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Niobium or tantalum powder and method for production thereof, and solid electrolytic capacitor

A powder and volume technology, applied in electrolytic capacitors, capacitors, circuits, etc., can solve problems such as increased number of processes, reduced adhesion strength, and influence on capacitor characteristics

Inactive Publication Date: 2003-08-20
CABOT SUPERMETALS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Furthermore, there is also a problem that carbon derived from the added polymer remains in the aggregated particles and affects the characteristics of the capacitor.
[0012] In addition, in the method described in JP-A-6-252011, there is a problem that the number of steps increases
[0013] In addition, in the method of reducing the pressing pressure when forming the molded body and leaving large pores, there is a problem that the adhesion strength between the electric wire of the electrode wire and the molded body decreases when forming the anode electrode.

Method used

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  • Niobium or tantalum powder and method for production thereof, and solid electrolytic capacitor
  • Niobium or tantalum powder and method for production thereof, and solid electrolytic capacitor
  • Niobium or tantalum powder and method for production thereof, and solid electrolytic capacitor

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0056] In a 50 L reaction vessel, 15 g each of potassium fluoride and potassium chloride for diluting the salt was added, and the temperature was raised to 850° C. to prepare a molten solution. To this melt, 200 g of potassium tantalum fluoride was added at a time, and after 1 minute, 58 g of dissolved sodium was added and reacted for 2 minutes. This operation was repeated 30 times.

[0057] After the reduction reaction was completed, it was cooled, and the obtained agglomerates were pulverized and washed with a weakly acidic aqueous solution to obtain tantalum particles. Further, it is refined with a washing liquid containing hydrofluoric acid and hydrogen peroxide. The yield of the reduced particles of tantalum was 1.6 kg.

[0058] The tantalum particles thus obtained have the following characteristics.

[0059] BET specific surface area 1.8m 2 / g

[0060] The average particle size of the primary particles is 200nm

[0061] Apparent average particle size 10μm (D 50 %)...

Embodiment 2

[0068] In the same manner as in Example 1, reduced tantalum particles were obtained. Then, 100 g of the reduced tantalum particles were pulverized with a microball mill in absolute ethanol. Thereafter, 3 g of magnesium hydride particles with a diameter of 7 μm and 20 mg of ammonium phosphate hexafluoride powder were added, mixed, and dried in a vacuum dryer at 50° C. to remove the alcohol component to obtain a solid. The amount of magnesium hydride added was about 20% by volume relative to the reduced particles. This solid was heated at 800° C. for 1 hour in a vacuum heating furnace, and further heat-treated at 1200° C. for 0.5 hour. Through such an operation, oxygen (deoxidation) on the surface of the tantalum is removed and thermally condensed at the same time.

[0069] Then, the aggregated particles were pulverized in an inert atmosphere, and the particle size was adjusted so that the average particle diameter was about 100 μm. Further, it is washed with a mixed acid of ...

Embodiment 3

[0073] In the same manner as in Example 1, reduced tantalum particles were obtained. Then, 2 g of fibrous magnesium metal (about 8 μm in diameter and 100 to 300 μm in length) was added to 100 g of the reduced tantalum particles, and after mixing well, phosphoric acid aqueous solution was added a little at a time while vibrating to obtain a lump. of solids. The amount of magnesium metal added was 14% by volume relative to the reduced particles. The amount of water required for agglomeration was 22 ml, and the content of phosphoric acid was 150 ppm with respect to the tantalum particles.

[0074] The solid was heated to 800° C. in a vacuum heating furnace, kept for 1 hour, and then heated to 1150° C. for 0.5 hour heat treatment. Thereafter, argon gas is passed into the furnace to oxidize and stabilize the tantalum metal.

[0075] Then, take out the solid matter from the furnace, coarsely pulverize it with a roller crusher in an argon flow, and further pulverize it with a pin ...

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Abstract

A niobium or tantalum powder characterized in that it comprises aggregates of primary particles of niobium or tantalum and has a pore distribution having a peak in the range of 1 to 20 mu m as measured by the mercury porosimetry. The niobium or tantalum powder comprises aggregates having large pores, which communicate with voids being present between primary particles and facilitate the permeation of an electrolyte over the whole of the inside of each aggregate. Accordingly, a solid electrolytic capacitor having an anode electrode prepared by using the niobium or tantalum powder has a high capacity and also a low ESR.

Description

technical field [0001] The present invention relates to a niobium or tantalum powder suitable for forming an anode electrode of a solid electrolytic capacitor, a method for producing the same, and a solid electrolytic capacitor. [0002] This invention is based on the patent (Japanese Patent Application No. 2000-165104) applied for in Japan, and the description content of this Japanese patent application is described as a part of this specification. Background technique [0003] In recent years, electronic integrated circuits have been required to be driven at lower voltage, higher frequency, and lower noise. For solid electrode capacitors, the requirements for lower ESR (equivalent series resistance) and lower ESL are gradually increasing. [0004] In a solid electrolytic capacitor, in order to manufacture an anode electrode composed of niobium or tantalum, aggregated particles with a size of about 40 to 100 μm are pressed and sintered in a state where about 70 volume % of ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F9/02B22F1/00B22F3/11B22F5/00C22C1/04C22C1/08C22C27/02H01G9/052
CPCB22F2999/00B22F2998/00B22F1/0007C22C1/045H01G9/0525B22F1/068B22F3/1134B22F3/1121B22F1/148B22F3/1103
Inventor 小田幸男水崎雄二郎
Owner CABOT SUPERMETALS
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