Ningxia Orient Tantalum Industry Co., Ltd.

National Engineering Research Center for Special Metal Materials of Tantalum and Niobium

Yuewei Cheng

Guoqi Yang

Aiguo Zheng

Yuezhong Ma

Xueqing Chen

Luntao Pan

Fukun Lin

Zhidao Wang

Yanjie Wang

Yinghui Ma

Guoqing Luo

Xueqing Zhang

Haiyan Ma

Jilin He

Zhongxiang Li

Ting Wang

Honggang Zhang

Lijun Li

Ning Wang

Chunxia Zhao

Hui Li

Shiping Zheng

Yanping Wang

Chunxiang Wang

Hongdong Liu

Baojun Zhu

Xuecheng Dong

Dejun Shi

Bin Li

Zekun Tong

Yan Yan

Xiaoyu Tian

Zhonghuan Zhao

Dongjie Zhang

Xuanyu Wang

Xia Li

A tantalum powder, a tantalum powder compact, a tantalum powder sintered body, a tantalum anode, an electrolytic capacitor and a preparation method for tantalum powder. The tantalum powder contains boron element, and the tantalum powder has a specific surface area of greater than or equal to 4 m/g; the ratio of the boron content of the tantalum powder to the specific surface area of the tantalum powder is 2&#x2dc;16; the boron content is measured in weight ppm, and the specific surface area is measured in m/g; Powder that can pass through a &#x3c1;-mesh screen in the tantalum powder accounts for over 85% of the total weight of the tantalum powder, where &#x3c1;=150&#x2dc;170; and the tantalum powder with high CV has a low leakage current and dielectric loss, and good moldability.

Tantalum powder and preparation method therefor

The present invention relates to a high-purity tantalum powder and a preparation method therefore. The tantalum powder has a purity of more than 99.995%, as analyzed by GDMS. Preferably, the tantalum powder has an oxygen content of not more than 1000 ppm, a nitrogen content of not more than 50 ppm, a hydrogen content of not more than 20 ppm, a magnesium content of not more than 5 ppm, and an average particle diameter D50 of less than 25 &#x3bc;m.

High-purity tantalum powder and preparation method thereof

The invention relates to the rare metal smelting field, and particularly, the present invention relates to a tantalum powder for preparing capacitors and a process for preparing the tantalum powder, and to a sintered anode prepared from the tantalum powder. As to the tantalum powder as provided by the invention, its primary tantalum powder has a BET of from 3.0 to 4.5 m/g. After the secondary agglomeration, the tantalum powder has a large particle size. The tantalum powder has an average Fisher sub-sieve size (FSSS) of 1.2 to 3.0 &#x3bc;m wherein as measured with a standard sieve mesh, more than 75% of tantalum powder has a +325-mesh, and a particle size distribution D50 of more than 60 &#x3bc;m, that is, the secondary particle size is high. A resultant capacitor anode prepared by sintering the tantalum powder of the invention at 1200&#xb0; C. for 20 minutes and then being energized at the voltage of 20 V has the specific capacitance of from 140,000 to 180,000 &#x3bc;FV/g and the residual current of less than 1.0 nA/&#x3bc;FV. Meantime, the invention provides an economical process for making the tantalum powder.

Tantalum powder and process for preparing the same, and sintered anode prepared from the tantalum powder

A method for preparing a tantalum power of capacitor grade, comprising: solid tantalum nitride is added when potassium fluotantalate is reduced by sodium. The method increases the nitrogen content in the tantalum powder, and at the same time improves the electrical performance of the tantalum powder. The specific capacitance is increased, and the leakage current and loss is improved. The qualification rate of the anode and the capacitor product is also improved. The method is characterized in that the nitrogen in the tantalum nitride diffuses between the particles of the tantalum powder, with substantially no loss, and thus the nitrogen content is accurate and controllable.

Method for preparing tantalum powder of capacitor grade with high nitrogen content, tantalum powder of capacitor grade prepared thereby, and anode and capacitor prepared from tantalum powder

The present invention relates to valve metal particles uniformly containing nitrogen and a method for preparing the same, and a valve metal green pellet and a sintered pellet made from the particles, and an electrolytic capacitor anode. The present invention provides valve metal particles uniformly containing nitrogen, wherein the difference ratio of nitrogen contents of particles is 20% or less. The present invention provides a process for preparing said valve metal particles uniformly containing nitrogen, wherein the raw material particles of the valve metal were heated in a nitrogen-containing gas at a temperature of 200&#xb0; C. or less for 2 hours or more. The present invention also provides a valve metal green pellet made from said valve metal particles. The present invention also provides a valve metal sintered pellet.

Valve metal particles uniformly containing nitrogen and the method for preparing the same, the valve metal green pellets and sintered pellets, and the electrolytic capacitor anodes

A method for spherically granulating and agglomerating metal particles such as tantalum and/or niobium powders is described in the present invention, which includes the steps of: a). comminuting the metal particles to form fine particles having D50 less than 50 &#x3bc;m; b). granulating the comminuted metal particles comprising volatile liquid, for example, tantalum and/or niobium particles comprising volatile liquid, to form wet spherical particles; c). still drying the wet spherical particles and removing volatile liquid to form flowable pre-agglomerated particles with increased bulk density; d). heat treating the pre-agglomerated particles; e). screening the heat treated powder to obtain the flowable agglomerated particles. The present invention provides a flowable spherical agglomerated metal particles, and especially tantalum and/or niobium particles having improved properties. The present agglomerated tantalum powder have a flow rate of at least about 2.0 g/sec, a BET surface area of from about 0.2 to about 6.0 m/g, a FSSS of at least 1.0 &#x3bc;m, a Scott bulk density of from about 1.2 g/cmto about 5.5 g/cm. The present agglomerated niobium powder have a flow rate of at least about 1.0 g/sec, a BET surface area of from about 0.5 to about 8.0 m/g, a FSSS of at least 1.0 &#x3bc;m, a Scott bulk density of from about 0.7 g/cmto about 3.5 g/cm. Said tantalum and/or niobium metal particles have improved pore size distribution of the sintered anodes and increased pellet crush strength. The present invention further provides an electrolytic capacitor anodes made from the tantalum and/or niobium particles according to the present invention having a capacitance of from about 5,000 &#x3bc;FV/g to about 300,000 &#x3bc;FV/g.

Methods for spherically granulating and agglomerating metal particles, and the metal particles prepared thereby, anodes made from the metal patricles

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Shizuishan, China

Yuewei Cheng