JP6992314B2 - Anodic oxide film and its manufacturing method - Google Patents

Description

The present invention relates to an anodic oxide film and a method for producing the same, and more particularly to a colored anodic oxide film applied to the surface of an aluminum or aluminum alloy member and a method for producing the same.

Conventionally, the surface of an aluminum or aluminum alloy member is anodized to form an anodic oxide film, which is a porous film, and then immersed in an aqueous solution containing a colorant to form an anodic oxide film on the surface or in pores. A colorant is attached to color the anodized film.

After coloring, in order to prevent color loss, a pore-sealing treatment is generally performed in which the pores are filled with a compound using a solution in an acidic pH range. A general sealing treatment method is a method of immersing an aluminum part in an aqueous solution of nickel acetate at 80 to 100 ° C. for 10 minutes or more. There was a problem from the point of view.

On the other hand, in recent years, a technique has been developed that can perform a pore-sealing treatment at a low temperature and in a short time by using an alkaline aqueous solution containing lithium ions as described in Patent Document 1.

Further, in Patent Document 2, a method of performing a sealing treatment at a temperature slightly lower than the temperature of a general sealing treatment using an aqueous solution of nickel acetate has been found. This method uses an aqueous solution containing a divalent manganese salt and at least one of the sulfonate-type anionic surfactant and the sulfate ester-type anionic surfactant to seal the pores. It is a method of processing.

In addition to this, as Patent Document 3, a method for sealing without using a harmful compound such as a nickel compound is known. In this method, an anodic oxide film colored with a colorant is immersed in an aqueous solution of a water-soluble cationic polymer, and then the sealing treatment is performed with a sealing treatment liquid containing a magnesium salt or a calcium salt. In this method, the cationic polymer has the effect of fixing the colorant in the film, so that decolorization due to the sealing can be suppressed.

Japanese Unexamined Patent Publication No. 2010-77532 Japanese Unexamined Patent Publication No. 2015-4083 Japanese Unexamined Patent Publication No. 2010-248545

As a result of repeated studies by the present inventors, when the pore-sealing treatment using the alkaline aqueous solution described in Patent Document 1 is applied to the colored anodic oxide film, the colorant is removed from the pores at the time of sealing, and the color is decolorized. Turned out to be a problem.

Further, in the method described in Patent Document 2, the sealing liquid temperature is 65 to 95 ° C., which is only slightly lower than the temperature of general sealing treatment, energy consumption is still large, and manganese to be used is used. Since the compound is harmful, there is a problem that it is not preferable in the working environment.

In the method described in Patent Document 3, the polymer molecular weight of the aqueous polymer solution changes due to polycondensation, and there remains a concern for stable production. Further, in the sealing treatment by this method, it is necessary to heat the treatment liquid to 80 ° C. or higher, which poses a problem from the viewpoint of energy consumption.

In this way, when the anodic oxide film is colored and the pores are sealed, decolorization does not occur at a low temperature and in a short time, energy consumption is suppressed, the environment is taken into consideration, and stable mass production can be performed. There is a demand for a method for producing an anodic oxide film.

Therefore, an object of the present invention is to provide a colorful and environment-friendly anodic oxide film and a method for producing the same, which can be sealed at a low temperature and in a short time and can suppress decolorization.

The present invention is one aspect of the present invention, which is a method for producing an anodic oxide film, which comprises an anodic oxidation treatment step of forming an anodic oxide film having pores, a coloring step of coloring the pores of the anodic oxide film, and the coloring. The pore pretreatment step of contacting the pores of the anodic oxide film with an aqueous solution containing a surfactant that becomes anions when dissociated in water, and the pores of the anodic oxide film contacted with the surfactant are alkaline aqueous solutions. It includes a sealing treatment step of sealing with.

The surfactant is preferably an anionic surfactant. Further, the surfactant is more preferably any one of a carboxylate type, a sulfonate type, and a sulfate ester type anionic surfactant, or a combination thereof. In particular, the above-mentioned surfactant is more preferably a carboxylate type.

The alkaline aqueous solution preferably contains lithium ions.

The concentration of the aqueous solution containing the surfactant may be 1 g / L or more.

The temperature of the aqueous solution containing the surfactant may be 10 to 70 ° C.

The present invention is another aspect of the colored anodic oxide film, wherein the pores of the anodic oxide film are sealed with LiH (AlO ₂ ) _{2.5H 2O} and / or AlO (OH). The color difference ΔE calculated from the SCI (Special Component Invention) of the colored anodized film is 8.9 or less.

According to the present invention, after coloring the anodic oxide film having pores, the pores of the anodic oxide film are subjected to pre-sealing treatment in which the pores of the anodic oxide film are brought into contact with an aqueous solution containing a surfactant that becomes an anion when dissociated in water. Then, surprisingly, the sealing treatment can be performed at a low temperature for a short time by performing a sealing treatment for sealing the pores of the anodic oxide film in contact with the surfactant with an alkaline aqueous solution. Is used as the pore-sealing treatment liquid, the decolorization of the colorant from the pores of the anodic oxide film can be suppressed during the pore-sealing treatment, and a good appearance can be obtained.

6 is a photograph of an SEM showing the surface of the anodic oxide film used as a control in the examples. It is a photograph of SEM showing the cross section of the anodic oxide film used as a control in an example. It is a graph which shows the change of the color difference when the concentration of the surfactant in the sealing pretreatment liquid is changed in Example 1. FIG. It is a photograph of the test piece before and after the sealing treatment in Example 1. It is a graph which shows the change of the color difference when the immersion time in the sealing pretreatment liquid is changed in Example 2. FIG. It is a photograph of the test piece before and after the sealing treatment in Example 2. It is a graph which shows the change of the color difference when the temperature of the sealing pretreatment liquid is changed in Example 3. FIG.

Hereinafter, an embodiment of the anodic oxide film and the method for producing the anodic oxide film according to the present invention will be described. The manufacturing method of the present embodiment is a step of anodizing to form an anodized film having pores, a coloring step of coloring the pores of the anodized film, and when the pores of the colored anodized film are dissociated in water. It includes a sealing pretreatment step of contacting the anodic oxide film with an aqueous solution containing an anodized surfactant and a sealing treatment step of sealing the pores of the anodized film in contact with the anodized aqueous solution with an alkaline aqueous solution. The object to be treated on which the anodic oxide film is formed and each of the above steps will be described in detail.

1. 1. The object to be treated The object to be treated on which the anodic oxide film of the present invention is formed is mainly aluminum or an aluminum alloy member, but the same effect can be expected even if other materials are used. Examples of the aluminum alloy member include wrought materials, cast materials, and die-cast materials, but the present invention is not particularly limited, and alloy components such as silicon and copper are not particularly limited. Further, for example, when anodizing with an ADC12 material having a high silicon component ratio, a blackish-colored film is formed, and depending on the alloy components contained, a colored film is formed during the anodizing treatment. The material may be selected in consideration of the color to be produced.

2. 2. Anodizing process Next, the conditions for anodizing will be described. Regarding the anodizing treatment of the object to be treated, the object to be treated is placed on the anode and titanium, a stainless steel plate or the like is placed on the cathode in the anodizing solution, and the electrolytic treatment is performed. As a result, an anodic oxide film containing aluminum oxide as a main component is formed on the surface of the object to be treated. The anodic oxidation treatment liquid may be an acidic aqueous solution such as sulfuric acid, oxalic acid, phosphoric acid or chromic acid, or an alkaline aqueous solution such as sodium hydroxide, sodium phosphate or sodium fluoride, and is not particularly limited.

The film thickness of the anodic oxide film is usually preferably 3 to 40 μm. More preferably, it is 5 μm or more, and 20 μm or less. When the film thickness is 3 μm or more, a porous film sufficient for the colorant to adhere can be formed, and the amount of the colorant to be attached can be reduced to obtain a light color. .. On the contrary, when the film thickness is 40 μm or less, it is possible to adjust the coloration so that a large amount of the colorant adheres to the pores of the film so that the color is darkened. Can be prepared.

Examples of the electrolysis treatment include DC electrolysis, AC electrolysis, AC / DC superimposition electrolysis, and Duty electrolysis, but the electrolysis method is not particularly limited and any electrolysis method may be used. Further, it is preferable to perform washing with water at least once after the anodizing treatment. By washing with water, the anodizing liquid adhering to the aluminum parts is removed, and even if the treatment liquid that could not be removed remains, the concentration becomes thin and the next step is started. It is possible to reduce the amount of contamination. The water used for washing is preferably water with few impurities such as ion-exchanged water and pure water, but is not particularly limited.

3. 3. Coloring Step Coloring of the anodized film is performed by immersing the anodized film in an aqueous solution containing a colorant. As the colorant, a colorant generally sold such as a colorant for an anodic oxide film can be used. The water to be mixed with the colorant is preferably water having few impurities, but is not particularly limited. Conditions such as the concentration, temperature, and immersion time of the coloring liquid are not particularly limited because they differ depending on the shade to be colored. Generally, a manufacturer selling a colorant specifies preferable conditions for each color shade, so that the colorant may be colored according to the specified conditions.

4. Pre-sealing treatment step The pre-sealing treatment step is performed by immersing the colored anodic oxide film in an aqueous solution containing a surfactant as a pretreatment for the sealing treatment. As the surfactant, a surfactant that becomes an anion when dissociated in water is used. According to the findings of the present inventors, it is presumed that such an anionic surfactant can suppress the change in charge of the anodic oxide film from positive to negative. Anionic surfactants are more preferred as the surfactants. For example, anionic surfactants such as a carboxylate type, a sulfonate type, and a sulfate ester salt type are more preferable, and these may be combined. Further, as the surfactant, a carboxylate type commercially available under the trade name Lavanol CK of Matsumoto Yushi Pharmaceutical Co., Ltd. can also be used.

The concentration of the surfactant is preferably 1 g / L or more, more preferably 7.5 g / L or more. When the content is 1 g / L or more, the surfactant is likely to adhere to the film, and the effect of suppressing decolorization at the time of sealing is easily obtained. When the amount is 7.5 g / L or more, the amount of the surfactant taken into the pores is further increased, and the pores that cannot be taken in are substantially eliminated, so that the decolorization of the colorant can be sufficiently suppressed. Become. The concentration of the surfactant is preferably 100 g / L or less. When the concentration is 100 g / L or less, the aqueous solution can be easily agitated even if the concentration is high, and further, the mixing into the next step due to taking out is reduced.

The time for immersing the anodic oxide film in an aqueous solution containing a surfactant, which is a pretreatment liquid for sealing, is not particularly limited, but is preferably 1 to 20 minutes in consideration of productivity. When the film is immersed, the surfactant is rapidly adsorbed on the film, and after that, the surfactant is only replaced and the amount of the adsorbed surfactant does not change, so the effect of the immersion time. Is not seen.

The temperature of the sealing pretreatment liquid is preferably 10 to 70 ° C., and more preferably 20 to 50 ° C. in consideration of productivity, energy consumption by heating, and control of liquid concentration. When the liquid temperature is 70 ° C. or lower, the hydration reaction of the film is suppressed, so that it is possible to prevent the colorant attached when the film is dissolved during the hydration reaction from elution and decolorization. .. Further, by suppressing the hydration reaction, it is possible to facilitate the subsequent pore-sealing treatment reaction. When the liquid temperature is 10 ° C. or higher, the pre-sealing treatment can be easily performed, the energy consumption required for cooling the anodic oxide film in the pre-sealing treatment can be suppressed, and further, regardless of the type of surfactant. , It is possible to prevent the surfactant from solidifying or precipitating.

5. Sealing treatment step The sealing treatment step is performed by adhering the sealing treatment liquid to the anodic oxide film. For example, the aluminum or aluminum alloy member on which the anodized film is formed is immersed in an alkaline aqueous solution, or the alkaline aqueous solution is sprayed or applied to the member to seal the member. It is preferable to perform the sealing treatment by spraying or coating, whereby the sealing treatment can be partially performed and even a large part does not need to be immersed, so that the effect of not requiring a large tank can be expected. ..

As the alkaline aqueous solution, an alkaline aqueous solution containing lithium ions is preferable. As the reagent serving as a lithium ion source, lithium hydroxide, lithium carbonate, lithium silicate, lithium sulfate, lithium chloride, lithium phosphate, and hydrates thereof can be used. Of these, lithium hydroxide and lithium carbonate, whose aqueous solution is alkaline and non-toxic, are preferable.

The lithium ion concentration of the pore-sealing treatment liquid needs to be 0.02 to 20 g / L, preferably 0.08 to 10 g / L. When it is 0.02 g / L or more, the sealing reaction proceeds in a short time, and the sealing can be performed. When it is 20 g / L or less, rapid dissolution of the film can be prevented and decolorization can be suppressed.

The temperature of the sealing liquid is preferably 10 to 65 ° C, more preferably 25 to 50 ° C. When the temperature is 10 ° C. or higher, the sealing reaction proceeds in a short time, and the sealing can be performed. When the temperature is 65 ° C. or lower, excessive pore-sealing reaction can be suppressed and decolorization can be suppressed by preventing rapid dissolution of the film.

The treatment time is preferably 0.5 to 5 minutes. When it is 0.5 minutes or more, the pores of the film can be reliably closed and a film having high corrosion resistance can be formed. When it is 5 minutes or less, excessive dissolution of the film can be prevented and decolorization can be suppressed.

The pH of the sealing liquid is preferably 10.5 or higher, more preferably 11 or higher, and even more preferably 12 or higher. When it is 10.5 or more, the sealing reaction occurs, so that the sealing process can be performed at a low temperature and in a short time. Since the pH differs depending on the lithium ion source, the pH can be adjusted by using an acid such as sulfuric acid, oxalic acid, or chromic acid, or a base such as sodium hydroxide, sodium carbonate, or sodium fluoride.

After the sealing treatment, the aluminum or aluminum alloy member having high corrosion resistance can be produced without changing the color tone of the film by washing with water or hot water again and drying with an air blower or a dryer.

As described above, the step of forming the anodic oxide film having pores, the step of coloring the pores of the anodic oxide film, and the surfactant that becomes an anion when the pores of the colored anodic oxide film are dissociated in water. By performing a pretreatment step of contacting with the contained aqueous solution and a step of sealing the pores of the anodic oxide film contacted with the surfactant with an alkaline aqueous solution, the sealing treatment can be performed for a short time at a low temperature. Even in the sealing treatment with an aqueous solution, the decolorization of the colorant from the pores of the anodic oxide film during the sealing treatment can be suppressed, and a good appearance can be obtained.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Further, with respect to the anodic oxide films produced in Examples and Comparative Examples, it was determined by the following method whether or not the decolorization of the anodic oxide film could be suppressed.

[Evaluation methods]
SCI (measured value of color including specular reflected light) was measured with a spectrocolorimeter CM-700d manufactured by Konica Minolta Co., Ltd. for the anodized film before and after the sealing treatment, and the sealing was performed. The color difference ΔE was calculated from the SCI value before the pretreatment and the SCI value after the sealing treatment. The smaller the value of ΔE, the more there is no difference in color, that is, no bleaching has occurred. In the present invention, the value (ΔE = 11.9) of the test piece obtained by sealing with an alkaline aqueous solution containing lithium ions without performing the sealing pretreatment of the present invention after coloring the anodic oxide film is used as a reference. If it is 25% or more smaller than this (ΔE = 8.9 or less), it is judged that decolorization is suppressed, and if it is 50% or more smaller (ΔE = 6.0 or less), it is decolorized. It was judged that the inhibitory effect was high. In the evaluation results in the test examples described later, when ΔE = 8.9 or less, it was described as ◯, when ΔE = 6.0 or less, it was described as ⊚, and in other cases, it was described as × as having no effect.

In addition, in order to confirm whether the anodic oxide film was sealed, the surface of the anodic oxide film after the sealing treatment was observed with an electron microscope. Usually, when the sealing treatment described in Patent Document 1 is performed, a compound of lithium and aluminum mainly composed of LiH (AlO ₂ ) _{2.5H 2O} and a hydrate of aluminum oxide are generated in the pores of the anodized film. However, those compounds overflowing from the pores form flaky substances on the surface layer of the film (Fig. 1). Furthermore, since the pore-sealing reaction proceeds particularly in the vicinity of the surface layer of the anodic oxide film, the columnar structure called a cell in the anodic oxide film changes to a granular structure formed of the above compound in the vicinity of the surface layer of the anodic oxide film. (Fig. 2). This time, it was determined whether the pores were sealed based on whether or not this flaky substance was formed on the surface of the anodic oxide film.

In the test example, A1050 material was used as the object to be treated in order to clearly measure the color change. Since this material contains almost no alloy components, a nearly colorless film can be formed, and the color change when colored is easy to understand, so it was used, but similar results can be obtained with other aluminum and aluminum alloy materials.

Example 1: [Investigation of the effect of presealing liquid concentration]
Aluminum alloy A1050 material was used as a test piece. A test piece was immersed in a 200 g / L sulfuric acid bath as an anode, and a direct current was applied for 10 minutes at a current density of 1.5 A / dm ² to prepare a 5 μm anodic oxide film. Then, a 10 g / L aqueous solution (55 ° C.) in which the colorant TACRED-SCH (Red 106) manufactured by Okuno Pharmaceutical Industry Co., Ltd. was dissolved was prepared, and the test piece was immersed for 10 minutes for coloring. Ravanol CK manufactured by Matsumoto Yushi Seiyaku Co., Ltd. was used as the anionic surfactant to be added to the sealing pretreatment liquid, and an aqueous solution was prepared so as to have a concentration of 0.1 to 30 g / L. The temperature of this presealing liquid was fixed at 25 ° C., and the test piece was immersed therein for 10 minutes. Then, the test piece was immersed in a sealing liquid at pH 13 and 25 ° C. containing 1.6 g / L of lithium ion for 1 minute to perform the sealing treatment.

The test piece before the sealing pretreatment and the test piece after the sealing treatment were measured with a spectrocolorimeter to calculate the color difference ΔE. The results are shown in Table 1 and FIG. When the concentration of the surfactant was 1 g / L or more, the color difference ΔE was reduced by 25% or more, and when the concentration was 7.5 g / L or more, the value was reduced by 50% or more. On the other hand, when the concentration of the surfactant was smaller than 1 g / L, the surfactant component could not be sufficiently adhered to the film, and the decolorization became large at the time of sealing. It was also confirmed that the film was sealed at any concentration.

Further, in this example, the decolorization of the test piece was visually determined when the concentration of the surfactant was 0.1 g / L. The results are shown in FIG. It can be seen that the colorant is decolorized after the sealing treatment as compared with before the sealing pretreatment.

Example 2: [Investigation of the effect of immersion time in the presealing liquid]
Aluminum alloy A1050 material was used as a test piece. A test piece was immersed in a 200 g / L sulfuric acid bath as an anode, and a direct current was applied for 10 minutes at a current density of 1.5 A / dm ² to prepare a 5 μm anodic oxide film. Then, a 10 g / L aqueous solution (55 ° C.) in which the colorant TACRED-SCH (Red 106) manufactured by Okuno Pharmaceutical Industry Co., Ltd. was dissolved was prepared, and the test piece was immersed for 10 minutes for coloring. Ravanol CK manufactured by Matsumoto Yushi Seiyaku Co., Ltd. was used as an anionic surfactant to be added to the sealing pretreatment liquid, and an aqueous solution was prepared so as to have a concentration of 10 g / L. The temperature of this pretreatment liquid was fixed at 25 ° C., and the test piece was immersed therein for 1 to 20 minutes. Then, the test piece was immersed in a sealing liquid at pH 13 and 25 ° C. containing 1.6 g / L of lithium ion for 1 minute to perform the sealing treatment.

The test piece before the sealing pretreatment and the test piece after the sealing treatment were measured with a spectrocolorimeter to calculate the color difference ΔE. The results are shown in Table 2 and FIG. It was confirmed that the color difference was reduced by 50% or more at any of the immersion times, and that the holes were also sealed. From this, it was found that the immersion time in the pretreatment liquid does not affect the effect of the present invention because the surfactant quickly adheres to the film. In the case of industrial production, since the jig to which the parts are attached is often transported by a machine, it is difficult to move quickly, and it is preferable to immerse for at least 1 minute.

Further, in this example, the decolorization of the test piece was visually determined when the immersion time in the surfactant was 7 minutes. The results are shown in FIG. It can be seen that the decolorization of the colorant is suppressed after the sealing treatment as compared with that before the sealing pretreatment.

Example 3: [Investigation of the effect of temperature on the presealing liquid]
Aluminum alloy A1050 material was used as a test piece. A test piece was immersed in a 200 g / L sulfuric acid bath as an anode, and a direct current was applied for 10 minutes at a current density of 1.5 A / dm ² to prepare a 5 μm anodic oxide film. Then, a 10 g / L aqueous solution (55 ° C.) in which the colorant TACRED-SCH (Red 106) manufactured by Okuno Pharmaceutical Industry Co., Ltd. was dissolved was prepared, and the test piece was immersed for 10 minutes for coloring. Ravanol CK manufactured by Matsumoto Yushi Seiyaku Co., Ltd. was used as an anionic surfactant to be added to the sealing pretreatment liquid, and an aqueous solution was prepared so as to have a concentration of 10 g / L. The temperature of this pretreatment liquid was changed at 10 to 80 ° C., and the test piece was immersed in it for 10 minutes. Then, the test piece was immersed in a sealing liquid at pH 13 and 25 ° C. containing 1.6 g / L of lithium ion for 1 minute to perform the sealing treatment.

The test piece before the sealing pretreatment and the test piece after the sealing treatment were measured with a spectrocolorimeter to calculate the color difference ΔE. The results are shown in Table 3 and FIG. It was found that the color difference was reduced by 25% or more when the temperature of the presealing liquid was 10 to 70 ° C., and 50% or more when the temperature was 10 to 55 ° C. When the liquid temperature exceeds 70 ° C., a hydration reaction of the film (dissolution of the film) occurs, which adversely affects the decolorization and the subsequent sealing treatment. Cooling the pretreatment liquid consumes a large amount of energy, and depending on the type of the surfactant, it tends to solidify or precipitate, so 10 ° C. or higher is preferable.

Example 4: [Effects by type of surfactant]
Aluminum alloy A1050 material was used as a test piece. A test piece was immersed in a 200 g / L sulfuric acid bath as an anode, and a direct current was applied for 10 minutes at a current density of 1.5 A / dm ² to prepare a 5 μm anodic oxide film. Then, a 10 g / L aqueous solution (55 ° C.) in which the colorant TACRED-SCH (Red 106) manufactured by Okuno Pharmaceutical Industry Co., Ltd. was dissolved was prepared, and the test piece was immersed for 10 minutes for coloring. Ravanol CK of Matsumoto Oil & Fats Co., Ltd. as an anionic surfactant, Marpon DPE-0828 of Matsumoto Oil & Fats Co., Ltd. as a nonionic surfactant, amphoteric interface As the activator, three types of Marpo Vista MLS manufactured by Matsumoto Yushi Seiyaku Co., Ltd. were used, and an aqueous solution was prepared so that the concentration of each was 10 g / L. The temperature of this pretreatment liquid was fixed at 25 ° C., and the test piece was immersed therein for 10 minutes. Then, the test piece was immersed in a sealing liquid at pH 13 and 25 ° C. containing 1.6 g / L of lithium ion for 1 minute to perform the sealing treatment.

The test piece before the sealing pretreatment and the test piece after the sealing treatment were measured with a spectrocolorimeter to calculate the color difference ΔE. The results are shown in Table 4. It was found that the color difference was reduced by 50% or more only when the anionic surfactant was used, and that the nonionic surfactant and the amphoteric surfactant had no effect. Anodized surfactants can suppress the change in charge from positive to negative in the anodized film and suppress decolorization, but nonionic surfactants and amphoteric surfactants do not change the alumite film and suppress decolorization. No effect.

Claims (4)

Anodizing process to form anodized film with holes in aluminum and aluminum alloy material,
A coloring step of coloring the pores of the anodic oxide film and
A pretreatment step for sealing, in which the pores of the colored anodized film are brought into contact with an aqueous solution (not containing phosphate ions) containing a surfactant that becomes an anion when dissociated in water.
It includes a sealing treatment step of sealing the pores of the anodic oxide film brought into contact with the surfactant with an alkaline aqueous solution.
The surfactant is an anionic surfactant,
The concentration of the aqueous solution containing the surfactant is 1 g / L or more, and the concentration is 1 g / L or more.
The temperature of the aqueous solution containing the surfactant is 10 to 70 ° C.
A method for manufacturing an anodic oxide film. The first aspect of claim 1, wherein the surfactant is a surfactant consisting of any one of a carboxylate-type, a sulfonate-type, and a sulfate ester-type anionic surfactant, or a combination thereof. A method for manufacturing an anodic oxide film. The method for coloring and sealing an anodic oxide film according to claim 1, wherein the surfactant is a carboxylate type. The method for producing an anodic oxide film according to any one of claims 1 to 3, wherein the alkaline aqueous solution contains lithium ions.

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