WO2017195808A1

WO2017195808A1 - Aluminum alloy material, aluminum alloy material provided with adhesive resin layer, joined body, and production method for aluminum alloy material

Info

Publication number: WO2017195808A1
Application number: PCT/JP2017/017638
Authority: WO
Inventors: 佑輔高橋; 悟高田
Original assignee: 株式会社神戸製鋼所
Priority date: 2016-05-10
Filing date: 2017-05-10
Publication date: 2017-11-16

Abstract

The present invention relates to an aluminum alloy material that comprises: an aluminum alloy base material; and a coating film that is formed on at least one portion of the surface of the aluminum alloy base material and that comprises an oxide of aluminum that includes silicon. Over a pre-and-post-coating difference spectrum obtained by Fourier-transform infrared spectroscopy using parallel polarized light that is incident at an angle of 75°, the coating film has an absorption peak top in the wavenumber domain of 1550-1650 cm^-1, and the absorbance of the coating film at said peak top is 0.001 or higher. The Si content of the coating film is at least 20 at% but less than 80 at%, the Mg content of the coating film is at least 0.1 at% but less than 30 at%, and the Cu content of the coating film is restricted to less than 0.6 at%.

Description

Aluminum alloy material, aluminum alloy material with adhesive resin layer, joined body, and method for producing aluminum alloy material

The present invention relates to an aluminum alloy material, an aluminum alloy material with an adhesive resin layer, a joined body using an aluminum alloy material or an aluminum alloy material with an adhesive resin layer, and a method for producing the aluminum alloy material.

From the viewpoint of reducing the weight of components used in transportation equipment such as automobiles, ships, and aircraft, development of technologies for joining different materials such as carbon fiber, aluminum alloy, and steel materials with different strengths, materials, and masses has attracted attention. Yes. In particular, adhesive resins (resin adhesives) have been actively researched in recent years because they do not corrode materials due to electrolytic corrosion and can bond various materials without corroding them. However, in a high humidity environment, moisture enters the interface between the metal and the adhesive resin, causing corrosion / deterioration of the metal surface and peeling easily at the interface between the metal and the adhesive resin, resulting in a significant decrease in adhesive strength. . For this reason, pretreatment that protects the interface between the metal and the adhesive resin from corrosion and does not reduce the adhesive strength even in a wet environment is an important factor that affects the adhesive durability.

Here, as a pretreatment for bonding, a surface treatment for improving the corrosion resistance and paint adhesion of a metal surface is known from the viewpoint of corrosion prevention.

For example, Patent Document 1 discloses that a solution containing a silicate ester, an aluminum inorganic salt, and polyethylene glycol and further containing a silane coupling agent is applied onto a galvanized steel sheet and dried to form a film. Thus, a technique for improving paint adhesion and white rust resistance is described.

Patent Document 2 discloses a technique for improving paint adhesion by treating the surface of a metal material such as steel or aluminum alloy with an aqueous solution containing water glass such as sodium water glass and silane such as aminosilane. Are listed.

Patent Document 3 discloses an adhesive formed on a metal such as aluminum by treating it with an aqueous composition containing a tetraalkyl silicate such as tetraethyl orthosilicate and a hydrated oxide sol such as silica sol. A method for improving the initial adhesion of the coating film and the long-term stability of the adhesion is described.

Japanese Patent No. 3289769 Japanese National Table 2014-502287 Japanese National Table No. 10-510307

However, the methods described in Patent Document 1 and Patent Document 2 are intended only for the purpose of preventing corrosion of metal surfaces and improving the adhesion of paints. Therefore, although the formed film is thick, the mechanical film itself has low mechanical strength and becomes brittle with respect to tension and stress, and high adhesive strength cannot be obtained.

Further, in the method described in Patent Document 3, since the adhesive strength is remarkably reduced by a long-term wet deterioration test, it cannot be said that the adhesion durability is sufficient.

In view of the problems as described above, the present invention provides an aluminum alloy material, an aluminum alloy material with an adhesive resin layer, and an aluminum alloy that have excellent adhesion durability, even when exposed to a high-temperature and humid environment. It is a main object to provide a joined body using a material or an aluminum alloy material with an adhesive resin layer, and a method for producing the aluminum alloy material.

As a result of intensive experiments to solve the above-mentioned problems, the present inventor found that the amount of Mg, Si and Cu are within a specific range on the surface of the aluminum substrate, and in the FT-IR spectrum. The present inventors have found that excellent adhesion durability can be obtained by forming a film made of an oxide of aluminum containing silicon having a specific peak.

That is, the present invention is an aluminum alloy material comprising an aluminum alloy base material and a film made of an oxide of aluminum containing silicon and formed on at least a part of the surface of the aluminum alloy base material. The difference spectrum before and after the coating treatment obtained by applying parallel polarized light with an incident angle of 75 ° by Fourier transform infrared spectroscopy has an absorption peak top in the wave number region of 1550 to 1650 cm ^−1. The absorbance at the top is 0.001 or more, and the coating contains Si at 20 atomic% or more and less than 80 atomic% and Mg at 0.1 atomic% or more and less than 30 atomic%, and Cu is 0.6 atom. An aluminum alloy material regulated to less than% is provided.

Here, the amounts of Si, Mg, and Cu in the film are values measured by a high-frequency glow discharge emission spectroscopy (GD-OES: Glow Discharge-Optical Emission Spectroscopy).

The aluminum alloy material of the present invention preferably has no absorption in the wave number region of 1440 to 1540 cm ⁻¹ in the difference spectrum.
The aluminum alloy material may be used by directly bonding an adhesive resin to the film.

The present invention also provides an aluminum alloy material with an adhesive resin layer in which an adhesive resin layer is directly formed on the film of the aluminum alloy material.

In the aluminum alloy material with an adhesive resin layer of the present invention, the adhesive resin layer preferably contains an organic-inorganic coupling agent.

In the aluminum alloy material with an adhesive resin layer of the present invention, the adhesive resin layer preferably contains an epoxy resin.

Furthermore, the present invention also provides a joined body obtained by joining the aluminum alloy material and another member via an adhesive resin.

Furthermore, the present invention also provides a joined body in which the above-described aluminum alloy material with an adhesive resin layer and another member are joined via an adhesive resin layer.

Furthermore, the present invention is a method for producing an aluminum alloy material comprising a film forming step of forming a film made of an oxide of aluminum containing silicon on at least a part of the surface of an aluminum alloy substrate, the film forming step Includes a heat treatment step for forming an oxide film on the surface of the aluminum alloy substrate, and an etching treatment step and a silicate treatment step after the heat treatment step, wherein the silicate treatment step is the etching treatment step. An aluminum alloy material, wherein the oxide film is treated with an aqueous solution containing 0.008% by mass or more and less than 0.5% by mass of silicate as the silicate treatment step after or simultaneously with the etching treatment step. A manufacturing method is also provided.

In the method for producing an aluminum alloy material of the present invention, it is preferable not to perform water washing after the treatment with the aqueous solution containing silicate.

In the method for producing an aluminum alloy material of the present invention, it is preferable to control the etching amount in the etching treatment step to less than 700 nm.

According to the present invention, it is possible to realize an aluminum alloy material that is hardly deteriorated in adhesive strength and is excellent in adhesion durability even when exposed to a high-temperature and humid environment.

FIG. 1 is a cross-sectional view schematically showing a configuration of an aluminum alloy material according to the first embodiment of the present invention. FIG. 2 is a flowchart showing a method for manufacturing the aluminum alloy material shown in FIG. FIG. 3 is a cross-sectional view schematically showing a configuration of an aluminum alloy material with an adhesive resin layer according to a modification of the first embodiment of the present invention. FIG. 4 is a flowchart showing a method of manufacturing the aluminum alloy material with an adhesive resin layer shown in FIG. FIG. 5 is a cross-sectional view schematically showing a configuration example of a joined body according to the second embodiment of the present invention. FIG. 6A is a cross-sectional view schematically showing another configuration example of the joined body according to the second embodiment of the present invention. FIG. 6B is a cross-sectional view schematically showing another configuration example of the joined body according to the second embodiment of the present invention. FIG. 7 is a cross-sectional view schematically showing another configuration example of the joined body according to the second embodiment of the present invention. FIG. 8A is a cross-sectional view schematically showing another configuration example of the joined body according to the second embodiment of the present invention. FIG. 8B is a cross-sectional view schematically showing another configuration example of the joined body according to the second embodiment of the present invention. FIG. 9A is a side view schematically showing a method for measuring the cohesive failure rate. FIG. 9B is a plan view schematically showing a method for measuring the cohesive failure rate.

Hereinafter, embodiments for carrying out the present invention will be described in detail. Note that the present invention is not limited to the embodiments described below.

(First embodiment)
First, the aluminum alloy material according to the first embodiment of the present invention will be described.
An aluminum alloy material according to the present embodiment is an aluminum alloy material including an aluminum alloy base material and a film made of an oxide of aluminum containing silicon and formed on at least a part of the surface of the aluminum alloy base material. The film has an absorption peak top in the wave number region of 1550 to 1650 cm ⁻¹ in the difference spectrum before and after the film treatment obtained by applying parallel polarized light having an incident angle of 75 ° by Fourier transform infrared spectroscopy. And the absorbance at the peak top is 0.001 or more, and the film contains Si at 20 atomic% or more and less than 80 atomic% and Mg at 0.1 atomic% or more and less than 30 atomic%, and Cu is contained. It is an aluminum alloy material regulated to less than 0.6 atomic%.

FIG. 1 is a cross-sectional view schematically showing the configuration of the aluminum alloy material of the present embodiment. As shown in FIG. 1, the aluminum alloy material 10 of the present embodiment has a film 2 formed on at least a part of the surface of an aluminum alloy base material 3 (hereinafter also referred to as a base material 3).

[Substrate 3]
The substrate 3 is made of an aluminum alloy. The type of aluminum alloy that forms the base material 3 is not particularly limited, and various non-heat-treatable or heat-treated aluminums that are defined in JIS or approximate to JIS, depending on the use of the processed member. It can be used by appropriately selecting from alloys. Here, as the non-heat treatment type aluminum alloy, there are pure aluminum (1000 series), Al—Mn series alloy (3000 series), Al—Si series alloy (4000 series), and Al—Mg series alloy (5000 series). Further, as the heat-treatable aluminum alloy, there are an Al—Cu—Mg alloy (2000 series), an Al—Mg—Si alloy (6000 series), and an Al—Zn—Mg alloy (7000 series).

For example, when the aluminum alloy material 10 of the present embodiment is used for an automobile member, the base material 3 preferably has a 0.2% proof stress of 100 MPa or more from the viewpoint of strength. Aluminum alloys that can form a base material that satisfies such characteristics include those containing relatively large amounts of magnesium, such as 2000 series, 5000 series, 6000 series, and 7000 series, and these alloys are necessary. Depending on the condition, it may be tempered. Among various aluminum alloys, it is preferable to use a 6000 series aluminum alloy because it has excellent age-hardening ability, has a relatively small amount of alloy elements, and is excellent in scrap recyclability and formability.

[Coating 2]
The coating 2 is a coating made of an oxide of aluminum containing silicon and formed on at least a part of the surface of the substrate 3. The film 2 absorbs in the wave number region of 1550 to 1650 cm ⁻¹ in the difference spectrum before and after the film treatment obtained by incident parallel polarized light with an incident angle of 75 ° by Fourier transform infrared spectroscopy (FT-IR). It has a peak top, the absorbance at the peak top is 0.001 or more, and the coating 2 contains 20 atomic% or more and less than 80 atomic% of Si and 0.1 atomic% or more and less than 30 atomic% of Mg. At the same time, Cu is restricted to less than 0.6 atomic%. The coating 2 is provided to increase the bonding strength and improve the adhesion durability. Hereinafter, the suitable range of each component amount contained in the film 2 will be described. In the aluminum alloy material shown in FIG. 1, the coating 2 is formed on the entire one surface of the substrate 3, but the present embodiment is not limited to this. For example, the film 2 may be formed on only a part of the surface of the substrate 3. Further, the coating 2 may be formed on both surfaces of the base material 3.

<FT-IR spectrum>
The formation mechanism of the film in the aluminum alloy material of this embodiment will be described below. First, when an aqueous solution of silicate is brought into contact with an oxide film on the surface of an aluminum substrate, a composite oxide of aluminosilicate having better corrosion resistance is generated. Next, the aqueous solution containing a trace amount of unreacted silicate remaining on the surface of the film reacts with carbon dioxide in the atmosphere during drying, and hydrogen carbonate and silicon dioxide are generated, so that the film becomes dense, It is thought that the corrosion resistance of the film is further improved.

Here, bicarbonate has an absorption wavelength in the wave number region of 1550 to 1650 cm ⁻¹ in the FT-IR analysis. The aluminum alloy material of the present embodiment has an absorption peak top in the wave number region of 1550 to 1650 cm ⁻¹ of the difference spectrum before and after the film treatment in the FT-IR analysis of the surface on which the film is formed. Absorbance at the top is 0.001 or more, hydrogen carbonate and silicon dioxide are sufficiently generated to form a dense film, and the film has excellent strength and corrosion resistance. The absorbance at the peak top of absorption in the wave number region of 1550 to 1650 cm ⁻¹ is preferably 0.005 or more, more preferably 0.007 or more.

On the other hand, if there is an excess of unreacted silicate on the film, the silicate remains on the surface of the film even after drying, and part of it reacts with carbon dioxide in the atmosphere to produce carbonate. The film thus formed is thick, and carbonate and silicate fine particles remain on the film surface. Such a film is brittle and has poor adhesion to the adhesive resin, so that the adhesion durability is significantly reduced.

The above mechanism is also supported by high-frequency glow discharge optical emission spectrometry (GD-OES analysis). That is, according to GD-OES analysis, an aluminum alloy material having an absorption wavelength in the wave number region of 1550 to 1650 cm ⁻¹ has a layer of an aluminosilicate composite oxide film containing silicon dioxide from the outermost surface to the base material. Observed. On the other hand, regarding the aluminum alloy material having absorption in the wave number region of 1440 to 1540 cm ⁻¹ , it is observed that the layer containing carbonate is concentrated on the outermost surface.

Here, the carbonate has an absorption wavelength in the wave number region of 1440 to 1540 cm ⁻¹ in the FT-IR analysis. From the above viewpoint, the aluminum alloy material of the present embodiment has no absorption in the wave number region of 1440 to 1540 cm ⁻¹ of the difference spectrum before and after the film treatment in the FT-IR analysis of the surface on which the film is formed. It is preferable. That is, the film of the aluminum alloy material of the present embodiment is preferably made of a complex oxide having no absorption in the wave number region of 1440 to 1540 cm ⁻¹ in the difference spectrum before and after the film processing by FT-IR analysis. In the present specification, “having no absorption in the wave number region of 1440 to 1540 cm ⁻¹ ” means that no absorbance is measured in the wave number region of 1440 to 1540 cm ⁻¹ .
The difference spectrum before and after the film treatment is the difference between the absorption spectrum of the surface of the aluminum alloy material on which the film is formed and the absorption spectrum of the aluminum alloy substrate on which the film is not formed. Is the difference.

<Mg content: 0.1 atomic% or more and less than 30 atomic%>
The aluminum alloy constituting the base material of the aluminum alloy material usually contains magnesium (Mg) as an alloy component, and an oxide film that is a composite oxide of aluminum and magnesium is formed on the surface of the base material 3. When formed, magnesium will be present in a concentrated state on the surface. For this reason, when an adhesive resin is formed on the oxide film, the surface magnesium becomes a weak boundary layer of the adhesive interface, and the initial bonding strength is lowered.

Also, in a high-temperature and humid environment where moisture, oxygen, etc. penetrate, it causes hydration of the interface with the adhesive resin and corrosion of the base material, thereby reducing the bonding strength of the aluminum alloy material. Specifically, when the Mg content in the film is 30 atomic% or more, the bonding strength of the aluminum alloy material tends to decrease. Therefore, in the aluminum alloy material 10 of the present embodiment, the Mg content in the coating 2 is restricted to less than 30 atomic%. Thereby, adhesion durability can be improved. The Mg content of the film 2 is preferably less than 25 atomic%, more preferably less than 20 atomic%, and still more preferably less than 10 atomic%, from the viewpoint of improving adhesion durability.

On the other hand, the lower limit of the Mg content of the film 2 is set to 0.1 atomic% or more from the viewpoint of economy. Here, the Mg content in the film 2 can be measured by high-frequency glow discharge optical emission spectrometry (GD-OES).

The method for adjusting the Mg content of the film 2 is not particularly limited. For example, an acid solution such as nitric acid, sulfuric acid and hydrofluoric acid, or an acidic solution such as mixed acid, or potassium hydroxide, sodium hydroxide, silicic acid. A method of performing a surface treatment with an alkaline solution containing a salt and carbonate can be applied. This method adjusts the Mg content of the film 2 by dissolving magnesium in an acid or alkali solution. By adjusting the treatment time, temperature, concentration of the surface treatment solution and pH, the film 2 The amount of Mg can be in the range described above. Even if Mg is contained to the extent of an impurity element, Mg may concentrate in the coating 2 when heat treatment is performed at high temperature, and adjustment by surface treatment with acid or alkali is possible. Is necessary as appropriate. It is also possible to adjust the surface treatment chemical solution by containing Mg ions.

<Si content: 20 atomic% or more and less than 80 atomic%>
Since silicon has the effect of improving the corrosion resistance of the coating 2 and stabilizing it in a wet environment, it is possible to suppress a decrease in bonding strength by containing silicon in the coating 2.

However, when the Si content in the film 2 is less than 20 atomic%, the above-described effect tends to be small, and when the Si content is 80 atomic% or more, the film becomes thick and brittle, and as a result There exists a tendency for adhesive strength to fall large. Further, the spot weldability and the uniformity of the chemical conversion treatment tend to decrease. Therefore, in the aluminum alloy material 10 of the present embodiment, the Si content in the coating 2 is set to 20 atom% or more and less than 80 atom%.

From the viewpoint of improving adhesion durability, the Si content in the film 2 is preferably 25 atomic% or more, and more preferably 30 atomic% or more. Further, from the viewpoint of preventing the decrease in adhesive strength and the uniformity of spot weldability and chemical conversion treatment, the Si content in the coating 2 is preferably less than 75 atomic%, and more preferably less than 70 atomic%. preferable.

The Si content in the film 2 is adjusted, for example, by performing a surface treatment with an acid or an alkali in the same manner as described as a method for adjusting the amount of Mg. Moreover, it adjusts with the conditions of the process by the aqueous solution containing silicates, such as sodium silicate and potassium silicate mentioned above.

<Cu content: less than 0.6 atomic%>
When excessive etching is performed on the base material 3 by a degreasing process, a pickling process, or the like when forming the film 2, the Cu contained in the base material 3 is concentrated on the surface, and the Cu content of the film 2 is increased. . When Cu is present on the surface of the film 2, the adhesion with the adhesive resin that is directly bonded onto the surface of the film 2 is reduced.

Therefore, in the aluminum alloy material of the present embodiment, the Cu content in the coating 2 is restricted to less than 0.6 atomic%. In addition, it is preferable that the amount of Cu in the film | membrane 2 is less than 0.5 atomic% from a viewpoint of an adhesive improvement with adhesive resin.

In order to control the Cu content in the film 2, it is necessary to adjust the etching amount by the pretreatment, but the etching method is not limited. For example, the same processing method as described in the numerical value limitation of Mg Can be applied. That is, for example, etching can be performed by treatment with an acid or alkali solution.

Here, the element concentration such as Mg amount, Si amount, and Cu amount in the film 2 can be measured by, for example, a high-frequency glow discharge emission spectroscopic analysis (GD-OES: Glow Discharge-Optical Emission Spectroscopy). In the present embodiment, each element except oxygen (O), nitrogen (N), and carbon (C), specifically aluminum (Al), magnesium (in the thickness direction of the base material 3 by GD-OES. Mg), sodium (Na), calcium (Ca), copper (Cu), iron (Fe), titanium (Ti) and other metal elements and silicon (Si) and other elements are measured. A value obtained by calculating the content of Cu, Al, etc. as a percentage is defined as the amount of each element.

<Film thickness>
The thickness of the film 2 is preferably 1 to 30 nm. When the film thickness of the film 2 is less than 1 nm, the ester in the press oil used when producing a joined body or an automobile member from the rust preventive oil or the aluminum alloy material 10 used when the base material 3 is produced. Adsorption of components is suppressed. For this reason, even if it does not provide the membrane | film | coat 2, the degreasing | defatting property, chemical conversion treatment property, and adhesion durability of the aluminum alloy material 10 are securable. However, in order to control the film thickness of the film 2 to be less than 1 nm, excessive acid cleaning or the like is required, so that productivity is inferior and practicality tends to be lowered. Moreover, excessive etching by alkali degreasing or acid causes the Cu contained in the base material 3 to be concentrated on the surface, and causes a decrease in adhesion durability.

On the other hand, when the film thickness of the film 2 exceeds 30 nm, the amount of the film becomes excessive, and irregularities are easily formed on the surface. When the surface of the coating 2 is uneven, for example, chemical conversion spots are likely to occur during the chemical conversion treatment performed before the coating process in automobile applications, leading to a decrease in chemical conversion. The film thickness of the film 2 is more preferably 2 nm or more and less than 20 nm from the viewpoints of chemical conversion and productivity.

[Production method]
Next, the manufacturing method of the aluminum alloy material of this embodiment is demonstrated. FIG. 2 is a flowchart showing a method for manufacturing the aluminum alloy material 10 of the present embodiment shown in FIG. As shown in FIG. 2, when manufacturing the aluminum alloy material 10 of this embodiment, base material production process S1 and film formation process S2 are performed. Hereinafter, each step will be described.

<Step S1: Base material production process>
The shape of the substrate is not particularly limited, and depending on the shape of a member produced using an aluminum alloy material, in addition to a plate shape, a cast material, a forged material, an extruded material (for example, a hollow bar shape), etc. Any shape that can be taken as In the base material manufacturing step S1, when a plate-shaped base material (substrate) is manufactured as an example, the substrate is manufactured by the following procedure, for example. First, an aluminum alloy having a predetermined composition is melted by continuous casting and cast to produce an ingot (melting casting process). Next, the produced ingot is subjected to homogenization heat treatment (homogenization heat treatment step). Thereafter, the ingot subjected to homogenization heat treatment is hot-rolled to produce a hot-rolled sheet (hot-rolling step). Then, the hot-rolled sheet is subjected to rough annealing or intermediate annealing at 300 to 580 ° C., and cold rolling with a final cold rolling rate of 5% or more is performed at least once, so that a cold-rolled sheet (substrate) having a predetermined thickness is obtained. (Cold rolling process).

In the cold rolling process, it is preferable to set the temperature of rough annealing or intermediate annealing to 300 ° C. or higher, and thereby the effect of improving formability is more exhibited. Moreover, it is preferable that the temperature of rough annealing or intermediate annealing shall be 580 degrees C or less, and this becomes easy to suppress the fall of the moldability by generation | occurrence | production of burning. On the other hand, the final cold rolling rate is preferably 5% or more, and thereby, the effect of improving the formability is more exhibited. In addition, the conditions of homogenization heat processing and hot rolling are not specifically limited, It can carry out on the conditions in the case of obtaining a hot rolled sheet normally. Further, intermediate annealing may not be performed.

<Step S2: Film formation process>
In the film forming process (step S2), a film is formed on at least a part (that is, part or all) of the surface of the base material manufactured in the base material manufacturing process in step S1. In the present embodiment, specifically, the film formation step (step S2) includes, for example, a heat treatment stage in which the base material 3 is heat-treated to form an oxide film, an etching treatment stage after the heat treatment stage, and a silica film. An acid treatment stage. Here, as a silicate treatment step, treatment is performed with an aqueous solution containing silicate. Thereby, the film is formed so that the Mg amount, Si amount, and Cu amount in the film are in a specific range and have a specific peak in the FT-IR spectrum.

As the heat treatment in the heat treatment stage, the base material 3 is heated to a temperature of 400 to 580 ° C., for example, to form an oxide film on the surface of the base material 3. Further, the heat treatment also has an effect of adjusting the strength of the aluminum alloy material 10. The heat treatment performed here is a solution treatment when the substrate 3 is formed of a heat-treatable aluminum alloy, and is annealed when the substrate 3 is formed of a non-heat-treatable aluminum alloy. It is heat processing in (final annealing).

This heat treatment is preferably rapid heating at a heating rate of 100 ° C./min or more from the viewpoint of improving the strength. Moreover, the strength of the aluminum alloy material 10 and the strength after heating (baking) of the aluminum alloy material 10 can be further increased by setting the heating temperature to 400 ° C. or higher and performing rapid heating. On the other hand, by setting the heating temperature to 580 ° C. or less and performing rapid heating, it is possible to suppress a decrease in formability due to the occurrence of burning. Furthermore, from the viewpoint of improving strength, the holding time in the heat treatment is preferably 3 to 30 seconds. When the substrate 3 is heated at a heating temperature of 400 to 580 ° C. in this way, an oxide film having a film thickness of 1 to 30 nm, for example, is formed on the surface of the substrate 3. In addition, you may perform alkali degreasing | defatting etc. as needed before heat processing.

In the etching treatment stage after the heat treatment, treatment with an acidic solution (pickling) and treatment with an alkaline solution (alkali washing, alkaline degreasing) are performed on part or all of the surface of the oxide film formed on the substrate 3. ) At least one of Although the chemical solution (acid detergent) used in the pickling is not particularly limited, for example, a solution containing one or more selected from the group selected from sulfuric acid, nitric acid and hydrofluoric acid can be used. The acid detergent may contain a surfactant in order to improve the degreasing property. The pickling conditions can be appropriately set in consideration of the alloy composition of the base material 3, the thickness of the oxide film, etc., and are not particularly limited. For example, the pH is 2 or less, the treatment temperature is 10 to 80 ° C., Conditions with a processing time of 1 to 120 seconds can be applied.

Also, the chemical solution used for alkali cleaning (alkali degreasing) is not particularly limited, and for example, a solution containing at least one selected from the group selected from sodium hydroxide and potassium hydroxide can be used. . Further, the conditions for the treatment with the alkaline solution can be appropriately set in consideration of the alloy composition of the substrate 3, the thickness of the oxide film, and the like, and are not particularly limited. For example, the pH is 10 or more, and the treatment temperature is 10 to 80. Conditions of ° C and a treatment time of 1 to 120 seconds can be applied.

In addition, when performing alkali cleaning, it is preferable to perform pickling after alkali cleaning. The reason for this is as follows. That is, with alkali cleaning, it is difficult to remove Mg on the substrate surface, and the amount of etching needs to be increased due to the presence of Mg on the substrate surface. However, increasing the etching amount causes the concentration of Cu, so it is necessary to remove Mg by pickling.

In addition, it is preferable to perform rinsing after washing with each chemical solution. The rinsing method is not particularly limited, and examples thereof include spraying and dipping. Examples of the cleaning liquid used for rinsing include industrial water, pure water, and ion exchange water.

It should be noted that excessive etching of an aluminum alloy containing copper causes copper concentration on the surface and causes deterioration of the adhesive resin in a high temperature and humid environment, which is a deteriorated environment. Accordingly, the processing conditions are adjusted so that the etching amount of the oxide film is preferably less than 700 nm, more preferably less than 500 nm.

Here, the etching amount in the etching treatment stage in the present specification is the dissolution amount of the oxide film or the base material including the oxide film, and the decrease in weight before and after the etching treatment is measured, and the thickness (film thickness) is measured. ). In addition, the conversion from the weight reduction amount to the film thickness is performed by calculating the aluminum thickness using the aluminum density of 2.7 g / cm ³ for convenience. In addition to the oxide film, when a part of the base material under the oxide film is also etched, the total etching amount of the oxide film and the base material is defined as the etching amount.

Also, as a silicate treatment step, a substrate having an oxide film is treated with an aqueous solution containing silicate (silicate aqueous solution). Here, the treatment with the silicate aqueous solution includes not only the application of the silicate aqueous solution but also the immersion in the silicate aqueous solution. When the treatment with the silicate aqueous solution is performed, hydrogen carbonate and silicon dioxide are generated, and the oxide film becomes a denser film 2, which improves the strength of the film itself and also improves the corrosion resistance. Note that the silicate treatment stage is performed as the final stage of film formation in the film formation process, and no pickling is performed after the silicate treatment. However, drying after treatment with an aqueous silicate solution is included in the silicate treatment step.

Here, when the pH of the aqueous solution is lower than 7, silicate precipitates, so that aluminum and silicon cannot react. Accordingly, the pH of the silicate aqueous solution needs to be 7 or more, preferably 8 or more, and more preferably 9 or more. Moreover, although the upper limit of pH of silicate aqueous solution is not specifically limited, From the viewpoint of the ease of handling and safety | security of a solution, it is 14 or less, for example, Preferably it is 13 or less. The pH of the silicate aqueous solution can be appropriately adjusted by adding a base such as sodium hydroxide, sodium carbonate, or ammonia.

It is preferable that the density | concentration of the silicate in the silicate aqueous solution apply | coated to an oxide film is 0.008 mass% or more and less than 0.5 mass%. When the concentration of the silicate in the silicate aqueous solution is 0.008% by mass or more, since the hydrogen carbonate and silicon dioxide are sufficiently generated by drying, the film becomes dense and the film has excellent strength and corrosion resistance. Can be formed. From the same viewpoint, the silicate concentration in the silicate aqueous solution is more preferably 0.02% by mass or more, and further preferably 0.06% by mass or more. On the other hand, if the silicate concentration in the silicate aqueous solution is excessively high, silicate remains on the surface of the film even after drying, and some of it may react with carbon dioxide in the atmosphere to produce carbonate. There is. In this case, the formed film becomes thick, and fine particles of carbonate or silicate remain on the surface of the film. As a result, the formed film is fragile and has poor adhesion to the adhesive resin, which may significantly reduce the adhesion durability.
Therefore, from the viewpoint of preventing this, the silicate concentration in the silicate aqueous solution is preferably less than 0.5% by mass, more preferably less than 0.3% by mass, and still more preferably 0%. Less than 2% by mass.

The type of silicate contained in the silicate aqueous solution is not particularly limited. For example, basic silicates include silicates of alkali metals such as lithium, sodium, and potassium, and ammonium silicates. Can be mentioned. Here, as a silicate, only 1 type may be used independently and may be used in combination of 2 or more type.
Examples of the lithium silicate include lithium silicate.
Examples of sodium silicate (mNa ₂ O · nSiO ₂ can be expressed as n / m in a molar ratio below) include, for example, crystalline sodium orthosilicate (n / m: about 0.5), meta Sodium silicate (n / m: about 1), layered crystal sodium silicate (n / m: in the range of about 2 to 3), amorphous sodium silicate, or liquid water glass (JIS No. 1, 2 and 3).
As potassium silicate, potassium silicate etc. are mentioned, for example.

Examples of the application method of the silicate aqueous solution include immersion treatment, spraying, roll coating, bar coating, electrostatic coating and the like.

Also, it is preferable not to perform rinsing after the oxide film is treated with the silicate aqueous solution. Washing with water (rinse) removes the unreacted silicate aqueous solution remaining on the surface of the film. As a result, hydrogen carbonate and silicon dioxide are not sufficiently formed even after drying, and a dense film cannot be obtained. There is a fear.

After the treatment with the silicate aqueous solution, the silicate aqueous solution is dried. The drying temperature is preferably 70 ° C. or higher, more preferably 80 ° C. or higher, and still more preferably 90 ° C. or higher. In addition, if the drying temperature is too high, the characteristics of the aluminum alloy are affected. Therefore, the drying temperature is preferably 220 ° C. or lower, more preferably 200 ° C. or lower, and further preferably 190 ° C. or lower. The drying time depends on the drying temperature, but is preferably 2 seconds or more, more preferably 5 seconds or more, and further preferably 10 seconds or more. Moreover, the said drying time becomes like this. Preferably it is 20 minutes or less, More preferably, it is 5 minutes or less, More preferably, it is 2 minutes or less.

The coating amount of the silicate aqueous solution is preferably adjusted so that the coating amount after drying is 1 mg / m ² or more and 30 mg / m ² or less from the viewpoint of obtaining a sufficient effect of improving the adhesion durability. More preferably, the coating amount after drying is adjusted to be 1.5 mg / m ² or more and 20 mg / m ² or less. If the coating amount of the silicate aqueous solution is too small, the amount of silicate is too small, and good adhesion durability may not be obtained. Moreover, when the application amount of the silicate aqueous solution becomes too large, the formed film becomes too thick, peeling occurs in the film, and the adhesion durability may be impaired.

In the above-described film forming step of Step S1, the silicate treatment stage is performed after the etching treatment stage, but these may be performed in a single process. Specifically, for example, the oxide film may be treated using a neutral or alkaline aqueous solution containing silicate.

<Other processes>
In the manufacturing method of the aluminum alloy material 10 of the present embodiment, other steps may be included between or before and after each step within a range that does not adversely affect each step described above. For example, a preliminary aging treatment step for performing a preliminary aging treatment may be provided after the film forming step S2. This preliminary aging treatment is preferably performed by heating at 40 to 120 ° C. within 72 hours at a low temperature of 8 to 36 hours. By performing pre-aging treatment under these conditions, it is possible to improve moldability and strength after baking. In addition, for example, a foreign matter removing step for removing foreign matter on the surface of the aluminum alloy material 10 or a defective product removing step for removing defective products generated in each step may be performed.

And, the manufactured aluminum alloy material 10 may be coated with press oil on the surface thereof before the fabrication of the joined body or before processing into a member for an automobile. As the press oil, one containing an ester component is mainly used. The method and conditions for applying the press oil to the aluminum alloy material 10 are not particularly limited, and methods and conditions for applying the normal press oil can be widely applied. For example, a press containing ethyl oleate as an ester component What is necessary is just to immerse the aluminum alloy material 10 in oil. The ester component is not limited to ethyl oleate, and various materials such as butyl stearate and sorbitan monostearate can be used.

As described above in detail, according to the manufacturing method of the aluminum alloy material of the present embodiment, high adhesion durability can be obtained without performing water washing after treatment with an aqueous silicate solution or treatment with a silane coupling agent. Since the applied film can be obtained, the entire process can be reduced, which is very useful from the viewpoint of production efficiency.

The aluminum alloy material of the present embodiment may be used by directly bonding an adhesive resin to the film. Here, as described above, press oil may be applied to the surface of the aluminum alloy material, but in this specification, an adhesive resin is bonded to the aluminum alloy material applied with the press oil. In addition, it is included that the adhesive resin is directly bonded to the aluminum alloy material film.

(Modification of the first embodiment)
Next, an aluminum alloy material with an adhesive resin layer according to a modification of the first embodiment of the present invention will be described. FIG. 3 is a cross-sectional view schematically showing a configuration of an aluminum alloy material with an adhesive resin layer according to this modification. In FIG. 3, the same components as those of the aluminum alloy material 10 shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted. As shown in FIG. 3, the adhesive resin layer 4 is directly formed on the aluminum alloy material 11 with the adhesive resin layer of the present modification so as to cover the film 2 on the aluminum alloy material of the first embodiment described above. .

[Adhesive resin layer 4]
The adhesive resin layer 4 is made of an adhesive resin or the like, and the aluminum alloy material 11 with the adhesive resin layer of the present modification is joined to another member via the adhesive resin layer 4. The other members include another aluminum alloy material in which a film is formed as in the case of the aluminum alloy material 11 with the adhesive resin layer, an aluminum alloy material in which no oxide film is formed, a resin molded body, and the like. .

The adhesive resin that constitutes the adhesive resin layer 4 is not particularly limited. When an aluminum alloy material such as an epoxy resin, a urethane resin, a nitrile resin, a nylon resin, or an acrylic resin is conventionally joined. The adhesive resin that has been used can be used. Of these, epoxy resins are preferable from the viewpoint of adhesive strength. Further, only one kind of adhesive resin may be used, or a plurality of adhesive resins may be used in combination.

The thickness of the adhesive resin layer 4 is not particularly limited, but is preferably 10 to 500 μm, and more preferably 50 to 400 μm. When the thickness of the adhesive resin layer 4 is less than 10 μm, the aluminum alloy material 11 with the adhesive resin layer and the aluminum alloy material not provided with another adhesive resin layer are joined via the adhesive resin layer 4. , High adhesion durability may not be obtained. On the other hand, when the thickness of the adhesive resin layer 4 exceeds 500 μm, the adhesive strength may be reduced.

The adhesive resin layer 4 (adhesive resin) may further contain an organic-inorganic coupling agent. The type of organic-inorganic coupling agent contained in the adhesive resin layer 4 (adhesive resin) is not particularly limited. For example, in addition to a silane coupling agent, a titanate coupling agent, an aluminate coupling agent, or a phosphate cup. A ring agent or the like can be used. Further, as the silane coupling agent, at least one functional group such as vinyl group, styryl group, acrylic group, methacryl group, epoxy group, amino group, ureido group, mercapto group, isocyanate group and the like having high reactivity with the adhesive resin is used. It is preferable to use the silane coupling agent having the above. Preferable specific examples of the functional group possessed by the silane coupling agent include, for example, an epoxy group, an amino group, and a ureido group. Here, as the organic-inorganic coupling agent, only one kind may be used alone, or two or more kinds may be used in combination.

[Production method]
Next, the manufacturing method of the aluminum alloy material 11 with the adhesive resin layer of this modification is demonstrated. FIG. 4 is a flowchart showing a method of manufacturing the aluminum alloy material 11 with an adhesive resin layer of the present modification shown in FIG. As shown in FIG. 4, when manufacturing the aluminum alloy material 11 with an adhesive resin layer of this modification, an adhesive resin layer forming step S3 is performed in addition to the steps S1 to S2 described above.

<Step S3: Adhesive resin layer forming step>
In the adhesive resin layer forming step S3, the adhesive resin layer 4 is formed so as to cover the film 2. The method for forming the adhesive resin layer 4 is not particularly limited. For example, when the adhesive resin is a solid, it is heated and pressure-bonded, or dissolved in a solvent to obtain a solution. Further, when the adhesive resin is in a liquid state, a method of spraying or coating the surface of the film 2 as it is can be mentioned.

Moreover, also in the aluminum alloy material 11 with the adhesive resin layer of this modification, the preliminary aging treatment is performed after the film forming step S2 and / or the adhesive resin layer forming step S3, as in the first embodiment. An aging treatment step may be provided.

In the aluminum alloy material with an adhesive resin layer of this modification, since the adhesive resin layer is provided in advance, the work such as applying the adhesive resin to the surface of the aluminum alloy material is omitted when producing a joined body or an automobile member. can do. The configuration and effects other than those described above in the aluminum alloy material with an adhesive resin layer of the present modification are the same as those in the first embodiment described above.

(Second Embodiment)
Next, the joined body according to the second embodiment of the present invention will be described. The joined body of this embodiment uses the aluminum alloy material of the first embodiment described above or an aluminum alloy material with an adhesive resin layer of a modification thereof. 5 to 8B are cross-sectional views schematically showing a configuration example of the joined body of this embodiment. 5 to 8B, the same components as those of the aluminum alloy material 10 and the aluminum alloy material 11 with the adhesive resin layer shown in FIGS. 1 and 3 are denoted by the same reference numerals, and detailed description thereof is omitted.

[Composition structure]
In the joined body of this embodiment, for example, like the joined body 20 shown in FIG. 5, the two aluminum alloy materials 10 shown in FIG. 1 are arranged so that the surfaces on which the coating 2 is formed face each other. Further, it can be configured to be bonded via the adhesive resin 5. That is, in the bonded body 20, one surface of the adhesive resin 5 is bonded to the film 2 side of one aluminum alloy material 10 and the other surface is bonded to the film 2 side of the other aluminum alloy material 10.

Here, as the adhesive resin 5 in the joined body of the present embodiment, the same adhesive resin as the adhesive resin layer 4 described above can be used. Specifically, an epoxy resin, a urethane resin, a nitrile resin, a nylon resin, an acrylic resin, or the like can be used as the adhesive resin 5. The thickness of the adhesive resin 5 is not particularly limited, but is preferably 10 to 500 μm, more preferably 50 to 400 μm from the viewpoint of improving the adhesive strength.

As described above, in the bonded body 20, both surfaces of the adhesive resin 5 are the coatings 2 of the aluminum alloy material 10 of the first embodiment. In addition, the adhesive strength at the interface between the adhesive resin 5 and the film 2 is not easily lowered, and the adhesion durability is improved. Moreover, in the joined body 20 of this embodiment, the adhesive durability at the interface is improved in all adhesive resins conventionally used for joining aluminum alloy materials without being affected by the type of the adhesive resin 5.

Moreover, like the joined body 21a shown in FIG. 6A or the joined body 21b shown in FIG. 6B, the coating 2 is formed on the surface on which the coating 2 of the aluminum alloy material 10 shown in FIG. It can also be set as the structure which joined the other aluminum alloy material 6 or the resin molding 7 which is not formed.

Here, as the other aluminum alloy material 6 on which the film 2 is not formed, the same material as the base material 3 described above can be used. Specifically, the aluminum alloy material 6 is specified in JIS or approximate to JIS. Various non-heat treatment type or heat treatment type aluminum alloys can be used.

Examples of the resin molded body 7 include glass fiber reinforced plastic (GFRP), carbon fiber reinforced plastic (CFRP), boron fiber reinforced plastic (BFRP), aramid fiber reinforced plastic (AFRP, KFRP), polyethylene fiber reinforced plastic ( A fiber reinforced plastic molded body formed of various fiber reinforced plastics such as DFRP) and Zylon reinforced plastic (ZFRP) can be used. By using these fiber-reinforced plastic molded bodies, it is possible to reduce the weight of the joined body while maintaining a certain strength.

In addition to the above-mentioned fiber reinforced plastic, the resin molded body 7 is made of polypropylene (PP), acrylic-butadiene-styrene copolymer (ABS) resin, polyurethane (PU), polyethylene (PE), polyvinyl chloride (PVC). , Nylon 6,

nylon

6,6, polystyrene (PS), polyethylene terephthalate (PET), polyamide (PA), polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), polyphthalamide (PPA), etc. No resin can be used.

In the joined

bodies

21a and 21b shown in FIG. 6A and FIG. 6B, since one surface of the adhesive resin 5 is joined to the film 2 side of the aluminum alloy material 10, it was used as a member for an automobile, like the joined body 20 described above. At this time, even when exposed to a high temperature and humidity environment, the adhesion durability at the interface is improved without being influenced by the type of the adhesive resin. Moreover, since the joined body 21b shown to FIG. 6B has joined the aluminum alloy material 10 and the resin molding 7, it is lightweight compared with the joined body of aluminum alloy materials, By using this joined body 21b, Further weight reduction of the automobile can be realized. The other configurations and effects of the joined

bodies

21a and 21b shown in FIGS. 6A and 6B are the same as those of the joined body 20 shown in FIG.

Furthermore, like the joined body 22 shown in FIG. 7, the aluminum alloy material 11 with the adhesive resin layer provided with the adhesive resin layer 4 shown in FIG. 3, and the aluminum alloy material 10 not provided with the adhesive resin layer 4 shown in FIG. It can also be set as the structure which joined. Specifically, the film 2 side of the aluminum alloy material 10 is joined to the adhesive resin layer 4 side of the aluminum alloy material 11 with the adhesive resin layer. As a result, the film 2 of the aluminum alloy material 10 and the film 2 of the aluminum alloy material 11 with the adhesive resin layer were arranged to face each other via the adhesive resin layer 4 of the aluminum alloy material 11 with the adhesive resin layer. It has a configuration.

In the joined body 22, both surfaces of the adhesive resin layer 4 are joined to the film 2 of the aluminum alloy material 10 and the film 2 of the aluminum alloy material 11 with the adhesive resin layer, respectively. When 22 is used as a member for an automobile, even if it is exposed to a high-temperature and humid environment, the adhesion durability at the interface is improved without being affected by the type of the adhesive resin. In addition, the structure and effect other than the above in the joined body 22 shown in FIG. 7 are the same as those of the joined body 20 shown in FIG.

Further, as in the joined body 23a shown in FIG. 8A or the joined body 23b shown in FIG. 8B, the coating 2 is formed on the adhesive resin layer 4 side of the aluminum alloy material 11 with the adhesive resin layer provided with the adhesive resin layer 4 shown in FIG. It is also possible to adopt a configuration in which a resin molded body 7 such as another aluminum alloy material 6 or a fiber-reinforced plastic molded body in which no is formed is joined. In these joined

bodies

23a and 23b, since one surface of the adhesive resin layer 4 is joined to the film 2 side of the aluminum alloy material 11 with the adhesive resin layer, the joined body 23 is used as an automobile member in the same manner as the joined body 20 described above. When used in the above, even when exposed to a high-temperature wet environment, the adhesion durability at the interface is improved without being affected by the type of the adhesive resin.

Moreover, since the joined body 23b shown to FIG. 8B has joined the aluminum alloy material 11 with an adhesive layer, and the resin molding 7, it is lightweight compared with the joined body of aluminum alloy materials, and weight reduction is calculated | required. It is suitable for the members of automobiles and vehicles. The structures and effects of the joined

bodies

23a and 23b shown in FIGS. 8A and 8B other than those described above are the same as those of the joined body 20 shown in FIG.

[Method of manufacturing joined body]
As a manufacturing method of the joined bodies 20 to 23, particularly a joining method, a conventionally known joining method can be used. The method for forming the adhesive resin 5 on the aluminum alloy material is not particularly limited. For example, an adhesive sheet prepared in advance using the adhesive resin 5 may be used, or the adhesive resin 5 may be formed on the surface of the film 2. You may form by spraying or apply | coating to. The bonded bodies 20 to 23 may be coated with press oil on their surfaces before being processed into automobile members, similarly to the aluminum alloy material 10 and the aluminum alloy material 11 with an adhesive layer.

Although not shown, when an aluminum alloy material (with an adhesive resin layer) having a film 2 formed on both surfaces is used for the joined body of the present embodiment, these (adhesive) are bonded via an adhesive resin or an adhesive resin layer. It becomes possible to further join an aluminum alloy material (with a resin layer), another aluminum alloy material on which a film is not formed, or a resin molded body.

(Third embodiment)
Next, the automotive member according to the third embodiment of the present invention will be described. The member for motor vehicles of this embodiment uses the joined object of a 2nd embodiment mentioned above, for example, is a panel for motor vehicles.

Further, the manufacturing method of the automobile member of the present embodiment is not particularly limited, but a conventionally known manufacturing method can be applied. For example, the joined members 20 to 23b shown in FIGS. 5 to 8B are cut or pressed to produce a member for an automobile having a predetermined shape.

Since the automobile member of the present embodiment is manufactured from the joined body of the second embodiment described above, even if it is exposed to a high-temperature and humid environment, the effects of the adhesive resin or the adhesive resin layer and the hydration of the film are hardly affected. Without receiving, elution of the aluminum alloy substrate can be suppressed. As a result, in the automotive member of this embodiment, it is possible to suppress interfacial peeling when exposed to a high-temperature and humid environment, and to suppress a decrease in adhesive strength.

Hereinafter, the effects of the present invention will be described in detail with reference to examples and comparative examples of the present invention. In this example, an aluminum alloy material was produced by the following method and conditions, and its adhesion durability and the like were evaluated.

<Example 1>
Using a 6000 series aluminum alloy of JIS 6016 (Mg: 0.54 mass%, Si: 1.11 mass%, Cu: 0.14 mass%), an aluminum alloy cold-rolled sheet having a thickness of 1 mm was produced. And this cold-rolled board was cut | disconnected to length 100mm and width 25mm, and it was set as the base material. Next, this base material was heat-treated to an actual temperature of 550 ° C. and cooled. Subsequently, the substrate was alkali degreased with an aqueous solution of pH 13 containing potassium hydroxide at 50 ° C. for 40 seconds, and then pickled with a solution of pH 1 containing sulfuric acid and hydrofluoric acid at 50 ° C. for 40 seconds. Thereafter, an aqueous solution containing 0.018% by mass of sodium metasilicate (hereinafter also referred to as an aqueous sodium silicate solution) was uniformly applied to the surface with a bar coater. Then, it heat-dried at 100 degreeC for 1 minute, and obtained the aluminum alloy material of Example 1 which has a film | membrane on the surface.

<Example 2>
An aluminum alloy material of Example 2 was obtained in the same manner as in Example 1 except that the sodium metasilicate concentration in the aqueous sodium silicate solution was 0.055% by mass.

<Example 3>
An aluminum alloy material of Example 3 was obtained in the same manner as Example 1 except that the sodium metasilicate concentration in the sodium silicate aqueous solution was 0.084% by mass.

<Example 4>
An aluminum alloy material of Example 4 was obtained in the same manner as in Example 1 except that the sodium metasilicate concentration in the aqueous sodium silicate solution was 0.12% by mass.

<Example 5>
An aluminum alloy material of Example 5 was obtained in the same manner as in Example 1 except that the sodium metasilicate concentration in the aqueous sodium silicate solution was 0.24% by mass.

<Example 6>
Example 6 was carried out in the same manner as in Example 1 except that the alkaline degreasing time was 20 seconds, the pickling with sulfuric acid hydrofluoric acid was not performed, and the sodium metasilicate concentration in the sodium silicate aqueous solution was 0.084% by mass. An aluminum alloy material was obtained.

<Example 7>
Example 1 except that the alkali degreasing time was 100 seconds, the pickling time with sulfuric acid hydrofluoric acid was 100 seconds, and the sodium metasilicate concentration in the sodium silicate aqueous solution was 0.084% by mass, The aluminum alloy material of Example 7 was obtained.

<Example 8>
Example 1 except that kanemite (trade name: Prefeed, manufactured by Tokuyama Siltec Co., Ltd., n / m = 2) was used as the silicate compound in the silicate aqueous solution at a concentration of 0.10% by mass. The aluminum alloy material of Example 8 was obtained.

<Example 9>
Example 9 is the same as Example 1 except that No. 3 water glass (manufactured by Wako Pure Chemical Industries, n / m = 3) is used at a concentration of 0.09% by mass as the silicate compound in the silicate aqueous solution. An aluminum alloy material was obtained.

<Comparative Example 1>
An aluminum alloy material of Comparative Example 1 was obtained in the same manner as in Example 1 except that the sodium metasilicate concentration in the aqueous sodium silicate solution was 0.61% by mass.

<Comparative Example 2>
An aluminum alloy material of Comparative Example 2 was obtained in the same manner as in Example 1 except that the sodium metasilicate concentration in the aqueous sodium silicate solution was 0.0061% by mass.

<Comparative Example 3>
An aluminum alloy material of Comparative Example 3 was obtained in the same manner as in Example 1 except that the treatment with the sodium silicate aqueous solution was not performed.

<Comparative Example 4>
An aluminum alloy material of Comparative Example 4 was obtained in the same manner as in Example 1 except that the sodium metasilicate concentration in the aqueous sodium silicate solution was 0.12% by mass and the surface was washed with water after the treatment.

<Comparative Example 5>
An aluminum alloy material of Comparative Example 5 was obtained in the same manner as in Example 1 except that alkali degreasing and pickling were not performed and the sodium metasilicate concentration in the aqueous sodium silicate solution was 0.084% by mass.

<Comparative Example 6>
An aluminum alloy material of Comparative Example 6 was obtained in the same manner as in Example 1 except that the pickling time with sulfuric acid hydrofluoric acid was set to 300 seconds and the sodium metasilicate concentration in the sodium silicate aqueous solution was set to 0.084% by mass. .

(IR spectrum measurement)
The aluminum alloy materials according to each of Examples and Comparative Examples having a coating on the surface were subjected to FT-IR (Fourier transform infrared spectrophotometer: Magna-750 spectrometer manufactured by Nicolet) using parallel polarized light with an incident angle of 75 °. ) the IR spectrum was measured by analyzing, reading the spectral intensity (absorbance) at a wave number region of the frequency domain and 1550 - 1650 cm ^-1 in the coating process 1440 - from the difference spectrum before and after 1540 cm ^-1. The results are shown in Table 1. In Table 1, “−” means that the absorbance was not measured.

(Element concentration measurement of film components)
The elemental component concentration in the film was measured while sputtering in the film thickness direction by high-frequency glow discharge optical emission spectrometry (GD-OES: model JY-5000RF manufactured by Horiba Joban Yvon). Aluminum (Al), magnesium (Mg) ), Sodium (Na), potassium (K), lithium (Li), copper (Cu), iron (Fe), titanium (Ti) and other metal elements, and oxygen (O), nitrogen (N), carbon (C ), Silicon (Si), sulfur (S), and other elements were measured for the amount of each component. For magnesium (Mg), sodium (Na), potassium (K), lithium (Li), copper (Cu), and silicon (Si), the maximum concentration in the film was defined as the film concentration in the film. Since aluminum (Al) is affected by the substrate near the interface between the substrate and the coating, the concentration of the outermost surface is the coating concentration of aluminum (Al). Here, in the calculation of the concentrations of these elements, oxygen (O) and carbon (C) are particularly susceptible to contamination on the outermost surface and in the vicinity thereof. From the above, in the concentration calculation of each element, the concentration was calculated excluding oxygen (O) and carbon (C). Oxygen (O) is highly likely to be affected by contamination at the outermost surface and in the vicinity thereof, and it is difficult to measure the exact concentration, but all sample films contain oxygen (O). It was clear that The results are shown in Table 1.

(Measurement of coating amount)
The coating amount was measured by fluorescent X-ray. Specifically, the amount of silicon in the film is measured with fluorescent X-rays, and the calibration curve is used to convert the intensity of the fluorescent X-rays and the amount of film, and further subtract the silicon amount contained in the substrate. did. The results are shown in Table 1.

<Measurement of etching amount>
The amount of etching is the amount of dissolution of the oxide film and the base material including the oxide film, and the amount of decrease in weight before and after the etching treatment was measured and estimated as the thickness (film thickness). In addition, the conversion from the decrease in weight to the film thickness was performed by calculating the aluminum thickness using the aluminum density of 2.7 g / cm ³ for convenience.

<Cohesive failure rate (adhesion durability)>
9A and 9B are diagrams schematically showing a method of measuring the cohesive failure rate, FIG. 9A is a side view, and FIG. 9B is a plan view. As shown in FIGS. 9A and 9B, the end portions of two

test materials

31a and 31b (25 mm width) having the same configuration are wrapped with a thermosetting epoxy resin adhesive resin with a wrap length of 10 mm (adhesion area: 25 mm × 10 mm). ).
The adhesive resin 35 used here is a thermosetting epoxy resin-based adhesive resin (bisphenol A type epoxy resin amount 40 to 50 mass%). Further, a small amount of glass beads (average particle size 250 μm) was added to the adhesive resin 35 so that the thickness of the adhesive resin 35 was 250 μm.
After superposition, they were dried at room temperature for 30 minutes, and then heated at 170 ° C. for 20 minutes to carry out a thermosetting treatment. Then, it left still at room temperature for 24 hours, and produced the adhesion test body.

The prepared adhesion test specimen was immersed in an aqueous sodium chloride solution having a concentration of 5% at 40 ° C. for 20 days and then pulled at a rate of 50 mm / min with a tensile tester to evaluate the cohesive failure rate of the adhesive resin at the bonded portion. The cohesive failure rate was calculated based on Equation 1 below. In addition, in the following numerical formula 1, the test specimen a was used as one side after the tension of the adhesion test specimen, and the test specimen b was used as the other side.

Three samples were prepared for each test condition, and the cohesive failure rate was the average value of the three samples. Further, the evaluation criteria are excellent when the cohesive failure rate is less than 60% as bad (x), 60% or more and less than 70% is slightly good (Δ), and 70% or more and less than 90% is good (◯) is 90% or more (◎). The results are shown in Table 1.

As shown in Table 1, in the aluminum alloy material of Comparative Example 1, the Si concentration in the film is higher than the range specified in the present invention, and has no absorption in the wave number region of 1550 to 1650 cm ⁻¹ . The adhesion durability was poor. The aluminum alloy material of Comparative Example 1 had absorption in the wave number region of 1440 to 1540 cm ⁻¹ .
In the aluminum alloy material of Comparative Example 2, the Si concentration in the film is lower than the range specified in the present invention, and the absorbance in the wave number region of 1550 to 1650 cm ⁻¹ is lower than the range specified in the present invention. The adhesion durability was poor.
In addition, the aluminum alloy material of Comparative Example 3 has a Si concentration in the film lower than the range specified in the present invention, and has no absorption in the wave number region of 1550 to 1650 cm ⁻¹ and has poor adhesion durability. It was. The aluminum alloy material of Comparative Example 3 did not absorb even in the wave number region of 1440 to 1540 cm ⁻¹ .
Further, the aluminum alloy material of Comparative Example 4 had no absorption in the wave number region of 1550 to 1650 cm ⁻¹ and had poor adhesion durability. The aluminum alloy material of Comparative Example 4 did not absorb even in the wave number region of 1440 to 1540 cm ⁻¹ .
Further, the aluminum alloy material of Comparative Example 5 had a Mg concentration in the film higher than the range specified in the present invention, and had poor adhesion durability.
Moreover, the aluminum alloy material of Comparative Example 6 had a Cu concentration in the film higher than the range specified in the present invention, and had poor adhesion durability.

On the other hand, the aluminum alloy materials of Examples 1 to 9 that satisfy each requirement defined in the present invention had good wet durability under a high temperature and high humidity environment.

Although the invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on a Japanese patent application filed on May 10, 2016 (Japanese Patent Application No. 2016-094918) and a Japanese patent application filed on November 7, 2016 (Japanese Patent Application No. 2016-217096). Which is incorporated by reference in its entirety.

2 Coating 3 Base material 4

Adhesive resin layer

5, 35

Adhesive resin

6, 10 Aluminum alloy material 7 Resin molded body 11 Aluminum alloy material with

adhesive resin layer

20, 21a, 21b, 22, 23a, 23b Joined

body

31a, 31b Material

Claims

An aluminum alloy substrate;
An aluminum alloy material provided with a film made of an oxide of aluminum containing silicon, formed on at least a part of the surface of the aluminum alloy substrate,
The film has a peak peak of absorption in a wave number region of 1550 to 1650 cm −1 in a difference spectrum before and after the film treatment obtained by applying parallel polarized light with an incident angle of 75 ° by Fourier transform infrared spectroscopy. The absorbance at the peak top is 0.001 or more, and the film contains 20 atomic% or more and less than 80 atomic% of Si and 0.1 atomic% or more and less than 30 atomic% of Mg, and 0% of Cu. Aluminum alloy material restricted to less than 6 atomic%.
The aluminum alloy material according to claim 1, wherein the difference spectrum has no absorption in a wave number region of 1440 to 1540 cm -1 .
The aluminum alloy material according to claim 1, which is used by directly bonding an adhesive resin to the film.
An aluminum alloy material with an adhesive resin layer, wherein an adhesive resin layer is directly formed on the film of the aluminum alloy material according to claim 1.
The aluminum alloy material with an adhesive resin layer according to claim 4, wherein the adhesive resin layer contains an organic-inorganic coupling agent.
The aluminum alloy material with an adhesive resin layer according to claim 4, wherein the adhesive resin layer includes an epoxy resin.
A joined body obtained by joining the aluminum alloy material according to any one of claims 1 to 3 and another member via an adhesive resin.
A joined body in which the aluminum alloy material with an adhesive resin layer according to any one of claims 4 to 6 and another member are joined via the adhesive resin layer.
A method for producing an aluminum alloy material comprising a film forming step of forming a film made of an oxide of aluminum containing silicon on at least a part of a surface of an aluminum alloy substrate,
The film forming step includes a heat treatment stage for forming an oxide film on the surface of the aluminum alloy substrate, an etching treatment stage and a silicate treatment stage after the heat treatment stage, and the silicate treatment stage includes After the etching step or at the same time as the etching step,
The manufacturing method of the aluminum alloy material which processes the said oxide film with the aqueous solution which contains 0.008 mass% or more and less than 0.5 mass% of silicate as the said silicate process step.
10. The method for producing an aluminum alloy material according to claim 9, wherein washing with water is not performed after the treatment with the aqueous solution containing silicate.
The method for producing an aluminum alloy material according to claim 9 or 10, wherein an etching amount in the etching treatment stage is controlled to be less than 700 nm.