WO2013186970A1 - Capacitor element and method for manufacturing same - Google Patents
Capacitor element and method for manufacturing same Download PDFInfo
- Publication number
- WO2013186970A1 WO2013186970A1 PCT/JP2013/002408 JP2013002408W WO2013186970A1 WO 2013186970 A1 WO2013186970 A1 WO 2013186970A1 JP 2013002408 W JP2013002408 W JP 2013002408W WO 2013186970 A1 WO2013186970 A1 WO 2013186970A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- dielectric layer
- tungsten
- capacitor element
- anode body
- observed
- Prior art date
Links
- 239000003990 capacitor Substances 0.000 title claims abstract description 57
- 238000004519 manufacturing process Methods 0.000 title claims description 7
- 238000000034 method Methods 0.000 title description 18
- 239000010410 layer Substances 0.000 claims abstract description 133
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims abstract description 71
- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 47
- 239000010937 tungsten Substances 0.000 claims abstract description 47
- 239000013078 crystal Substances 0.000 claims abstract description 42
- QGLKJKCYBOYXKC-UHFFFAOYSA-N nonaoxidotritungsten Chemical compound O=[W]1(=O)O[W](=O)(=O)O[W](=O)(=O)O1 QGLKJKCYBOYXKC-UHFFFAOYSA-N 0.000 claims abstract description 24
- 229910001930 tungsten oxide Inorganic materials 0.000 claims abstract description 22
- 239000007788 liquid Substances 0.000 claims abstract description 17
- 239000007864 aqueous solution Substances 0.000 claims abstract description 11
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims abstract description 10
- 229910017604 nitric acid Inorganic materials 0.000 claims abstract description 10
- 239000002344 surface layer Substances 0.000 claims abstract description 5
- 238000002441 X-ray diffraction Methods 0.000 claims description 9
- 239000000126 substance Substances 0.000 description 36
- 238000006243 chemical reaction Methods 0.000 description 34
- 239000000843 powder Substances 0.000 description 25
- 239000000243 solution Substances 0.000 description 18
- 239000007787 solid Substances 0.000 description 16
- 229910052751 metal Inorganic materials 0.000 description 14
- 239000002184 metal Substances 0.000 description 14
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- 230000015572 biosynthetic process Effects 0.000 description 12
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 11
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 10
- 238000000921 elemental analysis Methods 0.000 description 10
- 229910052760 oxygen Inorganic materials 0.000 description 10
- 239000001301 oxygen Substances 0.000 description 10
- 239000002245 particle Substances 0.000 description 9
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 8
- 238000010304 firing Methods 0.000 description 8
- 239000008187 granular material Substances 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 7
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 7
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- 238000010438 heat treatment Methods 0.000 description 6
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 6
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- 229910052757 nitrogen Inorganic materials 0.000 description 5
- 229910052698 phosphorus Inorganic materials 0.000 description 5
- 239000011574 phosphorus Substances 0.000 description 5
- 239000011148 porous material Substances 0.000 description 5
- 239000002994 raw material Substances 0.000 description 5
- 229910052715 tantalum Inorganic materials 0.000 description 5
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- 229910000147 aluminium phosphate Inorganic materials 0.000 description 4
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- 238000002156 mixing Methods 0.000 description 3
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- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
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- 150000007513 acids Chemical class 0.000 description 2
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- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 229910052797 bismuth Inorganic materials 0.000 description 2
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- 229920001940 conductive polymer Polymers 0.000 description 2
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- 238000001035 drying Methods 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 229910052735 hafnium Inorganic materials 0.000 description 2
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- 230000001771 impaired effect Effects 0.000 description 2
- 238000003475 lamination Methods 0.000 description 2
- NUJOXMJBOLGQSY-UHFFFAOYSA-N manganese dioxide Chemical compound O=[Mn]=O NUJOXMJBOLGQSY-UHFFFAOYSA-N 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 229910052750 molybdenum Inorganic materials 0.000 description 2
- 239000011733 molybdenum Substances 0.000 description 2
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 238000010298 pulverizing process Methods 0.000 description 2
- 239000011863 silicon-based powder Substances 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- PCCVSPMFGIFTHU-UHFFFAOYSA-N tetracyanoquinodimethane Chemical compound N#CC(C#N)=C1C=CC(=C(C#N)C#N)C=C1 PCCVSPMFGIFTHU-UHFFFAOYSA-N 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- -1 tungsten halide Chemical class 0.000 description 2
- ZNOKGRXACCSDPY-UHFFFAOYSA-N tungsten trioxide Chemical compound O=[W](=O)=O ZNOKGRXACCSDPY-UHFFFAOYSA-N 0.000 description 2
- DZKDPOPGYFUOGI-UHFFFAOYSA-N tungsten(iv) oxide Chemical compound O=[W]=O DZKDPOPGYFUOGI-UHFFFAOYSA-N 0.000 description 2
- 229910052720 vanadium Inorganic materials 0.000 description 2
- GPPXJZIENCGNKB-UHFFFAOYSA-N vanadium Chemical compound [V]#[V] GPPXJZIENCGNKB-UHFFFAOYSA-N 0.000 description 2
- 229910052725 zinc Inorganic materials 0.000 description 2
- 239000011701 zinc Substances 0.000 description 2
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- YMMGRPLNZPTZBS-UHFFFAOYSA-N 2,3-dihydrothieno[2,3-b][1,4]dioxine Chemical compound O1CCOC2=C1C=CS2 YMMGRPLNZPTZBS-UHFFFAOYSA-N 0.000 description 1
- GKWLILHTTGWKLQ-UHFFFAOYSA-N 2,3-dihydrothieno[3,4-b][1,4]dioxine Chemical compound O1CCOC2=CSC=C21 GKWLILHTTGWKLQ-UHFFFAOYSA-N 0.000 description 1
- JAJIPIAHCFBEPI-UHFFFAOYSA-N 9,10-dioxoanthracene-1-sulfonic acid Chemical compound O=C1C2=CC=CC=C2C(=O)C2=C1C=CC=C2S(=O)(=O)O JAJIPIAHCFBEPI-UHFFFAOYSA-N 0.000 description 1
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- 150000003863 ammonium salts Chemical class 0.000 description 1
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- 229910044991 metal oxide Inorganic materials 0.000 description 1
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- 235000006408 oxalic acid Nutrition 0.000 description 1
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- 150000003657 tungsten Chemical class 0.000 description 1
- WQJQOUPTWCFRMM-UHFFFAOYSA-N tungsten disilicide Chemical compound [Si]#[W]#[Si] WQJQOUPTWCFRMM-UHFFFAOYSA-N 0.000 description 1
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- CMPGARWFYBADJI-UHFFFAOYSA-L tungstic acid Chemical compound O[W](O)(=O)=O CMPGARWFYBADJI-UHFFFAOYSA-L 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
- H01G9/004—Details
- H01G9/04—Electrodes or formation of dielectric layers thereon
- H01G9/048—Electrodes or formation of dielectric layers thereon characterised by their structure
- H01G9/052—Sintered electrodes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
- H01G9/0029—Processes of manufacture
- H01G9/0032—Processes of manufacture formation of the dielectric layer
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
- H01G9/004—Details
- H01G9/07—Dielectric layers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
- H01G9/004—Details
- H01G9/04—Electrodes or formation of dielectric layers thereon
- H01G9/048—Electrodes or formation of dielectric layers thereon characterised by their structure
- H01G9/052—Sintered electrodes
- H01G9/0525—Powder therefor
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
- H01G9/15—Solid electrolytic capacitors
Definitions
- the present invention relates to a capacitor element and a manufacturing method thereof. More specifically, the present invention relates to a capacitor element having at least an anode body containing tungsten and a dielectric layer containing tungsten oxide, and a method for manufacturing the same.
- Capacitor elements obtained by electrolytically oxidizing an anode body made of a sintered body of valve action metal powders such as tantalum and niobium and converting the surface layer of the sintered body into a dielectric made of a metal oxide are known.
- Various techniques for improving tantalum capacitor elements or niobium capacitor elements have also been proposed.
- Tungsten is known as a kind of valve action metal.
- An electrolytic capacitor using a sintered body of tungsten powder as an anode body has a larger capacity than an electrolytic capacitor obtained by forming an anode body of the same volume using tantalum powder of the same particle diameter at the same conversion voltage.
- LC leakage current
- use of an alloy of tungsten and another metal for reducing the leakage current has been studied (Patent Document 1), but the effect of reducing the leakage current is small.
- An object of the present invention is to provide a capacitor element having a small leakage current, and a manufacturing method thereof, having an anode body containing tungsten and a dielectric layer containing tungsten oxide.
- tungsten on the surface of the sintered body is oxidized to form a dielectric layer.
- tungsten oxide is crystallized in the process of forming the dielectric layer, and a lump 13 having a flat surface as shown in FIG. 5 is generated.
- the dielectric layer generated by this chemical conversion treatment is not a sufficiently dense film having an appropriate thickness, and seems to have a large number of defects through which a current can flow when a voltage is applied. Therefore, a solid electrolytic capacitor having a dielectric layer made of such crystalline tungsten oxide has a large leakage current.
- the present inventors diligently studied to achieve the above object.
- the present invention includes the following aspects.
- It has at least an anode body containing tungsten and a dielectric layer formed on the surface of the anode body and containing tungsten oxide, and the dielectric layer is substantially crystallized in a scanning electron microscope.
- Capacitor elements not observed in [2] A capacitor element having at least an anode body containing tungsten and a dielectric layer on the surface of the anode body and containing amorphous tungsten oxide.
- It has at least an anode body containing tungsten and a dielectric layer formed on the surface of the anode body and containing tungsten oxide, and the dielectric layer is a crystal of tungsten oxide in X-ray diffraction. Capacitor element in which no derived diffraction peak is observed.
- FIG. 2 is a diagram showing an X-ray diffraction peak of a sintered body having a dielectric layer on the surface obtained in Example 1.
- FIG. 2 is a diagram showing an X-ray diffraction peak of a sintered body having a dielectric layer on the surface obtained in Example 1.
- FIG. It is a figure which shows the scanning electron micrograph of the surface of the sintered compact which has a dielectric material layer on the surface obtained in the comparative example 1.
- FIG. It is a figure which shows the X-ray-diffraction peak of the sintered compact which has a dielectric material layer on the surface obtained in the comparative example 1.
- the capacitor element according to an embodiment of the present invention includes at least an anode body containing tungsten and a dielectric layer that is on the surface of the anode body and contains tungsten oxide.
- the capacitor element according to one embodiment of the present invention preferably has an anode body 1 made of tungsten and a dielectric layer 2 made of tungsten oxide, as shown in FIG.
- a preferred form of the anode body comprises one having a shape in which one granular material and another granular material are connected to each other in a bead shape. It is.
- the granular material is mainly tungsten described later.
- the conductivity between the granular materials is ensured by the continuous connection of the granular materials.
- the anode body is preferably a sintered body of tungsten powder.
- the tungsten powder used in the present invention may be a powder of a single tungsten metal or a powder of a tungsten alloy.
- Tungsten used for the anode body is not particularly limited, and may be a commercially available product. Solid tungsten metal is commercially available in the form of powders, lumps, bars and the like.
- the tungsten used for the anode body may be manufactured as follows. For example, the tungsten powder adjusted to a desired particle diameter can be obtained by crushing tungsten trioxide powder in a hydrogen stream.
- tungsten powder adjusted to a desired particle diameter can be obtained by reducing tungstic acid or tungsten halide using a reducing agent such as hydrogen or sodium. Furthermore, tungsten powder can be obtained from a tungsten-containing mineral through a known process.
- the tungsten used in the present invention preferably has an oxygen content of 0.05 to 8% by mass, more preferably 0.08 to 1% by mass.
- the tungsten alloy include alloys of tungsten and metals such as tantalum, niobium, aluminum, titanium, vanadium, zinc, molybdenum, hafnium, zirconium, and bismuth.
- Tungsten may be one in which at least a part of its surface is silicided, borated, phosphorylated and / or carbonized, or a mixture containing at least one of them. Further, tungsten and the mixture may contain nitrogen on at least a part of the surface thereof.
- Silicided tungsten can be obtained, for example, by mixing tungsten powder with silicon powder and heating it under reduced pressure to react. According to this method, tungsten silicide such as W 5 Si 3 is formed in the surface layer usually within 50 nm from the tungsten particle surface.
- the tungsten containing nitrogen can be obtained, for example, by placing tungsten powder at 350 to 1500 ° C. under reduced pressure and passing nitrogen gas for several minutes to several hours. Nitrogen-containing treatment may be performed at the time of high-temperature treatment when silicifying tungsten powder, or silicidation may be performed after the treatment is performed first.
- Carbonized tungsten can be obtained, for example, by placing tungsten powder in a carbon electrode furnace at 300 to 1500 ° C. under reduced pressure for several minutes to several hours. When nitrogen is passed in a carbon electrode furnace under predetermined conditions, nitrogen absorption occurs at the same time as carbonization, and a tungsten powder having a part of the surface containing nitrogen and carbonized can be obtained.
- Boronized tungsten can be obtained, for example, by mixing a boron source such as a simple substance of boron or a compound containing boron element with tungsten powder, and heating and reacting it under reduced pressure.
- Phosphorylated tungsten can be obtained, for example, by mixing phosphorus powder with a phosphorus source such as phosphorus alone or a compound containing phosphorus element, and heating the mixture under reduced pressure for reaction.
- the tungsten powder preferably has an average primary particle size of 0.1 to 1 ⁇ m, more preferably 0.1 to 0.7 ⁇ m, and still more preferably 0.1 to 0.3 ⁇ m.
- the tungsten powder may be a granulated powder.
- the granulated powder can be produced by sintering and pulverizing ungranulated tungsten powder. Further, the granulated powder may be produced by sintering and pulverizing the granulated powder once produced.
- the particle diameter of the granulated powder is preferably 20 to 170 ⁇ m, more preferably 26 to 140 ⁇ m.
- the anode body may contain a metal other than tungsten.
- a metal other than tungsten examples include tantalum, niobium, aluminum, titanium, vanadium, zinc, molybdenum, hafnium, zirconium, and bismuth.
- the amount of tungsten element contained in the anode body is preferably 50% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more.
- the sintered body is obtained by pressing and solidifying a raw material powder made of tungsten powder and, if necessary, another metal powder to obtain a molded body, and firing it in a furnace.
- a binder may be mixed with the raw material powder.
- Various conditions such as the amount of powder and the molding apparatus can be appropriately set so as to obtain a desired molding density.
- an anode lead wire is embedded in a molded body and planted to form a terminal of the anode body.
- a metal wire such as tungsten, tantalum, or niobium can be used.
- an anode lead wire is later welded to the sintered body.
- a metal plate or metal foil may be planted or connected to the sintered body instead of the metal wire.
- the temperature during firing is preferably 1300 to 1700 ° C, more preferably 1400 to 1600 ° C.
- the firing time is preferably 10 to 50 minutes, more preferably 15 to 30 minutes.
- the atmosphere during firing is not particularly limited, but is preferably reduced. Note that the above-described silicidation, borideization, phosphation or carbonization, and / or nitrogen-containing treatment can be performed during firing.
- the dielectric layer is made of an amorphous tungsten oxide, a crystal in which a crystal is not substantially observed in a scanning electron microscope, or a diffraction peak derived from a tungsten oxide crystal is not observed in an X-ray diffraction. .
- the surface of the tungsten anode body is covered all the way to the back of the pores 5 with a bowl-shaped dielectric layer shown in FIG. 2 or 3.
- “crystals are not substantially observed” means that the number of lumps (crystals) 13 having a flat surface (crystal surface) as shown in FIG. 5 is 100 ⁇ m 2 in a scanning electron microscope. It means 10 or less.
- tungsten oxide crystal examples include WO 2 monoclinic crystal, WO 2.72 monoclinic crystal, WO 2.9 crystal, and WO 3 orthorhombic crystal. In the present invention, these crystals are not observed in a scanning electron microscope or detected in X-ray diffraction.
- the dielectric layer can be made to have a desired withstand voltage by adjusting the formation voltage.
- the dielectric layer 2 preferably has a plurality of protrusions 3 on its surface. It is preferable that the protrusion has a hook shape.
- the hook-shaped protrusions may be arranged substantially in parallel, or may form a branch, a cross, and / or a loop.
- the height of the protrusion is preferably not less than 0.1 times and less than 3 times the thickness of the dielectric layer.
- the ratio of the full width at half maximum of the protrusion to the height of the protrusion is preferably 1 or less, more preferably 0.5 or less.
- the dielectric layer can be produced by chemical conversion treatment.
- the chemical conversion treatment is performed under the following conditions. First, in the chemical conversion treatment, an aqueous solution containing nitric acid is used as a chemical conversion solution.
- the amount of nitric acid contained in the chemical conversion liquid is preferably 0.05 to 0.5% by mass, more preferably 0.1 to 0.2% by mass.
- the temperature of the chemical conversion liquid is 30 ° C. or less, preferably 0 to 20 ° C., more preferably 5 to 20 ° C.
- the chemical conversion liquid may contain other electrolytes as long as the effects of the present invention are not impaired.
- Examples of other electrolytes include acids such as sulfuric acid, boric acid, oxalic acid, adipic acid, and phosphoric acid; or alkali metal salts and ammonium salts of these acids.
- the chemical conversion liquid may contain an oxidizing agent that supplies oxygen such as hydrogen peroxide and ozone as long as the effects of the present invention are not impaired.
- the said sintered compact is immersed in the said chemical conversion liquid, and a voltage is applied.
- the voltage is applied between the sintered body (anode) and the counter electrode (cathode).
- Energization of the sintered body can be performed through the anode lead wire.
- the voltage application is started at an initial current density of 9 to 300 mA / g, preferably 9 to 180 mA / g, more preferably 25 to 180 mA / g, and the current density value is maintained at a predetermined voltage. It is preferable to maintain the voltage value after reaching (the formation voltage).
- the formation voltage can be appropriately set according to a desired withstand voltage.
- the voltage application time can be appropriately set according to the size of the sintered body and the initial current density, but is preferably 3 to 11 hours, more preferably 5 to 10 hours, and further preferably 5 to 7 hours.
- tungsten on the surface of the sintered body is oxidized, and a dielectric layer containing tungsten oxide is generated.
- the sintered body is washed with pure water and then dried.
- the drying is not particularly limited as long as the temperature and time allow the water adhering to the sintered body to evaporate. You may heat-process in order to dry.
- the heat treatment is preferably performed at 250 ° C. or lower, more preferably 160 ° C. to 230 ° C.
- the heat treatment time is not particularly limited as long as the stability of the dielectric layer can be maintained, and is preferably 10 minutes to 2 hours, more preferably 20 minutes to 60 minutes.
- the chemical conversion treatment may be performed again after the heat treatment.
- the re-chemical conversion treatment can be performed under the same conditions as the first chemical conversion treatment. After the re-chemical conversion treatment, pure water washing and drying can be performed as described above.
- the cathode used in the conventional solid electrolytic capacitor can be used without limitation.
- the cathode include an inorganic or organic semiconductive layer.
- the inorganic semiconductive layer include a molybdenum dioxide layer, a tungsten dioxide layer, a lead dioxide layer, and a manganese dioxide layer.
- the organic semiconductive layer is composed of a tetracyanoquinodimethane (TCNQ) complex salt layer or a layer composed of polypyrrole or a derivative thereof, polythiophene or a derivative thereof (for example, a polymer of 3,4-ethylenedioxythiophene).
- Examples thereof include conductive polymer layers such as a layer, a layer made of polysulfide or a derivative thereof, a layer made of polyfuran or a derivative thereof, a layer made of polyaniline or a derivative thereof, and the like. Furthermore, a conductive layer such as a carbon paste layer, a silver paste layer, or a metal plating layer may be formed on the organic or inorganic semiconductive layer.
- a cathode lead is electrically connected to the cathode, and the cathode lead is exposed outside the exterior of the electrolytic capacitor and becomes a cathode external terminal.
- an anode lead is electrically connected to the anode body via an anode lead wire, and the anode lead is exposed outside the exterior of the electrolytic capacitor and becomes an anode external terminal.
- a normal lead frame can be used to attach the cathode lead and the anode lead. Subsequently, the exterior can be formed by sealing with a resin or the like to obtain a capacitor.
- the capacitor thus produced can be subjected to an aging process as desired.
- the capacitor according to the present invention can be used by being mounted on various electric circuits or electronic circuits.
- Example 1 (Production of sintered body) Ammonium tungstate was reduced with hydrogen to obtain a tungsten primary powder having an average particle size of 0.6 ⁇ m. This powder was mixed with 0.5% by mass of silicon powder having an average particle diameter of 1 ⁇ m, and then heated at 1450 ° C. for 30 minutes under reduced pressure. The temperature was returned to room temperature, and the lump was pulverized with a hammer mill to produce granulated powder having an average particle size of 120 ⁇ m (particle size distribution range: 20 to 220 ⁇ m). It was confirmed by elemental analysis that the granulated powder contained 0.5% by mass of silicon element.
- the granulated powder and a binder were mixed.
- a molded body having a density of 7.8 g / cm 3 was produced from the mixture using a TAP-2R molding machine manufactured by Seken. During the molding, a 0.29 mm ⁇ tungsten wire (anode lead wire) was embedded and 8 mm outside was planted. The obtained molded body was put into a vacuum firing furnace and the temperature was gradually raised. The binder was removed during the temperature increase. Sintering was performed at a temperature of 1540 ° C. for 30 minutes. Thereafter, the temperature was lowered to room temperature. A plurality of sintered bodies having a size of 1.0 mm ⁇ 1.5 mm ⁇ 4.5 mm and a mass of 55 mg were produced.
- the dielectric layer was observed with a scanning electron microscope JSM-7500FA manufactured by JEOL Ltd. As shown in FIG. 2 and FIG. 3, the anode body has a shape in which one granular material and another granular material are interlaced with each other and connected in a bead shape. There was a hole), and a sufficiently dense dielectric layer having an appropriate thickness was formed on the surface. The thickness of the dielectric layer varies depending on the location, but is generally in the range of 30 to 50 nm. On the surface of the dielectric layer, there were ridge-like projections that were branched, crossed, or looped. In addition, a lump (crystal) having a flat surface (crystal surface) as shown in FIG. 5 was not observed in the dielectric layer. According to elemental analysis, the dielectric layer contained tungsten and oxygen. According to X-ray diffraction, no diffraction peak derived from the tungsten oxide crystal was detected (see FIG. 4).
- Electrolytic polymerization step The obtained treated body was immersed in a 20% by mass EDTH ethanol solution. The ethanol solution was pulled up. Then, it immersed in the polymerization liquid with the liquid temperature of 20 degreeC stored by the stainless steel (SUS303) container to the predetermined position, and electropolymerized at 10 microampere for 60 minutes.
- the polymerization solution is obtained by dissolving EDTH 0.4% by mass and anthraquinonesulfonic acid 0.6% by mass in a solvent composed of 70 parts by mass of water and 30 parts by mass of ethylene glycol. After completion of the electropolymerization, the polymer solution was pulled up, washed with pure water and ethanol, and then dried. A semiconductive layer made of a conductive polymer was laminated on the surface of the dielectric layer.
- the treatment body on which the semiconductive layer was formed was immersed in the chemical conversion liquid.
- Application of voltage was started at an initial current density of 1.8 mA / g at a liquid temperature of 20 ° C., and the current density value was maintained. After reaching 6.5 V, the voltage was maintained at 6.5 V for 15 minutes. A voltage was applied. It was pulled out from the chemical conversion liquid, washed with pure water and ethanol, and then dried.
- the above-mentioned dipping step-electrolytic polymerization step-post-chemical conversion step was further repeated 7 times (8 times in total).
- the current value during the electropolymerization was set to 20 ⁇ A for the second time, 30 ⁇ A for the third time, and 50 ⁇ A for the fourth to eighth times.
- a carbon paste was applied to a predetermined portion of the treated body on which the semiconductive layer was formed and dried to form a carbon paste layer.
- a silver paste was applied on the carbon paste layer and dried to form a silver paste layer. In this way, a plurality of solid electrolytic capacitor elements were produced.
- Example 2 A solid electrolytic capacitor element was produced in the same manner as in Example 1 except that the initial current density at the time of forming the dielectric layer was changed to 180 mA / g and the voltage application time was changed to 5 hours. The dielectric layer was observed with a scanning electron microscope. A dielectric layer as shown in FIGS. 2 and 3 was produced. On the surface of the dielectric layer, there were ridge-like projections that were branched, crossed, or looped. In addition, a lump (crystal) having a flat surface (crystal surface) as shown in FIG. 5 was not observed in the dielectric layer. According to elemental analysis, the dielectric layer contained tungsten and oxygen.
- Example 3 A solid electrolytic capacitor element was produced in the same manner as in Example 1 except that the initial current density at the time of forming the dielectric layer was changed to 90 mA / g and the voltage application time was changed to 5 hours. The dielectric layer was observed with a scanning electron microscope. A dielectric layer as shown in FIGS. 2 and 3 was produced. On the surface of the dielectric layer, there were ridge-like projections that were branched, crossed, or looped. In addition, a lump (crystal) having a flat surface (crystal surface) as shown in FIG. 5 was not observed in the dielectric layer. According to elemental analysis, the dielectric layer contained tungsten and oxygen.
- Example 4 A solid electrolytic capacitor element was produced in the same manner as in Example 1 except that the initial current density during the formation of the dielectric layer was changed to 18 mA / g. The dielectric layer was observed with a scanning electron microscope. A dielectric layer as shown in FIGS. 2 and 3 was produced. On the surface of the dielectric layer, there were ridge-like projections that were branched, crossed, or looped. In addition, a lump (crystal) having a flat surface (crystal surface) as shown in FIG. 5 was not observed in the dielectric layer. According to elemental analysis, the dielectric layer contained tungsten and oxygen.
- Example 5 Solid electrolysis was performed in the same manner as in Example 1 except that the concentration and temperature of nitric acid in the chemical conversion solution were changed to 0.2% by mass and 10 ° C., and the initial current density was changed to 9 mA / g. A capacitor element was produced. The dielectric layer was observed with a scanning electron microscope. A dielectric layer as shown in FIGS. 2 and 3 was produced. On the surface of the dielectric layer, there were ridge-like projections that were branched, crossed, or looped. In addition, a lump (crystal) having a flat surface (crystal surface) as shown in FIG. 5 was not observed in the dielectric layer. According to elemental analysis, the dielectric layer contained tungsten and oxygen.
- Example 6 A solid electrolytic capacitor element was produced in the same manner as in Example 1 except that silicon was not added when the granulated powder was produced.
- the dielectric layer was observed with a scanning electron microscope.
- a dielectric layer as shown in FIGS. 2 and 3 was produced. On the surface of the dielectric layer, there were ridge-like projections that were branched, crossed, or looped.
- a lump (crystal) having a flat surface (crystal surface) as shown in FIG. 5 was not observed in the dielectric layer. According to elemental analysis, the dielectric layer contained tungsten and oxygen.
- Example 7 When producing granulated powder, the solid electrolytic capacitor element was produced by the same method as Example 1 except having added 0.2 mass% of phosphoric acid to the tungsten powder used as a raw material. The granulated powder was confirmed by elemental analysis to contain 0.5% by mass of silicon element and 270 ppm of phosphorus element. The dielectric layer was observed with a scanning electron microscope. A dielectric layer as shown in FIGS. 2 and 3 was produced. On the surface of the dielectric layer, there were ridge-like projections that were branched, crossed, or looped. In addition, a lump (crystal) having a flat surface (crystal surface) as shown in FIG. 5 was not observed in the dielectric layer. According to elemental analysis, the dielectric layer contained tungsten and oxygen.
- Example 8 The nitric acid concentration and temperature of the aqueous nitric acid solution were changed to 0.2% by mass and 0 ° C., the initial current density was changed to 55 mA / g, and the voltage application time was changed to 10 hours when forming the dielectric layer.
- a solid electrolytic capacitor element was produced in the same manner as in Example 1. The dielectric layer was observed with a scanning electron microscope. A dielectric layer as shown in FIGS. 2 and 3 was produced. On the surface of the dielectric layer, there were ridge-like projections that were branched, crossed, or looped. In addition, a lump (crystal) having a flat surface (crystal surface) as shown in FIG. 5 was not observed in the dielectric layer. According to elemental analysis, the dielectric layer contained tungsten and oxygen.
- Comparative Example 1 The chemical solution at the time of dielectric layer formation and post-formation was changed to 0.1% by mass phosphoric acid aqueous solution, the temperature of the chemical solution at the time of dielectric layer formation was changed to 65 ° C., and the initial current density was 1.8 mA.
- a solid electrolytic capacitor element was produced in the same manner as in Example 1 except that the amount was changed to / g.
- the dielectric layer was observed with a scanning electron microscope. As shown in FIG. 5, in the dielectric layer, a lump (crystal) having a flat surface (crystal surface) was observed in a number of more than 10 in a field of 100 ⁇ m 2 observed with a scanning electron microscope.
- Comparative Example 2 The same method as in Example 1 except that the formation solution at the time of forming the dielectric layer and the post-formation was changed to 1.0 mass% phosphoric acid aqueous solution, and the temperature of the formation solution at the time of forming the dielectric layer was changed to 25 ° C. A solid electrolytic capacitor element was produced. The dielectric layer was observed with a scanning electron microscope. In the dielectric layer, a lump (crystal) having a flat surface (crystal surface) similar to that in FIG. 5 was observed in a number of more than 10 in a 100 ⁇ m 2 field of view with a scanning electron microscope.
- Comparative Example 3 The same method as in Example 1 except that the chemical solution at the time of dielectric layer formation and post-formation was changed to 2.0 mass% sulfuric acid aqueous solution, and the liquid temperature of the chemical solution at the time of dielectric layer formation was changed to 35 ° C. A solid electrolytic capacitor element was produced. The dielectric layer was observed with a scanning electron microscope. In the dielectric layer, a lump (crystal) having a flat surface (crystal surface) similar to that in FIG. 5 was observed in a number of more than 10 in a 100 ⁇ m 2 field of view with a scanning electron microscope.
- Comparative Example 4 A solid electrolytic capacitor element was produced in the same manner as in Example 1 except that the temperature of the chemical conversion solution during the formation of the dielectric layer was changed to 80 ° C. and the initial current density was changed to 3.6 mA / g. The dielectric layer was observed with a scanning electron microscope. In the dielectric layer, a lump (crystal) having a flat surface (crystal surface) similar to that in FIG. 5 was observed in a number of more than 10 in a 100 ⁇ m 2 field of view with a scanning electron microscope.
- the capacitor element (Example) according to the present invention has very little leakage current.
- the capacitor element (comparative example) manufactured by the conventional chemical conversion treatment method has a large leakage current.
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Abstract
A capacitor element, which has small leakage current and comprises at least a positive electrode body containing tungsten and a dielectric layer that is present on the surface of the positive electrode body and is formed of an amorphous tungsten oxide, in said dielectric layer substantially no crystals being observed with a scanning electron microscope, is obtained by applying a voltage to a tungsten powder sintered body at an initial current density of 9-300 mA/g for 3-11 hours in an aqueous solution that contains 0.05-0.5% by mass of nitric acid at a liquid temperature of 30°C or less, thereby chemically converting the surface layer of the sintered body into a dielectric body.
Description
本発明は、コンデンサ素子およびその製造方法に関する。より詳細に、本発明は、タングステンを含有して成る陽極体とタングステン酸化物を含有して成る誘電体層とを少なくとも有するコンデンサ素子およびその製造方法に関する。
The present invention relates to a capacitor element and a manufacturing method thereof. More specifically, the present invention relates to a capacitor element having at least an anode body containing tungsten and a dielectric layer containing tungsten oxide, and a method for manufacturing the same.
コンデンサ素子として、タンタル、ニオブなどの弁作用金属粉の焼結体からなる陽極体を電解酸化して、該焼結体表面層を金属酸化物からなる誘電体に化成することによって得られるものが知られている。また、タンタルコンデンサ素子またはニオブコンデンサ素子の改良技術も種々提案されている。
弁作用金属の一種としてタングステンが知られている。タングステン粉の焼結体を陽極体とする電解コンデンサは、同一粒子径のタンタル粉を用いた同体積の陽極体を同化成電圧で化成して得られる電解コンデンサに比較して、大きな容量を得ることができるが、漏れ電流(LC)が大きいために実用に供されていない。また、漏れ電流の低減のためにタングステンと他の金属との合金を用いることが検討されている(特許文献1)が、漏れ電流を減らす効果は僅かである。 Capacitor elements obtained by electrolytically oxidizing an anode body made of a sintered body of valve action metal powders such as tantalum and niobium and converting the surface layer of the sintered body into a dielectric made of a metal oxide Are known. Various techniques for improving tantalum capacitor elements or niobium capacitor elements have also been proposed.
Tungsten is known as a kind of valve action metal. An electrolytic capacitor using a sintered body of tungsten powder as an anode body has a larger capacity than an electrolytic capacitor obtained by forming an anode body of the same volume using tantalum powder of the same particle diameter at the same conversion voltage. However, it is not put into practical use due to the large leakage current (LC). In addition, use of an alloy of tungsten and another metal for reducing the leakage current has been studied (Patent Document 1), but the effect of reducing the leakage current is small.
弁作用金属の一種としてタングステンが知られている。タングステン粉の焼結体を陽極体とする電解コンデンサは、同一粒子径のタンタル粉を用いた同体積の陽極体を同化成電圧で化成して得られる電解コンデンサに比較して、大きな容量を得ることができるが、漏れ電流(LC)が大きいために実用に供されていない。また、漏れ電流の低減のためにタングステンと他の金属との合金を用いることが検討されている(特許文献1)が、漏れ電流を減らす効果は僅かである。 Capacitor elements obtained by electrolytically oxidizing an anode body made of a sintered body of valve action metal powders such as tantalum and niobium and converting the surface layer of the sintered body into a dielectric made of a metal oxide Are known. Various techniques for improving tantalum capacitor elements or niobium capacitor elements have also been proposed.
Tungsten is known as a kind of valve action metal. An electrolytic capacitor using a sintered body of tungsten powder as an anode body has a larger capacity than an electrolytic capacitor obtained by forming an anode body of the same volume using tantalum powder of the same particle diameter at the same conversion voltage. However, it is not put into practical use due to the large leakage current (LC). In addition, use of an alloy of tungsten and another metal for reducing the leakage current has been studied (Patent Document 1), but the effect of reducing the leakage current is small.
本発明の目的は、タングステンを含有して成る陽極体とタングステン酸化物を含有して成る誘電体層とを有する、漏れ電流の少ないコンデンサ素子およびその製造方法を提供することである。
An object of the present invention is to provide a capacitor element having a small leakage current, and a manufacturing method thereof, having an anode body containing tungsten and a dielectric layer containing tungsten oxide.
タングステン粉の焼結体を化成処理すると、焼結体表面のタングステンが酸化されて誘電体層が生成する。従来の化成処理法によると、誘電体層の生成過程において、タングステン酸化物が結晶化し、図5に示すような、平らな面を有する塊13が生成する。この化成処理によって生成する誘電体層は、適切な厚みを持つ十分に緻密な被膜となっておらず、電圧印加時に電流が流れうる多数の欠陥を持つようである。よって、このような結晶性タングステン酸化物からなる誘電体層を有する固体電解コンデンサは漏れ電流が多い。
本発明者らは、上記目的を達成するために鋭意検討した。その結果、タングステン粉の焼結体をある特定の条件で化成処理すると、非晶質なタングステン酸化物を含有して成る誘電体層を生成でき、そのような誘電体層を有するコンデンサは漏れ電流が極めて少ないことを見出した。本発明はこの知見に基づいて完成するに至ったものである。 When the tungsten powder sintered body is subjected to chemical conversion treatment, tungsten on the surface of the sintered body is oxidized to form a dielectric layer. According to the conventional chemical conversion treatment method, tungsten oxide is crystallized in the process of forming the dielectric layer, and alump 13 having a flat surface as shown in FIG. 5 is generated. The dielectric layer generated by this chemical conversion treatment is not a sufficiently dense film having an appropriate thickness, and seems to have a large number of defects through which a current can flow when a voltage is applied. Therefore, a solid electrolytic capacitor having a dielectric layer made of such crystalline tungsten oxide has a large leakage current.
The present inventors diligently studied to achieve the above object. As a result, when a sintered body of tungsten powder is subjected to chemical conversion treatment under certain conditions, a dielectric layer containing amorphous tungsten oxide can be generated, and a capacitor having such a dielectric layer has a leakage current. Found that there was very little. The present invention has been completed based on this finding.
本発明者らは、上記目的を達成するために鋭意検討した。その結果、タングステン粉の焼結体をある特定の条件で化成処理すると、非晶質なタングステン酸化物を含有して成る誘電体層を生成でき、そのような誘電体層を有するコンデンサは漏れ電流が極めて少ないことを見出した。本発明はこの知見に基づいて完成するに至ったものである。 When the tungsten powder sintered body is subjected to chemical conversion treatment, tungsten on the surface of the sintered body is oxidized to form a dielectric layer. According to the conventional chemical conversion treatment method, tungsten oxide is crystallized in the process of forming the dielectric layer, and a
The present inventors diligently studied to achieve the above object. As a result, when a sintered body of tungsten powder is subjected to chemical conversion treatment under certain conditions, a dielectric layer containing amorphous tungsten oxide can be generated, and a capacitor having such a dielectric layer has a leakage current. Found that there was very little. The present invention has been completed based on this finding.
すなわち、本発明は以下の態様を包含する。
〔1〕 タングステンを含有して成る陽極体と、陽極体表面に在り且つタングステン酸化物を含有して成る誘電体層とを少なくとも有し、 誘電体層は、走査型電子顕微鏡において結晶が実質的に観察されない、コンデンサ素子。
〔2〕 タングステンを含有して成る陽極体と、陽極体表面に在り且つ非晶質タングステン酸化物を含有して成る誘電体層とを少なくとも有するコンデンサ素子。
〔3〕 タングステンを含有して成る陽極体と、陽極体表面に在り且つタングステン酸化物を含有して成る誘電体層とを少なくとも有し、 誘電体層は、X線回折においてタングステン酸化物の結晶由来の回折ピークが観測されない、コンデンサ素子。 That is, the present invention includes the following aspects.
[1] It has at least an anode body containing tungsten and a dielectric layer formed on the surface of the anode body and containing tungsten oxide, and the dielectric layer is substantially crystallized in a scanning electron microscope. Capacitor elements not observed in
[2] A capacitor element having at least an anode body containing tungsten and a dielectric layer on the surface of the anode body and containing amorphous tungsten oxide.
[3] It has at least an anode body containing tungsten and a dielectric layer formed on the surface of the anode body and containing tungsten oxide, and the dielectric layer is a crystal of tungsten oxide in X-ray diffraction. Capacitor element in which no derived diffraction peak is observed.
〔1〕 タングステンを含有して成る陽極体と、陽極体表面に在り且つタングステン酸化物を含有して成る誘電体層とを少なくとも有し、 誘電体層は、走査型電子顕微鏡において結晶が実質的に観察されない、コンデンサ素子。
〔2〕 タングステンを含有して成る陽極体と、陽極体表面に在り且つ非晶質タングステン酸化物を含有して成る誘電体層とを少なくとも有するコンデンサ素子。
〔3〕 タングステンを含有して成る陽極体と、陽極体表面に在り且つタングステン酸化物を含有して成る誘電体層とを少なくとも有し、 誘電体層は、X線回折においてタングステン酸化物の結晶由来の回折ピークが観測されない、コンデンサ素子。 That is, the present invention includes the following aspects.
[1] It has at least an anode body containing tungsten and a dielectric layer formed on the surface of the anode body and containing tungsten oxide, and the dielectric layer is substantially crystallized in a scanning electron microscope. Capacitor elements not observed in
[2] A capacitor element having at least an anode body containing tungsten and a dielectric layer on the surface of the anode body and containing amorphous tungsten oxide.
[3] It has at least an anode body containing tungsten and a dielectric layer formed on the surface of the anode body and containing tungsten oxide, and the dielectric layer is a crystal of tungsten oxide in X-ray diffraction. Capacitor element in which no derived diffraction peak is observed.
〔4〕 誘電体層はその表面に複数の突起を有する、〔1〕~〔3〕のいずれかひとつに記載のコンデンサ素子。
〔5〕 突起の高さが誘電体層の厚さの0.1倍以上3倍未満である、〔4〕に記載のコンデンサ素子。
〔6〕 誘電体層はその表面に高さに対する半値全幅の比が1以下である突起を少なくとも有する、〔1〕~〔3〕のいずれかひとつに記載のコンデンサ素子。 [4] The capacitor element according to any one of [1] to [3], wherein the dielectric layer has a plurality of protrusions on a surface thereof.
[5] The capacitor element according to [4], wherein the height of the protrusion is not less than 0.1 times and less than 3 times the thickness of the dielectric layer.
[6] The capacitor element according to any one of [1] to [3], wherein the dielectric layer has at least a protrusion having a ratio of a full width at half maximum to a height of 1 or less on a surface thereof.
〔5〕 突起の高さが誘電体層の厚さの0.1倍以上3倍未満である、〔4〕に記載のコンデンサ素子。
〔6〕 誘電体層はその表面に高さに対する半値全幅の比が1以下である突起を少なくとも有する、〔1〕~〔3〕のいずれかひとつに記載のコンデンサ素子。 [4] The capacitor element according to any one of [1] to [3], wherein the dielectric layer has a plurality of protrusions on a surface thereof.
[5] The capacitor element according to [4], wherein the height of the protrusion is not less than 0.1 times and less than 3 times the thickness of the dielectric layer.
[6] The capacitor element according to any one of [1] to [3], wherein the dielectric layer has at least a protrusion having a ratio of a full width at half maximum to a height of 1 or less on a surface thereof.
〔7〕 タングステンを含有して成る陽極体がタングステン焼結体である、〔1〕~〔6〕のいずれかひとつに記載のコンデンサ素子。
〔8〕 〔1〕~〔7〕のいずれかひとつに記載のコンデンサ素子を含有するコンデンサ。 [7] The capacitor element according to any one of [1] to [6], wherein the anode body containing tungsten is a tungsten sintered body.
[8] A capacitor containing the capacitor element according to any one of [1] to [7].
〔8〕 〔1〕~〔7〕のいずれかひとつに記載のコンデンサ素子を含有するコンデンサ。 [7] The capacitor element according to any one of [1] to [6], wherein the anode body containing tungsten is a tungsten sintered body.
[8] A capacitor containing the capacitor element according to any one of [1] to [7].
〔9〕 硝酸0.05~0.5質量%を含む液温30℃以下の水溶液中で、タングステン粉の焼結体に、初期電流密度9~300mA/gにて3~11時間電圧印加して、該焼結体表面層を誘電体に化成することを含む、〔1〕~〔7〕のいずれかひとつに記載のコンデンサ素子の製造方法。
[9] In an aqueous solution containing 0.05 to 0.5 mass% nitric acid at a liquid temperature of 30 ° C. or less, a voltage was applied to the sintered tungsten powder for 3 to 11 hours at an initial current density of 9 to 300 mA / g The method for manufacturing a capacitor element according to any one of [1] to [7], comprising forming the sintered body surface layer into a dielectric.
本発明によると、高容量でありながら、漏れ電流が極めて少ないタングステン製のコンデンサ素子またはコンデンサを得ることができる。
According to the present invention, it is possible to obtain a capacitor element or a capacitor made of tungsten having a very small leakage current while having a high capacity.
本発明の一実施形態に係るコンデンサ素子は、タングステンを含有して成る陽極体と、陽極体表面に在り且つタングステン酸化物を含有して成る誘電体層とを少なくとも有する。本発明の一実施形態に係るコンデンサ素子は、破断面が図2に示すような、タングステンからなる陽極体1と、タングステン酸化物からなる誘電体層2とを有することが好ましい。
The capacitor element according to an embodiment of the present invention includes at least an anode body containing tungsten and a dielectric layer that is on the surface of the anode body and contains tungsten oxide. The capacitor element according to one embodiment of the present invention preferably has an anode body 1 made of tungsten and a dielectric layer 2 made of tungsten oxide, as shown in FIG.
好適な形態の陽極体は、図1に示すように、一つの粒状物と他の一つの粒状物とが相互に相貫して数珠状に繋がった形状を有するもの6を含有して成るものである。当該粒状物は主に後述するタングステンである。粒状物が相貫して繋がることによって粒状物間の導電性が確保される。数珠状に繋がった粒状物の間には細孔が在る。
As shown in FIG. 1, a preferred form of the anode body comprises one having a shape in which one granular material and another granular material are connected to each other in a bead shape. It is. The granular material is mainly tungsten described later. The conductivity between the granular materials is ensured by the continuous connection of the granular materials. There are pores between the granular materials connected in a bead shape.
陽極体は、タングステン粉の焼結体であることが好ましい。本発明に使用されるタングステン粉はタングステン金属単体の粉であってもよいし、タングステン合金の粉であってもよい。陽極体に使用されるタングステンは、特に制限されず、市販品であってもよい。固形タングステン金属は、粉、塊、棒などの形態で市販されている。また、陽極体に使用されるタングステンは、次のようにして製造したものであってもよい。例えば、三酸化タングステン粉を水素気流中で解砕することによって、所望の粒子径に調整されたタングステン粉を得ることができる。また、タングステン酸やハロゲン化タングステンを水素やナトリウムなどの還元剤を使用して還元することによって、所望の粒子径に調整されたタングステン粉を得ることができる。さらに、タングステン含有鉱物から公知の工程を経てタングステン粉を得ることができる。本発明に使用されるタングステンは、酸素含有量が、0.05~8質量%であることが好ましく、0.08~1質量%であることがより好ましい。タングステン合金としては、タングステンと、タンタル、ニオブ、アルミニウム、チタン、バナジウム、亜鉛、モリブデン、ハフニウム、ジルコニウム、ビスマスなどの金属との合金が挙げられる。
The anode body is preferably a sintered body of tungsten powder. The tungsten powder used in the present invention may be a powder of a single tungsten metal or a powder of a tungsten alloy. Tungsten used for the anode body is not particularly limited, and may be a commercially available product. Solid tungsten metal is commercially available in the form of powders, lumps, bars and the like. Moreover, the tungsten used for the anode body may be manufactured as follows. For example, the tungsten powder adjusted to a desired particle diameter can be obtained by crushing tungsten trioxide powder in a hydrogen stream. Moreover, tungsten powder adjusted to a desired particle diameter can be obtained by reducing tungstic acid or tungsten halide using a reducing agent such as hydrogen or sodium. Furthermore, tungsten powder can be obtained from a tungsten-containing mineral through a known process. The tungsten used in the present invention preferably has an oxygen content of 0.05 to 8% by mass, more preferably 0.08 to 1% by mass. Examples of the tungsten alloy include alloys of tungsten and metals such as tantalum, niobium, aluminum, titanium, vanadium, zinc, molybdenum, hafnium, zirconium, and bismuth.
タングステンは、その表面の少なくとも一部が、ケイ化、ホウ化、リン化および/または炭化されたもの、またはそれらのうちの少なくとも一つを含む混合物であってもよい。また、タングステンおよび該混合物は、その表面の少なくとも一部に窒素を含有していてもよい。
Tungsten may be one in which at least a part of its surface is silicided, borated, phosphorylated and / or carbonized, or a mixture containing at least one of them. Further, tungsten and the mixture may contain nitrogen on at least a part of the surface thereof.
ケイ化されたタングステンは、例えば、タングステン粉にケイ素粉を混ぜ合わせ、それを減圧下で加熱して反応させることにより得ることができる。この方法によると、タングステン粒子表面から通常50nm以内の表層に局在して、W5Si3などのケイ化タングステンが形成される。
窒素を含有するタングステンは、例えば、タングステン粉を減圧下に350~1500℃に置き、窒素ガスを数分間から数時間通じることによって得ることができる。窒素を含有させる処理は、タングステン粉をケイ化するときの高温処理時に行つてもよいし、先に該処理を行ってからケイ化を行つてもよい。 Silicided tungsten can be obtained, for example, by mixing tungsten powder with silicon powder and heating it under reduced pressure to react. According to this method, tungsten silicide such as W 5 Si 3 is formed in the surface layer usually within 50 nm from the tungsten particle surface.
The tungsten containing nitrogen can be obtained, for example, by placing tungsten powder at 350 to 1500 ° C. under reduced pressure and passing nitrogen gas for several minutes to several hours. Nitrogen-containing treatment may be performed at the time of high-temperature treatment when silicifying tungsten powder, or silicidation may be performed after the treatment is performed first.
窒素を含有するタングステンは、例えば、タングステン粉を減圧下に350~1500℃に置き、窒素ガスを数分間から数時間通じることによって得ることができる。窒素を含有させる処理は、タングステン粉をケイ化するときの高温処理時に行つてもよいし、先に該処理を行ってからケイ化を行つてもよい。 Silicided tungsten can be obtained, for example, by mixing tungsten powder with silicon powder and heating it under reduced pressure to react. According to this method, tungsten silicide such as W 5 Si 3 is formed in the surface layer usually within 50 nm from the tungsten particle surface.
The tungsten containing nitrogen can be obtained, for example, by placing tungsten powder at 350 to 1500 ° C. under reduced pressure and passing nitrogen gas for several minutes to several hours. Nitrogen-containing treatment may be performed at the time of high-temperature treatment when silicifying tungsten powder, or silicidation may be performed after the treatment is performed first.
炭化されたタングステンは、例えば、タングステン粉を、炭素電極炉中に減圧下300~1500℃に数分間から数時間置くことによって得ることができる。炭素電極炉で窒素を所定条件で通じると、炭化と同時に窒素の吸収が起こり、表面の一部が窒素を含有し且つ炭化された夕ングステン粉を得ることができる。
ホウ化されたタングステンは、例えば、タングステン粉にホウ素単体やホウ素元素を有する化合物などのホウ素源を混ぜ合わせ、それを減圧下で加熱して反応させることにより得ることができる。
リン化されたタングステンは、例えば、タングステン粉にリン単体やリン元素を有する化合物などのリン源を混ぜ合わせ、それを減圧下で加熱して反応させることにより得ることができる。 Carbonized tungsten can be obtained, for example, by placing tungsten powder in a carbon electrode furnace at 300 to 1500 ° C. under reduced pressure for several minutes to several hours. When nitrogen is passed in a carbon electrode furnace under predetermined conditions, nitrogen absorption occurs at the same time as carbonization, and a tungsten powder having a part of the surface containing nitrogen and carbonized can be obtained.
Boronized tungsten can be obtained, for example, by mixing a boron source such as a simple substance of boron or a compound containing boron element with tungsten powder, and heating and reacting it under reduced pressure.
Phosphorylated tungsten can be obtained, for example, by mixing phosphorus powder with a phosphorus source such as phosphorus alone or a compound containing phosphorus element, and heating the mixture under reduced pressure for reaction.
ホウ化されたタングステンは、例えば、タングステン粉にホウ素単体やホウ素元素を有する化合物などのホウ素源を混ぜ合わせ、それを減圧下で加熱して反応させることにより得ることができる。
リン化されたタングステンは、例えば、タングステン粉にリン単体やリン元素を有する化合物などのリン源を混ぜ合わせ、それを減圧下で加熱して反応させることにより得ることができる。 Carbonized tungsten can be obtained, for example, by placing tungsten powder in a carbon electrode furnace at 300 to 1500 ° C. under reduced pressure for several minutes to several hours. When nitrogen is passed in a carbon electrode furnace under predetermined conditions, nitrogen absorption occurs at the same time as carbonization, and a tungsten powder having a part of the surface containing nitrogen and carbonized can be obtained.
Boronized tungsten can be obtained, for example, by mixing a boron source such as a simple substance of boron or a compound containing boron element with tungsten powder, and heating and reacting it under reduced pressure.
Phosphorylated tungsten can be obtained, for example, by mixing phosphorus powder with a phosphorus source such as phosphorus alone or a compound containing phosphorus element, and heating the mixture under reduced pressure for reaction.
タングステン粉は、その平均一次粒子径が好ましくは0.1~1μm、より好ましくは0.1~0.7μm、さらに好ましくは0.1~0.3μmである。タングステン粉は、造粒粉であってもよい。造粒粉は未造粒のタングステン粉を焼結・粉砕するなどして製造することができる。また、造粒粉は、一旦製造した造粒粉を、再度、焼結・粉砕するなどして製造してもよい。造粒粉の粒子径は、好ましくは20~170μm、より好ましくは26~140μmである。
The tungsten powder preferably has an average primary particle size of 0.1 to 1 μm, more preferably 0.1 to 0.7 μm, and still more preferably 0.1 to 0.3 μm. The tungsten powder may be a granulated powder. The granulated powder can be produced by sintering and pulverizing ungranulated tungsten powder. Further, the granulated powder may be produced by sintering and pulverizing the granulated powder once produced. The particle diameter of the granulated powder is preferably 20 to 170 μm, more preferably 26 to 140 μm.
陽極体はタングステン以外の金属を含んでいてもよい。他の金属として、タンタル、ニオブ、アルミニウム、チタン、バナジウム、亜鉛、モリブデン、ハフニウム、ジルコニウム、ビスマスなどが挙げられる。陽極体に含まれるタングステン元素の量は、好ましくは50質量%以上、より好ましくは80質量%以上、さらに好ましくは90質量%以上である。
The anode body may contain a metal other than tungsten. Examples of other metals include tantalum, niobium, aluminum, titanium, vanadium, zinc, molybdenum, hafnium, zirconium, and bismuth. The amount of tungsten element contained in the anode body is preferably 50% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more.
焼結体は、タングステン粉および必要に応じて他の金属粉からなる原料粉を圧し固めて成形体を得、それを炉において焼成することによって得られる。加圧成形を容易にするためにバインダーを原料粉に混ぜてもよい。所望の成形密度などになるように粉量や成形装置などの諸条件を適宜設定することができる。原料粉を圧し固める際に、陽極体の端子とするために陽極リード線を成形体に埋設し植立させる方法がある。陽極リード線としてはタングステン、タンタル、ニオブなどの金属線などを用いることができる。また、焼結体に後から陽極リード線を溶接して接続する方法もある。金属線の代わりに金属板や金属箔を焼結体に植立または接続してもよい。
The sintered body is obtained by pressing and solidifying a raw material powder made of tungsten powder and, if necessary, another metal powder to obtain a molded body, and firing it in a furnace. In order to facilitate pressure molding, a binder may be mixed with the raw material powder. Various conditions such as the amount of powder and the molding apparatus can be appropriately set so as to obtain a desired molding density. When the raw material powder is pressed and hardened, there is a method in which an anode lead wire is embedded in a molded body and planted to form a terminal of the anode body. As the anode lead wire, a metal wire such as tungsten, tantalum, or niobium can be used. There is also a method in which an anode lead wire is later welded to the sintered body. A metal plate or metal foil may be planted or connected to the sintered body instead of the metal wire.
焼成時の温度は、好ましくは1300~1700℃、より好ましくは1400~1600℃である。焼成時間は、好ましくは10~50分間、より好ましくは15~30分間である。焼成が高温度または長時間すぎると、原料粉相互間の空間(細孔)が減り、細孔容積の小さい緻密な焼結体が得られやすい。焼成が低温度または短時間すぎると強度が不足し、場合によっては焼結体が崩壊することもある。焼成時の雰囲気は特に制限されないが、減圧とすることが好ましい。なお、焼成時に前述したケイ化、ホウ化、リン化または炭化、および/または窒素を含有させる処理を行うこともできる。
The temperature during firing is preferably 1300 to 1700 ° C, more preferably 1400 to 1600 ° C. The firing time is preferably 10 to 50 minutes, more preferably 15 to 30 minutes. When firing is performed at a high temperature or for a long time, the space (pores) between the raw material powders is reduced, and a dense sintered body having a small pore volume is easily obtained. When firing is performed at a low temperature or for a short time, the strength is insufficient, and in some cases, the sintered body may collapse. The atmosphere during firing is not particularly limited, but is preferably reduced. Note that the above-described silicidation, borideization, phosphation or carbonization, and / or nitrogen-containing treatment can be performed during firing.
誘電体層は、非晶質のタングステン酸化物からなるもの、走査型電子顕微鏡において結晶が実質的に観察されないもの、またはX線回折においてタングステン酸化物の結晶由来の回折ピークが観測されないものである。図1に示すように、タングステン陽極体の表面は、図2または3中に示す襞状の誘電体層で細孔5の奥の方までくまなく覆われている。ここで「結晶が実質的に観察されない」とは、図5に示すような平らな面(結晶面)を有する塊(結晶)13の数が走査型電子顕微鏡での100μm2の視野中に、10個以下であることを意味する。
タングステン酸化物の結晶としては、WO2単斜晶、WO2.72単斜晶、WO2.9晶、WO3斜方晶などがある。本発明においては、これら結晶が走査型電子顕微鏡において観察されず、またはX線回折において検出されない。 The dielectric layer is made of an amorphous tungsten oxide, a crystal in which a crystal is not substantially observed in a scanning electron microscope, or a diffraction peak derived from a tungsten oxide crystal is not observed in an X-ray diffraction. . As shown in FIG. 1, the surface of the tungsten anode body is covered all the way to the back of thepores 5 with a bowl-shaped dielectric layer shown in FIG. 2 or 3. Here, “crystals are not substantially observed” means that the number of lumps (crystals) 13 having a flat surface (crystal surface) as shown in FIG. 5 is 100 μm 2 in a scanning electron microscope. It means 10 or less.
Examples of the tungsten oxide crystal include WO 2 monoclinic crystal, WO 2.72 monoclinic crystal, WO 2.9 crystal, and WO 3 orthorhombic crystal. In the present invention, these crystals are not observed in a scanning electron microscope or detected in X-ray diffraction.
タングステン酸化物の結晶としては、WO2単斜晶、WO2.72単斜晶、WO2.9晶、WO3斜方晶などがある。本発明においては、これら結晶が走査型電子顕微鏡において観察されず、またはX線回折において検出されない。 The dielectric layer is made of an amorphous tungsten oxide, a crystal in which a crystal is not substantially observed in a scanning electron microscope, or a diffraction peak derived from a tungsten oxide crystal is not observed in an X-ray diffraction. . As shown in FIG. 1, the surface of the tungsten anode body is covered all the way to the back of the
Examples of the tungsten oxide crystal include WO 2 monoclinic crystal, WO 2.72 monoclinic crystal, WO 2.9 crystal, and WO 3 orthorhombic crystal. In the present invention, these crystals are not observed in a scanning electron microscope or detected in X-ray diffraction.
誘電体層は、化成電圧を調節することによって所望する耐電圧を有する厚さにすることができる。誘電体層2は、その表面に複数の突起3を有することが好ましい。突起は襞状を成していることが好ましい。襞状突起は略平行に並んでいてもよいし、分岐、交差および/またはループを成していてもよい。突起の高さは、誘電体層の厚さの0.1倍以上~3倍未満であることが好ましい。突起の高さに対する突起の半値全幅の比は、好ましくは1以下、より好ましくは0.5以下である。
The dielectric layer can be made to have a desired withstand voltage by adjusting the formation voltage. The dielectric layer 2 preferably has a plurality of protrusions 3 on its surface. It is preferable that the protrusion has a hook shape. The hook-shaped protrusions may be arranged substantially in parallel, or may form a branch, a cross, and / or a loop. The height of the protrusion is preferably not less than 0.1 times and less than 3 times the thickness of the dielectric layer. The ratio of the full width at half maximum of the protrusion to the height of the protrusion is preferably 1 or less, more preferably 0.5 or less.
誘電体層は、化成処理によって作製できる。化成処理は、次のとおりの条件で行う。まず、化成処理には、化成液として硝酸を含む水溶液を用いる。化成液に含まれる硝酸の量は、好ましくは0.05~0.5質量%、より好ましくは0.1~0.2質量%である。化成液の温度は、30℃以下、好ましくは0~20℃、より好ましくは5~20℃である。化成液には、本発明の効果を損なわない範囲で、他の電解質が含まれていてもよい。他の電解質としては、硫酸、ホウ酸、シュウ酸、アジピン酸、リン酸などの酸;またはそれら酸のアルカリ金属塩やアンモニウム塩などが挙げられる。また、化成液には、本発明の効果を損なわない範囲で、過酸化水素やオゾンなどの酸素を供給する酸化剤が含まれていてもよい。
The dielectric layer can be produced by chemical conversion treatment. The chemical conversion treatment is performed under the following conditions. First, in the chemical conversion treatment, an aqueous solution containing nitric acid is used as a chemical conversion solution. The amount of nitric acid contained in the chemical conversion liquid is preferably 0.05 to 0.5% by mass, more preferably 0.1 to 0.2% by mass. The temperature of the chemical conversion liquid is 30 ° C. or less, preferably 0 to 20 ° C., more preferably 5 to 20 ° C. The chemical conversion liquid may contain other electrolytes as long as the effects of the present invention are not impaired. Examples of other electrolytes include acids such as sulfuric acid, boric acid, oxalic acid, adipic acid, and phosphoric acid; or alkali metal salts and ammonium salts of these acids. Further, the chemical conversion liquid may contain an oxidizing agent that supplies oxygen such as hydrogen peroxide and ozone as long as the effects of the present invention are not impaired.
次に、当該化成液に前記焼結体を浸漬し、電圧を印加する。電圧は、焼結体(陽極)と対電極(陰極)との間に印加する。焼結体への通電は陽極リード線を通じて行うことができる。
電圧印加は、初期電流密度を9~300mA/gにて、好ましくは9~180mA/gにて、より好ましくは25~180mA/gにて開始し、該電流密度値を維持し、所定の電圧(化成電圧)に達した時からはその電圧値を維持することが好ましい。化成電圧は所望の耐電圧に応じて適宜設定することができる。
電圧印加時間は、焼結体の大きさや初期電流密度に応じて適宜設定できるが、好ましくは3~11時間、より好ましくは5~10時間、さらに好ましくは5~7時間である。
この化成処理によって焼結体表面のタングステンが酸化されて、タングステン酸化物を含有してなる誘電体層が生成する。 Next, the said sintered compact is immersed in the said chemical conversion liquid, and a voltage is applied. The voltage is applied between the sintered body (anode) and the counter electrode (cathode). Energization of the sintered body can be performed through the anode lead wire.
The voltage application is started at an initial current density of 9 to 300 mA / g, preferably 9 to 180 mA / g, more preferably 25 to 180 mA / g, and the current density value is maintained at a predetermined voltage. It is preferable to maintain the voltage value after reaching (the formation voltage). The formation voltage can be appropriately set according to a desired withstand voltage.
The voltage application time can be appropriately set according to the size of the sintered body and the initial current density, but is preferably 3 to 11 hours, more preferably 5 to 10 hours, and further preferably 5 to 7 hours.
By this chemical conversion treatment, tungsten on the surface of the sintered body is oxidized, and a dielectric layer containing tungsten oxide is generated.
電圧印加は、初期電流密度を9~300mA/gにて、好ましくは9~180mA/gにて、より好ましくは25~180mA/gにて開始し、該電流密度値を維持し、所定の電圧(化成電圧)に達した時からはその電圧値を維持することが好ましい。化成電圧は所望の耐電圧に応じて適宜設定することができる。
電圧印加時間は、焼結体の大きさや初期電流密度に応じて適宜設定できるが、好ましくは3~11時間、より好ましくは5~10時間、さらに好ましくは5~7時間である。
この化成処理によって焼結体表面のタングステンが酸化されて、タングステン酸化物を含有してなる誘電体層が生成する。 Next, the said sintered compact is immersed in the said chemical conversion liquid, and a voltage is applied. The voltage is applied between the sintered body (anode) and the counter electrode (cathode). Energization of the sintered body can be performed through the anode lead wire.
The voltage application is started at an initial current density of 9 to 300 mA / g, preferably 9 to 180 mA / g, more preferably 25 to 180 mA / g, and the current density value is maintained at a predetermined voltage. It is preferable to maintain the voltage value after reaching (the formation voltage). The formation voltage can be appropriately set according to a desired withstand voltage.
The voltage application time can be appropriately set according to the size of the sintered body and the initial current density, but is preferably 3 to 11 hours, more preferably 5 to 10 hours, and further preferably 5 to 7 hours.
By this chemical conversion treatment, tungsten on the surface of the sintered body is oxidized, and a dielectric layer containing tungsten oxide is generated.
化成処理の後、焼結体を純水で洗浄し、次いで乾燥する。乾燥は焼結体に付着した水を蒸散できる温度および時間であれば特に制限はない。乾燥するために熱処理を行ってもよい。熱処理は、好ましくは250℃以下、より好ましくは160℃~230℃で行う。熱処理の時間は、誘電体層の安定性が維持できる範囲であれば特に制限されず、好ましくは10分間~2時間、より好ましくは20分間~60分間である。熱処理の後に、化成処理を再度行ってもよい。再化成処理は、1回目の化成処理と同じ条件にて行うことができる。再化成処理の後は、上記と同様に、純水洗浄、乾燥を行うことができる。
After the chemical conversion treatment, the sintered body is washed with pure water and then dried. The drying is not particularly limited as long as the temperature and time allow the water adhering to the sintered body to evaporate. You may heat-process in order to dry. The heat treatment is preferably performed at 250 ° C. or lower, more preferably 160 ° C. to 230 ° C. The heat treatment time is not particularly limited as long as the stability of the dielectric layer can be maintained, and is preferably 10 minutes to 2 hours, more preferably 20 minutes to 60 minutes. The chemical conversion treatment may be performed again after the heat treatment. The re-chemical conversion treatment can be performed under the same conditions as the first chemical conversion treatment. After the re-chemical conversion treatment, pure water washing and drying can be performed as described above.
上記のような方法で得られた部材に陰極を取り付ける。陰極は従来の固体電解コンデンサに用いられているものが制限なく使用できる。陰極としては、例えば、無機または有機半導電体層が挙げられる。無機半導電体層としては、二酸化モリブデン層、二酸化タングステン層、二酸化鉛層または二酸化マンガン層などが挙げられる。有機半導電体層としては、テトラシアノキノジメタン(TCNQ)錯塩層またはポリピロールまたはそれの誘導体から成る層、ポリチオフェンまたはそれの誘導体(例えば、3,4-エチレンジオキシチオフェンの重合体)から成る層、ポリスルファイドまたはそれの誘導体から成る層、ポリフランまたはそれの誘導体から成る層、ポリアニリンまたはそれの誘導体から成る層などの導電性高分子層などが挙げられる。さらに前記有機又は無機の半導電体層上にカーボンペースト層や銀ペースト層、若しくは金属メッキ層などの導電体層を形成してもよい。
Attaching the cathode to the member obtained by the above method. The cathode used in the conventional solid electrolytic capacitor can be used without limitation. Examples of the cathode include an inorganic or organic semiconductive layer. Examples of the inorganic semiconductive layer include a molybdenum dioxide layer, a tungsten dioxide layer, a lead dioxide layer, and a manganese dioxide layer. The organic semiconductive layer is composed of a tetracyanoquinodimethane (TCNQ) complex salt layer or a layer composed of polypyrrole or a derivative thereof, polythiophene or a derivative thereof (for example, a polymer of 3,4-ethylenedioxythiophene). Examples thereof include conductive polymer layers such as a layer, a layer made of polysulfide or a derivative thereof, a layer made of polyfuran or a derivative thereof, a layer made of polyaniline or a derivative thereof, and the like. Furthermore, a conductive layer such as a carbon paste layer, a silver paste layer, or a metal plating layer may be formed on the organic or inorganic semiconductive layer.
上記陰極に陰極リードが電気的に接続され、該陰極リードが電解コンデンサの外装の外部に露出して陰極外部端子となる。一方、陽極体には、陽極リード線を介して陽極リードが電気的に接続され、該陽極リードが電解コンデンサの外装の外部に露出して陽極外部端子となる。陰極リードおよび陽極リードの取り付けには通常のリードフレームを用いることができる。次いで、樹脂などによる封止によって外装を形成してコンデンサを得ることができる。このようにして作成されたコンデンサは、所望によりエージング処理を行うことができる。本発明に係るコンデンサは、各種電気回路または電子回路に装着し、使用することができる。
A cathode lead is electrically connected to the cathode, and the cathode lead is exposed outside the exterior of the electrolytic capacitor and becomes a cathode external terminal. On the other hand, an anode lead is electrically connected to the anode body via an anode lead wire, and the anode lead is exposed outside the exterior of the electrolytic capacitor and becomes an anode external terminal. A normal lead frame can be used to attach the cathode lead and the anode lead. Subsequently, the exterior can be formed by sealing with a resin or the like to obtain a capacitor. The capacitor thus produced can be subjected to an aging process as desired. The capacitor according to the present invention can be used by being mounted on various electric circuits or electronic circuits.
以下に実施例を示し、本発明をより具体的に説明する。なお、これらは説明のための単なる例示であって、本発明はこれらによって何等制限されるものではない。
Hereinafter, the present invention will be described more specifically with reference to examples. Note that these are merely illustrative examples, and the present invention is not limited by these.
実施例1
〔焼結体の作製〕
タングステン酸アンモニウムを水素還元して平均粒子径0.6μmのタングステン一次粉を得た。この粉に平均粒子径1μmの珪素粉を0.5質量%混合し、その後、減圧下1450℃で、30分間加熱した。室温に戻し、塊状物をハンマーミルで解砕し、平均粒子径120μm(粒度分布範囲20~220μm)の造粒粉を作製した。造粒粉には珪素元素が0.5質量%入っていることを元素分析により確認した。 Example 1
(Production of sintered body)
Ammonium tungstate was reduced with hydrogen to obtain a tungsten primary powder having an average particle size of 0.6 μm. This powder was mixed with 0.5% by mass of silicon powder having an average particle diameter of 1 μm, and then heated at 1450 ° C. for 30 minutes under reduced pressure. The temperature was returned to room temperature, and the lump was pulverized with a hammer mill to produce granulated powder having an average particle size of 120 μm (particle size distribution range: 20 to 220 μm). It was confirmed by elemental analysis that the granulated powder contained 0.5% by mass of silicon element.
〔焼結体の作製〕
タングステン酸アンモニウムを水素還元して平均粒子径0.6μmのタングステン一次粉を得た。この粉に平均粒子径1μmの珪素粉を0.5質量%混合し、その後、減圧下1450℃で、30分間加熱した。室温に戻し、塊状物をハンマーミルで解砕し、平均粒子径120μm(粒度分布範囲20~220μm)の造粒粉を作製した。造粒粉には珪素元素が0.5質量%入っていることを元素分析により確認した。 Example 1
(Production of sintered body)
Ammonium tungstate was reduced with hydrogen to obtain a tungsten primary powder having an average particle size of 0.6 μm. This powder was mixed with 0.5% by mass of silicon powder having an average particle diameter of 1 μm, and then heated at 1450 ° C. for 30 minutes under reduced pressure. The temperature was returned to room temperature, and the lump was pulverized with a hammer mill to produce granulated powder having an average particle size of 120 μm (particle size distribution range: 20 to 220 μm). It was confirmed by elemental analysis that the granulated powder contained 0.5% by mass of silicon element.
造粒粉とバインダー(アクリル樹脂)とを混合した。該混合物から精研社製TAP-2R型成形機にて密度7.8g/cm3の成形体を作製した。この成形の際に0.29mmφのタングステン線(陽極リード線)を埋設し外側に8mm植立させた。
得られた成形体を真空焼成炉に入れ、徐々に温度を上げた。昇温途中にバインダーが除去された。温度1540℃にて30分間維持して焼結させた。その後、室温まで降温した。1.0mm×1.5mm×4.5mmの大きさで且つ質量が55mgの焼結体を複数個作製した。 The granulated powder and a binder (acrylic resin) were mixed. A molded body having a density of 7.8 g / cm 3 was produced from the mixture using a TAP-2R molding machine manufactured by Seken. During the molding, a 0.29 mmφ tungsten wire (anode lead wire) was embedded and 8 mm outside was planted.
The obtained molded body was put into a vacuum firing furnace and the temperature was gradually raised. The binder was removed during the temperature increase. Sintering was performed at a temperature of 1540 ° C. for 30 minutes. Thereafter, the temperature was lowered to room temperature. A plurality of sintered bodies having a size of 1.0 mm × 1.5 mm × 4.5 mm and a mass of 55 mg were produced.
得られた成形体を真空焼成炉に入れ、徐々に温度を上げた。昇温途中にバインダーが除去された。温度1540℃にて30分間維持して焼結させた。その後、室温まで降温した。1.0mm×1.5mm×4.5mmの大きさで且つ質量が55mgの焼結体を複数個作製した。 The granulated powder and a binder (acrylic resin) were mixed. A molded body having a density of 7.8 g / cm 3 was produced from the mixture using a TAP-2R molding machine manufactured by Seken. During the molding, a 0.29 mmφ tungsten wire (anode lead wire) was embedded and 8 mm outside was planted.
The obtained molded body was put into a vacuum firing furnace and the temperature was gradually raised. The binder was removed during the temperature increase. Sintering was performed at a temperature of 1540 ° C. for 30 minutes. Thereafter, the temperature was lowered to room temperature. A plurality of sintered bodies having a size of 1.0 mm × 1.5 mm × 4.5 mm and a mass of 55 mg were produced.
〔誘電体層の形成(化成処理)〕
0.1質量%硝酸水溶液を化成液として用意した。化成液をステンレス製容器に入れた。前記焼結体を、陽極リード線の一部を除いて、化成液に浸漬した。陽極リードを電源の陽極に、容器を電源の陰極にそれぞれ電気的に接続し、化成液の液温20℃で、初期電流密度36mA/gにて電圧印加を開始し、該電流密度値を維持し、10Vに達した時から電圧10Vに7時間維持した。次いで、純水で洗浄し、乾燥させた。 [Formation of dielectric layer (chemical conversion treatment)]
A 0.1% by mass nitric acid aqueous solution was prepared as a chemical conversion solution. The chemical conversion liquid was put into a stainless steel container. The sintered body was immersed in the chemical conversion liquid except for a part of the anode lead wire. The anode lead is electrically connected to the anode of the power source, and the container is electrically connected to the cathode of the power source, and the voltage application is started at an initial current density of 36 mA / g at a liquid temperature of 20 ° C., and the current density value is maintained. Then, the voltage was maintained at 10 V for 7 hours after reaching 10 V. Then, it was washed with pure water and dried.
0.1質量%硝酸水溶液を化成液として用意した。化成液をステンレス製容器に入れた。前記焼結体を、陽極リード線の一部を除いて、化成液に浸漬した。陽極リードを電源の陽極に、容器を電源の陰極にそれぞれ電気的に接続し、化成液の液温20℃で、初期電流密度36mA/gにて電圧印加を開始し、該電流密度値を維持し、10Vに達した時から電圧10Vに7時間維持した。次いで、純水で洗浄し、乾燥させた。 [Formation of dielectric layer (chemical conversion treatment)]
A 0.1% by mass nitric acid aqueous solution was prepared as a chemical conversion solution. The chemical conversion liquid was put into a stainless steel container. The sintered body was immersed in the chemical conversion liquid except for a part of the anode lead wire. The anode lead is electrically connected to the anode of the power source, and the container is electrically connected to the cathode of the power source, and the voltage application is started at an initial current density of 36 mA / g at a liquid temperature of 20 ° C., and the current density value is maintained. Then, the voltage was maintained at 10 V for 7 hours after reaching 10 V. Then, it was washed with pure water and dried.
日本電子株式会社製走査型電子顕微鏡JSM-7500FAにて誘電体層を観察した。図2および図3に示すように、陽極体は一つの粒状物と他の一つの粒状物とが相互に相貫して数珠状に繋がった形状を有し、粒状物の間に空間(細孔)がある形となっており、その表面には適切な厚みを持つ十分に緻密な誘電体層が形成されていた。誘電体層の厚さは、場所によって異なるが、概ね30~50nmの範囲内にあった。誘電体層の表面には分岐、交差またはループを成した襞状突起が在った。また誘電体層には図5に示すような平らな面(結晶面)を有する塊(結晶)が観察されなかった。元素分析によると、誘電体層はタングステンと酸素とを含むものであった。X線回折によると、タングステン酸化物の結晶由来の回折ピークは検出されなかった(図4参照)。
The dielectric layer was observed with a scanning electron microscope JSM-7500FA manufactured by JEOL Ltd. As shown in FIG. 2 and FIG. 3, the anode body has a shape in which one granular material and another granular material are interlaced with each other and connected in a bead shape. There was a hole), and a sufficiently dense dielectric layer having an appropriate thickness was formed on the surface. The thickness of the dielectric layer varies depending on the location, but is generally in the range of 30 to 50 nm. On the surface of the dielectric layer, there were ridge-like projections that were branched, crossed, or looped. In addition, a lump (crystal) having a flat surface (crystal surface) as shown in FIG. 5 was not observed in the dielectric layer. According to elemental analysis, the dielectric layer contained tungsten and oxygen. According to X-ray diffraction, no diffraction peak derived from the tungsten oxide crystal was detected (see FIG. 4).
〔半導電体層の積層〕
i)浸漬工程
誘電体層が形成された焼結体を、5質量%のエチレンジオキシチオフェン(以下EDTHと略す)エタノール溶液に浸漬した。該エタノール溶液から引き上げて室温にて乾燥させた。次いで、10質量%のトルエンスルフォン酸鉄水溶液に浸漬した。該水溶液から引き上げて60℃にて10分間保持し、反応させた。この一連の操作を5回繰り返して処理体を得た。 [Lamination of semiconductive layer]
i) Immersion step The sintered body on which the dielectric layer was formed was immersed in an ethanol solution of 5% by mass of ethylenedioxythiophene (hereinafter abbreviated as EDTH). The ethanol solution was pulled up and dried at room temperature. Subsequently, it was immersed in 10 mass% toluene iron sulfonate aqueous solution. The aqueous solution was pulled up and held at 60 ° C. for 10 minutes for reaction. This series of operations was repeated 5 times to obtain a treated body.
i)浸漬工程
誘電体層が形成された焼結体を、5質量%のエチレンジオキシチオフェン(以下EDTHと略す)エタノール溶液に浸漬した。該エタノール溶液から引き上げて室温にて乾燥させた。次いで、10質量%のトルエンスルフォン酸鉄水溶液に浸漬した。該水溶液から引き上げて60℃にて10分間保持し、反応させた。この一連の操作を5回繰り返して処理体を得た。 [Lamination of semiconductive layer]
i) Immersion step The sintered body on which the dielectric layer was formed was immersed in an ethanol solution of 5% by mass of ethylenedioxythiophene (hereinafter abbreviated as EDTH). The ethanol solution was pulled up and dried at room temperature. Subsequently, it was immersed in 10 mass% toluene iron sulfonate aqueous solution. The aqueous solution was pulled up and held at 60 ° C. for 10 minutes for reaction. This series of operations was repeated 5 times to obtain a treated body.
ii)電解重合工程
得られた処理体を20質量%EDTHエタノール溶液に浸漬した。該エタノール溶液から引き上げた。引き続き、ステンレス(SUS303)製容器に貯留された液温20℃の重合液に、所定位置まで浸漬し、10μAで60分間電解重合した。なお、重合液は、水70質量部とエチレングリコール30質量部とからなる溶剤にEDTH0.4質量%及びアントラキノンスルホン酸0.6質量%を溶解させたものである。電解重合完了後、重合液から引き上げ、純水による洗浄およびエタノールによる洗浄を行い、次いで乾燥させた。誘電体層の表面上に導電性高分子からなる半導電体層が積層された。 ii) Electrolytic polymerization step The obtained treated body was immersed in a 20% by mass EDTH ethanol solution. The ethanol solution was pulled up. Then, it immersed in the polymerization liquid with the liquid temperature of 20 degreeC stored by the stainless steel (SUS303) container to the predetermined position, and electropolymerized at 10 microampere for 60 minutes. The polymerization solution is obtained by dissolving EDTH 0.4% by mass and anthraquinonesulfonic acid 0.6% by mass in a solvent composed of 70 parts by mass of water and 30 parts by mass of ethylene glycol. After completion of the electropolymerization, the polymer solution was pulled up, washed with pure water and ethanol, and then dried. A semiconductive layer made of a conductive polymer was laminated on the surface of the dielectric layer.
得られた処理体を20質量%EDTHエタノール溶液に浸漬した。該エタノール溶液から引き上げた。引き続き、ステンレス(SUS303)製容器に貯留された液温20℃の重合液に、所定位置まで浸漬し、10μAで60分間電解重合した。なお、重合液は、水70質量部とエチレングリコール30質量部とからなる溶剤にEDTH0.4質量%及びアントラキノンスルホン酸0.6質量%を溶解させたものである。電解重合完了後、重合液から引き上げ、純水による洗浄およびエタノールによる洗浄を行い、次いで乾燥させた。誘電体層の表面上に導電性高分子からなる半導電体層が積層された。 ii) Electrolytic polymerization step The obtained treated body was immersed in a 20% by mass EDTH ethanol solution. The ethanol solution was pulled up. Then, it immersed in the polymerization liquid with the liquid temperature of 20 degreeC stored by the stainless steel (SUS303) container to the predetermined position, and electropolymerized at 10 microampere for 60 minutes. The polymerization solution is obtained by dissolving EDTH 0.4% by mass and anthraquinonesulfonic acid 0.6% by mass in a solvent composed of 70 parts by mass of water and 30 parts by mass of ethylene glycol. After completion of the electropolymerization, the polymer solution was pulled up, washed with pure water and ethanol, and then dried. A semiconductive layer made of a conductive polymer was laminated on the surface of the dielectric layer.
iii)後化成工程
0.1質量%硝酸水溶液を化成液とした。半導電体層が形成された処理体を、化成液に浸漬した。化成液の液温20℃で、初期電流密度1.8mA/gにて電圧印加を開始し、該電流密度値を維持し、6.5Vに達した時から6.5Vに維持し、15分間電圧印加を行った。化成液から引き上げ、純水による洗浄およびエタノールによる洗浄を行い、次いで乾燥させた。 iii) Post-chemical conversion step A 0.1 mass% nitric acid aqueous solution was used as a chemical conversion solution. The treatment body on which the semiconductive layer was formed was immersed in the chemical conversion liquid. Application of voltage was started at an initial current density of 1.8 mA / g at a liquid temperature of 20 ° C., and the current density value was maintained. After reaching 6.5 V, the voltage was maintained at 6.5 V for 15 minutes. A voltage was applied. It was pulled out from the chemical conversion liquid, washed with pure water and ethanol, and then dried.
0.1質量%硝酸水溶液を化成液とした。半導電体層が形成された処理体を、化成液に浸漬した。化成液の液温20℃で、初期電流密度1.8mA/gにて電圧印加を開始し、該電流密度値を維持し、6.5Vに達した時から6.5Vに維持し、15分間電圧印加を行った。化成液から引き上げ、純水による洗浄およびエタノールによる洗浄を行い、次いで乾燥させた。 iii) Post-chemical conversion step A 0.1 mass% nitric acid aqueous solution was used as a chemical conversion solution. The treatment body on which the semiconductive layer was formed was immersed in the chemical conversion liquid. Application of voltage was started at an initial current density of 1.8 mA / g at a liquid temperature of 20 ° C., and the current density value was maintained. After reaching 6.5 V, the voltage was maintained at 6.5 V for 15 minutes. A voltage was applied. It was pulled out from the chemical conversion liquid, washed with pure water and ethanol, and then dried.
その後、上述の浸漬工程-電解重合工程-後化成工程をさらに7回(合計8回)繰り返し行った。なお、電解重合時の電流値は、第2回目を20μA、第3回目を30μA、第4回目~第8回目を50μAにそれぞれ設定した。
Thereafter, the above-mentioned dipping step-electrolytic polymerization step-post-chemical conversion step was further repeated 7 times (8 times in total). The current value during the electropolymerization was set to 20 μA for the second time, 30 μA for the third time, and 50 μA for the fourth to eighth times.
〔導電体層の積層〕
半導電体層が形成された処理体の所定部分にカーボンペーストを塗布し乾燥させてカーボンペースト層を形成した。カーボンペースト層の上に銀ペーストを塗布し乾燥させて銀ペースト層を形成した。このようにして固体電解コンデンサ素子を複数個作製した。 [Lamination of conductor layer]
A carbon paste was applied to a predetermined portion of the treated body on which the semiconductive layer was formed and dried to form a carbon paste layer. A silver paste was applied on the carbon paste layer and dried to form a silver paste layer. In this way, a plurality of solid electrolytic capacitor elements were produced.
半導電体層が形成された処理体の所定部分にカーボンペーストを塗布し乾燥させてカーボンペースト層を形成した。カーボンペースト層の上に銀ペーストを塗布し乾燥させて銀ペースト層を形成した。このようにして固体電解コンデンサ素子を複数個作製した。 [Lamination of conductor layer]
A carbon paste was applied to a predetermined portion of the treated body on which the semiconductive layer was formed and dried to form a carbon paste layer. A silver paste was applied on the carbon paste layer and dried to form a silver paste layer. In this way, a plurality of solid electrolytic capacitor elements were produced.
実施例2
誘電体層の形成時における、初期電流密度を180mA/gに、電圧印加時間を5時間にそれぞれ変更した以外は実施例1と同じ手法で固体電解コンデンサ素子を作製した。走査型電子顕微鏡で誘電体層を観察した。図2および図3に示すような誘電体層が生成した。誘電体層の表面には分岐、交差またはループを成した襞状突起が在った。また誘電体層には図5に示すような平らな面(結晶面)を有する塊(結晶)が観察されなかった。元素分析によると、誘電体層はタングステンと酸素とを含むものであった。 Example 2
A solid electrolytic capacitor element was produced in the same manner as in Example 1 except that the initial current density at the time of forming the dielectric layer was changed to 180 mA / g and the voltage application time was changed to 5 hours. The dielectric layer was observed with a scanning electron microscope. A dielectric layer as shown in FIGS. 2 and 3 was produced. On the surface of the dielectric layer, there were ridge-like projections that were branched, crossed, or looped. In addition, a lump (crystal) having a flat surface (crystal surface) as shown in FIG. 5 was not observed in the dielectric layer. According to elemental analysis, the dielectric layer contained tungsten and oxygen.
誘電体層の形成時における、初期電流密度を180mA/gに、電圧印加時間を5時間にそれぞれ変更した以外は実施例1と同じ手法で固体電解コンデンサ素子を作製した。走査型電子顕微鏡で誘電体層を観察した。図2および図3に示すような誘電体層が生成した。誘電体層の表面には分岐、交差またはループを成した襞状突起が在った。また誘電体層には図5に示すような平らな面(結晶面)を有する塊(結晶)が観察されなかった。元素分析によると、誘電体層はタングステンと酸素とを含むものであった。 Example 2
A solid electrolytic capacitor element was produced in the same manner as in Example 1 except that the initial current density at the time of forming the dielectric layer was changed to 180 mA / g and the voltage application time was changed to 5 hours. The dielectric layer was observed with a scanning electron microscope. A dielectric layer as shown in FIGS. 2 and 3 was produced. On the surface of the dielectric layer, there were ridge-like projections that were branched, crossed, or looped. In addition, a lump (crystal) having a flat surface (crystal surface) as shown in FIG. 5 was not observed in the dielectric layer. According to elemental analysis, the dielectric layer contained tungsten and oxygen.
実施例3
誘電体層の形成時における、初期電流密度を90mA/gに、電圧印加時間を5時間にそれぞれ変更した以外は実施例1と同じ手法で固体電解コンデンサ素子を作製した。走査型電子顕微鏡で誘電体層を観察した。図2および図3に示すような誘電体層が生成した。誘電体層の表面には分岐、交差またはループを成した襞状突起が在った。また誘電体層には図5に示すような平らな面(結晶面)を有する塊(結晶)が観察されなかった。元素分析によると、誘電体層はタングステンと酸素とを含むものであった。 Example 3
A solid electrolytic capacitor element was produced in the same manner as in Example 1 except that the initial current density at the time of forming the dielectric layer was changed to 90 mA / g and the voltage application time was changed to 5 hours. The dielectric layer was observed with a scanning electron microscope. A dielectric layer as shown in FIGS. 2 and 3 was produced. On the surface of the dielectric layer, there were ridge-like projections that were branched, crossed, or looped. In addition, a lump (crystal) having a flat surface (crystal surface) as shown in FIG. 5 was not observed in the dielectric layer. According to elemental analysis, the dielectric layer contained tungsten and oxygen.
誘電体層の形成時における、初期電流密度を90mA/gに、電圧印加時間を5時間にそれぞれ変更した以外は実施例1と同じ手法で固体電解コンデンサ素子を作製した。走査型電子顕微鏡で誘電体層を観察した。図2および図3に示すような誘電体層が生成した。誘電体層の表面には分岐、交差またはループを成した襞状突起が在った。また誘電体層には図5に示すような平らな面(結晶面)を有する塊(結晶)が観察されなかった。元素分析によると、誘電体層はタングステンと酸素とを含むものであった。 Example 3
A solid electrolytic capacitor element was produced in the same manner as in Example 1 except that the initial current density at the time of forming the dielectric layer was changed to 90 mA / g and the voltage application time was changed to 5 hours. The dielectric layer was observed with a scanning electron microscope. A dielectric layer as shown in FIGS. 2 and 3 was produced. On the surface of the dielectric layer, there were ridge-like projections that were branched, crossed, or looped. In addition, a lump (crystal) having a flat surface (crystal surface) as shown in FIG. 5 was not observed in the dielectric layer. According to elemental analysis, the dielectric layer contained tungsten and oxygen.
実施例4
誘電体層の形成時における、初期電流密度を18mA/gに変更した以外は実施例1と同じ手法で固体電解コンデンサ素子を作製した。走査型電子顕微鏡で誘電体層を観察した。図2および図3に示すような誘電体層が生成した。誘電体層の表面には分岐、交差またはループを成した襞状突起が在った。また誘電体層には図5に示すような平らな面(結晶面)を有する塊(結晶)が観察されなかった。元素分析によると、誘電体層はタングステンと酸素とを含むものであった。 Example 4
A solid electrolytic capacitor element was produced in the same manner as in Example 1 except that the initial current density during the formation of the dielectric layer was changed to 18 mA / g. The dielectric layer was observed with a scanning electron microscope. A dielectric layer as shown in FIGS. 2 and 3 was produced. On the surface of the dielectric layer, there were ridge-like projections that were branched, crossed, or looped. In addition, a lump (crystal) having a flat surface (crystal surface) as shown in FIG. 5 was not observed in the dielectric layer. According to elemental analysis, the dielectric layer contained tungsten and oxygen.
誘電体層の形成時における、初期電流密度を18mA/gに変更した以外は実施例1と同じ手法で固体電解コンデンサ素子を作製した。走査型電子顕微鏡で誘電体層を観察した。図2および図3に示すような誘電体層が生成した。誘電体層の表面には分岐、交差またはループを成した襞状突起が在った。また誘電体層には図5に示すような平らな面(結晶面)を有する塊(結晶)が観察されなかった。元素分析によると、誘電体層はタングステンと酸素とを含むものであった。 Example 4
A solid electrolytic capacitor element was produced in the same manner as in Example 1 except that the initial current density during the formation of the dielectric layer was changed to 18 mA / g. The dielectric layer was observed with a scanning electron microscope. A dielectric layer as shown in FIGS. 2 and 3 was produced. On the surface of the dielectric layer, there were ridge-like projections that were branched, crossed, or looped. In addition, a lump (crystal) having a flat surface (crystal surface) as shown in FIG. 5 was not observed in the dielectric layer. According to elemental analysis, the dielectric layer contained tungsten and oxygen.
実施例5
誘電体層の形成時における、化成液の硝酸の濃度および温度を0.2質量%および10℃に変更し、初期電流密度を9mA/gに変更した以外は実施例1と同じ手法で固体電解コンデンサ素子を作製した。走査型電子顕微鏡で誘電体層を観察した。図2および図3に示すような誘電体層が生成した。誘電体層の表面には分岐、交差またはループを成した襞状突起が在った。また誘電体層には図5に示すような平らな面(結晶面)を有する塊(結晶)が観察されなかった。元素分析によると、誘電体層はタングステンと酸素とを含むものであった。 Example 5
Solid electrolysis was performed in the same manner as in Example 1 except that the concentration and temperature of nitric acid in the chemical conversion solution were changed to 0.2% by mass and 10 ° C., and the initial current density was changed to 9 mA / g. A capacitor element was produced. The dielectric layer was observed with a scanning electron microscope. A dielectric layer as shown in FIGS. 2 and 3 was produced. On the surface of the dielectric layer, there were ridge-like projections that were branched, crossed, or looped. In addition, a lump (crystal) having a flat surface (crystal surface) as shown in FIG. 5 was not observed in the dielectric layer. According to elemental analysis, the dielectric layer contained tungsten and oxygen.
誘電体層の形成時における、化成液の硝酸の濃度および温度を0.2質量%および10℃に変更し、初期電流密度を9mA/gに変更した以外は実施例1と同じ手法で固体電解コンデンサ素子を作製した。走査型電子顕微鏡で誘電体層を観察した。図2および図3に示すような誘電体層が生成した。誘電体層の表面には分岐、交差またはループを成した襞状突起が在った。また誘電体層には図5に示すような平らな面(結晶面)を有する塊(結晶)が観察されなかった。元素分析によると、誘電体層はタングステンと酸素とを含むものであった。 Example 5
Solid electrolysis was performed in the same manner as in Example 1 except that the concentration and temperature of nitric acid in the chemical conversion solution were changed to 0.2% by mass and 10 ° C., and the initial current density was changed to 9 mA / g. A capacitor element was produced. The dielectric layer was observed with a scanning electron microscope. A dielectric layer as shown in FIGS. 2 and 3 was produced. On the surface of the dielectric layer, there were ridge-like projections that were branched, crossed, or looped. In addition, a lump (crystal) having a flat surface (crystal surface) as shown in FIG. 5 was not observed in the dielectric layer. According to elemental analysis, the dielectric layer contained tungsten and oxygen.
実施例6
造粒粉を作製するときに珪素を添加しなかった以外は実施例1と同じ手法で固体電解コンデンサ素子を作製した。走査型電子顕微鏡で誘電体層を観察した。図2および図3に示すような誘電体層が生成した。誘電体層の表面には分岐、交差またはループを成した襞状突起が在った。また誘電体層には図5に示すような平らな面(結晶面)を有する塊(結晶)が観察されなかった。元素分析によると、誘電体層はタングステンと酸素とを含むものであった。 Example 6
A solid electrolytic capacitor element was produced in the same manner as in Example 1 except that silicon was not added when the granulated powder was produced. The dielectric layer was observed with a scanning electron microscope. A dielectric layer as shown in FIGS. 2 and 3 was produced. On the surface of the dielectric layer, there were ridge-like projections that were branched, crossed, or looped. In addition, a lump (crystal) having a flat surface (crystal surface) as shown in FIG. 5 was not observed in the dielectric layer. According to elemental analysis, the dielectric layer contained tungsten and oxygen.
造粒粉を作製するときに珪素を添加しなかった以外は実施例1と同じ手法で固体電解コンデンサ素子を作製した。走査型電子顕微鏡で誘電体層を観察した。図2および図3に示すような誘電体層が生成した。誘電体層の表面には分岐、交差またはループを成した襞状突起が在った。また誘電体層には図5に示すような平らな面(結晶面)を有する塊(結晶)が観察されなかった。元素分析によると、誘電体層はタングステンと酸素とを含むものであった。 Example 6
A solid electrolytic capacitor element was produced in the same manner as in Example 1 except that silicon was not added when the granulated powder was produced. The dielectric layer was observed with a scanning electron microscope. A dielectric layer as shown in FIGS. 2 and 3 was produced. On the surface of the dielectric layer, there were ridge-like projections that were branched, crossed, or looped. In addition, a lump (crystal) having a flat surface (crystal surface) as shown in FIG. 5 was not observed in the dielectric layer. According to elemental analysis, the dielectric layer contained tungsten and oxygen.
実施例7
造粒粉を作製するとき、原料となるタングステン粉に燐酸を0.2質量%加えた以外は実施例1と同じ手法で固体電解コンデンサ素子を作製した。なお、造粒粉には、珪素元素が0.5質量%、燐元素が270ppm含有されていることを元素分析により確認した。走査型電子顕微鏡で誘電体層を観察した。図2および図3に示すような誘電体層が生成した。誘電体層の表面には分岐、交差またはループを成した襞状突起が在った。また誘電体層には図5に示すような平らな面(結晶面)を有する塊(結晶)が観察されなかった。元素分析によると、誘電体層はタングステンと酸素とを含むものであった。 Example 7
When producing granulated powder, the solid electrolytic capacitor element was produced by the same method as Example 1 except having added 0.2 mass% of phosphoric acid to the tungsten powder used as a raw material. The granulated powder was confirmed by elemental analysis to contain 0.5% by mass of silicon element and 270 ppm of phosphorus element. The dielectric layer was observed with a scanning electron microscope. A dielectric layer as shown in FIGS. 2 and 3 was produced. On the surface of the dielectric layer, there were ridge-like projections that were branched, crossed, or looped. In addition, a lump (crystal) having a flat surface (crystal surface) as shown in FIG. 5 was not observed in the dielectric layer. According to elemental analysis, the dielectric layer contained tungsten and oxygen.
造粒粉を作製するとき、原料となるタングステン粉に燐酸を0.2質量%加えた以外は実施例1と同じ手法で固体電解コンデンサ素子を作製した。なお、造粒粉には、珪素元素が0.5質量%、燐元素が270ppm含有されていることを元素分析により確認した。走査型電子顕微鏡で誘電体層を観察した。図2および図3に示すような誘電体層が生成した。誘電体層の表面には分岐、交差またはループを成した襞状突起が在った。また誘電体層には図5に示すような平らな面(結晶面)を有する塊(結晶)が観察されなかった。元素分析によると、誘電体層はタングステンと酸素とを含むものであった。 Example 7
When producing granulated powder, the solid electrolytic capacitor element was produced by the same method as Example 1 except having added 0.2 mass% of phosphoric acid to the tungsten powder used as a raw material. The granulated powder was confirmed by elemental analysis to contain 0.5% by mass of silicon element and 270 ppm of phosphorus element. The dielectric layer was observed with a scanning electron microscope. A dielectric layer as shown in FIGS. 2 and 3 was produced. On the surface of the dielectric layer, there were ridge-like projections that were branched, crossed, or looped. In addition, a lump (crystal) having a flat surface (crystal surface) as shown in FIG. 5 was not observed in the dielectric layer. According to elemental analysis, the dielectric layer contained tungsten and oxygen.
実施例8
誘電体層の形成時における、硝酸水溶液の硝酸濃度および温度を0.2質量%および0℃に変更し、初期電流密度を55mA/gに変更し、電圧印加時間を10時間に変更した以外は実施例1と同じ手法で固体電解コンデンサ素子を作製した。走査型電子顕微鏡で誘電体層を観察した。図2および図3に示すような誘電体層が生成した。誘電体層の表面には分岐、交差またはループを成した襞状突起が在った。また誘電体層には図5に示すような平らな面(結晶面)を有する塊(結晶)が観察されなかった。元素分析によると、誘電体層はタングステンと酸素とを含むものであった。 Example 8
The nitric acid concentration and temperature of the aqueous nitric acid solution were changed to 0.2% by mass and 0 ° C., the initial current density was changed to 55 mA / g, and the voltage application time was changed to 10 hours when forming the dielectric layer. A solid electrolytic capacitor element was produced in the same manner as in Example 1. The dielectric layer was observed with a scanning electron microscope. A dielectric layer as shown in FIGS. 2 and 3 was produced. On the surface of the dielectric layer, there were ridge-like projections that were branched, crossed, or looped. In addition, a lump (crystal) having a flat surface (crystal surface) as shown in FIG. 5 was not observed in the dielectric layer. According to elemental analysis, the dielectric layer contained tungsten and oxygen.
誘電体層の形成時における、硝酸水溶液の硝酸濃度および温度を0.2質量%および0℃に変更し、初期電流密度を55mA/gに変更し、電圧印加時間を10時間に変更した以外は実施例1と同じ手法で固体電解コンデンサ素子を作製した。走査型電子顕微鏡で誘電体層を観察した。図2および図3に示すような誘電体層が生成した。誘電体層の表面には分岐、交差またはループを成した襞状突起が在った。また誘電体層には図5に示すような平らな面(結晶面)を有する塊(結晶)が観察されなかった。元素分析によると、誘電体層はタングステンと酸素とを含むものであった。 Example 8
The nitric acid concentration and temperature of the aqueous nitric acid solution were changed to 0.2% by mass and 0 ° C., the initial current density was changed to 55 mA / g, and the voltage application time was changed to 10 hours when forming the dielectric layer. A solid electrolytic capacitor element was produced in the same manner as in Example 1. The dielectric layer was observed with a scanning electron microscope. A dielectric layer as shown in FIGS. 2 and 3 was produced. On the surface of the dielectric layer, there were ridge-like projections that were branched, crossed, or looped. In addition, a lump (crystal) having a flat surface (crystal surface) as shown in FIG. 5 was not observed in the dielectric layer. According to elemental analysis, the dielectric layer contained tungsten and oxygen.
比較例1
誘電体層の形成時及び後化成時の化成液を0.1質量%燐酸水溶液に変更し、誘電体層形成時における化成液の液温を65℃に変更し、初期電流密度を1.8mA/gに変更した以外は実施例1と同じ手法で固体電解コンデンサ素子を作製した。走査型電子顕微鏡で誘電体層を観察した。誘電体層には図5に示すように平らな面(結晶面)を有する塊(結晶)が、走査型電子顕微鏡観察での100μm2の視野中に10個を超える数で観察された。 Comparative Example 1
The chemical solution at the time of dielectric layer formation and post-formation was changed to 0.1% by mass phosphoric acid aqueous solution, the temperature of the chemical solution at the time of dielectric layer formation was changed to 65 ° C., and the initial current density was 1.8 mA. A solid electrolytic capacitor element was produced in the same manner as in Example 1 except that the amount was changed to / g. The dielectric layer was observed with a scanning electron microscope. As shown in FIG. 5, in the dielectric layer, a lump (crystal) having a flat surface (crystal surface) was observed in a number of more than 10 in a field of 100 μm 2 observed with a scanning electron microscope.
誘電体層の形成時及び後化成時の化成液を0.1質量%燐酸水溶液に変更し、誘電体層形成時における化成液の液温を65℃に変更し、初期電流密度を1.8mA/gに変更した以外は実施例1と同じ手法で固体電解コンデンサ素子を作製した。走査型電子顕微鏡で誘電体層を観察した。誘電体層には図5に示すように平らな面(結晶面)を有する塊(結晶)が、走査型電子顕微鏡観察での100μm2の視野中に10個を超える数で観察された。 Comparative Example 1
The chemical solution at the time of dielectric layer formation and post-formation was changed to 0.1% by mass phosphoric acid aqueous solution, the temperature of the chemical solution at the time of dielectric layer formation was changed to 65 ° C., and the initial current density was 1.8 mA. A solid electrolytic capacitor element was produced in the same manner as in Example 1 except that the amount was changed to / g. The dielectric layer was observed with a scanning electron microscope. As shown in FIG. 5, in the dielectric layer, a lump (crystal) having a flat surface (crystal surface) was observed in a number of more than 10 in a field of 100 μm 2 observed with a scanning electron microscope.
比較例2
誘電体層の形成時及び後化成時の化成液を1.0質量%燐酸水溶液に変更し、誘電体層形成時における化成液の液温を25℃に変更した以外は実施例1と同じ手法で固体電解コンデンサ素子を作製した。走査型電子顕微鏡で誘電体層を観察した。誘電体層には図5と同様な平らな面(結晶面)を有する塊(結晶)が走査型電子顕微鏡観察での100μm2の視野中に10個を超える数で観察された。 Comparative Example 2
The same method as in Example 1 except that the formation solution at the time of forming the dielectric layer and the post-formation was changed to 1.0 mass% phosphoric acid aqueous solution, and the temperature of the formation solution at the time of forming the dielectric layer was changed to 25 ° C. A solid electrolytic capacitor element was produced. The dielectric layer was observed with a scanning electron microscope. In the dielectric layer, a lump (crystal) having a flat surface (crystal surface) similar to that in FIG. 5 was observed in a number of more than 10 in a 100 μm 2 field of view with a scanning electron microscope.
誘電体層の形成時及び後化成時の化成液を1.0質量%燐酸水溶液に変更し、誘電体層形成時における化成液の液温を25℃に変更した以外は実施例1と同じ手法で固体電解コンデンサ素子を作製した。走査型電子顕微鏡で誘電体層を観察した。誘電体層には図5と同様な平らな面(結晶面)を有する塊(結晶)が走査型電子顕微鏡観察での100μm2の視野中に10個を超える数で観察された。 Comparative Example 2
The same method as in Example 1 except that the formation solution at the time of forming the dielectric layer and the post-formation was changed to 1.0 mass% phosphoric acid aqueous solution, and the temperature of the formation solution at the time of forming the dielectric layer was changed to 25 ° C. A solid electrolytic capacitor element was produced. The dielectric layer was observed with a scanning electron microscope. In the dielectric layer, a lump (crystal) having a flat surface (crystal surface) similar to that in FIG. 5 was observed in a number of more than 10 in a 100 μm 2 field of view with a scanning electron microscope.
比較例3
誘電体層の形成時及び後化成時の化成液を2.0質量%硫酸水溶液に変更し、誘電体層形成時における化成液の液温を35℃に変更した以外は実施例1と同じ手法で固体電解コンデンサ素子を作製した。走査型電子顕微鏡で誘電体層を観察した。誘電体層には図5と同様な平らな面(結晶面)を有する塊(結晶)が走査型電子顕微鏡観察での100μm2の視野中に10個を超える数で観察された。 Comparative Example 3
The same method as in Example 1 except that the chemical solution at the time of dielectric layer formation and post-formation was changed to 2.0 mass% sulfuric acid aqueous solution, and the liquid temperature of the chemical solution at the time of dielectric layer formation was changed to 35 ° C. A solid electrolytic capacitor element was produced. The dielectric layer was observed with a scanning electron microscope. In the dielectric layer, a lump (crystal) having a flat surface (crystal surface) similar to that in FIG. 5 was observed in a number of more than 10 in a 100 μm 2 field of view with a scanning electron microscope.
誘電体層の形成時及び後化成時の化成液を2.0質量%硫酸水溶液に変更し、誘電体層形成時における化成液の液温を35℃に変更した以外は実施例1と同じ手法で固体電解コンデンサ素子を作製した。走査型電子顕微鏡で誘電体層を観察した。誘電体層には図5と同様な平らな面(結晶面)を有する塊(結晶)が走査型電子顕微鏡観察での100μm2の視野中に10個を超える数で観察された。 Comparative Example 3
The same method as in Example 1 except that the chemical solution at the time of dielectric layer formation and post-formation was changed to 2.0 mass% sulfuric acid aqueous solution, and the liquid temperature of the chemical solution at the time of dielectric layer formation was changed to 35 ° C. A solid electrolytic capacitor element was produced. The dielectric layer was observed with a scanning electron microscope. In the dielectric layer, a lump (crystal) having a flat surface (crystal surface) similar to that in FIG. 5 was observed in a number of more than 10 in a 100 μm 2 field of view with a scanning electron microscope.
比較例4
誘電体層形成時における化成液の温度を80℃に変更し、初期電流密度を3.6mA/gに変更した以外は実施例1と同じ手法で固体電解コンデンサ素子を作製した。走査型電子顕微鏡で誘電体層を観察した。誘電体層には図5と同様な平らな面(結晶面)を有する塊(結晶)が走査型電子顕微鏡観察での100μm2の視野中に10個を超える数で観察された。 Comparative Example 4
A solid electrolytic capacitor element was produced in the same manner as in Example 1 except that the temperature of the chemical conversion solution during the formation of the dielectric layer was changed to 80 ° C. and the initial current density was changed to 3.6 mA / g. The dielectric layer was observed with a scanning electron microscope. In the dielectric layer, a lump (crystal) having a flat surface (crystal surface) similar to that in FIG. 5 was observed in a number of more than 10 in a 100 μm 2 field of view with a scanning electron microscope.
誘電体層形成時における化成液の温度を80℃に変更し、初期電流密度を3.6mA/gに変更した以外は実施例1と同じ手法で固体電解コンデンサ素子を作製した。走査型電子顕微鏡で誘電体層を観察した。誘電体層には図5と同様な平らな面(結晶面)を有する塊(結晶)が走査型電子顕微鏡観察での100μm2の視野中に10個を超える数で観察された。 Comparative Example 4
A solid electrolytic capacitor element was produced in the same manner as in Example 1 except that the temperature of the chemical conversion solution during the formation of the dielectric layer was changed to 80 ° C. and the initial current density was changed to 3.6 mA / g. The dielectric layer was observed with a scanning electron microscope. In the dielectric layer, a lump (crystal) having a flat surface (crystal surface) similar to that in FIG. 5 was observed in a number of more than 10 in a 100 μm 2 field of view with a scanning electron microscope.
以上各例で作製した固体電解コンデンサ素子に室温下で2.5Vの電圧を30秒間印加し、その後、漏れ電流を測定した。その結果を表1に示す。なお、表1中の漏れ電流の値は、素子64個の測定値の平均である。
A voltage of 2.5 V was applied to the solid electrolytic capacitor element produced in each example at room temperature for 30 seconds, and then the leakage current was measured. The results are shown in Table 1. In addition, the value of the leakage current in Table 1 is an average of the measured values of 64 elements.
本発明に係るコンデンサ素子(実施例)は、漏れ電流が極めて少ないことがわかる。一方、従来の化成処理法で作製されたコンデンサ素子(比較例)は、漏れ電流が多いことがわかる。
It can be seen that the capacitor element (Example) according to the present invention has very little leakage current. On the other hand, it can be seen that the capacitor element (comparative example) manufactured by the conventional chemical conversion treatment method has a large leakage current.
1:陽極体(タングステン粉)
2:誘電体層(タングステン酸化物の層)
3:襞状突起
5、12:細孔
13:塊(結晶)
A:薄膜法によるX線回折ピーク
B:2θ/θ法によるX線回折ピーク 1: Anode body (tungsten powder)
2: Dielectric layer (tungsten oxide layer)
3: Sponge-like protrusions 5, 12: Pore 13: Lump (crystal)
A: X-ray diffraction peak by thin film method B: X-ray diffraction peak by 2θ / θ method
2:誘電体層(タングステン酸化物の層)
3:襞状突起
5、12:細孔
13:塊(結晶)
A:薄膜法によるX線回折ピーク
B:2θ/θ法によるX線回折ピーク 1: Anode body (tungsten powder)
2: Dielectric layer (tungsten oxide layer)
3: Sponge-
A: X-ray diffraction peak by thin film method B: X-ray diffraction peak by 2θ / θ method
Claims (9)
- タングステンを含有して成る陽極体と、陽極体表面に在り且つタングステン酸化物を含有して成る誘電体層とを少なくとも有し、
誘電体層は、走査型電子顕微鏡において結晶が実質的に観察されない、コンデンサ素子。 An anode body containing tungsten, and at least a dielectric layer on the surface of the anode body and containing tungsten oxide,
The dielectric layer is a capacitor element in which crystals are not substantially observed in a scanning electron microscope. - タングステンを含有して成る陽極体と、陽極体表面に在り且つ非晶質タングステン酸化物からなる誘電体層とを少なくとも有するコンデンサ素子。 A capacitor element having at least an anode body containing tungsten and a dielectric layer on the surface of the anode body and made of amorphous tungsten oxide.
- タングステンを含有して成る陽極体と、陽極体表面に在り且つタングステン酸化物を含有して成る誘電体層とを少なくとも有し、
誘電体層は、X線回折においてタングステン酸化物の結晶由来の回折ピークが観測されない、コンデンサ素子。 An anode body containing tungsten, and at least a dielectric layer on the surface of the anode body and containing tungsten oxide,
The dielectric layer is a capacitor element in which a diffraction peak derived from a tungsten oxide crystal is not observed in X-ray diffraction. - 誘電体層はその表面に複数の突起を有する、請求項1~3のいずれかひとつに記載のコンデンサ素子。 The capacitor element according to any one of claims 1 to 3, wherein the dielectric layer has a plurality of protrusions on a surface thereof.
- 突起の高さが誘電体層の厚さの0.1倍以上3倍未満である、請求項4に記載のコンデンサ素子。 5. The capacitor element according to claim 4, wherein the height of the protrusion is not less than 0.1 times and less than 3 times the thickness of the dielectric layer.
- 誘電体層はその表面に高さに対する半値全幅の比が1以下である突起を少なくとも有する、請求項1~3のいずれかひとつに記載のコンデンサ素子。 The capacitor element according to any one of claims 1 to 3, wherein the dielectric layer has at least a protrusion having a ratio of a full width at half maximum to a height of 1 or less on a surface thereof.
- タングステンを含有して成る陽極体がタングステン焼結体である、請求項1~6のいずれかひとつに記載のコンデンサ素子。 7. The capacitor element according to claim 1, wherein the anode body containing tungsten is a tungsten sintered body.
- 請求項1~7のいずれかひとつに記載のコンデンサ素子を含有するコンデンサ。 A capacitor containing the capacitor element according to any one of claims 1 to 7.
- 硝酸0.05~0.5質量%を含む液温30℃以下の水溶液中で、タングステン粉の焼結体に、初期電流密度9~300mA/gにて3~11時間電圧印加して、該焼結体表面層を誘電体に化成することを含む、請求項1~7のいずれかひとつに記載のコンデンサ素子の製造方法。 In an aqueous solution containing nitric acid 0.05 to 0.5 mass% and having a liquid temperature of 30 ° C. or lower, a voltage was applied to the sintered tungsten powder at an initial current density of 9 to 300 mA / g for 3 to 11 hours. The method of manufacturing a capacitor element according to any one of claims 1 to 7, comprising forming the sintered body surface layer into a dielectric.
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JP2014053387A (en) * | 2012-09-05 | 2014-03-20 | Nippon Chemicon Corp | Manufacturing method of solid electrolytic capacitor |
JP5824115B1 (en) * | 2014-06-23 | 2015-11-25 | 昭和電工株式会社 | Method for manufacturing tungsten-based capacitor element |
JP5840821B1 (en) * | 2014-09-11 | 2016-01-06 | 昭和電工株式会社 | Tungsten capacitor element and manufacturing method thereof |
WO2016038959A1 (en) * | 2014-09-11 | 2016-03-17 | 昭和電工株式会社 | Tungsten capacitor element and method for manufacturing same |
US20180137989A1 (en) * | 2016-11-14 | 2018-05-17 | Avx Corporation | Wet Electrolytic Capacitor for an Implantable Medical Device |
US10431389B2 (en) | 2016-11-14 | 2019-10-01 | Avx Corporation | Solid electrolytic capacitor for high voltage environments |
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JP2014053387A (en) * | 2012-09-05 | 2014-03-20 | Nippon Chemicon Corp | Manufacturing method of solid electrolytic capacitor |
JP5824115B1 (en) * | 2014-06-23 | 2015-11-25 | 昭和電工株式会社 | Method for manufacturing tungsten-based capacitor element |
JP5840821B1 (en) * | 2014-09-11 | 2016-01-06 | 昭和電工株式会社 | Tungsten capacitor element and manufacturing method thereof |
WO2016038959A1 (en) * | 2014-09-11 | 2016-03-17 | 昭和電工株式会社 | Tungsten capacitor element and method for manufacturing same |
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WO2018089961A1 (en) | 2016-11-14 | 2018-05-17 | Avx Corporation | Wet electrolytic capacitor for an implantable medical device |
US10431389B2 (en) | 2016-11-14 | 2019-10-01 | Avx Corporation | Solid electrolytic capacitor for high voltage environments |
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US10957493B2 (en) | 2017-12-05 | 2021-03-23 | Avx Corporation | Wet electrolytic capacitor for an implantable medical device |
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