JP2002025864A - Niobium powder for capacitor, sintered compact using the same and capacitor using the compact - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a niobium sintered compact, containing antimony for a capacitor exhibiting a small relative leakage current, niobium powder containing antimony used for it and a capacitor which uses the powder. SOLUTION: Niobium powder, containing antimony which preferably has an antimony content of 0.1-10 mol% and whose mean particle diameter is preferably 0.2-5 μm, is used. The sintered compact and the capacitor are made up using the niobium powder containing antimony.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a niobium powder for a capacitor having a large capacity per unit mass and excellent in specific leakage current characteristics, a sintered body using the same, 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 this 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, so that the demand for miniaturization is not satisfied. On the other hand, in the method in which the specific surface area is increased by pulverizing the tantalum powder, the pore diameter of the tantalum sintered body is reduced, and the number of closed holes is increased in the sintering step, so that impregnation of the cathode agent in a later step becomes difficult. As one of the researches to solve these drawbacks, a capacitor of a powder sintered body using a material having a larger dielectric constant than tantalum can be considered. Materials having a large dielectric constant include niobium and titanium.

[0004] However, the sintered bodies produced from these materials have a large "specific leakage current value" and are not satisfactory. Since niobium and titanium alone have a large dielectric constant, it is possible to obtain a large-capacity capacitor,
A small “specific leakage current value” is an important condition for obtaining a capacitor having good reliability. By evaluating the leakage current value per capacity, that is, the “specific leakage current value”, it is possible to evaluate whether a large capacity can be obtained in a state where the leakage current value is not more than a practicable leakage current value.

[0005] Here, in the case where a dielectric layer is formed on the surface of a sintered body by electrolytic oxidation, a formation voltage of 70% is obtained at room temperature.
% Is defined as the specific leakage current value obtained by dividing the leakage current value when the% voltage is continuously applied for 3 minutes by using the product of the formation voltage and the capacity during the electrolytic oxidation. That is, specific leakage current value = (LC / (C × V)) (where, LC: leakage current value, C: capacity, V: formation voltage)
Is defined.

In the case of a sintered body using tantalum powder, for example, “CAPACITOR GR” manufactured by Showa Cabot Super Metal Co., Ltd.
The specific leakage current value is calculated from the capacitance and leakage current value described in the catalog of “ADE TANTALUM”, and is 1500 pA / (μF · V).
It is said that the actual measured value of the specific leakage current value that guarantees it is generally 1/3 to 1/4 or less in the catalog, and a preferable value is 400 pA / (μF · V) or less.

However, in a conventional sintered capacitor using niobium powder using only niobium or titanium powder,
The specific leakage current value is large and exceeds this value, and the capacitor has no reliability and has not been put to practical use.

Japanese Patent Application Laid-Open No. 55-157226 discloses that a compacted niobium powder having a particle size of 2 μm or less is compacted from a coagulated powder and sintered, and the molded sintered body is cut into small pieces. A method for manufacturing a sintered element for a capacitor in which the lead portions are joined and then sintered again is disclosed. However, the publication does not disclose niobium powder containing antimony nor the characteristics of the capacitor.

US Pat. No. 4,084,965 discloses a capacitor using hydrogenated pulverized niobium ingot to obtain 5.1 μm niobium powder. Niobium powder containing antimony is also disclosed in US Pat. No. 4,084,965. No characteristics are disclosed. Japanese Patent Application Laid-Open No. H10-242004 discloses that the leakage current value is improved by, for example, nitriding a part of niobium. However, niobium powder containing antimony also discloses the capacitor characteristics. Absent.

[0010]

DISCLOSURE OF THE INVENTION The present invention relates to a niobium powder for a capacitor capable of providing a capacitor having a large capacity per unit mass and a small specific 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 used capacitor.

[0011]

Means for Solving the Problems The present inventors diligently studied and completed the following invention. That is, the present invention includes the following inventions. (1) Niobium powder for capacitors containing antimony. (2) The niobium powder for a capacitor according to claim 1, wherein the content of antimony is 0.1 to 10 mol%. (3) The niobium powder for a capacitor according to the above (1) or (2), wherein the average particle size is 0.2 μm or more and less than 5 μm. (4) The capacitor as described in any one of (1) to (3) above, wherein the niobium powder contains at least one selected from the group consisting of niobium nitride, niobium carbide, niobium boride, and niobium sulfide. For niobium powder.

(5) A sintered body using the niobium powder described in any one of (1) to (4) above. (6) The sintered body according to the above (5), having a specific leakage current value of 400 pA / (μF · V) or less. (7) A capacitor comprising the sintered body described in (6) as one electrode, a dielectric formed on the surface thereof, and the other electrode. (8) The capacitor according to the above item 7, wherein the dielectric contains niobium oxide.

(9) The capacitor as described in (8) above, wherein the niobium oxide is formed by electrolytic oxidation. (10) The capacitor according to the above item 7, wherein the other electrode is at least one material (compound) selected from an electrolytic solution, an organic semiconductor, and an inorganic semiconductor. (11) The other electrode is composed of an organic semiconductor, the organic semiconductor is composed of benzopyrroline tetramer and chloranil, an organic semiconductor composed mainly of tetrathiotetracene, and a tetracyanoquinodimethane composed mainly of tetracyanoquinodimethane. An organic semiconductor, and the following general formula (1) or (2)

[0014]

Embedded image (Wherein, R ^{1 to} R ⁴ represent hydrogen, an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, which may be the same or different, X is oxygen, R ⁵ represents a hydrogen or an alkyl group having 1 to 6 carbon atoms and is present only when X is a nitrogen atom; R ¹ and R ² and R ³ and R ⁴ are bonded to each other to form a ring; Wherein at least one kind of organic semiconductor selected from the group consisting of organic semiconductors containing a conductive polymer as a main component obtained by doping a polymer containing two or more repeating units represented by the following formula: 8. The capacitor according to 7. (12) The capacitor according to the above item 10, wherein the organic semiconductor is at least one selected from polypyrrole, polythiophene, and substituted derivatives thereof.

[0015]

DETAILED DESCRIPTION OF THE INVENTION In accordance with the present invention, the capacitance of a capacitor is generally given by: Capacity C = ε × (S / d) (C: capacity, ε: permittivity,
S: specific area, d = distance between electrodes Here, since d = k × V, (k: constant, V: formation voltage), C = ε × (S / (k × V)), and C ×
V = (ε / k) × S At this time, the specific leakage current value =
When defined as (LC / (C × V)) and (LC: leakage current value), the specific leakage current value = (LC / (C × V)) = (LC / ((ε /
k) × S)).

From the above equation, to decrease the specific leakage current value, one of a method of decreasing LC, a method of increasing (C × V), a method of increasing ε, and a method of increasing S, etc. It is thought that this can be achieved by selecting. In the present invention, the specific surface area of the powder can be increased by setting the average particle size of the antimony-containing niobium powder for forming the sintered body to less than 5 μm. As a result, CV
Is increased, and the specific leakage current value can be reduced.

However, when the average particle size of the antimony-containing niobium powder is less than 0.2 μm, impregnation of the cathode agent becomes difficult when a sintered body is prepared from the powder as described above. Therefore, the capacity cannot be increased as a result, which is not suitable for practical use. From the above points, the antimony-containing niobium powder of the present invention has an average particle size of 0.2 μm to 5 μm.
Since the value is less than the specific leakage current value, it can be set to a region where the specific leakage current value becomes small.

On the other hand, it is known that the dielectric constant (ε) of niobium is about twice as large as that of tantalum, but it is not known whether antimony is a valve metal. Therefore, it is unclear whether ε increases by adding antimony to niobium.

On the other hand, since niobium has a larger bonding force with an oxygen element than tantalum, oxygen in the electrolytic oxide film is easily diffused into the niobium metal inside. However,
In the sintered body according to the present invention, since a part of niobium is bonded to antimony, oxygen in the electrolytic oxide film is hardly bonded to the niobium metal inside, and diffusion to the metal side is suppressed. As a result, it is presumed that the stability of the electrolytic oxide film can be maintained, and an effect of reducing LC can be obtained.

The sintered body obtained by the present invention has a good specific leakage current value as described above, and the preferable value is 400 p.
A / (μF · V) or less is shown. Further, in the present invention, by optimizing the antimony content and the average particle size of the antimony-containing niobium powder, the specific leakage current value can be reduced to 300.
It is also possible to make it pA / (μF · V) or less.

An embodiment for obtaining the sintered body of the present invention will be described. The antimony content in the antimony-containing niobium powder used for producing a sintered body is important. If the content of antimony 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 inside, 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 the content is too large, the niobium content in the antimony-containing niobium powder decreases, and the capacity decreases. Therefore, the amount of antimony in the antimony-containing niobium powder is preferably 0.1 to 10 mol%. Also, from the viewpoint of further reducing the specific leakage current value, 0.3 to 3 mol% is particularly preferable.

The antimony-containing niobium powder used for producing the sintered body has an average particle size of 0.2 μm or more and 5 μm.
m. When the average particle size is less than 0.2 μm, when forming a sintered body from the powder to form a capacitor,
Since the pores inside the sintered body are too small, it becomes difficult to impregnate a cathode material described later. If the average particle size is 5 μm or more, it is difficult to produce a desirable specific leakage current value. This is because the rate of change of capacity and the rate of change of leakage current with respect to the average particle size are different. Therefore, the average particle size is preferably 0.2 μm or more and less than 5 μm. From the point of making the specific leakage current value smaller, 2 μm
Less than is particularly preferred.

The average particle size used with the present invention, since the particle size distribution measuring instrument (trade name "Microtrac") measured D ₅₀ value using (particle size value cumulative mass% is 50 mass%) is there. Antimony-containing niobium powder having such an average particle size is, for example, a niobium-antimony alloy ingot,
Pellet, method by grinding and dehydrogenation of hydride of powder,
It can be obtained by a method or the like by carbon reduction of a mixture of niobium oxide and antimony oxide. For example, in the case of a method obtained by grinding and dehydrogenating a hydride of a niobium-antimony alloy ingot, an antimony having a desired average particle size is prepared by preparing a hydrogenation amount and a grinding time of the niobium-antimony alloy, a grinding device, and the like. A niobium-containing powder can be obtained.

The antimony-containing niobium powder thus obtained may be mixed with niobium powder having an average particle size of 0.2 μm or more and less than 5 μm. This niobium powder can be obtained by, for example, a method by pulverizing sodium reduced product of potassium fluoroniobate, a method by pulverizing and dehydrogenating a hydride of niobium ingot, a method by carbon reduction of niobium oxide, and the like.

In order to further improve the leakage current value of the antimony-containing niobium powder thus obtained, a part of the antimony-containing niobium powder is bonded to at least one of nitrogen, carbon, boron and sulfur. There may be. nitrogen,
Carbon, boron, antimony-containing niobium nitride, antimony-containing niobium carbide, antimony-containing niobium boride, antimony-containing niobium sulfide, which is a bond of sulfur, may contain any of these, and two or three of these, A combination of four types may be used.

The amount of the bond, ie, nitrogen, carbon, boron,
The sum of the sulfur contents varies depending on the shape of the antimony-containing niobium powder, but is 50 to 200,000 ppm, preferably 200 to 200 ppm in a powder having an average particle size of about 0.2 to 5 μm.
0000 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 treatment of the antimony-containing niobium powder can be carried out by any one of a liquid nitriding method, an ion nitriding method, a gas nitriding method and the like, or a combination thereof. Of these, the gas nitriding method of niobium powder performed in a nitrogen gas atmosphere is preferable because the apparatus is simple and the operation is easy. For example, this gas nitriding method is achieved by leaving the antimony-containing niobium powder in a nitrogen atmosphere.

The temperature of the nitriding atmosphere is 2000 ° C. or less, and the standing time is within several tens of hours, so that antimony-containing niobium powder having a desired nitrogen content can be obtained. Further, by performing this processing at a high temperature, the processing time can be reduced. The carbonization of the antimony-containing niobium powder may be any of a gas carbonization method, a solid phase carbonization method, and a liquid carbonization method. For example, an antimony-containing niobium powder is mixed with a carbon material or a carbon source such as an organic substance having carbon such as methane under reduced pressure for 20 minutes.
What is necessary is just to leave at 00 degreeC or less for several minutes to several tens hours.

The boriding of the antimony-containing niobium powder may be any of a gas boriding method and a solid phase boriding method. For example, the antimony-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 antimony-containing niobium powder may be any of a gas sulfurization method, an ion sulfurization method, and a solid phase sulfurization method. For example, the gas sulfurization method using a sulfur gas atmosphere is achieved by leaving the antimony-containing niobium powder in a sulfur atmosphere. The temperature of the sulfurizing atmosphere is 200
The antimony-containing niobium powder having the desired sulfide content can be obtained at 0 ° C. or lower and the standing time is within several tens of hours. Further, by performing this processing at a high temperature, the processing time can be reduced.

The antimony-containing niobium powder for a capacitor of the present invention may be used after granulating the above-mentioned antimony-containing niobium powder into a suitable shape, or after granulation, mixing an appropriate amount of ungranulated niobium powder. May be used. As the granulation method, a conventionally known method can be adopted. For example, a method in which ungranulated antimony-containing niobium powder is left under a high vacuum and then crushed after heating to a predetermined temperature, camphor, polyacrylic acid,
A method of mixing a binder such as polymethyl acrylate and an ungranulated antimony-containing niobium powder and then crushing the mixture is exemplified.

The antimony-containing niobium sintered body for a capacitor of the present invention is manufactured by sintering the above-described antimony-containing niobium powder. An example of a method for manufacturing a sintered body will be described below.
However, the method for producing a sintered body of the present invention is not limited to this example. For example, after pressure-molding antimony-containing niobium powder into a predetermined shape, 1-10 ^-7 Torr ((1
10 ⁻⁷ ) × 133 Pa), several minutes to several hours, 500 to 2
The heating may be performed at a temperature in the range of 000 ° C, preferably 900 ° C to 1500 ° C, and more preferably 900 ° C to 1250 ° C.

Next, the manufacture of the capacitor element will be described. For example, a lead wire made of a valve metal such as niobium or tantalum or the like and having an appropriate shape and length is prepared, and a part of the lead wire is formed inside the molded body at the time of press-molding the niobium powder described above. The lead wire is integrally molded so as to be inserted, and the lead wire is assembled and designed so as to serve as a lead of the sintered body.

A capacitor can be manufactured from the above-described sintered body as one electrode and a dielectric interposed between the other electrodes. Here, a dielectric mainly composed of niobium oxide is preferably used as the dielectric of the capacitor. For example, a dielectric mainly composed of niobium oxide can be easily obtained by forming an antimony-containing niobium sintered body as one electrode in an electrolytic solution. To form an antimony-containing niobium electrode in an electrolytic solution, a protonic acid aqueous solution is usually used.
For example, the reaction is performed using a 0.1% phosphoric acid aqueous solution, sulfuric acid, 1% acetic acid, adipic acid, or the like. When forming an antimony-containing niobium electrode in an electrolytic solution to obtain a niobium oxide dielectric, the capacitor of the present invention becomes an electrolytic capacitor,
The antimony-containing niobium electrode becomes the 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. ). 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 a mixture of propylene carbonate and ethylene glycol in which 7% by mass of tetraethylammonium borotetrafluoride is dissolved. A mixed solution is exemplified.

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)

[0037]

Embedded image (Wherein, R ^{1 to} R ⁴ represent hydrogen, an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, which may be the same or different, X is oxygen, R ⁵ represents a hydrogen or an alkyl group having 1 to 6 carbon atoms and is present only when X is a nitrogen atom; R ¹ and R ² and R ³ and R ⁴ are bonded to each other to form a ring; The polymer containing two or more repeating units represented by the formula (1) may be 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.

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 semiconductors may be used alone or in combination of two or more. In the present specification, the “main component” refers to a state in which the specific component contains 50% by mass or more, preferably 80% by mass or more.

Examples of the polymer containing two or more repeating units represented by the formula (1) or (2) include, for example, polyaniline, polyoxyphenylene, poniphenylene sulfide, polythiophene, polyfuran, polypyrrole, polymethylpyrrole, and polymethylpyrrole. Examples include substituted derivatives and copolymers. Among them, polypyrrole, polythiophene and substituted derivatives thereof (for example, poly (3,4-ethylenedioxythiophene) and the like) are preferable.

When the organic semiconductor and the inorganic semiconductor having a conductivity in the range of 10 ⁻² S · cm ⁻¹ to 10 ³ S · cm ⁻¹ are used, the impedance value of the manufactured capacitor becomes smaller, and the frequency of the capacitor becomes higher. Can be further increased. Further, when the other electrode is solid, a conductor layer may be provided thereon in order to improve the 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, depositing metal, 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, or the like is 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, it is left in the air or heated to be solidified. Examples of the plating include nickel plating, copper plating, silver plating, and aluminum plating. Examples of the metal to be deposited include aluminum, nickel, copper, and silver.

More specifically, for example, a capacitor is formed by sequentially laminating an aluminum paste and a silver paste on the second electrode and sealing with a material such as epoxy resin. The capacitor may have a niobium or tantalum lead that is integrally molded with the niobium sintered body or later welded.

The capacitor of the present invention having the above-described structure can be formed into a capacitor product for various uses by, for example, a resin mold, a resin case, a metal outer case, resin dipping, and an outer case made of a laminate film. it can. When the other electrode is liquid,
The capacitor composed of the two 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 antimony-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.

By manufacturing a sintered body using the niobium powder manufactured according to the present invention described above and manufacturing a capacitor from the sintered body, a capacitor with good reliability can be obtained.

[0045]

EXAMPLES Examples of the present invention will be specifically described below, but the present invention is not limited to these examples.

The capacity and leakage current value of the sintered body in this example were measured as follows. (Measurement of capacity of sintered body) At room temperature, an LCR measuring instrument made by HP (LCR made by Hewlett Packard) is placed between a sintered body immersed in 30% sulfuric acid and a tantalum material electrode put in a sulfuric acid solution. 120Hz measured by connecting a meter
The capacity in (Hertz) was taken as the capacity of the sintered body.

(Measurement of leakage current of sintered body)
The formation voltage between the sintered body immersed in a 20% phosphoric acid aqueous solution and the electrode immersed in the phosphoric acid aqueous solution is 7
The current value measured after continuously applying the DC voltage of 0% for 3 minutes was defined as the leakage current value (LC value) of the sintered body. In the present invention, a voltage of 14 V was applied.

The capacitance and leakage current of the chip-processed capacitor in this example were measured as follows. (Capacitance of Capacitor) At room temperature, an LCR measuring device manufactured by HP was connected between the terminals of the fabricated chip, and the capacitance at 120 Hz was taken as the capacitance of the chip-processed capacitor. (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.) of about 1/3 to about 1 /
A current value measured after a DC voltage close to 4 was continuously applied between terminals of the manufactured chip for one minute was defined as a leakage current value of the capacitor processed into the chip. In the present invention, a voltage of 6.3 V was applied.

(Example 1) 98.6 g of niobium ingot
And 1.4 g of antimony powder, an antimony-containing niobium ingot containing 1.1 mol% of antimony was produced by arc melting. 50g of this ingot is SUS304
And the hydrogen was continuously introduced at 400 ° C. for 10 hours. After cooling, the hydrogenated antimony-containing niobium lump was placed in a SUS304 pot containing SUS balls and ground for 10 hours. Next, this hydride was added to a SUS304 wet pulverizer (trade name “Attritor”) with water for 2 hours.
A 0 vol% slurry and zirconia balls were charged and wet-ground for 7 hours. After the slurry was centrifugally settled, decantation was performed to obtain a pulverized product.

The pulverized material was vacuum-dried at 1 Torr (133 Pa) and 50 ° C. Subsequently, the niobium powder containing antimony hydride was charged to 10 ⁻⁴ Torr (1.33 × 10 ⁻² Pa), 400
The mixture was heated at 1 ° C. for 1 hour and dehydrogenated. The average particle size of the prepared antimony-containing niobium powder was 1.3 μm, and the antimony content was 1 mol% as measured by atomic absorption analysis. The antimony-containing niobium powder thus obtained was molded together with a 0.3 mmφ niobium wire to prepare a molded body (about 0.1 g) of about 0.3 cm × 0.18 cm × 0.45 cm.

Next, these molded bodies were made 3 × 10 ⁻⁵ Torr.
(3.99 × 10 ⁻³ Pa) under vacuum at 1200 ° C. for 30 minutes.
A sintered body was obtained by standing for a minute. The obtained sintered body is placed in a 0.1% phosphoric acid aqueous solution at a temperature of 80 ° C. for 200 hours.
A dielectric layer was formed on the surface by forming for 20 minutes at a voltage of 20V. This is followed by a volume in 30% sulfuric acid, 2
The leakage current (hereinafter abbreviated as “LC”) in a 0% phosphoric acid aqueous solution was measured. Table 1 shows the results.

(Examples 2 to 6-1) In order to change the antimony content of the antimony-containing niobium powder, an arc melting process is performed. The amount of antimony is changed to 0.1 to 15 mol% by changing the amount of niobium and antimony. An antimony-containing niobium ingot was produced. Hereinafter, about 50 g of antimony-containing niobium ingot having each antimony concentration,
A sintered body was prepared in the same manner as in Example 1, and the capacity and LC were measured. Table 1 shows the results.

(Comparative Example 1, Examples 6-2, 6-3)
For comparison with 6-1, 0 mol% of antimony, 0.04%
Antimony-containing niobium ingots containing 1 mol% and 19.3 mol% were prepared. Hereinafter, about 50 g of the antimony-containing niobium ingot having each antimony concentration, a sintered body was produced by the same operation as in Examples 2 to 6-1, and the capacity and L
C was measured respectively. Table 1 shows the results.

(Examples 7 to 11-1) In order to change the average particle size of antimony-containing niobium powder, an antimony hydride-containing niobium lump containing 1.2 mol% of antimony prepared in the same manner as in Example 1 was used. It was placed in a SUS304 pot containing iron balls and ground for 10 hours. In addition, SUS30
This hydride was slurried with water at 20 vol% and zirconia balls were placed in a wet pulverizer (trade name: "Atritor") manufactured by No. 4 and wet pulverized by changing the time. After the slurry was centrifugally settled, decantation was performed to obtain a pulverized product. 1 Torr (133 Pa)
Vacuum drying was performed at 50 ° C.

Subsequently, the antimony-containing niobium powder was heated at 400 ° C. for 1 hour at 10 ⁻⁴ Torr (1.33 × 10 ⁻² Pa) and dehydrogenated to obtain antimony-containing niobium powder.
The average particle size of the antimony-containing niobium powder thus obtained was 0.2 to 5.1 μm. Further, the thus obtained antimony-containing niobium powder was 0.3 mmφ in diameter.
About 0.3cm x 0.18
A molded body (about 0.1 g) of cm × 0.45 cm was prepared. Next, these moldings were placed in a 2 × 10 ⁻⁵ Torr (2 × 10 ⁻⁵ Torr)
⁽⁻⁵ × 133 Pa) under vacuum at 1200 ° C. for 30 minutes to obtain a sintered body. The capacity and LC of the obtained sintered body were measured in the same manner as in Example 1. Table 2 shows the results.

(Examples 11-2 and 11-3) For comparison with Examples 7 to 11-1, an antimony hydride-containing niobium powder containing 1.2 mol% of antimony was used. The same operation was performed, and the average particle diameter was 8.8 μm and 22 μm.
Of antimony-containing niobium powder containing 1.2 mol% of antimony, a sintered body was prepared, and the capacity and LC were measured. Table 2 shows the results.

Examples 12 to 15 Nio Containing Antimony
As in Example 1 to change the sintering temperature of the sintered body
Grain containing 1.1 mol% of antimony prepared by a simple method
0.3mmφ antimony-containing niobium powder with a diameter of 1.2μm
About 0.3cm x 0.18
Make a molded body (about 0.1g) of cm × 0.45cm
Was. Next, these molded bodies were converted into 6 × 10^-6Torr (6 × 10
^-6× 133 Pa) to 5 × 10^-FiveTorr (5 × 10 ^-Five× 13
3Pa) under vacuum of 1100 ° C to 1300 ° C for 30 minutes
Various sintered bodies were obtained by allowing to stand for 100 minutes. Get
The sintered body thus obtained was subjected to the same method as in Example 1 to determine the capacity and LC.
Each was measured. Table 3 shows the results.

(Examples 16 to 20) In order to obtain antimony-containing niobium nitride, 10 g of antimony-containing niobium powder having an average particle diameter of 1.4 μm and containing 1.2 mol% of antimony prepared in the same manner as in Example 1. Was placed in a SUS304 reaction vessel, and nitrogen was continuously introduced at 300 ° C. for 0.5 to 20 hours to obtain antimony-containing niobium nitride. The nitrogen amount of this nitride was determined using a nitrogen amount measuring device 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 nitrogen content. 88
% By mass. The antimony-containing niobium nitride thus obtained was molded and sintered in the same manner as in Example 1, and the obtained sintered body was treated in a 0.1% phosphoric acid aqueous solution with 80%
A dielectric layer was formed on the surface by forming at a temperature of 200C for 200 minutes at a voltage of 20V. Thereafter, the volume in 30% sulfuric acid and the LC in 20% aqueous phosphoric acid were measured. Table 4 shows the results.

[0059]

[Table 1]

[0060]

[Table 2]

[0061]

[Table 3]

[0062]

[Table 4]

(Examples 21 to 24) In order to obtain a sintered body composed of a mixture of antimony-containing niobium powder and niobium powder, the same method as in Example 1 was used to contain 10 mol% of antimony and to have an average particle diameter of 2.4 μm. An antimony-containing niobium powder was obtained. Separately, in a nickel crucible, 20 g of potassium fluoride niobate sufficiently dried in vacuum at 80 ° C. is charged with 10-fold molar amount of sodium and potassium fluoride niobate, and reduced at 1000 ° C. for 20 hours in an argon atmosphere. The reaction was performed. After the reaction, the reaction mixture was cooled, and the reduced product was washed with water, washed sequentially with 95% sulfuric acid and water, and then dried under vacuum. Further, using an alumina pot ball mill containing silica alumina balls,
After crushing for 0 hour, the crushed product was immersed and stirred in a 3: 2 (mass ratio) mixed solution of 50% nitric acid and 10% hydrogen peroxide.

After that, impurities were removed by sufficiently washing with water until the pH became 7, followed by vacuum drying. The average particle size of the produced niobium powder was 2.6 μm. Obtained in this way,
Antimony-containing niobium powder and niobium powder were sufficiently mixed at an arbitrary ratio, molded and sintered in the same manner as in Example 1 to obtain a sintered body, and the capacity and LC of the sintered body were measured. did. Table 5 shows the results.

(Examples 25 to 28) In order to obtain a sintered body of antimony-containing niobium nitride comprising a mixture of antimony-containing niobium powder and niobium powder, an antimony-containing niobium nitride containing 10 mol% of antimony was obtained in the same manner as in Example 1. An antimony-containing niobium powder having a particle size of 1.2 μm was obtained. Separately, 50 g of niobium ingot was placed in a SUS304 reaction vessel, and
Hydrogen introduction was continued at 0 ° C. for 12 hours. After cooling, the hydrogenated niobium mass was placed in a SUS304 pot containing iron balls and ground for 10 hours. Further, this pulverized product was placed in the above-mentioned SUS304 reactor, and hydrogenated again under the above-mentioned conditions.

Next, this hydride was added to a SUS304 wet pulverizer (trade name “Attritor”) with water at 20 vol.
% Slurry and zirconia balls
Wet milled for hours. After the slurry was centrifugally settled, decantation was performed to obtain a pulverized product. 1 Torr of crushed material
(133 Pa), and vacuum dried at 50 ° C. Subsequently, the niobium hydride powder was reduced to 10 ^-4 Torr (1.33 × 10 ^-2 P
a), heated at 400 ° C. for 1 hour to dehydrogenate. The average particle size of the produced niobium powder was 1.3 μm. The antimony-containing niobium powder and the niobium powder obtained in this manner are sufficiently mixed at an arbitrary ratio, and a nitride is obtained in the same manner as in Examples 16 to 20, then molded and sintered to perform firing. A sintered body was obtained, and the capacity and LC of this sintered body were measured. Table 6 shows the results.

[0067]

[Table 5]

[0068]

[Table 6]

(Examples 29 to 35) Example 29 is Example 1, Example 30 is Example 5 and Example 31 is Example 7.
Example 32 is Example 13 and Example 33 is Example 1.
8, Example 34, Example 23, Example 35, and Example 28, 50 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. Then, on top of that, a carbon layer,
Silver paste layers were sequentially laminated. Next, after mounting a lead frame, the whole was sealed with epoxy resin to produce a chip-type capacitor. The capacitance of this chip type capacitor and L
Table 7 shows the average of the C values (n = 50 each). The LC value is a value when 6.3 V is applied at room temperature for 1 minute.

[0070]

[Table 7]

(Embodiments 36 to 42) Embodiment 36 is Embodiment 2, Embodiment 37 is Embodiment 6-1, Embodiment 38 is Embodiment 8, Embodiment 39 is Embodiment 15, and Embodiment 36 is Embodiment 2. Reference numeral 40 denotes Example 19, Example 41 denotes Example 21, and Example 42 denotes Example 26. Fifty sintered bodies were prepared by the same method. These sintered bodies were subjected to 0.1%
Electrolysis was performed for 200 minutes using a phosphoric acid aqueous solution to form a dielectric oxide film on the surface. Next, a 1: 1 (volume ratio) of 35% aqueous lead acetate and 35% aqueous ammonium persulfate was used.
After dipping in the mixed solution, the reaction was repeated at 40 ° C. for 1 hour to form a mixed layer of lead dioxide and lead sulfate as the other electrode layer on the dielectric oxide film. Continue on that,
A carbon layer and a silver paste layer were sequentially laminated. Next, after placing the lead frame, seal the whole with epoxy resin,
A chip-type capacitor was manufactured. Table 8 shows the average of the capacitance and the LC value of this chip type capacitor (n = 50 each). The LC value is a value when 6.3 V is applied at room temperature for 1 minute.

[0072]

[Table 8]

[0073]

The sintered body using the antimony-containing niobium powder of the present invention has a good specific leakage current value, and the capacitor made from the sintered body has a small LC value and is a highly reliable capacitor. .

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) C08G 75/02 C22C 1/04 E C22C 1/04 1/05 E 1/05 27/02 102Z 27/02 102 32/00 L 32/00 H01G 9/05 K F term (reference) 4J005 AA23 4J030 BA03 BF13 BG08 BG10 CA01 4J032 BA02 BA03 BA04 BA12 BA13 BA14 BB01 BD02 4J043 PA01 QB02 RA08 UA121 YB05 ZA45 ZB47 4K018 AA04 AB02 AB08 BA11 BA20 BB04 BD10 DA11 KA39

Claims (12)

[Claims] 1. A niobium powder for a capacitor containing antimony. 2. The niobium powder for a capacitor according to claim 1, wherein the content of antimony is 0.1 to 10 mol%. 3. The niobium powder for a capacitor according to claim 1, wherein the average particle size is 0.2 μm or more and less than 5 μm. 4. The method according to claim 1, wherein the niobium powder contains at least one selected from the group consisting of niobium nitride, niobium carbide, niobium boride, and niobium sulfide. The described niobium powder for a capacitor. 5. A sintered body using the niobium powder according to any one of claims 1 to 4. 6. The sintered body according to claim 5, which has a specific leakage current value of 400 pA / (μF · V) or less. 7. A capacitor comprising the sintered body according to claim 6 as one electrode, a dielectric formed on the surface thereof, and the other electrode. 8. The capacitor according to claim 7, wherein the dielectric contains niobium oxide. 9. The capacitor according to claim 8, wherein the niobium oxide is formed by electrolytic oxidation. 10. The capacitor according to claim 7, wherein the other electrode is at least one material (compound) selected from an electrolyte, an organic semiconductor, and an inorganic semiconductor. 11. 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. And an organic semiconductor represented by the following general formula (1) or (2): (Wherein, R ^{1 to} R ⁴ represent hydrogen, an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, which may be the same or different, X is oxygen, R ⁵ represents a hydrogen or an alkyl group having 1 to 6 carbon atoms and is present only when X is a nitrogen atom; R ¹ and R ² and R ³ and R ⁴ are bonded to each other to form a ring; At least one organic semiconductor selected from the group consisting of organic semiconductors containing a conductive polymer as a main component obtained by doping a polymer containing two or more repeating units represented by the following formula: Item 8. The capacitor according to Item 7. 12. The capacitor according to claim 10, wherein the organic semiconductor is at least one selected from polypyrrole, polythiophene, and substituted derivatives thereof.