RU2299786C2 - Niobium powder, sintered niobium material and capacitor made with use of such sintered material - Google Patents

Abstract

FIELD: powder metallurgy, namely production of niobium powder, possibly used manufacture of capacitors and electronic devices.

SUBSTANCE: niobium powder for making capacitors contains at least one element selected from group including nitrogen, carbon, boron, sulfur and it has bulk density 0.5 - 2.5 g/ml. Powder is produced by activation treatment of initial niobium powder or niobium material. Sintered material for making capacitors is produced from prepared niobium powder by sintering or extrusion. Sintered material features large number of maximums of pore diameter distribution.

EFFECT: large capacity of capacitor for mass unit, low leakage current, high moisture resistance.

63 cl, 2 dwg, 7 tbl, 19 ex

Description

Links to related applications

This application is based on section 35 of the U.S. Code of Law, part 111 (a), claims priority on the filing date of the application having registration number 60/291925 and filed with the US Patent Office May 21, 2001, and on the filing date of the application having the registration number 60/331200 filed with the U.S. Patent Office on November 9, 2001, pursuant to section 35 of the U.S. Code, Part 111 (b), in accordance with section 35 of the U.S. Code, Part 119 (e) (1).

Technical field

The present invention relates to a niobium powder and sintered material obtained from it, which can be purposefully used for the manufacture of a capacitor having a large capacity per unit mass, good leakage current characteristics and excellent moisture resistance, the invention also relates to a capacitor made using niobium powder and sintered material, as well as to methods for producing niobium powder, sintered material and capacitor.

State of the art

Capacitors intended for use in electronic devices such as a portable telephone and personal computer must have a small size and significant capacity. Among such capacitors, a tantalum capacitor is preferable, due to its considerable capacitance with a small size and good performance.

In addition, modern electronic devices must operate at low voltage and high frequency with low noise, it is also required that the capacitor with a solid electrolyte has a low equivalent series resistance (EPS).

In such a tantalum based capacitor, as a rule, sintered material obtained from tantalum powder is used for the anode part. This powder is first formed and then sintered, and an agglomerate is formed from the powder and an electrode called sintered material is formed. The inner part of this sintered material assumes a complex three-dimensional shape due to the fact that the powder particles are mechanically and electrically connected to each other. A dielectric film layer is formed on the surface of this sintered material, including the surface of the internal pores, and this material is impregnated as a counter electrode, and thus a capacitor is made. Since the dielectric film layer adheres uniformly to both the outer and inner surfaces of the sintered material, the capacitance of the fabricated capacitor substantially depends on the microscopic level on the state of contact of the material of the counter electrode with the dielectric film layer.

In order to increase the capacity of a tantalum capacitor, it is necessary to increase the mass of sintered material or to use sintered material with an increased surface area as a result of grinding tantalum powder.

A method of increasing the mass of sintered material necessarily leads to an increase in the size of the capacitor and cannot satisfy the requirement of downsizing. On the other hand, when implementing the method of grinding tantalum powder in order to increase the specific surface area, the pore diameter of the sintered tantalum-based material is reduced, or the number of closed pores is increased at the sintering stage, which makes it difficult to impregnate the cathode agent in subsequent stages.

For example, assuming that in the case of using an aqueous solution of phosphoric acid as the counter electrode material, the state of complete contact of the solution with the dielectric film layer is achieved, and the capacity realization coefficient (also called the cathode impregnation coefficient) is 100%, in the case of using the counter electrode material, having a high viscosity, in particular solid electrode material, a capacity factor of 100% is unlikely to be achieved. In particular, if the average particle size of the tantalum powder is small or the sintered material made from tantalum powder has a significant size, the difficulties increase, and in an extreme situation, the capacity factor does not even reach 50%. With such a low coefficient of capacity realization, the manufactured capacitor cannot have a sufficiently high moisture resistance.

In the event that the tantalum powder used to make the sintered tantalum material has a small pore diameter, this essentially leads to a small pore diameter in the sintered tantalum material and a low capacity factor. Therefore, a problem arises that the EPS cannot be reduced.

As one of the means to solve these problems, a capacitor can be considered, in which sintered material is used as an electrode, and sintered material is produced using an electrode material providing a dielectric material having a higher dielectric constant than the dielectric constant of tantalum, which allows achieve a high coefficient of capacity realization.

As such an electrode material that can be manufactured industrially, niobium is known to have a higher dielectric constant than tantalum, and there are large reserves thereof.

JP-A-55-157226 (the designation “JP-A” means an unexamined published Japanese patent application) discloses a method for producing a sintered element for capacitors, according to which agglomerated metal powder of valve action, with a particle size of 2.0 microns or less , molded and then sintered, the molded and sintered material is crushed into small pieces, a portion of lead is added to them and sintered again. However, the details of the production method and the properties of the niobium capacitor are not described in this published application.

US Pat. No. 4,084,965 discloses a capacitor using sintered material obtained from a niobium powder having an average particle size of 5.1 μm obtained by hydrogenation and pulverization of a niobium ingot. However, the described capacitor has a significant leakage current (hereinafter referred to for brevity as "TU") and is of little practical interest.

JP-A-10-242004 (WO 98/38660) discloses a method for partially nitriding a niobium powder and thereby improving the performance of TU.

The bulk density of niobium powder for the manufacture of capacitors is an important factor for the operation of molding niobium powder. The bulk density of the commonly used niobium powder is 2.5 g / ml or more, namely, in particular about 4 g / ml, and this is not suitable for molding.

This means that when such a niobium powder is molded and sintered to obtain sintered material, the niobium powder does not flow well from the hopper loading device into the metal mold, therefore, difficulties arise when weighing a constant amount of powder and moving it into the metal mold. As a result of this, problems such as insufficient shape stability of the pressed product, insufficient strength of the pressed product and sintered material, and the obtained capacitor often have unsatisfactory TU characteristics. In that case, if special equipment is used to work with a powder having poor fluidity, the molding cost increases significantly, which is impractical.

Thus, the use of the well-known niobium powder for the manufacture of capacitors is associated with the problem that the powder is not quite suitable for continuous molding, and the production capacity of the capacitors is small.

SUMMARY OF THE INVENTION

The present invention was based on the task of creating a capacitor having a large capacity per unit mass and characterized by a low leakage current and high moisture resistance; the invention also relates to sintered material suitable for use as an electrode material of such a capacitor and capable of providing a high coefficient of capacity realization; In addition, the invention relates to a niobium powder, which is preferred as a starting material for such a sintered material and has good flow during molding operations, facilitating continuous molding, and facilitating stable production of capacitors; The invention also relates to a method for manufacturing a capacitor, sintered material and niobium powder.

As a result of extensive research aimed at solving the above problems, the authors of the present invention have found that in the case when a sintered niobium material having a special pore size distribution, preferably having many pore diameter maxima in the pore size distribution, is used to make the capacitor electrode, a high capacitance factor has been achieved, and a capacitor having a low leakage current and high moisture resistance can be obtained. The inventors of the present invention have found that it is preferable to use niobium powder having a bulk density of from 0.5 to 2.5 g / ml, more preferably having an average particle size of from 10 to 1000 μm, having good fluidity as the material for the above sintered material, which makes continuous molding possible. Such a powder is preferred for the manufacture of the sintered material described above, and when such a powder is used, it is possible to purposefully produce a capacitor having a low leakage current and high moisture resistance. The authors of the present invention have found that it is more preferable, both to achieve a high capacity realization coefficient and a low ESR value, to manufacture a capacitor in which the electrodes are made using sintered niobium material obtained using a niobium powder having a wide pore size distribution and having many maximums in the distribution of pore sizes, and all pore diameters are 0.5 μm or more. The present invention is based on these findings.

More specifically, the present invention relates to the following niobium powder, sintered niobium material, a capacitor made using it, and methods for manufacturing a capacitor, sintered material and niobium powder.

(1) Niobium powder for the manufacture of a capacitor having a bulk density of from 0.5 to 2.5 g / ml.

(2) Niobium powder, as described above in paragraph 1, in which the average particle size is from 10 to 1000 microns.

(3) Niobium powder, as described above in paragraphs 1 and 2, in which the angle of repose is from 10 ° to 60 °.

(4) Niobium powder, as described above in any of paragraphs 1 to 3, in which the specific surface, determined by adsorption isotherms by the Braunauer-Emet-Teller method (BET surface), is from 0.5 to 40 m ² / g .

(5) Niobium powder, as described above in any one of items 1 to 4, wherein the pore size distribution has a maximum pore diameter in the range of 0.01 μm to 500 μm.

(6) Niobium powder, as described in paragraph 5 above, according to which there are many pore diameter maxima in the pore size distribution.

(7) Niobium powder, as described above in paragraphs 5 or 6, in which one of the maxima of the distribution of pore sizes is in the range from 0.5 to 100 microns.

(8) Niobium powder, as described above in any one of items 1 to 7, in which at least one element selected from the group consisting of nitrogen, carbon, boron and sulfur is contained in an amount of from 200,000 parts by weight. per million or less.

(9) Sintered material obtained using niobium powder according to any one of the above 1 to 8.

(10) Sintered material, as described above in paragraph 9, which is characterized by a pore size distribution having a maximum pore diameter in the range from 0.01 μm to 500 μm.

(11) Sintered niobium material for manufacturing a capacitor electrode, which is characterized by a pore size distribution in which there are many pore diameter maxima.

(12) Sintered niobium material, as described in paragraph 11 above, which is characterized by a pore size distribution in which there are two maximum pore diameters.

(13) Sintered niobium material, as described above in paragraphs 11 or 12, in which the set of pore diameter maxima contains two maxima with the highest relative intensity, which are in the range from 0.2 to 0.7 μm and in the range from 0.7 up to 3 microns, respectively.

(14) Sintered niobium material, as described above in paragraphs 11 to 13, which has a maximum with the highest relative intensity among the plurality of maxima of the pore diameter, which is in the region of larger diameters than the maximum with the next largest relative intensity.

(15) Sintered niobium material, as described above in paragraphs 9 to 14, which is characterized by a pore volume of 10 mm ³ or more, including empty pore volume.

(16) Sintered niobium material, as described above in paragraphs 9 to 15, which has a specific surface area of 0.2 to 7 m ² / g.

(17) Sintered niobium material, as described above in paragraphs 9 to 16, part of which is nitrided.

(18) Sintered niobium material, as described above in paragraphs 12 to 17, obtained from a molded niobium product, which allows sintered material having a specific charge CV equal to from 40,000 to 200,000 μFV / g, if the material subjected to sintering at a temperature of 1300 ° C.

(19) A capacitor including one electrode made using sintered niobium material, as described above in any of paragraphs 9 to 18, a counter electrode and a dielectric material located between them.

(20) The capacitor, as described above in paragraph 19, in which the dielectric material mainly includes niobium oxide.

(21) The capacitor, as described in paragraph 19 above, wherein the counter electrode is at least one material selected from the group consisting of an electrolyte solution, an organic semiconductor, and an inorganic semiconductor.

(22) The capacitor, as described in paragraph 21 above, according to which the counter electrode is an organic semiconductor, and the organic semiconductor is at least one substance selected from the group consisting of an organic semiconductor including a tetramer of benzopyrroline and chloranil, an organic semiconductor, in mainly comprising tetratiotetracene, an organic semiconductor, mainly comprising tetracyanoquinodimethane and an electrically conductive polymer.

(23) A capacitor, as described in paragraph 22 above, wherein the electrically conductive polymer is at least one polymer selected from the group consisting of polypyrrole, polythiophene, polyaniline and their substituted derivatives.

(24) The capacitor according to paragraph 22 above, according to which the electrically conductive polymer is an electrically conductive polymer obtained by introducing a dopant into a polymer containing a repeating unit represented by the following formulas (1) and (2):

(where the radicals from R ¹ to R ⁴ each independently represent a monovalent group selected from the group consisting of hydrogen, a linear or branched, saturated or unsaturated alkyl, alkoxy or alkyl substituted ester group containing from 1 to 10 carbon atoms, a halogen atom, a nitro group , a cyano group, a primary, secondary or tertiary amino group, a CF ₃ group, phenyl or substituted phenyl; each of the pairs R ¹ and R ² , R ³ and R ⁴ may optionally be combined to form a bivalent chain to produce at least one 3-, A 4-, 5-, 6- or 7-membered saturated or unsaturated cyclic hydrocarbon structure together with carbon atoms substituted by R ¹ and R ² radicals or R ³ and R ⁴ radicals; the combined cyclic chain may contain a bond with a carbonyl ether group , an ester group, an amide group, a sulfide group, sulfinyl, sulfonyl or an imino group in an arbitrary position; X represents an oxygen atom, a sulfur atom or a nitrogen atom; R ^{5 is} present only when X represents a nitrogen atom, and independently represents a hydrogen atom or a linear or branched, saturated or unsaturated alkyl group containing from 1 to 10 carbon atoms).

(25) The capacitor according to paragraph 24 above, in which the electrically conductive polymer is an electrically conductive polymer containing a repeating unit represented by the following formula (3):

(in which R ⁶ and R ⁷ each independently represents a hydrogen atom, a linear or branched, saturated or unsaturated alkyl group containing from 1 to 6 carbon atoms, or a substituent capable of forming at least one 5-, 6- or 7-membered a saturated cyclic hydrocarbon structure containing two oxygen moieties derived from alkyl groups that combine with each other in an arbitrary position; the cyclic structure includes a structure containing a vinylene bond which may be substituted and phenyl new structure that may be substituted).

(26) The capacitor according to paragraph 22 above, wherein the electrically conductive polymer is an electrically conductive polymer obtained by introducing a dopant into poly (3,4-ethylenedioxythiophene).

(27) The capacitor according to paragraph 19 above, in which the counter electrode is made of a material at least partially having a layered structure.

(28) The capacitor according to paragraph 19 above, wherein the counter electrode material contains an organic anion sulfonate as a dopant.

(29) A method for producing a niobium powder as described in any of the above 1 to 8, comprising activating the treatment of niobium or a niobium compound.

(30) The method for producing niobium powder according to paragraph 29 above, according to which the activation treatment of niobium or a niobium compound is carried out in at least one step selected from a sintering step and a crushing step.

(31) The method for producing niobium powder according to paragraphs 29 or 30 above, wherein the activation treatment of niobium or a niobium compound is carried out using a mixture of niobium or a niobium compound with an activator.

(32) The method for producing the niobium powder according to any one of items 29 to 31 above, wherein the average particle size of the niobium or niobium compound subjected to the activation treatment is from 0.01 μm to 10 μm.

(33) A method for producing a niobium powder according to any one of items 29 to 32 above, wherein the niobium or niobium compound contains at least one element selected from the group consisting of nitrogen, carbon, boron and sulfur in an amount of 200,000 parts by weight . per million or less.

(34) The method for producing niobium powder according to any one of items 29 to 33 above, wherein the niobium compound is at least one compound selected from the group consisting of niobium hydride, niobium alloy or niobium hydride alloy.

(35) The method for producing the niobium powder according to paragraph 34 above, wherein the component other than niobium contained in the niobium alloy or in the niobium hydride alloy is at least one element selected from the group consisting of elements having atomic numbers from 88 or lower, with the exception of hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, iodine, niobium, helium, neon, argon, krypton, xenon and radon.

(36) The method for producing niobium powder according to paragraph 31 above, according to which a mixture containing niobium or a niobium compound and an activator is obtained by mixing them using a solvent.

(37) The method for producing the niobium powder according to paragraph 36 above, wherein the solvent is at least one solvent selected from the group consisting of water, alcohols, ethers, cellosolves, ketones, aliphatic hydrocarbons, aromatic hydrocarbons and halogenated hydrocarbons .

(38) The method for producing niobium powder according to paragraph 31 above, according to which the activator is used in an amount of from 1 to 40 wt.%, Based on the total amount of niobium or niobium compound.

(39) The method for producing niobium powder according to paragraph 31 or 38 above, according to which the average particle size of the activator is from 0.01 μm to 500 μm.

(40) The method for producing niobium powder according to any one of paragraphs 31, 38 or 39 above, according to which the activator is characterized by the presence of several maxima of the particle size distribution.

(41) The method for producing the niobium powder according to any one of paragraphs 31 or 38 to 40 above, wherein the activator is a substance that is removed as a gas at 2000 ° C. or less.

(42) The method for producing the niobium powder according to paragraph 41 above, wherein the activator is at least one compound selected from the group consisting of naphthalene, anthracene, quinone, camphor, polyacrylic acid, acrylic acid ester polymer, polyacrylamide, polymethacrylic acid, methacrylic acid ester polymer, polymethacrylamide, polyvinyl alcohol, NH ₄ Cl, ZnO, WO ₂ , SnO ₂ and MnO ₃ .

(43) The method for producing the niobium powder according to any one of paragraphs 31 or 38 to 40 above, wherein the activator is at least one compound selected from the group consisting of a water-soluble compound, a compound soluble in organic solvents, a compound, soluble in solutions of acids, a compound soluble in solutions of alkalis, a compound forming a complex providing the solubility of the compound in water, an organic solvent, an acid solution or an alkaline solution, and the compound eniya which becomes soluble in water, organic solvent, acidic solution or alkaline solution at a temperature of 2000 ° C or less.

(44) The method for producing the niobium powder according to paragraph 43 above, wherein the activator is at least one compound selected from the group consisting of metal compounds with carboxylic acid, sulfuric acid, sulphurous acid, halogen, perhalogen acid, hypohalogen acid , nitric acid, nitrous acid, phosphoric acid, acetic acid, oxalic acid or boric acid, metals, metal hydroxides and metal oxides.

(45) The method for producing the niobium powder according to paragraph 43 above, wherein the activator is at least one compound selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, France, beryllium, magnesium, calcium, strontium , barium, radium, scandium, yttrium, cerium, neodymium, titanium, zirconium, hafnium, vanadium, niobium, tantalum, molybdenum, tungsten, manganese, rhenium, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, silver , gold, zinc, cadmium, boron, aluminum, gallium, indium, thallium, silicon, ger anija, tin, lead, arsenic, antimony, bismuth, selenium, tellurium, polonium and compounds thereof.

(46) The method for producing the niobium powder according to any one of 29 to 40 and 43 to 45 above, wherein the activation treatment is a treatment in which the activator is removed by heating and / or under reduced pressure before or during the sintering step. .

(47) The method for producing the niobium powder according to any one of 29 to 40 and 43 to 45 above, wherein the activation treatment is a treatment in which the activator component is removed by contacting the solvent with a sintered or crushed product after the sintering step and during or after the crushing stage.

(48) The method for producing the niobium powder according to paragraph 47 above, wherein the solvent is at least one compound selected from the group consisting of water, an organic solvent, an acid solution or an alkaline solution, and a solution containing a ligand to form a soluble complex .

(49) The method for producing the niobium powder according to paragraph 48 above, wherein the acid solution is a solution of at least one compound selected from the group consisting of nitric acid, sulfuric acid, hydrofluoric acid and hydrochloric acid.

(50) The method for producing the niobium powder according to paragraph 49 above, wherein the alkaline solution contains at least one compound selected from the group consisting of alkali metal hydroxide and ammonia.

(51) The method for producing the niobium powder according to paragraph 48 above, wherein the ligand is at least one compound selected from the group consisting of ammonia, glycine and ethylenediaminetetraacetic acid.

(52) The method for producing the niobium powder according to paragraph 48 above, wherein the organic solvent is methyl isobutyl ketone.

(53) A method for producing a nitrogen-containing niobium powder, comprising treating a niobium powder according to any one of 1 to 7 above using at least one method selected from the group consisting of liquid-phase nitriding, ion nitriding and gas-phase nitriding.

(54) A method for producing a carbon-containing niobium powder, comprising treating the niobium powder according to any one of 1 to 7 above using at least one method selected from the group consisting of solid phase carbonization and liquid phase carbonization.

(55) A method for producing a boron-containing niobium powder, comprising treating the niobium powder according to any one of 1 to 7 above using at least one method selected from the group consisting of gas-phase boronization and solid-phase boronation.

(56) A method for producing a sulfur-containing niobium powder, comprising treating the niobium powder according to any one of 1 to 7 above using at least one method selected from the group consisting of gas phase sulfidation, ionic sulfidation and solid phase sulfidation.

(57) Niobium powder obtained by the method described in any of paragraphs 29 to 56 above.

(58) A method for producing a sintered niobium material, the implementation of which uses niobium powder according to the above items 1 to 8 and 57.

(59) A method of manufacturing a capacitor including one electrode based on sintered niobium material, a dielectric material formed on the surface of the sintered material, and a counter electrode that is located on the dielectric material, where the sintered niobium material is obtained by sintering niobium powder according to the above from 1 to 8 and 57.

(60) A method of manufacturing a capacitor according to paragraph 59 above, according to which a dielectric material is formed by electrolytic oxidation.

(61) A method for manufacturing a capacitor comprising one electrode based on sintered niobium material, a dielectric material formed on the surface of the sintered material, and a counter electrode that is located on the dielectric material using sintered niobium material according to any one of the above from 9 to 18.

(62) An electronic circuit manufactured using a capacitor according to any one of the above from 19 to 28.

(63) An electronic device made using a capacitor according to any one of the above from 19 to 28.

Brief Description of the Drawings

Figure 1 in an enlarged view schematically shows the niobium powder according to the present invention, which is characterized by two or more maximum pore diameters.

Figure 2 shows the pore size distribution curve for niobium powder obtained by mercury porosimetry.

The method of carrying out the invention

The following describes a capacitor with good leakage current characteristics and excellent moisture resistance, sintered niobium material, which provides such properties and leads to a high capacity factor, niobium powder, which is preferred as a starting material for such sintered material and has good flowability and is suitable for the implementation of continuous molding, and methods for manufacturing a capacitor, sintered niobium material and niobium powder.

According to the present invention, niobium powder for capacitors (sometimes simply referred to as “niobium powder”) having a bulk density of from 0.5 to 2.5 g / ml is used as a niobium powder, which is suitable for the manufacture of capacitors with the properties described above and allows improve capacitor manufacturing performance.

The term "niobium powder for capacitors" when used in the present description means niobium powder, which mainly consists of niobium and can be used for the manufacture of capacitors. The specified niobium powder may contain, for example, a component capable of forming alloys with niobium, namely a component other than niobium, such as nitrogen and / or oxygen.

A capacitor can be obtained by molding and sintering a niobium powder for capacitors using the method described below for producing sintered niobium material for capacitors (sometimes simply referred to as sintered niobium material), followed by the formation of a dielectric layer and a counter electrode thereon.

The niobium powder for the capacitors is added to the solution obtained by dissolving the binder, which is described below, in an organic solvent, such as toluene or methanol, and thoroughly mixed using a shaking mixer or a V-type mixer. Then, the solvent is distilled off using a drying apparatus, such as a conical drying apparatus, in order to obtain a mixed niobium powder containing a binder. The obtained mixed powder is loaded into the loading hopper of the automatic molding device, weighed when the powder flows through the inlet pipe from the loading hopper into the automatic molding device, which causes the molding device to drop spontaneously into the metal mold and pressed with lead wire. After removing the binder, such a molded article is sintered at a temperature of from 500 to 2000 ° C. under reduced pressure in order to obtain a sintered niobium material.

The sintered niobium material is subjected to electrochemical treatment, for example, in an electrolyte solvent such as phosphoric acid and adipic acid, at a concentration of 0.1 wt.% At a temperature of 30 to 90 ° C at a voltage of 20 to 60 V for 1 hour up to 30 hours with the formation of a dielectric layer, including mainly niobium oxide. A layer of solid electrolyte, for example, such as manganese dioxide, lead dioxide and an electrically conductive polymer, and a graphite layer and a silver paste layer are formed on the dielectric layer. After the cathode terminal is connected by curing, everything is poured with resin, thereby obtaining a solid electrolyte capacitor.

In the event that a powder is used that does not have a suitable fluidity or a suitable angle of repose, the powder flows unevenly from the loading hopper into the automatic molding device, which does not allow stable molding of the products. In particular, since the mixed powder is transported from the loading hopper using a process such as vibration, too high or too low bulk density or average particle size of the mixed powder leads to a large dispersion in the mass of the molded products or in the strength or size of the sintered material, and in some cases leads to chip formation and cracking, resulting in poor leakage current characteristics. Thus, bulk density, average particle size, fluidity and angle of repose for a mixed powder are important factors necessary to obtain a sintered material and capacitor with good characteristics.

The indicated physical properties of the mixed powder almost do not change for the powder before and after mixing with the binder, but are determined by the physical properties of the used niobium powder for capacitors. Accordingly, important characteristics are bulk density, average particle size, fluidity and angle of repose for the mixed powder. The fluidity and angle of repose of the niobium powder are significantly affected by bulk density or average particle size, and therefore, bulk density and average particle size become important factors.

In accordance with the present invention, in order to increase the productivity and strength of the sintered powder in combination with optimizing the yield strength or angle of repose and achieving the effect of reducing the leakage current, the bulk density is preferably from 0.5 to 2.5 g / ml, more preferably from 0, 8 to 1.9 g / ml. The average particle size of the niobium powder of the present invention is preferably from 10 to 1000 microns, more preferably from 50 to 200 microns.

In order for the niobium powder to spontaneously flow out (fall) from the hopper into the metal mold of the molding device, the repose angle of the niobium powder of the present invention is preferably from 10 ° to 60 °, more preferably from 10 ° to 50 ° .

A niobium powder having the physical properties described above can be obtained from a mixture (hereinafter referred to as the “initial mixture of substances”) containing niobium powder or a powder of the niobium compound (hereinafter referred to as “the original niobium powder”) and an activator ( hereinafter referred to as a "pore-forming substance", and also sometimes hereinafter sometimes referred to as an "additive") by at least sequentially carrying out a sintering step and a crushing step.

The activator is removed either at the sintering stage or at the crushing stage upon receipt of the niobium powder, which is the subject of the present invention, from the initial mixture of substances. The removal of the activator can also be carried out independently of the sintering stage or the crushing stage.

Various methods can be used to remove the activator in accordance with the chemical properties of the activator.

Various methods for removing the activator include a method of evaporation, sublimation or thermal decomposition of the activator and its removal in the form of gas, as well as a method of removing the activator by dissolving it in any solvent.

In the case of removal of the activator in the form of a gas, the removal can be carried out at the sintering stage, or the stage of removal of the activator by heating and / or under reduced pressure can be carried out before sintering.

If the activator is removed by dissolving it in a solvent after sintering the initial mixture of substances, either during the process or after crushing, the solvent described below is brought into contact with the sintered material or crushed product, dissolving and removing the activator.

Partial nitriding, partial boronation, partial carbonization, or partial sulfidation reactions to niobium powder can be carried out at any stage of the method for producing niobium powder, which is the subject of the present invention, from the initial mixture of substances.

A method for producing a niobium powder according to the present invention is described in detail below.

The starting niobium powder may be at least one powder selected from niobium, niobium hydride, niobium alloy and niobium hydride alloy. A portion of this powder may be nitrided, sulfidated, carbonized or borated. The term "alloy" as used in the description of the present invention includes a solid solution with other components of the alloy.

The average particle size of the starting niobium powder is preferably from 0.01 to 10 μm, more preferably from 0.02 to 5 μm, even more preferably from 0.05 to 2 μm.

Examples of a method for producing a niobium material used as a starting niobium powder include a method for hydrogenating, powdering and dehydrogenating a niobium ingot, niobium granules or niobium powder, a method for reducing potassium fluorobiobate with sodium or the like, and grinding the reduction product into powder, a reduction method niobium oxide using at least one substance selected from hydrogen, carbon, magnesium and aluminum, and grinding the product restored Nia and method of reduction with hydrogen halide of niobium.

Examples of a method for producing niobium hydride used as a starting niobium powder include a method for hydrogenating and pulverizing a niobium ingot, niobium granules or niobium powder.

Examples of a method for producing a niobium hydride alloy used as a starting niobium powder include a method of pulverizing an ingot of a product of hydrogenation of a niobium alloy, niobium alloy granules or niobium alloy powder. Examples of the preparation of a niobium alloy used as a starting niobium powder include a method for dehydrogenating a niobium hydride alloy obtained as described above.

An niobium alloy or an alloy of niobium contains, as a component of an alloy other than niobium, at least one element selected from the group consisting of elements having atomic numbers from 88 or lower, with the exception of hydrogen, nitrogen, oxygen, fluorine, chlorine , bromine, iodine, niobium, helium, neon, krypton, argon, xenon and radon.

An activator is a substance that can be removed at any stage of the method for producing the niobium powder according to the present invention from an initial mixture of substances. In the niobium powder of the present invention, pores are usually formed in the part from which the activator is removed.

The particle size of the activator affects the pore diameter of the niobium powder of the present invention, the pore diameter of the niobium powder affects the pore diameter of the sintered niobium material, and the pore diameter of the sintered niobium material affects the capacitance of the capacitor and the impregnating ability of the cathode agent at the stage of manufacturing the capacitor.

The impregnating ability of the cathode agent is of great importance for obtaining a capacitor with a large capacity, as well as with a low ESR characteristic. Since the sintered niobium material is obtained by molding the niobium powder under pressure, the pore diameter of the sintered niobium material is naturally smaller than the pore diameter of the niobium powder. Considering the difficulty of introducing a cathode agent into a sintered niobium material obtained from a niobium powder with a small pore diameter, the average pore diameter of the niobium powder is preferably 0.5 μm or more and more preferably 1 μm or more.

The average pore diameter of said niobium powder is preferably 0.01 to 500 microns, more preferably 0.03 to 300 microns, even more preferably 0.1 to 200 microns. In order for the pore diameter to be in this range, the average particle size of the activator is preferably 0.01 to 500 μm, more preferably from 0.03 μm to 300 μm, even more preferably from 0.1 to 200 μm.

The average pore diameter of the niobium powder is most preferably 0.5 to 100 μm, and the average particle size of the activator is most preferably 0.5 to 100 μm.

The pore diameter can be reduced by using an activator having a small particle size, and the pore diameter can be increased by using an activator having a large particle size.

The distribution of pore diameters can be adjusted by adjusting the particle size distribution of the activator.

In order to obtain a capacitor having a sufficiently high capacity, the manufacture of which does not cause problems associated with the impregnating ability of the cathode agent, preferably in the sintered niobium material in an appropriate manner, in accordance with the physical properties of the cathode agent, to ensure the presence of pores sufficiently small to to achieve the desired capacity, and large enough to ensure satisfactory impregnation of the cathode agent.

In order to regulate the pore diameter distribution of niobium powder or sintered niobium material, for example, in order to obtain niobium powder, in the distribution of pore diameters of which there are two or more maximums, an activator (powder) with a particle size distribution can be used, in which has two or more maximums. By sintering such a powder, a sintered niobium material can be obtained in which there are two or more maximum equivalent pore diameters in the distribution of pore diameters. In this case, the maximum pore diameter is preferably in the range from 0.01 to 500 microns, more preferably from 0.03 to 300 microns, even more preferably from 0.1 to 200 microns and most preferably from 0.2 to 3 microns.

The niobium powder for producing such a sintered niobium material, as described above, has two or more maximums in the particle size distribution. Any one of two or more maxima corresponds, preferably, 0.5 microns or more. For example, in order to obtain a sintered niobium material that has two peaks in the particle size distribution at 0.7 and 3 μm, niobium powder with two peaks at about 1.5 and about 25 μm can be selected. In order to obtain a niobium powder having pores of a small diameter of 1.5 μm and pores of a large diameter of 25 μm, it is necessary, respectively, to use an activator with an average pore diameter of 1.5 μm and 25 μm. As a rule, when there are pores of small diameter and pores of large diameter in the niobium powder, the largest diameter decreases during molding under pressure. Therefore, the maximum for the larger diameter is preferably 20 μm or more. Also preferably, 30 vol.% Or more of the total pore volume has a diameter of 20 μm or more, and more preferably 40 vol.% Or more.

The above example is illustrated in detail in the drawings. Figure 1 in an enlarged view schematically shows the niobium powder, which is the subject of the present invention. The niobium powder shown in FIG. 1 is a granular powder comprising an initial powder that contains pores of a certain diameter formed by an activator. Pores (A) and (B) are formed using an activator having an average diameter of approximately 1.5 μm and approximately 25 μm, respectively. Thus, it is possible to efficiently agglomerate the primary powder. Figure 2 shows the pore size distribution curve for niobium powder obtained by mercury porosimetry. The maximum (A) represents the maximum corresponding to the pores (A) formed by the activator having an average diameter of approximately 1.5 μm, and the maximum (B) represents the maximum corresponding to the pores (B) formed by the activator having an average diameter of approximately 25 μm respectively. The maximum (B) is higher than the maximum (A), and 44% of the total pore volume have a diameter of 20 μm or more.

An activator, in the distribution of which according to the particle size there are two or more maximums, can be obtained, for example, by mixing two or more activators having different maxima in the distribution of particle sizes.

Examples of compounds used as an activator include a compound that is converted to gas at a sintering temperature or lower, and a compound that is soluble in any solvent at least after sintering.

Examples of compounds that are converted to gas at a sintering temperature or lower include compounds that are converted to gas by evaporation, sublimation or thermal decomposition. Preferred are inexpensive compounds capable of being easily converted to gas even at low temperature without leaving a residue. Examples of such compounds include aromatic compounds such as naphthalene, anthracene and quinone, camphor, NH ₄ Cl, ZnO, WO ₂ , SnO ₂ and MnO ₃ and organic polymers.

Examples of organic polymers include polyacrylic acid, acrylic acid ester polymer, polyacrylamide, polymethacrylic acid, methacrylic acid ester polymer, polymethacrylamide and polyvinyl alcohol.

A substance that is soluble in any solvent at least after sintering is a substance such as an activator residue or a thermal decomposition product of an activator soluble in any solvent. A substance capable of easily dissolving in a solvent, which is described later, after sintering or during grinding or after grinding, is particularly preferred. Such a substance may be selected from many compounds in accordance with a combination with a solvent.

Examples of such compounds include metal compounds with carboxylic acid, sulfuric acid, sulfuric acid, halogen, perhalogen acid, hypohalogen acid, nitric acid, nitrous acid, phosphoric acid, acetic acid, oxalic acid or boric acid, and metal oxides, metal hydroxides and metals.

Among these compounds, preferred are those which exhibit good solubility in solvents such as acid, alkali or ammonium salt solutions, which are described below. Examples of such compounds include at least one compound selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, France, beryllium, magnesium, calcium, strontium, barium, radium, scandium, yttrium, cerium, neodymium, erbium, titanium, zirconium, hafnium, vanadium, niobium, tantalum, molybdenum, tungsten, manganese, rhenium, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, silver, gold, zinc, cadmium, aluminum, gallium, indium, thallium, Germany, tin, lead, antimony, bismuth, selenium, tellurium, polonium, boron, silicon and arsenic. Among these compounds, metal salts are preferred and, for example, barium oxide, manganese (II) nitrate and calcium carbonate are more preferred.

These activators can be used individually or in combination of two or more activators.

In order to efficiently form a specific pore size, it is preferable to use a compound that is in the solid state at the sintering temperature as an activator substance. The reason for this is that the activator, which is in the solid state, prevents excessive agglomeration of the initial niobium powder and makes it possible to fuse the niobium powder only at the point of contact of the powder particles with each other. If the activator at the sintering temperature is in the form of a liquid or gas, this will have a negligible effect on such agglomeration and can lead to the formation of pores of smaller size than necessary. Therefore, the pore diameter becomes more stable if the activator includes a substance with a higher melting point, for example, such as barium oxide, calcium carbonate, aluminum oxide and magnesium oxide, compared with an activator that includes a substance with a lower melting point for example, such as metallic aluminum, metallic magnesium, magnesium hydride and metallic calcium. If the activator is added in a small amount, the bulk density and angle of repose become larger, while if the activator is added in a significant amount, the bulk density becomes small, and the number of closed pores increases at the sintering stage. In order to obtain a slope angle of 60 ° or less and a bulk density of 0.5 to 2.5 g / ml, without the problem of the occurrence of closed pores at the sintering stage, the amount of activator added is usually from 1 to 40 wt.% or less (unless otherwise indicated, hereinafter, wt.% are simply indicated as%), preferably from 5 to 25%, more preferably from 10 to 20%, based on the original niobium material, although these values vary depending from the average particle size of the activator. A mixture of starting materials can be obtained by mixing the activator and the starting niobium material, each of which is in powder form, without using a solvent, or by mixing the activator and the starting niobium material using a suitable solvent and drying the mixture. Examples of solvents that can be used include water, alcohols, ethers, cellosolves, ketones, aliphatic hydrocarbons, aromatic hydrocarbons and halogenated hydrocarbons. Mixing can be carried out using a mixer. Conventional apparatuses, such as a shaking mixer, a V-type mixer or a Nauter mixer, can be used as a mixer without any problems. The mixing temperature is limited by the boiling point and the freezing point of the solvent, but, as a rule, is from -50 ° C to 120 ° C, preferably from -50 ° C to 50 ° C, more preferably from -10 ° C to 30 ° C.

The time taken for mixing is practically unlimited, to such an extent that the time taken is 10 minutes or more, however, the mixing is usually carried out for 1 to 6 hours, preferably in an oxygen-free atmosphere using an inert gas, such as nitrogen or argon.

In the case of using a solvent, the resulting mixture is dried at a temperature lower than 80 ° C, preferably lower than 50 ° C, using a conical drying apparatus or a drying chamber. When the mixture is dried at a temperature of 80 ° C or higher, the amount of oxygen contained in the niobium powder or in the powder of niobium hydride increases, which is undesirable.

In the case where the activator is converted to gas at a sintering temperature or lower, the activator can be removed during sintering, however, the step of converting the activator into gas and its removal before sintering can be carried out independently by adjusting conditions such as temperature, pressure and time period, so that these conditions contribute to the removal of the activator in accordance with its chemical properties. In this case, the activator is evaporated, for example, at a temperature of from 100 ° C to 800 ° C under reduced pressure for several hours.

When using niobium hydride or a niobium hydride alloy as the starting niobium material, dehydrogenation can be achieved regardless of the type of activator by carrying out the steps described above.

The sintering step is carried out at a temperature of from 500 ° C to 2000 ° C, preferably from 800 ° C to 1500 ° C, more preferably from 1000 ° C to 1300 ° C, under reduced pressure or in a reducing atmosphere, such as an argon atmosphere. After sintering is completed, the sintering product is preferably cooled until the temperature of the niobium material (sometimes simply referred to as “product temperature”) becomes 30 ° C or less, an inert gas such as nitrogen or argon containing from 0.01 vol. % to 10 vol.%, preferably from 0.1 vol.% to 1 vol.% oxygen, so that the temperature of the product does not exceed 30 ° C, and after holding for 8 hours or more, the sintered product is removed, receiving at this sintered mass.

At the crushing stage, the sintered mass is crushed to particles of a suitable size using a crushing plant such as a roller mill.

In the case when the activator is soluble in any solvent at least after the sintering step, a suitable solvent is brought into contact with the sintered mass or crushed powder, after sintering or before crushing, during crushing or after crushing, or when performing many such steps, wherein the activator component is dissolved and removed. Considering the ease of removal, the activator component is preferably dissolved and removed from the crushed powder after crushing.

The solvent used for this is preferably a solvent in which the activator to be dissolved has sufficiently good solubility. A solvent is preferred which is inexpensive and does not remain in the product. For example, in the case of a water-soluble activator, water may be used; in the case of an activator soluble in an organic solvent, an organic solvent such as methyl isobutyl ketone, ethanol or dimethyl sulfoxide (DMSO) may be used; in the case of an acid soluble activator, an acid solution such as nitric acid, sulfuric acid, phosphoric acid, boric acid, carboxylic acid, hydrofluoric acid and hydrochloric acid, hydrobromic acid, hydroiodic acid or organic acid can be used; in the case of an alkali soluble activator, an alkaline solution may be used, such as a solution of an alkali metal hydroxide, an alkaline earth metal hydroxide or ammonium; when the activator forms a soluble complex, an amine solution such as ammonia or ethylenediamine, an amino acid solution such as glycine, a polyphosphoric acid solution such as sodium tripolyphosphate, a crown ether solution, a thiosulfate solution such as sodium thiosulfate can be used. or a solution of a complexing agent, such as ethylenediaminetetraacetic acid, which becomes the ligand of the complex.

An ammonium salt solution such as ammonium chloride, ammonium nitrate and ammonium sulfate, a cation exchange resin and anion exchange resin can also be suitably used. It is preferable to dissolve and remove the activator at a low temperature. In the case when the activator is dissolved and removed at high temperature, the surface of the niobium material becomes oxidized, since niobium is characterized by a high affinity for oxygen. Therefore, the temperature of dissolution and removal is preferably 50 ° C or lower, more preferably from -10 ° C to 40 ° C and even more preferably from 0 to 30 ° C. In accordance with the above reasons, it is preferable to choose a method that leads to slight heating during dissolution and removal. For example, in the case when a metal oxide or metal is used as an activator, dissolution and removal using an acid results in the release of a significant heat of neutralization. Thus, it is preferable to choose a method that leads to insignificant heat, for example, such as dissolving in water and in an organic solvent, the formation of a soluble complex, as when using a solvent - salts of ammonium nitrate, and ethylenediaminetetraacetate, and such a method as dissolving in a solvent, containing ion exchange resin.

Specific examples of the combination of activator and solvent include barium oxide and water, calcium oxalate and hydrochloric acid, aluminum oxide and an aqueous solution of sodium hydroxide, hafnium oxide and methyl isobutyl ketone, magnesium carbonate and an aqueous solution of tetra sodium salt of ethylene diamine tetra acetate.

After dissolving and removing the activator, the residue is thoroughly washed and dried. For example, in the case where barium oxide is removed using water, the residue is washed thoroughly using a solution purified by ion exchange until the conductivity of the washing solution decreases to 5 μS / cm or less. The product is then dried at a temperature of 50 ° C or less under reduced pressure. In this case, the amount of residual activator or solvent component is usually 100 parts by weight. per million or less, although this value varies depending on the washing conditions.

In order to increase the LC performance, the niobium powder thus obtained, the sintered mass and the starting niobium powder are partially nitrided, borated, carbonized or sulfidized, or a combination of such treatments.

The niobium powder of the present invention may contain the obtained niobium nitride, niobium boride, niobium carbide and niobium sulfide, or various combinations of such substances. The total content of the corresponding elements - nitrogen, boron, carbon and sulfur varies depending on the shape of the niobium powder, however, this amount is from 0 to 200,000 parts by weight. per million, preferably from 50 to 100,000 parts by weight per million, more preferably from 200 to 20,000 parts by weight per million. If the total content exceeds 200,000 parts by weight, the characteristics of the capacitance deteriorate, and the manufactured capacitor is not suitable as a capacitor.

Nitriding of niobium powder can be carried out by any of the following methods: liquid-phase nitriding, ion nitriding and gas-phase nitriding, or by combining these methods. Among these methods, gas-phase nitriding in an atmosphere of gaseous nitrogen is preferable because the apparatus for this is quite simple and the method is easy to implement. For example, gas phase nitriding in a nitrogen gas atmosphere can be achieved by holding the above niobium powder in a nitrogen gas atmosphere. When nitriding, the temperature of the gaseous medium is 2000 ° C or less, and the exposure time is 100 hours or less, while niobium powder with the required degree of nitriding can be obtained. Processing time can be shortened by processing at a higher temperature.

Boronation of niobium powder can be carried out either by gas phase boronation or by solid phase boronation. For example, niobium powder can be boronated by exposure to a boron source, such as boron granules or boron halide (e.g., trifluoroboride), at 2000 ° C. or less for 1 minute to 100 hours under reduced pressure.

Carbonization of niobium powder can be carried out by any of the following methods: gas phase carbonization, solid phase carbonization and liquid phase carbonization. For example, niobium powder can be carbonized by exposure to a carbon source, such as a carbon material or an organic substance containing carbon (such as methane), at 2000 ° C or less for 1 minute to 100 hours under reduced pressure .

Sulphidation of niobium powder can be carried out by any of the following methods: gas phase sulfidation, ionic sulfidation and solid phase sulfidation. For example, gas phase sulphidation in an atmosphere of sulfur gas can be carried out by holding the niobium powder in the atmosphere for sulphidation. At a medium temperature for carrying out sulfidation equal to 2000 ° C. or less, and a holding time of 100 hours or less, a niobium powder having the desired degree of sulfidation can be obtained. Processing time can be shortened if the process is carried out at a higher temperature.

The specific surface, determined by the adsorption isotherms by the Braunauer-Emet-Teller method (BET surface), is from 0.5 to 40 m ² / g, preferably from 0.7 to 10 m ² / g, more preferably from 0.9 to 2 m ² / g.

The niobium powder of the present invention can be a mixture of niobium powders, different in bulk density, particle size, angle of repose, specific BET surface, pore diameter distribution and type of processing by nitriding, boronation, carbonization or sulfidation.

Sintered material, which is the subject of the present invention, which can be used as an electrode for capacitors, is preferably obtained, for example, by sintering the niobium powder described above according to the present invention. For example, the sintered material can be obtained by molding when pressing the niobium powder in a predetermined form and subsequent heating at a temperature of from 500 ° C to 2000 ° C, preferably from 800 ° C to 1500 ° C, more preferably from 1000 ° C to 1300 ° C, for 1 minute to 10 hours at a pressure of 10 ^-5 to 10 ² Pa.

In the distribution of pore diameters of the sintered material obtained from the niobium powder of the present invention, there is usually a maximum pore diameter in the range from 0.01 μm to 500 μm.

As a result of adjusting the pressure applied during molding to a specific value, the sintered material may have a larger number of maxima in the distribution of pore diameter than niobium powder. The above value of the applied pressure varies depending on the molding characteristics during compression, such as the physical properties of the niobium powder, the size of the molded product, and depending on the pressing device used, but is in the range from the pressure at which it is possible to perform molding by pressing, to pressure in which the pores of the sintered material are not closed. The preferred pressure value can be determined by preliminary experiments to determine the appropriate conditions, such as the physical properties of the niobium powder used for molding, so as to obtain several peaks in the distribution of pore size. The magnitude of the applied pressure can be controlled, for example, by monitoring the load applied to the molded product in the molding device.

The pore size distribution of the sintered material preferably contains at least two pore size maxima so that pores are formed that are small enough to reach the required capacity and large enough to ensure satisfactory impregnation by the cathode agent in accordance with physical properties cathode agent. From such a sintered material having several peaks in the distribution along the pore diameter, a capacitor can be obtained having excellent impregnating ability in the formation of the counter electrode and a high degree of capacity realization.

In the case when the distribution of pore diameters has a large number of maxima, and the maxima of the two peaks with the highest relative efficiency are in the range from 0.2 μm to 0.7 μm and in the range from 0.7 μm to 3.0 μm, respectively preferably in the range from 0.2 μm to 0.7 μm and from 0.9 μm to 3 μm, respectively, a capacitor made of such sintered material may have good moisture resistance. A condenser may have better moisture resistance if the distribution of pore diameters among a large number of pore diameter maxima contains a maximum with the highest relative intensity, which is in the region of larger diameters than the maximum with the next relative intensity.

The specific surface area of the material thus obtained is typically from 0.2 m ² / g to 7 m ² / g.

Usually, the larger the volume of sintered material, the more difficult is its impregnation with a counter electrode. For example, in the case where the sintered material has a volume of 10 mm ³ or more, the sintered material of the present invention, having a large number of maxima in the distribution along the pore diameter, can be used particularly effectively.

The sintered material of the invention may be partially nitrided. As regards nitriding methods, the methods described above for nitriding niobium powder can be used. It is also possible to nitrate a portion of the niobium powder intended for the manufacture of sintered material, and to nitrate a portion of the sintered material made from this niobium powder.

Such sintered material usually contains from 500 to 70,000 parts by weight. per million oxygen, because there is oxygen of natural oxidation contained in the niobium powder before sintering, and oxygen of natural oxidation after sintering is added to this amount. In the sintered material that is the subject of the present invention, the content of elements, with the exception of niobium, elements forming the alloy, as well as oxygen and nitrogen, is usually 400 parts by weight per million or less.

For example, in the case when the sintered material of the present invention is sintered at 1300 ° C, the CV value (for the product of electrochemical molding when applying electric voltage during electrochemical molding at 80 ° C for 120 minutes in 0.1 wt. % aqueous solution of phosphoric acid and electric capacitance at 120 Hz) is from 40,000 to 200,000 μFV / g.

A description of the manufacturing process of the capacitor device is given below.

For example, a lead wire is prepared comprising a valve metal, such as niobium or tantalum, and having an appropriate volume and length, and this lead wire as a whole is pressed into a pressurized niobium powder pressing device so that a part of the lead wire is inside the formed wire products, and lead wire may come out of the main part of the sintered material. Or, the niobium powder is molded and sintered without using a lead wire, and then a separately made lead wire is attached thereto by welding or the like.

When using such a sintered material as one of the electrodes, a capacitor can be manufactured by placing a dielectric substance between this electrode and the counter electrode. For example, a capacitor is manufactured using a niobium sintered material as a single electrode, forming a dielectric material on the surface of the sintered material (including the inner surface of the pores), and forming a counter electrode on the dielectric material.

The dielectric material used in this case for the manufacture of a capacitor is preferably a dielectric material, mainly including niobium oxide, more preferably a dielectric material, mainly including niobium pentoxide. A dielectric material, mainly including niobium pentoxide, can be obtained, for example, by electrochemical oxidation of niobium sintered material as a single electrode. For the electrochemical oxidation of a niobium electrode in an electrolyte solution, an aqueous protic acid solution, such as an aqueous 0.1% phosphoric acid solution, an aqueous solution of sulfuric acid, an aqueous 1% acetic acid solution or an adipic acid aqueous solution, is usually used. In the case of obtaining a dielectric material - niobium oxide by electrochemical formation of a niobium electrode in an electrolyte solution, essentially the capacitor of the present invention is an electrolyte capacitor, and the niobium electrode serves as an anode.

In the capacitor which is the subject of the present invention, the choice of the counter electrode with respect to the sintered niobium material is not particularly limited and, for example, at least one material (compound) selected from solutions of electrolyte, organic and inorganic semiconductors known from the prior art can be used. for aluminum capacitors with electrolyte.

Specific examples of the electrolyte solution include a mixed dimethylformamide-ethylene glycol solution containing 5 wt.% Of the dissolved electrolyte - isobutyltropropylammonium boron tetrafluoride, a mixed propylene carbonate-ethylene glycol solution containing 7 wt.% Of the dissolved electrolyte - boron tetraethylammonium tetrafluoride.

Specific examples of an organic semiconductor include an organic semiconductor comprising a benzopyrroline tetramer and chloranil, an organic semiconductor mainly comprising tetratiotetracene, an organic semiconductor mainly comprising tetracyanoquinodimethane, and an electrically conductive polymer containing a repeating unit represented by the following formulas (1) and (2):

in which the radicals from R ¹ to R ⁴ each independently represent a monovalent group selected from the series containing a hydrogen atom, a linear or branched, saturated or unsaturated alkyl, alkoxy or alkyl substituted ester group containing from 1 to 10 carbon atoms, a halogen atom a nitro group, a cyano group, a primary, secondary or tertiary amino group, a CF ₃ group, a phenyl group or a substituted phenyl group; each of the pairs R ¹ and R ² , R ³ and R ⁴ can be combined arbitrarily with the formation of a bivalent chain to obtain at least one 3-, 4-, 5-, 6- or 7-membered saturated or unsaturated cyclic hydrocarbon structure together with carbon atoms substituted by radicals R ¹ and R ² or radicals R ³ and R ⁴ ; the combined cyclic chain may contain a bond with a carbonyl, ether group, ester group, amide group, sulfide group, sulfinyl, sulfonyl or iming group in an arbitrary position; X represents an oxygen atom, a sulfur atom or a nitrogen atom; R ^{5 is} present only when X represents a nitrogen atom, and independently represents a hydrogen atom or a linear or branched, saturated or unsaturated alkyl group containing from 1 to 10 carbon atoms.

In accordance with the present invention, in the formula (1) or (2), the radicals R ¹ to R ⁴ each independently preferably represent hydrogen, a linear or branched, saturated or unsaturated alkyl or alkoxy group containing from 1 to 6 carbon atoms, and each of the pairs R ¹ and R ² , R ³ and R ⁴ may combine to form a ring.

In accordance with the present invention, an electrically conductive polymer comprising a repeating unit represented by formula (1) is preferably an electrically conductive polymer whose repeating unit is represented by the following formula (3):

in which R ¹ and R ² each independently represents a hydrogen atom, a linear or branched, saturated or unsaturated alkyl group containing from 1 to 6 carbon atoms, or a substituent capable of forming at least one 5-, 6- or 7-membered saturated a cyclic hydrocarbon structure containing two oxygen moieties derived from alkyl groups that combine with each other in an arbitrary position; the cyclic structure includes a structure containing a vinylene bond, which may be substituted, and a phenylene structure, which may be substituted.

A dopant is introduced into an electrically conductive polymer having the indicated chemical structure, which can be any known dopants.

Specific examples of the inorganic semiconductor are mainly an inorganic semiconductor including lead dioxide or manganese dioxide, and an inorganic semiconductor including ferric tetraoxide. These semiconductors can be used individually or in combination of two of them or more.

Examples of a polymer containing a repeating unit that is represented by formula (1) or (2) include polyaniline, polyoxyphenylene, polyphenylene sulfide, polythiophene, polyfuran, polypyrrole, polymethylpyrrole and their substituted derivatives and copolymers. Among these substances, polypyrrole, polythiophene and their substituted derivatives (e.g. poly (3,4-ethylenedioxythiophene)) are preferred.

In the case when the used organic or inorganic semiconductors have an electrical resistance of from 10 ^-2 S / cm to 10 ³ S / cm, the manufactured capacitor has a lower impedance and its capacitance at high frequencies can be increased.

A layer of an electrically conductive polymer is formed, for example, by polymerization of a polymerizable compound, such as aniline, thiophene, furan, pyrrole, methylpyrrole or their substituted derivatives, when exposed to an oxidizing agent capable of satisfactorily undergoing an oxidation reaction - dehydrogenating two-electron oxidation. Examples of the polymerization reaction of the polymerizable compound (monomer) include vapor polymerization and solution polymerization. A layer of conductive polymer is formed on the surface of the sintered niobium material on which there is a dielectric material. In the case where the electrically conductive polymer is an organic solvent-soluble polymer suitable for coating from a solution in order to form a layer of an electrically conductive polymer, a method for producing a polymer coating on the surface of a sintered material is used.

One preferred example of a manufacturing process using solution polymerization is a method of immersing a sintered niobium material on which there is a layer of dielectric material in a solution containing an oxidizing agent (solution 1), and then immersing the sintered material in a solution containing monomer and dopant (solution 2) during polymerization, in order to form a layer of an electrically conductive polymer on the surface of the sintered material. Also, the sintered material can be immersed in solution 1 after it has been immersed in solution 2. As a solution 2 used in accordance with the method described above, a dopant-free monomer solution can be used. In the case of using dopant, the latter may be in solution together with an oxidizing agent.

The operation of carrying out such polymerization stages is repeated once or more, preferably from 3 to 20 times, using sintered niobium material on which there is a dielectric material, and a dense and layered layer of an electrically conductive polymer can easily be formed.

In accordance with the manufacturing method of the capacitor according to the present invention, any oxidizing agent can be used if it does not adversely affect the performance of the capacitor, and the oxidizing agent reducing agent can deplete the dopant and increase the conductivity of the electrically conductive polymer. Preferred for use is an inexpensive commercially available compound that is easy to work with.

Specific examples of oxidizing agents include Fe (III) -based compounds such as FeCl ₃ , FeClO ₄ and Fe salts (organic anion); anhydrous aluminum chloride / copper chloride (I); alkali metal persulfates; ammonium persulfate, peroxides; manganese compounds such as potassium permanganate; quinine derivatives such as 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDC), tetrachloro-1,4-benzoquinone and tetracyano-1,4-benzoquinone; halogens such as iodine and bromine; peracids; sulfonic acids such as sulfuric acid, fuming sulfuric acid, sulfur trioxide, chlorosulphuric acid, fluorosulphuric acid and amidosulphuric acid, and mixtures of these oxidizing agents.

Examples of the most typical compounds with an organic acid anion for the formation of the Fe salts described above (organic anion) include organic sulfonic acids, organic carboxylic acids, organic phosphoric acids and organic boric acids. Specific examples of organic sulfonic acids include benzenesulfonic acid, n-toluenesulfonic acid, methanesulfonic acid, ethanesulfonic acid, α-sulfonaphthalene, β-sulfonaphthalene, naphthalene disulfonic acid and alkylnaphthalene sulfonic acid (examples of alkyl include butyl, triisopropyl and di-butyl).

Specific examples of organic carboxylic acids include acetic acid, propionic acid, benzoic acid and oxalic acid. In addition, anions of polymer electrolytes such as polyacrylic acid, polymethacrylic acid, polystyrenesulfonic acid, polyvinyl sulfonic acid, poly-α-methyl sulfonic acid, polyvinyl sulfuric acid, polyethylene sulfonic acid and polyphosphoric acid can also be used in accordance with the present invention. These organic sulfonic acids and organic carboxylic acids are given only as an illustration of the invention, and the present invention is not limited to them. Examples of the counterion for the anions described above include alkali metal ions such as H ⁺ , Na ⁺ and K ⁺ , as well as ammonium ions substituted with a hydrogen atom, tetramethyl group, tetraethyl group, tetrabutyl group or tetraphenyl group, however, the present invention is not limited to this. Among these oxidizing agents, oxidizing agents are preferred including ferric iron compounds, copper (I) chloride, alkali metal persulfate, ammonium persulfate or quinone.

As an anion which has the property of a dopant and which may be present together, if necessary, in the manufacture of a polymer composition for an electrically conductive polymer (an anion other than an anion reducing agent of an oxidizing agent), an electrolyte anion containing an anion of an oxidizing agent as a counterion can be used (an oxidizing agent reducing agent) produced by the oxidizing agent described above, or another electrolyte anion. Specific examples of such anions include protic acid anions, including group 5B halide anions such as PF ₆ ^- , SbF ₆ ^- , PF ₆ ^- and AsF ₆ ^- , group 3B group halide anions such as BF ₄ ^- ; halogen anions such as I ^- (I ^3- ), Br ^- and Cl ^- ; a perhalogenate anion such as ClO ₄ ^- , a Lewis acid anion such as AlCl ₄ ^- , FeCl ₄ ^- , SnCl ₅ ^- , an inorganic acid anion such as NO ₃ ^- and SO ₄ ^2- ; a sulfonate anion, such as the anion of n-toluenesulfonic acid, naphthalenesulfonic acid and the anion of an alkyl substituted naphthalenesulfonic acid containing from 1 to 5 carbon atoms (hereinafter referred to simply as “C1-5”); organic sulfonate anions such as CF ₃ SO ₃ ^- and CH ₃ SO ₃ ^- ; and carboxylate anions such as CH ₃ COO ^- and C ₆ H ₅ COO ^- .

Other examples include anions of polymer electrolytes such as polyacrylic acid, polymethacrylic acid, polystyrenesulfonic acid, polyvinyl sulfonic acid, polyvinyl sulfuric acid, poly-α-methyl sulfonic acid, polyethylene sulfonic acid and polyphosphoric acid. However, the present invention is not limited to this. Among these anions, high molecular weight or low molecular weight anions of organic sulfonic acid or polyphosphoric acid are preferred. Preferably, derivatives of aromatic sulfonic acid (e.g., sodium dodecylbenzosulfonate, sodium naphthalene sulfonate) are used as anion-forming compounds.

Among organic sulfonate anions, more effective dopants are sulfoquinone derivatives, in the molecule of which there is one or more sulfoanionic groups (-SO ₃ ^- ) and which have a quinone structure, as well as anthracene sulfonate anion.

Typical examples of the skeleton of the sulfoquinone anion of the above sulfoquinone derivatives include p-benzoquinone, o-benzoquinone, 1,2-naphthoquinone, 1,4-naphthoquinone, 2,6-naphthoquinone, 9,10-anthraquinone, 1,4-anthraquinone, 1,2 -anthraquinone, 1,4-chrysenquinone, 5,6-chrysenquinone, 6,12-chrysenquinone, acenaphthoquinone, acenaphthenoquinone, camphoroquinone, 2,3-boronandion, 9,10-phenanthrenquinone and 2,7-pirenoquinone.

In the case where the counter electrode is solid, an electrically conductive layer can be formed on it so as to achieve good electrical contact with the outer lead wire (e.g., lead frame), which is used if necessary.

An electrically conductive layer may be formed, for example, by curing the electrically conductive paste, cladding, metallizing, or forming a film of a heat-resistant electrically conductive polymer. Preferred examples of the electrically conductive paste include silver paste, copper paste, aluminum paste, carbon paste and nickel paste, these pastes can be used individually or in combination of two or more pastes. In the case of using two or more kinds of pastes, pastes can be mixed or applied alternately on top of each other in separate layers. The applied electrically conductive paste is then cured by holding it in air or by heating. Examples of cladding include nickel cladding, silver cladding and aluminum cladding. Examples of metals from which the vapor deposited film is formed include nickel, copper, and silver.

More specifically, for example, carbon paste and silver paste are applied in the indicated order to the second electrode and pressed with a material such as, for example, epoxy resin, thereby obtaining a capacitor. This capacitor may contain lead with the addition of niobium or tantalum, which is sintered and molded as a whole with sintered niobium material or welded later.

The capacitor made in this way, which is the subject of the present invention, is used in a closed casing, for example, a polymer melt, a surface polymer shell, a metal casing, an immersed polymer film or a laminating film are used, and then used as a finished condenser product - for various purposes.

In the case where the counter electrode is liquid, the capacitor manufactured includes the two electrodes described above and the dielectric material disposed therein, for example, this material can be electrically connected to the counter electrode in order to complete the capacitor. In this case, the electrode side of the sintered niobium material has a lead out through lead with the addition of niobium or tantalum described above, and at the same time, the electrode side is isolated from the housing by insulating with a resin or the like.

By manufacturing the sintered material for the capacitors using the niobium powder obtained in accordance with the present invention described on the previous pages and manufacturing the capacitor from the sintered material, a capacitor having a low leakage current and high reliability can be obtained.

The capacitor of the present invention has a higher capacitance per unit volume than commonly used tantalum capacitors, and thus a more compact capacitor can be manufactured.

A capacitor according to the present invention having the above properties can be used, for example, as a blocking capacitor or as an isolation capacitor, which is often used in analog circuits and in digital circuits, and can also be used in the same way as well-known tantalum capacitors.

As a rule, a capacitor is often used in electronic circuits. In the case where a capacitor is used, which is the subject of the present invention, restrictions on the installation of electronic parts or in connection with the heat generated can be reduced, and therefore an electronic circuit having high reliability can be placed in a small space, which is a necessary requirement presented to conventional electronic circuits.

Moreover, the use of a capacitor according to the present invention allows the manufacture of electronic devices having a smaller size and higher reliability, such as a computer, peripheral computer equipment (e.g., PC Card), mobile devices (e.g., portable telephone), household appliances, equipment, installed on rolling stock, artificial satellites and communications.

Most preferred embodiment of the invention

The present invention is characterized in more detail through the following examples and comparative examples, but is not limited to them.

In each of the examples, bulk density, angle of repose, particle size and pore diameter of niobium powder, capacitance, leakage current, degree of capacitance, moisture resistance of the capacitor, and ESR characteristic of the capacitor are measured in accordance with the following methods.

(1) Bulk density measurement

The bulk density is measured in accordance with the methodology for the bulk device using a measuring tool used according to the method for measuring the apparent specific gravity of industrial sodium carbonate described in JIS (Japanese Industrial Standard, Edition 2000) K1201-1.

(2) Measuring the angle of repose

The angle of repose is measured using fluidity measuring equipment and the amount of sample provided for in JIS (Japanese Industrial Standard, Edition 2000) Z2504. More specifically, niobium powder is poured from the loading device onto a horizontal surface from the loading hopper, the lower part of which is 6 cm above the horizontal surface, and the angle of inclination of the surface of the circular cone formed with the horizontal surface is determined, this angle is designated as the angle of repose.

(3) particle size measurement

Using apparatus manufactured by Microtrack (HRA 9320-X100), the particle size distribution was determined using a laser diffraction method. The particle size (D ₅₀ , μm) obtained in the case when the total volume corresponds to 50 vol.%, Is designated as the average particle size.

(4) Measurement of pore diameter

A Poresizer 9320 pore diameter measuring device manufactured by Micromeritics is used; pore size distribution is determined by mercury porosimetry.

In accordance with the present invention, the maximum value is determined depending on the rate of change corresponding to the pressure of the value and by determining the pore diameter corresponding to the largest value, while the maximum intensity value to which the maximum value refers is indicated as the maximum value.

(5) Capacitor Capacitance Measurement

An LCR meter manufactured by Hewlett-Packard is installed between the outputs of the fabricated chip, and a capacitance measured at room temperature at 120 Hz is indicated as the capacitance of a capacitor mounted in the chip.

(6) Capacitor leakage current measurement

The current value measured at a constant voltage of 6.3 V, which is continuously supplied between the outputs of the fabricated chip for 1 minute at room temperature, is determined as the leakage current of the capacitor located in the chip.

(7) Measurement of the degree of capacity realization

Assuming that in the case when the sintered material is subjected to electrochemical molding in an aqueous 0.1% solution of phosphoric acid for 1000 minutes at 80 ° C and 20 V, the capacity when measured in 30% sulfuric acid is 100%, the degree of implementation capacitance is expressed by the ratio of capacitance after the capacitor is manufactured.

(8) Condenser moisture absorption value

The value of the moisture absorption of the condenser is expressed by the number of units corresponding to such a capacity of the manufactured condenser, aged at 60 ° C and 95% relative humidity for 500 hours, the value of which is less than 110% or less than 120% of the original capacity. The greater the number of units corresponding to a capacity of less than 110%, the better the moisture resistance.

(9) Capacitor ESR measurement

An LCR meter manufactured by Hewlett-Packard is installed between the outputs of the manufactured chip and the ESR is measured at room temperature at 100 kHz, 1.5 VDC and 0.5 Vrms, this value is indicated as the ESR of the capacitor,

Example 1

5000 g of potassium fluorniobate, carefully dried at 80 ° C, and sodium in a 10-fold molar excess with respect to potassium fluorobiobate are charged into a crucible made of nickel, and the mixture is kept for 20 hours at 1000 ° C in an argon atmosphere for reduction. After completion of the reaction, the reduction product is cooled, washed successively with water, 95% sulfuric acid and water, dried in a vacuum, and ground for 40 hours in a ball mill with an aluminum container containing aluminosilicate balls. Powdered product is immersed and mixed in a solution of the mixture in a ratio of 3: 2 (by weight) of 50% nitric acid and 10% aqueous hydrogen peroxide. After that, the powdered product is thoroughly washed with water until the pH of the water reaches 7 in order to remove impurities, and then dried in vacuum. The starting material, niobium powder, has an average particle size of 1.2 microns.

500 g of this starting material, niobium powder, are loaded into a niobium crucible, and 50 g of butyl polymethyl methacrylate and 1 liter of toluene are added thereto. In addition, zirconia beads are added and the contents are mixed for 1 hour using a shaking mixer. After removal of the zirconium beads, the mixture is placed in a conical drying apparatus and dried in vacuum at a pressure of 1 × 10 ² Pa and 80 ° C.

After that, the niobium powder is heated at a pressure of 1 × 10 ^-2 Pa and a temperature of from 250 to 400 ° C for 12 hours in order to decompose and remove butyl polymethylmethacrylate, and then sintered at 4 × 10 ^-3 Pa at 1150 ° C within 2 hours. The sintered niobium mass is cooled until the product temperature reaches 30 ° C or less, and then crushed using a roller mill, thereby obtaining a crushed niobium powder with a particle size of 100 μm.

The obtained crushed niobium powder is nitrided at 300 ° C. for 2 hours while passing nitrogen under pressure under it and approximately 450 g of niobium powder is obtained. The nitrogen content is 0.22%.

The physical properties of the obtained niobium powder, such as bulk density, average particle size, angle of repose, specific BET surface and maximum pore diameter, are shown in table 1.

The niobium powder thus obtained (approximately 0.1 g) is placed in the hopper of a tantalum-made device of an automatic forming unit (TAP-2R, Seiken) and is automatically pressed with a niobium wire with a diameter of 0.3 mm, thereby obtaining a molded product having the size is approximately 0.3 cm × 0.18 cm × 0.45 cm. The appearance and dispersion of the mass of the molded product are shown in table 1.

The obtained molded product was kept in a vacuum of 4 × 10 ^-3 Pa at 1250 ° C for 30 minutes in order to obtain a sintered material. 100 units of such sintered material are made, and each of them is subjected to electrochemical molding in an aqueous 0.1% phosphoric acid solution at a voltage of 20 V for 200 minutes, thereby obtaining a dielectric oxide film on the surface.

After that, the operation of immersing the sintered material in an aqueous 60% solution of manganese nitrate is repeated, followed by heating the material at 220 ° C for 30 minutes in order to form a layer of manganese dioxide, which serves as a counter electrode on the dielectric oxide film. A carbon layer and a silver paste layer are applied to this counter electrode layer in this order. After mounting a lead case on the device, the device is pressed as a whole with epoxy resin to manufacture a chip type capacitor. The capacitance factor of the capacitor, the average capacitance and the average leakage current (hereinafter abbreviated as “LC”) of the chip type capacitor (n = 100 units) are shown in Table 1. The LC value is a value measured at room temperature with a voltage of 6 , 3 V for 1 minute.

Example 2

A 1000 g niobium ingot is charged into a reactor made of US 304 material and hydrogen is continuously fed at 400 ° C. for 10 hours. After cooling, a large piece of hydrogenated niobium is placed in a container made of SUS 304 and containing zirconium balls and ground for 10 hours. After that, the resulting hydride is turned into a suspension of a concentration of 20 vol.%, Adding water, the suspension is loaded together with zirconium balls into a crusher and subjected to wet grinding at a temperature of 40 ° C or lower for 7 hours, thereby obtaining a ground suspension of niobium hydride. The obtained starting material, niobium powder, has an average particle size of 0.9 μm.

The resulting suspension (suspension concentration 98%) is placed in a container made of SUS 304 material and 200 g of barium oxide with an average particle size of 1 μm are added. In addition, zirconia beads are added and the contents are mixed for 1 hour using a shaking mixer. After removal of the zirconium beads, the mixture is placed in a cuvette made of niobium and dried in vacuum at a pressure of 1 × 10 ² Pa and 50 ° C.

After that, the resulting mixture was heated at 1 × 10 ^-2 Pa and 400 ° C for 4 hours in order to dehydrogenate niobium hydride, and then sintered under reduced pressure of 4 × 10 ^-3 Pa and 1100 ° C for 2 hours. The resulting sintered mass based on a mixture of niobium and barium oxide is cooled until the product temperature drops to 30 ° C or lower, and then crushed using a roller mill and obtaining a crushed powder of a mixture of niobium with barium oxide with an average particle size of 95 microns.

In a container of polytetrafluoroethylene placed 500 g of the obtained crushed powder of a mixture of niobium with barium oxide and 1000 g of purified by ion exchange water and cooled to 15 ° C or lower. Separately, a solution is prepared by mixing 600 g of 60% nitric acid, 150 g of 30% hydrogen peroxide and 750 g of purified water by ion exchange, and cooled to 15 ° C or lower. Then, 500 g of such an aqueous solution is added dropwise with stirring to an aqueous solution in which a crushed powder of a mixture of niobium with barium oxide is suspended, not allowing the temperature of the water to rise above 20 ° C. After completion of the dropwise addition, the solution was continuously stirred for an additional 1 hour, left to stand for 30 minutes, and then decanted. 2000 g of ion-exchanged water was added to the product, and the resulting solution was stirred for 30 minutes, left to stand for 30 minutes and then decanted. This operation is repeated 5 times. After that, the crushed niobium powder is placed in a column made of Teflon and washed with water for 4 hours using purified water by ion exchange. At this point, the conductivity of the wash water is 0.9 μS / cm.

After washing with water is completed, the crushed niobium powder is dried at 50 ° C under reduced pressure and subjected to nitriding treatment at 300 ° C for 3 hours, passing nitrogen under pressure under it, resulting in approximately 350 g of niobium powder. The nitrogen content is 0.28%.

The physical properties of the obtained niobium powder, such as bulk density, average particle size, angle of repose, specific BET surface and average pore diameter, are shown in table 1.

The niobium powder thus obtained (approximately 0.1 g) is placed in a hopper made of tantalum from an automatic forming apparatus (TAP-2R, Seiken) and is automatically pressed with a 0.3 mm diameter niobium wire to obtain a molded article having the size is approximately 0.3 cm × 0.18 cm × 0.45 cm. The appearance and dispersion of the mass of the molded product are shown in table 1.

The obtained molded product was kept under reduced pressure of 4 × 10 ⁻³ Pa at 1250 ° C. for 30 minutes in order to obtain sintered material. 100 units of such sintered material are made, and each of them is subjected to electrochemical treatment in an aqueous 0.1% solution of phosphoric acid at a voltage of 20 V for 200 minutes, thereby forming a dielectric oxide film on the surface.

After that, the operation of contacting the dielectric oxide film and an equivalent mixture of an aqueous 10% solution of ammonium persulfate and an aqueous 0.5% solution of anthraquinonesulfonic acid, followed by treatment with pyrrole vapor, is repeated at least 5 times in order to form a counter electrode including polypyrrole, on a dielectric oxide film.

A carbon layer and a silver paste layer are applied to this layer in this order. After mounting a lead casing on it, the device as a whole is pressed with epoxy resin to make a chip type capacitor. The capacitance factor of the capacitor, the average capacitance and the average LC value of the chip type capacitor (n = 100 units) are shown in Table 1. The LC value is a value measured at room temperature with a voltage of 6.3 V for 1 minute.

Examples 3 to 10

Niobium powders, molded products obtained from them, sintered materials and capacitors are obtained in the same manner as in example 1, except for changing the average particle size and the amount of added butyl polymethylmethacrylate, or in the same way as in example 2, except for changing average particle size and amount of barium oxide added. The physical properties of niobium powder and the appearance and dispersion of the mass of the molded product, as well as the capacitance and LC capacitor are shown in table 1.

Examples 11 to 22

The niobium powders, molded products and sintered materials according to examples 11 to 14 and 16 to 18 are obtained in the same manner as in example 1, and the niobium powders, molded products and sintered materials according to examples 15 and 19 to 22 are obtained in the same way. Thus, as in Example 2, each change regarding the use of an activator, the replacement of butyl polymethyl methacrylate and the replacement of barium oxide is shown in Table 1. The physical properties of the niobium powder, the appearance and mass dispersion of the molded product are shown in Table 1.

These molded products are kept under reduced pressure of 4 × 10 ^-3 Pa at 1250 ° C for 30 minutes in order to obtain sintered material. 100 units of each such sintered material are made, after which the products are subjected to electrochemical treatment using an aqueous 0.1% solution of phosphoric acid at a voltage of 20 V for 200 minutes, thereby forming a dielectric oxide film on the surface.

After that, each unit of sintered material on which a dielectric film was formed was immersed in an aqueous solution containing 25 wt.% Ammonium persulfate (solution 1), removed, dried at 80 ° С for 30 minutes, immersed in an isopropanol solution containing 18 wt. .% 3,4-ethylenedioxythiophene (solution 2), incubated in air at 60 ° C for 10 minutes, thereby carrying out oxidative polymerization. The resulting sintered material is again immersed in solution 1 and treated in the same manner as described above. This operation, from immersion in solution 1 to oxidative polymerization, is repeated 8 times. Then, the sintered material is washed with warm water at 50 ° C for 10 minutes and dried at 100 ° C for 30 minutes, whereby a counter electrode is formed, including electrically conductive poly (3,4-ethylenedioxythiophene).

A carbon layer and a silver paste layer are applied to this counter electrode in this order. After mounting a lead case on the device, the device is pressed as a whole with epoxy resin to manufacture a chip type capacitor. The capacitance factor for the capacitance of such a capacitor, the average capacitance and the average LC value of the chip type capacitor (n = 100 units) are shown in Table 1. The LC value is a value measured at room temperature with a voltage of 6.3 V for 1 minute.

Examples 23 to 25

Niobium powders, sintered materials and capacitors are obtained in the same manner as in example 2, except for the use of niobium-tin alloy powder as a starting material in example 23, niobium-rhenium hydride alloy powder in example 24, and powder in example 25 niobium-yttrium-boron hydride alloy. Physical properties, capacitance and LC capacitor are shown in table 1.

Comparative Examples 1 to 3

2000 g of potassium fluorniobate, carefully dried at 80 ° C, and sodium in a 10-fold molar excess relative to potassium fluorobiobate are charged into a crucible made of nickel and kept for 20 hours at 1000 ° C in argon atmosphere in order to conduct recovery reaction. After completion of the reaction, the reduction product is cooled, washed successively with water, 95% sulfuric acid and then water, dried in a vacuum and crushed in a ball mill with an aluminum container containing aluminosilicate balls, varying the grinding time. Each of the powdered products is immersed in a solution of the mixture in a ratio of 3: 2 (by weight) of 50% nitric acid and 10% aqueous hydrogen peroxide solution and mixed in this solution. After that, each powdered product is thoroughly washed with water until the water pH reaches 7 in order to remove impurities, and then dried in vacuum. The resulting niobium powder has an average particle size of from 1.3 to 10 microns.

After that, 50 g of the obtained niobium powder was loaded into a reactor made of SUS-304 material, and nitrogen was continuously passed through it at 300 ° C for 2 to 4 hours, thereby obtaining niobium nitride.

The physical properties of each of the niobium powders, such as bulk density, average particle size, angle of repose, specific BET surface and average pore diameter, are shown in table 1.

The niobium powder thus obtained (approximately 0.1 g) is placed in the hopper of a tantalum device made by an automatic forming unit (TAP-2R, Seiken) and is automatically pressed with a 0.3 mm diameter niobium wire. The results are shown in table 1.

Comparative Examples 4-9

Niobium powders having a bulk density of from 0.2 to 0.4 g / ml or from 2.6 to 3.3 g / ml, obtained in the same manner as in Example 2, except for changing the amount of added barium oxide having an average size particles of 1 micron. The physical properties of niobium powders are shown in table 1.

Each of the niobium powders thus obtained (approximately 0.1 g) is placed in the hopper of a tantalum-made device of an automatic forming unit (TAP-2R, Seiken) and is automatically pressed together with a niobium wire with a diameter of 0.3 mm, thereby forming products having a size of approximately 0.3 cm × 0.18 cm × 0.45 cm. The appearance and dispersion of the mass of these molded products are shown in table 1.

The obtained molded product was kept in a vacuum of 4 × 10 ^-3 Pa at 1250 ° C for 30 minutes in order to obtain a sintered material. 100 units of each of these sintered materials are made and subjected to electrochemical treatment using an aqueous 0.1% solution of phosphoric acid at a voltage of 20 V for 200 minutes, thereby forming a dielectric oxide film on the surface.

After this, the operations of bringing into contact of the dielectric oxide film and an equivalent mixture of an aqueous 10% aqueous solution of ammonium persulfate and an aqueous 0.5% solution of anthraquinonesulfonic acid are repeated at least 5 times, followed by treatment in pyrrole vapor, thereby forming a counter electrode including polypyrrole, on a dielectric oxide film.

A carbon layer and a silver paste layer are applied to this layer in this order. After mounting a lead casing on it, the device as a whole is pressed with epoxy resin to make a chip type capacitor. The capacitance factor of the capacitor, the average capacitance and the average LC value of the chip type capacitor (n = 100 units) are shown in Table 1. The LC value is a value measured at room temperature with a voltage of 6.3 V for 1 minute.

Examples 26-31

The hydrogenated niobium ingot is pulverized and dehydrated to obtain primary particles having an average particle size of 0.8 μm. The resulting primary particles are sintered and pulverized to obtain a granular niobium powder. Then 0.1 g of this granular powder was placed in a metal mold (4.0 mm × 3.5 mm × 1.8 mm) together with a separately prepared niobium wire having a length of 10 mm and a thickness of 0.3 mm, and applied load, as shown in table 2, using a device made from tantalum automatic molding machine (TAP-2R, firm Seiken), while receiving molded products. Each of the molded products is then sintered at 1300 ° C for 30 minutes to obtain the necessary sintered material. By controlling the amount of load applied in the forming device, sintered materials are obtained having a pore diameter distribution shown in Table 2. The volume, specific surface and CV value of the sintered material according to Example 26 is 24.7 mm ³ , 1.1 m ² / g and 85,000 μFV / g, respectively. For other examples, each of the values is within ± 2% of the value given in example 26.

Examples 32-34

Sintered materials are obtained in the same manner as in examples 26-28, with the exception that the average primary particle size is changed to 0.5 μm, sorting the primary particles. The volume, specific surface area and CV value of the sintered material according to Example 32 are 24.9 mm ³ , 1.5 m ² / g and 125,000 μFV / g, respectively. For other examples, each of the values is within ± 1% of the value given in Example 32. The pore diameter distribution for each of the sintered materials made is shown in Table 2.

Example 35

Sintered material is obtained in the same manner as in example 31, with the exception that instead of granular powder using niobium powder obtained in accordance with example 4. The volume, specific surface area and CV value of the sintered material according to example 35 is 24.8 mm ³ , 1.2 m ² / g and 78000 μFV / g, respectively. The pore diameter distribution of the sintered material is shown in table 2.

Comparative Examples 10 to 12

Sintered materials are obtained in the same manner as in examples 26-28, with the exception that instead of the granular niobium powder used in examples 26-28, niobium powder is used, obtained by heating at 1100 ° C the product of reduction of niobium chloride under the action of magnesium . The volume, specific surface area and CV value of the sintered material according to comparative example 10 is 24.3 mm ³ , 0.8 m ² / g and 84000 μFV / g, respectively. For other examples, each of the values is within ± 2% of the value given in comparative example 10. The pore diameter distribution of each of the obtained sintered materials is shown in table 2.

Example 36

60 units of each of the corresponding sintered materials obtained in the same manner as in example 21 and in each of examples 26-35 are subjected to electrochemical treatment in an aqueous 0.1% solution of phosphoric acid at 80 ° C and a voltage of 20 V for 1000 minutes, while forming a dielectric oxide film on the surface. The obtained sintered materials after electrochemical processing are divided into groups, each of which consists of 30 units. 30 units of sintered material in each group are impregnated with two types of cathodic agents A and B, as shown in table 3. Then, in this order, a carbon layer and a layer of silver paste are applied and the device is pressed with epoxy resin, making a chip type capacitor. The implementation coefficient of the capacitor capacitance and the moisture resistance value for each capacitor are shown in table 4.

Reference Example 13

60 units of each of the corresponding sintered materials obtained in the same manner as in each of comparative examples 9 to 12 are subjected to electrochemical treatment in an aqueous 0.1% solution of phosphoric acid at 80 ° C and a voltage of 20 V for 1000 minutes, forming a dielectric oxide film on the surface of the sintered material. The obtained sintered materials after electrochemical processing are divided into groups, each of which consists of 30 units. 30 units of sintered material in each group are impregnated with cathode agent A, as shown in Table 3. Then, in this order, a carbon layer and a layer of silver paste are applied, and the device is pressed with epoxy resin to produce a chip type capacitor. The implementation coefficient of the capacitor capacitance and the moisture resistance value for each capacitor are shown in table 4.

Example 37

In the same manner as in Example 2, a suspension was obtained by grinding the starting niobium hydride powder. The niobium hydride powder has an average particle size of 0.6 μm. After sedimentation of the suspension in a centrifuge, the supernatant is removed by decantation. Anhydrous acetone was added to the resulting product so as to obtain a 40% by weight suspension, and was thoroughly suspended. After sedimentation in a centrifuge of the obtained liquid product, the supernatant is removed by decantation. This operation is repeated three times. Then anhydrous acetone is added to the resulting product so as to obtain a 60% by weight suspension, and carefully suspended. The resulting suspension is placed in a container made of SUS, and barium oxide with an average particle diameter of 1.4 μm and 23 μm in the amount of 15 wt.% And 10 wt.% By weight of niobium, respectively, is added thereto. In addition, zirconia beads are added and the contents are stirred for 1 hour using a shaking mixer. After removing the zirconium beads, the mixture is placed in a niobium cuvette and dried in vacuum at 1 × 10 ² Pa and 50 ° C.

A sintered mass based on a mixture of niobium and barium oxide is obtained in the same manner as in example 2.

500 g of the obtained crushed powder of a mixture of niobium with barium oxide and 1000 g of purified water by ion exchange are cooled to 15 ° C or less with stirring, ensuring that the water temperature does not rise above 20 ° C. After the addition is complete, the suspension is continuously stirred for an additional 1 hour, left to stand for 30 minutes and then decanted. Then 2000 g of purified by ion exchange water are added and the resulting suspension is stirred for 30 minutes, left to stand for 30 minutes and then decanted. This operation is repeated 5 times. After that, the crushed niobium powder is placed in a column made of Teflon and washed with water for 4 hours using purified water by ion exchange. At this point, the conductivity of the wash water is 0.5 μS / cm.

After the washing is completed, the crushed niobium powder is dried at 50 ° C under reduced pressure and subjected to nitriding at 3000 ° C for 3 hours, passing nitrogen through it under pressure, resulting in 350 g of niobium powder. The nitrogen content is 0.30%.

Examples 38 to 44

Crushed niobium powder mixed with an activator is obtained in the same manner as in Example 37, varying the type of activator added, the average pore diameter and the amount of two types of niobium powder used for mixing. The solvent used to dissolve the activator is selected from water, acid, alkali, a solvent containing an ion exchange resin, a solvent of ammonium nitrate and a solution containing ethylene diamine tetraacetate. The activator is dissolved in the same manner as in example 37, while obtaining a niobium powder. The physical properties of the obtained niobium powder are shown in table 5.

The molded product and sintered material are made in the same manner as in example 37, for the subsequent manufacture of a chip type capacitor. The appearance and dispersion of the mass of the molded product and the capacitor, as well as the average value of the LC capacitor are shown in table 5.

Examples 45 to 47

The niobium alloy powder was obtained in the same manner as in Example 37, using niobium-neodymium alloy powder as the starting material in Example 45, niobium-tungsten alloy powder in Example 46, and niobium-tantalum alloy powder in Example 47, respectively. The physical properties of the obtained niobium alloy powder are shown in table 5.

The molded product and sintered material are made in the same manner as in example 37, for the subsequent manufacture of a chip type capacitor. The appearance and dispersion of the mass of the molded product and the capacitor, as well as the average value of the LC capacitors are shown in table 5.

Examples 48 to 58

Sintered niobium material is obtained in the same manner as in example 2 using the niobium powder obtained according to examples 37-47. The distribution of sintered niobium pore diameter is shown in table 6.

Examples 59 to 69.

Prepare 100 units of each of the sintered materials obtained in examples 48 to 58 and undergo electrochemical treatment in an aqueous 0.1% solution of phosphoric acid at 80 ° C and a voltage of 20 V for 1000 minutes, thereby forming a dielectric film oxide on the surface of the sintered material. The obtained sintered materials are impregnated with cathodic agents shown in Table 3. Then, in this order, a carbon layer and a layer of silver paste are applied, and the device as a whole is pressed with epoxy resin, making a chip type capacitor. The coefficient of realization of the capacitance of the capacitor and the EPS of the manufactured capacitors are shown in table 7.

Comparative Examples 14 to 17

100 units of each of the sintered materials obtained in the same manner as in comparative examples 9 to 12 are subjected to electrochemical treatment using an aqueous 0.1 wt.% Solution of phosphoric acid at 80 ° C and a voltage of 20 V for 1000 minutes while forming a dielectric oxide film on the surface. The obtained sintered materials are impregnated with cathodic agents shown in Table 3. Then, in this order, a carbon layer and a layer of silver paste are applied and the whole device is pressed with epoxy resin, making a chip type capacitor. The coefficient of realization of the capacitance of the capacitor and the EPS of the manufactured capacitors are shown in table 7.

Table 1 Activator Physical properties of niobium powder Type of Quantity added
(wt.%) Average particle size
(microns) Bulk density
(g / ml) Average particle size
(microns) Slope Angle (°) Specific BET surface (m ² / g) Maximum pore diameter
(microns) Example 1 Butyl polymethyl methacrylate 10 1,0 0.7 120 42 1.4 1,2 Example 2 Wow 17 1,0 1,1 95 45 1,6 1,1 Example 3 Butyl polymethyl methacrylate 5 1,0 1,2 120 40 1.4 1,0 Example 4 Butyl polymethyl methacrylate one 1,0 1.9 120 37 1,2 0.8 Example 5 Wow 35 1,0 0.5 95 53 1.8 0.9 Example 6 Wow 25 1,0 0.8 95 48 1.7 1,0 Example 7 Wow 17 3.0 1,1 95 45 1,6 2,8 Example 8 Wow 17 5,0 1,2 95 45 1.4 5.3 Example 9 Wow 17 9.0 1,5 95 40 1,2 7.5 Example 10 Wow 17 21 1.7 95 35 0.9 22 Example 11 camphor 40 one hundred 1.9 180 32 1.3 78 Example 12 butyl polyacrylate 8 10 1.7 250 thirty 1.4 7.5 Example 13 polyvinyl alcohol 3 3.0 1,2 80 49 1.4 3.2 Example 14 Zno fifteen 3.0 1,1 85 44 1.7 2,4 Example 15 Re ₂ O ₇ 10 4.0 1,0 110 42 1.8 3,1 Example 16 Wo ₂ 7 3.0 1.3 one hundred 45 1,6 3,1 Example 17 Sno ₂ 10 0.8 1,2 85 48 1,6 0.8 Example 18 MgO twenty 3.0 1,1 90 45 1.8 2.6 Example 19 Mn (NO ₃ ) ₂ 10 2.0 1,5 one hundred 43 1,5 2,3 Example 20 CaCO ₃ 10 1,0 1,0 85 42 1.7 0.8 5 5,0 5.8 Example 21 CaCO ₃ 9 0.5 1,1 88 44 1.7 0.6 B ₂ O ₃ 9 1,0 1.4 Example 22 Y ₂ O ₃ 3 0.7 1,1 90 46 1,6 0.9 B ₂ O ₃ fifteen 1,0 1.4 Example 23 Wow 17 1,0 1,0 95 46 1.4 1,2 Example 24 Wow 17 1,0 1,1 90 45 1,5 0.9 Example 25 Mn (NO ₃ ) ₂ 17 1,0 1,1 85 49 1.3 1.3 Comparative Example 1 - 0 - 2.6 1.3 75 3,1 0.7 Reference Example 2 - 0 - 2.9 2.6 72 1,5 1.9 Reference Example 3 - 0 - 3.0 10 69 0.49 9.0 Reference Example 4 Wow 41 1,0 0.4 95 49 1.8 0.8 Reference Example 5 Wow 45 1,0 0.3 90 56 1.9 0.8 Reference Example 6 Wow fifty 1,0 0.2 65 59 2.2 0.9 Reference Example 7 Wow 0.8 1,0 2.6 85 48 1,2 0.7 Reference Example 8 Wow 0.6 1,0 3.0 90 48 1,0 0.6 Reference Example 9 Wow 0.4 1,0 3.3 one hundred 44 0.9 0.6

Table 1 (continued) Sintered material Capacity sales ratio (%) Electrical specifications Defects in appearance: delamination, cracking, distortion The dispersion of the mass (g / sintered material) Capacitance (μF) Leakage Current LC (μA) Example 1 are absent 0.1 ± 0.002 92 409 13 Example 2 are absent 0.1 ± 0.002 91 460 19 Example 3 are absent 0.1 ± 0.002 92 409 17 Example 4 are absent 0.1 ± 0.002 89 387 fifteen Example 5 are absent 0.1 ± 0.002 90 472 21 Example 6 are absent 0.1 ± 0.002 92 460 22 Example 7 are absent 0.1 ± 0.002 88 563 26 Example 8 are absent 0.1 ± 0.002 91 523 eighteen Example 9 are absent 0.1 ± 0.002 93 419 13 Example 10 are absent 0.1 ± 0.002 91 263 5 Example 11 are absent 0.1 ± 0.002 90 392 19 Example 12 are absent 0.1 ± 0.002 90 387 12 Example 13 are absent 0.1 ± 0.002 93 539 25 Example 14 are absent 0.1 ± 0.002 89 516 22 Example 15 are absent 0.1 ± 0.002 92 501 fourteen Example 16 are absent 0.1 ± 0.002 89 512 17 Example 17 are absent 0.1 ± 0.002 92 408 eleven Example 18 are absent 0.1 ± 0.002 95 608 23 Example 19 are absent 0.1 ± 0.002 91 382 17 Example 20 are absent 0.1 ± 0.002 94 588 29th Example 21 are absent 0.1 ± 0.002 97 590 23 Example 22 are absent 0.1 ± 0.002 90 446 21 Example 23 are absent 0.1 ± 0.002 91 450 13 Example 24 are absent 0.1 ± 0.002 93 558 fifteen Example 25 are absent 0.1 ± 0.002 91 446 13 Comparative Example 1 cannot be molded - - - Reference Example 2 cannot be molded - - - Reference Example 3 cannot be molded - - - Reference Example 4 are present 0.1 ± 0.015 91 396 eighteen Reference Example 5 are present 0.1 ± 0.026 92 409 eighteen Reference Example 6 are present 0.1 ± 0.046 95 432 17 Reference Example 7 are absent 0.1 ± 0.002 42 143 9 Reference Example 8 are absent 0.1 ± 0.002 37 115 7 Reference Example 9 are absent 0.1 ± 0.002 22 64 5

Table 4 A method of manufacturing a sintered material Method of impregnation with a cathode agent The coefficient of implementation of the capacity,% Moisture resistance value The number of units having a capacity of 100% to less than 110% The number of units having a capacity of 110% to less than 120% Example 21 BUT 97 30/30 0/30 Example 26 BUT 82 30/30 0/30 AT 88 30/30 0/30 Example 27 BUT 84 30/30 0/30 AT 87 30/30 0/30 Example 28 BUT 79 27/30 3/30 Example 29 BUT 83 30/30 0/30 Example 30 BUT 80 30/30 0/30 Example 31 BUT 81 30/30 0/30 Example 32 BUT 85 30/30 0/30 Example 33 BUT 81 30/30 0/30 Example 34 BUT 82 28/30 2/30 Example 35 BUT 95 30/30 0/30 Reference Example 9 BUT 22 4/30 26/30 Reference Example 10 BUT 71 15/30 15/30 Reference Example 11 BUT 73 17/30 13/30 Reference Example 12 BUT 68 19/30 11/30

Table 5 Activator Physical properties of niobium powder Type of Added amount (wt.%) The average particle size (microns) Bulk density (g / ml) The average particle size (microns) Slope Angle (°) Specific BET surface (m ² / g) Maximum pore diameter (μm) Wow fifteen 1.4 0.9 98 49 1.7 1,5 Example 37 10 23 25 Wow 17 2.0 1,0 130 47 1,6 2.2 Example 38 fifteen thirty 34 Example 39 CaCO ₃ twenty 3.0 1,2 202 44 1,5 3,1 10 fifteen eighteen MgO eighteen 1,5 1,0 121 45 1.7 1,6 Example 40 BrO ₃ 8 10 12 Al ₂ O ₃ twenty 2.0 0.9 140 49 1.7 2.1 Example 41 twenty 25 24 MgO fifteen 1,5 0.9 138 47 1.8 1.8 Example 42 Al ₁ O ₃ fifteen twenty 22 Example 43 Y ₂ O ₃ fifteen 2.0 1,1 98 47 1,6 1.9 Al ₂ O ₃ 10 25 24 MgO fifteen 1,5 0.9 135 46 1.9 1.9 Example 44 twenty 25 22 Wow fifteen 1.4 0.9 150 45 1.9 1.3 Example 45 10 23 22 Wow fifteen 1.4 0.9 111 49 1.7 1.7 Example 46 10 23 26 Wow fifteen 1.4 0.9 130 46 1.7 1.4 Example 47 10 23 21

Table 5 (continued) Sintered material Capacity sales ratio (%) Electrical specifications Defects in appearance: delamination, cracking, distortion The dispersion of the mass (g / sintered material) Capacitance (μF) Leakage Current LC (μA) Example 37 are absent 0.1 ± 0.002 98 592 23 Example 38 are absent 0.1 ± 0.002 97 587 23 Example 39 are absent 0.1 ± 0.002 93 557 22 Example 40 are absent 0.1 ± 0.002 93 556 twenty Example 41 are absent 0.1 ± 0.002 98 585 24 Example 42 are absent 0.1 ± 0.002 98 589 twenty Example 43 are absent 0.1 ± 0.002 97 581 22 Example 44 are absent 0.1 ± 0.002 98 590 twenty Example 45 are absent 0.1 ± 0.002 98 592 eighteen Example 46 are absent 0.1 ± 0.002 98 587 19 Example 47 are absent 0.1 ± 0.002 98 587 24

Industrial applicability

The niobium powder according to the present invention, having a bulk density of from 0.5 to 2.5 g / ml, an average particle size of from 10 to 1000 μm, an angle of repose of 10 to 60 ° and a specific BET surface of 0.5 to 40 m ² / g, has good fluidity and is suitable for continuous molding. By using sintered niobium material for the manufacture of a capacitor electrode, which is obtained by sintering niobium powder and which is characterized by a pore size distribution in which there is a maximum pore diameter in the range from 0.01 μm to 500 μm and preferably there are many peaks, a high coefficient can be achieved capacitor capacitance and a capacitor is manufactured, characterized by low leakage current and high moisture resistance.

Claims (65)

1. Niobium powder for the manufacture of a capacitor containing at least one element selected from the group consisting of nitrogen, carbon, boron and sulfur, having a bulk density of from 0.5 to 2.5 g / ml 2. The niobium powder according to claim 1, the average particle size of which is from 10 to 1000 microns. 3. The niobium powder according to claim 1 or 2, the angle of repose of which is from 10 to 60 °. 4. Niobium powder according to any one of claims 1 to 3, the specific surface of which, determined by the adsorption isotherms by the Brunauer-Emmett-Teller method (BET surface), is from 05 to 40 m ² / g. 5. Niobium powder according to any one of claims 1 to 4, in which the pore diameter distribution has a maximum pore diameter in the range from 0.01 to 500 microns. 6. The niobium powder according to claim 5, wherein the pore diameter distribution has a plurality of pore diameter maxima. 7. The niobium powder according to claim 5 or 6, in which one of the maxima of the distribution of pore diameter is in the range from 0.5 to 100 microns. 8. Niobium powder according to any one of claims 1 to 7, in which at least one element is contained in an amount of 200,000 parts by weight per million or less. 9. Sintered niobium material for a capacitor obtained using niobium powder according to any one of claims 1 to 8. 10. The sintered material according to claim 9, characterized by a distribution of pore diameter having a maximum pore diameter in the range from 0.01 to 500 microns. 11. Sintered niobium material for the manufacture of a capacitor electrode, characterized by a distribution of pore diameter, in which there are many maxima of pore diameter. 12. The sintered niobium material according to claim 11, characterized by a distribution of pore diameter, in which there are two maximum pore diameter. 13. The sintered niobium material according to claim 11 or 12, characterized by a plurality of maxima of pore diameter containing two maxima with the highest intensity, which are in the range from 0.2 to 0.7 μm and in the range from 0.7 to 3 μm, respectively . 14. The sintered niobium material according to any one of claims 11 to 13, characterized by a plurality of pore diameter maxima containing the maximum with the highest relative intensity, which is in the region of larger diameters than the maximum having the next relative intensity. 15. Sintered niobium material according to any one of claims 9 to 14, characterized by a volume of sintered material equal to 10 mm ³ or more, including the volume of empty pores. 16. The sintered niobium material according to any one of claims 9 to 15, having a specific surface area of from 0.2 to 7 m ² / g. 17. Sintered niobium material according to any one of paragraphs.9-16, part of which is subjected to nitriding. 18. The sintered niobium material according to any one of claims 12-17, obtained from a molded niobium billet and as a result having a specific charge CV equal to from 40,000 to 200,000 μFV / g after sintering at a temperature of 1300 ° C. 19. A capacitor comprising one electrode made using sintered niobium material according to any one of claims 9-18, a counter electrode and a dielectric material located between them. 20. The capacitor according to claim 19, in which the dielectric material mainly includes niobium oxide. 21. The capacitor according to claim 19, wherein the counter electrode is at least one material selected from the group consisting of an electrolyte solution, an organic semiconductor, and an inorganic semiconductor. 22. The capacitor according to item 21, in which the counter electrode is an organic semiconductor, and the organic semiconductor is at least one material selected from the group consisting of an organic semiconductor comprising a tetramer of benzopyrroline and chloranil, an organic semiconductor mainly comprising tetratiotetracene, organic a semiconductor, mainly including tetracyanoquinodimethane, and an electrically conductive polymer. 23. The capacitor according to item 22, in which the electrically conductive polymer is at least one polymer selected from the group consisting of polypyrrole, polythiophene, polyanaline and their substituted derivatives. 24. The capacitor according to item 22, in which the electrically conductive polymer is an electrically conductive polymer obtained by introducing a dopant into a polymer containing a repeating unit represented by the following formulas (1) and (2)

where the radicals from R ¹ to R ⁴ each independently represent a monovalent group selected from the group consisting of hydrogen, a linear or branched, saturated or unsaturated alkyl, alkoxy or alkyl substituted ester group containing from 1 to 10 carbon atoms, a halogen atom, a nitro group, a cyano group, a primary, secondary or tertiary amino group, a CF ₃ group, phenyl or substituted phenyl; each of the pairs R ¹ and R ² , R ³ and R ⁴ can be combined arbitrarily with the formation of a bivalent chain to obtain at least one 3-, 4-, 5-, 6- or 7-membered saturated or unsaturated cyclic hydrocarbon structure together with carbon atoms substituted with R ⁴ and R ² or radicals R ³ and R ⁴ ; the combined cyclic chain may contain a bond with a carbonyl, ether group, ester group, amide group, sulfide group, sulfinyl, sulfonyl or imino group in an arbitrary position; X represents an oxygen atom, a sulfur atom or a nitrogen atom; R ^{5 is} present only when X represents a nitrogen atom and independently represents a hydrogen atom or a linear or branched, saturated or unsaturated alkyl group containing from 1 to 10 carbon atoms. 25. The capacitor according to paragraph 24, wherein the electrically conductive polymer is an electrically conductive polymer containing a repeating unit represented by the following formula (3):

where R ⁶ and R ⁷ each independently represents a hydrogen atom, a linear or branched, saturated or unsaturated alkyl group containing from 1 to 6 carbon atoms, or a substituent capable of forming at least one 5-, 6- or 7-membered saturated cyclic a hydrocarbon structure containing two oxygen moieties derived from alkyl groups that combine with each other in an arbitrary position; and the cyclic structure includes a structure containing a vinylene bond, which may be substituted, and a phenylene structure, which may be substituted. 26. The capacitor according to item 22, in which the electrically conductive polymer is an electrically conductive polymer obtained by introducing a dopant into poly (3,4-ethylenedioxythiophene). 27. The capacitor according to claim 19, in which the counter electrode is made of a material at least partially having a layered structure. 28. The capacitor according to claim 19, in which the material of the counter electrode contains as an dopant an organic anion - sulfonate. 29. A method of producing a niobium powder according to any one of claims 1 to 8, including activation processing of the original niobium powder or niobium material. 30. The method of producing niobium powder according to clause 29, according to which the activation processing of the original niobium powder or niobium material is carried out in at least one stage selected from the sintering stage and the crushing stage. 31. The method of producing niobium powder according to clause 29 or 30, according to which the activation processing of the initial niobium powder or niobium material is carried out using a mixture of the original niobium powder or niobium material and activator. 32. The method for producing the niobium powder according to any one of claims 29-31, wherein the average particle size of the starting niobium powder or niobium material subjected to activation processing is 0.01-10 microns. 33. The method of producing niobium powder according to any one of paragraphs.29-32, characterized in that the initial niobium powder or niobium material contains at least one element selected from the group consisting of nitrogen, carbon, boron and sulfur, in an amount of 200,000 wt. .h. per million or less. 34. A method of producing a niobium powder according to any one of claims 29 to 33, wherein the niobium material is at least one material selected from the group consisting of niobium hydride, niobium alloy or niobium hydride alloy. 35. The method for producing the niobium powder according to claim 34, a component other than niobium contained in the niobium alloy or in the niobium hydride alloy is at least one element selected from the group consisting of elements having atomic numbers from 88 or below, with the exception of hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, iodine, niobium, helium, neon, argon, krypton, xenon and radon. 36. A method for producing a niobium powder according to claim 31, wherein the mixture containing the starting niobium powder or niobium material and an activator is obtained by mixing from a solvent. 37. The method of producing the niobium powder according to clause 36, wherein the solvent is at least one solvent selected from the group consisting of water, alcohols, ethers, cellosolves, ketones, aliphatic hydrocarbons, aromatic hydrocarbons and halogenated hydrocarbons. 38. The method of producing niobium powder according to p, according to which the activator is used in an amount of from 1 to 40 wt.%, Calculated on the total amount of the original powder of niobium or niobium compounds. 39. The method of producing niobium powder according to p. 31 or 38, according to which the average particle size of the activator is from 0.01 to 500 microns. 40. The method of producing niobium powder according to any one of paragraphs.31, 38, or 39, according to which the activator is characterized by the presence of several peaks of the distribution of particle sizes. 41. The method of producing niobium powder according to any one of paragraphs.31 or 38-40, according to which the activator is a compound that is removed as a gas at 2000 ° C or less. 42. The method for producing the niobium powder according to paragraph 41, wherein the activator is at least one compound selected from the group consisting of naphthalene, anthracene, quinone, camphor, polyacrylic acid, an acrylic acid ester polymer, polyacrylamide, polymethacrylic acid, a methacrylic acid ester polymer, polymethacrylamide, polyvinyl alcohol, NH ₄ Cl, ZnO, WO ₂ , SnO ₂ and MnO ₃ . 43. The method of producing niobium powder according to any one of paragraphs.31 or 38-40, according to which the activator is at least one compound selected from the group consisting of a water-soluble compound, a compound soluble in organic solvents, a compound soluble in acid solutions , a compound soluble in alkali solutions, a compound forming a complex providing the solubility of the compound in water, an organic solvent, an acid solution or an alkaline solution, and a compound that becomes dissolved vorimym in water, organic solvent, acidic solution or alkaline solution at 2,000 ° C or less. 44. The method for producing the niobium powder according to claim 43, wherein the activator is at least one compound selected from the group consisting of metal compounds with carboxylic acid, sulfuric acid, sulfurous acid, halogen, perhalogen acid, hypohalogen acid, nitric acid , nitrous acid, phosphoric acid, acetic acid, oxalic acid or boric acid, metals, metal hydroxides and metal oxides. 45. The method of producing niobium powder according to item 43, according to which the activator is at least one substance selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, France, beryllium, magnesium, calcium, strontium, barium, radium, scandium, yttrium, cerium, neodymium, titanium, zirconium, hafnium, vanadium, niobium, tantalum, molybdenum, tungsten, manganese, rhenium, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, silver, gold, zinc, cadmium, boron, aluminum, gallium, indium, thallium, silicon, germanium, tin, lead, arsenic , Antimony, bismuth, selenium, tellurium, polonium and compounds thereof. 46. The method for producing the niobium powder according to claim 31, wherein the activation treatment is a treatment in which the activator is removed by heating and / or under reduced pressure before or during the sintering step. 47. The method for producing the niobium powder according to claim 31, wherein the activation treatment is a treatment in which the activator component is removed by contacting the solvent with a sintered or crushed product after the sintering step and during or after the crushing step. 48. The method for producing the niobium powder according to clause 47, wherein the solvent is at least one substance selected from the group consisting of water, an organic solvent, an acid solution or an alkaline solution, and a solution containing a ligand to form a soluble complex. 49. The method for producing the niobium powder according to claim 48, wherein the acid solution is a solution of at least one compound selected from the group consisting of nitric acid, sulfuric acid, hydrofluoric acid and hydrochloric acid. 50. The method for producing the niobium powder according to claim 48, wherein the alkaline solution contains at least one compound selected from the group consisting of alkali metal hydroxide and ammonia. 51. The method for producing the niobium powder according to claim 48, wherein the ligand is at least one compound selected from the group consisting of ammonia, glycine and ethylenediaminetetraacetic acid. 52. The method for producing the niobium powder according to claim 48, wherein the organic solvent is methyl isobutyl ketone. 53. A method of producing a nitrogen-containing niobium powder, comprising treating the niobium powder according to any one of claims 1 to 7, using at least one method selected from the group consisting of liquid-phase nitriding, ion nitriding and gas-phase nitriding. 54. A method of producing a carbon-containing niobium powder, comprising treating the niobium powder according to any one of claims 1 to 7, using at least one method selected from the group consisting of solid phase carbonization and liquid phase carbonization. 55. A method of obtaining a boron-containing niobium powder, comprising processing a niobium powder according to any one of claims 1 to 7, using at least one method selected from the group consisting of gas-phase boronization and solid-phase boronation. 56. A method of producing a sulfur-containing niobium powder, comprising treating the niobium powder according to any one of claims 1 to 7, using at least one method selected from the group consisting of gas-phase sulfidation, ionic sulfidation and solid-phase sulfidation. 57. Niobium powder obtained by the method according to any one of paragraphs.29-56. 58. A method of obtaining a sintered niobium material, including obtaining niobium powder, pressing and sintering, the implementation of which use niobium powder according to any one of claims 1 to 8 and 57. 59. A method of manufacturing a capacitor comprising one electrode based on sintered niobium material, a dielectric material formed on the surface of the sintered material and a counter electrode that is located on the dielectric material, where the sintered niobium material is obtained by sintering a niobium powder according to any one of claims 1 to 8 and 57. 60. A method of manufacturing a capacitor according to § 59, according to which a dielectric material is formed by electrolytic oxidation. 61. A method of manufacturing a capacitor comprising one electrode based on sintered niobium material, a dielectric material formed on the surface of the sintered material and a counter electrode that is located on a dielectric material where sintered niobium material is used according to any one of claims 9-18. 62. An electronic circuit manufactured using a capacitor according to any one of claims 19-28. 63. An electronic device manufactured using a capacitor according to any one of claims 19-28. Priorities for items: 05/15/2001 according to claims 1-11, 19-63; November 6, 2001 according to claims 12-18.

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