JP2004107770A - Metallic plate coated with oxide film and production method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost, large area metallic plate which is coated with an oxide film having regularly arranged micropores and which is essential in putting an ultramicrofilter, high density magnetic recording media or the like into practical use. <P>SOLUTION: The metallic plate coated with the oxide film is obtained by forming the oxide film on the metallic plate comprising a substrate and a surface layer which consist of the same kind of valve metal. The valve metal used for the surface layer has a purity higher than that of the valve metal used for the substrate. The micropores of the oxide film are formed extending from the surface of the surface layer beyond the boundary between the surface layer and the substrate. The standard deviation of the intervals between the micropores is ≤20%. <P>COPYRIGHT: (C)2004,JPO

Description

【００５５】
【発明の効果】
本発明の酸化皮膜付き金属板は、規則的に配列した細孔を有し、しかも、比較的低価格な原材料を用いている。したがって、ウルトラミクロフィルター、高密度磁気記録メディア、光デバイス、磁気デバイス等の機能性材料に好適に用いられる。
また、本発明の酸化皮膜付き金属板の製造方法によれば、従来必須とされていた細孔形成の起点となる窪みの形成を行う必要がないので、規則的に配列した細孔を有する酸化皮膜付き金属板を大面積で、かつ、低価格で得ることができる。
【図面の簡単な説明】
【図１】本発明の酸化皮膜付き金属板およびその製造方法の説明図である。（Ａ）は陽極酸化処理前の金属板の模式的な断面図であり、（Ｂ）は陽極酸化処理後の金属板の模式的な断面図である。
【図２】本発明の酸化皮膜付き金属板の製造における陽極酸化処理に用いられる陽極酸化処理装置の概略図である。
【符号の説明】
２　基板
４　表面層
６　酸化皮膜
８　細孔
１０　金属板
２０　酸化皮膜付き金属板
４１０　陽極酸化処理装置
４１２　給電槽
４１４　電解処理槽
４１６　金属板
４１８、４２６　電解液
４２０　電極
４２２、４２８　ローラ
４２４　ニップローラ
４３０　電極
４３２　槽壁
４３４　直流電源[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a metal plate with an oxide film and a method for producing the same.
[0002]
[Prior art]
Conventionally, attempts have been made to regularly arrange the pores (micropores) of the anodized film and to apply them to functional materials such as optical devices and magnetic devices (for example, see Non-Patent Document 1). .
Japanese Patent Application Laid-Open No. H10-228667 describes a technique in which depressions regularly arranged on the surface of a substrate are formed in advance so as to be the starting point of pores in anodizing treatment. Japanese Patent Application Laid-Open No. H10-228561 describes a technique for forming depressions regularly arranged on the surface of a substrate in advance by a focused ion beam (FIB) method. Patent Document 3 describes a technique in which anodization or anodization is performed after a regular nanostructure pattern is formed using resist interference exposure. Patent Document 4 describes a technique in which an Al film is provided on a semiconductor, noble metal, manganese, cobalt, nickel, copper, and carbon substrate, and pores are formed in the Al film by anodizing treatment. Patent Document 5 describes a technique of providing an Al film on a substrate containing Ti, Zr, Nb, Ta, or Mo.
Each of these techniques is a technique in which depressions regularly arranged on the surface of the substrate are formed in advance and become the starting point of the pores in the anodizing process. As the method for forming the depression, the FIB method, the pressing method (a method in which a pressing mold having a fine depression is brought into close contact with the substrate and pressed to form the depression), the resist method (unevenness is formed on the surface of the substrate by the electron beam resist). Are known).
[0003]
[Non-Patent Document 1]
Hideki Masuda, “OPTRONICS”, 1998, No. 8, p. 211
[Patent Document 1]
JP-A-10-121292
[Patent Document 2]
JP 2001-105400 A
[Patent Document 3]
JP 2000-315785 A
[Patent Document 4]
JP 2000-31462 A
[Patent Document 5]
Japanese Patent Laid-Open No. 11-200090
[0004]
[Problems to be solved by the invention]
However, all of these techniques aim to obtain a substrate having a size of about 30 cm square at most, and are not suitable for mass production.
Therefore, the present invention provides a metal plate with an oxide film having regularly arranged pores having a large area and low cost, which is essential in the practical application of ultra-micro filters, high-density magnetic recording media, and the like, and a method for producing the same. The purpose is to do.
[0005]
[Means for Solving the Problems]
As a result of intensive studies for the purpose of mass production of metal plates with oxide films having regularly arranged pores, the present inventor has provided a surface layer with higher purity on the metal substrate, and then anodized. That the regularly arranged pores can be formed beyond the boundary between the surface layer and the substrate, and the method is easy and inexpensive for a large-area substrate. Found that can be done.
Specifically, the present inventor formed a surface layer having a higher purity on a substrate made of a valve metal and then anodized to form an anodized film and pores. Starting from the surface of the surface layer made of metal, regularly arranged pores can be obtained, and further anodic oxidation can continue the anode beyond the boundary between the surface layer and the substrate to the top of the substrate. Although an oxide film is formed, the regularly arranged pores grow downward as they are, so that the regular arrangement of the pores is maintained without being affected by impurities present in the substrate. It has been found that the price of raw materials can be reduced by making the surface layer sufficiently thin with respect to the substrate.
The present inventor completed the present invention based on the above findings.
[0006]
That is, the present invention provides the following (1) to (3).
[0007]
(1) It has a substrate and a surface layer, and the substrate and the surface layer are made of the same type of valve metal, and the valve metal used for the surface layer is more pure than the valve metal used for the substrate. A metal plate with an oxide film obtained by forming an oxide film on a high metal plate,
With pores in the oxide film formed from the surface layer surface beyond the boundary between the surface layer and the substrate, and with a standard deviation of the pore spacing of 20% or less Metal plate.
[0008]
(2) It has a substrate and a surface layer, the substrate and the surface layer are made of the same type of valve metal, and the valve metal used for the surface layer is more pure than the valve metal used for the substrate. A method for producing a metal plate with an oxide film, wherein the metal plate with an oxide film according to the above (1) is obtained by forming an oxide film on a high metal plate,
The manufacturing method of the metal plate with an oxide film which forms the said oxide film by anodizing with an indirect electric power feeding system.
[0009]
(3) The method for producing a metal plate with an oxide film according to (2), wherein after forming a depression on the surface of the metal plate, the oxide film is formed by performing an anodizing process by an indirect power feeding method.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a metal plate with an oxide film of the present invention and a manufacturing method thereof will be described in detail based on preferred embodiments shown in the accompanying drawings.
FIG. 1 shows an explanatory view of a metal plate with an oxide film of the present invention and a method for producing the same. FIG. 1A is a schematic cross-sectional view of the metal plate before the anodizing treatment, and FIG. 1B is a schematic cross-sectional view of the metal plate after the anodizing treatment.
The metal plate 10 used for manufacture of the metal plate with an oxide film of this invention has the board | substrate 2 and the surface layer 4, as FIG. 1 (A) shows.
The substrate 2 and the surface layer 4 are made of the same type of valve metal. Examples of the valve metal include Al, Ti, Ta, Hf, and Zr. The board | substrate 2 and the surface layer 4 should just consist of the same kind of valve metals, for example, the case where all are Al is mentioned.
[0011]
One feature of the present invention is that the valve metal used for the surface layer 4 is higher in purity than the valve metal used for the substrate 2. The reason will be described below.
An anodized film formed by anodizing treatment involves formation of pores called micropores. Although the pores originally have a property of regularly arranging, it is actually difficult to obtain a regular arrangement. One of the causes is the presence of impurities. That is, if impurities exist in the valve metal, a regular arrangement of pores cannot be obtained.
Therefore, for example, by using a high-purity valve metal having a purity of 99.95% by mass or more as the substrate, the regularity of the arrangement of the pores can be improved, but the high-purity valve metal is expensive. There's a problem.
In contrast, in the present invention, the valve metal used for the surface layer 4 is made to be higher in purity than the valve metal used for the substrate 2, so that a high-purity valve metal is used for the surface layer. While a regular arrangement of the holes can be obtained, a low-priced valve metal of the same type as the surface layer can be used for the substrate to reduce the cost of the raw material.
[0012]
The purity of the valve metal used for the surface layer 4 is preferably 99.0% by mass or more, and more preferably 99.95% by mass or more. Within the above range, the regularity of the arrangement of the pores becomes high.
On the other hand, the purity of the valve metal used for the substrate 2 is not particularly limited as long as it is lower than the purity of the valve metal used for the surface layer 4. For example, a commercial metal substrate having a purity of 99% by mass or less that is mass-produced at a relatively low price can be suitably used as the substrate 2.
[0013]
As the substrate 2, a conventionally known plate made of a valve metal can be used, but a plate having a regular reflectance of 65% or more on the surface on which the surface layer 4 is provided is preferably used.
One of the reasons why it is difficult to obtain a regular arrangement of pores is the presence of irregularities on the surface of the substrate to be anodized. That is, if there are irregularities on the surface of the substrate, the arrangement of the pores tends to be irregular.
Therefore, in the present invention, the substrate 2 is a plate with less surface irregularities, specifically, a plate having a regular reflectance of 65% or more, preferably 70% or more (difference in length and width in the crystal structure of the plate). When there is anisotropy, the use of a plate having a regular reflectance of 65% or more and preferably 70% or more on the surface in the vertical direction and the horizontal direction improves the regularity of the arrangement of the pores. It is preferable.
[0014]
A method for obtaining the metal plate 10 by providing the surface layer 4 on the substrate 2 is not particularly limited, but any one of a vapor deposition method, a sputtering method, and an electrodeposition method is preferably used.
According to these methods, since the surface layer 4 having no crystal structure anisotropy can be obtained without being affected by the crystal structure anisotropy of the substrate 2, the regularity of the pore arrangement is excellent. It will be. In addition, according to these methods, when a plate having less surface irregularities is used as the substrate 2, the surface shape of the substrate 2 can be reflected, that is, the surface layer 4 having less surface irregularities is obtained. Therefore, the regularity of the arrangement of the pores is excellent. Furthermore, according to these methods, the surface layer 4 that is extremely thin as compared with the substrate 2 can be formed, and thus the surface layer 4 can be obtained at a low cost. Conventionally known methods and conditions can be used for the vapor deposition method, sputtering method and electrodeposition method.
[0015]
The thickness of the surface layer 4 is not particularly limited, but it is preferably 0.05 μm or more, more preferably 0.1 μm or more in terms of regularity improvement effect, and the cost of raw materials and production is also reduced. In this respect, it is preferably 1 μm or less, and more preferably 0.5 μm or less.
[0016]
In the present invention, the metal plate 10 obtained as described above is subjected to anodizing treatment. However, a depression can be formed on the surface of the metal plate 10 before the anodizing treatment. Thereby, the regularity of the arrangement | sequence of the pore in an anodizing process can be improved.
The method for forming the depression on the surface of the metal plate 10 is not particularly limited, and a conventionally known method such as the above-described FIB method, pressing method, or resist method can be used.
[0017]
In the present invention, the metal plate 10 obtained as described above is anodized.
In the initial stage of the anodizing treatment, the surface layer 4 existing on the surface of the metal plate 10 is oxidized to form an oxide film. However, since the surface layer 4 is made of a high-purity valve metal, pores formed in the oxide film Has a regular array.
When the anodizing treatment is continued, the oxidation proceeds from the surface of the metal plate 10 to a deep portion. That is, as shown in FIG. 1 (B), the oxide film 6 goes to the upper part of the substrate 2 beyond the portion that was the surface layer 4 (portion above the dotted line in the figure). At this time, as shown in FIG. 1B, the pores 8 also grow beyond the substrate 2. However, since the pores 8 are regularly arranged in the surface layer 4, impurities present in the substrate 2 are present. The regular arrangement of the pores 8 is maintained without being affected by the above.
In this way, the metal plate 20 with an oxide film of the present invention in which the pores 8 in the oxide film 6 are formed from the surface of the surface layer 4 beyond the boundary between the surface layer 4 and the substrate 2 is obtained.
[0018]
In the method for producing a metal plate with an oxide film of the present invention, anodization is performed by an indirect power feeding method. Hereinafter, the anodizing treatment will be described in detail.
[0019]
As an anodizing method, an indirect power feeding method and a direct power feeding method are conventionally known. The indirect power supply method is a method in which a metal plate is passed through an electrolyte solution in which an electrode (anode in the case of direct current) exists, and then in an electrolyte solution in which an electrode (a cathode in the case of direct current) is present. This is a method of passing. The direct power feeding method is a method in which a metal plate is brought into contact with an electrode (in the case of direct current, an anode) and then passed through an electrolyte solution in which an electrode (a cathode in the case of direct current) is present. is there.
Compared with the direct power supply method, the indirect power supply method has a more uniform voltage distribution of the metal plate, so that the regularity of the pores of the generated oxide film is superior in the planar direction and the depth direction. Further, in the direct power feeding method, a spark is generated at a portion where the metal plate and the electrode are in contact with each other, and the oxide film is not normally formed at that portion, resulting in unevenness. For these reasons, an indirect power feeding method is used in the present invention.
[0020]
As the indirect power feeding type anodizing apparatus used in the present invention, a conventionally known apparatus can be used.
Among these, the apparatus shown in FIG. 2 is preferably used. FIG. 2 is a schematic view showing an example of an apparatus for anodizing the surface of a metal plate such as an aluminum plate. In the anodizing apparatus 410, the metal plate 416 is conveyed as shown by the arrows in FIG. In the power supply tank 412 in which the electrolytic solution 418 is stored, the metal plate 416 is charged to (+) by the (power supply) electrode 420. Then, the metal plate 416 is conveyed upward by the roller 422 in the power supply tank 412, changed in direction downward by the nip roller 424, and then conveyed toward the electrolytic treatment tank 414 in which the electrolytic solution 426 is stored. The direction is changed horizontally. Next, the metal plate 416 is charged to (−) by the (electrolysis) electrode 430 to form an anodic oxide film on the surface thereof, and the metal plate 416 exiting the electrolytic treatment tank 414 is conveyed to a subsequent process. . In the anodizing treatment apparatus 410, the roller 422, the nip roller 424, and the roller 428 constitute a direction changing means, and the metal plate 416 is disposed between the power supply tank 412 and the electrolytic treatment tank 414 in the section between the rollers 422, 424 and By 428, it is conveyed into a mountain shape and an inverted U shape. The (power supply) electrode 420 and the (electrolysis) electrode 430 are connected to a DC power supply 434.
[0021]
The feature of the anodizing apparatus 410 in FIG. 2 is that the feeding tank 412 and the electrolytic treatment tank 414 are partitioned by a single tank wall 432, and the metal plate 416 is conveyed in a mountain shape and an inverted U shape between the tanks. It is in. Thereby, the length of the metal plate 416 in the inter-tank part can be minimized. Therefore, the overall length of the anodizing apparatus 410 can be shortened, so that the equipment cost can be reduced. In addition, by conveying the metal plate 416 in a mountain shape and an inverted U shape, it is not necessary to form an opening for allowing the metal plate 416 to pass through the tank walls of the tanks 412 and 414. Therefore, since the liquid feeding amount required to maintain the liquid level height in each tank 412 and 414 at a required level can be suppressed, the operating cost can be reduced.
[0022]
Using such an anodizing apparatus, for example, in a solution having a sulfuric acid concentration of 50 to 300 g / L and an aluminum concentration of 5% by mass or less, a metal plate can be energized to form an anodized film. . 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.
[0023]
The conditions for anodizing treatment vary depending on the electrolyte used, and thus cannot be determined unconditionally. In general, however, the electrolyte concentration is 1 to 80% by mass, the solution temperature is 5 to 70 ° C., and the current density is 0.5. ~ 60A / dm ² It is appropriate that the voltage is 1 to 100 V and the electrolysis time is 15 seconds to 50 minutes, and the amount of the oxide film is adjusted.
[0024]
As anodizing treatment, a DC electrolysis method using a DC power source and an AC electrolysis method using an AC power source are known. In the present invention, a direct current electrolysis method is usually used. However, in the case where functional particles are embedded in the pores 8 as described later, an alternating current electrolysis method is also preferably used.
[0025]
The amount of the desired oxide film varies depending on the application, but is 1.0 g / m in terms of productivity and ease of handling. ² (Thickness of about 0.3 μm) or more is preferable, 4.0 g / m ² More preferably, it is 5.0 g / m. ² The above is more preferable.
[0026]
The amount of oxide film obtained by the anodizing treatment is proportional to the amount of electricity applied to the metal plate. Regarding the amount of electricity, the relationship of the following formula (1) is established.
[0027]
Electricity (C / m ² ) = Current (A / m ² ) X Processing time (seconds) (1)
[0028]
Therefore, in the case of the constant current method, the anodic oxidation treatment is performed by changing the treatment time, the amount of the oxide film is measured according to the provisions of JIS H8680-7 (film weight method), and a calibration curve is created. The processing time corresponding to the desired amount of oxide film can be determined.
However, in the method prescribed in JIS H8680-7 (film weight method), since a powerful drug such as an aqueous chromic acid solution is boiled and used, it is unsafe and time-consuming. Therefore, a fluorescent X-ray analysis method can be simply substituted. That is, a part of the calibration curve sample was measured for the amount of oxide film according to JIS H8680-7 (film weight method), and the other part was measured by fluorescent X-ray analysis (Lh Lα ray Compton scattered radiation). A calibration curve can be created by actually measuring the scattering intensity.
[0029]
By subjecting the metal plate 10 to anodic oxidation as described above, fine pores 8 called micropores are formed on the surface.
The pore diameter of the pores 8 can be appropriately changed depending on the application. For example, when using the metal plate 20 with an oxide film of the present invention for an ultra micro filter or the like, the thickness is preferably 40 to 300 nm. As will be described later, when nanomagnetic particles are embedded and used as a medium for high-density magnetic recording, the thickness is preferably 20 to 150 nm.
[0030]
It is known that the pore diameter of the pore 8 is proportional to the electrolysis voltage. Therefore, when the pore diameter is increased, the electrolysis voltage may be increased, and when the pore diameter is decreased, the electrolysis voltage may be decreased. Further, by gradually increasing the electrolysis voltage during the anodizing treatment, pores that expand toward the bottom portion are generated.
[0031]
Further, the pore diameter of the pores 8 also depends on the type of the electrolytic solution. This is because the electrolytic voltage and the pH of the electrolytic solution are different when the type of the electrolytic solution is different. Generally, sulfuric acid, oxalic acid, and phosphoric acid are used in order from the smallest pore size. Therefore, the pore 8 having a desired pore diameter can be obtained by using an electrolytic solution in which two or more acids are mixed. Further, the pore diameter can be adjusted in the depth direction by changing the electrolytic solution twice and performing the treatment twice, or by connecting two or more treatment apparatuses and performing two or more steps of treatment. For example, a method of increasing the electrolysis voltage using a phosphoric acid electrolyte, a method using a sulfuric acid electrolyte in the first stage, a method using a phosphoric acid electrolyte in the second stage, etc. Holes can be generated.
[0032]
Also, if the temperature of the electrolyte is increased, the pH of the electrolyte is lowered from the neutral range to the acidic side, or increased to the alkaline side, the anodized film dissolves, so the pore diameter of the pores It is also known that tends to increase.
[0033]
Moreover, the pore diameter of the pore 8 can be enlarged by performing the pore enlargement treatment after the anodizing treatment.
The pore enlargement process is a process in which the oxide film 6 is partially dissolved and the pore diameter 8 is enlarged by immersing the metal plate 20 with an oxide film obtained by anodizing treatment in an acid aqueous solution or an alkali aqueous solution. is there. Specifically, the dissolution amount of the oxide film 6 is preferably 0.01 to 20 g / m. ² , More preferably 0.1 to 5 g / m ² , Particularly preferably 0.2 to 4 g / m ² It is performed in the range.
[0034]
When an acid aqueous solution is used for the pore enlargement 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 10 to 1000 g / L, and more preferably 20 to 500 g / L. The temperature of the acid aqueous solution is preferably 10 to 90 ° C, and more preferably 30 to 70 ° C. The immersion time in the acid aqueous solution is preferably 1 to 300 seconds, and more preferably 2 to 100 seconds.
On the other hand, when an alkaline aqueous solution is used for the pore enlargement 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 pH of the alkaline aqueous solution is preferably 10 to 13, and more preferably 11.5 to 13.0. The temperature of the aqueous alkali solution is preferably 10 to 90 ° C, and more preferably 30 to 50 ° C. The immersion time in the alkaline aqueous solution is preferably 1 to 500 seconds, and more preferably 2 to 100 seconds.
[0035]
In the metal plate 20 with an oxide film of the present invention, functional particles such as nanomagnetic particles may be embedded in the pores 8. By embedding the functional particles, various electromagnetic characteristics can be provided.
As the method of embedding the functional particles, for example, after anodizing treatment, preferably after pore enlargement treatment, a solution in which the functional particles are dispersed in a solvent is dipped, sprayed, sprayed, applied, etc. A method of exposing to the surface of the attached metal plate 20 and then drying to remove the solvent may be mentioned.
Moreover, the method of depositing the functional particles in the pores 8 by applying the above-described anodizing treatment by an alternating current electrolysis method using an electrolytic solution in which the functional particles are dissolved is also included.
[0036]
The metal plate 20 with an oxide film of the present invention thus obtained has a regular arrangement of the pores 8. Specifically, in the metal plate 20 with an oxide film of the present invention, the standard deviation of the interval between the pores 8 is 20% or less, preferably 10% or less.
Since the metal plate 20 with an oxide film of the present invention has a regular arrangement of the pores 8 and a standard deviation of the interval between the pores 8 is 20% or less, the ultra-micro filter, the high-density magnetic recording medium, and the optical device. It is suitably used for functional materials such as magnetic devices.
[0037]
For observation of the oxide film 6 on the metal plate 20 with an oxide film of the present invention, a high resolution transmission electron microscope (high resolution TEM), an ultra high resolution scanning electron microscope (ultra high resolution SEM), or the like is used. be able to. When using a high-resolution TEM, it is necessary to cut out and observe an ultrathin section using an apparatus called a microtome, which is very time-consuming, and therefore an ultrahigh-resolution SEM is usually used. By observing the oxide film in this way, the thickness, pore diameter, pore spacing, etc. of the oxide film can be measured.
[0038]
In the production of the metal plate with an oxide film of the present invention, for example, equipment for continuously casting a metal plate, equipment for providing a surface layer, anodizing equipment, equipment for expanding pores, equipment for embedding functional particles, and reverse electrolysis peeling. By providing the facilities in this order, the manufacturing cost can be extremely reduced by continuously manufacturing the metal plate with an oxide film.
Generally, equipment for continuously casting metal plates and equipment for providing a surface layer are dry equipment that does not use water, and equipment after anodizing equipment is wet equipment that uses water. In the case of continuous production, the discontinuity between the dry equipment and the wet equipment may improve the production efficiency, but it is preferably continuous.
[0039]
Conventionally known equipment can be used as equipment for continuously casting a metal plate, equipment for providing a surface layer, equipment for anodizing treatment, equipment for expanding pores, equipment for embedding functional particles, and reverse electrolysis peeling equipment.
Here, the reverse electrolysis peeling equipment is basically the same equipment as the anodizing equipment, but is equipment for transferring the peeled oxide film onto paper or the like after the electrolysis is reversed.
Such equipment can be produced by diverting part of equipment for producing a conventionally known planographic printing plate precursor.
[0040]
【Example】
EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.
1. Manufacture of metal plate with oxide film
In the combinations shown in Table 1, the following substrates were subjected to surface layer formation, depression formation and anodizing treatment. Each process is as follows.
[0041]
(1) Substrate
The following aluminum plates were used as substrates. The regular reflectance of each substrate was measured according to “60 degree specular gloss” defined in Method 3 of JIS Z8741-1997. Specifically, by using a variable angle gloss meter (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 exceeds 70%. In some cases, the incident / reflection angle was 20 degrees. The purity of each substrate was measured by a calibration curve method using an emission analyzer (PDA-5500, manufactured by Shimadzu Corporation).
[0042]
(1) XL untreated material
Made by Sumitomo Light Metal Industries, Inc. 85% specular reflectance in the vertical direction (standard deviation 5%), 83% specular reflectance in the horizontal direction (standard deviation 5%), purity 99.3% by mass (standard deviation 0.1% by mass) )
(2) JIS A1050 material
Manufactured by Sumitomo Light Metal Industry Co., Ltd., vertical regular reflectance 40% (standard deviation 10%), horizontal regular reflectance 15% (standard deviation 10%), purity 99.5 mass% (standard deviation 0.1 mass%) )
[0043]
(2) Formation of surface layer
A surface layer was formed on the substrate by vacuum deposition or sputtering under the following film forming conditions.
(1) Film forming condition A
Vacuum deposition method, ultimate pressure 5 × 10 ^-3 Pa, vapor deposition current 40A, substrate unheated, vapor deposition material 99.999 mass% Al wire
(2) Film forming condition B
Vacuum deposition method, ultimate pressure 5 × 10 ^-3 Pa, vapor deposition current 40A, substrate unheated, vapor deposition material 99.99 mass% Al wire
(3) Film forming condition C
Vacuum deposition method, ultimate pressure 5 × 10 ^-3 Pa, vapor deposition current 40A, substrate unheated, vapor deposition material 99.95 mass% Al wire
(4) Film formation condition D
Sputtering method, ultimate pressure 5 × 10 ^-4 Pa, sputtering pressure 6.7 × 10 ^-1 Pa, argon flow rate 20 sccm, substrate unheated, substrate cooled, no bias, sputtering power supply RC, sputtering power RF 400 W, sputtering material 99.95 mass% Al
[0044]
The thickness of the surface layer is determined by masking the PET substrate, performing vacuum deposition under film forming conditions A to C, and sputtering under film forming condition D while changing the time, and using an atomic force microscope (Atomic Force Microscope). : AFM) was adjusted to a desired value by adjusting the time using a correlation calibration curve between the time and the film thickness obtained by measuring each film thickness by AFM). The results are shown in Table 1.
[0045]
In addition, the purity of the surface layer was determined using a scanning X-ray photoelectron spectrometer (Quantum 2000, manufactured by ULVAC-PHI) to perform a full quantitative analysis while digging in the depth direction with an ion gun for etching. The content of was quantified by a calibration curve method. The results are shown below.
[0046]
(1) Film forming condition A: 99.995% by mass (standard deviation 0.005% by mass)
(2) Film forming condition B: 99.95% by mass (standard deviation 0.05% by mass)
(3) Film forming condition C: 99.9% by mass (standard deviation 0.1% by mass)
(4) Film forming condition D: 99.9% by mass (standard deviation 0.1% by mass)
[0047]
(3) Formation of depression
A focused ion beam processing apparatus was used to irradiate the surface layer with a focused ion beam to form a recess that was the starting point for pore formation in anodizing. Ga was used as the ion species, the acceleration voltage was 30 kV, the ion beam diameter was about 30 nm, and the ion current was about 3 pA.
At this time, using the secondary electron observation function of the focused ion beam processing apparatus, the depressions were positioned, and irradiation was repeated so that a honeycomb pattern (closest packed structure) with an interval of about 100 nm was obtained. The stay time of the focused ion beam in each depression was about 10 msec.
[0048]
(4) Anodizing treatment
Anodizing treatment was performed with the type of electrolytic solution shown in Table 1, the concentration of the electrolytic solution, the temperature of the electrolytic solution, the current density, the voltage, and the power feeding method to form an oxide film with the thickness shown in Table 1, and oxidation A metal plate with a film was obtained. Here, the thickness of the oxide film was adjusted by changing the treatment time.
It is known that the current density varies depending on the formation of the anodized film when the constant voltage electrolytic treatment is performed, but generally depends on the liquid resistance value of the electrolytic solution. That is, the current density varies greatly depending on the temperature, concentration, stirring conditions, electrode arrangement, and the like of the electrolytic solution. In general, the liquid resistance value is sulfuric acid, oxalic acid, and phosphoric acid in order from the lowest. In Table 1, the values after the current density was stabilized are shown.
[0049]
In the case of the indirect power feeding method, an anodizing apparatus using direct current electrolysis having the structure shown in FIG. 2 was used. The same electrolytic solution was supplied to the first and second electrolysis parts.
In the case of the direct power supply method, in the anodizing apparatus using direct current electrolysis having the structure shown in FIG. 2, the nip roller 424 is removed and replaced with a pure copper metal roll serving as a power supply roll (anode), and the circuit from the anode of the DC power supply 434 is replaced. The electrode 420 is removed from the electrode 420 and connected to the pure copper metal roll to conduct, while the electrode 420 and the electrode 430 are connected by a bus bar to conduct and function as a pair of cathodes so that a current flows in the electrolyte. Used. The same electrolytic solution was supplied to the first and second electrolysis parts.
[0050]
2. Properties of oxide film
About the metal plate with an oxide film obtained above, the property of the oxide film was measured as follows. The results are shown in Table 1.
(1) Thickness
A fracture surface created by bending a metal plate with an oxide film was observed with an ultra-high resolution scanning electron microscope (S-900, manufactured by Hitachi, Ltd.) at a magnification of 50,000 times. Fracture surfaces at 50 locations were randomly extracted, and the oxide film thickness was measured and averaged. The standard deviation was 0.10 or less.
[0051]
(2) Average pore diameter
Using a super high resolution scanning electron microscope (S-900, manufactured by Hitachi, Ltd.), the surface of the metal plate with an oxide film is subjected to a relatively low acceleration voltage of 12 V and without performing a vapor deposition process for imparting conductivity. And observed at a magnification of 150,000 times. Fifty pores (micropores) were randomly extracted to obtain an average value, which was defined as the average pore diameter of the oxide film. The standard deviation was 0.10 or less.
[0052]
(3) Average pore spacing and standard deviation of pore spacing
The surface of the metal plate with an oxide film was observed in the same manner as described above. The distance between the centers of the pores was measured at 100 consecutive points, and the average value and standard deviation were obtained.
[0053]
As is apparent from Table 1, the metal plate with an oxide film of the present invention (Examples 1 to 11) obtained by the method for producing a metal plate with an oxide film of the present invention has a depression in the substrate which is a conventional method. The pores of the oxide film are arranged very regularly as compared with the one formed and anodized (Comparative Example 2). In particular, when the anodic oxidation treatment is performed after forming the depressions in the surface layer (Example 4), they are particularly regularly arranged.
On the other hand, when the surface layer is not provided on the surface of the substrate (Comparative Examples 1 to 3), the pores of the oxide film are not regularly arranged. Also, when the anodization is performed by the direct power supply method (Comparative Example 4), the pores of the oxide film are not regularly arranged.
[0054]
[Table 1]

[0055]
【The invention's effect】
The metal plate with an oxide film of the present invention has regularly arranged pores and uses a relatively inexpensive raw material. Therefore, it is suitably used for functional materials such as ultra-micro filters, high-density magnetic recording media, optical devices, and magnetic devices.
In addition, according to the method for producing a metal plate with an oxide film of the present invention, it is not necessary to form a depression that is a starting point for pore formation, which has been essential in the past, and therefore, an oxide having regularly arranged pores. A coated metal plate can be obtained with a large area and at a low price.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an explanatory view of a metal plate with an oxide film and a method for producing the same according to the present invention. (A) is a schematic cross-sectional view of the metal plate before the anodizing treatment, and (B) is a schematic cross-sectional view of the metal plate after the anodizing treatment.
FIG. 2 is a schematic view of an anodizing apparatus used for anodizing in the production of a metal plate with an oxide film according to the present invention.
[Explanation of symbols]
2 Substrate
4 Surface layer
6 Oxide film
8 pores
10 Metal plate
20 Metal plate with oxide film
410 Anodizing equipment
412 Feeding tank
414 Electrolytic treatment tank
416 metal plate
418, 426 electrolyte
420 electrodes
422, 428 Roller
424 Nip roller
430 electrode
432 tank wall
434 DC power supply

Claims (3)

A metal plate having a substrate and a surface layer, wherein the substrate and the surface layer are made of the same type of valve metal, and the valve metal used for the surface layer is higher in purity than the valve metal used for the substrate. In addition, a metal plate with an oxide film obtained by forming an oxide film,
With pores in the oxide film formed from the surface layer surface beyond the boundary between the surface layer and the substrate, and with a standard deviation of the pore spacing of 20% or less Metal plate. A metal plate having a substrate and a surface layer, wherein the substrate and the surface layer are made of the same type of valve metal, and the valve metal used for the surface layer is higher in purity than the valve metal used for the substrate. A method for producing a metal plate with an oxide film, wherein the metal plate with an oxide film according to claim 1 is obtained by forming an oxide film.
The manufacturing method of the metal plate with an oxide film which forms the said oxide film by anodizing with an indirect electric power feeding system. The method for producing a metal plate with an oxide film according to claim 2, wherein after forming a depression on the surface of the metal plate, the oxide film is formed by performing an anodizing process by an indirect power feeding method.

Images