JP2006169629A - Aluminum alloy material for electrolytic capacitor, method for producing the same, method for producing electrode material for electrolytic capacitor, anode material for electrolytic capacitor and aluminum electrolytic capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive aluminum alloy material for an electrolytic capacitor having high electrolytic capacitance, a method for producing the same, a method for producing an electrode material for an electrolytic capacitor, an anode material for an electrolytic capacitor, and an aluminum electrolytic capacitor. <P>SOLUTION: The aluminum alloy material has a composition of, by mass, 0.006 to 0.05% Si, 0.006 to 0.05% Fe and 0.0005 to 0.03% Cu, wherein the content of Ga is ≤0.03%, each content of the other impurities is ≤0.02%, and the relationship of 0.0005≤(I<SB>Fe</SB>/C<SB>Fe</SB>+3I<SB>Si</SB>/C<SB>Si</SB>+5I<SB>Cu</SB>/C<SB>Cu</SB>)×C<SB>Fe</SB>≤0.015 is established between the respective contents, by mass%, of Fe, Si and Cu contained in intermetallic compounds extracted by a heat phenol dissolution method: I<SB>Fe</SB>, I<SB>Si</SB>and I<SB>Cu</SB>, and the respective contents, by mass%, of Fe, Si and Cu contained in the whole material: C<SB>Fe</SB>, C<SB>Si</SB>and C<SB>Cu</SB>. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrode material for an electrolytic capacitor having a high capacitance and a method for producing the same, a method for producing an electrode material for an electrolytic capacitor, an anode material for an electrolytic capacitor, and an aluminum electrolytic capacitor.

  In this specification, the term “aluminum” is used to include the alloy thereof, and the aluminum material includes a foil, a plate, and a molded body using these.

  For electrode materials for electrolytic capacitors, particularly those used for anodes, the surface area is generally increased by electrolytic etching. As the aluminum material used for this purpose, a high-purity aluminum alloy material having an aluminum purity of 99.98% by mass or more is used. This is because the amount of aluminum dissolved increases due to the presence of impurities exceeding the allowable amount, making it difficult to form fine etch pits. In addition, when this impurity forms an intermetallic compound in aluminum and the chemical solubility of the interface between the intermetallic compound alone or the aluminum matrix is high, the influence on the shape control of this etch pit becomes very large. .

For such problems, for example, a method of regulating the precipitation amount of Fe or Si (Patent Document 1), a method of regulating the precipitation amount of Fe, Si, and Cu (Patent Document 2), an Fe-containing intermetallic compound A technique (Patent Document 3) is disclosed in which the size and Fe content are regulated.
Japanese Patent Publication No. 3-61333 JP-A-8-209275 JP 2004-149835 A

  However, due to the recent cost reduction demand, when trying to use an inexpensive aluminum lump, the content of unavoidable impurities in aluminum, especially Fe, Si, Cu, is inevitably increased. There was a problem that it became difficult to obtain capacity.

  An object of the present invention is to provide an aluminum alloy material for electrolytic capacitors and a method for producing the same, a method for producing an electrode material for electrolytic capacitors, an anode material for electrolytic capacitors, and an aluminum electrolytic capacitor that are inexpensive and have a high capacitance.

  The above-mentioned subject is achieved by the following means.

(1) Si; 0.006 mass% to 0.05 mass%, Fe; 0.006 mass% to 0.05 mass%, Cu; 0.0005 mass% to 0.03% by mass Each of Fe, Si, and Cu contained in an intermetallic compound extracted by a hot phenol dissolution method, having Ga of 0.03% by mass or less and other impurities of 0.02% by mass or less. Rate: between each mass% of I _Fe , I _Si , I _{Cu and} each content ratio of Fe, Si, Cu contained in the whole material: 0.0005 ≦≦ each mass% of C _Fe , C _Si , C _Cu An aluminum alloy material for electrolytic capacitors, characterized by having a relationship of (I _Fe / C _Fe +3 I _Si / C _Si +5 I _Cu / C _Cu ) × C _Fe ≦ 0.015.

  (2) The recrystallization rate is 60% or more, the average crystal grain size of the recrystallized grains is 30 μm or more and 400 μm or less, and among the recrystallized grains, cubic orientation grains measured from the surface of the aluminum alloy material 2. The aluminum alloy material for electrolytic capacitors as described in 1 above, wherein the area occupancy is less than 20%.

(3) In each region of 25% or more of the thickness of the aluminum material from the surface of the aluminum material, the respective contents of Fe, Si, and Cu contained in the intermetallic compound extracted by the hot phenol dissolution method: I _Fe , 0.0005 ≦ (I _Fe / C) between each mass% of I _Si and I _{Cu and the} respective contents of Fe, Si and Cu contained in the whole material: C _Fe , C _Si and C _{Cu Fe} + 3I _Si / C _Si + 5I _Cu / C _Cu ) × C _Fe ≦ 0.015

  (4) Si; 0.006 mass% or more and 0.05 mass% or less, Fe; 0.006 mass% or more and 0.05 mass% or less, Cu; 0.0005 mass% or more and 0.03 mass% or less And after cold-rolling an aluminum plate material having a Ga content of 0.03% by mass or less and other impurities of 0.02% by mass or less at a reduction rate of 60% or more, the temperature is increased to 300 ° C. during the heat treatment. A method for producing an aluminum alloy material for electrolytic capacitors, characterized in that a temperature of 10 ° C./second or more is maintained, a range of 300 to 480 ° C. is retained for 1 second to 20 minutes, and then cooled.

  (5) The method for producing an aluminum alloy material for electrolytic capacitors as described in (4) above, wherein the residence time in the temperature range from 150 ° C. to 220 ° C. is from 1 hour to 24 hours, prior to the heat treatment. .

  (6) The aluminum alloy for electrolytic capacitors as described in 4 or 5 above, wherein the aluminum material having a thickness of 80 μm or more and 150 μm or less after cooling is subjected to additional rolling at a reduction ratio of 5% or more and 30% or less. A method of manufacturing the material

(7) Si; 0.006 mass% to 0.05 mass%, Fe; 0.006 mass% to 0.05 mass%, Cu; 0.0005 mass% to 0.03% by mass An aluminum plate having a Ga content of 0.03% by mass or less and other impurities of 0.02% by mass or less cast at a cooling rate of 1 × 10 ³ ° C./second or more, and then cooled. Then, the range of 360 to 480 ° C. is retained for 1 second to 10 hours, and then cooled, and then the method for producing an aluminum alloy material for electrolytic capacitors is provided.

(8) Si; 0.006 mass% to 0.05 mass%, Fe; 0.006 mass% to 0.05 mass%, Cu; 0.0005 mass% to 0.03% by mass An aluminum plate having a Ga content of 0.03% by mass or less and other impurities of 0.02% by mass or less cast at a cooling rate of 1 × 10 ³ ° C./second or more, and then cooled. Then, final annealing is performed at a temperature of 260 ° C. or higher and 330 ° C. or lower for a time of 1 hour or more and 10 hours or less, and a method for producing an aluminum alloy material for electrolytic capacitors,

  (9) The method for producing an aluminum alloy material for electrolytic capacitors as described in (8) above, wherein heat treatment is performed at a temperature of 220 ° C. or more and 250 ° C. or less for 1 hour or more and 5 hours or less prior to the final annealing.

  (10) The aluminum alloy material for electrolytic capacitors according to any one of items 7 to 9 above, wherein the aluminum plate material is produced by casting at least one surface of a melt of a material used for cold rolling in contact with a cooling roll. Production method.

  (11) A method for producing an electrode material for an electrolytic capacitor, comprising a step of etching the aluminum alloy material according to any one of items 1 to 3.

  (12) The method for producing an electrode material for electrolytic capacitors as described in 11 above, wherein at least a part of the etching is AC etching.

  (13) An anode material for an electrolytic capacitor produced by the production method according to the above item 11 or 12.

  (14) An aluminum electrolytic capacitor characterized in that an aluminum electrode material produced by the production method according to the above item 11 or 12 is used as the electrode material.

According to the invention described in the preceding item (1), 0.0005 ≦ (I _Fe / C _Fe +3 I _Si / C _Si +5 I _Cu / C _Cu ) × C while using an inexpensive aluminum material having a large amount of Fe. By having a relationship of _Fe ≦ 0.015, an aluminum material for electrolytic capacitors having a large surface expansion ratio by etching and a high capacitance can be obtained.

  According to the invention described in the above item (2), the recrystallization rate, the average crystal grain size of the recrystallized grains, and the area occupancy ratio of the cubic orientation grains are defined within a predetermined range. Can be realized.

According to the invention described in item (3) above, 0.0005 ≦ (I _Fe / C _Fe +3 I _Si / C _Si +5 I _Cu / C _{Cu in} the region of 25% or more of the thickness of the aluminum material from the surface of the aluminum material. ) × C _Fe ≦ 0.015, it can be an aluminum material for electrolytic capacitors that has a large area expansion ratio by etching and a high capacitance.

According to the invention described in the preceding item (4), 0.0005 ≦ (I _Fe / C _Fe +3 I _Si / C _Si +5 I _Cu / C _Cu ) × C _Fe ≦ 0.015 An aluminum material for electrolytic capacitors having a high rate and a high capacitance can be produced.

  According to the invention described in (5) above, since the residence time in the temperature range from 150 ° C. to 220 ° C. is set to 1 hour or more and 24 hours or less prior to the heat treatment, the electrolytic capacitor having a high capacitance is used. An aluminum material can be manufactured more reliably.

  According to the invention described in item (6) above, it is possible to provide a semi-rigid aluminum material for electrolytic capacitors having an excellent electrostatic capacity.

According to the invention described in the preceding item (7), 0.0005 ≦ (I _Fe / C _Fe +3 I _Si / C _Si +5 I _Cu / C _Cu ) × C _Fe ≦ 0.015 An inexpensive aluminum material for electrolytic capacitors having a high capacitance and a high capacitance can be produced.

According to the invention described in the preceding item (8), there is a relationship of 0.0005 ≦ (I _Fe / C _Fe +3 I _Si / C _Si +5 I _Cu / C _Cu ) × C _Fe ≦ 0.015, and surface expansion by etching An inexpensive aluminum material for electrolytic capacitors having a high capacitance and a high capacitance can be produced.

  According to the invention described in item (9) above, since the heat treatment is performed at a temperature of 220 ° C. or more and 250 ° C. or less for 1 hour or more and 5 hours or less prior to the final annealing, aluminum for electrolytic capacitors having a high capacitance is obtained. The material can be manufactured more reliably.

According to the invention described in the preceding item (10), the aluminum plate material is produced by casting at least one surface of the molten material of the material to be subjected to cold rolling in contact with the cooling roll, so that 1 × 10 ³ ° C./second or more Casting can be performed at a cooling rate of

  According to the invention described in the above item (11), it is possible to provide an inexpensive electrode material for an electrolytic capacitor having a large area expansion ratio and a high capacitance.

  According to the invention described in item (12) above, since at least a part of the etching is AC etching, an electrode material having a high capacitance can be provided by forming spongy etch pits.

  According to the invention described in the preceding item (13), an inexpensive anode material for an electrolytic capacitor excellent in capacitance can be obtained.

  According to the invention described in the preceding item (14), an aluminum electrolytic capacitor having a high surface area and an inexpensive electrode material and having a high capacitance can be obtained.

  Next, the configuration of the present invention and the reason thereof will be described.

  In the present invention, in order to enable application of an inexpensive aluminum material having a high Fe content in an electrolytic capacitor low-pressure material, among Fe, Si, and Cu contained in an intermetallic compound, in particular, Si and Cu. By controlling the total crystal precipitation amount while suppressing the content ratio, a material having good etching characteristics has been established. Regarding the improvement of Al-Fe-based intermetallic compounds and etching characteristics, the above-mentioned Japanese Patent Publication No. 3-61333 discloses the precipitation amount of Fe and Si, and JP-A-8-209275 discloses the precipitation of Fe, Si and Cu. Regarding the amount, Japanese Patent Application Laid-Open No. 2004-149835 discloses a technique regarding the shape, size, and amount of an intermetallic compound. These are effective methods for pit control during etching, but as the amounts of Fe and Si increase, the control of etch pits becomes increasingly difficult. Japanese Patent Laid-Open No. 63-312941 discloses a technique for suppressing leakage current after chemical conversion treatment by dissolving Fe and Si in aluminum. However, in order to obtain a fine etching pattern, it is more advantageous to use the precipitate as a nucleus than to a completely solid solution state.

  The present invention has led to the development of a technique that balances the problems of the area expansion ratio by etching and the leakage current during chemical conversion by controlling the composition ratio of Fe, Si, and Cu in the intermetallic compound. .

  First, if the Fe amount is less than 0.006% by mass, an increase in cost due to the raw metal used is unavoidable, and the effect of the present invention cannot be expected. Moreover, when it contains exceeding 0.05 mass%, a loss by dissolution will increase remarkably and will cause a capacitance fall and a capacitance variation. Next, if the amount of Si is less than 0.006% by mass, an increase in cost due to the aluminum ingot used is inevitable, and the effect of the present invention cannot be expected. Moreover, if it exceeds 0.05 mass%, it will be outside the control ratio range of Fe, Si, Cu of the present invention, so increase in dissolution weight loss due to coexistence with Fe cannot be suppressed, and the capacitance decreases And cause capacitance variation. If the amount of Cu is less than 0.0005% by mass, an increase in cost due to the aluminum ingot used is inevitable, and the effect of the present invention cannot be expected. Moreover, when it contains more than 0.03 mass%, it will become the control ratio range of Fe, Si, and Cu of this invention similarly to Si, so that the dissolution weight loss increases remarkably, and the capacitance decreases and the capacitance varies. Cause.

  Ga is defined as 0.03% by mass or less, and other impurities are each defined as 0.02% by mass or less. The purity of aluminum is desirably 99.8% by mass or more.

As a result of intensive studies on materials that do not impair the etching characteristics of the aluminum material having the above composition range, we have determined the respective contents of Fe, Si, and Cu contained in the intermetallic compound extracted by the hot phenol dissolution method: 0.0005 ≦ (I) between each mass% of I _Fe , I _Si , and I _{Cu and} each percentage content of Fe, Si, and Cu contained in the whole material: C _Fe , C _Si , and C _{Cu The} present invention was completed by controlling to have a relationship of _Fe / C _Fe + 3I _Si / C _Si + 5I _Cu / C _Cu ) × C _Fe ≦ 0.015.

If the ratio of ((I _Fe / C _Fe +3 I _Si / C _Si +5 I _Cu / C _Cu ) × C _Fe ) is less than 0.0005, the material is not sufficiently soluble and it is difficult to form fine etch pits. Become. Further, if it exceeds 0.015, the fine etching pits that greatly contribute to the surface expansion rate are likely to drop off. A more preferable ratio of ((I _Fe / C _Fe + 3I _Si / C _Si +5 I _Cu / C _Cu ) × C _Fe ) is
0.0005 ≦ (I _Fe / C _Fe +3 I _Si / C _Si +5 I _Cu / C _Cu ) × C _Fe ≦ 0.01,
The optimal range is
0.0008 ≦ (I _Fe / C _Fe +3 I _Si / C _Si +5 I _Cu / C _Cu ) × C _Fe ≦ 0.008.

  Next, regarding the recrystallization rate, if the recrystallization rate is less than 60%, the formation of ultrafine pits due to non-uniformity of etch pits due to partially non-recrystallized regions and the influence of processing strain is caused. Invalid pits are generated during processing, and the capacitance is reduced. Moreover, if the recrystallized grains are large, the yield strength and tensile strength at the time of tensile deformation are lowered, which causes cutting of the foil at the time of etching or chemical conversion treatment. For this purpose, the average grain size necessary for securing the proof stress and tensile strength required is 0.03 mm or more and 0.4 mm or less. In the case of the present invention, the area occupancy ratio of the cube-oriented grains measured from the surface is advantageous for further improvement of the capacitance by avoiding the mixture of non-cubic grains and cube-oriented grains. The area occupancy of the cubic oriented grains is preferably less than 20%. Further, the recrystallization rate is preferably 80% or more, the average crystal grain size of the recrystallized grains is 0.05 mm or more and 0.3 mm or less, and the optimum range is 0.05 mm or more and 0.2 mm or less. Further, the area occupancy of the cubic orientation grains is more preferably less than 15%, and the optimum range is less than 10%.

  The present invention is used for etching as a semi-hard material having a final annealing treatment or a processing strain of up to 5 to 30% after the treatment, but the recrystallization rate when annealed at that time is an etching property. affect. That is, when the non-recrystallization rate increases, the etching pattern becomes non-uniform, resulting in a decrease in capacitance.

  Next, the production method of the present invention is not particularly limited. For example, the purity of aluminum is 99.8% by mass or more, Si: 0.006% by mass to 0.05% by mass, Fe: 0.006 It has a composition of 0.05% by mass or more and 0.05% by mass or less, Cu; 0.0005% by mass or more and 0.03% by mass or less, Ga is 0.03% by mass or less, and other impurities are each 0.02% by mass or less. An aluminum alloy ingot produced by a semi-continuous casting method is subjected to a homogenization treatment before or after chamfering performed thereafter, and then cold rolling of 60% or more following hot rolling. Examples of the material subjected to the inter-rolling include heating at a temperature rising rate of 10 ° C./second or more, retaining the range of 300 to 480 ° C. for 1 second to 20 minutes, and then cooling.

By such heat treatment, a relationship of 0.0005 ≦ (I _Fe / C _Fe +3 I _Si / C _Si +5 I _Cu / C _Cu ) × C _Fe ≦ 0.015 can be realized.

  As an example of the above-mentioned heat treatment, a method of inserting a sheet into an already heated furnace or a continuous coil annealing treatment may be used. A more desirable condition for the heat treatment is to retain the range of 350 to 480 ° C. for 1 second or more and 10 minutes or less, and the optimum condition is for the range of 350 to 480 ° C. for 1 second or more and 5 minutes or less. It is to stay. According to such a method, a good etching pattern can be obtained even with a material having an Fe content of 0.006 mass% or more and 0.05 mass% or less.

  Further, the cooling after residence is not particularly limited, and examples thereof include furnace cooling, air cooling, fan cooling and the like according to a conventional method.

  Furthermore, when performing rapid annealing at a temperature of 300 ° C. or more and 480 ° C. or less, prior to this, by holding in a temperature range from 150 ° C. to 220 ° C., work strain is released in advance, and an intermetallic compound containing Fe It is possible to suppress the formation of coarse etching pits by controlling the precipitation. At this time, the object is also achieved by passing a time corresponding to the holding time through this temperature range instead of holding the temperature at a constant temperature.

  Between this preheating condition and the subsequent rapid annealing at a temperature of 300 ° C. or more and 480 ° C. or less may be carried out continuously or once cooled to room temperature.

  At this time, the required holding time in the temperature range of 150 ° C. to 220 ° C. is 1 hour to 24 hours, more preferably 180 ° C. to 220 ° C. for 2 hours to 22 hours, and the optimum range. Is 200 ° C. or more and 220 ° C. or less and 10 hours or more and 20 hours or less.

As another production method of the present invention, the purity of aluminum is 99.8% by mass or more, Si: 0.006% by mass to 0.05% by mass, Fe; 0.006% by mass to 0.00%. An aluminum material having a composition of 05% by mass or less, Cu; 0.0005% by mass or more and 0.03% by mass or less, Ga of 0.03% by mass or less, and other impurities of 0.02% by mass or less. After casting at a cooling rate of 1 × 10 ³ ° C./second or more and then cooling to form an aluminum plate, the range of 360 to 480 ° C. is retained for 1 second to 10 hours and then cooled. A characteristic method for producing an aluminum alloy material for electrolytic capacitors can be mentioned.

Similarly, other production methods include Si; 0.006 mass% to 0.05 mass%, Fe; 0.006 mass% to 0.05 mass%, Cu; 0.0005 mass% to 0.03 mass. An aluminum material having a composition of not more than%, Ga of 0.03% by mass or less, and other impurities of 0.02% by mass or less, respectively, at a cooling rate of 1 × 10 ³ ° C./second or more, A method for producing an aluminum alloy material for electrolytic capacitors, characterized in that after cooling to obtain an aluminum plate, final annealing is performed at a temperature of 260 ° C. or higher and 330 ° C. or lower for a time of 1 hour or more and 10 hours or less. Can do. In this case, prior to the final annealing, a heat treatment may be performed at a temperature of 220 ° C. to 250 ° C. for 1 hour to 5 hours.

Here, as a method of casting at a cooling rate of 1 × 10 ³ ° C./second or more and then cooling to obtain an aluminum plate (including strips), molten aluminum is continuously inserted between two cooling rolls. A continuous casting and rolling method for obtaining a sheet-like ingot can be mentioned. The more desirable range of the cooling rate when producing the continuously cast rolled material is 5 × 10 ³ ° C./second or more, and the optimum range is 1 × 10 ⁴ ° C./second or more.

  Moreover, it is desirable that the thickness of the continuously cast rolled material is 0.5 mm or more and 5 mm or less. If this continuous cast rolled material is thin, it is difficult to obtain a sufficient degree of cold work necessary to secure the crystal grain size at the time of final annealing, and if it is thick, the cooling rate necessary to control the subsequent intermetallic compound is not sufficient. It is difficult to secure enough. A more desirable range of the thickness of the continuously cast rolled material is 0.8 mm or more and 3 mm or less, and an optimum range is 0.9 mm or more and 2 mm or less.

Cold rolling may be performed by a conventional method, but the annealing satisfies the above relational expression, 0.0005 ≦ (I _Fe / C _Fe +3 I _Si / C _Si +5 I _Cu / C _Cu ) × C _Fe ≦ 0.015 As long as it is within the range, there is no problem with rapid annealing or batch annealing. Moreover, the cooling roll at the time of continuous cast rolling material preparation is made into a single roll, and satisfies 0.0005 ≦ (I _Fe / C _Fe +3 I _Si / C _Si +5 I _Cu / C _Cu ) × C _Fe ≦ 0.015 on one side. Even when a structure is obtained, there is no problem if only this surface is roughened by etching.

In the aluminum material according to the present invention manufactured using such a continuous casting and rolling method, each of Fe, Si, and Cu contained in the intermetallic compound in a region of 25% or more of the total thickness of the aluminum material Rate: between each mass% of I _Fe , I _Si , I _Cu and the content ratio of the whole material: 0.0005 ≦ (I _Fe / C _Fe +3 I _Si / C _Si between each mass% of C _Fe , C _Si , C _Cu + 5I _Cu / C _Cu ) × C _Fe ≦ 0.015 is established. Since the contact surface with the cooling roll is dissolved or the amount of precipitation as an intermetallic compound is small, a fine etching pattern can be formed in the subsequent etching process.

  The thickness of the region satisfying the above relationship (hereinafter referred to as the relational satisfaction region) may be 25% or more of the thickness of the entire aluminum material from the surface of the aluminum material. When the cooling roll is a single roll, as shown in FIG. 1, the relational expression sufficient area 2a is formed only on one side of the aluminum material 1 in contact with the cooling roll, and the thickness of the relational expression sufficient area 2a is The thickness t1 may be 25% or more of the thickness T of the aluminum material 1. When two cooling rolls are used, the relational expression sufficient areas 2a and 2b are formed on both sides of the aluminum material 1 as shown in FIG. 2, and the total thickness of these relational expression satisfaction areas 2a and 2b is formed. The thickness t1 + t2 may be 25% or more of the thickness T of the aluminum material 1.

  The aluminum material manufactured as described above is subjected to an etching process for improving the surface expansion ratio to obtain an electrode material for an electrolytic capacitor. Although the etching process conditions are not particularly limited, it is preferable to adopt the AC etching method at least partially. By the AC etching method, a spongy etching structure having a large area expansion ratio is generated, and a high capacitance is realized.

  In addition, when etching the aluminum material 1 in which the relational expression satisfaction area 2 is formed only on one side, by performing a process such as a mask on the surface on which the relational expression satisfaction area 2 is not formed, The relational satisfaction area 2 may be preferentially etched.

  After the etching treatment, it is desirable to perform a chemical conversion treatment to make an anode material, and in particular, it may be used as an electrolytic capacitor electrode material for low pressure or medium pressure, but it does not prevent its use as a cathode material. . Moreover, the electrolytic capacitor using this electrode material can realize a large capacitance.

[Examples 1 to 7, Comparative Examples 1 and 2]
Aluminum ingots (thickness: 400 mm) having various compositions with round numbers 1 to 9 shown in Table 1 were produced by a semi-continuous casting method.

  A 400 mm thick aluminum ingot having a composition selected from the aluminum ingots shown in Table 1 as shown in Table 2 was homogenized at 600 ° C. for 20 hours, and then face-cut to give 550 ° C. × 5 After heating for a period of time, hot rolling was performed to obtain a hot rolled plate having a thickness of 10 mm.

  Thereafter, cold rolling was continued to obtain an aluminum foil having a thickness of 0.095 mm. The foil was subjected to final annealing at 300 ° C. for 15 minutes. Table 2 shows the heating rate up to 300 ° C. In addition, about Example 7, it was made to stay for 5 hours in the temperature range of 200 degreeC prior to the last annealing.

About the aluminum material for electrolytic capacitors obtained in this way, an intermetallic compound was extracted and analyzed under the following conditions, and I _Fe / C _Fe +3 I _Si / C _Si +5 I _Cu / C _Cu ) × C _Fe was calculated.

  Subsequently, the electrostatic capacity was measured by performing etching and chemical conversion treatment under the following conditions.

The results are shown in Table 2. The capacitance is shown as a relative comparison with the capacitance of Comparative Example 2 as 100.
<Intermetallic compound extraction method and analysis method>
Insert the sample into the dehydrated phenol and heat. After the sample is completely decomposed, it is cooled to about 140 ° C. and benzyl alcohol is added. Suction filtration is performed using a 0.1 μm PTFE membrane filter, which is washed with benzyl alcohol and acetone to obtain a sample for analysis.

The residue collected on the PTFE membrane filter is dissolved in a mixed acid (hydrochloric acid + nitric acid) solution, and Fe is quantified with an ICP emission spectroscopic analyzer.
<Etching evaluation method>
Etching solution Etching treatment using hydrochloric acid 1.8mol / L + H ₂ SO ₄ 0.04mol / L, temperature 55 ° C, sine wave AC 30Hz, current density AC 0.3A / cm ² (single side), time 300 seconds went.

Furthermore, in an aqueous ammonium phosphate solution (1.5 g / L, 85 ° C.), it is subjected to a chemical conversion treatment at a current density of 5 mA / cm ² by a constant voltage conversion treatment of 20 V × 10 min, and heat treatment in an atmosphere of 500 ° C. × 5 min. After that, re-chemical conversion was performed for 5 minutes under the same conditions to form a dielectric oxide film.

As understood from the results in Table 2, the present invention products satisfying 0.0005 ≦ (I _Fe / C _Fe +3 I _Si / C _Si +5 I _Cu / C _Cu ) × C _Fe ≦ 0.015 (Examples 1 to It can be seen that 7) is superior in capacitance compared to comparative products (Comparative Examples 1 and 2) that depart from the above relationship.
[Examples 11 to 14, Comparative Examples 3 and 4]
A 400 mm-thick aluminum ingot having a composition selected from the aluminum ingots shown in Table 1 as shown in Table 3 was homogenized at 580 ° C. for 12 hours, and then subjected to face grinding. After heating at 0 ° C. for 5 hours, hot rolling was performed to obtain a hot rolled plate having a thickness of 10 mm.

  Thereafter, cold rolling was continued to obtain an aluminum foil having a thickness of 0.095 mm. The foil was subjected to final annealing at 300 ° C. for 15 minutes. Table 3 shows the heating rate up to 300 ° C.

About the aluminum material for electrolytic capacitors obtained in this way, an intermetallic compound was extracted and analyzed under the same conditions as in Examples 1 to 7, and I _Fe / C _Fe +3 I _Si / C _Si +5 I _Cu / C _Cu ) × C _Fe Calculated. In addition, the recrystallization rate was examined by the following method, and the average crystal grain size of the recrystallized grains and the area occupancy ratio of the cubic orientation grains measured from the foil surface among the recrystallized grains were also examined.

  Next, etching and chemical conversion treatment were performed under the same conditions as in Examples 1 to 7, and the capacitance was measured.

The results are shown in Table 3. The capacitance is shown by relative comparison with the capacitance of Comparative Example 2 in Table 2 as 100.
<Measurement method of recrystallization rate>
The surface of the aluminum material was polished with emery paper, subjected to rough buffing and finish polishing, and then washed with water and dried. Next, the surface of the polished aluminum material was anodized using a positive electrode. The anodizing treatment was performed using Barker's solution (3 ± 1% borohydrofluoric acid), bath temperature: 28 ± 1 ° C., applied voltage: 30 V, and applied time: 45 seconds. The anodized sample was observed with a polarizing microscope, and the percentage of clear recrystallized grains in the observation field was determined. The area of the observation visual field is not specified but is preferably 10 mm ² or more.
<Measuring method of average grain size>
The measurement was repeated a plurality of times by the method specified in JIS H0501 (cutting method of the grain size test method for copper products), and the average value was calculated.
<Measuring method of area occupancy of cube-oriented grains>
By performing chemical etching by immersing the aluminum foil in an etching solution having a volume ratio of 35% HCl: 60% HNO ₃ : 46% HF = 5: 5: 1 for 45 seconds, and adjusting reflection by the light source Measurement was performed by binarizing the obtained image.

As understood from the results shown in Table 3, 0.0005 ≦ (I _Fe / C _Fe +3 I _Si / C _Si +5 I _Cu / C _Cu ) × C _Fe ≦ 0.015, recrystallization rate of 60% or more, Products according to the present invention (Examples 11 to 14) satisfying an average crystal grain size of 30 μm or more and 400 μm or less and an area occupancy of 20% or less of cubic oriented grains are 0.0005 ≦ (I _Fe / C _Fe + 3I _Si / C _Si + 5I _Cu / C _Cu ) × C _Fe ≦ 0.015 It can be seen that the capacitance is superior to the comparative product (Comparative Examples 3 and 4) that deviates.
[Examples 21 to 29, Comparative Examples 5 and 6)
A plate material having a composition selected from the aluminum ingots shown in Table 1 as shown in Table 4 was prepared by a continuous casting and rolling method in which molten aluminum was continuously inserted between two cooling rolls. In the continuous casting and rolling method, both sides of the molten metal were brought into contact with a cooling roll. The ingot cooling rate at that time was as shown in Table 4.

  The obtained plate material was subsequently cold-rolled to obtain an aluminum foil having a thickness of 0.105 mm. The foil was finally annealed under the conditions shown in Table 4. In addition, about Example 29, the heat processing of 240 degreeC x 2 hours were given prior to the last annealing. Moreover, about Example 25 and 26, after the final annealing, additional rolling was performed with the rolling reduction shown in Table 4.

About the aluminum material for electrolytic capacitors obtained in this way, an intermetallic compound was extracted and analyzed under the same conditions as in Examples 1 to 7, and I _Fe / C _Fe +3 I _Si / C _Si +5 I _Cu / C _Cu ) × C _Fe Calculated. Moreover, the ratio which occupies for the thickness of the aluminum foil of the area | region which has the calculated value was measured.

  Next, etching and chemical conversion treatment were performed under the same conditions as in Examples 1 to 7, and the capacitance was measured.

  The results are shown in Table 4. The capacitance is shown by relative comparison with the capacitance of Comparative Example 2 in Table 2 as 100.

As understood from the results shown in Table 4, the product of the present invention in which 0.0005 ≦ (I _Fe / C _Fe +3 I _Si / C _Si +5 I _Cu / C _Cu ) × C _Fe ≦ 0.015 (Example 21) It can be seen that -29) are superior in capacitance compared to comparative products (Comparative Examples 5 and 6) that deviate from the above relationship.

It is sectional drawing of the aluminum material for electrolytic capacitors which concerns on one Embodiment of this invention. It is sectional drawing of the aluminum material for electrolytic capacitors which concerns on other embodiment of this invention.

Explanation of symbols

1 Aluminum material 2a, 2b Relational expression satisfaction area

Claims (14)

Si; 0.006 mass% or more and 0.05 mass% or less, Fe; 0.006 mass% or more and 0.05 mass% or less, Cu; 0.0005 mass% or more and 0.03 mass% or less, Each content of Fe, Si, and Cu contained in the intermetallic compound extracted by the hot phenol dissolution method with Ga of 0.03% by mass or less and other impurities of 0.02% by mass or less, respectively. 0.0005 ≦ (I _Fe) between each mass% of _Fe , I _Si , and I _{Cu and} each mass percentage of Fe, Si, and Cu contained in the whole material: C _Fe , C _Si , and C _Cu / C _Fe + 3I _Si / C _Si + 5I _Cu / C _Cu ) × C _Fe ≦ 0.015   The recrystallization rate is 60% or more, the average crystal grain size of the recrystallized grains is 30 μm or more and 400 μm or less, and the area occupancy ratio of the cubic orientation grains measured from the surface of the aluminum alloy material among the recrystallized grains The aluminum alloy material for electrolytic capacitors according to claim 1, wherein is less than 20%. In the region of 25% or more of the thickness of the aluminum material from the surface of the aluminum material, the respective contents of Fe, Si, and Cu contained in the intermetallic compound extracted by the hot phenol dissolution method: I _Fe , I _Si , Fe contained in the entire I _Cu each mass% and material, Si, each content of _{Cu: C Fe, C Si,} C Cu 0.0005 ≦ between each _{mass% (I Fe / C Fe +} 3I Si / C _Si + 5I _Cu / C _Cu ) × C _Fe ≦ 0.015   Si; 0.006 mass% or more and 0.05 mass% or less, Fe; 0.006 mass% or more and 0.05 mass% or less, Cu; 0.0005 mass% or more and 0.03 mass% or less, After cold-rolling an aluminum plate material having a Ga content of 0.03% by mass or less and other impurities of 0.02% by mass or less at a reduction rate of 60% or more, a temperature rise to 300 ° C. is increased to 10 ° C. during the heat treatment. The manufacturing method of the aluminum alloy material for electrolytic capacitors characterized by making it hold | maintain in the range of 300-480 degreeC for 1 second or more and 20 minutes or less, and making it cool after that.   5. The method for producing an aluminum alloy material for electrolytic capacitors according to claim 4, wherein the residence time in the temperature range from 150 ° C. to 220 ° C. is set to 1 hour to 24 hours in advance of the heat treatment.   6. The aluminum alloy material for electrolytic capacitors according to claim 4, wherein the aluminum material having a thickness of 80 μm to 150 μm after cooling is subjected to additional rolling at a rolling reduction of 5% to 30%. Production method. Si; 0.006 mass% or more and 0.05 mass% or less, Fe; 0.006 mass% or more and 0.05 mass% or less, Cu; 0.0005 mass% or more and 0.03 mass% or less, After casting an aluminum material having a Ga content of 0.03% by mass or less and other impurities of 0.02% by mass or less at a cooling rate of 1 × 10 ³ ° C./second or more and then cooling to obtain an aluminum plate material A method for producing an aluminum alloy material for electrolytic capacitors, wherein a temperature range of 360 to 480 ° C. is retained for 1 second to 10 hours and then cooled. Si; 0.006 mass% or more and 0.05 mass% or less, Fe; 0.006 mass% or more and 0.05 mass% or less, Cu; 0.0005 mass% or more and 0.03 mass% or less, After casting an aluminum material having a Ga content of 0.03% by mass or less and other impurities of 0.02% by mass or less at a cooling rate of 1 × 10 ³ ° C./second or more and then cooling to obtain an aluminum plate material A method for producing an aluminum alloy material for electrolytic capacitors, comprising performing final annealing at a temperature of 260 ° C. or higher and 330 ° C. or lower for a time of 1 hour or more and 10 hours or less.   The method for producing an aluminum alloy material for electrolytic capacitors according to claim 8, wherein a heat treatment is performed at a temperature of 220 ° C or higher and 250 ° C or lower for 1 hour or more and 5 hours or less prior to the final annealing.   The method for producing an aluminum alloy material for an electrolytic capacitor according to any one of claims 7 to 9, wherein the aluminum plate material is produced by casting at least one surface of a melt of a material to be subjected to cold rolling in contact with a cooling roll. .   The manufacturing method of the electrode material for electrolytic capacitors characterized by including the process of etching the aluminum alloy material of any one of Claim 1 thru | or 3.   The method for producing an electrode material for an electrolytic capacitor according to claim 11, wherein at least a part of the etching is AC etching.   The anode material for electrolytic capacitors manufactured by the manufacturing method of Claim 11 or 12.   An aluminum electrolytic capacitor characterized in that an aluminum electrode material produced by the production method according to claim 11 or 12 is used as the electrode material.

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