JP2023158363A - Aluminum member, and method of producing the same - Google Patents

Abstract

To provide a dyed aluminum member of low angle-dependency, and a method of producing the same.SOLUTION: An aluminum member 1 comprises: a substrate 10 formed of aluminum or an aluminum alloy; and an anode oxidation film 20 including a barrier layer 21 in contact with the surface of the substrate 10, a first porous layer 22 disposed on the opposite side of the barrier layer 21 with respect to the substrate 10, and a second porous layer 23 in contact with the opposite surface of the first porous layer 22 with respect to the barrier layer 21. The anode oxidation film 20 incorporates a dye compound, the first porous layer 22 comprises a plurality of branched pores, and the second porous layer 23 comprises a plurality of pores linearly extending in the lamination direction of the first porous layer 22 and the second porous layer 23.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to an aluminum member and a method for manufacturing the same.

In recent years, there has been an increasing demand for, for example, the housings of mobile devices and personal computers to have a white appearance. In order to meet such demands, attempts have been made to make the appearance of aluminum members white by forming an anodic oxide film on the surface of a base material formed of aluminum or an aluminum alloy.

Patent Document 1 states that the arithmetic mean height Sa of the surface of the base material is 0.1 μm to 0.5 μm, the maximum height Sz is 0.2 μm to 5 μm, and the average length RSm of the roughness curve element is Aluminum members are disclosed that are between 0.5 μm and 10 μm.

Patent No. 6525035

According to the aluminum member of Patent Document 1, by setting the arithmetic mean height Sa, maximum height Sz, and average length RSm of the roughness curve elements of the base material within predetermined ranges, the aluminum member has a white appearance. is obtained. By the way, as a method of imparting design properties to aluminum members, a method of dyeing anodized aluminum in various colors is known. However, the appearance of a dyed aluminum member may differ depending on the viewing angle due to the luster of the aluminum itself.

The present disclosure has been made in view of the problems that the conventional technology has. An object of the present disclosure is to provide a dyed aluminum member with low angle dependence and a method for manufacturing the same.

An aluminum member according to a first aspect of the present disclosure includes a base material formed of aluminum or an aluminum alloy, a barrier layer in contact with a surface of the base material, and a first layer disposed on the opposite side of the barrier layer from the base material. an anodic oxide film including a porous layer and a second porous layer in contact with a surface opposite to the barrier layer of the first porous layer, the anodic oxide film incorporates a dye compound, and the first porous layer has a plurality of branching pores, and the second porous layer has a plurality of pores extending linearly in the lamination direction of the first porous layer and the second porous layer.

A method for manufacturing an aluminum member according to a second aspect of the present disclosure includes a step of first anodizing a base material made of aluminum or an aluminum alloy with an electrolytic solution capable of forming a plurality of linearly extending holes; a second anodizing step of the first anodized base material with an electrolytic solution capable of forming a plurality of branching pores; an anodizing step of forming an anodized film on the surface of the base material; incorporating a dye compound into the film.

According to the present disclosure, it is possible to provide a dyed aluminum member with low angle dependence and a method for manufacturing the same.

It is a sectional view showing an example of the aluminum member concerning this embodiment. It is a figure showing an example of the manufacturing method of the aluminum member concerning this embodiment. It is a figure explaining the method of evaluating angle dependence using a spectrophotometer. It is a figure explaining the method of evaluating angle dependence using a goniophotometer. This is an image obtained by subjecting the cross section of the aluminum member of Reference Example 1 to FIB (focused ion beam) processing and magnifying it 2,550 times using a TEM (transmission electron microscope). This is an image obtained by subjecting the cross section of the aluminum member of Reference Example 1 to FIB processing and magnifying it 19,500 times using a TEM. This is an image obtained by subjecting the cross section of the aluminum member of Reference Example 1 to FIB processing and magnifying it 43,000 times using a TEM. This is an image obtained by subjecting the cross section of the aluminum member of Reference Comparative Example 1 to FIB processing and magnifying it 2,550 times using a TEM. This is an image obtained by subjecting the cross section of the aluminum member of Reference Comparative Example 1 to FIB processing and magnifying it 19,500 times using a TEM. This is an image obtained by subjecting the cross section of the aluminum member of Reference Comparative Example 1 to FIB processing and magnifying it 43,000 times using a TEM. This is an image obtained by subjecting the cross section of the aluminum member of Reference Comparative Example 2 to FIB processing and magnifying it 2,550 times using a TEM. This is an image obtained by subjecting the cross section of the aluminum member of Reference Comparative Example 2 to FIB processing and magnifying it 19,500 times using a TEM. This is an image obtained by subjecting the cross section of the aluminum member of Reference Comparative Example 2 to FIB processing and magnifying it 43,000 times using a TEM. These are the results of measuring the aluminum member of Reference Example 2 using GD-OES (glow discharge optical emission spectrometry). These are the results of measuring the aluminum member of Reference Comparative Example 3 using GD-OES. These are the results of measuring the aluminum member of Example 7 using GD-OES. These are the results of measuring the aluminum member of Comparative Example 7 using GD-OES. This is the result of measuring the aluminum member of Example 9 using GD-OES. These are the results of measuring the aluminum member of Comparative Example 9 using GD-OES. These are the results of measuring the aluminum member of Example 11 using GD-OES. These are the results of measuring the aluminum member of Comparative Example 11 using GD-OES.

Hereinafter, an aluminum member and a method for manufacturing the aluminum member according to the present embodiment will be described in detail with reference to the drawings. Note that the dimensional ratios in the drawings are exaggerated for convenience of explanation and may differ from the actual ratios.

[Aluminum member]
First, an aluminum member 1 according to the present embodiment will be explained using FIG. 1. As shown in FIG. 1, the aluminum member 1 includes a base material 10 and an anodic oxide film 20. As shown in FIG. These components will be explained below.

(Base material 10)
The base material 10 is formed of aluminum or an aluminum alloy. The base material 10 may be formed of, for example, a 1000 series alloy, a 2000 series alloy, a 3000 series alloy, a 4000 series alloy, a 5000 series alloy, a 6000 series alloy, a 7000 series alloy, or an 8000 series alloy. Examples of the 1000 series alloy include A1050, A1050A, A1070, A1080, A1085, A1100, A1200, A1N00, and A1N30 described in the JIS standard. Examples of the 2000 series alloy include A2011, A2014, A2014A, A2017, A2017A, A2024, and A2N01 described in the JIS standard. Examples of the 3000 series alloy include A3003, A3103, A3203, A3004, A3104, A3005, and A3105 described in the JIS standard. As the 4000 series alloy, A4032 described in the JIS standard can be exemplified. Examples of the 5000 series alloy include A5005, A5N01, A5021, A5052, 5N02, and A5042 listed in the JIS standard. Examples of the 6000 series alloy include A6101, A6061, A6005, A6N01, A6151, and A6063 described in the JIS standard. Examples of the 7000 series alloy include A7003, A7005, A7010, A7020, A7050, A7075A, and A7N01. Examples of the 8000 series alloy include A8021 and A8079 described in the JIS standard. The base material 10 is formed of aluminum or an aluminum alloy containing 0% by mass to 10% by mass of magnesium, 5% by mass or less of iron, and 13% by mass or less of silicon, with the balance being aluminum and inevitable impurities. It's okay. The base material 10 contains 0% to 10% by mass of magnesium, 5% by mass or less of iron, 13% by mass or less of silicon, and 10% by mass or less of zinc, with the balance being aluminum and unavoidable impurities. It may also be formed from certain aluminum or aluminum alloys. The base material 10 contains 0% to 10% by mass of magnesium, 5% by mass or less of iron, 13% by mass or less of silicon, and 10% by mass or less of copper, with the balance being aluminum and unavoidable impurities. It may also be formed from certain aluminum or aluminum alloys. The base material 10 contains 0% to 10% by mass of magnesium, 5% by mass or less of iron, 13% by mass or less of silicon, 10% by mass or less of copper, and 3% by mass or less of manganese. , and the remainder may be formed of aluminum or an aluminum alloy, which is aluminum and unavoidable impurities.

Although magnesium does not necessarily have to be contained in the base material 10, when the base material 10 contains magnesium, aluminum and magnesium form a solid solution, and the strength of the base material 10 can be improved. Further, by setting the magnesium content to 10% by mass or less, the strength of the base material 10 can be improved while suppressing a decrease in the corrosion resistance of the base material 10. The content of magnesium may be 0.5% by mass or more, or 1% by mass or more. Further, the content of magnesium may be 8% by mass or less, or 5% by mass or less.

Iron, manganese and silicon are difficult to form solid solutions with aluminum. Therefore, when the base material 10 contains these elements, these elements tend to precipitate in the anodic oxide film 20 as a second phase containing iron or silicon. When the anodic oxide film 20 contains such a second phase, part of the light that passes through the anodic oxide film 20 is absorbed by the second phase, so that the aluminum member 1 has a yellowish color. Sometimes it looks like The base material 10 may contain 3% by mass or less of iron. Further, the base material 10 may contain 2% by mass or less of manganese. Further, the base material 10 may contain silicon in an amount of 8% by mass or less.

Although zinc does not necessarily need to be contained in the base material 10, when the base material 10 contains zinc, the strength of the base material 10 can be maintained. Furthermore, by setting the zinc content to 10% by mass or less, the appearance of the aluminum member 1 is less likely to be impaired while maintaining the strength of the base material 10. The content of zinc may be 8% by mass or less.

The base material 10 may contain unavoidable impurities. In the present embodiment, unavoidable impurities refer to those present in raw materials or unavoidably mixed during the manufacturing process. Unavoidable impurities are essentially unnecessary impurities, but are allowed because they are in trace amounts and do not affect the properties of aluminum or aluminum alloys. Unavoidable impurities that may be contained in aluminum or aluminum alloys are elements other than aluminum, magnesium, iron, and silicon. The inevitable impurity may be an element other than zinc or an element other than copper. Unavoidable impurities that may be contained in aluminum or aluminum alloys include, for example, chromium, titanium, gallium, boron, vanadium, zirconium, lead, calcium, and cobalt. The total amount of unavoidable impurities in aluminum or aluminum alloy is preferably 0.5% by mass or less, more preferably 0.2% by mass or less, even more preferably 0.15% by mass or less, and 0. .10% by mass or less is particularly preferred. Further, the content of individual elements contained as unavoidable impurities is preferably 0.05% by mass or less, more preferably 0.03% by mass or less, and even more preferably 0.01% by mass or less. preferable.

The base material 10 may have irregularities on the surface 11 on the anodic oxide film 20 side. The aluminum member 1 can diffusely reflect the light that passes through the anodic oxide film 20 due to the unevenness formed on the surface 11. The unevenness on the surface 11 can be formed by a roughening treatment described below. The arithmetic mean height Sa of the surface 11 of the base material 10 on the anodic oxide film 20 side when the anodic oxide film 20 is removed may be 0.1 μm to 0.7 μm. Further, the maximum height Sz of the surface 11 of the base material 10 on the anodic oxide film 20 side when the anodic oxide film 20 is removed may be 25 μm to 50 μm. Furthermore, the average length RSm of the roughness curve elements of the surface 11 of the base material 10 on the anodic oxide film 20 side when the anodic oxide film 20 is removed may be 5 μm to 50 μm. When the anodic oxide film 20 is removed, the arithmetic mean height Sa of the surface 11 of the base material 10 on the anodic oxide film 20 side is 0.1 μm to 0.7 μm, the maximum height Sz is 25 μm to 50 μm, and , the average length RSm of the roughness curve elements may be 5 μm to 50 μm.

By setting the arithmetic mean height Sa to 0.1 μm or more, the light transmitted through the anodic oxide film 20 is diffusely reflected on the surface 11 of the base material 10, so that the angular dependence can be further improved. In addition, by setting the arithmetic mean height Sa to 0.7 μm or less, it is possible to suppress the light that has passed through the anodic oxide film 20 from being captured between the unevenness of the surface 11 of the base material 10. 1 can be suppressed from turning gray in appearance. The arithmetic mean height Sa may be 0.2 μm or more, or may be 0.3 μm or more. The arithmetic mean height Sa may be 0.4 μm or less. The arithmetic mean height Sa can be measured according to ISO25178.

By setting the maximum height Sz to 25 μm or more, the light transmitted through the anodic oxide film 20 is diffusely reflected on the surface 11 of the base material 10, so that the angular dependence can be further improved. Furthermore, by setting the maximum height Sz to 50 μm or less, it is possible to suppress the light that has passed through the anodic oxide film 20 from being captured between the unevenness of the surface 11 of the base material 10, so that the appearance of the aluminum member 1 can be reduced. can be prevented from turning gray. The maximum height Sz may be 30 μm or more. The maximum height Sz can be measured according to ISO25178.

By setting the average length RSm of the roughness curve element to 5 μm or more, the pitch of the unevenness on the surface 11 of the base material 10 does not become too small, so that the light transmitted through the anodic oxide film 20 can be transmitted to the surface 11 of the base material 10. It is possible to suppress capture between unevenness. Therefore, it is possible to further suppress the appearance of the aluminum member 1 from becoming gray. Further, by setting the average length RSm of the roughness curve elements to 50 μm or less, the pitch of the unevenness on the surface 11 of the base material 10 does not become too large. Therefore, the light transmitted through the anodic oxide film 20 is diffusely reflected on the surface 11 of the base material 10, and the angle dependence can be further improved. The average length RSm of the roughness curve elements may be 10 μm or more, or 15 μm or more. Moreover, the average length RSm of the roughness curve element may be 40 μm or less. The average length RSm of the roughness curve element can be measured according to JIS B0601:2013 (ISO 4287:1997, Amd.1:2009).

The arithmetic mean height Sa, maximum height Sz, and average length RSm of the roughness curve elements of the surface 11 of the base material 10 can be measured by removing the anodic oxide film 20 from the base material 10. Note that since the unevenness on the surface 11 of the base material 10 is smoothed by anodizing, the unevenness on the surface 11 of the base material 10 before anodizing is different from the unevenness on the surface 11 of the base material 10 after anodizing. There is a possibility that there may be. Therefore, in this embodiment, the shape of the surface 11 of the base material 10 after the anodic oxide film 20 is removed is measured. The method for removing the anodic oxide film 20 from the base material 10 is not particularly limited. For example, in accordance with JIS H8688:2013 (method for measuring mass per unit area of anodic oxide coatings on aluminum and aluminum alloys), the aluminum member 1 is immersed in a phosphoric acid chromic acid (VI) solution to dissolve and remove the anodic oxide coating 20. can do.

The shape and thickness of the base material 10 are not particularly limited and can be changed as appropriate depending on the application. Further, the base material 10 may be subjected to processing treatment, heat treatment, or the like.

(Anodized film 20)
Anodic oxide film 20 is provided on surface 11 of base material 10 . Such an anodic oxide film 20 can improve corrosion resistance, wear resistance, and the like. The thickness of the anodic oxide film 20 is not particularly limited, but is preferably 1 μm to 50 μm. By setting the thickness of the anodic oxide film 20 to 1 μm or more, corrosion of the base material 10 can be suppressed. Further, by setting the thickness of the anodic oxide film 20 to 50 μm or less, light absorption by the anodic oxide film 20 can be suppressed. The anodic oxide film 20 includes a barrier layer 21 , a first porous layer 22 , and a second porous layer 23 .

Barrier layer 21 is in contact with surface 11 of base material 10 . Barrier layer 21 is a dense non-porous layer. The thickness of the barrier layer 21 is not particularly limited, but may be, for example, 1 nm or more, or 10 nm or more. Moreover, the thickness of the barrier layer 21 may be 500 nm or less, or may be 300 nm or less.

Barrier layer 21 contains aluminum oxide. In addition to aluminum and oxygen, the barrier layer 21 may also contain elements derived from the components of the electrolytic solution used in the anodic oxidation. The element derived from the components of the electrolytic solution may be at least one element selected from the group consisting of sulfur, carbon, sodium, potassium, phosphorus, silicon, and nitrogen, which is a constituent element of ammonia.

The first porous layer 22 is disposed on the opposite side of the barrier layer 21 from the base material 10. In this embodiment, the first porous layer 22 is in contact with the surface of the barrier layer 21 opposite to the base material 10, but a third porous layer (not shown) is provided between the barrier layer 21 and the first porous layer 22. may be placed.

The first porous layer 22 has a plurality of branching pores. Each pore of the first porous layer 22 has a dendritic structure, and the first porous layer 22 is provided with a plurality of pores extending from the surface of the barrier layer 21 toward the second porous layer 23 while branching. Good too. The first porous layer 22 is provided with linear pores extending from the surface of the barrier layer 21 toward the second porous layer 23, and may be provided with pores branching from the linear pores.

The first porous layer 22 may have a plurality of pores having a larger average pore diameter than the second porous layer 23. When the pore size is increased, the voltage can be increased and the film formation rate can be increased. Further, the first porous layer 22 may have a plurality of pores having a smaller average pore diameter than the second porous layer 23. In addition, in this specification, the average pore diameter is an average value obtained by observing the cross section of the aluminum member 1 with a transmission electron microscope and measuring 10 or more pores.

The average pore diameter of the plurality of pores in the first porous layer 22 may be within the range of 5 nm to 350 nm. The average pore diameter of the first porous layer 22 may be 20 nm or more, or 50 nm or more. Moreover, the average pore diameter of the first porous layer 22 may be 300 nm or less, 200 nm or less, or 150 nm or less.

The thickness of the first porous layer 22 is not particularly limited, but may be 10 nm or more and 20,000 nm or less. By setting the thickness of the first porous layer 22 within the above range, diffuse reflection of light can be promoted. The thickness of the first porous layer 22 may be 50 nm or more, or 100 nm or more. The thickness of the first porous layer 22 may be 15,000 nm or less, or may be 10,000 nm or less.

The first porous layer 22 contains aluminum oxide. In addition to aluminum and oxygen, the first porous layer 22 may also contain components derived from the electrolyte solution for anodic oxidation. Components derived from the electrolyte include acids containing carboxyl groups such as sulfuric acid, phosphoric acid and their salts, oxalic acid, salicylic acid, citric acid, maleic acid and tartaric acid, and their salts, silicates, and ammonium salts. etc. Examples of salts include sodium salts and potassium salts.

The second porous layer 23 is in contact with the surface of the first porous layer 22 opposite to the barrier layer 21 . The second porous layer 23 is arranged as the outermost layer of the aluminum member 1 and may be exposed. The second porous layer 23 may be the outermost layer of the anodic oxide film 20.

The second porous layer 23 has a plurality of holes extending linearly in the lamination direction of the first porous layer 22 and the second porous layer 23. The second porous layer 23 may have a plurality of pores that are aligned and extend linearly from the surface in contact with the first porous layer 22 toward the exposed surface 24 . The pores of the second porous layer 23 may be continuous with the pores of the first porous layer 22.

The average pore diameter of the plurality of pores in the second porous layer 23 may be within the range of 1 nm to 200 nm. The average pore diameter of the second porous layer 23 may be 5 nm or more, or 10 nm or more. Further, the average pore diameter of the second porous layer 23 may be 100 nm or less, 50 nm or less, or 20 nm or less.

The thickness of the second porous layer 23 is not particularly limited, but may be 2 μm or more and 50 μm or less. By setting the thickness of the second porous layer 23 to 2 μm or more, interference colors of the anodic oxide film 20 formed on the base material 10 can be suppressed. By setting the thickness of the second porous layer 23 to 50 μm or less, dissolution during formation of the anodic oxide film 20 can be reduced. The thickness of the second porous layer 23 may be 5 μm or more, or 8 μm or more. Moreover, the thickness of the second porous layer 23 may be 25 μm or less, or may be 15 μm or less.

The second porous layer 23 contains aluminum oxide. Further, the second porous layer 23 may contain, in addition to aluminum oxide, a component derived from the electrolyte solution for anodization. Components derived from the electrolyte for anodizing include sulfuric acid, amidosulfuric acid, phosphoric acid and their salts, acids containing carboxyl groups such as oxalic acid, salicylic acid, citric acid, maleic acid and tartaric acid, and their salts, silicic acid Salts, ammonium salts, etc. may be used. Examples of salts include sodium salts and potassium salts. When the second porous layer 23 contains the above-mentioned components, the light transmittance of the second porous layer 23 becomes high, so that light diffused by the surface 11 of the base material 10 can easily pass through.

A dye compound is incorporated into the anodic oxide film 20. Thereby, the aluminum member 1 can exhibit a color resulting from the incorporated dye compound, and the degree of freedom in design can be increased. The dye compound may be incorporated into at least one of the first porous layer 22 and the second porous layer 23. The dye compound may be located within the pores of the first porous layer 22 or within the pores of the second porous layer 23. The dye compound may be disposed on the surface layer of the anodic oxide coating 20, including the surface 24. The dye compound may include at least one of an organic dye compound and an inorganic dye compound. The dye compound may contain, for example, the element nitrogen.

The organic dye compound may have at least one unsaturated atomic group selected from the group consisting of a nitro group, an azo group, a sulfo group, and a carbonyl group. Further, the organic dye compound may contain, for example, a nitrogen element. For example, the dye compound may have an azo group. The organic dye compound may have an aromatic ring. The organic dye compound may contain a transition metal element. The organic dye compound may contain at least one element selected from transition metal elements, or may contain two or more elements. The organic dye compound may contain at least one selected from the group consisting of chromium, cobalt, copper, nickel, and tin. For example, the dye compound may contain chromium.

The inorganic dye compound may contain a transition metal element. The inorganic dye compound may contain at least one element selected from transition metal elements, or may contain two or more elements. The inorganic dye compound may contain at least one selected from the group consisting of iron, cobalt, and copper. The inorganic dye compound does not need to have at least one unsaturated atomic group selected from the group consisting of a nitro group, an azo group, and a carbonyl group. The inorganic dye compound does not need to have an aromatic ring. Inorganic dye compounds include ammonium iron oxalate, iron oxalate, cobalt oxalate, copper oxalate, iron acetate, cobalt acetate, copper acetate, iron sulfate, cobalt sulfate, copper sulfate, iron chloride, cobalt chloride, copper chloride, phosphorus. It may contain at least one selected from the group consisting of iron acid, cobalt phosphate, and copper phosphate.

The plurality of pores in at least one of the first porous layer 22 and the second porous layer 23 may have a sealant containing an aluminum hydrate in which aluminum is hydrated. The sealant may contain a nickel compound. Furthermore, instead of sealing, coating may be performed with a transparent organic material, inorganic material, or composite material. Examples of coatings made of organic materials include resin coatings such as acrylic resins, urethane resins, and fluorine resins. Examples of inorganic material coatings include DLC (Diamond-like Carbon), sputtered films made by sputtering metals such as silicon, and Permeate (registered trademark) series manufactured by D&D Co., Ltd. Examples include inorganic coating films containing inorganic components. Examples of composite material coatings include coatings containing resin and inorganic substances.

The L ^* value, a* value, and b ^* value in the L ^* a ^* b ^* color system ^of the aluminum member 1 measured from the anodized film 20 side are not particularly limited. The L ^* value may be 0 or more, 10 or more, 20 or more, 30 or more, 40 or more, 50 or more, 60 or more, 70 or more, 80 or more, or 90 or more. The L ^* value may be 100 or less, 90 or less, 80 or less, 70 or less, 60 or less, 50 or less, 40 or less, 30 or less, 20 or less, or 10 or less. The a ^* value may be −90 to +90 or less. a ^* Values are -80 or more, -70 or more, -60 or more, -50 or more, -40 or more, -30 or more, -20 or more, -10 or more, 0 or more, 10 or more, 20 or more, 30 or more, 40 The number may be 50 or more, or 60 or more. a ^* Values are 80 or less, 70 or less, 60 or less, 50 or less, 40 or less, 30 or less, 20 or less, 10 or less, 0 or less, -10 or less, -20 or less, -30 or less, -40 or less, -50 Below, it may be -60 or less. The b ^* value may be −90 to +90 or less. b ^* Values are -80 or more, -70 or more, -60 or more, -50 or more, -40 or more, -30 or more, -20 or more, -10 or more, 0 or more, 10 or more, 20 or more, 30 or more, 40 The number may be 50 or more, or 60 or more. b ^* Values are 80 or less, 70 or less, 60 or less, 50 or less, 40 or less, 30 or less, 20 or less, 10 or less, 0 or less, -10 or less, -20 or less, -30 or less, -40 or less, -50 Below, it may be -60 or less. The L ^* value, a ^* value and b ^* value in the L ^* a ^* b ^* color system are in accordance with JIS Z8781-4:2013 (Colorimetry - Part 4: CIE 1976 L*a*b* color space) can be found. The L ^* value, a ^* value, and b ^* value can be measured using a colorimeter, etc., and are measured under conditions such as diffuse illumination vertical reception method (D/0), viewing angle 2°, and C light source. be able to.

The strength of the aluminum was measured by glow discharge optical emission spectrometry (GD-OES) while sputtering from the surface 24 of the aluminum member 1 to the part of the base material deeper than the interface between the base material 10 and the anodic oxide film 20, and the strength of the aluminum was determined to be the maximum strength. If the position at 98% is the interface, the sputtering start time is 0%, and the time when sputtering reaches the interface is 100%, then the minimum amount of nitrogen in the measurement time from 20% to 100% after the start of sputtering The ratio of maximum strength to strength may be 10 or more. In this case, the dye compound has a nitrogen element, and it can be expected that the dye compound will improve the design. Note that the time from 0% of the sputtering start time to 20% after the start of sputtering corresponds to the surface layer portion of the anodic oxide film and is excluded from measurement because there are many variations in strength.

The L ^* value, a ^* value and b ^* value of the aluminum member 1 measured from the anodized film 20 side in the L ^* a ^* b ^* color system are -15°, 15°, 25°, 45°, 75° and Measured at a detector angle of 110°, the difference between the value where L ^* is maximum and the value where L ^* is minimum is ΔL ^* , and the value where a ^* is maximum and a ^* is minimum The difference between the values is Δa ^* _, and the difference between the value where b ^* is maximum and the value where b ^* is minimum is Δb ^* , and (Δa ^* ) ² , (Δb ^* ) ² , and (ΔL ^* ) ² If ΔE is the square root of the sum of ΔE and ΔE, ΔE may be 110 or less. ΔE may be 110 or less, 100 or less, 90 or less, 80 or less, 70 or less, 60 or less, It may be 50 or less. The smaller the value of ΔE, the more the angle dependence can be improved. Therefore, the lower limit of the above ratio is 0.

When the reflection intensity on the anodized film 20 side is measured using a goniophotometer at a detector angle of -80 degrees to +20 degrees, the ratio of the maximum reflection intensity to the minimum reflection intensity may be 400 or less. The above ratio may be 200 or less, 100 or less, 50 or less, 20 or less, 10 or less, or 4 or less. good. The smaller the above ratio is, the more the angle dependence can be improved. Therefore, the lower limit of the above ratio is 1.

As described above, the aluminum member 1 includes the base material 10 made of aluminum or an aluminum alloy. The aluminum member 1 includes a barrier layer 21 in contact with the surface 11 of the base material 10, a first porous layer 22 disposed on the opposite side of the barrier layer 21 from the base material 10, and a barrier layer 21 of the first porous layer 22. has an anodic oxide film 20 including a second porous layer 23 in contact with the opposite surface. A dye compound is incorporated into the anodic oxide film 20. The first porous layer 22 has a plurality of branching pores. The second porous layer 23 has a plurality of holes extending linearly in the lamination direction of the first porous layer 22 and the second porous layer 23.

The second porous layer 23 has a plurality of linearly extending pores and therefore has high translucency, and most of the incident light reaches the first porous layer 22 without being absorbed by the second porous layer 23 . The first porous layer 22 has a plurality of branching pores. Therefore, the light that has passed through the first porous layer 22 is diffusely reflected by the first porous layer 22. The light reflected by the surface 11 of the base material 10 is further diffusely reflected by the first porous layer 22 and passes through the second porous layer 23. Therefore, it is estimated that the dyed aluminum member 1 of this embodiment has low angle dependence. The aluminum member 1 can be preferably used, for example, in the case of a smartphone, a personal computer, or the like.

[Method for manufacturing aluminum members]
Next, a method for manufacturing the aluminum member 1 according to this embodiment will be described. As shown in FIG. 2, the method for manufacturing the aluminum member 1 includes a roughening process S1, an etching process S2, an anodizing process S3, a dyeing process S6, and a sealing process S7.

(Surface roughening treatment step S1)
In the surface roughening treatment step S1, irregularities are formed on the surface 11 of the base material 10 formed of aluminum or aluminum alloy. Although the surface roughening treatment step S1 is not an essential step, the angular dependence of the aluminum member 1 can be further improved. The base material 10 forming the unevenness may be produced by, for example, preparing a molten metal containing a predetermined element, casting, extrusion, rolling, heat treatment, or the like. Moreover, the base material 10 forming the unevenness may be used as it is without any special surface treatment after casting, rolling, or heat treatment. Further, the base material 10 on which the irregularities are formed may be used by grinding with a milling machine, and polishing the surface 11 with emery paper, buffing, chemical polishing, electrolytic polishing, or the like. The surface 11 of the base material 10 on which the unevenness is formed may be polished to an arithmetic mean height Sa of less than about 100 nm. By setting the arithmetic mean height Sa of the surface 11 of the base material 10 to less than 100 nm, the brightness of the base material 10 becomes high.

The irregularities on the surface 11 of the base material 10 may be formed by, for example, blasting. In the blasting process, particles can collide with the surface 11 of the base material 10 to form irregularities. The method of blasting is not particularly limited, and for example, at least one of wet blasting and dry blasting can be used. In the step of forming the unevenness, the unevenness may be formed by colliding particles having an average particle diameter of 20 μm or less against the surface 11 of the base material 10. By setting the average particle diameter to 20 μm or less, light passing through the anodic oxide film 20 can be prevented from being absorbed by the unevenness of the surface 11 of the base material 10.

The average particle diameter of the blast-treated particles may be 15 μm or less, 12.5 μm or less, or 10.5 μm or less. On the other hand, the lower limit of the average particle diameter is not particularly limited, but may be 2 μm or more. By setting the average particle diameter to 2 μm or more, appropriate irregularities are formed on the surface 11 of the base material 10, so that the light that has passed through the anodic oxide film 20 can be diffused and reflected. Therefore, the angle dependence of the aluminum member 1 can be further improved. The average particle diameter of the blast-treated particles may be 5 μm or more. Note that the average particle diameter represents the particle diameter when the cumulative value of the particle size distribution on a volume basis is 50%, and can be measured by, for example, a laser diffraction/scattering method.

Examples of particles used in blasting include ceramic beads containing silicon carbide, boron carbide, boron nitride, alumina, zirconia, etc., metal beads containing stainless steel, steel, etc., resin beads containing nylon, polyester, melamine resin, etc. Examples include glass beads containing glass. In the case of wet blasting, particles can be mixed with a liquid such as water and sprayed onto the base material 10. Conditions such as the injection pressure and the total number of particles during the blasting process are not particularly limited, and can be changed as appropriate depending on the state of the base material 10 and the like. In the blasting process, particles may be caused to collide with the surface 11 of the base material 10 such that the incident angle is equal to or less than a predetermined value. The angle of incidence may be 60 degrees or less, 45 degrees or less, 30 degrees or less, 15 degrees or less, or 5 degrees or less.

The method for forming irregularities on the surface 11 of the base material 10 is not limited to blasting, and may be formed by other methods such as laser processing and etching using a surface roughening agent. In laser processing, unevenness is formed by irradiating the surface 11 of the base material 10 with laser light. The diameter, depth, pitch, etc. of the concave portions and convex portions on the surface 11 of the base material 10 can be adjusted by adjusting the spot diameter, wavelength, output, frequency and pulse width of the laser beam, the moving speed of the laser beam with respect to the base material 10, etc. can be changed by In the surface roughening treatment by etching treatment, for example, unevenness may be formed by etching treatment using a chemical containing fluoride such as Alsaten (registered trademark) OL-25 manufactured by Okuno Pharmaceutical Co., Ltd. The depth of the recesses and the height of the projections on the surface 11 of the base material 10 can be changed by adjusting the temperature, concentration, time, etc. of the etching solution.

(Etching process S2)
Although the etching step S2 is not an essential step, it can remove the corners of the unevenness on the surface 11 of the base material 10 formed in the roughening treatment step S1 and smooth the unevenness. Etching conditions are not particularly limited.

In the etching step S2, the roughened base material 10 may be etched using at least one of an acidic solution and an alkaline solution. As the acidic solution, for example, aqueous solutions such as hydrochloric acid, sulfuric acid, and nitric acid can be used. Further, as the alkaline solution, for example, an aqueous solution of sodium hydroxide, potassium hydroxide, sodium carbonate, etc. can be used. The concentrations of the acidic solution and the alkaline solution are not particularly limited, but when an aqueous sodium hydroxide solution is used, they may be, for example, 10 g/L to 100 g/L.

The etching time and etching temperature are not particularly limited either, and can be adjusted as appropriate depending on the state of the base material 10 and the etching solution. For example, the etching time is 5 seconds to 90 seconds, and the etching temperature is 40°C to 60°C.

(Anodizing step S3)
In the anodic oxidation step S3, an anodic oxide film 20 is formed on the surface 11 of the base material 10. The anodizing step S3 includes a first anodizing step S4 and a second anodizing step S5. In this embodiment, the anodic oxide film 20 is formed on the surface 11 of the base material 10 by the first anodizing step S4 and the second anodizing step S5, but the third anodizing film 20 is formed after the second anodizing step S5. One or more additional anodization steps may be performed, such as steps.

(First anodic oxidation step S4)
In the first anodic oxidation step S4, the base material 10 on which the irregularities are formed is first anodized with an electrolytic solution capable of forming a plurality of linearly extending holes. The electrolytic solution used in the first anodic oxidation is not particularly limited as long as it can form a plurality of straight holes in the second porous layer 23. The electrolytic solution may be, for example, an aqueous solution containing at least one electrolyte selected from the group consisting of sulfuric acid, amidosulfuric acid, phosphoric acid, salts thereof, acids containing carboxyl groups, and salts thereof. Examples of the acid containing a carboxyl group include at least one acid selected from the group consisting of oxalic acid, salicylic acid, citric acid, maleic acid, and tartaric acid. Among these, it is preferable that the electrolytic solution for the first anodization contains at least one selected from the group consisting of sulfuric acid, amidosulfuric acid, and a compound having a carboxyl group. The electrolytic solution for the first anodization is preferably an acidic electrolytic solution, and the pH of the electrolytic solution is preferably 0 to 2, for example. The concentration of the electrolyte in the electrolytic solution is, for example, 1 g/L to 600 g/L.

The conditions for the first anodic oxidation are not particularly limited and can be adjusted as appropriate depending on the state of the base material 10 and the like. The temperature of the electrolyte may be, for example, 0°C to 30°C. The current density may be, for example, 1 mA/cm ² to 50 mA/cm ² . The electrolysis time may be, for example, 3 minutes to 50 minutes.

(Second anodization step S5)
In the second anodic oxidation step S5, the first anodized base material 10 is second anodized using an electrolytic solution capable of forming a plurality of branching pores. The electrolytic solution for the second anodization may be an electrolytic solution capable of forming a plurality of pores having a larger average pore diameter than the plurality of linearly extending pores. The electrolytic solution for the second anodization may be an electrolytic solution capable of forming a plurality of pores having an average pore diameter smaller than the plurality of linearly extending pores. The electrolytic solution used in the second anodic oxidation step S5 is not particularly limited as long as it can form a plurality of branching pores in the first porous layer 22. The electrolytic solution may be an aqueous solution containing at least one electrolyte selected from the group consisting of compounds having a carboxyl group such as oxalic acid and tartaric acid, phosphoric acid, chromic acid, boric acid, and salts thereof. Among these, it is preferable that the electrolytic solution for the second anodic oxidation contains at least one selected from the group consisting of a compound having a carboxyl group, phosphoric acid, and salts thereof. For example, the electrolyte for the second anodization may be a tartrate aqueous solution. The electrolytic solution for the second anodization may contain at least one selected from the group consisting of sodium, potassium, and ammonia. The electrolyte for the second anodization may be an acidic or alkaline electrolyte. When the electrolyte for the second anodization is an alkaline electrolyte, the pH of the electrolyte is, for example, 9 to 14. In order to make the electrolytic solution alkaline, sodium hydroxide or the like may be mixed with the electrolytic solution. The concentration of the electrolyte in the electrolytic solution is, for example, 0.5 g/L to 300 g/L.

The conditions for the second anodic oxidation are not particularly limited and can be adjusted as appropriate depending on the state of the base material 10 and the like. For example, the temperature of the electrolyte may be, for example, 0°C to 40°C. The voltage may be, for example, 2V to 500V. The amount of electricity per unit area may be, for example, 0.05 C/cm ² to 40 C/cm ² . The electrolysis time may be, for example, 0.1 minute to 180 minutes.

(Dyeing process S6)
In the dyeing step S6, a dye compound is incorporated into the anodic oxide film 20. In the dyeing step S6, the dye compound can be incorporated into the anodic oxide film 20 by bringing the anodic oxide film 20 into contact with the dye by immersion or the like. A dye compound may be incorporated into the anodic oxide film 20 by electrolytic coloring. As the dye compound, those mentioned above can be used.

Dyes include azo dyes, anionic dyes, anthraquinone dyes, basic dyes, carbonium dyes, quinoline dyes, quinone imine dyes, metal complex dyes, fluorescent dyes, acid dyes, direct dyes, natural dyes, reactive dyes, vat dyes, mordant dyes, It may contain at least one selected from the group consisting of phthalocyanine dyes, disperse dyes, methine dyes, sulfur dyes, and vat dyes. Note that examples of the azo dye include naphthol dyes. Examples of carbonium dyes include xanthene dyes such as rhodamine dyes, acridine dyes, and triphenylmethane dyes. Examples of quinoneimine dyes include oxazine dyes and thiazine dyes. Examples of vat dyes include leucoester dyes. Examples of methine dyes include cyanine dyes such as merocyanine dyes, azomethine dyes, and polymethine dyes.

The dye may include at least one of an organic dye and an inorganic dye. The organic dye is a dye containing the above-mentioned organic dye compound. The inorganic dye is a dye containing the above-mentioned inorganic dye compound. The organic dye may include at least one selected from the group consisting of chromate azo dyes, chromium complex azo dyes, and cobalt complex azo dyes. The inorganic dye may contain at least one of iron ammonium oxalate and cobalt acetate.

(Sealing process S7)
Although the sealing process S7 is not an essential process, the corrosion resistance of the aluminum member 1 can be improved by sealing the holes in the first porous layer 22 and the second porous layer 23. The sealing treatment can be carried out by a known method, for example, using high temperature water, high temperature steam, aqueous nickel acetate solution, nickel fluoride, silicate, or a combination thereof. Through the pore sealing treatment, aluminum hydrate, in which aluminum is hydrated, is generated within the pores.

As described above, the method for manufacturing the aluminum member 1 according to the present embodiment includes the anodizing step S3 of forming the anodic oxide film 20 on the surface 11 of the base material 10, and the step of incorporating a dye compound into the anodic oxide film 20. . The anodizing step S3 includes a step S4 of first anodizing the base material 10 made of aluminum or an aluminum alloy with an electrolytic solution capable of forming a plurality of linearly extending holes. The anodizing step S3 includes a step S5 of performing a second anodizing on the first anodized base material 10 using an electrolytic solution capable of forming a plurality of branching pores.

Since the above method includes the first anodizing step S4 and the second anodizing step S5, the anodic oxide film 20 including the barrier layer 21, the first porous layer 22, and the second porous layer 23 is formed. Therefore, the aluminum member 1 described above can be manufactured.

Hereinafter, the present embodiment will be described in more detail using Examples, Comparative Examples, Reference Examples, and Reference Comparative Examples, but the present embodiment is not limited thereto.

First, aluminum members according to Examples and Comparative Examples were produced.

[Example 1]
(Surface roughening treatment)
The base material was a rolled and annealed 5000-series aluminum alloy plate having a thickness of 3 mm and cut out to a length of 50 mm and a width of 50 mm. The 5000 series aluminum alloy contains 2.64% by mass of magnesium, 0.05% by mass of iron, 0.03% by mass of silicon, and 0.08% by mass of copper, with the balance being aluminum and inevitable impurities.

Particles were bombarded with the base material by dry blasting to form irregularities on the surface of the base material. The particles used were Fuji Random WA particle number 1200 (alumina particles, maximum particle size 27.0 μm, average particle size 9.5±0.8 μm) manufactured by Fuji Seisakusho Co., Ltd. After the blasting, the base material was degreased by immersing it in a 200 g/L nitric acid aqueous solution at room temperature (about 20° C.) for 2 minutes.

(etching)
The base material on which the unevenness was formed was etched by immersing it in a sodium hydroxide aqueous solution with a concentration of 50 g/L at a temperature of 50 °C for 1 minute, and then immersing it in a nitric acid aqueous solution with a concentration of 200 g/L for 2 minutes at room temperature (about 20 °C). smut was removed.

(First anodic oxidation)
The etched base material was immersed in a pH 0 acidic aqueous solution containing sulfuric acid at a concentration of 180 g/L, and subjected to first anodization under electrolytic conditions of a temperature of 18° C., a current density of 15 mA/cm ² , and an electrolysis time of 22 minutes.

(Second anodization)
The first anodized part was immersed in an alkaline aqueous solution at pH 13 containing disodium tartrate dihydrate at a concentration of 200 g/L and sodium hydroxide at a concentration of 3.5 g/L. Then, the above-mentioned member was subjected to second anodic oxidation under electrolytic conditions of a temperature of 5° C., a voltage of 160 V, a pressure increase rate of 1 V/sec, and an electrolysis time of about 3 minutes.

(staining)
The anodized parts were dyed using a dye solution prepared by dissolving red dye (TAC FIERY RED-GBM (Red105): chromium complex azo acid dye from Okuno Pharmaceutical Co., Ltd.) in water to a concentration of 3 g/L. , and stained for 5 minutes at 55°C.

(Sealing treatment)
The dyed member was sealed using a nickel acetate sealant (trade name: Sealing X, manufactured by Hanami Chemical Co., Ltd.). The sealing conditions were a sealing agent concentration of 33 mL/L, a sealing temperature of 95° C., and a sealing time of 20 minutes. In this way, the aluminum member of this example was produced.

[Example 2]
An aluminum member was produced in the same manner as in Example 1, except that the base material was anodized without blasting.

[Example 3]
An aluminum member was produced in the same manner as in Example 1 except that a blue dye (TAC BLUE BRL (Blue507): organic dye manufactured by Okuno Pharmaceutical Co., Ltd.) was used instead of the red dye.

[Example 4]
An aluminum member was produced in the same manner as in Example 3 except that the base material was anodized without blasting.

[Example 5]
An aluminum member was produced in the same manner as in Example 1, except that a black dye (TAC BLACK-SLH-AN (Black415): chromium complex azo acid dye manufactured by Okuno Pharmaceutical Co., Ltd.) was used instead of the red dye.

[Example 6]
An aluminum member was produced in the same manner as in Example 5, except that the base material was anodized without blasting.

[Example 7]
An aluminum member was produced in the same manner as in Example 1, except that the anodized member was dyed at 55° C. for 10 minutes using a dye solution in which the above red dye was dissolved in water at a concentration of 10 g/L.

[Example 8]
An aluminum member was produced in the same manner as in Example 7 except that the base material was anodized without blasting.

[Example 9]
An aluminum member was produced in the same manner as in Example 3, except that the anodized member was dyed at 55° C. for 10 minutes using a dye solution in which the above blue dye was dissolved in water at a concentration of 10 g/L.

[Example 10]
An aluminum member was produced in the same manner as in Example 9 except that the base material was anodized without blasting.

[Example 11]
An aluminum member was produced in the same manner as in Example 5, except that the anodized member was dyed at 55° C. for 10 minutes using a dye solution in which the above black dye was dissolved in water at a concentration of 10 g/L.

[Example 12]
An aluminum member was produced in the same manner as in Example 11 except that the base material was anodized without blasting.

[Comparative example 1]
An aluminum member was produced in the same manner as in Example 1, except that the member subjected to the first anodization was dyed without performing the second anodization.

[Comparative example 2]
An aluminum member was produced in the same manner as in Example 2 except that the member subjected to the first anodization was dyed without performing the second anodization.

[Comparative example 3]
An aluminum member was produced in the same manner as in Example 3, except that the member subjected to the first anodization was dyed without performing the second anodization.

[Comparative example 4]
An aluminum member was produced in the same manner as in Example 4, except that the member subjected to the first anodization was dyed without performing the second anodization.

[Comparative example 5]
An aluminum member was produced in the same manner as in Example 5, except that the member subjected to the first anodization was dyed without performing the second anodization.

[Comparative example 6]
An aluminum member was produced in the same manner as in Example 6, except that the member subjected to the first anodization was dyed without performing the second anodization.

[Comparative Example 7]
An aluminum member was produced in the same manner as in Example 7 except that the member subjected to the first anodization was dyed without performing the second anodization.

[Comparative example 8]
An aluminum member was produced in the same manner as in Example 8 except that the member subjected to the first anodization was dyed without performing the second anodization.

[Comparative Example 9]
An aluminum member was produced in the same manner as in Example 9, except that the member subjected to the first anodization was dyed without performing the second anodization.

[Comparative Example 10]
An aluminum member was produced in the same manner as in Example 10, except that the member subjected to the first anodization was dyed without performing the second anodization.

[Comparative Example 11]
An aluminum member was produced in the same manner as in Example 11, except that the member subjected to the first anodization was dyed without performing the second anodization.

[Comparative example 12]
An aluminum member was produced in the same manner as in Example 12, except that the member subjected to the first anodization was dyed without performing the second anodization.

The color tone (L ^* value, a ^* value and b ^* value), surface properties (Sa, Sz and RSm), first porous layer average pore diameter, and second porous layer average of the aluminum member obtained as above. The pore size was evaluated as follows. The results are shown in Table 1. Furthermore, the angular dependence of the aluminum member was evaluated by colorimetry and reflection intensity. The results are shown in Tables 2 to 13.

(color tone)
Based on JIS Z8722, the color tone of the aluminum member was measured from the surface of the anodized film using a color difference meter CR400 manufactured by Konica Minolta Japan Co., Ltd., and the L ^* value, a ^* value, and b ^* value were determined. For the color tone, the illumination/light receiving optical system is diffuse illumination vertical reception method (D/0), the observation conditions are CIE 2° field of view color matching function approximation, the light source is C light source, and the color system is L ^* a ^* b ^* . It was measured with

(Arithmetic mean height Sa and maximum height Sz)
First, in accordance with JIS H8688:2013, the aluminum member obtained as described above was immersed in a phosphoric acid chromic acid (VI) solution to dissolve and remove the anodic oxide film. Next, the arithmetic mean height Sa and maximum height Sz of the surface of the anodized film side of the base material were determined according to ISO25178 using a three-dimensional white interference microscope Contour GT-I manufactured by Bruker AXS Co., Ltd. It was measured. The arithmetic mean height Sa and the maximum height Sz were measured under conditions of a measurement range of 60 μm×79 μm, an objective lens of 115 times, and an internal lens of 1 times.

(Average length RSm of roughness curve element)
First, in accordance with JIS H8688:2013, the anodic oxide film of the aluminum member obtained as described above was dissolved in a phosphoric acid chromic acid (VI) solution and removed. Next, the average length RSm of the roughness curve element on the surface of the anodized film side of the base material was determined according to JIS B0601:2013 using a three-dimensional white interference microscope Contour GT-I manufactured by Bruker AXS Co., Ltd. Measured according to the same method. The average length RSm of the roughness curve element was measured under the conditions of a cutoff λc of 80 μm, an objective lens of 115 times, an internal lens of 1 time, and a measurement distance of 79 μm.

(Average pore size)
A cross section of the aluminum member was observed using a transmission electron microscope, and the average pore diameter of the porous layer was measured.

(Angle dependence - colorimetry)
The L ^* value, a ^* value, and b ^* value were measured using a spectrophotometer CM-M6 manufactured by Konica Minolta Japan, Inc. Specifically, as shown in FIG. 3, the aluminum member 101 was irradiated with light from a light source so that the incident angle was 45°, and the angle at which the reflection angle was 45° was defined as the detector angle of 0°. The position closer to the light source than the detector angle of 0° is defined as the positive direction of the detector angle, and the L ^* value when the detector angle is -15°, 15°, 25°, 45°, 75°, and 110°, The a ^* and b ^* values were measured. Among the L ^* values, a ^* values, and b ^* values at -15°, 15°, 25°, 45°, 75°, and 110°, the value at which L ^* is maximum (L ^* max) and L ^* are The difference from the minimum value (L ^* min) is ΔL ^* , and the difference between the value where a ^* is maximum (a ^* max) and the value where a ^* is minimum (a ^* min) is Δa ^* _, the difference between the value at which b ^* became maximum (b ^* max) and the value at which b ^* became minimum (b ^* min) was defined as Δb ^* . Then, the square root of the sum of (Δa ^* ) ² , (Δb ^* ) ² , and (ΔL ^* ) ² was calculated as ΔE. Note that the light source for colorimetry was a D65 light source, and the observation condition was a 2° field of view.

(Angle dependence - reflection intensity)
The angle dependence of the aluminum member was evaluated using a goniophotometer (Model GP-2) manufactured by Nikka Densoku Co., Ltd. Specifically, as shown in FIG. 4, the aluminum member 101 was irradiated with light, and the intensity of the light received by the detector 102 was measured. The detector 102 is rotatably provided around the aluminum member 101 at a predetermined distance. A case where the detector 102 is placed at a position where the incident angle of the incident light 103 is 45 degrees and the reflection angle of the reflected light 104 is 45 degrees is defined as a detector angle of 0 degrees. The reflection intensity on the anodic oxide film side of the reflected light 104 reflected by the aluminum member 101 was measured at 0.5 degree intervals in the detector angle range of -80 degrees to +40 degrees. Then, the ratio of the maximum reflection intensity to the minimum reflection intensity (maximum reflection intensity/minimum reflection intensity) in the detector angle range of -80 degrees to +20 degrees was calculated.

As shown in Tables 2 to 13, compared to the case where only the first anodization was performed, the aluminum members subjected to the first anodization and the second anodization had smaller values of ΔE and reflection intensity ratio. From these results, it can be seen that the second anodic oxidation reduced the angle dependence and made it difficult for the appearance of the aluminum member to change depending on the viewing angle.

Next, aluminum members according to Examples 13 to 16 and Comparative Examples 13 to 16 were produced. Then, in the aluminum members obtained in each example, the arithmetic mean height Sa, maximum height roughness Sz, average length RSm of roughness curve elements, ΔE, and intensity ratio were evaluated in the same manner as above. Details and evaluation results of each example are shown in Table 14.

[Example 13]
Except that blasting was performed using Fuji Random WA particle number 800 (maximum particle size 38.0 μm, average particle size 14.0 ± 1.0 μm) manufactured by Fuji Seisakusho Co., Ltd. in place of particles with particle number 1200. An aluminum member was produced in the same manner as in Example 7.

[Comparative Example 13]
Comparison except that blasting was performed using Fuji Random WA particle number 800 (maximum particle size 38.0 μm, average particle size 14.0 ± 1.0 μm) manufactured by Fuji Seisakusho Co., Ltd. instead of particle number 1200. An aluminum member was produced in the same manner as in Example 7.

[Example 14]
Except that blasting was performed using Fuji Random WA particle number 1000 (maximum particle size 32.0 μm, average particle size 11.5 ± 1.0 μm) manufactured by Fuji Seisakusho Co., Ltd. in place of particles with particle number 1200. An aluminum member was produced in the same manner as in Example 7.

[Comparative example 14]
Comparison except that blasting was performed using Fuji Random WA particle number 1000 (maximum particle size 32.0 μm, average particle size 11.5 ± 1.0 μm) manufactured by Fuji Seisakusho Co., Ltd. instead of particle number 1200. An aluminum member was produced in the same manner as in Example 7.

[Example 15]
An aluminum member was produced in the same manner as in Example 7.

[Comparative Example 15]
An aluminum member was produced in the same manner as Comparative Example 7.

[Example 16]
Except that blasting was performed using Fuji Random WA particle number 2000 (maximum particle size 19.0 μm, average particle size 6.7 ± 0.9 μm) manufactured by Fuji Seisakusho Co., Ltd. instead of particle number 1200. An aluminum member was produced in the same manner as in Example 7.

[Comparative Example 16]
Comparison except that blasting was performed using Fuji Random WA particle number 2000 (maximum particle size 19.0 μm, average particle size 6.7 ± 0.9 μm) manufactured by Fuji Seisakusho Co., Ltd. instead of particle number 1200. An aluminum member was produced in the same manner as in Example 7.

As shown in Tables 14 to 17, Sa, Sz, and RSm tended to increase as the average particle diameter of the blast particles increased. However, regardless of which blast particles are used, the aluminum member subjected to the first anodization and the second anodization has a lower value of ΔE and reflection intensity ratio than the case of only the first anodization. It became smaller. These results show that even if Sa, Sz, and RSm change, the angle dependence is reduced by the second anodic oxidation.

Next, an aluminum member was prepared in the following manner in order to observe its cross section using a transmission electron microscope.

[Reference Example 1]
(Surface roughening treatment)
The base material was a rolled and annealed 5000-series aluminum alloy plate having a thickness of 3 mm and cut out to a length of 50 mm and a width of 50 mm. The 5000 series aluminum alloy contains 4.31% by mass of magnesium, 0.02% by mass of iron, and 0.02% by mass of silicon, with the balance being aluminum and inevitable impurities.

Particles were bombarded with the base material by dry blasting to form irregularities on the surface of the base material. The particles used were Fuji Random WA particle number 1200 (alumina particles, maximum particle size 27.0 μm, average particle size 9.5±0.8 μm) manufactured by Fuji Seisakusho Co., Ltd. After the blasting, the base material was degreased by immersing it in a 200 g/L nitric acid aqueous solution at room temperature (approximately 20° C.) for 3 minutes.

(etching)
The base material on which the unevenness was formed was etched by immersing it in a sodium hydroxide aqueous solution with a concentration of 50 g/L at a temperature of 60 °C for 60 seconds, and then immersing it in a nitric acid aqueous solution with a concentration of 200 g/L for 2 minutes at room temperature (approximately 20 °C). smut was removed.

(First anodic oxidation)
The etched base material was immersed in a pH 0 acidic aqueous solution containing sulfuric acid at a concentration of 180 g/L, and subjected to first anodization under electrolytic conditions of a temperature of 18° C., a current density of 15 mA/cm ² , and an electrolysis time of 11 minutes.

(Second anodization)
The first anodized part was immersed in an alkaline aqueous solution at pH 13 containing disodium tartrate dihydrate at a concentration of 106 g/L and sodium hydroxide at a concentration of 3 g/L. Then, the above member was subjected to second anodic oxidation under the electrolytic conditions of a temperature of 5° C., a voltage of 160 V, a pressure increase rate of 1 V/sec, and an electrolysis time of 180 seconds. In this way, the aluminum member of this example was produced.

[Reference Comparative Example 1]
The aluminum member of this example was produced in the same manner as Reference Example 1 except that the second anodic oxidation was not performed.

[Reference comparative example 2]
An aluminum member was produced in the same manner as in Reference Example 1 except that the first anodic oxidation was not performed, the voltage of the second anodic oxidation was 110 V, and the electrolysis time was 11 minutes.

Figures 5, 6, and 7 are images of the cross section of the aluminum member of Reference Example 1 subjected to FIB processing and magnified 2,550 times, 19,500 times, and 43,000 times, respectively, using a transmission electron microscope. . FIGS. 8, 9, and 10 are images of the cross-section of the aluminum member of Reference Comparative Example 1 processed by FIB processing and magnified 2,550 times, 19,500 times, and 43,000 times, respectively, using a transmission electron microscope. . Figures 11, 12, and 13 are images of the cross section of the aluminum member of Reference Comparative Example 2 subjected to FIB processing and magnified 2,550 times, 19,500 times, and 43,000 times, respectively, using a transmission electron microscope. . As shown in FIGS. 5 to 13, it can be seen that the first porous layer has a plurality of branching pores, and the second porous layer has a plurality of linearly extending pores. 5 to 13 and the results of elemental analysis by GD-OES (not shown), in the anodic oxide film of Reference Example 1, a barrier layer and a first porous layer derived from the second anodic oxidation are formed on the surface of the base material. I found out that It was also found that a second porous layer derived from the first anodic oxidation was formed on the surface of the first porous layer.

Note that also in the aluminum member of the above example, the second porous layer had a plurality of linearly extending holes, and the first porous layer had a plurality of branching holes. From the above results, it is clear that an aluminum member comprising a first porous layer and a second porous layer, the first porous layer having a plurality of branching pores, and a dye compound incorporated into the anodic oxide film has angle-dependent is found to be low.

Next, in order to confirm the state of the dye, the aluminum members of each example were measured by GD-OES. 14 to 21 show the GD-OES results of aluminum members according to Reference Example 2, Reference Comparative Example 3, Example 7, Comparative Example 7, Example 9, Comparative Example 9, Example 11, and Comparative Example 11. It is.

[Reference Example 2]
An aluminum member was produced in the same manner as in Example 7, except that the anodized member was sealed without being dyed.

[Reference Comparative Example 3]
An aluminum member was produced in the same manner as Comparative Example 7, except that the anodized member was sealed without being dyed.

From the results shown in FIGS. 14 and 16, as well as FIGS. 15 and 17, it was confirmed that in the aluminum member dyed with the red dye, Cr derived from the dye was present in the anodic oxide film. From the results shown in FIGS. 14 and 18, as well as FIGS. 15 and 19, it was confirmed that Cr was not present in the anodic oxide film of the aluminum member dyed with the blue dye. This is considered to be because the blue dye did not contain Cr to the extent that it could be confirmed. From the results shown in FIGS. 14 and 20, as well as FIGS. 15 and 21, it was confirmed that in the aluminum member dyed with the black dye, Cr derived from the dye was present in the anodic oxide film.

Furthermore, the nitrogen element contained in the dye was confirmed by GD-OES. Specifically, while sputtering the aluminum member from the exposed surface on the anodic oxide film side, the nitrogen intensity was measured at 0.2 second intervals. It is thought that the nitrogen strength is not stable in the surface layer of the anodic oxide film. Therefore, in order to confirm the state of the dye compound incorporated into the anodic oxide film, the interface between the base material and the anodic oxide film was set at a position where the aluminum strength was 98% of the maximum strength. Then, when the sputtering start time was set as 0% and the time when sputtering reached the interface was set as 100%, the nitrogen intensity was measured during the measurement time from 20% to 100% after the start of sputtering. Then, the ratio of the maximum intensity to the minimum intensity of nitrogen was calculated. That is, the time required from the start of sputtering until the strength of aluminum reaches 98% of the maximum strength corresponds to the sputtering time of the anodic oxide film portion. Further, the time after the aluminum strength reaches 98% of the maximum strength corresponds to the sputtering time of the base material. In this example, the anodic oxide film portion was analyzed using the nitrogen intensity value for the remaining 80% of the time, excluding the 20% surface layer. Moreover, for the minimum intensity and the maximum intensity, the average of the measured intensities from X seconds after the start of sputtering to X+1 seconds after the start of sputtering was used as the intensity at X seconds after the start of sputtering. For example, the intensity 200 seconds after the start of sputtering is the average value of the intensity after 200 seconds, 200.2 seconds, 200.4 seconds, 200.6 seconds, 200.8 seconds, and 201 seconds. . The results are shown in Table 18.

As shown in Table 18, compared with the undyed aluminum members of Reference Example 2 and Reference Comparative Example 3, dyed Example 7, Comparative Example 7, Example 9, Comparative Example 9, Example 11 and It was confirmed that the nitrogen strength of the aluminum member of Comparative Example 11 was high. Specifically, it was confirmed that the nitrogen strength of the dyed aluminum member was 10 or more. This shows that the dye compound containing nitrogen is incorporated into the dyed aluminum member.

Although this embodiment has been described above using examples and comparative examples, this embodiment is not limited to these, and various modifications can be made within the scope of the gist of this embodiment.

1 Aluminum member 10 Base material 11 Surface 20 Anodic oxide film 21 Barrier layer 22 First porous layer 23 Second porous layer

Claims (15)

A base material formed of aluminum or aluminum alloy,
a barrier layer in contact with the surface of the base material, a first porous layer disposed on a side of the barrier layer opposite to the base material, and a second porous layer in contact with a surface of the first porous layer opposite to the barrier layer. an anodized film including a porous layer;
Equipped with
A dye compound is incorporated into the anodic oxide film,
The first porous layer has a plurality of branching pores,
The second porous layer is an aluminum member having a plurality of holes extending linearly in the lamination direction of the first porous layer and the second porous layer. The aluminum member according to claim 1, wherein the a ^* value in the L ^* a ^* b ^* color system of the aluminum member measured from the anodic oxide film side is -90 to +90, and the b ^* value is -90 to +90. . While sputtering from the surface of the aluminum member to a base material part deeper than the interface between the base material and the anodic oxide film, the position where the aluminum strength is 98% of the maximum strength was determined by glow discharge emission spectrometry. The ratio of the maximum intensity to the minimum intensity of nitrogen in the measurement time from 20% to 100% after the start of sputtering, where the interface is defined as the sputtering start time, and the time when sputtering reaches the interface is 100%. The aluminum member according to claim 1 or 2, wherein is 10 or more. The aluminum member according to claim 1 or 2, wherein the dye compound has an azo group. 3. An aluminum member according to claim 1 or 2, wherein the dye compound comprises chromium. The L ^* value, a ^* value and b ^* value in the L ^* a ^* b ^* color system of the aluminum member measured from the anodic oxide film side were -15°, 15°, 25°, 45°, 75° and Measured at a detector angle of 110°, the difference between the value where L ^* is maximum and the value where L ^* is minimum is ΔL ^* , and the value where a ^* is maximum and a ^* is minimum The difference between the values is Δa ^* _, and the difference between the value where b ^* is maximum and the value where b ^* is minimum is Δb ^* , and (Δa ^* ) ² , (Δb ^* ) ² , and (ΔL ^* ) ² The aluminum member according to claim 1 or 2, wherein ΔE is 110 or less when the square root of the sum of ΔE and ΔE is 110 or less. Claim 1 or 2, wherein when the reflection intensity on the anodic oxide film side is measured using a goniophotometer at a detector angle of -80 degrees to +20 degrees, the ratio of the maximum reflection intensity to the minimum reflection intensity is 400 or less. 2. The aluminum member according to 2. When the anodic oxide film is removed, the arithmetic mean height Sa of the surface of the base material on the anodic oxide film side is 0.1 μm to 0.7 μm, the maximum height Sz is 25 μm to 50 μm, and the roughness The aluminum member according to claim 1 or 2, wherein the average length RSm of the curved elements is 5 μm to 50 μm. The aluminum member according to claim 1 or 2, wherein the first porous layer has a plurality of pores having a larger average pore diameter than the second porous layer. a step of first anodizing a base material formed of aluminum or an aluminum alloy with an electrolytic solution capable of forming a plurality of linearly extending pores; and a step of anodizing the first anodized base material with a plurality of branching pores. an anodizing step of forming an anodic oxide film on the surface of the base material;
Incorporating a dye compound into the anodic oxide film;
A method for manufacturing an aluminum member, including: The method for manufacturing an aluminum member according to claim 10, wherein the electrolyte for the first anodization is an acidic electrolyte, and the electrolyte for the second anodization is an acidic or alkaline electrolyte. The method for manufacturing an aluminum member according to claim 10 or 11, wherein the electrolytic solution for the second anodization contains at least one selected from the group consisting of a compound having a carboxyl group, phosphoric acid, and salts thereof. The method for manufacturing an aluminum member according to claim 10 or 11, wherein the electrolytic solution for the second anodization contains at least one selected from the group consisting of sodium, potassium, and ammonia. The method for manufacturing an aluminum member according to claim 10 or 11, wherein the electrolytic solution for the first anodization contains at least one selected from the group consisting of sulfuric acid, amidosulfuric acid, and a compound having a carboxyl group. The method for manufacturing an aluminum member according to claim 10 or 11, comprising the step of forming irregularities on the surface of the base material, and the base material on which the irregularities are formed is subjected to the first anodic oxidation.

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