Method for obtaining corrosion-resistant film on surface of aluminum alloy

Abstract

The invention discloses a method for obtaining a corrosion-resistant film on an aluminum alloy surface, and belongs to the technical field of aluminum alloy surface chemical treatment. A method for obtaining a corrosion-resistant film on the surface of an aluminum alloy comprises the following steps that S1, a Li2CO3 aqueous solution is prepared, the pH is adjusted to be 10.5-11.5, and the aluminum alloy is placed in the Li2CO3 aqueous solution to be soaked; s2, the aluminum alloy treated in the step S1 is soaked in a composite corrosion inhibitor solution, and a corrosion-resistant film is obtained on the surface of the aluminum alloy; the composite corrosion inhibitor solution is an aqueous solution of supersaturated calcium hydroxide and a corrosion inhibitor; and the corrosion inhibitor is benzotriazole and / or sodium 4-aminobenzoate. According to the method for obtaining the corrosion-resistant film on the surface of the aluminum alloy, the corrosion-resistant film can be obtained on the surface of the aluminum alloy at normal temperature and normal pressure, and the corrosion resistance of the aluminum alloy can be remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of chemical treatment technology for aluminum alloy surfaces, and more specifically, to a method for obtaining a corrosion-resistant film on the surface of an aluminum alloy. Background Technology

[0002] 7075 aluminum alloy is an Al-Zn-Mg-Cu series ultra-hard aluminum alloy with a density of approximately 2.8 g / cm³. 3 With a tensile strength exceeding 500 MPa, 7075 aluminum alloy can be used as a high-end core material in aerospace, automotive, and marine industries. However, in specific applications such as marine and aerospace, corrosive substances in the environment, such as chloride salts, fuels, de-icing fluids, and hydraulic oils, can corrode 7075 aluminum alloy, limiting its safety, shortening its service life, and increasing maintenance costs.

[0003] Currently, there is relatively much research on using layered bimetallic hydroxides (LDHs) to mitigate metal corrosion, but most of it focuses on LDH powder technology. For example, the invention patent "Corrosion-resistant waterborne epoxy coating for graphene-hydrotalcite nanocontainers and its preparation method" uses LDH loaded with metavanadate corrosion inhibitors and improves its dispersibility with graphene oxide, which enhances the anti-corrosion performance after being added to waterborne epoxy resin. The invention patent "A protective coating for aluminum alloy heat exchange tubes and its preparation method" involves MgAlCe-BTC-LDH filler to achieve oxidation resistance and corrosion resistance in aluminum alloy heat exchange tubes.

[0004] LDH corrosion-resistant films have the advantage of improving corrosion inhibition efficiency by utilizing steric effects compared to LDH powder, and there has been a certain amount of research on this topic. For example, the invention patent "Preparation Method of Superhydrophobic Coating on Aluminum Alloy Surface" prepares a superhydrophobic coating on the surface of aluminum alloy based on Zn-Al-LDH film and stearic acid, but the preparation process involves high temperatures of 400-550℃ and calcination. The invention patent "A Layered Bimetallic Hydroxide with Positively Charged Species Embedded in Interlayers and Its Preparation Method" prepares a Mefp-1 modified Zn-Al-LDH film on the surface of 7075 aluminum alloy, but the preparation process also involves high temperatures of 50-100℃. The invention patent "A Method for Graded Sealing of Lithium Salts in Anodized Films of Aluminum Alloys" uses a three-stage sealing treatment when growing Li-Al-LDH films on aluminum alloy surfaces, where the first stage treatment temperature is 25-60℃, the second stage treatment temperature is 70-80℃, and the third stage treatment temperature is 90℃. The invention patent "A Corrosion-Resistant Thin Film of a Metal-Organic Framework Compound and Its Preparation Method" prepares a corrosion-resistant thin film with a Zn-Al-LDH inner layer and a MOF organic framework outer layer at a preparation temperature of 80-140℃. The invention patent "A Surface Pretreatment Method for Aluminum Alloys" also requires high temperatures when growing Zn-Al-LDH thin films on aluminum alloy surfaces. The invention patent "An Organic-Inorganic Composite Coating with Stable Protective Performance and Its Preparation Method" improves protective stability by constructing a silane / CeO2-modified LDH thin film on the aluminum alloy surface, but the preparation process involves constant potential cathodic deposition. The invention patent "An Aluminum Alloy Part with a Layered Double Hydroxide-Graphene Oxide Silane Composite Coating and Its Preparation Method" involves both electrodeposition and high temperatures of 40-80℃ in the preparation of the LDH-graphene oxide silane composite coating.

[0005] It is evident that growing modified LDH films on aluminum alloy surfaces to improve corrosion resistance has become a technological hotspot. However, existing technologies all require high temperatures or electrodeposition, resulting in high costs and complex processes. Furthermore, the inherent porous structure of LDH films is not conducive to resisting the intrusion of corrosive ions such as chloride ions, necessitating effective sealing treatment.

[0006] To address the aforementioned technical problems, a Chinese patent discloses a method for preparing a lithium-aluminum hydrotalcite conversion film with self-healing properties on the surface of aluminum alloys. The method involves placing the aluminum alloy in a working solution comprising lithium carbonate, lithium hydroxide, an accelerator, and additives for chemical conversion film treatment. The treatment time is 5-30 minutes, and the treatment temperature is 30°C-60°C, resulting in a lithium-aluminum hydrotalcite conversion film on the aluminum alloy surface. However, the conversion film prepared by this method has limited corrosion resistance to the aluminum alloy, and the corrosion resistance of the aluminum alloy needs further improvement. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to address the defects and deficiencies of the prior art by providing a method for obtaining a corrosion-resistant film on the surface of aluminum alloy. By immersing the aluminum alloy in an alkaline lithium carbonate solution and in a composite corrosion inhibitor solution, a corrosion-resistant film can be obtained on the surface of the aluminum alloy at room temperature and pressure, which can significantly improve the corrosion resistance of the aluminum alloy.

[0008] Another object of the present invention is to provide an aluminum alloy.

[0009] Another object of the present invention is to provide an application of aluminum alloys in aerospace, automotive or marine applications.

[0010] The above-mentioned objective of this invention is achieved through the following technical solution: A method for obtaining a corrosion-resistant film on an aluminum alloy surface includes the following steps: S1. Prepare a 0.1~1mol / L Li2CO3 aqueous solution, adjust the pH of the Li2CO3 aqueous solution to 10.5~11.5, and immerse the aluminum alloy in the Li2CO3 aqueous solution for at least 24 hours; S2. Immerse the aluminum alloy treated in step S1 in a composite corrosion inhibitor solution to obtain a corrosion-resistant film on the surface of the aluminum alloy; In step S1, the Zn content in the aluminum alloy is 5.1% to 6.1% by mass. In step S2, the composite corrosion inhibitor solution is an aqueous solution of supersaturated calcium hydroxide and a corrosion inhibitor; the corrosion inhibitor is benzotriazole and / or sodium 4-aminobenzoate; in the composite corrosion inhibitor solution, the content of supersaturated calcium hydroxide is greater than or equal to 7 g / L, the concentration of benzotriazole is greater than or equal to 0.5 mol / L, and the concentration of sodium 4-aminobenzoate is greater than or equal to 0.5 mol / L; the soaking time is at least 6 hours.

[0011] This invention enables the preparation of a LiZnAl-LDH layered bimetallic hydroxide film with certain corrosion resistance on the surface of an aluminum alloy containing Zn through step S1. This film is obtained through in-situ reaction transformation growth.

[0012] The present invention further involves immersing the sample in a composite corrosion inhibitor solution containing calcium hydroxide and a corrosion inhibitor in step S2, utilizing Ca... 2+ CO3 between LDH layers 2- The stronger adsorption capacity promotes the adsorption of benzotriazole and / or sodium 4-aminobenzoate corrosion inhibitors on LDH, while forming CaCO3 micron-sized precipitates to seal the porous LDH membrane, thereby achieving enhanced corrosion performance. This allows for the preparation of aluminum alloys with excellent corrosion resistance, specifically corrosion inhibitor@LiZnAl-LDH corrosion-resistant films.

[0013] This invention provides a method for obtaining a corrosion-resistant film on the surface of aluminum alloys. This method can achieve corrosion resistance on aluminum alloy surfaces under normal temperature and pressure, significantly improving the corrosion resistance of aluminum alloys. The method is cost-effective, simple and mild, and consumes little energy, providing favorable conditions for industrial-scale production.

[0014] In a specific implementation, the content of supersaturated calcium hydroxide can be 7~8 g / L.

[0015] In a specific implementation, the concentration of benzotriazole can be 0.5~2 mol / L.

[0016] In a specific embodiment, the concentration of sodium 4-aminobenzoate can be 0.5~2 mol / L.

[0017] Preferably, in step S1, the concentration of the lithium carbonate solution is 0.1~0.3 mol / L.

[0018] Preferably, in step S1, the pH value of the lithium carbonate solution is 11~11.5.

[0019] Preferably, in step S1, the temperature of the Li2CO3 aqueous solution is 20~30℃ and the gas pressure is atmospheric pressure.

[0020] Preferably, in step S1, the soaking time is 24 to 96 hours.

[0021] Preferably, in step S1, the aluminum alloy is 7075 aluminum alloy.

[0022] Preferably, in step S1, the aluminum alloy is a pre-treated aluminum alloy, and the pre-treatment involves sanding the surface of the aluminum alloy with sandpaper, washing, and drying.

[0023] In a specific implementation, the pretreatment can be carried out by grinding the aluminum alloy surface with 60, 240, 600, 1500, and 3000# sandpaper in sequence, washing the metal surface with deionized water, and then letting it air dry freely at room temperature.

[0024] Preferably, in step S1, the pH of the lithium carbonate solution is adjusted to 10.5-11.5 using NH4OH with a concentration of 0.5-2 mol / L.

[0025] In a specific implementation, after step S1, the aluminum alloy can be cleaned with deionized water, dried with a hair dryer using cold air, and then proceed to step S2.

[0026] Preferably, in step S2, the soaking time is 6-9 hours.

[0027] In a specific implementation, after step S2, the aluminum alloy can be cleaned with deionized water and dried with a hairdryer on a cool setting.

[0028] The present invention also protects an aluminum alloy comprising an aluminum alloy substrate and a corrosion-resistant film formed in situ on the surface of the aluminum alloy substrate, the corrosion-resistant film being prepared by a method for obtaining a corrosion-resistant film on the surface of an aluminum alloy as described in any of the preceding claims.

[0029] This invention also protects the use of the aluminum alloys described above in aerospace, automotive, or marine applications.

[0030] Compared with the prior art, the beneficial effects of the present invention are: This invention discloses a method for obtaining a corrosion-resistant film on the surface of an aluminum alloy. Step S1 involves immersing the aluminum alloy in an alkaline lithium carbonate solution to prepare a LiZnAl-LDH layered bimetallic hydroxide film with certain corrosion resistance on the surface of the Zn-containing aluminum alloy. Step S2 involves immersing the aluminum alloy in a composite corrosion inhibitor solution to prepare an aluminum alloy with excellent corrosion resistance (corrosion inhibitor@LiZnAl-LDH corrosion-resistant film).

[0031] This invention provides a method for obtaining a corrosion-resistant film on the surface of aluminum alloys. This method can achieve corrosion resistance on aluminum alloy surfaces under normal temperature and pressure, significantly improving the corrosion resistance of aluminum alloys. The method is cost-effective, simple and mild, and consumes little energy, providing favorable conditions for industrial-scale production. Attached Figure Description

[0032] Figure 1 This is a surface SEM image of the corrosion-resistant film of Example 1.

[0033] Figure 2 The AC impedance spectra of the aluminum alloys of Example 1 and Comparative Example 1 after immersion in 3.5 wt% NaCl solution for 10 days are shown.

[0034] Figure 3 The images show the corrosion morphology of the aluminum alloys of Example 1 and Comparative Example 1 after immersion in 3.5 wt% NaCl solution for 10 days. Detailed Implementation

[0035] The present invention will be further described below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise stated, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0036] 7075 aluminum alloy, 6wt% Zn, 3% Mg, 2% Cu, small amounts of Cr, Si, Mn, Fe, and the remainder Al.

[0037] Example 1 A method for obtaining a corrosion-resistant film on an aluminum alloy surface includes the following steps: Pretreatment: The surface of 7075 aluminum alloy is sanded sequentially with 60, 240, 600, 1500 and 3000# sandpaper, the metal surface is washed with deionized water and allowed to air dry at room temperature.

[0038] S1. Solution preparation: Prepare a 0.1 mol / L Li2CO3 aqueous solution and a 1 mol / L NH4OH solution. Adjust the pH of the Li2CO3 aqueous solution to 11.5 using NH4OH.

[0039] Growth of LDH film: The pretreated aluminum alloy was immersed in the above-mentioned Li2CO3 aqueous solution at 25°C and ambient pressure for 24 hours. The aluminum alloy sample was then removed, washed with deionized water, and dried with a hairdryer on a cool setting. This process yielded an aluminum alloy with a certain degree of corrosion resistance, thus forming a LiZnAl-LDH film on the surface of the aluminum alloy.

[0040] S2. Prepare a composite corrosion inhibitor solution: Prepare a 7 g / L supersaturated calcium hydroxide aqueous solution to ensure that the calcium hydroxide component in the solution remains saturated even if it is consumed by LDH, and add 0.5 mol / L benzotriazole BTA corrosion inhibitor to it.

[0041] Loading corrosion inhibitor: Immerse the aluminum alloy sample from step S2 in the above composite corrosion inhibitor solution for 6 hours. Remove the aluminum alloy sample, clean it with deionized water, and dry it with a hairdryer on a cool setting to prepare a corrosion-resistant film of @LiZnAl-LDH on the aluminum alloy surface.

[0042] Example 2 A method for obtaining a corrosion-resistant film on an aluminum alloy surface. The difference from Example 1 is as follows: S1. Solution preparation: Prepare a 0.1 mol / L Li2CO3 aqueous solution and a 1 mol / L NH4OH solution. Adjust the pH of the Li2CO3 aqueous solution to 10.5 using NH4OH.

[0043] Growth of LDH film: The pretreated aluminum alloy was immersed in the above-mentioned Li2CO3 aqueous solution at 25°C and ambient pressure for 96 hours. The aluminum alloy sample was then removed, washed with deionized water, and dried with a hairdryer on a cool setting. This process yielded an aluminum alloy with a certain degree of corrosion resistance, thus forming an aluminum alloy with a LiZnAl-LDH film on its surface.

[0044] Example 3 A method for obtaining a corrosion-resistant film on an aluminum alloy surface, which differs from Example 1 in that: S1. Solution preparation: Prepare a 1 mol / L Li2CO3 aqueous solution and a 1 mol / L NH4OH solution. Adjust the pH of the Li2CO3 aqueous solution to 10.5 using NH4OH.

[0045] Growth of LDH film: The pretreated aluminum alloy was immersed in the above-mentioned Li2CO3 aqueous solution at 25°C and ambient pressure for 24 hours. The aluminum alloy sample was then removed, washed with deionized water, and dried with a hairdryer on a cool setting. This process yielded an aluminum alloy with a certain degree of corrosion resistance, thus forming a LiZnAl-LDH film on the surface of the aluminum alloy.

[0046] Example 4 A method for obtaining a corrosion-resistant film on an aluminum alloy surface, which differs from Example 1 in that: S1. Solution preparation: Prepare a 1 mol / L Li2CO3 aqueous solution and a 1 mol / L NH4OH solution. Adjust the pH of the Li2CO3 aqueous solution to 11.5 using NH4OH.

[0047] Growth of LDH thin film: The pretreated aluminum alloy was immersed in the above-mentioned Li2CO3 aqueous solution at 25°C and ambient pressure for 60 h. The aluminum alloy sample was then removed, washed with deionized water, and dried with a hairdryer on a cool setting. This process yielded an aluminum alloy with a certain degree of corrosion resistance, thus forming an aluminum alloy with a LiZnAl-LDH thin film on its surface.

[0048] Example 5 A method for obtaining a corrosion-resistant film on an aluminum alloy surface, differing from Example 1 in that, in step S2, benzotriazole is replaced with sodium 4-aminobenzoate.

[0049] Comparative Example 1 An aluminum alloy substrate, which differs from Example 1 in that steps S1 and S2 are not performed.

[0050] Comparative Example 2 A method for obtaining a corrosion-resistant film on an aluminum alloy surface, which differs from Example 1 in that: Step S2 is not performed.

[0051] Comparative Example 3 A method for obtaining a corrosion-resistant film on an aluminum alloy surface, which differs from Example 1 in that: In step S1, a 0.01 mol / L Li2CO3 solution is prepared, and the pH of the Li2CO3 solution is adjusted to 9.5.

[0052] Comparative Example 4 A method for obtaining a corrosion-resistant film on an aluminum alloy surface, which differs from Example 1 in that: In step S1, a 0.01 mol / L Li₂CO₃ solution was prepared, and the pH of the Li₂CO₃ solution was adjusted to 10.5. The solution was then soaked at room temperature for 60 h.

[0053] Comparative Example 5 A method for obtaining a corrosion-resistant film on an aluminum alloy surface, which differs from Example 1 in that: In step S1, a 0.01 mol / L Li₂CO₃ solution was prepared, and the pH of the Li₂CO₃ solution was adjusted to 11.5. The solution was then soaked at room temperature for 96 hours.

[0054] Comparative Example 6 A method for obtaining a corrosion-resistant film on an aluminum alloy surface, which differs from Example 1 in that: In step S1, a 0.1 mol / L Li₂CO₃ solution was prepared, and the pH of the Li₂CO₃ solution was adjusted to 9.5. The solution was then soaked at room temperature for 60 hours.

[0055] Comparative Example 7 A method for obtaining a corrosion-resistant film on an aluminum alloy surface, which differs from Example 1 in that: In step S1, a 1 mol / L Li₂CO₃ solution was prepared, and the pH of the Li₂CO₃ solution was adjusted to 9.5. The solution was then soaked at room temperature for 96 hours.

[0056] Comparative Example 8 A method for obtaining a corrosion-resistant film on an aluminum alloy surface, which differs from Example 1 in that step S2 does not include supersaturated calcium hydroxide.

[0057] Comparative Example 9 A method for obtaining a corrosion-resistant film on an aluminum alloy surface, differing from Example 1 in that, in step S2, benzotriazole is replaced with sodium phosphate.

[0058] Result detection (1) The corrosion-resistant film on the surface of the aluminum alloy in Example 1 was analyzed by SEM, and the test results are as follows: Figure 1 As shown. From Figure 1 It can be seen that the corrosion-resistant film is composed of uniform micron-sized fine particles, that is, a film with uniform morphology and structure is grown on the aluminum alloy substrate.

[0059] (2) The surface composition of the corrosion-resistant film on the aluminum alloy surface of Example 1 was analyzed by EDS. The specific test results are shown in Table 1.

[0060] Table 1. EDS surface composition of the corrosion-resistant film on the aluminum alloy surface of Example 1.

[0061]

[0062] As can be seen from Table 1, divalent metal elements Zn, Mg, Cu, and Fe, as well as trivalent metal elements Al and Fe, were detected in EDS, which is consistent with the chemical composition characteristics of LDH.

[0063] (3) Low-frequency impedance modulus values ​​of aluminum alloys in each embodiment and comparative example after immersion in 3.5 wt% NaCl solution for 1 day | Z| 10mHz The test results are shown in Table 2.

[0064] Table 2 Low-frequency impedance modulus values ​​of the examples and comparative examples after soaking in 3.5 wt% NaCl solution for 1 day.

[0065]

[0066] As can be seen from Example 1 and Comparative Example 8, after adding supersaturated calcium hydroxide to the composite corrosion inhibitor solution, the low-frequency impedance modulus decreased from 43 kΩcm. 2 Increased to 90kΩcm 2 This indicates that calcium hydroxide absorbs carbonate ions from LDH to form calcium carbonate precipitate, which seals the porous structure of LDH and significantly improves the corrosion resistance of the aluminum alloy.

[0067] As can be seen from Example 1 and Comparative Example 9, the corrosion resistance of the aluminum alloy using phosphoric acid corrosion inhibitor is far inferior to that using benzotriazole corrosion inhibitor, indicating that high-valence corrosion inhibitors are difficult to load onto the LDH structure, thus resulting in insufficient corrosion resistance of the aluminum alloy.

[0068] Short-term corrosion resistance tests show that Example 1 is the optimal process.

[0069] (4) The aluminum alloys of Example 1 and Comparative Example 1, which exhibited the best performance, were immersed in a 3.5 wt% NaCl solution for 10 days, and the results were as follows: Figure 2 (a) shows the AC impedance spectrum. A common fitting circuit R(Q(R(QR))) is used for fitting. Figure 2 AC impedance spectrum as Figure 2 As shown in (b), the polarization resistance Rp of the aluminum alloy in Example 1 was 150 kΩcm. 2 The polarization resistance Rp of the aluminum alloy in Comparative Example 1 is 17 kΩcm. 2 This indicates that the BTA@LDH corrosion-resistant film improves the corrosion resistance of aluminum alloys by an order of magnitude.

[0070] (5) The surface morphology of the aluminum alloy in Example 1 after immersion in 3.5 wt% NaCl solution for 10 days is as follows: Figure 3 As shown in (a) of Comparative Example 1, the surface morphology of the aluminum alloy after immersion in 3.5 wt% NaCl solution for 10 days is as follows. Figure 3 As shown in (b) of the diagram. From Figure 3 It can be seen that Example 1, which has the best performance, has long-lasting corrosion resistance in corrosive environments.

[0071] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for obtaining a corrosion-resistant thin film on an aluminum alloy surface, characterized in that, Includes the following steps: S1. Prepare a 0.1~1mol / L Li2CO3 aqueous solution, adjust the pH of the Li2CO3 aqueous solution to 10.5~11.5, and immerse the aluminum alloy in the Li2CO3 aqueous solution for at least 24 hours; S2. Immerse the aluminum alloy treated in step S1 in a composite corrosion inhibitor solution to obtain a corrosion-resistant film on the surface of the aluminum alloy; In step S1, the Zn content in the aluminum alloy is 5.1% to 6.1% by mass. In step S2, the composite corrosion inhibitor solution is an aqueous solution of supersaturated calcium hydroxide and a corrosion inhibitor; the corrosion inhibitor is benzotriazole and / or sodium 4-aminobenzoate; in the composite corrosion inhibitor solution, the content of supersaturated calcium hydroxide is greater than or equal to 7 g / L, the concentration of benzotriazole is greater than or equal to 0.5 mol / L, and the concentration of sodium 4-aminobenzoate is greater than or equal to 0.5 mol / L; the soaking time is at least 6 hours.

2. The method for obtaining a corrosion-resistant film on an aluminum alloy surface as described in claim 1, characterized in that, In step S1, the concentration of the lithium carbonate solution is 0.1~0.3 mol / L.

3. The method for obtaining a corrosion-resistant film on an aluminum alloy surface as described in claim 1, characterized in that, In step S1, the pH value of the lithium carbonate solution is 11~11.

5.

4. The method for obtaining a corrosion-resistant film on an aluminum alloy surface as described in claim 1, characterized in that, In step S1, the temperature of the Li2CO3 aqueous solution is 20~30℃, the gas pressure is atmospheric pressure, and the soaking time is 24~96h.

5. The method for obtaining a corrosion-resistant film on an aluminum alloy surface as described in claim 1, characterized in that, In step S1, the aluminum alloy is 7075 aluminum alloy.

6. The method for obtaining a corrosion-resistant film on an aluminum alloy surface as described in claim 1, characterized in that, In step S1, the aluminum alloy is a pre-treated aluminum alloy, which involves sanding the surface of the aluminum alloy with sandpaper, washing, and drying.

7. The method for obtaining a corrosion-resistant film on an aluminum alloy surface as described in claim 1, characterized in that, In step S1, the pH of the lithium carbonate solution is adjusted to 10.5-11.5 using NH4OH with a concentration of 0.5-2 mol / L.

8. The method for obtaining a corrosion-resistant film on an aluminum alloy surface as described in claim 1, characterized in that, In step S2, the soaking time is 6 to 9 hours.

9. An aluminum alloy, characterized in that, It includes an aluminum alloy substrate and a corrosion-resistant film formed in situ on the surface of the aluminum alloy substrate, wherein the corrosion-resistant film is prepared by the method for obtaining a corrosion-resistant film on the surface of an aluminum alloy as described in any one of claims 1 to 8.

10. The application of the aluminum alloy of claim 9 in aerospace, automotive or marine applications.

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