WO2017006804A1 - Aluminum alloy manufacturing method, aluminum alloy, and conjugate - Google Patents

Abstract

The present invention relates to an aluminum alloy manufacturing method provided with: an oxide coating formation step for forming an oxide coating, which contains 0.1 atom% to less than 30 atom% of Mg and in which Cu is restricted to less than 0.6 atom%, on at least a portion of the surface of an aluminum alloy base material; and a treated surface coating formation step comprising the coating of an aqueous solution, which contains 0.001 mass% to less than 0.5 mass% of a silicic acid salt and 0.001 mass% to less than 0.5 mass% of an organic silane compound and the pH of which is 7 to 14, on at least a portion of said oxide coating. With this aluminum alloy manufacturing method, it is possible to manufacture an aluminum alloy that is not susceptible to reduction of adhesive strength even when exposed to a hot and humid environment, has excellent adhesion durability, and can be produced efficiently.

Description

Method for producing aluminum alloy material, aluminum alloy material, and joined body

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

Various aluminum alloy sheet materials are appropriately selected and used for members of transport equipment such as automobiles, ships, and airplanes according to their characteristics. In recent years, in consideration of global environmental problems such as CO ₂ emission suppression, there has been a demand for improvement in fuel efficiency by reducing the weight of members, the specific gravity is about 1/3 that of iron, and excellent energy absorption. The use of aluminum alloy materials is increasing.

For example, JIS5000-based Al—Mg-based alloy materials, JIS6000-based Al—Mg—Si-based alloy plates, and JIS7000-based Al—Zn—Mg-based alloy materials are used for automobile members. It has been. As a joining method of these aluminum alloy materials, there are welding and adhesion by an adhesive, and these methods may be used in combination. Whereas welding joins an aluminum alloy material with dots or lines, bonding with an adhesive bonds the aluminum alloy material over the entire surface, which is advantageous in terms of high joint strength and impact safety. For this reason, in recent years, adhesion by an adhesive tends to increase in automobile members. In some cases, a composite of an aluminum alloy material and a resin is used to reduce the weight of an automobile.

On the other hand, an aluminum alloy automobile member joined with an adhesive gradually deteriorates in the interface between the adhesive layer and the aluminum alloy plate when moisture, oxygen, chloride ions, etc. enter the joint during use. There is a problem that peeling occurs and the adhesive strength decreases. Therefore, conventionally, a method for preventing such a decrease in adhesive strength and improving the adhesion durability of an aluminum alloy automobile member having an adhesive layer has been studied (see, for example, Patent Documents 1 to 3).

For example, Patent Document 1 proposes a method of removing the Mg concentrated layer on the surface of the aluminum alloy plate by pickling and simultaneously concentrating Cu on the surface of the aluminum alloy plate. Patent Document 2 proposes a method in which the amount of Mg concentrated on the surface of an aluminum alloy plate and the OH absorption rate have a specific relationship. Further, Patent Document 3 proposes a method in which the Mg concentration, Si concentration, and OH concentration in the oxide film surface layer of the aluminum material are set to specific ranges by continuously performing solution treatment and hot water treatment. .

Conventionally, for the purpose of preventing discoloration and thread rust, an aluminum for an automobile and an aluminum alloy material which are treated with an aqueous solution containing a silicate and have a silicon-containing film formed on the surface have also been proposed (see Patent Document 4). . Furthermore, a surface treatment method using silicate as a specific example of weak etching is proposed as a method for obtaining uniformity of the zinc phosphate film while maintaining excellent formability in Mg-containing aluminum alloy plates for automobile bodies. (See Patent Document 5).

Japanese Unexamined Patent Publication No. 6-256881 Japanese Unexamined Patent Publication No. 2006-200007 Japanese Unexamined Patent Publication No. 2007-217750 Japanese Patent Laid-Open No. 8-144064 Japanese Laid-Open Patent Publication No. 7-188956

However, when the techniques described in Patent Documents 1 to 3 described above are exposed to a high-temperature and humid environment in which moisture, oxygen, chloride ions, and the like permeate, the deterioration of the interface proceeds, and the interface peels off. There is a problem that the strength is lowered or the corrosion of Al is promoted. For example, the technique described in Patent Document 1 describes that the bonding with an adhesive is strengthened by concentration of Cu and the adhesiveness is improved. However, an aluminum alloy plate to which this technique is applied is a resin in a wet environment. Decomposition may be accelerated, and high durability cannot be expected.

Further, even in the techniques described in Patent Documents 4 and 5, the surface treatment using silicate is performed, but only the surface treatment using silicate is a patent document relating to coating, and is not related to adhesion durability. . Therefore, although corrosion resistance important for coating may be obtained, the strength required for adhesion durability is not considered, and the effect of improving adhesion durability cannot be expected.

Accordingly, the present invention provides an aluminum alloy material production method, an aluminum alloy material, which can produce an aluminum alloy material that is less likely to have a reduced adhesive strength even when exposed to a high-temperature and humid environment, has excellent adhesion durability, and excellent productivity. And a joined body using an aluminum alloy material.

The present inventor has conducted extensive experiments to solve the above-described problems, and as a result, has obtained the following knowledge. In the method of pickling, since the base of the aluminum alloy plate and the adhesive layer are bonded by hydrogen bonds, the interface is hydrated and bonding strength (hydrogen bonding) decreases when exposed to a high temperature and wet environment. To do.

In the method of anodizing, the base of the aluminum alloy plate and the adhesive layer are basically bonded by hydrogen bonding, and when exposed to a high temperature and humidity environment where moisture, oxygen, chloride ions, etc. penetrate. , The interface is hydrated and the bond strength decreases. In addition, the method of performing anodization complicates the apparatus and costs equipment, and further requires a long time for film formation, resulting in a reduction in production efficiency. Furthermore, in the method of performing the hot water treatment, since the base of the aluminum alloy plate and the adhesive layer are bonded by hydrogen bonds, when exposed to a high temperature and humid environment, the interface deteriorates due to the hydration of the interface, and the interface peels off. Occurs and the adhesive strength decreases.

Therefore, the present inventors examined the bonding state between the substrate surface and the adhesive resin layer, and after forming a film made of an oxide film on the surface of the aluminum alloy substrate, at least a part of this oxide film, It has been found that by applying a specific aqueous solution containing a silicate and an organosilane compound to form a surface treatment film, it is possible to suppress a decrease in adhesive strength when exposed to a high-temperature and humid environment, and the present invention has been achieved.

That is, in the method for producing an aluminum alloy material according to the present invention, at least a part of the surface of the aluminum alloy substrate contains Mg at 0.1 atomic% or more and less than 30 atomic%, and Cu is less than 0.6 atomic%. An oxide film forming step for forming a regulated oxide film, and at least a part of the oxide film, 0.001% by mass or more and less than 0.5% by mass of silicate, and 0.001% by mass or more and 0.5% by mass And a surface treatment film forming step including applying an aqueous solution having an organic silane compound of less than mass% and a pH of 7 or more and 14 or less.

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

In the method for producing an aluminum alloy material of the present invention, the organosilane compound may include a silane compound having a plurality of hydrolyzable trialkoxysilyl groups in the molecule, a hydrolyzate thereof, or a polymer thereof. .

In the method for producing an aluminum alloy material of the present invention, the silicate is a silicate represented by mM ₂ O · nSiO ₂ , wherein M is a monovalent cation, and M ₂ O The ratio n / m of m which is the number of moles of n and n which is the number of moles of SiO ₂ may be 1.5 or more.

In the method for producing an aluminum alloy material of the present invention, M may be sodium ion.

Moreover, in the manufacturing method of the aluminum alloy material of this invention, the said oxide film formation process may include an etching process step, and the etching amount in the said etching process step may be 1.9 g / m < ² > or less.

The aluminum alloy substrate can be formed of, for example, an Al—Mg alloy, an Al—Cu—Mg alloy, an Al—Mg—Si alloy, or an Al—Zn—Mg alloy.

The present invention also includes an aluminum alloy material obtained by the method for producing an aluminum alloy material.

Also, the joined body of the present invention is obtained by joining the aluminum alloy material and another member via an adhesive resin.

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. In addition, according to the present invention, an aluminum alloy substrate on which an oxide film is formed can be simplified by simultaneously performing silicate treatment and organosilane treatment using an aqueous solution containing a silicate and an organosilane compound. With this process, an aluminum alloy material (also referred to as a surface-treated aluminum alloy material) can be manufactured, and capital investment costs and manufacturing costs can be reduced.

FIG. 1 is a flowchart showing a method for producing an aluminum alloy material according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing the configuration of the aluminum alloy material before the surface treatment process in a state where an oxide film is formed on the surface of the aluminum alloy substrate. FIG. 3 is a cross-sectional view schematically showing the configuration of the aluminum alloy material with an adhesive resin layer according to the first embodiment of the present invention. FIG. 4 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. 5 is a flowchart showing a method of manufacturing the aluminum alloy material with an adhesive resin layer shown in FIG. FIG. 6 is a cross-sectional view schematically showing a configuration example of a joined body according to the second embodiment of the present invention. FIG. 7A is a cross-sectional view schematically showing another configuration example of the joined body according to the second embodiment of the present invention. FIG. 7B is a cross-sectional view schematically showing another configuration example of the joined body according to the second embodiment of the present invention. FIG. 8 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 cross-sectional view schematically showing another configuration example of the joined body according to the second embodiment of the present invention. FIG. 9B is a cross-sectional view schematically showing another configuration example of the joined body according to the second embodiment of the present invention. FIG. 10A is a side view schematically showing a method for measuring the cohesive failure rate. FIG. 10B 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 manufacturing method of the aluminum alloy material of this embodiment and the aluminum alloy material obtained by the manufacturing method will be described. In the present specification, the percentage based on mass (% by mass) is the same as the percentage based on weight (% by weight).
In the method for producing an aluminum alloy material according to the present embodiment, Mg is contained in at least a part of the surface of the aluminum alloy base material in an amount of 0.1 atomic percent or more and less than 30 atomic percent, and Cu is restricted to less than 0.6 atomic percent An oxide film forming step for forming the formed oxide film, and at least part of the oxide film, 0.001% by mass or more and less than 0.5% by mass of silicate, 0.001% by mass or more and 0.5% by mass And a surface treatment film forming step including applying an aqueous solution having a pH of 7 or more and 14 or less.
FIG. 1 is a flowchart showing a method for manufacturing an aluminum alloy material 10 of this embodiment. As shown in FIG. 1, when manufacturing the aluminum alloy material 10 of this embodiment, base material preparation process S1, oxide film formation process S2, and surface treatment film formation process S3 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.

[Base material]
The base material (aluminum alloy base material) is made of an aluminum alloy. The type of aluminum alloy that forms the base material is not particularly limited, and various non-heat treatment type or heat treatment type aluminum alloys that are prescribed in JIS or approximate to JIS, depending on the application of the member to be processed. 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-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 of the present embodiment is used for an automobile member, the base material 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.

<Step S2: oxide film forming step>
In the oxide film forming step (step S2), Mg is 0.1 atomic% or more and 30 atomic% in at least a part (that is, part or all) of the surface of the base material manufactured in the base material manufacturing step in step S1. It forms less than, and forms the oxide film by which Cu was controlled to less than 0.6 atomic%. In the present embodiment, the oxide film forming step (step S2) specifically includes, for example, a heat treatment stage in which the base material 3 is heat-treated to form the oxide film 1, and an etching treatment stage after the heat treatment stage. With.

FIG. 2 shows the aluminum alloy material before the surface treatment film forming step in which the oxide film 1 is formed on the surface of the base material 3. In addition, in the aluminum alloy material before the surface treatment film formation process shown in FIG. 2, the oxide film 1 is formed on the entire one surface of the base material 3, but this embodiment is not limited to this. Absent. For example, the oxide film 1 may be formed only on a part of the surface of the substrate 3. Moreover, the oxide film 1 may be formed on both surfaces of the base material 3.

As the heat treatment in the heat treatment stage, the base material 3 is heated to a temperature of, for example, 400 to 580 ° C. to form the oxide film 1 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 1 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, at least one of treatment with an acidic solution (pickling) and treatment with an alkaline solution (alkali washing, alkaline degreasing) is performed on part or all of the surface of the substrate 3. I do. 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 1 and the like, and are not particularly limited. For example, the pH is 4 or less (preferably pH 2 or less), Conditions of a processing temperature of 10 to 80 ° C. and 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 base material 3, the thickness of the oxide film 1, etc., and are not particularly limited. Conditions of 80 ° C. and processing time of 1 to 120 seconds can be applied.

In addition, when performing alkali cleaning, it is preferable to perform pickling after alkali cleaning. Further, only the pickling may be performed without alkali cleaning. That is, in the etching treatment stage, it is preferable that the last stage is pickling. 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.

By carrying out the etching process steps as described above, the Mg content in the oxide film 1 is adjusted to 0.1 atomic% or more and less than 30 atomic%, and the Cu content is regulated to less than 0.6 atomic%. Here, the amount of Mg and the amount of Cu in the oxide film can be adjusted or regulated by appropriately controlling various conditions (treatment time, treatment temperature, concentration of chemical solution, pH, etc.) in pickling and alkali washing. it can.

Moreover, it is preferable that the etching amount in an etching process step is 1.9 g / m < ² > or less. When the etching amount exceeds 1.9 g / m ² , copper concentration occurs on the surface of the base material 3, which may cause deterioration of the adhesive resin in a high temperature wet environment which is a deterioration environment. Further, the etching amount is more preferably 1.5 g / m ² or less, and further preferably 1.3 g / m ² or less. Note that the lower limit of the etching amount is not particularly limited, but is preferably 0.005 g / m ² .

Here, the amount of etching (unit: g / m ² ) in the present specification is the amount of decrease in the weight of the base material before and after the oxide film forming step (unit: g), and this is the surface area (unit) of the base material. : A value calculated by dividing by m ² ).

[Oxide film 1]
According to the present oxide film forming step, at least a part of the surface of the base material 3 contains Mg in an amount of 0.1 atomic% to less than 30 atomic%, and Cu is regulated to less than 0.6 atomic%. Is formed. Hereinafter, the suitable range of each component amount contained in the oxide film 1 will be described.

<Mg content>
The aluminum alloy constituting the base material of the aluminum alloy material usually contains magnesium as an alloy component. When the oxide film 1 which is a composite oxide of aluminum and magnesium is formed on the surface of the base material 3, The magnesium oxide film is present on the surface in a concentrated state. Therefore, in this state, since the magnesium oxide film layer is too thick even if it passes through the surface treatment film forming step that is the next step S3 described later, the surface treatment film 2 described later contains a large amount of magnesium, In the surface treatment film 2 thus formed, the strength of the film itself cannot be obtained, and the initial adhesiveness is lowered.

Also, in a high-temperature and humid environment where moisture, oxygen, chloride ions, etc. penetrate, it causes hydration at the interface with the adhesive resin layer and corrosion of the base material, thereby reducing the adhesion durability of the aluminum alloy material. Specifically, when the Mg content in the oxide film 1 before the surface treatment film formation described later is 30 atomic% or more, the initial adhesiveness and adhesion durability of the aluminum alloy material after the surface treatment film formation is lowered. Tend. Therefore, in the manufacturing method of the aluminum alloy material 10 of the present embodiment, the Mg content in the oxide film 1 before the formation of the surface treatment film is restricted to less than 30 atomic%. Thereby, initial adhesiveness and adhesion durability can be improved. The Mg content of the oxide film 1 before forming the surface treatment film is preferably less than 25 atomic%, more preferably less than 20 atomic%, and even more preferably 10 atomic% from the viewpoint of improving the initial adhesiveness and adhesion durability. Is less than.

On the other hand, in the manufacturing method of the aluminum alloy material 10 of the present embodiment, the lower limit value of the Mg content of the oxide film 1 before the formation of the surface treatment film is 0.1 atomic% or more from the viewpoint of economy. Here, the Mg content in the oxide film 1 before the formation of the surface treatment film can be measured by high-frequency glow discharge emission spectroscopy (GD-OES).

<Cu content>
When excessive etching is performed on the base material 3 by a degreasing process or a pickling process when forming the oxide film 1, Cu contained in the base material 3 is concentrated on the surface, and the Cu content of the oxide film 1 is increased. To increase. If Cu is present on the surface of the oxide film 1, Cu is excessively contained in the surface treatment film 2 formed in the surface treatment film formation step, which is the next step S3 described later, which causes a decrease in adhesion durability. .

Therefore, in the manufacturing method of the aluminum alloy material 10 of the present embodiment, the Cu content in the oxide film 1 before the formation of the surface treatment film is restricted to less than 0.6 atomic%. In addition, as for Cu content in the oxide film 1 before surface treatment film formation, it is more preferable that it is less than 0.5 atomic%.

<Film thickness>
The thickness of the oxide film 1 before the formation of the surface treatment film is preferably 1 to 30 nm. When the film thickness of the oxide film 1 before forming the surface treatment film is less than 1 nm, the oxide film 1 to which the surface treatment liquid used in the surface treatment film formation process reacts is thin, the surface treatment liquid becomes excessive, and the unreacted surface The treatment liquid remains on the substrate, which may cause a decrease in adhesion durability. Even when the surface treatment liquid is not excessive, in order to control the film thickness of the oxide film 1 before forming the surface treatment film to less than 1 nm, excessive acid cleaning is required, so that productivity is inferior and practicality is low. Is prone to decline. Further, excessive etching with 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. Therefore, the etching amount is 1.9 g / m ² or less. It is preferable.

On the other hand, when the film thickness of the oxide film 1 before the surface treatment film formation exceeds 30 nm, the surface treatment liquid used in the surface treatment film formation step is insufficient with respect to the oxide film 1 that reacts and reacts with the oxide film 1. Becomes insufficient, and this may cause a decrease in adhesion durability. Further, the oxide film 1 having a film thickness exceeding 30 nm contains a large amount of magnesium, so that the strength of the film itself is lowered and the initial adhesiveness may be deteriorated. In addition, as for the film thickness of the oxide film 1 before surface treatment film formation, it is more preferable that they are 2 nm or more and less than 20 nm from viewpoints, such as a chemical conversion property and productivity.

<Step S3: Surface treatment film forming step>
In the surface treatment film formation step (step S3), at least a part of the oxide film 1 formed in step 2 has a silicate of 0.001 mass% or more and less than 0.5 mass%, and 0.001 mass% or more. Application of an aqueous solution (surface treatment liquid) having an organic silane compound of less than 0.5% by mass and a pH of 7 or more and 14 or less. By applying the surface treatment liquid to the oxide film 1 formed in the oxide film formation step (step S2) and performing surface treatment, the oxide film 1 reacts with the surface treatment liquid, and at least aluminum (Al), silicon ( A surface treatment film 2 containing Si), oxygen (O), and an organosilane compound is formed on the surface of the substrate 3. However, the oxide film 1 does not become a uniform surface-treated film 2, and the oxide film 1 is modified to a film containing mainly Al and O and containing Si (including Al—O—Si bond). On top, a film mainly containing Si and O (siloxane bond) and containing Al (including Al—O—Si bond) is formed, and the Si concentration decreases from the outermost surface side to the substrate side, Moreover, it becomes a film | membrane which has a structure where Al concentration increases. That is, the Al—Si ratio of the Al—O—Si bond is different in the cross-sectional direction, and the bond between the surface treatment film 2 and the substrate 3 is an Al-rich Al—O—Si bond, and the aluminum alloy substrate And the surface of the surface treatment material (aluminum alloy material after the surface treatment) have Si-rich Al—O—Si bonds. Thereby, corrosion resistance can be improved. It is also possible to form a chemical bond between the organosilane compound and the adhesive resin, which results in better corrosion resistance and strengthens the bond with the adhesive resin. Further, the surface treatment film 2 itself is very thin, and the distribution state in the film thickness direction of the silicate and the organosilane compound is different, but at least a mixed structure is formed, and the surface treatment film 2 is extremely thin. Its strength is also high. In this way, the surface treatment film 2 is formed by performing the surface treatment using the surface treatment liquid containing both the silicate and the organosilane compound, and the surface treatment is performed using only the organosilane compound. In addition, an alloy material with improved adhesion durability can be obtained.

FIG. 3 shows the aluminum alloy material of the present embodiment in which the surface treatment film 2 is formed on the surface of the substrate 3. In the aluminum alloy material shown in FIG. 3, the surface treatment film 2 is formed on the entire one surface of the substrate 3, but the present embodiment is not limited to this. For example, the surface treatment film 2 may be formed on only a part of the surface of the substrate 3. Further, the surface treatment film 2 may be formed on both surfaces of the substrate 3.

Hereinafter, the surface treatment liquid used for forming the surface treatment film will be described.
The surface treatment solution has a pH of 7 or more and 14 or less. When the pH of the surface treatment liquid is higher than 14, most of the organosilane compound is polymerized and precipitated, so that the solution itself becomes an unstable solution. In addition, when the polymerized organic silane compound is bonded to the oxide film on the surface of the aluminum alloy substrate, the resulting organic silane treatment layer becomes thick, and therefore, when stress is applied, the organic silane treatment layer is destroyed inside. . On the other hand, when the pH of the surface treatment solution is lower than 7, silicate precipitates, so that aluminum and silicon cannot react. Therefore, the pH of the surface treatment liquid needs to be in the range of 7 or more and 14 or less. The pH of the surface treatment solution is preferably 8 or more, more preferably 9 or more. The pH of the surface treatment solution can be appropriately adjusted by adding a base such as sodium hydroxide, sodium carbonate, or ammonia, or an acid such as acetic acid.

The concentration of silicate in the surface treatment liquid is 0.001% by mass or more and less than 0.5% by mass. When the concentration of the silicate in the surface treatment liquid is 0.5% by mass or more, the formed film becomes thick and the strength decreases. On the other hand, if the concentration of silicate in the surface treatment liquid is less than 0.001% by mass, the concentration of silicate is too low, so that aluminum and silicon cannot sufficiently react, and sufficient adhesion durability is achieved. Sex cannot be obtained. The concentration of the silicate in the surface treatment liquid is preferably 0.01% by mass or more, and more preferably 0.015% by mass or more. Further, the concentration of silicate in the surface treatment liquid is preferably less than 0.3% by mass, and more preferably less than 0.2% by mass.

Further, the concentration of the organosilane compound in the surface treatment liquid is 0.001% by mass or more and less than 0.5% by mass. When the concentration of the organosilane compound in the surface treatment liquid is 0.5% by mass or more, the generated surface treatment film becomes thick and the strength is lowered. On the other hand, when the concentration of the organic silane compound in the surface treatment liquid is less than 0.001% by mass, the concentration of the organic silane compound is too low, so that a surface treatment film containing the organic silane compound cannot be sufficiently formed. Thus, sufficient adhesion durability cannot be obtained. The concentration of the organosilane compound in the surface treatment liquid is preferably 0.005% by mass or more, and more preferably 0.01% by mass or more. Moreover, the concentration of the organosilane compound in the surface treatment liquid is preferably less than 0.4% by mass, more preferably less than 0.3% by mass.

In the present invention, the type of silicate contained in the surface treatment liquid is not particularly limited, but from the viewpoint of water solubility, for example, basic silicates include silicates of alkali metals such as lithium, sodium, and potassium. Silicates containing monovalent cations (M), such as salts and ammonium silicates (mM ₂ O · nSiO _2, and in the following, the number of moles of M ₂ O and the moles of SiO ₂ And a ratio n / m to n which is a number) is preferable. Here, as M which is a monovalent cation, alkali metal ions such as lithium ion, sodium ion and potassium ion are preferable, and sodium ion is particularly preferable from the viewpoint of economy.
Examples of the silicate represented by mM ₂ O · nSiO ₂ include crystalline sodium orthosilicate (mNa ₂ O · nSiO ₂ : n / m = about 0.5), sodium metasilicate (mNa ₂ O NSiO ₂ : n / m = about 1 or so on, layered sodium silicate (mNa ₂ O.nSiO ₂ : n / m = about 1.5 to 3), or amorphous sodium silicate, or Liquid water glass (JIS No. 1, No. 2, No. 3, mNa ₂ O.nSiO ₂ : n / m = range of about 1.5 to 4) and the like.
Of these, a silicate having an n / m of 1.5 or more is preferable because good adhesion durability is obtained. If the n / m ratio is less than 1.5, the corrosion resistance of the film formed by the reaction between the aqueous solution containing the silicate and the organosilane compound and the aluminum oxide film tends to be slightly lowered, and the adhesion durability may be lowered. There is. Moreover, although the upper limit of n / m ratio is not defined, 4 or less is preferable from the problem on the production of silicate. Specific examples include layered crystal sodium silicate and water glass. In particular, a layered crystal silicate is particularly preferable from the viewpoint of stabilization of operation because a high amount of reaction products with minerals is reduced due to high ion exchange capacity and adhesion to an apparatus or a container is reduced.
Here, as a silicate, only 1 type may be used independently and may be used in combination of 2 or more type.

In the present invention, the type of the organic silane compound contained in the surface treatment liquid is not particularly limited, but the organic silane compound is a silane compound having a plurality of hydrolyzable trialkoxysilyl groups in the molecule, a hydrolyzate thereof, or a polymer thereof. May be included. A silane compound having a plurality of hydrolyzable trialkoxysilyl groups in the molecule not only forms a dense siloxane bond, but also has a high reactivity with a metal oxide and forms a chemically stable film. The wet durability of the film can be further increased. In addition, organosilane-treated films have high mutual solubility with machine oils such as processing oil and press oil and organic compounds such as adhesives, and even if machine oil such as process oil and press oil adheres to the film Since the influence can be mitigated, it also plays a role in preventing a decrease in adhesion durability due to oiling. Although the kind of the silane compound is not particularly limited, from the viewpoint of economy, a silane compound (bissilane compound) having two hydrolyzable trialkoxysilyl groups in the molecule is preferable, and examples thereof include bistrialkoxysilylethane and bistrimethyl. Alkoxysilylbenzene, bistrialkoxysilylpropylamine, bistrialkoxysilylpropylamine, bistrialkoxysilylpropyltetrasulfide, and the like can be used. In particular, bistriethoxysilylethane (BTSE) is preferable from the viewpoint of versatility and economy. Here, as an organosilane compound, only 1 type may be used independently and it may be used in combination of 2 or more type.

In addition, the organic silane compound may include a silane coupling agent having a reactive functional group that can chemically bond with the organic resin component, a hydrolyzate thereof, or a polymer thereof. For example, by using a silane coupling agent having a reactive functional group such as amino group, epoxy group, methacryl group, vinyl group and mercapto group alone or in combination with the above silane compound, between the film and the resin A chemical bond can be formed to further enhance the adhesion durability. In addition, the functional group of a silane coupling agent is not limited to what was mentioned above, The silane coupling agent which has various functional groups can be selected suitably according to the adhesive resin to be used. Specific examples of suitable silane coupling agents include, for example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3- (N-aminoethyl) -aminopropyltrimethoxysilane, 3- (N— Aminoethyl) -aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-methacryloxy Examples thereof include propyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane. Here, as a silane coupling agent, only 1 type may be used independently and it may be used in combination of 2 or more type.

In addition, the surface treatment liquid may further contain one or more of a stabilizer, an auxiliary agent and the like, if desired, in addition to the silicate and the organosilane compound. For example, the stabilizer may include organic compounds such as carboxylic acids having 1 to 4 carbon atoms such as formic acid and acetic acid, and alcohols having 1 to 4 carbon atoms such as methanol and ethanol.

Examples of the method for applying the surface treatment liquid include immersion treatment, spraying, roll coating, bar coating, electrostatic coating, and the like. Moreover, it is better that there is no rinsing after the surface treatment, but in some cases, it may be performed with pure water or the like.

After the surface treatment liquid is applied, the surface treatment liquid is dried by heating as necessary. The heating temperature is preferably 70 ° C. or higher, more preferably 80 ° C. or higher, and still more preferably 90 ° C. or higher. Further, if the heating temperature is too high, the characteristics of the aluminum alloy are affected. Therefore, the heating temperature is preferably 220 ° C. or lower, more preferably 200 ° C. or lower, and further preferably 190 ° C. or lower. The drying time is preferably 2 seconds or more, more preferably 5 seconds or more, and further preferably 10 seconds or more, although it depends on the heating temperature. 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 surface treatment liquid is preferably adjusted so that the coating amount after drying is 0.001 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 0.01 mg / m ² or more and 20 mg / m ² or less. If the coating amount of the surface treatment solution is too small, the amount of silicate or organosilane compound may be too small to obtain good adhesion durability. Moreover, when the coating amount of the surface treatment liquid is too large, the surface treatment film to be formed becomes too thick, peeling may occur in the surface treatment film, and adhesion durability may be impaired. In addition, for example, the surface treatment film is not removed in a degreasing etching process for painting after an automobile assembly process, which may adversely affect paint adhesion or may give a difference in paint paste.

<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, after the surface treatment film forming step S3, a preliminary aging treatment step for performing a preliminary aging treatment may be provided. 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.

Then, the manufactured aluminum alloy material 10 is coated with machine oil such as press oil on the surface thereof before manufacturing 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.

Here, since the aluminum alloy material 10 of this embodiment is provided with the surface treatment film 2 rich in the solubility of machine oil on the outermost surface, the adhesive resin is satisfactorily formed thereon even after the machine oil is applied. Can be joined.

As described above in detail, according to the method for manufacturing the aluminum alloy material 10 of the present embodiment, an aqueous solution containing a silicate and an organosilane compound is used for an aluminum alloy base material on which an oxide film is formed. By performing the acid salt treatment and the organic silane treatment at the same time, it is possible to produce an aluminum alloy material in a simplified process, and it is possible to reduce capital investment costs and production costs. Moreover, since the aluminum alloy material 10 of this embodiment has adjusted Mg amount in the oxide film 1 before a surface treatment film formation process to the specific range, it can suppress the elution of the base material 3 and the base material accompanying it 3 can suppress the brittleness caused by the magnesium oxide on the surface of the resin 3 and suppress the deterioration of the adhesive resin. Furthermore, since the amount of Cu in the oxide film 1 before the surface treatment film forming step is regulated to be less than a specific amount, the adhesion durability between the surface treatment film 2 formed by subjecting the oxide film 1 to the surface treatment and the adhesive resin. Improves. As a result, even when the aluminum alloy material 10 of the present embodiment is exposed to a high-temperature and humid environment, the interfacial peeling is suppressed, and a decrease in adhesive strength can be suppressed over a long period of time. Further, the adhesion durability can be improved as compared with the surface treatment using only the organosilane compound.

(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. 4 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. 4, the same components as those of the aluminum alloy material 10 shown in FIG. 3 are denoted by the same reference numerals, and detailed description thereof is omitted. As shown in FIG. 4, the aluminum alloy material 11 with an adhesive resin layer of the present modification is an adhesive resin layer 4 made of an adhesive resin so as to cover the surface treatment film 2 in the aluminum alloy material of the first embodiment described above. Is formed.

[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 this modification is joined to another member via the adhesive resin layer 4. In addition, as for the other members, as with the aluminum alloy material 11 with the adhesive resin layer, another aluminum alloy material on which a surface treatment film is formed, an aluminum alloy material on which an oxide film and a surface treatment film are not formed, resin molding Body and the like are included.

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.

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.

[Production method]
Next, the manufacturing method of the aluminum alloy material 11 with the adhesive resin layer of this modification is demonstrated. FIG. 5 is a flowchart showing a method for manufacturing the aluminum alloy material 11 with an adhesive resin layer according to this modification. As shown in FIG. 5, when manufacturing the aluminum alloy material 11 with the adhesive resin layer of this modification, an adhesive resin layer forming step S4 is performed in addition to the above-described steps S1 to S3.

[Step S4: Adhesive resin layer forming step]
In the adhesive resin layer forming step S4, the adhesive resin layer 4 made of an adhesive or the like is formed so as to cover the surface treatment 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 surface treatment 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 oxide film forming step S2, the surface treatment film forming step S3, and / or the adhesive resin layer forming step S4 are performed as in the first embodiment. A preliminary aging treatment step for performing preliminary aging treatment may be provided later.

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. 6 to 9B are cross-sectional views schematically showing a configuration example of the joined body of this embodiment. 6 to 9B, the same components as those of the aluminum alloy material 10 and the aluminum alloy material 11 with the adhesive resin layer 11 shown in FIGS. 3 and 4 are denoted by the same reference numerals, and detailed description thereof is omitted.

[Composition structure]
In the joined body of this embodiment, for example, as in the joined body 20 shown in FIG. 6, the two aluminum alloy materials 10 shown in FIG. 3 are arranged so that the surfaces on which the surface treatment film 2 is formed face each other. It can be set as the structure arrange | positioned and joined via the adhesive resin 5. FIG. That is, in the bonded body 20, one surface of the adhesive resin 5 is bonded to the surface treatment film 2 side of one aluminum alloy material 10, and the other surface is bonded to the surface treatment 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.

In the joined body 20, as described above, both surfaces of the adhesive resin 5 are the surface treatment film 2 of the aluminum alloy material 10 of the first embodiment. However, the adhesive strength at the interface between the adhesive resin 5 and the surface treatment film 2 is hardly 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.

Further, like the bonded body 21a shown in FIG. 7A or the bonded body 21b shown in FIG. 7B, the surface where the surface treatment film 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 in which the membrane | film | coat and the surface treatment membrane | film | coat are not formed.

Here, as the other aluminum alloy material 6 on which the oxide film and the surface treatment film are not formed, the same material as the base material 3 described above can be used, and specifically, as defined in JIS or Those made of various non-heat treatment type or heat treatment type aluminum alloys similar to JIS 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 FIGS. 7A and 7B, since one surface of the adhesive resin 5 is joined to the surface treatment film 2 side, when used for a member for an automobile as in the above-described joined body 20, the temperature is high. Even when exposed to a 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 21b shown to FIG. 7B 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. 7A and 7B are the same as those of the joined body 20 shown in FIG.

Furthermore, like the joined body 22 shown in FIG. 8, the aluminum alloy material 11 with the adhesive resin layer provided with the adhesive resin layer 4 shown in FIG. 4 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 surface treatment film 2 of the aluminum alloy material 10 is bonded 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, since both surfaces of the adhesive resin layer 4 are joined to the surface treatment film 2 side, as in the joined body 20 described above, when the joined body 22 is used as a member for an automobile, a high temperature and humid environment is created. Even if exposed, the adhesion durability at the interface is improved without being influenced by the type of the adhesive resin. The configuration and effects of the joined body 22 shown in FIG. 8 other than those described above are the same as those of the joined body 20 shown in FIG.

Further, as in the bonded body 23a shown in FIG. 9A or the bonded body 23b shown in FIG. 9B, the surface treatment is performed 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. Another aluminum alloy material 6 on which a film is not formed or a resin molded body 7 such as a fiber reinforced plastic molded body may be joined. In these joined bodies 23a and 23b, since one surface of the adhesive resin layer 4 is joined to the surface treatment film 2 side, when the joined body 23 is used as a member for an automobile as in the above-described joined body 20, a high-temperature wet environment is used. Even if it is exposed to, the durability of adhesion at the interface is improved without being affected by the type of adhesive resin.

Moreover, since the joined body 23b shown to FIG. 9B has joined the aluminum alloy material 11 with an adhesive resin 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. In addition, the structure and effect other than the above in the joined bodies 23a and 23b shown in FIGS. 9A and 9B 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 used as the surface treatment film 2. You may form by spraying or apply | coating to the surface of this. The joined bodies 20 to 23 may be coated with a machine oil such as press oil on the surface thereof before being processed into a member for an automobile, like the aluminum alloy material 10 and the aluminum alloy material 11 with an adhesive resin layer. .

Although not shown, when the aluminum alloy material having the surface treatment film 2 formed on both sides is used for the joined body of the present embodiment, these aluminum alloy materials or the adhesive resin 5 or the adhesive resin layer 4 are used. It becomes possible to further join another aluminum alloy material 6 or resin molded body 7 on which the film 2 is not formed.

(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. 6 to 9B are cut or pressed to produce a predetermined-shaped automobile member.

Since the automobile member according to the present embodiment is manufactured from the joined body according to the second embodiment described above, even if it is exposed to a high temperature and wet environment, the influence of the hydration of the adhesive resin or the adhesive resin layer and the oxide film is affected. Almost no elution of the aluminum alloy base material can be suppressed with little. 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.

(Base material production process and oxide film formation process)
The production of the base material and the formation of the oxide film were performed as follows.

<Examples 1 and 2>
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 is produced by the method described above. did. And this cold-rolled board was cut | disconnected to length 100mm and width 25mm, it was set as the base material, and it heat-processed to the substance ultimate temperature 550 degreeC, and cooled.
Subsequently, the substrate was treated with a solution containing potassium hydroxide adjusted to pH 13 at a temperature of 50 ° C. for a treatment time of 1 to 120 seconds, and then washed with water.
Thereafter, using a solution containing nitric acid adjusted to pH 1, the nitric acid solution treatment was performed under the conditions of a temperature of 40 ° C. and a treatment time of 1 to 120 seconds, and then washed with water to obtain the etching amounts shown in Table 1. As described in 1, an oxide film in which the amount of Mg and the amount of Cu were controlled was formed.

<Examples 3 to 5>
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 is produced by the method described above. did. And this cold-rolled board was cut | disconnected to length 100mm and width 25mm, it was set as the base material, and it heat-processed to the substance ultimate temperature 550 degreeC, and cooled.
Subsequently, the substrate was treated with a solution containing potassium hydroxide adjusted to pH 13 at a temperature of 50 ° C. for a treatment time of 1 to 120 seconds, and then washed with water.
Thereafter, using a solution containing sulfuric acid and hydrofluoric acid adjusted to pH 1, the sulfuric acid / hydrofluoric acid solution treatment was performed under the conditions of a temperature of 50 ° C. and a treatment time of 1 to 120 seconds, and then washed with water. An oxide film was formed in which the etching amount was as described and the Mg amount and Cu amount were controlled as shown in Table 1.

<Examples 6 to 7>
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 is produced by the method described above. did. And this cold-rolled board was cut | disconnected to length 100mm and width 25mm, it was set as the base material, and it heat-processed to the substance ultimate temperature 550 degreeC, and cooled.
Subsequently, the substrate was treated with a sulfuric acid solution under conditions of a temperature of 60 ° C. and a treatment time of 1 to 120 seconds using a solution containing sulfuric acid adjusted to pH 1, and then washed with water to obtain the etching amount shown in Table 1 In addition, as shown in Table 1, an oxide film in which the amount of Mg and the amount of Cu were controlled was formed.

<Examples 8 to 9>
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 is produced by the method described above. did. And this cold-rolled board was cut | disconnected to length 100mm and width 25mm, it was set as the base material, and it heat-processed to the substance ultimate temperature 550 degreeC, and cooled.
Subsequently, using a solution containing nitric acid adjusted to pH 3 on the substrate, the nitric acid solution treatment was performed under the conditions of a temperature of 50 ° C. and a treatment time of 1 to 60 seconds, and then washed with water. In addition, as shown in Table 1, an oxide film in which the amount of Mg and the amount of Cu were controlled was formed.

<Comparative Example 1>
Etching amount shown in Table 1 except that the treatment time of the potassium hydroxide solution was 150 seconds and the treatment time of the solution containing sulfuric acid and hydrofluoric acid was 150 seconds, under the same conditions as in Examples 3-5. In addition, as shown in Table 1, an oxide film in which the amount of Mg and the amount of Cu were controlled was formed.

<Comparative Example 2>
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 is produced by the method described above. did. And this cold-rolled board was cut | disconnected to length 100mm and width 25mm, it was set as the base material, and it heat-processed to the substance ultimate temperature 550 degreeC, and cooled. Here, in Comparative Example 2, the obtained base material was not subjected to alkali degreasing or pickling.

(Surface treatment film formation process)
Next, 0.1% by mass of crystalline layered sodium silicate (SiO ₂₎ was added to the oxide film on the surface of the aluminum alloy substrate on which the oxide film was formed, obtained in Examples 1 to 9 and Comparative Examples 1 and _2. and Na ₂ O molar ratio of about 2) (and Tokuyama Siltech made pre feed), and a 0.09% by weight of bis triethoxysilyl ethane (BTSE), an aqueous solution having a pH adjusted to 11.2 (the surface Treatment liquid) was applied by a dip or bar coater to form a surface treatment film, and aluminum alloy materials of the examples and comparative examples were produced. Ethanol and acetic acid were used for dissolution of BTSE and pH adjustment in the preparation process of the aqueous solution (surface treatment solution), but no fluorine-based drug was used. The amount of ethanol in the entire solution was about 2%. In addition, drying after application | coating of a surface treatment liquid was performed for 1 minute at 105 degreeC. The coating amount after drying was confirmed to be about 4 mg / m ^{2 by} measurement with before and after coating with fluorescent X-rays.

<Example 10>
To the oxide film on the surface of the aluminum alloy substrate on which the oxide film was formed, obtained in Example 1, 0.1% by mass of sodium metasilicate (a molar ratio of SiO ₂ and Na ₂ O of about 1), An aqueous solution (surface treatment solution) containing 0.09% by mass of bistriethoxysilylethane (BTSE) and having a pH adjusted to 11.2 was applied by a bar coater to form a surface treatment film. An aluminum alloy material was produced. Ethanol and acetic acid were used for dissolution of BTSE and pH adjustment in the preparation process of the aqueous solution (surface treatment solution), but no fluorine-based drug was used. The amount of ethanol in the entire solution was about 2%. In addition, drying after application | coating of a surface treatment liquid was performed for 1 minute at 105 degreeC. The coating amount after drying was confirmed to be 3.8 mg / m ² by measurement with before and after coating with fluorescent X-rays.

<Example 11>
0.1% by mass of water glass (SiO ₂ to Na ₂ O molar ratio of 3 to 3.4) was added to the oxide film on the surface of the aluminum alloy substrate on which the oxide film was formed, obtained in Example 1. And an aqueous solution (surface treatment liquid) containing 0.09% by mass of bistriethoxysilylethane (BTSE) and having a pH adjusted to 11.2 is applied by a bar coater to form a surface treatment film. 11 aluminum alloy materials were produced. Ethanol and acetic acid were used for dissolution of BTSE and pH adjustment in the preparation process of the aqueous solution (surface treatment solution), but no fluorine-based drug was used. The amount of ethanol in the entire solution was about 2%. In addition, drying after application | coating of a surface treatment liquid was performed for 1 minute at 105 degreeC. The coating amount after drying was confirmed to be 4.2 mg / m ² by fluorescence X-ray and measurement before and after coating.

<Comparative Example 3>
In the oxide film on the surface of the aluminum alloy substrate on which the oxide film was formed, obtained in Example 1, 0.55% by mass of crystalline layered sodium silicate (SiO _2: Na ₂ O molar ratio is about 2) (Pre-feed made by Tokuyama Siltec) and 0.05% by mass of bistriethoxysilylethane (BTSE), and an aqueous solution (surface treatment liquid) adjusted to pH 12.1 was applied by a bar coater. A treatment film was formed, and an aluminum alloy material of Comparative Example 3 was produced. Ethanol and acetic acid were used for dissolution of BTSE and pH adjustment in the preparation process of the aqueous solution (surface treatment solution), but no fluorine-based drug was used. The amount of ethanol in the entire solution was about 2%. In addition, drying after application | coating of a surface treatment liquid was performed for 1 minute at 105 degreeC. The coating amount after drying was confirmed to be 35 mg / m ² by fluorescence X-rays and measured before and after coating.

<Comparative Example 4>
0.061 mass% crystalline layered sodium silicate (Molar ratio of SiO ₂ to Na ₂ O is about 2) on the oxide film on the surface of the aluminum alloy substrate on which the oxide film was formed, obtained in Example 1 (Pre-feed made by Tokuyama Siltec) and 0.8% by mass of bistriethoxysilylethane (BTSE), and an aqueous solution (surface treatment solution) adjusted to pH 11.0 was applied with a bar coater. A treatment film was formed, and an aluminum alloy material of Comparative Example 4 was produced. Ethanol and acetic acid were used for dissolution of BTSE and pH adjustment in the preparation process of the aqueous solution (surface treatment solution), but no fluorine-based drug was used. The amount of ethanol in the entire solution was about 2%. In addition, drying after application | coating of a surface treatment liquid was performed for 1 minute at 105 degreeC. The coating amount after drying was confirmed to be 36 mg / m ² by fluorescence X-rays and measured before and after coating.

The press oil diluted with toluene was applied to the surface of the aluminum alloy material according to each of Examples and Comparative Examples produced in this way so that the coating amount after drying was 1 g / m ² .

<Measurement of oxide film components>
After forming the oxide film and before forming the surface treatment film, the oxide film of the aluminum alloy base material according to each of Examples and Comparative Examples was subjected to high-frequency glow discharge emission spectroscopy (GD-OES: model manufactured by Horiba Joban Yvon) JY-5000RF) while sputtering in the film thickness direction, metal elements such as aluminum (Al), magnesium (Mg), copper (Cu), iron (Fe), and titanium (Ti), and oxygen (O), The amount of each component was measured for elements such as nitrogen (N), carbon (C), silicon (Si) and sulfur (S). For magnesium (Mg), copper (Cu) and silicon (Si), the maximum concentration of magnesium (Mg), copper (Cu) and silicon (Si) in the oxide film was defined as the film concentration in the film. 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). Note that oxygen (O) is likely to be affected by contamination at the outermost surface and in the vicinity thereof, and it is difficult to measure the exact concentration. However, the oxide film of all samples contains oxygen (O). It was clear that

<Etching amount>
The etching amount (unit: g / cm ² ) is obtained by measuring the amount of decrease in the weight of the base material before and after the oxide film formation step (unit: g) and dividing this by the surface area of the base material (unit: m ² ). Calculated.

<Cohesive failure rate (adhesion durability)>
10A and 10B are diagrams schematically showing a method for measuring the cohesive failure rate, FIG. 10A is a side view, and FIG. 10B is a plan view. As shown in FIG. 10A and FIG. 10B, the end portions of two specimens 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%). In addition, a small amount of glass beads (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 held in a high temperature and humidity environment of 50 ° C. and a relative humidity of 95% for 30 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 adhesion 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 that the cohesive failure rate is less than 60% as bad (x), 60% or more and less than 70% is slightly good (Δ), 70% or more and less than 90% is good (◯), and 90% or more is particularly good. (◎) and 60% or more was accepted.

The above results are summarized in Table 1.

As shown in Table 1 above, the aluminum alloy material of Comparative Example 1 in which the concentration of Cu in the oxide film is out of the range specified in the present invention has a poor cohesive failure rate of less than 60%, and is in a high temperature humid environment. The adhesion durability was inferior.
Further, the aluminum alloy material of Comparative Example 2 manufactured without pickling or alkali cleaning has a Mg concentration in the oxide film that is out of the scope of the present invention, and the cohesive failure rate is less than 60%. It was inferior in adhesion durability in a high-temperature and humid environment.
Further, the aluminum alloy material of Comparative Example 3 in which the concentration of silicate in the surface treatment liquid is out of the range defined in the present invention has a poor cohesive failure rate of less than 60%, and the adhesion durability in a high-temperature and humid environment. It was inferior in nature.
In addition, the aluminum alloy material of Comparative Example 4 in which the concentration of the organosilane compound in the surface treatment liquid is out of the range defined in the present invention has a poor cohesive failure rate of less than 60%, and the adhesion durability in a high-temperature and humid environment. It was inferior in nature.

In contrast, all of the aluminum alloy materials of Examples 1 to 11 obtained by the production method of the present invention had a cohesive failure rate of 60% or more, and had good adhesion durability in a high-temperature and humid environment. .
In Examples 10, instead of the crystalline layered sodium silicate as used in Example 1 (molar ratio of SiO ₂ and Na ₂ O of about 2) (Tokuyama Siltech made pre feed), sodium metasilicate (SiO ₂ And the Na ₂ O molar ratio is about 1), and is an example produced under substantially the same conditions as in Example 1 except that the sodium silicate species was changed. In Example 10 the molar ratio of SiO ₂ and Na ₂ O was used sodium metasilicate less than 1.5 (about 1), although the cohesive failure rate was less than 90% to 70% pass level, SiO ₂ The cohesive failure rate was slightly inferior to Example 1 using crystalline layered sodium silicate in which the molar ratio of Na ₂ O was about 2.
Further, in Example 11, instead of the crystalline layered sodium silicate (a molar ratio of SiO ₂ and Na ₂ O of about 2) used in Example 1 (pre-feed made by Tokuyama Siltec), water glass (SiO ₂ and This is an example in which the molar ratio of Na ₂ O is 3 to 3.4), and is an example prepared under substantially the same conditions as in Example 1 except that the sodium silicate species is changed. In Example 11 using a water glass having a molar ratio of SiO ₂ to Na ₂ O of 1.5 or more (about 3 to 3.4), a crystalline layered structure having a molar ratio of SiO ₂ to Na ₂ O of about 2 A cohesive failure rate equivalent to that in Example 1 using sodium silicate was obtained.

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.
The present application includes a Japanese patent application filed on July 9, 2015 (Japanese Patent Application No. 2015-138049), a Japanese patent application filed on May 10, 2016 (Japanese Patent Application No. 2016-094922), Based on a Japanese patent application filed on June 7, 2016 (Japanese Patent Application No. 2016-113753), which is incorporated by reference in its entirety.

DESCRIPTION OF SYMBOLS 1 Oxide film 2 Surface treatment film 3 Base material 4 Adhesive resin layer 5, 35 Adhesive resin 6, 10 Aluminum alloy material 11 Aluminum alloy material with an adhesive resin layer 7 Resin molding 20, 21, 21a, 21b, 22, 23a, 23b Joined body 31a, 31b Specimen

Claims (8)

1. An oxide film forming step of forming an oxide film containing Mg in an amount of 0.1 atomic% or more and less than 30 atomic% and Cu regulated to less than 0.6 atomic% on at least a part of the surface of the aluminum alloy substrate;
   At least part of the oxide film contains 0.001% by mass or more and less than 0.5% by mass of silicate and 0.001% by mass or more and less than 0.5% by mass of an organosilane compound, and has a pH of 7 A method for producing an aluminum alloy material, comprising: a surface treatment film forming step including applying an aqueous solution of 14 or less.
2. The method for producing an aluminum alloy material according to claim 1, wherein the organosilane compound includes a silane compound having a plurality of hydrolyzable trialkoxysilyl groups in the molecule, a hydrolyzate thereof, or a polymer thereof.
3. The silicate is a silicate represented by mM ₂ O · nSiO ₂ , wherein M is a monovalent cation, and m is the number of moles of M ₂ O and the number of moles of SiO _2. The method for producing an aluminum alloy material according to claim 1, wherein a ratio n / m to n is 1.5 or more.
4. The method for producing an aluminum alloy material according to claim 3, wherein M is sodium ion.
5. The method for producing an aluminum alloy material according to claim 1, wherein the oxide film forming step includes an etching treatment step, and an etching amount in the etching treatment step is 1.9 g / m ² or less.
6. 2. The method for producing an aluminum alloy material according to claim 1, wherein the aluminum alloy substrate is made of an Al—Mg alloy, an Al—Cu—Mg alloy, an Al—Mg—Si alloy, or an Al—Zn—Mg alloy. .
7. An aluminum alloy material obtained by the method for producing an aluminum alloy material according to any one of claims 1 to 6.
8. A joined body obtained by joining the aluminum alloy material according to claim 7 and another member via an adhesive resin.

Images