WO2002004152A1 - Poudre metallique contenant de l'azote, son procede de preparation, condensateur electrolytique solide et agglomere poreux fabrique au moyen de cette poudre metallique - Google Patents

Poudre metallique contenant de l'azote, son procede de preparation, condensateur electrolytique solide et agglomere poreux fabrique au moyen de cette poudre metallique Download PDF

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Publication number
WO2002004152A1
WO2002004152A1 PCT/JP2001/005998 JP0105998W WO0204152A1 WO 2002004152 A1 WO2002004152 A1 WO 2002004152A1 JP 0105998 W JP0105998 W JP 0105998W WO 0204152 A1 WO0204152 A1 WO 0204152A1
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Prior art keywords
nitrogen
powder
niobium
tantalum
tantalum powder
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PCT/JP2001/005998
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English (en)
Japanese (ja)
Inventor
Isayuki Horio
Tomoo Izumi
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Cabot Supermetals K.K.
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Publication of WO2002004152A1 publication Critical patent/WO2002004152A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G4/00—Fixed capacitors; Processes of their manufacture
    • H01G4/002—Details
    • H01G4/005—Electrodes
    • H01G4/008—Selection of materials
    • H01G4/0085—Fried electrodes
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/04—Making non-ferrous alloys by powder metallurgy
    • C22C1/047—Making non-ferrous alloys by powder metallurgy comprising intermetallic compounds
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
    • C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
    • C23C8/24—Nitriding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F2999/00—Aspects linked to processes or compositions used in powder metallurgy

Definitions

  • the present invention relates to a nitrogen-containing tungsten powder or a nitrogen-containing niobium powder suitable for forming an anode electrode of a solid electrolytic capacitor and a method for producing the same.
  • the tantalum powder that is mainly used is obtained by subjecting evening powder obtained by sodium reduction of tantalum fluoride potassium salt to a vacuum heat treatment and then deoxidizing it. Tantalum powder capable of achieving a high CV value of about 100000 FVZ g has been obtained.
  • tantalum powder is press-molded, vacuum-sintered, and then anodized to form a dielectric layer. After that, a solid electrolyte is formed in the pores of the tantalum sintered body.
  • the uniformity of pore size and distribution is most affected by the sintering process in the capacitor manufacturing process. ⁇ -If the sintering proceeds too much, for example, because the sintering temperature is too high, it is not possible to secure enough pores to form a solid electrolyte, and the capacity of the capacitor will decrease. On the other hand, if the progress of sintering is insufficient due to factors such as the sintering temperature being too low, the stability of the dielectric film becomes insufficient, such as an increase in leakage current.
  • the tantalum powder becomes finer, the size and distribution of pores become more uniform.
  • the properties are more likely to depend on such sintering conditions, and slight changes in conditions such as the sintering temperature greatly change the state of vacancies, making it impossible to stably obtain tantalum powder having desired physical properties. There was a case.
  • U.S. Pat. No. 5,448,447 and U.S. Pat. No. 2,316,444 disclose that by adding nitrogen to tan powder, it is possible to reduce the amount to less than 300 FV / g. It discloses effects of dielectric film stability such as reduction of leakage current when CV powder is subjected to high-pressure formation at 100 V or more.
  • U.S. Pat. No. 1,875,988 discloses reducing thermal leakage by reducing the amount of oxygen by performing thermal nitriding at 450 below after deoxygenation.
  • a tungsten powder or a niobium powder that suppresses the sintering rate and facilitates appropriate control of the sintering process, and produces a porous sintered body with uniform pore size and distribution.
  • a high CV capacitor that suppresses the sintering rate and facilitates appropriate control of the sintering process.
  • the nitrogen-containing tantalum powder or the nitrogen-containing niobium powder of the present invention contains 500 to 300 ppm of nitrogen, and the variation of the nitrogen content among the particles is 100% or less.
  • the titanium powder or the niobium powder is heated while moving in a nitrogen-containing atmosphere to contain nitrogen in the tantalum powder or the niobium powder. And a nitrogen treatment step of causing
  • the porous sintered body of the present invention is characterized by sintering the above-mentioned nitrogen-containing tantalum powder or nitrogen-containing niobium powder.
  • a solid electrolytic capacitor according to the present invention includes an anode electrode made of the porous sintered body described above. BRIEF DESCRIPTION OF THE FIGURES
  • FIG. 1 is a graph showing the relationship between the nitrogen content of the nitrogen-containing tantalum powder produced in the example and the density ratio D s ZD g before and after sintering.
  • FIG. 2 is a graph showing the relationship between the nitrogen content and the breakdown voltage (B DV) of the nitrogen-containing tantalum powder produced in the example.
  • the nitrogen-containing tantalum powder or the nitrogen-containing niobium powder of the present invention contains 500 to 300 ppm of nitrogen.
  • nitrogen is contained in such a proportion, excessive progress of sintering is suppressed when sintering nitrogen-containing oxygen powder or nitrogen-containing niobium powder.
  • a porous sintered body having pores of a size suitable for forming a solid electrolyte uniformly can be obtained. This is because the surface diffusion of tantalum atoms, which occurs at the sintering neck of the primary particles, is inhibited by nitrogen atoms present in the surface layer of the primary particles. Conceivable.
  • the nitrogen content is less than 500 ppm, the effect of suppressing the sintering of tantalum powder or niobium powder by nitrogen is insufficient.
  • it exceeds 30,000 ppm the distribution of nitrogen in the tantalum powder or the niobium powder becomes uneven, and nitride crystals are generated, thereby reducing the capacity of the finally obtained capacitor.
  • the preferred nitrogen content of the nitrogen-containing tantalum powder or the nitrogen-containing niobium powder is 3000-15000 ppm.
  • the variation in the nitrogen content among the particles is 100% or less.
  • “variation in the nitrogen content among the particles” is a value determined as follows. First, a fixed amount of nitrogen-containing tantalum powder or nitrogen-containing niobium powder is used as a measurement sample, which is burned and the NOx gas generated is quantified to measure the mass of nitrogen contained in the sample. ) Determine the average nitrogen content (p pm) of the powder. The measurement sample is usually about 1 g.
  • the electron beam probe micro area measurement (EPMA) is used to determine the nitrogen content of each of the 10 randomly extracted particles in the area with a spot diameter of 30 m to determine the nitrogen content (p pm) of each particle. .
  • the difference ⁇ between the maximum nitrogen content (ppm) and the minimum nitrogen content (ppm) is calculated.
  • the value of the ratio of ⁇ to the percentage expressed as a percentage is defined as the variation (%) of the nitrogen content among the particles.
  • the variation of the nitrogen content among the particles exceeds 100%, the effect of suppressing the sintering of nitrogen is exhibited as the whole powder, but the sintering progresses unevenly. As a result, the size and distribution of the pores in the porous sintered body become non-uniform, making the capacitor unsuitable for use as an anode electrode of a capacitor. More preferably, the variation in the nitrogen content among the particles is 50% or less.
  • the particle size and surface area of the nitrogen-containing tantalum powder or nitrogen-containing niobium powder of the present invention are not particularly limited, but preferably have an average particle diameter of 0.7 to 3 m, and a surface area of 3000 to 30000 cm 2 by a BET method. / g. With such nitrogen-containing evening powder or nitrogen-containing niobium powder, more than 40,000 zFVZg High-capacity capacitors can be manufactured.
  • Such a nitrogen-containing tantalum powder or a nitrogen-containing niobium powder usually includes a reduction step of reducing a tantalum compound or a niobium compound as a raw material to obtain a tantalum powder or a niobium powder, and a heat treatment for thermally coagulating the tantalum powder or the niobium powder. It can be obtained by a production method having an agglomeration step, a deoxidation step of heating and deoxidizing a tantalum powder or a niobium powder in the presence of a reducing agent, and a nitrogen treatment step of including nitrogen in the evening powder or the niobium powder.
  • a eutectic salt such as KC 1-KF or KC 1-NaC 1 is usually heated to 800 to 900 ° C. and melted in a dilute salt to form a tantalum compound or a niobium compound.
  • the reducing agent are aliquoted little by little or continuously charged and reacted.
  • the diluted salt is cooled, and the obtained agglomerate is repeatedly washed with water, a weakly acidic aqueous solution, etc. to remove the diluted salt, and the tantalum powder or the niobium powder is removed. obtain.
  • separation operations such as centrifugation and filtration may be performed in combination, or the particles may be washed and purified with a solution in which hydrofluoric acid and hydrogen peroxide are dissolved.
  • the tantalum compound or niobium compound used as a raw material is not particularly limited, and compounds of these metals can be used, but potassium fluoride salts and halides are preferable.
  • the potassium fluoride salt, K 2 T a F 7, K 2 N b F 7, K 2 N b F 6 , and examples of the halides, niobium pentachloride, lower niobium chloride, Goshio tantalum, Chloride such as lower tantalum chloride, iodide, bromide and the like can be mentioned.
  • niobium compounds include niobium fluoride such as potassium fluoroniobate and oxides such as niobium pentoxide.
  • Examples of the reducing agent include alkali metals and alkaline earth metals such as sodium, magnesium and calcium, and hydrides thereof, ie, magnesium hydride, calcium hydride and the like.
  • the amount of the diluting salt is preferably set to be about 2 to 10 times the mass of the total mass of the tantalum compound or the niobium compound and the reducing agent. If the amount of the diluting salt is less than twice, the reaction rate is high because the concentration of the tantalum compound or the niobium compound as the raw material is high, and the particle size of the generated tantalum particles may be too large. on the other hand, If the amount of the dilute salt exceeds 10 times, the reaction rate will decrease and the productivity will decrease.
  • the tantalum powder or niobium powder obtained in the reduction step is heated in a vacuum at 800 to 140, for 0.5 to 2 hours to heat coagulate, and the powder is stored in the powder.
  • the existing ultra-fine particles are considered to be relatively large secondary particles.
  • a preliminary aggregation step of adding an amount of water to uniformly wet the entire powder may be performed while applying vibration to the tantalum powder or the niobium powder. By performing this preliminary aggregation step, a stronger aggregate can be obtained. Also, by adding about 10 to 300 ppm of phosphorus, boron, etc. to the metal in advance to the water added in the pre-aggregation step, fusion growth of primary particles is suppressed and a high surface area is maintained. It can be thermally agglomerated while heating. Examples of the form of phosphorus added here include phosphoric acid, phosphorus hexafluoride and the like.
  • the cake-like powder obtained in the heat coagulation process is crushed in the air or in an inert gas, and then heated in the presence of a reducing agent such as magnesium, sodium, calcium, etc., to reduce oxygen in the particles and oxygen.
  • a deoxygenation step of reacting the reducing agent is performed.
  • the deoxygenation step is performed in an atmosphere of an inert gas such as argon at a temperature not lower than the melting point of the reducing agent and not higher than the boiling point for 1 to 3 hours.
  • an inert gas such as argon
  • the tantalum powder or the niobium powder is moved in a nitrogen-containing atmosphere and heated while being brought into contact with nitrogen to perform a nitrogen treatment step of causing the tantalum powder or the niobium powder to contain nitrogen.
  • the method of moving the tantalum powder or the niobium powder in a nitrogen-containing atmosphere is not particularly limited, and a rotary kiln or a fluidized bed heating furnace can be used, but a rotary kiln is preferably used.
  • a rotary kiln is preferably used.
  • the inside of the rotary kiln is set to a nitrogen-containing atmosphere, and then the rotary kiln is rotated and the temperature is raised.
  • the contents in the rotary kiln are sufficiently brought into contact with nitrogen, and a nitrogen-containing powder is obtained.
  • by monitoring the partial pressure of nitrogen during the nitrogen treatment process it is possible to observe how the tantalum powder or niobium powder absorbs nitrogen.
  • the tantalum powder or niobium powder in a nitrogen-containing atmosphere using a rotary kiln or the like and heating while sufficiently contacting the nitrogen, the variation in the nitrogen content among the particles can be suppressed.
  • the volume in the rotary kiln used is preferably about 5 to 50 times the volume of the tantalum powder or niobium powder to be charged.
  • the number of revolutions of the rotary kiln is not particularly limited, but is usually about 0.5 to 5 rpm.
  • the nitrogen-containing atmosphere is preferably a nitrogen atmosphere or an inert atmosphere in which nitrogen is diluted with an inert gas other than nitrogen, such as argon or helium.
  • the nitrogen content of the tantalum powder or niobium powder can be arbitrarily adjusted by changing the nitrogen partial pressure in the nitrogen-containing atmosphere or adjusting the nitrogen treatment time and temperature.
  • the heating conditions in the nitrogen treatment step are not particularly limited, but usually, the tantalum powder or the niobium powder is heated to about 800 to 100,000 at a heating rate of 3 to 30 / min. Then, keep at this temperature for about 1 to 6 hours, and then cool to about room temperature. When the temperature of the contents reaches about room temperature, air is introduced into the rotary kiln and a gradual oxidation process is performed to form a stable film on the surface of the tantalum or niobium particles. After that, the contents are taken out, washed with an acid and pure water to remove the remaining reducing agent and substances derived from the reducing agent used in the deoxidizing step, and then dried.
  • the nitrogen treatment step may be performed at any time, not only after the deoxidation step, but also in the reduction step. It may be performed after or after the thermal aggregation step.
  • the nitrogen treatment step can be performed during the deoxidation step without separately performing the deoxidation step and the nitrogen treatment step.
  • the number of steps can be reduced as compared with the case where the deoxidation step and the nitrogen treatment step are separately performed, and the nitrogen-containing tantalum powder and the nitrogen-containing niob powder can be efficiently produced. Industrially more preferred.
  • a mixture of a tantalum powder or a niobium powder and a reducing agent added is charged into a rotary kiln, and a nitrogen-containing gas is sealed in the rotary kiln. Then, while rotating the rotary kiln, heat at a heating rate of about 3 to 30 "CZmin.
  • the surface of the tantalum powder or niobium powder grains is covered with an oxide film.
  • the oxide film rapidly diffuses due to the action of the reducing agent to expose tantalum or niobium, and the exposed tantalum or niobium comes into contact with nitrogen, absorbs nitrogen, and removes nitrogen.
  • stop heating and allow to cool After heating to about 800 to 100, and if necessary, maintaining at that temperature for 1 to 6 hours, stop heating and allow to cool.
  • a mixture obtained by adding a reducing agent to tantalum powder or niobium powder is charged into a rotary kiln, and an inert gas other than nitrogen such as argon is filled in the rotary kiln, and the rotary kiln is filled.
  • an inert gas other than nitrogen such as argon
  • the temperature is gradually lowered, and when the temperature becomes about 200 to 500, the inside of the rotary kiln is replaced with a nitrogen-containing gas and kept at this temperature for a certain time.
  • nitrogen is absorbed by tantalum or niobium to obtain a tantalum powder or a niobium powder containing nitrogen.
  • stop heating and allow to cool are examples of the inside of the rotary kiln.
  • the nitrogen-containing gas may be passed through without being enclosed in the rotary kiln.
  • a mixture obtained by adding a reducing agent to tantalum powder or niobium powder is placed in a sample dish or the like, and left standing in a furnace maintained in a nitrogen-containing atmosphere and heated, so that the nitrogen treatment step is performed during the deoxidation step. Do. Then, immediately after the start of the temperature rise, the particle surface of the tantalum powder or niobium powder is covered with an oxide film, and when the temperature reaches about 600, the oxide film rapidly diffuses to expose tantalum or niobium. Therefore, when the temperature exceeds 600, the exothermic reaction between nitrogen and tantalum or niobium in the uppermost layer in contact with nitrogen rapidly progresses, while nitrogen is not supplied to the lower layer powder at a sufficient speed. State. As a result, the powder in the upper layer of the sample dish has a very high nitrogen content, and the powder in the lower layer of the sample dish has a very low nitrogen content, resulting in a very large variation in the nitrogen content between particles. .
  • a mixture of a tantalum powder or a niobium powder and a reducing agent added thereto is placed in a sample dish or the like, and left in a furnace kept in an argon atmosphere or the like, heated to perform a deoxidation step, and when the temperature is lowered thereafter, A nitrogen treatment step is performed by setting the inside of the system to a nitrogen-containing atmosphere. Then, after the oxide film is removed from the particle surface of the tantalum powder or niobium powder, the tantalum powder or niobium powder comes into contact with nitrogen, so that if the temperature in the system is reduced to about 450, it is relatively low. A tantalum powder or a niobium powder containing nitrogen uniformly is obtained. However, because the temperature in the system is low and the diffusion rate of nitrogen is low, it takes about 10 to several hours for nitrogen treatment to contain 500 to 300 ppm of nitrogen. Not suitable for
  • the nitrogen diffusion rate increases, but only the powder in the upper layer of the sample dish comes into contact with nitrogen and a runaway reaction occurs locally.
  • the nitrogen content in the upper layer powder and the lower layer powder in the sample dish fluctuated extremely, and nitride crystals such as Ta 2 N and Ta N were found in the powder in the upper layer of the sample dish. Will be generated.
  • Nitrogen-containing tantalum powder or nitrogen-containing nitrogen obtained by such a method In Bed powder, Painda one as 3-5 wt% of camphor (C, .H 1 6 ⁇ ) and the like by press molding by adding, then 1 0-3 0 min 1 2 0 0-1 5 0 0 It is heated to a certain degree and sintered to produce a porous sintered body.
  • a lead wire is embedded in a nitrogen-containing tantalum powder or a nitrogen-containing niobium powder, then press-molded and sintered to integrate the lead wire. Then, the pressure is raised to 20 to 60 V at a current density of 40 to 80 mAZg in an electrolytic solution such as phosphoric acid or nitric acid having a temperature of 30 to 90 and a concentration of about 0.1% by mass. Then, the mixture is treated for 1 to 3 hours, and then subjected to chemical oxidation to form an anode electrode for a solid electrolytic capacitor.
  • an electrolytic solution such as phosphoric acid or nitric acid having a temperature of 30 to 90 and a concentration of about 0.1% by mass.
  • a solid electrolyte layer such as manganese dioxide, lead oxide or a conductive polymer, a graphite layer, and a silver paste layer are sequentially formed on the porous sintered body by a known method, and then a cathode terminal is soldered thereon. After connection, a resin jacket is formed to form a solid electrolytic capacitor.
  • Such a manufacturing method includes a nitrogen treatment step in which the tantalum powder or the niobium powder is heated in a nitrogen-containing atmosphere while being brought into contact with the nitrogen and heated to contain the nitrogen. Therefore, the tantalum powder or niobium powder is in uniform contact with nitrogen, contains 500 to 300 ppm of nitrogen, and the variation of the nitrogen content among the particles is suppressed to 100% or less. Nitrogen-containing tantalum powder or nitrogen-containing niobium powder can be stably produced.
  • the number of steps can be reduced as compared with the case where the deoxidation step and the nitrogen treatment step are performed separately, and the nitrogen-containing tantalum powder and the nitrogen-containing Can produce niobium powder and is more industrially preferred.
  • the tantalum powder obtained by reducing potassium tantalum fluoride (K 2 TaF 7 ) with sodium is heated to 1400 ° C in a vacuum to cause thermal coagulation, and the obtained cake-like powder is crushed.
  • K 2 TaF 7 potassium tantalum fluoride
  • 975 g of this tantalum powder was mixed with 25 g of magnesium powder, and 1 kg of the obtained mixture was charged into a rotary kiln having an internal volume of 6 L.
  • the kiln is rotated at 1 rpm to move the mixture particles, and the heating rate is increased to 85 Ot. After heating at in. and holding at 850 for 4 hours, heating was stopped and allowed to cool.
  • the nitrogen treatment step was performed during the deoxidation step.
  • the partial pressure of nitrogen gas was adjusted as shown in Table 1.
  • the average nitrogen content and the variation in the nitrogen content were determined as follows. (1) Average nitrogen content
  • An oxygen and nitrogen analyzer (HOR IBA ⁇ EMGA520) was used for the combustion gas component determination method.
  • the obtained nitrogen-containing tantalum powder was post-treated in the same manner as in Example 1 to produce a nitrogen-containing tantalum powder having an average nitrogen content shown in Table 1.
  • Table 1 also shows the variation in nitrogen content.
  • a sintered body was produced from these nitrogen-containing tantalum powders in the same manner as in Example 1, and the CV measurement and the breakdown voltage (BDV) measurement were performed in the same manner as in Example 1. Further, the density ratio D s / D g was calculated in the same manner as in Example 1. These characteristics are shown in Table 1 and FIGS.
  • the tantalum powder obtained by reducing potassium tantalum fluoride (K 2 TaF 7 ) with sodium is heated to 1400 in a vacuum to thermally coagulate, and the cake-like powder obtained is obtained.
  • the powder was crushed and pulverized to obtain a tantalum powder having a nominal CV value of 50000 F VZg.
  • 975 g of this tantalum powder was mixed with 25 g of magnesium powder, and 1 kg of the obtained mixture was charged into a rotary kiln having an internal volume of 6 L.
  • the kiln was rotated at 1 rpm to move the mixture particles and heated to 850 ° C at a heating rate of 6 ° CZmin.
  • the heating was stopped to lower the temperature.
  • the inside of the kiln reached 300 ° C
  • the inside of the kiln was replaced with a mixed gas of nitrogen gas and argon gas while the temperature was maintained at 300 ° C, and the kiln was deoxygenated. A nitrogen treatment step was performed during.
  • Example 1 From this nitrogen-containing tantalum powder, a sintered body was manufactured in the same manner as in Example 1, and the CV measurement and the breakdown voltage (BDV) measurement were performed in the same manner as in Example 1. Further, the density ratio Ds / Dg was calculated in the same manner as in Example 1. Table 1 and Figure 2 show these characteristics.
  • a nitrogen treatment step was performed during the deoxidation step in the same manner as in Example 5 except that the temperature of the nitrogen treatment step was changed to 450.
  • Example 1 the obtained nitrogen-containing tantalum powder was post-treated in the same manner as in Example 1 to produce a nitrogen-containing tantalum powder having an average nitrogen content shown in Table 1.
  • Table 1 also shows the variation in nitrogen content.
  • Example 7 From this nitrogen-containing tantalum powder, a sintered body was manufactured in the same manner as in Example 1, and the CV measurement and the breakdown voltage (BDV) measurement were performed in the same manner as in Example 1. Further, the density ratio Ds / Dg was calculated in the same manner as in Example 1. These characteristics are shown in Table 1 and Figure 2. [Example 7]
  • the tantalum powder obtained by reducing potassium tantalum fluoride (K 2 Ta F 7 ) with sodium is heated to 1400 in a vacuum to thermally coagulate, and the resulting cake-like powder is crushed. It was pulverized to obtain a tantalum powder having a nominal CV value of 50000 FV / g. Then, 975 g of this tantalum powder was mixed with 25 g of magnesium powder, and 1 kg of the obtained mixture was charged into a rotary kiln having an internal volume of 6 L. Then, after filling the kiln with argon gas, the kiln was rotated at 1 rpm to move the mixture particles, and the mixture was heated to 85 Ot: at a heating rate e Zmin.
  • the heating was stopped to lower the temperature, and when the inside of the kiln reached 500 ° C, while maintaining the temperature at 500 ° C, nitrogen gas with a flow rate of about 120 ml Zmin was passed through the kiln for 30 minutes. Thereafter, the nitrogen gas was stopped and the temperature was maintained for another 30 minutes, and a nitrogen treatment step was performed during the deoxidation step.
  • the obtained nitrogen-containing tantalum powder was post-treated in the same manner as in Example 1 to produce a nitrogen-containing tantalum powder having an average nitrogen content shown in Table 1. Also, the variation in nitrogen content
  • a sintered body was manufactured from this nitrogen-containing tantalum powder in the same manner as in Example 1, and the CV measurement and the breakdown voltage (BDV) measurement were performed in the same manner as in Example 1. Further, the density ratio D 3/08 was calculated in the same manner as in Example 1. Table 1 and Figure 2 show these characteristics.
  • the nitrogen treatment step was performed during the deoxidation step in the same manner as in Example 7, except that the flow rate of the nitrogen gas circulated in the nitrogen treatment step was 250 m 1 Zmin.
  • the obtained nitrogen-containing tantalum powder was post-treated in the same manner as in Example 1 to produce a nitrogen-containing tantalum powder having an average nitrogen content shown in Table 1.
  • Table 1 also shows the variation in nitrogen content.
  • Example 6 From this nitrogen-containing tantalum powder, a sintered body was manufactured in the same manner as in Example 1, and the CV measurement and the breakdown voltage (BDV) measurement were performed in the same manner as in Example 1. Further, the density ratio Ds / Dg was calculated in the same manner as in Example 1. These characteristics are shown in Table 1 and Figure 2. You. [Comparative Example 6]
  • the obtained nitrogen-containing tantalum powder was post-treated in the same manner as in Example 1 to produce a nitrogen-containing tantalum powder having an average nitrogen content shown in Table 1.
  • Table 1 also shows the variation in nitrogen content.
  • Example 1 From this nitrogen-containing tantalum powder, a sintered body was manufactured in the same manner as in Example 1, and the CV measurement and the breakdown voltage (BDV) measurement were performed in the same manner as in Example 1. Further, the density ratio D s / D g was calculated in the same manner as in Example 1. Table 1 and Figure 2 show these characteristics.
  • the obtained nitrogen-containing tantalum powder was post-treated in the same manner as in Example 1 to produce a nitrogen-containing tantalum powder having an average nitrogen content shown in Table 1.
  • Table 1 also shows the variation in nitrogen content.
  • tu3 ⁇ 4 ⁇ indicates ⁇ 3 ⁇ 4 kiln.
  • the tantalum powder obtained in the example has a small density ratio before and after sintering, and suppresses excessive shrinkage due to sintering, making it suitable for forming a solid electrolyte. Had voids.
  • the tantalum powder obtained in the comparative example had a large shrinkage due to sintering, and was not suitable for forming a solid electrolyte.
  • the tantalum powder obtained in the example has a large breakdown voltage (BDV) and uniform pores, so that it is possible to perform positive oxidation to a high voltage. You can see that.
  • the tantalum powder obtained in the comparative example had a low breakdown voltage (B DV) and did not have uniform pores suitable for forming a solid electrolyte.
  • the nitrogen-containing evening powder or the nitrogen-containing niobium powder of the present invention is fine, has a large surface area, and contains nitrogen uniformly. Therefore, when this is sintered, the sintering speed at the time of sintering is moderately suppressed, the progress of sintering is easily controlled appropriately, and a porous sintered body with a uniform size and distribution of pores is obtained. Can be. Such a porous sintered body is most suitable for use as the anode electrode of a high CV capacitor.
  • the production method of the present invention includes a nitrogen treatment step of heating the tantalum powder or the niobium powder while moving in a nitrogen-containing atmosphere, so that the nitrogen-containing powder is fine, has a large surface area, and has a uniform nitrogen content. Even powder or nitrogen-containing niobium powder can be produced stably. Furthermore, by performing the nitrogen treatment step during the deoxygenation treatment step, it is possible to efficiently produce nitrogen-containing tantalum powder or nitrogen-containing niobium powder in a small number of steps. ...

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  • Powder Metallurgy (AREA)

Abstract

Poudre de tantale ou de niobium contenant de l'azote et possédant une teneur en azote de 500 à 30 000 ppm, la différence de la teneur en azote entre deux particules prises au hasard étant égale ou supérieure à 100 %. On peut préparer cette poudre au moyen d'un procédé comprenant une étape de traitement d'azote consistant à réchauffer la poudre de tantale ou de niobium par agitation dans une atmosphère azotée afin d'incorporer l'azote dans la poudre. On empêche le frittage de cette poudre à une vitesse excessivement rapide, de sorte qu'il est facile de contrôler de façon adéquate l'étape de frittage. Ceci permet de fabriquer un produit fritté poreux dont la répartition et la dimension des pores sont régulières, ainsi qu'un condensateur présentant une capacité volumique élevée.
PCT/JP2001/005998 2000-07-12 2001-07-11 Poudre metallique contenant de l'azote, son procede de preparation, condensateur electrolytique solide et agglomere poreux fabrique au moyen de cette poudre metallique WO2002004152A1 (fr)

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JP2000-211825 2000-07-12
JP2000211825A JP2002030301A (ja) 2000-07-12 2000-07-12 窒素含有金属粉末およびその製造方法ならびにそれを用いた多孔質焼結体および固体電解コンデンサ

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US7083935B2 (en) 2001-01-17 2006-08-01 Veterans General Hospital Androgen receptor complex-associated protein
US9393623B2 (en) 2009-02-13 2016-07-19 Metalysis Limited Method for producing metal powders

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JP4187953B2 (ja) * 2001-08-15 2008-11-26 キャボットスーパーメタル株式会社 窒素含有金属粉末の製造方法
DE602005011773D1 (de) 2004-04-15 2009-01-29 Jfe Mineral Co Ltd Tantalpulver und dieses verwendender festelektrolytkondensator
EP1761352B1 (fr) * 2004-06-24 2008-08-13 H.C. Starck Inc. Production de poudres de metaux valves presentant de meilleures proprietes physiques et electriques
WO2006062234A1 (fr) * 2004-12-10 2006-06-15 Cabot Supermetals K.K. Procédé de fabrication d’une poudre métallique, procédé de fabrication d’un corps fritté poreux, poudre métallique et condensateur
JP5105879B2 (ja) * 2004-12-10 2012-12-26 キャボットスーパーメタル株式会社 金属粉末および多孔質焼結体の製造方法
CN100528418C (zh) * 2008-01-11 2009-08-19 宁夏东方钽业股份有限公司 含氮均匀的阀金属粉末及其制造方法,阀金属坯块和阀金属烧结体以及电解电容器的阳极
JP5697940B2 (ja) * 2010-10-20 2015-04-08 グローバルアドバンストメタルジャパン株式会社 タンタル粉体、その製造方法および脱酸素方法
JP6367356B2 (ja) * 2013-12-10 2018-08-01 ニンシア オリエント タンタル インダストリー カンパニー、 リミテッド 高窒素含有量を有するコンデンサグレードのタンタル粉末の調製方法、その方法により調製したコンデンサグレードのタンタル粉末、並びにタンタル粉末から調製したアノード及びコンデンサ
US20190308247A1 (en) * 2016-07-13 2019-10-10 Ningxia Orient Tantalum Industry Co., Ltd. Flaked tantalum powder and preparation method thereof

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JPH0617101A (ja) * 1992-04-24 1994-01-25 Asahi Chem Ind Co Ltd 均一窒化方法
EP0665302A2 (fr) * 1994-01-26 1995-08-02 H.C. Starck, INC. Procédé par l'obtention de poudres de nitrure de tantale
EP0953847A1 (fr) * 1997-02-28 1999-11-03 Showa Denko Kabushiki Kaisha Condensateur

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JPH0617101A (ja) * 1992-04-24 1994-01-25 Asahi Chem Ind Co Ltd 均一窒化方法
EP0665302A2 (fr) * 1994-01-26 1995-08-02 H.C. Starck, INC. Procédé par l'obtention de poudres de nitrure de tantale
EP0953847A1 (fr) * 1997-02-28 1999-11-03 Showa Denko Kabushiki Kaisha Condensateur

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7083935B2 (en) 2001-01-17 2006-08-01 Veterans General Hospital Androgen receptor complex-associated protein
US9393623B2 (en) 2009-02-13 2016-07-19 Metalysis Limited Method for producing metal powders
US9579725B2 (en) 2009-02-13 2017-02-28 Metalysis Limited Method for producing metal powders

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