JP2002100542A - Powder for capacitor, sintered body using the powder, and capacitor using the sintered body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide powder for a capacitor having a large capacity appearance rate, a sintered body using the powder, and the capacitor having the sintered body. SOLUTION: In this powder, a metal containing boron by 1 to 5 mass ppm is used as a main constituent. The powder is used for manufacturing the sintered body. The sintered body is used for manufacturing the capacitor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitor having a large capacitance appearance rate, a powder for the capacitor, and a sintered body using the powder.

[0002]

2. Description of the Related Art Metal silicates such as tantalum and niobium are chemically stable metals and are used for various purposes. For example, tantalum is widely used as a capacitor material for electronic devices such as mobile phones and personal computers. Although niobium has just begun to be studied as a capacitor material, the high dielectric constant performance of the material is highly evaluated. The form of the earth metal used as the capacitor material is usually a powder, and the powder is molded and then sintered to be integrated into an electrode called a sintered body.

The inside of the sintered body has a complicated three-dimensional shape in which the powder is electrically and mechanically connected. After a dielectric film layer is formed inside and outside of these sintered bodies, the other electrode material is impregnated to form a capacitor. As long as the dielectric film layer is uniformly adhered to the surface inside and outside of the sintered body, the capacity of the produced capacitor largely depends on the contact state between the other electrode material and the dielectric film layer. .

On the other hand, it is known that the sinterability of a sintered body can be improved by mixing boron with a powder for a capacitor to increase the specific surface area of the sintered body. For example, JP
Japanese Patent No. 2-109409 (US Pat. No. 4,154,609) discloses that a CV value (capacity C in an electrolytic solution and a dielectric film) is formed by adding 0.01 to 10% by mass of boron nitride. Is multiplied by the formation voltage V. CV is a physical property value proportional to the specific surface area).

[0005]

When a phosphoric acid aqueous solution is used as the other electrode material and the contact state with the dielectric film layer is perfect and the capacitance appearance rate at that time is 100%, a highly viscous electrode material is used. In particular, when a solid electrode material is used, it is difficult to make the capacitance appearance rate 100%. In particular, the difficulty increases as the average particle size of the capacitor powder decreases, and in extreme cases, the capacitance appearance rate may be less than 50%.

[0006]

The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, surprisingly, a powder for a capacitor mainly composed of an earth metal having a very small amount of boron has been found. It has been found that the use of a can achieve a capacity appearance rate that has been impossible in the past, and the present invention has been completed.

That is, according to the present invention, [1] a powder for a capacitor mainly containing earth metal, which is characterized by containing 1 mass ppb to 5 mass ppm of boron; The powder for a capacitor according to the above 1, which is niobium;
[3] The powder for a capacitor according to the above items 1 and 2, wherein the average particle diameter of the powder is 0.2 μm or more and less than 5 μm, [4]
The powder for a capacitor according to any one of Items 1 to 3, wherein the BET specific surface area is 0.5 m ² / g or more and 15 m ² / g or less.

[5] The powder for a capacitor according to any one of [1] to [4], wherein a part of the powder mainly composed of an earth metal is nitrided. [6] The powder for a capacitor according to any one of the preceding items 1 to 5 is granulated,
Granules for capacitors having an average particle size of 10 to 500 μm,
[7] A sintered body obtained by sintering the powder for a capacitor according to any one of the above items 1 to 5, [8] A sintered body obtained by sintering the granulated product for a capacitor according to the above item 6, [9] ] The sintered body according to the above item 7 or 8, wherein the BET specific surface area is 0.2 m ² / g or more and 5 m ² / g or less;

[10] A capacitor comprising the sintered body according to any one of the above items 7 to 9 as one electrode, a dielectric formed on the surface thereof and the other electrode, [1]
1] The capacitor according to the above item 10, wherein the dielectric contains niobium oxide or tantalum oxide as a main component.
2] The capacitor as described in 11 above, wherein the niobium oxide or tantalum oxide is formed by electrolytic oxidation. [13] The other electrode is made of an organic semiconductor, and the organic semiconductor is benzopyrroline 4 Semiconductor composed of a monomer and chloranil, organic semiconductor composed mainly of tetrathiotetracene, organic semiconductor composed mainly of tetracyanoquinodimethane, the following general formulas (1) and (2)

[0010]

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(In the formulas (1) and (2), R ^{1 to} R ⁴ are
Each independently represents a hydrogen atom, a linear or branched saturated or unsaturated alkyl group or alkoxy group having 1 to 6 carbon atoms, X represents an oxygen, sulfur or nitrogen atom,
R ⁵ is present only when X is a nitrogen atom and is hydrogen or carbon 1
Or it represents an alkyl group, R ¹ and R ² and R ³ and R ⁴ may be bonded to form a ring with each other. The capacitor according to any one of Items 10 to 12, wherein the capacitor is at least one selected from the group consisting of an organic semiconductor containing a conductive polymer as a main component obtained by doping a polymer containing two or more repeating units represented by the following formula: 14] The preceding item, wherein the organic semiconductor is a conductive polymer containing at least one selected from polypyrrole, polythiophene and substituted derivatives thereof.
The capacitor described in

[15] The other electrode is made of an organic semiconductor, and the organic semiconductor has the following general formula (3)

[0013]

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(Wherein R ⁶ and R ⁷ are each independently a hydrogen atom, a linear or branched saturated or unsaturated alkyl group having 1 to 6 carbon atoms, Represents a substituent bonded at a position to form a cyclic structure of at least one or more 5- to 7-membered saturated hydrocarbon containing two oxygen elements, and the cyclic structure may be substituted; A conductive polymer obtained by doping a polymer containing two or more repeating units represented by the formula (1) with a vinylene bond and a phenylene structure which may be substituted. 2. The capacitor according to item 1, wherein the polymer containing the repeating unit represented by the general formula (3) is poly (3,4-
Item 17. The capacitor according to item 15, which is ethylenedioxythiophene).

[17] Surface treatment of the capacitor powder according to any one of the above items 1 to 4 by at least one method selected from the group consisting of liquid nitriding, ion nitriding, and gas nitriding. [18] A method for nitriding a capacitor powder according to any one of [1] to [4], wherein the powder for a capacitor is gas-carbonized, solid-phase carbonized, and liquid-carbonized. [19] Any one of the above items [1] to [4], wherein the surface is treated by at least one selected carbonization method.
The method for boring a powder for a capacitor, wherein the powder for a capacitor according to the item is subjected to a surface treatment by at least one kind of a boring method of a gas boring method and a solid-phase boring method.

[20] The surface of the powder for a capacitor according to any one of the above items 1 to 4 is subjected to a surface treatment by at least one of sulfurization methods of gas sulfurization, ion sulfurization and solid phase sulfurization. The method of sulfurizing powder for capacitors
[21] The method for nitriding a capacitor powder according to the above item 17, wherein the capacitor powder is a niobium powder, and [22] the method, wherein the capacitor powder is a niobium powder. 18. The method for carbonizing a powder for a capacitor according to item 18, [23] the method for boriding a powder for a capacitor according to item 19, wherein the powder for a capacitor is niobium powder.

[24] The method for sulfurizing a capacitor powder according to the above item 20, wherein the powder for the capacitor is niobium powder. [25] The above item, wherein the other electrode is made of a material having a layered structure. The capacitor according to 10, [26].
10. The capacitor according to the item 10, wherein the other electrode is a material containing an organic sulfonate anion as a dopant.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment for obtaining a powder for a capacitor according to the present invention will be described. Representative examples of the earth metal used in the present invention include tantalum, niobium, a tantalum-niobium alloy, and an alloy containing these as a main component. Generally available powders can be used as the powder mainly composed of the earth metal oxide. For example, reduction of metal halide earth with magnesium, sodium or hydrogen, sodium reduction of potassium metal fluoride, sodium molten metal salt of potassium metal fluoride (NaCl + KC
1) It can be obtained by electrolysis, reduction of a pentoxide of an earth metal with an alkali metal, an alkaline earth metal or hydrogen, pulverization and dehydrogenation after introducing hydrogen into an ingot of an earth metal.

As a starting material of boron contained in the earth metal, boron oxide, boron nitride, boron carbide, boron sulfide, boron silicide and the following general formula (4): BR ⁸ R ⁹ R ¹⁰ ... (4) (wherein, B is boron, and R ⁸ , R ⁹ , and R ¹⁰ are each independently a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms,
Represents a substituent selected from an alkoxy group having 1 to 6 carbon atoms, an aryl group and a halogen. At least one compound represented by the formula (1) can be used.

The compound represented by the general formula (4) is
It may be a dimer having a boron-boron bond. Examples of the compound represented by the general formula (4) include boron hydride and trialkoxyboron. The content of boron (parts by mass ppb and mass ppm in pp
Abbreviated as b and ppm. ) Is 1ppb to 5pp
m, preferably in the range of 5 ppb to 1 ppm. If it is outside this range, the effect of the present invention cannot be expected.

Next, the operation of the capacitor powder of the present invention will be described. In the capacitor powder of the present invention, the specific surface area of the sintered body is increased by adding a boron in a much smaller concentration than the boron concentration described in JP-A-52-109409. Instead, the capacity can be greatly increased after impregnation with the other electrode material.

When boron is added at a high concentration as conventionally known, the CV value increases as described later, but the capacity cannot be increased after impregnation with the other electrode material. That is, in the present invention, only the capacitance appearance rate is increased. This is thought to be due to the fact that the addition of a small amount of boron has improved the contact state between the other electrode material and the pores inside the sintered body. Can be It is considered that the addition of a large amount of boron rather impedes the impregnation of the other electrode material. When the specific surface area increases, the strength of the sintered body decreases, but such a thing cannot occur in the present invention.

Next, as a method for incorporating a boron compound into the above-mentioned metal earth metal, a predetermined amount of the metal boron compound is mixed with the metal earth metal powder, or boron is used as a raw material or an intermediate for preparing the metal earth metal powder. When the compound is mixed in a predetermined amount, or when the earth metal is an ingot, a method in which a predetermined amount of a boron compound is mixed in the ingot production stage to form a so-called boron-earth metal alloy ingot may be used.

The average particle size of the powder containing boron earth as the main component is not less than 0.1 μm and less than 5 μm, preferably not less than 0.2 μm and less than 5 μm. Average particle size is 5
When the thickness is not less than μm, the CV value of the manufactured sintered body itself is small, and it is difficult to manufacture a capacitor having a large capacity, which is not preferable. When the thickness is less than 0.1 μm, it is difficult to impregnate the other electrode material even with the present invention, and the capacity is reduced, which is not preferable. In the present invention, the specific surface area of the powder in the average particle size range is 0.5 m
^It is preferably not less than ² / g and not more than 15 m ² / g. The powder for a capacitor of the present invention may be used by granulating the powder to a predetermined size.

As the granulation method, a conventionally known method can be adopted. For example, a method in which a powder is left under a high-temperature vacuum at 500 ° C. to 2000 ° C., and then a wet or dry crushing method, a method in which a powder is mixed with a suitable binder such as an acrylic resin or polyvinyl alcohol, and a crushing method, After mixing with an appropriate compound such as resin or camphor, the mixture is allowed to stand under a high temperature vacuum, and then wet or dry pulverized. The particle size of the granulated powder can be arbitrarily changed depending on the degree of granulation and crushing, but usually, an average particle size of 10 μm to 500 μm is used. Classification after granulation and crushing may be used. Also, after granulation, a suitable amount of powder before granulation may be mixed and used.

The powder for a capacitor (including a granulated powder) of the present invention includes a partially nitrided powder, a partially carbonized powder,
The powder may be a partially borated powder or a partially sulfided powder, and particularly preferably a partially nitrided powder.
The nitriding amount is several tens mass ppm to tens of thousands mass ppm. To prepare a sintered body from the powder, form a dielectric on the surface of the sintered body as described below, and measure the LC value in a phosphoric acid aqueous solution, to obtain a small LC value, It is preferable that the amount of nitriding be 300 ppm or more and 7000 ppm or less. Here, the amount of nitriding is not the amount adsorbed on the powder, but the amount reacted and nitrided.

The nitriding of the powder can be carried out by any one of liquid nitriding, ionic nitriding, gas nitriding and the like, or a combination thereof. The gas nitriding treatment in a nitrogen gas atmosphere is preferable because the apparatus is simple and the operation is easy. For example, a gas nitriding method in a nitrogen gas atmosphere is achieved by leaving the powder in a nitrogen atmosphere. The nitriding atmosphere temperature is 2000 ° C. or less, and the leaving time is within several hours, so that a powder having a desired nitriding amount can be obtained.
Processing at a high temperature can shorten the processing time. The amount of nitriding of the powder can be controlled under conditions in which the nitriding temperature and the nitriding time of the nitride to be nitrided are confirmed by preliminary experiments and the like.

In the case of nitriding the granulated powder, a granulated powder may be prepared from the non-granulated powder that has been nitrided, and further subjected to a nitriding treatment. The carbonization of the powder may be any of gas carbonization, solid phase carbonization, and liquid carbonization. For example, the powder may be left together with a carbon material or a carbon source such as an organic substance having carbon such as methane at 2000 ° C. or lower for several minutes to several tens of hours under reduced pressure.

The boriding of the powder may be either gas boriding or solid-phase boriding. For example, the powder is mixed with a boron source such as boron pellets or boron halide such as trifluoroboron under reduced pressure at 2000 ° C. or lower for several minutes to several tens of minutes.
Just leave it for a while.

The sulfurization of the 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 powder in a sulfur atmosphere. The temperature of the sulfurizing atmosphere is 2000 ° C. or less, and the leaving time is within several tens of hours. Further, the processing time can be reduced by performing the processing at a higher temperature.

The nitriding method, the carbonizing method, the boride method, and the sulfurizing method can be performed not only on niobium powder but also on an untreated niobium sintered body.
The sintered body of the present invention is manufactured by sintering the powder described above.
One example of a method for manufacturing a sintered body will be described below. The method for manufacturing the sintered body is not limited to this example. For example, after the powder is pressed into a predetermined shape, (1 to 1
0 ^-7) × at 133Pa (Pascal), a few minutes to a few hours, 5
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. The specific surface area of the sintered body of the present invention is 0.2 m ² / g.
Above is preferably 5 m ² / g or less.

Further, a lead wire having a suitable shape and length and made of a valve metal such as niobium or tantalum is prepared.
The lead wire may be integrally molded so that a part of the lead wire is inserted into the inside of the molded body during the pressure molding of the powder, and the lead wire may be designed so as to be a lead of the sintered body. it can.

A capacitor can be manufactured from the above-described sintered body as one electrode and a dielectric interposed between the other electrodes. As the dielectric of the capacitor, a dielectric mainly composed of niobium oxide and tantalum oxide can be cited. For example, a dielectric containing niobium oxide as a main component can be obtained by forming a niobium sintered body as one electrode in an electrolytic solution. The formation of a niobium electrode in an electrolytic solution is usually performed using a protonic acid aqueous solution, for example, a 0.1% phosphoric acid aqueous solution or a sulfuric acid aqueous solution. A case where a niobium electrode is formed in an electrolytic solution to obtain a dielectric mainly composed of niobium oxide.
The capacitor of the present invention becomes an electrolytic capacitor, and the niobium side becomes an anode.

On the other hand, in the present invention, the other electrode of the capacitor includes at least one compound selected from an organic semiconductor and an inorganic semiconductor. Specific examples of the organic semiconductor include an organic semiconductor composed of 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 the general formula (2)

[0035]

Embedded image

(In the above formulas (1) and (2), R ^{1 to} R ⁴
Are each independently a hydrogen atom, a linear or branched saturated or unsaturated alkyl group having 1 to 6 carbon atoms,
R represents an alkoxy group, X represents an oxygen, sulfur or nitrogen atom, R ⁵ represents hydrogen or an alkyl group having 1 to 6 carbon atoms and present only when X is a nitrogen atom, and R ¹ , R ² and R ³ And R ⁴
May be bonded to each other to form a ring. An organic semiconductor mainly composed of a conductive polymer obtained by doping a dopant into a polymer containing two or more repeating units represented by the formula (1) can be preferably used.

Examples of the polymer containing a repeating unit represented by the formula (1) or (2) include polyaniline, polyoxyphenylene, polyphenylene sulfide, polythiophene, polyfuran, polypyrrole, polymethylpyrrole, and polymethylpyrrole. And the like. Further, a more preferred embodiment of the above general formula (1) is the following general formula (3)

[0038]

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(Wherein R ⁶ and R ⁷ each independently represent a hydrogen atom, a linear or branched saturated or unsaturated alkyl group having 1 to 6 carbon atoms, Represents a substituent bonded at a position to form a cyclic structure of at least one or more 5- to 7-membered saturated hydrocarbon containing two oxygen elements, and the cyclic structure may be substituted; Organic polymers having a conductive polymer obtained by doping a dopant into a polymer containing two or more repeating units represented by the following formulas: those having a vinylene bond and those having a phenylene structure which may be substituted are included. No. 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 ferric oxide. Such semiconductors may be used alone or in combination of two or more.

As the above organic semiconductor and inorganic semiconductor,
Using a range of electric conductivity of ^{10-2 2} S · cm ^-1 to 10 ³ S · cm ^-1, it is possible impedance value of the capacitor fabricated becomes smaller, further more it increases the capacity of a high frequency. Further, 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 by, for example, 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, it is left in the air or heated to be solidified. 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 an aluminum 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 sintered body or later welded. The capacitor of the present invention having the above configuration includes, for example, a resin mold, a resin case, a metal outer case,
Capacitor products for various applications can be obtained by coating with resin dipping, or using a laminate film.

[0043]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. The amount of boron contained in the powder of the present invention was measured by a separation method using an anion exchange column (anion exchange separation method).
The nitriding amount of the powder was determined using a nitrogen / oxygen analyzer manufactured by LEKO. The CV value of the sintered body was determined by applying 20 V in a 0.1% phosphoric acid aqueous solution, and performing 80 differentiation at 200C.
Capacity measured in 30% sulfuric acid and 70% of formation voltage 1
It was determined from the product with 4V. The capacity appearance rate was expressed as a ratio to the capacity after formation of the capacitor, with the capacity in 30% sulfuric acid at the time of 1000 differentiation under the above-mentioned conditions as 100%. The number of samples for obtaining the CV value and the capacitance appearance rate was 30 in each case.

(Examples 1 to 6) and (Comparative Examples 1 to 3) Triethylboron prepared separately was added to niobium powder having an average particle size of 0.9 μm in predetermined amounts, and the boron content was as shown in Table 1. It was prepared so that Then, the powder of each example was
After being heated in vacuum at 000 ° C., it was taken out, crushed and classified to obtain granulated powder having an average particle size of 90 μm. In each case, the granulated powder was molded into a size of 1.8 mm × 3.5 mm × 4.5 mm (a niobium wire having a diameter of 0.3 mm was molded into a lead), and then 5 × 133 at 1250 ° C. × 10 ^-5 Pa
It was sintered under (Pascal) vacuum to obtain a sintered body. Table 1 shows the CV values of the sintered bodies.

Next, after forming the sintered body in the same manner as in the case of obtaining the CV value except that the formation time of the sintered body was set to 1000 minutes, the other electrode material was made of polypyrrole (an oxidizing agent was ammonium persulfate, and a dopant was anthraquinone sulfone). The reaction between pyrrole and the oxidizing agent was repeated in the presence of a dopant in the presence of a dopant) to fill the pores inside the sintered body. Furthermore, after laminating a carbon paste and a silver paste in order, sealing was performed with an epoxy resin to produce a capacitor. Table 1 shows the capacity appearance rate of each example.

(Examples 7 to 12) and (Comparative Examples 4 to 6) In Examples 1 to 6 and Comparative Examples 1 to 3, the other electrode material was changed from polypyrrole to a mixture of lead dioxide and lead sulfate (lead dioxide was 98%).
The reaction between the aqueous solution of lead acetate and the aqueous solution of ammonium persulfate was repeated in the mass% of the sintered body pores. ), And a capacitor was produced in the same manner as in Examples 1 to 6 and Comparative Examples 1 to 3.

(Examples 13 to 18), (Comparative Examples 7 to 9) In Examples 1 to 6 and Comparative Examples 1 to 3, the average particle size of niobium powder was changed from 0.9 μm to 2 μm, and triethylboron was changed to boron oxide. And the capacitors were produced in the same manner as in Examples 1 to 6 and Comparative Examples 1 to 3 except that the average particle size of the granulated powder was changed to 110 μm.

(Examples 19 to 24), (Comparative Examples 10 to 1)
2) In Examples 1 to 6 and Comparative Examples 1 to 3, the niobium powder having an average particle diameter of 0.9 μm was converted into a tantalum powder having an average particle diameter of 0.7 μm, and the average particle diameter of the granulated powder was changed to 150 μm. Temperature 1
Examples 1 to 6, except that the temperature was changed from 250 ° C to 1480 ° C,
A capacitor was produced in the same manner as in Comparative Examples 1 to 3.

[0049]

[Table 1]

(Examples 25 to 30), (Comparative Examples 13 to 1)
5) In Examples 1 to 6 and Comparative Examples 1 to 3, the other electrode material was an organic semiconductor (dielectric material) in which poly (3,4-ethylenedioxythiophene) was doped with anthraquinone-2-sulfonic acid anion from polypyrrole. Examples 1 to 10 were performed except that the polymer was formed on the formed sintered body by the following method.
6. A capacitor was produced in the same manner as in Comparative Examples 1 to 3, and the evaluation results are shown in Table 2.

Hereinafter, a method for producing a sintered body having the polymer will be described. Fifty sintered bodies were prepared in the same manner as the sintered bodies obtained in Examples 1 to 6 and Comparative Examples 1 to 3, and these sintered bodies were applied at a voltage of 20 V using a 0.1% phosphoric acid aqueous solution. ,
Electrolysis was performed for 200 minutes to form a dielectric oxide film on the surface. Next, the niobium sintered body was immersed in an aqueous solution (solution 1B) containing 25% by mass of ammonium persulfate and 3% by mass of sodium anthraquinone-2-sulfonate, pulled up, dried at 80 ° C. for 30 minutes, and then dried. The sintered body on which the dielectric was formed was treated with an isopropanol solution containing 18% by mass of 3,4-ethylenedioxythiophene (solution 2).
After being immersed in the solution, it was pulled up and left in an atmosphere of 60 ° C. for 10 minutes to perform oxidative polymerization.

This was immersed again in the solution 1B and further treated in the same manner as described above. The operation from immersion in the solution 1B to oxidative polymerization was repeated 10 times, followed by washing with warm water at 50 ° C. for 10 minutes and drying at 100 ° C. for 30 minutes to obtain a conductive poly (3, The other electrode (counter electrode) made of 4-ethylenedioxythiophene) was formed. The capacitors were manufactured in the same manner as in Examples 1 to 6 and Comparative Examples 1 to 3.

[0053]

[Table 2] Examples 1 to 6 and Comparative Examples 1 to 3, Examples 7 to 12 and Comparative Examples 4 to 6, Examples 13 to 18 and Comparative Examples 7 to 9, and Example 19
-24 and Comparative Examples 10-12, and Examples 25-30 and Comparative Examples 13-15 respectively,
It can be seen that when a capacitor is produced from a powder mainly composed of an earth metal metal containing pb to 5 ppm, the capacitance appearance rate of the capacitor increases.

[0054]

According to the powder for capacitors of the present invention, a sintered body using the powder, and a capacitor having the sintered body,
A capacitor having a large capacitance appearance rate can be manufactured.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C04B 35/58 105 C04B 35/56 F H01G 9/028 H01G 9/02 331A 331E F-term (Reference) 4G001 BA12 BA24 BA37 BA43 BA61 BA68 BB12 BB24 BB37 BB43 BB68 BC02 BC71 BD23 4G030 AA20 AA21 AA35 AA45 AA49 AA54 BA09 GA06

Claims (26)

[Claims] 1. A powder for a capacitor mainly composed of a metal earth metal, comprising 1 to ppb to 5 ppm by mass of boron. 2. The capacitor powder according to claim 1, wherein the earth metal is niobium. 3. The powder having an average particle size of 0.2 μm or more and 5 μm or more.
3. The powder for a capacitor according to claim 1, wherein the particle diameter is less than m. 4. When the BET specific surface area is 0.5 m ² / g or more, 15
The powder for a capacitor according to any one of claims 1 to 3, wherein the powder is not more than m ² / g. 5. The capacitor powder according to claim 1, wherein a part of the powder mainly composed of an earth metal is nitrided. 6. An average particle diameter obtained by granulating the powder for a capacitor according to claim 1 having an average particle diameter of 10 to 500 μm.
Granules for capacitors. 7. A sintered body obtained by sintering the powder for a capacitor according to any one of claims 1 to 5. 8. A sintered body obtained by sintering the granulated product for a capacitor according to claim 6. 9. A BET specific surface area of 0.2 m ² / g or more and 5 m
^The sintered body according to claim 7, wherein the sintered body is not more than ² / g. 10. A capacitor comprising the sintered body according to claim 7 as one electrode, a dielectric formed on the surface thereof, and the other electrode. 11. The capacitor according to claim 10, wherein the dielectric contains niobium oxide or tantalum oxide as a main component. 12. The capacitor according to claim 11, wherein the niobium oxide or tantalum oxide is formed by electrolytic oxidation. 13. The other electrode comprises an organic semiconductor, wherein the organic semiconductor comprises benzopyrroline tetramer and chloranil, an organic semiconductor comprising tetrathiotetracene as a main component, and tetracyanoquinodimethane as a main component. An organic semiconductor to be represented by the following general formula (1) and general formula (2): (In the formulas (1) and (2), R ^{1 to} R ⁴ each independently represent a hydrogen atom, a linear or branched saturated or unsaturated alkyl group or alkoxy group having 1 to 6 carbon atoms. X represents an oxygen, sulfur or nitrogen atom, R ⁵ represents hydrogen or an alkyl group having 1 to 6 carbon atoms and exists only when X is a nitrogen atom, and R ¹ and R ² and R ³ and R ⁴ May be bonded to each other to form a ring.) At least one selected from the group consisting of organic semiconductors containing a conductive polymer obtained by doping a dopant into a polymer containing two or more repeating units represented by the following formula: The capacitor according to claim 10, which is a kind. 14. The capacitor according to claim 13, wherein the organic semiconductor is a conductive polymer containing at least one selected from polypyrrole, polythiophene and substituted derivatives thereof. 15. The other electrode comprises an organic semiconductor, wherein the organic semiconductor is represented by the following general formula (3): (Wherein, R ⁶ and R ⁷ each independently represent a hydrogen atom, a linear or branched saturated or unsaturated alkyl group having 1 to 6 carbon atoms, or the alkyl groups are bonded to each other at an arbitrary position. Represents a substituent which forms a cyclic structure of at least one or more 5- to 7-membered saturated hydrocarbon containing two oxygen elements, wherein the cyclic structure has a vinylene bond which may be substituted. A conductive polymer obtained by doping a polymer containing two or more repeating units represented by the formula (1) with a phenylene structure which may be substituted. A capacitor according to claim 1. 16. The capacitor according to claim 15, wherein the polymer containing the repeating unit represented by the general formula (3) is poly (3,4-ethylenedioxythiophene). 17. The surface treatment of the powder for a capacitor according to claim 1 by at least one method selected from the group consisting of liquid nitriding, ion nitriding, and gas nitriding. A method for nitriding a powder for a capacitor, comprising: 18. The surface of the powder for a capacitor according to any one of claims 1 to 4 by at least one carbonization method selected from the group consisting of gas carbonization, solid phase carbonization and liquid carbonization. A carbonization method for powder for capacitors, characterized by being subjected to a treatment. 19. A surface treatment of the powder for a capacitor according to any one of claims 1 to 4 by at least one of boriding methods of gas boriding and solid-phase boriding. Boriding method of powder for capacitor. 20. A surface treatment of the powder for a capacitor according to any one of claims 1 to 4 by at least one of sulfurization methods of gas sulfurization, ion sulfurization and solid phase sulfurization. Method for sulphating powder for capacitors. 21. The method of claim 17, wherein the capacitor powder is niobium powder. 22. The method according to claim 18, wherein the capacitor powder is niobium powder. 23. The method according to claim 19, wherein the capacitor powder is niobium powder. 24. The method according to claim 20, wherein the powder for a capacitor is niobium powder. 25. The capacitor according to claim 10, wherein the other electrode is made of a material having a layered structure. 26. The capacitor according to claim 10, wherein the other electrode is made of a material containing an organic sulfonate anion as a dopant.