Method for preparing corrosion-resistant MXene-based nano composite coating on aluminum and aluminum alloy

Abstract

The invention discloses a method for preparing a corrosion-resistant MXene-based nano-composite coating on aluminum and an alloy thereof. The method comprises the following steps: carrying out pretreatment such as polishing, oil removal, acid pickling and activation on a metal matrix; preparing a GMZB nano-filler, coating the GMZB nano-filler and resin on the surface of a metal matrix, and curing to form a uniform and compact nano-composite coating; and finally, cleaning, drying and other post-plating treatment are conducted. The prepared MXene-based nano-composite coating is compact and smooth in surface, defects and cracks generated in the curing process of a traditional organic coating are greatly reduced, compared with a contrast, the self-corrosion potential is improved, the self-corrosion current density and the corrosion rate are reduced, the self-healing efficiency is improved, good physical barrier, chemical passivation and dynamic self-repairing functions are shown, and the application prospect is wide. And the service life of aluminum and aluminum alloy can be effectively prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal surface coatings, and more specifically, the present invention relates to a method for preparing a corrosion-resistant MXene-based nanocomposite coating on aluminum and its alloys. Background Art

[0002] Aluminum alloys are widely used in aerospace, marine engineering, transportation and other fields due to their light weight, high strength and machinability. However, they are susceptible to Cl in marine environments. - Corrosion by corrosive media such as H2O and O2 leads to oxide film destruction and localized corrosion. Although traditional organic coatings such as epoxy resin coatings are chemically stable, they have problems such as high brittleness, many curing defects, and insufficient long-term protection.

[0003] In recent years, two-dimensional materials such as MXene and graphene oxide (GO) have been used to enhance coating performance due to their high surface area, barrier properties, and chemical activity. However, MXene is prone to oxidation and stacking, while GO is prone to agglomeration, making the passive protection provided by a single material difficult to meet long-term requirements. Furthermore, the direct addition of corrosion inhibitors (such as BTA) can easily lose effectiveness due to rapid release and lack intelligent responsiveness.

[0004] Metal-organic frameworks (MOFs), such as ZIF-8, can be used as corrosion inhibitor carriers for controlled release due to their porous structure and pH-responsive properties. While there have been reports combining MOFs with two-dimensional materials, the synergistic effects of GO / MXene multilayer heterostructures have not been fully exploited, and in-depth research into dynamic self-healing mechanisms is lacking. Therefore, the development of multifunctional composite coatings that combine physical barrier properties, chemical adsorption, and intelligent controlled release is of great significance. Summary of the Invention

[0005] An object of the present invention is to solve at least the above problems and / or disadvantages and to provide at least the advantages which will be described hereinafter.

[0006] To achieve these objects and other advantages of the present invention, a method for preparing a corrosion-resistant MXene-based nanocomposite coating on aluminum and its alloys is provided, comprising the following steps: S1. Metal substrate pretreatment: The metal substrate is polished, degreased with organic solvents, degreased at high temperature, electrolytically degreased and oxide film removed, pickled, and activated in sequence; S2. Preparation of nanocomposite coating: preparing nanofillers, dispersing the prepared nanofillers in ethanol, ultrasonically treating and mixing with epoxy resin, vacuum degassing, adding a curing agent and mixing to obtain a mixed solution, applying the mixed solution to the pre-treated metal substrate surface, and curing at room temperature for 24 hours to form a uniform and dense nanocomposite coating; S3. Post-plating treatment: Rinse the coated parts with clean water and then dry them.

[0007] Preferably, in S1, the metal substrate is an aluminum plate or an aluminum alloy plate.

[0008] Preferably, the S1 specifically includes: S1.1. Grinding: Use 400-2000 mesh SiC sandpaper to polish the metal substrate, and rinse with deionized water after grinding; S1.2, Organic solvent degreasing: Place the cleaned aluminum plate in an acetone organic solution and degrease it at an ultrasonic frequency of 20-40 kHz for 15-20 minutes, then rinse with deionized water; S1.3, High-temperature degreasing: Place the metal substrate after degreasing with an organic solvent in a high-temperature degreasing solution and degrease at a temperature of 60-90°C for 5-10 minutes. After degreasing, rinse it in deionized water at 70-90°C. The composition and concentration of the degreasing solution are: 45g / L sodium carbonate, 45g / L sodium phosphate, and 15g / L sodium silicate. S1.4. Electrolytic degreasing and oxide film removal: Place the metal substrate as an electrode in the electrolyte and perform electrolysis at a voltage of 8-15V and a temperature of 25-35°C for 3-5 minutes. After the electrolysis is completed, rinse it in deionized water at 70-90°C. The composition and concentration of the electrolyte for electrolytic degreasing and oxide film removal are: 25g / L sodium carbonate, 25g / L sodium phosphate, and 4g / L sodium silicate. S1.5, pickling: put the metal substrate after electrolytic degreasing and oxide film removal into 30% nitric acid for pickling for 1-3 minutes. After pickling, rinse thoroughly with deionized water. S1.6, Activation: Place the pickled aluminum plate in a 30g / L boric acid solution for activation for 2-6 minutes. After activation, rinse with deionized water and dry for later use. Preferably, in S2, the method for preparing the nanofiller is specifically: S2.1. Preparation of multilayer Ti3C2TxMXene nanosheets: Slowly add MAX phase Ti3AlC2 to a HCl solution containing LiF, heat in an oil bath and stir. After the reaction is complete, wash the reaction product with deionized water several times to remove impurities and residual acid until the pH of the supernatant reaches about 7, and then freeze-dry to obtain multilayer Ti3C2TxMXene nanosheets.

[0009] S2.2 Preparation of graphene oxide (GO): Graphene flakes and NaNO3 were stirred in an H2SO4 solution on an ice bath. KMnO4 was then added and heated with stirring. Unreacted particles were then removed by adding deionized water and H2O2. The GO was then washed several times with HCl and deionized water until neutral, and finally freeze-dried to obtain GO. S2.3, slowly adding the GO aqueous dispersion to the multilayer Ti3C2TxMXene aqueous dispersion, stirring after ultrasonic treatment, and then washing and freeze-drying to obtain covalently bonded GO-Ti3C2TxMXene, i.e., GM nanofiller; S2.4. Dispersing the GM nanofiller in methanol. Separately, zinc nitrate and 2-methylimidazole were added to methanol, stirred at room temperature until dissolved to obtain two transparent solutions. The two solutions were then added to the methanol containing the GM nanofiller for solvothermal synthesis. The synthesized product was washed with methanol and dried in vacuo to obtain GO-Ti3C2TxMXene / ZIF-8, i.e., GMZ nanofiller. S2.5. Disperse the GMZ nanofiller in deionized water, disperse the corrosion inhibitor benzotriazole (BTA) in methanol, then add the BTA dispersion dropwise to the GMZ dispersion, stir under vacuum at room temperature, centrifuge and wash the stirred suspension with methanol several times and vacuum dry to obtain the GO-Ti3C2TxMXene / ZIF-8@BTA nanocomposite material, namely, GMZB nanofiller.

[0010] Preferably, in S2.1, the amount ratio of Ti3AlC2 and the HCl solution containing LiF is 1~2g:20~30mL, the concentration of the HCl solution is 9M, the amount ratio of LiF and HCl is 15~25g:20~30mL, the oil bath heating temperature is 35~40°C, stirring is performed for 24~32h, the freeze-drying temperature is -60~-80°C, and freeze-drying is performed for 20~24h.

[0011] Preferably, in S2.2, the amount ratio of graphite flakes, NaNO3, H2SO4 solution, and KMnO4 is 1~2g:0.5~1g:20~30mL:3~6g, the concentration of H2SO4 solution is 18~20M, the mixture is stirred in an ice bath for 15~20min, and after adding KMnO4, the mixture is stirred at 35~40°C for 2~4h. The volume ratio of the added amount of deionized water and H2O2 to the H2SO4 solution is 1~2:1~2:1, the freeze-drying temperature is -60~-80°C, and the freeze-drying is performed for 20~24h.

[0012] In S2.3, the concentrations of the GO aqueous dispersion and the multilayer Ti3C2TxMXene aqueous dispersion are both 1~10 mg / mL, and GO and multilayer Ti3C2TxMXene are added in a mass ratio of 1:1. The ultrasonic treatment frequency is 40~60 kHz, and the ultrasonic treatment is 15~30 min. Then, the mixture is stirred at room temperature for 6~8 h, and then the centrifuged mixture is washed with deionized water several times, and finally freeze-dried at -60~-80°C for 20~24 h.

[0013] Preferably, it is characterized in that, in S2.4, the amount ratio of GM nanofiller and methanol is 0.1~0.2g:10~30mL, the amount ratio of zinc nitrate and methanol is 0.1~0.5g:10~30mL, the amount ratio of 2-methylimidazole and methanol is 0.5~1g:10~30mL, the mass ratio of GM nanofiller, zinc nitrate and 2-methylimidazole is 1~2:1~5:5~10, the heating temperature during solvent thermal synthesis is 90~100°C, heating for 20~30h, vacuum drying temperature is 60~70°C, and drying is carried out for 18~24h.

[0014] Preferably, in S2.5, the dosage ratio of GMZ nanofiller and deionized water is 0.15~0.20g:10~20mL, the dosage ratio of corrosion inhibitor benzotriazole and methanol is 0.075~0.150g:10~20mL, the mass ratio of GMZ nanofiller and corrosion inhibitor benzotriazole is 2~3:1~2, vacuum stirring is performed for 5h, the vacuum drying temperature is 40~60°C, and vacuum drying is performed for 18~24h.

[0015] Preferably, in S2, the usage ratio of GMZB nanofiller, ethanol, epoxy resin and curing agent is 0.05~0.15g:1~2mL:5~10g:10~20g, the epoxy resin is H228-A, and the curing agent is H228-B.

[0016] Preferably, in S2, the coating process conditions of the nanocomposite coating are: coating with a wire rod coater, coating thickness 80±5 μm, curing temperature 35° C., stirring rate 400 r / min, ultrasonic treatment frequency 40 kHz, and time 15 min.

[0017] This invention has at least the following beneficial effects: By adding GO-Ti3C2TxMXene / ZIF-8@BTA (GMZB) nanofillers to epoxy resin, it produces a well-dispersed coating with a smooth, dense surface that adheres tightly to the aluminum plate. The coating also incorporates multiple protective mechanisms: GMZB provides physical barrier properties through GO / MXene, pH-responsive slow release through ZIF-8, and chemical passivation through BTA, creating a synergistic "barrier-adsorption-self-repair" effect, resulting in long-lasting corrosion resistance. Furthermore, the coating is environmentally friendly and economical, with readily available raw materials and a simple process, making it suitable for industrial production and promising application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a transmission image of the GMZB nanofiller prepared in Example 1; Figure 2 This is a microscopic morphology of the GMZB nanofiller prepared in Example 1; Figure 3is a transmission image of the nanocomposite material prepared in Comparative Example 5; Figure 4 This is a microscopic morphology of the nanocomposite material prepared in Comparative Example 5; Figure 5 Polarization curves of the coatings obtained in Example 1 and Comparative Examples 1-5; Figure 6 The resistance change spectra of the coatings prepared for Example 1 and Comparative Examples 1-5. DETAILED DESCRIPTION

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments so that those skilled in the art can implement the invention with reference to the description.

[0020] It should be understood that terms such as “having”, “including” and “comprising” used herein do not preclude the existence or addition of one or more other elements or combinations thereof.

[0021] Example 1 A method for preparing a corrosion-resistant MXene-based nanocomposite coating on aluminum and its alloys comprises the following steps: S1. Pre-treatment of aluminum plate: S1.1. Grinding: Use 400-2000 mesh SiC sandpaper to polish the aluminum plate, and rinse with deionized water after grinding; S1.2, Organic solvent degreasing: Place the cleaned aluminum plate in an acetone organic solution and degrease it at an ultrasonic frequency of 40 kHz for 15 minutes, then rinse with deionized water; S1.3, High-temperature degreasing: Place the metal substrate after degreasing with an organic solvent in a high-temperature degreasing solution at 80°C for 5 minutes. After degreasing, rinse it in deionized water at 90°C. The composition and concentration of the degreasing solution are: 45g / L sodium carbonate, 45g / L sodium phosphate, and 15g / L sodium silicate. S1.4. Electrolytic Degreasing and Oxide Film Removal: Place the aluminum plate as an electrode in the electrolyte at 12 V and 30°C for 5 min. After electrolysis, rinse the aluminum plate in deionized water at 90°C. The electrolyte composition and concentration are: 25 g / L sodium carbonate, 25 g / L sodium phosphate, and 4 g / L sodium silicate. S1.5, pickling: put the aluminum plate after electrolytic degreasing and oxide film removal into 30% nitric acid for pickling for 1 minute. After pickling, rinse thoroughly with deionized water; S1.6, Activation: After pickling, place the aluminum plate in a 30g / L boric acid solution for activation for 4 minutes. After activation, rinse with deionized water and dry for later use; S2. Preparation of nanocomposite coating: S2.1. Preparation of multilayer Ti3C2TxMXene nanosheets: 1 g of Ti3AlC2(MAX) was slowly added to 20 mL of 9 M HCl solution containing 20 g of LiF. The mixture was stirred in an oil bath at 35°C for 24 h. After the reaction was complete, the reaction product was washed several times with deionized water to remove impurities and residual acid until the pH of the supernatant reached approximately 7. The product was then freeze-dried at -60°C for 20 h to obtain multilayer Ti3C2TxMXene nanosheets. S2.2. Graphene oxide (GO) was prepared using a modified Hummers method: 1 g of graphite flakes and 0.5 g of NaNO3 were stirred in 20 mL of 18 M H2SO4 solution in an ice bath for 20 min, followed by the addition of 4 g of KMnO4 and stirring at 35°C for 2 h. Unreacted particles were then removed by adding 20 mL of deionized water and 10 mL of H2O2. The mixture was then washed several times with 3 M HCl and deionized water until neutral, and finally freeze-dried at -60°C for 24 h to obtain GO. S2.3. Construction of GO / MXene heterostructure: 1 mg / mL GO aqueous dispersion was slowly added to 1 mg / mL multilayer Ti3C2TxMXene aqueous dispersion at a mass ratio of GO to multilayer Ti3C2TxMXene of 1:1, and ultrasonicated for 15 min. The mixture was stirred at room temperature for 6 h, then washed with deionized water and centrifuged several times, and finally freeze-dried at -60 °C for 2 h to obtain covalently bonded GO-Ti3C2TxMXene, i.e., GM nanohybrid material. S2.4, ZIF-8 growth on GM surface: 0.1 g GM nanofiller was dispersed in 20 mL methanol. Separately, 0.333 g zinc nitrate and 0.732 g 2-methylimidazole were added to 15 mL methanol respectively and stirred at room temperature until dissolved to obtain two transparent solutions. Subsequently, the two solutions were added to the methanol dispersed with GM nanofiller and solvothermal synthesis was carried out at 90 °C for 24 h. The synthesized product was washed with methanol several times and dried in a vacuum oven at 60 °C for 24 h to obtain GO-Ti3C2TxMXene / ZIF-8, i.e., GMZ nanofiller; S2.5, loading BTA corrosion inhibitor: 0.15 g of the prepared GMZ nanosheets was dispersed in 10 ml of deionized water, and then 0.075 g of BTA was dispersed in 10 mL of methanol. The BTA dispersion was added dropwise to the GMZ dispersion. The mixture was stirred under vacuum at room temperature for 5 h. The suspension was washed several times with methanol by centrifugation and dried in vacuum at 40 °C for 20 h to obtain GO-Ti3C2TxMXene / ZIF-8@BTA, i.e., GMZB nanocomposite filler. 0.05 g of the prepared GMZB nanofiller was dispersed in 2 mL of ethanol, ultrasonically treated at 40 kHz for 15 min, and then mixed with 10 g of epoxy resin H228-A. After vacuum degassing, 20 g of curing agent H228-B was added and mixed to obtain a mixture. The mixture was then coated on the surface of the pretreated aluminum plate using a wire rod coater with a wire rod coating thickness of 80 μm, a curing temperature of 35°C, a stirring rate of 400 r / min, and cured at room temperature for 24 h to form a uniform and dense nanocomposite coating. S3. Post-plating treatment: Rinse the coated parts with clean water and then dry them.

[0022] Figure 1 This is a transmission image of the GMZB nanofiller prepared in Example 1. Figure 3 These are microscopic morphology pictures of the GMZB nanofiller prepared in Example 1. From these two pictures, it can be seen that the nanocomposite filler was successfully prepared in this example.

[0023] Example 2 A method for preparing a corrosion-resistant MXene-based nanocomposite coating on aluminum and its alloys comprises the following steps: S1. Pre-treatment of aluminum plate: S1.1. Grinding: Use 400-2000 mesh SiC sandpaper to polish the aluminum plate, and rinse with deionized water after grinding; S1.2, Organic solvent degreasing: Place the cleaned aluminum plate in an acetone organic solution and degrease it at an ultrasonic frequency of 30 kHz for 15 minutes, then rinse it with deionized water; S1.3, High-temperature degreasing: Place the metal substrate after degreasing with an organic solvent in a high-temperature degreasing solution at 80°C for 5 minutes. After degreasing, rinse it in deionized water at 90°C. The composition and concentration of the degreasing solution are: 45g / L sodium carbonate, 45g / L sodium phosphate, and 15g / L sodium silicate. S1.4. Electrolytic Degreasing and Oxide Film Removal: Place the aluminum plate as an electrode in the electrolyte at 12 V and 30°C for 5 min. After electrolysis, rinse the aluminum plate in deionized water at 90°C. The electrolyte composition and concentration are: 25 g / L sodium carbonate, 25 g / L sodium phosphate, and 4 g / L sodium silicate. S1.5, pickling: put the aluminum plate after electrolytic degreasing and oxide film removal into 30% nitric acid for pickling for 1 minute. After pickling, rinse thoroughly with deionized water; S1.6, Activation: After pickling, place the aluminum plate in a 30g / L boric acid solution for activation for 4 minutes. After activation, rinse with deionized water and dry for later use; S2. Preparation of nanocomposite coating: S2.1. Preparation of multilayer MXene: 1.5 g of Ti3AlC2(MAX) was slowly added to 20 mL of 9 M HCl solution containing 20 g of LiF. The mixture was stirred in an oil bath at 40°C for 24 h. After the reaction was complete, the reaction product was washed several times with deionized water to remove impurities and residual acid until the pH of the supernatant reached approximately 7. The product was freeze-dried at -60°C for 22 h to obtain multilayer Ti3C2TxMXene nanosheets. S2.2. Graphene oxide (GO) was prepared using a modified Hummers method: 1.5 g of graphite flakes and 0.8 g of NaNO₃ were stirred in 20 mL of 18 M H₂SO₄ solution on ice for 20 min, followed by the addition of 4 g of KMnO₄ and stirring at 35°C for 2 h. Unreacted particles were then removed by adding 20 mL of deionized water and 10 mL of H₂O₂. The solution was then washed several times with 3 M HCl and deionized water until neutral, and finally freeze-dried at -60°C for 24 h to obtain GO. S2.3. Construction of GO / MXene heterostructure: 1 mg / mL GO aqueous dispersion was slowly added to 1 mg / mL multilayer Ti3C2TxMXene aqueous dispersion at a mass ratio of GO to multilayer Ti3C2TxMXene of 1:1, and ultrasonicated for 15 min. The mixture was stirred at room temperature for 6 h, then washed with deionized water and centrifuged several times, and finally freeze-dried at -60 °C for 2 h to obtain covalently bonded GO-Ti3C2TxMXene, i.e., GM nanohybrid material. S2.4, ZIF-8 growth on GM surface: 0.15g GM nanofiller was dispersed in 20mL methanol. Separately, 0.412g zinc nitrate and 0.822g 2-methylimidazole were added to 20mL methanol respectively and stirred at room temperature until dissolved to obtain two transparent solutions. Subsequently, the two solutions were added to the methanol dispersed with GM nanofiller and solvothermal synthesis was carried out at 90℃ for 24h. The synthesized product was washed with methanol several times and dried in a vacuum oven at 60℃ for 24h to obtain GO-Ti3C2TxMXene / ZIF-8, i.e. GMZ nanofiller; S2.5, loading BTA corrosion inhibitor: 0.20 g of the prepared GMZ nanosheets was dispersed in 20 ml of deionized water, and then 0.15 g of BTA was dispersed in 20 mL of methanol. The BTA dispersion was added dropwise to the GMZ dispersion. The mixture was stirred under vacuum at room temperature for 5 h. The suspension was washed several times with methanol by centrifugation and dried in vacuum at 40 °C for 20 h to obtain GO-Ti3C2TxMXene / ZIF-8@BTA (GMZB) nanocomposite. 0.10 g of the prepared GMZB nanofiller was dispersed in 2 mL of ethanol and ultrasonically treated at 40 kHz for 15 min. The mixture was then mixed with 10 g of epoxy resin H228-A. After vacuum degassing, 20 g of curing agent H228-B was added and mixed to obtain a mixture. The mixture was then coated on the surface of the pretreated aluminum plate using a wire rod coater with a wire rod coating thickness of 80 μm. The curing temperature was 35°C, the stirring rate was 400 r / min, and the mixture was cured at room temperature for 24 h to form a uniform and dense nanocomposite coating. S3. Post-plating treatment: Rinse the coated parts with clean water and then dry them.

[0024] Example 3 A method for preparing a corrosion-resistant MXene-based nanocomposite coating on aluminum and its alloys comprises the following steps: S1. Pre-treatment of aluminum plate: S1.1. Grinding: Use 400-2000 mesh SiC sandpaper to polish the aluminum plate, and rinse with deionized water after grinding; S1.2, Organic solvent degreasing: Place the cleaned aluminum plate in an acetone organic solution and degrease it at an ultrasonic frequency of 30 kHz for 15 minutes, then rinse it with deionized water; S1.3, High-temperature degreasing: Place the metal substrate after degreasing with an organic solvent in a high-temperature degreasing solution at 80°C for 5 minutes. After degreasing, rinse it in deionized water at 90°C. The composition and concentration of the degreasing solution are: 45g / L sodium carbonate, 45g / L sodium phosphate, and 15g / L sodium silicate. S1.4. Electrolytic Degreasing and Oxide Film Removal: Place the aluminum plate as an electrode in the electrolyte at 12 V and 30°C for 5 min. After electrolysis, rinse the aluminum plate in deionized water at 90°C. The electrolyte composition and concentration are: 25 g / L sodium carbonate, 25 g / L sodium phosphate, and 4 g / L sodium silicate. S1.5, pickling: put the aluminum plate after electrolytic degreasing and oxide film removal into 30% nitric acid for pickling for 1 minute. After pickling, rinse thoroughly with deionized water; S1.6, Activation: After pickling, place the aluminum plate in a 30g / L boric acid solution for activation for 4 minutes. After activation, rinse with deionized water and dry for later use; S2. Preparation of nanocomposite coating: S2.1. Preparation of multilayer MXene: 2 g of Ti3AlC2(MAX) was slowly added to 20 mL of 9 M HCl solution containing 20 g of LiF. The mixture was stirred in an oil bath at 40°C for 28 h. After the reaction was complete, the reaction product was washed several times with deionized water to remove impurities and residual acid until the pH of the supernatant reached approximately 7. The product was freeze-dried at -60°C for 22 h to obtain multilayer Ti3C2TxMXene nanosheets. S2.2. Preparation of graphene oxide (GO) using a modified Hummers method: 2 g of graphite flakes and 1 g of NaNO3 were stirred in 25 mL of 18 M H2SO4 solution in an ice bath for 20 min. 5 g of KMnO4 was then added and stirred at 35°C for 2 h. Unreacted particles were then removed by adding 20 mL of deionized water and 10 mL of H2O2. The solution was then washed several times with 3 M HCl and deionized water until neutral, and finally freeze-dried at -60°C for 24 h to obtain GO. S2.3. Construction of GO / MXene heterostructure: 1 mg / mL GO aqueous dispersion was slowly added to 1 mg / mL multilayer Ti3C2TxMXene aqueous dispersion at a mass ratio of GO to multilayer Ti3C2TxMXene of 1:1, and ultrasonicated for 15 min. The mixture was stirred at room temperature for 6 h, then washed with deionized water and centrifuged several times, and finally freeze-dried at -60 °C for 2 h to obtain covalently bonded GO-Ti3C2TxMXene, i.e., GM nanohybrid material. S2.4, ZIF-8 growth on GM surface: 0.2 g GM nanofiller was dispersed in 25 mL methanol. Separately, 0.475 g zinc nitrate and 0.952 g 2-methylimidazole were added to 30 mL methanol respectively and stirred at room temperature until dissolved to obtain two transparent solutions. Subsequently, the two solutions were added to the methanol dispersed with GM nanofiller and solvothermal synthesis was carried out at 90 °C for 24 h. The synthesized product was washed with methanol several times and dried in a vacuum oven at 60 °C for 24 h to obtain GO-Ti3C2TxMXene / ZIF-8, i.e., GMZ nanofiller; S2.5, loading BTA corrosion inhibitor: 0.20 g of the prepared GMZ nanosheets was dispersed in 20 ml of deionized water, and then 0.15 g of BTA was dispersed in 20 mL of methanol. The BTA dispersion was added dropwise to the GMZ dispersion. The mixture was stirred under vacuum at room temperature for 5 h. The suspension was washed several times with methanol by centrifugation and dried in vacuum at 40 °C for 20 h to obtain GO-Ti3C2TxMXene / ZIF-8@BTA (GMZB) nanocomposite. 0.15 g of the prepared GMZB nanofiller was dispersed in 2 mL of ethanol and ultrasonically treated at 40 kHz for 15 min. The mixture was then mixed with 10 g of epoxy resin H228-A. After vacuum degassing, 20 g of curing agent H228-B was added and mixed to obtain a mixture. The mixture was then coated on the surface of the pretreated aluminum plate using a wire rod coater with a wire rod coating thickness of 80 μm. The curing temperature was 35°C, the stirring rate was 400 r / min, and the mixture was cured at room temperature for 24 h to form a uniform and dense nanocomposite coating. S3. Post-plating treatment: Rinse the coated parts with clean water and then dry them.

[0025] Comparative Example 1 This comparative example differs from Example 1 in that no nanofiller was prepared in S2, nor was it added during the coating application. During the coating application, only 2 mL of ethanol was mixed with 10 g of epoxy resin H228-A. After vacuum degassing, 20 g of curing agent H228-B was added and mixed thoroughly to obtain a mixed solution. This mixture was then applied to the pretreated aluminum plate using a wire rod coater. The wire rod coating thickness was 80 μm, the curing temperature was 35°C, the stirring rate was 400 rpm, and the coating was cured at room temperature for 24 hours to form a uniform coating.

[0026] Comparative Example 2 The difference between this comparative example and Example 1 is that in S2, only multilayer MXene is prepared and coated on an aluminum plate using the method in Example 1, and the other steps are consistent with Example 1.

[0027] Comparative Example 3 The difference between this comparative example and Example 1 is that in S2, graphene oxide (GO) is prepared only by the improved Hummers method, and is coated on the aluminum plate by the method in Example 1, and the other steps are consistent with Example 1.

[0028] Comparative Example 4 The difference between this comparative example and Example 1 is that in S2, only S2.1 to S2.3 are performed to prepare GM nanofiller, and the GM nanofiller is coated on the aluminum plate using the method in Example 1. The other steps are the same as in Example 1.

[0029] Comparative Example 5 The difference between this comparative example and Example 1 is that in S2, only S2.1 to S2.4 are performed to prepare GMZ nanofiller, and the GMZ nanofiller is coated on the aluminum plate using the method in Example 1. The other steps are the same as in Example 1.

[0030] Figure 2 This is a transmission image of the GMZ nanocomposite prepared in Comparative Example 5. Figure 4 This is the microscopic morphology of the GMZB nanofiller prepared in Comparative Example 5.

[0031] The self-corrosion currents and self-corrosion voltages of Comparative Example 1 and Examples 1-5 are shown in Table 1 below.

[0032] Table 1 As can be seen from Table 1, the nanocomposite coatings prepared in Examples 1-3 of the present invention have high self-corrosion potential, the lowest self-corrosion current, the lowest self-healing rate, and low corrosion rate; while in Comparative Example 1, since no nanofiller is added to the coating, its various performances are very poor, and it even has no self-healing ability, which shows that the GMZB nanofiller added to the coating of the present invention effectively improves the protective ability of the coating; Comparative Examples 2-3 only add multi-layer MXene nanofillers or GO, and their protective ability is still poor. Comparative Example 4 uses GM fillers prepared by constructing GO / MXene heterostructures, and its protective properties are improved to a certain extent compared with no filler added, but the protective ability is still not strong; Comparative Example 5 prepares GMZ fillers, and its protective performance is greatly improved. Its protective performance is the closest to that of Example 1 of the present invention, but since no BTA corrosion inhibitor is loaded, there is still a certain gap in the protective properties of the nanocomposite coating prepared in Example 1 of the present invention.

[0033] Figure 5 Polarization curves of the coatings obtained in Example 1 and Comparative Examples 1-5; Figure 6 The resistance change spectra of the coatings prepared in Example 1 and Comparative Examples 1-5 are shown. It can be seen from these two figures that the performance of the coating prepared using the GMZB nanofiller prepared in Example 1 of the present invention is significantly higher than that of Comparative Examples 1-5, and the coating resistance Rct still maintains the highest value after 30 days of corrosion test.

[0034] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and examples shown and described herein.

Claims

1. A method for preparing a corrosion-resistant MXene-based nanocomposite coating on aluminum and its alloys, characterized in that: The following steps are involved: S1. Metal substrate pretreatment: The metal substrate is polished, degreased with organic solvents, degreased at high temperature, electrolytically degreased and oxide film removed, pickled, and activated in sequence; S2. Preparation of nanocomposite coating: preparing GMZB nanofiller, dispersing the prepared GMZB nanofiller in ethanol, ultrasonically treating and mixing with epoxy resin, vacuum degassing, adding curing agent and mixing to obtain a mixed solution, applying the mixed solution to the pre-treated metal substrate surface, and curing at room temperature to form a uniform and dense nanocomposite coating; S3. Post-plating treatment: Rinse the coated parts with clean water and then dry them.

2. The method for preparing a corrosion-resistant MXene-based nanocomposite coating on aluminum and its alloys according to claim 1, wherein: In the above-mentioned S1, the metal substrate is an aluminum plate or an aluminum alloy plate.

3. The method for preparing a corrosion-resistant MXene-based nanocomposite coating on aluminum and its alloys according to claim 1, wherein: In said S2, the method for preparing the nanofiller is specifically as follows: S2.1, preparation of multilayer Ti3C2TxMXene nanosheets; S2.2, preparing graphene oxide GO; S2.3, slowly adding graphene oxide (GO) aqueous dispersion to multilayer Ti3C2TxMXene aqueous dispersion, stirring after ultrasonic treatment, and then washing and freeze-drying to obtain covalently bonded GO-Ti3C2TxMXene, i.e., GM nanofiller; S2.

4. Dispersing the GM nanofiller in methanol. Separately, zinc nitrate and 2-methylimidazole were added to methanol, stirred at room temperature until dissolved to obtain two transparent solutions. The two solutions were then added to the methanol containing the GM nanofiller for solvothermal synthesis. The synthesized product was washed with methanol and dried in vacuo to obtain GO-Ti3C2TxMXene / ZIF-8, i.e., GMZ nanofiller. S2.

5. Disperse the GMZ nanofiller in deionized water, disperse the corrosion inhibitor benzotriazole in methanol, then add the benzotriazole dispersion dropwise to the GMZ dispersion, stir in vacuum at room temperature, centrifuge and wash the stirred suspension with methanol several times and vacuum dry to obtain the GO-Ti3C2TxMXene / ZIF-8@BTA nanocomposite material, i.e., GMZB nanofiller.

4. The method for preparing a corrosion-resistant MXene-based nanocomposite coating on aluminum and its alloys according to claim 3, wherein: In S2.3, the concentrations of the graphene oxide GO aqueous dispersion and the multilayer Ti3C2TxMXene aqueous dispersion are both 1~10 mg / mL, and the graphene oxide GO and multilayer Ti3C2TxMXene are added at a mass ratio of 1:

1. The ultrasonic treatment frequency is 40~60 kHz, and the ultrasonic treatment is 15~30 min. Then, the mixture is stirred at room temperature for 6~8 h, and then the centrifuged mixture is washed with deionized water several times, and finally freeze-dried at -60~-80°C for 20~24 h.

5. The method for preparing a corrosion-resistant MXene-based nanocomposite coating on aluminum and its alloys according to claim 3, wherein: In the S2.4, the amount ratio of GM nanofiller and methanol is 0.1~0.2g:10~30mL, the amount ratio of zinc nitrate and methanol is 0.1~0.5g:10~30mL, the amount ratio of 2-methylimidazole and methanol is 0.5~1g:10~30mL, the mass ratio of GM nanofiller, zinc nitrate and 2-methylimidazole is 1~2:1~5:5~10, the heating temperature during solvent thermal synthesis is 90~100℃, heating is carried out for 20~30h, the vacuum drying temperature is 60~70℃, and drying is carried out for 18~24h.

6. The method for preparing a corrosion-resistant MXene-based nanocomposite coating on aluminum and its alloys according to claim 3, wherein: In the S2.5, the dosage ratio of GMZ nanofiller and deionized water is 0.15~0.20g:10~20mL, the dosage ratio of corrosion inhibitor benzotriazole and methanol is 0.075~0.150g:10~20mL, the mass ratio of GMZ nanofiller and corrosion inhibitor benzotriazole is 2~3:1~2, vacuum stirring is performed for 5h, the vacuum drying temperature is 40~60℃, and vacuum drying is performed for 18~24h.

7. The method for preparing a corrosion-resistant MXene-based nanocomposite coating on aluminum and its alloys according to claim 1, wherein: In the S2, the usage ratio of GMZB nanofiller, ethanol, epoxy resin and curing agent is 0.05~0.15g:1~2mL:5~10g:10~20g, the epoxy resin is H228-A, and the curing agent is H228-B.

8. The method for preparing a corrosion-resistant MXene-based nanocomposite coating on aluminum and its alloys according to claim 1, wherein: In S2, the coating process conditions of the nanocomposite coating are: coating with a wire rod coater, coating thickness of 80±5 μm, curing temperature of 35° C., stirring rate of 400 r / min, ultrasonic treatment frequency of 40-60 kHz, and ultrasonic time of 15-20 min.

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