JP6705694B2 - Aluminum alloy material, aluminum alloy material with adhesive resin layer, bonded body, and method for manufacturing aluminum alloy material - Google Patents

Description

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

From the viewpoint of reducing the weight of members used for transportation machines such as automobiles, ships, and aircraft, attention has been focused on the development of technology for joining dissimilar materials such as carbon fiber, aluminum alloys, and steel materials having different strengths, materials, and masses. There is. 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. However, in a high-humidity environment, water enters the interface between the metal and the adhesive resin, corrosion/deterioration of the metal surface occurs, and peeling easily occurs at the interface between the metal and the adhesive resin, resulting in a significant decrease in adhesive strength. .. Therefore, the 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 determines the adhesive durability.

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

For example, Patent Document 1 discloses that an adhesive formed on a metal such as aluminum by treating a metal such as aluminum with an aqueous composition containing a tetraalkyl silicate such as tetraethyl orthosilicate and a hydrated oxide sol such as silica sol. And other techniques for improving the initial adhesion of the coating film and the long-term stability of the adhesion.

Further, in Patent Document 2, by treating the surface of a galvanized steel sheet with an acidic aqueous solution containing a silicate compound, a film having a Si-O-Si bond is generated and, at the same time, Si-OH/Si-. There is described a method of improving the corrosion resistance and the coating secondary adhesion by defining the O-Si bond amount ratio to be a specific value or more by the intensity ratio of the IR spectrum.

Patent Document 3 describes a method of improving corrosion resistance by rinsing the surface of a galvanized steel sheet with an aqueous solution containing a silicic acid compound and then treating the surface with a silane coupling agent.

Further, in Patent Document 4, a solution containing a silicate ester, an inorganic inorganic salt and polyethylene glycol and further containing a silane coupling agent is applied on a zinc-based plated steel sheet and dried to form a film. Describes a method for improving paint adhesion and white rust resistance.

Further, Patent Document 5 discloses a method of improving paint adhesion by treating the surface of a metal material such as aluminum or aluminum alloy with an aqueous solution containing water glass such as sodium water glass and silane such as aminosilane. Have been described.

Japanese Patent Publication No. 10-510307 Japanese Patent No. 5130496 US Pat. No. 5,108,793 Japanese Patent No. 3289769 Special table 2014-502287 gazette

However, in the method described in Patent Document 1, the adhesive strength is remarkably reduced by the long-term wet deterioration test, and therefore the adhesive durability cannot be said to be sufficient.

Further, the methods described in Patent Documents 2 to 5 are intended only for the purpose of preventing corrosion of the metal surface and improving the adhesiveness of the paint. Therefore, the formed film has a large thickness, but a thick film has a low mechanical strength of the film itself, becomes brittle against tension and stress, and high adhesive strength cannot be obtained.

In view of the above problems, the present invention, even when exposed to a high temperature wet environment, the adhesive strength is less likely to decrease, aluminum alloy material excellent in adhesive durability, aluminum alloy material with an adhesive resin layer, aluminum alloy A main object of the present invention is to provide a joined body using a material or an aluminum alloy material with an adhesive resin layer, and a method for manufacturing an aluminum alloy material.

In order to solve the above-mentioned subject, the present inventor has conducted earnest experimentation and as a result, the amount of Mg, the amount of Si, and the amount of Cu were within a specific range on the surface of the aluminum substrate, and in the FT-IR spectrum. The inventors have found that excellent adhesion durability can be obtained by forming a film made of an oxide of aluminum containing silicon, which has a specific absorption, and arrived at the present invention.

That is, the present invention is an aluminum alloy base material, and an aluminum alloy material having a film formed on at least a part of the surface of the aluminum alloy base material, the film comprising an oxide of aluminum containing silicon, wherein the film is In the difference spectrum before and after the film treatment obtained by injecting parallel polarized light having an incident angle of 75° by Fourier transform infrared spectroscopy, it has two absorption bands in the wave number range of 1000 to 1300 cm ⁻¹ , The absorption band is in the range of wave numbers of 1080 to 1140 cm ⁻¹ and wave numbers of 1180 to 1240 cm ⁻¹ , and the film has Si of 20 atomic% or more and less than 70 atomic% and Mg of 0.1 atomic% or more and less than 30 atomic %. Provided is an aluminum alloy material which contains Cu and is regulated to less than 0.6 atomic %.

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

In the aluminum alloy material of the present invention, it is preferable that the coating film does not substantially contain a particulate inorganic compound having a diameter of 1 nm or more.
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 the adhesive resin layer of the present invention, the adhesive resin layer preferably contains an organic-inorganic coupling agent.

Moreover, in the aluminum alloy material with an adhesive resin layer of the present invention, it is preferable that the adhesive resin layer contains an epoxy resin.

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

Furthermore, the present invention also provides a joined body in which the above-mentioned 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, which comprises 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 the aluminum alloy substrate, wherein the film forming step is A heat treatment step of 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, the silicate treatment step being after the etching treatment step or the etching. Also provided is a method for producing an aluminum alloy material, which is simultaneous with the treatment step and, as the silicate treatment step, treats the oxide film with an aqueous solution containing 0.02% by mass to 2% by mass of a tetraalkyl silicate or an oligomer thereof.

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

In the method for producing an aluminum alloy material of the present invention, it is preferable that the aqueous solution does not substantially contain a particulate inorganic compound having a diameter of 1 nm or more.

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

According to the present invention, it is possible to realize an aluminum alloy material in which the adhesive strength does not easily decrease even when exposed to a high temperature and wet environment and the adhesive durability is excellent.

FIG. 1 is a sectional view schematically showing the structure 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 modified example of the first embodiment of the present invention. FIG. 4 is a flowchart showing a method for manufacturing the aluminum alloy material with the adhesive resin layer shown in FIG. FIG. 5: is sectional drawing which shows typically the structural example of the joined body which concerns on the 2nd Embodiment of this invention. FIG. 6A is a 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 sectional drawing which shows typically the other structural example of the joined body which concerns on the 2nd Embodiment of this 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 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 the method for measuring the cohesive failure rate. FIG. 9B is a plan view schematically showing the method for measuring the cohesive failure rate.

Hereinafter, modes for carrying out the present invention will be described in detail. 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.
The aluminum alloy material according to the present embodiment is an aluminum alloy material having an aluminum alloy base material and a film formed on at least a part of the surface of the aluminum alloy base material and made of an oxide of aluminum containing silicon. The film has two absorption bands in the wave number range of 1000 to 1300 cm ⁻¹ in the difference spectrum before and after the film treatment, which is obtained by injecting parallel polarized light having an incident angle of 75° by Fourier transform infrared spectroscopy. The two absorption bands are in the ranges of wave numbers of 1080 to 1140 cm ⁻¹ and wave numbers of 1180 to 1240 cm ⁻¹ , and the coating film contains Si of 20 atomic% or more and less than 70 atomic% and Mg of 0.1 atomic% or more. An aluminum alloy material containing less than 30 atomic% and Cu regulated to less than 0.6 atomic %.

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

[Base material 3]
The base material 3 is made of an aluminum alloy. The type of aluminum alloy forming the base material 3 is not particularly limited, and various non-heat-treatment type or heat-treatment type aluminums defined in JIS or similar to JIS are used depending on the use of the member to be processed. The alloy can be appropriately selected and used. 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 treatment type aluminum alloy, there are Al-Cu-Mg based alloys (2000 series), Al-Mg-Si based alloys (6000 series) and Al-Zn-Mg based alloys (7000 series).

For example, when the aluminum alloy material 10 of the present embodiment is used for a member for automobiles, the 0.2% proof stress of the base material 3 is preferably 100 MPa or more from the viewpoint of strength. Aluminum alloys capable of forming a base material satisfying such characteristics include those containing a relatively large amount of magnesium, such as 2000 series, 5000 series, 6000 series and 7000 series, and these alloys are required. May be tempered according to Further, among various aluminum alloys, it is preferable to use the 6000 series aluminum alloy because it is excellent in age hardening ability, has a relatively small amount of alloying elements and is excellent in scrap recyclability and formability.

[Film 2]
The coating 2 is a coating formed on at least a part of the surface of the substrate 3 and made of an oxide of aluminum containing silicon. In the aluminum alloy material 10 of the present embodiment, the coating film 2 has a wave number of 1000 in the difference spectrum before and after the coating treatment, which is obtained by injecting parallel polarized light with an incident angle of 75° by Fourier transform infrared spectroscopy (FT-IR). Has two absorption bands in the range of ˜1300 cm ⁻¹ , and the two absorption bands are in the ranges of wave numbers of 1080 to 1140 cm ⁻¹ and 1180 to 1240 cm ⁻¹ , and the film 2 contains 20 atomic% of Si. The above content is less than 70 atomic %, the content of Mg is 0.1 atomic% or more and less than 30 atomic %, and the Cu content is regulated to less than 0.6 atomic %. The film 2 is a film that is denser and has a higher corrosion resistance than an ordinary aluminum oxide film, and is provided to increase the bonding strength with an adhesive and to improve the adhesion durability. Hereinafter, a suitable range of the amount of each component 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 base material 3, but the present embodiment is not limited to this. For example, the film 2 may be formed only on a part of the surface of the base material 3. Further, the coating film 2 may be formed on both surfaces of the base material 3.

<FT-IR spectrum>
The thin film derived from tetraalkyl silicate or its oligomer has two different absorption bands derived from asymmetric stretching vibration of Si—O—Si bond in the wave number range of 1000 to 1300 cm ⁻¹ , and these two absorption bands are , Respectively in the range of 1,080 to 1140 cm ⁻¹ and 1,180 to 1240 cm ⁻¹ . However, in these two absorption bands, the peaks are averaged as the film becomes thicker, resulting in a single broad peak. Here, if the film becomes thick, it becomes a brittle film having low mechanical strength, and it becomes impossible to obtain high adhesion durability. Therefore, it is important to have two different absorption bands in the relevant area in order to determine whether or not the film is a suitable film having excellent adhesion durability. In the aluminum alloy material 10 of the present embodiment, the film 2 is the difference spectrum before and after coating treatment with FT-IR, range of wave numbers 1080～1140Cm ^-1 and a wavenumber 1180～1240Cm ^-1 derived from tetraalkyl silicate or its oligomer Since it has two absorption bands and the film is sufficiently thin, it has high adhesion durability. In the present specification, “having an absorption band in a certain wave number range” means having a maximum absorption wavelength in the wave number range. The shape of the absorption band may have an inflection point, and may have a peak or a shoulder.

The film having the above-described two absorption bands in the difference spectrum before and after the film treatment by FT-IR is formed, for example, by subjecting an oxide film formed on an aluminum alloy substrate to a silicate treatment described later. You can Here, in the present specification, the silicate treatment means a treatment using a tetraalkyl silicate or an oligomer thereof. When an oxide film on an aluminum alloy substrate is silicate-treated with a tetraalkyl silicate or an oligomer thereof, and the film after the treatment is thin, in the difference spectrum before and after the film treatment by FT-IR, the wave number of 1080 to 1140 cm ^{− 1} and an absorption band in the wave number range of 1180 to 1240 cm ⁻¹ .
Incidentally, the difference spectrum before and after the film treatment, 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 base material on which the film is not formed, Is the difference.

In the present embodiment, when the coating film 2 contains a particulate inorganic compound having a diameter of 1 nm or more (hereinafter, also simply referred to as “particulate inorganic compound”), the coating film becomes thick and the adhesive strength and the adhesive durability may be reduced. There is. Therefore, it is preferable that the film 2 does not substantially contain the particulate inorganic compound. In addition, "the coating film does not substantially contain the particulate inorganic compound" is not limited to an embodiment that does not contain the particulate inorganic compound at all, it is allowed to contain the particulate inorganic compound at the impurity level. It Specifically, it is permissible that the particulate inorganic compound is contained up to 5% by mass or less with respect to the entire coating. Examples of the particulate inorganic compound include sols of inorganic oxides such as silica and alumina. The diameter of the particulate inorganic compound represents the diameter of the solid content after the treatment liquid is dried, which is observed by a transmission electron microscope (TEM) or the diluted treatment liquid is measured by a submerged particle counter.

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

Further, in a high temperature wet environment where water, oxygen, etc. permeate, it causes hydration of the interface with the adhesive resin and corrosion of the base material, and reduces 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 film 2 is restricted to less than 30 atomic %. Thereby, the adhesion durability can be improved. From the viewpoint of improving the adhesion durability, the Mg content of the coating film 2 is preferably less than 25 atom %, more preferably less than 20 atom %, and even more preferably less than 10 atom %.

On the other hand, the lower limit of the Mg content of the film 2 is 0.1 atom% or more from the viewpoint of economy. The Mg content in the film 2 referred to here can be measured by a high frequency glow discharge optical emission spectroscopy (GD-OES).

The method for adjusting the Mg content of the film 2 is not particularly limited, but examples thereof include acidic solutions of acids such as nitric acid, sulfuric acid and hydrofluoric acid or mixed acids, or potassium hydroxide, sodium hydroxide, silicic acid. A method of surface-treating with an alkaline solution containing salts and carbonates can be applied. This method adjusts the Mg content of the film 2 by dissolving magnesium in an acid or alkaline solution. By adjusting the treatment time, temperature, concentration and pH of the surface treatment solution, The amount of Mg can be in the range described above. Even if Mg is contained to the extent of impurity elements, Mg may be concentrated in the film 2 when heat treatment at a high temperature is performed, and adjustment by surface treatment with acid or alkali may occur. Are required as appropriate. It is also possible to adjust the surface treatment chemicals by incorporating Mg ions therein.

<Si content: 20 atomic% or more and less than 70 atomic%>
Since silicon has the effect of improving the corrosion resistance of the film 2 and stabilizing it in a wet environment, the inclusion of silicon in the film 2 makes it possible to suppress a decrease in bonding strength.

However, when the Si content in the coating film 2 is less than 20 atomic %, the above-mentioned effect tends to be small, and when the Si content is 70 atomic% or more, the spot weldability and the uniformity of the chemical conversion treatment are low. It tends to decrease. Therefore, in the aluminum alloy material 10 of the present embodiment, the Si content in the film 2 is set to 20 atom% or more and less than 70 atom %.

From the viewpoint of improving the adhesion durability, the Si content in the film 2 is preferably 25 atom% or more, and more preferably 30 atom% or more. Further, from the viewpoint of spot weldability and uniformity of chemical conversion treatment, the Si content in the film 2 is preferably less than 65 atom %, and more preferably less than 60 atom %.

The Si content in the coating film 2 is adjusted, for example, by performing a surface treatment with an acid or an alkali, similarly to the method described as the method for adjusting the amount of Mg. Further, it is adjusted depending on the conditions of the treatment with the aqueous silicate solution, which will be described later.

<Cu content: less than 0.6 atom%>
When the base material 3 is excessively etched by a degreasing process, a pickling process, or the like when forming the coating film 2, Cu contained in the base material 3 is concentrated on the surface, and the Cu content of the coating film 2 is increased. .. The presence of Cu on the surface of the coating 2 reduces the adhesion with the adhesive resin that is directly bonded to the surface of the coating 2.

Therefore, in the aluminum alloy material of the present embodiment, the Cu content in the film 2 is restricted to less than 0.6 atom %. The amount of Cu in the film 2 is preferably less than 0.5 atom% from the viewpoint of improving the adhesiveness with the 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, and for example, the same treatment method as described in the numerical 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 concentrations such as the amount of Mg, the amount of Si, and the amount of Cu in the film 2 can be measured by, for example, a high-frequency glow discharge optical emission spectroscopy (GD-OES: Glow Discharge-Optical Emission Spectroscopy). In this 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), copper (Cu), metal elements such as iron (Fe) and titanium (Ti), and elements such as silicon (Si) are measured, and the content of Mg, Si, Cu, Al, etc. is expressed in percentage from the result. The calculated value is used as the amount of each element.

<Film thickness>
The film thickness of the film 2 is preferably 1 to 30 nm. When the film thickness of the coating film 2 is less than 1 nm, the rust preventive oil used for producing the base material 3 and the ester in the press oil used for producing the joined body or the automobile member from the aluminum alloy material 10 Adsorption of components is suppressed. Therefore, the degreasing property, the chemical conversion processability, and the adhesion durability of the aluminum alloy material 10 can be secured without providing the film 2. However, in order to control the film thickness of the coating film 2 to be less than 1 nm, excessive acid cleaning or the like is required, so that the productivity is deteriorated and the practicality is likely to be lowered. In addition, alkali degreasing and excessive etching with acid cause the Cu contained in the base material 3 to be concentrated on the surface, which 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 the surface is likely to have irregularities. When the surface of the coating film 2 has irregularities, for example, in automobile applications, chemical conversion spots are likely to occur during the chemical conversion treatment performed before the coating step, resulting in 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 viewpoint of chemical conversion and productivity.

[Production method]
Next, a method for manufacturing the aluminum alloy material of this embodiment will be described. 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 the present embodiment, a base material manufacturing step S1 and a film forming step S2 are performed. Hereinafter, each step will be described.

<Step S1: Base material manufacturing process>
The shape of the base material is not particularly limited, and depending on the shape and the like of the member manufactured using the aluminum alloy material, in addition to the plate shape, a cast material, a forged material, an extruded material (for example, a hollow rod shape), etc. It may have any shape that can be taken as. In the base material manufacturing step S1, for example, when a plate-shaped base material (substrate) is manufactured, 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 (melt casting step). Next, the produced ingot is subjected to homogenizing heat treatment (homogenizing heat treatment step). Then, the homogenized heat-treated ingot is hot-rolled to produce a hot-rolled sheet (hot-rolling step). Then, this hot-rolled sheet is subjected to rough annealing or intermediate annealing at 300 to 580° C., and subjected to cold rolling at a final cold rolling rate of 5% or more at least once to obtain a cold-rolled sheet (substrate) having a predetermined sheet thickness. Is obtained (cold rolling step).

In the cold rolling step, it is preferable that the temperature of the rough annealing or the intermediate annealing is 300° C. or higher, and thereby the effect of improving the formability is more exerted. Further, the temperature of the rough annealing or the intermediate annealing is preferably set to 580° C. or lower, which facilitates suppressing the deterioration of the formability due to the occurrence of burning. On the other hand, the final cold rolling rate is preferably 5% or more, whereby the effect of improving the formability is more exerted. The conditions for homogenizing heat treatment and hot rolling are not particularly limited, and the conditions for obtaining a hot-rolled sheet can be used. Moreover, the intermediate annealing may not be performed.

<Step S2: Film forming step>
In the film forming step (step S2), a film is formed on at least a part (that is, a part or all) of the surface of the base material manufactured in the base material manufacturing step of step S1. In the present embodiment, specifically, the film forming step (step S2) is, for example, a heat treatment step of heat treating the base material 3 to form an oxide film, an etching treatment step after the heat treatment step, and a silicate. And a processing stage. Here, as a silicate treatment step, treatment is performed with an aqueous solution containing tetraalkyl silicate or an oligomer thereof. Thereby, the film is formed such that the amount of Mg, the amount of Si, and the amount of Cu in the film fall within a specific range and that the film has a specific absorption in the FT-IR spectrum.

As the heat treatment in the heat treatment step, 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. The heat treatment also has the 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 treatment type aluminum alloy, and an annealing is performed when the substrate 3 is formed of a non-heat treatment type aluminum alloy. It is a heat treatment in (final annealing).

From the viewpoint of improving strength, this heat treatment is preferably rapid heating at a heating rate of 100° C./min or more. Further, by setting the heating temperature to 400° C. or higher and performing rapid heating, the strength of the aluminum alloy material 10 and the strength of the aluminum alloy material 10 after being heated (baked) after coating can be further increased. On the other hand, by setting the heating temperature to 580° C. or lower and performing rapid heating, it is possible to suppress deterioration in formability due to occurrence of burning. Further, from the viewpoint of improving the strength, the holding time in the heat treatment is preferably 3 to 30 seconds. Thus, when the base material 3 is heated at a heating temperature of 400 to 580° C., an oxide film having a film thickness of 1 to 30 nm is formed on the surface of the base material 3, for example. Before the heat treatment, alkali degreasing or the like may be performed if necessary.

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

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

In the case of carrying out the alkali cleaning, it is preferable to carry out the pickling after the alkali cleaning. The reason for this is as follows. That is, it is difficult to remove Mg on the surface of the base material by alkali cleaning, and it is necessary to increase the etching amount due to the presence of Mg on the surface of the base material. However, this is because it is necessary to remove Mg by pickling, because an increase in the amount of etching causes a concentration of Cu.

Moreover, it is preferable to perform rinsing after cleaning with each chemical. 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, ion-exchanged water, and the like.

Excessive etching of an aluminum alloy containing copper causes concentration of copper on the surface and causes deterioration of the adhesive resin in a high temperature wet environment which is a deterioration environment. Therefore, 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 amount of dissolution of the oxide film or the base material including the oxide film, and the amount of weight loss before and after the etching treatment is measured to obtain the thickness (film thickness). ) Can be estimated as For the sake of convenience, the conversion of the weight reduction amount into the film thickness is performed by using the density of aluminum: 2.7 g/cm ³ and calculating it as the thickness of aluminum. In addition, when a part of the base material under the oxide film is also etched in addition to the oxide film, the total etching amount of the oxide film and the base material is the above etching amount.

Further, in the silicate treatment step, the substrate having an oxide film is treated with an aqueous solution containing tetraalkyl silicate or an oligomer thereof (hereinafter, also referred to as silicate aqueous solution). Here, the treatment with the silicate aqueous solution includes application of the silicate aqueous solution, dipping in the silicate aqueous solution, and the like. When the treatment with the aqueous silicate solution is carried out, the aluminum oxide film becomes a dense film containing silicon and is rich in corrosion resistance, and the strength of the film itself is improved and the corrosion resistance is also improved. The silicate treatment step is performed as the final step of substantially forming a film in the film forming step, and pickling is not performed after the treatment with the aqueous silicate solution. However, drying after the treatment with the aqueous silicate solution and washing with water as necessary are included in the silicate treatment step.

The concentration of the tetraalkyl silicate or its oligomer in the silicate aqueous solution applied to the oxide film is preferably 0.02% by mass or more and 2% by mass or less. When the concentration of the tetraalkyl silicate or its oligomer in the silicate aqueous solution is 0.02% by mass or more, the film becomes dense and a film excellent in strength and corrosion resistance can be formed. From the same viewpoint, the concentration of the tetraalkyl silicate or the oligomer thereof in the silicate aqueous solution is more preferably 0.03 mass% or more, still more preferably 0.08 mass% or more. On the other hand, if the concentration of the tetraalkyl silicate or its oligomer in the aqueous silicate solution is excessively high, the coating becomes too thick and the adhesion durability may be significantly reduced. Therefore, from the viewpoint of preventing this, the concentration of the tetraalkyl silicate in the aqueous silicate solution is preferably 2% by mass or less, more preferably 1% by mass or less, and further preferably 0.8% by mass or less. is there.

When preparing the silicate aqueous solution, it is preferable to first add a predetermined amount of tetraalkyl silicate to ethanol and then dilute it with water to a predetermined concentration. By doing so, it becomes easy to prepare a uniform aqueous solution. The amount of ethanol is preferably 5 to 20 vol% with respect to water.

Further, since tetraalkyl silicate is excessively polymerized under basic conditions, it is necessary to adjust the pH of the aqueous silicate solution to a neutral to acidic range from the viewpoint of stability. Therefore, the pH of the aqueous silicate solution is 7 or less, preferably 6.5 or less, and more preferably 6 or less. On the other hand, the lower limit of the pH of the aqueous silicate solution is not particularly limited, but is, for example, 1 or more. The pH adjuster is not particularly limited, and hydrochloric acid, nitric acid, phosphoric acid, sulfuric acid, or a carboxylic acid such as acetic acid can be used, but in consideration of volatility and corrosiveness to the base material, acetic acid is desirable.

The tetraalkyl silicate or its oligomer contained in the aqueous silicate solution is preferably a tetraalkyl silicate or its oligomer that does not produce by-products that may cause corrosion of the film or deterioration of the adhesive resin after the reaction. From this viewpoint, for example, tetramethyl orthosilicate, tetraethyl orthosilicate, tetraisopropyl orthosilicate or the like, or an oligomer thereof is preferable, and among them, from the viewpoint of economy and safety, tetraethyl orthosilicate or an oligomer thereof is preferable. Here, as the tetraalkyl silicate or the oligomer thereof, only one kind may be used alone, or two or more kinds may be used in combination.

Further, it is preferable that the silicate aqueous solution does not substantially contain a particulate inorganic compound having a diameter of 1 nm or more (particulate inorganic compound). Examples of the particulate inorganic compound include inorganic oxide sols such as silica and alumina. A particulate inorganic compound such as silica is generally used for densification of a tetraalkyl silicate film and for making the film thickness uniform, but the resulting film becomes thick. On the other hand, in the present invention, since a thin film is formed, it is not desirable to use silica sol or the like which exerts such an effect. In addition, "the aqueous solution of silicate substantially does not include the particulate inorganic compound" is not limited to an embodiment that does not include the particulate inorganic compound at all, and it is acceptable to include the particulate inorganic compound at an impurity level. To be done. Specifically, it is permissible for the aqueous silicate solution to contain the particulate inorganic compound up to 0.05% by mass or less.

In addition to the tetraalkyl silicate or its oligomer, the aqueous silicate solution may further contain one or more stabilizers, auxiliary agents, etc., if desired. For example, the stabilizer may contain a carboxylic acid having 1 to 4 carbon atoms such as formic acid and acetic acid, an organic compound such as alcohol having 1 to 4 carbon atoms such as methanol and ethanol, and the like.

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

Further, it is preferable not to wash with water (rinse) after treating the oxide film with the aqueous silicate solution. When washing with water (rinsing) is performed, unreacted silicate remaining on the surface of the film is removed, so that a dense film may not be obtained.

After the treatment with the aqueous silicate solution, the aqueous silicate solution is dried. The drying temperature is preferably 70°C or higher, more preferably 80°C or higher, even more preferably 90°C or higher. Further, if the drying temperature is too high, the characteristics of the aluminum alloy are affected, so that 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. The drying time is preferably 20 minutes or less, more preferably 5 minutes or less, and further preferably 2 minutes or less.

The coating amount of the aqueous silicate solution is 1 mg/m ² or more and 20 mg/m ² or less from the viewpoint of forming a film having the above-mentioned FT-IR spectrum and obtaining a sufficient effect of improving the adhesion durability. It is preferable to adjust so that Further, the amount of the film after drying is adjusted to more preferably 1.5 mg/m ² or more and 15 mg/m ² or less, and further preferably 2 mg/m ² or more and 10 mg/m ² or less. If the coating amount of the silicate aqueous solution is too small, the amount of the tetraalkyl silicate or its oligomer may be too small, and good adhesion durability may not be obtained. Further, if the coating amount of the silicate aqueous solution becomes too large, the formed film becomes too thick and peeling may occur in the film, resulting in deterioration of the adhesion durability.

Although the silicate treatment step is performed after the etching step in the film forming step of step S1 described above, these steps may be performed once. Specifically, for example, the oxide film may be treated with a neutral or acidic aqueous solution containing tetraalkyl silicate or an oligomer thereof.

<Other processes>
In the method for manufacturing the aluminum alloy material 10 of the present embodiment, other steps may be included between or before and after each step as long as the above-mentioned steps are not adversely affected. For example, a preliminary aging treatment step of performing a preliminary aging treatment may be provided after the film forming step S2. This preliminary aging treatment is preferably performed by heating at a low temperature of 40 to 120° C. for 8 to 36 hours within 72 hours. By performing the pre-aging treatment under this condition, the formability and the strength after baking can be improved. In addition, for example, a foreign matter removing step of removing foreign matter on the surface of the aluminum alloy material 10 and a defective article removing step of removing defective articles generated in each step may be performed.

Then, the manufactured aluminum alloy material 10 may be coated with the press oil on the surface thereof before the production of the bonded body or the processing into the automobile member. 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 the method and conditions for applying a normal press oil can be widely applied. For example, a press containing ethyl oleate as an ester component. The aluminum alloy material 10 may be immersed in oil. The ester component is not limited to ethyl oleate, and various compounds such as butyl stearate and sorbitan monostearate can be used.

As described above in detail, according to the method for producing an aluminum alloy material of the present embodiment, a film that gives high adhesion durability without performing treatment such as washing with water after treatment with an aqueous silicate solution and treatment with a silane coupling agent. Therefore, the whole process can be downsized, 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, the press oil may be applied to the surface of the aluminum alloy material, but in the present specification, when the adhesive resin is bonded to the aluminum alloy material applied with the press oil and used. Also, it is included in using the adhesive resin directly bonded to the film of the aluminum alloy material.

(Modification of the first embodiment)
Next, an aluminum alloy material with an adhesive resin layer according to a modified example of the first embodiment of the present invention will be described. FIG. 3 is a cross-sectional view schematically showing the configuration of the aluminum alloy material with an adhesive resin layer of this modification. In FIG. 3, the same components as those of the aluminum alloy material 10 shown in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted. As shown in FIG. 3, in the aluminum alloy material 11 with an adhesive resin layer of this modification, the adhesive resin layer 4 is directly formed so as to cover the film 2 in 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 an 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 having a film formed thereon like the aluminum alloy material 11 with an adhesive resin layer, an aluminum alloy material having no oxide film formed thereon, a resin molded body, and the like. ..

The adhesive resin that constitutes the adhesive resin layer 4 is not particularly limited, and is conventionally used when joining aluminum alloy materials such as epoxy resin, urethane resin, nitrile resin, nylon resin, and acrylic resin. Adhesive resins that have been used can be used. Of these, epoxy resins are preferable from the viewpoint of adhesive strength. Further, the adhesive resin may be used alone or in combination of two or more.

Although the type of the coupling agent is not particularly limited, for example, the thickness of the adhesive resin layer 4 is also 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, when the aluminum alloy material 11 with an adhesive resin layer and an aluminum alloy material not provided with another adhesive resin layer are bonded 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 the organic-inorganic coupling agent contained in the adhesive resin layer 4 (adhesive resin) is not particularly limited, but examples thereof include a silane coupling agent, a titanate coupling agent, an aluminate coupling agent, and a phosphate cup. A ring agent or the like can be used. As the silane coupling agent, at least one functional group such as a vinyl group, a styryl group, an acryl group, a methacryl group, an epoxy group, an amino group, a ureido group, a mercapto group, or an isocyanate group, which has high reactivity with an adhesive resin. It is preferable to use the silane coupling agent having the above. Preferable specific examples of the functional group contained in the silane coupling agent include, for example, an epoxy group, an amino group, and a ureido group. Here, as the organic-inorganic coupling agent, one type may be used alone, or two or more types may be used in combination.

[Production method]
Next, a method for manufacturing the aluminum alloy material 11 with the adhesive resin layer of this modification will be described. FIG. 4 is a flowchart showing a method for 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 the present modification, an adhesive resin layer forming step S3 is performed in addition to steps S1 and 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, heat is applied for pressure bonding, or this is dissolved in a solvent to form 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.

Further, also in the aluminum alloy material 11 with an adhesive resin layer of the present modified example, as in the first embodiment described above, a preliminary aging treatment is performed after the film forming step S2 and/or the adhesive resin layer forming step S3. An aging treatment step may be provided.

In the aluminum alloy material with the 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 manufacturing the joined body or the automobile member. can do. The configurations and effects of the aluminum alloy material with the adhesive resin layer of the present modification other than the above are the same as those of the first embodiment described above.

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

[Structure of bonded body]
In the joined body of the present embodiment, for example, like the joined body 20 shown in FIG. 5, 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. It is also possible to adopt a configuration in which they are joined via the adhesive resin 5. That is, in the bonded body 20, one surface of the adhesive resin 5 is bonded to the coating 2 side of the aluminum alloy material 10 on one side, and the other surface is bonded to the coating 2 side of the aluminum alloy material 10 on the other side.

Here, as the adhesive resin 5 in the bonded body of the present embodiment, the same adhesive resin as the above-mentioned adhesive resin forming the adhesive resin layer 4 can be used. Specifically, the adhesive resin 5 may be an epoxy resin, a urethane resin, a nitrile resin, a nylon resin, an acrylic resin, or the like. 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 joined body 20, since both surfaces of the adhesive resin 5 are the coatings 2 of the aluminum alloy material 10 of the first embodiment, when used as an automobile member, even when exposed to a high temperature and humid environment. The adhesive strength at the interface between the adhesive resin 5 and the film 2 is less likely to decrease, and the adhesive durability is improved. In addition, in the joined body 20 of the present embodiment, the adhesive durability at the interface is improved in all adhesive resins conventionally used for joining aluminum alloy materials regardless of the type of the adhesive resin 5.

Moreover, like the bonded body 21a shown in FIG. 6A or the bonded body 21b shown in FIG. 6B, the coating 2 is formed on the surface of the aluminum alloy material 10 shown in FIG. It is also possible to adopt a configuration in which another aluminum alloy material 6 or resin molded body 7 that is not formed is joined.

Here, as the other aluminum alloy material 6 on which the film 2 is not formed, the same material as the above-mentioned base material 3 can be used, and specifically, it is specified in JIS or close to JIS. A variety of non-heat treated or heat treated 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 ( Fiber reinforced plastic moldings formed of various fiber reinforced plastics such as DFRP) and Zylon reinforced plastic (ZFRP) can be used. By using these fiber-reinforced plastic molded products, it becomes possible to reduce the weight of the bonded product while maintaining a constant strength.

In addition to the fiber reinforced plastics described above, the resin molded body 7 includes polypropylene (PP), acrylic-butadiene-styrene copolymer (ABS) resin, polyurethane (PU), polyethylene (PE), polyvinyl chloride (PVC). Fiber reinforced with nylon, nylon 6, nylon 6,6, polystyrene (PS), polyethylene terephthalate (PET), polyamide (PA), polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), polyphthalamide (PPA), etc. It is also possible to use no resin.

In the joined bodies 21a and 21b shown in FIGS. 6A and 6B, since one surface of the adhesive resin 5 is joined to the coating 2 side of the aluminum alloy material 10, the joined body 21 was used for a vehicle member similarly to the joined body 20 described above. At this time, even if it is exposed to a high temperature and wet environment, it is not affected by the type of the adhesive resin, and the adhesive durability at the interface is improved. Further, since the joined body 21b shown in FIG. 6B joins the aluminum alloy material 10 and the resin molded body 7, it is lighter in weight than the joined body of aluminum alloy materials, and by using this joined body 21b. Further weight reduction of the automobile can be realized. The configurations and effects of the bonded bodies 21a and 21b shown in FIGS. 6A and 6B other than the above are the same as those of the bonded body 20 shown in FIG.

Further, like the bonded body 22 shown in FIG. 7, the aluminum alloy material 11 with the adhesive resin layer 4 shown in FIG. 3 and the aluminum alloy material 10 not having the adhesive resin layer 4 shown in FIG. It is also possible to adopt a configuration in which and are joined. Specifically, the coating resin 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 so as to face each other via the adhesive resin layer 4 of the aluminum alloy material 11 with the adhesive resin layer. It is composed.

In the bonded body 22, since both surfaces of the adhesive resin layer 4 are bonded to the coating 2 of the aluminum alloy material 10 and the coating 2 of the aluminum alloy material 11 with the adhesive resin layer, respectively, as in the bonded body 20 described above. When 22 is used as a member for automobiles, even if it is exposed to a high temperature and humid environment, it is not affected by the type of adhesive resin, and the adhesive durability at the interface is improved. The configuration and effects of the bonded body 22 shown in FIG. 7 other than the above are the same as those of the bonded body 20 shown in FIG.

Further, like the bonded body 23a shown in FIG. 8A or the bonded 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 an adhesive resin layer having the adhesive resin layer 4 shown in FIG. It is also possible to adopt a configuration in which another aluminum alloy material 6 in which the resin is not formed or a resin molded body 7 such as a fiber reinforced plastic molded body is joined. In these bonded bodies 23a and 23b, one surface of the adhesive resin layer 4 is bonded to the film 2 side of the aluminum alloy material 11 with the adhesive resin layer. Therefore, as with the bonded body 20 described above, the bonded body 23 is bonded to an automobile member. When it is used for, it is not affected by the kind of the adhesive resin even if it is exposed to a high temperature and humid environment, and the adhesion durability at the interface is improved.

Further, since the joined body 23b shown in FIG. 8B joins the aluminum alloy material 11 with the adhesive resin layer and the resin molded body 7, it is lighter than the joined body of aluminum alloy materials, and it is required to reduce the weight. It is suitable for existing automobiles and vehicle members. The configurations and effects of the bonded bodies 23a and 23b shown in FIGS. 8A and 8B other than the above are the same as those of the bonded body 20 shown in FIG.

[Method for manufacturing bonded body]
As a method of manufacturing the above-described 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, but for example, an adhesive sheet prepared in advance with the adhesive resin 5 may be used, or the adhesive resin 5 may be formed on the surface of the film 2. It may also be formed by spraying or applying on. The joined bodies 20 to 23 may be coated with press oil on the surface thereof before being processed into a member for automobiles, like the aluminum alloy material 10 and the aluminum alloy material 11 with an adhesive layer.

Further, although not shown, when an aluminum alloy material having a film formed on both surfaces (with an adhesive resin layer) is used for the joined body of the present embodiment, these (adhesive resin It is possible to further join an aluminum alloy material (with a layer), another aluminum alloy material on which no film is formed, or a resin molded body.

(Third Embodiment)
Next, an automobile member according to a third embodiment of the present invention will be described. The automobile member of the present embodiment uses the joined body of the second embodiment described above, and is, for example, an automobile panel or the like.

The method for manufacturing the automobile member of the present embodiment is not particularly limited, but a conventionally known manufacturing method can be applied. For example, the joined bodies 20 to 23b shown in FIGS. 5 to 8B are subjected to cutting, pressing, or the like to manufacture a vehicle member having a predetermined shape.

Since the automobile member of the present embodiment is manufactured from the bonded body of the second embodiment described above, even if it is exposed to a high temperature wet environment, the influence of hydration of the adhesive resin or the adhesive resin layer and the film is almost eliminated. It is also possible to suppress the elution of the aluminum alloy base material without receiving it. As a result, in the automobile member of the present embodiment, it is possible to suppress interfacial peeling when exposed to a high temperature and humid environment and suppress a decrease in adhesive strength.

Hereinafter, the effects of the present invention will be specifically described with reference to Examples and Comparative Examples of the present invention. In this example, an aluminum alloy material was produced by the method and conditions shown below, and its adhesion durability and the like were evaluated.

<Example 1>
A 6000 series aluminum alloy of JIS6016 (Mg: 0.54% by mass, Si: 1.11% by mass, Cu: 0.14% by mass) was used to produce an aluminum alloy cold-rolled plate having a plate thickness of 1 mm. Then, this cold-rolled sheet was cut into a length of 100 mm and a width of 25 mm to obtain a base material, which was subjected to heat treatment up to an actual temperature of 550° C. and cooled. Subsequently, the substrate was degreased with an aqueous solution of pH 13 containing potassium hydroxide at 50° C. for 40 seconds, and further pickled with a solution of pH 1 containing sulfuric acid and hydrofluoric acid at a temperature of 50° C. for a treatment time of 40 seconds. After that, an aqueous solution containing 0.026 mass% of tetraethyl orthosilicate (hereinafter, also referred to as TEOS) (hereinafter, also referred to as TEOS aqueous solution) was uniformly applied to the surface with a bar coater. Then, it was heated and dried at 100° C. for 1 minute to obtain an aluminum alloy material of Example 1 having a film 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 TEOS concentration in the TEOS aqueous solution was 0.065% by mass.

<Example 3>
An aluminum alloy material of Example 3 was obtained in the same manner as in Example 1 except that the TEOS concentration in the TEOS aqueous solution was 0.13% by mass.

<Example 4>
An aluminum alloy material of Example 4 was obtained in the same manner as in Example 1 except that the TEOS concentration in the TEOS aqueous solution was 0.325% by mass.

<Example 5>
An aluminum alloy material of Example 5 was obtained in the same manner as in Example 1 except that TEOS in the TEOS aqueous solution was an oligomer (degree of polymerization: 10 to 20) and the concentration thereof was 0.25% by mass.

<Example 6>
An aluminum alloy material of Example 5 was obtained in the same manner as in Example 1 except that the TEOS concentration in the TEOS aqueous solution was 0.325 mass% and the base material was washed with water after coating.

<Comparative Example 1>
An aluminum alloy material of Comparative Example 1 was obtained in the same manner as in Example 1 except that the TEOS concentration in the TEOS aqueous solution was 2.5% 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 TEOS concentration in the TEOS aqueous solution was 0.013% 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 TEOS concentration in the TEOS aqueous solution was 0.13% and that the silica sol having a particle diameter of 5 nm was 0.1% by mass.

<Comparative example 4>
An aluminum alloy material of Comparative Example 4 was obtained in the same manner as in Example 1 except that the TEOS concentration in the TEOS aqueous solution was set to 0.065 mass% without performing alkali degreasing and pickling.

<Comparative Example 5>
An aluminum alloy material of Comparative Example 5 was obtained in the same manner as in Example 1 except that the pickling time was 300 seconds and the TEOS concentration in the TEOS aqueous solution was 0.13%.

(IR spectrum measurement)
About the aluminum alloy material which has a film on the surface and which concerns on each Example and a comparative example, FT-IR(Fourier transform infrared spectrophotometer: Nicona Magna-750 spectrometer) is used using the parallel polarization of incident angle 75 degree. ) An IR spectrum was measured by analysis, and an absorption band existing in a wave number range of 1000 to 1300 cm ⁻¹ was read in the difference spectrum before and after the film treatment. Table 1 shows the maximum points of absorption in each absorption band.

(Measurement of element concentration of film components)
The element component concentration in the film was measured by high frequency glow discharge optical emission spectroscopy (GD-OES: Horiba Jobin Yvon Co., Ltd. model JY-5000RF) while sputtering in the film thickness direction, and aluminum (Al), magnesium (Mg) ), copper (Cu), iron (Fe), titanium (Ti), and other metal elements, and oxygen (O), nitrogen (N), carbon (C), silicon (Si), sulfur (S), and other elements The amount of each component was measured. For magnesium (Mg), copper (Cu), and silicon (Si), the maximum concentration in the coating was defined as the coating concentration in the coating. Regarding aluminum (Al), since the base material is affected in the vicinity of the interface between the base material and the film, the concentration of the outermost surface is defined as the film concentration of aluminum (Al). Here, in the calculation of the concentration of each 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 likely to be affected by contamination on the outermost surface and in the vicinity thereof, and it is difficult to measure an accurate concentration, but the film of all samples contains 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 by fluorescent X-ray, the intensity of the fluorescent X-ray and the amount of film are converted using a calibration curve, and the amount of silicon contained in the substrate is subtracted. did. The results are shown in Table 1.

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

<Cohesive failure rate (adhesion durability)>
9A and 9B are diagrams schematically showing a method for 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 in a wrap length of 10 mm (bonding area: 25 mm×10 mm). ) Was pasted and pasted.
The adhesive resin 35 used here is a thermosetting epoxy resin-based adhesive resin (bisphenol A type epoxy resin amount 40 to 50% by mass). Further, a small amount of glass beads (particle size 250 μm) was added to the adhesive resin 35 to adjust the thickness of the adhesive resin 35 to 250 μm.
After overlapping, 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 produced adhesion test body was immersed in an aqueous sodium chloride solution having a concentration of 5% at 40° C. for 20 days, and then pulled at a speed of 50 mm/min with a tensile tester to evaluate the cohesive failure rate of the adhesive resin in the bonded portion. The cohesive failure rate was calculated based on the following mathematical formula 1. In the following numerical formula 1, one side of the adhesion test body after being pulled was designated as a test piece a and the other side was designated as a test piece b.

Three pieces were produced under each test condition, and the cohesive failure rate was an average value of the three pieces. The evaluation criteria are that the cohesive failure rate is less than 60% as poor (x), 60% or more and less than 70% as somewhat good (Δ), 70% or more and less than 90% as good (◯), and 90% or more as excellent. (◎). 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 was higher than the range specified in the present invention, and the adhesion durability was poor.
In the aluminum alloy material of Comparative Example 2, the Si concentration in the film was lower than the range specified in the present invention, and one of the absorption bands was outside the wave number range specified in the present invention, and the adhesion durability was improved. I was scarce.
Further, in the aluminum alloy material of Comparative Example 3, one of the absorption bands was out of the wave number range specified in the present invention, and the adhesion durability was poor.
Further, the aluminum alloy material of Comparative Example 4 had a Mg concentration in the film higher than the range specified in the present invention, and was poor in adhesion durability.
Further, the aluminum alloy material of Comparative Example 5 had a Cu concentration in the coating higher than the range specified in the present invention, and was poor in adhesion durability.

On the other hand, the aluminum alloy materials of Examples 1 to 6 satisfying the requirements specified in the present invention had good wet durability in a high temperature and high humidity environment.

2 Film 3 Base material 4 Adhesive resin layer 5, 35 Adhesive resin 6, 10 Aluminum alloy material 11 Aluminum alloy material with adhesive resin layer 7 Resin molded body 20, 21a, 21b, 22, 23a, 23b Bonded body 31a, 31b Test sample Material

Claims (12)

Aluminum alloy base material,
An aluminum alloy material formed on at least a part of the surface of the aluminum alloy substrate, comprising an aluminum oxide film containing silicon,
The film has two absorption bands in the wave number range of 1000 to 1300 cm ⁻¹ in the difference spectrum before and after the film treatment, which is obtained by injecting parallel polarized light with an incident angle of 75° by Fourier transform infrared spectroscopy. The two absorption bands are in the ranges of wave numbers of 1080 to 1140 cm ⁻¹ and wave numbers of 1180 to 1240 cm ⁻¹ , and the film has Si of 20 atomic% or more and less than 70 atomic% and Mg of 0.1 atomic% or more of 30 atomic% or more. An aluminum alloy material containing less than atomic% and Cu regulated to less than 0.6 atomic %. The aluminum alloy material according to claim 1, wherein the coating does not substantially include a particulate inorganic compound having a diameter of 1 nm or more. 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 any one of claims 1 to 3. 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 or 5, wherein the adhesive resin layer contains 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 through an adhesive resin. A joined body obtained by joining the aluminum alloy material with an adhesive resin layer according to any one of claims 4 to 6 to another member 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 the surface of an aluminum alloy substrate,
The film forming step includes a heat treatment step of forming an oxide film on the surface of the aluminum alloy base material, an etching treatment step and a silicate treatment step after the heat treatment step, and the silicate treatment step is the etching treatment step. Later or at the same time as the etching step,
The method for producing an aluminum alloy material, wherein, as the silicate treatment step, the oxide film is treated with an aqueous solution containing 0.02% by mass to 2% by mass of a tetraalkyl silicate or an oligomer thereof. The method for manufacturing an aluminum alloy material according to claim 9, wherein washing with water is not performed after the treatment with the aqueous solution. The method for producing an aluminum alloy material according to claim 9 or 10, wherein the aqueous solution does not substantially contain a particulate inorganic compound having a diameter of 1 nm or more. The method for manufacturing an aluminum alloy material according to claim 9, wherein the etching amount in the etching step is controlled to be less than 700 nm.