JP4452355B2 - Aluminum foil for electrolytic capacitor electrode - Google Patents
Aluminum foil for electrolytic capacitor electrode Download PDFInfo
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- JP4452355B2 JP4452355B2 JP32673899A JP32673899A JP4452355B2 JP 4452355 B2 JP4452355 B2 JP 4452355B2 JP 32673899 A JP32673899 A JP 32673899A JP 32673899 A JP32673899 A JP 32673899A JP 4452355 B2 JP4452355 B2 JP 4452355B2
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- 239000011888 foil Substances 0.000 title claims description 49
- 229910052782 aluminium Inorganic materials 0.000 title claims description 39
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 title claims description 39
- 239000003990 capacitor Substances 0.000 title claims description 23
- 238000005530 etching Methods 0.000 description 15
- 238000000034 method Methods 0.000 description 12
- 238000000137 annealing Methods 0.000 description 11
- 238000007373 indentation Methods 0.000 description 7
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 238000000866 electrolytic etching Methods 0.000 description 3
- 238000005096 rolling process Methods 0.000 description 3
- 208000020401 Depressive disease Diseases 0.000 description 2
- 238000005422 blasting Methods 0.000 description 2
- 238000005097 cold rolling Methods 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005098 hot rolling Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000007788 roughening Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 229910052797 bismuth Inorganic materials 0.000 description 1
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 1
- 239000004327 boric acid Substances 0.000 description 1
- 238000003486 chemical etching Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000005238 degreasing Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 230000036571 hydration Effects 0.000 description 1
- 238000006703 hydration reaction Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
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Description
【０００１】
【発明の属する技術分野】
本発明は、電解コンデンサの電極として使用されるアルミニウム箔に関するものである。
【０００２】
なお、この明細書において、「アルミニウム」の語はアルミニウムおよびその合金の両者を含む意味で用いられる。
【０００３】
【従来の技術】
近年、電子機器の小型化に伴い、電子機器に組み込まれる電解コンデンサ電極用アルミニウム箔についても静電容量の向上が要望されている。
【０００４】
通常、電解コンデンサ電極に使用されるアルミニウム材は、拡面率を高めて静電容量を向上させるためにエッチング処理される。そして、エッチング処理により形成されるエッチングピットの深さが深いほど拡面率が高くなるため、エッチング適性を改善すべくエッチング処理の前工程としてアルミニウム材に様々な処理が行われている。例えば、（１００）結晶方位の調整、アルミニウム材へのＰｂ、Ｂｉ等微量不純物の添加による組成の調整、最終焼鈍前の脱脂洗浄、最終焼鈍前の水和処理と最終焼鈍での結晶性酸化膜の形成処理、最終焼鈍前の酸化処理等である（特公昭５８−３４９２５号、特開平３−１２２２６０号他）。
【０００５】
また、単に各エッチングピットの深さを深くするだけではアルミニウム箔の拡面率の向上が十分ではなく、さらに拡面率を向上させるためには局部エッチング、未エッチング、表面溶解を少なくして、エッチングピットをエッチング面で均一に、かつ高密度に発生させる必要がある。前述されたような種々の方法は、均一にエッチングピットを発生させるという点で十分ではない。
【０００６】
そこで、本出願人は、特開平６−１４５９２２号において、箔表面にエッチピットの発生核となる微細な突起を設けてエッチングによる拡面率の向上を図る技術を提案した。また、特開平６−３１０３８４号においては、箔表面に凹みを付与してこれをエッチピットの発生核とする技術が提案されており、軽金属学会第８１回秋期大会（１９９１年１１月）概要集第７５頁では、アルミニウム箔表面の半球状、半立方体状の粗面化（凹み）とエッチング性との関係が述べられている。
【０００７】
【発明が解決しようとする課題】
しかしながら、箔表面に突起や凹みを付与しただけでは、増大しつつある高静電容量化への要望に応えることができない。
【０００８】
この発明は、このような技術背景に鑑みて、深いエッチングピットを均一に発生させて確実に拡面率を高め、静電容量のさらなる増大を図ることができる電解コンデンサ電極用アルミニウム箔を提供しようとするものである。
【０００９】
【課題を解決するための手段】
前記目的を達成するために、この発明の第１の電解コンデンサ電極用アルミニウム箔は、表面に円相当径の開口径（ｄ1）が０．１〜５μｍの一次凹み（１）が多数形成されたアルミニウム箔であって、前記一次凹み（１）のうち、その最大内部径（ｄ2）が前記開口径（ｄ1）よりも大きく内部が膨らんだ形状で、開口径（ｄ1）／最大内部径（ｄ2）が０．９未満であるという条件を満たすものの数が２０％以上存在することを基本要旨とする。
【００１０】
また、第２の電解コンデンサ電極用アルミニウム箔は、表面に円相当径の開口径（ｄ1）が０．１〜５μｍの一次凹み（１）が多数形成されたアルミニウム箔であって、前記一次凹み（１）のうち、その内部に開口する二次凹み（２）を１個以上有し、かつ前記二次凹み（２）の少なくとも１個の開口径（ｄ3）が前記一次凹み（１）の開口径（ｄ1）の１／２以下であるという条件を満たすものの数が２０％以上存在することを基本要旨とする。
【００１１】
また、第３の電解コンデンサ電極用アルミニウム箔は、表面に円相当径の開口径（ｄ1）が０．１〜５μｍの一次凹み（１）が多数形成されたアルミニウム箔であって、前記一次凹み（１）のうち、その最大内部径（ｄ2）が前記開口径（ｄ1）よりも大きく内部が膨らんだ形状で、開口径（ｄ1）／最大内部径（ｄ2）が０．９未満であるという条件を満たすものと、その内部に開口する二次凹み（２）を１個以上有し、かつ前記二次凹み（２）の少なくとも１個の開口径（ｄ3）が前記一次凹み（１）の開口径（ｄ1）の１／２以下であるという条件を満たすものとが合計数で２０％以上存在することを基本要旨とする。
【００１２】
図１〜図３に示すように、この発明の３種類の電解コンデンサ電極用アルミニウム箔は、箔表面に開口してエッチピットの発生核となる一次凹み（１）が多数形成されている。そして、その開口径（ｄ1）を規定し、かつ詳細な形態を規定することにより、深いピットを均一かつ高密度に形成して確実に拡面率の向上を図ることができる。
【００１３】
この発明の３種類全ての箔において、一次凹み（１）の開口径（ｄ1）を円相当径で０．１〜５μｍに規定する。開口径（ｄ1）が０．１μｍよりも小さい場合はエッチピットの発生核となり難く、５μｍを超えるとピットが粗大化して却って拡面率が低下する。一次凹み（１）の開口径（ｄ1）の好ましい下限値は０．２μｍであり、上限値は３μｍである。
【００１４】
第１の電解コンデンサ電極用アルミニウム箔は、一次凹み（１）の開口径（ｄ1）を前記範囲に規定した上で、前記一次凹み（１）のうち、その最大内部径（ｄ2）が前記開口径（ｄ1）よりも大きく内部が膨らんだ形状で、その開口径（ｄ1）／最大内部径（ｄ2）が０．９未満であるという条件を満たすもを全体数の２０％以上存在させることにより、一次凹み（１）内部の拡大して深いエッチピットの発生を促進する。開口径（ｄ1）／最大内部径（ｄ2）の好ましい上限値は０．８であり、前記条件を満たす一次凹み（１）数は４０％以上存在していることが好ましい
第２の電解コンデンサ電極用アルミニウム箔は、図３に示すように、前記一次凹み（１）の内部に、該一次凹み（１）内部に開口する二次凹み（２）が１個以上形成されたものであり、一次凹み（１）内の表面積を拡大して深いエッチピットの均一高密度発生を促進する。少なくとも１個の二次凹み（２）の開口径（ｄ3）が前記一次凹み（１）の開口径（ｄ1）の１／２以下である二次凹み（２）を有する一次凹み（１）を全体数の２０％以上存在させることにより、一次凹み（１）内部の表面積の拡大を確かなものとする。前記二次凹み（２）の開口径（ｄ3）の好ましい上限値は一次凹み（１）の開口径（ｄ1）の１／３以下であり、このような二次凹み（２）を有する一次凹み（１）数は４０％以上存在していることが好ましい
第３の電解コンデンサ電極用アルミニウム箔は、一次凹み（１）の開口径（ｄ1）を前記範囲に規定した上で、前記一次凹み（１）の開口径（ｄ1）／最大内部径（ｄ2）および前記二次凹み（２）の開口径（ｄ3）の両方の条件で規定したものであって、いずれかの一方の条件を満たす一次凹み（１）の合計数を２０％以上存在させることにより、深いエッチピットの均一高密度発生を促進する。
【００１５】
さらに、これら３種類の電解コンデンサ電極用アルミニウム箔は、各条件を満たす一次凹み（１）の平均深さ０．２μｍ以上とするとともに、存在密度を７×１０4個／mm2以上とすることにより、一次凹み（１）内部の表面積の拡大を確実にし、ひいてはエッチングによる拡面率の増大、静電容量の増大を確かなものとしている。一次凹み（１）の好ましい平均深さは０．５μｍ以上であり、好ましい存在密度は８×１０4個／mm2以上である。
【００１６】
上述した形状の一次凹み（１）および二次凹み（２）は、アルミニウム鋳塊の面削、熱間圧延、中間焼鈍を含む冷間圧延、箔圧延、最終焼鈍という通常の箔製造過程において、箔圧延後最終焼鈍前に凹みを付与する処理を施すことによって形成される。凹み付与処理は、ブラスト処理後に電解エッチング処理する方法、微細な突起を有する２本のロールに箔を挟み、凹みを転写させた後、ケミカル処理にて粗面化する方法等を例示できる。
【００１７】
また、箔材料となるアルミニウムは、純度９９．９９％以上の高純度のものが好ましいが、これに限定されるものではなく、電解コンデンサ電極材料として使用されるものであれば良い。
【００１８】
【実施例】
次に、この発明の電解コンデンサ電極用アルミニウム箔の具体的実施例について説明する。
【００１９】
箔の製造に際しては、表１の全ての箔について純度９９．９９％の高純度アルミニウム鋳塊を面削後、熱間圧延、冷間圧延、中間焼鈍を経て厚さ１００μｍ箔圧延したものを供試材とした。そして、比較例２２を除く箔に対して、後述の凹み付与処理を行い、その後５５０℃×２時間の最終焼鈍を行った。比較例２２は最終焼鈍のみを行った。
【００２０】
前記凹み付与処理は、凹みの形態を変えるために、＃１００〜＃２０００の粒子を用い条件を変えてブラスト処理を行った後、６０℃の８％塩酸＋０．５％硫酸の混合浴中で、周波数１０〜３００Ｈｚ、電流密度１Ａ／ｃｍ２、エッチング電気量：５クーロン／ｃｍ ２ 以下の範囲で条件を変えて交流電解エッチングを行うことにより行った。
【００２１】
最終焼鈍後の箔について、表面からの直接観察とレプリカ法による裏面観察とにより、それぞれ５０００倍に拡大して凹みの形態を観察した。箔表面の一次凹みおよび一次凹み内部の二次凹みの形態について観察結果を表１に示す。
【００２２】
次に、各箔に対し、５％塩酸＋１０％硫酸の混合浴を用いて、７５℃、０．２Ａ／ｃｍ2で１００秒間電解エッチングした後、同液中で１０分間ケミカルエッチングを施した。次いで、５％ホウ酸浴中で３５０Ｖで化成処理を行った後静電容量を測定した。凹み付与処理を行わなかった No.２２の静電容量を１００％として、各箔の相対的な静電容量を表１に併せて示す。
【００２３】
【表１】
表１の結果から、箔表面にの所定の一次凹み、あるいはさらに二次凹みを形成することにより、拡面率を増大させて高い静電容量が得られることを確認できた。
【００２５】
【発明の効果】
以上説明したように、この発明の各電解コンデンサ電極用アルミニウム箔は、表面に円相当径の開口径（ｄ1）が０．１〜５μｍの一次凹みが多数形成されている。そして、前記一次凹みのうち、開口径（ｄ1）／最大内部径（ｄ2）が０．９未満であるという条件を満たすものの数、あるいはその内部に開口する二次凹みを１個以上有し、かつ前記二次凹みの少なくとも１個の開口径（ｄ3）が前記一次凹みの開口径（ｄ1）の１／２以下であるという条件を満たすもの数、あるいはさらにどちらか一方の条件を満たすものの合計数がそれぞれ２０％以上存在するものであるから、エッチングにおいて深いエッチピットの均一高密度発生が促進されて、拡面率が増大して静電容量の増大を図ることができる。
【００２６】
また、各条件を満たす一次凹みの平均深さが０．２μｍ以上であるとともに、存在密度が７×１０4個／mm2以上である箔においては、前記効果が顕著である。
【図面の簡単な説明】
【図１】この発明の電解コンデンサ電極用アルミニウム箔の一例を示す断面図である。
【図２】図１の要部拡大である。
【図３】この発明の電解コンデンサ電極用アルミニウム箔の他の例を示す要部断面図である。
【符号の説明】
１…一次凹み
２…二次凹み
ｄ1…一次凹みの開口径
ｄ2…一次凹みの最大内部径
ｄ3…二次凹みの開口径[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an aluminum foil used as an electrode of an electrolytic capacitor.
[0002]
In this specification, the term “aluminum” is used to include both aluminum and its alloys.
[0003]
[Prior art]
In recent years, with the miniaturization of electronic devices, there has been a demand for improvement in electrostatic capacity of aluminum foil for electrolytic capacitor electrodes incorporated in electronic devices.
[0004]
Usually, an aluminum material used for an electrolytic capacitor electrode is etched in order to increase the surface expansion ratio and improve the capacitance. Since the surface expansion ratio increases as the depth of the etching pit formed by the etching process increases, various processes are performed on the aluminum material as a pre-process of the etching process in order to improve the etching suitability. For example, adjustment of (100) crystal orientation, adjustment of composition by adding trace impurities such as Pb and Bi to aluminum material, degreasing cleaning before final annealing, hydration treatment before final annealing and crystalline oxide film in final annealing Forming treatment, oxidation treatment before final annealing, etc. (Japanese Patent Publication No. 58-34925, Japanese Patent Laid-Open No. 3-122260, etc.).
[0005]
Also, simply increasing the depth of each etching pit is not enough to improve the surface expansion rate of the aluminum foil, and in order to further improve the surface expansion rate, local etching, unetched, surface dissolution is reduced, It is necessary to generate etching pits uniformly and densely on the etching surface. The various methods as described above are not sufficient in that the etching pits are uniformly generated.
[0006]
In view of this, the present applicant proposed in Japanese Patent Laid-Open No. 6-145922 a technique for improving the surface expansion ratio by etching by providing fine projections as etch pit nuclei on the foil surface. Japanese Patent Application Laid-Open No. 6-310384 proposes a technique in which a dent is provided on the foil surface and this is used as a nucleus for generating an etch pit. Summary of the 81st Autumn Meeting of the Japan Institute of Light Metals (November 1991) On page 75, the relationship between the roughening (indentation) of the semispherical or semicubic surface of the aluminum foil surface and the etching property is described.
[0007]
[Problems to be solved by the invention]
However, simply adding protrusions or dents to the foil surface cannot meet the increasing demand for higher capacitance.
[0008]
In view of such a technical background, an object of the present invention is to provide an aluminum foil for an electrolytic capacitor electrode capable of uniformly generating deep etching pits to reliably increase the surface area and further increase the capacitance. It is what.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the first aluminum foil for electrolytic capacitor electrodes of the present invention has a large number of primary recesses (1) having an equivalent circle diameter (d 1 ) of 0.1 to 5 μm on the surface. An aluminum foil having a maximum inner diameter (d 2 ) larger than the opening diameter (d 1 ) of the primary dent (1), and the inside diameter of the inner swelled, and the opening diameter (d 1 ) / maximum The basic gist is that there are 20% or more of those satisfying the condition that the inner diameter (d 2 ) is less than 0.9.
[0010]
The second aluminum foil for electrolytic capacitor electrodes is an aluminum foil having a number of primary recesses (1) having an opening diameter (d 1 ) of equivalent circle diameter of 0.1 to 5 μm formed on the surface thereof. Among the dents (1), the dent (1) has one or more secondary dents (2), and at least one opening diameter (d 3 ) of the secondary dent (2) is the primary dent (1). The basic gist is that there are at least 20% satisfying the condition that it is 1/2 or less of the opening diameter (d 1 ).
[0011]
The third aluminum foil for an electrolytic capacitor electrode is an aluminum foil having a plurality of primary recesses (1) having an equivalent circle diameter (d 1 ) of 0.1 to 5 μm formed on the surface thereof. Of the recesses (1), the maximum inner diameter (d 2 ) is larger than the opening diameter (d 1 ) and the inside swells, and the opening diameter (d 1 ) / maximum inner diameter (d 2 ) is 0. One satisfying the condition that it is less than 9, and having one or more secondary dents (2) opening therein, and at least one opening diameter (d 3 ) of the secondary dent (2) is The basic gist is that there is a total number of 20% or more that satisfies the condition that it is ½ or less of the opening diameter (d 1 ) of the primary dent (1).
[0012]
As shown in FIGS. 1 to 3, the three types of aluminum foils for electrolytic capacitor electrodes of the present invention have a large number of primary recesses (1) that are open on the foil surface and serve as etch pit generation nuclei. Then, by defining the opening diameter (d 1 ) and defining the detailed form, it is possible to form deep pits uniformly and with high density and to reliably improve the surface expansion ratio.
[0013]
In all three types of foils of the present invention, the opening diameter (d 1 ) of the primary dent (1) is defined as an equivalent circle diameter of 0.1 to 5 μm. When the opening diameter (d 1 ) is smaller than 0.1 μm, it is difficult to form etch pit nuclei, and when it exceeds 5 μm, the pits become coarse and the surface expansion rate decreases. The preferable lower limit value of the opening diameter (d 1 ) of the primary recess (1) is 0.2 μm, and the upper limit value is 3 μm.
[0014]
The first aluminum foil for electrolytic capacitor electrodes has the maximum internal diameter (d 2 ) of the primary recess (1) after the opening diameter (d 1 ) of the primary recess (1) is defined within the above range. 20% of the total number satisfying the condition that the inside is larger than the opening diameter (d 1 ) and the inside is swollen and the opening diameter (d 1 ) / maximum internal diameter (d 2 ) is less than 0.9 The presence of the above promotes the generation of deep etch pits by expanding the inside of the primary recess (1). A preferable upper limit value of the opening diameter (d 1 ) / maximum internal diameter (d 2 ) is 0.8, and the number of primary recesses (1) satisfying the above condition is preferably 40% or more. As shown in FIG. 3, the aluminum foil for capacitor electrodes is formed by forming one or more secondary dents (2) opened in the primary dent (1) inside the primary dent (1). The surface area in the primary recess (1) is enlarged to promote uniform and high density generation of deep etch pits. A primary indentation (1) having a secondary indentation (2) in which the opening diameter (d 3 ) of at least one secondary indentation (2) is ½ or less of the opening diameter (d 1 ) of the primary indentation (1) ) To be present in an amount of 20% or more of the total number, the expansion of the surface area of the primary dent (1) is assured. A preferable upper limit value of the opening diameter (d 3 ) of the secondary recess (2) is 1/3 or less of the opening diameter (d 1 ) of the primary recess (1), and has such a secondary recess (2). In the third aluminum foil for electrolytic capacitor electrodes, preferably, the number of primary recesses (1) is 40% or more, the opening diameter (d 1 ) of the primary recess (1) is defined in the above range, It is defined under the conditions of both the opening diameter (d 1 ) / maximum internal diameter (d 2 ) of the primary recess (1) and the opening diameter (d 3 ) of the secondary recess (2), By making the total number of primary recesses (1) satisfying one condition 20% or more, the uniform and high density generation of deep etch pits is promoted.
[0015]
Furthermore, these three types of aluminum foils for electrolytic capacitor electrodes shall have an average depth of 0.2 μm or more of primary dents (1) satisfying the respective conditions and a density of 7 × 10 4 pieces / mm 2 or more. Thus, the surface area of the primary dent (1) is reliably increased, and as a result, the increase of the surface expansion ratio and the increase of the capacitance are ensured by etching. The preferred average depth of the primary dent (1) is 0.5 μm or more, and the preferred density is 8 × 10 4 pieces / mm 2 or more.
[0016]
The primary indentation (1) and secondary indentation (2) in the shape described above are in the normal foil manufacturing process of aluminum ingot chamfering, hot rolling, cold rolling including intermediate annealing, foil rolling, and final annealing. It forms by giving the process which provides a dent before final annealing after foil rolling. Examples of the dent imparting treatment include a method of performing an electrolytic etching treatment after the blasting treatment, a method of sandwiching a foil between two rolls having fine protrusions, transferring the dent, and then roughening by chemical treatment.
[0017]
Further, the aluminum used as the foil material is preferably a high-purity aluminum having a purity of 99.99% or more, but is not limited to this, and any aluminum may be used as long as it is used as an electrolytic capacitor electrode material.
[0018]
【Example】
Next, specific examples of the aluminum foil for electrolytic capacitor electrodes according to the present invention will be described.
[0019]
When manufacturing the foil, all the foils in Table 1 were subjected to face milling of a high-purity aluminum ingot with a purity of 99.99%, followed by hot rolling, cold rolling, and intermediate annealing, and then rolling the foil 100 μm in thickness. Samples were used. And the foil except the comparative example 22 performed the below-mentioned dent provision process, and the final annealing of 550 degreeC x 2 hours was performed after that. In Comparative Example 22, only the final annealing was performed.
[0020]
In order to change the shape of the dent, the dent imparting treatment is performed in a mixed bath of 8% hydrochloric acid + 0.5% sulfuric acid at 60 ° C. after performing blasting using particles of # 100 to # 2000 under different conditions. The frequency was 10 to 300 Hz, the current density was 1 A / cm 2 , the amount of etching electricity was changed by changing the conditions in the range of 5 coulombs / cm 2 or less , and performing AC electrolytic etching.
[0021]
About the foil after final annealing, the form of the dent was observed by enlarging 5000 times by direct observation from the front surface and back surface observation by the replica method. Table 1 shows the observation results of the form of the primary dent on the foil surface and the secondary dent inside the primary dent.
[0022]
Next, each foil was subjected to electrolytic etching at 75 ° C. and 0.2 A / cm 2 for 100 seconds using a mixed bath of 5% hydrochloric acid + 10% sulfuric acid, and then subjected to chemical etching in the same solution for 10 minutes. Next, after performing chemical conversion treatment at 350 V in a 5% boric acid bath, the capacitance was measured. Table 1 shows the relative electrostatic capacity of each foil, assuming that the electrostatic capacity of No. 22 where the dent imparting treatment was not performed is 100%.
[0023]
[Table 1]
From the results in Table 1, it was confirmed that by forming a predetermined primary dent or further secondary dent on the foil surface, the surface expansion ratio was increased and a high capacitance was obtained.
[0025]
【The invention's effect】
As described above, each aluminum foil for electrolytic capacitor electrodes according to the present invention has a large number of primary recesses having an equivalent circle diameter (d 1 ) of 0.1 to 5 μm on the surface. And among the primary recesses, the number of those satisfying the condition that the opening diameter (d 1 ) / maximum internal diameter (d 2 ) is less than 0.9, or one or more secondary recesses open in the interior. And the number satisfying the condition that at least one opening diameter (d 3 ) of the secondary recess is ½ or less of the opening diameter (d 1 ) of the primary recess, or one of the conditions Since the total number of those satisfying the condition is 20% or more, the uniform high-density generation of deep etch pits is promoted in the etching, and the surface expansion ratio can be increased to increase the capacitance.
[0026]
In addition, the above-mentioned effect is remarkable in the foil in which the average depth of the primary dent satisfying each condition is 0.2 μm or more and the existence density is 7 × 10 4 pieces / mm 2 or more.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of an aluminum foil for electrolytic capacitor electrodes according to the present invention.
FIG. 2 is an enlarged view of a main part of FIG.
FIG. 3 is a cross-sectional view of a main part showing another example of the aluminum foil for electrolytic capacitor electrodes according to the present invention.
[Explanation of symbols]
1 ...
Claims (5)
前記一次凹み（１）のうち、その最大内部径（ｄ２）が前記開口径（ｄ１）よりも大きく内部が膨らんだ形状で、開口径（ｄ１）／最大内部径（ｄ２）が０．９未満であるという条件を満たすものの数が２０％以上存在することを特徴とする電解コンデンサ電極用アルミニウム箔。An aluminum foil in which a large number of primary dents (1) having an opening diameter (d 1 ) of a circle-equivalent diameter of 0.1 to 5 μm are formed on the surface,
Of the primary recesses (1), the maximum inner diameter (d 2 ) is larger than the opening diameter (d 1 ) and the inside is swollen, and the opening diameter (d 1 ) / maximum inner diameter (d 2 ) is An aluminum foil for electrolytic capacitor electrodes, characterized in that the number of those satisfying the condition of less than 0.9 is 20% or more.
前記一次凹み（１）のうち、その内部に開口する二次凹み（２）を１個以上有し、かつ前記二次凹み（２）の少なくとも１個の開口径（ｄ３）が前記一次凹み（１）の開口径（ｄ１）の１／２以下であるという条件を満たすものの数が２０％以上存在することを特徴とする電解コンデンサ電極用アルミニウム箔。An aluminum foil in which a large number of primary dents (1) having an opening diameter (d 1 ) of a circle-equivalent diameter of 0.1 to 5 μm are formed on the surface,
Among the primary recesses (1), the primary recess (1) has one or more secondary recesses (2), and at least one opening diameter (d 3 ) of the secondary recess (2) is the primary recess. An aluminum foil for electrolytic capacitor electrodes, characterized in that the number of those satisfying the condition that the opening diameter (d 1 ) of ( 1 ) is ½ or less is 20% or more.
前記一次凹み（１）のうち、その最大内部径（ｄ ２ ）が前記開口径（ｄ １ ）よりも大きく内部が膨らんだ形状で、開口径（ｄ １ ）／最大内部径（ｄ ２ ）が０．９未満であるという条件を満たすものと、その内部に開口する二次凹み（２）を１個以上有し、かつ前記二次凹み（２）の少なくとも１個の開口径（ｄ ３ ）が前記一次凹み（１）の開口径（ｄ １ ）の１／２以下であるという条件を満たすものとが合計数で２０％以上存在し、
前記のいずれかの条件を満たす一次凹み（１）は、平均深さが０．２μｍ以上でありかつ７×１０４個／mm２以上の密度で存在することを特徴とする電解コンデンサ電極用アルミニウム箔。 An aluminum foil in which a large number of primary dents (1) having an opening diameter (d 1 ) of a circle-equivalent diameter of 0.1 to 5 μm are formed on the surface,
Of the primary recesses (1), the maximum inner diameter (d 2 ) is larger than the opening diameter (d 1 ) and the inside is swollen, and the opening diameter (d 1 ) / maximum inner diameter (d 2 ) is One satisfying the condition that it is less than 0.9, and having at least one secondary recess (2) opening therein, and at least one opening diameter (d 3 ) of the secondary recess (2 ) That satisfy the condition that is less than or equal to ½ of the opening diameter (d 1 ) of the primary recess (1) ,
Wherein any of the conditions are satisfied primary recesses (1) is an aluminum electrolytic capacitor electrodes, characterized in that the average depth is present at least at and and 7 × 10 4 cells / mm 2 or more densities 0.2μm Foil.
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| JP32673899A JP4452355B2 (en) | 1999-11-17 | 1999-11-17 | Aluminum foil for electrolytic capacitor electrode |
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| CN100530463C (en) * | 2003-06-03 | 2009-08-19 | 昭和电工株式会社 | Method for producing aluminum material for electrolytic capacitor electrode |
| JPWO2018051520A1 (en) * | 2016-09-16 | 2019-07-11 | 日本蓄電器工業株式会社 | Electrode member for electrolytic capacitor and electrolytic capacitor |
| CN109716469B (en) | 2016-09-16 | 2021-06-04 | 日本蓄电器工业株式会社 | Electrode parts for electrolytic capacitors and electrolytic capacitors |
| CN112106159B (en) * | 2018-06-11 | 2023-02-28 | 日本贵弥功株式会社 | Electrode body, electrolytic capacitor provided with electrode body, and method for manufacturing electrode body |
| JP7028481B2 (en) * | 2020-12-28 | 2022-03-02 | 日本蓄電器工業株式会社 | Electrode members for electrolytic capacitors and electrolytic capacitors |
| US12525407B2 (en) * | 2021-01-29 | 2026-01-13 | Panasonic Intellectual Property Management Co., Ltd. | Electrode foil for electrolytic capacitors, and electrolytic capacitor |
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