A surface corrosion-proofing process for stainless steel pipes

Abstract

This invention relates to the field of metal pipe processing technology, specifically disclosing a surface anti-corrosion treatment process for stainless steel pipes. The process includes the following steps: S1, pretreatment: mechanically polishing the stainless steel pipe and then degreasing it; S2, pickling: immersing the pretreated stainless steel pipe in an acid solution for pickling; S3, passivation: immersing the pickled stainless steel pipe in a passivation solution for passivation treatment; S4, coating the outer surface of the passivated stainless steel pipe with a composite anti-corrosion reinforcing coating, curing it, and completing the anti-corrosion treatment. This invention prepares a composite anti-corrosion reinforcing coating by compounding self-made slow-release rust-inhibiting reinforcing particles, anti-corrosion modified lamellar fillers, water-based polyurethane resin, water-soluble silicone-acrylic resin, and other additives. By applying this composite anti-corrosion reinforcing coating to the surface of stainless steel pipes, the anti-corrosion performance of the stainless steel pipes can be significantly improved, and long-term rust prevention and antibacterial properties can be imparted.

Description

Technical Field

[0001] This invention relates to the field of metal pipe processing technology, and in particular to a surface anti-corrosion treatment process for stainless steel pipes. Background Technology

[0002] Stainless steel pipes possess excellent mechanical strength and are widely used in industry. However, when applied in high-humidity outdoor environments, such as marine environments, they are prone to corrosion, leading to a decline in mechanical properties and affecting their service life. Furthermore, in such high-humidity environments, stainless steel pipes are susceptible to bacterial growth, and the metabolic products of bacteria (such as H2S and organic acids) exacerbate corrosion.

[0003] Coating the surface of stainless steel pipes with anti-corrosion coatings is a common method to improve their anti-corrosion performance. For example, patent CN121945388A provides a high-performance anti-corrosion stainless steel pipe fitting and its preparation method, and CN119634203B provides an application of a corrosion-resistant stainless steel pipe and its preparation method in marine engineering. However, patent CN119634203B uses a modified polyurethane coating with epoxy-modified carbon quantum dots grafted onto titanium dioxide as a method coating, which can effectively improve anti-corrosion performance and impart certain antibacterial properties. It also describes that the introduced carbon quantum dots have good antibacterial and optical properties, providing a feasible strategy for antibacterial functionalization of the coating. However, this patent does not discuss or study the preparation process and mechanism of action of the carbon quantum dots, and the tendency of carbon dots to aggregate affects their performance. This problem is not properly solved in this patent. Furthermore, it does not reliably improve the adhesion performance between the coating and the substrate. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a surface anti-corrosion treatment process for stainless steel pipes, which addresses the shortcomings of the prior art.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a stainless steel pipe surface anti-corrosion treatment process, comprising the following steps: S1. Pretreatment: The stainless steel pipe is mechanically polished and then degreased. S2. Pickling: The pretreated stainless steel pipe is placed in acid solution for pickling. S3. Passivation: The pickled stainless steel pipe is placed in a passivation solution for passivation treatment. S4. Apply a composite anti-corrosion and reinforcing coating to the outer surface of the passivated stainless steel pipe, cure it, and complete the anti-corrosion treatment. The composite anti-corrosion and reinforcing coating comprises the following components in parts by weight: The ingredients are: 30-55 parts waterborne polyurethane resin, 45-70 parts water-soluble silicone-acrylic resin, 8-16 parts slow-release rust-inhibiting reinforcing particles, 10-32 parts anti-corrosion modified lamellar filler, 10-25 parts curing agent, 1.5-4 parts dispersant, 0.9-3.5 parts adhesion promoter, 1-4 parts film-forming aid, 0.5-1 parts defoamer, and 30-50 parts deionized water. The slow-release rust-preventive reinforcing particles are prepared by the following method: 1-1) Zinc ammonium phosphate was loaded onto mesoporous alumina to obtain zinc ammonium phosphate-mesoporous alumina composite particles; 1-2) Surface modification of zinc ammonium phosphate-mesoporous alumina composite particles was carried out using silane coupling agents to obtain slow-release rust-preventing and reinforcing particles; The corrosion-resistant modified sheet filler is prepared by the following method: 2-1) Pretreatment of basalt flakes; 2-2) Carbon dots were synthesized in situ on pretreated basalt flakes to obtain basalt flake-carbon dot composites; 2-3) The surface of the basalt flake-carbon dot composite was modified by using a silane coupling agent to obtain the modified basalt flake-carbon dot composite. 2-4) Grafting polyaniline-polyacrylate copolymer onto modified basalt flake-carbon dot composite yields corrosion-resistant modified sheet filler.

[0006] Preferably, the degreasing solution comprises the following components: water, sodium hydroxide, sodium phosphate, sodium gluconate, and fatty alcohol polyoxyethylene ether; the passivation solution comprises the following components: water, sodium silicate, hydrogen peroxide, citric acid, and phosphoric acid.

[0007] Preferably, the surface anti-corrosion treatment process for the stainless steel pipe includes the following steps: S1. Pretreatment: After mechanical polishing, the stainless steel pipe is placed in a degreasing solution and soaked for 10-40 minutes before being taken out and rinsed with water. The degreasing solution comprises the following components by weight: 250-1000 parts water, 6-24 parts sodium hydroxide, 12-40 parts sodium phosphate, 2-10 parts sodium gluconate, and 0.5-1.5 parts fatty alcohol polyoxyethylene ether. S2. Pickling: Place the pretreated stainless steel pipe in acid solution, soak for 2-10 minutes, then take it out and wash with water. The solvent in the acid solution is deionized water, and the acid solution includes the following components: sulfuric acid 30-90 g / L, phosphoric acid 10-40 g / L; S3. Passivation: Immerse the pickled stainless steel pipe in the passivation solution at 35-60℃ for 15-60 minutes, then take it out, wash it with water, and dry it. The passivation solution includes the following components: 250-1000L of water, 9-36kg of sodium silicate, 5-20L of hydrogen peroxide with a concentration of 10-20wt%, 3-12kg of citric acid, and 1-4L of phosphoric acid with a concentration of 60-85wt%. S4. Apply a composite anti-corrosion and reinforcing coating to the outer surface of the passivated stainless steel pipe, with a coating amount of 150-300 g / m. 2 After coating, cure at 70-90℃ for 1-4 hours to complete the anti-corrosion treatment.

[0008] Preferably, the silane coupling agent used in steps 1-2) and 2-3) is KH570.

[0009] Preferably, the slow-release rust-inhibiting and reinforcing particles are prepared by the following method: 1-1) Mesoporous alumina and surfactant were added to deionized water, ultrasonically dispersed, and then zinc sulfate was added. After stirring and standing, diammonium hydrogen phosphate was added, the pH was adjusted to 8-10, and the reaction was carried out under heating and stirring. After aging, centrifugation, solid washing and drying were performed to obtain zinc ammonium phosphate-mesoporous alumina composite particles. 1-2) Take zinc ammonium phosphate-mesoporous alumina composite particles and deionized water, add them to ethanol, stir, add silane coupling agent KH570 dropwise, stir and react under heating, filter, wash and dry the solid to obtain slow-release rust-preventing and reinforcing particles.

[0010] Preferably, the surfactant used in step 1-1) is one or more of PEG 400, PEG 600, PEG 1000, PEG2000 and PEG 4000.

[0011] Preferably, the slow-release rust-inhibiting and reinforcing particles are prepared by the following method: 1-1) Zinc ammonium phosphate was loaded onto mesoporous alumina to prepare zinc ammonium phosphate-mesoporous alumina composite particles: Add 5-20g of mesoporous alumina and 0.25-1g of PEG 600 to 250-1000mL of deionized water and sonicate for 0.5-2h. Then add 1.6-6.4g of zinc sulfate, stir for 15-60min, and let stand for 0.5-2h. Then add 1.3-5.5g of diammonium hydrogen phosphate, adjust the pH to 8-10 with ammonia, stir and react at 40-55℃ for 6-24h, age at room temperature for 8-30h, centrifuge, wash the solid with ethanol until neutral, and dry to obtain zinc ammonium phosphate-mesoporous alumina composite particles. 1-2) Surface modification of zinc ammonium phosphate-mesoporous alumina composite particles using silane coupling agent KH570: Take 2.5-10g of zinc ammonium phosphate-mesoporous alumina composite particles and 10-40mL of deionized water and add them to 80-350mL of ethanol. Stir for 45-180min, then add 0.9-3.6g of silane coupling agent KH570 dropwise. Stir and reflux at 70-90℃ for 6-24h, filter, wash the solid with ethanol, and vacuum dry to obtain slow-release rust-inhibiting and reinforcing particles.

[0012] Preferably, the corrosion-resistant modified lamellar filler is prepared by the following method: 2-1) Basalt flake pretreatment: Add basalt flakes to hydrochloric acid, heat and stir under reflux, filter, wash and dry; 2-2) Pretreated basalt flakes and ethanol were added to deionized water, ultrasonically dispersed, and then sodium hexametaphosphate, citric acid, α-phenylethylamine and urea were added. The mixture was stirred and transferred to a reaction vessel. The mixture was heated and reacted, cooled, filtered, and the solid was washed and dried to obtain basalt flake-carbon dot composite. 2-3) Take basalt flake-carbon dot composite and deionized water and add them to ethanol. After stirring for 1 minute, add silane coupling agent KH570 dropwise, heat and stir to react, filter, wash and dry the solid to obtain modified basalt flake-carbon dot composite. 2-4) Grafting polyaniline-polyacrylate copolymer onto modified basalt flake-carbon dot composite: 2-4-1) Add modified basalt flake-carbon point complex and sodium dodecylbenzenesulfonate to deionized water, disperse by ultrasonication, add acrylic acid, hydroxyethyl acrylate and methyl methacrylate, stir with nitrogen gas, add initiator aqueous solution dropwise, and stir under heating to react; 2-4-2) Cool, add aniline, stir, add initiator aqueous solution dropwise, stir and react at room temperature, filter, wash and dry the solid to obtain corrosion-resistant modified sheet packing.

[0013] Preferably, the corrosion-resistant modified lamellar filler is prepared by the following method: 2-1) Basalt flake pretreatment: Add 2.5-10g of basalt flakes to 200-800mL of hydrochloric acid with a concentration of 2-8mol / L, stir and reflux at 60-80℃ for 10-36h, filter, wash with deionized water, and dry. 2-2) In-situ synthesis of carbon dots on pretreated basalt flakes: 1.5-6 g of pretreated basalt flakes and 15-60 mL of ethanol were added to 50-200 mL of deionized water and ultrasonically dispersed for 20-60 min. Then, 0.3-1.22 g of sodium hexametaphosphate, 0.6-2.4 g of citric acid, 0.18-0.72 g of α-phenylethylamine, and 0.12-0.48 g of urea were added and stirred for 10-40 min. The resulting mixture was transferred to a reaction vessel and reacted at 160-200 °C for 12-48 h. After cooling, the mixture was filtered, the solid was washed with deionized water, and dried under vacuum to obtain the basalt flake-carbon dot composite. 2-3) Surface modification of basalt flake-carbon dot composites using silane coupling agent KH570: Take 1.5-6g of basalt flake-carbon dot composite and 7-30mL of deionized water and add them to 50-200mL of ethanol. Stir for 0.5-2h, then add 0.7-2.8g of silane coupling agent KH570 dropwise. Stir and react at 65-90℃ for 6-24h. Filter, wash the solid with ethanol, and dry under vacuum to obtain the modified basalt flake-carbon dot composite. 2-4) Grafting polyaniline-polyacrylate copolymer onto modified basalt flake-carbon dot composite: 2-4-1) Take 1.5-6g of modified basalt flake-carbon point composite and 0.7-2.8g of sodium dodecylbenzenesulfonate and add them to 60-240mL of deionized water. Disperse by ultrasonication for 30-90min. Then add 1-4g of acrylic acid, 0.75-3g of hydroxyethyl acrylate and 2-8g of methyl methacrylate. Stir under nitrogen for 15-60min and then add 10-30mL of initiator aqueous solution containing 0.05-0.15g of ammonium persulfate. Stir and react at 60-85℃ for 1-4h. 2-4-2) Cool to room temperature, add 3.5-15g aniline, stir for 5-20min, add 10-30mL of initiator aqueous solution containing 0.05-0.15g ammonium persulfate, stir and react at room temperature for 12-36h, filter, wash the solid with deionized water, and vacuum dry to obtain corrosion-resistant modified sheet packing.

[0014] Preferably, the composite anti-corrosion reinforced coating comprises the following components in parts by weight: The mixture contains 42 parts of waterborne polyurethane resin, 58 parts of water-soluble silicone-acrylic resin, 14 parts of slow-release rust-inhibiting reinforcing particles, 16 parts of anti-corrosion modified lamellar filler, 17 parts of curing agent, 2.5 parts of dispersant, 1.8 parts of adhesion promoter, 2 parts of film-forming aid, 0.5 parts of defoamer, and 40 parts of deionized water.

[0015] The beneficial effects of this invention are: In the stainless steel pipe surface anti-corrosion treatment process provided by this invention, a composite anti-corrosion reinforced coating is prepared by compounding self-made slow-release rust-inhibiting reinforcing particles, anti-corrosion modified lamellar fillers, water-based polyurethane resin, water-soluble silicone acrylic resin, and other additives. By applying this composite anti-corrosion reinforced coating to the surface of the stainless steel pipe, the anti-corrosion performance of the stainless steel pipe can be significantly improved, and it can also give it long-term rust prevention and antibacterial properties, thereby improving the application effect of stainless steel pipe in corrosive environments (such as marine environments) and extending its service life.

[0016] In the slow-release rust-preventing reinforcing particles of this invention, zinc ammonium phosphate is loaded onto mesoporous alumina, which has a large specific surface area and high stability. This improves the dispersion effect of zinc ammonium phosphate. The zinc ammonium phosphate loaded on the surface of the mesoporous alumina can provide rust prevention in the early stage, while the zinc ammonium phosphate loaded inside the pore structure of the mesoporous alumina can be slowly released to the outside, providing a long-lasting slow-release effect. This prolongs the rust prevention time of zinc ammonium phosphate, avoids excessive consumption of zinc ammonium phosphate, and improves its rust prevention efficiency. Furthermore, the mesoporous alumina itself can also improve the wear resistance, corrosion resistance, and weather resistance of the coating formed by the paint, and is beneficial to improving the adhesion between the coating and the stainless steel pipe substrate.

[0017] In the corrosion-modified lamellar filler of this invention, the carbon dots deposited on the basalt flakes can, on the one hand, increase the surface roughness, which is beneficial to improving the interfacial bonding strength between the basalt flakes and the resin system; on the other hand, they have the ability to efficiently generate active oxygen under light irradiation. The generated active oxygen has excellent sterilization effect, thereby endowing the coating with good antibacterial properties. Furthermore, the loading of the lamellar basalt flakes significantly improves the dispersion and stability of the carbon dots, thus enhancing the efficiency of active oxygen generation. Therefore, the stainless steel pipe prepared by the process of this invention is particularly suitable for outdoor environments exposed to sunlight, such as marine environments. When used in marine environments, the excellent antibacterial properties can effectively reduce the attachment of plankton and improve the ability to resist biofouling.

[0018] In the composite anti-corrosion and reinforcing coating of the present invention, the release-type rust-inhibiting and reinforcing particles can continuously release the rust-inhibiting functional component zinc ammonium phosphate, and the anti-corrosion modified lamellar filler provides excellent physical barrier and corrosion resistance enhancement effect. The two work together to significantly improve the anti-corrosion performance of the coating. Attached Figure Description

[0019] Figure 1 The infrared absorption spectrum of the zinc ammonium phosphate-mesoporous alumina composite particles prepared in Example 1; Figure 2 Infrared absorption spectrum of the basalt flake-carbon dot composite prepared in Example 2-1; Figure 3 The results are from the antibacterial principle test. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to embodiments, so that those skilled in the art can implement it based on the description.

[0021] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0022] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials and reagents used in the following examples are commercially available. For examples where specific conditions are not specified, conventional conditions or conditions recommended by the manufacturer are followed. For reagents or instruments whose manufacturers are not specified, they are all commercially available products.

[0023] This invention provides a surface anti-corrosion treatment process for stainless steel pipes, comprising the following steps: S1. Pretreatment: The stainless steel pipe is mechanically polished and then degreased. S2. Pickling: The pretreated stainless steel pipe is placed in acid solution for pickling. S3. Passivation: The pickled stainless steel pipe is placed in a passivation solution for passivation treatment. S4. Apply a composite anti-corrosion and reinforcing coating to the outer surface of the passivated stainless steel pipe, cure it, and complete the anti-corrosion treatment. Composite anti-corrosion reinforced coatings comprise the following components by weight: The ingredients are: 30-55 parts waterborne polyurethane resin, 45-70 parts water-soluble silicone-acrylic resin, 8-16 parts slow-release rust-inhibiting reinforcing particles, 10-32 parts anti-corrosion modified lamellar filler, 10-25 parts curing agent, 1.5-4 parts dispersant, 0.9-3.5 parts adhesion promoter, 1-4 parts film-forming aid, 0.5-1 parts defoamer, and 30-50 parts deionized water.

[0024] The slow-release rust-preventive reinforcing particles were prepared by the following method: 1-1) Mesoporous alumina and surfactant were added to deionized water, ultrasonically dispersed, and then zinc sulfate was added. After stirring and standing, diammonium hydrogen phosphate was added, the pH was adjusted to 8-10, and the reaction was carried out under heating and stirring. After aging, centrifugation, solid washing and drying were performed to obtain zinc ammonium phosphate-mesoporous alumina composite particles. 1-2) Take zinc ammonium phosphate-mesoporous alumina composite particles and deionized water, add them to ethanol, stir, add silane coupling agent KH570 dropwise, stir and react under heating, filter, wash and dry the solid to obtain slow-release rust-preventing and reinforcing particles.

[0025] The corrosion-resistant modified sheet filler was prepared by the following method: 2-1) Basalt flake pretreatment: Add basalt flakes to hydrochloric acid, heat and stir under reflux, filter, wash and dry; 2-2) Pretreated basalt flakes and ethanol were added to deionized water, ultrasonically dispersed, and then sodium hexametaphosphate, citric acid, α-phenylethylamine and urea were added. The mixture was stirred and transferred to a reaction vessel. The mixture was heated and reacted, cooled, filtered, and the solid was washed and dried to obtain basalt flake-carbon dot composite. 2-3) Take basalt flake-carbon dot composite and deionized water and add them to ethanol. After stirring for 1 minute, add silane coupling agent KH570 dropwise, heat and stir to react, filter, wash and dry the solid to obtain modified basalt flake-carbon dot composite. 2-4) Grafting polyaniline-polyacrylate copolymer onto modified basalt flake-carbon dot composite: 2-4-1) Add modified basalt flake-carbon point complex and sodium dodecylbenzenesulfonate to deionized water, disperse by ultrasonication, add acrylic acid, hydroxyethyl acrylate and methyl methacrylate, stir with nitrogen gas, add initiator aqueous solution dropwise, and stir under heating to react; 2-4-2) Cool, add aniline, stir, add initiator aqueous solution dropwise, stir and react at room temperature, filter, wash and dry the solid to obtain corrosion-resistant modified sheet packing.

[0026] Invention Mechanism This invention prepares a composite anti-corrosion and reinforcing coating by compounding self-made slow-release rust-inhibiting reinforcing particles, anti-corrosion modified lamellar fillers, water-based polyurethane resin, water-soluble silicone acrylic resin, and other additives. By applying this composite anti-corrosion and reinforcing coating to the surface of stainless steel pipes, the anti-corrosion performance of stainless steel pipes can be significantly improved, and long-term rust prevention and antibacterial properties can be given to them. This can improve the application effect of stainless steel pipes in corrosive environments (such as marine environments) and extend their service life.

[0027] 1. Slow-release rust-preventive reinforcing particles The slow-release rust-preventing and reinforcing particles are composite particles obtained by in-situ synthesis of zinc ammonium phosphate on mesoporous alumina, loading zinc ammonium phosphate onto the surface and mesoporous structure of the mesoporous alumina, and then surface modification with a silane coupling agent.

[0028] Zinc ammonium phosphate is a rust inhibitor. Compared with conventional zinc phosphate rust inhibitors, it has advantages such as strong hydrolysis ability and faster rust prevention start-up speed. Furthermore, the NH4⁺ released by zinc ammonium phosphate in the aqueous environment can regulate the local pH and inhibit cathodic reactions. Loading zinc ammonium phosphate onto mesoporous alumina, which has a large specific surface area and high stability, improves the dispersion effect of zinc ammonium phosphate. Zinc ammonium phosphate loaded on the surface of mesoporous alumina provides early rust prevention, while zinc ammonium phosphate loaded inside the pore structure of mesoporous alumina can be slowly released to the outside, providing a long-lasting slow-release effect. This extends the rust prevention time of zinc ammonium phosphate, prevents excessive consumption of zinc phosphate, and improves its rust prevention efficiency. Mesoporous alumina itself also improves the wear resistance, corrosion resistance, and weather resistance of the coating formed, and helps to improve the adhesion of the coating to the stainless steel pipe substrate.

[0029] Surface modification of zinc ammonium phosphate-mesoporous alumina composite particles by using silane coupling agent KH570 can improve the compatibility between the composite particles and the resin system in the coating, improve its dispersion performance, and reduce its agglomeration.

[0030] 2. Corrosion-resistant modified sheet packing The corrosion-resistant modified lamellar filler in this invention is obtained by depositing carbon dots on basalt flakes, followed by silane coupling agent modification and grafting onto polyaniline-polyacrylate copolymer. First, the basalt flakes are soaked in hydrochloric acid to remove surface impurities, increase surface roughness, and generate a certain amount of metal ions on the surface, which facilitates the in-situ deposition of carbon dots. Silane coupling agent modification introduces double bonds, which can participate in the polymerization reaction during the subsequent grafting polymer process, thereby facilitating the strong grafting of polyaniline-polyacrylate copolymer.

[0031] Basalt flakes possess excellent acid and alkali resistance and corrosion resistance, and can form a layered tortuous structure in polymers, which can improve the resistance to media penetration, thereby significantly enhancing the anti-corrosion performance of the coating. At the same time, it can also improve the wear resistance of the coating (Wu Zonghan, Duan Zhixin. Performance and application of flake anti-corrosion coatings [J]. Modern Coatings and Painting, 2010, 013(007):21-24.DOI:10.3969 / j.issn.1007-9548.2010.07.007.).

[0032] In this invention, the carbon dots deposited on basalt flakes can, on the one hand, increase surface roughness, which is beneficial to improving the interfacial bonding strength between the basalt flakes and the resin system; on the other hand, they possess the ability to efficiently generate active oxygen under light irradiation. The generated active oxygen has excellent sterilization effects, thus endowing the coating with good antibacterial properties. Furthermore, the loading of the basalt flakes with their lamellar structure significantly improves the dispersibility and stability of the carbon dots, thereby enhancing the efficiency of active oxygen generation. Therefore, the stainless steel pipe prepared by this invention is particularly suitable for outdoor environments exposed to sunlight, such as marine environments. When used in marine environments, its excellent antibacterial properties can effectively reduce the attachment of plankton and improve its resistance to biofouling.

[0033] The carbon dots of this invention incorporate phosphate groups. The negative charge of the phosphate groups promotes the migration of photogenerated holes and adsorbs oxygen, thereby enhancing the generation capacity of reactive oxygen species. Furthermore, the phosphate, carboxyl, and hydroxyl functional groups on the carbon dot surface can exhibit strong chelation with Fe²⁺ / Fe³⁺ dissolved from the stainless steel substrate surface, thus strengthening the bond between the coating and the substrate.

[0034] Grafting of polyaniline-polyacrylate copolymers can significantly improve the compatibility of basalt flake-carbon dot composites with resin systems in coatings, enhance the dispersibility of the basalt flake-carbon dot composites, and reduce their aggregation. In this copolymer: (1) Polyaniline can exert excellent anti-corrosion and strengthening effects. Its anti-corrosion mechanism is as follows: Polyaniline is a conjugated polymer with redox ability. Since the reduction potential of polyaniline is 0V / SCE, while the oxidation potential of metal Fe is -0.7V / SCE, when it comes into contact with metal iron, a redox reaction occurs with the participation of water and oxygen, and a dense metal oxide γ-Fe2O3 is formed at the interface, which prevents the metal from being further oxidized, that is, the metal is passivated, thereby achieving the anti-corrosion effect (Suo Longning, Shang Xiuli, Zhou Cuiwen, et al. Application of polyaniline anti-corrosion coating in metal protection [J]. China Building Materials Science and Technology, 2013(2):4.DOI:10.3969 / j.issn.1003-8965.2013.02.020.). The γ-Fe2O3 generated under the action of polyaniline can enhance the photoactive oxygen performance of carbon dots to a certain extent. The mechanism may include: (1) γ-Fe2O3 easily forms oxygen vacancies, which serve as active sites for adsorbing and activating O2, reducing the O2 reduction energy barrier and promoting the formation of singlet oxygen (¹O2) or ·O2 under carbon dot illumination. -(2) The Fe³⁺ / Fe²⁺ redox cycle in γ-Fe₂O₃ can accelerate electron transfer, thereby improving the efficiency of active oxygen generation; (3) γ-Fe₂O₃ and carbon dots can form a heterojunction, which allows electrons generated by carbon dots under illumination to migrate to γ-Fe₂O₃ and holes to remain in carbon dots, significantly inhibiting the recombination of photogenerated electrons and holes, prolonging the carrier lifetime, thereby improving the efficiency of photogenerated electrons in generating active oxygen.

[0035] (2) Polyacrylate has good compatibility with waterborne polyurethane and waterborne silicone acrylate in the coating system, which can make up for the poor compatibility of polyaniline with waterborne polyurethane and waterborne silicone acrylate. At the same time, polyacrylate can also improve the coating's resistance to ultraviolet aging, yellowing, water resistance and weather resistance. It can also improve film-forming properties and flexibility. The acrylate segments have strong adhesion to the substrate, which is beneficial to enhance the adhesion of the coating.

[0036] Release-type rust-inhibiting and reinforcing particles can continuously release the rust-inhibiting functional component zinc ammonium phosphate, while the corrosion-modified lamellar filler provides excellent physical barrier and corrosion resistance enhancement effects. The two work together to significantly improve the corrosion resistance of the coating.

[0037] 3. Waterborne polyurethane resin, water-soluble silicone-acrylic resin Waterborne polyurethane resin-based coatings have advantages such as good environmental performance, strong adhesion, and excellent corrosion and wear resistance. Water-soluble silicone acrylic resin has the characteristics of low surface energy, excellent weather resistance and hydrophobicity. By compounding waterborne polyurethane resin and water-soluble silicone acrylic resin to prepare coatings, the advantages of both can be combined to obtain good anti-corrosion and reinforcement effects.

[0038] The above is the general concept of the present invention. Based on this, detailed embodiments and comparative examples are provided below to further illustrate the present invention.

[0039] The following is a partial description of the raw materials used: The waterborne polyurethane resin is HK7080, manufactured by Nantong Runfeng Petrochemical Co., Ltd.; the water-soluble silicone-acrylic resin is LB-2818, brand Lanbo, manufactured by Shenzhen Lanbo Environmental Protection Technology Co., Ltd.; the dispersant is BYK-163; the adhesion promoter is γ-aminopropyltriethoxysilane; the film-forming aid is propylene glycol butyl ether; the defoamer is Walker VOK-MD20; the curing agent is an isocyanate curing agent, specifically Covestro Desmodur N3300; the basalt flakes, with a size of 20-50μm and an average thickness of approximately 3μm, are manufactured by Zhongxian New Material Technology (Chengde) Co., Ltd.

[0040] Preparation Example 1: Preparation of slow-release rust-inhibiting and reinforcing particles: 1-1) Zinc ammonium phosphate was loaded onto mesoporous alumina to prepare zinc ammonium phosphate-mesoporous alumina composite particles: 10g of mesoporous alumina and 0.5g of PEG600 (surfactant) were added to 500mL of deionized water and ultrasonically dispersed for 1h. Then, 3.2g of zinc sulfate was added, stirred for 30min, and allowed to stand for 1h. Then, 2.7g of diammonium hydrogen phosphate was added, and the pH was adjusted to 9 with 20wt% ammonia. The mixture was stirred at 50℃ for 12h, aged at room temperature for 12h, centrifuged, and the solid was washed with ethanol until neutral. It was then dried at 100℃ to obtain zinc ammonium phosphate-mesoporous alumina composite particles. 1-2) Surface modification of zinc ammonium phosphate-mesoporous alumina composite particles using silane coupling agent KH570: Take 5g of zinc ammonium phosphate-mesoporous alumina composite particles and 20mL of deionized water and add them to 160mL of ethanol. Stir for 90min, then add 1.8g of silane coupling agent KH570 dropwise. Stir and react at 80℃ for 10h. Filter, wash the solid with ethanol, and dry under vacuum at 80℃ to obtain slow-release rust-inhibiting and reinforcing particles.

[0041] Figure 1 The infrared absorption spectra of the zinc ammonium phosphate-mesoporous alumina composite particles prepared in Example 1 above are shown at 3300 and 1485 cm⁻¹. -1 The nearby peaks originate from the N–H stretching and bending vibrations of NH4+; the peaks near 1100 and 440 cm⁻¹ originate from the P–O stretching and bending vibrations in the phosphorus-oxygen tetrahedron, indicating that zinc ammonium phosphate was successfully synthesized on mesoporous alumina.

[0042] Preparation Example 2: Preparation of Corrosion-Resistant Modified Laminated Packing Material: Preparation Example 2-1 Corrosion-resistant modified lamellar packing A1: 2-1) Basalt flake pretreatment: Add 5g of basalt flakes to 400mL of 5mol / L hydrochloric acid, stir and reflux at 70℃ for 20h, filter, wash with deionized water, and dry. 2-2) In-situ synthesis of carbon dots on pretreated basalt flakes: 3g of pretreated basalt flakes and 30mL of ethanol were added to 100mL of deionized water and ultrasonically dispersed for 40min. Then, 0.61g of sodium hexametaphosphate, 1.2g of citric acid, 0.36g of α-phenylethylamine and 0.24g of urea were added and stirred for 20min. The resulting mixture was transferred to a reaction vessel and reacted at 180℃ for 24h. After cooling, the mixture was filtered. The solid was washed with deionized water and vacuum dried at 90℃ for 12h to obtain the basalt flake-carbon dot composite. 2-3) Surface modification of basalt flake-carbon dot composites using silane coupling agent KH570: Take 3g of basalt flake-carbon dot composite and 15mL of deionized water and add them to 100mL of ethanol. Stir for 1h, then add 1.4g of silane coupling agent KH570 dropwise. Stir and react at 80℃ for 10h. Filter, wash the solid with ethanol, and dry under vacuum at 80℃ to obtain the modified basalt flake-carbon dot composite. 2-4) Grafting polyaniline-polyacrylate copolymer onto modified basalt flake-carbon dot composite: 2-4-1) Take 3g of modified basalt flake-carbon point complex and 1.4g of sodium dodecylbenzenesulfonate and add them to 120mL of deionized water. Disperse by ultrasonication for 45min. Then add 2g of acrylic acid, 1.5g of hydroxyethyl acrylate and 4g of methyl methacrylate. Stir under nitrogen for 30min and then add 15mL of initiator aqueous solution containing 0.075g of ammonium persulfate. Stir and react at 70℃ for 2h. 2-4-2) Cool to room temperature, add 7.5g aniline, stir for 10min, add 15mL of initiator aqueous solution containing 0.075g ammonium persulfate, stir and react at room temperature for 24h, filter, wash the solid with deionized water, and dry under vacuum at 70℃ to obtain corrosion-resistant modified sheet packing, denoted as corrosion-resistant modified sheet packing A1.

[0043] Figure 2 The infrared absorption spectrum of the basalt flake-carbon dot composite prepared in Example 2-1 shows that the characteristic peaks of carboxyl, amino, and hydroxyl groups mainly originate from carbon dots, indicating that carbon dots were successfully deposited on basalt flakes.

[0044] Preparation Example 2-2 Corrosion-resistant modified lamellar packing A2: 2-1) Basalt flake pretreatment: Add 5g of basalt flakes to 400mL of 5mol / L hydrochloric acid, stir and reflux at 70℃ for 20h, filter, wash with deionized water, and dry. 2-2) Surface modification of basalt flakes using silane coupling agent KH570: Take 3g of basalt flakes and 15mL of deionized water and add them to 100mL of ethanol. Stir for 1h, then add 1.4g of silane coupling agent KH570 dropwise. Stir and react at 80℃ for 10h. Filter, wash the solid with ethanol, and dry under vacuum at 80℃ to obtain modified basalt flakes. 2-4) Grafting polyaniline-polyacrylate copolymer onto modified basalt flakes: 2-4-1) Take 3g of modified basalt flakes and 1.4g of sodium dodecylbenzenesulfonate and add them to 120mL of deionized water. Disperse them by sonication for 45min. Then add 2g of acrylic acid, 1.5g of hydroxyethyl acrylate and 4g of methyl methacrylate. Stir with nitrogen gas for 30min and then add 15mL of initiator aqueous solution containing 0.075g of ammonium persulfate. Stir and react at 70℃ for 2h. 2-4-2) Cool to room temperature, add 7.5g aniline, stir for 10min, add 15mL of initiator aqueous solution containing 0.075g ammonium persulfate, stir and react at room temperature for 24h, filter, wash the solid with deionized water, and dry under vacuum at 70℃ to obtain corrosion-resistant modified sheet packing, denoted as corrosion-resistant modified sheet packing A2.

[0045] Preparation Example 2-3 Corrosion-resistant modified lamellar packing A3: The only difference between this and the corrosion-resistant modified sheet filler A1 is that sodium hexametaphosphate is not added in step 2-2, and the amount of citric acid added is modified to 1.8g.

[0046] Preparation Example 2-4 Corrosion-resistant modified lamellar packing A4: The only difference between this and the corrosion-modified lamellar packing A1 is: Steps 2-4 in this example are as follows: 2-4-1) Take 3g of modified basalt flake-carbon point composite and 1.4g of sodium dodecylbenzenesulfonate and add them to 120mL of deionized water. Disperse by ultrasonication for 45min. Then add 4.5g of acrylic acid, 3g of hydroxyethyl acrylate and 7g of methyl methacrylate. Stir with nitrogen gas for 30min and then add 30mL of initiator aqueous solution containing 0.15g of ammonium persulfate. Stir and react at 70℃ for 8h. Filter, wash the solid with deionized water and dry it under vacuum at 70℃ to obtain corrosion-resistant modified sheet packing, which is denoted as corrosion-resistant modified sheet packing A4.

[0047] Example 1 A surface anti-corrosion treatment process for stainless steel pipes includes the following steps: S1. Pretreatment: After mechanical polishing, the stainless steel pipe is placed in a degreasing solution and soaked for 20 minutes before being taken out and rinsed with water. The degreasing solution comprises the following components: 500L water, 12kg sodium hydroxide, 25kg sodium phosphate, 5kg sodium gluconate, and 0.75kg fatty alcohol polyoxyethylene ether (AEO-7). S2. Pickling: Place the pretreated stainless steel pipe in acid solution, soak it at room temperature for 5 minutes, and then take it out and wash it with water. The solvent in the acid solution is deionized water, and the acid solution includes the following components: sulfuric acid 60 g / L, phosphoric acid 20 g / L; S3. Passivation: Immerse the pickled stainless steel pipe in the passivation solution at 45°C for 30 minutes, then remove it, wash it with water, and dry it. The passivation solution comprises the following components: 500L water, 18kg sodium silicate, 10L hydrogen peroxide with a concentration of 15wt%, 6kg citric acid, and 2L phosphoric acid with a concentration of 80wt%. S4. Apply a composite anti-corrosion and reinforcing coating to the outer surface of the passivated stainless steel pipe, with a coating amount of 240g / m. 2After coating, cure at 80℃ for 2 hours to complete the anti-corrosion treatment.

[0048] The composite anti-corrosion reinforced coating includes the following components by weight: The mixture contains 42 parts of waterborne polyurethane resin, 58 parts of water-soluble silicone-acrylic resin, 14 parts of slow-release rust-inhibiting reinforcing particles, 16 parts of anti-corrosion modified lamellar filler, 17 parts of curing agent, 2.5 parts of dispersant, 1.8 parts of adhesion promoter, 2 parts of film-forming aid, 0.5 parts of defoamer, and 40 parts of deionized water. The preparation method of composite anti-corrosion and reinforced coating is as follows: water-based polyurethane resin, water-soluble silicone acrylic resin, slow-release anti-rust reinforcing particles, anti-corrosion modified lamellar filler, dispersant, adhesion promoter, film-forming aid, defoamer, and deionized water are mixed evenly. Before use, a curing agent is added and then stirred evenly to obtain composite anti-corrosion and reinforced coating.

[0049] The corrosion-resistant modified sheet packing in this example is corrosion-resistant modified sheet packing A1.

[0050] Example 2 This example is basically the same as Example 1; the differences are listed below: The composite anti-corrosion reinforced coating in this example comprises the following components by weight: The mixture contains 40 parts of waterborne polyurethane resin, 60 parts of water-soluble silicone-acrylic resin, 12.5 parts of slow-release rust-inhibiting reinforcing particles, 14 parts of anti-corrosion modified lamellar filler, 17 parts of curing agent, 2.5 parts of dispersant, 1.8 parts of adhesion promoter, 2 parts of film-forming aid, 0.5 parts of defoamer, and 40 parts of deionized water.

[0051] Example 3 This example is basically the same as Example 1; the differences are listed below: The composite anti-corrosion reinforced coating in this example comprises the following components by weight: The mixture contains 45 parts of waterborne polyurethane resin, 55 parts of water-soluble silicone-acrylic resin, 14 parts of slow-release rust-inhibiting reinforcing particles, 16 parts of anti-corrosion modified lamellar filler, 18 parts of curing agent, 2.5 parts of dispersant, 1.8 parts of adhesion promoter, 1.5 parts of film-forming aid, 0.5 parts of defoamer, and 40 parts of deionized water.

[0052] Comparative Example 1 This example is basically the same as Example 1, and the only difference is listed below: the composite anti-corrosion and reinforcing coating in this example does not contain slow-release rust-inhibiting particles.

[0053] Comparative Example 2 This example is basically the same as Example 1; the differences are listed below: The composite anti-corrosion reinforced coating in this example comprises the following components by weight: 42 parts of waterborne polyurethane resin, 58 parts of water-soluble silicone acrylic resin, 4 parts of zinc ammonium phosphate (purchased from Shandong Xinshunli Chemical Technology Co., Ltd.), 16 parts of anti-corrosion modified lamellar filler, 17 parts of curing agent, 2.5 parts of dispersant, 1.8 parts of adhesion promoter, 2 parts of film-forming aid, 0.5 parts of defoamer, and 40 parts of deionized water.

[0054] The preparation method of composite anti-corrosion and reinforced coating is as follows: water-based polyurethane resin, water-soluble silicone acrylic resin, zinc ammonium phosphate, anti-corrosion modified lamellar filler, dispersant, adhesion promoter, film-forming aid, defoamer, and deionized water are mixed evenly. Before use, a curing agent is added and then stirred evenly to obtain composite anti-corrosion and reinforced coating.

[0055] Comparative Example 3 This example is basically the same as Example 1, and the only difference is listed below: no anti-corrosion modified lamellar filler is added to the composite anti-corrosion reinforced coating in this example.

[0056] Comparative Example 4 This example is basically the same as Example 1. The only difference is listed below: the corrosion-resistant modified sheet packing in this example is corrosion-resistant modified sheet packing A2.

[0057] Comparative Example 5 This example is basically the same as Example 1, and the only difference is listed below: the corrosion-resistant modified sheet packing in this example is corrosion-resistant modified sheet packing A3.

[0058] Comparative Example 6 This example is basically the same as Example 1. The only difference is listed below: the corrosion-resistant modified sheet packing in this example is corrosion-resistant modified sheet packing A4.

[0059] Comparative Example 7 This example is basically the same as Example 1, and the only difference is listed below: The anti-corrosion modified lamellar filler in this example is the modified basalt flake-carbon dot composite prepared in Preparation Example 2-1, that is, this example does not perform polyaniline-polyacrylate copolymer grafting treatment on the modified basalt flake-carbon dot composite.

[0060] Performance testing 1. Corrosion resistance Q235 steel plates were used as samples, with sample dimensions of 150mm × 100mm × 1mm. The composite anti-corrosion reinforced coatings prepared in each example were applied to all surfaces of the samples. After coating, the coating was cured at 80℃ for 2 hours, and then cured at room temperature for 12 hours to form a 0.1mm thick coating (all surfaces were required to be completely coated without cracks). The obtained test samples were subjected to the neutral salt spray test according to standard GB / T10125-2021 "Artificial Atmosphere Corrosion Test - Salt Spray Test", with a temperature of 35℃, sodium chloride solution concentration of 55g / L, pH=6.5, and an experimental time of 96 hours. The weight loss of the test samples after the experiment was measured. The test results are shown in Table 1 below: Table 1 The test results show that Examples 1-3 have excellent anti-corrosion performance. The results of Comparative Example 1 indicate that the slow-release rust-inhibiting reinforcing particles in the coating can effectively improve anti-corrosion performance. The results of Comparative Example 2 indicate that the composite structure formed by loading zinc ammonium phosphate onto mesoporous alumina composite particles can improve anti-corrosion performance. The results of Comparative Example 3 indicate that the anti-corrosion modified lamellar filler in the coating can effectively improve anti-corrosion performance. The results of Comparative Example 6 indicate that polyaniline in the polyaniline-polyacrylate copolymer has a promoting effect on improving anti-corrosion performance. The decrease in anti-corrosion performance in Comparative Example 7 is attributed to the absence of polyaniline and the failure to graft polyaniline-polyacrylate copolymer onto the anti-corrosion modified lamellar filler, which led to a decrease in the dispersion performance of the filler.

[0061] 2. Adhesion The composite anti-corrosion reinforced coatings prepared in each example were applied to Q235 steel plates, cured at 80℃ for 2 hours, and then cured at room temperature for 12 hours to form a coating with a thickness of 0.1 mm. The adhesion of the coating was tested according to standard GB / T 5210. The test results are shown in Table 2 below: Table 2 The test results show that the coatings in Examples 1-3 have strong adhesion. The results of Comparative Examples 1 and 3 indicate that the slow-release rust-inhibiting particles and the anti-corrosion modified lamellar filler in the coating can both improve the adhesion of the coating. The results of Comparative Example 4 show that the carbon dots deposited in the anti-corrosion modified lamellar filler also have a certain enhancing effect on the adhesion of the coating.

[0062] 3. Antibacterial properties (1) The composite anti-corrosion reinforcing coatings prepared in each example were coated onto the surface of the substrate (PET film material), cured at 80°C for 2 hours, and then cured at room temperature for 12 hours to form a coating with a thickness of 0.1 mm, thus obtaining the test sample. The test sample was cut into 4 mm circular specimens. Escherichia coli ATCC8739The sample was inoculated into nutrient agar medium, spread evenly, and then a circular sample was placed in the center of the medium. Under fluorescent light, it was incubated for 48 hours (37℃). The diameter of the inhibition zone was measured using the cross-hatching method to evaluate the antibacterial performance of the coating. The test results are shown in Table 3 below: Table 3 The test results show that the coatings in Examples 1-3 have excellent antibacterial properties. The results of Comparative Example 1 indicate that the slow-release rust-inhibiting reinforcing particles also have a certain antibacterial effect, which may be attributed to the slow release of zinc ions by the zinc ammonium phosphate. The results of Comparative Examples 3 and 4 show that the corrosion-modified lamellar filler can improve the antibacterial properties of the coating, mainly through the contribution of carbon dots deposited on the corrosion-modified lamellar filler. The results of Comparative Example 5 show that the introduction of phosphate ions into the carbon dots can enhance the antibacterial ability.

[0063] (2) Antibacterial principle test: Antiseptic modified sheet filler A1 (hereinafter referred to as filler A1) and antiseptic modified sheet filler A2 (hereinafter referred to as filler A2) were added to deionized water and ultrasonically dispersed for 30 min to prepare the test solution. The ability of the test solution to generate active oxygen under fluorescent lamp (100W) irradiation was detected by a singlet oxygen fluorescent probe.

[0064] Figure 3 The test results show that higher fluorescence intensity indicates higher reactive oxygen species content. The test results indicate that both filler A1 and filler A2 can generate reactive oxygen species under light irradiation, and the generation of reactive oxygen species is the main source of antibacterial ability. However, the reactive oxygen species generation efficiency of filler A1 is higher than that of filler A2, indicating that the introduction of phosphate groups into carbon dots can enhance the generation of reactive oxygen species.

[0065] 4. Anti-fouling test The test was conducted according to standard GB / T 5370-2007 "Test Method for Shallow Sea Immersion of Antifouling Paint Samples", with a test cycle of 12 months. The percentage of biofouled area on the sample was measured, i.e., the percentage of biofouled area (%). The test results are shown in Table 4 below: Table 4 The test results show that Examples 1-3 have excellent anti-biofouling ability, and the results are consistent with the antibacterial performance test results.

[0066] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details.

Claims

1. A surface anti-corrosion treatment process for stainless steel pipes, characterized in that, Includes the following steps: S1. Pretreatment: The stainless steel pipe is mechanically polished and then degreased. S2. Pickling: The pretreated stainless steel pipe is placed in acid solution for pickling. S3. Passivation: The pickled stainless steel pipe is placed in a passivation solution for passivation treatment. S4. Apply a composite anti-corrosion and reinforcing coating to the outer surface of the passivated stainless steel pipe, cure it, and complete the anti-corrosion treatment. The composite anti-corrosion and reinforcing coating comprises the following components in parts by weight: The ingredients are: 30-55 parts waterborne polyurethane resin, 45-70 parts water-soluble silicone-acrylic resin, 8-16 parts slow-release rust-inhibiting reinforcing particles, 10-32 parts anti-corrosion modified lamellar filler, 10-25 parts curing agent, 1.5-4 parts dispersant, 0.9-3.5 parts adhesion promoter, 1-4 parts film-forming aid, 0.5-1 parts defoamer, and 30-50 parts deionized water. The slow-release rust-preventive reinforcing particles are prepared by the following method: 1-1) Zinc ammonium phosphate was loaded onto mesoporous alumina to obtain zinc ammonium phosphate-mesoporous alumina composite particles; 1-2) Surface modification of zinc ammonium phosphate-mesoporous alumina composite particles was carried out using silane coupling agents to obtain slow-release rust-preventing and reinforcing particles; The corrosion-resistant modified sheet filler is prepared by the following method: 2-1) Pretreatment of basalt flakes; 2-2) Carbon dots were synthesized in situ on pretreated basalt flakes to obtain basalt flake-carbon dot composites; 2-3) The surface of the basalt flake-carbon dot composite was modified by using a silane coupling agent to obtain the modified basalt flake-carbon dot composite. 2-4) Grafting polyaniline-polyacrylate copolymer onto modified basalt flake-carbon dot composite yields corrosion-resistant modified sheet filler.

2. The anti-corrosion treatment process for stainless steel pipe surface according to claim 1, characterized in that, in, The degreasing solution comprises the following components: water, sodium hydroxide, sodium phosphate, sodium gluconate, and fatty alcohol polyoxyethylene ether; the passivation solution comprises the following components: water, sodium silicate, hydrogen peroxide, citric acid, and phosphoric acid.

3. The anti-corrosion treatment process for stainless steel pipe surface according to claim 2, characterized in that, Includes the following steps: S1. Pretreatment: After mechanical polishing, the stainless steel pipe is placed in a degreasing solution and soaked for 10-40 minutes before being taken out and rinsed with water. The degreasing solution comprises the following components by weight: 250-1000 parts water, 6-24 parts sodium hydroxide, 12-40 parts sodium phosphate, 2-10 parts sodium gluconate, and 0.5-1.5 parts fatty alcohol polyoxyethylene ether. S2. Pickling: Place the pretreated stainless steel pipe in acid solution, soak for 2-10 minutes, then take it out and wash with water. The solvent in the acid solution is deionized water, and the acid solution includes the following components: sulfuric acid 30-90 g / L, phosphoric acid 10-40 g / L; S3. Passivation: Immerse the pickled stainless steel pipe in the passivation solution at 35-60℃ for 15-60 minutes, then take it out, wash it with water, and dry it. The passivation solution includes the following components: 250-1000L of water, 9-36kg of sodium silicate, 5-20L of hydrogen peroxide with a concentration of 10-20wt%, 3-12kg of citric acid, and 1-4L of phosphoric acid with a concentration of 60-85wt%. S4. Apply a composite anti-corrosion and reinforcing coating to the outer surface of the passivated stainless steel pipe, with a coating amount of 150-300 g / m. 2 After coating, cure at 70-90℃ for 1-4 hours to complete the anti-corrosion treatment.

4. The anti-corrosion treatment process for stainless steel pipe surface according to claim 1, characterized in that, The silane coupling agent used in steps 1-2) and 2-3) is KH570.

5. The anti-corrosion treatment process for stainless steel pipe surface according to claim 1, characterized in that, The slow-release rust-inhibiting and reinforcing particles were prepared by the following method: 1-1) Mesoporous alumina and surfactant were added to deionized water, ultrasonically dispersed, and then zinc sulfate was added. After stirring and standing, diammonium hydrogen phosphate was added, the pH was adjusted to 8-10, and the reaction was carried out under heating and stirring. After aging, centrifugation, solid washing and drying were performed to obtain zinc ammonium phosphate-mesoporous alumina composite particles. 1-2) Take zinc ammonium phosphate-mesoporous alumina composite particles and deionized water, add them to ethanol, stir, add silane coupling agent KH570 dropwise, stir and react under heating, filter, wash and dry the solid to obtain slow-release rust-preventing and reinforcing particles.

6. The anti-corrosion treatment process for stainless steel pipe surface according to claim 5, characterized in that, The surfactant used in step 1-1) is one or more of PEG 400, PEG 600, PEG 1000, PEG 2000 and PEG 4000.

7. The anti-corrosion treatment process for stainless steel pipe surface according to claim 6, characterized in that, The slow-release rust-inhibiting and reinforcing particles were prepared by the following method: 1-1) Zinc ammonium phosphate was loaded onto mesoporous alumina to prepare zinc ammonium phosphate-mesoporous alumina composite particles: Add 5-20g of mesoporous alumina and 0.25-1g of PEG 600 to 250-1000mL of deionized water and sonicate for 0.5-2h. Then add 1.6-6.4g of zinc sulfate, stir for 15-60min, and let stand for 0.5-2h. Then add 1.3-5.5g of diammonium hydrogen phosphate, adjust the pH to 8-10 with ammonia, stir and react at 40-55℃ for 6-24h, age at room temperature for 8-30h, centrifuge, wash the solid with ethanol until neutral, and dry to obtain zinc ammonium phosphate-mesoporous alumina composite particles. 1-2) Surface modification of zinc ammonium phosphate-mesoporous alumina composite particles using silane coupling agent KH570: Take 2.5-10g of zinc ammonium phosphate-mesoporous alumina composite particles and 10-40mL of deionized water and add them to 80-350mL of ethanol. Stir for 45-180min, then add 0.9-3.6g of silane coupling agent KH570 dropwise. Stir and reflux at 70-90℃ for 6-24h, filter, wash the solid with ethanol, and vacuum dry to obtain slow-release rust-inhibiting and reinforcing particles.

8. The anti-corrosion treatment process for stainless steel pipe surface according to claim 1, characterized in that, The corrosion-resistant modified sheet filler is prepared by the following method: 2-1) Basalt flake pretreatment: Add basalt flakes to hydrochloric acid, heat and stir under reflux, filter, wash and dry; 2-2) Pretreated basalt flakes and ethanol were added to deionized water, ultrasonically dispersed, and then sodium hexametaphosphate, citric acid, α-phenylethylamine and urea were added. The mixture was stirred and transferred to a reaction vessel. The mixture was heated and reacted, cooled, filtered, and the solid was washed and dried to obtain basalt flake-carbon dot composite. 2-3) Take basalt flake-carbon dot composite and deionized water and add them to ethanol. After stirring for 1 minute, add silane coupling agent KH570 dropwise, heat and stir to react, filter, wash and dry the solid to obtain modified basalt flake-carbon dot composite. 2-4) Grafting polyaniline-polyacrylate copolymer onto modified basalt flake-carbon dot composite: 2-4-1) Add modified basalt flake-carbon point complex and sodium dodecylbenzenesulfonate to deionized water, disperse by ultrasonication, add acrylic acid, hydroxyethyl acrylate and methyl methacrylate, stir with nitrogen gas, add initiator aqueous solution dropwise, and stir under heating to react; 2-4-2) Cool, add aniline, stir, add initiator aqueous solution dropwise, stir and react at room temperature, filter, wash and dry the solid to obtain corrosion-resistant modified sheet packing.

9. The anti-corrosion treatment process for stainless steel pipe surface according to claim 1, characterized in that, The corrosion-resistant modified sheet filler is prepared by the following method: 2-1) Basalt flake pretreatment: Add 2.5-10g of basalt flakes to 200-800mL of hydrochloric acid with a concentration of 2-8mol / L, stir and reflux at 60-80℃ for 10-36h, filter, wash with deionized water, and dry. 2-2) In-situ synthesis of carbon dots on pretreated basalt flakes: 1.5-6 g of pretreated basalt flakes and 15-60 mL of ethanol were added to 50-200 mL of deionized water and ultrasonically dispersed for 20-60 min. Then, 0.3-1.22 g of sodium hexametaphosphate, 0.6-2.4 g of citric acid, 0.18-0.72 g of α-phenylethylamine, and 0.12-0.48 g of urea were added and stirred for 10-40 min. The resulting mixture was transferred to a reaction vessel and reacted at 160-200 °C for 12-48 h. After cooling, the mixture was filtered, the solid was washed with deionized water, and dried under vacuum to obtain the basalt flake-carbon dot composite. 2-3) Surface modification of basalt flake-carbon dot composites using silane coupling agent KH570: Take 1.5-6g of basalt flake-carbon dot composite and 7-30mL of deionized water and add them to 50-200mL of ethanol. Stir for 0.5-2h, then add 0.7-2.8g of silane coupling agent KH570 dropwise. Stir and react at 65-90℃ for 6-24h. Filter, wash the solid with ethanol, and dry under vacuum to obtain the modified basalt flake-carbon dot composite. 2-4) Grafting polyaniline-polyacrylate copolymer onto modified basalt flake-carbon dot composite: 2-4-1) Take 1.5-6g of modified basalt flake-carbon point composite and 0.7-2.8g of sodium dodecylbenzenesulfonate and add them to 60-240mL of deionized water. Disperse by ultrasonication for 30-90min. Then add 1-4g of acrylic acid, 0.75-3g of hydroxyethyl acrylate and 2-8g of methyl methacrylate. Stir under nitrogen for 15-60min and then add 10-30mL of initiator aqueous solution containing 0.05-0.15g of ammonium persulfate. Stir and react at 60-85℃ for 1-4h. 2-4-2) Cool to room temperature, add 3.5-15g aniline, stir for 5-20min, add 10-30mL of initiator aqueous solution containing 0.05-0.15g ammonium persulfate, stir and react at room temperature for 12-36h, filter, wash the solid with deionized water, and vacuum dry to obtain corrosion-resistant modified sheet packing.

10. The anti-corrosion treatment process for stainless steel pipe surface according to claim 1, characterized in that, The composite anti-corrosion and reinforcing coating comprises the following components in parts by weight: The mixture contains 42 parts of waterborne polyurethane resin, 58 parts of water-soluble silicone-acrylic resin, 14 parts of slow-release rust-inhibiting reinforcing particles, 16 parts of anti-corrosion modified lamellar filler, 17 parts of curing agent, 2.5 parts of dispersant, 1.8 parts of adhesion promoter, 2 parts of film-forming aid, 0.5 parts of defoamer, and 40 parts of deionized water.

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