Surface modification method of metal structural part and terminal equipment

Abstract

The invention relates to a surface modification method of a metal structural part and terminal equipment, the metal structural part comprises a first structural part and a second structural part which are connected, the first structural part is made of titanium and / or titanium alloy, and the second structural part is made of aluminum and / or aluminum alloy. According to the surface modification treatment method for the metal structural part, the anodic oxidation treatment, the first hole sealing treatment, the electrolytic treatment and the second hole sealing treatment are sequentially carried out on the metal structural part, so that a titanium oxide film layer on the surface of titanium or titanium alloy in the metal structural part can be effectively removed; and meanwhile, a compact aluminum oxide film layer can be formed on the surface of aluminum or aluminum alloy in the metal structural part, so that the wear resistance and corrosion resistance of the metal structural part can be improved.

Description

Technical Field

[0001] This invention relates to the field of surface modification technology, and more particularly to surface modification methods and end-use equipment for metal structural components. Background Technology

[0002] Titanium alloys possess characteristics such as lightweight, high strength, high wear resistance, and high corrosion resistance, making them widely used in aerospace, medical devices, chemical engineering, and marine engineering. However, the application of titanium alloys alone is limited by their high price and processing performance. Aluminum alloys, on the other hand, offer advantages such as lightweight, good electrical and thermal conductivity, and low cost, and are already widely used in aerospace, shipbuilding, and transportation. Combining titanium and aluminum alloys to form titanium-aluminum metal structural components can fully utilize the characteristics and advantages of both materials. However, aluminum alloys are prone to corrosion in high-temperature and humid environments, leading to performance degradation. Therefore, appropriate surface modification treatment is usually required for titanium-aluminum metal structural components to form an aluminum oxide film on the surface of the aluminum metal structural components, thereby improving their corrosion resistance and wear resistance.

[0003] Currently, anodizing is a common method for surface modification of titanium-aluminum metal structural components, forming an aluminum oxide film on the aluminum alloy surface. However, during this process, a titanium oxide film also forms on the surface of the titanium structural components, which adversely affects the adhesion of the metal surface and therefore needs to be removed.

[0004] In the prior art, abrasive blasting is used to remove the oxide layer on the surface of titanium or titanium alloy. However, this method is limited by the shape requirements of the product being treated, and the removal effect on the oxide layer in the depressions, corners or holes of the product surface is poor.

[0005] Therefore, how to effectively remove the oxide layer from the surface of titanium or titanium alloys is a problem that still needs to be solved. Summary of the Invention

[0006] This application provides a surface modification method and terminal equipment for metal structural components. By sequentially performing anodizing, first sealing, electrolytic treatment, and second sealing treatment on the metal structural components, the titanium oxide film layer on the surface of titanium or titanium alloy in the metal structural components can be effectively removed. At the same time, a dense aluminum oxide film layer can be formed on the surface of aluminum or aluminum alloy in the metal structural components, thereby improving the wear resistance and corrosion resistance of the metal structural components.

[0007] In a first aspect, this application provides a method for surface modification of a metal structural component, the metal structural component comprising a first structural component and a second structural component connected to each other, the first structural component being made of titanium and / or titanium alloy, and the second structural component being made of aluminum and / or aluminum alloy, the surface modification method comprising the following steps:

[0008] The metal structural components are placed in a sulfuric acid electrolyte for anodic oxidation treatment to form a titanium oxide film on the surface of the first structural component and an aluminum oxide film on the surface of the second structural component.

[0009] The metal structural component after anodizing is then subjected to a first sealing process.

[0010] The metal structural component after the first sealing treatment is placed in a chlorogenic acid electrolyte for electrolytic treatment to remove the titanium dioxide film layer; wherein the chlorogenic acid electrolyte comprises the following components in the following mass percentages: chlorogenic acid 15% to 20%, silicate 2% to 5%, and the balance being water;

[0011] The metal structural component after electrolytic treatment undergoes a second sealing process.

[0012] In some embodiments, the chlorogenic acid electrolyte comprises the following components by mass percentage: chlorogenic acid 17%–19% and silicate 3.5%–4%.

[0013] In some embodiments, the chlorogenic acid electrolyte further includes benzotriazole at a mass ratio of 3% to 5%.

[0014] In some embodiments, the chlorogenic acid electrolyte further includes 5% to 10% triethanolamine by mass.

[0015] In some embodiments, the silicate includes sodium silicate and / or sodium metasilicate.

[0016] In some embodiments, the thickness of the titanium oxide film is 0.1 μm to 0.2 μm.

[0017] In some embodiments, the voltage of the electrolysis treatment is 7.5V to 8.5V, the electrolysis treatment time is 8min to 10min, and the electrolysis treatment temperature is 67℃ to 73℃.

[0018] In some embodiments, the anode of the electrolytic treatment is the metal structural component, and the cathode of the electrolytic treatment is a graphite electrode.

[0019] In some embodiments, after the electrolytically treated metal structural component undergoes a second sealing process, the porosity of the alumina film is 10% to 15%, and the thickness of the alumina film is 8 μm to 12 μm.

[0020] In a second aspect, this application provides a terminal device, the terminal device comprising a metal structural component prepared according to the surface modification method for metal structural components described in the first aspect.

[0021] Compared with the prior art, the technical solution of this application has at least the following beneficial effects:

[0022] The surface modification method for metal structural components provided in this application includes a first structural component and a second structural component connected to each other. The first structural component is made of titanium and / or titanium alloy, and the second structural component is made of aluminum and / or aluminum alloy. First, the metal structural components are anodized to form a titanium oxide film on the surface of the first structural component and an aluminum oxide film on the surface of the second structural component. Second, the anodized metal structural components undergo a first sealing treatment. This first sealing treatment closes some of the pores in the aluminum oxide film, thereby improving the anti-fouling ability, corrosion resistance, and wear resistance of the aluminum oxide film. Third, the metal structural components after the first sealing treatment are placed in a chlorogenic acid electrolyte for electrolysis. The chlorogenic acid hydrolyzes to release hydrogen ions, making the electrolysis environment acidic. Under this environment, electrolysis can... The titanium dioxide film on the surface of the first structural component is rapidly dissolved and removed. Simultaneously, during electrolysis, the hydroxide ions generated by the reduction of water molecules adsorb and combine with the alumina film formed on the surface of the second structural component, undergoing a passivation reaction to generate a denser and more stable alumina film. Furthermore, sodium silicate in the chlorogenic acid electrolyte ionizes during electrolysis, releasing silicate ions that accumulate on the surface of the alumina film, forming a denser aluminum silicate composite oxide layer. This reduces corrosion of the second structural component and the alumina film formed on its surface during electrolysis. Finally, the electrolyzed metal structural component undergoes a second sealing treatment. This second sealing process further seals the pores in the alumina film formed on the surface of the second structural component, thereby further improving the wear resistance and corrosion resistance of the alumina film. Attached Figure Description

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] Figure 1 A process flow diagram of the surface modification method for metal structural parts provided in the embodiments of this application;

[0025] Figure 2 This is a schematic diagram of the electrolytic reaction of a metal structural component provided in an embodiment of this application. Detailed Implementation

[0026] To better understand the technical solution of the present invention, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0027] It should be understood that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0028] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0029] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0030] In a first aspect, this application provides a surface modification method for a metal structural component, the metal structural component comprising a first structural component and a second structural component connected to each other, the first structural component being made of titanium and / or titanium alloy, and the second structural component being made of aluminum and / or aluminum alloy, such as... Figure 1 As shown, the surface modification method includes the following steps:

[0031] Step S100: The metal structural component is placed in a sulfuric acid electrolyte for anodic oxidation treatment to form a titanium oxide film on the surface of the first structural component and an aluminum oxide film on the surface of the second structural component.

[0032] Step S200: Perform the first sealing treatment on the anodized metal structural parts;

[0033] Step S300: The metal structural component after the first sealing treatment is placed in a chlorogenic acid electrolyte for electrolytic treatment to remove the titanium oxide film layer; wherein, the chlorogenic acid electrolyte includes the following components in the following mass percentages: chlorogenic acid 15% to 20%, silicate 2% to 5%, and the balance water;

[0034] Step S400: Perform a second sealing process on the electrolytically treated metal structural parts.

[0035] In the above scheme, the metal structural component includes a first structural component and a second structural component connected together. The first structural component is made of titanium and / or titanium alloy, and the second structural component is made of aluminum and / or aluminum alloy. First, the metal structural components are anodized to form a titanium oxide film on the surface of the first structural component and an aluminum oxide film on the surface of the second structural component. Next, the anodized metal structural component undergoes a first sealing treatment. This first sealing treatment closes some of the pores in the aluminum oxide film, thereby improving the anti-fouling ability, corrosion resistance, and wear resistance of the aluminum oxide film. Then, the metal structural component after the first sealing treatment is placed in a chlorogenic acid electrolyte for electrolysis. The chlorogenic acid hydrolyzes to release hydrogen ions, making the electrolytic environment acidic. Under this environment, electrolysis can remove impurities from the surface of the first structural component. The titanium dioxide film is rapidly dissolved and removed. Simultaneously, the hydroxide ions generated during the reduction of water molecules in the electrolysis process adsorb and combine with the alumina film formed on the surface of the second structural component, resulting in passivation and the formation of a denser and more stable alumina film. Furthermore, sodium silicate in the chlorogenic acid electrolyte ionizes into silicate ions during electrolysis, which accumulate on the surface of the alumina film, forming a denser aluminum silicate composite oxide layer. This reduces corrosion of the second structural component and the alumina film formed on its surface during electrolysis. Finally, the electrolyzed metal structural component undergoes a second sealing treatment. This second sealing process further seals the pores in the alumina film formed on the surface of the second structural component, thereby further improving the wear resistance and corrosion resistance of the alumina film.

[0036] In step S100, the metal structural component is placed in a sulfuric acid electrolyte for anodic oxidation treatment to form a titanium oxide film on the surface of the first structural component and an aluminum oxide film on the surface of the second structural component.

[0037] In some embodiments, the first structural member is made of titanium and / or titanium alloy, and may further be titanium aluminum alloy, such as TC4 titanium alloy.

[0038] In some embodiments, the second structural member is made of aluminum and / or aluminum alloys, and may further be an aluminum alloy such as Al6013.

[0039] In some embodiments, the sulfuric acid electrolyte comprises the following components in the following mass percentages: 8% to 50% sulfuric acid, 15% to 25% ethylene glycol, and the balance being water.

[0040] Specifically, the mass percentage of sulfuric acid in the sulfuric acid electrolyte can be 8%, 10%, 12%, 15%, 18%, 20%, 25%, 30%, 32%, 35%, 38%, 40%, 45%, 48%, or 50%, etc., and can be selected according to actual needs. No restrictions are imposed here.

[0041] The specific mass percentage of ethylene glycol in the sulfuric acid electrolyte can be 15%, 16%, 17%, 18%, 19%, 20%, 22%, or 25%, etc., and is not limited here.

[0042] In some embodiments, the voltage for anodizing is 28V to 32V, specifically 28V, 28.5V, 29V, 30V, 31V, 31.5V or 32V, etc., and of course, other values ​​within the above range are also possible, without limitation.

[0043] In some embodiments, the anodizing treatment time is 40 min to 70 min, specifically 40 min, 45 min, 50 min, 55 min, 60 min, 61 min, 62 min, 63 min, 64 min, 65 min, 66 min, 67 min, 68 min, 69 min or 70 min, etc. Of course, other values ​​within the above range are also possible, and no limitation is made here.

[0044] In some embodiments, the temperature of the anodizing treatment is 3℃ to 7℃, specifically 3℃, 3.5℃, 4℃, 4.5℃, 5℃, 5.5℃, 6℃ or 7℃, etc., and of course, other values ​​within the above range are also possible, which are not limited here.

[0045] This application allows for the acquisition of alumina and titanium oxide films of varying thicknesses by adjusting process parameters (such as voltage, time, and temperature) during the anodizing process.

[0046] In some embodiments, the thickness of the alumina film obtained by anodizing is 8 μm to 12 μm, specifically 8 μm, 8.5 μm, 9 μm, 9.5 μm, 10 μm, 10.5 μm, 11 μm, 11.5 μm, or 12 μm, etc., and of course, other values ​​within the above range are also possible and are not limited here. It is understood that an alumina film thickness within the above range can effectively reduce the contact between corrosive media and metal structural components, reducing the possibility of corrosion and thus improving the corrosion resistance of the metal structural components; at the same time, it can give the alumina film a higher hardness, which is beneficial to improving the wear resistance of the metal structural components.

[0047] In some embodiments, the thickness of the titanium dioxide film obtained by anodic oxidation is 0.1 μm to 0.2 μm, specifically 0.1 μm, 0.11 μm, 0.12 μm, 0.13 μm, 0.14 μm, 0.15 μm, 0.16 μm, 0.17 μm, 0.18 μm or 0.2 μm, etc. Of course, other values ​​within the above range are also possible, and are not limited here.

[0048] Step S200: Perform the first sealing treatment on the anodized metal structural parts.

[0049] In the above scheme, the first sealing treatment can seal some of the pores in the alumina film, thereby improving the anti-pollution ability, corrosion resistance and wear resistance of the alumina film.

[0050] In some embodiments, the first sealing process specifically includes: immersing the anodized metal structural component in a sealing agent at 85°C to 95°C for the first sealing process, followed by cleaning and drying.

[0051] In some embodiments, the sealing agent includes a nickel acetate solution. It is understood that when a nickel acetate solution is used as a sealing agent, when the anodized metal structural component is immersed in the nickel acetate solution, nickel ions in the solution are adsorbed into the pores of the alumina film and undergo a hydrolysis reaction under appropriate conditions to generate nickel hydroxide precipitate. The generated nickel hydroxide precipitate gradually fills the pores of the alumina film, effectively sealing the micropores of the alumina film, reducing porosity, and improving the overall density of the alumina film. This reduces the penetration of external corrosive media into the secondary structural component, thereby enhancing the corrosion resistance of the secondary structural component. Simultaneously, it makes the alumina film structure more stable and improves the wear resistance of the alumina film.

[0052] Specifically, the temperature for the first sealing treatment can be 85℃, 86℃, 87℃, 88℃, 89℃, 90℃, 91℃, 92℃, 93℃, 94℃ or 95℃, etc., which can be selected according to actual needs, and no limitation is made here.

[0053] In some implementations, the time for the first sealing process is 50 min to 60 min, specifically 50 min, 51 min, 52 min, 53 min, 54 min, 55 min, 56 min, 57 min, 58 min, 59 min or 60 min, etc. Of course, other values ​​within the above range are also possible, and no limitation is made here.

[0054] In some embodiments, the mass concentration of the sealing agent is 8 g / L to 12 g / L, specifically 8 g / L, 9 g / L, 10 g / L, 11 g / L, or 12 g / L, etc., and of course, other values ​​within the above range are also possible, which are not limited here. Step S300: The metal structural component after the first sealing treatment is placed in a chlorogenic acid electrolyte for electrolytic treatment to remove the titanium oxide film layer; wherein, the chlorogenic acid electrolyte includes the following components in the following mass percentages: chlorogenic acid 15% to 20%, silicate 2% to 5%, and the balance water.

[0055] In the above scheme, chlorogenic acid hydrolyzes to release hydrogen ions, making the electrolysis environment acidic. Under this environment, electrolysis can quickly dissolve and remove the titanium dioxide film layer on the surface of the first structural component, thereby improving the adhesion of the first metal structural component surface. At the same time, the hydroxide ions generated by the reduction of water molecules during electrolysis will adsorb and combine with the alumina film layer formed on the surface of the second structural component, and passivate to generate a denser and more stable alumina film layer. In addition, sodium silicate in the chlorogenic acid electrolyte ionizes to release silicate ions during electrolysis, which accumulate on the surface of the alumina film layer and form a denser aluminum silicate salt composite oxide layer on the surface of the alumina film layer, thereby reducing the corrosion of the second structural component and the alumina film layer formed on the surface of the second structural component during electrolysis.

[0056] Furthermore, this application utilizes chlorogenic acid electrolyte to electrolyze the metal structural component, which rapidly and efficiently removes the titanium oxide film layer on the surface of the second structural component. The removal of the titanium oxide film layer is not limited by the surface morphology of the product; it can effectively remove the titanium oxide film layer from depressions, corners, or holes on the product surface. The surface modification method for metal structural components in this application has high efficiency in removing the titanium oxide film layer on the surface of the metal structural component and low production cost. In some embodiments, the mass percentage of chlorogenic acid in the chlorogenic acid electrolyte is 15% to 20%, specifically 15%, 16%, 17%, 18%, 19%, or 20%, etc., and other values ​​within the above range are also possible and are not limited here. It is understood that using chlorogenic acid as the electrolyte in the electrolytic treatment can effectively remove the titanium oxide film layer formed on the surface of the first structural component. Simultaneously, chlorogenic acid has weak corrosiveness, which can reduce corrosion of the alumina film layer formed on the surface of the second structural component. Furthermore, during the electrolytic process, chlorogenic acid decomposes into caffeic acid and quinic acid. These two acids release a large number of hydroxyl groups, which can adsorb onto the surface of the alumina film to form a passivation protection, isolating the alumina film surface from contact with the electrolyte, thereby further reducing the corrosion of the alumina film during electrolysis. Preferably, the mass percentage of chlorogenic acid is 17% to 19%.

[0057] In some embodiments, the silicate includes sodium silicate and / or sodium metasilicate. It is understood that in the electrolyte, the silicate adsorbs onto the surface of the alumina film to form a protective layer, thereby isolating the alumina film from the electrolyte and reducing surface corrosion of the alumina film.

[0058] In some embodiments, the mass percentage of silicate in the chlorogenic acid electrolyte is 2% to 5%, specifically 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5%, etc., and other values ​​within the above range are also possible, without limitation. Preferably, the mass percentage of silicate is 3.5% to 4%.

[0059] In some embodiments, the chlorogenic acid electrolyte further includes benzotriazole at a mass ratio of 3% to 5%. The specific mass ratio of benzotriazole can be 3%, 3.5%, 4%, 4.1%, 4.3%, 4.5%, 4.6%, 4.8%, or 5%, etc., and is not limited here. It is understood that adding benzotriazole to the electrolyte as a corrosion inhibitor can not only effectively remove the titanium dioxide film layer, but also reduce the corrosion of the alumina film layer during electrolysis.

[0060] In some embodiments, the chlorogenic acid electrolyte also includes 5% to 10% triethanolamine by mass. The specific mass percentage of triethanolamine can be 5%, 6%, 7%, 8%, 8.5%, 9%, 9.5%, or 10%, etc., and is not limited here.

[0061] In some embodiments, the thickness of the titanium oxide film is 0.1 μm to 0.2 μm, specifically 0.1 μm, 0.11 μm, 0.12 μm, 0.13 μm, 0.14 μm, 0.15 μm, 0.16 μm, 0.17 μm, 0.18 μm or 0.2 μm, etc. Of course, other values ​​within the above range are also possible, and are not limited here.

[0062] In some implementations, the voltage for electrolytic treatment is 7.5V to 8.5V, specifically 7.5V, 7.6V, 7.8V, 8.0V, 8.1V, 8.2V, 8.3V, 8.4V, or 8.5V, etc. Of course, other values ​​within the above range are also possible, and no limitation is made here.

[0063] In some implementations, the electrolysis treatment time is 8 min to 10 min, specifically 8 min, 8.5 min, 9 min, 9.2 min, 9.5 min, 9.8 min or 10 min, etc. Of course, other values ​​within the above range are also possible, and no limitation is made here.

[0064] In some embodiments, the electrolysis temperature is 67°C to 73°C, specifically 67°C, 68°C, 69°C, 70°C, 71°C, 72°C or 73°C, etc., and of course other values ​​within the above range are also possible, which are not limited here.

[0065] It should be noted that in this application, for titanium oxide film layers of different thicknesses, the titanium oxide film layer on the surface of the first structural component can be removed quickly and efficiently by adjusting the process parameters of electrolytic treatment (such as voltage, time, temperature and electrolyte concentration), thereby improving the removal efficiency.

[0066] In some implementations... Figure 2 This is a schematic diagram of the electrolytic reaction of a metal structural component, such as... Figure 2 As shown, the anode of the electrolytic treatment is a metal structural component, and the cathode of the electrolytic treatment is a graphite electrode.

[0067] The reaction equations for electrolytic treatment are as follows:

[0068] ionization of chlorogenic acid:

[0069] Main reaction for TiO2 dissolution: During the electrolytic treatment, chlorogenic acid hydrolyzes to produce hydrogen ions, making the electrolytic environment acidic. Under this environment, titanium dioxide is dissolved and removed by the action of external force.

[0070] Furthermore, the first structural component and the second structural component in the metal structure undergo a galvanic cell reaction, with the first structural component (i.e., titanium and / or titanium alloy) as the anode and the second structural component (i.e., aluminum and / or aluminum alloy) as the cathode. The reaction equation is as follows:

[0071] Anode: Ti 4+ +2e - →Ti 2+ (Main)ψ θ = -0.74V

[0072] 2H2O+2e - →2OH - +H2(sub)ψ θ =0V

[0073] Cathode: H₂O + OH⁻ - +Al₂O₃→Al(OH) X H₂O → γ-Al₂O₃ (main)

[0074] During the galvanic cell reaction, tetravalent titanium in titanium oxide is reduced to divalent titanium and removed. Simultaneously, water electrolysis generates hydroxide ions and hydrogen gas. The hydroxide ions generated at the anode migrate to the cathode, where they combine with Al₂O₃ and undergo a passivation reaction to form more stable γ-Al₂O₃. Meanwhile, silicates in the electrolyte ionize, releasing silicate ions that accumulate on the Al₂O₃ surface to form a protective layer (aluminum silicate), inhibiting OH-. - H + The reaction with γ-Al2O3 can effectively reduce the corrosion of the second structural component (i.e., aluminum and / or aluminum alloy) and the alumina film during electrolysis.

[0075] Step S400: Perform a second sealing process on the electrolytically treated metal structural parts.

[0076] In the above solution, the pores in the alumina film layer formed on the surface of the second structural component can be further sealed by the second sealing treatment, thereby further improving the wear resistance and corrosion resistance of the alumina film layer.

[0077] In some embodiments, the second sealing process specifically includes: immersing the electrolytically treated metal structural component in a sealing agent at 85°C to 95°C for a second sealing process, followed by cleaning and drying.

[0078] In some embodiments, the sealing agent includes a nickel acetate solution.

[0079] Specifically, the temperature for the first sealing treatment can be 85℃, 86℃, 87℃, 88℃, 89℃, 90℃, 91℃, 92℃, 93℃, 94℃ or 95℃, etc., which can be selected according to actual needs, and no limitation is made here.

[0080] In some implementations, the time for the first sealing process is 25 min to 35 min, specifically 25 min, 26 min, 27 min, 28 min, 29 min, 30 min, 31 min, 32 min, 33 min, 34 min or 35 min, etc. Of course, other values ​​within the above range are also possible, and no limitation is made here.

[0081] In some embodiments, the concentration of the sealing agent is 8 g / L to 12 g / L, specifically 8 g / L, 9 g / L, 10 g / L, 11 g / L or 12 g / L, etc. Of course, other values ​​within the above range are also possible, and are not limited here.

[0082] In some embodiments, after the electrolytically treated metal structural parts undergo a second sealing treatment, the porosity of the alumina film layer is 10% to 15%, specifically 10%, 10.5%, 11%, 11.5%, 12%, 13%, 13.5%, 14%, or 15%, etc., and of course, other values ​​within the above range are also possible, without limitation. It is understood that if the porosity of the alumina film layer after the second sealing treatment is within the above range, it indicates that the pores on the surface and inside of the alumina film layer are effectively filled, improving the density of the alumina film layer. This reduces the penetration of corrosive media into the surface of the metal structural parts, improving their corrosion resistance. Simultaneously, the increased density of the alumina film layer reduces surface defects, making the surface smoother, reducing friction contact areas, and improving the wear resistance of the alumina film layer surface.

[0083] In some embodiments, after the electrolytically treated metal structural components undergo a second sealing treatment, the thickness of the alumina film is 8μm to 12μm, specifically 8μm, 8.5μm, 9μm, 9.5μm, 10μm, 10.5μm, 11μm, 11.5μm, or 12μm, etc., and of course, other values ​​within the above range are also possible and are not limited here. It is understood that an alumina film thickness within the above range can effectively reduce the contact between corrosive media and the metal structural components, reducing the possibility of corrosion and thus improving the corrosion resistance of the metal structural components; at the same time, it can give the alumina film a higher hardness, which is beneficial to improving the wear resistance of the metal structural components.

[0084] In a second aspect, this application provides a terminal device, the terminal device comprising a metal structural component prepared according to the surface modification method for metal structural components described in the first aspect.

[0085] Example 1

[0086] (1) Prepare metal structural components, including a first structural component and a second structural component that are connected to each other. The first structural component is made of TC4 titanium alloy and the second structural component is made of aluminum alloy (Al6013).

[0087] (2) The metal structural parts are placed in a sulfuric acid electrolyte for anodizing treatment to form a titanium oxide film layer (thickness of 0.15 μm) on the surface of the first structural part and an aluminum oxide film layer (thickness of 10 μm) on the surface of the second structural part; wherein, the sulfuric acid electrolyte includes: 10% sulfuric acid, 20% ethylene glycol and the balance water; the voltage of the anodizing treatment is 30V, the time is 60min, and the temperature is 5℃.

[0088] (3) Immerse the metal structural parts treated in step (2) at 90°C in a nickel acetate solution with a concentration of 10 g / L for 65 min for the first sealing treatment, then clean and dry.

[0089] (4) The metal structural component treated in step (3) is placed in a chlorogenic acid electrolyte for electrolytic treatment to remove the titanium oxide film layer. The metal structural component is used as the anode and the graphite electrode is used as the cathode. The chlorogenic acid electrolyte includes 17.5% chlorogenic acid, 3.5% sodium silicate, 4% benzotriazole, 7.5% triethanolamine and the balance water. The voltage of the electrolytic treatment is 8V, the time is 9min and the temperature is 70℃.

[0090] (5) Immerse the metal structural parts treated in step (4) at 90°C in a nickel acetate solution with a concentration of 10 g / L for 30 min for a second sealing treatment, then clean and dry.

[0091] In this embodiment, after the above processing steps, the porosity of the alumina film is 12.5%, the thickness of the alumina film is 10 μm, and the removal rate of the titanium oxide film is 100%.

[0092] Example 2

[0093] Unlike Example 1:

[0094] (2) The metal structural parts are placed in a sulfuric acid electrolyte for anodizing treatment to form a titanium oxide film layer (thickness of 0.1 μm) on the surface of the first structural part and an aluminum oxide film layer (thickness of 8 μm) on the surface of the second structural part; wherein, the sulfuric acid electrolyte includes: 40% sulfuric acid, 20% ethylene glycol and the balance water; the voltage of the anodizing treatment is 28V, the time is 60min, and the temperature is 5℃.

[0095] In this embodiment, after the above processing steps, the porosity of the alumina film is 15%, the thickness of the alumina film is 8 μm, and the removal rate of the titanium oxide film is 100%.

[0096] Example 3

[0097] Unlike Example 1:

[0098] (2) The metal structural parts are placed in a sulfuric acid electrolyte for anodizing treatment to form a titanium oxide film layer (thickness of 0.2 μm) on the surface of the first structural part and an aluminum oxide film layer (thickness of 12 μm) on the surface of the second structural part; wherein, the sulfuric acid electrolyte includes: 40% sulfuric acid, 20% ethylene glycol and the balance water; the voltage of the anodizing treatment is 32V, the time is 60min, and the temperature is 5℃.

[0099] In this embodiment, after the above processing steps, the porosity of the alumina film is 10%, the thickness of the alumina film is 12 μm, and the removal rate of the titanium oxide film is 100%.

[0100] Example 4

[0101] Unlike Example 1:

[0102] (2) The metal structural parts are placed in a sulfuric acid electrolyte for anodizing treatment to form a titanium oxide film layer (thickness of 0.2 μm) on the surface of the first structural part and an aluminum oxide film layer (thickness of 12 μm) on the surface of the second structural part; wherein, the sulfuric acid electrolyte includes: 40% sulfuric acid, 20% ethylene glycol and the balance water; the voltage of the anodizing treatment is 30V, the time is 65min, and the temperature is 5℃.

[0103] In this embodiment, after the above processing steps, the porosity of the alumina film is 15%, the thickness of the alumina film is 12 μm, and the removal rate of the titanium oxide film is 100%.

[0104] Example 5

[0105] Unlike Example 1:

[0106] (2) The metal structural parts are placed in a sulfuric acid electrolyte for anodizing treatment to form a titanium oxide film layer (thickness of 0.2 μm) on the surface of the first structural part and an aluminum oxide film layer (thickness of 12 μm) on the surface of the second structural part; wherein, the sulfuric acid electrolyte includes: 8% sulfuric acid, 20% ethylene glycol and the balance water; the voltage of the anodizing treatment is 30V, the time is 65min, and the temperature is 5℃.

[0107] In this embodiment, after the above processing steps, the porosity of the alumina film is 10%, the thickness of the alumina film is 12 μm, and the removal rate of the titanium oxide film is 100%.

[0108] Example 6

[0109] Unlike Example 1:

[0110] (2) The metal structural parts are placed in a sulfuric acid electrolyte for anodizing treatment to form a titanium oxide film layer (thickness of 0.1 μm) on the surface of the first structural part and an aluminum oxide film layer (thickness of 8 μm) on the surface of the second structural part; wherein, the sulfuric acid electrolyte includes: 30% sulfuric acid, 20% ethylene glycol and the balance water; the voltage of the anodizing treatment is 30V, the time is 40min, and the temperature is 5℃.

[0111] In this embodiment, after the above processing steps, the porosity of the alumina film is 15%, the thickness of the alumina film is 8 μm, and the removal rate of the titanium oxide film is 100%.

[0112] Example 7

[0113] Unlike Example 1:

[0114] The voltage for electrolysis in step (4) is 7.5V.

[0115] In this embodiment, after the above processing steps, the porosity of the alumina film is 13%, the thickness of the alumina film is 10 μm, and the removal rate of the titanium oxide film is 100%.

[0116] Example 8

[0117] Unlike Example 1:

[0118] The voltage for electrolysis in step (4) is 8.5V.

[0119] In this embodiment, after the above processing steps, the porosity of the alumina film is 14%, the thickness of the alumina film is 10 μm, and the removal rate of the titanium oxide film is 100%.

[0120] Example 9

[0121] Unlike Example 1:

[0122] The electrolysis reaction time in step (4) is 8 minutes.

[0123] In this embodiment, after the above processing steps, the porosity of the alumina film is 11%, the thickness of the alumina film is 10 μm, and the removal rate of the titanium oxide film is 100%.

[0124] Example 10

[0125] Unlike Example 1:

[0126] The electrolysis reaction in step (4) takes 10 minutes.

[0127] In this embodiment, after the above processing steps, the porosity of the alumina film is 14%, the thickness of the alumina film is 10 μm, and the removal rate of the titanium oxide film is 100%.

[0128] Example 11

[0129] Unlike Example 1:

[0130] In step (4), chlorogenic acid accounts for 15% of the total mass.

[0131] In this embodiment, after the above processing steps, the porosity of the alumina film is 12%, the thickness of the alumina film is 10 μm, and the removal rate of the titanium oxide film is 100%.

[0132] Example 12

[0133] Unlike Example 1:

[0134] In step (4), chlorogenic acid accounts for 20% of the total mass.

[0135] In this embodiment, after the above processing steps, the porosity of the alumina film is 14%, the thickness of the alumina film is 10 μm, and the removal rate of the titanium oxide film is 100%.

[0136] Comparative Example 1

[0137] The difference from Example 1 is as follows:

[0138] Step (4) The mass percentage of chlorogenic acid in the chlorogenic acid electrolyte is 10%.

[0139] In this embodiment, after the above processing steps, the porosity of the alumina film is 11%, the thickness of the alumina film is 10 μm, and the removal rate of the titanium oxide film is 60%.

[0140] Comparative Example 2

[0141] The difference from Example 1 is as follows:

[0142] Step (4) The mass percentage of chlorogenic acid in the chlorogenic acid electrolyte is 30%.

[0143] In this embodiment, after the above processing steps, the porosity of the alumina film is 17%, the thickness of the alumina film is 10 μm, and the removal rate of the titanium oxide film is 100%.

[0144] Comparative Example 3

[0145] The difference from Example 1 is as follows:

[0146] In step (4), sodium silicate is not added to the chlorogenic acid electrolyte.

[0147] In this embodiment, after the above processing steps, the porosity of the alumina film is 15%, the thickness of the alumina film is 10 μm, and the removal rate of the titanium oxide film is 80%.

[0148] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for surface modification of metal structural components, characterized in that, The metal structural component includes a first structural component and a second structural component connected to each other. The first structural component is made of titanium and / or titanium alloy, and the second structural component is made of aluminum and / or aluminum alloy. The surface modification method includes the following steps: The metal structural components are placed in a sulfuric acid electrolyte for anodic oxidation treatment to form a titanium oxide film on the surface of the first structural component and an aluminum oxide film on the surface of the second structural component. The metal structural component after anodizing is then subjected to a first sealing process. The metal structural component after the first sealing treatment is placed in a chlorogenic acid electrolyte for electrolytic treatment to remove the titanium dioxide film layer; wherein the chlorogenic acid electrolyte comprises the following components in the following mass percentages: chlorogenic acid 15% to 20%, silicate 2% to 5%, and the balance being water; The metal structural component after electrolytic treatment undergoes a second sealing process.

2. The surface modification method for metal structural components according to claim 1, characterized in that, The chlorogenic acid electrolyte comprises the following components by mass percentage: chlorogenic acid 17%–19% and silicate 3.5%–4%.

3. The surface modification method for metal structural components according to claim 1, characterized in that, The chlorogenic acid electrolyte also includes benzotriazole at a mass ratio of 3% to 5%.

4. The surface modification method for metal structural parts according to claim 1, characterized in that, The chlorogenic acid electrolyte also includes triethanolamine at a mass ratio of 5% to 10%.

5. The surface modification method for metal structural components according to claim 1 or 2, characterized in that, The silicate includes sodium silicate and / or sodium metasilicate.

6. The surface modification method for metal structural parts according to claim 1, characterized in that, The thickness of the titanium dioxide film is 0.1 μm to 0.2 μm.

7. The surface modification method for metal structural parts according to claim 6, characterized in that, The voltage of the electrolysis treatment is 7.5V to 8.5V, the electrolysis treatment time is 8min to 10min, and the electrolysis treatment temperature is 67℃ to 73℃.

8. The surface modification method for metal structural parts according to claim 1, characterized in that, The anode of the electrolytic treatment is the metal structural component, and the cathode of the electrolytic treatment is a graphite electrode.

9. The surface modification method for metal structural parts according to claim 1, characterized in that, After the electrolytically treated metal structural component undergoes a second sealing process, the porosity of the alumina film is 10% to 15%, and the thickness of the alumina film is 8 μm to 12 μm.

10. A terminal device, characterized in that, The terminal device includes a metal structural component prepared by the surface modification method of the metal structural component according to any one of claims 1 to 9.

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