JP2000232038A - Aluminum foil for electrolytic capacitor - Google Patents
Aluminum foil for electrolytic capacitorInfo
- Publication number
- JP2000232038A JP2000232038A JP3415799A JP3415799A JP2000232038A JP 2000232038 A JP2000232038 A JP 2000232038A JP 3415799 A JP3415799 A JP 3415799A JP 3415799 A JP3415799 A JP 3415799A JP 2000232038 A JP2000232038 A JP 2000232038A
- Authority
- JP
- Japan
- Prior art keywords
- foil
- oxide film
- aluminum foil
- etching
- electrolytic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000011888 foil Substances 0.000 title claims abstract description 143
- 229910052782 aluminium Inorganic materials 0.000 title claims abstract description 34
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 title claims abstract description 33
- 239000003990 capacitor Substances 0.000 title claims abstract description 30
- 238000000866 electrolytic etching Methods 0.000 claims abstract description 65
- 238000005033 Fourier transform infrared spectroscopy Methods 0.000 claims abstract description 9
- 238000005530 etching Methods 0.000 claims description 37
- 238000000137 annealing Methods 0.000 claims description 31
- 238000000034 method Methods 0.000 claims description 17
- 239000012535 impurity Substances 0.000 claims description 9
- 238000005097 cold rolling Methods 0.000 claims description 7
- 238000004833 X-ray photoelectron spectroscopy Methods 0.000 abstract description 7
- 238000000862 absorption spectrum Methods 0.000 abstract description 5
- 239000011248 coating agent Substances 0.000 abstract 7
- 238000000576 coating method Methods 0.000 abstract 7
- 239000010408 film Substances 0.000 description 82
- 239000000463 material Substances 0.000 description 22
- 238000012360 testing method Methods 0.000 description 18
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 10
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 9
- 238000004519 manufacturing process Methods 0.000 description 9
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 238000004458 analytical method Methods 0.000 description 6
- 239000007864 aqueous solution Substances 0.000 description 6
- 238000005452 bending Methods 0.000 description 5
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 5
- 239000004327 boric acid Substances 0.000 description 5
- 238000010571 fourier transform-infrared absorption spectrum Methods 0.000 description 5
- 239000000243 solution Substances 0.000 description 5
- 238000003860 storage Methods 0.000 description 5
- 229910018516 Al—O Inorganic materials 0.000 description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- WNLRTRBMVRJNCN-UHFFFAOYSA-N adipic acid Chemical compound OC(=O)CCCCC(O)=O WNLRTRBMVRJNCN-UHFFFAOYSA-N 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 238000005498 polishing Methods 0.000 description 4
- 238000005096 rolling process Methods 0.000 description 4
- 239000001488 sodium phosphate Substances 0.000 description 4
- 229910000162 sodium phosphate Inorganic materials 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- RYFMWSXOAZQYPI-UHFFFAOYSA-K trisodium phosphate Chemical compound [Na+].[Na+].[Na+].[O-]P([O-])([O-])=O RYFMWSXOAZQYPI-UHFFFAOYSA-K 0.000 description 4
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- 239000000460 chlorine Substances 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 235000006408 oxalic acid Nutrition 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 239000002344 surface layer Substances 0.000 description 3
- 230000004580 weight loss Effects 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 229910019142 PO4 Inorganic materials 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 239000001361 adipic acid Substances 0.000 description 2
- 235000011037 adipic acid Nutrition 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 238000007743 anodising Methods 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 2
- 229910021538 borax Inorganic materials 0.000 description 2
- 102220411551 c.74G>T Human genes 0.000 description 2
- 229910052801 chlorine Inorganic materials 0.000 description 2
- -1 chlorine ions Chemical class 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 239000008151 electrolyte solution Substances 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 239000010410 layer Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000009828 non-uniform distribution Methods 0.000 description 2
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 2
- 239000010452 phosphate Substances 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 102220253765 rs141230910 Human genes 0.000 description 2
- 238000002791 soaking Methods 0.000 description 2
- 235000011121 sodium hydroxide Nutrition 0.000 description 2
- 239000004328 sodium tetraborate Substances 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- FLDCSPABIQBYKP-UHFFFAOYSA-N 5-chloro-1,2-dimethylbenzimidazole Chemical compound ClC1=CC=C2N(C)C(C)=NC2=C1 FLDCSPABIQBYKP-UHFFFAOYSA-N 0.000 description 1
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- 239000001741 Ammonium adipate Substances 0.000 description 1
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- OTRAYOBSWCVTIN-UHFFFAOYSA-N OB(O)O.OB(O)O.OB(O)O.OB(O)O.OB(O)O.N.N.N.N.N.N.N.N.N.N.N.N.N.N.N Chemical compound OB(O)O.OB(O)O.OB(O)O.OB(O)O.OB(O)O.N.N.N.N.N.N.N.N.N.N.N.N.N.N.N OTRAYOBSWCVTIN-UHFFFAOYSA-N 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 235000019293 ammonium adipate Nutrition 0.000 description 1
- LFVGISIMTYGQHF-UHFFFAOYSA-N ammonium dihydrogen phosphate Chemical compound [NH4+].OP(O)([O-])=O LFVGISIMTYGQHF-UHFFFAOYSA-N 0.000 description 1
- 239000010407 anodic oxide Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- KRVSOGSZCMJSLX-UHFFFAOYSA-L chromic acid Substances O[Cr](O)(=O)=O KRVSOGSZCMJSLX-UHFFFAOYSA-L 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- MNNHAPBLZZVQHP-UHFFFAOYSA-N diammonium hydrogen phosphate Chemical compound [NH4+].[NH4+].OP([O-])([O-])=O MNNHAPBLZZVQHP-UHFFFAOYSA-N 0.000 description 1
- 229910000388 diammonium phosphate Inorganic materials 0.000 description 1
- 235000019838 diammonium phosphate Nutrition 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- AWJWCTOOIBYHON-UHFFFAOYSA-N furo[3,4-b]pyrazine-5,7-dione Chemical compound C1=CN=C2C(=O)OC(=O)C2=N1 AWJWCTOOIBYHON-UHFFFAOYSA-N 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 239000003112 inhibitor Substances 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 125000002467 phosphate group Chemical group [H]OP(=O)(O[H])O[*] 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000010926 purge Methods 0.000 description 1
- 238000001028 reflection method Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000001878 scanning electron micrograph Methods 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 238000009751 slip forming Methods 0.000 description 1
- 235000010339 sodium tetraborate Nutrition 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- WYXIGTJNYDDFFH-UHFFFAOYSA-Q triazanium;borate Chemical compound [NH4+].[NH4+].[NH4+].[O-]B([O-])[O-] WYXIGTJNYDDFFH-UHFFFAOYSA-Q 0.000 description 1
Landscapes
- ing And Chemical Polishing (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、電解コンデンサ用
アルミニウム箔に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum foil for an electrolytic capacitor.
【０００２】[0002]
【従来の技術】アルミニウムは、電気化学的にエッチン
グすることにより表面積を拡大でき、また、陽極酸化に
より表面に耐電圧性の酸化皮膜が形成され、誘電体とし
て利用でき、電解コンデンサの電極箔として利用した場
合に、比較的大きな静電容量を得ることができる。した
がって、アルミニウム電解コンデンサは、他のコンデン
サに比べて、小型で大容量で、しかも安価に製造でき、
エレクトロニクス機器などの電子回路に不可欠な電子部
品として、広く汎用されている。2. Description of the Related Art Aluminum can be increased in surface area by electrochemical etching, and a voltage-resistant oxide film is formed on the surface by anodic oxidation, which can be used as a dielectric and used as an electrode foil of an electrolytic capacitor. When used, a relatively large capacitance can be obtained. Therefore, aluminum electrolytic capacitors are smaller, have a larger capacity, and can be manufactured at lower cost than other capacitors.
It is widely used as an essential electronic component in electronic circuits such as electronic equipment.
【０００３】アルミニウム電解コンデンサは、例えば
「アルミニウム」( 第2 巻, 第4 号,1995 、130 〜140
頁) の「アルミニウム電解コンデンサ用電極箔の技術動
向」等に開示されているように、リード線を各々配した
陽極アルミニウム箔と陰極アルミニウム箔の両極２枚の
アルミニウム箔の間にセパレート紙を挟み、セパレート
紙に電解液を含浸させ、円柱状に巻いた後、パッケージ
内に封入した構造となっている。[0003] Aluminum electrolytic capacitors are known, for example, from "Aluminum" (Vol. 2, No. 4, 1995, 130-140).
Page), the electrode foil for aluminum electrolytic capacitors, etc., a separate paper is sandwiched between the two aluminum foils, the anode aluminum foil and the cathode aluminum foil, each of which is provided with a lead wire. Then, the separator paper is impregnated with an electrolytic solution, wound in a cylindrical shape, and then sealed in a package.
【０００４】通常、このアルミニウム箔乃至アルミニウ
ム合金箔（以下単にアルミニウムをAlと言う）素材に
は、陽極用にはAl純度が99.96%以上、あるいは99.9% 以
上、また、陰極用にはAl純度が99% 以上、あるいは99.8
% 以上の、各々高純度Alが使用される。[0004] Usually, the aluminum foil or aluminum alloy foil (hereinafter, aluminum is simply referred to as Al) material has an Al purity of 99.96% or more or 99.9% or more for an anode and an Al purity of 99.9% or more for a cathode. 99% or more, or 99.8
% Or more of high-purity Al is used.
【０００５】このような構成からなるAl電解コンデンサ
の静電容量（Ｃ）は、主としてAl箔（特に陽極Al箔）の
表面積と、陽極Al箔の表面（エッチングピット）に設け
る誘電体酸化皮膜（バリヤー型酸化皮膜）の厚さによっ
て決定され、具体的には次式、Ｃ＝8.855 ×10-8εＳ／
ｄ（μＦ）〔但し、ε：誘電率（８〜９）、Ｓ：誘電体
の表面積（ｃｍ2 ）、ｄ：誘電体の厚み（ｃｍ）〕で表
される。The capacitance (C) of the Al electrolytic capacitor having such a configuration mainly depends on the surface area of the Al foil (especially the anode Al foil) and the dielectric oxide film (the etching pit) provided on the surface (etching pit) of the anode Al foil. Is determined by the thickness of the barrier type oxide film), and specifically, the following formula: C = 8.855 × 10 −8 εS /
d (μF) [where, ε: dielectric constant (8 to 9), S: surface area of dielectric (cm 2 ), d: thickness of dielectric (cm)].
【０００６】したがって、Al電解コンデンサの静電容量
を大きくするためには、Al箔の表面積を拡大して、誘電
体の表面積を大きくすることが重要となる。このAl箔の
表面積の拡大は、素材Al箔コイル（厚さ0.02〜0.11mm、
幅500mm 程度) を、塩酸などの塩素イオン含有の電解液
中に浸漬するとともに、交流や直流電流を付与し、連続
的に電解エッチングすることによって行われる。そし
て、この電解エッチングにより、Al箔の表面に微細な凹
部乃至粗面状のピット層（以下エッチングピットと言
う）が連続的に形成され、この結果、Al箔の表面の実効
面積が拡大し、電極箔としての高い静電容量を確保す
る。Therefore, in order to increase the capacitance of the Al electrolytic capacitor, it is important to increase the surface area of the Al foil and increase the surface area of the dielectric. The expansion of the surface area of this Al foil is based on the material Al foil coil (0.02-0.11mm thick,
(With a width of about 500 mm) in an electrolytic solution containing chlorine ions such as hydrochloric acid, while applying an alternating current or a direct current to continuously perform electrolytic etching. Then, by this electrolytic etching, fine concave or rough pit layers (hereinafter referred to as etching pits) are continuously formed on the surface of the Al foil, and as a result, the effective area of the surface of the Al foil is increased, Secure high capacitance as electrode foil.
【０００７】また陽極用のAl電極箔の場合、Al箔の表面
には、誘電体層であるバリヤー型酸化皮膜が必要とな
り、このバリヤー型酸化皮膜の形成は、前記電解エッチ
ング工程に続く、化成（陽極酸化）処理工程によって、
同じく連続的に行われる。In the case of an Al electrode foil for an anode, a barrier-type oxide film as a dielectric layer is required on the surface of the Al foil, and the formation of the barrier-type oxide film is performed following the above-described electrolytic etching step. (Anodic oxidation)
It is also performed continuously.
【０００８】このように、電解エッチング工程は、Al箔
の表面積を拡大（Al箔の表面を粗面化）し、実効面積を
拡大して、単位面積当たりの高い静電容量を確保し、電
解コンデンサの小型化、高容量化を可能とする上で、非
常に重要な工程になっている。As described above, in the electrolytic etching step, the surface area of the Al foil is increased (the surface of the Al foil is roughened), the effective area is increased, and a high capacitance per unit area is secured. This is a very important step in enabling the miniaturization and high capacity of the capacitor.
【０００９】この電解エッチング工程において、特に軟
質箔の分野で問題となる点は、エッチングによるAl箔の
減量が過度になり、減量の増加割合に対する静電容量の
向上が乏しく、その結果単位面積当たりの静電容量の増
加が低くなる点と、エッチングピットの初期の発生が不
均一でまばらとなり、Al箔表面の溶け残りが多くなり、
エッチングムラが生じ、箔の静電容量の増加量が少な
く、かつ箔の強度が低下する点である。したがって、従
来から、電解エッチング工程において、エッチングに
よるAl箔の減量が必要以上に大きくならず、且つ高い静
電容量が達成できること、およびAl箔の強度を低下さ
せないことが重要な技術的課題となっている。In this electrolytic etching step, a problem that is particularly problematic in the field of soft foil is that the weight loss of the Al foil due to the etching becomes excessive, and the improvement of the capacitance with respect to the increase rate of the weight loss is poor. And the initial occurrence of etching pits is uneven and sparse, leaving more undissolved Al foil surface,
Etching unevenness occurs, the amount of increase in the capacitance of the foil is small, and the strength of the foil is reduced. Therefore, conventionally, in the electrolytic etching process, it has become an important technical problem that the weight loss of the Al foil due to etching does not become unnecessarily large, and that a high capacitance can be achieved and that the strength of the Al foil is not reduced. ing.
【００１０】従来から、この技術的課題達成のために、
種々の技術が提案されている。まず、Al電極箔の素材で
ある、Al箔の化学成分組成や組織の面からは、99.99 ％
の高純度Alをベースとし、Fe、Si、Cu等の特定の不純物
量を規制することが、特開昭62−8492号、特開昭62−18
1416号、特開平 −33176 号、特開平1 −38865 号、特
開平2 −51212 号、特開平4 −247855号、特開平4 −12
4806号、特開平5 −5145号等の各公報に開示されてい
る。これらは基本的に、前記不純物による粗大な析出物
がAl箔表面に存在していると、電解エッチングを施した
際に粗大孔が生じるという問題を解消したものである。Conventionally, in order to achieve this technical problem,
Various techniques have been proposed. First, in terms of the chemical composition and structure of the Al foil, which is the material of the Al electrode foil, 99.99%
Based on high-purity Al, it is possible to regulate the amount of specific impurities such as Fe, Si, Cu and the like, JP-A-62-8492, JP-A-62-18
No. 1416, JP-A-33176, JP-A-1-38865, JP-A-2-51212, JP-A-4-247855, JP-A-4-12
No. 4806 and Japanese Patent Laid-Open No. 5-5145. These are basically solutions to the problem that when coarse precipitates due to the impurities are present on the surface of the Al foil, coarse holes are generated when electrolytic etching is performed.
【００１１】また、Al箔の熱処理や製造条件の面から
は、99.99 ％の高純度Alをベースとし、均熱条件や焼鈍
条件を特定して、不純物による粗大な析出物が箔表面に
存在するのを防止する方法が、特開平2 −200749号、特
開平4 −176847号、特開平4 −311550号等の各公報で開
示されている。Further, from the viewpoint of heat treatment and manufacturing conditions of the Al foil, based on high-purity 99.99% Al, the soaking conditions and annealing conditions are specified, and coarse precipitates due to impurities are present on the foil surface. A method for preventing this is disclosed in JP-A-2-200749, JP-A-4-176847, JP-A-4-311550, and the like.
【００１２】更に、電解エッチングの処理条件の面から
の改善技術も種々提案されている。例えば、電解液にし
ゅう酸をエッチング抑制剤として添加するとともに、塩
酸等の電解液濃度を高くして、エッチング時間を短くし
て、エッチングピットの粗大化を防止する（ピット径を
小さくする）とともに、深いエッチングピットを得るこ
とが、特開平7 −161586号公報に開示されている。ま
た、静電容量の向上のために、硫酸、燐酸、シュウ酸、
ほう酸、クロム酸等の多孔質型陽極酸化皮膜生成能力を
持つ酸を含有する水溶液を用いて陽極酸化を行った後に
電解エッチングを行うことでエッチングピットの制御を
行い、エッチングピットの粗大化を防止する（ピット径
を小さくする）とともに、深いエッチングピットを得る
技術が特開昭55−127013号公報に開示されている。Furthermore, various techniques for improving the processing conditions of electrolytic etching have been proposed. For example, while adding oxalic acid to the electrolyte as an etching inhibitor, increasing the concentration of the electrolyte such as hydrochloric acid, shortening the etching time, and preventing the etching pits from becoming coarse (decreasing the pit diameter). Obtaining a deep etching pit is disclosed in JP-A-7-161586. In addition, sulfuric acid, phosphoric acid, oxalic acid,
Anodizing is performed using an aqueous solution containing an acid capable of forming a porous type anodic oxide film such as boric acid and chromic acid, and then electrolytic etching is performed to control etching pits and prevent coarsening of etching pits Japanese Patent Application Laid-Open No. 55-127003 discloses a technique for obtaining a deep etching pit while reducing the pit diameter.
【００１３】この点、前記従来技術のうち、まず、素材
面からの、Al箔の化学成分組成や組織あるいは製造条件
の改良は、箔材料中の不純物の析出による電解エッチン
グ時の粗大孔の防止などに、それなりの効果は認められ
るものの、Al箔の静電容量を増加させる点ではまだまだ
不十分である。そして、この点は、前記電解エッチング
処理条件の面からの改善技術も同様である。In this respect, among the above-mentioned prior arts, first, the improvement of the chemical composition, the structure, or the manufacturing conditions of the Al foil from the material side is to prevent coarse holes during electrolytic etching due to precipitation of impurities in the foil material. For example, although a certain effect is recognized, it is still insufficient to increase the capacitance of the Al foil. This also applies to the technology for improving the electrolytic etching conditions.
【００１４】一方、高い静電容量のAl箔を得ようとする
と、Al箔材料表面を均質にして、電解エッチングでのエ
ッチングムラの発生を防止する (以下電解エッチング性
と言う) ことが重要となってくる。そして、特に軟質箔
においては、焼鈍により軟質化されるため、Al箔材料表
面の均質性は、電解エッチングされる前の、特に前記焼
鈍によりAl箔表面に生成している酸化皮膜の均質性に大
きく依存している。その結果、Al箔表面の酸化皮膜の均
質性は、前記電解エッチング性に大きく影響する。On the other hand, in order to obtain an Al foil having a high capacitance, it is important to make the surface of the Al foil material uniform and to prevent the occurrence of etching unevenness in electrolytic etching (hereinafter referred to as electrolytic etching property). It is becoming. And, in particular, in the case of a soft foil, since it is softened by annealing, the homogeneity of the Al foil material surface depends on the homogeneity of the oxide film generated on the Al foil surface by electrolytic annealing, particularly before the electrolytic etching. Depends heavily. As a result, the homogeneity of the oxide film on the surface of the Al foil greatly affects the electrolytic etching property.
【００１５】このため、特公平7 −113155号公報のよう
に、Al箔を圧延後、Alに対し吸着性の高い酸または化合
物を含有する水溶液に接触させ、圧延後のAl箔を焼鈍
後、長時間放置しても、保管雰囲気中の水分や酸素と反
応して箔表面層が変質することを抑制することが開示さ
れている。また、特公平6 −188155号公報には、Al箔を
圧延および焼鈍後、焼鈍により生成しているAl箔コイル
の表面層( 主として酸化皮膜) を除去し、更に電解エッ
チング性の良い、コイルの幅方向に膜厚の一定な酸化皮
膜を形成することが開示されている。For this reason, as disclosed in Japanese Patent Publication No. 7-113155, after rolling an Al foil, it is brought into contact with an aqueous solution containing an acid or a compound having high adsorptivity to Al, and after rolling the Al foil, It is disclosed that even when the foil surface layer is left for a long time, the foil surface layer is prevented from reacting with moisture or oxygen in the storage atmosphere to be deteriorated. Further, Japanese Patent Publication No. Hei 6-188155 discloses that after rolling and annealing an Al foil, the surface layer (mainly an oxide film) of the Al foil coil generated by annealing is removed, and the coil has a good electrolytic etching property. It is disclosed that an oxide film having a constant thickness is formed in the width direction.
【００１６】しかしながら、これら従来技術において
も、酸化皮膜形成工程での雰囲気管理や、工程間のリー
ドタイムの管理が十分でなければ、コイルの幅方向で、
電解エッチングムラが生じ、静電容量を高くできず、電
解エッチング性改善の決め手にならない。However, even in these prior arts, if the atmosphere management in the oxide film forming step and the management of the lead time between the steps are not sufficient, the width of the coil cannot be increased in the width direction of the coil.
Electrolytic etching unevenness occurs, the capacitance cannot be increased, and it is not decisive for improving the electrolytic etching property.
【００１７】これに対し、本出願人は、先に特願平9-16
7440号において、酸化皮膜の均質性とは、単にAl箔表面
の酸化皮膜の膜厚だけで決まるものではなく、酸化皮膜
の緻密さで代表される膜質によっても決定されることを
知見した。即ち、Al箔の電解エッチング性は、電解エッ
チング前のAl箔表面の酸化皮膜 (酸化Al）の均質性によ
って支配され、例えば、Al箔表面の酸化皮膜の膜厚にば
らつきがある場合でも、膜厚の大きな酸化皮膜の部分が
比較的緻密ではなく、膜厚の小さな酸化皮膜の部分が比
較的緻密であった場合には、電解エッチング性が改善さ
れ、高い静電容量が確保される。On the other hand, the present applicant has previously filed Japanese Patent Application No.
No. 7440 found that the homogeneity of the oxide film was determined not only by the thickness of the oxide film on the surface of the Al foil, but also by the film quality represented by the denseness of the oxide film. That is, the electrolytic etching property of the Al foil is governed by the homogeneity of the oxide film (Al oxide) on the surface of the Al foil before the electrolytic etching. When the portion of the oxide film having a large thickness is not relatively dense and the portion of the oxide film having a small thickness is relatively dense, the electrolytic etching property is improved and a high capacitance is secured.
【００１８】そして、この知見に基づき、前記特願平9-
167440号では、Al箔の電解エッチング性＝Al箔表面の酸
化皮膜の均質性を正確に評価するためには、単に酸化皮
膜の膜厚からだけではなく、Al箔表面の酸化皮膜の膜厚
と膜質（緻密さ）の両方から評価する必要があるとし
た。そして、酸化皮膜の膜厚と膜質との積が、酸化皮膜
の均質性と非常に良く相関していること、また、酸化皮
膜の膜厚と膜質との積は、X= (I −900)5 ×D の式で示
される酸化皮膜指数X 〔但し、I:酸化皮膜のフーリエ変
換赤外吸収スペクトルにおいてAl−O の最も強い伸縮振
動に起因する反射ピークの波数(cm -1) 、D:酸化皮膜の
膜厚 (Å) を表す〕で示すことができることも知見し
た。Then, based on this finding, the above-mentioned Japanese Patent Application No.
In 167440, in order to accurately evaluate the homogeneity of the oxide film on the surface of Al foil, it is not only based on the thickness of the oxide film but also on the thickness of the oxide film on the surface of Al foil. It is necessary to evaluate both from the film quality (density). And the product of the oxide film thickness and film quality correlates very well with the homogeneity of the oxide film, and the product of the oxide film thickness and film quality is X = (I-900) The oxide film index X represented by the formula of 5 × D (where, I: the wave number (cm -1 ) of the reflection peak due to the strongest stretching vibration of Al-O in the Fourier transform infrared absorption spectrum of the oxide film, D: It represents the thickness (Å) of the oxide film].
【００１９】即ち、この反射ピークの波数 (反射ピーク
位置) と酸化皮膜の緻密さには一定の相関があり、反射
ピークの波数が多いほど (反射ピーク位置が高いほど)
、酸化皮膜が緻密であり、電解コンデンサ用Al箔上に
形成された薄膜の酸化皮膜の欠陥が少なく緻密であると
している。この結果、前記式の通り、このフーリエ変換
赤外吸収スペクトルにおいてAl−O の最も強い伸縮振動
に起因する反射ピークの波数Ｉを測定することで、酸化
皮膜の膜質を評価することを可能としている。That is, there is a certain correlation between the wave number of the reflection peak (reflection peak position) and the density of the oxide film, and the higher the reflection wave number (the higher the reflection peak position).
The oxide film is dense and the oxide film of the thin film formed on the Al foil for an electrolytic capacitor has few defects and is dense. As a result, as described above, in this Fourier transform infrared absorption spectrum, it is possible to evaluate the film quality of the oxide film by measuring the wave number I of the reflection peak caused by the strongest stretching vibration of Al-O. .
【００２０】そして、前記酸化皮膜指数ＸとAl箔の電解
エッチング性との具体的な関係として、電解エッチング
前のAl箔表面の任意の場所の酸化皮膜指数ＸｅとＸｃと
の比Ｘｅ／Ｘｃが、0.85〜1.15の範囲、より好ましくは
0.95〜1.05の範囲にある場合に、箔表面の静電容量のば
らつきを防止し、このばらつきを防止する意味で、Al箔
の電解エッチング性が良好となるとしている。As a specific relationship between the oxide film index X and the electrolytic etching property of the Al foil, the ratio Xe / Xc of the oxide film index Xe and Xc at an arbitrary position on the Al foil surface before electrolytic etching is as follows. , 0.85 to 1.15, more preferably
In the range of 0.95 to 1.05, it is described that the electrolytic etching property of the Al foil is improved in the sense that the variation of the capacitance on the foil surface is prevented and the variation is prevented.
【００２１】[0021]
【発明が解決しようとする課題】しかし、この特願平9-
167440号によって、確かに、Al箔の箔表面の静電容量の
ばらつきという点での電解エッチング性は改善されるも
のの、場合によって、必ずしも高い静電容量にならない
場合が生じる。[Problems to be solved by the invention]
According to 167440, although the electrolytic etching property in terms of the variation in the capacitance of the foil surface of the Al foil is improved, in some cases, the capacitance does not always become high.
【００２２】即ち、前記特願平9-167440号では、酸化皮
膜( 酸化アルミニウム）のフーリエ変換赤外吸収スペク
トルの反射ピーク位置（Al−O の最も強い伸縮振動に起
因する反射ピークの波数）は、通常、およそ945 〜955c
m -1の範囲に検出されるとしており、実施例の具体例
も、全てこの945 〜955cm -1の範囲である。That is, in Japanese Patent Application No. 9-167440, the reflection peak position (wave number of the reflection peak due to the strongest stretching vibration of Al—O) in the Fourier transform infrared absorption spectrum of the oxide film (aluminum oxide) is: , Usually around 945 ~ 955c
It is assumed that it is detected in the range of m -1 , and the specific examples of the embodiments are all in the range of 945 to 955 cm -1 .
【００２３】しかし、本発明者らが実際に製造される電
解コンデンサ用Al箔を調査したところによれば、その製
造工程において、前記反射ピークの波数範囲より外れる
酸化皮膜を有するAl箔も製造されることを、まず知見し
た。通常、電解コンデンサ用Al箔の製造は、素材Al板(A
l 箔地) を、熱間圧延および必要により中間的に焼鈍し
ながら複数回の冷間圧延を行い、最終焼鈍して製造す
る。この製造工程において、冷間圧延と最終焼鈍条件あ
るいは途中での保管時間などが微妙に、場合によっては
大きく異なり、これらが影響して、Al箔の表面に生成す
る酸化皮膜の性状が大きく変わり、前記反射ピークの波
数範囲より外れる酸化皮膜を有するAl箔も製造されるも
のと考えられる。However, the present inventors have investigated Al foils for electrolytic capacitors that are actually manufactured, and found that in the manufacturing process, Al foils having an oxide film outside the wave number range of the reflection peak were also manufactured. First, I found out. Usually, the production of aluminum foil for electrolytic capacitors
l) The foil is subjected to cold rolling a plurality of times while hot rolling and, if necessary, intermediate annealing, followed by final annealing. In this manufacturing process, the cold rolling and the final annealing conditions or the storage time in the middle are delicate, and in some cases, greatly different, and due to these, the properties of the oxide film generated on the surface of the Al foil greatly change, It is considered that an Al foil having an oxide film out of the wave number range of the reflection peak is also manufactured.
【００２４】そして、次に、実際に製造される電解コン
デンサ用Al箔においては、前記反射ピークの波数945 〜
955cm -1の範囲より下方に外れる酸化皮膜を有するAl箔
の方が、電解エッチングされた場合に、却って、高い静
電容量が達成されることがあることも知見した。Next, in the Al foil for an electrolytic capacitor actually manufactured, the wave number of the reflection peak is 945 to 945.
It has also been found that the Al foil having an oxide film that falls below the range of 955 cm -1 may achieve a higher capacitance when electrolytically etched instead.
【００２５】したがって本発明は、これらの点に鑑み、
前記従来技術の問題点を克服し、電解エッチングムラが
無く、高い静電容量が得られる点で、電解エッチング性
に優れた電解コンデンサ用Al箔を提供することを目的と
する。Accordingly, the present invention has been made in view of these points,
An object of the present invention is to provide an Al foil for an electrolytic capacitor which is excellent in electrolytic etching property in that the problems of the conventional technology are overcome and there is no unevenness in electrolytic etching and a high capacitance can be obtained.
【００２６】[0026]
【課題を解決するための手段】上記の目的を達成するた
めに、本発明に係る電解コンデンサ用Al箔は、電解エッ
チングされる前のAl箔の状態で、箔表面に30〜60Å (オ
ングストローム) の厚みの酸化皮膜を有するとともに、
該酸化皮膜を入射角75度の平行偏光使用によるFTIR (フ
ーリエ変換式赤外分光光度計) により分析した際の波数
が930 〜940cm -1 (カイザー) であることを要旨とす
る。Means for Solving the Problems To achieve the above object,
For example, the Al foil for an electrolytic capacitor according to the present invention is an electrolytic foil.
30-60 Å (o
With an oxide film with a thickness of
The oxide film was subjected to FTIR (Fl
Wave number when analyzed with a (Rie transform infrared spectrophotometer)
930-940cm -1 (Kaiser)
You.
【００２７】前記した通り、実際に製造される電解コン
デンサ用Al箔においては、945 〜955cm -1の範囲の反射
ピークの波数範囲より、上方乃至下方に外れる酸化皮膜
を有するAl箔も製造される。そして、反射ピークの波数
が940cm -1以下の酸化皮膜を有するAl箔の方が、却っ
て、より高い静電容量が達成される。As described above, in an Al foil for an electrolytic capacitor that is actually manufactured, an Al foil having an oxide film that deviates above or below the wave number range of the reflection peak in the range of 945 to 955 cm -1 is also manufactured. . The Al foil having an oxide film having a reflection peak wave number of 940 cm -1 or less achieves a higher capacitance on the contrary.
【００２８】これは、前記特願平9-167440号の通り、酸
化皮膜の緻密さがAl箔の電解エッチング性に影響してい
るものの、前記特願平9-167440号の認識のように、酸化
皮膜が緻密であればあるほど、Al箔の電解エッチング性
が改善されるのではなく、特定の反射ピークの波数範囲
において、それも特願平9-167440号の認識範囲よりもよ
り小さい反射ピークの波数範囲において達成されるもの
である。This is because although the density of the oxide film affects the electrolytic etching property of the Al foil as described in Japanese Patent Application No. 9-167440, as is recognized in Japanese Patent Application No. 9-167440, The denser the oxide film, the better the electrolytic etching properties of the Al foil, but the smaller the reflection range in the wave number range of the specific reflection peak, which is also smaller than the recognition range of Japanese Patent Application No. 9-167440. This is achieved in the peak wavenumber range.
【００２９】[0029]
【発明の実施の形態】本発明のAl箔表面の酸化皮膜の膜
厚は、Ｘ線光電子分光法(XPS) により、比較的簡単に、
かつ精度良く測定することができる。酸化皮膜の膜厚の
測定方法としては、他に、ハンターホール法や静電容量
法等があるが、測定方法が違うと、測定値のバラツキが
生じる場合があるので、本発明のAl箔表面の酸化皮膜の
膜厚は前記XPS により測定するものとする。BEST MODE FOR CARRYING OUT THE INVENTION The thickness of an oxide film on the surface of an Al foil of the present invention can be relatively easily determined by X-ray photoelectron spectroscopy (XPS).
And it can measure accurately. Other methods for measuring the thickness of the oxide film include the Hunter Hall method and the capacitance method, but if the measurement method is different, the measured values may vary. The thickness of the oxide film shall be measured by XPS.
【００３０】具体的な測定方法は、酸化皮膜中のAl原子
から放出され、XPS 検出器で観測される光電子数(NOX)
と、下地Al基板中Al原子から放出され、XPS 検出器で観
測される光電子数(NAl) とを用い、d=20 cosθ In(1.15
NOX/NAl＋1)の算出式 (但し、θは光電子の検出角度)
により、酸化皮膜の膜厚d(Å: オングストローム) を算
出した。A specific measuring method is as follows: the number of photoelectrons (N OX ) emitted from Al atoms in an oxide film and observed by an XPS detector
And the number of photoelectrons (N Al ) emitted from Al atoms in the underlying Al substrate and observed by the XPS detector, d = 20 cos θ In (1.15
N OX / N Al +1) (where θ is the photoelectron detection angle)
Thereby, the thickness d (Å: Angstroms) of the oxide film was calculated.
【００３１】一方、Al箔表面の酸化皮膜の膜質（緻密
さ）は、酸化皮膜を入射角75度の平行偏光使用によるFT
IR (フーリエ変換式赤外分光光度計) により、入射角75
度の平行偏光使用により分析した際の、赤外吸収スペク
トルの反射ピーク位置（Al−Oの最も強い伸縮振動に起
因する反射ピークの波数）、即ち反射ピークの波数によ
り測定できる。On the other hand, the film quality (density) of the oxide film on the surface of the Al foil is determined by using an FT by using parallel polarized light having an incident angle of 75 degrees.
Incident angle of 75 by IR (Fourier transform infrared spectrophotometer)
It can be measured by the reflection peak position of the infrared absorption spectrum (wave number of the reflection peak caused by the strongest stretching vibration of Al—O), that is, the wave number of the reflection peak, when analyzed by using parallel polarized light.
【００３２】このAl箔表面の酸化皮膜の反射ピークの波
数が930cm -1 (カイザー) 未満、あるいは940cm -1を越
える場合、Al箔の電解エッチング性は劣り、電解エッチ
ング後の箔に、電解エッチングムラが生じ、高い静電容
量が得られない。したがって、反射ピークの波数は930
〜940cm -1の範囲とする。When the wave number of the reflection peak of the oxide film on the surface of the Al foil is less than 930 cm -1 (Kaiser) or more than 940 cm -1 , the electrolytic etching property of the Al foil is inferior, and the foil after the electrolytic etching is subjected to electrolytic etching. Unevenness occurs and a high capacitance cannot be obtained. Therefore, the wave number of the reflection peak is 930
The range is 940940 cm -1 .
【００３３】因みに、フーリエ変換しない赤外吸収スペ
クトル分析法では、酸化皮膜の膜質（緻密さ）は測定で
きない。即ち、酸化皮膜は100 Å未満の薄膜であり、赤
外吸収スペクトル分析法では、シグナル中のノイズの中
から微小な酸化アルミニウムのピークを検出するため
に、多大なシグナルの積算が必要となる。この点、フー
リエ変換赤外吸収スペクトル分析法は、単位シグナル当
たりの測定時間が短いことが特徴であり、多大なシグナ
ルの積算も可能である。一方、フーリエ変換しない赤外
吸収スペクトル分析法では、前記単位シグナル当たりの
測定時間がフーリエ変換赤外吸収スペクトル分析法の10
0 〜1000倍であり、前記多大なシグナルの積算が事実上
不可能である。Incidentally, the infrared absorption spectrum analysis without Fourier transform cannot measure the quality (density) of the oxide film. That is, the oxide film is a thin film having a thickness of less than 100 °, and in the infrared absorption spectrum analysis method, a large amount of signal integration is required to detect minute aluminum oxide peaks from noise in the signal. In this regard, the Fourier transform infrared absorption spectrum analysis method is characterized in that the measurement time per unit signal is short, and a large amount of signals can be integrated. On the other hand, in the infrared absorption spectrum analysis method without Fourier transform, the measurement time per unit signal is 10 times that of the Fourier transform infrared absorption spectrum analysis method.
0 to 1000 times, and it is virtually impossible to integrate the large signal.
【００３４】また、本発明においては、以上説明した通
り、Al箔表面の酸化皮膜の均質性が確保され、電解エッ
チング性が良好となるため、高い静電容量が達成できる
効果を有する。これは、電解エッチング性が良好となる
結果、電解エッチング工程において、Al箔表面に微細な
エッチングピットが多数均一に形成されるとともに、箔
の厚み方向に深いエッチングピットが順次形成され、電
解エッチングによるAl箔の減量を必要以上に大きくする
ことなく、単位エッチング減量当たりの静電容量を大き
くすることができるからである。Further, in the present invention, as described above, the uniformity of the oxide film on the surface of the Al foil is ensured and the electrolytic etching property is improved, so that there is an effect that a high capacitance can be achieved. This is because, as a result of improving the electrolytic etching property, in the electrolytic etching step, a large number of fine etching pits are uniformly formed on the surface of the Al foil, and deep etching pits are sequentially formed in the thickness direction of the foil. This is because the capacitance per unit etching loss can be increased without increasing the loss of the Al foil more than necessary.
【００３５】本発明の電解コンデンサ用Al箔を得る製造
方法について以下に説明する。まず、所定厚みのAl箔圧
延コイルを得るまでは、常法により製造可能である。即
ち、前記高純度のAl鋳塊を、均熱処理後熱間圧延し、必
要により中間焼鈍しながら、複数回の冷間圧延で所定厚
みに、およびスリットして所定幅のAl箔圧延コイルとす
る。このAl箔圧延コイルは、前記冷間圧延後、最終焼鈍
し、電解エッチングされてAl箔表面に多数のエッチング
ピットが設けられ電極用の箔とされるが、陽極用に用い
られる場合には、更に誘電体酸化皮膜がエッチングピッ
トに設けられる。The method for producing the Al foil for an electrolytic capacitor of the present invention will be described below. First, it can be manufactured by an ordinary method until an Al foil rolled coil having a predetermined thickness is obtained. That is, the high-purity Al ingot is hot-rolled after soaking, and, if necessary, with intermediate annealing, a plurality of cold-rollings to a predetermined thickness, and slits into a predetermined width Al foil rolled coil. . This Al foil rolled coil, after the cold rolling, final annealing, electrolytic etching is provided with a number of etching pits on the Al foil surface to be a foil for the electrode, when used for the anode, Further, a dielectric oxide film is provided on the etching pit.
【００３６】このような電解コンデンサ用Al箔の製造方
法において、Al箔表面の酸化皮膜の反射ピークの波数を
930 〜940cm -1の範囲内にするためには、前記冷間圧延
後、最終焼鈍し、電解エッチングされるまでの工程が重
要となる。即ち、Al箔表面の酸化皮膜を前記範囲内とす
るための手段は、以下の〜に記載する手段を前記冷
間圧延後、最終焼鈍し、電解エッチングされるまでの工
程に盛り込み、最終焼鈍後のAl箔の酸化皮膜の反射ピー
クの波数を930 〜940cm -1の範囲内にするか、または、
最終焼鈍後に前記FTIRにより分析した際の波数が940cm
-1を越える酸化皮膜を、電解エッチング前に、燐酸ソー
ダ系や苛性ソーダ系などの水溶液で予め乃至予備的にエ
ッチングすることにより前記波数範囲とすることが好ま
しい。In such a method for producing an Al foil for an electrolytic capacitor, the wave number of the reflection peak of the oxide film on the surface of the Al foil is reduced.
In order to keep the thickness within the range of 930 to 940 cm -1 , steps from the cold rolling to the final annealing and electrolytic etching are important. That is, the means for keeping the oxide film on the surface of the Al foil within the above-mentioned range includes the means described in the following to after the cold rolling, final annealing, and incorporating into the steps until electrolytic etching, after the final annealing. The reflection peak wave number of the oxide film of the aluminum foil is in the range of 930 to 940 cm -1 or
Wave number when analyzed by FTIR after final annealing is 940 cm
It is preferable that the oxide film exceeding -1 is preliminarily or preliminarily etched with an aqueous solution of a sodium phosphate or caustic soda before the electrolytic etching so as to have the wave number range.
【００３７】箔圧延から焼鈍までの最終焼鈍前のAl箔
のコイル状での保管時間を短くしてコイル状での酸化皮
膜の成長を抑制する。最終焼鈍前に燐酸ソーダ系や苛
性ソーダ系などの水溶液でAl箔コイル表面のエッチング
洗浄乃至酸化皮膜の除去を行う。あるいは、最終焼鈍
前の焼鈍を不活性ガス雰囲気下で行う、最終焼鈍前の
焼鈍を真空引き下で行い焼鈍中のコイルから発生するガ
スをより多く除去し、焼鈍中、コイル状での酸化皮膜の
成長を抑制する。更に、最終焼鈍から電解エッチング
までのAl箔のコイル状での保管時間を短くしてコイル状
での酸化皮膜の成長を抑制する。Al箔コイルでの保管
雰囲気を空調する。The storage time of the Al foil in the coil shape before the final annealing from the foil rolling to the annealing is shortened to suppress the growth of the oxide film in the coil shape. Before the final annealing, the surface of the Al foil coil is etched and cleaned or the oxide film is removed with an aqueous solution of a sodium phosphate or caustic soda. Alternatively, the annealing before the final annealing is performed in an inert gas atmosphere, the annealing before the final annealing is performed under vacuum to remove more gas generated from the coil during the annealing, and the oxide film in a coil shape during the annealing. Suppress the growth of. Further, the storage time of the Al foil from the final annealing to the electrolytic etching in a coil shape is shortened to suppress the growth of the oxide film in the coil shape. Air-condition the storage atmosphere with Al foil coils.
【００３８】これらの手段を、最終焼鈍前のAl箔製造工
程上で、Al箔表面に酸化皮膜が生成する可能性のある工
程条件を改善する、あるいは不適当な酸化皮膜が生成し
た場合にこれを除去するために用いる。勿論、これらの
手段は各々酸化皮膜制御の決め手となるものではなく、
実際にはAl箔製造工程の環境や条件に応じて、本発明Al
箔の条件を満足すべく、これらの手法を適宜組み合わせ
て適宜用いる。[0038] These measures are used to improve the process conditions in which an oxide film may be formed on the surface of the Al foil in the Al foil manufacturing process before the final annealing, or when an inappropriate oxide film is formed, Used to remove. Of course, each of these means is not decisive for controlling the oxide film.
Actually, according to the environment and conditions of the Al foil manufacturing process, the present invention Al
In order to satisfy the condition of the foil, these methods are appropriately combined and used as appropriate.
【００３９】本発明に使用するAl箔は、陽極用にはAl純
度99.96%以上、より好ましくは99.9% 以上、また、陰極
用には99% 以上、より好ましくは99.8% 以上、の高純度
Al箔を使用するのが好ましい。また、JIS H 4170(1994)
で規定されたAl純度99.99%以上（合金番号IN99）や、Al
純度99.90%以上（合金番号IN90）などを用いることも好
ましいが、要は、使用電圧や電極などの用途や要求特性
条件によって、適宜選択される。The Al foil used in the present invention has a high purity of 99.96% or more, more preferably 99.9% or more, for the anode, and 99% or more, more preferably 99.8% or more for the cathode.
It is preferable to use Al foil. Also, JIS H 4170 (1994)
Al purity 99.99% or more (alloy number IN99) specified in
It is also preferable to use a purity of 99.90% or more (alloy No. IN90) or the like, but the point is that it is appropriately selected according to the application such as the working voltage and the electrode and required characteristic conditions.
【００４０】また、Al箔中に含まれやすい、Fe、Si、Cu
等の不純物は、これら不純物による粗大な析出物がAl箔
表面に存在していると、電解エッチングを施した際に粗
大孔（粗大エッチングピット）が生じるという問題を生
じる。したがって、前記従来技術と同様、Fe、Si、Cu等
の不純物は、これらの不純物量を各々70ppm 以下に規制
することが好ましい。In addition, Fe, Si, Cu
If impurities such as impurities are present on the surface of the Al foil, there is a problem that large holes (coarse etching pits) are generated when electrolytic etching is performed. Therefore, as in the above-described prior art, it is preferable that impurities such as Fe, Si, Cu and the like are each regulated to an amount of 70 ppm or less.
【００４１】本発明による電解コンデンサ用Al箔は、電
極箔として、中低圧用あるいは高圧用の陽極用にも陰極
用にも用いることができる。陽極に用いる場合には、塩
酸水溶液などの塩素含有水溶液で、直流または交流電解
エッチングをした後、化成処理液として、ホウ酸系（ホ
ウ酸、ホウ酸アンモニウム、ホウ酸−ホウ砂）、燐酸塩
系（第１燐酸アンモニウム、第２燐酸アンモニウム、第
３燐酸アンモニウム、燐酸ナトリウム）、アジピン酸系
（アジピン酸、アジピン酸アンモニウム）、非水溶液系
（エチレングリコール）を用いた化成処理（陽極酸化処
理）工程により誘電体酸化皮膜が形成される。The Al foil for an electrolytic capacitor according to the present invention can be used as an electrode foil for an anode or a cathode for medium / low pressure or high pressure. When used for the anode, after performing direct current or alternating current electrolytic etching with a chlorine-containing aqueous solution such as a hydrochloric acid aqueous solution, boric acid (boric acid, ammonium borate, boric acid-borax), phosphate, Chemical treatment (anodic oxidation treatment) using a system (ammonium primary phosphate, ammonium phosphate dibasic, ammonium tertiary phosphate, sodium phosphate), adipic acid system (adipic acid, ammonium adipate), or non-aqueous system (ethylene glycol) The process forms a dielectric oxide film.
【００４２】[0042]
【実施例】純度99.98%(Fe,Si,Cu の不純物量は各々70pp
m 以下) のAl鋳塊を、550 ℃で5時間均熱処理後、圧下
率5 〜50% で熱間圧延し、圧下率25〜60% で冷間圧延
し、スリットして、幅500mm 、箔厚100 μm のAl箔圧延
コイルとした。この冷間圧延後のAl箔コイルを540 ℃で
最終焼鈍した後、電解エッチング前に燐酸ソ−ダ系水溶
液(PH11)により予備エッチング (洗浄) を施した。そし
て、予備エッチングを施さないものおよびエッチング時
間を種々変え、Al箔の酸化皮膜の酸化皮膜の緻密さを変
化させた。[Example] 99.98% purity (impurity of Fe, Si, Cu is 70pp each)
m) at 550 ° C for 5 hours, then hot-rolled at a reduction of 5 to 50%, cold-rolled at a reduction of 25 to 60%, slit, 500mm wide, foil A 100 μm thick aluminum foil rolled coil was used. After the cold-rolled Al foil coil was finally annealed at 540 ° C., it was pre-etched (washed) with an aqueous sodium phosphate solution (PH11) before electrolytic etching. Then, the density of the oxide film of the Al foil was changed by changing variously those without pre-etching and the etching time.
【００４３】そして、これらAl箔の酸化皮膜を、入射角
75度の平行偏光使用によるFTIRにより、反射ピークの波
数を測定し、図3 にFTIR反射ピークの一部を例示する通
り、反射ピークの波数が異なるもの( 図3 において、A
は956cm -1、B は949cm -1、C は938cm -1、D は934cm
-1) を選択して電解エッチング用の供試材とした。Then, the oxide film of these Al foils was
The wave number of the reflection peak was measured by FTIR using 75-degree parallel polarized light, and the wave number of the reflection peak was different as shown in FIG.
Is 956 cm -1 , B is 949 cm -1 , C is 938 cm -1 , D is 934 cm
-1 ) was selected as a test material for electrolytic etching.
【００４４】なお、FTIR法の試験条件は、炭酸ガスおよ
び水分によるノイズを除去するために、試料室内を窒素
ガスパージし、高感度反射法（入射角＝75℃、平行偏
光) により測定した。ディテクター (検出器) は広範囲
(400〜4000cm-1) のものを使用し、S ／N 比が100/1 に
なるまでスペクトルを積算した。試料面積は、2.5 ×5c
m とした。The test conditions of the FTIR method were measured by a high-sensitivity reflection method (incident angle = 75 ° C., parallel polarized light) by purging the sample chamber with nitrogen gas in order to remove noise due to carbon dioxide gas and moisture. Wide range of detectors
(400-4000 cm -1 ), and spectra were integrated until the S / N ratio became 100/1. Sample area is 2.5 x 5c
m.
【００４５】更に、これら供試材を、液温85℃の5wt%塩
酸、20wt% 硫酸を含む電解エッチング液で、電流密度20
A/dm2 の直流電流を通じて1.5 分間の第1 段電解エッチ
ングを行い、次いで、液温85℃の5wt%塩酸、0.2wt%しゅ
う酸を含む電解エッチング液で、電流密度5A/dm2の直流
電流を通じて9 分間の第2 段電解エッチングを実施し
た。これら電解エッチング後の供試材を、硼酸100gと五
硼酸アンモニウム0.9gを1リットル 当たりに含む87.5℃の純
水中で、電流密度750mA ／3 供試材片の直流電流を通じ
て9 分間の化成処理( 陽極酸化処理) して誘電体( バリ
ヤー型酸化皮膜)を設けた。Further, these test materials were subjected to a current density of 20% with an electrolytic etching solution containing 5 wt% hydrochloric acid and 20 wt% sulfuric acid at a liquid temperature of 85 ° C.
Performing a first stage electrolytic etching for 1.5 minutes through a direct current of A / dm 2, then the liquid 5 wt% hydrochloric acid temperature 85 ° C., in an electrolytic etching solution containing 0.2 wt% oxalic acid, direct current density of 5A / dm 2 The second-stage electrolytic etching was performed for 9 minutes using electric current. The sample after electrolytic etching was subjected to a chemical conversion treatment in pure water at 87.5 ° C containing 100 g of boric acid and 0.9 g of ammonium pentaborate per liter for 9 minutes through a direct current of 750 mA / 3 of the test piece. (Anodizing treatment) to provide a dielectric (barrier type oxide film).
【００４６】この供試材について、幅1cm の試料とし、
折曲強度試験法により、MIT 型試験機(JIS P8115) を用
い、箔折曲げ面の曲率半径を1mm 、引張荷重を250gと
し、始め45度に倒し、もとに戻して反対方向に45度に倒
し、またもとに戻す、これを1回として、箔が切断する
まで繰り返した場合の回数を測定し、折曲強度として評
価した。これらの結果を表1 に示す。With respect to this test material, a sample having a width of 1 cm was prepared.
According to the bending strength test method, using a MIT type testing machine (JIS P8115), the radius of curvature of the foil bending surface is 1 mm, the tensile load is 250 g, fall down to 45 degrees at the beginning, return to the original position, and reverse to 45 degrees The number of times this was repeated until the foil was cut was measured and evaluated as bending strength. Table 1 shows the results.
【００４７】また、供試材について、等価直列回路( 測
定液; 硼酸 50gと硼砂45g を1リットル当たりに含む30℃の
純水中で、直流バイアスを1.5V印加して静電容量 (μF/
cm2)を各々測定した。また、走査型電子顕微鏡 (500
倍) にて、電解エッチング後の供試材表面を観察するこ
とにより供試材表面の溶け残りむらを評価し、また、電
解エッチング後の供試材表面を電解研磨した後の表面を
同じく観察して、エッチングピットを評価し、これによ
っても電解エッチング性を評価した。また、電解エッチ
ングでの単位エッチング減量当たりの静電容量 (μF/m
g) も調査した。これらの結果を表1 に示す。The test material was subjected to an equivalent series circuit (measurement solution; a pure water at 30 ° C. containing 50 g of boric acid and 45 g of borax per liter) at a direct current bias of 1.5 V and a capacitance (μF /
cm 2 ) was measured for each. Scanning electron microscope (500
At times, the unmelted unevenness of the surface of the test material was evaluated by observing the surface of the test material after electrolytic etching, and the surface after electrolytic polishing of the test material surface after electrolytic etching was also observed. Then, the etching pit was evaluated, and the electrolytic etching property was also evaluated. In addition, the capacitance per unit etching loss (μF / m
g) was also investigated. Table 1 shows the results.
【００４８】表1 から明らかな通り、XPS 法で30〜60Å
の範囲の厚みの酸化皮膜を有するとともに、該酸化皮膜
の反射ピークの波数が930 〜940cm -1の範囲の酸化皮膜
を有する発明例No.1〜4 はエッチング表面の溶け残りむ
らが無く、折曲強度と静電容量および単位エッチング減
量当たりの静電容量も著しく高い。なお、発明例No.2は
電解エッチング前に予備エッチングを施さず、最終焼鈍
後の状態で酸化皮膜の反射ピークの波数が発明範囲内に
あったものである。また、発明例No.1、3 、4は最終焼
鈍後の状態で酸化皮膜の反射ピークの波数が940cm -1を
越えていたものを、予備エッチングにより発明範囲内と
したものである。As is evident from Table 1, the XPS method was used for 30-60 ° C.
Inventive Examples Nos. 1 to 4 having an oxide film having a thickness in the range of, and having an oxide film having a reflection peak wave number in the range of 930 to 940 cm -1 have no unevenness in the undissolved etching surface and are folded. The bending strength and capacitance and the capacitance per unit etching loss are also significantly higher. In Invention Example No. 2, the preliminary etching was not performed before the electrolytic etching, and the wave number of the reflection peak of the oxide film in the state after the final annealing was within the range of the invention. In addition, Invention Examples Nos. 1, 3 and 4 are those in which the wave number of the reflection peak of the oxide film exceeds 940 cm -1 in the state after the final annealing was brought into the invention range by preliminary etching.
【００４９】また、図1(a)に発明例No.2の、走査型電子
顕微鏡 (500 倍) による電解エッチング後の供試材表面
の観察結果、図1(b)に発明例No.2の、走査型電子顕微鏡
(500倍) による電解エッチング後の供試材表面を電解研
磨した後の観察結果を示す。なお、図1 はこれら走査型
電子顕微鏡写真を図面化したものである( 図2 も同様)
。この図1 からも、発明例では、供試材 (箔) 表面の
溶け残りむら (図1(a)の細かい横線が溶解部分、横線間
の白抜き部分が溶け残り部分) やエッチングピット (図
1(b)の丸い点が各々エッチングピット) の不均一分布が
なく、エッチングピットが、箔表面に微細にかつ均一に
分散していることが分かる。FIG. 1 (a) shows the result of observing the surface of the test material after electrolytic etching of Invention Example No. 2 using a scanning electron microscope (× 500), and FIG. 1 (b) shows Invention Example No. 2. Scanning electron microscope
The observation results after electrolytic polishing of the test material surface after electrolytic etching by (500 times) are shown. Fig. 1 is a drawing of these scanning electron micrographs (similar to Fig. 2).
. As can be seen from Fig. 1, in the example of the invention, the unmelted unevenness on the surface of the test material (foil) (the fine horizontal line in Fig. 1 (a) is the dissolved part, the white part between the horizontal lines is the unmelted part) and the etching pit (Fig.
It can be seen that there is no non-uniform distribution of the (1b) round dots in each etching pit) and the etching pits are finely and uniformly dispersed on the foil surface.
【００５０】これに対し、酸化皮膜厚みが本発明範囲を
外れる、酸化皮膜の反射ピークの波数が本発明範囲を外
れる比較例No.5〜8 は、発明例に比して、エッチング表
面の溶け残りむらが有り、折曲強度および静電容量、更
に単位エッチング減量当たりの静電容量も低い。また、
図2(a)の比較例No.7の、走査型電子顕微鏡 (500 倍)に
よる電解エッチング後の供試材表面観察結果、更に、図
2(b)の発明例No.2の、走査型電子顕微鏡 (500 倍) によ
る電解エッチング後の供試材表面を電解研磨した後の観
察結果からも、比較例では、供試材表面の溶け残りむら
(図2(a)の網目模様が溶解部分、網目模様間の白抜き部
分が溶け残り部分) やエッチングピット(図2(b)の丸い
点が各々エッチングピット) の不均一分布が有ることが
分かる。On the other hand, in Comparative Examples Nos. 5 to 8 in which the thickness of the oxide film was out of the range of the present invention and the wave number of the reflection peak of the oxide film was out of the range of the present invention, the melting of the etched surface was smaller than that of the invention. There is residual unevenness, and the bending strength and capacitance, and further, the capacitance per unit etching loss are low. Also,
Fig. 2 (a) shows the results of observation of the surface of the test material after electrolytic etching by using a scanning electron microscope (500x) for Comparative Example No. 7
In Comparative Example, the melting of the surface of the test material was observed from the results of observation of the surface of the test material after electrolytic etching using a scanning electron microscope (500 ×) of Invention Example No. 2 of 2 (b). Remaining unevenness
(Dissolved portions of the mesh pattern in Fig. 2 (a), undissolved portions in the white portions between the mesh patterns) and non-uniform distribution of etching pits (each round dot in Fig. 2 (b) is an etching pit) may be present. I understand.
【００５１】[0051]
【表１】 [Table 1]
【００５２】[0052]
【発明の効果】以上説明したように、本発明は、電解エ
ッチング性に優れ、強度が高く、しかも静電容量の高い
電解コンデンサ用Al箔を提供することができる点で工業
的な意義は大きい。As described above, the present invention has great industrial significance in that it can provide an Al foil for an electrolytic capacitor having excellent electrolytic etching properties, high strength, and high capacitance. .
【図１】本発明例に係り、走査型電子顕微鏡による電解
エッチング後の供試材表面写真を図面化した説明図で、
図1(a)は電解エッチングまま、図1(b)は電解研磨した後
であるFIG. 1 is an explanatory view illustrating a photograph of a surface of a test material after electrolytic etching with a scanning electron microscope according to the present invention,
FIG. 1 (a) is after electrolytic etching, and FIG. 1 (b) is after electrolytic polishing.
【図２】比較例に係り、走査型電子顕微鏡による電解エ
ッチング後の供試材表面写真を図面化した説明図で、図
2(a)は電解エッチングまま、図2(b)は電解研磨した後で
あるFIG. 2 is an explanatory diagram illustrating a photograph of a surface of a test material after electrolytic etching by a scanning electron microscope according to a comparative example.
2 (a) is electrolytically etched, and FIG.2 (b) is after electrolytic polishing
【図３】Al箔の酸化皮膜を、FTIR分析した際の反射ピー
クを示す説明図であるFIG. 3 is an explanatory diagram showing a reflection peak when an oxide film of an Al foil is subjected to FTIR analysis.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） Ｃ２２Ｆ 1/04 Ｃ２２Ｆ 1/04 Ｋ Ｃ２５Ｆ 3/04 Ｃ２５Ｆ 3/04 Ａ Ｈ０１Ｇ 9/055 Ｈ０１Ｇ 9/04 ３４６ ──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. 7 Identification symbol FI Theme coat ゛ (Reference) C22F 1/04 C22F 1/04 K C25F 3/04 C25F 3/04 A H01G 9/055 H01G 9/04 346
Claims (8)
箔であって、箔表面に30〜60Å (オングストローム) の
厚みの酸化皮膜を有するとともに、該酸化皮膜を入射角
75度の平行偏光使用によるFTIR (フーリエ変換式赤外分
光光度計) により分析した際の波数が930 〜940cm -1で
あることを特徴とする電解コンデンサー用アルミニウム
箔。1. An aluminum foil before electrolytic etching, which has an oxide film having a thickness of 30 to 60 ° (angstrom) on the surface of the aluminum foil, and the oxide film has an incident angle.
An aluminum foil for electrolytic capacitors, characterized in that the wave number when analyzed by FTIR (Fourier transform infrared spectrophotometer) using parallel polarized light at 75 degrees is 930 to 940 cm -1 .
地を、必要により焼鈍しながら、冷間圧延するとともに
最終焼鈍して製造されたものである請求項１に記載の電
解コンデンサー用アルミニウム箔。2. The aluminum foil for an electrolytic capacitor according to claim 1, wherein the aluminum foil is produced by subjecting an aluminum foil base to cold rolling and final annealing while annealing as necessary.
ウム箔の酸化皮膜である請求項１または２に記載の電解
コンデンサー用アルミニウム箔。3. The aluminum foil for an electrolytic capacitor according to claim 1, wherein the oxide film is an oxide film of an aluminum foil after final annealing.
により分析した際の波数が940cm -1を越える酸化皮膜
を、予備エッチングにより前記波数範囲としたものであ
る請求項１乃至３の何れか１項に記載の電解コンデンサ
ー用アルミニウム箔。4. The method according to claim 1, wherein the oxide film is formed after the final annealing.
The aluminum foil for an electrolytic capacitor according to any one of claims 1 to 3, wherein an oxide film having a wave number exceeding 940 cm -1 when analyzed by means of pre-etching is set to the wave number range.
である請求項１乃至４の何れか１項に記載の電解コンデ
ンサー用アルミニウム箔。5. The aluminum foil for an electrolytic capacitor according to claim 1, wherein the purity of the aluminum foil is 99.6% or more.
である請求項１乃至５の何れか１項に記載の電解コンデ
ンサー用アルミニウム箔。6. The aluminum foil for an electrolytic capacitor according to claim 1, wherein the purity of the aluminum foil is 99.99% or more.
e、Si、Cuの量を各々70ppm 以下とする請求項１乃至６
の何れか１項に記載の電解コンデンサー用アルミニウム
箔。7. F which is an impurity in the aluminum foil
The amount of each of e, Si, and Cu is 70 ppm or less.
The aluminum foil for an electrolytic capacitor according to any one of the above.
00ppm を含む請求項１乃至７の何れか１項に記載の電解
コンデンサー用アルミニウム箔。8. The method according to claim 1, wherein the aluminum foil further comprises Pb: 0.1 to 10
The aluminum foil for an electrolytic capacitor according to any one of claims 1 to 7, which contains 00 ppm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3415799A JP2000232038A (en) | 1999-02-12 | 1999-02-12 | Aluminum foil for electrolytic capacitor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3415799A JP2000232038A (en) | 1999-02-12 | 1999-02-12 | Aluminum foil for electrolytic capacitor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2000232038A true JP2000232038A (en) | 2000-08-22 |
Family
ID=12406380
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3415799A Pending JP2000232038A (en) | 1999-02-12 | 1999-02-12 | Aluminum foil for electrolytic capacitor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2000232038A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004186696A (en) * | 2002-12-05 | 2004-07-02 | Acktar Ltd | Electrode for electrolytic capacitor, and manufacturing method thereof |
| JP2007180082A (en) * | 2005-12-27 | 2007-07-12 | Nichicon Corp | Method of manufacturing electrode foil for electrolytic capacitor |
-
1999
- 1999-02-12 JP JP3415799A patent/JP2000232038A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004186696A (en) * | 2002-12-05 | 2004-07-02 | Acktar Ltd | Electrode for electrolytic capacitor, and manufacturing method thereof |
| JP2007180082A (en) * | 2005-12-27 | 2007-07-12 | Nichicon Corp | Method of manufacturing electrode foil for electrolytic capacitor |
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