TW201903216A - Aluminum laminate and method for producing same - Google Patents

Abstract

An aluminum laminate (10) comprises an aluminum substrate (1) having a first surface (1A); and an anodic oxide film (2) that is formed in contact with the first surface (1A) and has a second surface (2A), which is in a position that is separated from the first surface (1A) in a direction that intersects the first surface (1A). A surface layer that includes the first surface (1A) of the aluminum substrate (1) includes aluminum having a purity of 99.9 mass% or more, and 0.001 to 0.052 mass% of iron. The surface roughness Ra of the second surface (2A) of the anodic oxide film (2) is 20 nm or less. The mean width of profile elements RSm of the second surface (2A) of the anodic oxide film (2) is less than 30 [mu]m. The thickness of the anodic oxide film (2) in a direction that intersects the anodic oxide film is 9 to 26 [mu]m.

Description

Aluminum laminated body and manufacturing method thereof

The invention relates to an aluminum laminate and a method for manufacturing the same.

A natural oxide film is usually formed on the surface of aluminum. However, the natural oxide film is easily corroded by moisture or moisture. Therefore, an anodic oxide film is usually formed on the surface of an aluminum plate used in a corrosive environment that contains aluminum, such as moisture or moisture, to protect the surface from corrosion. The thicker the thickness of the anodized film, the higher the corrosion resistance of the anodized film.

On the other hand, aluminum plates can be used as reflective plates for lighting or as panels for design building materials. In such applications, an aluminum plate having higher gloss and higher total reflectance is required.

However, it was previously thought that the greater the thickness of the anodized film, the lower the gloss and total reflectance of the aluminum plate.

Japanese Patent Laid-Open No. 2008-174764 (Patent Document 1) discloses an aluminum material including a barrier-type anodized film having a thickness of 100 nm to 500 nm. In the above-mentioned Patent Document 1, it is described that if the thickness exceeds 500 nm, the influence of the anodic oxide film on absorption of visible light increases and the specular reflection is poor. Therefore, the thickness of the barrier-type anodic oxide film must be 500 nm or less. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2008-174764

[Problems to be solved by the invention]

The barrier-type anodic oxide film having a thickness of 500 nm or less described in Patent Document 1 cannot sufficiently prevent corrosion of an aluminum plate used in a corrosive environment containing a large amount of moisture or moisture around a kitchen or outdoors.

Moreover, in recent years, with the diversification of designs, an aluminum plate for a panel for a building material is required to have high image definition. However, the above-mentioned Patent Document 1 does not consider image sharpness.

Therefore, an object of the present invention is to provide an aluminum laminate having higher gloss, higher total reflectance, higher image sharpness, and higher corrosion resistance. [Technical means to solve the problem]

In order to solve the above-mentioned problems, the inventors and the like have made repeated efforts and found that the thickness of the anodic oxide film is extremely increased, and a kind of not only having higher corrosion resistance and surface hardness, but also having higher gloss and higher gloss can be obtained. Aluminum laminate with high total reflectance and high image sharpness.

That is, the aluminum laminated body of this embodiment has the following characteristics. The aluminum laminate according to this embodiment includes: an aluminum substrate having a first surface; and an anodized film formed by being connected to the first surface and having a distance from the first surface in a direction intersecting the first surface. The second side of the position. The surface layer including the first surface of the aluminum substrate contains aluminum having a purity of 99.9% by mass or more and iron of 0.001% by mass or more and 0.052% by mass or less. The surface roughness Ra of the second surface of the anodized film is 20 nm or less. The average inter-convex distance RSm of the second surface of the anodized film was less than 30 μm. The thickness of the anodized film in the crossing direction is 9 μm or more and 26 μm or less.

Conventionally, it has been known that as the thickness of the anodic oxide film increases, the positive reflectance of the aluminum laminate provided with it decreases. At this time, the regular reflectance does not decrease monotonically with the increase of the film thickness, but shows a tendency to gradually decrease while repeatedly decreasing and increasing the tendency. In FIG. 1 of the aforementioned Patent Document 1, if the thickness of the anodic oxide film is gradually increased from 0 nm to about 550 nm, the regular reflectance of the aluminum laminate gradually decreases and increases gradually while periodically Declining tendency. In the aforementioned Patent Document 1, based on this tendency, it was concluded that the thickness of the anodized film is preferably 150 nm ± 30 nm or 300 nm ± 20 nm. It is considered that the above-mentioned tendency occurs because the reflected light on the first surface of the aluminum substrate interferes with the reflected light on the second surface of the anodic oxide film.

In view of this situation, the present inventors have confirmed that, compared with an aluminum laminate having an anodic oxide film having a thickness of 150 nm to 300 nm, the inventor has an anodic oxide film having a thickness of 9 μm to 26 μm. The aluminum laminate of this embodiment has a high total visible light reflectance (for details, refer to the following examples). In addition, it was confirmed that aluminum laminates not only have higher gloss, total visible light reflectance, and image clarity than the aluminum laminates having an anodized film having a thickness of 600 nm or more and less than 9 μm. , And also has high corrosion resistance (for details, refer to the following examples). That is, the inventors have confirmed that within a relatively wide range of thickness values of the anodized film from 9 μm to 26 μm, higher gloss, higher total visible light reflectance, and higher maps can be achieved. Like sharpness.

The present inventors and others believe that, unlike the above-mentioned tendency that the regular reflectance caused by interference gradually decreases and decreases gradually, the above-mentioned tendency discovered this time is realized by a different action from the interference action.

In the aluminum laminate, the anodized film is a sulfuric acid anodized film. In the above-mentioned aluminum laminate, the total thickness of the aluminum substrate and the anodized film in the crossing direction is 60 μm or more and 1000 μm or less.

The manufacturing method of the above aluminum laminate includes the following steps: preparing an aluminum substrate having a surface roughness Ra of 15 nm or less on the first surface; and forming an intersecting direction on the first surface of the aluminum substrate using an electrolyte containing sulfuric acid The thickness of the anodized film is 9 μm or more and 26 μm or less. [Effect of the invention]

According to the present invention, an aluminum laminate having higher gloss, higher total reflectance, higher image sharpness, and higher corrosion resistance can be provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Moreover, in the following drawings, the same reference numerals are given to the same parts or equivalent parts, and the description is not repeated. [Configuration of Aluminum Laminate] As shown in FIG. 1, the aluminum laminate 10 of this embodiment includes an aluminum substrate 1 and an anodized film 2.

The aluminum base material 1 includes a first surface 1A and a third surface 1B located on the side opposite to the first surface 1A. The material constituting the aluminum substrate 1 includes aluminum (Al). The aluminum substrate 1 is, for example, an aluminum foil.

The aluminum purity of the surface layer including the first surface 1A of the aluminum base material 1 is 99.9% by mass or more.

The surface layer including the first surface 1A of the aluminum substrate 1 contains iron (Fe) in an amount of 0.001% by mass or more and 0.052% by mass or less. When the content of iron is less than 0.001% by mass, the strength of the aluminum substrate 1 is reduced. On the other hand, due to the low solid solubility of iron in aluminum, intermetallic compounds such as FeAl ₃ are easily crystallized during the casting of aluminum. Compared with the aluminum green body, these crystals have lower reflectance in the visible light region, which results in lower gloss and visible light reflectance when made into an aluminum substrate. In addition, if an intermetallic compound such as FeAl _{3 is} present, the anodized film becomes non-uniform, and not only the transparency of the anodized film is significantly deteriorated and the reflectance is reduced, but also the hardness of the anodized film is decreased. Therefore, the content of iron must be 0.052% by mass or less.

The surface layer including the first surface 1A of the aluminum base material 1 may also include, for example, silicon (Si) in an amount of 0.001% by mass or more and 0.09% by mass or less. The solid solubility of silicon in aluminum is large and it is difficult to form crystals. Therefore, as long as the content of silicon does not generate crystals, the reflectance in the visible light region will not be reduced. In addition, compared with the mechanical strength of the aluminum substrate 1 in which silicon is not solid-dissolved, the mechanical strength of the aluminum substrate 1 in which silicon is solid-dissolved in an amount of 0.001% by mass or more is enhanced by solid solution strengthening. Therefore, for example, the aluminum base material 1 with solid solution of 0.001% by mass or more of silicon can not only maintain the same mechanical strength as the aluminum base material 1 without solid solution of silicon, but can also be easily rolled into a thinner thickness Foil. On the other hand, when the aluminum substrate 1 contains more than 0.09% by mass of silicon, if the thickness of the anodized film 2 is increased, the transparency of the anodized film 2 decreases and the reflectance decreases. Further, the hardness of the second surface 2A of the anodized film 2 also decreases. Therefore, the content of silicon must be 0.09% by mass or less.

The rest of the surface layer of the aluminum substrate 1 including the first surface 1A other than Al, Fe, and Si contains impurities. The impurities are, for example, unavoidable impurities, but in addition to the unavoidable impurities, trace impurities that do not significantly affect gloss, total reflectance of visible light, image sharpness, and corrosion resistance may be included. The impurities include, for example, a material selected from the group consisting of copper (Cu), manganese (Mn), magnesium (Mg), zinc (Zn), titanium (Ti), vanadium (V), nickel (Ni), chromium (Cr), and zirconium (Zr). At least one element from the group consisting of boron (B), gallium (Ga), and bismuth (Bi). The content of each impurity element is 0.01% by mass or less.

The above-mentioned surface layer including the first surface 1A of the aluminum base material 1 is in a region (a depth direction) intersecting the first surface 1A from the first surface 1A by 5 μm. The surface roughness Ra of the first surface 1A is preferably 15 nm or less. More preferably, the surface roughness Ra of the first surface 1A is 10 nm or less. As a method for making the first surface 1A of the aluminum base material 1 have such a small surface roughness Ra, there are grinding processes such as physical grinding, electrolytic grinding, and chemical grinding, or cold rolling using a roll having a mirror surface. . The inventors have found that when the electrolytic polishing and chemical polishing are wet methods, and the surface roughness Ra before the first surface 1A is as high as 29 nm or more, the first surface is polished to a surface roughness Ra of 15 Below nm, the average inter-convex distance RSm also becomes 30 μm or more. In this case, the average inter-convex distance RSm of the second surface of the anodized film formed on the first surface will also be 30 μm or more, and the second surface does not have high image definition. The surface roughness Ra of the first surface 1A is preferably 15 nm or less by physical polishing or cold rolling. According to this method, even when the surface roughness Ra of the first surface 1A before polishing is 29 nm or more, the average inter-convex distance RSm and the surface roughness Ra can be suppressed by this method. Small abrasive surface. For example, when the surface roughness Ra of the first surface 1A of the aluminum substrate 1 is 10 nm or less by physical polishing or cold rolling, the average inter-convex distance RSm of the first surface 1A may be 20 μm or less. Therefore, the average inter-convex distance RSm of the second surface 2A of the anodized film 2 formed on the first surface 1A can be less than 30 μm, so the second surface 2A can have high image definition.

The composition of other parts of the aluminum base material 1 other than the above-mentioned surface layer is not particularly limited, and the aluminum base material 1 may also be constituted, for example, in the form of a covering material.

The anodized film 2 is formed by being connected to the first surface 1A. The anodic oxide film 2 includes a surface connected to the first surface 1A and a second surface 2A located away from the first surface 1A in a direction intersecting the first surface 1A. The anodized film 2 is formed by anodizing the first surface 1A of the aluminum substrate 1. The anodizing treatment may be any known anodizing method, and for example, anodizing treatment using an electrolytic solution containing at least any one of sulfuric acid, boric acid, oxalic acid, and phosphoric acid. The anodized film 2 is preferably formed by anodizing treatment using an electrolytic solution containing sulfuric acid. That is, the anodized film 2 is preferably a sulfuric acid anodized film. The anodized film 2 is preferably transparent.

The thickness of the anodized film 2 in the above-mentioned crossing direction is 9 μm or more and 26 μm or less. The thickness in the above-mentioned crossing direction of the anodized film 2 is the distance between the surface in contact with the first surface 1A and the second surface 2A in the anodized film 2. When the thickness of the anodized film in the above-mentioned cross direction is less than 9 μm, the reflected light of the light incident on the second surface of the anodized film on the first surface of the aluminum substrate and the incident light on the second surface The reflected light interferes. In this case, an interference color or white turbidity is generated on the second surface of the anodized film, and the aluminum laminate cannot achieve higher gloss, higher total reflectance of visible light, or higher image sharpness. When the thickness of the anodized film 2 in the above-mentioned cross direction is less than 9 μm, the corrosion resistance required for the aluminum laminate 10 that can be used outdoors can not be satisfied, and the surface hardness of the second surface 2A is also reduced.

On the other hand, when the thickness of the anodized film 2 in the above-mentioned cross direction is greater than 26 μm, the dissolution of the anodized film during the anodizing treatment will also be improved, so the film quality of the anodized film 2 is reduced, and the second surface 2A Reduced surface hardness.

Therefore, since the thickness in the above-mentioned cross direction of the anodized film 2 is 9 μm or more and 26 μm or less, the second surface 2A has not only higher gloss, higher total reflectance of visible light, and higher image clarity. Degree, and also has a high surface hardness.

The thickness of the anodized film 2 in the above-mentioned crossing direction is preferably 12 μm or more and 20 μm or less. The aluminum laminate 10 provided with such an anodic oxide film 2 not only improves productivity, but also has higher gloss, higher total reflectance and higher image sharpness on the second surface 2A, and has a higher Corrosion resistance.

The surface roughness Ra of the second surface 2A of the anodized film 2 is 20 nm or less. Part of the light incident on the aluminum laminate 10 is reflected on the second surface 2A of the anodized film 2, and the remaining part is refracted on the second surface 2A and reaches the first surface 1A of the aluminum substrate 1. When the surface roughness Ra of the second surface 2A of the anodized film 2 exceeds 20 nm, the light reflected on the second surface 2A or the light refracted on the second surface 2A may diffuse, resulting in the second surface 2A. Reduced gloss and total reflectance. If the surface roughness Ra of the second surface 2A of the anodized film 2 is 20 nm or less, the light reflected on the second surface 2A or the light refracted on the second surface 2A can be prevented from diffusing and the second surface can be diffused. 2A has higher gloss and higher total reflectance. In addition, the surface roughness Ra of the second surface 2A of the anodized film 2 is a three-dimensional expansion of the arithmetic average roughness Ra defined in JIS B0601 (2001 version) and ISO4287 (1997 version) so that it can be applied to surfaces. Calculated value.

The average inter-convex distance RSm of the second surface 2A of the anodic oxide film 2 was less than 30 μm. The average inter-convex distance RSm in any two directions orthogonal to each other in the second surface 2A is less than 30 μm. For example, when the aluminum base material 1 is manufactured through a rolling step, the average roughness distance RSm of the second surface 2A in the rolling direction (RD direction) of the aluminum base material 1 and the direction orthogonal to it (TD direction) is RSm. Less than 30 μm. When the average unevenness distance RSm of the second surface 2A of the anodized film 2 is 30 μm or more, the sharpness of the image on the second surface 2A decreases. If the average inter-convex distance RSm of the second surface 2A of the anodized film 2 is less than 30 μm, the second surface 2A has a higher image definition. In addition, the average distance between irregularities is based on the JIS standard JIS B0601 (2001 edition).

In order to set the surface roughness Ra and the average inter-convex distance RSm of the second surface 2A of the anodized film 2 to the above-mentioned numerical ranges, it is preferable to reduce the surface roughness Ra of the first surface 1A of the aluminum substrate 1. As described above, the surface roughness Ra of the first surface 1A of the aluminum substrate 1 is preferably 15 nm or less.

The total thickness of the aluminum substrate 1 and the anodic oxide film 2 in the above-mentioned crossing direction is preferably 60 μm or more and 1000 μm or less. If the total value is less than 60 μm, the thickness of the anodized film is larger than the thickness of the aluminum substrate. Therefore, the aluminum laminate becomes brittle and easily causes defects such as cracking. On the other hand, if the total value exceeds 1000 μm, the weight of the aluminum laminate is increased, which is not preferable. The total thickness of the aluminum substrate 1 and the anodic oxide film 2 in the intersecting direction is more preferably 100 μm or more and 800 μm or less. In order to obtain the total thickness of the aluminum substrate 1 and the anodized film 2 in the above-mentioned intersecting directions, the aluminum laminate 10 is within the above-mentioned numerical range, as long as the aluminum substrate obtained by casting and rolling according to a general manufacturing method is used. The material 1 may be anodized.

<The manufacturing method of an aluminum laminated body> Next, an example of the manufacturing method of the aluminum laminated body of this embodiment is demonstrated. As shown in FIG. 2, the method for manufacturing an aluminum laminate according to this embodiment includes the following steps: preparing an ingot (S10); homogenizing the ingot (S20); hot rolling the ingot (S30); Cold rolling is performed from the hot-rolled material obtained by hot rolling (S40); the cold-rolled material obtained by the cold rolling is subjected to cold rolling as a final process (hereinafter referred to as final cold rolling) to form an aluminum substrate (S50) ); And forming an anodized film (S60).

First, an ingot is prepared (step (S10)). Specifically, a molten aluminum having a specific composition is prepared, and the molten aluminum is solidified to cast (for example, semi-continuous casting) ingots. The content of metal elements such as Fe, Mn, and Si in the melt is controlled so that the purity of aluminum in the surface layer of the aluminum substrate 1 becomes 99.9% by mass or more. The content of Fe in the melt is controlled so that the content of Fe in the above-mentioned surface layer of the aluminum substrate 1 becomes 0.001% by mass or more and 0.052% by mass or less. The content of Si in the melt is preferably controlled so that the content of Si in the above-mentioned surface layer of the aluminum substrate 1 becomes 0.001% by mass or more and 0.09% by mass or less.

Then, the obtained ingot is subjected to a homogenization heat treatment (step (S20)). The homogenization heat treatment may be performed within a range of normal operating conditions, and for example, the heating temperature is set to 400 ° C or higher and 630 ° C or lower, and the heating time is set to 1 hour to 20 hours.

Then, the ingot is hot-rolled (step (S30)). Through this step, a hot-rolled material having a specific thickness W1 can be obtained. Hot rolling can be performed once or multiple times. Furthermore, in the case of manufacturing an aluminum ingot of a thin plate by continuous casting, the thin plate-shaped ingot may be directly cold-rolled without going through this step.

Next, the hot-rolled material obtained by hot rolling is cold-rolled (step (S40)). Through this step, a cold-rolled material having a specific thickness W2 (the material to be rolled in the final cold-rolling step (S50)) can be obtained. In this step, the cold rolling is performed a plurality of times, for example, by an intermediate annealing step. For example, first, the first cold rolling step (S40A) is performed on the hot-rolled material to form a rolled material that is smaller than the thickness W1 of the hot-rolled material and larger than the thickness W2 of the cold-rolled material. Then, the obtained rolled material is subjected to an intermediate annealing step (S40B). The intermediate annealing may be performed within a range of normal operating conditions. For example, the annealing is performed under conditions that the annealing temperature is 50 ° C or higher and 500 ° C or lower, and the annealing time is 1 second or longer and 20 hours or shorter. Then, a second cold rolling step (S40C) is performed on the annealed rolled material to form a cold rolled material having a thickness W2.

Then, the cold-rolled material is subjected to final cold-processing (step (S50)). In this step, the material to be rolled is cold-rolled by final processing using rolling rolls. The rolling roll has a roll surface that is rolled in contact with the material to be rolled. It is preferable that the surface roughness Ra of the roll surface of at least one of the pair of rolling rolls disposed across the rolled material is 50 nm or less. When the material to be rolled is rolled using a roll having a surface roughness greater than 50 nm, the surface roughness Ra of the first surface of the obtained aluminum substrate becomes 20 nm or more. The surface roughness Ra of the rolling roll used in this step is preferably as small as possible, and more preferably 40 nm or less. In this way, the aluminum substrate 1 is prepared.

Then, an anodized film 2 is formed on the first surface 1A of the obtained aluminum base material 1 (step (S60)). This step (S60) can be performed by a commonly known anodizing method. The anodizing treatment is performed by, for example, using at least one selected from the group consisting of a sulfuric acid bath, a boric acid bath, an oxalic acid bath, and a phosphoric acid bath as an electrolytic solution, immersing an aluminum substrate 1 as an anode therein, and immersing it in The other electrode in the electrolyte serves as a cathode, which energizes between these. Each condition of the anodizing method is such that the thickness of the anodized film 2 is 9 μm or more and 26 μm or less, the surface roughness Ra of the second surface 2A is 20 nm or less, and the average roughness distance RSm of the second surface 2A is not changed. The method up to 30 μm is appropriately selected. A sulfuric acid bath is preferably used as the electrolytic solution. In this way, the aluminum laminate 10 according to this embodiment shown in FIG. 1 can be obtained.

<Modifications> The surface layer including the first surface 1A of the aluminum base material 1 may not contain Si. As described above, Si contributes to improving the mechanical strength of the aluminum substrate 1. However, when the required mechanical strength can be secured by other parameters such as thickness, the aluminum substrate 1 may not contain Si. In this case, the total content of the above-mentioned impurities constituting the remainder other than Al and Fe in the surface layer of the aluminum substrate 1 including the first surface 1A may be 0.10% by mass or less.

As shown in FIG. 3, the aluminum laminate 11 may further include a second anodic oxide film 3 provided so as to be in contact with the third surface 1B of the aluminum substrate 1. The second anodized film 3 has a fourth surface 3B located at a position away from the third surface 1B in the crossing direction. That is, the aluminum laminate 11 includes an aluminum substrate 1 and an anodized film 2 and a second anodized film 3 which are provided so as to sandwich the aluminum substrate 1.

In the aluminum laminate 11, the surface layer including the third surface 1B of the aluminum substrate 1 is the same as the surface layer including the first surface 1A. The aluminum purity is 99.9% by mass or more, and includes 0.001% by mass or more and 0.052% by mass or less. iron. Such an aluminum base material 1 can be prepared by the same method as the above-mentioned steps (S10) to (S50) of the method for manufacturing the aluminum laminate 10 described above.

In the aluminum laminate 11, the second anodic oxide film 3 is the same as the anodic oxide film 2 described above, and the thickness in the cross direction is 9 μm or more and 26 μm or less, and the surface roughness Ra of the fourth surface 3B is 20 nm or less. The average inter-convex distance RSm of the fourth surface 3B is less than 30 μm. Such a second anodic oxide film 3 can be formed by the same method as the above-mentioned step (S60) of the method for manufacturing the aluminum laminate 10 described above. With regard to such an aluminum laminate 11, the second surface 2A of the anodized film 2 and the fourth surface 3B of the second anodized film 3 have higher gloss, higher total reflectance, and higher image clarity. .

In the aluminum laminate 11 described above, the composition of the surface layer including the third surface 1B of the aluminum substrate 1 may be different from the composition of the surface layer including the first surface 1A, but it is preferably the same. For example, the aluminum base material 1 may have a composition including a surface layer including a first surface 1A and a surface layer including a third surface 1B like a coating material, and a composition of the intermediate layer sandwiched therebetween.

As shown in FIG. 4, in the method for manufacturing the aluminum laminate, after the step (S50) and before the step (S60), the aluminum base material obtained by the final cold rolling can be ground. Step (S70). In this step (S70), the surface of the aluminum substrate to be the first surface 1A is polished to form the aluminum substrate 1 having the first surface 1A. In the manufacturing method of the aluminum laminate 11 described above, the surface to be the first surface 1A and the surface to be the third surface 1B are polished to form the aluminum substrate 1 having the first surface 1A and the third surface 1B. . The polishing processing method may be selected from physical polishing, electrolytic polishing, chemical polishing, and the like, but is not limited thereto. Preferably, physical polishing is performed in this step (S70).

In the method for manufacturing an aluminum laminate, the step of shaping the aluminum substrate obtained by the final processing cold rolling into a specific shape may be performed after the step (S50) and before the step (S60). Alternatively, after the step (S60), the step of forming the aluminum laminates 10 and 11 obtained in the step (S60) may be performed. In addition, after the step (S60), a step of forming a film on at least one surface of the aluminum laminate 10, for example, on the third surface 1B of the aluminum substrate 1 may be performed. The material constituting the film is at least one selected from the group consisting of resin, metal, ceramic, and the like. The coating film is, for example, an adhesive layer. After the step of forming the coating film, a step of bonding the aluminum laminates 10 and 11 to other members or walls through the coating film may be performed. [Example]

Samples of the reflecting members of the examples and comparative examples of this embodiment are prepared as described below, and these glossiness, total reflectance, image clarity, and corrosion resistance are evaluated.

First, using aluminum having different aluminum purity and Fe content as shown in Tables 1 and 2, the aluminum substrates of Examples and Comparative Examples were produced according to the production steps shown below.

[Table 1]

[Table 2]

The ingot of aluminum obtained by DC casting is subjected to a homogenization heat treatment in a heating furnace. Thereafter, hot rolling was performed until the thickness became approximately 6.5 mm. The obtained hot-rolled material was cold-rolled several times until the thickness became a specific value. A plurality of cold-rolling systems were carried out with intermediate annealing at intervals, and aluminum substrates having the thicknesses shown in Tables 1 and 2 were produced.

Here, for Examples 1 to 10 and 13 and Comparative Examples 1 to 11, rolling was performed using a roll having a surface roughness Ra of 40 nm in the final processing cold rolling. For Examples 11 and 12 and Comparative Examples 12 and 13, rolling was performed using a rolling roll having a surface roughness Ra of 50 nm in the final processing cold rolling. For Comparative Examples 14 to 21, rolling was performed using a roll having a surface roughness Ra of 100 nm in the final working cold rolling. For Comparative Examples 22 to 25, rolling was performed using a rolling roll having a surface roughness Ra of 150 nm in the final working cold rolling.

Furthermore, for Examples 9, 10 and Comparative Examples 10, 11, 18 to 21, the surface to be the first surface of the aluminum base material obtained by the final cold rolling (the surface rolled by the roll) For electrolytic polishing. The electrolytic polishing was performed by immersing the above-mentioned aluminum substrate at a current density of 2000 A / m ² for 20 minutes in an aqueous solution containing a bath temperature of 70 ° C. of phosphoric acid and 20 vol% of sulfuric acid.

In addition, for each sample, the homogenization heat treatment was performed under the conditions that the heating temperature was 400 ° C. to 630 ° C. and the heating time was 1 hour to 20 hours. For each sample, the intermediate annealing is performed under conditions such that the annealing temperature is 50 ° C. to 500 ° C. and the annealing time is 1 second to 20 hours.

With respect to the obtained aluminum substrate, the surface roughness Ra and the average distance between irregularities RSm of the first surface were measured. The measurement results are shown in Tables 3 and 4. In addition, the measurement method of the surface roughness Ra and the average distance between irregularities of the first surface of each aluminum substrate is measured by measuring the surface roughness Ra and the average distance between irregularities of the second surface of the aluminum laminate described below. The same method.

[table 3]

[Table 4]

As shown in Table 3, the surface roughness Ra of the first surface of the aluminum substrate of each example in which cold rolling was performed using a roll having a surface roughness Ra of 50 nm or less was 15 nm or less. Up to 30 μm. Table 4 shows the surface roughness Ra of the first surface of the aluminum substrate of each comparative example. As shown in Table 4, the surface roughness Ra of the first surface of Comparative Examples 18 to 21 in which cold rolling was performed using a roll having a surface roughness Ra of 100 nm and electrolytic polishing was performed was 15 nm or less. The average inter-concave-convex distance RSm of the first surface is 30 μm or more, and particularly exceeds 60 μm in a direction (TD) perpendicular to the rolling direction.

The aluminum substrate obtained in the above manner was subjected to anodizing treatment. The electrolytic solution was an aqueous solution containing a bath temperature of 21 ° C. containing 15% by volume of sulfuric acid. Each sample was immersed in the electrolytic solution as an anode, and a current with a current density of 130 mA / m ² was allowed to flow between the anode and the cathode for a specific time to perform an anodizing treatment. The anodic oxidation treatment time of each sample is set to the time to obtain an anodized coating layer of a specific thickness. That is, the anodizing conditions for each sample are the same except for the anodizing time.

Furthermore, the sealing treatment was performed on all samples under the same conditions. Sealing treatment is performed by immersing each sample formed with an anodized film in an aqueous solution at a bath temperature of 90 ° C. containing nickel acetate at a concentration of 5 g / L and boric acid at a concentration of 5 g / L, and then at a temperature of 98. It was immersed in pure water at 20 ° C for 20 minutes.

Each sample produced in this manner was evaluated according to the following evaluation method. <Evaluation method> The thickness of the anodized film obtained was measured using an eddy current film thickness meter ISOSCOPE FMP10 manufactured by Fischer Instruments and measured with an FTA3.3H probe. The thickness of the obtained aluminum laminate was measured using a digital micrometer MDC-MX IP65 manufactured by Mitutoyo Co., Ltd.

The observation of the surface asperity using an atomic force microscope was performed using a scanning probe microscope AFM5000II manufactured by Hitachi High-Tech Science Co., Ltd., using a dynamic force mode (non-contact) for a rectangular field of view of 80 μm × 80 μm The lower surface shape is performed. With respect to the obtained observation results, the slope of the sample was corrected by calculating the slope of the sample by using the least square approximation method to obtain a curved surface and performing a cubic curved surface automatic slope correction to determine the surface roughness Ra. The surface roughness Ra is a value calculated by three-dimensionally expanding the arithmetic average roughness Ra defined in JIS B0601 (2001 version) and ISO4287 (1997 version) so as to be applicable to the entire surface being observed.

The average bump-to-bump distance RSm was measured using SURFCOM 1400D manufactured by Tokyo Precision Co., Ltd., and the arithmetic mean bump-to-bump distance RSm defined in JIS B0601 (2001 version) and ISO4287 (1997 version) was measured. The measurement category is roughness measurement, the shape removal is the least square straight line method, the evaluation length is 4 mm, the cut-off category is 2RC phase non-compensation, and the cut-off wavelength λc is set when the Ra obtained in this measurement does not reach 0.1 μm. 0.25 mm is measured at 0.1 mm in the case of 0.1 μm or more. The measurement was performed in two directions of a rolling direction (RD) and a direction perpendicular to the rolling direction (TD), and the values in each direction were evaluated.

The gloss was measured using a Gloss meter VG7000 manufactured by Nippon Denshoku Industries Co., Ltd., and the gloss was measured at a light incident angle of 60 °. The gloss was measured in two directions: the rolling direction (RD) and the direction perpendicular to the rolling direction (TD), and the values in each direction were evaluated. The higher the gloss, the more metallic luster can be obtained.

The total reflectance was measured using an ultraviolet-visible spectrophotometer V570 manufactured by JASCO Corporation, using a standard whiteboard Spectralon for integrating spheres manufactured by Labsphere as a reference, and measuring the integrating sphere method in the wavelength range of 250 nm to 2000 nm. Lower total reflectance. From the obtained total reflectance measurement values, an average value of visible light in a wavelength range of 400 nm to 800 nm was obtained. The total reflectance is measured in two directions: the rolling direction (RD) and the direction perpendicular to the rolling direction (TD). The average of these values is used to evaluate the total reflectance.

In the evaluation of image sharpness, the all-in-one gloss meter IQ3 manufactured by RHOPOINT INSTRUMENTS was used, and the DOI (Distinctness of Image) value according to ASTM D5767 was used to evaluate the image sharpness. The measurement was performed in two directions of a rolling direction (RD) and a direction perpendicular to the rolling direction (TD), and the values in each direction were evaluated.

The surface hardness was evaluated by Vickers hardness. The Vickers hardness of each of the obtained Examples and Comparative Examples with respect to the direction (depth direction) where the second surface intersected with respect to the anodized film was measured. The Vickers hardness is a Vickers hardness measurement test using a Vickers hardness tester HMV-1 manufactured by Shimadzu Corporation with a diamond indenter at a pressure of 490 mN for 5 seconds.

The corrosion resistance was evaluated by the CASS test according to the following. The CASS test is carried out under the test conditions described in JIS H8681-2 (1999 version). The test time is based on the application examples described in § 6.2.2 of JIS H8601 (1999 version). 32 hours. The evaluation is based on the standards described in JIS H8681-2 (1999 version). As described in JIS H8601 (1999 version), Section 6.3, a rating of 9 or more is considered acceptable (A in Tables 7 and 8). If the value is less than 9, it is regarded as unacceptable (F in Tables 7 and 8).

<Evaluation results> Table 5 to Table 8 show the evaluation results by the above evaluation method.

[table 5]

[TABLE 6]

[TABLE 7]

[TABLE 8]

Examples 1 to 13 are aluminum substrates having an aluminum purity of 99.9% by mass or more and containing 0.001% by mass or more and 0.052% by mass or less of iron. The thickness is 9 μm or more and 26 μm or less. The surface roughness Ra of the second surface is Below 20 nm, the average distance RSm between the RD direction and the TD direction on the second surface is less than 30 μm. Furthermore, the total thickness of the aluminum substrate and the anodized film of Examples 1 to 13 was 60 μm or more and 1000 μm or less. Such Examples 1 to 13 have a gloss of 63% or more in the RD direction and the TD direction, a total reflectance of visible light of 83% or more, and a DOI value of 80 or more in the RD direction and the TD direction, which has high gloss. Degree, higher total reflectance, and higher image sharpness. Furthermore, the Vickers hardness of Examples 1 to 13 is 300 HV or more, which is acceptable in the CASS test and has high corrosion resistance. Further, in Examples 1 to 13, it was not confirmed that the thickness of the anodized film increased in a range of 9 μm or more and 26 μm or less, and the gloss, total reflectance of visible light, and image sharpness tended to decrease.

On the other hand, the conditions for final cold rolling of Comparative Examples 1 to 11 are the same as those of Examples 1 to 10, but at least any one of the chemical composition of aluminum, the thickness of the aluminum substrate, the presence or absence of electrolytic polishing, and the thickness of the anodized film Different.

Comparative example 1 in which the aluminum substrate had an aluminum purity of 99.9% by mass or more, but the Fe content of the aluminum substrate was greater than 0.052% by mass did not reach 63%, and did not have a high gloss. The reason for this is considered to be that the first surface of the aluminum substrate of Comparative Example 1 crystallized a large amount of intermetallic compounds containing Fe, resulting in a decrease in the gloss of the aluminum substrate.

Comparative Examples 2 to 4 in which the aluminum purity of the aluminum substrate was less than 99.9% by mass and the Fe content of the aluminum substrate was greater than 0.052% by mass did not reach 63%, and the total reflectance of visible light did not reach 83%. High gloss and high total reflectance. Further, in Comparative Example 4 in which the thickness of the anodic oxide film was 9 μm or more and 26 μm or less, the DOI values in the RD direction and the TD direction were 80 or less, which did not have high image sharpness. The reason is believed to be that the first surface of the aluminum substrates of Comparative Examples 2 to 4 crystallized a large amount of intermetallic compounds containing Fe, which caused the gloss and total reflectance of the aluminum substrate to decrease, and the transparency of the anodized film was significantly reduced. . Furthermore, the Vickers hardness of the anodic oxide films of Comparative Examples 2 and 3 of which the thickness of the anodic oxide film was less than 9 μm was 290 HV or less, which failed the CASS test and did not have high corrosion resistance. The reason is considered to be that the above-mentioned crystals on the aluminum substrate cause the film quality of the anodic oxide film to become non-uniform, and that the anodic oxide film is not sufficiently thick.

Compared with Examples 6 to 8, only the thickness of the anodized film is different, and the Vickers hardness of Comparative Examples 5 to 8 whose thickness is less than 9 μm is 290 HV or less, which failed the CASS test and did not have a high level. Corrosion resistance. Furthermore, in Comparative Examples 5 and 6 in which the thickness of the anodic oxide film was 0.5 μm or less, the total reflectance of visible light did not reach 83%, and the total reflectance of visible light was not high. The reason is considered to be that the light incident on the second surface of the anodic oxide film reflects the light on the first surface of the aluminum substrate and the reflected light of the incident light on the second surface interferes.

Compared with Examples 6 to 8, only the thickness of the anodized film is different. The thickness of the comparative example 9 having a thickness exceeding 26 μm is Vickers hardness of 290 HV or less, the surface hardness is low, and it does not have sufficiently high corrosion resistance (resistant to Abrasion).

Compared with Examples 9 and 10, only the thickness of the anodized film is different, and the Vickers hardness of Comparative Examples 10 and 11 whose thickness is less than 9 μm is 290 HV or less, which failed the CASS test and did not have a high Corrosion resistance.

Compared with Examples 11 and 12, only the thickness of the anodized film is different, and the gloss in the TD direction of Comparative Examples 12 and 13 whose thickness is less than 9 μm is less than 63%, and the total reflectance of visible light is less than 83%. Does not have high gloss and high visible light total reflectance. The reason is considered to be that the light incident on the second surface of the anodic oxide film reflects the light on the first surface of the aluminum substrate and the reflected light of the incident light on the second surface interferes. Furthermore, the Vickers hardness of Comparative Examples 12 and 13 was 290 HV or less, which failed the CASS test and did not have high corrosion resistance.

The surface roughness Ra of the second surface of the anodic oxide film of Comparative Examples 14 to 17 exceeded 20 nm, and the average distance between irregularities of the second surface in the RD direction and the TD direction, RSm, was 30 μm or more. In Comparative Examples 14 to 17, the gloss in the RD direction and the TD direction did not reach 63%, and the total reflectance of visible light did not reach 83%. It did not have high gloss and high total reflectance of visible light. Furthermore, in Comparative Examples 14 to 17, it was confirmed that as the thickness of the anodic oxide film becomes larger, the DOI value in the TD direction tends to decrease. In Comparative Examples 15 to 17 in which the thickness of the anodized film was 7.2 μm or more, the DOI value in the TD direction was 80 or less, which did not have high image sharpness.

The surface roughness Ra of the second surface of the anodic oxide film of Comparative Examples 18 to 21 is 20 nm or less, but the average distance between irregularities of the second surface in the RD direction and the TD direction is RSm is 30 μm or more, especially the second surface is at The average inter-convex distance RSm in the TD direction is larger than the average inter-convex distance RSm in the TD direction, and is 57 μm or more. In Comparative Examples 18 to 21, the DOI value in the TD direction did not reach 80, and did not have high image sharpness. Furthermore, in Comparative Examples 18 to 21, it was confirmed that the smaller the thickness of the anodic oxide film, the lower the Vickers hardness tends to be. The Vickers hardness of Comparative Examples 18 and 19 in which the thickness of the anodized film was less than 9 μm was 290 HV or less, which failed the CASS test and did not have high corrosion resistance.

The surface roughness Ra of the second surface of the anodic oxide film of Comparative Examples 22 to 25 exceeded 74 nm, and the average distance between irregularities of the second surface in the RD direction and the TD direction RSm was 30 μm or more. In particular, the average inter-convex distance RSm of the second surface of Comparative Examples 22 to 25 in the TD direction was 300 μm or more. In Comparative Examples 22 to 25, the gloss in the RD direction and the TD direction did not reach 63%, the total reflectance of visible light did not reach 83%, and the DOI value in the TD direction was 80 or less. It did not have high gloss and high visible light. Total reflectivity and high image sharpness.

Based on the above results, it was confirmed that the present embodiment can provide an aluminum laminate having higher gloss, higher total reflectance, higher image sharpness, and higher corrosion resistance. The aluminum laminate according to this embodiment is particularly suitable for a lighting reflector or a panel for building materials used in a corrosive environment containing a large amount of moisture or moisture, such as around a kitchen or outdoors.

The embodiments and examples disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is not the above-mentioned implementation forms and examples, and includes all the amendments and changes within the scope which are disclosed in the scope of patent application and have the same meaning as the scope of patent application.

1‧‧‧ aluminum substrate

1A‧‧‧Part 1

1B‧‧‧3rd

2‧‧‧ the first coating

2A‧‧‧The second side

3‧‧‧ 2nd coating

3B‧‧‧Fourth side

4‧‧‧ substrate

10‧‧‧Reflecting member

11‧‧‧Reflective member

FIG. 1 is a schematic cross-sectional view showing a reflecting member according to this embodiment. FIG. 2 is a flowchart showing a method for manufacturing a reflecting member according to the present embodiment. FIG. 3 is a schematic cross-sectional view showing a modified example of the reflecting member of the present embodiment. FIG. 4 is a flowchart showing a modified example of the method for manufacturing a reflective member according to this embodiment.

Claims (4)

An aluminum laminate comprising: an aluminum base material having a first surface; and an anodized film formed on the first surface in contact with the first surface and located away from the first surface in a direction crossing the first surface. The second surface of the surface of the aluminum substrate; and the surface layer of the aluminum substrate including the first surface contains aluminum having a purity of 99.9% by mass or more and iron of 0.001% by mass or more and 0.052% by mass or less. The surface roughness Ra of the two surfaces is 20 nm or less, the average inter-convex distance RSm of the second surface of the anodized film is less than 30 μm, and the thickness of the anodized film in the cross direction is 9 μm to 26 μm. . The aluminum laminate according to claim 1, wherein the anodized film is a sulfuric acid anodized film. For example, the aluminum laminate of claim 1 or 2, wherein the total thickness of the aluminum substrate and the anodized film in the cross direction is 60 μm or more and 1000 μm or less. An aluminum laminated body manufacturing method, which is a method for manufacturing an aluminum laminated body as claimed in claim 1 or 2, comprising the steps of: preparing the above-mentioned aluminum substrate having a surface roughness Ra of 15 nm or less on the first surface; and On the first surface of the aluminum substrate, an anodic oxide film having a thickness of 9 μm or more and 26 μm or less in the crossing direction is formed using an electrolytic solution containing sulfuric acid.