Preparation method of passivator for high-rust-resistance aluminum alloy

Abstract

The invention discloses a preparation method of a passivator for a high-rust-prevention aluminum alloy, and belongs to the technical field of rust-prevention materials.The passivator comprises a self-repairing nanocapsule, an environment-friendly corrosion inhibitor, a functional silane coupling agent, inorganic anti-corrosion pigment and an assistant.The self-repairing nanocapsule can form a passivation film with a self-repairing function on the surface of the aluminum alloy, and the passivation film can be applied to the surface of the aluminum alloy; the environment-friendly corrosion inhibitor provides anti-rust performance and biocompatibility, the functional silane coupling agent enhances the adhesive force and weather resistance of a passivation film, the inorganic anti-corrosion pigment serves as a main component of the passivation film to provide excellent anti-corrosion performance, and the passivation agent is applied to the surface of an aluminum alloy in a dipping, spraying, brushing or electrochemical deposition mode. According to the passivating agent, the self-repairing nanocapsule is added to form a layer of passivating film with a self-repairing function and excellent anti-rust performance, the anti-rust performance and durability of the aluminum alloy are remarkably improved through the passivating agent, and the performance is gradually enhanced along with increase of the content of the self-repairing nanocapsule.

Description

Technical Field

[0001] The invention relates to the technical field of rust-proof materials, and more specifically to a method for preparing a passivating agent for high rust-proof aluminum alloy. Background Art

[0002] As a lightweight, high-strength metal material, aluminum alloy is widely used in aerospace, automobile manufacturing, construction and other fields. However, aluminum alloy is prone to rust in humid and corrosive environments, which seriously affects its service life and safety. Therefore, the development of an efficient and environmentally friendly anti-rust treatment technology is of great significance for the application of aluminum alloy.

[0003] Traditional aluminum alloy anti-rust treatment methods mainly include anodizing, chemical conversion film, organic coating, etc. Anodizing technology improves the corrosion resistance of aluminum alloy by forming a dense aluminum oxide film on the surface of aluminum alloy, but this method has high energy consumption, complex process, and the generated film is brittle and easy to crack. Chemical conversion film technology forms a layer of inorganic compound film on the surface of aluminum alloy through chemical reaction. Although the process is simple, the corrosion resistance of the film is limited, and environmental protection issues are becoming increasingly prominent. Organic coating technology is to apply a layer of organic coating on the surface of aluminum alloy. Although it can provide certain anti-rust performance, the coating is prone to aging and falling off, and the pollution to the environment cannot be ignored.

[0004] Therefore, in view of the above content, the present invention proposes a method for preparing a passivating agent for high rust-proof aluminum alloy to solve the above problems. Summary of the invention

[0005] 1. Technical issues to be solved

[0006] In view of the problems existing in the prior art, the purpose of the present invention is to provide a method for preparing a passivator for highly rust-proof aluminum alloys, which can realize that by introducing self-repairing nanocapsules, the passivator can form a passivation film with self-repairing function on the surface of the aluminum alloy, which can not only effectively block the invasion of external corrosive media (such as water, oxygen, salt spray, etc.), but also can automatically repair the damaged parts through the self-repairing agent in the self-repairing nanocapsules when minor damage occurs, thereby greatly extending the service life of the aluminum alloy. With the increase of the content of self-repairing nanocapsules, the rust and corrosion resistance are further enhanced. Compared with the prior art, the passivator of the present invention not only has a significantly improved anti-rust effect when used, but also the adhesion between the passivation film and the aluminum alloy substrate is further improved, and the anti-rust life is longer.

[0007] 2. Technical solution

[0008] To solve the above problems, the present invention adopts the following technical solutions.

[0009] A method for preparing a passivator for high rust-proof aluminum alloy, the passivator comprising the following components in weight percentage:

[0010] Self-repairing nanocapsules: 5-20%, wherein the nanocapsules contain a self-repairing agent, and the outer wall is composed of a degradable polymer, which can form a passivation film with self-repairing function on the surface of the aluminum alloy;

[0011] Environmentally friendly corrosion inhibitors: 3-15%, selected from natural plant extracts or microbial metabolites, used to provide rust prevention and biocompatibility;

[0012] Functional silane coupling agent: 5-20%, used to enhance the adhesion and weather resistance of the passivation film;

[0013] Inorganic anticorrosive pigments: 10-30%, as the main component of the passivation film, providing excellent anticorrosion performance;

[0014] Additives: balance.

[0015] As a further improvement of the present invention, the preparation method of the passivating agent comprises the following steps:

[0016] a. Preparation of self-repairing nanocapsules;

[0017] b. Evenly mix the environmentally friendly corrosion inhibitor, functional silane coupling agent, inorganic anticorrosive pigment, and additives to form a basic passivation solution;

[0018] c. adding the self-repairing nanocapsules obtained in step a to the basic passivation solution, and uniformly dispersing them by mechanical stirring or ultrasonic treatment;

[0019] d. Adjust the pH value of the mixture to 7-9, and then filter the prepared passivating agent to remove possible impurities and unevenly dispersed nanocapsules. The filtration can be performed using a microporous filter membrane, an ultrafiltration membrane, or a nanofiltration membrane.

[0020] As a further improvement of the present invention, the method for preparing the self-repairing nanocapsules comprises the following steps:

[0021] S1, dissolving the self-healing agent in an appropriate amount of solvent to form a self-healing agent solution;

[0022] S2, dissolving or dispersing the outer wall material in another solvent to form an outer wall material solution;

[0023] S3, adding the self-healing agent solution dropwise to the outer wall material solution, preparing nanocapsules by microemulsion method, self-assembly method or spray drying method. During the preparation process, an appropriate amount of catalyst can be added to promote the curing or cross-linking of the self-healing agent in the nanocapsules;

[0024] S4. Washing, drying and sieving the prepared nanocapsules to obtain self-repairing nanocapsules with uniform size and good dispersion.

[0025] As a further improvement of the present invention, the self-healing agent is one of epoxy resin, polyurethane or polyurea, and its content is 30%-50% of the total mass; the outer wall material is one of polylactic acid, starch or cellulose, and its content is 10%-30% of the total mass; the remaining solvent is ethanol or acetone; the catalyst is dibutyltin dilaurate, and its added amount is 1%-5% of the mass of the self-healing agent.

[0026] Polymer materials such as epoxy resin, polyurethane or polyurea are selected as self-healing agents. These materials can respond quickly and repair cracks when damaged, thereby restoring the integrity of the material. Degradable polymers such as polylactic acid (PLA), starch or cellulose are used as the outer wall of the nanocapsule. These materials can degrade under specific conditions and release the internal self-healing agent. Nanocapsules are prepared by microemulsion method, self-assembly method or spray drying method to ensure that the nanocapsules are uniform in size, have good dispersion and high encapsulation efficiency. During the preparation process, an appropriate amount of catalyst can be added to promote the curing or cross-linking of the self-healing agent in the nanocapsule and improve the self-healing performance.

[0027] As a further improvement of the present invention, in step S2, a sharp nano material is added whose mass accounts for 1%-3% of the outer wall material, and the nano material is nano silicon dioxide or nano aluminum oxide and is prepared by a template method.

[0028] As a further improvement of the present invention, the environmentally friendly corrosion inhibitor is one of tea polyphenols, curcumin, chitosan, and lactic acid bacteria metabolites.

[0029] These substances have excellent anti-rust properties and biocompatibility. Through specific extraction, purification or modification processes, the solubility and stability of green corrosion inhibitors in passivators are improved while maintaining their natural anti-rust activity. For example, extraction methods such as water distillation, solvent extraction or ultrasonic extraction, as well as purification methods such as recrystallization, column chromatography or membrane separation can be used.

[0030] As a further improvement of the present invention, the functional silane coupling agent is one of vinyl trimethoxy silane, γ-glycidyloxypropyl trimethoxy silane or γ-aminopropyl triethoxy silane, one end of the functional silane coupling agent can form a chemical bond with the surface of the aluminum alloy, and the other end can form a cross-linked structure with other components in the passivation film (such as inorganic anticorrosive pigments), thereby improving the density and corrosion resistance of the passivation film.

[0031] As a further improvement of the present invention, the inorganic anti-corrosion pigment is one of zinc phosphate, aluminum silicate or zirconate. The inorganic anti-corrosion pigment can form a dense passivation film with the surface of the aluminum alloy to prevent corrosion by harmful substances such as oxygen, moisture and corrosive ions. At the same time, the inorganic anti-corrosion pigment can also form a cross-linked structure with a functional silane coupling agent to further improve the corrosion resistance of the passivation film.

[0032] As a further improvement of the present invention, the auxiliary agent is a mixture of deionized water and a pH regulator.

[0033] The passivating agent is used in the surface treatment of aluminum alloys. The passivating agent is applied to the surface of the aluminum alloy by dipping, spraying, brushing or electrochemical deposition, and then dried and cured at room temperature to 200° C. to form a passivation film with self-repairing function and excellent anti-rust performance. The drying and curing process is carried out in a nitrogen atmosphere.

[0034] 3. Beneficial effects

[0035] Compared with the prior art, the advantages of the present invention are:

[0036] (1) This scheme introduces self-repairing nanocapsules. The passivating agent can form a passivation film with self-repairing function on the surface of aluminum alloy. This film can not only effectively block the invasion of external corrosive media (such as water, oxygen, salt spray, etc.), but also automatically repair the damaged parts through the self-repairing agent in the self-repairing nanocapsules when minor damage occurs, thereby greatly extending the service life of the aluminum alloy. With the increase of the content of self-repairing nanocapsules, the anti-rust and corrosion resistance are further enhanced.

[0037] (2) The addition of the functional silane coupling agent in this scheme significantly improves the adhesion between the passivation film and the aluminum alloy substrate, making the passivation film more firmly attached to the aluminum alloy surface and not easy to fall off. At the same time, the functional silane coupling agent can also improve the weather resistance of the passivation film, so that it can still maintain good performance in various harsh environments (such as high temperature, low temperature, humidity, etc.), further extending the service life of the aluminum alloy.

[0038] (3) The present invention not only further improves the rust resistance and corrosion resistance of the passivation film by adding sharp nano-silica to the outer wall material of the self-repairing nanocapsule, but also significantly enhances its self-repairing ability. The addition of sharp nano-silica enables the passivation film to identify and repair damaged parts more quickly when damaged, thereby improving the overall performance and stability of the passivation film. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a flow chart of the preparation method of the present invention;

[0040] Figure 2 This is a data table of performance tests of Examples 1-4 of the present invention. DETAILED DESCRIPTION

[0041] Four implementation modes of the present application are described in detail below with reference to the accompanying drawings.

[0042] The first implementation method:

[0043] A method for preparing a passivator for high rust-proof aluminum alloy, the passivator comprising the following components in weight percentage:

[0044] Self-repairing nanocapsules: 5%, wherein the nanocapsules contain a self-repairing agent, and the outer wall is composed of a degradable polymer, which can form a passivation film with self-repairing function on the surface of the aluminum alloy;

[0045] Environmentally friendly corrosion inhibitor: 3%, selected from natural plant extracts or microbial metabolites, used to provide rust prevention and biocompatibility;

[0046] Functional silane coupling agent: 5%, used to enhance the adhesion and weather resistance of the passivation film;

[0047] Inorganic anti-corrosion pigment: 10%, as the main component of the passivation film, providing excellent anti-corrosion performance;

[0048] Additives: balance.

[0049] The preparation method of the passivator comprises the following steps:

[0050] a. Preparation of self-repairing nanocapsules;

[0051] b. Evenly mix the environmentally friendly corrosion inhibitor, functional silane coupling agent, inorganic anticorrosive pigment, and additives to form a basic passivation solution;

[0052] c. adding the self-repairing nanocapsules obtained in step a to the basic passivation solution, and uniformly dispersing them by mechanical stirring or ultrasonic treatment;

[0053] d. Adjust the pH value of the mixture to 8, and then filter the prepared passivating agent to remove possible impurities and nanocapsules that are not evenly dispersed. The filtration can be performed using a microporous filter membrane, an ultrafiltration membrane, or a nanofiltration membrane.

[0054] The preparation method of the self-repairing nanocapsule comprises the following steps:

[0055] S1, dissolving the self-healing agent in an appropriate amount of solvent to form a self-healing agent solution;

[0056] S2, dissolving or dispersing the outer wall material in another solvent to form an outer wall material solution;

[0057] S3, adding the self-healing agent solution dropwise to the outer wall material solution, preparing nanocapsules by microemulsion method, self-assembly method or spray drying method. During the preparation process, an appropriate amount of catalyst can be added to promote the curing or cross-linking of the self-healing agent in the nanocapsules;

[0058] S4. Washing, drying and sieving the prepared nanocapsules to obtain self-repairing nanocapsules with uniform size and good dispersion.

[0059] The self-healing agent is epoxy resin, which accounts for 30% of the total mass; the outer wall material is polylactic acid, which accounts for 10% of the total mass; the remaining solvent is ethanol; and the catalyst is dibutyltin dilaurate, which is added in an amount of 1% of the mass of the self-healing agent.

[0060] The environmentally friendly corrosion inhibitor is tea polyphenols.

[0061] The functional silane coupling agent is vinyltrimethoxysilane.

[0062] The inorganic anticorrosive pigment is zinc phosphate.

[0063] The passivating agent is applied to the surface of the aluminum alloy by dipping, spraying, brushing or electrochemical deposition, and then dried and cured at room temperature to 200° C. to form a passivation film with self-repairing function and excellent anti-rust performance. The drying and curing process is carried out in a nitrogen atmosphere.

[0064] Second implementation method:

[0065] A method for preparing a passivator for high rust-proof aluminum alloy, the passivator comprising the following components in weight percentage:

[0066] Self-repairing nanocapsules: 15%, wherein the nanocapsules contain a self-repairing agent, and the outer wall is composed of a degradable polymer, which can form a passivation film with self-repairing function on the surface of the aluminum alloy;

[0067] Environmentally friendly corrosion inhibitor: 10%, selected from natural plant extracts or microbial metabolites, used to provide rust prevention and biocompatibility;

[0068] Functional silane coupling agent: 15%, used to enhance the adhesion and weather resistance of the passivation film;

[0069] Inorganic anti-corrosion pigment: 20%, as the main component of the passivation film, providing excellent anti-corrosion performance;

[0070] Additives: balance.

[0071] The preparation method of the passivator comprises the following steps:

[0072] a. Preparation of self-repairing nanocapsules;

[0073] b. Evenly mix the environmentally friendly corrosion inhibitor, functional silane coupling agent, inorganic anticorrosive pigment, and additives to form a basic passivation solution;

[0074] c. adding the self-repairing nanocapsules obtained in step a to the basic passivation solution, and uniformly dispersing them by mechanical stirring or ultrasonic treatment;

[0075] d. Adjust the pH value of the mixture to 8, and then filter the prepared passivating agent to remove possible impurities and unevenly dispersed nanocapsules. The filtration can be performed using a microporous filter membrane, an ultrafiltration membrane, or a nanofiltration membrane.

[0076] The preparation method of the self-repairing nanocapsule comprises the following steps:

[0077] S1, dissolving the self-healing agent in an appropriate amount of solvent to form a self-healing agent solution;

[0078] S2, dissolving or dispersing the outer wall material in another solvent to form an outer wall material solution;

[0079] S3, adding the self-healing agent solution dropwise to the outer wall material solution, preparing nanocapsules by microemulsion method, self-assembly method or spray drying method. During the preparation process, an appropriate amount of catalyst can be added to promote the curing or cross-linking of the self-healing agent in the nanocapsules;

[0080] S4. Washing, drying and sieving the prepared nanocapsules to obtain self-repairing nanocapsules with uniform size and good dispersion.

[0081] The self-healing agent is epoxy resin, which accounts for 40% of the total mass. The outer wall material is polylactic acid, which accounts for 20% of the total mass. The remaining solvent is ethanol. The catalyst is dibutyltin dilaurate, and the added amount is 3% of the mass of the self-healing agent.

[0082] The environmentally friendly corrosion inhibitor is tea polyphenols.

[0083] The functional silane coupling agent is vinyltrimethoxysilane.

[0084] The inorganic anticorrosive pigment is zinc phosphate.

[0085] The passivating agent is applied to the surface of the aluminum alloy by dipping, spraying, brushing or electrochemical deposition, and then dried and cured at room temperature to 200° C. to form a passivation film with self-repairing function and excellent anti-rust performance. The drying and curing process is carried out in a nitrogen atmosphere.

[0086] The third implementation method:

[0087] A method for preparing a passivator for high rust-proof aluminum alloy, the passivator comprising the following components in weight percentage:

[0088] Self-repairing nanocapsules: 20%, wherein the nanocapsules contain a self-repairing agent, and the outer wall is composed of a degradable polymer, which can form a passivation film with self-repairing function on the surface of the aluminum alloy;

[0089] Environmentally friendly corrosion inhibitor: 15%, selected from natural plant extracts or microbial metabolites, used to provide rust prevention and biocompatibility;

[0090] Functional silane coupling agent: 20%, used to enhance the adhesion and weather resistance of the passivation film;

[0091] Inorganic anti-corrosion pigment: 30%, as the main component of the passivation film, providing excellent anti-corrosion performance;

[0092] Additives: balance.

[0093] The preparation method of the passivator comprises the following steps:

[0094] a. Preparation of self-repairing nanocapsules;

[0095] b. Evenly mix the environmentally friendly corrosion inhibitor, functional silane coupling agent, inorganic anticorrosive pigment, and additives to form a basic passivation solution;

[0096] c. adding the self-repairing nanocapsules obtained in step a to the basic passivation solution, and uniformly dispersing them by mechanical stirring or ultrasonic treatment;

[0097] d. Adjust the pH value of the mixture to 8, and then filter the prepared passivating agent to remove possible impurities and unevenly dispersed nanocapsules. The filtration can be performed using a microporous filter membrane, an ultrafiltration membrane, or a nanofiltration membrane.

[0098] The preparation method of the self-repairing nanocapsule comprises the following steps:

[0099] S1, dissolving the self-healing agent in an appropriate amount of solvent to form a self-healing agent solution;

[0100] S2, dissolving or dispersing the outer wall material in another solvent to form an outer wall material solution;

[0101] S3, adding the self-healing agent solution dropwise to the outer wall material solution, preparing nanocapsules by microemulsion method, self-assembly method or spray drying method. During the preparation process, an appropriate amount of catalyst can be added to promote the curing or cross-linking of the self-healing agent in the nanocapsules;

[0102] S4. Washing, drying and sieving the prepared nanocapsules to obtain self-repairing nanocapsules with uniform size and good dispersion.

[0103] The self-healing agent is epoxy resin, which accounts for 50% of the total mass. The outer wall material is polylactic acid, which accounts for 30% of the total mass. The remaining solvent is ethanol. The catalyst is dibutyltin dilaurate, and the added amount is 5% of the mass of the self-healing agent.

[0104] The environmentally friendly corrosion inhibitor is tea polyphenols.

[0105] The functional silane coupling agent is vinyltrimethoxysilane.

[0106] The inorganic anticorrosive pigment is zinc phosphate.

[0107] The passivating agent is applied to the surface of the aluminum alloy by dipping, spraying, brushing or electrochemical deposition, and then dried and cured at room temperature to 200° C. to form a passivation film with self-repairing function and excellent anti-rust performance. The drying and curing process is carried out in a nitrogen atmosphere.

[0108] The fourth implementation method:

[0109] On the basis of Example 3, in step S2, a sharp nano material accounting for 3% of the mass of the outer wall material is added, and the nano material is nano silicon dioxide and is prepared by a template method.

[0110] Performance tests were performed on Examples 1-4, specifically on the aluminum alloy samples after drying and curing, including salt spray test, electrochemical corrosion test, scratch test, etc. to evaluate the anti-rust performance and durability of the passivation film.

[0111] Salt spray test:

[0112] It can be seen from the data that with the increase of the content of self-repairing nanocapsules, the time of the salt spray test gradually prolonged, indicating that the anti-rust performance of the passivation film gradually enhanced.

[0113] After adding the sharp nano-silicon dioxide, the salt spray test time of Example 4 reached 1200 hours, which is the best performance among all the examples, indicating that the addition of the sharp nano-material significantly improves the anti-rust performance of the passivation film.

[0114] Electrochemical corrosion test:

[0115] The corrosion rate is an important indicator to measure the corrosion resistance of materials. From the data, it can be seen that with the increase of the content of self-repairing nanocapsules, the corrosion rate gradually decreases, indicating that the corrosion resistance of the passivation film is gradually enhanced.

[0116] The corrosion rate of Example 4 is the lowest, which is only 0.01 mpy, indicating that the addition of sharp nano-silicon dioxide further improves the corrosion resistance of the passivation film.

[0117] Scratch test:

[0118] The scratch test is used to evaluate the self-healing ability of the passivation film. From the data, it can be seen that with the increase of the content of self-healing nanocapsules, the repair rate gradually increases.

[0119] The repair rate of Example 4 was the highest, reaching 98%, indicating that the addition of sharp nano-silicon dioxide not only improved the rust resistance and corrosion resistance of the passivation film, but also significantly enhanced its self-repairing ability.

[0120] In summary, by comparing the performance test data of the four embodiments, the following conclusions can be drawn:

[0121] The addition of self-healing nanocapsules significantly improved the anti-rust and corrosion resistance of the passivation film, and the performance gradually increased with the increase of content.

[0122] The addition of sharp nano-silica further improves the rust resistance, corrosion resistance and self-repairing ability of the passivation film, and is an effective means to improve the performance of the passivation film.

[0123] The above is only a preferred specific implementation of the present invention; however, the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solution and its improved conception within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing a passivating agent for high rust-proof aluminum alloy, characterized in that: The passivator comprises the following components in weight percentage: Self-repairing nanocapsules: 5-20%, wherein the nanocapsules contain a self-repairing agent, and the outer wall is composed of a degradable polymer, which can form a passivation film with self-repairing function on the surface of the aluminum alloy; Environmentally friendly corrosion inhibitors: 3-15%, selected from natural plant extracts or microbial metabolites, used to provide rust prevention and biocompatibility; Functional silane coupling agent: 5-20%, used to enhance the adhesion and weather resistance of the passivation film; Inorganic anticorrosive pigments: 10-30%, as the main component of the passivation film, providing excellent anticorrosion performance; Additives: balance.

2. The method for preparing a passivating agent for high rust-proof aluminum alloy according to claim 1, characterized in that: The preparation method of the passivator comprises the following steps: a. Preparation of self-repairing nanocapsules; b. Evenly mix the environmentally friendly corrosion inhibitor, functional silane coupling agent, inorganic anticorrosive pigment, and additives to form a basic passivation solution; c. adding the self-repairing nanocapsules obtained in step a to the basic passivation solution, and uniformly dispersing them by mechanical stirring or ultrasonic treatment; d. Adjust the pH value of the mixture to 7-9, and then filter the prepared passivating agent to remove possible impurities and unevenly dispersed nanocapsules. The filtration can be performed using a microporous filter membrane, an ultrafiltration membrane, or a nanofiltration membrane.

3. The method for preparing a passivating agent for high rust-proof aluminum alloy according to claim 2, characterized in that: The preparation method of the self-repairing nanocapsule comprises the following steps: S1, dissolving the self-healing agent in an appropriate amount of solvent to form a self-healing agent solution; S2, dissolving or dispersing the outer wall material in another solvent to form an outer wall material solution; S3, adding the self-healing agent solution dropwise to the outer wall material solution, preparing nanocapsules by microemulsion method, self-assembly method or spray drying method. During the preparation process, an appropriate amount of catalyst can be added to promote the curing or cross-linking of the self-healing agent in the nanocapsules; S4. Washing, drying and sieving the prepared nanocapsules to obtain self-repairing nanocapsules with uniform size and good dispersion.

4. The method for preparing a passivating agent for high rust-proof aluminum alloy according to claim 3, characterized in that: The self-healing agent is one of epoxy resin, polyurethane or polyurea, and its content is 30%-50% of the total mass. The outer wall material is one of polylactic acid, starch or cellulose, and its content is 10%-30% of the total mass. The remaining solvent is ethanol or acetone. The catalyst is dibutyltin dilaurate, and its added amount is 1%-5% of the mass of the self-healing agent.

5. The method for preparing a passivating agent for high rust-proof aluminum alloy according to claim 4, characterized in that: In the step S2, a sharp nano material is added, the mass of which accounts for 1% to 3% of the outer wall material. The nano material is nano silicon dioxide or nano aluminum oxide and is prepared by a template method.

6. The method for preparing a passivating agent for high rust-proof aluminum alloy according to claim 1, characterized in that: The environmentally friendly corrosion inhibitor is one of tea polyphenols, curcumin, chitosan and lactic acid bacteria metabolites.

7. The method for preparing a passivating agent for high rust-proof aluminum alloy according to claim 1, characterized in that: The functional silane coupling agent is one of vinyl trimethoxy silane, γ-glycidyloxypropyl trimethoxy silane or γ-aminopropyl triethoxy silane.

8. The method for preparing a passivating agent for high rust-proof aluminum alloy according to claim 1, characterized in that: The inorganic anticorrosive pigment is one of zinc phosphate, aluminum silicate or zirconate.

9. The method for preparing a passivating agent for high rust-proof aluminum alloy according to claim 8, characterized in that: The auxiliary agent is a mixture of deionized water and a pH regulator.

10. Use of the passivating agent according to any one of claims 1 to 9 in the surface treatment of aluminum alloys, characterized in that: The passivating agent is applied to the surface of the aluminum alloy by dipping, spraying, brushing or electrochemical deposition, and then dried and cured at room temperature to 200° C. to form a passivation film with self-repairing function and excellent anti-rust performance. The drying and curing process is carried out in a nitrogen atmosphere.

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