电容器用钽铌粉的研究进展

概括介绍了电容器用钽铌粉的研究进展,介绍了钽粉的3种钠还原制备方法的化学反应机理并进行了比较,同时还介绍了铌粉的制备方法,包括铝热还原法、电解还原法、蒸气还原法、钠还原法和金属热还原法;阐述了钽铌粉中杂质的测定方法以及有关钽铌粉的其它研究进展.     

电容器用铌粉和钽粉制备技术的进展

综述了铌粉和钽粉的现行生产工艺及几种新的还原方法,介绍了金属热还原反应中的电化学反应机理.钽粉的现行生产工艺几乎都用亨特法,铌粉则大部分采用铝热还原法生产.通过对亨特法还原条件、稀释剂组成等各种工艺参数的改进,已经可以制备纯度高、形态可控的金属钽粉.铌粉新还原方法的研究主要包括金属预成形热还原法、镁等蒸气还原预成形氧化物粉末的方法、镁或钠的蒸气还原氯化物蒸气的气相还原法、以液氨为介质在低温液相中均相还原铌或钽的氯化物的方法、反应媒介熔盐在强搅拌条件下的液体镁热还原金属氧化物的方法等.     

片式钽电容器的研究现状与发展趋势

综述了近期国内外片式钽电容器的研究现状,并对今后钽电容器的技术发展进行了展望,指出提高电容量或在相同容量下缩小体积,以及改进性能,特别是降低ESR将是今后钽电容器发展的方向,铌电容器的问世将拓宽钽电容器的应用范围,并成为电容器的一个新品种.     

钽、铌专利研究

介绍了钽、铌专利文献的检索方案及通过专利方法确定钽、铌技术领域中核心技术的原则,并依据这些原则确定钽、铌技术领域中的核心技术.通过对钽、铌专利的研究,提出宁夏东方钽业股份有限公司应采取的对策.     

铌电解电容器研究动态

铌电解电容器具有比铝电解电容器优越的性能,而价格比钽电解电容器便宜,在电解电容器领域颇有发展前途.综述了近年来国内外电容器用高比容铌粉和铌电解电容器最新研究发展动态、性能、制造方法及市场前景.     

钽铌工业生产及其展望

简述了钽、铌工业生产的新进展,重点介绍了钽、铌矿和钽、铌产品的生产技术进步和应用现状;分析了钽、铌产品的市场结构和价格走势,最后展望了钽、铌工业生产的未来发展.     

液体钽电容器电解质低温性能的研究

研究了液体钽电解电容器电解质的低温性能，并通过正交实验优选出了工作电解质配方。该工作电解质采用复合酸体系，同时加入适量的去极化剂以改善电容器性能。     

用液膜技术分离铌和钽

由煤油——仲辛醇——上胺体系组成的液膜技术分离铌(V)和钽(V),只要控制一定的料液相条件,就能快速,有效地分离。经一次处理能使含500ppm 的Ta_2 O_5几乎完全被萃取,而相同浓度的Nb_2 O_5其萃取率低于5%。     

2007年钽铌工业发展评述

评述了2007年中国钽铌工业的运行状况.在世界钽铌产品总需求持续增长的带动下,中国钽铌工业继续保持良好的增长势头,工业生产总值达到22.79亿元,销售收入达到23.37亿元,分别比上年增长了27.9%和28.8%.2007年是中国钽铌工业快速发展的一年,矿产量和冶炼品产量增加,高端钽铌产品的加工和出口快速增长.最后分析了中国钽铌工业发展中存在的突出问题,并提出了促进行业发展的措施.     

2200℃片式钽电容器真空烧结炉的研制

介绍了2200℃片式钽电容器真空烧结炉的基本结构、工作原理及烧结试验数据，并对该设备在片式钽电容器制造行业的作用进行了阐述。     

Nb元素对Ba0.5Sr0.5NbzTi1-zO3薄膜结构与性能的影响

采用溶胶-凝胶法制备了Ba0.5Sr0.5NbzTi1-zO3薄膜（Nb=0-4．12mol％）,采用HPAgilent 429A阻抗分析仪等测试方法研究了微量元素铌对Ba0.5Sr0.5NbzTi1-zO3（BSNT）薄膜介电性能的影响。当Nb分别为0-4．12m01％时,相对介电常数占,降低而介质损耗tanδ均得到了改善,当测试频率为1kHz,tanδ由0．09降低到0．067;居里温度Tm逐渐移向低温;在测试频率2．0-10MHz范围内,εr、tanδ均能表现出较好的频散特性。采用XRD、TEM等测试方法分析了薄膜的结构特征。薄膜为四方钙钛矿晶体结构,但Nb的溶入改变了晶胞参数的c／a比,减小了薄膜的晶粒尺寸,提高了薄膜的致密度。     

新型多纤维陶瓷电容器的设计

提出了一种新型多纤维陶瓷电容器(MFC)。MFC由众多纤维电容器并联而成，而每根纤维电容器由内电极(导电纤维)、介电层和外电极构成。理论分析表明，当纤维直径与介电层厚度相匹配时，MFC的电容比多层电容器(MLC)的电容大，而且MFC也具有更优异的抗击穿性能。     

高性能BaTiO_3/PVDF介电复合材料及其薄膜电容器应用

选用柔性高分子材料聚偏氟乙烯（PVDF）作为基体,纳米钛酸钡陶瓷（BaTiO3）作为填充相,采用简单的溶液共混以及流延工艺制备BaTiO3/PVDF薄膜。通过SEM观察了复合材料体系的微观结构,研究了BaTiO3/PVDF介电复合材料的介电性能。把所制备的BaTiO3/PVDF复合材料薄膜（70mm×30mm×25μm...     

Effect of tantalum addition on microstructure and optical properties of TiN thin films

Titanium nitride thin films were deposited by direct current magnetron sputtering with various tantalum (Ta) concentrations (2, 4 and 8 at.%). The films were characterized using UV/VIS spectrophotometer. Atomic force microscopy (AFM), high resolution transmission electron microscope (HRTEM) were used to observe the microstructure and X-ray photoelectron spectroscopy was used to investigate the core level and the valence band of the films. It was found that the film with 2 at.% Ta is more reflective in the infrared range and more transparent in the visible region (selective behavior). The AFM showed smooth nanostructured surface for the film without Ta addition. It was found that the films with 2 at.% Ta presented relatively coarser grains with larger roughness and the reflectance are not controlled by the surface morphology. Also, this film presented higher electrical conductivity. HRTEM analysis showed that 2 at.% Ta addition gave rise to well crystallized films with elongated nanocrystallites in comparison with the films having 0, 4 and 8 at.% Ta contents.     

Reliability comparison of tantalum and niobium solid electrolytic capacitors

This paper deals with a comparative investigation of tantalum and niobium solid electrolytic capacitors. Nb is an attractive replacement for Ta in solid electrolytic capacitors because it is lighter and cheaper than Ta. Although these two metals have much in common in their crystalline structure and physical and chemical properties, the electrical properties of Ta and Nb capacitors are different. Particularly, most Nb capacitors are characterized by an increase in direct current leakage during life testing. This causes parametric failure of Nb capacitors. On the other hand, the direct current leakage of Ta capacitors does not change significantly for a long time, but then increases sharply for some samples. Hence occasional catastrophic failures are typical for Ta capacitors. Nevertheless, the properties of high-CV Ta capacitors with low and high rated voltage approach the properties of Nb capacitors. The physical nature of these phenomena is discussed. © 1998 John Wiley & Sons, Ltd.     

在钽电解电容器多孔阳极体表面化学原位被覆聚乙烯二氧噻吩(PEDT)薄膜研究

研究在传统固体钽电解电容器多孔阳极体微孔内表面原位化学聚合制备PEDT导电聚合物薄膜的方法,通过对比所制有机固体钽电解电容器等效串联电阻(ESR)值的变化,讨论了采用化学原位聚合被膜过程中,受限空间里高分子链形成机理以及在受限条件和开放平面条件下被覆的聚合物薄膜导电性能的变化,采用SEM、AFM、X射线能谱对所制样品表面形貌变化以及多孔阳极体内部聚合物薄膜的被覆情况进行了研究。结果表明,在受限的空间里化学聚合反应生成的聚合物薄膜电导率会由于受限能的影响而降低,其影响程度相似于聚合溶液浓度的变化对聚合物薄膜电导率的影响。     

Formation of high asymmetric oxide tunnelling barriers on niobium and tantalum

A background tunnelling conductance that is only slightly voltage dependent and is asymmetric with respect to bias polarity has been observed for Nb/(niobium oxide)/Ag and Ta/(tantalum oxide)/Ag tunnelling junctions, indicating unusually high asymmetric barriers. These barriers are shown to result from chemisorption of anions on the oxide surface after countercontacting. The anions (representing less than one-tenth of a monolayer) must be supplied by grain boundary or bulk diffusion from the dirty silver surface. For tantalum, all stages of barrier formation are observable during thermal annealing or voltage annealing. For niobium, formation proceeds in the unmeasurably small resistance regime and only the final state is observable. The process is restricted to an oxide thickness below 20Å corresponding to room temperature oxidation times shorter than 1 h.     

滤波电容的选择和使用

介绍在电磁兼容测试当中，当连续干扰电压测试结果不满足相应标准时，采取相应的滤波电容抑制干扰的方法。     

Interdiffusion measurement of niobium and tantalum in iron base alloys

Abstract

Interdiffusion measurements of Nb and Ta in Fe base alloys have been made. Dilute alloys containing up to 0·6 wt-%Nb or 0·56 wt-% Ta were prepared. Diffusion couples of these alloys against pure Fe were made by spot welding. After vacuum annealing, diffusion profiles were obtained using electron probe microanalysis. The diffusion parameters were determined at one standard deviation using the Grube method. In austenite, interdiffusion of Nb is in good agreement with previous tracer diffusion data. The diffusion rate of Ta in austenite is approximately six times that for self-diffusion of Fe. Inferrite, diffusion of Ta produces a higher value of activation energy than other transition metals. Attempts to measure the diffusivity of Nb inferrite failed owing to the different levels of concentration and the presence of an intermetallic phase. However, a solubility of Nb inferrite of less than 0·24 wt-% is reported.

MST/1162