JP2009120963A - Manufacturing method of aluminum material for electrolytic capacitor electrode - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture an aluminum material for an electrolytic capacitor electrode, which has a thickness of 125-250 μm and is capable of achieving a high capacitance by achieving a high proportion of crystal grains with (100) plane orientation. <P>SOLUTION: An aluminum material which has an Al purity of ≥99.9 mass% and comprises 3-30 mass ppm Si, 3-18 mass ppm Fe, 5-70 mass ppm Cu and the balance being impurities is subjected to a homogenization treatment, subsequently subjected to a hot-rolling step of initiating rolling at material temperature of 500-610°C and performing rolling at a hot working rate of 97.5-99%, subsequently subjected to a cold-rolling step of performing rolling so that cold working rate R(%) and thickness T (μm) after cold-rolling satisfy the relation: -40R+4000≤T≤-100R+10000 (wherein 125≤T≤250) without performing intermediate annealing and subsequently subjected to final annealing. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing an aluminum material for an electrolytic capacitor anode.

  In this specification, the term “aluminum” is used to include both aluminum and its alloys.

  An aluminum material generally used as an electrode material for an aluminum electrolytic capacitor is usually subjected to an electrochemical or chemical etching treatment in order to increase the capacitance per unit area by expanding its effective area.

  In an anode material of a type that is subjected to tunnel type etching called high-pressure etching, the capacitance can be effectively increased by preferentially growing a cubic texture having a (100) plane orientation on the surface of the aluminum material. That is already known. In recent years, demands from users for high-pressure foils have become more severe, and it is required that the (100) plane orientation occupancy is always 90% or more.

  Some proposals have been made for such problems (Patent Documents 1 to 3).

  For example, Patent Document 1 (Japanese Patent Laid-Open No. 2001-73105) proposes a method of controlling the (100) plane orientation of a crystal by a manufacturing process. That is, homogenization treatment, hot rolling, primary cold rolling and intermediate annealing are performed on an ingot having an Al purity of 99.97% or more, and a (100) orientation in which the grain size is 10 μm or less in the plate thickness section. An aluminum thin plate is obtained in which the average number of crystal grains having the number is 2000 to 4700 / mm @ 2 and the average occupation ratio of crystal grains having the (100) orientation is 8 to 37%. The thin plate is subjected to 10-20% final cold rolling and subsequent final annealing.

  Patent Document 2 (Japanese Patent Laid-Open No. 10-189395) proposes that the content of P and Bi, which are inevitable impurities in a high-purity aluminum material, is regulated and the cube orientation occupation ratio is increased by the chemical composition of the alloy. .

  In recent years, with the miniaturization of products, the need for miniaturization of capacitors and high capacitance has increased, and proposals have been made from a viewpoint other than the above-described (100) plane occupancy. For example, in Patent Document 3 (Japanese Patent Laid-Open No. 3-122260), after removing oil adhering to the surface of an aluminum material and a non-uniform oxide film formed during rolling, a new oxide film is formed by heating at a high temperature. Thus, it has been proposed to control the oxide film structure and thickness to uniformly generate etching nuclei.

JP 2001-73105 A Japanese Patent Laid-Open No. 10-189395 Japanese Patent Laid-Open No. 3-122260

  In order to obtain a high capacitance, in addition to the above-mentioned efforts to control the (100) orientation and uniform etching nuclei, the thickness of the aluminum material is increased so that the etching pit length can be increased. There is also a way of thinking that achieves higher surface area and higher capacitance. For example, when aluminum material thickness: 100 μm foil and 200 μm foil are used as anodes and the volume increase rate of the anode part in the same volume of the electrolytic capacitor is considered (the etching density is the same for both, the core remaining part is the same) Assuming), the 200 μm foil has a capacitance improvement effect of about 30% compared to the 100 μm foil.

  According to the manufacturing methods described in Patent Documents 1 and 2 described above, if the aluminum material has a thickness of less than 125 μm, there is no generation of coarse grains after the final annealing, and the (100) plane orientation occupancy is 90% or more. It is possible to get things. However, when the aluminum material becomes thicker than 125 μm, the crystal grains become coarse after the final annealing, and the (100) plane orientation occupancy area ratio of 90% or more cannot be obtained. Capacitance cannot be realized.

  In this regard, Patent Document 1 discloses that hot rolling is performed under the condition of 99.2 to 99.8%, and then the cold working rate without performing intermediate annealing during the cold rolling. : A method of obtaining a high-purity aluminum material for an electrolytic capacitor having a thickness of 90 to 300 μm by performing cold rolling under conditions of 75.0 to 97.0% and performing final annealing is disclosed. However, in such hot rolling with a high processing rate, since the processing heat generation during rolling is too large, the temperature variation in the plate width direction during hot rolling becomes large, and the hot rolling having a uniform structure in the plate width direction. It was difficult to obtain a rolled sheet, and as a result, there was a problem that the final (100) plane orientation occupancy varied in the width direction.

  The present invention has been made from such background art, and even when the thickness is 125 to 250 μm, which is thicker than the conventional one, it suppresses the coarsening of crystal grains during the final annealing, and has a high level in the state after the etching treatment. It is an object of the present invention to provide an aluminum material for electrolytic capacitor electrodes having a certain capacitance, a manufacturing method thereof, and an electrolytic capacitor.

  In order to achieve the above object, as a result of intensive studies, the inventors have suppressed the coarsening of crystal grains even in a thick aluminum material having a thickness of 125 to 250 μm, and the (100) plane orientation occupation ratio is 90% or more. And succeeded in obtaining high capacitance.

That is, the present invention has the following configuration.
(1) An aluminum material having an Al purity of 99.9% by mass or more, Si: 3 to 30 ppm by mass, Fe: 3 to 18 ppm by mass, Cu: 5 to 70 ppm by mass, and the balance being impurities On the other hand, after performing the homogenization treatment, in the hot rolling step, the rolling starts at a material temperature of 500 ° C. to 610 ° C. and a hot working rate of 97.5 to 99%, In the cold rolling process, the cold working rate R (%) and the cold rolled thickness T (μm) are −40R + 4000 ≦ T ≦ −100R + 10000 (provided that 125 ≦ T ≦ 10000) without intermediate annealing. 250) A method for producing an aluminum material for electrolytic capacitor electrodes, wherein rolling is performed so as to satisfy the relationship 250), and final annealing is further performed.
(2) The aluminum material further includes one or more of Pb, In, Sn, and Sb in the chemical composition, and the total amount of these elements is 0.3 to 30 ppm by mass. The manufacturing method of the aluminum material for electrolytic capacitor electrodes as described in any one of.
(3) In the chemical composition, the aluminum material further contains one or more of Ga, Zn, Mn, Cr, Ti, Zr, and V, and Ga content / 10 and Zn content. / 10, The manufacturing method of the aluminum material for electrolytic capacitor electrodes of the preceding clause 1 or 2 whose sum total of Mn content, Cr content, Ti content, Zr content, and V content is 2-50 mass ppm.
(4) The aluminum material for an electrolytic capacitor electrode according to any one of the preceding items 1 to 3, wherein B, Mg, and Ni as impurities are regulated to a total amount of 12 mass ppm or less in a chemical composition. Production method.
(5) The manufacturing method of the aluminum material for electrolytic capacitor electrodes as described in any one of 1 to 4 above, wherein the hot rolling start temperature is 520 to 590 ° C.
(6) The manufacturing method of the aluminum material for electrolytic capacitor electrodes in any one of the preceding clauses 1-5 whose hot work rate is 98 to 99%.
(7) In the cold rolling step, rolling is performed so that the cold work rate R (%) and the thickness T (μm) after the cold rolling satisfy a relationship of −40R + 4010 <T <−100R + 9970. The manufacturing method of the aluminum material for electrolytic capacitor electrodes in any one of -6.

  According to the present invention, the electrolytic capacitor electrode has a thickness of 125 to 250 μm, a crystal grain size is defined, a (100) plane occupancy of 90% or more is ensured, and an oxide film thickness is defined. Aluminum material can be manufactured. As a result, it is possible to form an aluminum material which can form uniform and long etching pits by etching and can obtain a high and uniform capacitance.

  By using an aluminum material to which any one or more of Pb, In, Sn, and Sb is added in the present invention, an aluminum material that can obtain a higher electrostatic capacity by making the initial etching pit generation uniform can be manufactured.

  According to the aluminum material to which any one or more of Ga, Zn, Mn, Cr, Ti, Zr, and V are added in the present invention, the etching pit diameter is enlarged to improve the surface expansion ratio, and the higher capacitance. Can be produced.

  According to the aluminum material in which B, Mg, and Ni are regulated in the present invention, it is possible to manufacture an aluminum material that can obtain a higher capacitance by avoiding local pits.

  According to the optimization of the hot rolling start temperature in the present invention, precipitation of Fe and Si and seizure to the roll during rolling can be reliably avoided, and an aluminum material having excellent etching characteristics can be produced.

  According to the optimization of the hot rolling processing rate in the present invention, recrystallization occurs repeatedly, and variation in temperature is suppressed in the sheet width direction during rolling, so that it has a uniform and high (100) plane orientation occupation rate. Aluminum material can be manufactured.

  According to the optimization of the relationship between the cold efficiency and the thickness after the cold rolling in the present invention, the rolling texture is sufficiently developed and a high (100) plane orientation occupation ratio can be obtained with certainty.

It is a graph which shows the cold work rate range in the manufacturing method of the aluminum material for electrolytic capacitor electrodes of this invention.

  Below, the manufacturing method of the aluminum material for electrolytic capacitor electrodes of this invention and the aluminum material for electrolytic capacitor electrodes manufactured by this method are explained in full detail.

  In the manufacturing method of the aluminum material for electrolytic capacitor electrodes of the present invention, the chemical composition of the constituent material of the aluminum material, the thickness of the aluminum material, and the manufacturing process are defined.

  In the chemical composition, the constituent material of the aluminum material defines Al purity, Si, Fe, and Cu as essential components, and one or more of Pb, In, Sn, Sb as optional additional elements, or Ga, One or more of Zn, Mn, Cr, Ti, Zr, and V are added. Further, B, Mg, and Ni as impurities are regulated.

  Al purity shall be 99.9 mass% or more. When the purity is less than 99.9% by mass, the growth of etching pits is inhibited by many impurities during etching, and uniform long tunnel-type etching pits cannot be formed. Therefore, an aluminum material having a high capacitance can be obtained. It is not possible. Preferably, the Al purity is 99.95% by mass or more.

  Si is an element inevitably contained in the aluminum material. If the Si content is less than 3 mass ppm, it becomes easy to cause coarsening of crystal grains at the time of final annealing, and if it exceeds 30 mass ppm, the method in which the intermediate annealing is not performed as in the manufacturing method of the present invention, Since it is difficult to ensure 90% or more in the occupied area ratio of crystal grains having a (100) plane orientation (hereinafter abbreviated as (100) plane orientation occupied ratio), it is necessary to set it to 3 to 30 mass ppm. is there. The preferred Si content is 3 to 28 ppm by mass.

  Fe is an element inevitably contained in the aluminum material. If the Fe content is less than 3 ppm by mass, it tends to cause coarsening of crystal grains during final annealing, and if it exceeds 18 ppm by mass, Since it is difficult to ensure 90% or more in the (100) plane orientation occupancy by the method that does not perform the intermediate annealing as in the manufacturing method, it is necessary to set it to 3 to 18 ppm by mass. A preferable Fe content is 3 to 16 ppm by mass.

  Cu dissolves in the Al matrix, thereby increasing the solubility of the aluminum material to promote the growth of etching pits and increase the capacitance. If the Cu content is less than 5 ppm by mass, the above effect is poor. If the Cu content exceeds 70 ppm by mass, 90% or more in the (100) plane orientation occupancy can be secured by a method that does not perform intermediate annealing as in the production method of the present invention. Since it is difficult, it is necessary to set it as 5-70 mass ppm. A preferable Cu content is 10 to 60 ppm by mass.

  Pb, In, Sn, and Sb are concentrated on the surface of the aluminum material at the time of final annealing, uniformizing the initial etch pit generation, and suppressing the generation of local etch pits. The above effects can be obtained by containing at least one of these elements, and the same effect can be obtained by using two or more kinds in combination. When the total content of these elements is less than 0.3 ppm by mass, the above effect is poor, and when it exceeds 30 ppm by mass, the surface of the foil becomes solubilized and the capacitance decreases instead. Is preferable. A particularly preferable total content is 0.5 to 20 ppm by mass.

  Ga, Zn, Mn, Cr, Ti, Zr, and V have the effect of improving the chemical etching property, and are effective in increasing the etch pit diameter to increase the surface expansion ratio and improving the capacitance. The above effects can be obtained by containing at least one of these elements, and the same effect can be obtained by using two or more kinds in combination. In the above effect, Ga and Zn are equivalents, and Mn, Cr, Ti, Zr, and V are also equivalents. Since Ga and Zn have a larger solid solubility limit with respect to Al than Mn, Cr, Ti, Zr, and V, they are about 1/10 when the above effects are compared. Therefore, the content of these elements is evaluated as Ga and Zn equal to 1/10 of the content of other elements, Ga content / 10, Zn content / 10, Mn content, Cr content, Ti It is defined by the sum of content, Zr content, and V content. If the total of these is less than 2 ppm by mass, the above effect is poor, and if it exceeds 50 ppm by mass, over-dissolution occurs, so 2-50 ppm by mass is preferable. A particularly preferred range is 5 to 40 ppm by mass.

  B, Mg, and Ni are concentrated on the surface layer of the aluminum material at the time of final annealing, but are easily localized, and if they are large, they cause local pits. Therefore, the total amount of these elements as impurities is preferably regulated to 12 mass ppm or less. A particularly preferable upper limit is 8 mass ppm.

  The thickness (t) of the aluminum material is 125 to 250 μm. This is because a thin aluminum material having a thickness of less than 125 μm has little effect of improving the capacitance due to thickening. On the other hand, even if the thickness exceeds 250 μm, it becomes difficult to lengthen the pits by etching, so that the unetched portion becomes thick and the merit of increasing the capacity by increasing the thickness cannot be obtained. . A preferred thickness (t) is 200 to 250 μm.

  The aluminum material produced according to the present invention has a (100) plane orientation occupancy of 90% or more in the crystal structure of the surface. If it is less than 90%, long tunnel-type etching pits are not formed in the etching process, and a sufficient surface expansion rate cannot be obtained. A preferable (100) plane orientation occupation ratio is 95% or more.

  Regarding the crystal grains, the maximum crystal grain size is 1500 μm or less, and the average crystal grain size d (μm) satisfies the relationship of 70 ≦ d ≦ 2t + 200 with the above-described aluminum material thickness t (μm). It becomes. Presence of coarse crystal grains having a crystal grain size exceeding 1500 μm can be a non-uniform etching form in the etching process. In addition, the degree of growth of crystal grains increases as the thickness (t) of the aluminum material increases, and the average crystal grain size after final annealing increases. The average crystal grain size (d) of less than 70 μm is not feasible in a high-purity aluminum material having a thickness of 125 μm or more, and when it exceeds 2t + 200 (μm), the material within the unit used for etching, for example, the entire coil In this case, the risk of existence of coarse grains having a crystal grain size exceeding 1500 μm is not preferable. The preferable maximum particle size is 1200 μm or less, and the relationship between the preferable average crystal particle size d (μm) and the thickness t (μm) of the aluminum material is 70 ≦ d ≦ 2t.

  Further, the thickness of the oxide film existing on the surface of the aluminum material greatly affects the generation of etching pits in etching. When the thickness of the oxide film is less than 2 nm, surface dissolution occurs at the time of etching, the surface expansion ratio is lowered, and the capacitance becomes insufficient. On the other hand, when the thickness exceeds 8 nm, the insulating property of the oxide film becomes high, so that the etching property is lowered and the capacitance is lowered. Therefore, the oxide film thickness is 2 to 8 nm or less. A preferable oxide film thickness is 2 to 5 nm.

  The aluminum material for electrolytic capacitor electrodes manufactured according to the present invention is subjected to etching for improving the surface expansion ratio. The aluminum material is as thick as 125 to 250 μm in thickness (t), and the chemical composition, (100) plane orientation occupancy, crystal grain size, and oxide film thickness are controlled. Etching pits are formed. For this reason, an oxide film with a high withstand voltage is formed by chemical conversion treatment as an anode material. Moreover, it is suitable for an anode material in that it has a large effective area even if a voltage-resistant film is formed. Furthermore, since a high and uniform capacitance can be obtained at a high rated voltage, it is suitable for medium and high voltage electrolytic capacitor electrode materials. Moreover, the electrolytic capacitor using this electrode material can realize a large capacity.

  The aluminum material for electrolytic capacitor electrodes described above can be produced by the method of the present invention. Below, the manufacturing method is demonstrated in detail.

  First, a homogenization process is performed on the above-described aluminum material having a predetermined composition, for example, an aluminum ingot, and then hot rolling, cold rolling, and final annealing are sequentially performed.

In the hot rolling process, rolling is started when the material temperature is 500 to 610 ° C. When the hot rolling start temperature is lower than 500 ° C., Fe and Si are precipitated, which causes local etching. On the other hand, when the temperature is higher than 610 ° C., seizure to the roll occurs during rolling, which causes surface scratches. The hot working rate is 97.5 to 99%. The hot working rate R (%) is [(x ₀ −x ₀ ) / x, where x ₀ is the thickness of the aluminum material used for hot rolling and x ₁ is the thickness after hot rolling. ₀ ] × 100 (%). When the hot working rate is less than 97.5%, the number of passes of hot rolling is small and recrystallization does not occur repeatedly, so that a high (100) plane orientation occupation rate cannot be obtained. Since the reduction rate of one pass cannot be set too low to promote recrystallization, it is difficult to obtain a high (100) plane orientation occupancy even if the number of passes is increased at a low reduction rate. On the other hand, if the hot working rate exceeds 99%, the processing heat generation during rolling is too large, so the temperature variation in the plate width direction during hot rolling becomes large, and the hot working has a uniform structure in the plate width direction. It is difficult to obtain a rolled sheet, and the final (100) plane orientation occupancy varies in the width direction, which is not preferable. A preferable hot rolling start temperature is 520 to 590 ° C., and a preferable hot working rate is 98 to 99%.

In the cold rolling process, the cold working rate R (%) and the thickness T (μm) after the cold rolling are −40R + 4000 ≦ T ≦ −100R + 10000 (without intermediate annealing during the cold rolling) However, rolling is performed so as to satisfy the relationship of 125 ≦ T ≦ 250). FIG. 1 shows the relationship between the cold working rate (R)% and the thickness T (μm) after cold rolling in the present invention. When the cold work rate (R)% is lower than the above range, the rolling texture cannot be sufficiently developed, and a high (100) plane orientation occupation ratio cannot be obtained. When the cold work rate (R)% is higher than the above range, the hot rolled plate must be thickened to obtain the required cold work rate, and the structure of the hot rolled plate Control becomes difficult. Therefore, a high (100) plane orientation occupation rate cannot be obtained. The cold working rate (R) is [(y ₀ −T) / y, where y ₀ is the thickness of an aluminum plate subjected to cold rolling, and T is the thickness after cold rolling. ₀ ] × 100 (%). In the cold rolling step, a preferable relationship between the cold work rate R (%) and the thickness T (μm) after the cold rolling is −40R + 4010 <T <−100R + 9970.

  The reason why the intermediate annealing is not performed during the cold rolling is that, in the aluminum material having a thickness of 125 to 250 μm as in the present invention, the (100) plane occupancy is large, and the maximum crystal grain size and the average crystal grain size are the present invention. This is because a product satisfying the range may not be obtained.

  After the end of the cold rolling, the desired aluminum material for electrolytic capacitor electrodes is manufactured by performing final annealing. Since the thickness (T) after the cold rolling does not change even by the final annealing, it is substantially the final thickness of the aluminum material. Therefore, the aluminum material having a predetermined chemical composition is subjected to the above-described series of steps, in particular, a hot rolling step and a cold rolling step, so that even if the aluminum material has a thickness (t) of 125 to 250 μm, the final (100 ) Obtaining the aluminum material of the present invention having a high plane orientation occupation rate, no generation of coarse crystal grains having a grain size of 1500 μm or more, and an average crystal grain size d (μm) satisfying 70 ≦ d ≦ 2t + 200. it can.

  In the production of the aluminum material of the present invention, steps other than those described above, that is, dissolution / component adjustment / slab casting, soaking, final annealing of the aluminum material may be in accordance with conventional methods and should be particularly limited. There is no specification. Also, cleaning is performed as appropriate.

  The capacitance is measured in accordance with a conventional method, for example, by measuring an aluminum material that has been etched and subjected to chemical conversion treatment at 120 Hz with a platinum plate as a counter electrode in 30 g at 80 g / l ammonium borate. Just do it.

  Depending on the above, in the above-described aluminum material for electrolytic capacitor electrodes having a thickness of 125 to 250 μm, the crystal grain size is defined, and a (100) plane orientation occupation ratio of 90% or more is ensured, and the oxide film Since the thickness is regulated, uniform and long tunnel-type etching pits can be formed by etching. For this reason, uniform and high electrostatic capacity can be obtained.

  Further, by optimizing the Al purity, the formation of long etching pits is ensured by the growth of etching pits, and a higher capacitance can be obtained.

  Further, by optimizing the Si content, coarsening of crystal grains is suppressed, and a high (100) plane orientation occupancy can be obtained with certainty, and the capacitance can be increased.

  Further, by optimizing the Fe content, it is possible to reliably obtain a high (100) plane orientation occupancy without performing intermediate annealing and increase the capacitance.

  Further, according to the optimization of the Cu content in the present invention, the solubility is further increased, the growth of etching pits is promoted, and the capacitance can be increased.

  In addition, when one or more of Pb, In, Sn, and Sb are added, the initial etching pit generation is made uniform and a higher capacitance can be obtained.

  Moreover, according to the addition of one or more of Ga, Zn, Mn, Cr, Ti, Zr, and V, the etching pit diameter is enlarged, the surface expansion ratio is improved, and a higher capacitance can be obtained. it can.

  Further, according to the regulation of B, Mg, and Ni, it is possible to avoid a local pit and obtain a higher capacitance.

  Further, by optimizing the thickness of the aluminum material, the effect of increasing the capacitance by increasing the thickness can be obtained.

  Further, by optimizing the (100) plane occupancy, long tunnel-type etching pits are surely formed by etching, and the increase in capacitance is ensured.

  Further, by optimizing the maximum crystal grain size, uniform etching pits are reliably formed, and the increase in capacitance is ensured.

  Further, by optimizing the relationship between the average crystal grain size d and the thickness (t), uniform etching pits are reliably formed, and the increase in capacitance is ensured.

  In addition, a high and uniform capacitance can be obtained in the medium-high voltage anode material.

  In addition, an electrolytic capacitor using the aluminum material as an electrode material can be an electrolytic capacitor having a large and uniform capacitance.

  The aluminum material for electrolytic capacitor electrodes and the electrolytic capacitor produced by the present invention are not limited to those of the examples.

[Test 1: Aluminum material]
First, Examples No. 1-11, Nos. 21-41, Examples 46-69, Examples 71-93, Comparative Examples No. 12-20, Comparative Examples 42-45, Comparative Examples shown in Tables 1-4 70, comparative ingots 94 and 95 of aluminum ingots having various compositions were chamfered and homogenized at 600 ° C. for 10 hours. Subsequently, hot rolling and cold rolling were performed under different conditions to obtain a thickness (t) of 70 to 270 μm, and final annealing was performed to produce an aluminum material. The final annealing condition was 500 ° C. × 10 hours for each No ..

  About each aluminum material produced as mentioned above, the (100) plane orientation occupation rate, the maximum crystal grain size, the average crystal grain size, and the oxide film thickness were investigated by the following method.

  The (100) plane orientation occupancy and the maximum crystal grain size are obtained by immersing an aluminum material in a solution having a volume ratio of hydrochloric acid: nitric acid: hydrofluoric acid = 50: 47: 3 to reveal crystal grains, and image analysis apparatus Measured with In addition, about (100) plane orientation occupation rate, it was set as the average value of the both ends and center part of the width direction of an aluminum material.

  The average crystal grain size (d) is obtained by etching an aluminum material in a solution of borohydrofluoric acid: 3% under the conditions of voltage: 30 V and time: 1 minute to reveal crystal grains. It measured by the quadrature method (JIS H 0501).

  The oxide film thickness was measured by the Hunter Hall method (see M. S. Hunter and P. Fowle, J. Electrochem. Soc., 101 [9], 483 (1954)).

  These results are shown in Tables 1-4.

Next, after each aluminum material was immersed in an aqueous solution containing HCl: 1 mol / dm ³ and H ₂ SO ₄ : 3.5 mol / dm ³ at a liquid temperature of 75 ° C., the current density was 0.2 A / cm ² . Electrolytic treatment was performed. The aluminum material after the electrolytic treatment was further immersed in a hydrochloric acid-sulfuric acid mixed aqueous solution having the above composition at 90 ° C. for 360 seconds to obtain an etched aluminum material. The obtained aluminum material was subjected to chemical conversion treatment according to EIAJ standards at a chemical conversion voltage of 270 V to obtain an anode material, and the capacitance was measured. The results are shown in Tables 1 to 4 together with relative comparison when the capacitance of Comparative Example No. 20 is 100.

  From the results of Table 1, each example in which the composition, thickness, (100) plane orientation occupancy, maximum crystal grain size, average crystal grain size and oxide film thickness of the aluminum material are within the scope of the present invention is as follows. It was confirmed that the capacitance can be increased by etching as compared with the comparative example that departs from the scope of the present invention. In Comparative Examples No. 12, 14, and 16, coarse crystal grains of 1500 μm or more are generated after the final annealing, and in Comparative Examples No. 13, 15, 17, and 18, 90% or more cannot be secured in the (100) plane orientation occupation ratio. I understand that. Further, in Comparative Example No. 19, even when the aluminum material thickness is increased to 250 μm or more, the etch pits do not grow any further. Therefore, the capacitance is Example No. 10 (aluminum material thickness: 240 μm). It shows that there is no improvement even when compared.

  From the results in Table 2, it was confirmed that the capacitance could be further increased by adding a predetermined amount of Pb, In, Sn, Sb.

  From the results in Table 3, it was confirmed that the capacitance can be further increased by adding predetermined amounts of Ga, Zn, Mn, Cr, Ti, Zr, and V.

From the results in Table 4, it was confirmed that the capacitance can be further increased by regulating B, Mg, and Ni as impurities.
[Test 2: Method for producing aluminum material]
First, after chamfering aluminum ingots having various compositions A to J shown in Table 5, homogenization treatment was performed at 600 ° C. for 10 hours. Then, it hot-rolled on the conditions (material temperature at the time of a hot rolling start, hot work rate) shown to each No. of Table 6,7. Subsequently, cold rolling is performed at a cold working rate R (%) shown in Tables 6 and 7, the thickness after cold rolling (T) is set to 100 to 250 μm, and final annealing is performed to obtain an aluminum material. Produced. The final annealing condition was 500 ° C. × 10 hours for each No .. In this test, the thickness (T) after the cold rolling is the final aluminum material thickness.

  About each aluminum material produced as mentioned above, the (100) plane orientation occupation rate, the maximum crystal grain size, the average crystal grain size, and the oxide film thickness were examined by the same method as in Test 1. Further, regarding the (100) plane orientation occupancy, in addition to the average value in the width direction similar to that in Test 1, for the variation in the width direction, the difference between the end and the center is less than 3%. Judgment was carried out by making x of those. These results are shown in Tables 6 and 7.

  Next, each aluminum material was etched under the same conditions as in Test 1, and further subjected to chemical conversion to form an anode material, and the capacitance was measured. The results are shown in Table 6 by relative comparison when the capacitance of Comparative Example No. 122 is 100, and Table 7 is a comparative example of the same alloy (for example, Examples No. 125 and 126 are comparative examples). It shows by relative comparison when the electrostatic capacity of No.127) is 100.

  From the results of Tables 6 and 7, the aluminum material of each example prepared by using an aluminum material having a predetermined chemical composition and hot-rolling and cold-rolling under the conditions of the present invention to have a predetermined thickness is within the scope of the present invention. The (100) plane orientation occupancy is high and the variation in the width direction of the (100) plane orientation occupancy is small compared to the comparative example that deviates from. In each example, there is no generation of coarse crystal grains having a maximum crystal grain size exceeding 1500 μm, and the relationship between the average crystal grain size (d) and the thickness (t = T) is 70 ≦ d ≦ 2t + 200. It was satisfied and the oxide film was confirmed to be 2 to 5 nm. Moreover, it confirmed that the aluminum material of each Example can increase an electrostatic capacity by an etching compared with a comparative example.

  Note that Comparative Example Nos. 117 and 119 had large variations in capacitance because the variation in (100) plane orientation occupation ratio was large. Moreover, although the comparative example No. 124 obtained the electrostatic capacity equivalent to Example No. 100, since the start temperature of hot rolling was high, the surface generate | occur | produced the damage | wound and it was a defective product.

Claims (7)

  For an aluminum material having an Al purity of 99.9% by mass or more, containing Si: 3 to 30 ppm by mass, Fe: 3 to 18 ppm by mass, Cu: 5 to 70 ppm by mass, and the balance being impurities. After the homogenization treatment, in the hot rolling step, the rolling is started at a material temperature of 500 ° C. to 610 ° C. and the hot working rate is 97.5 to 99%, and then cold rolling. In the process, the cold working rate R (%) and the cold rolled thickness T (μm) are −40R + 4000 ≦ T ≦ −100R + 10000 (provided that 125 ≦ T ≦ 250) without intermediate annealing. The manufacturing method of the aluminum material for electrolytic capacitor electrodes characterized by performing rolling so that a relationship may be satisfy | filled, and also giving final annealing.   2. The aluminum material according to claim 1, wherein the aluminum material further contains one or more of Pb, In, Sn, and Sb in chemical composition, and the total amount of these elements is 0.3 to 30 ppm by mass. Manufacturing method of aluminum material for electrolytic capacitor electrodes.   The aluminum material further contains one or more of Ga, Zn, Mn, Cr, Ti, Zr, and V in chemical composition, and Ga content / 10, Zn content / 10, The method for producing an aluminum material for electrolytic capacitor electrodes according to claim 1 or 2, wherein the total of Mn content, Cr content, Ti content, Zr content, and V content is 2 to 50 ppm by mass.   The method for producing an aluminum material for electrolytic capacitor electrodes according to any one of claims 1 to 3, wherein the aluminum material is regulated such that B, Mg, and Ni as impurities are not more than 12 mass ppm in terms of chemical composition.   The method for producing an aluminum material for electrolytic capacitor electrodes according to any one of claims 1 to 4, wherein a hot rolling start temperature is 520 to 590 ° C.   The method for producing an aluminum material for electrolytic capacitor electrodes according to any one of claims 1 to 5, wherein the hot working rate is 98 to 99%.   In the cold rolling step, rolling is performed so that the cold working rate R (%) and the thickness T (µm) after the cold rolling satisfy a relationship of -40R + 4010 <T <-100R + 9970. The manufacturing method of the aluminum material for electrolytic capacitor electrodes in any one of these.

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