Aluminum alloy surface treatment method, aluminum alloy part and electronic equipment

Abstract

The invention provides an aluminum alloy surface treatment method, an aluminum alloy part and electronic equipment. The aluminum alloy surface treatment method comprises the steps that the aluminum alloy is subjected to anodic oxidation treatment to form an oxidation film, oxidation liquid in the anodic oxidation treatment comprises at least one of sulfuric acid, oxalic acid and citric acid, the content of Al < 3 + > in the oxidation liquid is 0.1 g / L to 8 g / L, the content of Cl <-> is smaller than or equal to 0.02 g / L, the content of NO3 <-> is smaller than or equal to 0.02 g / L, and the content of PO3 <-> is smaller than or equal to 0.02 g / L; the thickness of the oxide film is 5 [mu] m to 15 [mu] m.

Description

Technical Field

[0001] This application belongs to the field of electronic product technology, specifically relating to methods for surface treatment of aluminum alloys, aluminum alloy parts, and electronic devices. Background Technology

[0002] Aluminum alloys, with their low density, high strength, excellent thermal conductivity, and good machinability, are widely used in electronic devices. Related technologies involve anodizing aluminum alloys to create an oxide film, improving their surface finish. However, current improvements to anodizing processes primarily focus on enhancing the wear and corrosion resistance of the oxide film, with limited progress made in improving the adhesion of the oxide film. Therefore, improvements to the anodizing process are needed to enhance the adhesion of the oxide film. Summary of the Invention

[0003] In view of this, this application provides a method for surface treatment of aluminum alloys, aluminum alloy parts, and electronic devices.

[0004] In a first aspect, this application provides a method for surface treatment of aluminum alloys, comprising: anodizing the aluminum alloy to form an oxide film, wherein the oxidizing solution in the anodizing process includes at least one selected from sulfuric acid, oxalic acid, and citric acid, and the oxide film in the oxidizing solution contains Al 3+ The content ranges from 0.1 g / L to 8 g / L, Cl - The content of NO is less than or equal to 0.02 g / L. 3- The content is less than or equal to 0.02 g / L, PO 3- The content of the oxide is less than or equal to 0.02 g / L, and the thickness of the oxide film is 5 μm to 15 μm.

[0005] In a second aspect, this application provides an aluminum alloy part, which is manufactured by the method described in the first aspect. The aluminum alloy part includes an aluminum alloy substrate and an oxide film disposed on at least a portion of the surface of the aluminum alloy substrate, wherein the thickness of the oxide film is 5 μm to 15 μm.

[0006] Thirdly, this application provides an electronic device including a display screen, a back cover, and a mid-frame, wherein the back cover includes the aluminum alloy component described in the second aspect.

[0007] The aluminum alloy surface treatment method provided in this application uses an oxidizing solution including at least one of sulfuric acid, oxalic acid and citric acid, and controls the content of multiple ions in the oxidizing solution to form an oxide film of suitable thickness. This results in excellent bonding performance between the oxide film and the aluminum alloy after anodizing treatment, improving the adhesion of the oxide film to the aluminum alloy. This is beneficial for the use of the anodized aluminum alloy in electronic devices and extends its service life. Attached Figure Description

[0008] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the embodiments of this application will be described below.

[0009] Figure 1 A flowchart illustrating a method for surface treatment of aluminum alloys according to an embodiment of this application.

[0010] Figure 2 A flowchart of a method for surface treatment of aluminum alloys provided in another embodiment of this application.

[0011] Figure 3 A flowchart of a method for surface treatment of aluminum alloys provided in another embodiment of this application.

[0012] Figure 4 A schematic diagram of the structure of an electronic device provided in one embodiment of this application. Detailed Implementation

[0013] The following are exemplary embodiments of this application. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principles of this application, and these improvements and modifications are also considered to be within the scope of protection of this application.

[0014] The following disclosure provides many different implementations or examples for implementing the technical solutions of this application. To simplify the disclosure, specific example settings are described below. Of course, these are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various implementations and / or settings discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0015] This application provides a method for surface treatment of aluminum alloys, comprising: anodizing the aluminum alloy to form an oxide film, wherein the anodizing solution in the anodizing process includes at least one of sulfuric acid, oxalic acid, and citric acid, and the oxide film in the anodizing solution contains Al. 3+ The content ranges from 0.1 g / L to 8 g / L, Cl - The content of NO is less than or equal to 0.02 g / L. 3- The content is less than or equal to 0.02 g / L, PO 3- The content of the oxide is less than or equal to 0.02 g / L, and the thickness of the oxide film is 5 μm to 15 μm.

[0016] Current anodizing processes are mostly designed for specific types of aluminum alloys to form an oxide film on their surfaces. Improvements to these processes primarily focus on enhancing the wear resistance and corrosion resistance of the oxide film, with limited research on improving its adhesion and reliability. Furthermore, due to variations in the elemental composition of different aluminum alloys, the adhesion between the oxide film and the alloy varies even when using the same anodizing process. Research on anodizing processes applicable to multiple types of aluminum alloys and capable of producing oxide films with high adhesion and reliability is scarce. This application utilizes an oxidation solution containing at least one of sulfuric acid, oxalic acid, and citric acid, and controls the Al content in the oxidation solution... 3+ Cl - NO 3- PO 3- The content of [specific element] forms an oxide film of suitable thickness, thereby enabling the formation of an oxide film with good adhesion and high reliability on the surface of aluminum alloy, which is beneficial to the use of aluminum alloy after surface treatment.

[0017] The inventors of this application have discovered that Al in oxidizing solutions... 3+ Cl - NO 3- PO 3- The content of Al affects the bonding performance between the formed oxide film and the aluminum alloy; for example, the content of Al in the oxidation solution... 3+ Excessive Cl content will affect the acidity of the oxidation solution, the adhesion between the oxide film and the aluminum alloy, and the Cl content in the oxidation solution. - Excessive NO content can cause corrosion spots on the formed oxide film, affecting the adhesion between the oxide film and the aluminum alloy. 3- Excessive PO content can dissolve the oxide film, hindering its formation and bonding with the aluminum alloy. 3- Excessive Al content will be adsorbed by the oxide film, affecting the adhesion between the oxide film and the aluminum alloy. This application controls the Al content in the oxidation solution... 3+ The content is 0.1g / L-8g / L, Cl - The content of NO is less than or equal to 0.02 g / L. 3- The content is less than or equal to 0.02 g / L, PO 3- A content of less than or equal to 0.02 g / L is beneficial for improving the bonding performance and reliability between the oxide film produced by anodizing and the aluminum alloy, thus facilitating the use of the surface-treated aluminum alloy. However, the combined effect of these ions can also affect the oxide film and the aluminum alloy, leading to a porous oxide film and impacting the bonding performance between the oxide film and the aluminum alloy. Specifically, the Al content in the oxidation solution... 3+The concentration of Cl in the oxidizing solution can be, but is not limited to, 0.1 g / L, 0.5 g / L, 0.8 g / L, 1 g / L, 1.2 g / L, 1.3 g / L, 1.5 g / L, 1.8 g / L, 2 g / L, 2.1 g / L, 2.4 g / L, 2.5 g / L, 2.7 g / L, 3 g / L, 3.2 g / L, 3.3 g / L, 3.5 g / L, 3.8 g / L, 4 g / L, 4.2 g / L, 4.5 g / L, 4.7 g / L, 4.8 g / L, 5 g / L, 5.5 g / L, 6 g / L, 6.5 g / L, 7 g / L, 7.5 g / L, or 8 g / L, etc.; - The content of NO can be, but is not limited to, below 0.02 g / L, below 0.018 g / L, below 0.015 g / L, below 0.012 g / L, below 0.01 g / L, below 0.007 g / L, or below 0.005 g / L, etc.; NO in the oxidation solution 3- The content can be, but is not limited to, below 0.02 g / L, below 0.018 g / L, below 0.015 g / L, below 0.012 g / L, below 0.01 g / L, below 0.007 g / L, or below 0.005 g / L, etc.; PO in the oxidation solution 3- The content may be, but is not limited to, below 0.02g / L, below 0.018g / L, below 0.015g / L, below 0.012g / L, below 0.01g / L, below 0.007g / L, or below 0.005g / L.

[0018] This application achieves a highly adhesive oxide film by anodizing using an oxidizing solution comprising at least one of sulfuric acid, oxalic acid, and citric acid. Exemplarily, the oxidizing solution may comprise sulfuric acid at concentrations of 190 g / L to 210 g / L (e.g., 190 g / L, 195 g / L, 197 g / L, 200 g / L, 203 g / L, 205 g / L, or 210 g / L, etc.), or the oxidizing solution may comprise sulfuric acid at concentrations of 10 g / L to 60 g / L (e.g., 10 g / L, 20 g / L, 25 g / L, 30 g / L, 35 g / L, 40 g / L, 50 g / L, 55 g / L, or 60 g / L, etc.) and sulfuric acid at concentrations of 30 g / L to 60 g / L (e.g., 30 g / L...). Oxalic acid at concentrations of 35 g / L, 40 g / L, 45 g / L, 50 g / L, 55 g / L, or 60 g / L, etc., or oxidizing solutions may include sulfuric acid at concentrations of 0 g / L to 40 g / L (e.g., 0 g / L, 5 g / L, 10 g / L, 15 g / L, 20 g / L, 30 g / L, 35 g / L, or 40 g / L, etc.) and citric acid at concentrations of 40 g / L to 80 g / L (e.g., 40 g / L, 45 g / L, 50 g / L, 55 g / L, 60 g / L, 70 g / L, 85 g / L, or 90 g / L, etc.).

[0019] When sulfuric acid is used as the oxidizing solution, the solution may contain 190 g / L to 210 g / L of sulfuric acid. The anodic oxidation voltage is 12 V to 14 V, the oxidation time is 1200 s to 4200 s, and the oxidation temperature is 13 °C to 17 °C. This anodic oxidation process also controls the Al content in the oxidizing solution. 3+ Cl - NO 3- PO 3- The concentration of [specific concentration] can further improve the quality and thickness of the formed oxide film, further enhance the bonding performance between the oxide film and the aluminum alloy, thereby improving the overall structural reliability. This anodizing process is referred to as the first anodizing process. Specifically, the oxidizing solution may include, but is not limited to, sulfuric acid at concentrations of 190 g / L, 195 g / L, 197 g / L, 200 g / L, 203 g / L, 205 g / L, or 210 g / L. Specifically, the oxidation voltage for anodizing can be, but is not limited to, 12V, 13V, or 14V; the oxidation time for anodizing can be, but is not limited to, 1200s, 1500s, 1800s, 1900s, 2000s, 2100s, 2300s, 2500s, 2700s, 3000s, 3300s, 3500s, 3700s, 3900s, 4000s, or 4200s; and the oxidation temperature for anodizing can be, but is not limited to, 13℃, 14℃, 15℃, 16℃, or 17℃.

[0020] When sulfuric acid and oxalic acid are used as the oxidizing solution, the oxidizing solution may include 10 g / L to 60 g / L of sulfuric acid and 30 g / L to 60 g / L of oxalic acid. The anodic oxidation voltage is 18 V to 22 V, the oxidation time is 1200 s to 3600 s, and the oxidation temperature is 20 °C to 30 °C. This anodic oxidation process also controls the Al content in the oxidizing solution. 3+ Cl - NO 3- PO 3-The concentration of certain substances can further improve the quality and thickness of the formed oxide film, and further enhance the bonding performance between the oxide film and the aluminum alloy, thereby improving the overall structural reliability. Specifically, the oxidizing solution may include, but is not limited to, 10 g / L, 20 g / L, 25 g / L, 30 g / L, 35 g / L, 40 g / L, 50 g / L, 55 g / L, or 60 g / L of sulfuric acid, and 30 g / L, 35 g / L, 40 g / L, 45 g / L, 50 g / L, 55 g / L, or 60 g / L of oxalic acid. This anodizing treatment is referred to as the second anodizing treatment. Specifically, the oxidation voltage of the anodizing treatment can be, but is not limited to, 18V, 19V, 20V, 21V, or 22V; the oxidation time of the anodizing treatment can be, but is not limited to, 1200s, 1500s, 1800s, 1900s, 2000s, 2100s, 2300s, 2500s, 2700s, 3000s, 3300s, 3500s, or 3600s; and the oxidation temperature of the anodizing treatment can be, but is not limited to, 20℃, 21℃, 22℃, 23℃, 24℃, 25℃, 26℃, 27℃, 28℃, 29℃, or 30℃.

[0021] Understandably, the concentration of oxalic acid in the oxidation solution of the second anodizing treatment is greater than that of sulfuric acid. This ensures the acidity of the oxidation solution and reduces the reaction between sulfuric acid and the aluminum alloy, such as reducing the reaction between sulfuric acid and zinc in the aluminum alloy, thereby improving the adhesion of the generated oxide film. For example, the concentration ratio of oxalic acid to sulfuric acid in the oxidation solution of the second anodizing treatment can be from 1.2:1 to 2.5:1. This is beneficial for improving the adhesion of the oxide film while ensuring the speed of the anodizing process and improving preparation efficiency. Specifically, the concentration ratio of oxalic acid to sulfuric acid in the oxidation solution of the second anodizing treatment can be, but is not limited to, 1.2:1, 1.3:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 2:1, 2.25:1, 2.3:1, or 2.5:1, etc. Specifically, the oxidizing solution for the second anodizing treatment may include 10 g / L of sulfuric acid and 20 g / L of oxalic acid, or the oxidizing solution for the second anodizing treatment may include 20 g / L of sulfuric acid and 45 g / L of oxalic acid, or the oxidizing solution for the second anodizing treatment may include 40 g / L of sulfuric acid and 60 g / L of oxalic acid, etc.

[0022] When sulfuric acid and citric acid are used as the oxidizing solution, the oxidizing solution comprises 0 g / L to 40 g / L of sulfuric acid and 40 g / L to 80 g / L of citric acid. The anodic oxidation voltage is 14 V to 18 V, the oxidation time is 2000 s to 4200 s, and the oxidation temperature is 25 °C to 35 °C. This anodic oxidation process also controls the Al content in the oxidizing solution. 3+ Cl - NO3- PO 3- The concentration of [specific concentration] can further improve the quality and thickness of the formed oxide film, further enhance the bonding performance between the oxide film and the aluminum alloy, thereby improving the overall structural reliability. This anodizing process is referred to as the third anodizing process. Specifically, the oxidizing solution may include, but is not limited to, 0 g / L, 5 g / L, 10 g / L, 15 g / L, 20 g / L, 30 g / L, 35 g / L, or 40 g / L of sulfuric acid, and 40 g / L, 45 g / L, 50 g / L, 55 g / L, 60 g / L, 70 g / L, 85 g / L, or 90 g / L of citric acid. Specifically, the oxidation voltage of the anodizing treatment can be, but is not limited to, 14V, 15V, 16V, 17V, or 18V; the oxidation time of the anodizing treatment can be, but is not limited to, 2000s, 2400s, 2700s, 3000s, 3200s, 3500s, 3700s, 3800s, 4000s, 4100s, or 4200s; and the oxidation temperature of the anodizing treatment can be, but is not limited to, 25℃, 26℃, 27℃, 28℃, 29℃, 30℃, 31℃, 32℃, 33℃, 34℃, or 35℃.

[0023] Understandably, the concentration of citric acid in the oxidation solution of the third anodizing process is greater than that of sulfuric acid. This ensures the acidity of the oxidation solution and reduces the reaction between sulfuric acid and the aluminum alloy, such as reducing the reaction between sulfuric acid and zinc in the aluminum alloy, thereby improving the adhesion of the generated oxide film. For example, the concentration ratio of citric acid to sulfuric acid in the oxidation solution of the third anodizing process can be from 1.2:1 to 2.5:1. This is beneficial for improving the adhesion of the oxide film while ensuring the speed of the anodizing process and improving preparation efficiency. Specifically, the concentration ratio of citric acid to sulfuric acid in the oxidation solution of the third anodizing process can be, but is not limited to, 1.2:1, 1.3:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 2:1, 2.25:1, 2.3:1, or 2.5:1, etc. Specifically, the oxidizing solution for the third anodizing treatment may include 10 g / L of sulfuric acid and 25 g / L of citric acid, or the oxidizing solution for the third anodizing treatment may include 35 g / L of sulfuric acid and 42 g / L of citric acid, or the oxidizing solution for the third anodizing treatment may include 40 g / L of sulfuric acid and 60 g / L of citric acid.

[0024] In this application, at least one of the first anodizing treatment, the second anodizing treatment, and the third anodizing treatment can be used to perform surface treatment on aluminum alloys.

[0025] For example, an aluminum alloy can be placed in an electrolytic cell as the anode, and an oxide solution can be injected into the cell. The anode and cathode are connected to a power source for anodizing. Specifically, the cathode material can be, but is not limited to, platinum, copper, aluminum, stainless steel, etc. Before anodizing, a barrier layer can be applied to the surface of the aluminum alloy that does not require anodizing. After anodizing, the aluminum alloy can be washed with water to remove residual oxide solution from its surface; for example, ultrasonic washing can be performed.

[0026] In one embodiment of this application, the content of alloying elements in the aluminum alloy is 6 wt% to 10 wt%. A higher content of alloying elements in the aluminum alloy can affect the bonding performance of the oxide film produced after anodizing. However, the oxide film produced by the aluminum alloy surface treatment method provided in this application exhibits excellent bonding performance with the aluminum alloy containing a higher content of alloying elements, overcoming the influence of alloying elements on the bonding performance of the oxide film and thus benefiting the use of the aluminum alloy. Specifically, the content of alloying elements in the aluminum alloy can be, but is not limited to, 6 wt%, 6.2 wt%, 6.5 wt%, 6.7 wt%, 6.9 wt%, 7 wt%, 7.1 wt%, 7.4 wt%, 7.5 wt%, 7.8 wt%, 8 wt%, 8.3 wt%, 8.5 wt%, 8.8 wt%, 9 wt%, 9.2 wt%, 9.5 wt%, 9.8 wt%, or 10 wt%. Understandably, when the content of alloying elements in aluminum alloys is less than 6 wt%, the influence of alloying elements on the bonding performance of oxide films is relatively small. The aluminum alloy surface treatment method provided in this application is also applicable to aluminum alloys with an alloying element content of less than 6 wt%. It can not only reduce the influence of alloying element content on the adhesion performance of oxide films, but also improve the adhesion performance of oxide films through this surface treatment method, thereby obtaining an oxide film with excellent bonding performance and improving the reliability of the overall structure of aluminum alloys after anodizing.

[0027] In one embodiment of this application, the zinc content in the aluminum alloy is greater than or equal to 1 wt%. A high zinc content in the aluminum alloy can affect the bonding performance of the oxide film. However, the oxide film produced by the aluminum alloy surface treatment method provided in this application exhibits excellent bonding performance with aluminum alloys with a high zinc content, overcoming the negative impact of high zinc content on the oxide film bonding performance and thus benefiting the use of the aluminum alloy. Specifically, the zinc content in the aluminum alloy can be, but is not limited to, 1 wt% or more, 2 wt% or more, 3 wt% or more, 4 wt% or more, or 5 wt% or more. It is understood that when the zinc content in the aluminum alloy is less than 1 wt%, the impact of zinc on the bonding performance of the oxide film is relatively small. The aluminum alloy surface treatment method provided in this application is also applicable to aluminum alloys with a zinc content of less than 1 wt%, and can obtain an oxide film with excellent bonding performance.

[0028] For example, the aluminum alloy may include at least one of 7-series aluminum alloys and die-cast aluminum alloys. 7-series aluminum alloys and die-cast aluminum alloys have advantages such as high strength, wear resistance, scratch resistance, and corrosion resistance, which are beneficial for use in electronic devices and improve their performance. Compared to 6-series aluminum alloys, 7-series aluminum alloys and die-cast aluminum alloys have higher alloy element content and higher zinc content. Anodizing treatments suitable for 6-series aluminum alloys are not applicable to 7-series aluminum alloys and die-cast aluminum alloys. However, the aluminum alloy surface treatment method provided in this application is applicable not only to 6-series aluminum alloys but also to 7-series aluminum alloys and die-cast aluminum alloys, and can obtain an oxide film with excellent bonding performance. In one embodiment of this application, the chemical composition of the 7-series aluminum alloy includes 90 wt% to 94 wt% Al, 1 wt% to 2.5 wt% Mg, 0 wt% to 1 wt% Si, 0.1 wt% to 1 wt% Cu, 4.9 wt% to 8 wt% Zn, 0 wt% to 0.3 wt% Mn, 0 wt% to 0.1 wt% Ti, and 0 wt% to 0.1 wt% Fe, which is beneficial for improving the performance of the 7-series aluminum alloy. It is understood that the 7-series aluminum alloy may also include unavoidable impurity elements. In one embodiment of this application, the chemical composition of the die-cast aluminum alloy includes 90 wt% to 94 wt% Al, 0.5 wt% to 1.5 wt% Mg, 0.1 wt% to 1 wt% Si, 0.1 wt% to 1 wt% Cu, 1 wt% to 5 wt% Zn, 0.5 wt% to 1 wt% Mn, and 0.3 wt% to 0.6 wt% Fe, which is beneficial for improving the performance of the die-cast aluminum alloy. It is understood that the die-cast aluminum alloy may also include other or unavoidable impurity elements.

[0029] In this application, the oxide film thickness is 5 μm to 15 μm. An oxide film of suitable thickness is beneficial for further improving the adhesion between the oxide film and the aluminum alloy substrate, thereby enhancing the reliability of the aluminum alloy parts. Specifically, the oxide film thickness can be, but is not limited to, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, or 15 μm. In one embodiment of this application, the oxide film thickness can be 5 μm to 8 μm. In another embodiment of this application, the oxide film thickness can be 8 μm to 13 μm.

[0030] Understandably, pretreatment of aluminum alloys is necessary before anodizing. Pretreatment alters the surface roughness and cleanliness of the aluminum alloy, thus facilitating the anodizing process. Please refer to [link / reference]. Figure 1 The flowchart of a method for surface treatment of aluminum alloys provided in one embodiment of this application includes:

[0031] S101: Pretreatment of aluminum alloy.

[0032] S102: The pretreated aluminum alloy is anodized to form an oxide film. The anodizing solution includes at least one of sulfuric acid, oxalic acid, and citric acid. The oxide solution contains Al... 3+ The content ranges from 0.1 g / L to 8 g / L, Cl - The content of NO is less than or equal to 0.02 g / L. 3- The content is less than or equal to 0.02 g / L, PO 3- The content is less than or equal to 0.02 g / L, and the thickness of the oxide film is 5 μm to 15 μm.

[0033] The process of S102 is as described above and will not be repeated here.

[0034] In step S101, the pretreatment may include at least one of grinding, polishing, sandblasting, and cleaning. Grinding removes burrs from the aluminum alloy, making its surface smoother and edges more rounded, while improving the surface roughness. Specifically, grinding can be performed using sandpaper, such as 400#, 800#, or 1200# sandpaper. In one embodiment, the surface roughness of the aluminum alloy after grinding can be 0.3 μm to 0.5 μm. Polishing gives the aluminum alloy a high-gloss finish, which is beneficial for its use. Sandblasting improves the surface roughness of the aluminum alloy, thereby improving its appearance, and the sandblasted surface also facilitates the adhesion of the oxide film. Cleaning removes oil stains from the aluminum alloy surface, which is beneficial for the adhesion of the oxide film produced by anodizing. In one embodiment, cleaning includes degreasing and oil removal. For example, a degreasing solution can be used for degreasing. The concentration of the degreasing solution can be from 50 g / L to 60 g / L. Specifically, the concentration of the degreasing solution can be, but is not limited to, 50 g / L, 52 g / L, 53 g / L, 55 g / L, 58 g / L, 59 g / L, or 60 g / L. The degreasing solution can include, but is not limited to, at least one of trisodium phosphate, sodium carbonate, and sodium silicate. For example, the degreasing treatment time can be from 3 min to 10 min, and the degreasing treatment temperature can be from 50℃ to 70℃. Specifically, the degreasing treatment time can be, but is not limited to, 3 min, 4 min, 4.5 min, 5 min, 5.5 min, 6 min, 7 min, 8 min, 9 min, or 10 min, and the degreasing treatment temperature can be, but is not limited to, 50℃, 53℃, 55℃, 58℃, 60℃, 62℃, 65℃, 67℃, or 70℃. For example, an oil-removing solution can be used for oil removal. For example, the degreasing treatment time can be from 0.5 min to 5 min, and the degreasing treatment temperature can be from 40℃ to 60℃. Specifically, the degreasing treatment time can be, but is not limited to, 0.5 min, 1 min, 2 min, 3 min, 4 min, or 5 min, and the degreasing treatment temperature can be, but is not limited to, 40℃, 43℃, 45℃, 50℃, 55℃, 57℃, or 60℃. After the degreasing treatment, the aluminum alloy can also be washed with water to remove any residual degreasing solution or degreasing solution.

[0035] The anodized aluminum alloy comprises an aluminum alloy substrate and an oxide film disposed on the surface of the aluminum alloy substrate. The aluminum alloy treated by the above method exhibits excellent adhesion between the oxide film and the aluminum alloy substrate. For example, after treatment at a first temperature of 120°C or higher for 30 minutes, the oxide film on the anodized aluminum alloy does not peel off. Further, a first temperature of 150°C or higher indicates even higher oxide film adhesion. For example, after treatment in a vacuum at a second temperature of 40°C or higher for 30 minutes, the oxide film on the anodized aluminum alloy does not peel off. Further, a second temperature of 60°C or higher indicates even higher oxide film adhesion. The vacuum degree is 10... -2 Below Pa.

[0036] The oxide film produced after anodizing has a porous structure, meaning it has multiple openings. Understandably, anodized aluminum alloys can be colored to change the appearance of the oxide film and expand its application scenarios. Understandably, colored aluminum alloys can also undergo a sealing process, where a sealing agent fills and seals the openings of the porous structure of the oxide film. This sealing process encapsulates the colorant within the porous structure of the oxide film, ensuring the long-term reliability of the aluminum alloy's appearance color. Please refer to [link / reference]. Figure 2 The flowchart of a method for surface treatment of aluminum alloys provided in another embodiment of this application includes:

[0037] S201: Anodizing of aluminum alloys to form an oxide film. The anodizing solution includes at least one of sulfuric acid, oxalic acid, and citric acid. The oxide film in the anodizing solution contains Al... 3+ The content ranges from 0.1 g / L to 8 g / L, Cl - The content of NO is less than or equal to 0.02 g / L. 3- The content is less than or equal to 0.02 g / L, PO 3- The content is less than or equal to 0.02 g / L, and the thickness of the oxide film is 5 μm to 15 μm.

[0038] S202: Coloring and sealing treatment of anodized aluminum alloy.

[0039] The process of S201 is as described above and will not be repeated here.

[0040] In S202, the anodized aluminum alloy can be placed in a solution containing a colorant, allowing the colorant to fill the porous structure of the oxide film, thus achieving the coloring process. Due to the small pore size of the porous structure of the oxide film, the colorant can diffuse and fill the porous structure through capillary action. The type and color of the colorant in this application can be selected as needed; for example, organic colorants (such as organic water-soluble colorants, organic oil-based colorants, etc.) and inorganic colorants can be selected. After the coloring process, the aluminum alloy can be washed with water to remove any residual colorant from the surface. In the sealing process, any commercially available sealing agent can be selected. In one embodiment, the sealing agent can be colorless and transparent, so that it does not affect the appearance color of the aluminum alloy. The aluminum alloy after coloring and sealing includes an aluminum alloy substrate, an oxide film disposed on the surface of the aluminum alloy substrate, and a colorant and a sealing agent disposed in the porous structure of the oxide film. The coloring and sealing processes do not affect the bonding performance between the oxide film and the aluminum alloy substrate.

[0041] Please see Figure 3 The flowchart of a method for surface treatment of aluminum alloys provided in another embodiment of this application includes:

[0042] S301: Pretreatment of aluminum alloy.

[0043] S302: Anodizing is performed on pretreated aluminum alloys to form an oxide film. The anodizing solution includes at least one of sulfuric acid, oxalic acid, and citric acid. The oxide solution contains Al... 3+ The content ranges from 0.1 g / L to 8 g / L, Cl - The content of NO is less than or equal to 0.02 g / L. 3- The content is less than or equal to 0.02 g / L, PO 3- The content is less than or equal to 0.02 g / L, and the thickness of the oxide film is 5 μm to 15 μm.

[0044] S303: Coloring and sealing treatment of anodized aluminum alloy.

[0045] The processes for S301, S302, and S303 are as described above and will not be repeated here. The aluminum alloys treated with pretreatment, anodizing, coloring, and sealing exhibit excellent bonding properties with their improved appearance, which is beneficial for their use.

[0046] This application provides an aluminum alloy part, which is manufactured by the method described above. The aluminum alloy part includes an aluminum alloy substrate and an oxide film disposed on at least a portion of the surface of the aluminum alloy substrate, the oxide film having a thickness of 5 μm to 15 μm.

[0047] Understandably, since the oxide film has a porous structure, aluminum alloy parts can also include colorants disposed within this porous structure, thereby improving the appearance of the aluminum alloy parts and benefiting their use. Understandably, aluminum alloy parts can also include sealing agents disposed within the porous structure, used to enclose the colorants within the porous structure. Sealing agents play a role in sealing and protecting the colorants, improving the long-term reliability of the appearance of the colored aluminum alloy parts.

[0048] For example, after treating the aluminum alloy part at a first temperature of 120°C or higher for 30 minutes, the oxide film showed no peeling. Further, the first temperature was greater than or equal to 150°C, indicating even stronger oxide film adhesion. For example, after treating the aluminum alloy part in a vacuum at a second temperature of 40°C or higher for 30 minutes, the oxide film showed no peeling. Further, the second temperature was greater than or equal to 60°C, indicating even stronger oxide film adhesion. The vacuum level is 10... -2 The pressure is below 10 Pa. It can be seen that the oxide film on the aluminum alloy parts has excellent adhesion and high reliability, which is beneficial to the use of aluminum alloy parts.

[0049] The first test in the following embodiments involves placing the anodized aluminum alloy at a first temperature for 30 minutes, then removing it and cooling it in water below 25°C within 5 seconds. After removal, 3M 610 tape (or other tapes of equivalent viscosity) is adhered to the oxide film surface, statically pressed for more than 5 seconds, and then quickly pulled off. This process is repeated three times at the same location, and no oxide film is observed to have peeled off. The second test involves placing the anodized aluminum alloy in a vacuum furnace at a second temperature for 30 minutes, where the vacuum degree of the furnace is 9 × 10⁻⁶. -3After removing the oxide film, apply 3M 610 tape (or other tapes of equivalent viscosity) to the surface of the oxide film, apply static pressure for more than 5 seconds, and then quickly pull up the tape. Repeat this process three times at the same location, observing that the oxide film does not peel off. In the following embodiments, the element content of 6-series aluminum alloys, 7-series aluminum alloys, and die-cast aluminum alloys can be selected as needed. For example, the chemical composition of 6-series aluminum alloys may include 95wt% to 98wt% Al, 0.5wt% to 1.5wt% Mg, 0.5wt% to 1.3wt% Si, 0.4wt% to 1.6wt% Cu, 0wt% to 0.3wt% Mn, 0wt% to 0.1wt% Ti, 0wt% to 0.1wt% Zn, and 0wt% to 0.1wt% Fe. 6-series aluminum alloys may also contain unavoidable impurity elements. The chemical composition of 7-series aluminum alloys may include 90wt% to 94wt%... The chemical composition of die-cast aluminum alloys may include 90wt% to 94wt% Al, 0.5wt% to 1.5wt% Mg, 0.1wt% to 1wt% Si, 0.1wt% to 1wt% Cu, 1wt% to 5wt% Zn, 0.5wt% to 1wt% Mn and 0.3wt% to 0.6wt% Fe.

[0050] In one embodiment of this application, a 6-series aluminum alloy is subjected to anodizing treatment, wherein the anodizing solution is sulfuric acid with a concentration of 190 g / L to 210 g / L, and the anodizing solution contains Al. 3+ The content is 5g / L to 13g / L, the oxidation voltage of the anodizing treatment is 12V to 14V, the oxidation time is 45min to 70min, the oxidation temperature is 16℃ to 19℃, and the thickness of the resulting oxide film is 10μm to 15μm. The anodized 6-series aluminum alloy is subjected to a first test at a first temperature of 200℃ and a second test at a second temperature of 100℃. After the first and second tests, the oxide film on its surface does not peel off, indicating that the oxide film has good adhesion to the 6-series aluminum alloy substrate. In another embodiment of this application, 7-series aluminum alloy is subjected to the same anodizing treatment as described above, followed by a first test at a first temperature of 100℃ and a second test at a second temperature of 40℃. The oxide film on its surface peels off, indicating that this anodizing treatment is suitable for 6-series aluminum alloys but not for 7-series aluminum alloys, and the adhesion between the resulting oxide film and the 7-series aluminum alloy substrate is poor.

[0051] In one embodiment of this application, a 7-series aluminum alloy is subjected to anodizing treatment, wherein the anodizing solution is sulfuric acid with a concentration of 190 g / L to 210 g / L, and the anodizing solution contains Al. 3+ The content ranges from 0.1 g / L to 3 g / L, Cl - The content of NO is less than or equal to 0.02 g / L. 3- The content is less than or equal to 0.02 g / L, PO 3- The content of [aluminum oxide] is less than or equal to 0.02 g / L. The anodizing voltage is 12V to 14V, the oxidation time is greater than 70 min, the oxidation temperature is 13℃ to 17℃, and the thickness of the resulting oxide film is 16 μm to 20 μm. The anodized 7-series aluminum alloy was subjected to a first test at 120℃ and a second test at 40℃. After the first test, the oxide film on its surface peeled off; after the second test, the oxide film on its surface peeled off, indicating weak adhesion of the oxide film. It is understood that the oxide film obtained in any specific embodiment within the parameter range of the anodizing process provided in this embodiment peeled off after the above-mentioned first and second tests.

[0052] In one embodiment of this application, a 7-series aluminum alloy is subjected to anodizing treatment, wherein the anodizing solution is sulfuric acid with a concentration of 190 g / L to 210 g / L; the anodizing solution contains Al 3+ The content is greater than 8 g / L, and / or the Cl in the oxidation solution - The content of NO is greater than 0.02 g / L, and / or the NO content in the oxidation solution is higher than 0.02 g / L. 3- The content is greater than 0.02 g / L, and / or the PO content in the oxidation solution is greater than 0.02 g / L. 3- The content is greater than 0.02 g / L; the anodizing voltage is 12V to 14V, the oxidation time is 35 min to 70 min, the oxidation temperature is 13℃ to 17℃, and the thickness of the resulting oxide film is 10 μm to 15 μm. The anodized 7-series aluminum alloy was subjected to a first test at 120℃ and a second test at 40℃. After the first test, the oxide film on its surface peeled off; after the second test, the oxide film on its surface peeled off, indicating weak adhesion of the oxide film. It is understood that the oxide film obtained in any specific embodiment within the parameter range of the anodizing process provided in this embodiment peeled off after the above-mentioned first and second tests.

[0053] In one embodiment of this application, 7-series aluminum alloys are subjected to anodizing treatment, wherein the anodizing solution is sulfuric acid with a concentration greater than 210 g / L, and the anodizing solution contains Al 3+ The content ranges from 0.1 g / L to 3 g / L, Cl - The content of NO is less than or equal to 0.02 g / L. 3- The content is less than or equal to 0.02 g / L, PO 3-The content of [aluminum oxide] is less than or equal to 0.02 g / L. The oxidation voltage of the anodizing treatment is 12V to 14V, the oxidation time is 35 min to 70 min, the oxidation temperature is 13℃ to 17℃, and the thickness of the resulting oxide film is 10 μm to 15 μm. The anodized 7-series aluminum alloy was subjected to a first test at a first temperature of 120℃ and a second test at a second temperature of 40℃. After the first test, the oxide film on its surface did not peel off, and after the second test, the oxide film on its surface did not peel off. The anodized 7-series aluminum alloy was subjected to a first test at a first temperature of 150℃ and a second test at a second temperature of 60℃. After the first test, the oxide film on its surface peeled off, and after the second test, the oxide film on its surface peeled off, indicating that the adhesion of the formed oxide film was improved. It can be understood that the oxide film obtained in any specific embodiment within the parameter range of the anodizing process provided in this embodiment will have consistent results after undergoing the same first and second tests as described above.

[0054] In one embodiment of this application, 7-series aluminum alloys are subjected to anodizing treatment, wherein the anodizing solution is sulfuric acid with a concentration of less than 190 g / L, and the anodizing solution contains Al 3+ The content ranges from 0.1 g / L to 3 g / L, Cl - The content of NO is less than or equal to 0.02 g / L. 3- The content is less than or equal to 0.02 g / L, PO 3- The content of [aluminum oxide] is less than or equal to 0.02 g / L. The oxidation voltage of the anodizing treatment is 12V to 14V, the oxidation time is 35 min to 70 min, the oxidation temperature is 13℃ to 17℃, and the thickness of the resulting oxide film is 10 μm to 15 μm. The anodized 7-series aluminum alloy was subjected to a first test at a first temperature of 120℃ and a second test at a second temperature of 40℃. After the first test, the oxide film on its surface did not peel off, and after the second test, the oxide film on its surface did not peel off. The anodized 7-series aluminum alloy was subjected to a first test at a first temperature of 150℃ and a second test at a second temperature of 60℃. After the first test, the oxide film on its surface peeled off, and after the second test, the oxide film on its surface peeled off, indicating that the adhesion of the formed oxide film was improved. It can be understood that the oxide film obtained in any specific embodiment within the parameter range of the anodizing process provided in this embodiment will have consistent results after undergoing the same first and second tests as described above.

[0055] In one embodiment of this application, a 7-series aluminum alloy is subjected to anodizing treatment, wherein the anodizing solution is 30 g / L to 60 g / L of oxalic acid, or the anodizing solution is 30 g / L to 60 g / L of oxalic acid and 80 g / L of sulfuric acid; the anodizing solution contains Al 3+ The content ranges from 0.1 g / L to 8 g / L, Cl -The content of NO is less than or equal to 0.02 g / L. 3- The content is less than or equal to 0.02 g / L, PO 3- The content of [aluminum oxide] is less than or equal to 0.02 g / L. The oxidation voltage of the anodizing treatment is 18V to 22V, the oxidation time is 20 min to 60 min, the oxidation temperature is 20℃ to 30℃, and the thickness of the resulting oxide film is 5 μm to 15 μm. The anodized 7-series aluminum alloy was subjected to a first test at a first temperature of 120℃ and a second test at a second temperature of 40℃. After the first test, the oxide film on its surface did not peel off, and after the second test, the oxide film on its surface did not peel off. The anodized 7-series aluminum alloy was subjected to a first test at a first temperature of 150℃ and a second test at a second temperature of 60℃. After the first test, the oxide film on its surface peeled off, and after the second test, the oxide film on its surface peeled off, indicating that the adhesion of the formed oxide film was improved. It can be understood that the oxide film obtained in any specific embodiment within the parameter range of the anodizing process provided in this embodiment will have consistent results after undergoing the same first and second tests as described above.

[0056] In one embodiment of this application, a 7-series aluminum alloy is subjected to anodizing treatment, wherein the anodizing solution is 50 g / L sulfuric acid and 40 g / L to 80 g / L citric acid, and the Al in the anodizing solution... 3+ The content ranges from 0.1 g / L to 8 g / L, Cl - The content of NO is less than or equal to 0.02 g / L. 3- The content is less than or equal to 0.02 g / L, PO 3- The content of [aluminum oxide] is less than or equal to 0.02 g / L. The oxidation voltage of the anodizing treatment is 14V to 18V, the oxidation time is 40 min to 70 min, the oxidation temperature is 25℃ to 35℃, and the thickness of the resulting oxide film is 5 μm to 15 μm. The anodized 7-series aluminum alloy was subjected to a first test at a first temperature of 120℃ and a second test at a second temperature of 40℃. After the first test, the oxide film on its surface did not peel off, and after the second test, the oxide film on its surface did not peel off. The anodized 7-series aluminum alloy was subjected to a first test at a first temperature of 150℃ and a second test at a second temperature of 60℃. After the first test, the oxide film on its surface peeled off, and after the second test, the oxide film on its surface peeled off, indicating that the adhesion of the formed oxide film was improved. It can be understood that the oxide film obtained in any specific embodiment within the parameter range of the anodizing process provided in this embodiment will have consistent results after undergoing the same first and second tests as described above.

[0057] In one embodiment of this application, a die-cast aluminum alloy is subjected to anodizing treatment, wherein the anodizing solution is sulfuric acid with a concentration greater than 210 g / L, and the anodizing solution contains Al 3+The content ranges from 0.1 g / L to 8 g / L, Cl - The content of NO is less than or equal to 0.02 g / L. 3- The content is less than or equal to 0.02 g / L, PO 3- The content of [agent] is less than or equal to 0.02 g / L. The anodizing voltage is 12V to 14V, the oxidation time is 35 min to 70 min, the oxidation temperature is 13℃ to 17℃, and the thickness of the resulting oxide film is 10 μm to 15 μm. The anodized die-cast aluminum alloy was subjected to a first test at 120℃ and a second test at 40℃. After the first test, the oxide film on its surface did not peel off, and after the second test, the oxide film on its surface did not peel off. The anodized die-cast aluminum alloy was subjected to a first test at 150℃ and a second test at 60℃. After the first test, the oxide film on its surface peeled off, and after the second test, the oxide film on its surface peeled off, indicating that the adhesion of the formed oxide film has been improved. It is understood that the oxide film obtained in any specific embodiment within the parameter range of the anodizing process provided in this embodiment will have consistent results after undergoing the same first and second tests.

[0058] In one embodiment of this application, a 7-series aluminum alloy is subjected to anodizing treatment, wherein the anodizing solution is sulfuric acid with a concentration of 190 g / L to 210 g / L, and the anodizing solution contains Al. 3+ The content ranges from 0.1 g / L to 3 g / L, Cl - The content of NO is less than or equal to 0.02 g / L. 3- The content is less than or equal to 0.02 g / L, PO 3- The content of [aluminum oxide] is less than or equal to 0.02 g / L. The anodizing voltage is 12V to 14V, the oxidation time is 35 min to 70 min, the oxidation temperature is 13℃ to 17℃, and the thickness of the resulting oxide film is 10 μm to 15 μm. The anodized 7-series aluminum alloy was subjected to a first test at 180℃ and a second test at 80℃. After the first test, the oxide film on the surface did not peel off; after the second test, the oxide film on the surface did not peel off, indicating excellent oxide film adhesion. It is understood that the oxide film obtained in any specific embodiment within the parameter range of the anodizing process provided in this embodiment did not peel off after the above first and second tests.

[0059] In one embodiment of this application, a 7-series aluminum alloy is subjected to anodizing treatment, wherein the anodizing solution is sulfuric acid with a concentration of 190 g / L to 210 g / L, and the anodizing solution contains Al. 3+ The content ranges from 3 g / L to 8 g / L, Cl - The content of NO is less than or equal to 0.02 g / L. 3-The content is less than or equal to 0.02 g / L, PO 3- The content of [aluminum oxide] is less than or equal to 0.02 g / L. The anodizing voltage is 12V to 14V, the oxidation time is 35 min to 70 min, the oxidation temperature is 13℃ to 17℃, and the thickness of the resulting oxide film is 10 μm to 15 μm. The anodized 7-series aluminum alloy was subjected to a first test at 150℃ and a second test at 60℃. After the first test, the oxide film on the surface did not peel off; after the second test, the oxide film on the surface did not peel off, indicating excellent oxide film adhesion. It is understood that the oxide film obtained in any specific embodiment within the parameter range of the anodizing process provided in this embodiment did not peel off after the above-mentioned first and second tests.

[0060] In one embodiment of this application, a 7-series aluminum alloy is subjected to anodizing treatment, wherein the anodizing solution is sulfuric acid with a concentration of 190 g / L to 210 g / L, and the anodizing solution contains Al. 3+ The content is 5g / L to 8g / L, Cl - The content of NO is less than or equal to 0.02 g / L. 3- The content is less than or equal to 0.02 g / L, PO 3- The content of [aluminum oxide] is less than or equal to 0.02 g / L. The anodizing voltage is 12V to 14V, the oxidation time is 35 min to 70 min, the oxidation temperature is 13℃ to 17℃, and the thickness of the resulting oxide film is 10 μm to 15 μm. The anodized 7-series aluminum alloy was subjected to a first test at 150℃ and a second test at 60℃. After the first test, the oxide film on the surface did not peel off; after the second test, the oxide film on the surface did not peel off, indicating excellent oxide film adhesion. It is understood that the oxide film obtained in any specific embodiment within the parameter range of the anodizing process provided in this embodiment did not peel off after the above-mentioned first and second tests.

[0061] In one embodiment of this application, a 7-series aluminum alloy is subjected to anodizing treatment, wherein the anodizing solution is sulfuric acid with a concentration of 190 g / L to 210 g / L, and the anodizing solution contains Al. 3+ The content is 5g / L to 8g / L, Cl - The content of NO is less than or equal to 0.02 g / L. 3- The content is less than or equal to 0.02 g / L, PO 3-The content of [aluminum oxide] is less than or equal to 0.02 g / L. The anodizing voltage is 12V to 14V, the oxidation time is 20 min to 35 min, the oxidation temperature is 13℃ to 17℃, and the thickness of the resulting oxide film is 5 μm to 10 μm. The anodized 7-series aluminum alloy was subjected to a first test at a temperature of 200℃ and a second test at a temperature of 100℃. After the first test, the oxide film on the surface did not peel off, and after the second test, the oxide film on the surface did not peel off, indicating excellent oxide film adhesion. It is understood that the oxide film obtained in any specific embodiment within the parameter range of the anodizing process provided in this embodiment did not peel off after the above-mentioned first and second tests.

[0062] In one embodiment of this application, a die-cast aluminum alloy is subjected to anodizing treatment, wherein the anodizing solution is sulfuric acid with a concentration of 190 g / L to 210 g / L, and the anodizing solution contains Al. 3+ The content ranges from 0.1 g / L to 3 g / L, Cl - The content of NO is less than or equal to 0.02 g / L. 3- The content is less than or equal to 0.02 g / L, PO 3- The content of [agent] is less than or equal to 0.02 g / L. The anodizing voltage is 12V to 14V, the oxidation time is 35 min to 70 min, the oxidation temperature is 13℃ to 17℃, and the thickness of the resulting oxide film is 10 μm to 15 μm. The anodized die-cast aluminum alloy was subjected to a first test at 180℃ and a second test at 80℃. After the first test, the oxide film on its surface did not peel off; after the second test, the oxide film on its surface did not peel off, indicating excellent oxide film adhesion. It is understood that the oxide film obtained in any specific embodiment within the parameter range of the anodizing process provided in this embodiment did not peel off after the above first and second tests.

[0063] In one embodiment of this application, a 7-series aluminum alloy is subjected to anodizing treatment, wherein the anodizing solution is composed of 10 g / L to 60 g / L sulfuric acid and 30 g / L to 60 g / L oxalic acid, and the anodizing solution contains Al 3+ The content ranges from 0.1 g / L to 8 g / L, Cl - The content of NO is less than or equal to 0.02 g / L. 3- The content is less than or equal to 0.02 g / L, PO 3-The content of [aluminum oxide] is less than or equal to 0.02 g / L. The anodizing voltage is 18V to 22V, the oxidation time is 20 min to 60 min, the oxidation temperature is 20℃ to 30℃, and the thickness of the resulting oxide film is 5 μm to 15 μm. The anodized 7-series aluminum alloy was subjected to a first test at a temperature of 200℃ and a second test at a temperature of 100℃. After the first test, the oxide film on the surface did not peel off; after the second test, the oxide film on the surface did not peel off, indicating excellent oxide film adhesion. It is understood that the oxide film obtained in any specific embodiment within the parameter range of the anodizing process provided in this embodiment did not peel off after the above-mentioned first and second tests.

[0064] In one embodiment of this application, a 7-series aluminum alloy is subjected to anodizing treatment, wherein the anodizing solution is sulfuric acid of 0 g / L to 40 g / L and citric acid of 40 g / L to 80 g / L, and the Al content in the anodizing solution is... 3+ The content ranges from 0.1 g / L to 8 g / L, Cl - The content of NO is less than or equal to 0.02 g / L. 3- The content is less than or equal to 0.02 g / L, PO 3- The content of [aluminum oxide] is less than or equal to 0.02 g / L. The anodizing voltage is 14V to 18V, the oxidation time is 40 min to 70 min, the oxidation temperature is 25℃ to 35℃, and the thickness of the resulting oxide film is 5 μm to 15 μm. The anodized 7-series aluminum alloy was subjected to a first test at a temperature of 200℃ and a second test at a temperature of 100℃. After the first test, the oxide film on the surface did not peel off, and after the second test, the oxide film on the surface did not peel off, indicating excellent oxide film adhesion. It is understood that the oxide film obtained in any specific embodiment within the parameter range of the anodizing process provided in this embodiment did not peel off after the above-mentioned first and second tests.

[0065] As can be seen from the above, this application improves the bonding performance of the oxide film by using an oxidation solution containing at least one of sulfuric acid, oxalic acid, and citric acid, and by controlling the content of various ions in the oxidation solution and the thickness of the oxide film. Furthermore, by using at least one of the first anodizing treatment, the second anodizing treatment, and the third anodizing treatment to treat the aluminum alloy surface, the adhesion ability of the oxide film can be further improved. For example, the bonding performance of the oxide film on the surface of 7-series aluminum alloy can be close to or reach the bonding performance of the oxide film on the surface of 6-series aluminum alloy. At the same time, the aluminum alloy surface treatment method provided by this application is applicable to a variety of aluminum alloys, such as 7-series aluminum alloys and die-cast aluminum alloys. Of course, this aluminum alloy surface treatment method is also applicable to 6-series aluminum alloys, and an oxide film with good bonding performance can still be obtained, which is beneficial to the use of aluminum alloys.

[0066] This application also provides an electronic device including the aforementioned aluminum alloy component, which can improve the strength and reliability of the electronic device, thereby enhancing its performance and lifespan, and increasing product competitiveness. It is understood that the electronic device may include, but is not limited to, mobile phones, tablets, laptops, watches, MP3 players, MP4 players, GPS navigators, digital cameras, drones, vehicles, etc., and the aluminum alloy component may include, but is not limited to, the electronic device's housing (such as a back cover), frame, buttons, hinges, gears, support components, protective components, etc. Please refer to [link to relevant documentation]. Figure 4 This is a schematic diagram of the structure of an electronic device provided in one embodiment of this application. The electronic device 400 includes a display screen 401, a back cover 402, and a middle frame 403. The back cover 402 includes the aforementioned aluminum alloy parts, which can improve the performance and service life of the electronic device.

[0067] The above provides a detailed description of the embodiments provided in this application. This document elucidates and explains the principles and implementation methods of this application. The above description is only intended to help understand the methods and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for surface treatment of aluminum alloys, characterized in that, include: Anodizing is performed on aluminum alloys to form an oxide film. The anodizing solution includes at least one of sulfuric acid, oxalic acid, and citric acid. The oxide film in the anodizing solution contains Al. 3+ The content ranges from 0.1 g / L to 8 g / L, Cl - The content of NO is less than or equal to 0.02 g / L. 3- The content is less than or equal to 0.02 g / L, PO 3- The content of the oxide is less than or equal to 0.02 g / L, and the thickness of the oxide film is 5 μm to 15 μm.

2. The method as described in claim 1, characterized in that, The aluminum alloy contains 6 wt% to 10 wt% of alloying elements, and / or the aluminum alloy contains more than or equal to 1 wt% of zinc.

3. The method as described in claim 1 or 2, characterized in that, The oxidizing solution comprises sulfuric acid at a concentration of 190 g / L to 210 g / L, the anodic oxidation treatment has an oxidation voltage of 12 V to 14 V, an oxidation time of 1200 s to 4200 s, and an oxidation temperature of 13 °C to 17 °C.

4. The method as described in claim 1 or 2, characterized in that, The oxidizing solution comprises 10 g / L to 60 g / L of sulfuric acid and 30 g / L to 60 g / L of oxalic acid. The anodic oxidation treatment has an oxidation voltage of 18 V to 22 V, an oxidation time of 1200 s to 3600 s, and an oxidation temperature of 20 °C to 30 °C.

5. The method as described in claim 1 or 2, characterized in that, The oxidizing solution comprises 0 g / L to 40 g / L of sulfuric acid and 40 g / L to 80 g / L of citric acid. The anodic oxidation treatment has an oxidation voltage of 14 V to 18 V, an oxidation time of 2400 s to 4200 s, and an oxidation temperature of 25 °C to 35 °C.

6. The method as described in claim 1 or 2, characterized in that, The aluminum alloy includes 7-series aluminum alloys, the chemical composition of which includes 90 wt% to 94 wt% Al, 1 wt% to 2.5 wt% Mg, 0 wt% to 1 wt% Si, 0.1 wt% to 1 wt% Cu, 4.9 wt% to 8 wt% Zn, 0 wt% to 0.3 wt% Mn, 0 wt% to 0.1 wt% Ti and 0 wt% to 0.1 wt% Fe.

7. The method as described in claim 1 or 2, characterized in that, The aluminum alloy includes a die-cast aluminum alloy, the chemical composition of which includes 90 wt% to 94 wt% Al, 0.5 wt% to 1.5 wt% Mg, 0.1 wt% to 1 wt% Si, 0.1 wt% to 1 wt% Cu, 1 wt% to 5 wt% Zn, 0.5 wt% to 1 wt% Mn and 0.3 wt% to 0.6 wt% Fe.

8. The method as described in claim 1, characterized in that, Before the anodizing process, the aluminum alloy is pretreated, and / or After the aluminum alloy undergoes the anodizing treatment, it is then subjected to coloring and sealing treatment.

9. An aluminum alloy part, characterized in that, The aluminum alloy part is manufactured by the method according to any one of claims 1 to 8, the aluminum alloy part comprising an aluminum alloy substrate and an oxide film disposed on at least a portion of the surface of the aluminum alloy substrate, the oxide film having a thickness of 5 μm to 15 μm.

10. The aluminum alloy part as described in claim 9, characterized in that, The oxide film on the aluminum alloy part does not peel off after being treated at a first temperature for 30 minutes, and / or the oxide film on the aluminum alloy part does not peel off after being treated at a vacuum and a second temperature for 30 minutes, wherein the first temperature is greater than or equal to 120°C and the second temperature is greater than or equal to 40°C.

11. An electronic device, characterized in that, It includes a display screen, a back cover, and a mid-frame, wherein the back cover includes an aluminum alloy component as described in any one of claims 9 to 10.

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