JP2000345271A - Aluminum cladding material and aluminum foil for electrode of electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide aluminum foil for the electrode of an electrolytic capacitor excellent in etching characteristics, capable of realizing high capacitance and moreover excellent in folding endurance and to provide an aluminum cladding material to form into the material of the foil. SOLUTION: This aluminum foil is obtd. by cladding an etching layer 12 on at least one side of a reinforcing layer 11 contg., by weight, >=99.60% Al and moreover contg. Sc and Zr by 10 to <1.000 ppm Sc and 10 to <2,000 ppm Zr also in the ratio satisfying -400 ppm<2Sc-Zr<950 ppm, and the balance impurities. Furthermore, the etching layer 12 is clad via an insert layer 13 checking the growth of etching pits in the foil thickness direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an aluminum clad material and an aluminum foil for an electrode of an electrolytic capacitor.

[0002] In this specification, the term "aluminum" is used to include both aluminum and its alloys.

[0003]

2. Description of the Related Art An aluminum foil used as an electrode material of an aluminum electrolytic capacitor is subjected to an electrochemical or chemical etching treatment in order to increase its effective area and increase the capacitance per unit area. In particular,
Due to the demand for downsizing parts due to product downsizing,
There is a growing need for higher capacitance.

However, if the etching density of the foil is increased,
When the etching layer is made thicker, the bending strength is remarkably reduced, and a problem of foil breakage in the etching line occurs. Further, when a chemical conversion treatment for applying a dielectric film is performed, the bending strength of the foil is remarkably reduced, and breakage occurs in a chemical conversion line or when wound up as an electrolytic capacitor. On the other hand, in recent years, there has been a tendency that Fe and Si in the material are reduced, that is, the purity is increased, in order to improve the etching characteristics for the purpose of improving the capacitance and secure the cubic orientation occupancy rate, that is, to increase the foil strength. Therefore, securing bending strength is an important issue.

In order to solve this problem, conventionally, a foil has a three-layer structure in which outer layers are provided on both sides of a core layer, and growth of etching pits of the outer layer to be etched on the core layer is prevented to reduce the thickness of the core layer. Various methods have been proposed to secure the bending strength by securing the same.

For example, in Japanese Patent Application Laid-Open No. Sho 51-113154, the core layer is made of an aluminum material having a higher Fe content than the outer layer, and the growth of etching pits is caused by the Al-Fe based metal contained in the core layer. It is disclosed to be blocked by a compound. Further, Japanese Patent Application Laid-Open No. Sho 62-47110
Japanese Patent Application Laid-Open Publication No. H11-157, discloses that the growth of etching pits is prevented by forming the core layer from an aluminum material having a lower purity than the outer layer. Further, the present applicant discloses in Japanese Patent Application Laid-Open No. 4-120235 that the core layer is (1)
It has been proposed to prevent the growth of etching pits on the core layer by using an aluminum layer having a crystal plane occupancy of 40% or more other than the (00) plane.

[0007]

However, the above-mentioned method has a problem that a sufficient bending strength cannot be obtained or a sufficient chemical conversion film cannot be formed during chemical conversion due to a coarse intermetallic compound. However, they have not yet been able to sufficiently respond to higher capacitance and improved bending strength.

The present invention has been made in view of such technical background,
An object of the present invention is to provide an aluminum foil for an electrolytic capacitor electrode, which is excellent in etching characteristics and can realize high capacitance and has excellent bending strength, and an aluminum clad material as a material of the foil.

[0009]

In order to achieve the above object, each aluminum clad material of the present invention has a reinforcing layer containing a predetermined amount of Sc and Zr in a predetermined ratio, and further serves as an etching layer. The outer layer and the insert layer are clad.

That is, the aluminum clad material of claim 1 contains at least one layer of at least 99.60 wt% of Al and contains Sc and Zr in an amount of 10 ppm to less than 1000 ppm of Sc and 10 ppm to 2000 ppm of Zr.
pm and -400 ppm <2Sc-Zr <95
It is characterized in that the reinforcing layer is contained in a ratio satisfying 0 ppm and the balance is made of impurities.

The aluminum clad material according to claim 2 contains at least one layer of Al: 99.60 wt% or more, and contains Sc and Zr in an amount of Sc: 10 ppm or more.
0 ppm, Zr: 10 ppm or more and less than 2000 ppm, and -400 ppm <2Sc-Zr <950 pp
m, an aluminum clad material comprising a reinforcing layer composed of impurities and the remainder being clad, and an outer layer clad on at least one surface of the reinforcing layer, wherein the outer layer is made of Al: 99.80 wt. %, Fe: 5 to 60 ppm, Si: 5 to 80 p
pm and Cu: 5 to 150 ppm, and the balance is made of an aluminum alloy containing impurities.

According to a third aspect of the present invention, the aluminum clad material contains at least one layer of Al: 99.60 wt% or more, and contains Sc and Zr in an amount of Sc: 10 ppm or more.
0 ppm, Zr: 10 ppm or more and less than 2000 ppm, and -400 ppm <2Sc-Zr <950 pp
m in a ratio that satisfies m, and the remainder is made of an aluminum clad material in which a reinforcing layer composed of impurities is clad, and at least one surface of the reinforcing layer is clad with an outer layer via an insert layer. : 99.
80% by weight or more, Fe: 5 to 60 ppm,
The insert layer contains Si: 5 to 80 ppm and Cu: 5 to 150 ppm, and the balance is made of an aluminum alloy containing impurities. The insert layer contains 99.80 wt% or more of Al and one of Fe, Si, and Cu. It is characterized in that the above elements are contained at a lower concentration than in the outer layer, and the balance is made of an aluminum alloy composed of impurities.

The aluminum foil for an electrode of an electrolytic capacitor of the present invention is obtained by rolling the aluminum clad material having the above-mentioned reinforcing layer.

That is, the aluminum foil for an electrolytic capacitor electrode according to claims 4 to 6 contains not less than 99.60% by weight of Al and not less than 10 ppm of Sc and Zr.
Less than 000 ppm, Zr: 10 ppm or more and 2000 pp
m and -400 ppm <2Sc-Zr <950
It is characterized in that an etching layer made of aluminum is clad on at least one surface of a reinforcing layer containing impurities at a ratio satisfying ppm, and the remainder made of impurities.
The etching layer has an aluminum purity of 99.80 wt%.
High purity aluminum or Al: 99.80 wt
%: Fe: 5 to 60 ppm, Si:
5 to 80 ppm and Cu: 5 to 150 ppm,
The balance is preferably made of an aluminum alloy containing impurities.

The aluminum foil for an electrode of an electrolytic capacitor according to claim 7 contains Al: 99.60% by weight or more and contains Sc and Zr in an amount of Sc: 10 ppm or more.
0 ppm, Zr: 10 ppm or more and less than 2000 ppm, and -400 ppm <2Sc-Zr <950 pp
m in an aluminum foil in which an etching layer is clad on at least one surface of a reinforcing layer containing impurities with an insert layer interposed therebetween, wherein the etching layer contains Al: 99.80 wt% or more. In addition to the above, the insert layer contains 5 to 60 ppm of Fe, 5 to 80 ppm of Si, and 5 to 150 ppm of Cu, and the balance is made of an aluminum alloy including Al impurities. The insert layer contains 99.80 wt% or more of Al. , Fe,
It is characterized in that one or more elements of Si and Cu are contained at a lower concentration than in the etching layer, and the remainder is made of an aluminum alloy containing impurities.

Further, in each of the above aluminum foils for electrolytic capacitor electrodes, the etching layer has a Pb of 5 to 1000 pp at a surface layer portion having a depth of 0.1 μm from the surface.
m or Sn: contains at least one of 25 to 5000 ppm, or in the etching layer, 80% or more of crystal grains having a deviation angle of 10 ° or less from the cubic orientation {001} <100> on the foil surface. Is preferred.

In the aluminum clad material and the aluminum foil for an electrolytic capacitor electrode of the present invention, the reinforcing layer is formed by adding a trace amount of S to a high-purity aluminum matrix.
c and Zr are added at a predetermined ratio to obtain fine Al-Sc-
The strength and elongation are ensured by depositing a Zr-based intermetallic compound. The Al-Sc-Zr-based intermetallic compound is a simple substance of Sc or Zr, or Al ₃ Sc, Al ₃ Z
The effect of delaying the recrystallization is greater than that of r, and the strength can be synergistically improved as compared with an alloy to which Sc and Zr are individually added. Further, the crystal grains are fine and the elongation is good even after recrystallization.

Generally, high-purity aluminum foil for electrodes is
300 in the drying process and the chemical conversion process after etching.
Exposure to a high temperature atmosphere of ℃ or higher. At this time, even if the hard foil is used, softening or recrystallization occurs, and the strength is reduced. Further, in the case of a soft foil, the crystal grain size increases due to the high Al purity, and the number of crystal grains in the thickness direction decreases, resulting in a decrease in elongation and bending strength. In response to such a phenomenon, by adding trace amounts of Sc and Zr to Al at a predetermined ratio, recrystallization after final annealing is delayed, and recrystallization into fine grains is performed. Can be maintained. And S
By cladding the etching layer with the reinforcing layer to which c and Zr are added, an aluminum foil having excellent strength and elongation can be obtained without impairing the etching characteristics.

In the chemical composition of the reinforcing layer, the Al purity needs to be 99.60% by weight or more in order to control the amount of impurities and prevent the etching characteristics from being deteriorated due to excessive melting.

The significance of addition of Sc and Zr and the reasons for limiting the contents are as follows.

As described above, Sc delays recrystallization after final annealing, in other words, softening, and refines crystal grains even after recrystallization, thereby contributing to improvement in the strength and elongation of the alloy. In order to obtain the above effect, the Sc content needs to be 10 ppm or more.
It is difficult to maintain the characteristics of high-purity aluminum by securing 60 wt% or more, and it is disadvantageous in terms of cost.
The Sc content is preferably from 10 ppm to less than 500 ppm, particularly preferably from 50 ppm to less than 500 ppm.

Zr contributes to the improvement of the strength and elongation of the alloy by delaying recrystallization and making the crystal grains finer, like Sc. In order to obtain the above effects, the Zr content needs to be 10 ppm or more. On the other hand, if it is 2000 ppm or more, it is difficult to secure 99.60 wt% or more of the Al content and maintain the characteristics of high-purity aluminum. Zr content is 10p
pm or more and less than 500 ppm, particularly 50 ppm
It is preferably at least 500 ppm.

After defining the contents of Sc and Zr within the above ranges, these elements were further added with -400 ppm <2.
The ratio satisfies Sc-Zr <950 ppm. Sc
And Zr are added in the above-mentioned ratio, whereby Al-S
efficiently forming and depositing a c-Zr-based intermetallic compound,
These synergistic effects can be promoted. If the ratio is out of the above range, Sc and Zr alone or Al ₃ Sc or Al
_{3 The} amount present as Zr increases, and Al-Sc-Z
The synergistic effect of Sc and Zr due to the r-based precipitate cannot be sufficiently obtained.

The aluminum clad material of the first aspect has the reinforcing layer in at least one layer, and the composition of the other layers is not limited.

The aluminum clad material according to claim 2 has the reinforcing layer on at least one layer, and an outer layer is clad on at least one surface of the reinforcing layer, wherein the outer layer is Al: 99.80 wt% or more. And Fe:
5 to 60 ppm, Si: 5 to 80 ppm, and Cu: 5
１５０150 ppm, with the balance being an aluminum alloy consisting of Al impurities. The outer layer is a layer that becomes an etching layer when rolled and processed into foil, so that the Al purity needs to be 99.80 wt% or more in order to control the amount of impurities and prevent deterioration of etching characteristics due to overdissolution. is there.
Fe, Si and Cu are added for the purpose of suppressing abnormal grain growth (coarsening) of crystal grains during recrystallization. In addition, Cu has an effect of improving the etching property.
If the content of each element is less than the lower limit value, the above effect is poor, and if it exceeds the upper limit value, the etching property is impaired, resulting in overdissolution. A preferred lower limit of the Fe content is 8 ppm, and a preferred upper limit is 20 ppm. A preferred lower limit of the Si content is 8 ppm, and a preferred upper limit is 25 ppm. A preferred lower limit of the Cu content is 8 ppm, and a preferred upper limit is 80 ppm.

According to a third aspect of the present invention, there is provided an aluminum clad material having at least one reinforcing layer, and an outer layer having the above composition clad on at least one surface of the reinforcing layer via an insert layer. The insert layer is Al: 99.8
0 wt% or more, one or more elements of Fe, Si, and Cu are contained at a lower concentration than in the outer layer, and the balance is composed of an aluminum alloy composed of impurities, and the additive element is lower than the outer layer. Incorporation in a concentration ensures that the etch pits prevent growth in the thickness direction, which would erode the reinforcing layer that becomes the core during etching, secure the thickness of the core, and improve the bending strength. The strength is maintained by suppressing the decrease.

The aluminum foil for each electrode of the electrolytic capacitor of the present invention is a foil having a laminated structure in which an etching layer is clad on a core material composed of the reinforcing layer. These aluminum foils are produced by foil rolling an aluminum clad material, in which various aluminum layers serving as etching layers are clad on one or both surfaces of a reinforcing layer having the above composition, to a required thickness.
Since the strength of the foil is ensured by the presence of the reinforcing layer, it is possible to increase the surface area of the etching layer and to increase the capacitance.

Specifically, as shown in FIG. 1A, the aluminum foil for an electrolytic capacitor electrode according to claims 4 to 6 has an etching layer (12) on one or both sides of a reinforcing layer (11) serving as a core material. ) Is a foil of a two-layer or three-layer structure clad with (1). FIG. 1A shows a foil (1) having a three-layer structure in which the etching layers (12) and (12) are clad on both surfaces of the reinforcing layer (11).

[0029] The aluminum foil according to claim 5 has 99.8 excellent etching characteristics as the etching layer (12).
High-purity aluminum of 0% or more, preferably 99.90% or more is used.

The aluminum foil according to claim 6 contains, as the etching layer (12), not less than 99.80 wt% of Al, 5 to 60 ppm of Fe, and 5 to 80 ppm of Si.
ppm and Cu: 5 to 150 ppm, the balance being A
1 and an aluminum alloy comprising impurities, that is, the same composition as the outer layer in the aluminum clad material,
By adding these elements, the etching characteristics are improved and the area coverage is improved.

The aluminum foil for an electrode of an electrolytic capacitor according to claim 7 is an aluminum foil in which an etching layer is clad on at least one side of a reinforcing layer of the composition via an insert layer. .
80% by weight or more, Fe: 5 to 60 ppm,
An aluminum alloy containing 5-80 ppm of Si and 5-150 ppm of Cu with the balance being Al impurities, that is, the same composition and composition as the outer layer of the aluminum clad material, and the insert layer contains 99.80 wt% of Al.
In addition to the above, one or more elements of Fe, Si, and Cu are contained at a lower concentration than in the etching, and the remainder is constituted by an aluminum alloy composed of impurities, that is, an insert layer in the aluminum clad material. . That is, as shown in FIG. 1B, a three-layer or five-layer foil in which an etching layer (12) is clad on one or both sides of a reinforcing layer (11) via an insert layer (13). FIG. 1B shows a five-layer foil (2) in which the etching layers (12) and (12) are clad on both sides of the reinforcing layer (11) via the insert layer (13). . The additive element is the etching layer (1
Insert layer (13) contained at a lower concentration than 2)
Is to surely prevent the growth of the etch pit on the reinforcing layer (11) at the time of etching, secure the thickness of the core material, suppress the decrease in bending strength, and maintain the strength.

In any of the above-mentioned aluminum foils, a depth of 0.1 μm from the surface of the etching layer (12).
At least one of Pb and Sn is contained in the surface layer portion of m, and the effect of containing these elements to generate etch pits with high density and uniform distribution at the initial stage of etching to improve the surface area ratio. There is. The effect is that the Pb content is less than 5 ppm or the Sn content is less than 25 ppm.
If the content is less than 1 ppm, the effect is poor.
More than 000ppm or Sn content is 5000ppm
If it exceeds 300, surface melting occurs and a high capacitance foil cannot be obtained. Further, if such a Pb-Sn concentrated layer is formed in a surface layer portion having a depth of 0.1 μm from the surface, the above-described effect can be obtained. The preferred lower limit of the Pb content is 1
0 ppm, and a preferable upper limit is 500 ppm. Sn
A preferred lower limit of the content is 50 ppm, and a preferred upper limit is 2500 ppm. In addition, the etching layer (12)
The method for forming the Pb-Sn concentrated layer on the surface layer portion of the above is not particularly limited, and examples thereof include a method of vapor-depositing these elements or alloys, and further performing a heat diffusion treatment.

In any of the above aluminum foils, in order to secure the strength of the foil, it is preferable that the etching layer (12) has a crystal structure having a high cubic orientation occupancy on the foil surface. This is because if the difference in cubic orientation of the etched surface is large, the amount of dissolution of the foil surface at the time of etching increases, the foil thickness becomes partially thin, and local strength is reduced. Further, by maintaining the foil strength, the area expansion ratio can be increased, and the capacitance can be increased. Since such an overdissolution phenomenon occurs in units of crystal grains, it is desirable that the number of crystal grains having a large deviation from the cubic orientation be as small as possible. Specifically, on the foil surface,
Angle of deviation from cubic orientation {001} <100> is 10 °
It is necessary that the following crystal grains occupy 80% or more,
In particular, a remarkable effect is obtained when occupying 95% or more. Such a crystal structure is obtained by, for example, heat treatment after foil rolling, and specifically, heat treatment at 200 to 280 ° C. for 1 to 48 hours can be exemplified.

The aluminum foil for an electrolytic capacitor electrode of the present invention does not limit the thickness of the foil or the ratio of the thickness of the reinforcing layer (core material) to the thickness of the etching layer. When the ratio of the core material is set to be high, the bending resistance is improved, but on the other hand, the etching layer is relatively thin, so that the enlargement ratio is not increased and a high capacitance cannot be obtained. Conversely, when the etching layer ratio is set high, the area expansion ratio is improved, but the bending strength is reduced. As a range in which the improvement in the bending strength is recognized and a high capacitance can be secured, the core material ratio is 10 to 60 in the case of single-sided cladding.
%, And 5 to 40% in the case of double-sided cladding can be recommended. Also, when the insert layer is clad, the core material ratio is preferably maintained in the above range.

The aluminum foil for an electrode of an electrolytic capacitor according to any one of claims 4 to 7 can be suitably used as any one of a high-pressure foil, a low-pressure foil and a cathode foil. Can be used.

[0036]

Next, specific examples of the aluminum clad material and the aluminum foil for an electrode of an electrolytic capacitor of the present invention will be described in detail.

(Example 1) First, the alloy No. 1 to be a reinforcing layer (core material) shown in Table 1 was used. Aluminum ingots of five compositions b to f were sequentially subjected to face milling, hot rolling and cold rolling to produce flat plates each having a thickness of 5 mm. On the other hand, the alloy No. to be the outer layer (etching layer) With respect to the aluminum ingot a, 2.5 mm, 5 mm, 10 mm and 22.5 mm flat plates were similarly prepared. Then, the etching layers (a material) were formed on both surfaces of the core material (b to f materials) in the combinations and the core material ratios shown in Table 2.
And hot rolling, cold rolling, and foil rolling were performed to produce aluminum foil having a three-layer structure with a thickness of 0.13 mm. Further, these aluminum foils were subjected to a heat treatment at 250 ° C. × 2 hours, then cold-rolled to a thickness of 0.1 mm, and further subjected to a final annealing at 500 ° C. × 4 hours in vacuum to obtain test materials. .

Next, each of the manufactured test materials was etched under the following conditions without any pretreatment.

Primary etching: liquid composition 5% HCl + 10
% H ₂ SO 4, liquid temperature 75 ° C., current density C. 20A /
dm ² , time 100 sec Secondary etching: liquid composition 5% HCl, liquid temperature 85 ° C., current density C. The bending strength of the etched foil was measured at 5 A / dm ² for 8 min, and the bending strength of Comparative Example 1 consisting of only the etched layer was relatively evaluated as 100%. Further, after the chemical conversion treatment, the capacitance was measured, and Comparative Example 1 was relatively evaluated as 100%. Table 2 shows the results.

[0040]

[Table 1]

[0041]

[Table 2]

Example 2 First, as shown in Table 3, an alloy No. to be an outer layer (etching layer) was used. g and alloy No. used as the reinforcing layer (core material). For aluminum ingot of composition k, face milling,
Hot rolling and cold rolling were sequentially performed to produce flat plates each having a thickness of 5 mm. On the other hand, alloy No. h ~
A 1 mm flat plate was similarly prepared for the aluminum ingot j. Then, in the combinations shown in Table 4, the core material (k
The insert layers (h to j materials) were overlapped on both sides of the material, and the two sides were sandwiched by an etching layer (g material) to form a five-layer structure, and the width ends were welded at several places and fixed in a laminated state. This laminate is hot rolled and cold rolled to a thickness of 0.1
A 3 mm aluminum foil was produced. Furthermore, after subjecting these aluminum foils to heat treatment at 250 ° C. for 2 hours,
Cold-rolled to a thickness of 0.1mm, and then 500 ℃ in vacuum
A final annealing was performed for 4 hours to obtain a test material.

Next, each of the manufactured test materials was etched under the following conditions without any pretreatment.

Primary etching: liquid composition 5% HCl + 10
% H ₂ SO 4, liquid temperature 75 ° C., current density C. 20A /
dm ² , time 100 sec Secondary etching: liquid composition 5% HCl, liquid temperature 85 ° C., current density C. Folding strength of the etched foil was measured at 5 A / dm ² for 8 min, and the bending strength of Comparative Example 11 consisting of only the etched layer was relatively evaluated as 100%. Further, after the chemical conversion treatment, the capacitance was measured, and comparative example 11 was relatively evaluated as 100%. Table 4 shows the results.

[0045]

[Table 3]

[0046]

[Table 4]

Example 3 First, as shown in Table 5, the alloy No. as an outer layer (etching layer) was used. m and alloy No. used as the reinforcing layer (core material). The aluminum ingot o was subjected to face milling, hot rolling, and cold rolling in order to produce flat plates each having a thickness of 5 mm. On the other hand, alloy No. A 1 mm flat plate was similarly prepared for the n ingot.
Then, as in Experimental Example 2, an insert layer (n material) is superimposed on both surfaces of the core material (o material), and furthermore, both sides thereof are sandwiched by an etching layer (m material) to form a five-layer structure, and several width end portions are welded. And fixed in a laminated state. The laminate was subjected to hot rolling and cold rolling to produce aluminum foils each having a thickness of 0.13 mm. Furthermore, heat treatment conditions A: 150 ° C. × 2 hours, heat treatment conditions B: 250 ° C.
× 2 hours or heat treatment condition C: Intermediate annealing was performed under any of conditions of 350 ° C. × 2 hours, and cold-rolled to a further thickness of 0.1 mm. Further, with respect to Inventive Examples 33 and 34, after Pb or Sn was vapor-deposited on the foil surface, all the foils were subjected to final annealing at 500 ° C. for 4 hours in a vacuum to obtain test materials.

Next, each of the manufactured test materials was etched under the following conditions without any pretreatment.

Primary etching: liquid composition 5% HCl + 10
% H ₂ SO 4, liquid temperature 75 ° C., current density C. 20A /
dm ² , time 100 sec Secondary etching: liquid composition 5% HCl, liquid temperature 85 ° C., current density C. The bending strength of the etched foil was measured at 5 A / dm ² for 8 min, and the bending strength of Comparative Example 31 consisting of only the etching layer was relatively evaluated as 100%. Further, after the chemical conversion treatment, the capacitance was measured, and comparative example 31 was relatively evaluated as 100%. Table 6 shows the results.

On the other hand, the (100) occupancy of the test material was examined. The investigation method is to remove the oxide film formed on the surface of the test material at high temperature with an electropolishing liquid of perchloric acid: ethanol = 1: 4, then measure the crystal orientation of each crystal grain using an EBSP device, and determine the cubic orientation. The number of crystal grains whose plane orientation deviation angle from {001} <100> was 10 ° or less was counted, and was calculated as a percentage of the total number of measured grains. In addition, Invention Examples 33 and 34
For the foil of No. 1, the surface layer was dissolved to a depth of 0.1 μm with a sodium hydroxide solution, and the Pb content and the Sn content of the solution were analyzed. The results are shown in Table 6.

[0051]

[Table 5]

[0052]

[Table 6]

From the results of Tables 2, 4 and 6, it was confirmed that the aluminum foil of the present invention has both excellent capacitance and bending strength.

[0054]

As described above, each aluminum clad material of the present invention has at least one layer of Al: 9.
Containing not less than 9.60 wt%, and Sc and Zr,
Sc: 10 ppm or more and less than 1000 ppm, Zr: 10
not less than 2000 ppm and less than 2000 ppm, and -400 ppm
<2Sc-Zr <950 ppm in a ratio satisfying,
The strength of the cladding material is excellent because the reinforcing layer whose remainder is made of impurities is clad.

An outer layer is clad on at least one surface of the reinforcing layer having the above composition, and the outer layer is formed of Al: 99.
80 wt%, Fe: 5 to 60 ppm, Si: 5 to 8
An aluminum clad material containing an aluminum alloy containing 0 ppm and Cu: 5 to 150 ppm and the balance being an impurity, or an outer layer of the above composition clad on at least one surface of a reinforcing layer of the above composition via an insert layer; An aluminum cladding comprising a layer containing 99.80 wt% or more of Al, one or more elements of Fe and SiCu at a lower concentration than in the outer layer, and the balance being an aluminum alloy comprising impurities The material has excellent strength, and when rolled and used as an aluminum foil for an electrolytic capacitor electrode, it is possible to increase the surface area by etching, and an increase in capacitance can be expected.

In the aluminum foil for an electrolytic capacitor electrode of the present invention, the reinforcing layer is clad with an etching layer on at least one surface thereof, so that the foil strength is improved.
And by improving the foil strength, it is possible to increase the area expansion ratio,
High capacitance can be achieved. Therefore, the etching characteristics are secured by the etching layer, and the bending strength and elongation of the foil are secured by the reinforced layer to which trace amounts of Sc and Zr are added, so that it is possible to further improve the surface area. It has both capacitance and strength. Particularly, the etching layer has an aluminum purity of 99.80 wt%.
High purity aluminum or Al: 99.80 wt
%: Fe: 5 to 60 ppm, Si:
5 to 80 ppm and Cu: 5 to 150 ppm,
When the remainder is made of an aluminum alloy containing impurities, the etching characteristics are more excellent and the capacitance can be increased.

The aluminum foil for an electrolytic capacitor electrode has an etching layer of the above composition clad on at least one side of the reinforcing layer of the above composition via an insert layer, and the insert layer has an Al content of 99.80 wt% or more. And containing one or more elements of Fe, Si, and Cu at a lower concentration than in the etching layer,
When the remainder is made of an aluminum alloy consisting of impurities, the insert layer reliably prevents growth in the direction of the foil thickness that erodes the reinforcing layer of the etch pits, secures the thickness of the core material and The strength can be maintained by suppressing a decrease in the folding strength.

Further, in each of the above aluminum foils for an electrolytic capacitor electrode, the etching layer may have a Pb of 5 to 1000 pp at a surface layer portion having a depth of 0.1 μm from the surface.
When at least one of m or Sn: 25 to 5000 ppm is contained, etch pits are generated in a high density and uniform distribution at the initial stage of etching, so that the surface area can be further increased and the capacitance is increased. Becomes possible.

Further, when the etching layer occupies 80% or more of crystal grains having a deviation angle of 10 ° or less from the cubic orientation {001} <100> on the foil surface, overdissolution due to etching is prevented. A decrease in foil strength is suppressed, and the area enlargement ratio can be further increased, so that a higher capacitance can be achieved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an aluminum foil for an electrolytic capacitor electrode according to the present invention, in which (A) is a three-layer structure foil in which an etching layer is clad on both sides of a reinforcing layer, and (B) is a foil on both sides of the reinforcing layer. This is a five-layer structure foil in which an etching layer is clad via an insert layer.

[Explanation of symbols]

 1,2 ... aluminum foil for electrolytic capacitor electrode 11 ... reinforced layer (core material) 12 ... etched layer 13 ... insert layer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Zhang Susumu, Showa Aluminum Co., Ltd., 6, 224 Kaiyamacho, Sakai City (72) Inventor Kenki Kobayashi, 6224, Kaiyamacho, Sakai City, Showa Aluminum Co., Ltd. F term (reference) 4E067 AA05 AB03 AD02 BB01 BB02 BD01 BD03 DD01 EA00 EB11

Claims (9)

[Claims] (1) at least one layer of Al: 99.60 wt.
% Or more, and Sc and Zr are represented by Sc: 10
ppm to less than 1000 ppm, Zr: 10 ppm to less than 2000 ppm, and -400 ppm <2Sc-
An aluminum clad material containing Zr <950 ppm in a ratio satisfying the condition and a cladding of a reinforcing layer whose balance is made of impurities. 2. At least one layer of Al: 99.60 wt.
% Or more, and Sc and Zr are represented by Sc: 10
ppm to less than 1000 ppm, Zr: 10 ppm to less than 2000 ppm, and -400 ppm <2Sc-
An aluminum clad material containing Zr <950 ppm in a ratio satisfying the condition, and a reinforcement layer composed of impurities as a balance, and an outer layer clad on at least one surface of the reinforcement layer, wherein the outer layer is Al: 99. An aluminum clad material containing 80 wt% or more, Fe: 5 to 60 ppm, Si: 5 to 80 ppm, and Cu: 5 to 150 ppm, the balance being made of an aluminum alloy containing impurities. 3. Al: 99.60 wt.
% Or more, and Sc and Zr are represented by Sc: 10
ppm to less than 1000 ppm, Zr: 10 ppm to less than 2000 ppm, and -400 ppm <2Sc-
An aluminum clad material containing Zr <950 ppm in a ratio satisfying the balance, the remainder being clad with a reinforcing layer made of impurities, and further having an outer layer clad on at least one surface of the reinforcing layer via an insert layer, wherein the outer layer is , Al: 99.80 wt% or more, Fe: 5 to 60 ppm, Si: 5 to 80 ppm, and Cu: 5 to 150 ppm, the balance being composed of an aluminum alloy containing impurities. An aluminum clad containing 99.80 wt% or more, containing one or more elements of Fe and SiCu at a lower concentration than in the outer layer, and the balance being an aluminum alloy comprising impurities Wood. 4. An alloy containing not less than 99.60% by weight of Al and not less than 1000 ppm of Sc and not less than 1000 ppm of Sc and Zr.
ppm, Zr: 10 ppm or more and less than 2000 ppm, and -400 ppm <2Sc-Zr <950 ppm
An aluminum foil for an electrode for an electrolytic capacitor, characterized in that an etching layer made of aluminum is clad on at least one surface of a reinforcing layer made of impurities, with the balance being satisfied. 5. The aluminum foil for an electrolytic capacitor electrode according to claim 4, wherein said etching layer is made of high-purity aluminum having an aluminum purity of 99.80 wt% or more. 6. The etching layer has an Al content of 99.80.
wt% or more, Fe: 5 to 60 ppm, S
5. The aluminum foil for an electrolytic capacitor electrode according to claim 4, wherein the aluminum foil contains i: 5 to 80 ppm and Cu: 5 to 150 ppm, with the balance being an aluminum alloy containing impurities. 7. An alloy containing not less than 99.60% by weight of Al and not less than 10 ppm of Sc and not more than 1000 ppm of Sc and Zr.
ppm, Zr: 10 ppm or more and less than 2000 ppm, and -400 ppm <2Sc-Zr <950 ppm
Is an aluminum foil in which an etching layer is clad on at least one surface of a reinforcing layer composed of impurities with an insert layer interposed therebetween, wherein the etching layer contains Al: 99.80 wt% or more. In addition, Fe: 5 to 60 ppm, Si: 5 to 80 pp
The insert layer contains 99.80 wt% or more of Al and one or more elements of Fe, Si, and Cu. Is contained at a lower concentration than in the etching layer, and the remainder is made of an aluminum alloy containing impurities. 8. The etching layer has a depth of 0.1 mm from the surface.
The aluminum foil for an electrolytic capacitor electrode according to any one of claims 4 to 7, wherein the surface layer portion of 1 µm contains at least one of Pb: 5 to 1000 ppm or Sn: 25 to 5000 ppm. 9. The etching layer according to claim 1, wherein the etching layer comprises:
Angle of deviation from cubic orientation {001} <100> is 10 °
The aluminum foil for an electrolytic capacitor electrode according to any one of claims 4 to 8, wherein the following crystal grains occupy 80% or more.