JP4603402B2 - Fine structure and manufacturing method thereof - Google Patents

Description

  The present invention relates to a microstructure having an aluminum layer having an anodized film on the surface with a plurality of micropores and a method for producing the same.

  In the technical fields of metal and semiconductor thin films, thin wires, dots, etc., the phenomenon of electrical, optical and chemical peculiarities can be seen by confining the movement of free electrons in a size smaller than a certain characteristic length. It has been known. Such a phenomenon is called “quantum mechanical size effect (quantum size effect)”. Research and development of functional materials applying such a unique phenomenon is being actively conducted. Specifically, a material having a structure finer than several hundred nm is referred to as a “microstructure” or “nanostructure”, and is one of the objects of material development.

  As a method for manufacturing such a fine structure, for example, a method for directly manufacturing a nano structure by a semiconductor processing technique including a fine pattern forming technique such as photolithography, electron beam exposure, and X-ray exposure can be given.

In particular, much research has been conducted on methods for producing nanostructures having a regular microstructure.
For example, as a method for forming a regular structure in a self-regulating manner, an anodized alumina film (anodized film) obtained by subjecting aluminum to an anodizing treatment in an electrolytic solution can be mentioned. It is known that a plurality of fine pores (micropores) having a diameter of about several nm to several hundred nm are regularly formed in the anodized film. By using this self-ordering of the anodized film and obtaining a perfectly regular arrangement, theoretically, hexagonal prism cells with a regular hexagonal bottom centered around the micropores are formed, and adjacent micropores are formed. It is known that the connecting line forms an equilateral triangle.
For example, Non-Patent Document 1 describes an anodized film having micropores. Non-Patent Document 2 describes that pores are spontaneously formed in the anodized film as the oxidation proceeds. Non-Patent Document 3 also proposes forming an Au dot array on a Si substrate using a porous oxide film as a mask.

  The greatest feature of the material of the anodic oxide film is that it adopts a honeycomb structure in which a plurality of micropores are formed in a direction substantially perpendicular to the substrate surface and in parallel at substantially equal intervals. In addition to this, the pore diameter, the pore interval, and the pore depth can be controlled relatively freely, which is a feature not found in other materials (see Non-Patent Document 3).

  As an application example of the anodized film, various devices such as nanodevices such as ultra-micro filters, magnetic devices such as high-density magnetic recording media, and light emitters are known. For example, in Patent Document 1, Co and Ni, which are magnetic metals, are filled in a micropore as a magnetic device, ZnO, which is a light emitting material, is filled in a micropore, and an enzyme / antibody is used as a biosensor in a micropore. Application examples such as filling inside are described.

Furthermore, in the field of biosensing, Patent Document 2 describes an example of using a structure in which a metal is filled in the micropores of an anodized film as a sample stage for Raman spectroscopic analysis.
In these practical applications, it is necessary to increase the area of the region where the ordered arrangement is maintained. If the period in which the regularity of the anodized film can be maintained is short, there is a problem that the performance as a fine structure cannot be exhibited.

  The present applicant discloses in Patent Document 3 that regularity can be improved by anodizing a chemically pure surface layer.

JP 2000-31462 A JP 2003-268592 A JP 2004-107770 A H. Masuda et. Al. , Jpn. J. et al. Appl. Phys. , Vol. 37 (1998), pp. L1340-1342, Part 2, No. 1 11A, 1 November 1998 (FIG. 2.) “Surface Technology Handbook”, edited by Surface Technology Association (1998), Nikkan Kogyo Shimbun, p. 490-553 Hideki Masuda, “Highly Ordered Metal Nanohole Array Based on Anodized Alumina”, Solid State Physics, 1996, Vol. 31, No. 5, p. 493-499

  However, the anodized film obtained by the prior art method has a short period in which regularity can be maintained in the anodized film even if the chemical purity of the material is increased, and the average size of the region where regularity called domain is maintained is It was difficult to make it larger than about 2 μm. FIG. 1 shows that two first domains 11 and 12 different domain domains 12 are recognized, as the micropores 5 and the cells 10 exist regularly, and the regularity thereof is indicated by two dotted lines. It is a schematic diagram which shows the surface of the aluminum substrate which has an anodic oxide film. Domains having a regular arrangement structure change depending on slight fluctuations in conditions during the anodizing process, transition in aluminum solids, lattice defects, and the like, so that a plurality of domains are formed on the aluminum surface. When using oxalic acid electrolyte in the anodizing step, the average domain size is about 0.5-1 μm, when using sulfuric acid electrolyte, it is 0.5 μm or less, and even when using phosphoric acid electrolyte, 2 μm is at most. It was a level.

When the inventors studied that foreign elements such as impurities are not detected in the domain region, the regularity of the domain can be improved by setting the hardness of the aluminum material before anodization to a specific value or less. The inventors have found that this is possible and have reached the present invention.
In order to obtain a structure having a regular large size domain by enlarging one region having regularity called a domain of an aluminum structure having an anodized film as much as possible, It was found that the domain of the anodized film can be finally expanded by controlling the hardness. Accordingly, an object of the present invention is to provide a microstructure comprising an aluminum plate with an oxide film having a large area, a low price, a large ordered area, and regularly arranged pores, and a method for producing the same. And

That is, the present invention provides the following (1) to (4).
(1) A microstructure in which micropores obtained by anodizing an aluminum plate having a Vickers hardness Hv of 20 or less are regularly arranged.
(2) The microstructure according to (1), wherein a step of holding at least once at 200 ° C. or more for 1 hour or more is performed before anodizing the aluminum plate.
(3) The microstructure according to (1) or (2), wherein the regularity of the micropore is an average domain size of 2 μm or more.
(4) A method for manufacturing a microstructure in which an aluminum plate is subjected to an anodizing treatment after being subjected to a heat treatment that is held at least once at 200 ° C. for 1 hour or more.

  The present invention provides a microstructure having a large region size in which a regularized structure is maintained and a method for manufacturing the same. In the microstructure of the present invention, the regular arrangement maintaining region per unit area becomes large, which leads to an improvement in yield when a device is obtained.

The present invention is described in detail below.
<Aluminum layer>
The structure of the present invention is an aluminum layer itself having an anodized film with micropores on its surface or a microstructure having at least a part of this layer.
The aluminum layer having an anodized film on the surface used in the present invention can be obtained by anodizing the aluminum surface.
The aluminum surface may be any surface as long as it is a member having an aluminum layer. For example, an aluminum substrate such as a substrate obtained by depositing high-purity aluminum on low-purity aluminum (for example, recycled material); silicon wafer, quartz, A substrate in which the surface of glass or the like is coated with high-purity aluminum by a method such as sputtering, vapor deposition, CVD, electrodeposition, chemical plating, or electroplating; an aluminum layer is placed on a metal or resin substrate via an adhesive layer A laminated substrate may be mentioned. The whole may be an aluminum plate.

  As will be described later, in the case of forming a depression that is the starting point of the present anodizing treatment by the self-ordering method, an aluminum plate is preferable because the member itself having an aluminum layer needs a certain thickness. In the following description, an aluminum plate that is an example of an aluminum layer will be used.

<Aluminum plate (rolled aluminum)>
The microstructure of the present invention can be made into an aluminum plate using a known aluminum material. The aluminum plate used in the present invention is a metal whose main component is dimensionally stable aluminum, and is made of aluminum or an aluminum alloy. In addition to a pure aluminum plate, an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements can also be used.

  In the present specification, various substrates made of the above-described aluminum or aluminum alloy are collectively referred to as an aluminum plate. Examples of foreign elements that may be contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The purity of aluminum is preferably 99.5% or more, and particularly preferably the Si content is 0.01% by mass or less. This is because Si is an element that easily precipitates, and depending on the conditions of heat treatment, it may cause crystal grain boundaries and reduce the domain size. More preferably, the aluminum purity is 99.9% by mass or more, and further preferably 99.99% by mass or more. When the aluminum purity is within the above range, the regularity of the micropore arrangement is improved.

  In order to use an aluminum alloy as a plate material, for example, the following method can be employed. First, a molten aluminum alloy adjusted to a predetermined alloy component content is subjected to a cleaning process and cast according to a conventional method. In the cleaning process, in order to remove unnecessary gas such as hydrogen in the molten metal, flux treatment, degassing process using argon gas, chlorine gas, etc., so-called rigid media filter such as ceramic tube filter, ceramic foam filter, A filtering process using a filter that uses alumina flakes, alumina balls or the like as a filter medium, a glass cloth filter, or a combination of a degassing process and a filtering process is performed.

  These cleaning treatments are preferably performed in order to prevent defects caused by foreign matters such as non-metallic inclusions and oxides in the molten metal and defects caused by gas dissolved in the molten metal. Regarding filtering of the molten metal, JP-A-6-57432, JP-A-3-162530, JP-A-5-140659, JP-A-4-231425, JP-A-4-276031, JP-A-5-311261, JP-A-5-311261 6-136466 and the like. Further, the degassing of the molten metal is described in JP-A-5-51659, Japanese Utility Model Laid-Open No. 5-49148, and the like. The applicant of the present application has also proposed a technique relating to degassing of molten metal in Japanese Patent Application Laid-Open No. 7-40017.

Next, casting is performed using the molten metal that has been subjected to the cleaning treatment as described above. Regarding the casting method, there are a method using a solid mold typified by a DC casting method and a method using a driving mold typified by a continuous casting method.
In DC casting, solidification occurs at a cooling rate of 0.5 to 30 ° C./second. When the temperature is less than 1 ° C., many coarse intermetallic compounds may be formed. When DC casting is performed, an ingot having a thickness of 300 to 800 mm can be produced. The ingot is chamfered as necessary according to a conventional method, and usually 1 to 30 mm, preferably 1 to 10 mm, of the surface layer is cut. Before and after that, soaking treatment is performed as necessary. When performing the soaking process, heat treatment is performed at 450 to 620 ° C. for 1 to 48 hours so that the intermetallic compound does not become coarse. If the heat treatment is shorter than 1 hour, the effect of soaking may be insufficient.

  Then, hot rolling and cold rolling are performed to obtain a rolled aluminum plate. An appropriate starting temperature for hot rolling is 350 to 500 ° C. An intermediate annealing treatment may be performed before or after hot rolling or in the middle thereof. The conditions for the intermediate annealing treatment are heating at 280 to 600 ° C. for 2 to 20 hours, preferably 350 to 500 ° C. for 2 to 10 hours using a batch annealing furnace, or 400 to 600 ° C. using a continuous annealing furnace. Heating is performed for 6 minutes or less, preferably 450 to 550 ° C. for 2 minutes or less. The crystal structure can be made finer by heating at a heating rate of 10 to 200 ° C./second using a continuous annealing furnace.

  The flatness of the aluminum plate finished to a predetermined thickness, for example, 0.1 to 0.5 mm by the above steps may be further improved by a correction device such as a roller leveler or a tension leveler. The flatness may be improved after the aluminum plate is cut into a sheet shape, but in order to improve productivity, it is preferably performed in a continuous coil state. Further, a slitter line may be used for processing into a predetermined plate width. Moreover, in order to prevent generation | occurrence | production of the damage | wound by friction between aluminum plates, you may provide a thin oil film on the surface of an aluminum plate. As the oil film, a volatile or non-volatile film is appropriately used as necessary.

  On the other hand, as the continuous casting method, a twin roll method (hunter method), a method using a cooling roll represented by the 3C method, a twin belt method (Hasley method), a cooling belt or a cooling block represented by the Al Swiss Caster II type The method using is industrially performed. When the continuous casting method is used, it solidifies at a cooling rate of 100 to 1000 ° C./second. Since the continuous casting method generally has a higher cooling rate than the DC casting method, it has a feature that the solid solubility of the alloy component in the aluminum matrix can be increased. Regarding the continuous casting method, the techniques proposed by the applicant of the present application are disclosed in JP-A-3-79798, JP-A-5-201166, JP-A-5-156414, JP-A-6-262203, and JP-A-6-122949. JP-A-6-210406 and JP-A-6-26308.

  When continuous casting is performed, for example, if a method using a cooling roll such as a Hunter method is used, a cast plate having a thickness of 1 to 10 mm can be directly cast continuously, and the hot rolling step is omitted. The advantage of being able to In addition, when a method using a cooling belt such as the Husley method is used, a cast plate having a thickness of 10 to 50 mm can be cast. Generally, a hot rolling roll is arranged immediately after casting and continuously rolled. Thus, a continuous cast and rolled plate having a thickness of 1 to 10 mm is obtained.

  These continuous cast and rolled plates are subjected to processes such as cold rolling, intermediate annealing, improvement of flatness, slits, and the like in the same manner as described for DC casting. Finished to a thickness of 5 mm. As for the intermediate annealing conditions and the cold rolling conditions when using the continuous casting method, the techniques proposed by the applicant of the present application are disclosed in JP-A-6-220593, JP-A-6-210308, JP-A-7-54111, It is described in JP-A-8-92709.

  The crystal structure of the aluminum plate may cause poor surface quality when the surface of the aluminum plate is subjected to chemical or electrochemical surface roughening. It is preferably not too coarse. The crystal structure on the surface of the aluminum plate preferably has a width of 200 μm or less, more preferably 100 μm or less, still more preferably 50 μm or less, and the length of the crystal structure is 5000 μm or less. Is preferably 1000 μm or less, and more preferably 500 μm or less. With regard to these, techniques proposed by the applicant of the present application are described in Japanese Patent Laid-Open Nos. 6-218495, 7-39906, and 7-124609.

There is a proportional relationship between the Vickers hardness of the aluminum substrate and the tensile strength of the aluminum, and in the case of a rolled material, the hardness can be generally controlled by adjusting the tensile strength. This tensile strength can be adjusted by cold working, solution treatment, age hardening, annealing, etc., in the process of obtaining the aluminum plate. The change in strength due to annealing is also described in aluminum handbooks.
Aluminum alloy composition also has an effect on strength. A 7000 series alloy containing Zn and Mg has a strength comparable to that of carbon steel, but a high purity 1000 series alloy shows only about 1/10 of the strength.
In the present invention example, the aluminum material is not limited to the rolled material. The present invention can also be applied to an aluminum layer provided by a method such as hot dipping or vapor deposition. Annealing treatment can reduce the hardness to release residual stress in the material.

<Heat treatment process>
In the present invention, before anodizing the aluminum plate as shown above, if a heat treatment step of holding at 200 ° C. or higher for 1 hour or longer is performed at least once, the grain boundaries present in the aluminum layer are reduced, As a result, a microstructure having an anodized film having a large domain size can be obtained. It is also preferable to carry out at 200 ° C. for 2 or 3 hours, preferably 250 ° C. for 1, 2, 3 hours, more preferably 300 to 400 ° C. for 1, 2, 3 hours. It may be carried out twice at 250 ° C. for 2 hours each and twice at 300 ° C. for 2 hours each. When the region having a high regularity of the pore arrangement is widened by the heat treatment, the sensing light reaches the detector without being irregularly reflected, so that the measurement accuracy is increased. The aluminum substrate after the heat treatment may be cooled by a method of directly adding it to water or the like, but is preferably naturally cooled.
In particular, when the heat treatment is performed in a suitable state within the above range, the average domain size after anodization can be easily set to 2 μm or more.

  The aluminum substrate is preferably subjected to a degreasing treatment and a mirror finishing treatment in advance.

<Degreasing treatment>
Degreasing treatment uses acids, alkalis, organic solvents, etc. to dissolve and remove organic components such as dust, fat, and resin that adhere to the aluminum surface, and causes defects in each treatment described later due to the organic components. This is done for the purpose of preventing the occurrence of.
A conventionally known degreasing agent can be used for the degreasing treatment. Specifically, for example, various commercially available degreasing agents can be used by a predetermined method.

Especially, the following each method is illustrated suitably.
A method in which an organic solvent such as various alcohols (for example, methanol), various ketones, benzine, and volatile oil is brought into contact with the aluminum surface at room temperature (organic solvent method); a solution containing a surfactant such as soap or neutral detergent at room temperature A method of bringing the aluminum surface into contact with the aluminum surface at a temperature of from 80 to 80 ° C., and then washing with water (surfactant method); A method of contacting and then washing with water; a direct current having a current density of 1 to 10 A / dm ² with a sodium hydroxide aqueous solution having a concentration of 5 to 20 g / L being brought into contact with the aluminum surface at room temperature for about 30 seconds, with the aluminum surface serving as a cathode. And then neutralizing by contacting with an aqueous nitric acid solution having a concentration of 100 to 500 g / L; various known anodizing treatment electrodes While in contact with the aluminum surface a liquid at room temperature, the aluminum surface by applying a direct current of a current density of 1 to 10 A / dm ² in the cathode, or a method of electrolysis by passing an alternating current; concentration 10 to 200 g / L A method in which an aqueous alkali solution is brought into contact with an aluminum surface at 40 to 50 ° C. for 15 to 60 seconds and then neutralized by bringing a nitric acid aqueous solution having a concentration of 100 to 500 g / L into contact; surfactant, water, etc. are added to light oil, kerosene, etc. A method in which the mixed emulsion is brought into contact with the aluminum surface at a temperature from room temperature to 50 ° C. and then washed with water (emulsion degreasing method); a mixed solution of sodium carbonate, phosphates, surfactant, etc. The aluminum surface is brought into contact with the aluminum surface for 30 to 180 seconds at a temperature up to and thereafter washed with water (phosphate method).

  The degreasing treatment is preferably a method in which the fat content on the aluminum surface can be removed while aluminum dissolution hardly occurs. In this respect, the organic solvent method, the surfactant method, the emulsion degreasing method, and the phosphate method are preferable.

<Mirror finish processing>
The mirror finishing process is performed to eliminate unevenness on the surface of the aluminum substrate and improve the uniformity and reproducibility of the particle forming process by an electrodeposition method or the like. As an unevenness | corrugation of the surface of an aluminum base material, the rolling rebar generated at the time of rolling in the case where an aluminum substrate is manufactured through rolling is mentioned, for example. The purpose is to improve the uniformity during the pre-anodizing treatment by eliminating the unevenness of the aluminum surface.
In the present invention, the mirror finish is not particularly limited, and a conventionally known method can be used. Examples thereof include mechanical polishing, chemical polishing, and electrolytic polishing.
Examples of the mechanical polishing include a method of polishing with various commercially available polishing cloths, and a method of combining various commercially available abrasives (for example, diamond, alumina) and a buff. Specifically, a method in which the method using an abrasive is performed by changing the abrasive used from coarse particles to fine particles over time is preferably exemplified. In this case, the final polishing agent is preferably # 1500. Thereby, the glossiness can be 50% or more (in the case of rolled aluminum, both the rolling direction and the width direction are 50% or more).

As chemical polishing, for example, “Aluminum Handbook”, 6th edition, edited by Japan Aluminum Association, 2001, p. Various methods described in 164 to 165 may be mentioned.
Further, phosphoric acid - nitric acid method, Alupol I, Alupol V, Alcoa R5, H 3 PO 4 -CH 3 COOH-Cu _{method, H 3 PO 4 -HNO 3 -CH} 3 COOH method are preferable. Among these, the phosphoric acid-nitric acid method, the H ₃ PO ₄ —CH ₃ COOH—Cu method, and the H ₃ PO ₄ —HNO ₃ —CH ₃ COOH method are preferable.
By chemical polishing, the glossiness can be made 70% or more (in the case of rolled aluminum, both the rolling direction and the width direction are 70% or more).

As electrolytic polishing, for example, “Aluminum Handbook”, 6th edition, edited by Japan Aluminum Association, 2001, p. Various methods described in 164 to 165 may be mentioned.
Moreover, the method described in US Pat. No. 2,708,655 is preferable.
“Practical Surface Technology”, vol. 33, no. 3, 1986, p. The method described in 32-38 is also preferably exemplified.
By electropolishing, the gloss can be 70% or more (in the case of rolled aluminum, both the rolling direction and the width direction are 70% or more).

Further, a CMP (Chemical-Mechanical-Planarization) method used for LSI processing or the like can also be suitably used.

  These methods can be used in appropriate combination. For example, a method of using an abrasive is preferably performed by changing the abrasive to be used from coarse particles to fine particles over time, and then performing electrolytic polishing.

By mirror finishing, for example, a surface having an average surface roughness R _{a of} 0.1 μm or less and a glossiness of 50% or more can be obtained. The average surface roughness _Ra is preferably 0.03 μm or less, and more preferably 0.02 μm or less. Further, the glossiness is preferably 70% or more, and more preferably 80% or more.
The glossiness is a regular reflectance obtained in accordance with JIS Z8741-1997 “Method 3 60 ° Specular Gloss” in the direction perpendicular to the rolling direction. Specifically, using a variable angle gloss meter (for example, VG-1D, manufactured by Nippon Denshoku Industries Co., Ltd.), when the regular reflectance is 70% or less, the incident reflection angle is 60 degrees and the regular reflectance is 70%. In the case of exceeding, the incident / reflection angle is 20 degrees.

<Indentation formation (pre-anodizing treatment)>
Before the anodizing treatment (hereinafter also referred to as “the present anodizing treatment”) for forming the micropores on the aluminum base material, it is preferable to form a depression that is the starting point for the generation of the micropores in the present anodizing treatment. .

  The method for forming the depression is not particularly limited, and examples thereof include a self-ordering method using the self-ordering property of the anodized film, a physical method, a particle beam method, a block copolymer method, and a resist interference exposure method.

<Self-regulation method>
The self-ordering method is a method of improving the regularity by utilizing the property that the micropores of the anodized film are regularly arranged and removing the factors that disturb the regular arrangement. Specifically, high-purity aluminum is used, and an anodized film is formed at a low speed over a long period of time (for example, several hours to several tens of hours) at a voltage corresponding to the type of electrolyte, and then removed. Perform membrane treatment.
In this method, since the pore diameter depends on the voltage, a desired pore diameter can be obtained to some extent by controlling the voltage.

  As a representative example of the self-ordering method, J.A. Electrochem. Soc. Vol. 144, no. 5, May 1997, p. L128 (Non-Patent Document 6), Jpn. J. et al. Appl. Phys. Vol. 35 (1996) Pt. 2, no. 1B, L126 (Non-patent Document 7), Appl. Phys. Lett, Vol. 71, no. 19, 10 Nov 1997, p. 2771 (Non-Patent Document 8) and Non-Patent Document 1 are known. Specifically, the self-ordering method is performed under the conditions shown below.

0.3 mol / L sulfuric acid, 0 ° C., 27 V, 450 minutes (Non-patent Document 6)
0.3 mol / L sulfuric acid, 10 ° C., 25 V, 750 minutes (non-patent document 6)
0.3 mol / L oxalic acid, 17 ° C., 40 V, 600 minutes; then pore wide treatment (6 wt% phosphoric acid and 1.8 wt% chromic acid-containing solution, 60 ° C., 840 minutes) (Non-patent Document 7)
0.3 mol / L oxalic acid, 17 ° C., 40-60 V, 36 minutes; then pore-wide treatment (5 wt% phosphoric acid, 30 ° C., 70 minutes) (Non-patent Document 8)
0.04 mol / L oxalic acid, 3 ° C., 80 V, film thickness 3 μm; then pore-wide treatment (5 wt% phosphoric acid, 30 ° C., 70 minutes) (Non-patent Document 8)
0.3 mol / L phosphoric acid, 0 ° C., 195 V, 960 minutes; then pore wide treatment (10 wt% phosphoric acid, 240 minutes) (Non-patent Document 1)

Further, in the methods described in these known documents, the film removal treatment for dissolving and removing the anodic oxide film takes 12 hours or more using a mixed aqueous solution of chromic acid and phosphoric acid at about 50 ° C. Yes. In addition, since the starting point of ordering will be destroyed and disturb | disturbed if it processes using the boiled aqueous solution, it uses without boiling.
Since the regularity of the self-ordered anodic oxide film becomes higher as it gets closer to the aluminum part, the film is removed once, and the bottom part of the anodic oxide film remaining on the aluminum part is exposed to the surface to form regular depressions. obtain. Therefore, in the film removal treatment, aluminum is not dissolved, but only the anodized film that is aluminum oxide is dissolved.

  The self-ordered anodizing treatment used in the present invention may be, for example, a method of energizing an aluminum substrate as an anode in a solution having an acid concentration of 1 to 10% by mass. As a solution used for the anodizing treatment, sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, amidosulfonic acid and the like can be used alone or in combination of two or more.

The conditions of the self-ordering anodizing treatment cannot be determined unconditionally because they vary depending on the electrolyte used. In general, the electrolyte concentration is 1 to 10% by mass, the solution temperature is 0 to 20 ° C., and the current density. It is appropriate that the pressure is 0.1 to 10 A / dm ² , the voltage is 10 to 200 V, and the electrolysis time is 2 to 20 hours.
The film thickness of the self-ordered anodic oxide film is preferably 10 to 50 μm.

In the present invention, the self-ordering anodizing treatment is preferably 1 to 16 hours, more preferably 2 to 12 hours, and further preferably 2 to 7 hours.
The film removal treatment is preferably 0.5 to 10 hours, more preferably 2 to 10 hours, and further preferably 4 to 10 hours.

  Thus, after forming the anodic oxide film by the self-ordering method, it is dissolved (defilming treatment) and removed, and when the anodic oxidation process described later is performed again under the same conditions, it is almost straight. Micropores are formed substantially perpendicular to the film surface.

<Physical method>
Examples of the physical method include a method using press patterning. Specifically, a method of forming a depression by pressing a substrate having a plurality of protrusions on the surface thereof against the aluminum surface can be mentioned. For example, a method described in JP-A-10-121292 can be used.
Another example is a method in which polystyrene spheres are arranged in a dense state on the aluminum surface, SiO ₂ is vapor-deposited thereon, then the polystyrene spheres are removed, and the substrate is etched using the vapor-deposited SiO ₂ as a mask to form depressions. It is done.

<Particle beam method>
The particle beam method is a method in which a hollow is formed by irradiating the aluminum surface with a particle beam. The particle beam method has an advantage that the position of the depression can be freely controlled.
Examples of the particle beam include a charged particle beam, a focused ion beam (FIB), and an electron beam.
As the particle beam method, for example, a method described in JP-A-2001-105400 can be used.

<Block copolymer method>
The block copolymer method is a method in which a block copolymer layer is formed on an aluminum surface, a sea-island structure is formed in the block copolymer layer by thermal annealing, and then an island portion is removed to form a depression.
As a block copolymer method, the method described in Unexamined-Japanese-Patent No. 2003-129288 can be used, for example.

<Resist interference exposure method>
The resist interference exposure method is a method in which a resist is provided on an aluminum surface, and the resist is exposed and developed to form a recess penetrating to the aluminum surface in the resist.
As the resist interference exposure method, for example, a method described in JP 2000-315785 A can be used.

Among the methods for forming the various depressions described above, the self-ordering method, the FIB method, and the resist interference exposure method are desirable because they can be uniformly formed over a large area of about 10 cm square or more.
Furthermore, the self-ordering method is most preferable in consideration of manufacturing costs. The FIB method is also preferable in that the arrangement of micropores can be freely controlled.

  The depth of the depression formed is preferably about 10 nm or more. The width is preferably equal to or less than the desired pore diameter.

<Book (main) anodizing treatment>
As described above, preferably, after forming a depression on the aluminum surface, an anodized film in which micropores are present is formed by the present anodizing treatment.
In the present anodizing treatment, conventionally known conditions can be applied, but in order to obtain a regular arrangement, the following conditions are preferable.
The concentration of the electrolytic solution is preferably 0.01 to 1 mol / L, and more preferably 0.1 to 0.5 mol / L. The temperature of the electrolytic solution is preferably 0 to 20 ° C, and more preferably 0 to 18 ° C. The electrolytic voltage can be appropriately selected according to a desired pore interval and pore diameter, but is preferably a voltage calculated by the following formula (1) or (2).

Voltage [V] = (Basic period [nm] −13) /2.5 [nm / V] (1)
Voltage [V] = (desired pore diameter [nm] −12) /0.6 [nm / V] (2)

  In the above formula, “basic period” means the distance between the centers of adjacent micropores.

  The above conditions are described in Masuda, Material Technology, 1997, Vol. 15, No. 10, p. 342.

Moreover, when using the method of surface-treating after forming an anodized film, it is also one of the preferable aspects that it is performed on the same conditions as the self-ordering method mentioned above.
Furthermore, a method of repeatedly turning on and off the current intermittently while keeping the DC voltage constant, and a method of repeatedly turning on and off the current while intermittently changing the DC voltage can be suitably used. According to these methods, fine micropores are generated in the anodized film.
In the above-described method of intermittently changing the voltage, it is preferable to decrease the voltage sequentially. Thereby, the resistance of the anodized film can be lowered.

When this anodizing treatment is performed at a low temperature, the arrangement of the micropores becomes regular and the pore diameter becomes uniform.
The film thickness of the anodized film is preferably 0.5 to 10 times the pore diameter, more preferably 1 to 8 times, and more preferably 1 to 5 times in terms of ease of particle formation treatment. Further preferred.
Therefore, for example, it is one of preferred embodiments that the film thickness of the anodized film is 0.1 to 1 μm and the average pore diameter of the micropores is 0.01 to 0.5 μm.

<Elution treatment>
The process of enlarging the micropores by eluting the aluminum oxide that forms the anodized film is referred to as pore-wide process. After this anodizing treatment, the aluminum substrate is immersed in an aqueous acid solution or an aqueous alkali solution to dissolve the anodized film and enlarge the pore diameter of the micropores.

When an aqueous acid solution is used for the pore wide treatment, it is preferable to use an aqueous solution of an inorganic acid such as sulfuric acid, phosphoric acid, nitric acid, hydrochloric acid, or a mixture thereof. The concentration of the acid aqueous solution is preferably 1 to 10% by mass. The temperature of the acid aqueous solution is preferably 25 to 40 ° C.
When an alkaline aqueous solution is used for the pore-wide treatment, it is preferable to use an aqueous solution of at least one alkali selected from the group consisting of sodium hydroxide, potassium hydroxide and lithium hydroxide. The concentration of the alkaline aqueous solution is preferably 0.1 to 5% by mass. The temperature of the alkaline aqueous solution is preferably 20 to 35 ° C.
Specifically, for example, 50 g / L, 40 ° C. phosphoric acid aqueous solution, 0.5 g / L, 30 ° C. sodium hydroxide aqueous solution or 0.5 g / L, 30 ° C. potassium hydroxide aqueous solution is preferably used. .
The immersion time in the acid aqueous solution or the alkali aqueous solution is preferably 8 to 60 minutes, more preferably 10 to 50 minutes, and further preferably 15 to 30 minutes.

After the pore-wide treatment, the average pore diameter of the micropores is preferably 10 to 500 nm, more preferably 15 to 450 nm, and still more preferably 20 to 400 nm. Further, after the pore-wide treatment, the pore diameter variation coefficient is preferably 10 to 80%. In addition, after the pore-wide treatment, the average pore density of the micropores is preferably 50 to 1500 / μm ² .

  A hydrophilization or hydrophobization treatment may be performed for the subsequent treatment after the anodization treatment or elution treatment. The purpose of the hydrophilization treatment is to impart wettability to treatment liquids (plating solution, electrolytic solution, coating solution, etc.) mainly for later various treatments, and to achieve more uniform treatment in the later treatment. Hydrophobic treatment has the effect of preventing contamination from atmospheres such as solutions and air.

  The hydrophilization treatment is not particularly limited in its method. For example, the treatment with potassium fluorinated zirconate described in US Pat. No. 2,946,638, US Pat. No. 3,201,247 The described phosphomolybdate treatment, the alkyl titanate treatment described in British Patent No. 1,108,559, the polyacrylic acid treatment described in German Patent No. 1,091,433, Polyvinylphosphonic acid treatment described in Japanese Patent No. 1,134,093 and British Patent No. 1,230,447, phosphonic acid treatment described in Japanese Patent Publication No. 44-6409, US Phytic acid treatment described in Japanese Patent No. 3,307,951, described in JP-A-58-16893 and JP-A-58-18291 Treatment with a salt of a lipophilic organic polymer compound and a divalent metal, as described in US Pat. No. 3,860,426, a water soluble metal salt (eg, zinc acetate) Examples include a process of providing a layer of hydrophilic cellulose (for example, carboxymethyl cellulose) and a process of applying a water-soluble polymer having a sulfo group described in JP-A-59-101651.

  Further, phosphates described in JP-A No. 62-019494, water-soluble epoxy compounds described in JP-A No. 62-033692, and JP-A No. 62-097892 Phosphate-modified starch, diamine compounds described in JP-A-63-056498, amino acid inorganic or organic acids described in JP-A-63-130391, JP-A-63-145092 Organic phosphonic acids containing carboxy group or hydroxy group, compounds having amino group and phosphonic acid group described in JP-A-63-165183, and JP-A-2-316290 Specific carboxylic acid derivatives, phosphate esters described in JP-A-3-215095, JP-A-3-261592 Compounds having one amino group and one oxygen acid group of phosphorus described in the publication, phosphoric esters described in JP-A-3-215095, and JP-A-5-246171 Aliphatic or aromatic phosphonic acids such as phenylphosphonic acid, compounds containing S atoms such as thiosalicylic acid described in JP-A-1-307745, and phosphorus described in JP-A-4-282737 The process which apply | coats the compound etc. which have the group of these oxygen acids is also mentioned.

  Further, a method of immersing in an aqueous solution of an alkali metal silicate such as sodium silicate and potassium silicate, and a hydrophilic treatment by applying a hydrophilic vinyl polymer or a hydrophilic compound are preferable.

Hydrophilization treatment with an aqueous solution of an alkali metal silicate such as sodium silicate and potassium silicate is described in US Pat. No. 2,714,066 and US Pat. No. 3,181,461. It can be performed according to methods and procedures.
Examples of the alkali metal silicate include sodium silicate, potassium silicate, and lithium silicate. The aqueous solution of alkali metal silicate may contain an appropriate amount of sodium hydroxide, potassium hydroxide, lithium hydroxide or the like.
The aqueous solution of alkali metal silicate may contain an alkaline earth metal salt or a Group 4 (Group IVA) metal salt. Examples of the alkaline earth metal salt include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate, and barium nitrate; sulfates; hydrochlorides; phosphates; acetates; oxalates; Examples of Group 4 (Group IVA) metal salts include titanium tetrachloride, titanium trichloride, potassium titanium fluoride, titanium oxalate, titanium sulfate, titanium tetraiodide, zirconium chloride, zirconium dioxide, zirconium oxychloride. And zirconium tetrachloride. These alkaline earth metal salts and Group 4 (Group IVA) metal salts are used alone or in combination of two or more.

The hydrophilic treatment by forming a hydrophilic layer can also be performed according to the conditions and procedures described in JP-A Nos. 59-101651 and 60-149491.
Examples of the hydrophilic vinyl polymer used in this method include polyvinyl sulfonic acid, sulfo group-containing vinyl polymerizable compounds such as p-styrene sulfonic acid having a sulfo group, and ordinary vinyl polymerization such as (meth) acrylic acid alkyl ester. And a copolymer with a functional compound. Examples of hydrophilic compounds that may be used in this method include, -NH ₂ group, compounds having at least one selected from the group consisting of -COOH group and sulfo group.

  Moreover, the method of apply | coating the liquid containing the hydrophilizing agent mentioned above to the surface of an anodized film, and making it dry is also mentioned.

  The method for the hydrophobization treatment is not particularly limited. For example, carboxymethyl cellulose; dextrin; gum arabic; phosphonic acids having an amino group such as 2-aminoethylphosphonic acid; phenylphosphonic acid optionally having a substituent Organic phosphonic acids such as naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, methylenediphosphonic acid, ethylenediphosphonic acid; phenylphosphoric acid, naphthylphosphoric acid, alkylphosphoric acid, glycerophosphoric acid which may have a substituent Organic phosphoric acid such as phenylphosphinic acid, naphthylphosphinic acid, alkylphosphinic acid, glycerophosphinic acid and the like which may have a substituent; amino acids such as glycine and β-alanine; Hydrochloric acid of amines having hydroxy groups such as hydrochloride Etc. and a method of forming a hydrophobic layer with. These may be used alone or in combination of two or more.

  Further, as the hydrophobic layer, a layer containing a polymer compound having a component having an acid group and a component having an onium group described in JP-A-2000-105462 is also preferably used.

  Moreover, the method of apply | coating the liquid containing the hydrophobizing agent mentioned above to the surface of an anodic oxide film, and making it dry is also mentioned.

  The coating method used for the hydrophilic treatment and the hydrophobic treatment is not particularly limited, and examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dipping coating, air knife coating, blade coating, and roll coating.

<Sealing treatment>
The structure of the present invention may be further sealed, and the micropores of the anodized film may be sealed with metal.
The metal is an element composed of a metal bond having free electrons, and is not particularly limited, but is preferably a metal in which plasmon resonance has been confirmed. Among these, gold, silver, copper, nickel, and platinum are known to easily cause plasmon resonance (Hyundai Kagaku, September 2003, p. 20 to 27 (non-patent document 9)), and are preferable. In particular, gold and silver are preferable because electrodeposition and colloidal particle preparation are easy.

The method for the sealing treatment is not particularly limited, and a conventionally known method can be used.
For example, an electrodeposition method; a method in which a dispersion of metal colloidal particles is applied to an aluminum member having an anodized film and dried is preferable. The metal is preferably a single particle or an aggregate.
As the electrodeposition method, a conventionally known method can be used. Specifically, for example, in the case of gold electrodeposition, an aluminum member is immersed in a dispersion at 30 ° C. containing 1 g / L HAuCl ₄ and 7 g / L H ₂ SO _4, and a constant voltage of 11 V ( (Adjusted with slidac), and a method of electrodeposition treatment for 5 to 6 minutes.
As the electrodeposition method, Hyundai Kagaku, January 1997, p. An example using copper, tin and nickel is described in detail in 51-54 (Non-Patent Document 10), and this method can also be used.

The dispersion used in the method using metal colloidal particles can be obtained by a conventionally known method. For example, it can be obtained by a method for producing fine particles by a low vacuum evaporation method or a method for producing a metal colloid that reduces an aqueous solution of a metal salt.
The metal colloidal particles preferably have an average particle size of 1 to 200 nm, more preferably 1 to 100 nm, and even more preferably 2 to 80 nm.
As the dispersion medium used in the dispersion, water is preferably used. In addition, solvents that can be mixed with water, for example, alcohols such as ethyl alcohol, n-propyl alcohol, i-propyl alcohol, 1-butyl alcohol, 2-butyl alcohol, t-butyl alcohol, methyl cellosolve, and butyl cellosolve A mixed solvent with water can also be used.

  In the method using metal colloidal particles, the coating method is not particularly limited, and examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

As the dispersion liquid used in the method using metal colloid particles, for example, a gold colloid particle dispersion liquid and a silver colloid particle dispersion liquid are preferably used.
As the dispersion of colloidal gold particles, for example, those described in JP-A-2001-89140 and JP-A-11-80647 can be used. Commercial products can also be used.
The dispersion of silver colloidal particles preferably contains silver and palladium alloy particles in that they are not affected by the acid eluted from the anodized film. In this case, the palladium content is preferably 5 to 30% by mass.

  After applying the dispersion, it is appropriately washed with a solvent such as water. As a result, only the particles filled in the micropores remain in the anodized film, and the particles not filled in the micropores are removed.

Adhesion amount of the metal after the sealing treatment is preferably 100 to 500 mg / m ^2.
The surface porosity after the sealing treatment is preferably 20% or less. The surface porosity after the sealing treatment is a ratio of the total area of the openings of the micropores not sealed with respect to the area of the aluminum surface. When the surface porosity is within the above range, stronger localized plasmon resonance is obtained.

  When the pore diameter is 50 nm or more, a method using metal colloidal particles is preferably used. Moreover, when a pore diameter is less than 50 nm, an electrodeposition method is used suitably. A method of combining both is also preferably used.

<Microstructure>
The microstructure of the present invention obtained as described above has a large average size of domains on the surface of the anodized film and a high degree of ordering. The microstructure of the present invention can be used for a sample stand for Raman spectroscopic analysis or the like using a structure in which metal is filled in the micropores of the anodized film in the field of biosensing, for example.
In particular, when the fine structure of the present invention is used for an application utilizing light transparency, when the region having a high regularity of the pore arrangement becomes wide, the sensing light reaches the detector without irregular reflection. High measurement accuracy. Further, when the micropores of the microstructure of the present invention are sealed with gold, a structure in which gold is regularly filled in the micropores can be obtained, which is useful as a sensing device.

The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these.
1. Fabrication of structure <aluminum plate>
The composition shown in Table 1 below, the remainder is made of Al and an inevitable impurity aluminum material, and after melt treatment and filtration, an ingot having a thickness of 500 mm and a width of 1200 mm is created by the DC casting method. did. After the surface was shaved with a chamfering machine with an average thickness of 10 mm, it was kept soaked at 550 ° C. for about 5 hours, and when the temperature dropped to 400 ° C., rolling with a thickness of 2.7 mm using a hot rolling mill A board was used. Furthermore, after heat treatment was performed at 500 ° C. using a continuous annealing machine, the thickness was 0.24 mm and the plate width was 1030 mm by cold rolling, and then the heat treatment with the temperature, treatment time, and number of treatments shown in Table 2 was performed. Thereafter, mirror finishing, pre-anodizing (depression formation), film removal, and main anodizing were sequentially performed to obtain each structure. In the table, “-” indicates that the corresponding processing is not performed. Table 1 shows the results obtained by measuring the Vickers hardness before heat treatment of the aluminum material before mirror finishing and the Vickers hardness after heat treatment at 300 ° C. for 2 hours.

Measurement of Vickers hardness In accordance with JISZ2251, a test piece (10 mm square flat plate) was prepared, and an indentation (indentation) was made on the surface of the aluminum material described above with a test load of 200 gf using a diamond square pyramid indenter with a facing angle of 136 °. The diagonal size of the indentation was measured based on the SEM observation photograph, and the Vickers hardness was calculated according to the formula defined in JIS.

  Hereinafter, each process will be described.

<Mirror finish processing>
By performing polishing using a polishing cloth, buffing and electrolytic polishing in this order, a mirror finish was applied. After buffing, it was washed with water.
Polishing using a polishing cloth uses a polishing machine (Struers Abramin, manufactured by Marumoto Kogyo Co., Ltd.) and a water-resistant polishing cloth (commercially available), and the number of the water-resistant polishing cloth is # 200, # 500, # 800, # 1000 and The change was made in the order of # 1500.
The buffing was performed using a slurry-like abrasive (FM No. 3 (average particle size 1 μm) and FM No. 4 (average particle size 0.3 μm), both manufactured by Fujimi Incorporated).
The electrolytic polishing was performed for 2 minutes using an electrolytic solution (temperature: 70 ° C.) having the following composition, using the anode as a substrate and the cathode as a carbon electrode at a constant current of 130 mA / cm ² . As a power source, GP0110-30R (manufactured by Takasago Seisakusho) was used.

<Electrolyte composition>
-660 mL of 85% by mass phosphoric acid (reagent manufactured by Wako Pure Chemical Industries, Ltd.)
・ Pure water 160mL
・ Sulfuric acid 150mL
・ Ethylene glycol 30mL

(3) Formation of a depression A depression that becomes the starting point of micropore formation in an anodic oxidation process described later was formed on the surface of a mirror-finished aluminum plate by the following method.

<Self-ordering method (pre-anodic oxidation)>
An aluminum plate is immersed in a 0.5 mol / L oxalic acid aqueous solution at 16 ° C., and subjected to a low voltage electrolytic treatment at a voltage of 40 V and a current density of 1.4 A / dm ² for 5 hours, thereby self-regulating anodizing treatment on the surface. Went. In the self-ordering anodizing treatment, NeoCool BD36 (manufactured by Yamato Scientific Co., Ltd.) is used as a cooling device, Pear Stirrer PS-100 (manufactured by EYELA) is used as a stirring and heating device, and GP0650-2R (manufactured by Takasago Seisakusho) is used as a power source. It was.

<Film removal treatment>
Next, the substrate on which the anodized film was formed was treated with a treatment liquid (liquid temperature 50 ° C.) consisting of 118 g of 85 mass% phosphoric acid aqueous solution (manufactured by Kanto Chemical Co.), 30 g of chromic anhydride (manufactured by Kanto Chemical Co., Ltd.) and 1500 g of pure water. For 12 hours to remove the anodized film.
The film thickness of the anodic oxide film after the film removal treatment was 0.1 μm or less.

(4) Main (main) anodizing treatment A
This anodizing treatment was performed on the substrate on which the depression was formed. This anodizing treatment was performed by immersing the substrate in an aqueous solution of 0.5 mol / L oxalic acid at 16 ° C., and subjecting the substrate to a low voltage electrolytic treatment at a voltage of 40 V and a current density of 1.4 A / dm ² for 2 minutes.

Domain Size Measurement Method FIG. 2 is a schematic diagram showing a domain size measurement method. Regularly arranged micropores are indicated by circles <o>. When this micropore array is connected by a straight line, there may be a case where a portion in which the array shift occurs as shown in FIGS. A portion where this deviation occurred was defined as a boundary, and a region surrounded by the boundary was defined as a domain. Considering the actual domain size and micropore size, 20-30 micropores prepared by ordered anodization with oxalic acid in each direction (L1, L2, L3 in the figure) measured in each domain are arranged. Will be. In order to measure the domain size, the surface of the main anodized aluminum surface is, for example, FE-SEM (Field Emission Type Scanning Electron Microscope), with an inclination angle of 0 ° and a magnification of 20,000 times. Shoot the micropore with. In the obtained image, the arrangement of pores is connected with straight lines in the L1, L2, and L3 directions intersecting every 60 ° as shown in FIG. 2, and the length that continues without disturbance is measured in each direction. The average was taken as the size of one domain. Images were taken for a field of view approximately equivalent to 1 × 10 ⁻³ mm ² , the sizes of at least 10 domains were measured, and the domain sizes were averaged to obtain an average domain size. At that time, the starting point of the measurement of the domain size shown in FIG. 2 was selected from several pores at almost the center of the domain, and the point where the domain size was maximized was selected.
The results are shown in Table 2.

  As is apparent from Table 2, the structure obtained by anodizing an aluminum plate having a Vickers hardness of 20 or less has an average domain size of 2 μm or more and is excellent in regularity.

2. Fabrication of the structure In addition, the same aluminum materials 1 to 3 were used, and the heat treatment shown in Table 2 was performed in the same manner except that the following anodizing treatment B (sulfuric acid electrolyte) was used. A structure was obtained in the same manner. The obtained structure was able to secure an average domain size of 2 μm or more as in the case of performing the present anodizing treatment A (oxalic acid electrolyte).
(4) 'This anodizing treatment B
The substrate was formed by immersing the substrate in a 0.3 mol / L sulfuric acid aqueous solution at 16 ° C. and subjecting the substrate to the depression formed at a voltage of 40 V and a current density of 1.4 A / dm ² for 2 minutes. .

3. Preparation of structure with and without hydrophilization treatment Among the heat treatment conditions in Table 2 above, three types of microstructures at 150, 250, 350 ° C x 2 hours were subjected to the same treatment and anodizing treatment as above 1. The products that were hydrophilized and those that did not were manufactured and evaluated as follows.
The results are shown in Table 3.
(5) Hydrophilization treatment The substrate was immersed in a 1% by mass sodium silicate aqueous solution at 35 ° C. for 10 seconds.

(6) Measurement of contact angle The fine structure was immersed in a cell filled with swazol (petroleum hydrocarbon mixture), and the contact angle of water droplets on the surface of the fine structure was measured in swathol. The measurement was performed using a Face contact angle meter CA-X manufactured by Kyowa Interface Science Co., Ltd. The measurement was performed 5 times to obtain an average value.
The results are shown in Table 3.
(7) Evaluation of gold filling property The following filling treatment (gold electrodeposition method) was performed on the fine structure.
Filling treatment (gold electrodeposition method): The structure is immersed in a dispersion at 30 ° C. containing 1 g / L of HAuCl ₄ and 7 g / L of H ₂ SO _4, and a constant voltage of 11 V (adjusted with slidac) Then, electrodeposition treatment was performed for 5 to 6 minutes. The uniformity of filling of the obtained gold electrodeposition structure was visually evaluated by observing an image taken using FE-SEM in the same manner as the domain size. It can be seen that when the Vickers hardness is lowered, the uniformity is improved and further improved by the hydrophilization treatment.
Excellent: Filled gold (Au) sizes (shape seen from above in FE-SEM photograph) are aligned.
Good: The size is uniform at least in the domain.
Yes: Sizes are not uniform within the domain, but there are no unfilled parts.
Impossible: Some parts are not filled.

  The results are shown in Table 3.

It is a schematic diagram showing the regularity and domains of micropores on the anodized surface. It is a figure of the pore of an anodized surface, and it is a schematic diagram which shows the measuring method of a domain size.

Explanation of symbols

5 micropore 10 cell 11 first domain 12 second domain

Claims (3)

A microstructure in which micropores obtained by anodizing an aluminum plate having a Vickers hardness Hv of 20 or less are regularly arranged ,
The aluminum plate is soaked in molten aluminum or aluminum alloy, then hot-rolled, and further cold-rolled, and then held at least once at 200 ° C. for 1 hour or longer. The fine structure which is an aluminum plate obtained by this .   The microstructure according to claim 1, wherein the regularity of the micropores is an average domain size of 2 μm or more. The aluminum or aluminum alloy melt is soaked, then hot-rolled, further cold-rolled, and held at least at least once at 200 ° C. for 1 hour or longer, with a Vickers hardness Hv of 20 or less. A method for producing a fine structure, in which an aluminum plate is obtained, and the aluminum plate is anodized to obtain a fine structure in which micropores are regularly arranged .

Images