Ti3C2@PDA@MMT-Zn composite material, its preparation method and composite coating

Abstract

This invention provides a Ti3C2@PDA@MMT-Zn composite material, its preparation method, and a composite coating. The Ti3C2@PDA@MMT-Zn composite material comprises the following components by mass fraction: Ti3C2: 0.2 parts, MMT: 0.2 parts, zinc nitrate corrosion inhibitor: 0.2 parts, dopamine hydrochloride: 0.2 parts, Tris-hydroxymethylaminomethane buffer solution: 0.5 parts, pH adjuster: 0.1 parts, and deionized water: 120 parts. The Ti3C2 two-dimensional nanomaterial is obtained by mixing and stirring Ti3AlC2 as a precursor and HF aqueous solution as the etching system. The Ti3C2@PDA@MMT-Zn composite material of this invention not only ensures its dispersibility and compatibility in epoxy coatings but also effectively combines the physical shielding effect of two-dimensional materials with the active self-healing properties of corrosion inhibitors to synergistically improve the anti-corrosion performance of the coating.

Description

Technical Field

[0001] This invention relates to the field of metal protection technology, and particularly to a Ti3C2@PDA@MMT-Zn composite material. The invention also relates to a method for preparing the Ti3C2@PDA@MMT-Zn composite material. Furthermore, the invention also relates to a composite coating having the Ti3C2@PDA@MMT-Zn composite material. Background Technology

[0002] Metals and their alloys are widely used in various industries due to their excellent mechanical properties. However, corrosion is an unavoidable problem faced by metallic materials during use. Metal corrosion causes enormous resource waste, economic losses, and safety hazards to countries and societies, and has always been one of the most pressing global challenges to address. Research on steel corrosion has been ongoing by scientists both domestically and internationally, reporting various corrosion prevention methods and technologies, including electrochemical protection, the addition of corrosion inhibitors, and the application of anti-corrosion coatings. Among these, applying an anti-corrosion coating to the metal surface is the simplest and most efficient method for metal corrosion prevention.

[0003] Organic coatings are generally considered as insulating layers, protecting metals from corrosion by preventing or delaying the penetration of aqueous solutions into the interface between the substrate metal and the coating. However, aqueous solutions can always penetrate into the coating through swelling and micropores left on the surface and inside the coating due to the evaporation of organic solvents, making it difficult for organic coatings to meet long-term industrial protective requirements. Therefore, additives such as nanofillers (SiO2, ZnO, hydrotalcite, montmorillonite (MMT), graphene, etc.) are selectively added to the coating to improve the physical barrier properties of the organic coating and enhance its protective performance.

[0004] MMT is a clay composed of nano-thick silicate sheets. Its basic structural unit is a 2:1 layered structure consisting of two layers of silica sheets surrounding a central alumina octahedral sheet. MMT has attracted much attention in the coating field due to its unique layered structure and large specific surface area.

[0005] Ti3C2, as a high aspect ratio two-dimensional sheet nanofiller, possesses excellent spatial barrier effects. It can be used to prepare anti-corrosion films with good impermeability, and also as a filler added to organic anti-corrosion coatings to fill defects generated during resin curing, significantly extending the coating's service life. However, current research on Ti3C2 in the field of corrosion protection is still in its early stages, and its further application is limited by unfavorable factors such as poor dispersibility and easy oxidation. Summary of the Invention

[0006] In view of this, the present invention aims to propose a Ti3C2@PDA@MMT-Zn composite material, in order to...

[0007] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0008] A Ti3C2@PDA@MMT-Zn composite material, comprising the following components by mass fraction: Ti3C2: 0.2 parts, MMT: 0.2 parts, zinc nitrate corrosion inhibitor: 0.2 parts, dopamine hydrochloride: 0.2 parts, tris(hydroxymethyl)aminomethane (Tris) buffer solution: 0.5 parts, pH adjuster: 0.1 parts, and deionized water: 120 parts;

[0009] Among them, the Ti3C2 two-dimensional nanomaterial is obtained by mixing and stirring Ti3AlC2 as a precursor and HF aqueous solution as an etching system.

[0010] Compared with the prior art, the present invention has the following advantages:

[0011] The Ti3C2@PDA@MMT-Zn composite material of the present invention uses Ti3C2 as the matrix material. Its small size effect can fill the pores of the coating and increase the density of the coating. Furthermore, the two-dimensional lamellar structure of Ti3C2 can form a labyrinth effect in the coating to extend the diffusion path of corrosive ions, thereby effectively improving the physical barrier performance of the coating and enhancing its passive shielding performance.

[0012] Furthermore, the Zn in the Ti3C2@PDA@MMT-Zn composite material 2+ Both MMT-Zn and PDA have certain corrosion-inhibiting effects and can synergistically improve the corrosion resistance of the coating. When the coating is damaged, MMT-Zn can release Zn through ion exchange. 2+ Corrosion inhibitors slow down metal corrosion, while the functional groups on the PDA surface can interact with Fe. 2+ or Fe 3+ A chelate is formed and adsorbed at the damaged area of ​​the coating, reacting with the released Zn. 2+ Corrosion inhibitors work synergistically to form a passivation film on the surface of the metal substrate, preventing further corrosion, improving the anti-corrosion performance of the coating, and giving the coating a certain degree of self-healing properties.

[0013] Meanwhile, PDA has strong adhesion. After adsorbing onto the Ti3C2 surface, it improves the antioxidant properties of two-dimensional Ti3C2 on the one hand, and the presence of amino and hydroxyl groups in the molecule also enhances the compatibility and dispersibility of the composite material with epoxy resin, thereby improving the bonding strength between the coating and the substrate.

[0014] In summary, the Ti3C2@PDA@MMT-Zn composite material not only ensures its dispersibility and compatibility in epoxy coatings, but also effectively combines the physical shielding effect of two-dimensional materials with the active self-healing properties of corrosion inhibitors to synergistically improve the anti-corrosion performance of the coating.

[0015] Another objective of this invention is to provide a method for preparing a Ti3C2@PDA@MMT-Zn composite material, the method comprising:

[0016] Step A: Preparation of Ti3C2 two-dimensional nanomaterial powder: A certain mass of Ti3AlC2 is slowly added to a certain mass fraction of HF aqueous solution for etching reaction, and washed with deionized water until pH>6. The lower layer precipitate is taken off and cooled and dried to obtain Ti3C2 two-dimensional nanomaterial powder.

[0017] Step B: Preparation of Ti3C2@PDA@MMT-Zn composite material:

[0018] First, the Ti3C2 two-dimensional nanomaterial powder obtained in step A is dispersed in a Tris-HCl buffer solution with a pH of 8.5, dopamine powder is added, and the mixture is magnetically stirred for a certain period of time to obtain a suspension of Ti3C2@PDA composite material.

[0019] Next, the suspension of the obtained Ti3C2@PDA composite material was centrifuged, the precipitate was removed and washed with distilled water, and then redispersed in a suspension containing a certain concentration of MMT and zinc nitrate corrosion inhibitor. The pH of the system was adjusted to 3-4, and stirring was continued for a certain period of time. During the stirring process, N2 protective gas was introduced.

[0020] Finally, the suspension was centrifuged, the lower precipitate was removed and washed with ethanol and distilled water, and then freeze-dried to obtain the Ti3C2@PDA@MMT-Zn composite material.

[0021] Furthermore, the HF aqueous solution in step A has a mass fraction of 20-50%.

[0022] Furthermore, the etching reaction temperature in step A is between 20-40°C, and the etching reaction time is between 12-48 hours.

[0023] Furthermore, in step B, a certain amount of tris(hydroxymethyl)aminomethane (Tris) is dispersed in deionized water, a pH adjuster is added to make the solution pH 8.5, and the stirring time is 12-48 hours to obtain a Tris-HCl buffer solution.

[0024] Furthermore, in step B, the molar ratio of Ti3C2 powder to MMT is between 0.5 and 2.0.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] The preparation method of the Ti3C2@PDA@MMT-Zn composite material of the present invention can ensure its dispersibility and compatibility in epoxy coating, and can effectively combine the physical shielding effect of two-dimensional materials and the active self-healing performance of corrosion inhibitors to synergistically improve the anti-corrosion performance of the coating.

[0027] Furthermore, another object of the present invention is to provide a composite coating comprising the Ti3C2@PDA@MMT-Zn composite material as described above, wherein the composite coating is prepared by the following method:

[0028] Add 0.2-2 wt% Ti3C2@PDA@MMT-Zn composite material to waterborne epoxy resin, stir for 3-5 min, and then sonicate for 5-10 min to obtain composite coating.

[0029] The composite coating of this invention, through the addition of Ti3C2@PDA@MMT-Zn composite material, not only exhibits good dispersibility and compatibility with waterborne epoxy resin, but also achieves Zn... 2+ The corrosion inhibitor exhibits a stimulus-response release under various environmental systems, including acids, alkalis, and salts. Waterborne epoxy composite coatings prepared using it as a functional anti-corrosion filler can fully utilize the physical shielding effect of two-dimensional Ti3C2 material, the ion exchange properties of montmorillonite, and the effects of polydopamine and Zn. 2+ The corrosion inhibitors work synergistically to enhance the anti-corrosion performance of the composite coating, giving it both active and passive protection functions as well as a certain degree of self-healing properties, thus achieving a long-lasting and highly effective anti-corrosion effect. Attached Figure Description

[0030] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0031] Figure 1 The dispersion behavior of Ti3C2 and Ti3C2@PDA@MMT-Zn composite materials in epoxy resin slurry at different times according to embodiments of the present invention;

[0032] Figure 2 Zn in the Ti3C2@PDA@MMT-Zn composite material described in the embodiments of the present invention 2+ Release curves in different system environments;

[0033] Figure 3Bode plots of the blank epoxy coating described in this embodiment of the invention after immersion in 3.5% NaCl for different times;

[0034] Figure 4 Bode images of the Ti3C2@PDA@MMT-Zn composite epoxy coating described in this embodiment of the invention after immersion in 3.5% NaCl for different times;

[0035] Figure 5 Bode plot of the scratch-resistant blank epoxy coating described in this embodiment of the invention after immersion in 3.5% NaCl for 72 hours;

[0036] Figure 6 Bode plot of the scratch-resistant Ti3C2@PDA@MMT-Zn composite epoxy coating described in this embodiment of the invention after immersion in 3.5% NaCl for 72 hours;

[0037] Figure 7 Digital and SEM images of the scratch-marked blank epoxy coating and the composite epoxy coating with added Ti3C2@PDA@MMT-Zn as described in the embodiments of the present invention after immersion in 3.5% NaCl for 72 hours; Detailed Implementation

[0038] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0039] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0040] This embodiment relates to a Ti3C2@PDA@MMT-Zn composite material. In terms of overall design, the Ti3C2@PDA@MMT-Zn composite material includes the following components in parts by mass: Ti3C2: 0.2 parts, MMT: 0.2 parts, zinc nitrate corrosion inhibitor: 0.2 parts, dopamine hydrochloride: 0.2 parts, Tris-hydroxymethylaminomethane buffer solution: 0.5 parts, pH adjuster: 0.1 parts, and deionized water: 120 parts.

[0041] Among them, the Ti3C2 two-dimensional nanomaterial is obtained by mixing and stirring Ti3AlC2 as a precursor and HF aqueous solution as an etching system.

[0042] The Ti3C2@PDA@MMT-Zn composite material of this embodiment uses the two-dimensional material Ti3C2 as the matrix. Its small size effect can fill the pores of the coating and increase the density of the coating. Furthermore, the lamellar structure of Ti3C2 can form a labyrinth effect in the coating, which prolongs the diffusion path of corrosive ions, thereby improving the physical shielding performance of the coating, that is, improving the passive shielding performance of the coating.

[0043] Furthermore, in the Ti3C2@PDA@MMT-Zn composite material, MMT-Zn, which has ion exchange capabilities, can release Zn with corrosion-inhibiting effects through ion exchange. 2+ It can impart self-healing properties to the coating, and its synergistic effect with polydopamine can significantly improve the coating's corrosion resistance to metals. At the same time, the introduction of polydopamine into the composite material improves both the dispersibility of Ti3C2 in epoxy resin and its oxidation resistance.

[0044] Therefore, the Ti3C2@PDA@MMT-Zn composite material can not only ensure its dispersibility and compatibility in epoxy coatings, but also effectively combine the physical shielding effect of two-dimensional materials and the active self-healing performance of corrosion inhibitors to synergistically improve the anti-corrosion performance of the coating.

[0045] Regarding the Ti3C2@PDA@MMT-Zn composite material described above in this embodiment, this embodiment also proposes a method for preparing the Ti3C2@PDA@MMT-Zn composite material. The preparation method mainly includes the following in its overall design:

[0046] Step A: Preparation of Ti3C2 two-dimensional nanomaterial powder: A certain mass of Ti3AlC2 powder is slowly added to a certain mass fraction of HF aqueous solution for etching reaction, and washed with deionized water until pH>6. The lower precipitate is taken out and freeze-dried to obtain Ti3C2 two-dimensional nanomaterial powder.

[0047] Step B: Preparation of Ti3C2@PDA@MMT-Zn composite material:

[0048] First, the Ti3C2 two-dimensional nanomaterial powder prepared in step A is dispersed in a Tris-HCl buffer solution with a pH of about 8.5, dopamine powder is added, and the mixture is magnetically stirred for a certain period of time, for example, 24 hours, to obtain a suspension of Ti3C2@PDA composite material.

[0049] Next, the obtained Ti3C2@PDA composite material suspension was centrifuged, the precipitate was removed and washed with distilled water, and then redispersed in a suspension containing a certain concentration of MMT and zinc nitrate corrosion inhibitor. The pH of the system was adjusted to 3-4, and stirring was continued for a certain period of time. During the stirring process, N2 protective gas was introduced.

[0050] Finally, the suspension was centrifuged, the lower precipitate was removed and washed with ethanol and distilled water, and then freeze-dried to obtain the Ti3C2@PDA@MMT-Zn composite material.

[0051] In step A, the mass fraction of the HF aqueous solution is 20-50%, and in specific preparation, the mass fraction of the HF aqueous solution can be 20%, 25%, 30%, 35%, 40%, 45%, or 50%.

[0052] In addition, the etching reaction temperature in step A is between 20-40°C, and the etching reaction time is between 12-48 hours. Specifically, the etching reaction temperature can be set to, for example, 20°C, 25°C, 30°C, 35°C, or 40°C, and the etching reaction time can be set to, for example, 12 hours, 15 hours, 18 hours, 20 hours, 22 hours, 25 hours, 28 hours, 30 hours, 32 hours, 35 hours, 38 hours, or 40 hours.

[0053] In addition, in step B above, a certain amount of tris(hydroxymethyl)aminomethane (Tris) is dispersed in deionized water, a pH adjuster is added to adjust the pH to 8.5, and the stirring time is 12-48 h to obtain a Tris-HCl buffer solution. Furthermore, suspensions of Ti3C2, MMT, and zinc salt are mixed and magnetically stirred for 12-48 h at a temperature controlled between 25-100 °C.

[0054] In a preferred embodiment of the present invention, the molar ratio of Ti3C2 powder to MMT in step B is between 0.5 and 2.0, and in specific preparation, the molar ratio of Ti3C2 powder to MMT can be, for example, 0.5, 0.8, 1.0, 1.5 or 2.0.

[0055] Based on the preparation method described above, the preparation of the Ti3C2@PDA@MMT-Zn composite material of this embodiment will be specifically described below with several examples.

[0056] Example 1

[0057] This embodiment relates to the preparation of Ti3C2@PDA@MMT-Zn composite material, and the specific preparation steps are as follows:

[0058] (1) 1.0 g Ti3AlC2 was slowly added to 30 ml of 40% HF and etched at 35 °C for 24 h. Afterwards, the mixture was washed several times with deionized water until the pH was > 6. The lower precipitate was then freeze-dried to obtain Ti3C2 two-dimensional nanomaterials.

[0059] (2) Weigh 1.0g of Ti3C2 powder prepared in the above steps, disperse it in 80ml of deionized water, add 0.5g of dopamine hydrochloride and 20ml of Tris-HCl buffer solution, adjust the pH to 8.5, stir magnetically at 600rpm for 24h, centrifuge the mixed solution, wash the lower precipitate with anhydrous ethanol and deionized water until the pH is neutral, and freeze dry to obtain Ti3C2@PDA composite material.

[0060] (3) Weigh 0.5g of MMT powder and disperse it in 100ml of 1mol / L zinc nitrate solution. Adjust the pH of the system to 3-4, and add 1.0g of the prepared Ti3C2@PDA powder. The reaction temperature is 30℃, and the mixture is magnetically stirred for 12h. During the stirring process, N2 protective gas is introduced. Afterward, the suspension is centrifuged and washed until the pH is neutral. The precipitate is freeze-dried and ground to obtain the Ti3C2@PDA@MMT-Zn composite material.

[0061] The Ti3C2@PDA@MMT-Zn composite material prepared above, with a mass fraction of 0.5wt%, was added to an aqueous epoxy resin, stirred for 3-5 minutes, and then sonicated for 5-10 minutes to obtain a composite coating. The composite coating was then applied to a Q235 steel plate.

[0062] Example 2

[0063] (1) 1.0 g Ti3AlC2 was slowly added to 30 ml of 50% HF and etched at 25 °C for 36 h. Afterwards, the mixture was washed several times with deionized water until the pH was > 6. The lower precipitate was then freeze-dried to obtain Ti3C2 two-dimensional nanomaterials.

[0064] (2) Weigh 1.0g of Ti3C2 powder prepared in the above steps, disperse it in 80ml of deionized water, add 0.5g of dopamine hydrochloride and 20ml of Tris-HCl buffer solution, adjust the pH to 8.1, stir magnetically for 12h at 600rpm, centrifuge the mixed solution, wash the lower precipitate with anhydrous ethanol and deionized water until the pH is neutral, and freeze dry to obtain Ti3C2@PDA composite material.

[0065] (3) Weigh 1.0 g of MMT powder and disperse it in 100 ml of 1 mol / L zinc nitrate solution. Adjust the pH of the system to 3-4, and add 1.0 g of the prepared Ti3C2@PDA powder. The reaction temperature is 50℃, and the mixture is magnetically stirred for 24 h. During the stirring process, N2 protective gas is introduced. Afterward, the suspension is centrifuged and washed until the pH is neutral. The precipitate is freeze-dried and ground to obtain the Ti3C2@PDA@MMT-Zn composite material.

[0066] The Ti3C2@PDA@MMT-Zn composite material prepared above, with a mass fraction of 1.5 wt%, was added to an aqueous epoxy resin and stirred for 3-5 min, followed by ultrasonication for 5-10 min to obtain a composite coating. This composite coating was then applied to a Q235 steel plate.

[0067] Example 3

[0068] (1) 1.0 g Ti3AlC2 was slowly added to 20 ml of 50% HF and etched at 30 °C for 24 h. Afterwards, the mixture was washed several times with deionized water until the pH was > 6. The lower precipitate was then freeze-dried to obtain Ti3C2 two-dimensional nanomaterials.

[0069] (2) Weigh 1.0g of Ti3C2 powder prepared in the above steps, disperse it in 80ml of deionized water, add 0.5g of dopamine hydrochloride and 20ml of Tris-HCl buffer solution, adjust the pH to 8.2, stir magnetically for 36h at 600rpm, centrifuge the mixed solution, wash the lower precipitate with anhydrous ethanol and deionized water until the pH is neutral, and then freeze dry to obtain Ti3C2@PDA composite material.

[0070] (3) Weigh 1.5g of MMT powder and disperse it in 100ml of 1mol / L zinc nitrate solution. Adjust the pH of the system to 3-4, and add 1.0g of the prepared Ti3C2@PDA powder. The reaction temperature is 75℃, and the mixture is magnetically stirred for 48h. During the stirring process, N2 protective gas is introduced. Afterward, the suspension is centrifuged and washed until the pH is neutral. The precipitate is freeze-dried and ground to obtain the Ti3C2@PDA@MMT-Zn composite material.

[0071] The Ti3C2@PDA@MMT-Zn composite material prepared above, with a mass fraction of 1.0 wt%, was added to an aqueous epoxy resin and stirred for 3-5 min. Then, it was sonicated for 5-10 min to obtain a composite coating. The composite coating was then applied to a Q235 steel plate.

[0072] Example 4

[0073] (1) 1.0 g Ti3AlC2 was slowly added to 10 ml of 30% HF and etched at 40 °C for 48 h. Afterwards, the mixture was washed several times with deionized water until the pH was > 6. The lower precipitate was then freeze-dried to obtain Ti3C2 two-dimensional nanomaterials.

[0074] (2) Weigh 1.0g of Ti3C2 powder prepared in the above steps, disperse it in 80ml of deionized water, add 0.5g of dopamine hydrochloride and 20ml of Tris-HCl buffer solution, adjust the pH to 8.3, stir magnetically at 600rpm for 48h, centrifuge the mixed solution, wash the lower precipitate with anhydrous ethanol and deionized water until the pH is neutral, and freeze dry to obtain Ti3C2@PDA composite material.

[0075] (3) Weigh 2.0g of MMT powder and disperse it in 100ml of 1mol / L zinc nitrate solution. Adjust the pH of the system to 3-4, and add 1.0g of the prepared Ti3C2@PDA powder. The reaction temperature is 50℃, and the mixture is magnetically stirred for 24h. During the stirring process, N2 protective gas is introduced. Afterward, the suspension is centrifuged and washed until the pH is neutral. The precipitate is freeze-dried and ground to obtain the Ti3C2@PDA@MMT-Zn composite material.

[0076] The Ti3C2@PDA@MMT-Zn composite material prepared above, with a mass fraction of 0.5 wt%, was added to epoxy resin, stirred for 3-5 min, and then sonicated for 5-10 min to obtain a composite coating. The composite coating was then applied to a Q235 steel plate.

[0077] Example 5

[0078] (1) 1.0 g Ti3AlC2 was slowly added to 25 ml of 40% HF and etched at 20 °C for 20 h. Afterwards, the mixture was washed several times with deionized water until the pH was > 6. The lower precipitate was then freeze-dried to obtain the Ti3C2 two-dimensional nanomaterial.

[0079] (2) Weigh 1.0g of Ti3C2 powder prepared in the above steps, disperse it in 80ml of deionized water, add 0.5g of dopamine hydrochloride and 20ml of Tris-HCl buffer solution, adjust the pH to 8.4, stir magnetically at 600rpm for 24h, centrifuge the mixed solution, wash the lower precipitate with anhydrous ethanol and deionized water until the pH is neutral, and then freeze dry to obtain Ti3C2@PDA composite material.

[0080] (3) Weigh 1.0 g of MMT powder and disperse it in 100 ml of 1 mol / L zinc nitrate solution. Adjust the pH of the system to 3-4, and add 1.0 g of the prepared Ti3C2@PDA powder. The reaction temperature is 50℃, and the mixture is magnetically stirred for 48 h. During the stirring process, N2 protective gas is introduced. Afterward, the suspension is centrifuged and washed until the pH is neutral. The precipitate is freeze-dried and ground to obtain the Ti3C2@PDA@MMT-Zn composite material.

[0081] The Ti3C2@PDA@MMT-Zn composite material prepared above, with a mass fraction of 1.5 wt%, was added to an aqueous epoxy resin, stirred for 3-5 min, and then sonicated for 5-10 min to obtain a composite coating. The composite coating was then applied to a Q235 steel plate.

[0082] In this invention, the Ti3C2@PDA@MMT-Zn composite material prepared according to the above preparation examples is used to obtain a two-dimensional layered material of Ti3C2 by etching Ti3AlC2 with HF. Polydopamine is then used to modify the two-dimensional layered material of Ti3C2 to improve its corrosion resistance, oxidation resistance, and its dispersibility and compatibility in epoxy resins. Subsequently, an ion-exchange type MMT-Zn functional corrosion inhibitor is adsorbed onto its surface using electrostatic interactions to obtain the Ti3C2@PDA@MMT-Zn composite material.

[0083] Then, the Ti3C2@PDA@MMT-Zn composite material was added to waterborne epoxy resin as a functional filler to obtain a composite coating with Ti3C2@PDA@MMT-Zn.

[0084] The method for preparing the Ti3C2@PDA@MMT-Zn composite material of the present invention ensures its dispersibility and compatibility in epoxy coatings. Furthermore, it effectively combines the physical shielding effect of two-dimensional materials with the active self-healing properties of corrosion inhibitors to synergistically enhance the anti-corrosion performance of the coating. It also exhibits good controlled-release characteristics and multi-response performance under different system environments (acids, alkalis, salts). Moreover, waterborne epoxy composite coatings prepared using it as a filler demonstrate excellent anti-corrosion performance and a certain degree of self-healing properties.

[0085] To better illustrate the superior controlled-release characteristics and multi-response performance of the Ti3C2@PDA@MMT-Zn composite material of the present invention under different system environments (acid, alkali, salt), the following experiments and experimental results will be used to provide a detailed explanation.

[0086] (1) Dispersion performance

[0087] A certain amount of Ti3C2 and Ti3C2@PDA@MMT-Zn samples were weighed and added to epoxy resin, with each sample added at 0.5 wt% of the epoxy resin. The two samples were dispersed in the epoxy resin by ultrasonic treatment, and their dispersibility in the epoxy resin slurry was investigated. The results are as follows: Figure 1 As shown.

[0088] from Figure 1As can be seen, ultrasonic treatment can ensure uniform dispersion of both samples in the epoxy resin slurry within a short time (1 h). However, when the standing time reaches 360 h, a noticeable sedimentation is observed at the bottom of the epoxy slurry with added Ti3C2, while no obvious sedimentation is observed in the epoxy resin slurry with added Ti3C2@PDA@MMT-Zn. This indicates that the Ti3C2@PDA@MMT-Zn composite material has better dispersibility than the Ti3C2 material. This is because polydopamine contains a large number of hydrophilic catechol groups and amino groups, which improves the dispersibility of the material in the epoxy resin slurry.

[0089] (2) Release performance

[0090] First, 0.1 g of Ti3C2@PDA@MMT-Zn material was weighed and added to 100 ml of solutions in different environmental systems (acid, alkali, and salt). At appropriate time intervals, 5 ml of the release medium was collected, and equal volumes of deionized water at different pH values ​​were added. Then, the zinc ion concentration in the release medium at different times was measured using a UV-Vis spectrophotometer. The data were compiled to obtain the zinc ion release curves, as shown below. Figure 2 As shown.

[0091] like Figure 2 As shown in (a), in a neutral solution, Zn in Ti3C2@PDA@MMT-Zn 2+ The release rate is very slow, with a release amount of only about 3%. This may be due to the positively charged Zn in the interlayer. 2+ There is an electrostatic force between it and the negatively charged MMT layer; in acidic solutions, its release rate increases significantly and gradually increases as the pH value decreases.

[0092] from Figure 2 As can be observed in (b), alkali can also accelerate the reaction of Zn in Ti3C2@PDA@MMT-Zn. 2+ The release rate increases with increasing OH- concentration in the solution. Figure 2 (c) Ti3C2@PDA@MMT-Zn contains Zn 2+ The release rate in NaCl solution is significantly higher than that in distilled water, and it gradually increases with increasing NaCl concentration. This phenomenon is due to the strong ion exchange capacity of MMT, which allows Zn to be released from the interlayer in NaCl solution. 2+ It can undergo ion exchange with Na+ in the solution, transferring a large amount of Zn. 2+ Released into the solution.

[0093] Furthermore, to better illustrate the anti-corrosion and sustained-release properties of the Ti3C2@PDA@MMT-Zn composite material, in this invention, the Ti3C2@PDA@MMT-Zn composite material was added to epoxy resin. Then, using a classic three-electrode system (a Q235 steel plate coated with epoxy resin as the working electrode, a saturated calomel electrode as the reference electrode, and a platinum sheet electrode as the counter electrode), electrochemical impedance spectroscopy was performed on the coated steel plate after immersion in 3.5% NaCl solution for different times using an electrochemical workstation. The results are as follows: Figures 3 to 7 As shown.

[0094] from Figure 3 It can be seen that the impedance value of the blank epoxy coating in the initial stage of immersion is around 10. 7 Ω·cm 2 Around 10 days, the impedance value decreased continuously with prolonged soaking time, reaching 10. 6 Ω·cm 2 This indicates that the corrosive medium has penetrated to the coating / metal substrate interface and corrosion has occurred. However, for the composite coating with added Ti3C2@PDA@MMT-Zn composite material (…),… Figure 4 Its impedance value is 10 during the initial soaking stage. 10 Ω·cm 2 The impedance value was three orders of magnitude higher than that of the blank coating, indicating that the introduction of the Ti3C2@PDA@MMT-Zn composite material into the coating improved its corrosion resistance. Simultaneously, its impedance value remained at a high level (10) throughout the immersion process. 10 Ω·cm 2 The impedance values ​​of the composite coatings with added Ti3C2@PDA@MMT-Zn composite material are all higher than those of the blank coating, indicating that the composite coating with added Ti3C2@PDA@MMT-Zn composite material has good anti-corrosion performance.

[0095] Furthermore, scratch tests were conducted on the composite coating with added Ti3C2@PDA@MMT-Zn and the blank coating in this invention, and the corresponding impedance tests were performed as follows: Figure 5 and Figure 6 As shown, photographs of the scratch-marked blank epoxy coating and the scratch-marked Ti3C2@PDA@MMT-Zn composite coating after immersion in 3.5% NaCl for 72 hours are as follows. Figure 7 As shown.

[0096] Depend on Figure 5 It can be seen that during the entire immersion period, the low-frequency impedance value of the scratch-free coating was around 4.3 on the first day of immersion, but after 72 hours of immersion, the value of the scratch-free coating dropped to around 3.5. However, for the composite coating containing Ti3C2@PDA@MMT-Zn... Figure 6The impedance value in the low-frequency region was around 4.5 on the first day of immersion. With prolonged immersion time, the impedance value in the low-frequency region decreased only slightly, reaching approximately 4.2 after 72 hours of immersion. This indicates that the composite coating containing Ti3C2@PDA@MMT-Zn composite material exhibits good self-healing and corrosion-resistant properties.

[0097] Furthermore, photos showing the soaking time through scratches, such as... Figure 7 As shown, there are no obvious corrosion products on the metal substrate at the scratches of the composite coating, indicating that the zinc ions and dopamine released from the Ti3C2@PDA@MMT-Zn composite material form a protective film on the metal surface, thereby preventing further corrosion. In other words, the Ti3C2@PDA@MMT-Zn composite material can release corrosion inhibitors in the coating, improving the anti-corrosion performance of the coating.

[0098] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A Ti3C2@PDA@MMT-Zn composite material, characterized in that: The Ti3C2@PDA@MMT-Zn composite material comprises the following components in parts by weight: Ti3C2: 0.2 parts, MMT: 0.2 parts, zinc nitrate corrosion inhibitor: 0.2 parts, dopamine hydrochloride: 0.2 parts, Tris-hydroxymethylaminomethane buffer solution: 0.5 parts, pH adjuster: 0.1 parts, and deionized water: 120 parts. Among them, the Ti3C2 two-dimensional nanomaterial was obtained by mixing and stirring Ti3AlC2 as a precursor and HF aqueous solution as an etching system. The preparation method of the Ti3C2@PDA@MMT-Zn composite material includes the following steps: Step A: Preparation of Ti3C2 two-dimensional nanomaterial powder: A certain mass of Ti3AlC2 is slowly added to a certain mass fraction of HF aqueous solution for etching reaction, and washed with deionized water until pH>6. The lower layer precipitate is taken off and cooled and dried to obtain Ti3C2 two-dimensional nanomaterial powder. Step B: Preparation of Ti3C2@PDA@MMT-Zn composite material: First, the Ti3C2 two-dimensional nanomaterial powder obtained in step A is dispersed in a Tris-HCl buffer solution with a pH of 8.5, dopamine powder is added, and the mixture is magnetically stirred for a certain period of time to obtain a suspension of Ti3C2@PDA composite material. Next, the suspension of the obtained Ti3C2@PDA composite material was centrifuged, the precipitate was removed and washed with distilled water, and then redispersed in a suspension containing a certain concentration of MMT and zinc nitrate corrosion inhibitor. The pH of the system was adjusted to 3-4, and stirring was continued for a certain period of time. During the stirring process, N2 protective gas was introduced. Finally, the suspension was centrifuged, the lower precipitate was removed and washed with ethanol and distilled water, and then freeze-dried to obtain the Ti3C2@PDA@MMT-Zn composite material.

2. A method for preparing a Ti3C2@PDA@MMT-Zn composite material, characterized in that: The preparation method includes: Step A: Preparation of Ti3C2 two-dimensional nanomaterial powder: A certain mass of Ti3AlC2 is slowly added to a certain mass fraction of HF aqueous solution for etching reaction, and washed with deionized water until pH>6. The lower layer precipitate is taken off and cooled and dried to obtain Ti3C2 two-dimensional nanomaterial powder. Step B: Preparation of Ti3C2@PDA@MMT-Zn composite material: First, the Ti3C2 two-dimensional nanomaterial powder obtained in step A is dispersed in a Tris-HCl buffer solution with a pH of 8.5, dopamine powder is added, and the mixture is magnetically stirred for a certain period of time to obtain a suspension of Ti3C2@PDA composite material. Next, the suspension of the obtained Ti3C2@PDA composite material was centrifuged, the precipitate was removed and washed with distilled water, and then redispersed in a suspension containing a certain concentration of MMT and zinc nitrate corrosion inhibitor. The pH of the system was adjusted to 3-4, and stirring was continued for a certain period of time. During the stirring process, N2 protective gas was introduced. Finally, the suspension was centrifuged, the lower precipitate was removed and washed with ethanol and distilled water, and then freeze-dried to obtain the Ti3C2@PDA@MMT-Zn composite material.

3. The preparation method of the Ti3C2@PDA@MMT-Zn composite material according to claim 2, characterized in that: The HF aqueous solution in step A has a mass fraction of 20-50%.

4. The preparation method of the Ti3C2@PDA@MMT-Zn composite material according to claim 2, characterized in that: The etching reaction temperature in step A is between 20-40°C, and the etching reaction time is between 12-48 h.

5. The preparation method of the Ti3C2@PDA@MMT-Zn composite material according to claim 2, characterized in that: In step B, a certain amount of tris(hydroxymethyl)aminomethane (Tris) is dispersed in deionized water, a pH adjuster is added to make the solution pH 8.5, and the stirring time is 12-48 h to obtain a Tris-HCl buffer solution.

6. The method for preparing the Ti3C2@PDA@MMT-Zn composite material according to claim 2, characterized in that: In step B, the molar ratio of Ti3C2 powder to MMT is between 0.5 and 2.

0.

7. A composite coating, characterized in that, The composite coating includes the Ti3C2@PDA@MMT-Zn composite material of claim 1, and the composite coating is prepared by the following method: Add 0.2-2 wt% Ti3C2@PDA@MMT-Zn composite material to waterborne epoxy resin, stir for 3-5 min, and then sonicate for 5-10 min to obtain composite coating.

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