影响电容器钽阳极漏电流因素分析

从钽粉纯度和颗粒结构分析了对钽阳极漏电流的影响.结果表明,在低烧结温度和短时间烧结下,降低钽粉金属杂质含量对改善漏电流显得尤为重要.而掺杂剂对漏电流的影响主要取决于掺杂种类.随着氧、碳等气体杂质的增加会增加漏电流,碳含量的影响表现尤为明显,与具有相当纯度和表面积的球形颗粒粉末相比较,片状粉具有较低的漏电流.从而可以通过降低钽粉中主要杂质含量或改变钽粉粒子结构等方法有效降低钽阳极漏电流。     

高比容钽粉烧结温度制度的探讨

本文结合35伏1万微法·伏/克比容钽粉的研制与近期国外研究工作,探讨了钽粉烧结温度对钽粉主要电性能的影响。讨论指出,在相应的技术措施配合下,降低烧结温度是高比容钽粉烧结制度的未来发展趋势。     

用于制造电容器的烧结钽阳极

美国一热技术公司设计了一种用于烧结钽阳极的专用炉。将钽粉末压制成适当的形状,然后放入炉中烧结,钽粉熔合,即可制造出钽阳极。钽阳极是制造闪光管的钽电容和钽电极的必需品。 这种专用炉具有直径 18厘米,高 20厘米的加热容积。其特征是采用钽加热元件和防护屏,并可以提供高的温度均匀性和高的真空度。其金属主控器借助于一个悬吊的圆柱形主电热元件,及可微调的电热元件,形成一个垂直的圆柱形加热腔。这种设计使工件更均匀地受热,并减少死角热损失。用于制造电容器的烧结钽阳极@日光     

电容器用钽粉的高比容化

简要地叙述了固体钽电解电容器高比容化、小型化趋势和生产高比容钽粉的方法.目前,1.5×104(μF.V)/g的高比容钽粉被小批量地使用,比容为(20～25)×104(F.V)/g的高比容钽粉正在开发中;宁夏东方钽业开发的(8～15)×104(μF.V)/g钽粉的含Fe、Ni和Cr的总量在25×10-6以下,Na含量低于5×10-6.钽粉是多孔的球形团聚颗粒,且具有很好的流动性,有合适的松装密度,粒径>180μm和<44μm的细粉含量少,比容高,直流漏电流低.这些钽粉可以满足制造钽缩小壳号的固体电解电容器,如一电容器厂家用FTW 100K钽粉制作的P壳号10V—15μF无引线模塑片状电容器,等效串联电阻(ESR)是行业中同型号电容器最低的,在100Hz下,它的ESR=3.5～5Ω,比市场上的其他电容器的平均水平低20%～40%.     

不同比容团化钽粉颗粒结构比较

利用透射电子显微镜和扫描电镜观察比较了几种不同比容团化钽粉的颗粒结构.观察发现:比容较低的钽粉其组成的一次颗粒较大,随着比容的增加,一次颗粒的平均粒径逐渐减小.但不论哪种比容的钽粉,一次颗粒间都以形成晶界形式结合,并弯曲扭转向三维空间发展,形成类似珊瑚状的多孔结构体,并具有较高的颗粒强度,且团化后的颗粒平均粒径基本相同.这种结构的团化钽粉颗粒对钽电解电容器阳极块的成型和提高电容器的容量十分有利.     

钠还原钽粉微观形态的观察及物理性能的调控

用扫描电镜和透射电镜观察了氟钽酸钾钠还原生产的钽粉的形貌和内部微观结构,它是一种以团聚体为基本粒子的粉末.通过生产工艺条件的调节和控制,生产出物理性能、电气性能适合于制作高性能的固体钽电解电容器的钽粉.     

实验设计方法改进钽丝用钽粉的酸洗工艺

针对宁夏东方钽业股份公司用钠还原的钽丝用钽粉酸洗工艺存在的问题.在原有工艺的基础上,通过用实验设计方法,确定了影响该工艺产品性能的关键因素为HNO3和HF体积分数以及酸洗时间,并得出了最佳的工艺条件.结果表明,在最佳条件下,不仅能有效降低钽粉中氧的质量分数,也能大大降低生产成本,提高生产效率,改善操作环境.     

钽铌中氢质量含量的测定

为了研究钽、铌中氢的测定方法,通过国际上较先进的美国LECO公司RH-404定氢仪,用惰性气氛脉冲加热熔融提取钽、铌粉及合金中的气体元素,然后采用热导检测法测定氢的质量.对仪器的主要参数进行了试验,最终确定了仪器的最佳检测条件.该方法可准确、快速地测定钽、铌粉及合金中氢的质量含量,检测仅需要5 min,且灵敏度和精密度都较高,是现在该行业中先进的检测方法.     

世界钽原料供应的现状与趋势

通过论述当今世界钽金属的主要应用领域，钽原料供应的主要种类，剖析了当今世界钽原料的主要来源－钽精矿以及提供钽精矿的钽矿床的成因特征，矿床类型及矿床开采的基本方法。结合钽矿物的物理性质、表面性质差异和矿物在各种酸碱溶液中的溶解度的变动等，提出了回收钽矿物的常用选别方法：重选法、磁选法、电选法、浮选法的适用范围、基本特点，并提出了钽矿床、钽矿物开采回收钽精矿的基本工艺。在分析所有种类钽资源的开采、回收成本的基础上，结合钽工业发展的实际，对五类钽原料的供应状况、供应趋势做了进一步的分析。     

激光粒度仪在测定钽粉粒度分布中的应用

使用带有湿法分散单元Hydro 2000MU的Mastersizer 2000激光粒径仪对电容器级钽粉的粒度分布进行了分析,主要考察了不同取样条件、遮光度、测量时间、泵速、超声时间等条件对测量结果的影响。最终确定了分析钽粉粒度分布的基本测量条件,通过试验验证了该检测条件具有很高的准确性和数据重现性。     

Effect of doping on microstructure and technical usage property of tantalum wire

Effect of different dopants and various dopants quantity at different annealing temperatures on microstructure of tantalum wire, bending of tantalum wire after sintering and bending after pressing into tantalum powder and sintering were investigated through observation of microstructure and testing of bending of tantalum wire after sintering and bending after pressing into tantalum powder and sintering. The results show that the recrystallization temperature of tantalum wire increases and the grain of microstructure can be reduced with the increase of dopants quantity. At the same time, the effect of dopant Ce on reduction of the grain is more obvious than that of dopant Ge. The bending time of tantalum wire after sintering increases with the increase of dopant Ge or Ce quantity. Under the same condition, the bending time of tantalum wire after pressing into tantalum powder and sintering worsens with the increase of oxygen content in tantalum powder. The bending time of tantalum wire doped with Ge and Ce after pressing into tantalum powder and sintering is better than that of tantalum wire doped with Ge, while that of tantalum wire doped with Ge is better than that of pure one when oxygen content in tantalum powder is not too high.     

Relation between doping and texture and property of tantalum bar and wire

Relation between doping and texture and property of tantalum bar and wire was carefully investigated by optical microscope, SEM fractograph, electron microprobe analysis, density test, observation of TEM and mechanical property test at room temperature. It is illustrated that the grain of tantalum bar after sintering reduces with the increasing of dopant quantity, and the effect of dopant Ce on reduction of the grain is more obvious than that of dopant Ge, even that sintering is becoming insufficient and the density of tantalum bar tends to be lower with the increaseing of dopant Ce. The recrystallization temperature of tantalum wire increases and the grain of texture reduces with the increaseing of dopants quantity. The tensile strength of tantalum wire at room temperature increases with the increasing of dopants quantity, while its elongation decreases with the increase of dopant Ge quantity and rises with theincrease of dopant Ce quantity. And the strengthening effect of dopant Ce is clearer than that of dopant Ge.     

影响钽丝硬度特性因素的研究

通过对钽丝维氏硬度的分析,研究了加工率、杂质质量分数、热处理工艺对钽丝硬度特性的影响.结果表明,随着杂质质量分数的增加,不论是加工态钽丝,还是结晶态钽丝,其纵横截面的硬度在增加;随着加工率的增加,加工态钽丝的硬度在逐渐增加,并且加工率越大,硬度越高;随着热处理工艺条件的变化,钽丝的再结晶程度趋于完全,其硬度在逐渐降低,随着结晶的完成,硬度又趋于稳定.确定了以上因素对钽丝硬度的影响程度,进而进行严格的过程控制,优化钽丝生产工艺.     

Density Measurement of Liquid Ni-Ta Alloys by a Modified Sessile Drop Method

The density of liquid Ni- Ta alloys was measured by using a modified sessile drop method. It is found that the density of the liquid Ni- Ta alloys decreases with the increasing temperature, but increases with the increase of tantalum concentration in the alloys. The molar volume of liquid Ni- Ta binary alloys increases with the increase of temperature ancl tantalum concentration.     

Influence of Ta on microstructure and abrasive wear resistance of laser clad NiCrSiB coating

A mixture of NiCrSiB alloy powder and tantalum (Ta) powder was used as laser clad material to improve abrasive wear resistance of the Ni-based coating. The microstructure and wear resistance of the coating were investigated. Addition of Ta element works to suppress the growth of coarse M₇C₃ carbide in the coating, resulting in a decrease in aspect ratio of coarse carbide. In the abrasive wear test, in situ synthesized TaC particles well bond with Ni-based matrix, and are hardly pull out from wear surface. Grooves on the worn surface of NiCrSiB coating are much deeper and sharper than those in the NiCrSiB+Ta composite coating. Also, a weight loss of the composite coating is much lower than that of the NiCrSiB coating. The wear resistance of the laser clad Ni-based coating is enhanced to a much greater extent through the addition of Ta. This is attributed to the in situ synthesized hard TaC particles of nearly equiaxed shape, the Ni-based matrix strengthened by Ta and the decrease in aspect ratio of the coarse brittle carbides.