Epoxy composite coating with synergistic barrier, passivation and corrosion inhibition effects and preparation method thereof

Abstract

The present invention provides an epoxy composite coating with synergistic barrier, passivation and corrosion inhibition effects and a preparation method thereof. The epoxy composite coating comprises RE 3+ @PANI@MXene composite nanoparticles and self-curing epoxy resin, wherein the RE 3+ @PANI@MXene composite nanoparticles composed of rare earth cations RE 3+ Made from MXene nanosheets in situ modified with polyaniline, the epoxy composite coating described in this invention offers synergistic barrier, passivation, and corrosion inhibition. Through the integrated design of film-forming resins and functional nanomaterials, it provides more durable protection in harsh environments, significantly improving the corrosion resistance and service life of metal substrates.

Description

Technical Field

[0001] The present invention belongs to the technical field of heavy-duty anti-corrosion coating preparation, and in particular relates to an epoxy composite coating with synergistic barrier, passivation and corrosion inhibition effects and a preparation method thereof. Background Art

[0002] Marine corrosion can cause damage and failure of marine engineering steel structures and has a serious impact on the marine ecosystem. Therefore, how to effectively prevent marine corrosion has become a major research topic both domestically and internationally. Applying organic coatings to surfaces is an effective and essential method for improving the corrosion resistance of marine engineering steel structures. However, due to solvent volatilization and improper curing methods, organic coatings are prone to developing defects such as micropores and microcracks during the curing process, which provide diffusion channels for corrosive media and ultimately lead to the failure of the coating's corrosion resistance.

[0003] The current main solution to the above problems is to add functional nanomaterials loaded with corrosion inhibitors to enhance the physical barrier function of the coating and give it active protective properties. However, the regulation of factors such as the dispersion of nanomaterials in the coating, compatibility with the resin, and the loading and release of corrosion inhibitors remain difficult problems that need to be solved. In addition, the film-forming resin is the main body of the organic coating. Its molecular structure and curing method will affect the internal structure of the coating, which in turn has a significant impact on the corrosion resistance of the coating. Therefore, starting from the design of both the film-forming resin and the functional nanomaterial, it is very necessary to comprehensively consider the passive protective effect of the film-forming resin and the active protective properties of the functional nanomaterial in order to construct a highly corrosion-resistant organic coating. Summary of the Invention

[0004] In view of this, the present invention aims to overcome the defects in the prior art and proposes an epoxy composite coating with synergistic barrier, passivation and corrosion inhibition effects and a preparation method thereof.

[0005] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0006] In the first aspect, the present invention provides an epoxy composite coating with synergistic effects of barrier, passivation and corrosion inhibition, the epoxy composite coating comprising RE 3+ @PANI@MXene composite nanoparticles and self-curing epoxy resin, wherein the RE 3+ @PANI@MXene composite nanoparticles composed of rare earth cations RE 3+ MXene nanosheets loaded on polyaniline in situ modified (PANI@MXene) were prepared.

[0007] Preferably, the rare earth cation RE 3+ For La 3+ 、Ce 3+ 、Pr 3+ 、Nd3+ 、Sm 3+ 、Eu 3+ 、Gd 3+ 、Y 3+ Any one or more of .

[0008] Preferably, the rare earth cation RE 3+ The mass ratio of PANI@MXene is (0.1~1):(5~10).

[0009] Preferably, the RE 3+ The mass ratio of @PANI@MXene nanoparticles to self-curing epoxy resin is (1~5):(100~200).

[0010] Preferably, the self-curing epoxy resin comprises 601 epoxy resin, organic titanium chelate and organic solvent, wherein the mass ratio of 601 epoxy resin to organic titanium chelate is 20:(1-10).

[0011] Preferably, the method for preparing the self-curing epoxy resin comprises the following steps:

[0012] The 601 epoxy resin and the organic solvent are mixed, and the organic titanium chelate is added in a water bath at a temperature of 30 to 90° C., and the mixture is stirred and reacted for 2 to 6 hours to prepare a self-curing epoxy resin.

[0013] More preferably, the organic solvent is a mixed solvent of xylene and isopropyl alcohol.

[0014] In a second aspect, the present invention further provides a method for preparing the above-mentioned epoxy composite coating having a synergistic effect of barrier, passivation and corrosion inhibition, comprising the following steps:

[0015] RE 3+ @PANI@MXene composite nanoparticles are dispersed in self-curing epoxy resin and stirred evenly to obtain a composite coating. The composite coating is coated on the surface of the substrate, and after standing and curing at 150-180°C for 2-4 hours, an epoxy composite coating with synergistic barrier, passivation and corrosion inhibition effects is obtained.

[0016] Preferably, the RE 3+ The preparation method of @PANI@MXene composite nanoparticles includes the following steps:

[0017] Adding polyaniline in situ modified MXene nanosheets (PANI@MXene) and rare earth cations RE into organic solvent 3+ , stirred at room temperature for 1 to 3 hours, then kept in a vacuum drying oven for 0.5 to 2 hours, and finally stirred at room temperature for 12 to 24 hours to obtain RE 3+ @PANI@MXene composite nanoparticles.

[0018] More preferably, the organic solvent is a mixed solvent of xylene and isopropyl alcohol.

[0019] Preferably, the preparation method of the polyaniline in situ modified MXene nanosheets (PANI@MXene) comprises the following steps:

[0020] MXene nanosheets and aniline were added to an HCl solution and ultrasonically mixed and dispersed in an ice-water bath. Then, an HCl solution of ammonium persulfate was added dropwise under stirring and a polymerization reaction was carried out in an ice-water bath. The mixture was filtered, washed, and dried to obtain polyaniline in situ modified MXene nanosheets (PANI@MXene).

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] (1) The present invention starts from the two aspects of film-forming resin and functional nanomaterial design. Through the comprehensive design of film-forming resin and functional nanomaterial, the coating can provide more lasting protection in harsh environments, significantly improving the corrosion resistance and service life of the metal substrate;

[0023] (2) The self-curing epoxy resin in the present invention is a single-component system, which can avoid the coating defects caused by the poor compatibility between components and the difficulty in accurately controlling the proportions of multi-component curing systems, and can significantly enhance the physical barrier properties of the coating;

[0024] (3) The two-dimensional nanomaterial (RE 3+ @PANI@MXene) facilitates the creation of a "maze effect" within the coating, extending the penetration path of the corrosive medium. The PANI on the surface of the two-dimensional nanomaterial and the loaded rare earth metal corrosion inhibitor have a passivating and corrosion-inhibiting effect. This is because the PANI molecules modified on the surface of the two-dimensional nanomaterial contain a large number of amino and imino groups. These groups can bind to the metal corrosion inhibitor through complexation and react with the epoxy groups in the self-curing epoxy resin. This chemically binds the two-dimensional nanoparticles and the resin matrix together, effectively preventing the agglomeration of the nanoparticles and the generation of internal defects in the coating. The result is an epoxy composite coating with a synergistic barrier, passivation, and corrosion inhibition effect, achieving long-lasting protection for metals in harsh environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 These are the Bode plots of epoxy resin composite coating A1, epoxy resin composite coating B1, epoxy resin composite coating B2, self-curing epoxy resin coating B3, two-component epoxy resin composite coating B4 and two-component epoxy resin coating B5 in 3.5wt% NaCl solution. DETAILED DESCRIPTION

[0026] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0027] Unless defined otherwise herein, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0028] Where values ​​are described herein as ranges, it should be understood that such disclosure includes disclosure of all possible sub-ranges within that range, as well as specific values ​​falling within that range, regardless of whether a specific value or sub-range is explicitly stated.

[0029] In this document, "a plurality of" and the like, unless otherwise specified, refer to a number greater than or equal to 2. For example, "one or more" means one or more than or equal to two.

[0030] In this document, the terms “preferably” and “more preferably” are only used to describe implementation methods or examples with better effects. It should be understood that they do not limit the scope of protection of the present invention.

[0031] In this document, the word "further" and the like are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of the present invention.

[0032] In this article, the term "and / or" is used to describe the association relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0033] As used herein, the term "about" means + / - 10%, preferably + / - 5%, more preferably + / - 1% of the specified value.

[0034] In this document, the terms “include,” “including,” “have,” “contain,” etc. are open-ended terms, meaning including but not limited to.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention.

[0036] The present invention will be described in detail below with reference to the embodiments.

[0037] Example 1

[0038] (1) Preparation of self-curing epoxy resin

[0039] 20 g of 601 epoxy resin (epoxy value 0.18 to 0.22) and 36.4 ml of a xylene / isopropanol (7 / 3) mixed solution were added to a round-bottom flask (equipped with a mechanical stirrer, a reflux device, a dropping channel, and a thermometer) to prepare a solution with a mass fraction of 55%. The round-bottom flask was placed in a constant temperature water area at 80°C, and then 2 g of an organic titanium chelate was added. The reaction was stirred for 2 hours to prepare a self-curing epoxy resin.

[0040] (2) Preparation of polyaniline in situ modified MXene nanosheets loaded with corrosion inhibitor

[0041] 5g of MXene nanosheets and 2.5g of aniline were added to a 250ml 1M HCl solution and sonicated in an ice-water bath for 0.5h. 250mL of a 1M HCl solution (6.25g) was then slowly added dropwise to the solution while stirring. The mixture was stirred in an ice-water bath for 5h. After the solution turned completely dark green, the reaction product was filtered to obtain the product. The product was washed three times with ultrapure water and three times with ethanol, and then dried in a 60°C oven for 24h to obtain polyaniline in situ modified MXene nanosheets (PANI@MXene).

[0042] PANI@MXene nanosheets were used as nanocontainers to load rare earth metal corrosion inhibitors through the mutual complexation between PANI and rare earth cations. 5g PANI@MXene nanosheets were added to 50mL of a 7 / 3 mixed solution of xylene / isopropanol, 1g of praseodymium nitrate (Pr(NO3)3) was added, stirred at room temperature for 1h, and then kept in a vacuum drying oven for 0.5h. Finally, stirred at room temperature for 2h to obtain the loaded Pr 3+ PANI@MXene composite nanoparticles as corrosion inhibitor (Pr 3+ @PANI@MXene).

[0043] (3) Preparation of epoxy composite coating with synergistic effect of barrier, passivation and corrosion inhibition

[0044] 0.5g Pr 3+ @PANI@MXene nanoparticles were dispersed in 10g of self-curing epoxy resin and stirred at room temperature for 0.5h. The mixture was brushed on the treated tinplate sheet, left at room temperature for 1 day, and then cured in an electric forced air drying oven at 160°C for 24h to obtain a 30μm thick epoxy resin composite coating A1 with synergistic barrier, passivation and corrosion inhibition effects.

[0045] Example 2

[0046] (1) Preparation of self-curing epoxy resin

[0047] 20 g of 601 epoxy resin (epoxy value 0.18 to 0.22) and 36.4 ml of a xylene / isopropanol (7 / 3) mixed solution were added to a round-bottom flask (equipped with a mechanical stirrer, a reflux device, a dropping channel, and a thermometer) to prepare a solution with a mass fraction of 55%. The round-bottom flask was placed in a constant temperature water area at 80°C, and then 1 g of an organic titanium chelate was added. The reaction was stirred for 2 hours to prepare a self-curing epoxy resin.

[0048] (2) Preparation of polyaniline in situ modified MXene nanosheets loaded with corrosion inhibitor

[0049] 5g of MXene nanosheets and 2.5g of aniline were added to a 250ml 1M HCl solution and sonicated in an ice-water bath for 0.5h. 250mL of a 1M HCl solution (6.25g) was then slowly added dropwise to the solution while stirring. The mixture was stirred in an ice-water bath for 5h. After the solution turned completely dark green, the reaction product was filtered to obtain the product. The product was washed three times with ultrapure water and three times with ethanol, and then dried in a 60°C oven for 24h to obtain polyaniline in situ modified MXene nanosheets (PANI@MXene).

[0050] PANI@MXene nanosheets were used as nanocontainers to load rare earth metal corrosion inhibitors through the mutual complexation between PANI and rare earth cations. 5g PANI@MXene nanosheets were added to 50mL of a 7 / 3 xylene / isopropanol mixed solution, and 0.05g of lanthanum nitrate (La(NO3)3) was added. The mixture was stirred at room temperature for 1h and then kept in a vacuum drying oven for 0.5h. Finally, the loaded La(NO3)3 was obtained by stirring at room temperature for 2h. 3+ PANI@MXene composite nanoparticles as corrosion inhibitor (La 3+ @PANI@MXene).

[0051] (3) Preparation of epoxy composite coating with synergistic effect of barrier, passivation and corrosion inhibition

[0052] 0.05g La 3+ @PANI@MXene nanoparticles were dispersed in 10g of self-curing epoxy resin and stirred at room temperature for 0.5h. The mixture was brushed on the treated tinplate sheet, left at room temperature for 1 day, and then cured at 160°C in an electric forced air drying oven for 24h to obtain a 30μm thick epoxy resin composite coating with synergistic barrier, passivation and corrosion inhibition effects.

[0053] Example 3

[0054] (1) Preparation of self-curing epoxy resin

[0055] 20 g of 601 epoxy resin (epoxy value 0.18 to 0.22) and 36.4 ml of a xylene / isopropanol (7 / 3) mixed solution were added to a round-bottom flask (equipped with a mechanical stirrer, a reflux device, a dropping channel, and a thermometer) to prepare a solution with a mass fraction of 55%. The round-bottom flask was placed in a constant temperature water area at 80°C, and then 5 g of an organic titanium chelate was added. The reaction was stirred for 2 hours to prepare a self-curing epoxy resin.

[0056] (2) Preparation of polyaniline in situ modified MXene nanosheets loaded with corrosion inhibitor

[0057] 5g of MXene nanosheets and 2.5g of aniline were added to a 250ml 1M HCl solution and sonicated in an ice-water bath for 0.5h. 250mL of a 1M HCl solution (6.25g) was then slowly added dropwise to the solution while stirring. The mixture was stirred in an ice-water bath for 5h. After the solution turned completely dark green, the reaction product was filtered to obtain the product. The product was washed three times with ultrapure water and three times with ethanol, and then dried in a 60°C oven for 24h to obtain polyaniline in situ modified MXene nanosheets (PANI@MXene).

[0058] PANI@MXene nanosheets were used as nanocontainers to load rare earth metal corrosion inhibitors through the mutual complexation between PANI and rare earth cations. 5g of PANI@MXene nanosheets were added to 50mL of a 7 / 3 mixture of xylene and isopropanol, and 0.5g of gadolinium nitrate (Gd(NO3)3) was added. The mixture was stirred at room temperature for 1h, and then kept in a vacuum drying oven for 0.5h. Finally, the Gd(NO3)3 was loaded by stirring at room temperature for 2h. 3+ PANI@MXene composite nanoparticles (Gd 3+ @PANI@MXene).

[0059] (3) Preparation of epoxy composite coating with synergistic effect of barrier, passivation and corrosion inhibition

[0060] 0.3 g Gd 3+ @PANI@MXene nanoparticles were dispersed in 10g of self-curing epoxy resin and stirred at room temperature for 0.5h. The mixture was brushed on the treated tinplate sheet, left at room temperature for 1 day, and then cured at 160°C in an electric forced air drying oven for 24h to obtain a 30μm thick epoxy resin composite coating with synergistic barrier, passivation and corrosion inhibition effects.

[0061] Example 4

[0062] (1) Preparation of self-curing epoxy resin

[0063] 20 g of 601 epoxy resin (epoxy value 0.18 to 0.22) and 36.4 ml of a xylene / isopropanol (7 / 3) mixed solution were added to a round-bottom flask (equipped with a mechanical stirrer, a reflux device, a dropping channel, and a thermometer) to prepare a solution with a mass fraction of 55%. The round-bottom flask was placed in a constant temperature water area at 80°C, and then 10 g of an organic titanium chelate was added. The reaction was stirred for 2 hours to prepare a self-curing epoxy resin.

[0064] (2) Preparation of polyaniline in situ modified MXene nanosheets loaded with corrosion inhibitor

[0065] 5g of MXene nanosheets and 2.5g of aniline were added to a 250ml 1M HCl solution and sonicated in an ice-water bath for 0.5h. 250mL of a 1M HCl solution (6.25g) was then slowly added dropwise to the solution while stirring. The mixture was stirred in an ice-water bath for 5h. After the solution turned completely dark green, the reaction product was filtered to obtain the product. The product was washed three times with ultrapure water and three times with ethanol, and then dried in a 60°C oven for 24h to obtain polyaniline in situ modified MXene nanosheets (PANI@MXene).

[0066] PANI@MXene nanosheets were used as nanocontainers to load rare earth metal corrosion inhibitors through the mutual complexation between PANI and rare earth cations. 5g PANI@MXene nanosheets were added to 50mL of a 7 / 3 xylene / isopropanol mixed solution, and 0.25g of yttrium nitrate (Y(NO3)3) was added. The mixture was stirred at room temperature for 1h and then kept in a vacuum drying oven for 0.5h. Finally, the loaded Y(NO3)3 was obtained by stirring at room temperature for 2h. 3+ PANI@MXene composite nanoparticles as corrosion inhibitor (Y 3+ @PANI@MXene).

[0067] (3) Preparation of epoxy composite coating with synergistic effect of barrier, passivation and corrosion inhibition

[0068] 0.5g Y 3+ @PANI@MXene nanoparticles were dispersed in 10g of self-curing epoxy resin and stirred at room temperature for 0.5h. The mixture was brushed on the treated tinplate sheet, left at room temperature for 1 day, and then cured at 160°C in an electric forced air drying oven for 24h to obtain a 30μm thick epoxy resin composite coating with synergistic barrier, passivation and corrosion inhibition effects.

[0069] Comparative Example 1

[0070] (1) Preparation of self-curing epoxy resin

[0071] The preparation method of the self-curing epoxy resin is the same as that in Example 1.

[0072] (2) Preparation of MXene nanosheets loaded with corrosion inhibitors

[0073] In this comparative example, MXene nanosheets were not modified with polyaniline in situ, but were directly used as nanocontainers for loading corrosion inhibitors. The specific steps were as follows: 5 g of MXene nanosheets were added to 50 mL of a 7 / 3 xylene / isopropanol mixed solution, 1 g of praseodymium nitrate (Pr(NO3)3) was added, stirred at room temperature for 1 h, and then kept in a vacuum drying oven for 0.5 h. Finally, stirred at room temperature for 24 h to obtain a loaded Pr 3+ MXene composite nanoparticles as corrosion inhibitor (Pr 3+ @MXene).

[0074] (3) Preparation of epoxy resin composite coating B1

[0075] 0.5g Pr 3+ @MXene nanoparticles were dispersed in 10 g of self-curing epoxy resin and stirred at room temperature for 0.5 h. The mixture was then brushed onto the treated tinplate sheet, left at room temperature for 1 day, and then cured in an electric forced air drying oven at 160°C for 24 h to obtain an epoxy resin composite coating B1 with a thickness of 30 μm.

[0076] Comparative Example 2

[0077] (1) Preparation of self-curing epoxy resin

[0078] The preparation method of the self-curing epoxy resin is the same as that in Example 1.

[0079] (2) Preparation of polyaniline in situ modified MXene nanosheets

[0080] 5g of MXene nanosheets and 2.5g of aniline were added to a 250ml 1M HCl solution and sonicated in an ice-water bath for 0.5h. 250mL of a 1M HCl solution (6.25g) was then slowly added dropwise to the solution while stirring. The mixture was stirred in an ice-water bath for 5h. After the solution turned completely dark green, the reaction product was filtered to obtain the product. The product was washed three times with ultrapure water and three times with ethanol, and then dried in a 60°C oven for 24h to obtain polyaniline in situ modified MXene nanosheets (PANI@MXene).

[0081] (3) Preparation of epoxy resin composite coating B2

[0082] 0.5 g of PANI@MXene nanoparticles were dispersed in 10 g of self-curing epoxy resin and stirred at room temperature for 0.5 h. The mixture was brushed on the treated tinplate sheet and left at room temperature for 1 day. It was then cured in an electric forced air drying oven at 160 ° C for 24 h to obtain an epoxy resin composite coating B2 with a thickness of 30 μm.

[0083] Comparative Example 3

[0084] (1) Preparation of self-curing epoxy resin

[0085] The preparation method of the self-curing epoxy resin is the same as that in Example 1.

[0086] (2) Preparation of self-curing epoxy resin coating B3

[0087] The self-curing epoxy resin was brush-coated on the treated tinplate sheet, left at room temperature for 1 day, and then cured in an electric blast drying oven at 160° C. for 24 h to obtain a self-curing epoxy resin coating B3 with a thickness of 30 μm.

[0088] Comparative Example 4

[0089] (1) Preparation of two-component epoxy resin

[0090] Add 20g of 601 epoxy resin and 36.4ml of a 7 / 3 xylene / isopropyl alcohol mixture to a round-bottom flask and stir at room temperature for 0.5h to a 55% solution. Then, add 4g of epoxy polyamide curing agent 650 and stir for 0.5h to prepare a two-component epoxy resin.

[0091] (2) Preparation of polyaniline in situ modified MXene nanosheets loaded with corrosion inhibitor

[0092] The preparation method of the corrosion inhibitor-loaded polyaniline in situ modified MXene nanosheets is the same as that in Example 1.

[0093] (3) Preparation of two-component epoxy resin composite coating B4

[0094] 0.5g Pr 3+ @PANI@MXene nanoparticles were dispersed in 10 g of two-component epoxy resin and stirred at room temperature for 0.5 h. The mixture was brushed on the treated tinplate sheet, left at room temperature for 1 day, and then cured in an electric forced air drying oven at 160°C for 24 h to obtain a two-component epoxy resin composite coating B4 with a thickness of 30 μm.

[0095] Comparative Example 5

[0096] (1) Preparation of two-component epoxy resin

[0097] Add 20g of 601 epoxy resin and 36.4ml of a 7 / 3 xylene / isopropyl alcohol mixture to a round-bottom flask and stir at room temperature for 0.5h to a 55% solution. Then, add 4g of epoxy polyamide curing agent 650 and stir for 0.5h to prepare a two-component epoxy resin.

[0098] (2) Preparation of two-component epoxy resin coating B5

[0099] The two-component epoxy resin was brush-coated on the treated tinplate sheet, left at room temperature for 1 day, and then cured in an electric blast drying oven at 160° C. for 24 hours to obtain a two-component epoxy resin coating B5 with a thickness of 30 μm.

[0100] Electrochemical impedance spectroscopy (EIS) technology was used to characterize the anti-corrosion performance of the coating. Figure 1 Bode plots of epoxy resin composite coating A1, epoxy resin composite coating B1, epoxy resin composite coating B2, self-curing epoxy resin coating B3, two-component epoxy resin composite coating B4 and two-component epoxy resin coating B5 in 3.5wt% NaCl solution. The lowest frequency (Z f＝0.01Hz ) can be used as a semi-quantitative indicator of the barrier performance of the coating.

[0101] like Figure 1 As shown in the figure, the epoxy resin composite coating A1 with synergistic barrier, passivation and corrosion inhibition prepared in Example 1 has excellent anti-corrosion performance. f＝0.01Hz About 1.8×10 9 Ω·cm 2 , which is higher than all the comparative examples, especially higher than the Z of the two-component epoxy resin composite coating (B4) and the two-component epoxy resin coating (B5). f＝0.01Hz It is two orders of magnitude higher, which is mainly because the single-component self-curing epoxy resin does not require a curing agent during curing, which can avoid the coating defect problem caused by poor component compatibility and difficult to accurately control the proportion of the traditional two-component system, forming a uniform and dense coating, so that the coating has excellent physical barrier properties. In the two-component epoxy resin coating system, due to the volatilization of the solvent and the unreasonable curing method, many defects such as micropores and microcracks are easily generated during the curing process, thereby providing diffusion channels for the corrosive medium, and ultimately leading to the failure of the coating's anti-corrosion performance. It is worth noting that in the epoxy resin composite coating (B1) of comparative example 1, the MXene nanosheets are not in situ modified with polyaniline, the MXene nanosheets in the epoxy resin composite coating (B2) of comparative example 2 are in situ modified with polyaniline but not loaded with corrosion inhibitor, and the MXene nanosheets in situ modified with polyaniline in comparative example 3 self-curing epoxy resin coating (B3) do not contain loaded corrosion inhibitors. The Z values ​​of coatings B1, B2, and B3 are as follows: f＝0.01Hz The values ​​are all lower than those of coating A1, which means that the corrosion resistance of coating A1 is better than that of coatings B1, B2, and B3.

[0102] Table 1 Tafel polarization curve parameters of coatings

[0103]

[0104] The corrosion protection efficiency of the coating can be characterized by the Tafel polarization curve test. Table 1 shows the Tafel polarization curve parameters of the coating. Generally speaking, the lower the corrosion current density (i corr ) means that the coating has better anti-corrosion performance. As can be seen from Table 1, the epoxy resin composite coating A1 with synergistic effect of barrier, passivation and corrosion inhibition prepared in Example 1 has an i corr The value is significantly lower than that of the comparative coating. The Tafel results are consistent with the EIS characterization results, indicating that the coating of Example 1 has excellent corrosion protection and a lower corrosion rate. Therefore, the physical barrier effect of the self-curing epoxy resin and the passivation and corrosion inhibition effect of polyaniline (PANI) and rare earth metal corrosion inhibitors significantly improve the corrosion resistance of the coating, achieving high-performance and long-term corrosion protection of the coating.

[0105] 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 in the scope of protection of the present invention.

Claims

1. An epoxy composite coating with synergistic barrier, passivation and corrosion inhibition, characterized by: The epoxy composite coating includes RE 3+ @PANI@MXene composite nanoparticles and self-curing epoxy resin, wherein the RE 3+ @PANI@MXene composite nanoparticles composed of rare earth cations RE 3+ Prepared by in-situ modified MXene nanosheets loaded on polyaniline; The rare earth cation RE 3+ For La 3+ 、Ce 3+ 、Pr 3+ 、Nd 3+ 、Sm 3+ 、Eu 3+ 、Gd 3+ 、Y 3+ Any one or more of the following; The rare earth cation RE 3+ The mass ratio of PANI@MXene is (0.1~1):(5~10); The RE 3+ The mass ratio of @PANI@MXene nanoparticles to self-curing epoxy resin is (1-5): (100-200); The self-curing epoxy resin comprises 601 epoxy resin, organic titanium chelate and organic solvent, wherein the mass ratio of 601 epoxy resin to organic titanium chelate is 20: (1-10); The preparation method of the self-curing epoxy resin comprises the following steps: 601 epoxy resin and an organic solvent are mixed, and an organic titanium chelate is added in a water bath at a temperature of 30-90° C., and the mixture is stirred and reacted for 2-6 hours to prepare a self-curing epoxy resin.

2. The epoxy composite coating with synergistic barrier, passivation and corrosion inhibition according to claim 1, characterized in that: The organic solvent is a mixed solvent of xylene and isopropyl alcohol.

3. The method for preparing the epoxy composite coating with synergistic barrier, passivation and corrosion inhibition according to claim 1 or 2, characterized in that: The steps include: RE 3+ @PANI@MXene composite nanoparticles are dispersed in self-curing epoxy resin and stirred evenly to obtain a composite coating. The composite coating is applied to the surface of the substrate, and after standing and curing at 150-180°C for 2-4 hours, an epoxy composite coating with synergistic barrier, passivation and corrosion inhibition effects is obtained.

4. The method for preparing the epoxy composite coating with synergistic barrier, passivation and corrosion inhibition according to claim 3, characterized in that: The RE 3+ The preparation method of @PANI@MXene composite nanoparticles includes the following steps: Adding polyaniline in situ modified MXene nanosheets and rare earth cations RE to organic solvents 3+ , stirred at room temperature for 1~3h, then kept in a vacuum drying oven for 0.5~2h, and finally stirred at room temperature for 12~24h to obtain RE 3+ @PANI@MXene composite nanoparticles.

5. The method for preparing the epoxy composite coating with synergistic barrier, passivation and corrosion inhibition according to claim 3, characterized in that: The preparation method of the polyaniline in situ modified MXene nanosheets comprises the following steps: MXene nanosheets and aniline were added to HCl solution and dispersed by ultrasonic mixing in an ice-water bath; Then, an HCl solution of ammonium persulfate was added dropwise under stirring, and a polymerization reaction was carried out in an ice-water bath. The MXene nanosheets modified with polyaniline in situ were obtained by filtration, washing, and drying.

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