JPS63153811A - Aluminum alloy foil for electrolytic capacitor cathode - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to an aluminum alloy foil for electrolytic capacitor cathodes.

In this specification, "26" indicates "rim%".

Prior art and its problems In order to improve the performance of electrolytic capacitors, it is necessary to increase not only the capacitance of the anode foil but also the capacitance of the cathode foil. In order to increase the capacitance of foil, it is effective to increase the surface area by etching the foil and forming fine recesses uniformly to high density on the surface of the foil. If it becomes excessive, the corrosion loss will also be excessive, resulting in a decrease in the capacitance of the foil and also in its mechanical strength.

Furthermore, in order to reduce the size and weight of capacitors, it is necessary to reduce the thickness of the foil, and to achieve this, the strength of the foil must be increased. Therefore, the conditions that an aluminum alloy foil for an electrolytic capacitor cathode must meet are that it has a large capacitance, that the amount of corrosion loss during machining and sowing is not excessive and is appropriate, and that it has high mechanical strength. .

Although various aluminum alloy foils for electrolytic capacitor cathodes have conventionally existed, the reality is that there has been no foil that satisfies all of the above three conditions.

An object of the present invention is to provide an aluminum alloy foil for an electrolytic capacitor cathode that can satisfy all of the above conditions.

Means for Solving the Problems The aluminum alloy foil for an electrolytic capacitor cathode according to the present invention contains 0.03 to 1.0% silicon and 0.2 to 2% manganese.
．． 0%, and further contains at least one of 0.1 to 1.0% copper and 0.003 to 063% vanadium, with the remainder consisting of aluminum and inevitable impurities. .

Silicon and manganese have the property of increasing the capacitance of aluminum alloy foil by including them both in aluminum, but when the silicon content is less than 0.03% and the manganese content is 0.2%, If the silicon content exceeds 1.0% and the manganese content exceeds 2.0%, a fine etched structure cannot be obtained and the capacitance of the foil will be small. Become,
Corrosion loss also becomes excessive. Therefore, the silicon content should be 0.03 to 1.0%, and the manganese content should be 0.2 to 2.0%.
It should be selected within the range of 0%.

The reason why the capacitance of aluminum alloy foil increases by containing both silicon and manganese is as follows. In other words, as is well known, the capacitance of aluminum alloy foil is proportional to the surface area of the foil, and in order to increase the surface area of the foil, it is necessary to uniformly and densely form four fine parts on the surface of the foil by etching. be.

When aluminum contains 0.03% or more of silicon and 0.2% or more of manganese, a large number of fine AIAl-5i-compounds form in aluminum.
Tissues dispersed in a matrix can be obtained. A
Since the lAl-8L- compound is potentially noble and has a large electrode potential difference with the aluminum matrix,
During etching, the aluminum matrix is preferentially attacked, resulting in uniform and dense formation of fine depressions on the surface of the foil, increasing its surface area. however,
Silicon content exceeds 1.0%, manganese content exceeds 2.
．． If it exceeds 0%, the Al-5t-Mn compound becomes coarse and not uniformly dispersed in the alloy foil, making it impossible to obtain a fine etched structure and lowering the capacitance.

In addition, in the above, when at least one of copper and vanadium is contained in an aluminum alloy, the solid solubility limit of silicon and manganese is lowered, and more AIAl-8i-compounds are precipitated. It can be solid-dissolved in the zero-body aluminum matrix to improve the etching properties of the matrix and enhance the effects of containing silicon and manganese as described above.

However, if the copper content is less than 0.1% and the vanadium content is less than 0.003%, the above effects cannot be obtained; if the copper content exceeds 1.0% and the vanadium content is If it exceeds 0.3%, etching becomes excessive and the capacitance decreases. Therefore, the copper content is reduced to 0
゜Within the range of 1 to 1.0%, the vanadium content is 0.0
It should be selected within the range of 0.03 to 0.3%.

The aluminum alloy foil according to the present invention contains impurities such as iron that are unavoidable during manufacturing. Among these impurities, especially in the case of iron, if the content exceeds 0.5%, it will cause coarse particles during casting. Since the effect obtained by crystallizing the AI-SiAl-5i-compound and adding silicon and manganese as described above is inhibited, the content of iron among impurities is preferably 0.5% or less.

Example Examples of the present invention will be described below along with comparative examples.

After producing foils from 16 kinds of aluminum alloys having the compositions shown in the table below by a normal foil manufacturing method, these alloy foils were immersed in an aqueous solution of 3% hydrochloric acid and 0.5% oxalic acid at a liquid temperature of 60°C, 1 min 3 through an alternating current with a current density of 30 A/dd
Etching was performed for 0 seconds and the capacitance was measured. The results were as shown in the table below.

As is clear from the above table, in alloy LP, alloy A-K
The capacitance is larger than that of .

Effects of the Invention The aluminum alloy foil for electrolytic capacitor cathodes of this invention contains 0.03 to 1.0% silicon and 0.2 to 2.0% manganese.
%, it is possible to obtain a structure in which a large number of fine AtAt-5t compounds are dispersed in the aluminum matrix. Since the Al-8i-Mn compound is potentially noble and has a large electrode potential difference with the aluminum matrix, the aluminum matrix is preferentially corroded during etching, resulting in fine depressions on the surface of the foil. It is formed uniformly and densely, increasing its surface area and, as a result, significantly increasing its capacitance. Moreover, the corrosion loss does not become excessive. Furthermore, copper 0.1-1
．． Since it contains at least one of 0% and 0.003 to 063% of vanadium, it lowers the solid solubility limit of silicon and manganese and precipitates more AIAl-5i-compounds, and also forms an aluminum matrix. The effect of containing silicon and manganese as described above can be enhanced by solidly dissolving the silicon and manganese in the matrix and improving the etching properties of the matrix. Therefore, the capacitance becomes even larger.

that's all

Claims (1)

[Claims] Silicon 0.03-1.0%, manganese 0.2-2.0%
An aluminum alloy foil for an electrolytic capacitor cathode, which further contains at least one of 0.1 to 1.0% copper and 0.003 to 0.3% vanadium, with the balance being aluminum and inevitable impurities.