Preparation method and application of modified carbon nanofiber for metal anticorrosive paint
Nickel/nickel sulfide modified carbon nanofibers were prepared by hydrothermal method and photocatalytic reduction, which solved the problem of poor compatibility between carbon nanofibers and resin matrix, improved the anti-corrosion and anti-fouling performance of coating, and extended the service life of coating.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-26
- Publication Date
- 2026-04-03
AI Technical Summary
The lack of active functional groups on the surface of existing carbon nanofibers results in poor compatibility and interfacial bonding strength with the resin matrix, leading to defects in the coating during service in marine environments and affecting its protective function and lifespan.
Nickel sulfide modified carbon nanofibers were prepared by hydrothermal method, and partially reduced nickel/nickel sulfide modified carbon nanofibers were prepared by photocatalytic reduction method to increase their interfacial compatibility with resin matrix and add them as functional nanofillers to organic coatings.
It improves the density and anti-corrosion and anti-fouling properties of the coating, slows down the penetration of corrosive media such as water, oxygen, and chloride ions, and enhances the protective function and lifespan of the coating.
Smart Images
Figure CN121781405A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of nanofiber reinforced composite coating technology, specifically relating to a method for preparing and applying nickel / nickel sulfide modified carbon nanofibers for metal anti-corrosion coatings. Background Technology
[0002] Marine engineering equipment and infrastructure inevitably encounter two major problems during long-term service in the marine environment: corrosion damage and biofouling. In the marine environment, the essence of material corrosion damage is electrochemical corrosion. Its mechanism is that corrosive factors such as water, oxygen, and chloride ions penetrate to the material surface under the coupled effect of multiple marine environmental factors, resulting in electrochemical corrosion and chloride ion corrosion.
[0003] Marine corrosion protection primarily explores protective measures from the perspectives of dissolved oxygen, marine microorganisms, salinity, and temperature. Different countries have different technical characteristics and development paths in anti-corrosion coatings, but the commonality lies in organic coatings. Furthermore, biofouling is ubiquitous on the surfaces of all facilities in the marine environment, including large offshore platforms, ships, aquaculture cages, pipelines, and submarine cables. Biofouling organisms are heavy and difficult to remove when wet, and the problem has become a key factor restricting the development of the marine economy. The hazards of marine biofouling include: increased drag on ships; damage to surface coatings of marine facilities by attached organisms; the secretion of large amounts of acidic substances during the growth of biofouling organisms that corrode metals, accelerating the corrosion of ships and other marine equipment; increased noise during navigation for submarines, underwater vehicles, and other underwater navigation equipment due to biofouling, leading to decreased stealth performance and increased visibility; and malfunction of instruments, rotating mechanisms, and acoustic instruments.
[0004] Fiber-reinforced polymer coatings are widely used in marine corrosion protection due to their low cost and excellent chemical stability and mechanical properties. However, the lack of active functional groups on the surface of carbon nanofibers results in poor compatibility and interfacial bonding strength with the resin matrix, which may lead to internal defects in the coating. Multiple factors indicate that the metal / coating interface and the filler / resin interface are the weak points of the coating system in marine environments; damage to these interfaces directly affects the coating's protective function and lifespan. Therefore, reducing inherent defects in the coating and promptly repairing defects and damage that occur during service are crucial for achieving long-term corrosion protection for marine engineering metal materials.
[0005] To address the aforementioned challenges, Ni nanoparticles obtained through in-situ growth of NiS nanosheets and photocatalytic reduction of carbon nanofibers were used to modify the carbon nanofibers, improving their interfacial compatibility with the resin matrix and imparting antibacterial properties to the material. The introduction of Ni nanoparticles can better fill the tiny gaps between CNFs and the polymer matrix, resulting in higher coating density and further delaying the penetration of corrosive media such as water, oxygen, and chloride ions. Compared to other composite coating preparation methods, the method proposed in this invention comprehensively improves the overall performance of the composite coating in terms of mechanical properties, corrosion resistance, and biofouling resistance. Summary of the Invention
[0006] In order to overcome the above-mentioned shortcomings of the prior art, the present invention proposes a method for preparing nickel / nickel sulfide modified carbon nanofibers for metal anti-corrosion coatings and their application.
[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for preparing modified carbon nanofibers for metal anti-corrosion coatings includes the following steps: S1, nickel nitrate hexahydrate (Ni(NO3)2·6H2O) and thioacetamide (CH3CSNH2) were added to deionized water and stirred until completely dissolved to obtain mixed solution A; carbon nanofibers were added to mixed solution A and ultrasonically dispersed to obtain mixed solution B; mixed solution B was subjected to a hydrothermal reaction; after cooling to room temperature, it was washed and dried to obtain nickel sulfide modified carbon nanofibers (NiS-CNFs). S2, the nickel sulfide modified carbon nanofibers are added to an ethanol aqueous solution, ultrasonically dispersed, and then high-purity nitrogen gas is introduced; after irradiation with a xenon lamp, they are filtered, washed, and dried to obtain nickel / nickel sulfide modified carbon nanofibers (NiSx-CNFs). In step S1, thioacetamide decomposes under hydrolysis conditions to produce hydrogen sulfide (H2S), and the chemical equation is (1): (1); Then hydrogen sulfide reacts with nickel nitrate to produce nickel sulfide precipitate, and the chemical equation is (2): (2); The molar ratio of nickel nitrate hexahydrate to thioacetamide is 1:(1-1.05); in the mixed solution A, the concentration of nickel nitrate hexahydrate is 100-150 mmol / L, the concentration of thioacetamide is 105-158 mmol / L; the concentration of carbon nanofiber solution is 100-1000 mg / L; and the mass ratio of nickel nitrate hexahydrate, thioacetamide, and carbon nanofiber is 276:(72-75.6):(6.7-7.3).
[0008] Preferably, the temperature of the hydrothermal reaction in step S1 is 120-180℃ (the pressure of the hydrothermal reaction is the saturated vapor pressure of the solvent at the reaction temperature), the reaction time is 0.5-6h, and the cooling method is natural cooling.
[0009] Preferably, in step S2, the concentration of the nickel sulfide modified carbon nanofibers (NiS-CNFs) in the ethanol aqueous solution is 100-1000 mg / L; and the volume ratio of deionized water to ethanol in the ethanol aqueous solution is 1:(0.5-2).
[0010] Preferably, in step S2, the power of the xenon lamp light source is 100-500W, and the irradiation time is 1-6h.
[0011] The present invention also provides nickel / nickel sulfide modified carbon nanofibers (NiSx-CNFs) prepared by the above-mentioned method for preparing modified carbon nanofibers for metal anti-corrosion coatings; and the application of the nickel / nickel sulfide modified carbon nanofibers as functional nanofillers added to the coating system of metal coatings, so that the coating has both anti-corrosion and anti-fouling functions.
[0012] The present invention also provides a method for applying the modified carbon nanofibers for metal anti-corrosion coatings, comprising the following steps: dispersing the nickel / nickel sulfide modified carbon nanofibers in the matrix resin of the metal coating, stirring thoroughly, mixing evenly with a curing agent, coating on a metal substrate, and curing to obtain a modified carbon nanofiber-reinforced metal anti-corrosion coating; preferably, the mass addition amount of the nickel / nickel sulfide modified carbon nanofibers (NiSx-CNFs) in the metal coating (including the matrix resin and the curing agent) is 0.05% to 1.25%.
[0013] The matrix resin is at least one of epoxy resin, polyurethane, acrylic resin, and silicone resin for metal coatings; in the examples of this invention, the matrix resin selected is an epoxy resin with an epoxy value of 0.38 to 0.55; the curing agent is at least one of polyamide curing agent, polyetheramine curing agent, isocyanate curing agent, and acid anhydride curing agent for metal coatings; in the examples of this invention, the curing agent selected is a polyamide curing agent with a viscosity of 4000 to 8000.
[0014] Preferably, the metal substrate includes, but is not limited to, carbon steel (e.g., Q235); the coating method includes brush coating, roller coating, dip coating, air spraying, and airless spraying, and the curing temperature of the coating is 60–180°C.
[0015] The present invention also provides the application of the modified carbon nanofiber reinforced metal anti-corrosion coating in the field of marine metal corrosion protection and / or fouling control.
[0016] Compared with the prior art, the beneficial effects of the present invention are: This invention prepares nickel sulfide modified carbon nanofibers by a hydrothermal method, and then partially reduces nickel sulfide to obtain partially reduced nickel / nickel sulfide modified carbon nanofibers by a photocatalytic reduction method. These nanofibers are then added to an organic coating system as functional nanofillers, which can make the coating have both anti-corrosion and anti-fouling functions.
[0017] This invention solves the failure problem caused by inherent defects in organic coatings during preparation and use. The constructed coating avoids the use of organic bactericides and has good anti-corrosion and anti-biofouling properties, and has important application prospects in the fields of metal corrosion protection and biofouling control in marine engineering equipment, ships and other applications. Attached Figure Description
[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Wherein: Figure 1 The images shown are scanning electron microscope (SEM) images of nickel / nickel sulfide modified carbon nanofibers from Example 1 of this invention; where (a) represents CNFs, (b) represents NiS-CNFs, and (c) represents NiSx-CNFs.
[0019] Figure 2 These are digital photographs of the salt spray resistance tests of the coatings of Embodiment 1, Comparative Example 1, and Comparative Example 2 of the present invention; wherein, (a) is Comparative Example 1, (b) is Comparative Example 2, and (c) is Embodiment 1.
[0020] Figure 3 These are fluorescence micrographs of the coatings of Examples 1, 1, and 2 of the present invention, which are used to test their resistance to biofouling. Among them, (a) is Comparative Example 1, (b) is Comparative Example 2, and (c) is Example 1. Detailed Implementation
[0021] The specific embodiments of the present invention will be further described below. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.
[0022] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, and the experimental materials used in the following embodiments are all available through conventional commercial channels.
[0023] Example 1 A method for preparing modified carbon nanofibers for metal anti-corrosion coatings includes the following steps: S1. Calculate the precursor equivalent weight of surplus NiS relative to the weight of CNFs. Add 2.76 g of nickel nitrate hexahydrate and 0.72 g of thioacetamide to 70 mL of deionized water and stir until completely dissolved to obtain mixed solution A. Add 0.07 g of carbon nanofibers to mixed solution A, stir for 5 min, and then ultrasonically disperse for 30 min to complete the suspension and homogenization of the mixture to obtain mixed solution B. Transfer mixed solution B to a 100 mL PTFE hydrothermal autoclave and carry out hydrothermal reaction at 140 °C for 30 min. After naturally cooling to room temperature, centrifuge, wash twice with water and ethanol, and dry to obtain nickel sulfide modified carbon nanofibers (NiS-CNFs). S2, NiS was prepared by in-situ photochemical deposition. X / CNFs: Take 80 mg of nickel sulfide modified carbon nanofibers from step S1 and add them to 80 mL of a 1:1 volume ratio mixture of deionized water and ethanol. After ultrasonic dispersion, bubble the resulting suspension with high-purity N2 for 40 min to remove air. Irradiate with a 300 W Xe arc lamp for 120 min at room temperature. Collect the gray-black product by filtration, wash it repeatedly with deionized water and ethanol, and dry it in a vacuum oven at 60 °C for 24 h to obtain nickel / nickel sulfide modified carbon nanofibers (NiSx-CNFs).
[0024] The application method includes the following steps: 25 mg of nickel / nickel sulfide modified carbon nanofibers obtained in step S2 are dispersed in 4 g of epoxy resin (E51) (the amount of nickel / nickel sulfide modified carbon nanofibers added is 0.5% of the total mass of the material, resin and curing agent), and ultrasonically dispersed for 30 min; 1 g of polyamide curing agent (8531, Marine Chemical Research Institute) is added, and after thorough stirring, vacuum degassing is performed for 10 min, and the mixture is brushed onto the surface of Q235 carbon steel electrode. After curing, a metal anti-corrosion coating reinforced with modified carbon nanofibers is obtained.
[0025] Example 2 The preparation method of the modified carbon nanofibers for metal anti-corrosion coating in Example 2 is exactly the same as that in Example 1.
[0026] The only difference between Example 2 and Example 1 is that in the application method, 50 mg of nickel / nickel sulfide modified carbon nanofibers are dispersed in 4 g of epoxy resin (E51), and the metal matrix is replaced by 6061 aluminum alloy instead of carbon steel. The other steps and parameters are the same as in Example 1.
[0027] Example 3 A method for preparing modified carbon nanofibers for metal anti-corrosion coatings includes the following steps: S1. Calculate the precursor equivalent weight of surplus NiS relative to the weight of CNFs. Add 2.76 g of nickel nitrate hexahydrate and 0.75 g of thioacetamide to 70 mL of deionized water and stir until completely dissolved to obtain mixed solution A. Add 0.072 g of carbon nanofibers to mixed solution A, stir for 8 min, and then ultrasonically disperse for 30 min to complete the suspension and homogenization of the mixture to obtain mixed solution B. Transfer mixed solution B to a 100 mL PTFE hydrothermal autoclave and carry out hydrothermal reaction at 150 °C for 40 min. After naturally cooling to room temperature, centrifuge, wash twice with water and ethanol, and dry to obtain nickel sulfide modified carbon nanofibers (NiS-CNFs). S2, NiS was prepared by in-situ photochemical deposition. X / CNFs: Take 80 mg of nickel sulfide modified carbon nanofibers from step S1 and add them to 120 mL of a 1:1 volume ratio of deionized water and ethanol mixture. After ultrasonic dispersion, bubble the resulting suspension with high-purity N2 for 40 min to remove air. Irradiate with a 400 W Xe arc lamp for 100 min at room temperature. Collect the gray-black product by vacuum filtration, wash it repeatedly with deionized water and ethanol, and dry it in a vacuum oven at 60 °C for 24 h to obtain nickel / nickel sulfide modified carbon nanofibers (NiSx-CNFs).
[0028] The application method includes the following steps: 35 mg of nickel / nickel sulfide modified carbon nanofibers obtained in step S2 are dispersed in 4 g of epoxy resin (E51) (the amount of nickel / nickel sulfide modified carbon nanofibers added is 0.7% of the total mass of the material, resin and curing agent), and ultrasonically dispersed for 30 min; 1 g of polyamide curing agent (8531, Marine Chemical Research Institute) is added, and after thorough stirring, vacuum degassing is performed for 10 min. The material is then sprayed onto the surface of a Q235 carbon steel electrode using air-assisted spraying. After curing, a metal anti-corrosion coating reinforced with modified carbon nanofibers is obtained.
[0029] Comparative Example 1 The preparation method of a pure epoxy resin composite coating in Comparative Example 1 includes the following steps: Accurately weigh 4g of epoxy resin (E51), then add 1g of polyamide curing agent (8531, Marine Chemical Research Institute), stir thoroughly, and then degas under vacuum for 10 minutes to obtain a pure epoxy resin composite coating.
[0030] Comparative Example 2 The preparation method of a metal anti-corrosion coating in Comparative Example 2 is as follows: Calculate the precursor equivalent weight of excess NiS relative to the weight of CNFs; add 2.76 g of nickel nitrate hexahydrate and 0.72 g of thioacetamide to 70 mL of deionized water and stir until completely dissolved to obtain mixed solution A; add 0.07 g of carbon nanofibers to mixed solution A, stir for 5 min, and then use ultrasound to disperse for 30 min to complete the suspension and homogenization of the mixture to obtain mixed solution B; transfer mixed solution B to a 100 mL PTFE hydrothermal high-pressure reactor and carry out hydrothermal reaction at 140 °C for 30 min; allow to cool naturally to room temperature, centrifuge, wash twice with water and ethanol, and dry to obtain nickel sulfide modified carbon nanofibers (NiS-CNFs).
[0031] The application method includes the following steps: accurately weigh 25mg NiS / CNFs and add them to 4g epoxy resin (E51), ultrasonically disperse for 30 min, then add 1g polyamide curing agent (8531, Marine Chemical Research Institute), stir thoroughly and then vacuum degas for 10 min to obtain a metal anti-corrosion coating.
[0032] Application Example 1 The microstructure of the modified carbon nanofiber material obtained in Example 1 was characterized: The modified carbon nanofiber material obtained in Example 1 was observed for its microstructure using an Apreo 2S HiVac scanning electron microscope. Before observation, the sample surface was sputtered with gold using a JYSC-100 ion sputtering instrument.
[0033] As can be seen from the scanning electron microscope images, compared to CNFs ( Figure 1 a), NiS-CNFs ( Figure 1 b) and NiS X -CNFs ( Figure 1 c) The surface morphology of NiS and NiS2 has changed significantly. X Nanoparticles are grown on the surface of CNTs. NiS and NiS X The nanoparticles are relatively uniform in size, approximately 200–300 nm. This facilitates the dispersion of carbon nanofiber materials in the resin matrix, thereby further improving the density of the coating.
[0034] Application Example 2 The performance of the metal anti-corrosion coatings prepared in Example 1, Comparative Example 1, and Comparative Example 2 was tested: (1) Salt spray resistance test The long-term corrosion resistance of the composite coating was studied through neutral salt spray and field exposure experiments. The salt spray test was conducted in a salt spray chamber at 35℃, using a 5wt% NaCl solution as the test medium.
[0035] The pure epoxy coating in Comparative Example 1 ( Figure 2 a) After 24 hours of testing, obvious corrosion was observed along the artificially scratched line, and the corrosion became more severe over time (the corroded area reached 41.46 cm²). 2 Therefore, pure epoxy coatings have poor long-term corrosion resistance.
[0036] Comparative Example 2: NiS-CNFs coating ( Figure 2 b) and NiS of Example 1 X -CNFs coating ( Figure 2 c) Slight corrosion products were observed at the artificially scratched areas after 300 hours of testing. However, the NiS-CNFs coating in Comparative Example 2 showed a significant decrease in corrosion resistance after 600 hours of testing, with a corrosion area reaching 23.19 cm². 2 However, in Example 1, after 600 hours of testing, the NiS... X -CNFs coatings still exhibit good corrosion protection performance.
[0037] (2) Biofouling resistance test Escherichia coli was used as a template organism to evaluate the biofouling resistance of the composite coating. The culture medium used to culture E. coli consisted of 5.0 g / L yeast extract, 10 g / L peptone, and 10 g / L NaCl, with a pH of 7.4. The prepared coating was immersed in the test solution containing the attached organism for 30 days. The coating samples were stained with a fluorescent dye (FilmTracer™ LIVE / DEAD® Biofilm Viability Kit), and the live / dead cell count on the surface was observed using a fluorescence microscope (Leica DM2000, Germany). The antimicrobial efficiency was calculated, as shown in Table 1.
[0038] The pure epoxy coating in Comparative Example 1 had poor antifouling performance, and a large number of E. coli bacteria could be observed adhering to its surface. Figure 3 a). A small amount of E. coli adhered to the surface of the NiS-CNFs coating in Comparative Example 2. The NiS coating in Example 1... X - CNFs coated surfaces show almost no fouling or biological adhesion. Figure 3 c), which shows good anti-fouling performance.
[0039] Table 1. Results of salt spray resistance and biofouling resistance tests of the composite coatings in Examples 1-3 and Comparative Examples 1-2 The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.
Claims
1. A method for preparing modified carbon nanofibers for metal anti-corrosion coatings, characterized in that, Includes the following steps: S1, nickel nitrate hexahydrate and thioacetamide were added to deionized water and stirred until completely dissolved to obtain mixed solution A; carbon nanofibers were added to mixed solution A and ultrasonically dispersed to obtain mixed solution B; mixed solution B was subjected to hydrothermal reaction; cooled to room temperature, washed and dried to obtain nickel sulfide modified carbon nanofibers; S2, the nickel sulfide modified carbon nanofibers are added to an ethanol aqueous solution, ultrasonically dispersed, and then high-purity nitrogen gas is introduced; after irradiation by a xenon lamp, they are filtered, washed, and dried to obtain nickel / nickel sulfide modified carbon nanofibers.
2. The method for preparing modified carbon nanofibers for metal anti-corrosion coatings according to claim 1, characterized in that, The molar ratio of nickel nitrate hexahydrate to thioacetamide is 1:(1-1.05); in the mixed solution A, the concentration of nickel nitrate hexahydrate is 100-150 mmol / L, the concentration of thioacetamide is 105-158 mmol / L; the concentration of carbon nanofiber solution is 100-1000 mg / L; and the mass ratio of nickel nitrate hexahydrate, thioacetamide, and carbon nanofiber is 276:(72-75.6):(6.7-7.3).
3. The method for preparing modified carbon nanofibers for metal anti-corrosion coatings according to claim 1, characterized in that, In step S1, the hydrothermal reaction temperature is 120–180°C, the reaction time is 0.5–6 h, and the cooling method is natural cooling.
4. The method for preparing modified carbon nanofibers for metal anti-corrosion coatings according to claim 1, characterized in that, In step S2, the concentration of the nickel sulfide modified carbon nanofibers in the ethanol aqueous solution is 100-1000 mg / L; the volume ratio of deionized water to ethanol in the ethanol aqueous solution is 1:(0.5-2).
5. The method for preparing modified carbon nanofibers for metal anti-corrosion coatings according to claim 1, characterized in that, In step S2, the power of the xenon lamp light source is 100-500W, and the irradiation time is 1-6h.
6. Nickel / nickel sulfide modified carbon nanofibers obtained by the preparation method of modified carbon nanofibers for metal anti-corrosion coatings according to claims 1 to 5.
7. The method for applying modified carbon nanofibers in metal anti-corrosion coatings according to claim 6, characterized in that, The nickel / nickel sulfide modified carbon nanofibers are added to the metal coating as functional nanofillers, giving the coating both anti-corrosion and anti-fouling functions.
8. The method for applying modified carbon nanofibers in metal anti-corrosion coatings according to claim 7, characterized in that, The process includes the following steps: dispersing the nickel / nickel sulfide modified carbon nanofibers in the matrix resin of the metal coating, stirring thoroughly, mixing evenly with a curing agent, coating onto a metal substrate, and curing to obtain a modified carbon nanofiber reinforced metal anti-corrosion coating.
9. The method for applying modified carbon nanofibers in metal anti-corrosion coatings according to claim 8, characterized in that, The nickel / nickel sulfide modified carbon nanofibers are added to the metal coating at a mass ratio of 0.05% to 1.25%.
10. The method for applying modified carbon nanofibers in metal anti-corrosion coatings according to claim 8, characterized in that, The matrix resin is at least one of epoxy resin, polyurethane, acrylic resin or silicone resin for metal coatings; the curing agent is at least one of polyamide curing agent, polyetheramine curing agent, isocyanate curing agent or acid anhydride curing agent for metal coatings.
11. The application of the modified carbon nanofiber reinforced metal anti-corrosion coating prepared by the application method according to claim 8 in the field of marine metal corrosion protection or fouling control.