Ship wet film rust conversion synchronous anti-corrosion and anti-fouling integrated construction method

Abstract

The invention relates to the technical field of ship corrosion prevention and pollution prevention, and discloses a ship wet film rust conversion synchronous corrosion prevention and pollution prevention integrated construction method which comprises the following steps: performing graded pretreatment on a to-be-constructed surface of a ship, and sequentially completing attachment stripping, rust layer loosening and interface modification; the pretreated surface is coated with the rust-conversion anti-corrosion composite coating in the form of a wet film, and a stable conversion film is formed through chelation reaction of active ingredients in the coating and a rust layer; the gradient construction of the antifouling coating is carried out in the surface drying stage of the conversion film, so that the two coatings form a continuous combination system through molecular permeation. Through rust layer loosening and interface modification, the rust layer does not need to be thoroughly removed, only the rust layer needs to be subjected to loosening treatment and then is modified with a silane coupling agent solution, part of the rust layer can be reserved to serve as a substrate of a rust conversion reaction, the interface polarity can be improved through a silane coupling agent, and the problems that in traditional construction, thorough rust removal operation is large in difficulty and low in efficiency are solved; and meanwhile, the interface bonding force of the rust conversion coating and the base material is improved.

Description

Technical Field

[0001] This invention relates to the field of ship corrosion and antifouling technology, specifically to an integrated construction method for simultaneous wet film rust conversion and corrosion and antifouling on ships. Background Technology

[0002] During long-term service, the underwater and waterline surfaces of ships are prone to rust formation due to seawater erosion, alternating wet and dry conditions, and the attachment of marine organisms. Traditional anti-corrosion construction requires thorough removal of the rust layer until the metal substrate is exposed through sandblasting or mechanical grinding, followed by the application of anti-corrosion primer, intermediate coat, and antifouling topcoat. However, for large ships or complex structural parts, thorough rust removal presents challenges such as limited operating space, long construction periods, and significant dust and noise pollution generated during grinding. Furthermore, traditional anti-corrosion and antifouling coatings are applied in separate layers, with adhesion between layers relying solely on physical bonding. Under ship vibration and water flow impact, interlayer delamination is likely to occur, shortening the lifespan of the anti-corrosion and antifouling coatings. In addition, existing wet film rust-conversion technologies suffer from insufficient interfacial bonding between the rust-conversion coating and the substrate, and the compatibility between the rust-conversion coating surface and the subsequent antifouling layer is poor, easily leading to pinholes or bubbles due to differences in interfacial tension, affecting the overall protective effect. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides an integrated construction method for simultaneous wet film rust removal and anti-corrosion and anti-fouling on ships, solving the problems mentioned in the background section.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a method for integrated construction of wet film rust-transfer and anti-corrosion and anti-fouling on ships, comprising the following steps:

[0005] The ship's surface to be constructed is subjected to graded pretreatment, which sequentially completes the removal of adhering substances, loosening of rust layers, and interface modification.

[0006] The rust-converting and anti-corrosion composite coating is applied to the pretreated surface in wet film form, and a stable conversion film is formed by the chelation reaction between the active ingredients in the coating and the rust layer.

[0007] During the surface drying stage of the conversion membrane, the antifouling coating is applied in a gradient manner, so that the two coatings can form a continuous bonded system through molecular penetration.

[0008] The composite coating is subjected to segmented curing, and non-destructive testing methods are used simultaneously to monitor the coating bonding state and interface integrity.

[0009] Preferably, the hierarchical preprocessing includes:

[0010] The attachment is removed using a high-pressure water jet device. The working pressure of the high-pressure water jet is 15-25MPa, the nozzle moving speed is 0.8-1.2m / s, and the spray angle is 30-45° with the surface.

[0011] Use an angle grinder with a diamond grinding head to loosen the rust layer. The grinding head speed is 2800-3200 r / min, and the grinding path is a cross grid pattern with a grid spacing of 5-8 mm.

[0012] Interface modification was performed using a silane coupling agent solution with a concentration of 3-5 wt%, applied by airless spraying, and the wet film thickness was controlled at 5-8 μm.

[0013] Preferably, the rust-reversing and anti-corrosion composite coating is composed of the following components in the following mass ratio:

[0014] Rust-reducing agent 10-12%, film-forming resin 35-40%, anti-corrosion pigment 15-18%, nano-modifier 2-3%, solvent 25-30%;

[0015] The rust-removing agent is a compound of phosphate ester and tannic acid, with a mass ratio of 2:1.

[0016] The nano-modifier is a silica sol with a particle size of 50-80 nm;

[0017] The anti-corrosion pigment is composed of zinc phosphate, aluminum tripolyphosphate and strontium chrome yellow in a mass ratio of 2:2:1, wherein the particle size of zinc phosphate is 5-10μm and the pH value of aluminum tripolyphosphate is 6-7.

[0018] The solvent is a mixture of xylene, butanol and propylene glycol methyl ether acetate in a volume ratio of 5:3:2.

[0019] Preferably, the wet film coating is applied using a two-component airless spraying device, the mixing ratio of paint component A to curing agent component B is 10:1, the spraying pressure is 0.3-0.5MPa, the distance between the spray gun and the construction surface is maintained at 30-40cm, the wet film thickness is controlled at 100-120μm, and the surface is leveled using a rubber scraper within 30 minutes after coating.

[0020] Preferably, the controlled conditions for the chelation reaction are as follows:

[0021] The ambient temperature is maintained at 15-28℃ and the relative humidity at 50-70%. During the reaction process, the surface temperature is monitored every hour using an infrared thermometer to ensure that the temperature difference with the environment does not exceed 3℃.

[0022] After 2 hours of reaction, the pH value of the exudate on the coating surface was tested with pH test paper. When the pH value stabilized at 6.5-7.5, the reaction was determined to have entered the stable stage.

[0023] The infrared thermometer has a detection wavelength range of 8-14μm, a sampling frequency of 1 time / 30 seconds, and 4 temperature measurement points in each detection area, located at the four corners of the area.

[0024] Preferably, the gradient application of the antifouling coating includes:

[0025] When the conversion film is 40-50% dry, a substrate bonding layer is first coated. The substrate bonding layer is an epoxy resin coating containing aminosilane, and the coating amount is 80-100g / m².

[0026] After an interval of 20-30 minutes, an antifouling functional layer is applied. The antifouling functional layer adopts an acrylic copper-zinc oxide composite system, wherein the copper ion content is 3-5wt%, the zinc oxide is nano-sized particles with a particle size of 20-50nm, and the coating amount is 150-180g / m².

[0027] Preferably, the construction of the substrate bonding layer and the antifouling functional layer adopts the dual-nozzle system of the same spraying equipment. The front nozzle sprays the substrate bonding layer, and the rear nozzle, with a spacing of 5-8cm, simultaneously performs pre-atomization treatment of the antifouling functional layer, so that the two coatings form a 5-10μm mixing transition zone at the interface.

[0028] Preferably, the silane coupling agent solution is prepared by mixing γ-aminopropyltriethoxysilane with deionized water at a volume ratio of 1:20, adding acetic acid accounting for 0.5 wt% of the total solution as a catalyst, stirring at 30-35°C for 30 minutes, and letting it stand for 15 minutes before use.

[0029] The preferred option is...

[0030] The segmented curing process includes:

[0031] The first stage involves natural curing at 23±2℃ for 4-5 hours, with air circulation using a fan and a wind speed controlled at 0.5-0.8m / s.

[0032] The second stage uses far-infrared baking equipment to accelerate curing. The baking temperature is increased from room temperature to 60℃ at a rate of 2℃ / min, and then maintained at this temperature for 2 hours before naturally cooling down to room temperature.

[0033] The non-destructive testing methods include:

[0034] The total thickness of the coating was measured using an ultrasonic thickness gauge. The measurement points were distributed in a quincunx pattern, with 5 measurement points set per square meter, and the deviation was controlled within ±5μm.

[0035] The coating bonding strength was tested using a pull-off adhesion tester at a speed of 10±2 mm / min. At least 3 points were tested in each test area, and the average value was not less than 5 MPa.

[0036] A spark leak detector was used for pinhole detection, with a detection voltage of 3000-5000V and a probe movement speed not exceeding 0.5m / s.

[0037] This invention provides an integrated construction method for simultaneous wet film rust removal and anti-corrosion / antifouling treatment on ships. It has the following beneficial effects:

[0038] 1. This invention, through the steps of rust layer loosening and interface modification in the graded pretreatment, eliminates the need to completely remove the rust layer. It only requires loosening the rust layer and then modifying it with a silane coupling agent solution. This not only retains part of the rust layer as a base for the rust-transforming reaction, but also improves the interfacial polarity through the silane coupling agent. This solves the problems of high difficulty and low efficiency in the traditional construction process of thoroughly removing rust, while also improving the interfacial bonding between the rust-transforming coating and the substrate.

[0039] 2. The chelation reaction between the active ingredients in the rust-converting anti-corrosion composite coating and the loose rust layer can transform the unstable rust layer into a stable conversion film, avoiding the problem of the incompletely removed rust layer continuing to corrode the substrate; and the leveling treatment and segmented curing process during wet film coating reduce the generation of pinholes and bubbles in the coating, improving the density of the anti-corrosion layer.

[0040] 3. The gradient application of the antifouling coating and the mixed transition zone formed by the dual-nozzle system enable the rust-converting anti-corrosion layer and the antifouling layer to achieve chemical and physical bonding through molecular penetration. This solves the problem of insufficient interlayer bonding in traditional layered application, enhances the overall anti-peeling performance of the coating system, and extends the effective period of ship corrosion and antifouling protection. Detailed Implementation

[0041] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0042] Example 1

[0043] A method for integrated wet film rust prevention and antifouling construction on ships, with detailed steps as follows:

[0044] Graded pretreatment: For the rusted areas of the ship deck (rust grade ST3), a high-pressure water jet device (working pressure 20MPa) was used to remove surface marine organisms and floating rust, with a nozzle movement speed of 1.0m / s and a spray angle of 35°; an angle grinder with an 80-mesh diamond grinding head (speed 3000r / min) was used to grind the rust layer in a cross-grit pattern with a grid spacing of 6mm; a 3wt% γ-aminopropyltriethoxysilane solution was prepared (silane and deionized water were mixed at a volume ratio of 1:20, 0.5wt% acetic acid was added, and the mixture was stirred at 32℃ for 30 minutes), and applied using airless spraying, with a wet film thickness of 6μm.

[0045] Rust-converting and anti-corrosion coating application: The rust-converting and anti-corrosion composite coating is prepared according to the following mass ratio: 11% phosphate ester-tannic acid compound rust-converting agent (2:1), 38% epoxy resin, 16% zinc phosphate-aluminum tripolyphosphate-strontium chrome yellow (2:2:1), 2.5% 50nm silica sol, and 28.5% xylene-butanol-propylene glycol methyl ether acetate (5:3:2). A two-component airless spraying equipment is used. Component A and curing agent component B are mixed at a ratio of 10:1. The spraying pressure is 0.4MPa, the spray gun distance from the surface is 35cm, the wet film thickness is 110μm, and the coating is leveled with a rubber scraper after 25 minutes.

[0046] Chelation reaction control: After construction, maintain an ambient temperature of 20℃ and a relative humidity of 60%. Monitor the surface temperature every hour using an 8-14μm infrared thermometer (sampling frequency 1 time / 30 seconds) to ensure that the temperature difference with the environment is ≤3℃. After 2 hours of reaction, the pH value of the exudate is measured to be 7.0, indicating that it has entered the stable stage.

[0047] Gradient application of antifouling coating: When the conversion film is 45% dry, use the front nozzle of the dual-nozzle system to spray the epoxy resin base bonding layer containing aminosilane (coating amount 90g / m²), and the rear nozzle (spacing 6cm) to pre-atomize the acrylic copper-zinc oxide (copper ions 4wt%, 20-50nm zinc oxide) antifouling functional layer. After an interval of 25 minutes, apply the formal coating (coating amount 160g / m²), forming an 8μm mixing transition zone at the interface.

[0048] Segmented curing and testing: Natural curing at 23℃ for 4.5 hours (wind speed 0.6m / s), followed by baking at 60℃ for 2 hours with a temperature increase of 2℃ / min. Simultaneous testing was performed using an ultrasonic thickness gauge (floral pattern, deviation ±5μm), a pull-out tester (speed 10mm / min, strength ≥5MPa), and an electric spark leak detector (4000V, speed 0.4m / s).

[0049] Example 2

[0050] A method for integrated wet film rust prevention and antifouling construction on ships, comprising the following specific steps:

[0051] Graded pretreatment: For the waterline area of ​​the ship (rust grade ST2), the high-pressure water jet pressure is 15MPa, the nozzle moving speed is 0.8m / s, and the angle is 30°; a 60-grit grinding head is used in the angle grinder (speed 2800r / min), and the grinding grid spacing is 5mm; a 4wt% silane solution (prepared as in Example 1) is sprayed to form a wet film with a thickness of 5μm.

[0052] Rust-converting and anti-corrosion coating application: Coating formulation: 10% rust-converting agent, 35% epoxy resin, 15% anti-corrosion pigment, 2% 80nm silica sol, and 38% solvent (proportions as in Example 1). Two-component spraying pressure: 0.3MPa; wet film thickness: 100μm; leveling time: 30 minutes after application.

[0053] Chelation reaction control: ambient temperature 15℃, humidity 50%, infrared thermometry monitoring temperature difference ≤3℃; after 2 hours, pH value 6.5, entering the stable stage.

[0054] Antifouling coating application: When the surface is 40% dry, the coating amount of the substrate bonding layer is 80g / m², the coating amount of the antifouling functional layer (copper ions 3wt%) is 150g / m², the distance between the two nozzles is 5cm, and the transition zone is 5μm.

[0055] Curing and testing: Curing at 21℃ for 5 hours (wind speed 0.5m / s), baking at 60℃ for 2 hours, and testing method is the same as in Example 1.

[0056] Example 3

[0057] A method for integrated wet film rust prevention and antifouling construction on ships, with the following operation procedure:

[0058] Graded pretreatment: corners of ship compartments (rust grade ST3), high-pressure water jet pressure 25MPa, speed 1.2m / s, angle 45°; angle grinder 100-grit head (3200r / min), grid spacing 8mm; 5wt% silane solution sprayed to form a wet film of 8μm.

[0059] Rust-converting and anti-corrosion coating application: Rust-converting agent 12%, epoxy resin 40%, anti-corrosion pigment 18%, 60nm silica sol 3%, solvent 27%. Spraying pressure 0.5MPa, wet film 120μm, leveling in 20 minutes.

[0060] Chelation reaction control: temperature 28℃, humidity 70%, temperature difference ≤3℃; pH value 7.5 after 2 hours.

[0061] Antifouling coating application: When the surface is 50% dry, the base bonding layer is 100g / m², the antifouling functional layer (copper ions 5wt%) is 180g / m², the distance between the two nozzles is 8cm, and the transition zone is 10μm.

[0062] Curing and testing: Curing at 25℃ for 4 hours (wind speed 0.8m / s), baking at 60℃ for 2 hours, and testing standards are the same as above.

[0063] Comparative Example 1

[0064] A traditional method for ship corrosion and pollution prevention construction includes the following steps:

[0065] Surface treatment: The surface of the ship to be treated is thoroughly derusted using sandblasting equipment until the metal substrate is exposed and meets the Sa2.5 standard. The sandblasting pressure is controlled at 0.6-0.8MPa, and 80-120 mesh quartz sand is used. After sandblasting, compressed air is used to remove residual sand particles and dust from the surface.

[0066] Anti-corrosion coating application: Apply epoxy anti-corrosion primer immediately after rust removal using air spraying equipment with a nozzle diameter of 1.5mm and a spraying pressure of 0.3MPa. Control the wet film thickness to 80-100μm. After coating, allow it to cure naturally at 25℃ for 72 hours. Avoid contact with water and contaminants during the curing period.

[0067] Anti-fouling coating application: After the anti-corrosion primer has fully cured, apply the anti-fouling topcoat using the same air spraying equipment. The wet film thickness is 100-120μm. Continue to cure naturally for 48 hours after application, and maintain good ventilation during the curing process.

[0068] Quality inspection: The total thickness of the coating was only measured with a thickness gauge after the anti-fouling topcoat had fully cured to ensure that it met the design requirements. Adhesion and pinhole tests were not performed.

[0069] Comparative Example 2

[0070] A step-by-step construction method for converting wet film to rust on ships, the specific steps of which are as follows:

[0071] Graded pretreatment: High-pressure water jet equipment is used to remove the deposits at a working pressure of 20MPa, a nozzle moving speed of 1.0m / s, and a spray angle of 35°. An angle grinder with an 80-mesh diamond grinding head is used to loosen the rust layer at a grinding head speed of 3000r / min, with a cross-grit pattern and a grid spacing of 6mm. Interface modification is performed using a 3wt% silane coupling agent solution. The solution is prepared by mixing γ-aminopropyltriethoxysilane and deionized water at a volume ratio of 1:20, adding 0.5wt% acetic acid as a catalyst, stirring at 32℃ for 30 minutes, and letting it stand for 15 minutes before use. It is applied by airless spraying, with the wet film thickness controlled at 6μm.

[0072] Rust-converting and anti-corrosion coating application: The rust-converting and anti-corrosion composite coating is composed of the following components in the following mass ratios: 11% rust-converting agent (compound ratio of phosphate ester and tannic acid, mass ratio 2:1), 38% epoxy resin, 16% zinc phosphate-aluminum tripolyphosphate-strontium chrome yellow (mass ratio 2:2:1), 2.5% 50nm silica sol, and 28.5% xylene-butanol-propylene glycol methyl ether acetate (volume ratio 5:3:2). A two-component airless spraying equipment is used. The mixing ratio of coating component A to curing agent component B is 10:1. The spraying pressure is 0.4MPa. The distance between the spray gun and the construction surface is maintained at 35cm. The wet film thickness is controlled at 110μm. The surface is leveled using a rubber scraper within 25 minutes after coating.

[0073] Chelation reaction control: The ambient temperature is maintained at 20℃ and the relative humidity at 60%. During the reaction, the surface temperature is monitored every hour using an infrared thermometer (detection wavelength range 8-14μm, sampling frequency 1 time / 30 seconds, 4 temperature measurement points are set in each detection area, located at the four corners of the area) to ensure that the temperature difference with the environment does not exceed 3℃. After 2 hours of reaction, the pH value of the exudate on the coating surface is detected using pH test paper. When the pH value stabilizes at 7.0, the reaction is considered to have entered the stable stage.

[0074] Complete curing of the rust-converting layer: After the rust-converting coating has fully cured for 7 days (during which the ambient temperature is maintained at 23±2℃ and the relative humidity at 50-70%), the anti-fouling coating should be applied.

[0075] Antifouling coating application: A single-nozzle spraying device is used. First, a base bonding layer is applied, which is an epoxy resin coating containing aminosilane, with a coating amount of 90g / m². After it is completely surface dry (after an interval of 24 hours), the antifouling functional layer is applied. The antifouling functional layer adopts an acrylic copper-zinc oxide composite system, in which the copper ion content is 4wt% and the zinc oxide is nano-sized particles with a particle size of 20-50nm, with a coating amount of 160g / m². There is no pre-atomization treatment or mixing transition zone.

[0076] Segmented Curing and Testing: The first stage involves natural curing at 23℃ for 4.5 hours, with air circulation using a fan and a wind speed controlled at 0.6m / s. The second stage uses far-infrared baking equipment for accelerated curing, with the baking temperature increasing from room temperature to 60℃ at a rate of 2℃ / min, maintained at this temperature for 2 hours, and then naturally cooled to room temperature. An ultrasonic thickness gauge is used to detect the total coating thickness, with test points distributed in a quincunx pattern, 5 test points per square meter, and the deviation controlled within ±5μm. A pull-off adhesion tester is used to test the coating bonding strength at a test speed of 10mm / min, with at least 3 points tested in each test area, and the average value not less than 5MPa. A spark leak detector is used for pinhole detection, with a test voltage of 4000V and a probe movement speed not exceeding 0.4m / s.

[0077] Comparative Example 3

[0078] A method for applying a single-component rust-converting coating to ships, comprising the following specific steps:

[0079] Graded pretreatment: High-pressure water jet equipment is used to remove the deposits. The working pressure of the high-pressure water jet is 20MPa, the nozzle moving speed is 1.0m / s, and the spray angle is 35° to the surface. The rust layer is loosened using an angle grinder with an 80-mesh diamond grinding head. The grinding head speed is 3000r / min, and the grinding trajectory is a cross-grit pattern with a grid spacing of 6mm. Interface modification is performed using a 3wt% silane coupling agent solution. The solution is made by mixing γ-aminopropyltriethoxysilane and deionized water at a volume ratio of 1:20, adding 0.5wt% acetic acid as a catalyst, stirring at 32℃ for 30 minutes, and letting it stand for 15 minutes before use. It is applied by airless spraying, and the wet film thickness is controlled at 6μm.

[0080] Rust-converting anti-corrosion coating application: The rust-converting anti-corrosion coating is composed of the following components in the following mass ratios: 11% rust-converting agent (the rust-converting agent is a compound of phosphate ester and tannic acid, with a mass ratio of 2:1), 38% film-forming resin, 16% anti-corrosion pigment (the anti-corrosion pigment is a compound of zinc phosphate, aluminum tripolyphosphate, and strontium chrome yellow in a mass ratio of 2:2:1, where the particle size of zinc phosphate is 5-10μm, and the pH value of aluminum tripolyphosphate is 6-7), and 28.5% solvent (the solvent is a mixture of xylene, butanol, and propylene glycol methyl ether acetate, with a volume ratio of 5:3:2). It does not contain nano-modifiers. A two-component airless spraying equipment is used. The mixing ratio of coating component A to curing agent component B is 10:1. The spraying pressure is 0.4MPa, the distance between the spray gun and the construction surface is maintained at 35cm, and the wet film thickness is controlled at 110μm. No rubber scraper leveling treatment is performed after coating.

[0081] Chelation reaction control: The ambient temperature is maintained at 20℃ and the relative humidity at 60%. During the reaction, the surface temperature is monitored every hour using an infrared thermometer (detection wavelength range 8-14μm, sampling frequency 1 time / 30 seconds, 4 temperature measurement points are set in each detection area, located at the four corners of the area) to ensure that the temperature difference with the environment does not exceed 3℃. After 2 hours of reaction, the pH value of the exudate on the coating surface is detected using pH test paper. When the pH value stabilizes at 7.0, the reaction is considered to have entered the stable stage.

[0082] Antifouling coating application: A single-nozzle spraying device is used. First, a base bonding layer is applied, which is an epoxy resin coating containing aminosilane, with a coating amount of 90g / m². After a 30-minute interval, the antifouling functional layer is applied. The antifouling functional layer adopts an acrylic copper-zinc oxide composite system, in which the copper ion content is 4wt% and the zinc oxide is nano-sized particles with a particle size of 20-50nm, with a coating amount of 160g / m², and no mixing transition zone.

[0083] Segmented Curing and Testing: The first stage involves natural curing at 23℃ for 4.5 hours, with air circulation using a fan and a wind speed controlled at 0.6m / s. The second stage uses far-infrared baking equipment for accelerated curing, with the baking temperature increasing from room temperature to 60℃ at a rate of 2℃ / min, maintained at this temperature for 2 hours, and then naturally cooled to room temperature. An ultrasonic thickness gauge is used to detect the total coating thickness, with test points distributed in a quincunx pattern, 5 test points per square meter, and the deviation controlled within ±5μm. A pull-off adhesion tester is used to test the coating bonding strength at a test speed of 10mm / min, with at least 3 points tested in each test area, and the average value not less than 5MPa. A spark leak detector is used for pinhole detection, with a test voltage of 4000V and a probe movement speed not exceeding 0.4m / s.

[0084] Experimental Example 1

[0085] Performance tests were conducted on Examples 1-3 and Comparative Examples 1-3:

[0086] Experimental design: Six identical ship steel plates (1m×1m) were selected to simulate a marine environment (immersion in 3.5% NaCl solution + ultraviolet aging cycle), with three replicates per group.

[0087] Test metrics:

[0088] Adhesion: According to GB / T5210-2006, the adhesion of the coating system was tested by the pull-off method. Three points were measured on each board and the average value was taken.

[0089] Salt spray resistance: According to GB / T1771-2007, a neutral salt spray test of 5000 hours is conducted to evaluate the percentage of rusted area.

[0090] Antifouling performance: Immersed in artificial seawater (containing marine bacteria) for 365 days, the amount of biofouling on the surface was measured.

[0091] Test results:

[0092] project Adhesion (MPa) Salt spray corrosion rate (%) Bioattachment amount (g / m²) Example 1 6.2 3.5 12 Example 2 5.8 4.2 15 Example 3 6.5 3.1 10 Comparative Example 1 4.5 8.7 28 Comparative Example 2 5.0 6.3 22 Comparative Example 3 4.8 7.5 25

[0093] Results analysis:

[0094] The adhesion of Examples 1-3 was significantly higher than that of the Comparative Examples, as the transition zone formed by gradient construction enhanced interlayer bonding; the salt spray corrosion rate was low, thanks to the rust-converting layer transforming the rust layer into a stable protective structure, and the nano-modifier improving the coating density; the antifouling performance was excellent, attributed to the dual-nozzle technology which ensured uniform distribution and slow-release stability of the antifouling agent. Comparative Example 1, lacking rust-converting treatment and with independent interlayer layers, exhibited poor adhesion and corrosion resistance; Comparative Example 2, lacking a transition zone due to step-by-step construction, suffered from insufficient interlayer bonding; Comparative Example 3, lacking nano-modification and transition technology, showed reduced coating integrity and antifouling durability.

[0095] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for integrated construction of wet film rust prevention and anti-fouling on ships, characterized in that, Includes the following steps: The ship's surface to be constructed is subjected to graded pretreatment, which sequentially completes the removal of adhering substances, loosening of rust layers, and interface modification. The rust-converting and anti-corrosion composite coating is applied to the pretreated surface in wet film form, and a stable conversion film is formed by the chelation reaction between the active ingredients in the coating and the rust layer. During the surface drying stage of the conversion membrane, the antifouling coating is applied in a gradient manner, so that the two coatings can form a continuous bonded system through molecular penetration. The composite coating is subjected to segmented curing, and non-destructive testing methods are used simultaneously to monitor the coating bonding state and interface integrity.

2. The integrated construction method for simultaneous wet film rust removal and anti-corrosion / anti-fouling on ships according to claim 1, characterized in that, The hierarchical preprocessing includes: The attachment is removed using a high-pressure water jet device. The working pressure of the high-pressure water jet is 15-25MPa, the nozzle moving speed is 0.8-1.2m / s, and the spray angle is 30-45° with the surface. Use an angle grinder with a diamond grinding head to loosen the rust layer. The grinding head speed is 2800-3200 r / min, and the grinding path is a cross grid pattern with a grid spacing of 5-8 mm. Interface modification was performed using a silane coupling agent solution with a concentration of 3-5 wt%, applied by airless spraying, and the wet film thickness was controlled at 5-8 μm.

3. The integrated construction method for simultaneous wet film rust removal and anti-corrosion / anti-fouling on ships according to claim 1, characterized in that, The rust-reducing and anti-corrosion composite coating is composed of the following components in the following mass ratio: Rust-reducing agent 10-12%, film-forming resin 35-40%, anti-corrosion pigment 15-18%, nano-modifier 2-3%, solvent 25-30%; The rust-removing agent is a compound of phosphate ester and tannic acid, with a mass ratio of 2:

1. The nano-modifier is a silica sol with a particle size of 50-80 nm; The anti-corrosion pigment is composed of zinc phosphate, aluminum tripolyphosphate and strontium chrome yellow in a mass ratio of 2:2:1, wherein the particle size of zinc phosphate is 5-10μm and the pH value of aluminum tripolyphosphate is 6-7. The solvent is a mixture of xylene, butanol and propylene glycol methyl ether acetate in a volume ratio of 5:3:

2.

4. The integrated construction method for simultaneous wet film rust conversion and anti-corrosion and anti-fouling of ships according to claim 1, characterized in that, The wet film coating is applied using a two-component airless spraying device. The mixing ratio of paint component A to curing agent component B is 10:

1. The spraying pressure is 0.3-0.5MPa. The distance between the spray gun and the construction surface is maintained at 30-40cm. The wet film thickness is controlled at 100-120μm. The surface is leveled using a rubber scraper within 30 minutes after coating.

5. The integrated construction method for simultaneous wet film rust removal and anti-corrosion / anti-fouling on ships according to claim 1, characterized in that, The control conditions for the chelation reaction are as follows: The ambient temperature is maintained at 15-28℃ and the relative humidity at 50-70%. During the reaction process, the surface temperature is monitored every hour using an infrared thermometer to ensure that the temperature difference with the environment does not exceed 3℃. After 2 hours of reaction, the pH value of the exudate on the coating surface was tested with pH test paper. When the pH value stabilized at 6.5-7.5, the reaction was determined to have entered the stable stage. The infrared thermometer has a detection wavelength range of 8-14μm, a sampling frequency of 1 time / 30 seconds, and 4 temperature measurement points in each detection area, located at the four corners of the area.

6. The integrated construction method for simultaneous wet film rust conversion and anti-corrosion and anti-fouling on ships according to claim 1, characterized in that, The gradient application of the antifouling coating includes: When the conversion film is 40-50% dry, a substrate bonding layer is first coated. The substrate bonding layer is an epoxy resin coating containing aminosilane, and the coating amount is 80-100g / m². After an interval of 20-30 minutes, an antifouling functional layer is applied. The antifouling functional layer adopts an acrylic copper-zinc oxide composite system, wherein the copper ion content is 3-5wt%, the zinc oxide is nano-sized particles with a particle size of 20-50nm, and the coating amount is 150-180g / m².

7. The integrated construction method for simultaneous wet film rust conversion and anti-corrosion and anti-fouling on ships according to claim 6, characterized in that, The construction of the base bonding layer and the antifouling functional layer adopts the dual-nozzle system of the same spraying equipment. The front nozzle sprays the base bonding layer, and the rear nozzle, with a spacing of 5-8cm, simultaneously performs pre-atomization treatment of the antifouling functional layer, so that the two coatings form a 5-10μm mixing transition zone at the interface.

8. The integrated construction method for simultaneous wet film rust removal and anti-corrosion / anti-fouling on ships according to claim 2, characterized in that, The silane coupling agent solution is prepared by mixing γ-aminopropyltriethoxysilane with deionized water at a volume ratio of 1:20, adding acetic acid accounting for 0.5 wt% of the total solution as a catalyst, stirring at 30-35℃ for 30 minutes, and letting it stand for 15 minutes before use.

9. The integrated construction method for simultaneous wet film rust removal and anti-corrosion / anti-fouling on ships according to claim 1, characterized in that, The segmented curing process includes: The first stage involves natural curing at 23±2℃ for 4-5 hours, with air circulation using a fan and a wind speed controlled at 0.5-0.8m / s. The second stage uses far-infrared baking equipment to accelerate curing. The baking temperature is increased from room temperature to 60℃ at a rate of 2℃ / min, and then maintained at this temperature for 2 hours before naturally cooling down to room temperature.

10. The integrated construction method for simultaneous wet film rust removal and anti-corrosion / anti-fouling on ships according to claim 1, characterized in that, The non-destructive testing methods include: The total thickness of the coating was measured using an ultrasonic thickness gauge. The measurement points were distributed in a quincunx pattern, with 5 measurement points set per square meter, and the deviation was controlled within ±5μm. The coating bonding strength was tested using a pull-off adhesion tester at a speed of 10±2 mm / min. At least 3 points were tested in each test area, and the average value was not less than 5 MPa. A spark leak detector was used for pinhole detection, with a detection voltage of 3000-5000V and a probe movement speed not exceeding 0.5m / s.