JP5968956B2 - Aluminum alloy plate, joined body and automobile member using the same - Google Patents

Description

  The present invention relates to an aluminum alloy plate, and more particularly, to an aluminum alloy plate that can be suitably used for vehicles such as automobiles, ships, and aircraft, and particularly for automobile panels, and a joined body and an automobile member using the same.

Conventionally, various aluminum alloy plates have been widely used as members of transportation equipment such as automobiles, ships, and aircrafts according to the characteristics of each alloy. In particular, in consideration of recent global environmental problems such as CO ₂ emission, there is a demand for improvement in fuel consumption 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 plates is increasing.

  For example, examples of the aluminum alloy plate used as an automobile member include Mg-containing aluminum alloy plates such as a JIS 5000-based Al—Mg-based alloy plate and a JIS 6000-based Al—Mg—Si-based alloy plate. As a method for joining these aluminum alloy plates, welding, adhesion by an adhesive, or both are used in combination. While welding is joined at points and lines, bonding with adhesives joins the entire surface, so the bonding strength is higher and it is advantageous in terms of automobile crash safety, etc. Adhesion tends to increase.

  On the other hand, an aluminum alloy automobile member joined with an adhesive gradually enters an interface between moisture, oxygen, chloride ions, etc. during use, so that the interface between the adhesive layer and the aluminum alloy plate gradually increases. There was a problem that it deteriorated, interfacial peeling occurred, and the adhesive strength decreased.

  As a method of improving the adhesion durability of aluminum alloy automotive parts having an adhesive layer, a mechanically weak oxide film that exists near the surface of the aluminum alloy plate and causes interface peeling is applied with an adhesive. A method of removing in advance by pickling before performing (for example, refer to Patent Document 1), a method of anodizing the vicinity of the surface of an aluminum alloy plate, and providing a surface form that provides an anchor effect to the oxide film, an aluminum alloy A method of adjusting the Mg amount and OH amount of an oxide film by treating the surface of the plate with warm water (see, for example, Patent Documents 2 and 3) is generally known among those skilled in the art.

JP-A-6-256881 JP 2006-200007 A JP 2007-217750 A

  In the method of pickling described in Patent Document 1, since a mechanically weak oxide film containing a large amount of Mg as an alloy component is removed, initial interface peeling is prevented and the adhesive strength is improved. However, when exposed to a high-temperature and humid environment (deterioration environment) where moisture, oxygen, chloride ions, etc. penetrate, Cu, which is an alloy component, concentrates on the oxide film removal surface, and the Cu deteriorates the adhesive layer. A phenomenon called accelerated copper damage occurs. As a result, moisture or the like may permeate into the base (substrate) of the aluminum alloy plate, and there is a problem that the interface is deteriorated, causing the interface to peel and the adhesive strength is lowered.

  In addition, in the method of anodizing, in order to prevent the deterioration and peeling of the interface, it is necessary to form a thick oxide film to which a surface form for sufficiently improving the adhesion durability is formed. However, it takes a long time, and there is a problem that production efficiency deteriorates.

  In addition, in the method of performing the warm water treatment described in Patent Documents 2 and 3, the initial adhesive strength and the secondary adhesion after wetting are improved, but the interface hydration and the base material are exposed when exposed to a high temperature humid environment. As a result of the dissolution, the interface deteriorates, the interface peels off, and the adhesive strength decreases.

  The present invention is for solving the above-mentioned problems, and even when exposed to a high-temperature and humid environment, interface peeling at the bonding interface of the adhesive is unlikely to occur, and therefore, the adhesive strength is unlikely to decrease and the adhesion durability is improved. It is an object of the present invention to provide an excellent aluminum alloy plate, a joined body using the same, and an automobile member.

In order to solve the above problems, an aluminum alloy plate according to the present invention includes an aluminum alloy substrate containing magnesium and a surface oxide film formed on the surface of the aluminum alloy substrate, and the surface oxide film has an amount of zirconium. Is 0.01 to 10 atomic%, the amount of magnesium is 0.1 atomic% or more and less than 10 atomic%, and the amount of nitrogen is 6.9 atomic% or more and less than 17 atomic%.

  According to such a configuration, since the surface oxide film containing a predetermined amount of zirconium and magnesium is provided, even when the aluminum alloy plate is joined with the adhesive member, the adhesive member and the surface oxide film are exposed even when exposed to a high-temperature wet environment. Hydration at the interface with the aluminum alloy can be suppressed, and elution of the aluminum alloy substrate can be suppressed. As a result, interfacial peeling can be suppressed and a decrease in adhesive strength can be suppressed. In addition, since the content of both zirconium and magnesium is controlled, it is not affected by the type of adhesive that constitutes the adhesive member, and interfacial debonding has been applied to all adhesives conventionally used when joining aluminum alloy plates. Can be suppressed, and a decrease in adhesive strength can be suppressed. In addition, since the amount of nitrogen in the surface oxide film is within a predetermined range, the reaction between nitrogen in the surface oxide film and components contained in the adhesive is suppressed, and when the aluminum alloy plate is joined, the adhesive strength is further reduced. Can be suppressed.

The aluminum alloy plate according to the present invention preferably further includes an adhesive layer made of an adhesive on the surface of the surface oxide film.
According to such a configuration, since the aluminum alloy plate is provided with the adhesive layer in advance, when forming a joined body or an automobile member using the aluminum alloy plate, the operation of forming the adhesive member on the surface of the aluminum alloy plate is performed. Can be omitted.

  In the aluminum alloy plate according to the present invention, the ratio (Zr amount / Mg amount) of the zirconium amount (Zr amount) and the magnesium amount (Mg amount) of the surface oxide film is preferably 0.0025 to 80.

  According to such a configuration, since the ratio of the amount of zirconium and the amount of magnesium in the surface oxide film is within a predetermined range, hydration at the interface between the adhesive member (adhesive layer) and the surface oxide film can be further suppressed, The elution of the aluminum alloy substrate can be further suppressed. As a result, interfacial peeling can be further suppressed, and a decrease in adhesive strength can be further suppressed.

  In the aluminum alloy plate according to the present invention, the aluminum alloy substrate is preferably made of an Al—Mg alloy, an Al—Cu—Mg alloy, an Al—Mg—Si alloy, or an Al—Zn—Mg alloy.

  According to such a configuration, when the aluminum alloy substrate is composed of an alloy type having a relatively high magnesium content, magnesium is concentrated on the substrate surface, and a weak boundary layer is likely to be generated at the adhesion interface. Since the magnesium content of the surface oxide film formed on the surface is controlled within a predetermined range, specifically, the concentrated magnesium is removed and controlled within the predetermined range, the substrate is made of an alloy species having a relatively high magnesium content. However, interfacial peeling can be suppressed, and a decrease in adhesive strength can be suppressed.

  The joined body according to the present invention is a joined body in which the aluminum alloys not provided with an adhesive layer are joined to each other via an adhesive member made of an adhesive, and the adhesive member includes the two aluminum alloys. Bonded to the surface oxide film side of the plate, each of the surface oxide films of the two aluminum alloy plates is arranged to face each other with the adhesive member interposed therebetween.

  In the joined body according to the present invention, the second aluminum alloy plate made of an aluminum alloy is connected to the first aluminum alloy plate made of the aluminum alloy plate not provided with an adhesive layer via an adhesive member made of an adhesive. It is a joined body, wherein the adhesive member is joined to the surface oxide film side of the first aluminum alloy plate.

  Moreover, the joined body according to the present invention is a joined body in which the aluminum alloy plate not provided with the adhesive layer is joined to the adhesive layer side of the aluminum alloy plate provided with the adhesive layer. Each of the surface oxide films of the aluminum alloy plate is disposed so as to face each other with the adhesive layer interposed therebetween.

  Furthermore, the joined body according to the present invention is a joined body in which a second aluminum alloy plate made of an aluminum alloy is joined to a first aluminum alloy plate made of the aluminum alloy plate provided with an adhesive layer, The 2 aluminum alloy plate is bonded to the adhesive layer side of the first aluminum alloy plate.

  According to such a structure, it is comprised with the aluminum alloy plate provided with the surface oxide film containing predetermined amounts of zirconium and magnesium, and the adhesive member or the aluminum oxide plate (first aluminum alloy plate) on the surface oxide film side Since the adhesive layer is bonded, hydration at the interface between the adhesive member or the adhesive layer and the surface oxide film can be suppressed even when the bonded body is used in an automobile member, even if it is exposed to a high-temperature wet environment. At the same time, elution of the aluminum alloy substrate can be suppressed. As a result, interfacial peeling can be suppressed and a decrease in adhesive strength can be suppressed. In addition, since the contents of both the zirconium content and the magnesium content are controlled, it is not affected by the type of adhesive constituting the adhesive member or the adhesive layer, and has been conventionally used for joining aluminum alloy plates. In general agents, interfacial peeling can be suppressed, and a decrease in adhesive strength can be suppressed.

The automotive member according to the present invention is manufactured from the joined body.
According to such a configuration, since it is manufactured from the above-described joined body, even if the automotive member is exposed to a high-temperature and humid environment, in the joined body constituting the automotive member, the adhesive member or the adhesive layer Further, hydration at the interface with the surface oxide film can be suppressed, and elution of the aluminum alloy substrate can be suppressed. As a result, interfacial peeling can be suppressed and a decrease in adhesive strength can be suppressed.

  According to the present invention, even when exposed to a high-temperature and humid environment, it is difficult for interface peeling at the bonding interface of the adhesive to occur, and therefore, the adhesive strength is unlikely to decrease, the adhesion durability is excellent, and the adhesion durability. However, it is possible to provide an aluminum alloy plate that is not affected by the type of adhesive, and a joined body using the same. Moreover, the member for motor vehicles excellent in adhesion durability can be provided.

(A), (b) is sectional drawing which shows typically the structure of the aluminum alloy plate which concerns on this invention. It is a process flow which shows the manufacturing method of the aluminum alloy plate of Fig.1 (a), (b). (A)-(d) is sectional drawing which shows typically the structure of the conjugate | zygote based on this invention. The shape of the adhesion test body produced in the Example is shown, (a) is a side view, and (b) is a plan view.

≪Aluminum alloy plate≫
Hereinafter, the aluminum alloy plate according to the present invention will be specifically described with reference to FIG. As shown in FIG. 1A, an aluminum alloy plate 10 includes an aluminum alloy substrate 1 (hereinafter referred to as a substrate) and a surface oxide film 2 formed on the surface of the substrate 1. As will be described later, in the manufacturing method, the surface oxide film 2 first forms an oxide film, and then the surface of the formed oxide film is treated with a zirconium salt aqueous solution so that zirconium dioxide adheres to the oxide film. Alternatively, it is formed as a film that enters and the magnesium content of the oxide film is controlled.
Here, the surface of the substrate 1 means at least one surface of the surface of the substrate 1 and includes so-called one side and both sides.
Hereinafter, each structure of the aluminum alloy plate 10 will be described.

<Board>
The substrate 1 is made of an aluminum alloy, and is appropriately selected from various non-heat-treatable aluminum alloys or heat-treatable aluminum alloys specified by JIS or similar to JIS, depending on the use of the aluminum alloy plate 10. Non-heat treatment type aluminum alloys are pure aluminum (1000 series), Al-Mn series alloys (3000 series), Al-Si series alloys (4000 series) and Al-Mg series alloys (5000 series). Aluminum alloys are an Al-Cu-Mg alloy (2000 series), an Al-Mg-Si alloy (6000 series), and an Al-Zn-Mg alloy (7000 series).

  As a specific example, when the aluminum alloy plate 10 is used for an automobile, it is preferably a high-strength substrate having a 0.2% proof stress of 100 MPa or more. As an aluminum alloy that constitutes a substrate satisfying such characteristics, it contains a relatively large amount of magnesium of 2000 series, 5000 series, 6000 series, 7000 series, etc., which is generally used for this type of structural member application, A general-purpose alloy having a relatively high yield strength, and an aluminum alloy that is tempered as necessary is preferably used. It is preferable to use a 6000 series aluminum alloy in terms of excellent age-hardening ability and a relatively small amount of alloying elements and excellent scrap recyclability and formability.

<Surface oxide film>
The surface oxide film 2 is formed as a film containing a predetermined amount of zirconium, magnesium and nitrogen on the surface of the substrate 1 in order to improve the adhesion durability even when exposed to a high temperature and humidity environment. . Here, the surface oxide film 2 is formed by forming a surface of the oxide film on the surface of the substrate 1 by heat treatment in a surface oxide film forming step S2 (see FIG. 2) described later, and then converting the surface of the oxide film to a zirconium salt. The surface oxide film 2 is formed of the entire oxide film that has been surface-treated with an aqueous solution.

(Zirconium content)
The surface oxide film 2 has a zirconium content in the range of 0.01 to 10 atomic%. By including zirconium so that the amount of zirconium in the surface oxide film 2 is 0.01 to 10 atomic%, the stability of the surface oxide film 2 against deterioration factors such as water, oxygen, and chloride ions is increased, and an adhesive is provided. Hydration at the interface between the surface oxide film 2 and the surface oxide film 2 is suppressed, and elution of the substrate 1 is suppressed. As a result, the adhesion durability of the aluminum alloy plate 10 is improved. When the amount of zirconium in the surface oxide film 2 is less than 0.01 atomic%, there is no effect, and when it exceeds 10 atomic%, the effect is saturated. The amount of zirconium is preferably 0.02 to 8 atomic%, and more preferably 0.04 to 6 atomic%. Examples of the method of incorporating zirconium into the surface oxide film 2 include surface treatment of the surface oxide film 2 with an aqueous solution of a zirconium salt such as zirconium nitrate, zirconium sulfate, or zirconium acetate. Further, in order to adjust the zirconium amount of the surface oxide film 2, the desired zirconium amount can be obtained by adjusting the surface treatment time, temperature, concentration of the surface treatment liquid, and pH.

(Magnesium content)
The surface oxide film 2 has a magnesium amount in the range of 0.1 atomic% or more and less than 10 atomic%.
The aluminum alloy constituting the substrate 1 usually contains magnesium as an alloy component. And in the surface oxide film 2 formed on the surface of the substrate 1, magnesium is present on the surface in a concentrated state, and the magnesium becomes a weak boundary layer of the adhesion interface, and the initial adhesion durability is lowered. Further, in a high temperature and humid environment in which moisture, oxygen, chloride ions, etc. penetrate, it causes hydration of the interface with the adhesive and dissolution of the substrate 1, thereby reducing the adhesion durability of the aluminum alloy plate 10. Therefore, the surface treatment of the surface oxide film 2 adjusts the magnesium content to less than 10 atomic% to improve the adhesion durability. The amount of magnesium is preferably less than 8 atomic%, and more preferably less than 6 atomic%. The lower limit of the amount of magnesium is 0.1 atomic% or more from the viewpoint of economy. As an adjustment method for adjusting the magnesium amount of the surface oxide film 2, for example, the surface oxide film 2 is surface-treated with an acid such as nitric acid or sulfuric acid, or an aqueous solution such as a zirconium salt, and the treatment time, temperature, and surface treatment solution of the surface treatment. By adjusting the concentration and pH, the desired amount of magnesium can be obtained. That is, the magnesium amount of the surface oxide film 2 is adjusted by dissolving the magnesium of the surface oxide film 2 in the acid or zirconium salt aqueous solution.

  Further, even if the zirconium amount and the magnesium amount of the surface oxide film 2 are individually controlled, the effect of improving the adhesion durability is seen as compared with the case where it is not controlled. However, if either the amount of zirconium or the amount of magnesium in the surface oxide film 2 is controlled, the improvement effect may not be observed depending on the type of adhesive, and stable adhesion durability is not exhibited. Depending on the type of adhesive, some adhesives have a sensitive effect on the amount of magnesium, and some adhesives have a sensitive effect on the amount of zirconium. In order to improve the properties, it is important to control both the zirconium content and the magnesium content.

  Further, the surface oxide film 2 preferably has a ratio (Zr amount / Mg amount) of zirconium amount (Zr amount) to magnesium amount (Mg amount) of 0.0025 to 80. When the ratio (Zr amount / Mg amount) is within a predetermined range, hydration at the interface between the adhesive and the surface oxide film 2 can be further suppressed, and elution of the substrate 1 can be further suppressed. As a result, the interfacial peeling can be further suppressed, the decrease in the adhesive strength of the aluminum alloy plate 10 can be further suppressed, and the adhesion durability is further improved.

(Nitrogen content)
The surface oxide film 2 has a nitrogen content in the range of less than 17 atomic% together with the zirconium content and the magnesium content. When the amount of nitrogen in the surface oxide film 2 is less than 17 atomic%, the adhesion durability of the aluminum alloy plate 10 is further stably improved. Even if the nitrogen amount of the surface oxide film 2 is 17 atomic% or more, a certain degree of adhesion durability can be obtained, but stable adhesion durability cannot be obtained as compared with those having a nitrogen content of less than 17 atomic%. Nitrogen in the surface oxide film 2 is a contamination component (for example, nitrogen-containing compounds such as amino acids or ammonium salts) in the surface treatment liquid, zirconium nitrate as the surface treatment liquid, and nitric acid added to adjust the pH of the surface treatment liquid. It is a component derived from. When the amount of nitrogen in the surface oxide film 2 is 17 atomic% or more, specifically, when there are many contaminant components and nitrate ions in the surface treatment liquid, they are contained in the nitrogen and adhesive in the surface oxide film 2. The component which reacts reacts, an adhesive agent changes in quality at the time of hardening, and the adhesive durability of the aluminum alloy plate 10 becomes easy to fall. The amount of nitrogen in the surface oxide film 2 is preferably less than 16 atomic%, and more preferably less than 15 atomic%.

  Further, the surface oxide film 2 contains the above-mentioned predetermined amount of zirconium, the above-mentioned predetermined amount of magnesium, and the above-mentioned predetermined amount of nitrogen, and is substantially free of halogen and phosphorus. It is preferable. “Substantially free of halogen and phosphorus” means, for example, when halogen and phosphorus are measured, fluorine: less than 0.1 atomic%, chlorine: less than 0.1 atomic%, bromine: less than 0.1 atomic%, iodine : Less than 0.1 atomic%, astatine: less than 0.1 atomic%, phosphorus: less than 0.1 atomic%. And when the surface oxide film 2 contains a halogen, a load is applied to the production equipment corresponding to the halogen. Further, when the surface oxide film 2 contains phosphorus, precipitation is likely to occur when the surface treatment liquid is drained, and the environment is likely to be contaminated.

  In addition to the above elements (zirconium, magnesium, nitrogen, halogen, and phosphorus), the balance of the surface oxide film 2 is composed of oxygen, aluminum, and impurities. Preferable contents of oxygen and aluminum are 15 to 80 atomic%, respectively. Impurities include C, Si, Ca, Fe, Cu, Mn, Ti, Zn, Ni, etc. Content of less than 10 atomic percent is acceptable for C, and content of less than 7 atomic percent is acceptable for other impurities. The

(Film thickness)
The surface oxide film 2 preferably has a thickness of 1 to 30 nm. When the film thickness is less than 1 nm, the rust preventive oil used when the substrate 1 is manufactured, and the joined body (see FIGS. 3A to 3D) and the automotive member (not shown) from the aluminum alloy plate 10 are not shown. ) Is suppressed from adsorbing the ester component in the press oil used. Therefore, even if the surface oxide film 2 is not present, the degreasing property, chemical conversion property, and adhesion durability of the aluminum alloy plate 10 are ensured, but an excessive amount of acid is required to control the film thickness of the surface oxide film 2 to less than 1 nm. Cleaning is required, resulting in poor productivity and low practicality. On the other hand, when the film thickness of the surface oxide film 2 exceeds 30 nm, the film amount is excessive, so that the surface is likely to be uneven, and as a result, chemical unevenness is likely to occur, and the chemical conversion property tends to be lowered. In addition, the more preferable range of a film thickness is 10-20 nm.

  The film thickness of the surface oxide film 2 is largely determined by the oxide film formed by the heat treatment in the surface oxide film formation step S2 (see FIG. 2) described later. In the surface treatment with an aqueous solution of zirconium salt described later, zirconium dioxide adheres to or enters the oxide film, and the amount of magnesium contained in the oxide film is controlled. Therefore, most of the oxide film formed by the heat treatment is used. It is determined by the film thickness. The film thickness of the oxide film is controlled by the heating temperature. The oxide film formed by the heat treatment is an uneven porous film formed on the surface of the substrate 1 and is a film mainly composed of magnesium oxide.

(Element amount and thickness measurement method in surface oxide film)
The amount of elements (zirconium amount, magnesium amount, nitrogen amount, halogen amount, phosphorus amount, etc.) in the surface oxide film 2 formed on the surface of the substrate 1 is GD-OES (Glow Discharge Optical Emission Spectroscopy). )), And the measured maximum value of the predetermined element when the measured value of the oxygen amount in the depth profile of the surface oxide film 2 is 15 atomic% or less was taken as the element amount. GD-OES can also measure the film thickness of the surface oxide film 2. That is, the depth at which the measured value of the oxygen amount is 15 atomic% or less in the depth profile measured by GD-OES can be used as the film thickness of the surface oxide film 2. Needless to say, the element amount and the film thickness can be average values of several measurement results on the surface of the surface oxide film 2. The amount of zirconium can also be determined from the amount of zirconium dioxide in the surface oxide film 2. That is, the amount of zirconium dioxide is obtained, and the amount of zirconium is calculated from the obtained amount of zirconium dioxide by a predetermined calculation.

  In addition, the element amount and film thickness measurement methods are not particularly limited to GD-OES as long as they have the same accuracy as GD-OES, and are not limited to GD-OES. AES (Auger electron spectroscopy), XPS (X-ray photoelectron spectroscopy) ) Etc.

As shown in FIG. 1B, the aluminum alloy plate 10A according to the present invention preferably further includes an adhesive layer 3 made of an adhesive on the surface of the surface oxide film 2.
<Adhesive layer>
The adhesive constituting the adhesive layer 3 is not particularly limited, and an adhesive that has been conventionally used when joining aluminum alloy plates can be used. For example, a thermosetting epoxy resin, an acrylic resin, a urethane resin, etc. are mentioned. Although the thickness of the adhesive bond layer 3 is not specifically limited, 10-500 micrometers is preferable and 50-200 micrometers is more preferable. When the thickness of the adhesive layer 3 is less than 10 μm, the aluminum alloy plate 10A and the aluminum alloy plate 10 (see FIG. 1A) not provided with another adhesive layer are interposed via the adhesive layer 3. In some cases, it cannot be joined with high adhesion durability. That is, the adhesion durability of the joined body 20B in FIG. When the thickness of the adhesive layer 3 exceeds 500 μm, the cohesive failure strength may be reduced.

≪Aluminum alloy sheet manufacturing method≫
Next, a method for manufacturing the aluminum alloy plate will be described with reference to FIG. For the configuration of the aluminum alloy plate, refer to FIGS. 1 (a) and 1 (b).

  The manufacturing method of the aluminum alloy plate 10 includes a substrate manufacturing step S1 and a surface oxide film forming step S2. Hereinafter, each step will be described.

<Substrate manufacturing process>
The substrate manufacturing step S1 is a step of manufacturing the substrate 1 by rolling. Specifically, it is preferable to produce the substrate 1 by the following procedure.

  An aluminum alloy having a predetermined composition is melted and cast by continuous casting to produce an ingot (melting casting step), and the produced ingot is subjected to homogenization heat treatment (homogenization heat treatment step). Next, the ingot subjected to the homogenization heat treatment is hot-rolled to produce a hot-rolled sheet (hot-rolling step). Next, the hot-rolled sheet is subjected to rough annealing or intermediate annealing at 300 to 580 ° C., and cold-rolling at a final cold rolling rate of 5% or more is performed at least once to obtain a cold-rolled sheet having a predetermined thickness (substrate 1). Is manufactured (cold rolling process). By setting the temperature of rough annealing or intermediate annealing to 300 ° C. or higher, the effect of improving the moldability is more exhibited, and by setting it to 580 ° C. or lower, it becomes easy to suppress a decrease in moldability due to the occurrence of burning. By making the final cold rolling rate 5% or more, the effect of improving the formability is more exhibited. In addition, the conditions of homogenization heat processing and hot rolling are not specifically limited, The conditions in the case of obtaining a hot rolled sheet normally may be sufficient. Further, intermediate annealing may not be performed.

<Surface oxide film formation process>
The surface oxide film forming step S2 is a step of forming the surface oxide film 2 on the surface of the substrate 1 produced in the previous step S1. Then, for example, the substrate 1 is subjected to a heat treatment, followed by a surface treatment, thereby adjusting the zirconium amount, the magnesium amount, and the nitrogen amount of the surface oxide film 2 within a predetermined range.

(Heat treatment)
In the heat treatment, the substrate 1 is heated to 400 to 580 ° C. to form an oxide film constituting the surface oxide film 2 on the surface of the substrate 1. The heat treatment also adjusts the strength of the aluminum alloy plate 10. Note that the heat treatment is preferably rapid heating at a heating rate of 100 ° C./min or more.

  The heat treatment is a solution treatment when the substrate 1 is made of a heat-treatable aluminum alloy, and is a heat treatment in annealing (final annealing) when the substrate 1 is made of a non-heat-treatable aluminum alloy.

  By rapidly heating to a heating temperature of 400 ° C. or higher, the strength of the aluminum alloy plate 10 and the strength after heating (baking) of the aluminum alloy plate 10 are further increased. By rapidly heating to a heating temperature of 580 ° C. or less, a decrease in moldability due to the occurrence of burning is suppressed. Further, by heating at a heating temperature of 400 to 580 ° C., an oxide film having a thickness of 1 to 30 nm constituting the surface oxide film 2 is formed on the surface of the substrate 1. In addition, from the viewpoint of improving the strength, the holding time is preferably 3 to 30 seconds.

(surface treatment)
In the surface treatment, the surface of the substrate 1 on which the oxide film is formed is subjected to a surface treatment. By this surface treatment, the oxide film formed by the heat treatment, that is, the surface oxide film 2 in which the oxide film is surface-treated. The amount of zirconium, the amount of magnesium and the amount of nitrogen are adjusted to a predetermined range.

  In the surface treatment, a zirconium salt aqueous solution having a concentration of 0.01 to 15% by mass and a pH of less than 5 is used as the surface treatment liquid. In the surface treatment, an acid such as nitric acid or sulfuric acid may be added to adjust the pH. Furthermore, in the surface treatment, the treatment temperature is 10 to 90 ° C., and the treatment time is 1 to 200 seconds. In this surface treatment, for example, the substrate 1 on which the oxide film is formed is sprayed with a zirconium salt aqueous solution by showering or spraying, passed through the zirconium salt aqueous solution, or immersed in the zirconium salt aqueous solution. Thus, the surface treatment of the substrate 1 is performed. Moreover, as a surface treatment liquid, the amount of nitrogen to contain is less than 17 atomic%. Alternatively, it is preferable to use a material that does not contain halogen and phosphorus.

  By using a 0.01-15 mass% zirconium salt aqueous solution as the surface treatment liquid, the surface oxide film 2 has a zirconium content of 0.01-10 atomic% and a magnesium content of 0.1 atomic% or more and 10 atoms. %. When the concentration of the zirconium salt aqueous solution is less than 0.01% by mass, the amount of zirconium in the surface oxide film 2 is small (less than 0.01 atomic%) and the amount of magnesium is large (10 atomic% or more). The durability of adhesion cannot be ensured. On the other hand, when the concentration of the zirconium salt aqueous solution exceeds 15% by mass, the surface oxide film 2 has a large amount of zirconium (exceeding 10 atomic%) or a small amount of magnesium (less than 0.1 atomic%), resulting in adhesion durability. The effect of improving the property is saturated. The concentration of the zirconium salt aqueous solution is preferably 0.01 to 15% by mass.

  When the pH of the zirconium salt aqueous solution as the surface treatment liquid exceeds 5, the stability of the surface treatment liquid is lowered, and precipitation is likely to occur in the surface treatment liquid. If precipitation occurs in the surface treatment liquid, the precipitate is pushed into the plate surface of the aluminum alloy plate 10 as a foreign substance, resulting in poor appearance, which is not preferable. The pH of the zirconium salt aqueous solution as the surface treatment liquid is preferably less than 5.

  When the treatment temperature of the zirconium salt aqueous solution as the surface treatment liquid is less than 10 ° C. or the treatment time is less than 1 second, the zirconium content of the surface oxide film 2 is less than 0.01 atomic% and the magnesium content is 10 atomic% or more. The adhesion durability of the aluminum alloy plate 10 cannot be ensured. On the other hand, when the treatment temperature of the zirconium salt aqueous solution exceeds 90 ° C. or the treatment time exceeds 200 seconds, the zirconium content of the surface oxide film 2 exceeds 10 atomic% or the magnesium content is 0.1 atomic%. The adhesion durability improving effect is saturated. The treatment temperature of the aqueous zirconium salt solution is preferably 10 to 90 ° C., and the treatment time is preferably 1 to 200 seconds.

  Even if the amount of nitrogen in the zirconium salt aqueous solution as the surface treatment liquid is 17 atomic% or more, the adhesion durability of the aluminum alloy plate 10 of the present invention can be achieved, but compared with the case where the amount of nitrogen is less than 17 atomic%, Stable adhesion durability cannot be improved. Further, the zirconium salt aqueous solution as the surface treatment liquid does not contain halogen and phosphorus, as described above, when halogen and phosphorus are measured by GD-OES or the like, it cannot be measured, that is, less than the measurement limit. Means. And when a surface treatment liquid contains a halogen, a load is applied to manufacturing equipment. Further, when the surface treatment liquid contains phosphorus, precipitation tends to occur when the surface treatment liquid is drained, and the environment is likely to be contaminated. The nitrogen amount, halogen amount, and phosphorus amount in the surface treatment liquid are controlled simultaneously when the zirconium amount and magnesium amount in the surface treatment liquid are controlled by the concentration and treatment conditions.

  Further, prior to the surface treatment with the above-described zirconium salt aqueous solution, for the purpose of removing magnesium from the surface oxide film 2, that is, to make the magnesium amount of the surface oxide film 2 0.1 atomic% or more and less than 10 atomic%. In addition, surface treatment using acid such as nitric acid or sulfuric acid as the surface treatment liquid, so-called acid cleaning may be performed. The acid cleaning conditions are preferably an acid concentration of 0.5 to 6 N, a pH of less than 1, a cleaning temperature of 20 to 80 ° C., and a cleaning time of 1 to 100 seconds.

  Next, a manufacturing method of the aluminum alloy plate 10A provided with the adhesive layer 3 will be described. The manufacturing method of the aluminum alloy plate 10A includes a substrate manufacturing step S1, a surface oxide film forming step S2, and an adhesive layer forming step S3. Since the substrate manufacturing step S1 and the surface oxide film forming step S2 are as described above, description thereof is omitted.

<Adhesive layer forming step>
The adhesive layer forming step S3 is a step of forming the adhesive layer 3 made of an adhesive on the surface of the surface oxide film 2 formed in the step S2. The method for forming the adhesive layer 3 is not particularly limited. For example, when the adhesive is solid, the adhesive is in a liquid state after being dissolved in a solvent to form a solution. In some cases, there may be mentioned a method of spraying or coating the surface of the surface oxide film 2 as it is.

The manufacturing method of the aluminum alloy plates 10 and 10A is as described above. However, when the aluminum alloy plates 10 and 10A are manufactured, the manufacturing method of the aluminum alloy plates 10 and 10A is performed between or before and after each step within a range that does not adversely affect the respective steps. Other steps may be included. For example, a preliminary aging treatment step of performing a preliminary aging treatment after the surface oxide film formation step S2 or the adhesive layer formation step S3 may be provided. The preliminary aging treatment is preferably performed by heating at 40 to 120 ° C. for 8 to 36 hours at a low temperature within 72 hours. By performing the 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 plates 10 and 10A, a defective product removing step for removing defective products generated in each step, and the like may be included.

The manufactured aluminum alloy plates 10 and 10A are coated with press oil on the surface thereof before the bonded body is manufactured or before it is formed into an automobile member. As the press oil, one containing an ester component is mainly used.
Next, a method for applying press oil to the aluminum alloy plates 10 and 10A according to the present invention will be described.
As a method of applying the press oil, for example, the aluminum alloy plates 10 and 10A may be simply immersed in press oil containing ethyl oleate as an ester component. The method and conditions for applying the press oil containing the ester component are not particularly limited, and general methods and conditions for applying the press oil can be widely applied. Further, the ester component is not limited to ethyl oleate, and various materials such as butyl stearate and sorbitan monostearate can be used.

≪Joint body≫
Next, the joined body according to the present invention will be described. In the following description, the aluminum alloy plates 10 and 10A will be described as having the surface oxide film 2 on one side (see FIGS. 1A and 1B).
As shown in FIG. 3A, the joined body 20 includes two aluminum alloy plates 10 and 10 and an adhesive member 11. Specifically, in the joined body 20, the aluminum alloy plates 10 and 10 are joined via the adhesive member 11. The adhesive member 11 has one surface bonded to the surface oxide film 2 side of one aluminum alloy plate 10 and the other surface bonded to the surface oxide film 2 side of the other aluminum alloy plate 10. As a result, the surface oxide films 2 and 2 of the two aluminum alloy plates 10 and 10 are arranged so as to face each other with the adhesive member 11 interposed therebetween.

<Aluminum alloy plate>
Since the aluminum alloy plate 10 is as described above, the description thereof is omitted.
<Adhesive member>
The adhesive member 11 is made of an adhesive and is the same as the adhesive layer 3 described above. Specifically, the adhesive member 11 is made of an adhesive such as a thermosetting epoxy resin, an acrylic resin, or a urethane resin. The thickness of the adhesive member 11 is not particularly limited, but is preferably 10 to 500 μm, more preferably 50 to 200 μm.

  In the joined body 20, as described above, both surfaces of the adhesive member 11 are joined to the surface oxide film 2 containing a predetermined amount of zirconium and magnesium. Therefore, when the joined body 20 is used as an automobile member, the temperature is high. Even when exposed to a moist environment, a decrease in the adhesive strength at the interface between the adhesive member 11 and the surface oxide film 2 is suppressed, and the adhesion durability is improved. In addition, the adhesive durability at the interface is improved in all adhesives conventionally used for joining aluminum alloy plates without being affected by the type of adhesive constituting the adhesive member 11.

  As shown in FIG. 3 (b), the joined body 20A uses the second aluminum alloy plate 12 for one of the two aluminum alloy plates 10 and 10 (see FIG. 3 (a)) of the joined body 20 described above. It is. Specifically, a second aluminum alloy plate 12 made of an aluminum alloy is joined to a first aluminum alloy plate 10a made of an aluminum alloy plate 10 via an adhesive member 11, and the adhesive member 11 is made of a first aluminum alloy plate. It is joined to the surface oxide film 2 side of 10a. The first aluminum alloy plate 10a is made of the aluminum alloy plate 10, and the aluminum alloy plate 10 is as described above, and thus the description thereof is omitted.

<Second aluminum alloy plate>
The second aluminum alloy plate 12 is the same as the substrate 1 described above, and is specifically made of various non-heat-treatable aluminum alloys or heat-treatable aluminum alloys that are defined in JIS or approximate to JIS.

  In the joined body 20A, since one surface of the adhesive member 11 is joined to the surface oxide film 2 side, like the above-described joined body 20, when the joined body 20A is used as a member for an automobile, it is exposed to a high-temperature and humid environment. However, the adhesion durability at the interface is improved, and in addition, the adhesion durability is not affected by the type of the adhesive.

  As shown in FIG. 3C, the joined body 20 </ b> B includes an aluminum alloy plate 10 </ b> A (see FIG. 1B) that includes the adhesive layer 3 and an aluminum alloy plate 10 that does not include the adhesive layer 3. Prepare. Specifically, the surface oxide film 2 of the aluminum alloy plate 10 is bonded to the adhesive layer 3 side of the aluminum alloy plate 10A. As a result, each of the surface oxide films 2 and 2 of the two aluminum alloy plates 10A and 10 is disposed so as to face each other through the adhesive layer 3 of the aluminum alloy plate 10A. Since the two aluminum alloy plates 10A and 10 are as described above, description thereof is omitted.

  In the joined body 20B, since both surfaces of the adhesive layer 3 are joined to the surface oxide film 2 side, like the above-described joined body 20, when the joined body 20B is used as a member for an automobile, it is exposed to a high temperature and humid environment. However, the adhesion durability at the interface is improved, and in addition, the adhesion durability is not affected by the type of the adhesive.

  As shown in FIG. 3D, the joined body 20C includes a second aluminum alloy plate 12 instead of the aluminum alloy plate 10 (see FIG. 3C) that does not include the adhesive layer 3 of the joined body 20B. Is used. Specifically, a second aluminum alloy plate 12 made of an aluminum alloy is joined to a first aluminum alloy plate 10Aa made of an aluminum alloy plate 10A provided with an adhesive layer 3, and the second aluminum alloy plate 12 is joined to the adhesive layer 3 side of the first aluminum alloy plate 10Aa. The first aluminum alloy plate 10Aa is composed of the aluminum alloy plate 10A, and the aluminum alloy plate 10A is as described above, and thus the description thereof is omitted. Moreover, since the 2nd aluminum alloy plate 12 is as above-mentioned, description is abbreviate | omitted.

  In the joined body 20C, since one surface of the adhesive layer 3 is joined to the surface oxide film 2 side, similarly to the above-described joined body 20, when the joined body 20C is used for an automobile member, it is exposed to a high temperature and humid environment. However, the adhesion durability at the interface is improved, and in addition, the adhesion durability is not affected by the type of the adhesive.

  As a manufacturing method of the joined body 20, 20A to 20C, specifically, a joining method, a conventionally known joining method is used. The method for forming the adhesive member 11 is not particularly limited. For example, the adhesive member 11 prepared in advance using an adhesive may be used, or the adhesive may be sprayed or applied to the surface of the surface oxide film 2. You may form by doing. The bonded bodies 20 and 20A to 20C may be coated with press oil on the surfaces thereof before being formed into automobile members, similarly to the aluminum alloy plates 10 and 10A.

  In the joined bodies 20, 20 </ b> A to 20 </ b> C, although not shown, when an aluminum alloy plate 10, 10 </ b> A (first aluminum alloy plate 10 a, 10 Aa) having the surface oxide film 2 on both surfaces is used, Through the adhesive layer 3, it becomes possible to further join the aluminum alloy plate 10, 10A (first aluminum alloy plate 10a, 10Aa) or the second aluminum alloy plate 12.

≪Automobile parts≫
Next, the automotive member according to the present invention will be described.
Although not shown, the automobile member is manufactured from the above-described joined body 20, 20A to 20C. And the member for motor vehicles is a panel for motor vehicles, etc., for example. Moreover, the manufacturing method of the member for motor vehicles is although it does not specifically limit, A conventionally well-known manufacturing method is used. For example, the above-described joined body 20, 20 </ b> A to 20 </ b> C is subjected to a cutting process, a pressing process, or the like to manufacture a car member having a predetermined shape.
In addition, since the member for motor vehicles is manufactured from above-described joined body 20, 20A-20C, even if it exposes to a high temperature humid environment, the adhesive durability in an interface improves.

  Next, the aluminum alloy plate of the present invention will be specifically described by comparing an example that satisfies the requirements of the present invention with a comparative example that does not satisfy the requirements of the present invention.

  An aluminum alloy cold-rolled sheet (plate thickness: 1 mm) was produced by the above-described manufacturing method using a JIS standard 6022 standard (Mg: 0.55 mass%, Si: 0.95 mass%). . The 0.2% proof stress of this cold-rolled sheet was 230 MPa. And this cold-rolled board was cut | disconnected to length 100mm x width 25mm, and it was set as the board | substrate. The substrate was degreased with alkali, and the substrate was heat-treated to an actual temperature of 550 ° C., cooled, and then added to an aqueous solution containing 0.01 to 15% by mass of zirconium nitrate adjusted to a pH of less than 4 by adding nitric acid. By dipping at ˜80 ° C. for 2 to 20 seconds, an aluminum alloy plate having a surface oxide film in which the amount of zirconium, the amount of magnesium and the amount of nitrogen were controlled was formed on both surfaces of the substrate. Subsequently, it washed with water and dried and it was set as the test material (No. 1-13). However, the specimen (No. 1) was not immersed in an aqueous zirconium nitrate solution.

For the above test materials (Nos. 1 to 13), the content of zirconium (Zr), magnesium (Mg), nitrogen (N), halogen, and phosphorus in the surface oxide film was determined by high-frequency glow discharge optical emission spectrometry (GD-OES). (Holiba Joban Yvon, Model JY-5000RF)). The results are shown in Table 1.
In all of the test materials (Nos. 1 to 13), halogen and phosphorus were not detected, and when the total content of Mg, Zr, and N did not reach 100 atomic%, O, Al, and trace impurities were added. Contains.

Next, the following evaluation was performed using the test materials (No. 1 to 13). The results are shown in Table 1.
<Cohesive failure rate (adhesion durability)>
As shown in FIGS. 4 (a) and 4 (b), the end of two specimens (25 mm wide) having the same configuration was wrapped with a thermosetting epoxy resin adhesive at a wrap length of 13 mm (adhesion area: 25 mm × 13 mm). Adhesive A used here is a thermosetting epoxy resin adhesive (bisphenol A type epoxy resin amount 30-40%, with barium ferrite added), and adhesive B is a thermosetting epoxy resin adhesive (bisphenol A type). The amount of epoxy resin is 40 to 50%, and barium ferrite is not added. And it adjusted by adding a trace amount glass bead (particle diameter 150 micrometers) to an adhesive agent so that the film thickness of an adhesive bond layer might be set to 150 micrometers. 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 pulled at a speed of 50 mm / min with a tensile tester under the two test conditions of an initial stage and after being held for 10 days in a high-temperature and humid environment of 50 ° C. and 95% relative humidity. The cohesive failure rate of the adhesive was evaluated. The cohesive failure rate was determined by the following equation (1). In the formula (1), one side after the tension of the adhesion test body was a test piece A, and the other side was a test piece B.
Cohesive failure rate (%) = 100 − {(interface peel area of test piece A / bonding area of test piece A) × 1
00} + {(interface peel area of test piece B / bonding area of test piece B) × 100} (1)
Three test pieces were prepared for each test condition, and the cohesive failure rate was an average value of the three. Further, the evaluation standard is that the cohesive failure rate is less than 60% as bad “x”, 60% to less than 80% is slightly bad “Δ”, 80% to less than 90% is good “◯”, and 90% or more is excellent. “◎”.

  As shown in Table 1, the test material (No. 1) that was not immersed in the zirconium nitrate aqueous solution as a comparative example had a poor cohesive failure rate both at the initial stage and after high-temperature wetting. Moreover, the test material (No. 2) in which the Mg content and N content were controlled and the test material (No. 3) in which the Zr content and N content were controlled showed a slight improvement in the cohesive failure rate. However, depending on the type of adhesive, the improvement effect after high temperature wetting was not observed.

  On the other hand, the test materials (Nos. 4 to 11 and 13) as examples have good cohesive failure rates both in the initial stage and after high temperature wetness by appropriately controlling the Zr amount, Mg amount and N amount. The evaluation was “◯” or higher. Further, by controlling the amount of Zr and the amount of Mg within preferable ranges (sample materials (Nos. 6 to 9)), an excellent cohesive failure rate (“」 ”) was exhibited even after high temperature wetting. In addition, even when the amount of Zr and the amount of Mg are within the preferable ranges, when the amount of N exceeds the predetermined range (the test material (No. 12) which is a reference example), the cohesive failure rate after high temperature wetting is good. Stayed at "○". Therefore, it was confirmed that the adhesion durability was further stably improved by controlling the N amount.

  As described above, the aluminum alloy plate according to the present invention has been described in detail with reference to the embodiments and examples. However, the gist of the present invention is not limited to the above-described contents, and the scope of the right is described in the claims. Must be interpreted on the basis of Needless to say, the contents of the present invention can be modified and changed based on the above description.

1 Aluminum alloy substrate (substrate)
2 Surface oxide film 3 Adhesive layer 10, 10A Aluminum alloy plate 10a, 10Aa First aluminum alloy plate 11 Adhesive member 12 Second aluminum alloy plate 20, 20A, 20B, 20C

Claims (9)

An aluminum alloy substrate containing magnesium and a surface oxide film formed on the surface of the aluminum alloy substrate, the surface oxide film having a zirconium content of 0.01 to 10 atomic% and a magnesium content of 0.1 atom % And less than 10 atom%, and the amount of nitrogen is 6.9 atom% and less than 17 atom%.   The aluminum alloy plate according to claim 1, further comprising an adhesive layer made of an adhesive on the surface of the surface oxide film.   The surface oxide film has a ratio (Zr amount / Mg amount) of zirconium amount (Zr amount) to magnesium amount (Mg amount) of 0.0025 to 80, according to claim 1 or 2. The aluminum alloy plate as described.   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. The aluminum alloy plate according to any one of the above. The aluminum alloy plates according to claim 1 are joined bodies via an adhesive member made of an adhesive,
The adhesive member is bonded to the surface oxide film side of the two aluminum alloy plates, and each of the surface oxide films of the two aluminum alloy plates is arranged to face each other with the adhesive member interposed therebetween. A joined body characterized by. A joined body in which a second aluminum alloy plate made of an aluminum alloy is joined to a first aluminum alloy plate made of the aluminum alloy plate according to claim 1 via an adhesive member made of an adhesive,
The bonded body is characterized in that the adhesive member is bonded to the surface oxide film side of the first aluminum alloy plate. A bonded body in which the aluminum alloy plate according to claim 1 is bonded to the adhesive layer side of the aluminum alloy plate according to claim 2,
Each of the surface oxide films of the two aluminum alloy plates is disposed so as to face each other with the adhesive layer interposed therebetween. A joined body in which a second aluminum alloy plate made of an aluminum alloy is joined to the first aluminum alloy plate made of the aluminum alloy plate according to claim 2,
The second aluminum alloy plate is bonded to the adhesive layer side of the first aluminum alloy plate.   An automobile member manufactured from the joined body according to any one of claims 5 to 8.

Images