JPS602693A - Surface treatment for patterning aluminum alloy - Google Patents

Abstract

PURPOSE:To form a beautiful colored film on the surface of an Al alloy with good operability by forming an underlying pattern on the Al alloy formed by extrusion then subjecting the alloy to an electrochemical pigmenting treatment including slack age hardening and oxide film reforming. CONSTITUTION:A desired underlying pattern is formed by a mechanical operation on the surface of an Al alloy after extrusion then the alloy is subjected to a slack age hardening treatment. An anodically oxidized film is thereafter formed on the surface of such Al alloy and in succession the alloy is subjected to AC electrolysis or DC electrolysis in a bath of an inorg. acid or org. acid to reform the anodically oxidized film to a double-film construction. The reformed oxide film is subjected to AC electrolysis or DC cathodic electrolysis in an electrolyte contg. an inorg. metallic salt, thereby forming a desired colored film thereon. A difference in the density of coloring is generated between the underlying pattern part and the background by the synergistic effect of the above-mentioned surface treating stages, by which the colored pattern having the beautiful woodgrain tone, printed tone, etc. and having resistance to corrosion and wear is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention provides a surface treatment method that can clearly produce various decorative patterns such as wood grain and print patterns on the surface of aluminum alloys (excluding pure aluminum) that have age hardening performance. In more detail, it is an extremely simple method to apply a mechanical operation, an age hardening treatment operation, and an electrochemical operation to the surface of an aluminum alloy. Patterning of aluminum alloys, which can produce a certain beautiful colored pattern and form a corrosion-resistant colored film, is related to a surface treatment method.

Conventional technology and its problems Conventionally, as a method of generating a colored pattern on the surface of an aluminum material using artificial age hardening treatment, there is a method described in Japanese Patent Application Laid-open No. 53
-83941 is known. This technology involves attaching a desired patterned sheet to the surface of an aluminum material, subjecting it to artificial age hardening under normal conditions, removing the patterned sheet before or after cooling, and then removing the patterned sheet from the aluminum material. L will be subjected to electrolytic coloring treatment as an anode.
This is a method of creating a colored pattern on the surface of an aluminum material. The generation mechanism of the colored pattern in this method is that during the age hardening process, heating causes a difference in the crystal structure between the areas where the patterned sheet is attached to the aluminum laminated material and the area where it is not attached. This creates a pattern during electrolytic coloring.

However, this technique has the following drawbacks.

α) Inside the age hardening furnace, the temperature is not necessarily uniform between the left and right, top and bottom, front and rear ends and the center, and there are temperature differences, making it difficult to control the pattern of the resulting product.

b) Since aluminum material has very good thermal conductivity, it is difficult to create a temperature difference between the part where the patterned sheet is attached and the part where it is not attached. Therefore, it is difficult to produce a colored pattern with clear shading differences, and it is also difficult to make small patterns such as spots, polka dots, and woodgrain patterns appear on an all-aluminum material.

C) The process of attaching and detaching the patterned sheet is necessary, and a patterned sheet must be prepared for each shape of the extruded shape, so the workability is extremely poor and the resulting product is The strike will be high.

Furthermore, as another method for forming a patterned oxide film, the method described in Japanese Patent Publication No. 43-6365 is known. This technology uses an aluminum alloy with a specially selected At-MrL-Mg alloy composition, stretches the aluminum alloy, applies special heat treatment during or after the processing process, and then anodizes the aluminum alloy. This is a method of producing a contrasting black and white pattern on the aluminum alloy surface due to the precipitation of the kl-Mn binary compound.

The patterns obtained by this method are completely random in form, and as well as being able to obtain arbitrary patterns, the patterns are also limited to the contrast of black and white, making it possible to create decorative and beautiful colored patterns. The problem is that it still cannot be obtained.

OBJECTS OF THE INVENTION Accordingly, it is an object of the present invention to provide a surface treatment method for patterning aluminum alloys that is easy to work with and can produce beautiful wood grains and various desired colored patterns on the surface of aluminum alloys. .

Other objects of the present invention, in relation to the above-mentioned objects, are to produce a colored pattern that is excellent in various performances such as corrosion resistance, weather resistance, abrasion resistance, etc., and has good color contrast with differences in shading, and to produce a machined pattern for aluminum alloys. The object of the present invention is to provide a surface treatment method for patterning aluminum alloys that can impart mechanical strength through a series of steps with high productivity and energy efficiency.

Structure of the Invention The present invention provides a method of applying an incomplete age hardening treatment to an aluminum alloy after extrusion molding, after applying a base pattern by mechanical manipulation, instead of the conventional complete age hardening treatment after extrusion molding. By applying electrochemical coloring treatment including oxide film modification treatment to the aluminum alloy, the interaction between the base pattern portion and the ν pattern (portion other than the base pattern portion) is achieved by the mutual effect of each of these treatments. This is based on the knowledge that a difference in coloring density occurs between the layers, and the base pattern is clearly exposed on the surface of the aluminum alloy.

That is, the first aspect of the present invention is to apply a base pattern to the surface of an aluminum alloy after extrusion molding by mechanical operation.

(Bl) Next, the aluminum alloy is subjected to an incomplete age hardening treatment, (C) After aging, an anodized film is formed on the aluminum alloy by a conventional method, and tDl is then treated in an inorganic acid and/or organic acid bath. After the anodic oxide film is modified into a double film structure by alternating current electrolysis, the film is colored.

In addition, in a second invention according to the present invention, the oxide film modification step is different from the step 01 of the first invention, and (4) a base pattern is applied to the aluminum alloy surface after extrusion molding by mechanical operation, (Bl) Next, the aluminum alloy is subjected to incomplete age hardening treatment, (Q) Thereafter, an anodic oxide film is formed on the aluminum alloy by a conventional method, (6) This method employs a configuration in which an aluminum alloy is connected to a cathode and the oxide film is modified by direct current electrolysis, and then a coloring treatment is applied.

Aspects of the Invention Next, each step of the present invention and its aspects will be explained in detail.

(Al base pattern forming step) First, after extrusion molding (it may be an extruded shape at a high temperature of about 500 to 580°C immediately after extrusion, or it may be an extruded shape at room temperature that has been cooled after extrusion), aluminum alloy (hereinafter referred to as aluminum (hereinafter referred to as "alloy" for short) is subjected to a base pattern by mechanical manipulation.Mechanical manipulation includes all operations other than chemical treatment, such as etching with acid or alkali.

This base pattern can be applied by 1, for example, the plasto method in which sand, iron powder, etc. are sprayed, the high-pressure injection method in which water or other liquid is injected at high pressure, the brush method in which the aluminum alloy surface is scratched with a brush, the laser beam method in which laser beams are irradiated, and the embossed plate roll. It is applied to the surface of an aluminum alloy by various mechanical operation means such as a roller method using a mold press and a press method using a mold press.

To be more specific, for example, with the aim of improving workability,
Immediately after extruding the aluminum alloy, a mold or metal frame (jig) that has the same shape as the extrusion mold and has a certain clearance is provided with injection grooves (holes) for high-pressure injection at, for example, intervals in a straight-grain pattern, and a water bath is placed. The surface is continuously adjusted while spraying abrasives, etc.
In addition, it is possible to apply a base pattern even to uneven parts with complex shapes. In this case, a desired continuous pattern (for example, a pattern with long straight grain intervals as in printing, a pattern with varying shading, etc.) can be easily provided. In addition, instead of the above-mentioned high-pressure injection, metal or ceramic claw-shaped jigs are arranged inside the mold or metal frame arranged after the extrusion mold, for example, at intervals in a straight-grained pattern, and extrusion molding is performed with a constant pressure. A method of rubbing the later profile can also be adopted.

In addition, after the extruded aluminum alloy shape is cooled, it can be stamped into any desired pattern with a device 1 that gives scratches or distortions, such as an embossing plate roll, so that straight grain, plate grain, etc.
Desired patterns such as letters and pictures can be easily formed, and the decorativeness can be further enhanced. Furthermore, regarding panel relations.

It can also be stamped using a die press, allowing any complex pattern to be created.

In addition, as a method of mutual effect with the shape of the shape, we add irregularities in the shape of a pattern to the shape itself during the extrusion molding stage.

A pattern can also be imparted by rubbing the surface with metal, ceramic, carbon, etc. immediately after extrusion or after cooling.

The means for forming the base pattern is not limited to one or more methods, but any method may be used as long as it can form a decorative pattern on the surface of the aluminum alloy profile using a method with good workability.

The formation of this base pattern becomes the base or nucleus for the appearance of the colored pattern due to the interaction of the subsequent incomplete age hardening treatment and electrochemical coloring treatment, and the depth of the recess at the scratched area is adjusted by surface adjustment. It is not an essential element of (base pattern formation), but it is sufficient to have a die mark that is acceptable for appearance, and even after the oxide film is formed, no performance deterioration due to the scratches is observed even when observed under a microscope. It is to the extent that there is no such thing. Further, the same applies to the parts where distortion is applied, and there is no deterioration in performance at all.

1B) Incomplete age hardening treatment process Incomplete age hardening treatment is performed under conditions where the aluminum alloy does not reach complete aging.

To explain age hardening treatment, for example, aluminum alloy A
In the case of -60638 material, the effects of age hardening temperature and time on the hardness of the alloy are shown in FIG. That is, the hardness reaches its maximum value after a certain period of time at any temperature, and age hardening at this stage is defined as complete age hardening. Therefore, incomplete age hardening means age hardening before reaching this stage.

Although FIG. 1 shows the state of high-temperature aging or artificial aging, incomplete aging here is not limited to this, but also includes room temperature aging or natural aging. Therefore, to put it in the extreme, it may be allowed to dissipate for a long period of time and allow natural aging. However, it is usually preferable to perform artificial age hardening treatment from the point of view of workability, etc. In this case, although it differs depending on the material of the aluminum alloy, generally 10
It is recommended to do this for 10 minutes to 10 hours.

Figure 2 shows the appropriate range of time and temperature for incomplete age hardening treatment. In particular, the conditions within the shaded area in FIG. 2 are preferable.

(Q: Anodic oxide film formation process: 1) The aluminum alloy that has gone through each of the above steps is degreased, washed with water, and if necessary, smut removed, etc. using a normal method, and then 1) the aluminum alloy is subjected to a well-known anodic oxidation treatment to form an anodized film. Form.

That is, an electrolytic solution containing a well-known inorganic acid and/or organic acid, such as sulfuric acid, chromic acid, phosphoric acid, etc., or a mixed acid thereof, oxalic acid, malonic acid, etc., or a mixed acid containing these or a mixed acid with an inorganic acid, etc. The aluminum alloy is anodized using a 1M current or alternating current or a current waveform similar to these in a liquid.The applied voltage, application time, etc. for anodizing treatment are sufficient as usual.

(DJ, tni Oxide film modification process The oxide film on the aluminum alloy surface obtained as described above is modified by one of the methods described below.The oxide film modification treatment method includes alternating current electrolytic modification. There are a method and a cathodic direct current electrolytic reforming method, which correspond to the first invention and the second invention of the present application, respectively.

This oxide film modification treatment is a process carried out for the purpose of clearly expressing the contrast of the pattern, and the conditions for this are that the same electrolyte as the electrolyte used in the anodizing treatment or additives such as metal salts, which will be described later, are added to the electrolyte. An additional electrolyte or a different electrolyte may be used, and the electrolytic treatment is carried out in this electrolytic solution using alternating current or an equivalently effective waveform, or cathodic direct current electrolysis is carried out.

Each method will be explained below.

(DJ AC electrolytic reforming method) In an electrolytic solution consisting of an inorganic acid such as sulfuric acid, phosphoric acid, chromic acid, etc. By applying electricity, the oxide film is modified into a double film structure.

The electrolytic conditions are as usual and are sufficient, but preferably 5~
Testing is carried out at 30V for 1 to 30 minutes.

This secondary anodic oxidation treatment by AC electrolysis is not intended to produce a colored film, but in conjunction with the oxide film treatment described above, is to produce an oxide film with a double film structure.

Due to the formation of this double film structure, in the colored pattern formed in the subsequent coloring process, the difference in coloring shading between the underlying pattern and the background becomes remarkable, and the contrast of the colored pattern becomes clearer.

+nf Cathode direct current electrolytic reforming method In an electrolytic solution consisting of an inorganic acid such as sulfuric acid or phosphoric acid, the aluminum alloy on which the oxide film is formed is connected to the cathode to generate a direct current or a current waveform having properties equivalent to this. The aluminum alloy is electrically treated using the aluminum alloy.

This energization process causes a dissolution effect on the oxide film on the aluminum alloy surface, but at this time, because the current flow t is different between the base pattern part and other parts (background), there is a difference in the quality of the film between the two. Get out. As a result, the contrast of the colored pattern becomes more noticeable through the subsequent coloring process.

The concentration of the electrolytic solution, the applied voltage, the time, etc. are the same as in the conventional method, and the test is conducted under the conditions of 3 to 20 V and 20 seconds to 10 minutes.

(Coloring treatment step) The oxide film modified by either the Dl alternating current electrolytic reforming method or the six-cathode direct current electrolytic reforming method is then subjected to alternating current electrolysis in an electrolytic solution containing an inorganic metal salt! or direct current: cathodic electrolysis to form a colored film. Examples of inorganic metal salts include sulfates of nickel, cobalt, chromium, copper, cadmium, titanium, manganese, molybdenum, tin, magnesium, silver, lead, and hydrochloric acid. Various conventionally known salts such as salts, oxalates, tartrates, chromates, and phosphates can be used, and conventional electrolytic conditions are sufficient.

Through this coloring treatment, a colored film with excellent corrosion resistance, weather resistance, and various other properties is formed on the aluminum alloy surface, and the underlying patterned portion (P's or crooked portion) is made smaller than the background (non-patterned portion). The aluminum alloy is also darkly colored, and the underlying pattern applied to the aluminum alloy surface by mechanical manipulation appears as a colored pattern.

The aluminum alloy that has been colored in this manner is sent to a painting process as required, and is painted and baked by well-known methods. Depending on the alloy composition of the aluminum alloy, complete aging of the aluminum alloy may be difficult due to drying in a hot air oven after or before the anodic oxidation process, the oxide film modification process, and the coloring process. In some cases, baking after painting can reach full aging, so
It is preferable to perform painting/baking treatment. In addition, in such a case, one measure is to increase the aging hardness to a certain level in the baking furnace during the extrusion molding process of the aluminum alloy.

Material Although pure aluminum is excluded in the present invention, various aluminum alloys can be used. Aluminum alloy is an alloy that increases the machining strength during quenching and tempering, that is, the main additives are Cu and My+8i.

A preferred example is one containing Zn+Mg, but it is not limited to this, and the color tone of the colored pattern and the contrast of the pattern can be adjusted by combining the added elements, work hardening, heat treatment conditions, etc. In order to enhance the heat treatment effect and shorten the treatment time, we added an additional element i.
′ can also be changed. For example, At-M dar Si
age hardening can be promoted in the alloy of M or f3i-pg by combining the amounts of addition, for example by adding excess Si.

Therefore, for the purpose of improving color tone, pattern contrast, workability of processing steps, etc., it is possible to use an aluminum alloy having a cross-alloy component that meets the processing steps and conditions.

(16) Effects of the Invention As described above, the patterning of the aluminum alloy according to the present invention can be achieved by surface treatment methods including: (1) formation of a base pattern by mechanical operation, incomplete age hardening treatment, anodizing treatment, and oxide film modification. Due to the mutual action of each step of texture treatment and coloring treatment, a difference in color shading occurs between the base pattern portion and the background, which gives the aluminum alloy surface excellent performance such as corrosion resistance, weather resistance, and abrasion resistance. , woodgrain, pudding) can create various desired beautiful colored patterns. Of course, such effects are due to the mutual effects of the above-mentioned processes, and the fact that the oxide film modification process is added to 1% makes the contrast of the colored pattern clearer and the coloring. A colored pattern with extremely excellent properties can be obtained.

In addition, according to the method of the present invention, the colored pattern can be generated in a series of steps, and the base pattern can be formed continuously immediately after extrusion. Patterned surfaces can be treated. In addition, because the underlying pattern appears as a colored contrast pattern, the racking form in the surface treatment process can be either horizontal or vertical racking, and there is no need to add any new technology, and there are currently no standardized racking methods. This has the advantage that it can be dealt with in a sufficient manner.

In addition, the aluminum alloy shapes treated according to the present invention show no deterioration in performance even after being given a base pattern, no defects are observed even when observing the oxide film or colored film under a microscope, and electrolytic coloring is also observed in various tests. It is no different from the colored shapes made by the company, and can be used freely for the same purpose, without any restrictions on interior or exterior use.

Examples Example 1 After extrusion, the aluminum alloy (Jin-606383) shape was allowed to cool naturally. Thereafter, water was injected onto the surface of the aluminum alloy shape at 1200% using a high-pressure injection device. Form the base pattern and then heat at 175℃
Complete age hardening treatment was performed under the conditions of ×3 mmr. After that, the aluminum alloy shape is degreased, etched, and smut removed, and
? Immersed in W/V% sulfuric acid aqueous solution, current density 1.2A
/dm (voltage of about 12.5 V), liquid temperature of 21° C., and anodizing treatment for 35 minutes to form an anodized film of about 11 μm. Next, as an oxide film modification treatment, the counter electrode carbon was heated at the same concentration and temperature as the anodic oxidation bath at a current of 2.8 degrees/d (voltage approximately 7.8 V).
AC electrolysis was carried out for 7 minutes, and then, as a coloring treatment, a container with a length of 200+ u @ 150 m and a height of 150 mm with a carbon counter electrode placed at one end of the container was used as an electrolytic coloring device. Width 70cm, thickness 1.3cm
The above-mentioned aluminum alloy shape was set at a distance of 180 mm from the carbon counter electrode, and the temperature of the liquid consisting of the following composition was 1.
Immersed in electrolyte at 6°C, initial current density IA/d,
When AC electrolysis was carried out for 5 minutes at an applied voltage of 10 V, the base pattern was colored darker than the background, revealing a beautiful ocher decorative pattern.

Electrolyte bath composition: sulfuric acid 40 g/sodium trithionate + 9/s tin sulfate a f/1 Example 2 The oxide film modification treatment of Example 1 was carried out at a current density of IA/11!
The aluminum alloy profile was treated in exactly the same manner as in Example 1, except that the aluminum alloy profile was connected to the cathode and subjected to direct current electrolysis at a voltage of approximately 5 V for 2 minutes.
A beautiful ocher decorative pattern with a difference in shade between the base pattern on the surface of the shape and the background was revealed.

Example 3 After cooling an extruded aluminum alloy (A-60638) profile to room temperature, the surface of the aluminum alloy profile was heated at a rate of 1 Owx/'ec at a frequency of 3. O
A base pattern was formed by irradiating a laser beam of KI (z, +6A). Next, incomplete age hardening treatment was performed at 170°C x 3 hours, and after that, the aluminum alloy shape was
After degreasing, etching, and removing smut,
It was immersed in a sulfuric acid aqueous solution of E W/V %, and the current density was 1.
IA/dTf (voltage approximately +2V), liquid temperature 20℃, time 30
Anodic oxidation was carried out under conditions of 10 minutes to form an anodic oxide film of about 10 μm. Next, as an oxide film modification treatment, the aluminum alloy profile was connected to the cathode for 1 minute and 30 seconds at a current density of 1.2 A/d (voltage approximately 6 V) using the same equipment and the same concentration bath as in Example 2. DC electrolysis was performed. Next, as a coloring treatment, Example g
Using a device similar to the above, the bath temperature was 20°C with the following composition.
When it was immersed in an electrolytic solution and subjected to alternating current electrolysis for 5 minutes and 30 seconds at an applied voltage of IIVO, the underlying pattern was colored much darker than the background, resulting in a clear olive-colored decorative pattern.

Electrolyte composition: Sulfuric acid 20ml/L Nickel sulfate 30f/L Sulfuric acid No. 14 5P/L Cresol sulfonic acid IO/L Example 4 High temperature aluminum alloy (A-60638) immediately after extrusion
A base pattern was formed by bringing uneven carbon gold into contact with the surface of the shaped material, and the aluminum alloy shaped material was once cooled to room temperature, and then subjected to incomplete age hardening treatment under conditions of f160° C. x 7 hr.

After that, the aluminum alloy profile is degreased, etched, and smut removed, and then I'? It was immersed in a sulfuric acid aqueous solution of W/V%, and the current density was 1.2 A/d (voltage approximately fZ).
Anodizing was carried out under conditions of 5'l, liquid temperature of 21° C., and 35 minutes to form an anodic oxide film of about 11 μm. Subsequently, as an oxide film modification treatment, the same degree as the anodic oxidation treatment bath,
Under the same temperature conditions, current density 2.8) with counter electrode carbon
AC electrolysis was performed for 7 minutes at v/dTd (voltage: 7.8 V), and then, as a coloring treatment, using the same apparatus as in Example 1, the electrolyte was placed in an electrolytic solution having the following composition at a temperature of 20°C. When immersed and subjected to DC electrolysis with an applied voltage of 15 V for 2 minutes using the aluminum alloy shape as a cathode, the base pattern was colored considerably darker and blackish brown compared to the background, giving a clear bronze color. Displayed a decorative pattern.

(23) Electrolyte composition: Nickel sulfate 309/boric acid 20
9/ is ammonium sulfate 15P/1 pH 4,5 Example 5 In place of the base pattern forming treatment of Example 1, the wall thickness is approximately 0.11
A patterned embossed plate with irregularities of approximately 30 μm was made by etching the stainless steel plate from step 3, and this was placed on an aluminum alloy profile so that the pattern was in contact with the surface of the profile, and then a roller was placed over it. The aluminum alloy profile was treated in exactly the same manner as in Example 1, except that the base pattern was formed on the surface of the aluminum alloy by stamping. A beautiful decorative pattern with differences in shading was created.

Example 6 After cooling the aluminum alloy shape after extrusion molding, a stainless steel cut wire (grain size: rao) was injected from a nozzle with a diameter of 6.4 mm at an air pressure of 2 mm to form a base pattern. Next, the aluminum (24) alloy shape was subjected to incomplete age hardening treatment at 180°C for 2 hours, and then degreased, etched, and smut removed in the same manner as in Example 1, and the shape was heated at 17W/2 hours. Immersed in a sulfuric acid aqueous solution with a current density of 1.2 A/d (voltage 12.5 V) and a liquid temperature of 20°C.

Anodic oxidation was performed for 35 minutes to form an anodic oxide film of about 10.5 μm. Next, as an oxide film modification treatment, the aluminum alloy profile was connected to the cathode for 1 minute and 30 seconds at a current density of 1.2 A/d (voltage: 6 V) and DC electrolysis was performed.

Next, as a coloring treatment, the same container as in Example 1 was immersed in an electrolytic solution having the following composition at a bath temperature of 28°C.
When AC electrolysis was carried out for 3 minutes at an applied voltage of , only the sandblasted surface became blackish brown and -1,000.

The side that is not sandblasted becomes a dark brown color.

The result is a beautiful shape with different colors depending on the side of the shape.

Electrolyte set W: Nickel sulfate 25P/L magnesium sulfate 5F/Ammonium sulfate 30g/L Boric acid 20g/L Ammonium thiosulfate 1g/L pH 5.5 Comparative example I In Example 1, oxide film modification treatment When the same treatment as in Example 1 was performed except that , the color became pale yellow, and the underlying pattern was colored slightly darker than the background, but it was less clear than in Example 1.

[Brief explanation of the drawing]

Figure 1 is a graph showing the influence of age hardening temperature and treatment time on the hardness of aluminum alloy (A-60638), and Figure 2 is a graph showing the appropriate range of time and temperature for incomplete age hardening treatment. be. Applicant Yoshida Kogyo Co., Ltd. Agent Patent Attorney Masaaki Yonehara Patent Attorney Tadashi Hamamoto

Claims (1)

[Claims]! , (&l A base pattern is applied to the surface of the aluminum alloy after extrusion molding by mechanical manipulation. tBl Then, the aluminum alloy is subjected to an incomplete age hardening treatment. After forming an oxide film and modifying the anodic oxide film into a double film structure by performing alternating current electrolysis in an inorganic acid and/or organic acid bath. The patterning of aluminum alloy is a surface treatment method that has four characteristics that clearly express the base pattern on the aluminum alloy surface. 2 (4) Applying the base pattern by mechanical operation to the aluminum alloy surface after extrusion molding, iB) Next, the aluminum alloy is subjected to incomplete age hardening treatment. (C) After aging, an anodic oxide film is formed on the aluminum alloy in a conventional manner. (Dl) Subsequently, an inorganic acid and/or organic acid bath is applied. After the aluminum alloy is connected to a cathode in the aluminum alloy and the oxide film is modified by direct current electrolysis, the base pattern is clearly exposed on the surface of the aluminum alloy by applying coloring treatment. The patterning of aluminum alloy is a surface treatment method.