WO2015015768A1

WO2015015768A1 - Treated surface aluminum material and manufacturing method therefor

Info

Publication number: WO2015015768A1
Application number: PCT/JP2014/003880
Authority: WO
Inventors: 達矢三村; 長谷川　真一; 幸翁本川
Original assignee: 株式会社Uacj
Priority date: 2013-08-01
Filing date: 2014-07-23
Publication date: 2015-02-05
Also published as: CN105408527B; KR20160040458A; TW201510233A; JP6563336B2; JPWO2015015768A1; TWI656223B; KR102155398B1; CN105408527A; MY177082A

Abstract

[Problem] To provide a treated surface aluminum material, on a portion of the surface of which a corrosion-resistant oxide film layer is formed and on the other areas of the surface of which a porous oxide film layer of excellent adhesiveness and closeness of adhesion is formed. [Solution] A treated surface aluminum material and a manufacturing method therefor. The treated surface aluminum material comprises an aluminum material, a monolayer structure corrosion resistant oxide film formed on a portion of the surface of the aluminum material, and a porous oxide film formed on the other areas of the surface. The corrosion resistant oxide film has a 10- 100 nm thickness and has specified FT-IR analysis characteristics. The porous oxide film is obtained from a 20-500 nm thick porous aluminum oxide film layer formed on the surface side and 3-30 nm barrier aluminum oxide film layer formed on the base side. Pores of 5-30 nm diameter are formed in the porous aluminum oxide film layer. The range of fluctuation in thickness in the overall porous oxide film formed on the surface of the aluminum material is within ±50% of the arithmetic mean thereof.

Description

Surface-treated aluminum material and method for producing the same

The present invention relates to a surface-treated pure aluminum material or aluminum alloy material (hereinafter referred to as “aluminum material”) and a method for producing the same, and more specifically, a corrosion-resistant oxide film layer having excellent corrosion resistance on a part of the surface. The present invention relates to a surface-treated aluminum material in which a porous oxide film layer having excellent adhesion and adhesion is formed at a portion of the surface where the corrosion-resistant oxide film layer is not formed and a method for producing the same.

Aluminum materials are lightweight, have appropriate mechanical properties, and have excellent characteristics such as aesthetics, moldability, and corrosion resistance, so they can be used in various containers, structural materials, mechanical parts, electronic parts, etc. Widely used. By applying a surface treatment to a part of these aluminum materials, functions such as corrosion resistance, abrasion resistance, resin adhesion, adhesion, hydrophilicity, water repellency, antibacterial properties, design properties, infrared radiation, high reflectivity, etc. Often added and improved.

For example, as a surface treatment method for improving corrosion resistance and wear resistance, anodizing treatment (so-called alumite treatment) is widely used. Specifically, as described in Non-Patent

Documents

1 and 2, an anodized film is formed by immersing an aluminum material in an acidic electrolytic bath and performing electrolytic treatment with a direct current. Accordingly, various processing methods have been proposed.

In particular, as a surface treatment method for improving resin adhesion, Patent Document 1 proposes an alkaline alternating current electrolysis method. That is, using an alkaline solution of a bath temperature 35 ~ 85 ° C., the time that the quantity of electricity exceeds 80C / dm ² at a current density of 4 ~ 50A / dm ^2, and performs an AC electrolysis process. As a result, a printed wiring board on which an oxide film having a thickness of 500 to 5000 mm is formed is obtained.

Japanese Patent Laid-Open No. 5-19001

In the conventional technology as described above, since the electrolytic treatment is performed by directly connecting to the aluminum material, the aluminum material itself becomes the electrode. Thus, the surface treatment is applied to the entire area where the aluminum material is in contact with the electrolytic solution.

When applying a surface treatment for imparting resin adhesion to a part of the aluminum material, the surface portion not subjected to the treatment is covered with a masking tape or the like. Since the surface treatment is performed on the uncoated portion, the resin adhesion is improved. However, since the portion where the coating is removed after the surface treatment is not subjected to the surface treatment, it is desirable that the resin adhesion is not given, but there is a disadvantage that the corrosion resistance cannot be obtained.

In this case, after a surface treatment for improving resin adhesion is performed on a part of the surface of the aluminum material, it is necessary to perform a surface treatment for imparting corrosion resistance to a portion not subjected to the surface treatment. Therefore, the portion subjected to the surface treatment for improving the resin adhesion is again coated and the second surface treatment is performed. For this reason, there is a problem that not only the cost is increased by performing the coating twice, but also a step of performing the second surface treatment is separately required, so that productivity is lowered.

As a result of repeated studies to solve the above-mentioned problems, the present inventors have formed a corrosion-resistant oxide film only on a specific portion, and a portion having no corrosion-resistant oxide film has a porous property having adhesion. The present invention has been completed by finding a surface-treated aluminum material on which a porous oxide film is formed, and a method for producing the surface-treated aluminum material that simultaneously forms the corrosion-resistant oxide film and the porous oxide film.

That is, the present invention according to claim 1 is formed at a site where the aluminum material, the corrosion-resistant oxide film having a single-layer structure formed on a part of the surface thereof, and the corrosion-resistant oxide film on the surface of the aluminum material are not formed. The corrosion-resistant oxide film has a thickness of 10 to 100 nm, the peak absorption wave number by FT-IR analysis is b (cm ⁻¹ ), and the peak absorption rate at the peak absorption wave number b Is a porous aluminum oxide film layer having a thickness of 20 to 500 nm, which satisfies the relationship of 1 ≦ a ≦ 95 and b ≧ 3a + 710, and is formed on the surface side. And a barrier type aluminum oxide film layer having a thickness of 3 to 30 nm formed on the substrate side. The porous aluminum oxide film layer has small holes with a diameter of 5 to 30 nm. In the entire porous oxide film formed on the surface of the aluminum material, the fluctuation width of the total thickness of the porous aluminum oxide film layer and the barrier type aluminum oxide film layer is an arithmetic average of the total thickness. The surface-treated aluminum material was characterized by being within ± 50% of the value.

According to a second aspect of the present invention, in the first aspect, the peak absorption wave number b (cm ⁻¹ ) is a peak wave number resulting from the strongest stretching vibration of Al—O, and appears in a range of 720 ≦ b ≦ 995. It was supposed to be.

In the third aspect of the present invention, the ratio of the total hole area of the small holes to the apparent surface area of the porous aluminum oxide film layer in the first or second aspect is 25 to 75%.

The present invention according to claim 4 uses an aluminum material electrode to be surface-treated, a counter electrode, and a conductive material connected to the aluminum material electrode, has a pH of 9 to 13 and a liquid temperature of 35 to 85 ° C., and By using an aqueous alkaline solution having a dissolved aluminum concentration of 5 ppm or more and 1000 ppm or less as an electrolytic solution and subjecting it to an alternating current electrolytic treatment under conditions of a frequency of 10 to 100 Hz, a current density of 4 to 50 A / dm ² and an electrolysis time of 5 to 60 seconds, A surface-treated aluminum material characterized by forming a porous oxide film on the surface of the facing aluminum material and simultaneously forming a corrosion-resistant oxide film on the surface of the aluminum material facing the conductive material connected to the aluminum material electrode. It was set as the manufacturing method.

In the present invention, the surface of the aluminum material to be surface-treated and the counter electrode are both flat, and the area of the conductive material connected to the aluminum material electrode in the electrolytic solution is as follows. The area where the corrosion-resistant oxide film is to be formed is 80 to 150%, and the distance between the conductive material and the aluminum material is 1 to 50 mm.

In the sixth aspect of the present invention, the conductive material connected to the aluminum material electrode in

claim

4 or 5 is made of a stainless steel material or a copper material.

According to a seventh aspect of the present invention, in the seventh aspect, in any one of the fourth to sixth aspects, a conductive material is disposed on one surface side of the aluminum material electrode so as to face this surface, and the other surface side of the aluminum material electrode By arranging the counter electrode so as to face this surface, a corrosion-resistant oxide film is formed on the one surface of the aluminum electrode, and a porous oxide film is formed on the other surface.

According to an eighth aspect of the present invention, in the eighth aspect, the counter electrode is disposed on the other surface side of the aluminum material electrode so as to face the surface, and the other surface and the counter electrode are arranged. The conductive material is disposed so as to face a part of the other surface of the aluminum material electrode, and the pair of the conductive material is opposed to another part complementary to the part of the other surface of the aluminum material electrode. By disposing the electrode, a corrosion-resistant oxide film was formed on the part of the other surface of the aluminum material electrode, and a porous oxide film was formed on the other part of the aluminum material electrode.

According to the present invention, a surface treatment is characterized in that a corrosion-resistant oxide film is formed on a part of the surface, and a porous oxide film having adhesion is formed in a portion where the corrosion-resistant oxide film is not formed. An aluminum material and a method for manufacturing the same are provided.

It is a partial cross section schematic diagram of the surface treatment aluminum material concerning the present invention. It is a cross-sectional schematic diagram of the other site | part of the surface treatment aluminum material which concerns on this invention. It is a front view which shows one embodiment of the electrolytic device of the aluminum material which concerns on this invention. It is a front view which shows the other embodiment of the electrolytic device of the aluminum material which concerns on this invention.

Hereinafter, details of the present invention will be described in order.
As shown in FIG. 1, a corrosion-resistant oxide film 3 is formed on a part of the surface of the surface-treated aluminum material 1 according to the present invention. Moreover, as shown in FIG. 2, the porous oxide film 4 is formed in the site | part of the surface of the aluminum material 2 in which the corrosion-resistant oxide film 3 is not formed.

A. About aluminum material As an aluminum material used for this invention, pure aluminum or an aluminum alloy is used. There is no restriction | limiting in particular in the component of an aluminum alloy, Various alloys including the alloy prescribed | regulated to JIS can be used. Although it does not restrict | limit especially as a shape, Since a processing film can be formed stably, a flat thing is used suitably.

B. 1. Corrosion-resistant oxide film structure on aluminum material surface As shown in FIG. 1, an amorphous corrosion-resistant oxide film having a thickness of 10 to 100 nm, preferably 20 to 80 nm, is formed on a part of the surface of the aluminum material 2 used in the present invention. 3 is formed. This corrosion-resistant oxide film 3 is a film having a single layer structure. In the case of a multi-layer structure that is not a single-layer structure, crevice corrosion occurs between the surface layer and the intermediate layer, so that sufficient corrosion resistance is not exhibited. Further, the corrosion-resistant oxide film 3 can be formed on the entire surface of the aluminum material 2. When the thickness of the corrosion resistant oxide film 3 is less than 10 nm, sufficient corrosion resistance cannot be obtained. On the other hand, when the thickness exceeds 100 nm, it is difficult to control the thickness of the corrosion-resistant oxide film, and processing unevenness occurs.

The film quality of the corrosion-resistant oxide film 3 is analyzed by FT-IR (Fourier transform infrared spectrophotometer), and the peak absorption wave number b (cm ⁻¹ ) of the infrared absorption spectrum and the baseline at the peak absorption wave number Characterized by the peak absorption from (a%). Here, the peak absorption wave number b (cm ⁻¹ ) refers to the peak absorption wave number resulting from the strongest stretching vibration of Al—O. The peak absorption wave number b (cm ⁻¹ ) usually appears in the range of 720 ≦ b ≦ 995.

In the corrosion-resistant oxide film used in the present invention, the peak absorption rate a (%) when analyzed by FT-IR is defined as 1 ≦ a ≦ 95, preferably 2 ≦ a ≦ 75. If this peak absorption rate is less than 1%, the thickness of the corrosion-resistant oxide film is less than 10 nm, resulting in insufficient corrosion resistance. When the peak absorption rate exceeds 95%, the thickness of the corrosion-resistant oxide film exceeds 100 nm, and it becomes difficult to control the thickness of the corrosion-resistant oxide film, and processing unevenness is likely to occur. Furthermore, in the present invention, the peak absorption rate a (%) and the peak absorption wave number b (cm ⁻¹ ) satisfy the relationship of b ≧ 3a + 710, preferably b ≧ 3a + 720. When this relationship is not satisfied, the corrosion resistance is deteriorated because the film shape of the corrosion-resistant oxide film becomes a porous shape.

C. 2. Porous oxide film structure on aluminum material surface As shown in FIG. 2, a porous oxide film 4 is formed on the surface of the aluminum material where the corrosion-resistant oxide film is not formed. The porous oxide film 4 includes a barrier-type aluminum oxide film layer 41 on the base side of the aluminum material 2 and a porous aluminum oxide film layer 42 on the surface layer side.

C-1. Porous Aluminum Oxide Film Layer The thickness of the porous aluminum oxide film layer 42 is 20 to 500 nm. If the thickness is less than 20 nm, the thickness is not sufficient, so that the formation of a small pore structure, which will be described later, is likely to be insufficient, and the adhesive force and adhesion force are reduced. On the other hand, when the thickness exceeds 500 nm, the porous aluminum oxide film layer itself tends to cohesively break down, and the adhesive force and adhesion force are reduced. The thickness of the porous aluminum oxide film layer 42 is preferably 30 to 400 nm.

Moreover, the porous aluminum oxide film layer 42 includes small holes 420 that extend from the surface in the depth direction. The diameter of the small holes 420 is 5 to 30 nm, preferably 10 to 20 nm. This small hole increases the contact area between the resin layer, the adhesive, and the like and the aluminum oxide film, and exhibits the effect of increasing the adhesive force and the adhesive force. If the diameter of the small hole is less than 5 nm, the contact area is insufficient, and sufficient adhesive force and adhesion force cannot be obtained. On the other hand, if the diameter of the small holes exceeds 30 nm, the entire porous aluminum oxide film layer becomes brittle and causes cohesive failure, resulting in a decrease in adhesion and adhesion.

The ratio of the total hole area of the small holes to the surface area of the porous aluminum oxide film layer is not particularly limited. The ratio of the total hole area of the small holes to the apparent surface area of the porous aluminum oxide film layer (the area represented by multiplication of the length and width without considering minute irregularities on the surface) is 25 to 75%. preferable. If it is less than 25%, the contact area may be insufficient and sufficient adhesive force or adhesion may not be obtained. On the other hand, if it exceeds 75%, the porous aluminum oxide film layer as a whole becomes brittle, causing cohesive failure and reducing the adhesive strength and adhesion.

C-2. Barrier type aluminum oxide film layer The barrier type aluminum oxide film layer 41 is a dense oxide film having a thickness of 3 to 30 nm. If the thickness is less than 3 nm, sufficient bonding force cannot be imparted to the bonding between the porous aluminum oxide film layer 4 and the aluminum substrate 2 as an intervening layer. It becomes insufficient. On the other hand, if the thickness exceeds 30 nm, the barrier type aluminum oxide film layer 3 tends to cohesively break due to its denseness, and on the contrary, the adhesive strength and the adhesive strength are lowered. The thickness of the barrier type aluminum oxide film layer 41 is preferably 5 to 25 nm.

C-3. Fluctuation width of the total thickness of the porous oxide film The thickness of the entire porous oxide film 4, that is, the porous aluminum oxide film layer 42 described in C-1 and the barrier type aluminum oxide film layer 41 described in C-2 As for the total thickness, the fluctuation range must be within ± 50%, preferably within ± 20%, regardless of where the porous oxide film 4 is formed. That is, the arithmetic average value of the total thickness of the porous oxide film measured at any plurality of locations on the aluminum material surface (preferably 10 locations or more and preferably 10 or more measurement points in each location) is T In the case of (nm), the total thickness of the porous oxide film in all of the plurality of measurement locations needs to be in the range of (0.5 × T) to (1.5 × T). If a location less than (0.5 × T) is present, the porous oxide film at that location becomes thinner than its surroundings. Then, in this thin area, a gap is likely to be generated between the porous oxide film and the adhesive to be adhered or the resin layer to be adhered, and the sufficient contact area cannot be secured and the adhesion and adhesion are reduced. To do.

On the other hand, if a location exceeding (1.5 × T) exists, the porous oxide film at that location becomes thicker than the surrounding area. Then, in this thick portion, stress from a resin layer or the like that should be in close contact concentrates to induce cohesive failure in the porous oxide film, resulting in a decrease in adhesive strength and close contact strength.

In addition, since the optical characteristics are different in the portion where the total thickness of the porous oxide film as described above is thin or thick, it may be visible as a change in color tone such as brown or cloudy color.

D. About the manufacturing method of an aluminum material As one method for manufacturing the surface treatment aluminum material which provided the corrosion-resistant oxide film and porous oxide film which satisfy | filled the above conditions on the surface, the electrode of the surface-treated aluminum material, A conductive material connected to the aluminum material and installed near the surface of the aluminum material, and an electrode made of a material described later as a counter electrode, a liquid temperature of 35 to 85 ° C. at a pH of 9 to 13, and a dissolved aluminum concentration The surface of the aluminum material facing the conductive material by AC electrolytic treatment using an alkaline aqueous solution of 5 ppm or more and 1000 ppm or less as the electrolytic solution under conditions of a frequency of 10 to 100 Hz, a current density of 4 to 50 A / dm ² and an electrolysis time of 5 to 60 seconds. Corrosion-resistant oxide film is formed on this part, and the part on the surface of the aluminum material facing the counter electrode is porous And a method in which reduction film is formed. In addition, only the corrosion-resistant oxide film can be formed on the surface by making the entire surface of the aluminum material face the conductive material.

The surface-treated aluminum material according to the present invention performs an alternating current electrolytic treatment using an aluminum material electrode to be surface treated, a conductive material connected to the aluminum material electrode, and a counter electrode. The conductive material connected to the electrode of the aluminum material to be surface-treated is arranged in the electrolytic solution in the vicinity of the surface portion of the aluminum material on which the corrosion-resistant oxide film is to be formed so as to face the surface portion. A porous oxide film is formed on the surface portion of the aluminum material that is not opposed to the conductive material. In the electrolytic solution, the area of the conductive material facing the aluminum material is 80 to 150%, preferably 90 to 130%, of the area of the aluminum material on which the corrosion-resistant oxide film is to be formed. The distance between the conductive material facing the aluminum material is 1 to 50 mm. If the area of the conductive material is less than 80% of the area of the aluminum material for which the corrosion-resistant oxide film is to be formed, a porous oxide film may be formed in a portion where the corrosion-resistant oxide film is to be formed. In some cases, the corrosion-resistant oxide film may be formed on the portion where the porous oxide film is to be formed. When the distance between the conductive material facing the aluminum material is less than 1 mm, convection of the electrolytic solution hardly occurs between the conductive material and the facing aluminum material, and uneven treatment of the corrosion-resistant oxide film is likely to occur. On the other hand, if the distance exceeds 50 mm, the distance between the conductive material and the facing aluminum material is too wide, so that a porous oxide film is formed on the entire surface of the aluminum material.

The alkaline aqueous solution used as the electrolytic solution in the AC electrolytic treatment step is a phosphate such as sodium phosphate, potassium hydrogen phosphate, sodium pyrophosphate, potassium pyrophosphate and sodium metaphosphate; sodium hydroxide and potassium hydroxide. An alkali metal hydroxide such as sodium carbonate, a carbonate such as sodium carbonate, sodium hydrogen carbonate, or potassium carbonate; an ammonium hydroxide; or an aqueous solution of a mixture thereof can be used. Since it is necessary to keep the pH of the electrolytic solution in a specific range as will be described later, it is preferable to use an alkaline aqueous solution containing a phosphate-based substance that can be expected to have a buffer effect. The concentration of the alkali component contained in such an alkaline aqueous solution is appropriately adjusted so that the pH of the electrolytic solution becomes a desired value, but is usually 1 × 10 ⁻⁴ to 1 mol / liter, preferably 1 × 10 6. ^-3 to 0.8 mol / liter. In addition, you may add surfactant to these alkaline aqueous solution for the improvement of dirt removal capability.

The pH of the electrolytic solution needs to be 9 to 13, and preferably 9.5 to 12. When the pH is less than 9, the alkaline etching power of the electrolytic solution is insufficient, so that the porous oxide film becomes an amorphous film and the formation of the predetermined porous aluminum oxide film layer and the barrier type aluminum oxide film layer becomes incomplete. . On the other hand, if the pH is less than 9, it is difficult to control the thickness of the corrosion-resistant oxide film, and uneven processing tends to occur. On the other hand, when the pH exceeds 13, the alkaline etching force becomes excessive, and the oxide film layer is difficult to grow, and the formation of a desired porous oxide film is hindered.

The electrolytic solution temperature needs to be 35 to 85 ° C, preferably 40 to 70 ° C. When the electrolytic bath temperature is less than 35 ° C., the formation of the porous oxide film becomes incomplete because the alkaline etching power is insufficient. On the other hand, when the temperature exceeds 85 ° C., the alkali etching force becomes excessive, and thus the formation of the porous oxide film and the corrosion-resistant oxide film is hindered.

The concentration of dissolved aluminum contained in the electrolytic solution needs to be 5 ppm or more and 1000 ppm or less, and preferably 10 ppm or more and 500 ppm or less. When the dissolved aluminum concentration is less than 5 ppm, the formation reaction of the oxide film at the initial stage of the electrolytic reaction occurs abruptly, resulting in the formation of a locally thick porous oxide film and unevenness in the corrosion-resistant oxide film. . On the other hand, when the dissolved aluminum concentration exceeds 1000 ppm, the viscosity of the electrolytic solution is increased, and uniform convection near the surface of the aluminum material is prevented in the electrolysis process, and at the same time, the dissolved aluminum suppresses the formation of a porous oxide film. Act on. As a result, a locally thin porous oxide film is formed. When the concentration of dissolved aluminum deviates from the above range, the fluctuation width of the total thickness of the porous aluminum oxide film layer and the barrier type aluminum oxide film layer in the entire porous oxide film formed on the surface of the aluminum material is determined as follows. It becomes difficult to make it within ± 50% of the arithmetic average value of the total thickness. As a result, the resulting porous oxide film is deteriorated in adhesion and adhesion.

The frequency used is 10 to 100 Hz. If the frequency is less than 10 Hz, a direct current element increases as electrolysis, and as a result, the formation of the porous aluminum oxide film layer does not proceed and a dense structure is obtained. On the other hand, when the frequency exceeds 100 Hz, the reversal of the anode and the cathode is too fast, so that the formation of the entire oxide film becomes extremely slow, and it takes an extremely long time to obtain a predetermined thickness for both the porous oxide film and the corrosion-resistant oxide film. It will take. The frequency used is preferably 20 to 80 Hz.

The current density needs to be 4 to 50 A / dm ² . When the current density is less than 4 A / dm ² , only the barrier type aluminum oxide film layer is preferentially formed in the porous oxide film, so that the porous type aluminum oxide film layer cannot be obtained. On the other hand, if it exceeds 50 A / dm ² , the current becomes excessive, so that it is difficult to control the thickness of the porous oxide film and the corrosion-resistant oxide film, and processing unevenness is likely to occur. The current density is preferably 5 to 30 A / dm ² .

Electrolysis time should be 5-60 seconds. When the treatment time is less than 5 seconds, the porous oxide film is formed too rapidly, so that the porous aluminum oxide film layer is not sufficiently formed, resulting in an oxide film composed of amorphous aluminum oxide. On the other hand, if it exceeds 60 seconds, the oxide film is re-dissolved, so that the corrosion-resistant oxide film layer is not sufficiently formed, and the productivity is also lowered. The electrolysis time is preferably 10 to 50 seconds.

One electrode of the pair of electrodes used for the alternating current electrolytic treatment is an aluminum material to be surface-treated by electrolytic treatment. As the other counter electrode, for example, a known electrode such as a graphite, aluminum, or titanium electrode can be used. However, the electrode does not deteriorate with respect to the alkaline component or temperature of the electrolytic solution, and has excellent conductivity. Must be made of a material that does not cause an electrochemical reaction. From such points, a graphite electrode is preferably used as the counter electrode. This is because the graphite electrode is chemically stable, inexpensive and easily available, and due to the action of many pores existing in the graphite electrode, the electric lines of force diffuse moderately in the AC electrolysis process. This is because the porous oxide film and the corrosion-resistant oxide film tend to be more uniform.

The conductive material connected to the portion where the corrosion-resistant oxide film is formed on the aluminum material by the electrolytic treatment needs to have a higher electrode potential than the aluminum material. A conductive material having a higher electrode potential than the aluminum material is connected to the aluminum material, and is placed in the vicinity of the aluminum material to perform electrolysis, thereby causing the cathode reaction in the alternating current electrolysis to occur on the surface of the conductive material, and the anode reaction to the aluminum material and conductive It can occur on the surface of the material. Therefore, a corrosion-resistant oxide film is formed on the aluminum material surface by the anodic reaction. The conductive material having a higher electrode potential than the aluminum material is, for example, gold, platinum, copper, iron, stainless steel, nickel or the like. In the present invention, stainless steel or copper is preferably used. This is because it is excellent in corrosion resistance in an alkaline solution, inexpensive and easy to process.

In the present invention, both the aluminum material to be electrolytically treated and the counter electrode are flat, and the opposing aluminum material and the opposing surface of the counter electrode have substantially the same dimensions, and both electrodes are electrolyzed in a stationary state. It is preferable to perform the operation. As shown in FIG. 3, it is preferable to prepare the counter electrode 5 and install the surface of the aluminum material 2 to be surface-treated so as to face the counter electrode plate 5 so as to be parallel to the surface of the counter electrode 5. . In the figure, 7 is an AC power source, and 8 is an electrolytic solution.

The shape of the conductive material 6 connected to the flat plate-shaped aluminum material 2 to be subjected to electrolytic treatment does not have to be a flat plate shape, and may be a net shape or a multi-hole shape. As shown in FIG. 3, for example, a conductive material 6 is disposed on one surface (the left surface in the drawing) side of the surface-treated aluminum material 2 so as to face this surface, and the other surface of the aluminum material 2 is disposed. On the surface (the surface on the right side in the figure), the counter electrode 5 is disposed so as to face this surface, and alternating current electrolysis is performed, whereby a corrosion-resistant oxide film is formed on the one surface of the aluminum material 2, and the other A porous oxide film can be formed on the surface.

As shown in FIG. 4 instead of the case of FIG. 3, a conductive material 6 is provided between the other surface (the right surface in the drawing) of the aluminum material 2 to be surface-treated and the counter electrode 5 corresponding to this surface. It can also be arranged. In this case, a part (the upper half in the figure) of the other surface of the aluminum material 2 is opposed to the conductive material 6, and the other part (the lower half in the figure) of the other surface of the aluminum material 2 is The conductive material 6 is opposed to the counter electrode 5. By performing alternating current electrolysis in such an arrangement, a corrosion-resistant oxide film is formed on a part of the other surface of the aluminum material facing the conductive material 6, and the other of the aluminum materials facing the counter electrode 5 instead of the conductive material 6 is formed. A porous oxide film is formed on another part of the surface, and a corrosion-resistant oxide film and a porous oxide film can be formed on the same surface of the aluminum material 2. 4, a part of the other surface of the aluminum material 2 (the lower half in the drawing) is made to face the conductive material 6, and the other portion of the other surface of the aluminum material 2 (the upper half in the drawing). Is arranged so as to face the counter electrode 5 instead of the conductive material 6, thereby forming a corrosion-resistant oxide film on a part of the other surface and forming a porous oxide film on the other part of the other surface. May be.

Furthermore, the part facing the conductive material 6 as a part of the other surface of the aluminum material 2 can have any shape, size and position. And the site | part made to oppose the counter electrode 5 as another site | part of the other surface of the aluminum material 2 can be made into a part complementary to the said part in the other surface.

For observation of the structure and thickness of the porous oxide film and the corrosion-resistant oxide film in the present invention, cross-sectional observation using a transmission electron microscope (TEM) is preferably used. Specifically, the thickness of the porous oxide film and the corrosion-resistant oxide film, and the diameter of the small holes in the porous oxide film layer can be measured by processing into thin pieces with an ultramicrotome or the like and observing them with a TEM.

Hereinafter, preferred embodiments of the present invention will be described based on examples and comparative examples.

As an aluminum material to be electrolytically treated, a JIS 5052 flat plate having a length of 500 mm, a width of 500 mm, and a thickness of 1.0 mm was used. This aluminum plate was used as one electrode, and a graphite plate or a titanium plate having a length of 500 mm, a width of 550 mm, and a thickness of 2.0 mm was used as the counter electrode. In Examples 1 to 23 and Comparative Examples 1 to 13, as shown in FIG. 3, the counter electrode 5 and the aluminum material 2 were disposed so as to be parallel to each other. A conductive material 6 is disposed in the vicinity of the surface of the aluminum alloy plate 2 opposite to the counter electrode 5, and a corrosion-resistant oxide film is provided on the entire surface of the aluminum alloy plate 2 on the conductive material 6 side, and the entire surface of the counter electrode side is porous. An oxide film was formed. In Example 24, as shown in FIG. 4, a part (the upper half in the drawing) of the other surface (the right-hand surface in the drawing) of the aluminum material 2 is opposed to the conductive material, The other part of the other surface (the lower half in the figure) is disposed so as to face the counter electrode 5 instead of the conductive material 6, and a corrosion-resistant oxide film and a porous oxide film are formed on the same surface of the aluminum material 2. Formed.

In Examples 1 to 14, 18 to 21, and Comparative Examples 1 to 13, a SUS304 stainless steel plate having a length of 500 mm, a width of 500 mm, and a thickness of 0.5 mm was used as the conductive material. In Example 15, a copper plate having a length of 500 mm, a width of 500 mm, and a thickness of 0.5 mm was used. In Example 16, a SUS304 stainless steel wire mesh having a length of 500 mm × width of 500 mm, a line diameter of 0.5 mm, a space ratio of 64.5%, and 10 mesh was used. In Example 17, SUS304 stainless steel punching metal having a length of 500 mm × width of 500 mm, a hole diameter of 6 mm, and a distance between holes (pitch) of 8 mm was used. In Example 22, a SUS304 stainless steel plate having a length of 480 mm, a width of 480 mm, and a thickness of 0.5 mm was used. In Example 23, a SUS304 stainless steel plate having a length of 570 mm, a width of 570 mm, and a thickness of 0.5 mm was used. In Example 24, a SUS304 stainless steel plate having a length of 250 mm, a width of 500 mm, and a thickness of 0.5 mm was used. The distance between the conductive material and the aluminum alloy plate was 5 mm in Examples 1 to 17, 22 to 24, and Comparative Examples 1 to 13. In Example 18, it was 2 mm, in Example 19, 45 mm, in Example 20, 0.5 mm, and in Example 21, 55 mm. In addition, in the area ratio of the electrically conductive material with respect to the area of the aluminum material shown in Table 1, the area of the electrically conductive material was calculated | required from the length and width which disregarded the space part.

As the electrolytic solution, an alkaline aqueous solution mainly composed of sodium pyrophosphate having the pH, temperature, and dissolved aluminum concentration shown in Table 1 was used. The pH of the electrolytic solution was adjusted with a 0.1 mol / liter NaOH aqueous solution. The alkaline component concentration of the alkaline aqueous solution was 0.1 mol / liter. Furthermore, the test material of the surface treatment aluminum material which implemented the electrolysis process on the alternating current electrolysis process conditions shown in Table 1, formed the corrosion-resistant oxide film in one surface of the aluminum plate, and formed the porous oxide film in the other surface Was made.

[Measurement of thickness of corrosion-resistant oxide film]
The cross section of the corrosion-resistant oxide film was observed by TEM for the test material produced as described above. Specifically, the thickness of the corrosion-resistant oxide film was measured, and the structure of the corrosion-resistant oxide film (whether the film layer has a single layer structure) was observed. In order to measure the thickness of the corrosion-resistant oxide film and observe the structure of the corrosion-resistant oxide film, a slice sample for cross-sectional observation was prepared from the test material using an ultramicrotome. Next, in this thin sample, any 100 points in the observation field (1 μm × 1 μm) are selected, and the thickness of the corrosion-resistant oxide film is measured by TEM cross-sectional observation, and whether or not the corrosion-resistant oxide film has a single-layer structure. (The case of a single layer structure was marked with ◯, and the case of no single layer structure was marked with x). When the thickness of the corrosion-resistant oxide film is 10 to 100 nm and the corrosion-resistant oxide film has a single-layer structure, the evaluation is acceptable (◯), and the thickness of the corrosion-resistant oxide film is not in the range of 10 to 100 nm and The evaluation in at least one of the cases where the corrosion-resistant oxide film is not a single layer structure was determined to be rejected (x). The results are shown in Table 2.

[Measurement of film thickness of porous oxide film]
Also in the porous oxide film layer, cross-sectional observation was performed by TEM. Specifically, the thickness of the porous aluminum oxide film layer and the barrier type aluminum oxide film layer in the porous oxide film layer, and the diameter of the small holes of the porous oxide film layer were measured. In order to measure these, a slice sample for cross-sectional observation was prepared from the test material using an ultramicrotome. Next, in this thin piece sample, arbitrary 100 points in the observation field (1 μm × 1 μm) are selected, and the thickness of the porous aluminum oxide film layer and the barrier type aluminum oxide film layer in the porous oxide film layer is determined by TEM cross-sectional observation. The diameter of the small holes in the porous oxide film layer was measured at each point. The maximum value, the minimum value, and the arithmetic average value of the total thickness of 100 porous aluminum oxide film layers and barrier aluminum oxide film layers thus measured were determined. Further, it was also examined whether or not the fluctuation range of the total thickness of the porous aluminum oxide film layer and the barrier type aluminum oxide film layer was within ± 50% of the arithmetic average value. Specifically, when the arithmetic average value is T (nm), the total thickness including the maximum value and the minimum value is in the range of (0.5 × T) to (1.5 × T). A case where it was acceptable was determined to be acceptable (O), and a case where it was not in range was regarded as unacceptable (x). In Example 24, the surface on the side facing the counter electrode was used. The results are shown in Table 2.

[Evaluation of corrosion resistance of corrosion resistant oxide film]
Ten specimens were cut from each test piece to a length of 50 mm and a width of 50 mm. The corrosion resistance test was conducted by the CASS test described in the salt spray test method (JIS Z 2371). The obtained anodized product was taken out after 3 hours in the CASS test, and the corrosion area ratio was evaluated by measuring the corrosion area in the corrosion-resistant oxide film. Here, the corrosion area ratio (%) was [(corrosion area) / (total area of the corrosion-resistant oxide film)] × 100.
○: Corrosion area ratio is less than 10% Δ: Corrosion area ratio is 10% or more and less than 50% ×: Corrosion area ratio is 50% or more The results are shown in Table 3. The table shows the number of the above-mentioned ○, Δ, and × among the 10 test pieces, respectively, and the case where all were ○ was determined to be acceptable, and the other was determined to be unacceptable.

[Film quality evaluation of corrosion-resistant oxide film]
The peak absorption wave number b (cm ⁻¹ ) of the corrosion-resistant oxide film and the peak absorption rate a (%) at the peak absorption wave number b were measured by FT-IR. An FT-IR detector (detector) having a measurable wave number in a wide range (400 to 4000 cm ⁻¹ ) was used, and the sample area was 30 mm × 50 mm. The results are shown in Table 3. The table shows that the peak absorption rate a (%) and the peak absorption wave number b (cm ⁻¹ ) are 1 ≦ a ≦ 95, and the peak absorption rate a (%) and the peak absorption wave number b (cm ⁻¹ ). A case where the relationship satisfies b ≧ 3a + 710 was determined to be acceptable (◯), and a case where the relationship was not within the range was determined to be unacceptable (×).

[Adhesive adhesion evaluation of porous oxide film]
Two samples cut from the test material to a length of 50 mm and a width of 25 mm were prepared. These two test materials are bonded to each other with a bonding width of 10 mm along the entire width direction, and the formation surfaces of the porous oxide film are overlapped, and a commercially available two-component epoxy adhesive (main component = modified epoxy resin, curing agent = modified) A superposed portion was adhered by polyimide, weight mixing ratio = main agent 100 / curing agent 100) to prepare a shear test piece. The lengthwise ends of the two specimens are pulled in the opposite direction along the length direction at a speed of 10 mm / min with a tensile tester, and the adhesive is changed depending on the load (converted to shear stress) and the peeled state. The adhesion was evaluated according to the following criteria. In addition, the shear test piece produced 10 sets of test pieces, and evaluated each. In Example 24, the surface on the side facing the counter electrode was used.
○: The shear stress is 20 N / mm ² or more and the adhesive layer itself is agglomerated and broken Δ: The shear stress is 20 N / mm ² or more, but the adhesive layer and the test material are separated at the interface × : Shear stress is less than 20 N / mm ² and the state where the adhesive layer and the specimen were peeled from each other The results are shown in Table 3. The table shows the number of pairs of the above-mentioned ○, Δ, and × of 10 sets of test pieces, respectively.

[Evaluation of adhesion of porous oxide film]
“V Freon # 2000” manufactured by Dainippon Paint Co., Ltd. was applied to the surface of the above test material on the porous oxide film side, dried (160 ° C., 20 minutes), and a resin coating having a thickness of 30 μm. An adhesion test piece having a shape was prepared. Using a cutter knife, a 1 mm square grid cut was made in the resin coating film of this adhesion test piece by a method according to JIS-K5600-5-6. Next, the test piece was subjected to a retort immersion treatment at 125 ° C. for 30 minutes, and then immediately removed from the treatment liquid to wipe off moisture. The test piece was subjected to a peel test using a transparent pressure-sensitive adhesive tape. The adhesion was evaluated according to the following criteria by the coating film residual ratio. In addition, the adhesive test piece produced 10 test pieces from the same test material, and evaluated each. In Example 24, the surface on the side facing the counter electrode was used.
○: The film remaining rate is 100%. Δ: The film remaining rate is 75% or more and less than 100%. X: The film remaining rate is less than 75%. The table shows the number of the above-mentioned ○, Δ, and × among the 10 test pieces, respectively, and the case where all were ○ was determined to be acceptable, and the other was determined to be unacceptable.

[Comprehensive evaluation]
Corrosion resistance evaluation and film quality evaluation of the corrosion resistant oxide film, and adhesive evaluation and coating film adhesion evaluation of the porous oxide film were all passed, and the overall evaluation was passed, and at least one of these evaluations An overall evaluation of one that failed was rejected.

As shown in Tables 2 and 3, in Examples 1 to 24, in order to satisfy the requirements of the present invention, the corrosion resistance and film quality of the corrosion-resistant oxide film are good, and the adhesiveness and coating adhesion of the porous oxide film The properties were good and the overall evaluation was acceptable. On the other hand, since Comparative Examples 1 to 13 did not satisfy the requirements of the present invention, at least one of the above evaluations failed, and the overall evaluation failed.

Specifically, in Comparative Example 1, the pH of the electrolytic solution in AC electrolysis was too low, so that the alkaline etching power was insufficient. Therefore, the diameter of the small holes in the porous aluminum oxide film layer was insufficient, the thickness of the barrier type aluminum oxide film layer was increased, and the fluctuation range of the porous oxide film thickness was increased. As a result, the adhesive adhesion and coating film adhesion of the porous oxide film were rejected, and the overall evaluation was rejected.

In Comparative Example 2, alkaline etching occurred excessively because the pH of the electrolytic solution in AC electrolysis was too high. For this reason, the thickness of the corrosion-resistant oxide film is insufficient, the thickness of the porous aluminum oxide film layer is insufficient, the diameter of the small holes is increased, and the thickness of the barrier aluminum oxide film layer is insufficient. As a result, the corrosion resistance of the corrosion resistant oxide film was rejected, and the adhesive adhesion and coating film adhesion of the porous oxide film were rejected, resulting in a failure of the overall evaluation.

In Comparative Example 3, the alkaline etching power was insufficient because the temperature of the electrolytic solution in AC electrolysis was too low. Therefore, the thickness of the barrier type aluminum oxide film layer was increased. Moreover, the diameter of the small hole of the porous aluminum oxide film layer was reduced. As a result, the adhesive adhesion and coating film adhesion of the porous oxide film were rejected, and the overall evaluation was rejected.

In Comparative Example 4, alkaline etching occurred excessively because the temperature of the electrolytic solution in AC electrolysis was too high. Therefore, the thickness of the corrosion-resistant oxide film and the thickness of the porous aluminum oxide film layer and the barrier type aluminum oxide film layer are insufficient. As a result, the corrosion resistance and film quality of the corrosion-resistant oxide film were rejected, and the adhesive adhesion and coating film adhesion of the porous oxide film were rejected, and the overall evaluation was rejected.

In Comparative Example 5, no dissolved aluminum was present in the electrolytic solution for AC electrolysis. Therefore, the formation reaction of the porous oxide film at the initial stage of the electrolytic reaction occurred rapidly, and the fluctuation range of the thickness of the porous oxide film became large. Moreover, the formation of the corrosion-resistant oxide film became non-uniform and the thickness was insufficient. As a result, the corrosion resistance and film quality of the corrosion-resistant oxide film were rejected, and the adhesive adhesion and coating film adhesion of the porous oxide film were rejected, and the overall evaluation was rejected.

In Comparative Example 6, a large amount of dissolved aluminum was present in the electrolytic solution of AC electrolysis. Therefore, the formation of the barrier type aluminum oxide film layer became non-uniform, and a locally thick part was formed, and the diameter of the small hole of the porous type aluminum oxide film layer was reduced. Furthermore, the fluctuation range of the porous oxide film thickness was increased. As a result, the adhesive adhesion and coating film adhesion of the porous oxide film were rejected, and the overall evaluation was rejected.

In Comparative Example 7, the DC component of the current became stronger because the frequency in AC electrolysis was too low. Therefore, the formation of the porous aluminum oxide film layer was suppressed and the thickness was insufficient. As a result, the adhesive adhesion and coating film adhesion of the porous oxide film were rejected, and the overall evaluation was rejected.

In Comparative Example 8, since the frequency in AC electrolysis was too high, the formation of the corrosion-resistant oxide film and the porous aluminum oxide film layer was suppressed, and the respective thicknesses were insufficient. As a result, the corrosion resistance and film quality of the corrosion-resistant oxide film were rejected, and the adhesive adhesion and coating film adhesion of the porous oxide film were rejected, and the overall evaluation was rejected.

In Comparative Example 9, since the current density in AC electrolysis was too low, the formation of the corrosion-resistant oxide film and the porous aluminum oxide film layer was suppressed, and the respective thicknesses were insufficient. As a result, the corrosion resistance and film quality of the corrosion-resistant oxide film were rejected, and the adhesive adhesion and coating film adhesion of the porous oxide film were rejected, and the overall evaluation was rejected.

In Comparative Example 10, the formation of the porous oxide film and the corrosion-resistant oxide film became non-uniform because the current density in AC electrolysis was too high. For this reason, the thickness of the corrosion-resistant oxide film and the thicknesses of the porous aluminum oxide film layer and the barrier type aluminum oxide film layer are increased. Moreover, the fluctuation range of the porous oxide film thickness was increased. As a result, the corrosion resistance and film quality of the corrosion-resistant oxide film were rejected, and the adhesive adhesion and coating film adhesion of the porous oxide film were rejected, and the overall evaluation was rejected.

In Comparative Example 11, since the electrolysis time in AC electrolysis was too short, the thickness of the corrosion-resistant oxide film and the thickness of the porous aluminum oxide film layer were insufficient. Moreover, the fluctuation range of the porous oxide film thickness was increased. As a result, the corrosion resistance and film quality of the corrosion-resistant oxide film were rejected, and the adhesive adhesion and coating film adhesion of the porous oxide film were rejected, and the overall evaluation was rejected.

In Comparative Example 12, the formation of the porous oxide film progressed too much because the electrolysis time in AC electrolysis was too long. Therefore, the thickness of the porous aluminum oxide film layer and the barrier type aluminum oxide film layer was increased. As a result, the adhesive adhesion and coating film adhesion of the porous oxide film were rejected, and the overall evaluation was rejected.

In Comparative Example 13, the dissolved aluminum was less than 5 ppm in the electrolytic solution of AC electrolysis. Therefore, the formation reaction of the porous oxide film at the initial stage of the electrolytic reaction occurred rapidly, and the fluctuation range of the thickness of the porous oxide film became large. Moreover, the formation of the corrosion-resistant oxide film became non-uniform and the thickness was insufficient. As a result, the corrosion resistance of the corrosion resistant oxide film was rejected, and the adhesive adhesion and coating film adhesion of the porous oxide film were rejected, resulting in a failure of the overall evaluation.

According to the present invention, it is possible to obtain a surface-treated aluminum material in which a part of the surface of the aluminum material is excellent in corrosion resistance and the other part of the surface of the aluminum material is excellent in adhesion and adhesion. Thus, the surface-treated aluminum material according to the present invention is suitably used for an aluminum-resin bonding member, a printed wiring board, and the like that require adhesion and adhesion only to a part of the aluminum material.

DESCRIPTION OF SYMBOLS 1 ... Surface treatment aluminum material 2 ... Aluminum material 3 ... Corrosion-resistant oxide film 4 ... Porous oxide film 41 ... Barrier type aluminum oxide film layer 42 ... Porous type aluminum oxide film layer 420 ... Small hole 5 ... Counter electrode 6 ... Conductive material 7 ... AC power supply 8 ... Electrolytic solution

Claims

Including an aluminum material, a corrosion-resistant oxide film having a single-layer structure formed on a part of the surface thereof, and a porous oxide film formed on a portion where the corrosion-resistant oxide film on the surface of the aluminum material is not formed,
The corrosion-resistant oxide film has a thickness of 10 to 100 nm. When the peak absorption wave number by FT-IR analysis is b (cm −1 ) and the peak absorption rate at the peak absorption wave number b is a (%). 1 ≦ a ≦ 95 and b ≧ 3a + 710 are satisfied,
The porous oxide film comprises a porous aluminum oxide film layer having a thickness of 20 to 500 nm formed on the surface side and a barrier type aluminum oxide film layer having a thickness of 3 to 30 nm formed on the substrate side. Small pores having a diameter of 5 to 30 nm are formed in the aluminum oxide film layer, and the total of the porous aluminum oxide film layer and the barrier type aluminum oxide film layer in the entire porous oxide film formed on the surface of the aluminum material. A surface-treated aluminum material characterized in that the variation width of the thickness is within ± 50% of the arithmetic average value of the total thickness.
2. The surface-treated aluminum material according to claim 1, wherein the peak absorption wave number b (cm −1 ) is a peak wave number due to the strongest stretching vibration of Al—O and appears in a range of 720 ≦ b ≦ 995.
The surface-treated aluminum material according to claim 1 or 2, wherein the ratio of the total pore area of the small pores to the apparent surface area of the porous aluminum oxide film layer is 25 to 75%.
Using an aluminum material electrode to be surface-treated, a counter electrode, and a conductive material connected to the aluminum material electrode, the pH is 9 to 13, the liquid temperature is 35 to 85 ° C., and the dissolved aluminum concentration is 5 ppm to 1000 ppm. The following alkaline aqueous solution is used as the electrolytic solution, and AC electrolytic treatment is performed under the conditions of a frequency of 10 to 100 Hz, a current density of 4 to 50 A / dm 2, and an electrolysis time of 5 to 60 seconds. A method for producing a surface-treated aluminum material, comprising forming a corrosion-resistant oxide film and simultaneously forming a corrosion-resistant oxide film on the surface of the aluminum material facing the conductive material connected to the aluminum material electrode.
The surface-treated aluminum material electrode and the counter electrode are both flat, and the area of the conductive material connected to the aluminum material electrode in the electrolytic solution is 80 to 150 of the area where the corrosion-resistant oxide film is to be formed. The method for producing a surface-treated aluminum material according to claim 4, wherein the distance between the conductive material and the aluminum material is 1 to 50 mm.
The method for producing a surface-treated aluminum material according to claim 4 or 5, wherein the conductive material connected to the aluminum material electrode is made of a stainless steel material or a copper material.
An aluminum material electrode is formed by disposing a conductive material on one surface side of the aluminum material electrode so as to face this surface and disposing a counter electrode on the other surface side of the aluminum material electrode so as to face this surface. The method for producing a surface-treated aluminum material according to any one of claims 4 to 6, wherein a corrosion-resistant oxide film is formed on the one surface and a porous oxide film is formed on the other surface.
A counter electrode is disposed on the other surface side of the aluminum material electrode so as to face this surface, and between the other surface and the counter electrode, so as to face a part of the other surface of the aluminum material electrode. A conductive material is disposed, and the counter electrode is disposed so as to face the other part complementary to the part of the other surface of the aluminum material electrode. The method for producing a surface-treated aluminum material according to any one of claims 4 to 6, wherein a corrosion-resistant oxide film is formed, and a porous oxide film is formed on the other part of the aluminum material electrode.