JP3920301B2 - Aluminum foil for electrolytic capacitors - Google Patents
Aluminum foil for electrolytic capacitors Download PDFInfo
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- JP3920301B2 JP3920301B2 JP2005307334A JP2005307334A JP3920301B2 JP 3920301 B2 JP3920301 B2 JP 3920301B2 JP 2005307334 A JP2005307334 A JP 2005307334A JP 2005307334 A JP2005307334 A JP 2005307334A JP 3920301 B2 JP3920301 B2 JP 3920301B2
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- 239000011888 foil Substances 0.000 title claims description 42
- 229910052782 aluminium Inorganic materials 0.000 title claims description 41
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 title claims description 40
- 239000003990 capacitor Substances 0.000 title claims description 15
- 238000005530 etching Methods 0.000 claims description 35
- 239000000654 additive Substances 0.000 claims description 12
- 230000000996 additive effect Effects 0.000 claims description 12
- 239000012535 impurity Substances 0.000 claims description 5
- 229910052737 gold Inorganic materials 0.000 claims description 4
- 229910052748 manganese Inorganic materials 0.000 claims description 4
- 229910052759 nickel Inorganic materials 0.000 claims description 4
- 229910052697 platinum Inorganic materials 0.000 claims description 4
- 229910052709 silver Inorganic materials 0.000 claims description 4
- 229910052718 tin Inorganic materials 0.000 claims description 4
- 239000002344 surface layer Substances 0.000 description 12
- 238000000034 method Methods 0.000 description 10
- 239000000126 substance Substances 0.000 description 10
- 238000000137 annealing Methods 0.000 description 9
- 230000008569 process Effects 0.000 description 9
- 238000005097 cold rolling Methods 0.000 description 7
- 238000004090 dissolution Methods 0.000 description 7
- 239000000243 solution Substances 0.000 description 7
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 6
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 6
- 239000013078 crystal Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 238000007788 roughening Methods 0.000 description 6
- 238000010438 heat treatment Methods 0.000 description 5
- 239000002253 acid Substances 0.000 description 4
- 230000005611 electricity Effects 0.000 description 4
- 238000000866 electrolytic etching Methods 0.000 description 4
- 238000005098 hot rolling Methods 0.000 description 4
- 229910052742 iron Inorganic materials 0.000 description 4
- 238000004833 X-ray photoelectron spectroscopy Methods 0.000 description 3
- 238000009749 continuous casting Methods 0.000 description 3
- 238000007796 conventional method Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000008151 electrolyte solution Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 229910000838 Al alloy Inorganic materials 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000012141 concentrate Substances 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 230000009257 reactivity Effects 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 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
- 239000010406 cathode material Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000005238 degreasing Methods 0.000 description 1
- 238000005868 electrolysis reaction Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 238000002161 passivation Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
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Description
この発明は、電解コンデンサの電極に用いられる電解コンデンサ電極用アルミニウム箔に関するものである。 The present invention relates to an aluminum foil for electrolytic capacitor electrodes used for electrodes of electrolytic capacitors.
従来、電解コンデンサ用エッチング箔は、９９．９％以上のアルミニウム純度で、Ｓｉ：５〜２０ｐｐｍ、Ｆｅ：５〜２０ｐｐｍ、Ｃｕ：１０〜８０ｐｐｍ、Ｐｂ：０．１〜３ｐｐｍ、その他微量不純物１〜１００ｐｐｍで構成され、熱間圧延、冷間圧延、中間焼鈍、付加圧延を経て、５００℃以上、３時間以上の焼鈍を行って９５％以上の立方晶率が得られたアルミニウム箔として製造されている。
該アルミニウム箔は、さらに、強酸溶液中で電解エッチングを行い腐食孔（以降ピット）を発生させた後、酸溶液中で、電解又は化学溶解により、ピット径を次工程の化成における電圧に応じた大きさに拡大している。
高純度アルミニウム箔の特徴として、酸溶液中では不動態化が進行するため、化学溶解性が低く、このため、電解エッチングが不可欠であると考えられている。電解エッチングにて必要なピット数を得るためには、４０〜６０Ｃ／ｃｍ２の電気量が必要となり、これを得るために大量の電気を消費している。
上記した電気量の低減に対しては、アルミニウム箔のエッチング性を向上させることが有効である。例えば特許文献１では、各種元素を酸化皮膜表面、又は、酸化皮膜と箔基体界面に配置することが提案されている。該特許文献１において、箔表面に配置された元素は、エッチングピットの基点として作用するため、極表層部に配置することが重要であると指摘されている。
The aluminum foil is further subjected to electrolytic etching in a strong acid solution to generate corrosion holes (hereinafter referred to as pits), and then the electrolytic solution or chemical dissolution in the acid solution is used to adjust the pit diameter according to the voltage in the formation of the next step. It has expanded to size.
As a feature of high-purity aluminum foil, since passivation proceeds in an acid solution, chemical solubility is low, and therefore, electrolytic etching is considered indispensable. In order to obtain the required number of pits by electrolytic etching, an amount of electricity of 40 to 60 C / cm 2 is required, and a large amount of electricity is consumed to obtain this.
For reducing the amount of electricity described above, it is effective to improve the etching property of the aluminum foil. For example,
通常、エッチング反応の進行に伴い、アルミニウム箔表面の欠落が生じ、表層の０．１〜０．５μｍは除去される。したがって、特許文献１に示されるように極表層部に配置された元素は、その初期段階における反応性には寄与できるが、エッチング反応全般にわたって寄与することができない。
また、アルミニウム箔の純度を９９％程度に低下させた場合、アルミニウム箔中の不純物元素により、化学溶解性が促進される。しかし、アルミニウム純度の低下により、結晶方位の均一性がなくなり、エッチングピットの成長が一方向でなくなるため、表面溶解のみ進行し、正常なエッチングピットが得られない。立方晶率を９５％に保つためには、９９．９％以上のアルミニウム純度が必要であり、アルミニウム純度によって化学溶解性を調整することは困難である。
Usually, with the progress of the etching reaction, the aluminum foil surface is missing, and 0.1 to 0.5 μm of the surface layer is removed. Therefore, although the element arrange | positioned at the extreme surface layer part as shown by
Further, when the purity of the aluminum foil is lowered to about 99%, chemical solubility is promoted by the impurity element in the aluminum foil. However, due to the decrease in aluminum purity, the uniformity of crystal orientation is lost and the growth of etching pits is no longer unidirectional, so that only surface dissolution proceeds and normal etching pits cannot be obtained. In order to keep the cubic rate at 95%, an aluminum purity of 99.9% or more is necessary, and it is difficult to adjust the chemical solubility by the aluminum purity.
本発明は、上記事情を背景としてなされたものであり、高純度アルミニウム箔の化学反応性を著しく高め、電気を使用することなくピット発生が可能な箔を提供することにより、エッチングにおける、コストダウン、生産性向上を目的とするものである。 The present invention has been made against the background of the above circumstances, and significantly reduces the chemical reactivity of high-purity aluminum foil, and provides a foil capable of generating pits without using electricity, thereby reducing costs in etching. The purpose is to improve productivity.
本発明の目的である、化学溶解を主体としたエッチングピット発生においては、アルミニウム箔表面で生じた化学反応が、継続的に進行することが必要であり、そのためには、元素の濃度勾配が、箔内部、少なくとも０．５μｍ深さまでは継続する必要がある。そして、特定の元素を、アルミニウム純度を低下させない量、すなわち１０００ｐｐｍ以下含有させ、熱処理によってアルミニウム箔表面に濃化できることを見いだし、本発明を完成するに至ったものである。 In the generation of etching pits mainly composed of chemical dissolution, which is the object of the present invention, it is necessary that the chemical reaction generated on the surface of the aluminum foil proceeds continuously. It is necessary to continue at least 0.5 μm deep inside the foil. The inventors have found that a specific element is contained in an amount that does not decrease the aluminum purity, that is, 1000 ppm or less, and can be concentrated on the surface of the aluminum foil by heat treatment, and the present invention has been completed.
すなわち、本発明の電解コンデンサ用アルミニウム箔の発明は、エッチングに供される電解コンデンサ用アルミニウム箔であって、質量比で、Ｓｉ：５〜４０ｐｐｍ、Ｆｅ：５〜４０ｐｐｍ、Ｐｂ：０．１〜３ｐｐｍ含有し、かつ、Ｍｎ、Ｎｉ、Ｓｎ、Ａｇ、Ｐｔ、Ａｕから選ばれる元素のうち、一種、又は二種以上を添加元素として総量で２０〜２００ｐｐｍ含有し、残部が９９．９％以上のＡｌと不可避不純物からなる組成を有し、酸化皮膜厚が２０〜６０Åであり、前記アルミニウム箔の１μｍ深さ位置における前記添加元素のイオン強度を１として、０．１μｍ深さでのイオン強度比が１０以上、０．３μｍ深さでのイオン強度比が２以上、０．５μｍ深さでのイオン強度比が１．５以上である濃度勾配を有することを特徴とする。 That is, the invention of the aluminum foil for electrolytic capacitors of the present invention is an aluminum foil for electrolytic capacitors to be used for etching, and in terms of mass ratio, Si: 5 to 40 ppm, Fe: 5 to 40 ppm, Pb: 0.1 It contains 3 ppm, and among elements selected from Mn, Ni, Sn, Ag, Pt, and Au, one or two or more elements are added as additive elements in a total amount of 20 to 200 ppm, and the balance is 99.9% or more An ionic strength ratio at a depth of 0.1 μm having a composition comprising Al and inevitable impurities, an oxide film thickness of 20 to 60 mm, and an ionic strength of the additive element at a depth of 1 μm of the aluminum foil as 1. Has a concentration gradient in which the ion intensity ratio at a depth of 10 or more and 0.3 μm is 2 or more and the ion intensity ratio at a depth of 0.5 μm is 1.5 or more.
以下に、本発明の各成分による作用および各成分を限定した理由を説明する。なお、以下における成分含有量はいずれも質量比である。 Below, the effect | action by each component of this invention and the reason which limited each component are demonstrated. In addition, all the component content in the following is mass ratio.
Ｓｉ：５〜４０ｐｐｍ、Ｆｅ：５〜４０ｐｐｍ
Ｓｉ、ＦｅはＡｌと化合し適度に析出物を生成し、再結晶粒の粗大化を抑制するし、Ｃｕｂｅ粒の優先成長を促進することができる。ただし、各々、５ｐｐｍ未満の場合精製コストが高くなり、工業的には不向きである。一方、各々４０ｐｐｍ超の場合、析出物の総量が多くなりすぎてＣｕｂｅ粒の優先成長まで制御するため、高い立方晶率が得られなくなる。このため、Ｓｉ、Ｆｅの含有量を上記範囲に定める。なお、望ましい下限は、Ｓｉ、Ｆｅともに１０ｐｐｍであり、望ましい上限はＳｉ、Ｆｅともに２０ｐｐｍである。
Si: 5 to 40 ppm, Fe: 5 to 40 ppm
Si and Fe combine with Al to appropriately generate precipitates, suppress coarsening of recrystallized grains, and promote preferential growth of Cube grains. However, if it is less than 5 ppm, the purification cost becomes high, which is unsuitable industrially. On the other hand, in the case where each exceeds 40 ppm, the total amount of precipitates becomes too large to control the preferential growth of Cube grains, so that a high cubic crystal ratio cannot be obtained. For this reason, the content of Si and Fe is set within the above range. A desirable lower limit is 10 ppm for both Si and Fe, and a desirable upper limit is 20 ppm for both Si and Fe.
Ｐｂ：０．１〜３ｐｐｍ
Ｐｂはエッチングにおける表面溶解を均一にする元素である。ただし、０．１ｐｐｍ未満ではその効果が期待できず、３ｐｐｍ超では溶解性が高くなりすぎて過剰溶解を起こす。したがって、Ｐｂの含有量を上記に定める。なお、望ましい下限は、０．２ｐｐｍであり、望ましい上限は１ｐｐｍである。
Pb: 0.1 to 3 ppm
Pb is an element that makes surface dissolution uniform in etching. However, if it is less than 0.1 ppm, the effect cannot be expected, and if it exceeds 3 ppm, the solubility becomes too high and excessive dissolution occurs. Therefore, the content of Pb is defined above. A desirable lower limit is 0.2 ppm, and a desirable upper limit is 1 ppm.
Ｍｎ、Ｎｉ、Ｓｎ、Ａｇ、Ｐｔ、Ａｕの一種、又は二種以上：総量２０〜２００ｐｐｍ
これら添加元素とバルクのアルミニウムとは局部電池反応を起こすため、無電解においてもピット生成が可能になる。箔表層よりエッチングピットを発生させるためには、これらの物質を適量、具体的には総量で２０〜２００ｐｐｍ含有させて、熱処理によってアルミ箔表面に濃縮させる必要がある。総量が２０ｐｐｍ未満であると、上記作用が十分に得られず、無電解でのエッチングが困難になる。一方、２００ｐｐｍを超えて含有すると、ピット生成が過度になりピットの結合などによって却ってピット生成効率が悪くなる。なお、同様の理由で下限を５０ｐｐｍ、上限を１８０ｐｐｍとするのが望ましい。
One or more of Mn, Ni, Sn, Ag, Pt, Au:
Since these additive elements and bulk aluminum cause a local battery reaction, pits can be generated even without electrolysis. In order to generate etching pits from the foil surface layer, it is necessary to contain an appropriate amount of these substances, specifically 20 to 200 ppm in total, and to concentrate on the aluminum foil surface by heat treatment. When the total amount is less than 20 ppm, the above-mentioned effect cannot be obtained sufficiently, and electroless etching becomes difficult. On the other hand, if the content exceeds 200 ppm, the pit generation becomes excessive and the pit generation efficiency deteriorates due to the pit coupling. For the same reason, it is desirable to set the lower limit to 50 ppm and the upper limit to 180 ppm.
酸化皮膜厚さ（２０〜６０Å）
エッチング処理に供される直前のアルミニウム箔では、表面に適度な厚さの酸化皮膜が形成されていることが必要である。この酸化皮膜厚さが２０Å未満になると、表面溶解過多による粗面化率の低下が生じ、６０Åを超えると局部的な溶解形態になり粗面化率の低下となるので、２０〜６０Åの範囲を設定する。酸化皮膜厚さは、例えば、Ｘ線光電子分析（ＥＳＣＡ）によって測定することができる。なお、測定装置構成、測定手順は本発明としては特に限定されるものではなく、常法により行うことができる。
Oxide film thickness (20-60mm)
In the aluminum foil immediately before being subjected to the etching treatment, it is necessary that an oxide film having an appropriate thickness is formed on the surface. When the thickness of the oxide film is less than 20 mm, the roughening rate is reduced due to excessive surface dissolution. When the thickness exceeds 60 mm, the surface is dissolved locally and the roughening rate is decreased. Set. The oxide film thickness can be measured by, for example, X-ray photoelectron analysis (ESCA). In addition, a measuring apparatus structure and a measurement procedure are not specifically limited as this invention, It can carry out by a conventional method.
イオン強度比：
０．１μｍ深さ：１０以上、０．３μｍ深さ：２以上、０．５μｍ深さ：１．５以上
上記添加元素が表層部で濃縮されており、かつ上記の濃度勾配を有しているのが望ましい。より表面側が高い濃度を有することによってピット生成が効果的に促進され、また、深さ方向にピットが効果的に成長して粗面化率を向上させる。なお、上記添加元素が二種以上の場合、総量で上記イオン強度比を満していればよい。
Ion intensity ratio:
0.1 μm depth: 10 or more, 0.3 μm depth: 2 or more, 0.5 μm depth: 1.5 or more The additive element is concentrated in the surface layer portion and has the concentration gradient described above. Is desirable. By having a higher concentration on the surface side, pit generation is effectively promoted, and pits are effectively grown in the depth direction to improve the roughening rate. In addition, when the said additional element is 2 or more types, the said ionic strength ratio should just be satisfy | filled with the total amount.
アルミニウム純度：９９．９％以上
純度９９．９％未満であると、結晶方位の均一性がなくなり、正常なエッチングピットが得られない。結晶方位の均一性を確保して立方晶率を９５％以上に保つためには、９９．９％以上のアルミニウム純度が必要である。
Aluminum purity: 99.9% or more If the purity is less than 99.9%, the uniformity of crystal orientation is lost and normal etching pits cannot be obtained. An aluminum purity of 99.9% or more is necessary to ensure the uniformity of crystal orientation and keep the cubic ratio at 95% or more.
以上説明したように、本発明の電解コンデンサ用アルミニウム箔は、エッチングに供される電解コンデンサ用アルミニウム箔であって、質量比で、Ｓｉ：５〜４０ｐｐｍ、Ｆｅ：５〜４０ｐｐｍ、Ｐｂ：０．１〜３ｐｐｍ含有し、かつ、Ｍｎ、Ｎｉ、Ｓｎ、Ａｇ、Ｐｔ、Ａｕから選ばれる元素のうち、一種、又は二種以上を添加元素として総量で２０〜２００ｐｐｍ含有し、残部が９９．９％以上のＡｌと不可避不純物からなる組成を有し、酸化皮膜厚が２０〜６０Åであり、前記アルミニウム箔の１μｍ深さ位置における前記添加元素のイオン強度を１として、表面から０．５μｍ深さでのイオン強度比が１．５以上であり、０．１μｍ深さでのイオン強度比が１０以上、０．３μｍ深さでのイオン強度比が２以上であるので、無電解エッチングにおいてもピットが効率的に生成され、良好な粗面化率を得ることが可能になる。これにより電解コンデンサ製造に際し、コストダウン、生産性向上が可能になる。 As explained above, the aluminum foil for electrolytic capacitors of the present invention is an aluminum foil for electrolytic capacitors to be used for etching, and has a mass ratio of Si: 5 to 40 ppm, Fe: 5 to 40 ppm, Pb: 0.00. 1 to 3 ppm, and among elements selected from Mn, Ni, Sn, Ag, Pt, and Au, one or more elements are added as additive elements, and the total content is 20 to 200 ppm, the balance being 99.9% It has a composition comprising the above Al and inevitable impurities, has an oxide film thickness of 20 to 60 mm, and has an ionic strength of the additive element at a depth of 1 μm of the aluminum foil as 1 and a depth of 0.5 μm from the surface. The ionic strength ratio is 1.5 or more, the ionic strength ratio at a depth of 0.1 μm is 10 or more, and the ionic strength ratio at a depth of 0.3 μm is 2 or more. Pits in grayed is efficiently generated, it is possible to obtain good roughening rate. This makes it possible to reduce costs and improve productivity when manufacturing electrolytic capacitors.
純度９９．９％以上で本発明の成分となるように調製された高純度アルミニウム材を用意する。該アルミニウム材は、好適には純度９９．９５％以上とする。
該アルミニウム材は常法により得ることができ、本発明としては特にその製造方法が限定されるものではない。例えば、半連続鋳造によって得たスラブを熱間圧延したものを用いることができるし、その他に連続鋳造により得られる高純度アルミニウム材を対象とするものであってもよい。上記熱間圧延または連続鋳造圧延によって例えば数ｍｍ厚程度のシート材とする。このシート材に対し冷間圧延を行い、数十μｍから１００μｍ程度のアルミニウム合金箔を得る。なお、冷間圧延途中あるいは冷間圧延終了後に適宜脱脂を加えてもよく、また冷間圧延の途中で適宜中間焼鈍を加えても差し支えない。
最終冷間圧延後には、最終焼鈍熱処理を行う。最終焼鈍の加熱条件は、前記した添加元素を表層部に濃縮させるために重要であり、例えば、５００〜５８０℃×３〜２４ｈｒ、Ｈ２などを用いた還元性雰囲気または、Ａｒ、Ｎ２等の不活性雰囲気中で加熱することで平均厚さで２０〜６０Åの酸化皮膜を有するアルミニウム合金箔を得ることができる。還元性雰囲気では、Ｈ２などの還元性ガスに不活性ガスや微量の酸素などを混合した混合ガスを用いることも可能である。立方晶率は９５％以上であるのが望ましい。上記焼鈍によって前記添加元素が表層部に濃縮する。なお、焼鈍を真空下で行うと、表面に酸化皮膜が適切に形成されずエッチング時に良好なエッチングが困難になる。
A high-purity aluminum material prepared to be a component of the present invention with a purity of 99.9% or more is prepared. The aluminum material preferably has a purity of 99.95% or more.
The aluminum material can be obtained by a conventional method, and the production method is not particularly limited in the present invention. For example, a hot-rolled slab obtained by semi-continuous casting can be used, or a high-purity aluminum material obtained by continuous casting can be used. For example, a sheet material having a thickness of about several mm is formed by the hot rolling or continuous casting rolling. This sheet material is cold-rolled to obtain an aluminum alloy foil of about several tens of μm to 100 μm. In addition, degreasing may be appropriately added during the cold rolling or after the end of the cold rolling, and intermediate annealing may be appropriately added during the cold rolling.
After the final cold rolling, a final annealing heat treatment is performed. The heating conditions for the final annealing are important for concentrating the above-described additive elements in the surface layer portion. For example, a reducing atmosphere using 500 to 580 ° C. × 3 to 24 hr, H 2 , Ar, N 2 or the like By heating in an inert atmosphere, an aluminum alloy foil having an oxide film with an average thickness of 20 to 60 mm can be obtained. In a reducing atmosphere, a mixed gas obtained by mixing a reducing gas such as H 2 with an inert gas or a small amount of oxygen can be used. It is desirable that the cubic crystal ratio is 95% or more. The said additional element concentrates on a surface layer part by the said annealing. If annealing is performed under vacuum, an oxide film is not properly formed on the surface, and good etching becomes difficult during etching.
上記各工程を経て得られたアルミニウム箔には、その後、エッチング処理がなされる。該エッチング工程は塩酸を主体とする電解液や塩酸を含まない電解液を用いた無電解エッチングにより行うことができる。ただし、本発明としては、電解エッチングを採用するものであってもよく、その場合にも良好な粗面化率が得られる。
エッチング処理は、表層部除去工程と、エッチングピット発生工程と、エッチングピット孔径拡大工程により行うことができる。 表層部除去工程は、酸化皮膜を含む表層部を溶解することによって除去する。表層部除去後は、アルミニウム箔表面にエッチングピットを発生させるエッチングピット発生工程を行う。エッチングピット発生工程後に、エッチングピット孔径拡大工程を行う。
エッチング処理においては、無電解においてもピットが高密度で形成され、高い粗面化率が得られる。この箔を化成処理し、必要な耐圧電を得た後、常法により電解コンデンサに電極として組み込むことにより静電容量の高いコンデンサが得られる。
The aluminum foil obtained through the above steps is then subjected to an etching process. The etching step can be performed by electroless etching using an electrolytic solution mainly composed of hydrochloric acid or an electrolytic solution not containing hydrochloric acid. However, the present invention may employ electrolytic etching, and in that case, a good roughening rate can be obtained.
The etching process can be performed by a surface layer portion removing process, an etching pit generating process, and an etching pit hole diameter expanding process. The surface layer portion removing step is performed by dissolving the surface layer portion including the oxide film. After removing the surface layer portion, an etching pit generation step is performed for generating etching pits on the surface of the aluminum foil. After the etching pit generation process, an etching pit hole diameter expanding process is performed.
In the etching process, pits are formed with high density even in electroless process, and a high roughening rate is obtained. After this foil is subjected to chemical conversion treatment to obtain the necessary piezoelectric resistance, a capacitor having a high capacitance can be obtained by incorporating it as an electrode in an electrolytic capacitor by a conventional method.
本発明は中高圧電解コンデンサの陽極として使用するのが好適であるが、本発明としてはこれに限定されるものではなく、より化成電圧の低いコンデンサ用としても使用することができ、また電解コンデンサの陰極用の材料として使用することもできる。 The present invention is preferably used as an anode of a medium-high voltage electrolytic capacitor. However, the present invention is not limited to this, and can be used for a capacitor having a lower formation voltage. It can also be used as a cathode material.
表に示す成分の鋳塊を作製し、５００℃以上、３０分以上の均熱処理を行った後、加工率９５〜９９％の熱間圧延を行った。その際仕上がり温度は２５０〜４００℃とした。熱間圧延後に９５％以上の冷間圧延を行い箔厚１１０μｍの試料を作成した。冷間圧延の際、必要に応じ中間焼鈍を行った。
これらの箔を、Ａｒ、Ｎ２、Ｈ２等の雰囲気中で表２に示す温度、時間で焼鈍を行い、９５％以上の立方晶率が得られている箔を作製した。焼鈍の際、温度、時間を変更することで、濃縮濃度勾配の異なる試料が得られた。酸化皮膜厚は、ＥＳＣＡ（×線光電子分光法）で測定した。
元素の濃度勾配はＳＩＭＳ（二次イオン質量計測装置）を用い、各深さ位置におけるイオン強度を検出することで求めた。
Ingots having the components shown in the table were prepared and subjected to a soaking treatment at 500 ° C. or higher for 30 minutes or longer, followed by hot rolling at a processing rate of 95 to 99%. At that time, the finishing temperature was 250 to 400 ° C. After hot rolling, cold rolling of 95% or more was performed to prepare a sample having a foil thickness of 110 μm. During cold rolling, intermediate annealing was performed as necessary.
These foils were annealed in an atmosphere of Ar, N 2 , H 2 or the like at the temperatures and times shown in Table 2 to produce foils having a cubic crystal ratio of 95% or more. Samples with different concentration gradients were obtained by changing the temperature and time during annealing. The oxide film thickness was measured by ESCA (x-ray photoelectron spectroscopy).
The concentration gradient of the element was determined by detecting the ion intensity at each depth position using SIMS (secondary ion mass measuring device).
これらのアルミニウム箔を４０℃、３ｍｏｌ／ｌの硫酸溶液に浸漬し酸化皮膜除去を行った。皮膜除去後、水洗を行い、７０℃、１ｍｏｌ／ｌ塩酸＋３ｍｏｌ／ｌ硫酸の混酸溶液に６０ｓｅｃ浸漬しエッチングピットを発生させた。ピット発生後、水洗を行い、７５℃、３ｍｏｌ／ｌ硫酸溶液中に６００ｓｅｃ浸漬し、ピット径の拡大を行った。ピット径拡大後、イオン交換水にて洗浄を行い乾燥した。 These aluminum foils were immersed in a 3 mol / l sulfuric acid solution at 40 ° C. to remove the oxide film. After removing the film, it was washed with water and immersed in a mixed acid solution of 70 ° C., 1 mol / l hydrochloric acid + 3 mol / l sulfuric acid for 60 seconds to generate etching pits. After the pit was generated, it was washed with water and immersed in a 3 mol / l sulfuric acid solution at 75 ° C. for 600 sec to enlarge the pit diameter. After expanding the pit diameter, it was washed with ion-exchanged water and dried.
得られたエッチング箔を１０ｗｔ％のホウ酸溶液で３００Ｖの化成を行い静電容量の評価を行い、実施例１を１００％として相対評価した。 The obtained etching foil was subjected to chemical conversion at 300 V with a 10 wt% boric acid solution to evaluate the capacitance, and relative evaluation was made assuming that Example 1 was 100%.
実施例１〜９の通り、添加元素を加えた箔の場合、化学溶解にてエッチングピットが発生し、高い静電容量が得られていることがわかる。実施例１のイオン強度比の深さ方向での変化を図１に示す。図に示すように。表面から１μｍの深さ位置に対し、０．１μｍ深さでのイオン強度比が１０以上、０．３μｍ深さでのイオン強度比が２以上、０．５μｍ深さでのイオン強度比が１．５以上となり、表層部での添加元素の濃縮が良好になされている。
比較例１の添加元素を加えない場合、エッチングピットが発生しないため、著しく静電容量が低くなる。又、濃度勾配が０．５μｍ深さまで継続して起きていない場合は、エッチングピットは発生するが、その数が不足するため、全般的に低い値となった。
As in Examples 1 to 9, in the case of the foil added with the additive element, it can be seen that etching pits are generated by chemical dissolution and a high capacitance is obtained. The change in the depth direction of the ionic strength ratio of Example 1 is shown in FIG. As shown in the figure. With respect to a depth position of 1 μm from the surface, the ionic strength ratio at a depth of 0.1 μm is 10 or more, the ionic strength ratio at a depth of 0.3 μm is 2 or more, and the ionic strength ratio at a depth of 0.5 μm is 1. The concentration of the additive element in the surface layer is excellent.
When the additive element of Comparative Example 1 is not added, etching pits are not generated, and the electrostatic capacity is remarkably reduced. In addition, when the concentration gradient does not continue to the depth of 0.5 μm, etching pits are generated, but the number is insufficient, so the value is generally low.
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| JP2005307334A JP3920301B2 (en) | 2005-10-21 | 2005-10-21 | Aluminum foil for electrolytic capacitors |
| EP06252838A EP1734546A3 (en) | 2005-06-14 | 2006-06-01 | Aluminum foil for the electrolytic capacitor and etching method for forming etching pits |
| CN2006101357609A CN1921042B (en) | 2005-06-14 | 2006-06-14 | Aluminum foil for the electrolytic capacitor and etching method for forming etching pits |
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