JP5149590B2 - Method for producing surface-treated aluminum material - Google Patents

Description

  The present invention relates to a method for producing a surface-treated aluminum material suitably used for an aluminum product to be bonded.

  Various surface treatments are performed on aluminum materials and aluminum alloy materials used in aluminum products that are used by being bonded to electrical products, furniture, decorations, building materials, and the like in order to enhance adhesion. For example, as such a base treatment, there is a method of forming a nonporous anodized film on the surface of an aluminum material as disclosed in Patent Document 1 and Patent Document 2.

  However, simply forming a nonporous anodic oxide film on the surface of an aluminum material may result in insufficient adhesion. When the adhesiveness is insufficient, the corrosion resistance when used in a harsh environment becomes insufficient, and the reliability of the product may be impaired.

  Therefore, a manufacturing method has been proposed in which the electrolytic treatment process for forming the nonporous anodic oxide film is continuously performed in multiple stages, thereby forming a dense nonporous anodic oxide film in multiple layers and improving the corrosion resistance. .

However, even if the surface treatment of the aluminum material is performed by the multi-stage electrolytic treatment, the adhesion may be insufficient.
JP-A-8-283990 JP 2003-147550 A

  This invention is made | formed in view of the said situation, and it aims at providing the manufacturing method of the surface treatment aluminum material which has a nonporous anodic oxide film excellent in adhesiveness.

In order to achieve the above object, the present invention employs the following configuration. That is,
The manufacturing method of the surface treatment aluminum material of this invention manufactures the surface treatment aluminum material which forms a nonporous anodic oxide film on the surface of the said aluminum material by performing the electrolytic treatment process which electrolyzes aluminum material in electrolyte solution In the method, the electrolytic treatment step is continuously performed twice or more, and the electrolytic treatment step continuously performed twice or more includes a low-temperature electrolytic treatment step in which the liquid temperature of the electrolytic solution is less than 45 ° C. , and electrolysis Including a high-temperature electrolytic treatment step in which the liquid temperature is 45 ° C. or more, and performing the low-temperature high-temperature electrolytic treatment process in which the low-temperature electrolytic treatment step and the high-temperature electrolytic treatment step are successively performed in this order at least once. Features.

  In the method for producing a surface-treated aluminum material of the present invention, it is preferable that at least one electrolytic treatment step among the electrolytic treatment steps uses an alkaline electrolytic solution having a pH of 9 or more as the electrolytic solution.

  According to said structure, the manufacturing method of the surface treatment aluminum material which has a nonporous anodic oxide film excellent in adhesiveness can be performed.

  Hereinafter, an example of the manufacturing method of the surface treatment aluminum material which is embodiment of this invention is demonstrated using FIG. First, the manufacturing apparatus will be described.

(manufacturing device)
As shown in FIG. 1, the apparatus for producing a surface-treated aluminum material according to an embodiment of the present invention was filled with an unwinder 4, 17 transport rolls 3, a winder 5, and an electrolytic solution 2. The electrolysis treatment tank 1, the power supply roll 7, the DC power sources E ₁ , E ₂ , E ₃ , E ₄ and the cathode C made of an insoluble conductive material are included. A roll-shaped aluminum material 6 is set in the unwinding machine 4 of this manufacturing apparatus, and the drawn aluminum material 6 is subjected to electrolytic treatment in the electrolytic treatment tank 1 continuously, whereby the surface of the aluminum material 6 is obtained. A non-porous anodic oxide film is formed thereon, and finally the surface-treated aluminum material is wound up by a winder 5.

The electrolytic treatment tank 1 is composed of four electrolytic treatment tanks arranged in series from upstream to downstream of the manufacturing apparatus. The four electrolytic treatment tanks are referred to as a first electrolytic treatment tank 1a, a second electrolytic treatment tank 1b, a third electrolytic treatment tank 1c, and a fourth electrolytic treatment tank 1d, respectively.
The four electrolytic treatment tanks 1a, 1b, 1c, and 1d are spaced apart from each other. Therefore, the distance d that separates the electrolytic treatment tanks 1a, 1b, 1c, and 1d corresponds to the interruption time t corresponding to the interruption processes ma, mb, and mc.

A feeding roll 7 is connected to the anode side of the DC power supplies E ₁ , E ₂ , E ₃ , E ₄ , and the aluminum material 6 is fed to each electrolytic treatment tank 1 a, 1 b, 1 c, via the feeding roll 7. It connects so that it may become an anode within 1d.
On the other hand, the cathode side of the DC power supplies E ₁ , E ₂ , E ₃ , E ₄ is connected to a cathode C made of an insoluble conductive material disposed in each electrolytic treatment tank 1a, 1b, 1c, 1d.
Therefore, the DC power source _{E 1, E 2, E 3} , the voltage _V ka of _{E 4, V kb, V kc} , by adjusting the _{V kd,} the voltage _{V ka, V kb, V kc} , the _{V kd} the It can be applied between the anode made of the aluminum material 6 and the cathode C made of the insoluble conductive material.

The aluminum material 6 can be aluminum or an aluminum alloy, and is not particularly limited. Specifically, for example, pure aluminum 1000 series alloy, Al-Cu series, Al-Cu-Mg series 2000 series alloy, Al-Mn series 3000 series alloy, Al-Si series 4000 series alloy, Al -Mg-based 5000 alloy, Al-Mg-Si-based 6000-based alloy, Al-Zn-Mg-Cu-based, Al-Zn-Mg-based 7000-based alloy, Al-Fe-Mn-based 8000-based alloy, etc. And casting alloys such as forming alloys, structural alloys, electrical alloys, AC1A, AC2A, AC3A, AC4B, and the like are used.
As the aluminum material, those obtained by subjecting the above alloy to various tempering treatments such as solution treatment and aging treatment can be used. Further, a clad material obtained by cladding these aluminum alloys on the surface can also be used. Moreover, even if it is a processed material which gave press-molding processing etc. previously, it may be an unprocessed board | plate material, an extruded material, and a cast product. In the present invention, among these alloys, 1000 series alloys, 3000 series alloys, and 5000 series alloys are preferable.

  The aluminum material 6 is preferably pretreated before the electrolytic treatment process. The pretreatment refers to a treatment that removes oil and fat adhering to the surface of the aluminum material 6 or removes a heterogeneous oxide film formed on the surface of the aluminum material 6. is not. Specifically, for example, the aluminum material 6 is subjected to a degreasing treatment with a weak alkaline degreasing solution, then subjected to alkali etching with an aqueous sodium hydroxide solution, and desmutting in an aqueous nitric acid solution, A method of performing acid cleaning after the degreasing treatment can be appropriately selected and used.

(Manufacturing process)
Next, the manufacturing method of the surface treatment aluminum material which is embodiment of this invention is demonstrated using FIG.
The electrolytic treatment step k includes a first electrolytic treatment step ka, a second electrolytic treatment step kb, a third electrolytic treatment step kc, and a fourth electrolytic treatment step in the four electrolytic treatment tanks 1a, 1b, 1c, and 1d of the manufacturing apparatus. It is roughly constituted by kd.
An interruption step m is inserted into the electrolytic treatment step k. Specifically, interruption steps ma, mb, mc are inserted between the respective electrolytic treatment steps ka, kb, kc, kd.
Further, the liquid temperatures of the electrolytic solutions 2a, 2b, 2c, and 2d in the respective electrolytic treatment steps ka, kb, kc, and kd are set as T _ka , T _kb , T _kc , and T _kd , respectively.

(Electrolytic treatment process)
The electrolytic treatment step k is an electrolytic treatment step of forming a nonporous anodized film on the surface of the aluminum material 6 by subjecting the aluminum material 6 to electrolytic treatment in the electrolytic solution 2. In the electrolytic solution 2, the electrolytic treatment is an energization treatment in which the aluminum material 6 is connected to the anode, the insoluble counter electrode is connected to the cathode, a voltage is applied, and a direct current is passed.

The nonporous anodic oxide film is a film made of aluminum oxide formed on the surface of the aluminum material 6 by the above-described energization treatment, and the porosity of the holes formed on the surface of the film is 5 % Or less. In a film having a porosity of 5% or less, the number of holes is small or the size of the hole diameter is small, so that the adhesion with the coating material can be improved.
In addition, the said porosity is an area ratio of the hole which can be observed when the surface of an anodized film is observed using a transmission electron microscope at a magnification of 50,000 times.

As the current, a direct current having a current density of about 0.2 to 20 A / dm ² is used.
The voltage is about 5 to 300V, preferably about 20 to 100V. When a direct current is used, there is a proportional relationship that the thickness of the nonporous anodic oxide film formed by applying a voltage of 1 V is about 1.4 nm. In order to form, it is preferable to use an applied voltage in the above range.
In addition, from the viewpoint of a power supply device and the like, it is preferable to set the voltage to 100 V or less. In the method for producing a surface-treated aluminum material that is an embodiment of the present invention, a nonporous material having excellent adhesion even at such a low voltage. An anodized film can be formed.
Moreover, it is preferable that the total electrolysis time of all the electrolytic treatment steps k is about several seconds to 10 minutes.

(First electrolytic treatment step ka)
Specifically, first, the aluminum material 6 is set in the unwinder 4 and the drawing is started. The drawn aluminum material 6 is conveyed by the conveyance roll 3.
About the conveyed aluminum material 6, the 1st electrolytic treatment process ka is made | formed by the 1st electrolytic treatment tank 1a. The liquid temperature of the electrolytic solution 2a is set to _Tka . Then, it is pulled out from the electrolytic treatment tank 1a and the first interruption step ma is performed. The interruption time t in the interruption process m is 1.5 seconds, and the interruption time t in each interruption process is also 1.5 seconds.

The interruption step is an interruption step in which the interruption time t for interrupting the electrolytic treatment is 0.3 seconds or more, more preferably 0.8 seconds or more. By performing the interruption process, the surface state of the nonporous anodic oxide film formed by the electrolytic treatment process can be stabilized, and the effect of modifying the surface of the nonporous anodic oxide film can be improved. For example, local heat generation on the surface of the aluminum material 6 or concentration of the electrolyte anion is made uniform, so that the surface state can be stabilized and the electrolysis in the next electrolytic treatment tank can be performed uniformly. it can.
When the interruption time t is less than 0.3 seconds, the surface state of the nonporous anodic oxide film formed by the electrolytic treatment process cannot be stabilized and a defective portion may be generated. Furthermore, a case where a porous oxide film is formed on a part of the surface occurs.
When the interruption time t exceeds 30 seconds, the effect of interruption is not improved so much, and the time required for manufacturing becomes long, which is not preferable from the viewpoint of manufacturing cost, production efficiency, and the like.

(Second electrolytic treatment process kb)
Further, the aluminum material 6 subjected to the interruption process ma is subjected to the second electrolytic treatment process kb in the second electrolytic treatment tank 1b and then pulled up from the electrolytic treatment tank 1b to perform the second interruption process mb. . The liquid temperature of the electrolytic solution 2b is set to T _kb .

(Third electrolytic treatment step kc)
Further, the aluminum material 6 subjected to the interruption process mb is subjected to the third electrolytic treatment process kc in the third electrolytic treatment tank 1c, and then pulled up from the electrolytic treatment tank 1c to perform the third interruption process mc. . The liquid temperature of the electrolytic solution 2c is set to _Tkc .

(4th electrolytic treatment step kd)
Finally, after the fourth electrolytic treatment tank 1d has been subjected to the fourth electrolytic treatment step kd for the aluminum material 6 subjected to the interruption step mc, the aluminum material 6 has been lifted from the electrolytic treatment bath 1d and transported by the transport roll 3. It is wound up by a winder 5 and manufactured as a surface-treated aluminum material. The liquid temperature of the electrolytic solution 2d is set to T _kd .
In addition, the electrolytic solution 2d is adjusted to pH 9 by adding sodium hydroxide to a phosphate aqueous solution.

(Electrolytic solution 2)
Examples of the electrolyte used in the electrolytic solution 2 include boric acid and borate (for example, sodium borate, potassium borate, ammonium borate, and sodium tetraborate) that are electrolytes that form a nonporous anodic oxide film. Phosphate (eg, sodium phosphate, potassium phosphate, ammonium phosphate, ammonium hydrogen phosphate, etc.), adipate (eg, ammonium adipate), phthalate (eg, potassium hydrogen phthalate), silicic acid Salt (eg, potassium silicate, sodium silicate, aluminum silicate, magnesium silicate, calcium magnesium silicate, sodium metasilicate, lithium silicate, etc.), benzoate (eg, ammonium benzoate), tartrate (eg, , Ammonium tartrate, potassium tartrate, sodium potassium tartrate, tartaric acid Thorium, potassium hydrogen tartrate), malonate (eg, ethyl malonate), citrate (eg, sodium citrate, potassium citrate) and the like in an aqueous solution in which one or more electrolytes are dissolved Etc. can be used.
Among the electrolytes, phosphates and silicates form non-porous anodic oxide coatings, phosphate anions and silicate anions bind to the coating surface, improve adhesion and corrosion resistance, and manufacture It is preferable in terms of cost.

It is preferable that the electrolytic solution 2 has a pH of 9 or more. It is desirable to use an alkaline electrolyte having a pH of 10 or more, more preferably a pH of 11 or more.
When an alkaline electrolyte having a pH of 9 or more is used as the electrolyte 2, local dissolution can be caused on the surface of the nonporous anodic oxide film, and hydroxyl or A reactive group composed of an electrolyte component can be formed. The local dissolution described above and the reactive group formed on the surface can enhance the adhesion to the coating material.

  In addition, the electrolytic treatment process using the electrolytic solution 2 having a pH of 9 or more may be at least once, and the electrolytic solution 2 having a pH of 2 to 12 can be used in the remaining electrolytic treatment process. This is because the surface modification effect can be caused by performing treatment with such an alkaline electrolyte at least once. Note that such an alkaline electrolytic solution may be used in all electrolytic treatment steps.

Moreover, it is not preferable to use an alkaline electrolyte having a pH of 13 or higher because the cortical dissolution of the nonporous anodic oxide film will be remarkable and the adhesion to the coating material will be deteriorated.
The electrolytic solution 2 can be adjusted to an alkaline electrolytic solution by adding sodium hydroxide or the like to an aqueous solution in which the electrolyte is dissolved.
Furthermore, the electrolyte concentration in the electrolytic solution 2 can be selected within the range of the saturation concentration of the electrolyte used from 2% by mass.

(Low temperature-high temperature electrolytic treatment process)
The first half of the electrolytic treatment process is a low temperature electrolytic treatment process in which the liquid temperature of the electrolytic solution 2 is less than 45 ° C., and the subsequent electrolytic treatment process is a high temperature electrolytic treatment process in which the liquid temperature of the electrolytic solution 2 is 45 ° C. or higher. Is referred to as a low temperature-high temperature electrolysis process.

  The first half electrolytic treatment is, for example, of the four electrolytic treatment tanks, the first electrolytic treatment tank may be the first half electrolytic treatment tank, the second electrolytic treatment tank may be the first half electrolytic treatment tank, The electrolytic treatment tank 3 may be the first half electrolytic treatment tank.

In the low temperature-high temperature electrolytic treatment process, first, a low temperature electrolytic treatment step is performed in which the electrolytic solution 2 is subjected to electrolytic treatment at a liquid temperature of less than 45 ° C., and the surface of the aluminum material 6 is uniform and dense with excellent adhesion. A non-porous anodic oxide film is formed, and then the surface of the non-porous anodic oxide film is locally dissolved by performing a high-temperature electrolytic treatment step in which the temperature of the electrolytic solution 2 is 45 ° C. or higher. The surface should have excellent adhesion.
Moreover, the said high temperature electrolysis process process can also form the reactive group which consists of a hydroxyl group or an electrolyte component on the surface of the said membrane | film | coat. Such a reactive group comprising a hydroxyl group or an electrolyte component further improves the adhesion.
Therefore, it is more preferable that the final step of the electrolytic treatment step k is a high temperature electrolytic treatment step of 45 ° C. or higher.

The liquid temperature of the electrolytic solution 2 in the low-temperature electrolytic treatment step is preferably a low temperature of 20 ° C. or higher and lower than 45 ° C., and more preferably 20 ° C. or higher and 30 ° C. or lower. When the liquid temperature is lower than 20 ° C., the electrolytic solution component is deposited.
The liquid temperature of the electrolytic solution 2 in the high-temperature electrolytic treatment step is preferably a high temperature of 45 ° C. or higher and lower than 80 ° C., and more preferably 60 ° C. or higher and lower than 80 ° C. This is because when the liquid temperature is lower than 80 ° C., the electrolytic solution 2 boils and cannot be used as the electrolytic solution 2 for electrolytic treatment.

The low temperature-high temperature electrolytic treatment process may be at least one in the electrolytic treatment step k, and may be at any stage of the electrolytic treatment step k.
For example, the initial stage may be T _ka = 30 ° C., T _kb = 45 ° C., T _kc = 45 ° C., T _kd = 45 ° C., T _ka = 30 ° C., T _kb = 30 ° C., There may be intermediate stages such as T _kc = 45 ° C. and T _kd = 45 ° C., such as T _ka = 30 ° C., T _kb = 30 ° C., T _kc = 30 ° C., T _kd = 45 ° C. It may be the final stage.

The low temperature-high temperature electrolytic treatment process may be at least one in the electrolytic treatment step k, and may be two or more.
For example, the liquid temperature of the electrolytic solution 2 is set such that T _ka = 30 ° C., T _kb = 45 ° C., T _kc = 30 ° C., and T _kd = 45 ° C., and two low-temperature high-temperature electrolytic treatment processes are provided. It doesn't matter.

In addition, about the surface treatment aluminum material obtained in this way, it is good also as a surface treatment aluminum material which further modified the surface state by performing the said manufacturing method in multiple times.
Moreover, there is no restriction | limiting in the number of the electrolytic treatment tanks 1. FIG. For example, the manufacturing method may be performed with six or more electrolytic treatment tanks 1.
Hereinafter, effects of the embodiment of the present invention will be described.

  In the method for producing a surface-treated aluminum material according to an embodiment of the present invention, first, a low-temperature electrolytic treatment step in which the temperature of the electrolytic solution is less than 45 ° C. is performed, and a uniform and dense nonporous anode is formed on the surface of the aluminum material. After forming an oxide film and making the surface of the aluminum material a highly durable surface, a high-temperature electrolytic treatment step is performed in which the temperature of the electrolytic solution is 45 ° C. or higher, and the surface of the nonporous anodic oxide film is localized. And a reactive group composed of a component of the electrolytic solution or a hydroxyl group is formed to make the surface excellent in adhesiveness. As a result, a two-layer structure consisting of a uniform and dense nonporous anodic oxide film excellent in durability and a surface layer excellent in adhesiveness can be formed.

  Since the method for producing a surface-treated aluminum material according to an embodiment of the present invention is configured to perform the electrolytic treatment step twice or more, a multilayer dense and uniform non-porous anodic oxide film can be formed, and adhesion can be improved. , Its corrosion resistance can be improved.

  Since the manufacturing method of the surface treatment aluminum material which is embodiment of this invention is the structure which performs an electrolytic treatment process after performing an interruption process, the effect which modifies the surface of a nonporous anodized film can be improved. For example, the local heat generation on the surface of the aluminum material or the concentration of the electrolyte anion can be made uniform, so that the surface state can be stabilized and the electrolysis in the next electrolytic treatment tank can be performed uniformly. .

Since the method for producing a surface-treated aluminum material according to an embodiment of the present invention uses an alkaline electrolyte having a pH of 9 or more as an electrolyte, it causes local dissolution on the surface of the nonporous anodic oxide film, and a hydroxyl group or By forming a reactive group composed of an electrolyte component, the adhesiveness can be increased.
Hereinafter, the present invention will be specifically described based on examples. However, the present invention is not limited only to these examples.

Example 1
Using a JIS1100 aluminum alloy strip having a width of 1000 mm and a thickness of 0.3 mm as an aluminum material, using a 5% aqueous sodium hydroxide solution with a liquid temperature of 50 ° C., etching is performed for 10 seconds, and after washing with water for 10 seconds, room temperature is obtained. A 5% nitric acid aqueous solution was used for neutralization for 10 seconds, and a pretreatment was performed again with water for 10 seconds.

Next, the pretreated aluminum alloy strip was subjected to three-step electrolytic treatment using the manufacturing apparatus shown in FIG. 1 to obtain a surface-treated aluminum material having a nonporous anodized film.
In the three-stage electrolytic treatment, a low-temperature electrolytic treatment step in which the liquid temperature of the electrolytic solution is 30 ° C. is used as the first electrolytic treatment step, and a liquid temperature of the electrolytic solution is set to 30 ° C. in the second electrolytic treatment step. A low temperature electrolytic treatment step was used, and a high temperature electrolytic treatment step in which the temperature of the electrolytic solution was 45 ° C. was used as the third electrolytic treatment step.
As conditions for the electrolytic treatment, the current density of each tank was 3 A / dm ² , and the upper limit voltage was 100V. The interruption time in the interruption process was set to 0.3 seconds.
The electrolytic solution used in the electrolytic treatment step was a 2% sodium phosphate aqueous solution, and the electrolytic solution was adjusted to pH 3.0 by containing sodium hydroxide.

  The initial adhesion strength and porosity of the non-porous anodic oxide film of the surface-treated aluminum material thus obtained were examined as follows.

(Initial bond strength)
Two surface-treated aluminum materials having a width of 25 mm, a length of 150 mm, and a thickness of 1 mm are prepared, and an adhesive (EP190: trade name, manufactured by Cemedine) is applied to the surface of one surface-treated aluminum material at 0.3 g / m ^2. Then, another surface-treated aluminum material was laminated and adhered in the longitudinal direction and dried for 6 hours.

  The strength at which the adhesive surface of the sample peeled was measured by a T peel test, and the initial adhesive strength was evaluated. The initial adhesive strength was 115 MPa.

(Porosity)
Observe any surface of a non-porous anodized film of surface-treated aluminum material with a width of 25 mm, a length of 150 mm, and a thickness of 1 mm using a transmission electron microscope at a magnification of 50,000 and measure the area ratio of the holes did. The porosity was 0.3%.

(Examples 2 to 5)
For Examples 2 to 5, the same experiment as in Example 1 was performed.
Table 1 shows the experimental conditions and experimental results of Examples 1 to 5. In Table 1, No. 1 to 5 correspond to Examples 1 to 5, respectively.

As can be seen from Table 1, in Examples 1 to 5 (Nos. 1 to 5 in Table 1), the initial adhesive strength was 115 to 155 MPa, which was a very excellent practical value.
In Examples 3 to 5 (Nos. 3 to 5 in Table 1), two temperatures of 45 ° C. and 60 ° C. were used as the temperature of the electrolytic solution in the high-temperature electrolytic treatment process. As can be seen from a comparison between Example 2 (No. 2 in Table 1) and Example 3 (No. 3 in Table 1), by performing the temperature of the electrolytic solution in the high-temperature electrolytic treatment step in multiple stages, Initial bond strength was improved.

(Comparative Examples 1-3)
About Comparative Examples 1-3, it experimented similarly to Example 1 except not having performed high temperature electrolytic treatment.
Table 2 shows experimental conditions and experimental results of Comparative Examples 1 to 3. In Table 2, No. 1 to 3 correspond to Comparative Examples 1 to 3, respectively.

  As can be seen from Table 2, for Comparative Examples 1 to 3 (No. 1 to 3 in Table 2) that were not subjected to high-temperature electrolytic treatment, the initial adhesive strength was 55 to 68 MPa, a value that cannot be used at a practical level. showed that.

  As can be seen from the porosity data in Tables 1 and 2 being 0.1 to 0.7% and 5% or less, Examples 1 to 5 (Nos. 1 to 5 in Table 1). ) And Comparative Examples 1 to 3 (Nos. 1 to 3 in Table 2), all the anodized films formed on the surface of the surface-treated aluminum material are nonporous.

  The present invention relates to a method for producing a surface-treated aluminum material that is suitably used for an aluminum product to be bonded, and is applicable to industries that require a base treatment of the aluminum material to be bonded.

It is a figure explaining an example of the manufacturing method of the surface treatment aluminum material which is embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electrolytic treatment tank, 1a ... 1st electrolytic treatment tank, 1b ... 2nd electrolytic treatment tank, 1c ... 3rd electrolytic treatment tank, 1d ... 4th electrolytic treatment tank, 2 ... Electrolytic solution, 3 ... Conveyance roll, 4 ... Unwinder, 5 ... Winder, 6 ... Aluminum material, 7 ... Feed roll, k ... Electrolytic treatment step, ka ... First electrolytic treatment step, kb ... Second electrolytic treatment step, kc ... Third electrolysis Treatment step, kd ... fourth electrolytic treatment step, m ... interruption step, ma ... first interruption step, mb ... second interruption step, mc ... third interruption step, E ₁ , E ₂ , E ₃ , E ₄ ... DC power source, C ... Cathode made of insoluble conductive material.

Claims (2)

In the method for producing a surface-treated aluminum material, a non-porous anodized film is formed on the surface of the aluminum material by performing an electrolytic treatment step of electrolyzing the aluminum material in an electrolytic solution.
The electrolytic treatment step is performed continuously twice or more,
The electrolytic treatment step that is continuously performed twice or more includes a low temperature electrolytic treatment step in which the liquid temperature of the electrolytic solution is less than 45 ° C., and a high temperature electrolytic treatment step in which the liquid temperature of the electrolytic solution is 45 ° C. or more .
A method for producing a surface-treated aluminum material, wherein the low-temperature high-temperature electrolytic treatment process in which the low-temperature electrolytic treatment step and the high-temperature electrolytic treatment step are successively performed in this order is performed at least once .   The method for producing a surface-treated aluminum material according to claim 1, wherein at least one of the electrolytic treatment steps uses an alkaline electrolytic solution having a pH of 9 or more as the electrolytic solution.

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