A method for preparing a conductive metal anticorrosive coating

Abstract

The present application relates to the technical field of corrosion-resistant coating, and particularly relates to a preparation method of conductive metal anticorrosion coating, and the coating prepared by the present application can significantly improve the corrosion resistance of the surface of 304 type stainless steel. Compared with the 304SS bare steel without coating, the corrosion potential of the 304SS under the protection of the coating is obviously increased, and the corrosion current density is obviously decreased. The ZIFs / GO composite material is used as the filler of the epoxy resin coating, and helps to prepare the anticorrosion coating with PPY. The ZIFs has unique crystal structure and chemical properties, the GO has excellent barrier performance and mechanical properties, and the PPY has good conductivity and redox performance. The three are mutually synergistic, so that the coating has better comprehensive performance. The ZIFs / GO composite material can enhance the adhesion between the coating and the substrate, and simultaneously improve the barrier performance of the coating. The PPY surface layer can further improve the conductivity of the coating, which is conducive to the anodic protection performance in the corrosive environment, so as to better protect the substrate metal.

Description

Technical Field

[0001] This invention relates to the field of corrosion-resistant coating technology, and more specifically to a method for preparing a conductive metal anti-corrosion coating. Background Technology

[0002] Metal corrosion is a widespread problem that severely impacts material lifespan and performance. In numerous industrial sectors, such as aerospace, automotive manufacturing, and marine engineering, corrosion of metallic materials leads to structural damage and equipment failure, resulting in significant economic losses and safety hazards. Traditional corrosion testing methods are often time-consuming and struggle to comprehensively and accurately assess the performance of anti-corrosion coatings. Therefore, there is a need for an efficient and accurate accelerated metal corrosion testing method, as well as novel coating materials capable of effectively protecting metals. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the technical solution adopted by this invention is: a method for preparing a conductive metal anti-corrosion coating, comprising the following steps:

[0004] Step A, Raw material preparation: Prepare 1-2 parts graphite powder, 10-20 parts concentrated sulfuric acid, 3-5 parts potassium permanganate, 5-8 parts hydrogen peroxide solution, 30-100 parts deionized water, 1-3 parts inorganic salt, 6-30 parts imidazole ligand, 3-5 parts carbon nanotube dispersion, 1-2 parts epoxy propylene resin and 1 part 304 stainless steel;

[0005] Step B, Preparation of additives: Add graphite powder to concentrated sulfuric acid and stir to obtain a mixture. Then add potassium permanganate to the mixture and stir continuously during the addition process to obtain a reaction mixture. Pour the reaction mixture into ice water and add hydrogen peroxide solution to terminate the reaction to obtain a termination solution. Filter the termination solution to produce a filter cake. Wash the obtained filter cake with deionized water and disperse the washed filter cake in deionized water to obtain a GO suspension.

[0006] Step C, Preparation of composite material: Inorganic salt and imidazole ligand are dissolved in methanol to obtain solution A and solution B respectively; then the GO suspension from step B is added dropwise to solution A and stirred to obtain a mixed solution; then solution B is added dropwise to the mixed solution, stirred and allowed to stand to obtain a composite solution; the composite solution obtained by standing is centrifuged to obtain a pre-composite material; then the pre-composite material is washed with water and methanol; the washed product is placed in a vacuum oven and dried to obtain the composite material.

[0007] Step D, Coating Preparation: First, the carbon nanotube dispersion and epoxy propylene resin are ultrasonically mixed to obtain a mixture. The mixture is then placed in a stirrer and stirred to obtain DCE coating. The composite material obtained in step C is added to the DCE coating and ultrasonically mixed to obtain a coating slurry. The coating slurry is then coated on the surface of 304 stainless steel and dried to obtain the bottom layer coating. Finally, a PPY top layer is prepared on the surface of the bottom layer coating by electrodeposition to obtain the ZIFs / GO / PPY anti-corrosion coating.

[0008] Step E, Performance Testing: The morphology of the material is analyzed using scanning electron microscopy and transmission electron microscopy. The microstructure of the ZIFs / GO / PPY anti-corrosion coating surface is observed to determine the surface roughness. Then, the conductivity and corrosion resistance are tested to obtain a coating with anti-corrosion properties.

[0009] The present invention is further configured such that the preparation of the GO suspension in step B is as follows: Step b1: Under ice-water bath conditions, 10g of graphite powder is added to 200ml of concentrated sulfuric acid while stirring to disperse the graphite powder in the concentrated sulfuric acid, thereby obtaining a mixture; Step b2: 30g of potassium permanganate is gradually added to the mixture in step a1 and stirred to obtain a reaction mixture; Step b3: The reaction mixture in step b2 is transferred to a water bath and reacted at a temperature of 35-40℃ for 1-2 hours, with the stirring speed reduced to 100-200 rpm, to obtain a reaction solution; Step b4: The reaction solution in step b3 is poured into 1000mL of ice water, and then 50mL of 30% hydrogen peroxide solution is added to terminate the reaction; Step b5: The solution in step b4 is filtered using a vacuum filtration device, and the resulting filter cake is washed three times with deionized water; Step b6: The washed filter cake in step b5 is dispersed in deionized water and ultrasonically mixed for 30 minutes to form a GO suspension. The optimized Hummers method for preparing GO suspensions, including ice-water bath conditions, raw material addition sequence, and specific reaction temperature and time, can ensure the quality stability of the GO suspension and improve the reliability of subsequent composite material and coating preparation.

[0010] The present invention is further configured such that, in step C, the inorganic salts are zinc nitrate hexahydrate and cobalt nitrate hexahydrate, the imidazole ligands are dimethylimidazole and dimethylformamide, and the composite material is any one of ZIF-67 / GO, ZIF-8 / GO, and ZIF-7 / GO. The preparation steps of ZIF-67 / GO are as follows: Solution preparation: Cobalt nitrate hexahydrate and dimethylimidazole are dissolved in methanol to obtain solution A and solution B; Solution mixing: The GO suspension from step A is added dropwise to solution A and stirred to obtain a mixed solution, and then solution B is added dropwise... The mixture is added to the solution and stirred. After stirring, it is allowed to stand to obtain a composite solution. Post-treatment: The composite solution obtained after standing is centrifuged to obtain a pre-composite material. The pre-composite material is then washed with water and methanol. The washed product is placed in a vacuum oven and dried to obtain the ZIF-67 / GO composite material. A variety of composite materials (ZIF-67 / GO, ZIF-8 / GO and ZIF-7 / GO) are provided, which enriches the diversity of materials and can be selected according to different needs. The clear preparation steps and parameters ensure the stability of the composite material performance.

[0011] The preparation steps of ZIF-8 / GO are as follows: Solution preparation: Zinc nitrate hexahydrate and dimethylimidazole are dissolved in methanol to obtain solution A and solution B respectively; Solution mixing: The GO suspension in step A is added dropwise to solution A and stirred to obtain a mixed solution. Then, solution B is added dropwise to the mixed solution and stirred. After stirring, the mixture is allowed to stand to obtain a composite solution; Post-treatment: The composite solution obtained after standing is centrifuged to obtain a pre-composite material. The pre-composite material is then washed with water and methanol. The washed product is placed in a vacuum oven and dried to obtain the ZIF-8 / GO composite material.

[0012] The preparation steps of ZIF-7 / GO are as follows: Solution preparation: Zinc nitrate hexahydrate and dimethylformamide are dissolved in methanol to obtain solution A and solution B respectively; Solution mixing: The GO suspension in step A is added dropwise to solution A and stirred to obtain a mixed solution. Then, solution B is added dropwise to the mixed solution and stirred. After stirring, the mixture is allowed to stand to obtain a composite solution; Post-treatment: The composite solution obtained after standing is centrifuged to obtain a pre-composite material. The pre-composite material is then washed with water and methanol. The washed product is placed in a vacuum oven and dried to obtain the ZIF-7 / GO composite material.

[0013] The present invention is further configured such that the anti-corrosion coating in step D is prepared as follows: Step d1: 1.5g of carbon nanotube dispersion and 0.5g of epoxy propylene resin are placed in an ultrasonic cleaner and ultrasonically mixed to obtain a mixture, which is then placed in a stirrer for stirring to obtain DCE coating; Step d2: Any one of ZIF-67 / GO, ZIF-8 / GO and ZIF-7 / GO obtained in step C is added to the DCE coating and ultrasonically mixed in an ultrasonic cleaner to obtain a coating slurry; Step d3: The coating slurry is coated onto the surface of 304 stainless steel by roller coating, and then the coating is applied to the surface of the 304 stainless steel. The stainless steel sheet after coating is placed in an oven and dried to obtain the bottom coating; Step d4: An aqueous solution containing 0.03 mol of pyrrole monomer and 0.05 mol of camphor sulfonic acid is used as the electrolyte; Step d5: A PPY top layer is prepared on the surface of the bottom coating using a constant voltage electrodeposition method, using a three-electrode system, in which 304SS covering the bottom coating is used as the working electrode, a platinum sheet is used as the counter electrode, and a silver-silver chloride electrode is used as the reference electrode; Step d6: The PPY top layer is electrodeposited at a constant voltage potential of +1.4V. By controlling the electrodeposition time, the ZIFs / GO / PPY anti-corrosion coating is finally obtained. The method of preparing the PPY top layer by electrodeposition combines multiple technical means to improve the anti-corrosion performance of the coating. The specific preparation steps include ultrasonic mixing, stirring, roller coating, and constant voltage electrodeposition, making the coating preparation process more controllable and precise.

[0014] The present invention is further configured such that step E includes the following steps: Step e1: Electrochemical impedance spectroscopy and potentiodynamic polarization tests are performed on the nanoparticle composition using Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction instruments, and the morphology of the material is analyzed using scanning electron microscopy and transmission electron microscopy; Step e2: The microstructure of the prepared ZIFs / GO / PPY anti-corrosion coating surface is observed using scanning electron microscopy, and the surface roughness of the ZIFs / GO / PPY anti-corrosion coating is determined using atomic force microscopy; Step e3: The conductivity and corrosion resistance of various coating samples are characterized by electrochemical tests using a 0.1 mol / L HCl solution to simulate an acidic corrosion environment.

[0015] The present invention is further configured such that, in step C, the molar ratio of inorganic salt to imidazole ligand in the preparation of ZIF-67 / GO is 1:6.5, the molar ratio of inorganic salt to imidazole ligand in the preparation of ZIF-8 / GO is 1:10, and the molar ratio of inorganic salt to imidazole ligand in the preparation of ZIF-7 / GO is 1:7.

[0016] The present invention is further configured such that, in step C, the stirring time of the mixed solution is 20 min, the stirring time of the composite solution is 30 min, the standing reaction time is 24 h, in step B, the washing with water and methanol is performed three times, the vacuum drying temperature is 60°C, and the drying time is 24 h.

[0017] The present invention is further configured such that the ultrasonic mixing time of the mixture prepared in step D is 1 hour, the stirring time of the stirrer is 24 hours, the drying temperature of the coated stainless steel sheet is 60°C, and the drying time is 24 hours.

[0018] The present invention is further configured such that the electrodeposition time for the surface layer preparation in step d6 is 1200 seconds, and the coating thickness is 30 μm.

[0019] The present invention is further configured such that the test in step E is performed using a three-electrode system, and the frequency range of the electrochemical impedance spectroscopy test is 10 Hz. -2 -10 5 The Hz frequency and the amplitude selection are 5mV; the scanning rate of the potentiodynamic polarization test is 1mV / s.

[0020] The beneficial effects of this invention are as follows:

[0021] 1. Electrochemical tests conducted according to this invention demonstrate that the coating prepared by this invention can significantly improve the corrosion resistance of 304 stainless steel surfaces. Compared with uncoated bare 304SS steel, the corrosion potential of 304SS under coating protection is significantly increased, while the corrosion current density is significantly reduced. This indicates that the coating can effectively inhibit the corrosion process of metals in acidic environments and extend the service life of metal materials.

[0022] 2. This invention utilizes a ZIFs / GO composite material as a filler in the epoxy resin coating and assists PPY in preparing the anti-corrosion coating. ZIFs possess unique crystal structures and chemical properties, GO exhibits excellent barrier and mechanical properties, and PPY demonstrates good electrical conductivity and redox properties. The synergistic effect of these three materials results in a coating with superior overall performance. The ZIFs / GO composite material enhances the adhesion between the coating and the substrate while improving the coating's barrier properties; the PPY topcoat further enhances the coating's conductivity, facilitating anodic protection in corrosive environments and thus better protecting the base metal.

[0023] 3. The preparation method of this invention is reasonable and relatively simple to operate. First, in the preparation process of ZIFs / GO composite materials, high-quality composite materials can be stably prepared by precisely controlling the ratio of raw materials and reaction conditions. In the preparation of ZIF-67 / GO, ZIF-8 / GO, and ZIF-7 / GO, the molar ratio of metal ions to imidazole ligands, as well as reaction temperature and time, are strictly controlled to ensure the consistency of the composite material's performance. These three materials are composed of different inorganic salts and imidazole ligands, providing researchers with diverse choices. The most suitable composite material can be selected according to different research needs and application scenarios. Second, in the coating preparation process, the preparation methods of the bottom coating and the top coating are both operable. The process steps such as ultrasonication, stirring, roller coating, and electrodeposition are easy to control, which is conducive to realizing industrial production.

[0024] 4. This invention, through the application of an anti-corrosion coating, exhibits excellent anti-corrosion performance and good material synergy, and is expected to have broad application prospects in many fields of metal material corrosion protection. In particular, it effectively solves the problem of easy corrosion of 304 stainless steel in acidic environments, and can be applied to the protection of equipment and structures using 304 stainless steel in industries such as chemical, marine, and construction, reducing maintenance costs and improving the reliability and safety of equipment and structures.

[0025] 5. This invention provides a method for preparing conductive metal anti-corrosion coatings, covering the complete process from additive preparation to coating preparation and performance testing. This allows researchers to conduct metal corrosion studies within a unified system, avoiding disconnections between different experimental stages, improving the accuracy and reliability of the tests. A variety of advanced testing instruments and methods are employed to comprehensively test the nanoparticle composition, material morphology, coating surface microstructure, roughness, conductivity, and corrosion resistance. This enables researchers to gain a deeper understanding of the performance characteristics of the anti-corrosion coating, providing a valuable basis for coating optimization and improvement. Attached Figure Description

[0026] Figure 1 This is an experimental flowchart of the present invention;

[0027] Figure 2 This is the SEM image used in the performance testing of this invention;

[0028] Figure 3 This is a TEM image used in the performance testing of this invention;

[0029] Figure 4 This is a potential polarization curve diagram used in the performance testing of this invention;

[0030] Figure 5 This is a comparison table used in the performance testing of this invention; Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and design various embodiments with various modifications suitable for a particular purpose.

[0032] Example 1: Please refer to Figure 1 - Figure 5 This invention provides a technical solution: a method for preparing a conductive metal anti-corrosion coating, comprising the following steps:

[0033] Step A, Raw material preparation: Prepare 1-2 parts graphite powder, 10-20 parts concentrated sulfuric acid, 3-5 parts potassium permanganate, 5-8 parts hydrogen peroxide solution, 30-100 parts deionized water, 1-3 parts inorganic salt, 6-30 parts imidazole ligand, 3-5 parts carbon nanotube dispersion, 1-2 parts epoxy propylene resin and 1 part 304 stainless steel;

[0034] Step B, Preparation of additives: Add graphite powder to concentrated sulfuric acid and stir to obtain a mixture. Then add potassium permanganate to the mixture and stir continuously during the addition process to obtain a reaction mixture. Pour the reaction mixture into ice water and add hydrogen peroxide solution to terminate the reaction to obtain a termination solution. Filter the termination solution to produce a filter cake. Wash the obtained filter cake with deionized water and disperse the washed filter cake in deionized water to obtain a GO suspension.

[0035] Step C, Preparation of composite material: Inorganic salt and imidazole ligand are dissolved in methanol to obtain solution A and solution B respectively; then the GO suspension from step B is added dropwise to solution A and stirred to obtain a mixed solution; then solution B is added dropwise to the mixed solution, stirred and allowed to stand to obtain a composite solution; the composite solution obtained by standing is centrifuged to obtain a pre-composite material; then the pre-composite material is washed with water and methanol; the washed product is placed in a vacuum oven and dried to obtain the composite material.

[0036] Step D, Coating Preparation: First, the carbon nanotube dispersion and epoxy propylene resin are ultrasonically mixed to obtain a mixture. The mixture is then placed in a stirrer and stirred to obtain DCE coating. The composite material obtained in step C is added to the DCE coating and ultrasonically mixed to obtain a coating slurry. The coating slurry is then coated on the surface of 304 stainless steel and dried to obtain the bottom layer coating. Finally, a PPY top layer is prepared on the surface of the bottom layer coating by electrodeposition to obtain the ZIFs / GO / PPY anti-corrosion coating.

[0037] Step E, Performance Testing: The morphology of the material is analyzed using scanning electron microscopy and transmission electron microscopy. The microstructure of the ZIFs / GO / PPY anti-corrosion coating surface is observed to determine the surface roughness. Then, the conductivity and corrosion resistance are tested to obtain a coating with anti-corrosion properties.

[0038] Example 2: Based on Example 1, a method for preparing a conductive metal anti-corrosion coating includes the following steps:

[0039] Step A, Raw material preparation: Prepare 1-2 parts graphite powder, 10-20 parts concentrated sulfuric acid, 3-5 parts potassium permanganate, 5-8 parts hydrogen peroxide solution, 30-100 parts deionized water, 1-3 parts inorganic salt, 6-30 parts imidazole ligand, 3-5 parts carbon nanotube dispersion, 1-2 parts epoxy propylene resin and 1 part 304 stainless steel;

[0040] Step B, Preparation of additives: Add graphite powder to concentrated sulfuric acid and stir to obtain a mixture. Then add potassium permanganate to the mixture and stir continuously during the addition process to obtain a reaction mixture. Pour the reaction mixture into ice water and add hydrogen peroxide solution to terminate the reaction to obtain a termination solution. Filter the termination solution to produce a filter cake. Wash the obtained filter cake with deionized water and disperse the washed filter cake in deionized water to obtain a GO suspension.

[0041] Step C, Preparation of composite material: Inorganic salt and imidazole ligand are dissolved in methanol to obtain solution A and solution B respectively; then the GO suspension from step B is added dropwise to solution A and stirred to obtain a mixed solution; then solution B is added dropwise to the mixed solution, stirred and allowed to stand to obtain a composite solution; the composite solution obtained by standing is centrifuged to obtain a pre-composite material; then the pre-composite material is washed with water and methanol; the washed product is placed in a vacuum oven and dried to obtain the composite material.

[0042] Step D, Coating Preparation: First, the carbon nanotube dispersion and epoxy propylene resin are ultrasonically mixed to obtain a mixture. The mixture is then placed in a stirrer and stirred to obtain DCE coating. The composite material obtained in step C is added to the DCE coating and ultrasonically mixed to obtain coating slurry. The coating slurry is then coated on the surface of 304 stainless steel and dried to obtain ZIF-67 / Go coating.

[0043] Example 3: Based on Example 1, a method for preparing a conductive metal anti-corrosion coating includes the following steps:

[0044] Step A, Raw material preparation: 1-3 parts inorganic salt, 6-30 parts imidazole ligand, 3-5 parts carbon nanotube dispersion, 1-2 parts epoxy propylene resin and 1 part 304 stainless steel;

[0045] Step B, preparation of composite material: Inorganic salt and imidazole ligand are dissolved in methanol to obtain solution A and solution B respectively. Solution B is then added dropwise to solution A. After stirring, the mixture is allowed to stand to obtain a composite solution. The composite solution obtained after standing is centrifuged to obtain a pre-composite material. The pre-composite material is then washed with water and methanol. The washed product is placed in a vacuum oven and dried to obtain the composite material.

[0046] Step C, Coating Preparation: First, the carbon nanotube dispersion and epoxy propylene resin are ultrasonically mixed to obtain a mixture. The mixture is then placed in a stirrer and stirred to obtain DCE coating. The composite material obtained in Step C is added to the DCE coating and ultrasonically mixed to obtain a coating slurry. The coating slurry is then applied to the surface of 304 stainless steel and dried to obtain the bottom coating.

[0047] Step D, Performance Testing: The morphology of the material is analyzed using scanning electron microscopy and transmission electron microscopy. The microstructure of the resin coating containing ZIF-67 is observed to determine the surface roughness. Then, the conductivity and corrosion resistance are tested.

[0048] Performance testing:

[0049] In use, coatings were prepared according to the methods of Examples 1, 2 and 3 respectively as Experiment 1, Experiment 2 and Experiment 3. Bare 304 stainless steel and coatings prepared with pure resin coating were taken as Control 1 and Control 2 for testing.

[0050] Test results can be obtained through Figure 2 The SEM and TEM images of ZIF-67 (a1-a3) and ZIF-67 / GO (b1-b3) were observed. Figure 3The images show SEM and AFM images of pure resin coatings (a1-a2), resin coatings containing ZIF-67 filler (b1-b2), resin coatings containing ZIF-67 / GO filler (c1-c2), and ZIF-67 / GO / PPY. Experimental groups 1, 2, 3, control group 1, and control group 2 were then placed in a simulated corrosion environment of 0.1 mol / L HCl solution for comparison. Figure 4 and through Figure 5 The results of potentiodynamic polarization of bare 304 stainless steel and four coatings in a 0.1 mol / L HCl solution were obtained by fitting E using the Tafel extrapolation method. corr andi corr Specific parameters are as follows Figure 5 As shown in Table 1, the E of 304SS bare steel... corr and i corr The values ​​are -0.41V and 2.36×10, respectively. -5 A·cm 2 And all the E of 304SS under the protection of the coating corr Both showed significant increases, including an underlayer containing ZIF-67 / GO filler and a ZIF-67 / GO / PPY coating containing a PPY top layer. corr The highest value indicates that the presence of this coating significantly reduces the corrosion rate of 304SS, thus significantly improving its corrosion resistance. This applies to the ZIF-67 / GO / PPY coating. corr On the contrary, this special polarization phenomenon is enhanced, which is a special phenomenon caused by the good redox ability of PPY itself. The polarization data of PPY-containing samples were obtained by Tafel extrapolation. corr It is the sum of the current density generated by the redox reaction in the coating and the dissolution of the matrix, and can be considered as the i of the PPY coating sample. corr Most of them are produced by redox reactions. redox The composition of the matrix, and the actual i produced by the dissolution of the matrix. redox At very small sizes, the coating provides excellent corrosion protection.

[0051] Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art and related fields based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described and explained in the present invention, unless otherwise specified or limited, shall be implemented according to conventional means in the art.

Claims

1. A method for preparing a conductive metal anti-corrosion coating, characterized in that, Includes the following steps: Step A, Raw material preparation: Prepare 1-2 parts graphite powder, 10-20 parts concentrated sulfuric acid, 3-5 parts potassium permanganate, 5-8 parts hydrogen peroxide solution, 30-100 parts deionized water, 1-3 parts inorganic salt, 6-30 parts imidazole ligand, 3-5 parts carbon nanotube dispersion, 1-2 parts epoxy propylene resin and 1 part 304 stainless steel; Step B, Preparation of additives: Graphite powder is added to concentrated sulfuric acid and stirred to obtain a mixture. Potassium permanganate is then added to the mixture while stirring continuously to obtain a reaction mixture. The reaction mixture is poured into ice water and hydrogen peroxide solution is added to terminate the reaction to obtain a termination solution. The termination solution is then filtered to produce a filter cake. The obtained filter cake is washed with deionized water and dispersed in deionized water to obtain a GO suspension. Step C, Preparation of composite material: Inorganic salt and imidazole ligand are dissolved in methanol to obtain solution A and solution B respectively; then the GO suspension from step B is added dropwise to solution A and stirred to obtain a mixed solution; then solution B is added dropwise to the mixed solution, stirred and allowed to stand to obtain a composite solution; the composite solution obtained by standing is centrifuged to obtain a pre-composite material; then the pre-composite material is washed with water and methanol; the washed product is placed in a vacuum oven and dried to obtain the composite material. Step D, Coating Preparation: First, the carbon nanotube dispersion and epoxy propylene resin are ultrasonically mixed to obtain a mixture. The mixture is then placed in a stirrer and stirred to obtain DCE coating. The composite material obtained in step C is added to the DCE coating and ultrasonically mixed to obtain a coating slurry. The coating slurry is then coated on the surface of 304 stainless steel and dried to obtain the bottom layer coating. Finally, a PPY top layer is prepared on the surface of the bottom layer coating by electrodeposition to obtain the ZIFs / GO / PPY anti-corrosion coating. Step E, Performance Testing: The morphology of the material is analyzed using scanning electron microscopy and transmission electron microscopy, and the microstructure of the ZIFs / GO / PPY anti-corrosion coating surface is observed to determine the surface roughness. Then, the conductivity and corrosion resistance are tested to obtain a coating with anti-corrosion properties. In step C, the inorganic salt is zinc nitrate hexahydrate or cobalt nitrate hexahydrate, the imidazole ligand is dimethylimidazole, and the composite material is either ZIF-67 / GO or ZIF-8 / GO. The preparation steps of ZIF-67 / GO are as follows: Solution preparation: Cobalt nitrate hexahydrate and dimethylimidazole were dissolved in methanol to obtain solution A and solution B, respectively. Solution mixing: Add the GO suspension from step B to solution A and stir to mix to obtain a mixed solution. Then add solution B to the mixed solution dropwise and stir. After stirring, let it stand to obtain a composite solution. Post-processing: The composite solution obtained by standing was centrifuged to obtain a pre-composite material. The pre-composite material was then washed with water and methanol. The washed product was placed in a vacuum oven and dried to obtain the ZIF-67 / GO composite material. The preparation steps of the ZIF-8 / GO are as follows: Solution preparation: Dissolve zinc nitrate hexahydrate and dimethylimidazole in methanol to obtain solution A and solution B, respectively; Solution mixing: Add the GO suspension from step B to solution A and stir to mix to obtain a mixed solution. Then add solution B to the mixed solution dropwise and stir. After stirring, let it stand to obtain a composite solution. Post-processing: The composite solution obtained by standing was centrifuged to obtain a pre-composite material. The pre-composite material was then washed with water and methanol. The washed product was placed in a vacuum oven and dried to obtain the ZIF-8 / GO composite material.

2. The method for preparing a conductive metal anti-corrosion coating according to claim 1, characterized in that: The GO suspension in step B is prepared as follows: Step b1: Under ice-water bath conditions, add 10g of graphite powder to 200ml of concentrated sulfuric acid while stirring to disperse the graphite powder in the concentrated sulfuric acid and obtain a mixture; Step b2: Gradually add 30g of potassium permanganate to the mixture from step b1 and mix and stir to obtain the reaction mixture: Step b3: Transfer the reaction mixture from step b2 to a water bath and continue the reaction in the water bath at a temperature of 35-40°C for 1-2 hours, while reducing the stirring speed to 100-200 rpm to obtain the reaction solution; Step b4: Pour the reaction solution from step b3 into 1000 mL of ice water, and then add 50 mL of 30% hydrogen peroxide solution to terminate the reaction; Step b5: Filter the solution from step b4 using a vacuum filtration device, and wash the resulting filter cake three times with deionized water. Step b6: Disperse the washed filter cake from step b5 in deionized water and mix it by ultrasonication for 30 minutes to form a GO suspension.

3. The method for preparing a conductive metal anti-corrosion coating according to claim 1, characterized in that: The anti-corrosion coating in step D is prepared as follows: Step d1: Place 1.5g of carbon nanotube dispersion and 0.5g of epoxy propylene resin in an ultrasonic cleaner and mix them ultrasonically to obtain a mixture. Then, place the mixture in a stirrer and stir to obtain DCE coating. Step d2: Add either ZIF-67 / GO or ZIF-8 / GO obtained in step C to the DCE coating, and place it in an ultrasonic cleaner for ultrasonic mixing to obtain a coating slurry. Step d3: Apply the coating slurry to the surface of 304 stainless steel using a roller coating method, and then place the coated stainless steel sheet into an oven to dry and obtain the bottom coating. Step d4: Take an aqueous solution containing 0.03 mol of pyrrole monomer and 0.05 mol of camphor sulfonic acid as the electrolyte; Step d5: A PPY top layer is prepared on the surface of the bottom coating using a constant voltage electrodeposition method. A three-electrode system is used, in which 304SS covering the bottom coating is used as the working electrode, a platinum sheet is used as the counter electrode, and a silver-silver chloride electrode is used as the reference electrode. Step d6: Electrodeposit the PPY surface layer at a constant voltage potential of +1.4V. By controlling the electrodeposition time, the ZIFs / GO / PPY anti-corrosion coating is finally obtained.

4. The method for preparing a conductive metal anti-corrosion coating according to claim 1, characterized in that: Step E includes the following steps: Step e1: The composition of the nanoparticles was tested by electrochemical impedance spectroscopy and potentiodynamic polarization using Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction instruments, and the morphology of the material was analyzed by scanning electron microscopy and transmission electron microscopy. Step e2: The surface microstructure of the prepared ZIFs / GO / PPY anti-corrosion coating was observed using a scanning electron microscope, and the surface roughness of the ZIFs / GO / PPY anti-corrosion coating was determined using an atomic force microscope. Step e3: Simulate an acidic corrosion environment with 0.1 mol / L HCl solution, and characterize the conductivity and corrosion resistance of various coating samples through electrochemical tests.

5. The method for preparing a conductive metal anti-corrosion coating according to claim 1, characterized in that: In step C, the molar ratio of inorganic salt to imidazole ligand in the ZIF-67 / GO preparation is 1:6.5, and the molar ratio of inorganic salt to imidazole ligand in the ZIF-8 / GO preparation is 1:

10.

6. The method for preparing a conductive metal anti-corrosion coating according to claim 1, characterized in that: In step C, the stirring time of the mixed solution is 20 min, the stirring time of the composite solution is 30 min, the standing reaction time is 24 h, the washing with water and methanol is performed three times in step B, and the temperature of the vacuum oven is 60°C.

7. The method for preparing a conductive metal anti-corrosion coating according to claim 3, characterized in that: In step D, the ultrasonic mixing time of the bottom layer preparation solution is 1 hour, the stirring time of the stirrer is 24 hours, and the drying temperature of the coated stainless steel sheet is 60°C.

8. The method for preparing a conductive metal anti-corrosion coating according to claim 3, characterized in that: In step d6, the electrodeposition time for the surface layer preparation is 1200 seconds, and the coating thickness is 30 μm.

9. The method for preparing a conductive metal anti-corrosion coating according to claim 4, characterized in that: The test in step E is performed using a three-electrode system, and the frequency range of the electrochemical impedance spectroscopy test is [missing information]. The Hz frequency and the amplitude selection are 5mV; the scanning rate of the potentiodynamic polarization test is 1 mV / s.

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