Chloride ion permeation inhibition composite anticorrosive coating as well as preparation method and application thereof

Abstract

The invention relates to a chloride ion permeation inhibition composite anticorrosive coating as well as a preparation method and application thereof. The chloride ion permeation inhibition composite anti-corrosion coating comprises a base material layer, at least one anti-corrosion bottom layer, at least one chloride ion permeation inhibition layer and an anti-corrosion surface layer which are sequentially arranged from bottom to top. The invention aims to solve the problem that a compact chloride ion permeation inhibition layer is formed on the surface of a resin coating through an interfacial polymerization method or a commercial reverse osmosis membrane is compounded into the coating so as to block the permeation of corrosive ions.

Description

Technical Field

[0001] This invention relates to the field of anti-corrosion materials technology, and in particular to a chloride ion penetration inhibiting composite anti-corrosion coating, its preparation method, and its application. Background Technology

[0002] Marine corrosion accelerates the deterioration of marine engineering structures, shortens their service life, and induces economic losses, safety risks, and ecological damage, severely restricting marine resource development and engineering sustainability. Compared to terrestrial environments, the higher salt concentration in marine environments poses a significant challenge to metal corrosion protection. Chloride ions in seawater affect the conductivity of the electrolyte film on steel, increase the solubility of corrosion products, and lead to the destruction of the passivation film. Organic coatings have attracted attention due to their low cost, ease of application, and robust mechanical properties, becoming one of the most widely used technologies. However, organic coatings are prone to developing micropores and cracks during curing and use, which accelerates the penetration of corrosive ions into the substrate and causes corrosion reactions in a short period.

[0003] To improve the corrosion resistance of materials, researchers have proposed two approaches to improve organic coatings. One is the "maze effect," which involves introducing nanofillers such as mica, montmorillonite, graphene, and their derivatives into the organic coating to extend the penetration path of corrosive ions, thereby enhancing the coating's corrosion resistance. The other is a superhydrophobic surface design based on the "lotus effect" found in nature, which effectively captures air and forms a stable gas film at the coating / solution interface, effectively physically blocking corrosive ions such as Cl- from direct contact with the metal substrate. While these technologies have shown some improvement in corrosion resistance, they suffer from problems such as high raw material costs, difficulty in dispersion, and complex processing techniques. A low-cost, high-corrosion-resistance coating remains a pursuit for researchers and industry. Summary of the Invention

[0004] In view of this, the main objective of this invention is to provide a chloride ion penetration-inhibiting composite anti-corrosion coating, its preparation method, and its application. This coating can effectively inhibit the penetration of corrosive ions such as chloride ions into the surface of substrates such as metals, not only effectively improving the anti-corrosion performance of the coating, but also being low in cost and not affecting the mechanical properties of the coating.

[0005] The objective of this invention and the technical problem it solves are achieved by the following technical solution. This invention proposes a chloride ion penetration inhibiting composite anti-corrosion coating, which comprises, from bottom to top, a substrate, at least one anti-corrosion underlayer, at least one chloride ion penetration inhibiting layer, and an anti-corrosion surface layer.

[0006] The objectives of this invention and the technical problems it addresses can be further achieved by the following technical measures.

[0007] Preferably, in the aforementioned chloride ion penetration inhibiting composite anti-corrosion coating, at least two layers of the anti-corrosion underlayer and at least two layers of chloride ion penetration inhibiting layer are alternately arranged.

[0008] Preferably, in the aforementioned chloride ion penetration-inhibiting composite anti-corrosion coating, the substrate is selected from Q235 steel, alloys, and reinforced concrete structures.

[0009] Preferably, in the aforementioned chloride ion penetration inhibiting composite anti-corrosion coating, the thickness of at least one layer of the anti-corrosion underlayer is 40μm to 80μm; the thickness of at least one layer of the chloride ion penetration inhibiting layer is 100nm to 300nm; and the thickness of the anti-corrosion surface layer is 40μm to 80μm.

[0010] The objective of this invention and the technical problem it solves are achieved by the following technical solution. This invention proposes a method for preparing a chloride ion permeation inhibiting composite anti-corrosion coating, comprising the preparation of at least one anti-corrosion underlayer, the preparation of at least one chloride ion permeation inhibiting layer, and the preparation of an anti-corrosion surface layer; wherein, the preparation of the at least one chloride ion permeation inhibiting layer includes preparing a polyamide-based chloride ion permeation inhibiting layer on a resin surface via interfacial polymerization; or directly using a commercially available reverse osmosis membrane to composite the chloride ion permeation inhibiting layer.

[0011] The objectives of this invention and the technical problems it addresses can be further achieved by the following technical measures.

[0012] Preferably, the aforementioned method for preparing the chloride ion penetration-inhibiting composite anti-corrosion coating may include the following steps:

[0013] 1) Mix the resin, curing agent, leveling agent, rheology modifier and defoamer in proportion to obtain an anti-corrosion base coat; apply the obtained anti-corrosion base coat to the surface of the treated substrate, and after complete curing, obtain the anti-corrosion base coat.

[0014] 2) First, add aqueous monomer, camphor sulfonic acid, triethylamine and sodium dodecyl sulfate to water in sequence and stir until homogeneous to obtain an aqueous solution. Then, add oil monomer to oil solvent and stir until homogeneous to obtain an oil solution. Finally, pour the aqueous solution evenly onto the anti-corrosion substrate obtained in step 1) and let it stand for 2-7 minutes. Remove excess solution from the surface by air purging. Then, pour the oil solution evenly onto the anti-corrosion substrate with excess solution removed and let it stand for 1-4 minutes. Dry it at 50-90 degrees Celsius for 3-8 minutes to obtain a chloride ion penetration inhibition layer.

[0015] 3) Mix the resin, curing agent, leveling agent, rheology modifier and defoamer in proportion to obtain the anti-corrosion base coating; apply the obtained anti-corrosion base coating to the chloride ion penetration inhibition layer obtained in step 2), and after complete curing, obtain the anti-corrosion surface layer, that is, obtain the chloride ion penetration inhibition composite anti-corrosion coating.

[0016] Preferably, the aforementioned method for preparing the chloride ion penetration inhibiting composite anti-corrosion coating further includes alternating and repeating steps 1) and 2), such that at least two layers of the anti-corrosion underlayer and at least two layers of chloride ion penetration inhibiting layer are alternately arranged.

[0017] Preferably, in the aforementioned method for preparing the chloride ion penetration-inhibiting composite anti-corrosion coating, in steps 1) and 3), the resin is selected from at least one of polyurethane resin, fluorocarbon resin, epoxy resin, and acrylic resin.

[0018] Preferably, in the aforementioned method for preparing the chloride ion penetration-inhibiting composite anti-corrosion coating, in steps 1) and 3), the mass fractions of the resin, curing agent, leveling agent, rheology modifier, and defoamer, based on the total mass of the resin, curing agent, leveling agent, rheology modifier, and defoamer, are 50%-70%, 20%-40%, 0.5%-2%, 0.5%-2%, 0.5%-2%, and 0.5%-2%, respectively.

[0019] Preferably, in the aforementioned method for preparing the chloride ion penetration-inhibiting composite anti-corrosion coating, in step 2), the aqueous monomer is selected from at least one of piperazine, dopamine, ethylenediamine, diethylenetriamine, and m-phenylenediamine.

[0020] Preferably, in the aforementioned method for preparing the chloride ion penetration-inhibiting composite anti-corrosion coating, in step 2), the mass fractions of the aqueous monomer, camphor sulfonic acid, triethylamine, and sodium dodecyl sulfate are 1%-3%, 2%-5%, 1%-3%, and 0.2%-0.4%, respectively.

[0021] Preferably, in the aforementioned method for preparing the chloride ion penetration-inhibiting composite anti-corrosion coating, in step 2), the oil phase monomer is selected from at least one of 2,4,4,6-biphenyltetramethyl chloride, terephthaloyl chloride, isophthaloyl chloride, and pyromellitic acid trimethyl chloride.

[0022] Preferably, in the aforementioned method for preparing the chloride ion penetration-inhibiting composite anti-corrosion coating, in step 2), the oil phase solvent is selected from at least one of n-hexane, cyclohexane, isopentane, and cycloheptane.

[0023] Preferably, in the aforementioned method for preparing the chloride ion penetration inhibiting composite anti-corrosion coating, in step 1), the substrate is a metal substrate, and the substrate is treated as follows: the surface of the substrate is sanded with sandpaper until the surface is flat; then the surface of the sanded substrate is cleaned with deionized water to remove impurities adsorbed on the surface; after cleaning, the substrate is dried.

[0024] Preferably, in the aforementioned method for preparing the chloride ion penetration inhibiting composite anti-corrosion coating, in step 1), the substrate is concrete, and the substrate is treated by: washing with water to remove impurities adsorbed on the substrate surface, wiping dry, and applying a sealing undercoat to the substrate surface.

[0025] Preferably, the aforementioned method for preparing the chloride ion penetration-inhibiting composite anti-corrosion coating may further include the following steps:

[0026] 1) Mix the resin, curing agent, leveling agent, rheology modifier and defoamer in proportion to obtain the anti-corrosion base coat; apply the obtained anti-corrosion base coat to the surface of the treated substrate, cure for 3-7 minutes to obtain the anti-corrosion pre-cured coating, press the commercial reverse osmosis membrane onto the anti-corrosion pre-cured coating, and then cure completely to obtain the anti-corrosion base coat and chloride ion permeation inhibition layer in sequence.

[0027] 2) Mix the resin, curing agent, leveling agent, rheology modifier and defoamer in proportion to obtain an anti-corrosion surface coating; apply the obtained anti-corrosion surface coating on the chloride ion penetration inhibition layer to obtain an anti-corrosion surface layer, that is, the chloride ion penetration inhibition composite anti-corrosion coating.

[0028] Preferably, the aforementioned method for preparing the chloride ion penetration inhibiting composite anti-corrosion coating further includes alternatingly repeating the preparation of the anti-corrosion underlayer and the chloride ion penetration inhibiting layer in step 1), such that at least two layers of the anti-corrosion underlayer and at least two layers of the chloride ion penetration inhibiting layer are alternately arranged.

[0029] Preferably, in the aforementioned method for preparing the chloride ion penetration-inhibiting composite anti-corrosion coating, in steps 1) and 2), the resin is selected from at least one of polyurethane resin, fluorocarbon resin, epoxy resin, and acrylic resin.

[0030] Preferably, in the aforementioned method for preparing the chloride ion penetration-inhibiting composite anti-corrosion coating, in steps 1) and 2), the mass fractions of the resin, curing agent, leveling agent, rheology modifier, and defoamer, based on the total mass of the resin, curing agent, leveling agent, rheology modifier, and defoamer, are 50%-70%, 20%-40%, 0.5%-2%, 0.5%-2%, 0.5%-2%, and 0.5%-2%, respectively.

[0031] Preferably, in the aforementioned method for preparing the chloride ion penetration inhibiting composite anti-corrosion coating, in step 1), the substrate is a metal substrate, and the substrate is treated as follows: the surface of the substrate is sanded with sandpaper until the surface is flat; then the surface of the sanded substrate is cleaned with deionized water to remove impurities adsorbed on the surface; after cleaning, the substrate is dried.

[0032] Preferably, in the aforementioned method for preparing the chloride ion penetration inhibiting composite anti-corrosion coating, in step 1), the substrate is concrete, and the substrate is treated by: washing with water to remove impurities adsorbed on the substrate surface, wiping dry, and applying a sealing undercoat to the substrate surface.

[0033] The objective of this invention and the technical problem it solves are achieved through the following technical solution. This invention proposes the application of a chloride ion penetration-inhibiting composite anti-corrosion coating in anti-corrosion engineering, wherein the anti-corrosion engineering is the anti-corrosion treatment of steel or concrete in high-salinity water bodies; wherein the high-salinity water body is seawater.

[0034] By means of the above technical solution, the chloride ion penetration inhibiting composite anti-corrosion coating, its preparation method and application provided by the present invention have at least the following advantages:

[0035] To address the issue of micropores formed after resin coatings cure, this invention utilizes interfacial polymerization to form a chloride ion permeation inhibition layer in situ on the resin coating surface, or incorporates a commercial reverse osmosis membrane into the coating to form a chloride ion permeation inhibition layer. The prepared samples underwent a 30-day immersion corrosion test in a 3.5 wt% NaCl solution. EDS testing results showed that, compared to the blank coating without the chloride ion permeation inhibition layer, the chloride concentration on the substrate surface of the composite coating prepared by interfacial polymerization was reduced by 42.3%, while the composite coating incorporating the commercial reverse osmosis membrane reduced this concentration by 57.7%, confirming that both methods effectively inhibit the permeation of chloride ions into the substrate. Electrochemical impedance spectroscopy further indicated that the electrochemical impedance value of the composite coating prepared by interfacial polymerization was twice that of the blank coating, while the impedance value of the composite coating incorporating the commercial reverse osmosis membrane was five times that of the blank coating, indicating a significant improvement in the coating's corrosion resistance. Simultaneously, the introduction of the chloride ion permeation inhibition layer did not affect the coating's adhesion or other mechanical properties. In addition, at least two layers of chloride ion penetration inhibition layer can be introduced by alternating the preparation of coatings such as anti-corrosion base layer and chloride ion penetration inhibition layer, which can further improve the anti-corrosion performance of composite coating.

[0036] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below. Attached Figure Description

[0037] Figure 1 This is one of the cross-sectional schematic diagrams of the chloride ion penetration inhibiting composite coating according to some embodiments of the present invention;

[0038] Figure 2 This is a second cross-sectional schematic diagram of the chloride ion penetration inhibiting composite coating according to some embodiments of the present invention;

[0039] Figure 3 This is a schematic diagram comparing the corrosion prevention principles of Comparative Example 1 and Example 1.

[0040] Figure 4 (a) Surface SEM image of the chloride ion penetration inhibiting composite anti-corrosion coating prepared in Comparative Example 1, (b) Surface SEM image of the chloride ion penetration inhibiting composite anti-corrosion coating prepared in Example 1, (c) Cross-sectional SEM image of the chloride ion penetration inhibiting composite anti-corrosion coating prepared in Comparative Example 1, and (d) Cross-sectional SEM image of the chloride ion penetration inhibiting composite anti-corrosion coating prepared in Example 1.

[0041] Figure 5 Nyquist and Bode plots of the chloride ion penetration inhibiting composite anti-corrosion coatings prepared in Comparative Example 1, Example 1, Example 4 and Example 6 after immersion in 3.5 wt% sodium chloride solution for 30 days;

[0042] Figure 6 SEM images of the substrate surface of the chloride ion penetration inhibiting composite anti-corrosion coatings prepared in Comparative Example 1, Example 1, Example 4 and Example 6 after immersion in salt water for 30 days;

[0043] Figure 7 EDS images of the substrate surface of the chloride ion penetration inhibiting composite anti-corrosion coatings prepared in Comparative Example 1, Example 1, Example 4 and Example 6 after immersion in salt water for 30 days. Detailed Implementation

[0044] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following detailed description, in conjunction with preferred embodiments, details the specific implementation methods, structures, features, and effects of a chloride ion penetration-inhibiting composite anti-corrosion coating, its preparation method, and its application. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable manner.

[0045] Unless otherwise specified, all materials or reagents listed below are commercially available.

[0046] Some embodiments of the present invention provide a chloride ion penetration inhibiting composite anti-corrosion coating, comprising a substrate, at least one anti-corrosion underlayer, at least one chloride ion penetration inhibiting layer and an anti-corrosion surface layer arranged sequentially from bottom to top.

[0047] Furthermore, at least two of the aforementioned anti-corrosion underlayers and at least two chloride ion penetration inhibiting layers are alternately arranged, which can further improve the anti-corrosion performance of the composite coating.

[0048] In some alternative embodiments, such as Figure 1As shown, the chloride ion penetration inhibiting composite anti-corrosion coating may include a substrate 11, an anti-corrosion underlayer 12, a chloride ion penetration inhibiting layer 13, and an anti-corrosion surface layer 14 connected sequentially from bottom to top.

[0049] In some alternative embodiments, such as Figure 2 As shown, the chloride ion penetration inhibiting composite anti-corrosion coating includes a substrate 21, an anti-corrosion underlayer 22, a chloride ion penetration inhibiting layer 23, an anti-corrosion underlayer 22, a chloride ion penetration inhibiting layer 23, and an anti-corrosion surface layer 24 connected sequentially from bottom to top.

[0050] In some alternative embodiments, the substrate 11 may be selected from low-carbon steel Q235 steel, alloys such as aluminum alloys, and reinforced concrete structures.

[0051] In some optional embodiments, the thickness of the anti-corrosion underlayer 12 is 40μm to 80μm. The anti-corrosion underlayer 12 generally serves to ensure the adhesion between the coating and the substrate, and to prevent corrosion. The anti-corrosion ability of the coating is generally closely related to its thickness. Therefore, if the thickness is less than 40μm, the coating is too thin and its anti-corrosion ability will be greatly reduced, while if the thickness is greater than 80μm, the coating is too thick and will lead to increased costs. The thickness of the chloride ion permeation inhibition layer 13 is 100nm-300nm or is a commercial reverse osmosis membrane. The thickness of the chloride ion permeation inhibition layer is uncontrollable during the preparation process, and 100-300nm is its approximate thickness range. The addition of the chloride ion permeation inhibition layer does not increase the anti-corrosion ability of the coating due to the increase in thickness. The thickness of the anti-corrosion surface layer 14 is 40μm to 80μm. The anti-corrosion surface layer 14 generally serves the functions of weather resistance (such as resistance to ultraviolet radiation), wear resistance, and aesthetics, and therefore requires a certain thickness.

[0052] Some embodiments of the present invention also provide a method for preparing a chloride ion penetration inhibiting composite anti-corrosion coating, comprising the following steps:

[0053] Surface treatment of S1 substrate

[0054] When the substrate is a low-carbon steel, alloy, or other metallic material, the surface treatment process is as follows: The substrate surface is sanded with sandpaper until it is smooth; then, the sanded surface is cleaned with deionized water to remove impurities adsorbed on the surface; after cleaning, the substrate is dried to ensure no residual water droplets or other contaminants remain, and kept clean and dry for later use. This process effectively removes dust, oil, scale, rust, salt, and loose old paint film adhering to the surface of the metal substrate, ensuring good adhesion of subsequent coatings. For example, 80-grit, 200-grit, 400-grit, 1000-grit, and 2000-grit sandpaper can be used to remove contaminants from the surface of Q235 steel, followed by rinsing with deionized water and anhydrous ethanol, respectively.

[0055] When the supporting material is a reinforced concrete structure or other substrate, the surface treatment method is to wash with water to remove impurities adsorbed on the substrate surface, wipe it dry, apply epoxy resin to the substrate surface with a coating thickness of 30 micrometers, and keep it clean and dry after curing at room temperature. Reinforced concrete structures generally have cracks on their surfaces, so they are usually sealed with epoxy resin before applying the surface coating.

[0056] Preparation of S2 anti-corrosion base layer and chloride ion permeation inhibition layer

[0057] Preparation method 1: Mix resin, curing agent, leveling agent, rheology modifier and defoamer in proportion to obtain anti-corrosion base coating; apply the obtained anti-corrosion base coating to the surface of the substrate treated in step S1, and cure for 3-7 minutes to obtain anti-corrosion pre-cured coating; press the commercial reverse osmosis membrane tightly onto the obtained anti-corrosion pre-cured coating, and then cure completely to obtain an anti-corrosion base layer with a thickness of 40μm to 80μm and a chloride ion permeation inhibition layer with a thickness of 100nm to 300nm.

[0058] Preparation method 2: Mix resin, curing agent, leveling agent, rheology modifier and defoamer in proportion to obtain anti-corrosion base coating; apply the obtained anti-corrosion base coating to the surface of the substrate treated in step S1, and after complete curing, obtain an anti-corrosion base layer with a thickness of 40μm to 80μm; then prepare a polyamide separation layer on the surface of the resin coating by interfacial polymerization. First, prepare an aqueous phase solution by adding a certain amount of aqueous monomer, camphor sulfonic acid, triethylamine, and sodium dodecyl sulfate to water and stirring until homogeneous. Next, prepare an oil phase solution by adding a certain amount of oil phase monomer to the oil phase solvent and stirring until homogeneous. Finally, pour the aqueous phase solution evenly onto the anti-corrosion underlayer obtained in step S2 and let it stand for 2-7 minutes. Remove the surface solution by air purging. Pour the oil phase solution onto the anti-corrosion underlayer, let it stand for 1-4 minutes, and then dry it in an oven at 50-90 degrees Celsius for 3-8 minutes to obtain a chloride ion penetration inhibition layer with a thickness of 100nm-300nm. The anti-corrosion underlayer generally serves to ensure the adhesion between the coating and the substrate and provides corrosion protection.

[0059] The wetting process primarily involves immersing the aqueous monomers into the micropores of the coating surface. A time shorter than 2 minutes results in insufficient immersion, while a time longer than 7 minutes is wasteful. The post-treatment process mainly uses heat treatment to promote residual cross-linking reactions, thereby increasing the degree of cross-linking, removing material solvents, and stabilizing the membrane structure. Aqueous and oil-phase monomers require a certain reaction time; a time shorter than 1 minute leads to insufficient reaction, while a time longer than 4 minutes is wasteful. Similarly, a drying time shorter than 3 minutes results in incomplete solvent removal, while a time longer than 8 minutes can damage the chloride ion penetration inhibition layer.

[0060] Preparation of S4 anti-corrosion surface layer

[0061] Resin, curing agent, leveling agent, rheology modifier, and defoamer are mixed evenly in proportion to obtain an anti-corrosion surface coating. The obtained anti-corrosion surface coating is applied to a chloride ion penetration inhibition layer to obtain an anti-corrosion surface layer with a thickness of 40μm to 80μm. The anti-corrosion surface layer generally serves to resist weathering (such as resisting the impact of ultraviolet rays) and wear.

[0062] In some optional embodiments, the preparation of the anti-corrosion substrate and the chloride ion penetration inhibition layer in step S2 is further repeated alternately, such that at least two layers of the anti-corrosion substrate and at least two layers of the chloride ion penetration inhibition layer are alternately arranged. By introducing at least two layers of chloride ion penetration inhibition layer through the alternating preparation of coatings such as anti-corrosion substrates and chloride ion penetration inhibition layers, the anti-corrosion performance of the composite coating is further improved.

[0063] In some optional embodiments, in steps S2 and S4, the resin can be at least one of polyurethane resin, fluorocarbon resin, epoxy resin, and acrylic resin. These resins are all anti-corrosion resins, and the type of resin will affect the formation of the chloride ion inhibiting layer on its surface.

[0064] In some optional embodiments, in steps S2 and S4, the mass fractions of the resin, curing agent, leveling agent, rheology modifier, and defoamer, based on the total mass, are 50%-70%, 20%-40%, 0.5%-2%, 0.5%-2%, 0.5%-2%, and 0.5%-2%, respectively. Insufficient curing agent will result in insufficient cross-linking of the coating, affecting its anti-corrosion effect; excessive curing agent will shorten the curing time, affecting its use. Adding too much leveling agent will lead to incompatibility between the leveling agent and the epoxy resin system; adding too little will result in an uneven coating. Adding too much defoamer will cause compatibility problems, leading to a decrease in the physical properties of the coating; adding too little will prevent the effective elimination of bubbles, affecting the film-forming effect of the resin.

[0065] In some optional embodiments, in step S3, the aqueous monomer may be selected from at least one of piperazine, dopamine, ethylenediamine, diethylenetriamine, and m-phenylenediamine. The compactness of the final membrane can be precisely controlled by changing the reactivity and number of functional groups of the aqueous monomer, and by introducing specific chemical functional groups.

[0066] In some optional embodiments, in step S3, the mass fractions of the aqueous monomer, camphor sulfonic acid, triethylamine, and sodium dodecyl sulfate are 1%-3%, 2%-5%, 1%-3%, and 0.2%-0.4%, respectively. A chloride ion permeation inhibition layer prepared with an aqueous monomer to oil monomer ratio within a certain range is preferable. Camphor sulfonic acid acts as a pH adjuster; too much (e.g., greater than 5%) or too little (e.g., less than 2%) camphor sulfonic acid will lead to excessively high or low pH values, which are detrimental to the polymerization reaction. Triethylamine acts as an acid-binding agent, removing the byproduct hydrochloric acid and promoting interfacial polymerization. A small amount of triethylamine, mainly acting as an acid-binding agent, will result in incomplete hydrochloric acid removal and insufficient reaction; a large amount will lead to an increased pH value, which is detrimental to the reaction. Sodium dodecyl sulfate acts as a surfactant, adjusting the wettability of the aqueous solution.

[0067] In some optional embodiments, in step S3, the oil phase monomer may be selected from at least one of 2,4,4,6-biphenyltetramethyl chloride, terephthaloyl chloride, isophthaloyl chloride, and pyromellitic trimethyl chloride, and these different types of oil phase monomers may form different network structures.

[0068] In some alternative embodiments, in step S3, taking into account the surface tension and viscosity of the solution, the oil phase solvent may be selected from at least one of n-hexane, cyclohexane, isopentane, and cycloheptane.

[0069] Some embodiments of the present invention provide an application of a chloride ion penetration inhibiting composite anti-corrosion coating in anti-corrosion engineering.

[0070] In some alternative embodiments, the corrosion protection process is a corrosion protection treatment of steel or concrete in waters with high salinity.

[0071] In some alternative embodiments, the high-salinity water area is seawater. Steel generally corrodes rapidly in high-salinity environments, so anti-corrosion treatment is required before application. Steel can corrode in the presence of oxygen and water, but its corrosion is greatly accelerated in environments containing chloride ions. Therefore, it is necessary to prevent chloride ions from penetrating to the steel surface. The chloride ion penetration inhibiting composite anti-corrosion coating prepared in this invention can only prevent chloride ion penetration, so it is generally used in high-salinity environments or seawater.

[0072] In the above technical solutions, the present invention can form a dense film on the coating surface through interfacial polymerization or by adding a commercial reverse osmosis membrane to the coating to block the penetration of corrosive ions. The chloride ion penetration inhibiting composite anti-corrosion coating has excellent chloride ion penetration inhibiting and anti-corrosion performance, making it suitable for anti-corrosion engineering applications, especially for the anti-corrosion treatment of steel and concrete in high-salt waters such as seawater. By combining an epoxy coating with a chloride ion penetration inhibiting layer to prepare a composite coating, the interception effect of the chloride ion penetration inhibiting layer on chloride ions prolongs the time for chloride ions to penetrate through the coating micropores to the substrate, thereby improving the coating's anti-corrosion capability.

[0073] The specific embodiments of the present invention will be described in further detail below with reference to examples, but this should not be construed as a limitation on the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention still fall within the scope of protection of the present invention.

[0074] Unless otherwise specified, all materials and reagents mentioned below are commercially available products well known to those skilled in the art; unless otherwise specified, all methods described are methods known in the art. Unless otherwise defined, the technical or scientific terms used should have the ordinary meaning understood by those skilled in the art to which this invention pertains.

[0075] Example 1

[0076] This embodiment provides a method for preparing a chloride ion penetration-inhibiting composite anti-corrosion coating, including the following steps:

[0077] (1) Use sandpaper of 80 mesh, 200 mesh, 400 mesh, 1000 mesh and 2000 mesh to polish Q235 steel in sequence to remove contaminants from the surface of Q235 steel, and then rinse it with deionized water and anhydrous ethanol respectively.

[0078] (2) Epoxy resin, curing agent F0705, leveling agent 2020, rheology modifier 8w, and defoamer DU-966 are mixed in a mass fraction of 60%, 36%, 1%, 1%, 1%, 1%, and 1%, respectively. After stirring at room temperature for 5 minutes, the mixture is applied to the substrate and cured at 50°C for 24 hours to obtain an anti-corrosion underlayer with a thickness of 50 micrometers.

[0079] (3) Prepare an aqueous solution of m-phenylenediamine, camphor sulfonic acid, triethylamine and sodium dodecyl sulfate with a mass fraction of 2.5%, 1.8% camphor sulfonic acid, 1.1% triethylamine and 0.12% sodium dodecyl sulfate respectively. Then prepare a hexane solution of 0.15% pyromellitic chloride. Pour the obtained aqueous solution evenly into the anti-corrosion substrate obtained in step (2) and wet for 4 minutes. Remove the surface solution by blowing air. Pour the obtained hexane solution evenly into the anti-corrosion substrate. Let it stand for 1 minute and then put it into an oven at 70 degrees Celsius to dry for 5 minutes to obtain a chloride ion penetration inhibition layer with a thickness of 100nm-300nm.

[0080] (4) Mix epoxy resin, curing agent F0705, leveling agent 2020, rheology modifier 8w, and defoamer DU-966 in a mass fraction of 60%, 36%, 1%, 1%, 1%, and 1%, respectively. Stir at room temperature for 5 minutes and then coat the mixture onto the chloride ion penetration inhibition layer obtained in step (3). Cur the mixture at 50 degrees Celsius for 24 hours to obtain an anti-corrosion surface layer with a thickness of 50 micrometers. The chloride ion penetration inhibition composite anti-corrosion coating is thus obtained.

[0081] The aforementioned chloride ion penetration inhibiting composite anti-corrosion coating comprises, from bottom to top, a substrate 11, an anti-corrosion underlayer 12, a chloride ion penetration inhibiting layer 13, and an anti-corrosion surface layer 14, as shown in the figure. Figure 1 .

[0082] Example 2

[0083] This embodiment provides a method for preparing a chloride ion penetration-inhibiting composite anti-corrosion coating, including the following steps:

[0084] (1) Use sandpaper of 80 mesh, 200 mesh, 400 mesh, 1000 mesh and 2000 mesh to polish Q235 steel in sequence to remove contaminants from the surface of Q235 steel, and then rinse it with deionized water and anhydrous ethanol respectively.

[0085] (2) Epoxy resin, curing agent F0705, leveling agent 2020, rheology modifier 8w, and defoamer DU-966 are mixed in proportions of 60%, 36%, 1%, 1%, 1%, and 1% by mass, respectively. After stirring at room temperature for 5 minutes, the mixture is applied to the substrate and cured at 50°C for 24 hours to obtain an anti-corrosion underlayer with a thickness of 50 micrometers.

[0086] (3) Prepare an aqueous solution of m-phenylenediamine, camphor sulfonic acid, triethylamine and sodium dodecyl sulfate with a mass fraction of 2.5%, 1.8% camphor sulfonic acid, 1.1% triethylamine and 0.12% sodium dodecyl sulfate respectively. Then prepare a hexane solution of 2,4,4,6 biphenyltetrachlorohexane with a mass fraction of 0.15%. Pour the obtained aqueous solution evenly into the anti-corrosion substrate obtained in step (2) and wet it for 4 minutes. Remove the surface solution by blowing air. Pour the obtained hexane solution evenly into the anti-corrosion substrate. Let it stand for 1 minute and then put it into an oven at 70 degrees Celsius to dry for 5 minutes to obtain a chloride ion penetration inhibition layer with a thickness of 100nm-300nm.

[0087] (4) Mix epoxy resin, curing agent F0705, leveling agent 2020, rheology modifier 8w, and defoamer DU-966 in a mass fraction of 60%, 36%, 1%, 1%, 1%, and 1%, respectively. Stir at room temperature for 5 minutes and then coat the mixture onto the chloride ion penetration inhibition layer obtained in step (3). Cur the mixture at 50 degrees Celsius for 24 hours to obtain an anti-corrosion surface layer with a thickness of 50 micrometers. The chloride ion penetration inhibition composite anti-corrosion coating is thus obtained.

[0088] The aforementioned chloride ion penetration inhibiting composite anti-corrosion coating comprises, from bottom to top, a substrate 11, an anti-corrosion underlayer 12, a chloride ion penetration inhibiting layer 13, and an anti-corrosion surface layer 14, as shown in the figure. Figure 1 .

[0089] Example 3

[0090] This embodiment provides a method for preparing a chloride ion penetration-inhibiting composite anti-corrosion coating, including the following steps:

[0091] (1) Use sandpaper of 80 mesh, 200 mesh, 400 mesh, 1000 mesh and 2000 mesh to polish Q235 steel in sequence to remove contaminants from the surface of Q235 steel, and then rinse it with deionized water and anhydrous ethanol respectively.

[0092] (2) Epoxy resin, curing agent F0705, leveling agent 2020, rheology modifier 8w, and defoamer DU-966 are mixed in proportions of 60%, 36%, 1%, 1%, 1%, and 1% by mass, respectively. After stirring at room temperature for 5 minutes, the mixture is applied to the substrate and cured at 50°C for 24 hours to obtain an anti-corrosion underlayer with a thickness of 50 micrometers.

[0093] (3) Prepare an aqueous solution of diethylenetriamine, camphor sulfonic acid, triethylamine and sodium dodecyl sulfate with mass fractions of 2.5%, 1.8%, 1.1%, and 0.12%, respectively. Then prepare a hexane solution of pyromellitic chloride with a mass fraction of 0.15%. Pour the obtained aqueous solution evenly into the anti-corrosion substrate obtained in step (2) and wet it for 4 minutes. Remove the surface solution by blowing air. Pour the obtained hexane solution evenly into the anti-corrosion substrate. Let it stand for 1 minute and then put it into an oven at 70 degrees Celsius to dry for 5 minutes to obtain a chloride ion penetration inhibition layer with a thickness of 100nm-300nm.

[0094] (4) Mix epoxy resin, curing agent F0705, leveling agent 2020, rheology modifier 8w, and defoamer DU-966 in a mass fraction of 60%, 36%, 1%, 1%, 1%, and 1%, respectively. Stir at room temperature for 5 minutes and then coat the mixture onto the chloride ion penetration inhibition layer obtained in step (3). Cur the mixture at 50 degrees Celsius for 24 hours to obtain an anti-corrosion surface layer with a thickness of 50 micrometers. The chloride ion penetration inhibition composite anti-corrosion coating is thus obtained.

[0095] The aforementioned chloride ion penetration inhibiting composite anti-corrosion coating comprises, from bottom to top, a substrate 11, an anti-corrosion underlayer 12, a chloride ion penetration inhibiting layer 13, and an anti-corrosion surface layer 14, as shown in the figure. Figure 1 .

[0096] Example 4

[0097] This embodiment provides a method for preparing a chloride ion penetration-inhibiting composite anti-corrosion coating, including the following steps:

[0098] (1) Use sandpaper of 80 mesh, 200 mesh, 400 mesh, 1000 mesh and 2000 mesh to polish Q235 steel in sequence to remove contaminants from the surface of Q235 steel, and then rinse it with deionized water and anhydrous ethanol respectively.

[0099] (2) Epoxy resin, curing agent F0705, leveling agent 2020, rheology modifier 8w, and defoamer DU-966 are mixed in proportions of 60%, 36%, 1%, 1%, 1%, and 1% by mass, respectively. After stirring at room temperature for 5 minutes, the mixture is scraped onto the substrate and cured at 50°C for 5 minutes to obtain an anti-corrosion pre-cured coating. A commercial reverse osmosis membrane is then attached to the surface of the anti-corrosion pre-cured coating and cured at 50°C for 24 hours to obtain an anti-corrosion underlayer with a thickness of 50 micrometers and a chloride ion permeation inhibition layer with a thickness of 100nm-300nm.

[0100] (3) Mix epoxy resin, curing agent F0705, leveling agent 2020, rheology modifier 8w, and defoamer DU-966 in a mass fraction of 60%, 36%, 1%, 1%, 1%, and 1%, respectively. Stir at room temperature for 5 minutes and then coat the mixture onto the chloride ion penetration inhibition layer obtained in step (3). Cur the mixture at 50 degrees Celsius for 24 hours to obtain an anti-corrosion surface layer with a thickness of 50 micrometers. The chloride ion penetration inhibition composite anti-corrosion coating is thus obtained.

[0101] The aforementioned chloride ion penetration inhibiting composite anti-corrosion coating comprises, from bottom to top, a substrate 11, an anti-corrosion underlayer 12, a chloride ion penetration inhibiting layer 13, and an anti-corrosion surface layer 14, as shown in the figure. Figure 1 .

[0102] Example 5

[0103] This embodiment provides a method for preparing a chloride ion penetration-inhibiting composite anti-corrosion coating, including the following steps:

[0104] (1) Use sandpaper of 80 mesh, 200 mesh, 400 mesh, 1000 mesh and 2000 mesh to polish Q235 steel in sequence to remove contaminants from the surface of Q235 steel, and then rinse it with deionized water and anhydrous ethanol respectively.

[0105] (2) Epoxy resin, curing agent F0705, leveling agent 2020, rheology modifier 8w, and defoamer DU-966 are mixed in a mass fraction of 60%, 36%, 1%, 1%, 1%, 1%, and 1%, respectively. After stirring at room temperature for 5 minutes, the mixture is applied to the substrate and cured at 50°C for 24 hours to obtain an anti-corrosion underlayer with a thickness of 50 micrometers.

[0106] (3) Prepare an aqueous solution of m-phenylenediamine, camphor sulfonic acid, triethylamine and sodium dodecyl sulfate with mass fractions of 3%, 2.3%, 1.1%, and 0.12%, respectively. Then prepare a hexane solution of 0.20% trimesoyl chloride. Finally, in the anti-corrosion substrate, pour the obtained aqueous solution evenly into the anti-corrosion substrate obtained in step (2) and wet it for 4 minutes. Remove the surface solution by purging with nitrogen. Pour the obtained hexane solution evenly into the anti-corrosion substrate, let it stand for 1 minute, and then put it into a 70°C oven to dry for 5 minutes to obtain a chloride ion penetration inhibition layer with a thickness of 100nm-300nm.

[0107] (4) Mix epoxy resin, curing agent F0705, leveling agent 2020, rheology modifier 8w, and defoamer DU-966 in a mass fraction of 60%, 36%, 1%, 1%, 1%, 1%, and 1%, respectively. Stir at room temperature for 5 minutes and then apply the mixture to the chloride ion penetration inhibition layer obtained in step (3). Cur the mixture at 50 degrees Celsius for 24 hours to obtain an anti-corrosion surface layer with a thickness of 50 micrometers. The chloride ion penetration inhibition composite anti-corrosion coating is thus obtained.

[0108] The aforementioned chloride ion penetration inhibiting composite anti-corrosion coating comprises, from bottom to top, a substrate 11, an anti-corrosion underlayer 12, a chloride ion penetration inhibiting layer 13, and an anti-corrosion surface layer 14, as shown in the figure. Figure 1 .

[0109] Example 6

[0110] This embodiment provides a method for preparing a chloride ion penetration-inhibiting composite anti-corrosion coating, including the following steps:

[0111] (1) Use sandpaper of 80 mesh, 200 mesh, 400 mesh, 1000 mesh and 2000 mesh to polish Q235 steel in sequence to remove contaminants from the surface of Q235 steel, and then rinse it with deionized water and anhydrous ethanol respectively.

[0112] (2) Epoxy resin, curing agent F0705, leveling agent 2020, rheology modifier 8w, and defoamer DU-966 are mixed in a mass fraction of 60%, 36%, 1%, 1%, 1%, 1%, and 1%, respectively. After stirring at room temperature for 5 minutes, the mixture is applied to the substrate and cured at 50°C for 24 hours to obtain an anti-corrosion underlayer with a thickness of 25 micrometers.

[0113] (3) Prepare an aqueous solution of m-phenylenediamine, camphor sulfonic acid, triethylamine and sodium dodecyl sulfate with a mass fraction of 2.5%, 1.8% camphor sulfonic acid, 1.1% triethylamine and 0.12% sodium dodecyl sulfate respectively. Then prepare a hexane solution of 0.15% pyromellitic chloride. Pour the obtained aqueous solution evenly into the anti-corrosion substrate obtained in step (2) and wet for 4 minutes. Remove the surface solution by blowing air. Pour the obtained hexane solution evenly into the anti-corrosion substrate. Let it stand for 1 minute and then put it into an oven at 70 degrees Celsius to dry for 5 minutes to obtain a chloride ion penetration inhibition layer with a thickness of 50nm-150nm.

[0114] (4) Mix epoxy resin, curing agent F0705, leveling agent 2020, rheology modifier 8w, and defoamer DU-966 in a mass fraction of 60%, 36%, 1%, 1%, 1%, 1%, 1%, respectively. Stir at room temperature for 5 minutes, then apply the mixture to the substrate and cure at 50°C for 24 hours to obtain an anti-corrosion underlayer with a thickness of 25 micrometers.

[0115] (5) Prepare an aqueous solution of m-phenylenediamine, camphor sulfonic acid, triethylamine and sodium dodecyl sulfate with a mass fraction of 2.5%, 1.8% camphor sulfonic acid, 1.1% triethylamine and 0.12% sodium dodecyl sulfate respectively. Then prepare a hexane solution of 0.15% pyromellitic chloride. Pour the obtained aqueous solution evenly into the anti-corrosion substrate obtained in step (2) and wet for 4 minutes. Remove the surface solution by blowing air. Pour the obtained hexane solution evenly into the anti-corrosion substrate. Let it stand for 1 minute and then put it into an oven at 70 degrees Celsius to dry for 5 minutes to obtain a chloride ion penetration inhibition layer with a thickness of 50nm-150nm.

[0116] (6) Mix epoxy resin, curing agent F0705, leveling agent 2020, rheology modifier 8w, and defoamer DU-966 in a mass fraction of 60%, 36%, 1%, 1%, 1%, and 1%, respectively. Stir at room temperature for 5 minutes and then apply the mixture to the chloride ion penetration inhibition layer obtained in step (3). Cur the mixture at 50 degrees Celsius for 24 hours to obtain an anti-corrosion surface layer with a thickness of 50 micrometers. This will give you a chloride ion penetration inhibition composite anti-corrosion coating with two chloride ion penetration inhibition layers.

[0117] The aforementioned chloride ion penetration inhibiting composite anti-corrosion coating comprises, from bottom to top, a substrate 21, an anti-corrosion underlayer 22, a chloride ion penetration inhibiting layer 23, and an anti-corrosion surface layer 24, as shown in the figure. Figure 2 .

[0118] Example 7

[0119] This embodiment provides a method for preparing a chloride ion penetration-inhibiting composite anti-corrosion coating, including the following steps:

[0120] (1) Wash away the impurities adsorbed on the substrate surface with water. After cleaning, apply the sealing primer to the substrate surface and cure at room temperature for 48 hours. After curing, keep it clean and dry for later use.

[0121] (2) Epoxy resin, curing agent F0705, leveling agent 2020, rheology modifier 8w, and defoamer DU-966 are mixed in a mass fraction of 60%, 36%, 1%, 1%, 1%, and 1%, respectively. After stirring at room temperature for 5 minutes, the mixture is applied to the substrate and dried in an oven at 70 degrees Celsius for 5 hours and then dried at room temperature for 10 hours to obtain an anti-corrosion underlayer with a thickness of 50 micrometers.

[0122] (3) Prepare an aqueous solution of 3% m-phenylenediamine, 2.3% camphor sulfonic acid, 1.1% triethylamine, and 0.12% sodium dodecyl sulfate by mass, and then prepare a hexane solution of 0.15% trimesoyl chloride by mass. Pour the obtained aqueous solution evenly into the anti-corrosion substrate obtained in step (2) and wet it for 4 minutes. Remove the surface solution and pour the obtained hexane solution evenly into the anti-corrosion substrate. Let it stand for 1 minute and then put it into an oven at 70 degrees Celsius to dry for 6 minutes to obtain a chloride ion penetration inhibition layer with a thickness of 100nm-300nm.

[0123] (4) Mix epoxy resin, curing agent F0705, leveling agent 2020, rheology modifier 8w, and defoamer DU-966 in a mass fraction of 60%, 36%, 1%, 1%, 1%, and 1%, respectively. Stir at room temperature for 5 minutes and then coat the mixture onto the chloride ion penetration inhibition layer obtained in step (3). Dry the mixture in a 70°C oven for 5 hours and then at room temperature for 10 hours to obtain an anti-corrosion surface layer with a thickness of 50 micrometers. The chloride ion penetration inhibition composite anti-corrosion coating is thus obtained.

[0124] The aforementioned chloride ion penetration inhibiting composite anti-corrosion coating comprises, from bottom to top, a substrate 11, an anti-corrosion underlayer 12, a chloride ion penetration inhibiting layer 13, and an anti-corrosion surface layer 14, as shown in the figure. Figure 1 .

[0125] Comparative Example 1

[0126] The difference between this comparative example and Example 1 is that this comparative example does not include step (3).

[0127] Comparative Example 2

[0128] The difference between this comparative example and Example 6 is that this comparative example does not include step (3).

[0129] This invention reveals the anti-corrosion mechanism of composite coatings through material characterization and corrosion morphology analysis system.

[0130] like Figure 3 As shown, (a) is a schematic diagram of the corrosion prevention principle in Comparative Example 1; from this... Figure 3 As can be seen from the diagram, chloride ions can directly penetrate into Q235 steel along the "micropores" generated during the curing of the coating, thereby accelerating the corrosion of Q235 steel; (b) is a schematic diagram of the anti-corrosion principle of Example 1; when chloride ions penetrate along the "micropores" generated during the curing of the coating, most of the chloride ions will be blocked by the polyamide separation layer, delaying the penetration of chloride ions, thereby increasing the anti-corrosion ability of the coating.

[0131] like Figure 4As shown, (a) is a surface SEM image of the chloride ion penetration inhibiting composite anti-corrosion coating prepared in Comparative Example 1, and (c) is a cross-sectional SEM image of the chloride ion penetration inhibiting composite anti-corrosion coating prepared in Comparative Example 1. It can be seen from these images that there are a large number of "cracks" and "micropores" in the chloride ion penetration inhibiting composite anti-corrosion coating prepared in Comparative Example 1, which provide pathways for chloride ion penetration; (b) is a surface morphology image of the chloride ion penetration inhibiting composite anti-corrosion coating prepared in Example 1. It can be seen from this image that it exhibits a typical ridge and valley structure with no obvious cracks on the surface; (d) is a cross-sectional SEM image of the chloride ion penetration inhibiting composite anti-corrosion coating prepared in Example 1. It can be seen from this image that the chloride ion penetration inhibiting layer is very dense and has a thickness of only 113.4 nm.

[0132] like Figure 5 The image shows the impedance diagrams of the chloride ion penetration inhibiting composite anti-corrosion coatings prepared in Comparative Example 1, Example 1, Example 4, and Example 6 after immersion in a 3.5 wt% sodium chloride solution for 30 days; from this... Figure 5 It can be seen that after soaking for 30 days, the impedances of Examples 1, 4, and 6 are 2 times, 9 times, and 5 times that of Comparative Example 1, respectively. This indicates that adding a chloride ion penetration inhibition layer can improve the corrosion resistance of the coating, and the impedance increases with the number of chloride ion penetration inhibition layers added.

[0133] Figure 6 SEM images of Q235 steel surfaces after immersion in a 3.5 wt% sodium chloride solution for 30 days and removal of the chloride ion penetration-inhibiting composite anti-corrosion coating prepared in Comparative Example 1, Example 1, Example 4, and Example 6; from this... Figure 6 It can be seen that the steel surface of Comparative Example 1 (without chloride ion penetration layer) has a large amount of corrosion products, while that of Example 1 (containing one layer of chloride ion penetration inhibition layer) is relatively small, and that of Example 6 (containing two layers of chloride ion penetration inhibition layer) is even smaller, with only some black spots appearing. This indicates that adding multiple layers of chloride ion penetration inhibition layer can further improve the anti-corrosion ability of the coating.

[0134] Figure 7 EDS images of Q235 steel surfaces after immersion in a 3.5% sodium chloride solution for 30 days and removal of the chloride ion penetration-inhibiting composite anti-corrosion coatings prepared in Comparative Examples 1, 1, 4, and 6; from this... Figure 7 The chlorine content on the surface of Q235 steel after immersion indicates that the chloride ion penetration inhibition layer has a blocking effect on chloride ions, which can delay their arrival time in the substrate.

[0135] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0136] The numerical range described in this invention includes all values ​​within this range, and also includes any range value composed of any two values ​​within this range. Different values ​​of the same indicator appearing in all embodiments of this invention can be arbitrarily combined to form a range value.

[0137] The technical features in the claims and / or specification of this invention can be combined, and the combination is not limited to the combinations obtained through reference in the claims. Technical solutions obtained by combining the technical features in the claims and / or specification are also within the scope of protection of this invention.

[0138] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A chloride ion penetration-inhibiting composite anti-corrosion coating, characterized in that, The chloride ion penetration inhibiting composite anti-corrosion coating comprises, from bottom to top, a substrate, at least one anti-corrosion underlayer, at least one chloride ion penetration inhibiting layer, and one anti-corrosion surface layer.

2. The chloride ion penetration inhibiting composite anti-corrosion coating as described in claim 1, characterized in that, At least two layers of the anti-corrosion base layer and at least two layers of chloride ion penetration inhibition layer are alternately arranged.

3. The chloride ion penetration inhibiting composite anti-corrosion coating as described in claim 1, characterized in that, The substrate is selected from one of Q235 steel, alloy and reinforced concrete structure; the thickness of at least one layer of the anti-corrosion underlayer is 40μm to 80μm; the thickness of at least one layer of the chloride ion penetration inhibition layer is 100nm to 300nm; the thickness of the anti-corrosion surface layer is 40μm to 80μm.

4. A method for preparing a chloride ion penetration inhibiting composite anti-corrosion coating according to any one of claims 1-3, characterized in that, The preparation includes the preparation of at least one anti-corrosion underlayer, the preparation of at least one chloride ion permeation inhibition layer, and the preparation of an anti-corrosion surface layer; wherein, the preparation of at least one chloride ion permeation inhibition layer includes a polyamide chloride ion permeation inhibition layer prepared on the resin surface by interfacial polymerization; or a chloride ion permeation inhibition layer directly composed of a commercial reverse osmosis membrane.

5. The method for preparing the chloride ion penetration inhibiting composite anti-corrosion coating as described in claim 4, characterized in that, The method includes the following steps: 1) Mix the resin, curing agent, leveling agent, rheology modifier and defoamer in proportion to obtain an anti-corrosion base coat; apply the obtained anti-corrosion base coat to the surface of the treated substrate, and after complete curing, obtain the anti-corrosion base coat. 2) First, add aqueous monomer, camphor sulfonic acid, triethylamine and sodium dodecyl sulfate to water in sequence and stir until homogeneous to obtain an aqueous solution. Then, add oil monomer to oil solvent and stir until homogeneous to obtain an oil solution. Finally, pour the aqueous solution evenly onto the anti-corrosion substrate obtained in step 1) and let it stand for 2-7 minutes. Remove excess solution from the surface by air purging. Then, pour the oil solution evenly onto the anti-corrosion substrate with excess solution removed and let it stand for 1-4 minutes. Dry it at 50-90 degrees Celsius for 3-8 minutes to obtain a chloride ion penetration inhibition layer. 3) Mix the resin, curing agent, leveling agent, rheology modifier and defoamer in proportion to obtain an anti-corrosion surface coating; apply the obtained anti-corrosion surface coating to the chloride ion penetration inhibition layer obtained in step 2), and after complete curing, obtain the anti-corrosion surface layer, that is, the chloride ion penetration inhibition composite anti-corrosion coating.

6. The method for preparing the chloride ion penetration inhibiting composite anti-corrosion coating as described in claim 5, characterized in that, It also includes alternating and repeating steps 1) and 2), such that at least two layers of the anti-corrosion underlayer and at least two layers of chloride ion penetration inhibiting layer are alternately arranged; in steps 1) and 3), the resin is selected from at least one of polyurethane resin, fluorocarbon resin, epoxy resin and acrylic resin; based on the total mass of resin, curing agent, leveling agent, rheology modifier and defoamer, the mass fractions of the resin, curing agent, leveling agent, rheology modifier and defoamer are 50%-70%, 20%-40%, 0.5%-2%, 0.5%-2%, 0.5%-2% and 0.5%-2%, respectively.

7. The method for preparing the chloride ion penetration inhibiting composite anti-corrosion coating as described in claim 5, characterized in that, In step 2), the aqueous phase monomer is selected from at least one of piperazine, dopamine, ethylenediamine, diethylenetriamine, and m-phenylenediamine; the mass fractions of the aqueous phase monomer, camphor sulfonic acid, triethylamine, and sodium dodecyl sulfate are 1%-3%, 2%-5%, 1%-3%, and 0.2%-0.4%, respectively; the oil phase monomer is selected from at least one of 2,4,4,6-biphenyltetramethyl chloride, terephthaloyl chloride, isophthaloyl chloride, and trimesoyl pyromellitic acid; the oil phase solvent is selected from at least one of n-hexane, cyclohexane, isopentane, and cycloheptane; in step 1), the substrate is a metal substrate, and the substrate is treated by sanding the surface of the substrate with sandpaper until the surface is smooth; The surface of the polished substrate was then cleaned with deionized water to remove impurities adsorbed on the surface. After cleaning, wipe the substrate dry; or if the substrate is concrete, the substrate is treated by washing it with water to remove impurities adsorbed on the substrate surface, wiping it dry, and applying a sealing undercoat to the substrate surface.

8. The method for preparing the chloride ion penetration inhibiting composite anti-corrosion coating as described in claim 4, characterized in that, The method includes the following steps: 1) Mix the resin, curing agent, leveling agent, rheology modifier and defoamer in proportion to obtain the anti-corrosion base coat; apply the obtained anti-corrosion base coat to the surface of the treated substrate, cure for 3-7 minutes to obtain the anti-corrosion pre-cured coating, press the commercial reverse osmosis membrane onto the anti-corrosion pre-cured coating, and then cure completely to obtain the anti-corrosion base coat and chloride ion permeation inhibition layer in sequence. 2) Mix the resin, curing agent, leveling agent, rheology modifier and defoamer in proportion to obtain an anti-corrosion surface coating; apply the obtained anti-corrosion surface coating on the chloride ion penetration inhibition layer to obtain an anti-corrosion surface layer, that is, the chloride ion penetration inhibition composite anti-corrosion coating.

9. The method for preparing the chloride ion penetration inhibiting composite anti-corrosion coating as described in claim 8, characterized in that, The method also includes the alternating repeating of the preparation of the anti-corrosion substrate and the chloride ion penetration inhibition layer in step 1), such that at least two layers of the anti-corrosion substrate and at least two layers of the chloride ion penetration inhibition layer are alternately arranged; in steps 1) and 2), the resin is selected from at least one of polyurethane resin, fluorocarbon resin, epoxy resin and acrylic resin; based on the total mass of resin, curing agent, leveling agent, rheology modifier and defoamer, the mass fractions of the resin, curing agent, leveling agent, rheology modifier and defoamer are 50%-70%, 20%-40%, 0.5%-2%, 0.5%-2%, 0.5%-2% and 0.5%-2%, respectively; in step 1), the substrate is a metal substrate, and the substrate is treated by sanding the surface of the substrate with sandpaper until the surface is flat; The surface of the polished substrate was then cleaned with deionized water to remove impurities adsorbed on the surface. After cleaning, wipe the substrate dry; or if the substrate is concrete, the substrate is treated by washing it with water to remove impurities adsorbed on the substrate surface, wiping it dry, and applying a sealing undercoat to the substrate surface.

10. The application of the chloride ion penetration inhibiting composite anti-corrosion coating according to any one of claims 1-3 in anti-corrosion engineering, wherein the anti-corrosion engineering is anti-corrosion treatment of steel or concrete in high-salinity water; wherein the high-salinity water is seawater.

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