically. The property of ion released from powder is affected significantly by the pyrolysis temperature, and the amount of fluorine ion and silver ion released from powder decrease with increasing pyrolysis temperature. The optical property of doping titania powders is not affected by pyrolysis temperature. Antibacterial test results show that composite powders containing more fluorine ions exhibit stronger antibacterial activity against E.coli.     

Application of nanotechnology in a silver／graphite contact material and optimization of its physical and mechanical properties

By applying nanotechnology, a new type of silver/graphite (AgC) electrical contact was fabricated and charac-terized. The AgC coating powders were obtained through high-energy ball milling and reducer liquid spraying-coating method. The as-prepared powders were examined by transmission electron microscope (TEM), scanning electron micro-scope (SEM), and X-my diffraction (XRD). The results show that the thickness of graphite flakes milled for 10 h is about 50-60 nm and the AgC coating powders exhibit flocculent structure with quite free and homogeneous intemal micropores.XRD implies that the average crystalline size of silver in coating powders is about 50 rim. The mechanical and physical properties of this newly developed AgC contact made from the above-mentioned nanocrystalline powders by traditional powder metallurgy technique were measured. Compared with its counterparts made from other techniques, the properties of this new AgC contact have been optimized. High surface energy and high-energy interfaces of the nanocrystalline AgC coating powders provide powerful driving force for sintering densification. Moreover, the flocculent structure of the pow-ders is also an important factor to acquire fine density ratio.     

不同体系水热制备银氧化锡复合粉体的研究

分别采用氨水和柠檬酸作为溶液中银离子的配体,草酸、亚硫酸钠和柠檬酸作为还原剂,水热制备Ag-SnO2复合粉体。对Ag-SnO2复合粉体进行了差热分析、X射线衍射、扫描电镜和元素面扫描分析。结果表明:不同体系均可水热制备银氧化锡复合粉体。在以氨水为配体,分别以亚硫酸钠和草酸为还原剂的体系中,银和二氧化锡沉积完全。以亚硫酸钠为还原剂的体系中所得复合粉体为片状结构,厚度约为300nm,而以草酸为还原剂所得复合粉体为球形结构,粒径约为100nm。以柠檬酸为配合剂和还原剂的水热体系中二氧化锡沉积不完全,所得复合粉体为不规则球形,粒径较小,约为30nm。     

通孔柱银浆用超细银粉的制备研究

通孔银浆料是低温共烧陶瓷(LTCC)基板配套的系列电子浆料中必不可少的一种材料,对银粉有很高的要求。用抗坏血酸还原体系制备银粉,研究硝酸银溶液浓度、p H值、还原剂浓度对银粉形貌及粒度分布的影响,采用扫描电子显微镜对制备的银粉进行表征分析,选取3种不同类型的银粉调制成通孔银浆进行匹配性试验。结果表明,均一性、分散性良好且平均粒径为2.0μm的球形银粉具有较好的应用潜力。     

Characteristics of nano-sized silver–glass composite powders prepared by flame spray pyrolysis

Nano-sized silver–glass composite powders were directly prepared by high-temperature flame spray pyrolysis applying ultrasonic spray generator. The silver–glass composite powders with various glass contents had nanometer size, spherical shape and non-aggregation characteristics. The mean size of the silver–glass composite powders was 56 nm. The nano-sized silver–glass composite powders had pure Ag crystal structures irrespective of adding amounts of glass. The silver conducting films formed from the nano-sized silver–glass composite powders had dense structures at firing temperatures between 400 and 500 °C. The silver conducting films formed from the nano-sized silver–glass composite powders had lower sheet resistivities than those formed from the nano-sized silver powders irrespective of the firing temperatures. The sheet resistivities of the silver conducting films formed from the nano-sized silver–glass composite powders with 1 wt% glass content were 53, 16 and 11 mΩ/sq at firing temperatures of 400, 450 and 500 °C, respectively.     

导电粉体堆砌体积电阻率的测试方法研究

设计了一种金属粉体导电特性的表征方法,以银粉为测试样本,采用堆砌体积电阻率表征粉体的导电特性。分别考察了填充量、测试负荷、测试稳定时间等因素对银粉堆砌体积电阻率的影响。结果表明当银粉填充量为4 g、测试负荷为800 g和测试稳定时间为30 min时,所得实验结果可以准确反映银粉的堆砌体积电阻率。     

Preparation of flake AgSnO2 composite powders by hydrothermal method

Silver-tin oxide composite powders and silver powders were synthesized by hydrothermal method using NHs to complex Ag^＋, SO3^2- to reduce Ag（NH3）2^＋ and Na2SnO3 as the source of tin. The powders were characterized by XRD, SEM and EDX. The results show that there are macroscopic and microscopic differences between two kinds of powders. Spherical silver powders are 3μm in diameter, and silver-tin oxide composite powders are mainly flake of about 0.3μm in thickness. Silver crystal in silver-tin oxide composite powders is preferentially oriented in the （111） crystallographic direction and its oriented index is 2.581. Crystal lattice parameter of silver crystal of silver tin-oxide composite powders is 0.409 34 nm, larger than 0.408 68 nm of silver powders. The XPS analysis shows that silver in silver-tin oxide composite powders is metallic silver and tin oxide in silver tin-oxide composite powders has the red shift for Sn^4＋（3d（5/2）） and O^2-（1s）.     

Preparation of ultrafine silver powders with controllable size and morphology

The ultrafine silver powders were prepared by liquid reduction method using Arabic gum as dispersant. The effects of different dispersants, pH values, and temperature on the morphology and particle size of silver powders were investigated. It is found that Arabic gum can better adsorb on silver particles via chemical adsorption, and it shows the best dispersive effect among all the selected dispersants. The particle size of silver powders can be finely tuned from 0.34 to 4.09 μm by adjusting pH values, while the morphology of silver powders can be tuned by changing the temperature. The silver powders with high tap density higher than 4.0 g/cm³ were successfully prepared in a wide temperature range of 21.8–70 °C. Especially, the tap density is higher than 5.0 g/cm³ when the temperature is optimized to be 50 °C. The facile process and high silver concentration of this method make it a promising way to prepare high quality silver powders for electronic paste.     

还原法制备银包铜粉主盐添加工艺及镀层沉积过程研究

用葡萄糖作为还原剂制备银包铜粉。在还原法镀银过程中,主盐溶液以不同的工艺添加可得到不同微观形貌和表观颜色的银包铜粉,用扫描电镜、能谱仪对银包铜粉进行表征,并用滴定法计算不同添加工艺制备的银包铜粉的含银量,确定了较优的主盐添加工艺;同时,通过在施镀过程中阶段性取粉观察,对银包铜粉镀层的沉积过程进行了分析。     

直流电弧等离子体法制备超细Ag粉研究

采用自行研制的高真空双枪直流电弧金属纳米粉连续制备设备,制备了高纯度的超细银粉,并采用正交试验的方法研究了各工艺参数对粉体产率及粒径分布的影响。利用X射线衍射（XRD）、透射电子显微镜（TEM）和相应选区电子衍射（SAED）以及Simple PCI软件对样品的成分、形貌、晶体结构和粒径分布进行了分析。结果表明：所得银粉纯净无污染,属多晶型结构,平均粒径在38-220nm范围内,粒径分布窄;最大产率比同类研究结果提高了近17倍;电流和充气压力分别是影响产率和粒径分布的显著性因素。