Polarization and fluctuation characteristics of tantalum solid electrolyte capacitors

A new method of tantalum capacitor testing and reliability prediction is presented based on the analysis of polarization mechanisms and noise characteristics. Polarization mechanisms of the Ta₂O₅ dielectric layer include electron polarization, fast ion polarization and ion relaxation polarization. Impurities usually add a fourth polarization type, migration polarization, which is effective in the mHz–kHz frequency region. © 1998 John Wiley & Sons, Ltd.     

两种去极化剂对液体钽电容器电解质改性的研究

采用添加去极化剂的方法,对液体钽电解电容器工作电解质的配方进行改性,通过正交实验,研制出了一种新型的电解电容器电解质,用其装配成规格100V/100μF的液钽电容器,高低温性能测试结果表明,以CuS04为去极化剂,电容器的漏电流较小、容量变化小;以Fe2(S04)3作为去极化剂,电容器损耗较小,低温阻抗小,两种去极化剂都在一定程度上使电容器的高低温特性得到了改进.     

铝电解电容器用电子铝箔的性能分析与比较

利用原子吸收光谱仪(AAS)、电子扫描电镜(SEM)、电子背散射技术(EBSD)、电化学工作站等方法对不同厂家生产的铝电解电容器用电子铝箔各方面的性能进行比较和分析.结果表明,国产铝箔在微量元素设计和杂质控制,立方织构控制方面已达到国外同类产品的先进技术水平,但表面加工质量,氧化层均一性和微量元素的分布控制方面与国外存在差距.     

聚吡咯在铝电解电容器中应用

报告由水溶性的APS作为氧化剂、NaDBS作为表面活性剂、p-NPh作为掺杂剂制备的PPY材料的多种电性能,采用SEM观察PPY表面形貌,发现大尺寸磺酸根离子的共存会降低PPY的颗粒尺寸,添加p-NPh提高PPY主链规整度进一步增加PPY的电导率,筛选出应用于卷绕式铝电解电容器的PPY最佳配方.     

改善有机片式固体钽电解电容器性能工艺研究

研究了在被膜过程中表面活性处理及掺杂对聚合物片式钽电容器容量、耐压、等效串联电阻(ESR)等特性的影响。研究结果表明表面活性处理后可以有效改善Ta2O5/PEDOT界面间的匹配,提高电容器容量引出效率;通过添加中间阻隔层(硅烷偶联剂)可以有效地阻挡杂质氧化性离子进入介质膜Ta2O5层,降低聚合物片式钽电容器的漏电流,提高耐压特性;实验结果表明在掺杂剂溶液的浓度为3%,补形成电压为赋能电压的70%时,能有效降低电容器ESR及漏电流。     

Improved thermophysical measurements on solid and liquid tantalum

Wire-shaped tantalum samples are resistively pulse heated as part of a coaxially constructed capacitor discharge circuit. With heating rates of more than 10⁹ K · s^–1, temperatures up to about 10,000 K are reached. The tantalum wire is contained, with water as the surrounding medium, in a high-pressure vessel with sapphire windows and a maximum pressure capability of 5 kbar. Time correlated measurements of the current through the wire and the voltage drop across it, as well as surface radiation and wire expansion, were performed to permit the determination of thermophysical properties of the solid and liquid tantalum.Paper presented at the Second Workshop on Subsecond Thermophysics, September 20–21, 1990, Torino, Italy.     

Critical oxygen content in porous anodes of solid tantalum capacitors

X-ray diffraction analysis of sintered porous anodes of solid tantalum capacitors and the current-voltage (I–V) characteristics of Ta2O5 amorphous layers formed on the anode surface have been performed. A strong correlation between a sharp increase of direct current in the I–V characteristics at some critical oxygen content and the creation of a saturated solid-phase solution of oxygen in tantalum was found. The appearance of a crystalline oxide Ta2O5 phase was detected in porous anodes at oxygen contents above the critical oxygen level. The decrease of effective radius below 1 m of Ta powder particles used in sintering leads to the size effect: the oxygen content in the porous anode after sintering exceeds the solubility limit. © 1998 Kluwer Academic Publishers     

直流电弧发射光谱法测定铌及铌合金中钽含量

采用直流电弧光谱仪对铌及铌合金中钽元素进行检测。通过试验确定满足分析条件的缓冲剂、样品与缓冲剂的配比及钽元素谱线并检测其精密度、准确度及检出限。结果表明,选择Li2CO3与碳粉1∶6混合作为缓冲剂,缓冲剂与样品比例为1∶2,钽元素的谱线为271.013 nm;加标回收率为94%~109%,测定值的相对标准偏差(测10次)均小于10%。     

Production and superconducting properties of laboratory scale NbTi and NbTiTa multifilamentary cables

A comparison of high field, low temperature superconducting properties between a Nb47^w/o Ti and two NbTiTa alloys as bases of laboratory scale cables was carried out Optimization cycles needed to obtain fair superconducting properties imply intermediate thermal treatments in the range 380–400°C during deformation at cold-work of 70%. The ternary alloys exhibit excellent ductile properties as do NbTi alloys. After an adequate optimization cycle the alloy Nb38^w/o Ti34^w/o Ta showed the best high field superconducting properties with values of more than 600 A mm^?2 at 12 Tesla and 2.15 K.     

铌、钽电容器性能分析

钽铌属于同族元素 都是阀金属材料,其介电常数分别为27、41,都可以用来制作电解电容器。本文使用铌和钽2种材料分别制作电解电容器,并通过容量损耗测试仪、漏电流测试仪、电子扫描电镜等分析仪器对其和始性能、偏压性能、温度特性、寿命特性及其电介质层的微观特性进行检测分析。结果表明使用铌材料同样可以得到性能较好的电解电容器。     

磁控溅射法制备低电阻率Ta薄膜研究

在无匹配层、常温、溅射气体为纯Ar的条件下,利用直流磁控溅射法在Si表面制备了Ta薄膜,系统研究了工作气压及直流功率对薄膜电阻率及微观结构的影响。分别用四探针测试仪、X射线衍射仪、原子力显微镜对不同条件下制备的Ta薄膜电阻率、相结构及表面形貌进行表征。结果发现,随溅射气压升高,高阻β相出现,薄膜电阻率随之增大;在相同溅射气压下,随着溅射功率的增加,薄膜电阻率先降低后升高。优化溅射工艺后制得的Ta薄膜的电阻率低至29.7μΩ·cm。     

基于高比容钽粉的聚合物片式电容器制备工艺研究

针对比容为50000～70000μF.V/g的较高比容钽粉,研究了导电聚合物聚3,4-乙烯基二氧噻吩(PE-DOT)作为阴极材料的有机片式固体钽电解电容器的制备工艺,通过调整阳极体制备及阴极被覆工艺等参数实现了PEDOT在高比容钽块表面的有效被覆,获得了各项性能参数良好的聚合物片式钽电解电容器。重点研究了压制密度、形成电流密度等参数及分段被膜工艺对聚合物片式固体钽电容器容量引出、等效串联电阻、漏电流等性能的影响,并讨论了相应的电容器工作机理。     

Properties of niobium nitride-based Josephson tunnel junctions

High T_c (16.8 K) niobium nitride thin films have been prepared by rf diode sputtering in N₂/Ar atmosphere and subsequent high temperature annealing. Josephson tunnel junctions have been made by thermal oxidation of the films. The geometry is defined by high resolution photolithography. The Josephson junctions have been characterized by magnetic field diffraction measurements and other techniques and are shown to be particularly suitable for applications especially in superconducting microwave integrated devices.     

钽基体上铜薄膜微观结构的分子动力学模拟

运用分子动力方法模拟了铜薄膜在钽（100）及（111）基体上沉积过程。结果表明沉积过程中铜薄膜的晶格位向取决于钽基体的晶格位向．在钽（100）面上，铜薄膜在不同的温度下分别沿（111）或（110）面生长，所形成的晶界与住错沿着薄膜的生长方向发展，薄膜表面的粗糙度与沉积温度有关，低温时表面粗糙度较大。而在钽（100）面上，铜薄膜的外延生长面为（100）面，位错沿（111）面分布，并只存在于界面附近，在铜薄膜的内部仅有少量的点缺陷，薄膜表面粗糙度较小并与沉积温度无关。     

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     

聚合物阴极钽电解电容器被膜技术研究

研究了以导电聚合物PEDOT作为阴极材料的高频低ESR有机片式固体钽电解电容器的被膜技术,重点讨论不同的聚合温度、掺杂浓度和驱溶温度对降低片式固体钽电解电容器ESR的影响.研究结果表明当聚合温度为0～10℃、掺杂浓度为3%(W),驱溶温度80℃时,将得到致密的主链掺杂有效的PE-DOT膜层,从而得到较低的ESR,并表现...     

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.     

High-pressure,high-temperature thermophysical measurements on tantalum and tungsten

A submillisecond resistive heating technique under high pressure (0.2 GPa) has been applied to the measurement of thermophysical properties of tantalum and tungsten metals in the solid and the liquid state. Agreement between previously published and most of the present results is good.Paper presented at the Ninth Symposium on Thermophysical Properties, June 24–27, 1985, Boulder, Colorado, U.S.A.     

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.