JP3895232B2 - Aluminum alloy foil for electrolytic capacitor cathode and method for producing the same - Google Patents

Description

【００１８】
表１から明らかなように本発明材は比較材、従来材より静電容量、引張強さ共に優れることがわかる。比較例１は中間焼鈍までの冷延率が低い、比較例２は中間焼鈍温度が低いため、Ａｌ−Ｆｅ−Ｍｎ系化合物の分散析出が少なく、静電容量が低い。比較例３はＺｎが多すぎ、比較例４はＣｕが多すぎ、比較例５はＭｎが多すぎ、比較例６はＦｅ／Ｓｉが高すぎて静電容量が低い。比較例７は中間焼鈍までの冷延率が高すぎて最終冷延率が低いので引張強さが低い。従来例１はＦｅ／Ｓｉが低すぎて実施例より静電容量が低い。従来例２はＦｅが少ないので引張強さが低い。
【００１９】
【発明の効果】
以上、説明したように本発明の製造方法によれば高容量、高強度の電解コンデンサ陰極用アルミニウム箔が得られる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing an aluminum alloy foil having high capacitance and high mechanical strength when used as an electrolytic capacitor.
[0002]
[Prior art]
As conventional techniques, an Al alloy in which Cu is added to a low-purity Al foil as in Japanese Patent Publication No. 44-25016, and an alloy in which the amount of Fe is regulated as low as in Japanese Patent Laid-Open No. 51-97518 have been proposed. The capacitance and strength were not sufficient.
[0003]
[Problems to be solved by the invention]
Fe, together many Mn amount, the electrostatic capacitance of more conventional materials by to appropriately disperse the Al-Fe-Mn compounds, to provide a production method made strength that obtained.
[0004]
[Means for Solving the Problems]
In order to solve the above problems, among the methods for producing an aluminum alloy foil for an electrolytic capacitor cathode of the present invention, the invention according to claim 1 is Si: 0.15 to 0.25% ( mass% , hereinafter the same), Fe: 0.35 to 0.70%, Cu: 0.10 to 0.50%, Mn: 0.2 to 2.0%, the balance being Al and inevitable impurities, and Fe / Si: 1. After hot rolling an alloy of 5 to 3.0, cold rolling at a rolling rate of 80 to 95% is performed until intermediate annealing, intermediate annealing at 300 to 500 ° C. is performed, and final cold rolling is performed. To do.
[0005]
The invention of the method for producing an aluminum alloy foil for an electrolytic capacitor cathode according to claim 2 is the invention according to claim 1, wherein the alloy is further Mg: 0.001 to 2.0%, Zn: 0.001 to It contains 0.5% of 1 type or 2 types.
[0007]
The matter limited by this invention is demonstrated below.
Si: 0.15-0.25%
Si has an action of suppressing excessive precipitation of the Al—Fe—Mn compound, but less than 0.15% is not preferable because the action is not sufficiently exhibited. If it exceeds 0.25%, excessive dissolution due to a decrease in purity occurs, which is not preferable.
[0008]
Fe: 0.35-0.70%
Fe is an element having the greatest influence on strength improvement and purity reduction. If it is less than 0.35%, the contribution to strength improvement is insufficient, and there is no cost merit. If it exceeds 0.70%, excessive dissolution due to a decrease in purity occurs, which is not preferable.
[0009]
Cu: 0.10 to 0.50%
Cu is easily dissolved in the matrix, and is added to increase the corrosion potential of the matrix, promote chemical dissolution, and contribute to the surface expansion ratio. If it is less than 0.10%, the potential difference between an Al—Fe—Mn compound described later and the matrix becomes large, and local dissolution occurs, which is not preferable. If it exceeds 0.50%, chemical dissolution proceeds excessively and causes excessive dissolution.
[0010]
Mn: 0.2 to 2.0%
Mn forms an Al—Fe—Mn-based compound, creates a potential difference with the matrix, and acts as a starting point of pits, so is added. If it is less than 0.2%, there is little dispersion precipitation of the Al—Fe—Mn compound, and a satisfactory etching form cannot be obtained. If it exceeds 2.0%, the particle size of the precipitated and dispersed compound becomes too large, resulting in a coarse and non-uniform etching form.
[0011]
Fe / Si: 1.5 to 3.0
The reason why Fe / Si: 1.5 to 3.0 is preferable is that the Al—Fe—Mn compound is appropriately dispersed to form a uniform etching form. If it is less than 1.5, the ratio of Si to Fe is high, and since precipitation is suppressed, precipitation of the Al—Fe—Mn compound is insufficient, and an appropriate starting point cannot be obtained. If it exceeds 3.0, the effect of suppressing the precipitation becomes small, so that the precipitation of Al—Fe—Mn-based compounds is large, which causes local dissolution, which is not preferable. Preferably it is 2.0-2.5.
[0012]
Mg: 0.001 to 2.0%, Zn: 0.001 to 0.5%
Add to improve mechanical strength. In both cases, the effect is less than 0.001%. If Mg exceeds 2.0%, local dissolution is not preferable. If Zn exceeds 0.5%, local dissolution is caused like Mg, which is not preferable.
[0013]
Cold rolling rate until intermediate annealing 80-95%
This is a driving force that causes precipitation of the Al—Fe—Mn compound in the subsequent intermediate annealing, and if it is less than 80%, sufficient precipitation cannot be obtained. If it exceeds 95%, the cold rolling rate up to the final foil thickness becomes insufficient, and the strength cannot be ensured.
[0014]
Intermediate annealing 300 ~ 500 ℃
This is for precipitating an Al—Fe—Mn compound, and the effect is less than 300 ° C. When the temperature exceeds 500 ° C., the precipitated Fe is re-dissolved and a sufficient precipitation state cannot be secured. In addition, although a batch type or a continuous annealing furnace may be sufficient as a process, the direction performed in a continuous annealing furnace becomes high.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below.
In the present invention, melting, casting and hot rolling are performed by a conventional method, cold rolling at a rolling rate of 80 to 95% is performed until intermediate annealing, intermediate annealing at 300 to 500 ° C. is performed, and final cold rolling is performed. Is preferred.
The aluminum foil obtained after the above steps are subjected to a surface roughening treatment and a predetermined chemical conversion treatment.
In addition, about roughening process and chemical conversion treatment conditions, this invention is not specifically limited, For example, it can carry out by a conventional method.
[0016]
【Example】
An alloy having the composition shown in Table 1 was melt cast and finished to a thickness of 7 mm by hot rolling. Subsequently, cold rolling was performed to the plate thickness shown in Table 1. Then, intermediate annealing was performed at a temperature shown in Table 1 in a continuous annealing furnace. Then, it was cold-rolled to a final thickness of 0.04 mm. Next, after immersion for 60 seconds in a mixed acid of 0.5 M sulfuric acid and 1.0 M hydrochloric acid at a liquid temperature of 80 ° C., 3 V formation was carried out in an ammonium adipate solution at 85 ° C., and the capacitance was measured. The capacitance was determined by relative comparison with the conventional example 1 as 100. Further, the tensile strength after the final cold rolling was measured as an index of strength, and was expressed by relative comparison with the conventional example 1 being 100.
[0017]
[Table 1]

[0018]
As is apparent from Table 1, the material of the present invention is superior in both capacitance and tensile strength to the comparative material and the conventional material. Since Comparative Example 1 has a low cold rolling rate until intermediate annealing, and Comparative Example 2 has a low intermediate annealing temperature, the Al—Fe—Mn compound is less dispersed and precipitated, and the capacitance is low. Comparative Example 3 has too much Zn, Comparative Example 4 has too much Cu, Comparative Example 5 has too much Mn, and Comparative Example 6 has too high Fe / Si and low capacitance. In Comparative Example 7, the tensile strength is low because the cold rolling rate until intermediate annealing is too high and the final cold rolling rate is low. Conventional Example 1 has a lower capacitance than Fe and Si because Fe / Si is too low. Conventional Example 2 has low tensile strength because Fe is low.
[0019]
【The invention's effect】
As described above, according to the manufacturing method of the present invention described high capacity, aluminum foil for electrolytic capacitor cathode of high strength is obtained.

Claims (2)

Si: 0.15-0.25% ( mass% , the same shall apply hereinafter), Fe: 0.35-0.70%, Cu: 0.10-0.50%, Mn: 0.2-2.0% After the hot rolling of the alloy consisting of the balance Al and inevitable impurities and Fe / Si: 1.5 to 3.0, cold rolling at a rolling rate of 80 to 95% is performed until intermediate annealing, The manufacturing method of the aluminum alloy foil for electrolytic capacitor cathodes which performs 300-500 degreeC intermediate annealing and performs final cold rolling. 2. The electrolytic capacitor cathode according to claim 1 , wherein the alloy further contains one or two of Mg: 0.001 to 2.0% and Zn: 0.001 to 0.5%. Manufacturing method of aluminum alloy foil.