JP3265382B2 - Aluminum alloy foil for electrolytic capacitor anode - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an aluminum alloy suitable as an aluminum foil for an electrode of an electrolytic capacitor, and more particularly to an aluminum alloy foil for an anode of an electrolytic capacitor.

[0002] In this specification, "%" means
It means “% by weight”.

[0003]

2. Description of the Related Art Generally, as an aluminum anode foil of an electrolytic capacitor, a small amount of C is used as necessary while minimizing the content of Fe and Si as impurity elements.
An aluminum alloy foil having a purity of 99.9% or more to which u is added is used.

As is well known, the surface area of these foils is increased by etching to increase the capacitance as a capacitor. However, Cu
It has been widely accepted that the conventional aluminum foil, which uses a small amount of alloying elements to suppress the content of Fe, Si, etc., has almost reached the limit of the increase in surface area achieved by improving the manufacturing process and the etching process. This is what the traders admit.

Since the increase in the surface area by etching corresponds to the decrease in the amounts of Fe and Si when focusing on the components contained in the aluminum foil, it is necessary to minimize the contents of these components. However, on the other hand, if these amounts are several ppm or less, the starting point of the etching pit is reduced, which leads to a decrease in the capacitance. Therefore, by adding a small amount of Cu as necessary, In addition, the solubility at the time of etching is imparted to further increase the surface area. However, the presence of Cu as a contained element may cause ineffective dissolution on the foil surface, so that the capacitance per unit dissolved amount after etching is not necessarily large. Further, there is also a disadvantage that the strength of the foil after etching is reduced due to unevenness of the foil surface caused by ineffective melting. Furthermore, the reactivity with the electrolytic solution after being assembled as a capacitor also increases with an increase in the amount of Cu, which may cause a reduction in product life.

[0006]

Accordingly, the present invention achieves the same effect when Cu as an additive element is exhibited in an aluminum alloy foil for an anode of an electrolytic capacitor.
First, a new alloy foil that can remove or reduce the adverse effects of Cu
The main purpose is to provide.

[0007]

Means for Solving the Problems The present inventor has conducted intensive studies in view of the state of the art as described above, and as a result, when a part or all of Cu is replaced by a specific additive element,
It has been found that the problems of the prior art are greatly reduced or substantially eliminated.

That is, the present invention provides the following aluminum alloy foil for an anode of an electrolytic capacitor: 1 The purity of aluminum is 99.9% or more;
An aluminum alloy foil for an anode of an electrolytic capacitor containing i in an amount of 0.001% or more and less than 0.005%.

(2) The purity of aluminum is 99.9% or more, and the content of Ti is 0.0005% or more and 0.005% or more.
An aluminum alloy foil for an anode of an electrolytic capacitor containing less than 0.0001 to 0.005% of at least one of Zn and Mn.

3 For an anode of an electrolytic capacitor having an aluminum purity of 99.9% or more, containing 0.001% or more and less than 0.005% of Ti, and containing 0.0001 to 0.005% of Cu. Aluminum alloy foil.

(4) The purity of aluminum is 99.9% or more, and the content of Ti is 0.0005% or more and 0.005% or more.
And at least one of Zn and Mn is contained in 0.0
001-0.005% and 0.0001 of Cu
Aluminum alloy foil for electrolytic capacitor anode containing 0.005% to 0.005%.

Hereinafter, the inventions described in the above items 1 to 4 will be described in detail as first to fourth inventions of the present application, respectively. In addition, in relation to matters common to all inventions, they may be simply referred to as the present invention.

The first invention of the present application The aluminum purity in the aluminum alloy foil used in the present invention is 99.9% or more.

In the first invention of the present application, the content of Ti is set to 0.001% or more and less than 0.005%. Ti is
Like Cu, it contributes to an increase in the surface area at the time of foil etching and has a function of suppressing ineffective dissolution of the foil surface at the time of etching, which is observed in a Cu-containing material. When the content of Ti is too small, the desired effect is not sufficiently exhibited. On the other hand, when the content of Ti is too large, the effect of increasing the surface area is reduced, and the leakage current after formation is also reduced. growing.

The aluminum purity in the aluminum alloy foil used in the second invention of the present application is:
As in the case of the first invention of the present application, the content is 99.9% or more.

In the second invention of the present application, the content of Ti is set to 0.0005% or more and less than 0.005%, and at least one of Zn and Mn is set to 0.0001% or less.
0.005% is contained. Such Ti and Zn and M
By coexisting with at least one kind of n, the above-mentioned effects (suppression of ineffective dissolution, enlargement of the surface area at the time of etching, etc.) due to the inclusion of Ti are further improved.

The aluminum purity in the aluminum alloy foil used in the third invention of the present application is:
As in the case of the first invention of the present application, the content is also 99.9% or more.

In the third invention of the present application, the content of Ti is set to 0.001% or more and less than 0.005%,
The Cu content is adjusted within the range of 0.0001 to 0.005%.

Cu is, as described above, Ti, Zn and M
It is believed that replacing essentially by Ti or by Ti and Zn and / or Mn is preferred, as it essentially increases the ineffective dissolution of the aluminum foil surface compared to n. However, the amount
When it is in the range of 0.0001 to 0.005%,
It has been found that it increases the solubility of aluminum during etching, does not cause ineffective melting, and is effective in forming uniform pits. If the contents of Fe and Si are reduced to about 0.001% or less, Ti, Z
Depending on the contents of n and Mn, aluminum may be softened at room temperature after rolling. In such a case, by adding up to 0.005% of Cu, the aluminum foil is softened during the manufacturing process. It is also necessary to avoid. By comprehensively judging these matters,
In the third invention of the present application, the content of Cu is set to 0.0001.
To within the range of 0.005%.

The aluminum purity in the aluminum alloy foil used in the fourth invention of the present application is as follows:
As in the case of the first invention of the present application, the content is also 99.9% or more.

In the fourth invention of the present application, the content of Ti in the aluminum alloy foil is set to not less than 0.0005% and not more than 0.005%.
The content of at least one of Zn and Mn is 0.0001 to 0.005%, and the content of Cu is 0.0001 to 0.005%. The reasons for defining the quantitative ranges of the respective components are as described in relation to the first to third inventions of the present application.

The aluminum alloy foil for an anode of an electrolytic capacitor according to the present invention may contain an allowable amount of unavoidable impurities as long as the properties of the anode foil are not impaired. Such inevitable impurities include iron (300 ppm
To about), silicon (up to about 300 ppm) and the like. The total amount of such unavoidable impurities is 400p
Preferably it does not exceed pm.

The aluminum alloy foil for an anode of an electrolytic capacitor according to the present invention is manufactured through steps such as melting, casting, rolling, and heat treatment according to a conventional method.

The processing as a material for an electrolytic capacitor such as an etching processing may be performed in the same manner as in a conventional method.

[0025]

According to the present invention, in an aluminum alloy foil for an anode of an electrolytic capacitor, ineffective dissolution of the foil surface can be suppressed, and the capacitance per unit dissolution after etching can be increased.

[0026]

EXAMPLES Examples and comparative examples are shown below to further clarify the features of the present invention.

Example 1 17 kinds of aluminum alloy slabs having the chemical compositions shown in Table 1 were cast by adding a predetermined amount of alloy components to a three-layer electrolytic base metal.

[0028]

[Table 1]

Each of the obtained slabs was subjected to hot and cold rolling by a conventional method, heat-treated to produce a foil having a thickness of 105 μm, and then annealed at 520 ° C. in vacuum for 5 hours.

The 17 kinds of foils thus obtained were subjected to electrolytic etching under the conditions shown in Table 2, and after measuring the dissolution loss, a chemical conversion treatment was performed and the capacitance was measured.

[0031]

[Table 2]

Table 3 shows the capacitance (Cap) and the dissolution loss (△).
W) and the capacitance per unit weight loss (Cap / △ W) calculated from these.

[0033]

[Table 3]

As is clear from the results shown in Table 3, the sample No. Sample Nos. 3, 4, and 6 to 13 are all comparative sample Nos. It is clear that the value of Cap / ΔW is larger than that of No. 1 and the ineffective dissolution is suppressed.

On the other hand, in Comparative Example Sample No. In Comparative Example Sample No. 2, the desired effect was not exhibited, while the Ti amount exceeded a predetermined value. In No. 5, the ineffective dissolution was rather large.

Further, Comparative Example Sample No. 14 and Sample No. 14 according to the present invention. As is clear from comparison with Nos. 15 to 17, the effect of addition of Ti or the like is exhibited even when the contents of Fe and Si are large.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Akiko Muroi 3-8-8 Kutaro-cho, Chuo-ku, Osaka City, Osaka Prefecture Inside Toyo Aluminum Co., Ltd. (72) Inventor Akihiko Takahashi 6 Kitahara, Tsukuba, Ibaraki Prefecture Sumitomo Chemical Co., Ltd. (72) Inventor Hideo Maeda 5-1 Sokaicho, Niihama-shi, Ehime Prefecture Sumitomo Chemical Industries, Ltd. (72) Inventor Hitoshi Yasuda 6 Kitahara, Tsukuba-shi, Ibaraki Pref. Takeshi Ogawa (56) References JP-A-4-62822 (JP, A) JP-A-1-104743 (JP, A) JP-A-54-98960 (JP, A) (58) Fields investigated (Int. . ^7, DB name) C22C 21/00 - 21/18

Claims (3)

(57) [Claims] An aluminum alloy having a purity of at least 99.9%, a Ti content of at least 0.0005% and less than 0.005%, and at least one of Zn and Mn at 0.0
001 to 0.005% , the balance being inevitable impurities.
Aluminum alloy foil for that electrolytic capacitor anode. 2. The composition according to claim 1, wherein the purity of the aluminum is 99.9% or more, the Ti content is 0.001% or more and less than 0.005%, and the Cu content is 0.0001 to 0.005% .
Aluminum alloy foil for electrolytic capacitor anode consisting of unavoidable impurities . 3. The purity of aluminum is not less than 99.9%, the content of Ti is not less than 0.0005% and less than 0.005%, and at least one of Zn and Mn is not less than 0.000%.
1 to 0.005% and 0.0001 to Cu
An aluminum alloy foil for electrolytic capacitor anodes containing 0.005% and the balance consisting of unavoidable impurities .