JP2002173371A - Powder for capacitor, sintered body formed by using the same powder and capacitor manufactured by using the same sintered body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an earth-acid metal powder which enables the manufacture of a capacitor having a large capacity per unit mass and good leakage current characteristics, also to provide a sintered body formed using the earth-acid metal powder and further to provide a capacitor using the sintered body. SOLUTION: This powder has a 0.2-5 μm average particle size and consists essentially of niobium and/or tantalum and also contains 0.01-15 atomic % zirconium. This sintered body is formed from the powder. This capacitor consists of the sintered body used as one of electrodes of the capacitor, a dielectric body formed on the surface of the sintered body, and the other electrode placed on the dielectric body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal earth (mainly niobium or tantalum) powder having a large capacity per unit mass and capable of producing a capacitor having good leakage current characteristics. More specifically, containing a specific amount of zirconium, niobium powder, tantalum powder and niobium-tantalum alloy powder, sintered bodies using these powders,
And a capacitor using the sintered body.

[0002]

2. Description of the Related Art Capacitors used in electronic devices such as mobile phones and personal computers are desired to be small in size and large in capacity. Among such capacitors, a tantalum capacitor is preferably used because of its large capacity for its size and good performance. Generally, a sintered body of tantalum powder is used as an anode body of a tantalum capacitor. In order to increase the capacity of these tantalum capacitors, it is necessary to increase the mass of the sintered body or to use a sintered body in which the surface area is increased by pulverizing tantalum powder.

[0003] In the method of increasing the mass of the sintered body, the shape of the capacitor is inevitably increased, and the demand for miniaturization is not satisfied. On the other hand, in the method of increasing the specific surface area by pulverizing the tantalum powder, the pore diameter of the tantalum sintered body is reduced, and the number of closed pores is increased in the sintering step, so that impregnation of the cathode agent in a later step becomes difficult. In order to solve these drawbacks, a method of reducing the number of closed holes in the sintering stage, a method of forming a capacitor using a material having a higher dielectric constant than tantalum, and the like can be considered. There is niobium as a material having a large dielectric constant.

Japanese Patent Application Laid-Open No. 55-157226 discloses that an agglomerated powder of niobium fine powder (primary powder) having a particle size of 2.0 μm or less is pressed and sintered, and then formed and sintered. There is disclosed a method for manufacturing a sintered element for a capacitor in which a body is finely cut, a lead portion is joined thereto, and then sintered again. However, this publication does not show the details of the characteristics of the capacitor using the sintered element.

[0005] US Pat. No. 4,084,965 discloses a niobium ingot which is hydrogenated and pulverized to obtain 5.1 μm niobium powder, and a capacitor using the niobium powder is disclosed. Value (hereinafter abbreviated as LC value) is large and is not practical. JP-A-10-24
JP-A-2004-2004 discloses that the LC value is improved by nitriding a part of niobium powder. However, when a high-capacity capacitor is made from a niobium sintered body using niobium powder having a small particle diameter, a capacitor having a specific LC value may appear.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a capacitor powder capable of providing a capacitor having a large capacity per unit mass and a small leakage current value, a sintered body using the same, and a sintered body using the same. An object of the present invention is to provide a capacitor using a combination.

[0007]

Means for Solving the Problems As a result of intensive studies on the above-mentioned problems, the present inventor has found that a specific amount of zirconium is converted into niobium,
By containing tantalum and niobium-tantalum alloy, it is possible to maintain a large specific surface area even when sintering using powder having a small average particle size. The inventors have found that a stable capacitor having a large capacity and a low LC can be obtained, and the present invention has been completed. That is, the present invention relates to the following capacitor powder, a sintered body using the same, and a capacitor using the same.

[0008] 1. A capacitor powder containing zirconium and mainly containing niobium and / or tantalum. 2. 2. The powder for a capacitor as described in 1 above, containing 0.01 to 15 atomic% of zirconium and containing niobium and / or tantalum as a main component. 3. 3. The powder for a capacitor according to the above 1 or 2, comprising niobium as a main component. 4. 3. The powder for a capacitor according to 1 or 2 above, mainly comprising tantalum. 5. 2. The powder for a capacitor as described in 1 above, which mainly comprises a niobium-tantalum alloy. 6. The above-mentioned 1 to 5, wherein the average particle size is 0.2 μm to 5 μm.
Powder for capacitors according to any one of the above. 7. 6. The powder for a capacitor according to any one of the above items 1 to 5, having a specific surface area of 0.5 to 15 m ² / g. 8. Niobium and / or tantalum are partially nitrogen, carbon,
6. The powder for a capacitor according to any one of the above 1 to 5, which is combined with at least one of boron and sulfur. 9. An average particle diameter of 20 to 500, which is obtained by granulating the powder for a capacitor according to any one of 1 to 8 above.
μm capacitor powder. 10. A sintered body using the powder for a capacitor according to any one of 1 to 9 above. 11. 11. The sintered body according to the above 10, wherein the specific surface area is 0.5 to 5 m ² / g. 12. 12. A capacitor comprising the sintered body according to 10 or 11 as one electrode, a dielectric formed on the surface of the sintered body, and the other electrode provided on the dielectric. 13. The capacitor according to the above item 12, wherein the dielectric comprises niobium oxide and / or tantalum oxide. 14． 14. The capacitor according to 13 above, wherein the niobium oxide and / or tantalum oxide is formed by electrolytic oxidation. 15. 13. The capacitor according to the above 12, wherein the other electrode is at least one material selected from an electrolytic solution, an organic semiconductor, and an inorganic semiconductor. 16. The other electrode is made of an organic semiconductor, the organic semiconductor is an organic semiconductor composed of benzopyrroline tetramer and chloranil, an organic semiconductor containing tetrathiotetracene as a main component,
Organic semiconductor containing tetracyanoquinodimethane as a main component,
And the following general formula (1) or (2)

Embedded image (Wherein, R ^{1 to} R ⁴ may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, and X represents oxygen R ⁵ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms and is present only when X is a nitrogen atom, and R ¹ and R ² and R ³ and R ⁴ are bonded to each other. At least one organic semiconductor selected from the group consisting of organic semiconductors containing as a main component a conductive polymer obtained by doping a polymer containing two or more repeating units represented by the following formula: 16. The capacitor according to the item 15, wherein 17． 17. The capacitor according to the above item 16, wherein the organic semiconductor is at least one selected from polypyrrole, polythiophene, and substituted derivatives thereof.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a niobium powder, a tantalum powder, and a niobium-tantalum alloy powder for a capacitor containing zirconium. These powder materials exhibit similar performance. Explanation will be given using the body as an example.

The capacitance of a capacitor is generally expressed by the following equation.

C = ε × (S / d) (C: capacitance, ε: dielectric constant, S: specific area, d = distance between electrodes) where d = k × V (k: constant, V: chemical conversion) Voltage), C = ε × (S / (k × V)), and C × V =
(Ε / k) × S is derived. Therefore, the specific area (S)
The capacity can be increased by increasing.

The first means for increasing the specific surface area of the sintered body used for the capacitor is to reduce the particle size of the powder used for the capacitor. In the present invention, the specific surface area of the powder can be increased to a practical level by setting the average particle size of the primary particles of zirconium-containing niobium powder for producing a sintered body to less than 5 μm.

Table 1 shows the particle size and specific surface area of the zirconium-containing niobium powder (pulverization method) produced by the present inventor as an example.

[Table 1] The average particle size (D ₅₀ ) in Table 1 refers to a particle size value at which the cumulative mass% measured using a particle size distribution analyzer (trade name “Microtrac”) is 50 mass%, and the specific surface area is BET.
The value measured by the method.

As is clear from Table 1, the specific surface area of zirconium-containing niobium powder can be increased by reducing its average particle size. However, the average particle size of zirconium-containing niobium powder is reduced to less than 0.2 μm. Then, when a sintered body is produced, the pore diameter becomes small and the number of closed holes increases, so that impregnation of the cathode agent in a later step becomes difficult.
As a result, the capacity cannot be increased as a result,
Not practical. When the average particle size is 5 μm or more, a large capacity cannot be obtained because the specific surface area is small.
Therefore, in the present invention, the average particle size of the zirconium-containing niobium powder is preferably 0.2 μm or more and less than 5 μm.

The second means for increasing the specific surface area of the sintered body used for the capacitor is to use a powder having a small average particle size while suppressing the formation of closed pores during sintering to obtain a specific sintered body. The surface area should not be reduced. Usually, if the sintering temperature is lowered, the specific surface area can be maintained, but if the sintering temperature is lowered, the strength of the sintered body is reduced and the sintered body is easily broken. In the present invention, a niobium powder for a sintered body, a tantalum powder or a niobium-tantalum alloy powder, by including a specific amount of zirconium, a sintered body having a large specific surface area at a sintering temperature at which required strength is obtained. It can be. Table 2 shows the specific surface area of one example of the zirconium-containing niobium sintered body produced by the present inventors and the specific surface area of the niobium sintered body not containing zirconium.

[0015]

[Table 2]

As is clear from Table 2, when sintering is performed at a temperature at which practical strength is obtained, the specific surface area which is about 1.5 times as large as that of niobium powder containing no zirconium is obtained by adding zirconium. Can be kept.

Further, the niobium powder containing zirconium does not have a specific increase in LC value even when a high-capacity sintered body is produced by reducing the average particle size. Details of the reason are unknown, but are presumed as follows. Niobium has a large bonding force with the oxygen element,
Oxygen in the electrolytic oxide film easily diffuses into the niobium metal side. However, in the sintered body of the present invention, oxygen in the electrolytic oxide film is less likely to be bonded to the niobium metal inside the sintered body because of the interaction such as the intrinsic zirconium bonding with niobium, and the The diffusion of oxygen is suppressed, and as a result, the stability of the electrolytic oxide film can be maintained.
It is considered that the effect of reducing the variation and reducing the variation can be obtained.

In the present invention, the content of zirconium in niobium powder for producing a sintered body is important,
It is preferably 15 atomic%, and particularly preferably 0.05 to 3 atomic% in view of the balance between the capacity of the produced capacitor and the leakage current value. If the content of zirconium is too low, it is impossible to suppress the above-mentioned property that oxygen in the electrolytic oxide film easily diffuses into the niobium metal side, and as a result, it is impossible to maintain the stability of the electrolytic oxide film And the effect of lowering the LC cannot be obtained. On the other hand, if it is too large, the niobium content in the zirconium-containing niobium powder decreases, and the capacity decreases.

The zirconium-containing niobium powder of the present invention used for producing a sintered body has an average particle size of 0.2 μm to 5 μm.
Is preferred. Zirconium-containing niobium powder having such an average particle size is, for example, niobium-zirconium alloy ingot, pellets, after grinding hydrides such as powder,
It can be produced by dehydrogenation. The average particle size of the zirconium-containing niobium powder can be adjusted to a desired range by appropriately changing the amount of hydrogenation of the niobium-zirconium alloy, the pulverizing time, the pulverizing device, and the like. Also, the zirconium-containing niobium powder obtained above may be mixed with other niobium powder having an average particle size of 0.2 μm or more and less than 5 μm containing no zirconium to adjust the zirconium content. Such niobium powder, for example, niobium ingots, pellets, a method of dehydrogenating after pulverizing a hydride of the powder, a method of pulverizing sodium reduced sodium fluoroniobate, an alkali metal niobium oxide, It can be obtained by a method of reducing with an alkaline earth metal, tantalum, niobium, aluminum, hydrogen, carbon or the like.

The zirconium-containing niobium powder of the present invention may be a mixture of niobium powder containing no zirconium and powder of a metal zirconium or zirconium compound. Here, the zirconium compound includes zirconium carbide, zirconium oxide (including stabilized zirconia), zirconium alkoxide, zirconium boride,
Zirconium nitride, zirconium sulfide, zirconium silicide, zirconium hydride, zirconium hydroxide, zirconium sulfate, zirconium silicate, zirconium halide, zirconium oxyhalide, zirconium oxyacetate, zirconium oxynitrate, and the like can be used alone or in combination of two kinds. You may use it combining the above.

The zirconium-containing niobium powder of the present invention can also be obtained by a method of reducing a mixture of niobium oxide and zirconium oxide with an alkali metal, an alkaline earth metal, tantalum, niobium, aluminum, hydrogen, carbon or the like. .

In the zirconium-containing niobium powder of the present invention, even if a part of the zirconium-containing niobium powder is bonded to at least one of nitrogen, carbon, boron and sulfur in order to further improve the leakage current value. Good. Nitrogen, carbon,
The zirconium-containing niobium nitride, the zirconium-containing niobium carbide, the zirconium-containing niobium boride, and the zirconium-containing niobium sulfide, which are a combination of boron and sulfur, may contain any one of them alone,
A combination of four or more species may be used.

The amount of the bond (sum of the contents of nitrogen, carbon, boron, and sulfur) varies depending on the shape of the zirconium-containing niobium powder, but is 50 to 200,000 ppm for a powder having an average particle size of about 0.2 to 5 μm. Preferably, 200 to 20
000 ppm. If it is less than 50 ppm, no improvement in the LC characteristics will be seen, and if it exceeds 200,000 ppm, the capacity characteristics will deteriorate, making it unsuitable as a capacitor.

The nitriding of the zirconium-containing niobium powder can be carried out by liquid nitriding, ionic nitriding, gas nitriding, or a combination thereof. Among them, gas nitriding is preferred because the apparatus is simple and the operation is easy. Gas nitriding is
It can be performed by leaving the zirconium-containing niobium powder in a nitrogen gas atmosphere. The temperature of the nitriding atmosphere is 2000 ° C. or less, and the standing time is within several hours, so that the desired nitriding amount of zirconium-containing niobium powder can be obtained. Processing at a high temperature can shorten the processing time.

The carbonization of the zirconium-containing niobium powder may be any of gas carbonization, solid phase carbonization, and liquid carbonization. For example, zirconium-containing niobium powder may be mixed with a carbon source such as a carbon material or an organic substance having carbon such as methane under reduced pressure.
What is necessary is just to leave at 000 degreeC or less for several minutes to several tens hours.

The boride of the zirconium-containing niobium powder may be gas boride or solid phase boride. For example,
The zirconium-containing niobium powder may be left under a reduced pressure at 2000 ° C. or lower for several minutes to several tens of hours together with a boron source of boron halide such as boron pellets or trifluoroboron.

The sulfuration of the zirconium-containing niobium powder may be any of gas sulfurization, ion sulfurization, and solid-phase sulfurization. For example, the method of gas sulfurization in a sulfur gas atmosphere is achieved by leaving the zirconium-containing niobium powder in a sulfur atmosphere. The temperature of the sulfurizing atmosphere is 2000
A zirconium-containing niobium powder having a desired sulfide content can be obtained at a temperature of not more than ° C and a standing time of within several tens of hours. Further, the processing time can be reduced by performing the processing at a higher temperature.

The zirconium-containing niobium powder for a capacitor for producing a sintered body may be obtained by granulating the above-described zirconium-containing niobium primary powder into an appropriate shape, or may be made of ungranulated zirconium after granulation. Niobium-containing powder or niobium powder may be mixed and used in an appropriate amount. As a granulation method, for example, a method in which ungranulated zirconium-containing niobium powder is left under a high vacuum, heated to an appropriate temperature, and then crushed,
A method in which a suitable binder such as camphor, polyacrylic acid, polymethyl acrylate, or polyvinyl alcohol is mixed with a solvent such as acetone, alcohols, acetates, or water, and ungranulated zirconium-containing niobium powder, followed by crushing. And the like.

The use of the granulated zirconium-containing niobium powder improves the press-formability when producing a sintered body. The average particle size of the granulated powder is preferably from 20 to 500 μm. If the average particle size of the granulated powder is 20 μm or less, partial blocking occurs, and the fluidity to the mold is poor. 500 μm
Above, the corners of the compact after pressure molding are easily chipped.
Further, by setting the average particle size of the granulated powder to 60 to 250 μm, after the pressure-molded body is sintered, the cathode agent for producing a capacitor is easily impregnated into the sintered body.

The zirconium-containing niobium sintered body for a capacitor of the present invention is manufactured by molding and sintering the above-described zirconium-containing niobium powder or granulated zirconium-containing niobium powder. The method for producing the sintered body is not particularly limited,
For example, after zirconium-containing niobium powder is pressure-formed into a predetermined shape, the pressure is set to 10 ² to 10 ⁻⁵ Pa for several minutes to several hours.
It is obtained by heating in the range of 00 to 2000 ° C, preferably 900 to 1500 ° C, and more preferably 900 to 1300 ° C.

Next, the manufacture of the capacitor element will be described. The capacitor of the present invention includes the above-described sintered body as one electrode, a dielectric formed on the surface of the sintered body, and the other electrode provided on the dielectric.
For example, a lead wire having an appropriate shape and length made of a valve metal such as niobium or tantalum is prepared, and when the niobium powder is sintered and pressed, a part of the lead wire is formed inside the compact. And is designed and assembled so that the lead wire becomes a lead for drawing out the sintered body.

As the dielectric of the capacitor, for example, a dielectric made of tantalum oxide, niobium oxide, a polymer substance, a ceramic compound or the like can be mentioned, and it is obtained by forming a zirconium-containing niobium sintered body in an electrolytic solution. The dielectric mainly composed of niobium oxide is preferred. The formation of a zirconium-containing niobium electrode in an electrolytic solution is usually performed using a protonic acid aqueous solution, for example, a 0.1% phosphoric acid aqueous solution, a sulfuric acid aqueous solution or a 1% acetic acid aqueous solution, an adipic acid aqueous solution, or the like. When a zirconium-containing niobium electrode is formed in an electrolytic solution to obtain a niobium oxide dielectric, the capacitor of the present invention becomes an electrolytic capacitor, and the zirconium-containing niobium electrode becomes an anode.

The other electrode of the capacitor of the present invention is not particularly limited. For example, at least one material (compound) selected from an electrolytic solution, an organic semiconductor and an inorganic semiconductor known in the aluminum electrolytic capacitor industry. Can be used.

Specific examples of the electrolytic solution include a mixed solution of dimethylformamide and ethylene glycol in which 5% by mass of isobutyltripropylammonium borotetrafluoride electrolyte is dissolved, and propylene carbonate in which 7% by mass of tetraethylammonium borotetrafluoride is dissolved. A mixed solution of ethylene glycol and the like can be mentioned.

Specific examples of the organic semiconductor include an organic semiconductor composed of a benzopyrroline tetramer and chloranil, an organic semiconductor composed mainly of tetrathiotetracene, an organic semiconductor composed mainly of tetracyanoquinodimethane, and the following general formula: (1) or (2)

Embedded image (Wherein, R ^{1 to} R ⁴ may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, and X represents oxygen R ⁵ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms only when X is a nitrogen atom, and R ¹ and R ² and R ³ and R ⁴ are bonded to each other. A repeating unit represented by 2)
Examples of the above-mentioned polymer include an organic semiconductor containing a conductive polymer doped with a dopant as a main component. Known dopants can be used without limitation as the dopant.

Examples of the polymer containing two or more repeating units represented by the formula (1) or (2) include, for example, polyaniline, polyoxyphenylene, polyphenylene sulfide, polythiophene, polyfuran, polypyrrole, polymethylpyrrole, and substitution thereof. Derivatives and copolymers are exemplified. However, polypyrrole, polythiophene and substituted derivatives thereof (for example, poly (3,4-ethylenedioxythiophene) and the like) are preferred. In the present specification, the phrase "contains a conductive polymer as a main component" means that a conductive polymer containing a component derived from an impurity in a raw material monomer of an organic semiconductor or the like may be included. That the molecule is a substantially active ingredient. "

As the dopant, a sulfoquinone-based dopant, an anthracene monosulfonic acid-based dopant and various other anion-based dopants can be used.
Further, an electron acceptor dopant such as NO ⁺ and NO ₂ ⁺ salts may be used.

Specific examples of the inorganic semiconductor include an inorganic semiconductor containing lead dioxide or manganese dioxide as a main component, and an inorganic semiconductor made of triiron tetroxide. Such a semiconductor can be used alone, but may be used in combination of two or more kinds.

As the above organic semiconductor and inorganic semiconductor,
If the conductivity is in the range of 10 ⁻² S · cm ⁻¹ to 10 ³ S · cm ⁻¹ , the impedance value of the manufactured capacitor can be further reduced, and the capacitance at a high frequency can be further increased. it can.

When the other electrode is solid, a conductor layer may be provided thereon to improve electrical contact with an external lead (for example, a lead frame). The conductor layer can be formed, for example, by solidifying a conductive paste, plating, metal deposition, forming a heat-resistant conductive resin film, or the like. As the conductive paste, a silver paste, a copper paste, an aluminum paste, a carbon paste, a nickel paste, and the like are preferable, but one or more of these may be used. When two or more kinds are used, they may be mixed or may be stacked as separate layers. After applying the conductive paste, leave it in the air or
Alternatively, heat to solidify. Examples of plating include nickel plating, copper plating, silver plating, and aluminum plating. Examples of the metal to be deposited include aluminum, nickel, copper, and silver.

Specifically, for example, a capacitor is formed by sequentially laminating a carbon paste and a silver paste on the other electrode and sealing with a material such as epoxy resin. The capacitor may have a niobium or tantalum lead sintered integrally with the zirconium-containing niobium sintered body or later welded.

The capacitor of the present invention having the above-described structure can be made into a capacitor product for various uses by, for example, a resin mold, a resin case, a metal outer case, resin dipping, and outer packaging with a laminated film.

When the other electrode is a liquid, the capacitor formed by the electrodes and the dielectric is housed in, for example, a can electrically connected to the other electrode to form a capacitor. In this case, the electrode side of the zirconium-containing niobium sintered body is designed so as to be led out to the outside through the above-mentioned niobium or tantalum lead, and to be insulated from the can by insulating rubber or the like.

[0044]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. The methods for measuring and evaluating the capacitance of the sintered body, the leakage current value, the capacitance of the chip-processed capacitor, and the leakage current value in each example are as follows.

(1) Capacity Measurement of Sintered Body At room temperature, an LCR measuring device manufactured by Hewlett-Packard Company was placed between a sintered body immersed in 30% sulfuric acid and an electrode of a tantalum material immersed in a sulfuric acid solution. 120H connected and measured
The capacity at z was taken as the capacity of the sintered body. (2) Leakage current measurement of sintered body At room temperature, 70% of the formation voltage at the time of forming a dielectric was placed between the sintered body immersed in a 20% phosphoric acid aqueous solution and an electrode placed in the phosphoric acid aqueous solution. The current value measured after the DC voltage of 14 V was continuously applied for 3 minutes was defined as the leakage current value (LC value) of the sintered body. (3) Measurement of Capacitance of Capacitor At room temperature, an LCR measuring device manufactured by Hewlett-Packard Company was connected between terminals of the manufactured chip, and the measurement was performed.
The capacity at Hz was taken as the capacity of the capacitor processed by the chip. (4) Measurement of leakage current of capacitor At room temperature, the rated voltage value (2.5 V, 4 V, 6.3)
V, 10 V, 16 V, 25 V, etc.) and a DC voltage (6.3) that is close to about 1/3 to about 1/4 of the formation voltage at the time of producing the dielectric.
The current value measured after the application of V) was continuously applied between the terminals of the chip for 1 minute was defined as the leakage current value of the capacitor processed into the chip.

Example 1: Sintering of zirconium-containing niobium powder
Use niobium ingot 92g and zirconium powder 1g
Zirconium containing 1 mol% zirconium by arc melting
U-containing niobium ingots were prepared. This ingot
50 g is put in a SUS304 reaction vessel,
Introduced hydrogen for 10 hours. After cooling, the hydrogenated di
SU containing ruconium-containing niobium lump in SUS ball
It was placed in a pot made of S304 and ground for 10 hours. Next, S
This hydride is added to a US304 wet grinder with water for 20 minutes.
Vol% slurry and zirconia ball
And wet-pulverized for 7 hours. Centrifuge this slurry.
Thereafter, the pulverized material was obtained by decantation. Crushed material
Vacuum dried under the condition of 133 Pa (1 Torr) and 50 ° C.
Was. Subsequently, the zirconium hydride-containing niobium powder was added to 1.3.
3 × 10^-2Pa (1 × 10^-FourTorr) Pa, 400 ° C
For 1 hour to dehydrogenate. Made with zirconium
The average particle size of the niobium powder is 1.0 μm, and zirconium
The content was measured by atomic absorption spectrometry.
Met. The zirconium-containing thus obtained
4 × 10 niobium powder^-3Pa (3 × 10 ^-FiveTorr) true
It granulated at 1000 degreeC under air. After that, the granulated mass is crushed
Thus, a granulated powder having an average particle size of 120 μm was obtained. Jill obtained
The niobium granulated powder containing conium is mixed with a 0.3 mmφ niobium wire.
Molded together, approximately 0.3 x 0.18 x 0.45 cm
A molded article (about 0.1 g) was produced. 4 × 1
0^-3Pa (3 × 10^-Five1200 ° C. under Torr vacuum
For 30 minutes to obtain a sintered body. The resulting baked
When the tensile strength of the niobium wire of the consolidation was measured, it was 3k
g / cm^Two(2.9 × 10^FivePa) and sufficient strength
Had. Subsequently, the sintered body is placed in a 0.1% phosphoric acid aqueous solution.
In a bath at a voltage of 20V for 200 minutes at a temperature of 80 ° C.
As a result, a dielectric layer was formed on the surface. After this,
Volume in 30% sulfuric acid and leakage in 20% aqueous phosphoric acid
The current (hereinafter abbreviated as “LC”) was measured. result
Are shown in Table 3.

Examples 2 to 15: Zirconium-containing niobium / tantalum powder sintered body Using zirconium powder and niobium ingot, tantalum ingot, or niobium-tantalum alloy ingot at any ratio, zirconium-containing niobium ingot, zirconium by arc melting. A tantalum containing ingot or a zirconium containing niobium-tantalum ingot was prepared. Using the same apparatus as in Example 1 for 50 g of this ingot, the pulverization time was adjusted to obtain zirconium-containing niobium powder, zirconium-containing tantalum powder, and zirconium-containing niobium-tantalum powder having desired particle diameters. Using each of these powders, a sintered body was prepared in the same manner as in Example 1, and the capacity and LC were measured. Table 3 shows the results.

Comparative Examples 1 to 6: Niobium powder, tantalum powder, niobium-tantalum alloy powder containing no zirconium By operating in the same manner as in Example 1, niobium powder containing no zirconium, tantalum powder, niobium-tantalum alloy powder Was prepared. A sintered body was prepared using this powder in the same manner as in Example 1, and the capacity and LC were measured. Table 3 shows the results.

Comparative Examples 7 and 8: Niobium powder containing excess zirconium By operating in the same manner as in Example 1, zirconium-containing niobium powder containing 18.7 mol% and 24.6 mol% of zirconium was prepared. Example 1 using this powder
A sintered body was prepared in the same manner as described above, and the capacity and LC were measured. Table 3 shows the results.

[0050]

[Table 3]

Examples 16 to 21: Zirconium-containing sintered niobium powder 100 g of niobium ingot was placed in a reaction vessel made of SUS304, and hydrogen was continuously introduced at 400 ° C. for 10 hours. After cooling, the hydrogenated niobium mass was placed in a SUS ball
It was placed in a US304 pot and ground for 10 hours. next,
SUS304 wet pulverizer (trade name "Attritor")
The hydride was slurried with water at 20 vol% and zirconia balls were charged and wet-pulverized for 7 hours. After centrifugal sedimentation of this slurry, decantation was performed to obtain a pulverized product. Grind the material to 133 Pa (1 Torr)
r), and vacuum dried at 50 ° C. Subsequently, the niobium hydride powder was added to 1.33 × 10 ⁻² Pa (1 × 10 ⁻⁴ Torr).
r), heated at 400 ° C. for 1 hour to dehydrogenate. The average particle size of the produced niobium powder was 1.3 μm. Any one of zirconium oxide, zirconium hydride, and zirconium metal having an average particle size of about 1 μm was mixed with the niobium powder at an arbitrary ratio. The obtained niobium powder containing zirconium powder was added to 4 × 10 ⁻³ Pa (3 × 10 ⁻⁵ Torr).
Under a vacuum of 1000 ° C. Thereafter, the granulated mass was crushed to obtain granulated powder having an average particle size of 190 μm. The obtained zirconium-containing niobium granulated powder is molded together with a 0.3 mmφ niobium wire to obtain a powder of about 0.3 × 0.18 × 0.45.
cm of a compact (about 0.1 g) was produced. Next, these compacts were left under a vacuum of 4 × 10 ⁻³ Pa (3 × 10 ⁻⁵ Torr) at 1230 ° C. for 30 minutes to obtain a sintered body. The obtained sintered body is placed in an aqueous 0.1% phosphoric acid solution for 8 hours.
A dielectric layer was formed on the surface by forming at a temperature of 0 ° C. for 200 minutes at a voltage of 20V. Thereafter, the volume in 30% sulfuric acid and the LC in 20% phosphoric acid aqueous solution were measured. Table 4 shows the results.

[0052]

[Table 4]

Examples 22 to 26: zirconium-containing partially niobium nitride powder sintered body 1.2% of zirconium produced by the same method as in Example 1.
10 g of zirconium-containing niobium powder having an average particle size of 0.9 μm containing mol% was placed in a SUS304 reaction vessel,
Nitrogen was continuously introduced at 0.5C for 0.5 to 20 hours to obtain zirconium-containing niobium nitride. The nitrogen amount of this nitride was determined using a nitrogen amount measuring device manufactured by LECO, which obtains the nitrogen amount from the thermal conductivity, and the ratio to the separately measured mass of the powder was defined as the nitriding amount. It was 89% by mass. The obtained zirconium-containing niobium nitride was granulated, molded and sintered in the same manner as in Example 1, and the obtained sintered body was 0.1%.
% Phosphoric acid aqueous solution at a temperature of 80 ° C. for 200 minutes for 20 minutes
A dielectric layer was formed on the surface by forming at a voltage of V. Thereafter, the volume in 30% sulfuric acid and the LC in 20% phosphoric acid aqueous solution were measured. Table 5 shows the results.

[0054]

[Table 5]

Examples 27 to 29: Zirconium-containing niobium powder / niobium powder mixture sintered body In a nickel crucible, 20 g of potassium fluoride niobate sufficiently vacuum-dried at 80 ° C., and sodium was added 10 times as much as potassium fluoride niobate. 1 mole under argon atmosphere
The reduction reaction was performed at 000 ° C. for 20 hours. After the reaction, the reaction mixture was cooled, the reduced product was washed with water, washed sequentially with 95% sulfuric acid and water, and dried in vacuum. Furthermore, after pulverizing for 40 hours using a ball mill of an alumina pot containing silica alumina balls, the pulverized material was immersed and stirred in a 3: 2 (mass ratio) mixed solution of 50% nitric acid and 10% hydrogen peroxide. Then p
The solution was sufficiently washed with water until H became 7 to remove impurities, and dried under vacuum. The average particle size of the produced niobium powder was 1.2 μm. The obtained niobium powder had an average particle size of 1.0 mol% containing 10 mol% of zirconium prepared in the same manner as in Example 14.
μm of zirconium-containing niobium powder was sufficiently mixed at an arbitrary ratio, and granulated, molded, and sintered in the same manner as in Example 14 to obtain a sintered body. The capacity, LC
Was respectively measured. Table 6 shows the results.

Examples 30 to 32: Niobium powder / niobium powder mixture sintered body partially containing zirconium nitride 50 g of niobium ingot was placed in a SUS304 reaction vessel, and hydrogen was continuously introduced at 400 ° C. for 12 hours. After cooling, the hydrogenated niobium mass is placed in an SUS with iron balls.
The mixture was put in a pot made of No. 304 and ground for 10 hours. Further, the pulverized product was placed in the above-mentioned SUS304 reactor and hydrogenated again under the above-mentioned conditions. Next, a 20 vol% slurry of this hydride and water and a zirconia ball were placed in a SUS304 wet pulverizer and wet pulverized for 6 hours. After centrifugal sedimentation of this slurry, decantation was performed to obtain a pulverized product. 1.33 × 1 crushed material
Vacuum drying was performed under the conditions of 0 ² Pa (1 Torr) and 50 ° C. Subsequently, the niobium hydride powder was added to 1.33 × 10 ⁻² Pa
(10 ⁻⁴ Torr), heated at 400 ° C. for 1 hour to dehydrogenate. The average particle size of the produced niobium powder was 1.0 μm. The obtained niobium powder had an average particle diameter of 0.9 μm containing 10 mol% of zirconium prepared in the same manner as in Example 14.
m and zirconium-containing niobium powder were sufficiently mixed at an arbitrary ratio, and a nitride was obtained in the same manner as in Example 24. Then, granulation, molding and sintering were performed to obtain a sintered body. The capacity and LC of this sintered body were measured. Table 6 shows the results.

[0057]

[Table 6]

Examples 33 to 34: Production and evaluation of capacitor element according to the present invention Example 33 is Example 1 and Example 34 is Example 11.
Fifty sintered bodies each obtained by the same method were prepared.
These sintered bodies were subjected to electrolytic formation at a voltage of 20 V using a 0.1% phosphoric acid aqueous solution for 200 minutes to form a dielectric oxide film on the surface. Next, immersion in a 60% manganese nitrate aqueous solution and subsequent heating at 220 ° C. for 30 minutes were repeated to form a manganese dioxide layer as the other electrode layer on the dielectric oxide film. A carbon layer and a silver paste layer were sequentially laminated thereon. Next, after mounting a lead frame, the whole was sealed with an epoxy resin to produce a chip capacitor.
Table 7 shows the average of the capacities and the LC values (n = 50 each) of this chip type capacitor.

Comparative Examples 8 to 10: Capacitor element using niobium powder sintered body containing no zirconium In a nickel crucible, sodium was added to 20 g of potassium fluoride niobate which was sufficiently vacuum-dried at 80 ° C. Double-molar amount is added, and 1
The reduction reaction was performed at 000 ° C. for 20 hours. After the reaction, the reaction mixture was cooled, the reduced product was washed with water, washed sequentially with 95% sulfuric acid and water, and dried in vacuum. Furthermore, after pulverizing for 40 hours using a ball mill of an alumina pot containing silica alumina balls, the pulverized material was immersed and stirred in a 3: 2 (mass ratio) mixed solution of 50% nitric acid and 10% hydrogen peroxide. Then p
The solution was sufficiently washed with water until H became 7 to remove impurities, and dried under vacuum. The average particle size of the produced niobium powder was 1.3 μm. 30 g of the niobium powder obtained in this way is SUS
The reactor was placed in a reaction vessel made of 304, and nitrogen was continuously introduced at 300 ° C. for 0.5 to 4 hours to obtain niobium nitride. The nitrogen amount of this nitride was determined using a nitrogen amount measuring device manufactured by LECO, which obtains the nitrogen amount from the thermal conductivity, and the ratio to the separately measured mass of the powder was defined as the nitriding amount. It was 30% by mass. This niobium nitride was subjected to granulation, molding and sintering in the same manner as in Example 1 to obtain a sintered body. Using the obtained sintered body, 50 chip-type capacitors were produced in the same manner as in Examples 33 to 34, and each physical property was measured. The results are shown in Table 7.

[0060]

[Table 7]

Examples 35 to 37: Preparation and evaluation of a capacitor element according to the present invention Example 35 is Example 7, Example 36 is Example 12,
In Example 37, 50 sintered bodies each obtained by the same method as in Example 24 were prepared. These sintered bodies were subjected to electrolytic formation at a voltage of 20 V using a 0.1% phosphoric acid aqueous solution for 200 minutes to form a dielectric oxide film on the surface. Next, an operation of contacting an equivalent mixture of a 10% aqueous solution of ammonium persulfate and a 0.5% aqueous solution of anthoraquinone sulfonic acid on the dielectric oxide film and then touching pyrrole vapor is performed at least five times. To form the other electrode made of polypyrrole. A carbon layer and a silver paste layer were sequentially laminated thereon. Next, after mounting a lead frame, the whole was sealed with an epoxy resin to produce a chip capacitor. Table 8 shows the average of the capacitance and the LC value of this chip type capacitor (n = 50 each).

Comparative Examples 11 to 13: Capacitor element of niobium powder sintered body containing no zirconium 50 g of niobium ingot was placed in a SUS304 reaction vessel, and hydrogen was continuously introduced at 400 ° C. for 12 hours. After cooling, the hydrogenated niobium mass is placed in an SUS with iron balls.
The mixture was put in a pot made of 304 and pulverized for 10 hours. Further, the pulverized product was placed in the above-mentioned SUS304 reactor and hydrogenated again under the above-mentioned conditions. Next, a 20 vol% slurry of this hydride and water and a zirconia ball were placed in a SUS304 wet pulverizer and wet pulverized for 6 hours. After centrifugal sedimentation of this slurry, decantation was performed to obtain a pulverized product. 1.33 × 1 crushed material
Vacuum drying was performed under the conditions of 0 ² Pa (1 Torr) and 50 ° C. Subsequently, the niobium hydride powder was added to 1.33 × 10 ⁻² Pa
(1 × 10 ⁻⁴ Torr) at 400 ° C. for 1 hour to dehydrogenate. The average particle size of the produced niobium powder was 1.0 μm. 30 g of niobium powder was placed in a SUS304 reaction vessel, and nitrogen was continuously introduced at 300 ° C. for 0.5 to 3 hours to obtain a niobium nitride. The nitrogen amount of this nitride was determined using a nitrogen amount meter manufactured by LECO, which determines the nitrogen amount from the thermal conductivity, and the ratio to the separately measured mass of the powder was defined as the nitriding amount. It was 28% by mass. This niobium nitride was subjected to granulation, molding and sintering in the same manner as in Example 1 to obtain a sintered body. Example 35 was prepared using the obtained sintered body.
50 chip capacitors were made in the same way as
Each physical property was measured. The results are also shown in Table 8.

[0063]

[Table 8]

Examples 38 to 39: Production and evaluation of a capacitor element according to the present invention Example 38 is Example 8, Example 39 is Example 15,
Fifty sintered bodies each obtained by the same method were prepared.
These sintered bodies were subjected to electrolytic formation at a voltage of 20 V using a 0.1% phosphoric acid aqueous solution for 200 minutes to form a dielectric oxide film on the surface. Next, after immersing in a 1: 1 (volume ratio) mixed solution of a 35% aqueous lead acetate solution and a 35% aqueous ammonium persulfate solution, the reaction was repeated at 40 ° C. for 1 hour, so that the other electrode layer was formed on the dielectric oxide film. A mixed layer of lead dioxide and lead sulfate was formed. A carbon layer and a silver paste layer were sequentially laminated thereon. Next, after placing the lead frame,
The whole was sealed with epoxy resin to produce a chip capacitor. Table 9 shows the average (n = 50 each) of the capacitance and the LC value of this chip-type capacitor.

[0065]

[Table 9]

[0066]

According to the present invention, the capacitor manufactured from the sintered body of the capacitor powder mainly containing niobium and / or tantalum containing a specific amount of zirconium has a leakage current (L
C) A large-capacity capacitor having good characteristics and little variation and high reliability.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H01G 9/04 301 H01G 9/02 331C 9/052 331G 9/04 9/05 KHF term (reference) 4G031 AA12 AA14 AA15 BA09 GA02 GA03 5E082 AA01 AA05 AB01 AB09 BC38 BC40 EE14 EE22 EE23 EE28 EE29 EE30 EE35 FG03 FG27 FG44 GG03 GG04 HH27 HH48 LL22 LL23 MM23 MM24 PP09 PP10

Claims (17)

[Claims] 1. A capacitor powder containing zirconium and containing niobium and / or tantalum as a main component. 2. The capacitor powder according to claim 1, containing 0.01 to 15 atomic% of zirconium and containing niobium and / or tantalum as a main component. 3. The method according to claim 1, wherein niobium is a main component.
The powder for capacitors according to 1. 4. The powder for a capacitor according to claim 1, comprising tantalum as a main component. 5. The powder for a capacitor according to claim 1, comprising a niobium-tantalum alloy as a main component. 6. The capacitor powder according to claim 1, having an average particle size of 0.2 μm to 5 μm. 7. The capacitor powder according to claim 1, having a specific surface area of 0.5 to 15 m ² / g. 8. The capacitor powder according to claim 1, wherein a part of niobium and / or tantalum is combined with at least one of nitrogen, carbon, boron and sulfur. 9. A capacitor powder having an average particle size of 20 to 500 μm, obtained by granulating the capacitor powder according to claim 1. 10. A sintered body using the powder for a capacitor according to claim 1. 11. The sintered body according to claim 10, having a specific surface area of 0.5 to ⁵ m ² / g. 12. The sintered body according to claim 10, wherein the electrode is one electrode, a dielectric formed on the surface of the sintered body, and the other electrode provided on the dielectric. Capacitors. 13. The capacitor according to claim 12, wherein the dielectric comprises niobium oxide and / or tantalum oxide. 14. The capacitor according to claim 13, wherein the niobium oxide and / or tantalum oxide is formed by electrolytic oxidation. 15. The capacitor according to claim 12, wherein the other electrode is at least one material selected from an electrolyte, an organic semiconductor, and an inorganic semiconductor. 16. The other electrode comprises an organic semiconductor, wherein the organic semiconductor comprises an organic semiconductor comprising benzopyrroline tetramer and chloranil, an organic semiconductor comprising tetrathiotetracene as a main component, and tetracyanoquinodimethane as a main component. Organic semiconductor, and the following general formula (1) or (2): (Wherein, R ^{1 to} R ⁴ may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, and X represents oxygen R ⁵ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms and is present only when X is a nitrogen atom, and R ¹ and R ² and R ³ and R ⁴ are bonded to each other. At least one organic semiconductor selected from the group consisting of organic semiconductors containing as a main component a conductive polymer obtained by doping a polymer containing two or more repeating units represented by the following formula: The capacitor of claim 15. 17. The capacitor according to claim 16, wherein the organic semiconductor is at least one selected from polypyrrole, polythiophene, and substituted derivatives thereof.