Composite oxidation method suitable for aluminum-based material and mobile phone frame

Abstract

The invention discloses a composite oxidation method suitable for an aluminum-based material and a mobile phone frame, and relates to the technical field of strengthening treatment. The composite oxidation method comprises the step of manufacturing a strengthened film on the surface of a workpiece and comprises the following steps: connecting a positive electrode of a source power supply with a vacuum furnace and grounding, connecting a negative electrode of the source power supply with a source target, and enabling the waveform of the source power supply to be positive pulse, the voltage to be 400V-500V and the frequency to be 5KHz-15KHz; the vacuum furnace is vacuumized, and the temperature in the furnace is 70-80 DEG C; the negative electrode of an oxidation power supply is connected with the cathode plate, the positive electrode of the oxidation power supply is connected with the workpiece, the waveform of the oxidation power supply is that a plurality of negative pulses are input after 10 positive pulses are input, the voltage is 600V-700V, and the frequency is 5KHz-15KHz; and enabling the source power supply and the oxidation power supply to be in a turn-on state, and inputting oxygen into the vacuum furnace. The reinforced film prepared by the invention can reduce the possibility of bubbling and delaminating.

Description

Technical Field

[0001] The present application relates to the technical field of strengthening treatment, and in particular to a composite oxidation method suitable for aluminum-based materials and a mobile phone frame. Background Art

[0002] In order to reduce the weight of mobile phones, improve production efficiency and reduce costs, mobile phone parts such as mobile phone frames are made of aluminum using die casting. However, since aluminum is soft and has poor rust resistance, it must be surface-strengthened.

[0003] However, in the existing aluminum surface strengthening method, the bonding strength between the obtained strengthening film layer and the parts is poor, and blistering and delamination problems are prone to occur. Summary of the invention

[0004] The present application provides a composite oxidation method applicable to aluminum-based materials and a mobile phone frame to reduce the possibility of blistering and delamination of a strengthening film.

[0005] The present application provides a composite oxidation method applicable to aluminum-based materials, comprising making a strengthening film on the surface of a workpiece, wherein the workpiece is an aluminum-based material, and the making of the strengthening film on the surface of the workpiece comprises:

[0006] Connect the positive electrode of the source power supply to the vacuum furnace and to the ground, connect the negative electrode of the source power supply to the source target in the vacuum furnace, the waveform of the source power supply is a positive pulse, adjust the voltage of the source power supply to 400V to 500V, and adjust the frequency of the source power supply to 5KHz to 15KHz;

[0007] The vacuum furnace is evacuated, and the temperature inside the vacuum furnace is maintained at 70° C. to 80° C.;

[0008] Connect the negative electrode of the oxidation power source to the cathode plate in the vacuum furnace, the cathode plate is an aluminum-based material, connect the positive electrode of the oxidation power source to the workpiece, the distance between the cathode plate and the workpiece is greater than or equal to 50 mm, adjust the waveform of the oxidation power source to input a number of negative pulses after every 10 positive pulses, adjust the voltage of the oxidation power source to 600V to 700V, and adjust the frequency of the oxidation power source to 5KHz to 15KHz;

[0009] The source power supply and the oxidation power supply are turned on, and oxygen is introduced into the vacuum furnace for 40 to 50 minutes.

[0010] In some possible implementations, during the process of forming the strengthening film on the surface of the workpiece, the vacuum furnace is evacuated to 0.05 Pa to 0.1 Pa.

[0011] In some possible implementations, the distance between the cathode plate and the workpiece is set to 50 mm to 70 mm.

[0012] In some possible implementations, during the process of forming the strengthening film on the surface of the workpiece, the waveform of the oxidation power supply is 1 to 2 negative pulses after every 10 positive pulses.

[0013] In some possible implementations, before forming the strengthening film on the workpiece surface, the composite oxidation method applicable to aluminum-based materials further includes cleaning the workpiece surface and the cathode plate surface, and the cleaning of the workpiece surface and the cathode plate surface includes:

[0014] Connecting the positive electrode of the source power supply to the vacuum furnace and to the ground, and connecting the negative electrode of the source power supply to the source target in the vacuum furnace;

[0015] The cathode plate is connected in series with the workpiece and connected to the negative electrode of the oxidation power source, and the positive electrode of the oxidation power source is connected to the vacuum furnace and grounded;

[0016] Starting the source power supply, the waveform of the source power supply is a positive pulse, adjusting the voltage of the source power supply to 400V to 500V, adjusting the frequency of the source power supply to 5KHz to 15KHz, and evacuating the vacuum furnace;

[0017] When the temperature of the vacuum furnace reaches 70°C to 80°C and the vacuum degree reaches 1Pa to 10Pa, argon gas is injected into the vacuum furnace and the oxidation power supply is started. The oxidation power supply waveform is a positive pulse, the voltage of the oxidation power supply is 500V to 600V, and the frequency of the oxidation power supply is 5KHz to 15KHz. The workpiece and the cathode plate are bombarded with argon gas for 10 minutes to 15 minutes.

[0018] In some possible implementations, the source target is tubular.

[0019] In some possible implementations, the source target is made of titanium alloy material.

[0020] In addition, the present application also provides a mobile phone frame, including a frame body and a strengthening film, wherein the strengthening film is produced by the composite oxidation method applicable to aluminum-based materials provided in the above embodiments.

[0021] In some possible implementations, the strengthening film includes an aluminum oxide ceramic layer.

[0022] In some possible implementations, the thickness of the strengthening film is 5 μm to 8 μm.

[0023] Beneficial effects of the present application: The present application utilizes a process combining anodization and ion sputtering to produce a thicker strengthening film (i.e., an aluminum oxide ceramic film) on the surface of a workpiece, thereby enabling the strengthening film to have stronger wear resistance, corrosion resistance, and hardness, etc. At the same time, a layer of the strengthening film close to the surface of the workpiece can be combined with the aluminum in the workpiece to form a part of the workpiece, thereby enabling the strengthening film to have a stronger bonding performance with the workpiece, and reducing the risk of blistering and delamination of the strengthening film. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 A schematic flow diagram of a composite oxidation method in some embodiments is shown;

[0026] Figure 2 A schematic diagram of the process of step S100 in some embodiments is shown;

[0027] Figure 3 A schematic flow chart of step S200 in some embodiments is shown. DETAILED DESCRIPTION

[0028] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0029] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0030] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0031] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0032] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0033] like Figure 1 As shown, the embodiment provides a composite oxidation method applicable to aluminum-based materials (hereinafter referred to as the composite oxidation method), which can be used to prepare a thick and wear-resistant strengthening film on the surface of an aluminum-based workpiece to improve the structural performance of the workpiece. Among them, the composite oxidation method applicable to aluminum-based materials can be completed by a surface strengthening device (i.e., a vacuum coating device).

[0034] In some embodiments, the surface strengthening device may include a vacuum furnace, an oxidation power supply and a source power supply. In addition, a cathode plate, a source target and a workpiece rack are arranged in the vacuum furnace, and the workpiece to be strengthened can be placed on the workpiece rack.

[0035] In some embodiments, the source target may be tubular, and the source target may be made of a titanium alloy material.

[0036] like Figure 1 As shown, in some embodiments, the composite oxidation method may include:

[0037] S100, cleaning the workpiece surface and the cathode plate surface.

[0038] Combined with Figure 2 In some embodiments, step S100 may include:

[0039] S110, connecting the positive electrode of the source power supply to the vacuum furnace and to the ground, and connecting the negative electrode of the source power supply to the source target in the vacuum furnace.

[0040] Among them, the source power supply can be used for heating and heat preservation of the vacuum furnace during use, and the source power supply can cooperate with the oxidation power supply to clean the positive and negative electrodes of the oxidation power supply and the surface of the workpiece to prepare for the subsequent production of the strengthening film.

[0041] S120, connecting the cathode plate and the workpiece in series and connecting them to the negative electrode of the oxidation power supply, and the positive electrode of the oxidation power supply is connected to the vacuum furnace and grounded.

[0042] In the embodiment, both the cathode plate and the workpiece may be made of aluminum-based materials.

[0043] In some embodiments, the operation order of step S110 and step S120 may not be specifically limited. For example, step S110 may be performed before step S120, or step S110 may be performed after step S120.

[0044] S130, start the source power supply, the waveform of the source power supply is a positive pulse, adjust the voltage of the source power supply to 400V to 500V, adjust the frequency of the source power supply to 5KHz to 15KHz, and evacuate the vacuum furnace.

[0045] In the embodiment, after the source power supply is started, the source power supply can heat the vacuum furnace to gradually increase the temperature in the vacuum furnace. In addition, the vacuum furnace can be evacuated to make the vacuum furnace in a vacuum environment. For example, the vacuum furnace can be connected to a vacuum pump, and the vacuum furnace can be evacuated by the vacuum pump.

[0046] S140, when the temperature of the vacuum furnace reaches 70℃ to 80℃ and the vacuum degree reaches 1Pa-10Pa, argon gas is injected into the vacuum furnace and the oxidation power supply is started. The oxidation power supply waveform is a positive pulse, the voltage of the oxidation power supply is 500V to 600V, and the frequency of the oxidation power supply is 5KHz to 15KHz. Use argon gas to bombard the workpiece and the cathode plate for 10 minutes to 15 minutes.

[0047] Thus, dirt and oxide film on the surface of the workpiece and the cathode plate can be removed to prepare for the subsequent production of the strengthening film, improve the bonding strength between the strengthening film and the workpiece, and reduce the probability of bubbles and delamination in the strengthening film. In this process, the oxidation power supply can cooperate with the source power supply to clean the surface of the cathode plate and the workpiece.

[0048] S200, making a strengthening film on the surface of the workpiece.

[0049] Combined with Figure 3 In some embodiments, a strengthening film 200 may be formed on the surface of the cleaned workpiece. In some embodiments, step S200 may include:

[0050] S210, connect the positive electrode of the source power supply to the vacuum furnace and to the ground, connect the negative electrode of the source power supply to the source target in the vacuum furnace, the waveform of the source power supply is a positive pulse, adjust the voltage of the source power supply to 400V to 500V, and adjust the frequency of the source power supply to 5KHz to 15KHz.

[0051] In an embodiment, the operating parameters of the source power supply in step S200 may be consistent with the operating parameters of the source power supply in step S100.

[0052] S220, evacuate the vacuum furnace and maintain the temperature inside the vacuum furnace at 70°C to 80°C.

[0053] In the embodiment, the vacuum furnace may continue to be evacuated, and the vacuum degree of the vacuum furnace may be adjusted to 0.05 Pa to 0.1 Pa. In addition, based on step S100, the temperature inside the vacuum furnace may be maintained at 70° C. to 80° C.

[0054] S230, connect the negative electrode of the oxidation power supply to the cathode plate in the vacuum furnace, the cathode plate is an aluminum-based material, connect the positive electrode of the oxidation power supply to the workpiece, the distance between the cathode plate and the workpiece is greater than or equal to 50mm, adjust the waveform of the oxidation power supply to input several negative pulses after every 10 positive pulses, adjust the voltage of the oxidation power supply to 600V to 700V, and adjust the frequency of the oxidation power supply to 5KHz to 15KHz.

[0055] S240, the source power supply and the oxidation power supply are turned on, and oxygen is introduced into the vacuum furnace for 40 to 50 minutes.

[0056] In the embodiment, the source power supply can be kept turned on after entering step S200 based on step S100.

[0057] In some embodiments, during the preparation of the strengthening film, two reactions of anodic oxidation and ion sputtering may be included that are carried out simultaneously. Specifically, under the action of the superimposed electric field of the oxidation power supply and the source power supply, the oxygen in the vacuum furnace will be ionized, and the generated oxygen ions will move toward the workpiece (the workpiece is positively charged and is the anode) under the action of the electric field. After the oxygen ions reach the surface of the workpiece, they will react with the aluminum on the surface of the workpiece to generate aluminum oxide, that is, an anodic oxidation reaction occurs on the surface of the workpiece. In addition, the cathode plate may undergo ion sputtering under the action of the electric field of the oxidation power supply, and the sputtered aluminum ions may combine with the oxygen ions in the vacuum furnace to form uncharged aluminum oxide, and the aluminum oxide may be deposited on the workpiece under the action of inertia, that is, aluminum oxide is sputtered on the workpiece by an ion sputtering process. Thus, a dense aluminum oxide ceramic film, i.e., a strengthening film, can be formed on the surface of the workpiece. In some embodiments, the thickness of the strengthening film may be 5μm to 8μm.

[0058] In the related art, only a single anodic oxidation reaction is used to prepare the aluminum oxide strengthening film. When a layer of aluminum oxide is formed on the surface of the workpiece, it will prevent oxygen ions from reacting with the aluminum on the workpiece, thereby preventing aluminum oxide from continuing to form on the surface of the workpiece. That is, in the related art, only a thin aluminum oxide strengthening film can be prepared on the surface of the workpiece, and its wear resistance is poor.

[0059] In the present application, the anodization of the workpiece is combined with ion sputtering, which can effectively increase the formation speed of aluminum oxide and form a thicker (5μm to 8μm) strengthening film on the workpiece surface. In the conventional technology, only an aluminum oxide strengthening film with a thickness of less than 2 microns can be obtained on the workpiece surface.

[0060] In the present application, the distance between the cathode plate and the workpiece is set to be greater than or equal to 50 mm, so that the aluminum ions sputtered from the cathode plate have sufficient movement distance to combine with the oxygen ions and generate aluminum oxide. The inventors of the present application found that when the distance between the cathode plate and the workpiece is less than 50 mm, the aluminum ions sputtered from the cathode plate do not have time to combine with the oxygen ions, and the aluminum ions are positively charged and will repel the workpiece (anode), thereby failing to reach the surface of the workpiece.

[0061] In some embodiments, the distance between the cathode plate and the workpiece is greater than or equal to 50 mm, and the distance between the cathode plate and the workpiece is less than or equal to 70 mm. While ensuring that the aluminum ions sputtered from the cathode plate have sufficient moving distance to react with oxygen ions to generate aluminum oxide, it can ensure that the generated aluminum oxide can smoothly reach the surface of the workpiece under the action of inertia to be deposited on the workpiece. The inventors of the present application found that the aluminum ions sputtered from the cathode plate combine with oxygen ions to generate aluminum oxide. Since aluminum oxide is not charged and needs to rely on inertia to move, when the distance between the cathode plate and the workpiece is greater than 70 mm, only part of the generated aluminum oxide can reach the surface of the workpiece, affecting the sputtering speed, that is, affecting the generation speed of the strengthening film. In the embodiment of the present application, the distance between the cathode plate and the workpiece is set to 50 mm to 70 mm, which can ensure that aluminum oxide is deposited on the surface of the workpiece, so as to obtain thicker aluminum oxide on the surface of the workpiece, and improve the generation efficiency of the strengthening film. For example, in some embodiments, the distance between the cathode plate and the workpiece can be set to 50 mm, 55 mm, 60 mm, 62 mm, 65 mm, 68 mm, 70 mm, or any other value between 50 mm and 70 mm.

[0062] In addition, in the present application, the waveform of the oxidation power supply is adjusted to a composite waveform, that is, a number of negative pulses are input after every 10 positive pulses are input. Thus, during the sputtering process, the electrons gathered on the surface of the cathode plate can be neutralized to prevent the electrons from hindering the further sputtering of the cathode plate, ensuring that the cathode plate can be continuously sputtered, that is, ensuring the continuous generation of aluminum oxide. In some embodiments, the waveform of the oxidation power supply can be set to input 1 to 2 negative pulses after every 10 positive pulses are input.

[0063] In the embodiment of the present application, a 5 μm to 8 μm strengthening film can be obtained on the surface of the workpiece by combining anodizing and ion sputtering, that is, a thicker aluminum oxide ceramic film can be formed on the surface of the workpiece, and it can have higher hardness and corrosion resistance. At the same time, the hardness of the aluminum oxide ceramic film can be above HV1000, and it can have higher wear resistance. In addition, the aluminum oxide ceramic film obtained by combining anodizing and ion sputtering has better density and uniformity, can be polished, and can be thrown to a mirror effect.

[0064] In addition, in the present application, the side of the strengthening film close to the workpiece is formed by the combination of oxygen ions and aluminum on the surface of the workpiece, and can become a part of the workpiece, so that the strengthening film and the workpiece have a stronger bonding ability. In addition, the aluminum oxide deposited by ion sputtering and the aluminum oxide formed by the anodic oxidation reaction are the same material and can be integrated. As a result, the strengthening film as a whole can have a stronger bonding ability with the workpiece, reducing the probability of blistering, delamination and other problems in the strengthening film.

[0065] At present, the requirements for strengthening of mobile phone frames made of aluminum-based materials are as follows: (1) The deformation of the mobile phone frame after strengthening is within the technical requirements; (2) The surface hardness of the strengthening film 200 is not less than Hv800; (2) Wear resistance: Grind on a standard friction and wear testing machine for 30 minutes without exposing the workpiece; (3) Standard salt spray resistance time is not less than 72 hours; (4) The bonding strength meets the technical requirements of the mobile phone frame.

[0066] The following is an explanation based on experiments. The experimental methods may include:

[0067] (1) Workpiece deformation: Use an electric display vernier caliper with a resolution of 0.001 mm to detect; those that meet the technical requirements are qualified.

[0068] (2) Hardness test: SCTMC-HV-100(Z) Vickers microhardness tester measures the surface hardness of the sample film layer; the surface hardness is qualified if it is not less than HV800.

[0069] (3) Wear resistance test of film layer: The film layer on the surface of the workpiece was rubbed using an SFT-2M pin-on-disc friction and wear machine. The grinding material was GCr15, the test load was 5N, the rotation radius was 5mm, the rotation speed was 300r / min, and the friction time was 30min. The strengthening film was qualified if it did not peel off (the strengthening film did not separate from the workpiece) and did not show the bottom (the color of the workpiece was not exposed).

[0070] (4) Anti-rust performance test: The samples were subjected to salt spray test using a PS-120 precision salt spray tester. The test chamber temperature was 35°C and the salt spray was a 5% NaCl solution. The samples were qualified if the salt spray resistance time was greater than 72 hours.

[0071] (5) Film bonding strength: After the film layer is divided into 2mmX2mm grids, use different adhesive tapes to stick and pull the same grid position 5 times; if there is no layer falling off, it is qualified;

[0072] (6) Appearance inspection: The surface roughness should reach Ra0.005-Ra0.02, and no obvious spots can be observed by naked eyes under fluorescent light, which is qualified.

[0073] Comparative experiment:

[0074] Sample No. 1: workpiece surface oxygen-polar oxidation (oxidation in liquid medium followed by polishing);

[0075] Sample No. 2: workpiece surface oxygen-polarized (oxidized in a 400°C vacuum furnace and then polished);

[0076] Sample No. 3: the composite oxidation method provided in an embodiment of the present invention (composite oxidation followed by polishing).

[0077] Experimental results:

[0078] Table 1

[0079]

[0080] As shown in Table 1, in the prior art (No. 1 and No. 2), except for the deformation amount of No. 1 sample, the other indicators do not meet the requirements; all indicators of No. 2 sample meet the requirements. The strengthening film (i.e., aluminum oxide ceramic film) prepared by the composite oxidation method provided by the present invention has the advantages of high hardness, good wear resistance, strong corrosion resistance, good bonding strength and good appearance, and can meet the strengthening needs of mobile phone frames.

[0081] The embodiment also provides a mobile phone frame, which may include a frame body and a strengthening film. The strengthening film may be prepared by a composite oxidation method applicable to aluminum-based materials provided in the embodiment. The strengthening film may be an aluminum oxide ceramic film, which may be prepared by simultaneous reaction of anodization and ion sputtering. In addition, the thickness of the strengthening film is 5 μm to 8 μm.

[0082] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0083] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A composite oxidation method suitable for aluminum-based materials, characterized in that: The method comprises manufacturing a strengthening film on the surface of a workpiece, wherein the workpiece is an aluminum-based material, and manufacturing the strengthening film on the surface of the workpiece comprises: Connect the positive electrode of the source power supply to the vacuum furnace and to the ground, connect the negative electrode of the source power supply to the source target in the vacuum furnace, the waveform of the source power supply is a positive pulse, adjust the voltage of the source power supply to 400V to 500V, and adjust the frequency of the source power supply to 5KHz to 15KHz; The vacuum furnace is evacuated, and the temperature inside the vacuum furnace is maintained at 70° C. to 80° C.; Connect the negative electrode of the oxidation power source to the cathode plate in the vacuum furnace, the cathode plate is an aluminum-based material, connect the positive electrode of the oxidation power source to the workpiece, the distance between the cathode plate and the workpiece is greater than or equal to 50 mm, adjust the waveform of the oxidation power source to input a number of negative pulses after every 10 positive pulses, adjust the voltage of the oxidation power source to 600V to 700V, and adjust the frequency of the oxidation power source to 5KHz to 15KHz; The source power supply and the oxidation power supply are turned on, and oxygen is introduced into the vacuum furnace for 40 to 50 minutes.

2. The composite oxidation method suitable for aluminum-based materials according to claim 1, characterized in that: During the process of making the strengthening film on the surface of the workpiece, the vacuum furnace is evacuated to 0.05Pa to 0.1Pa.

3. The composite oxidation method suitable for aluminum-based materials according to claim 1, characterized in that: The distance between the cathode plate and the workpiece is set to 50 mm to 70 mm.

4. The composite oxidation method suitable for aluminum-based materials according to claim 1, characterized in that: In the process of making the strengthening film on the surface of the workpiece, the waveform of the oxidation power supply is 1 to 2 negative pulses after every 10 positive pulses.

5. The composite oxidation method suitable for aluminum-based materials according to claim 1, characterized in that: Before the strengthening film is formed on the surface of the workpiece, the composite oxidation method applicable to aluminum-based materials further includes cleaning the surface of the workpiece and the surface of the cathode plate, and the cleaning of the surface of the workpiece and the surface of the cathode plate includes: Connecting the positive electrode of the source power supply to the vacuum furnace and to the ground, and connecting the negative electrode of the source power supply to the source target in the vacuum furnace; The cathode plate is connected in series with the workpiece and connected to the negative electrode of the oxidation power source, and the positive electrode of the oxidation power source is connected to the vacuum furnace and grounded; Starting the source power supply, the waveform of the source power supply is a positive pulse, adjusting the voltage of the source power supply to 400V to 500V, adjusting the frequency of the source power supply to 5KHz to 15KHz, and evacuating the vacuum furnace; When the temperature of the vacuum furnace reaches 70°C to 80°C and the vacuum degree reaches 1Pa to 10Pa, argon gas is injected into the vacuum furnace and the oxidation power supply is started. The oxidation power supply waveform is a positive pulse, the voltage of the oxidation power supply is 500V to 600V, and the frequency of the oxidation power supply is 5KHz to 15KHz. The workpiece and the cathode plate are bombarded with argon gas for 10 minutes to 15 minutes.

6. The composite oxidation method applicable to aluminum-based materials according to any one of claims 1 to 5, characterized in that: The source target is tubular.

7. The composite oxidation method applicable to aluminum-based materials according to any one of claims 1 to 5, characterized in that: The source target is made of titanium alloy material.

8. A mobile phone frame, characterized in that: It comprises a frame body and a strengthening film, wherein the strengthening film is made by the composite oxidation method applicable to aluminum-based materials as described in any one of claims 1 to 7.

9. The mobile phone frame according to claim 8, characterized in that: The strengthening film includes an aluminum oxide ceramic layer.

10. The mobile phone frame according to claim 8 or 9, characterized in that: The thickness of the strengthening film is 5 μm to 8 μm.

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