A coating material for electrical control devices in offshore wind power plants and a production process

Abstract

This application relates to the field of specialty coatings technology, specifically disclosing a coating material and its preparation process for electrical control devices in coastal wind power equipment. The coating material for electrical control devices in coastal wind power equipment is a three-layer composite structure sequentially constructed on the surface of a circuit board substrate. The coating material includes a conversion layer coating adhered to the substrate surface, a cold-sprayed zinc coating applied over the conversion layer, and a single-component nano-composite silicone resin coating applied to the surface of the cold-sprayed zinc coating. The conversion layer coating includes a phosphate-containing epoxy resin-based coating, and the total dry film thickness of the coating is 28 to 56 micrometers. The coating material of this application has the advantage of excellent structural synergistic protective performance.

Description

Technical Field

[0001] This application relates to the field of specialty coatings technology, and more specifically, to a coating material and preparation process for electrical control devices in coastal wind power equipment. Background Technology

[0002] With the rapid development of offshore and coastal wind power, wind power generation equipment is constantly exposed to the extreme marine atmospheric environment characterized by high salt spray, high humidity, high wind speed, and strong ultraviolet radiation. As the core control unit of the wind turbine, the reliability and lifespan of the electronic control device directly affect the overall operational safety and power generation efficiency. However, traditional protective coatings are prone to aging and peeling under the alternating effects of multiple corrosive media, leading to moisture absorption, dust accumulation, and corrosion on circuit boards. This results in frequent failures and downtime for maintenance, significantly increasing the total lifecycle operation and maintenance costs of wind power projects.

[0003] Currently, the protection of circuit boards for wind turbine equipment mostly adopts single-function coatings or conventional heavy-duty anti-corrosion systems, which have the following prominent problems: First, the coating system has insufficient weather resistance and it is difficult to maintain adhesion and density in high-salt and high-humidity environments for a long time; second, most high-performance coatings require high-temperature curing, which can easily cause thermal damage to precision electronic components during construction; third, traditional coatings have single functions and lack integrated performance of dustproof, hydrophobic, insulating and anti-corrosion; fourth, maintenance and repair are difficult, especially in complex structures such as welds and connectors, which are prone to corrosion hazards, and the repair process is complicated and the window period is short.

[0004] To overcome the above-mentioned defects, it is urgent to develop a composite coating material that can be applied at room temperature and form a coating with excellent adhesion, high hardness, superhydrophobicity, salt spray resistance, high temperature resistance and good insulation properties, so as to achieve long-term maintenance-free and reliable operation of circuit boards in harsh marine environments. Summary of the Invention

[0005] To address the aforementioned issues, this application provides a coating material and its preparation process for electrical control devices in coastal wind power equipment.

[0006] The first part of this application provides a coating material for electrical control devices in coastal wind power equipment, which adopts the following technical solution: A coating material for electrical control devices in coastal wind power equipment, the coating material being a three-layer composite structure sequentially constructed on the surface of a circuit board substrate, the coating material comprising a conversion layer coating adhered to the substrate surface, a cold-sprayed zinc layer coating coated on the conversion layer, and a single-component nano-composite silicone resin coating coated on the surface of the cold-sprayed zinc layer, the conversion layer coating comprising a phosphate-containing epoxy resin-based coating, and the total dry film thickness of the coating material being 28 to 56 micrometers.

[0007] By employing the above technical solution, the conversion layer acts directly on the substrate interface, achieving corrosion stabilization and basic adhesion; the middle cold-sprayed zinc layer provides active electrochemical protection (cathode protection) and dense physical shielding; the outermost silicone nano-coating undertakes the functions of resisting environmental erosion and imparting superhydrophobicity and high insulation to the surface. Limiting the total dry film thickness to 28 to 56 micrometers ensures that sufficient protection is provided while avoiding increased stress, decreased flexibility, and potential interference with the electrical performance of the circuit board caused by excessive coating thickness, thus achieving a balance between protective effectiveness and applicability.

[0008] Optionally, the components of the conversion coating, by mass percentage, include 35%-50% epoxy resin, 5%-15% phosphate, 0.5%-2% a compound of benzotriazole and γ-glycidyl etheroxypropyltrimethoxysilane, 1%-3% nano silica, 0.2%-0.8% polyether-modified organosilicon, and the balance being propylene glycol methyl ether acetate.

[0009] By employing the above technical solutions, epoxy resin, as the film-forming matrix, provides excellent adhesion and mechanical strength for the coating. Phosphate, as the core corrosion conversion agent, transforms the existing trace iron oxides on the substrate surface into a stable and dense phosphate passivation film, fundamentally preventing rust propagation. The compound of benzotriazole and silane coupling agent exerts a synergistic corrosion inhibition and coupling effect, both inhibiting corrosion of the metal substrate and enhancing the coating's cohesion and interfacial bonding. The introduction of nano-silica enhances toughness, improving the coating's wear resistance and impact resistance. Polyether-modified organosilicon, as a wetting and dispersing agent, ensures the uniform dispersion of all components, especially nanoparticles and pigments, thereby guaranteeing the uniformity and stability of the coating quality. Propylene glycol methyl ether acetate, as a solvent, provides suitable application viscosity and volatility gradient.

[0010] Optionally, the phosphate includes at least one of zinc phosphate, ferric phosphate, or manganese phosphate.

[0011] By adopting the above technical solutions, zinc phosphate has wide applications and produces a high-density conversion film; iron phosphate can form an amorphous protective layer with excellent adhesion; and manganese phosphate can improve the hardness and weather resistance of the conversion film. Limiting the application to these specific substances ensures the effectiveness and reliability of the core reaction of the conversion layer, thereby guaranteeing the stable realization of the underlying protective function and avoiding the risk of protective failure caused by using other phosphates with unclear effects or unstable conversion products.

[0012] Optionally, the components of the cold-sprayed zinc coating, by mass percentage, include 80%-90% zinc powder, 8%-15% mixed resin, 0.5%-1.5% fumed silica, 0.3%-1% zinc fatty acid, and the balance being a mixture of xylene and n-butanol. The mixed resin is a compound of acrylic resin and epoxy resin in a mass ratio of (2.5-3.5):1.

[0013] By employing the above technical solution, the zinc powder content reaches 80%-90%, ensuring a sufficiently high zinc content in the coating to form a continuous and effective sacrificial anode protection network. When the coating is damaged, it preferentially corrodes zinc while protecting the steel substrate. A mixture of acrylic resin and epoxy resin at a ratio of (2.5-3.5:1) is used as the mixed resin, combining the advantages of acrylic resin's fast drying and good flexibility with epoxy resin's strong adhesion and excellent chemical resistance. This allows the coating to achieve excellent mechanical properties and durability while being applied quickly. Fumed silica, as a thixotropic agent, prevents the sedimentation of high-density zinc powder during storage and application, ensuring coating uniformity. Zinc fatty acid, as a stabilizer, effectively delays the oxidation of zinc powder in the coating, extending the coating's open-can lifespan and enhancing the protective efficacy of active zinc.

[0014] Optionally, the zinc powder has a particle size D50 of 3 to 15 micrometers.

[0015] By adopting the above technical solution, firstly, the relatively fine zinc powder particles can be more densely packed, forming a coating with lower porosity and a denser structure, thus enhancing the physical shielding effect of the coating and preventing the penetration of corrosive media. Secondly, the fine zinc powder has a larger specific surface area, which can provide a more sufficient and uniform anodic protection current during electrochemical corrosion, improving the efficiency and response speed of cathodic protection. Finally, the suitable particle size distribution is beneficial to the spraying application of the coating, resulting in a smoother and more uniform coating appearance.

[0016] Optionally, the preparation method of the single-component nanocomposite silicone resin coating includes the following steps: Nano-silica was dispersed in a solvent, and a silane coupling agent was added to carry out a surface grafting reaction to obtain a modified nanoparticle dispersion. Under an inert atmosphere, at least one alkoxysilane monomer undergoes a hydrolysis-condensation reaction to form an organosilicon prepolymer. The modified nanoparticle dispersion was uniformly mixed with the organosilicon prepolymer under shear force, and then a curing catalyst and additives were added. After degassing treatment, the single-component nanocomposite silicone resin coating was obtained.

[0017] By employing the above technical solution, firstly, surface grafting modification of nano-silica is performed using a silane coupling agent, introducing active groups capable of chemically bonding with organosilicon resins onto its surface. This fundamentally solves the problem of easy agglomeration of nanoparticles, ensuring their uniform nanoscale dispersion within the resin. Secondly, organosilicon prepolymers are prepared through the hydrolysis and condensation of alkoxysilane monomers, allowing for flexible control of the resin's molecular structure and properties. Finally, the modified nanoparticles and prepolymers are composited under shear force, immobilizing the nanoparticles as reinforcing points within the organosilicon crosslinking network. The coating prepared by this method ultimately imparts extremely high surface hardness, excellent wear resistance, durable superhydrophobicity, and good thermal stability to the coating simultaneously. Furthermore, as a single-component system, it is convenient for storage and application.

[0018] Optionally, the dry film thickness of the conversion layer coating is 3 to 8 micrometers, the dry film thickness of the cold spray zinc coating is 15 to 30 micrometers, and the dry film thickness of the single-component nanocomposite silicone resin coating is 10 to 18 micrometers.

[0019] By employing the above technical solutions, the conversion layer thickness is 3-8 micrometers, sufficient to achieve effective corrosion conversion and form a continuous and dense underlayer, while avoiding excessive thickness that could increase brittleness or affect the bonding of the upper layer. The cold-sprayed zinc layer thickness is 15-30 micrometers, within which sufficient zinc can be provided for long-term cathodic protection, while also forming an effective physical barrier layer, and the internal stress of the coating is controllable, making it less prone to cracking. The single-component organosilicon-modified nano-surface layer thickness is 10-18 micrometers, sufficient to construct a complete and dense functional surface, ensuring the full realization of superhydrophobicity, high insulation, and weather resistance properties, while maintaining good flexibility and light transmittance of the coating.

[0020] Secondly, this application provides a process for preparing a coating material for an electrical control device in coastal wind power equipment.

[0021] A process for preparing a coating material for electrical control devices in coastal wind power equipment includes the following steps: The surface of the circuit board substrate is cleaned and roughened. The surface cleanliness of the substrate after treatment reaches Sa 2.5 level, and the surface roughness Ra is 20 to 50 micrometers. The surface of the substrate after treatment is then subjected to low-temperature plasma treatment for 30-120 seconds. A conversion layer coating is applied to the activated substrate surface. After the conversion layer coating is surface dry, a cold spray zinc coating is applied. After the cold spray zinc coating is surface dry, a single-component nano-composite silicone resin coating is applied. A staged curing process is adopted, curing at 20-30℃ for 4-8 hours, then curing at 40-60℃ for 2-4 hours, and then continuing to cure at 20-30℃ for a total time of not less than 24 hours.

[0022] By adopting the above technical solution, firstly, the cleaning and roughening combined with low-temperature plasma treatment not only removes physical contaminants but also introduces a large number of polar functional groups into the substrate surface through plasma activation, greatly increasing the surface energy and providing an ideal chemical bonding interface for the conversion layer coating. This is a key prerequisite for obtaining ultra-high adhesion. Secondly, the clearly defined process of sequentially coating and allowing the "conversion layer - cold spray zinc layer - nano-surface layer" ensures good wetting and bonding between each layer, avoiding interlayer delamination. Finally, low-temperature initial curing allows the coating to fully level and initially cross-link; the medium-temperature strengthening stage accelerates the deep curing reaction, improving the final hardness and chemical resistance of the coating; and returning to low-temperature final curing helps release internal stress, making the coating system more stable. This process ensures the ultimate performance of the coating while avoiding thermal damage to circuit board components throughout the entire process.

[0023] In summary, this application has the following beneficial effects: 1. Because this application adopts a three-layer composite structure design, it provides multiple protection mechanisms of chemical conversion, electrochemical cathodic protection and physical barrier barrier. Each layer has a clear function and synergistic effect, thus providing systematic and long-term protection for the circuit board. While ensuring excellent anti-corrosion, dustproof and insulation performance, the overall coating thickness is moderate, avoiding problems such as stress and flexibility caused by excessive thickness.

[0024] 2. The preferred material components and formulations in this application significantly improve the adhesion, density, weather resistance and functionality of the coating.

[0025] 3. The preparation method of this application, by introducing low-temperature plasma treatment of the substrate surface, interlayer construction control and segmented temperature rise curing system, not only greatly optimizes the bonding force between the coating and the substrate and between each layer, but also ensures the full formation of coating performance and effective release of internal stress. The whole process can be completed at room temperature or medium and low temperature, avoiding damage to circuit board components by high temperature, and has the advantages of reliability, operability and process friendliness. Detailed Implementation

[0026] The following detailed description of this application is provided in conjunction with the embodiments. It should be noted that: unless otherwise specified, the conditions in the following embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following embodiments are all from commercially available sources.

[0027] Preparation Example 1 A method for preparing a single-component nanocomposite silicone resin coating: The raw materials used in this preparation example are as follows: 5 g of nano-sized silica with a particle size of 10–20 nm; 150 mL of anhydrous ethanol; KH-570 silane coupling agent 2 g; The alkoxysilane monomers selected are 30g of methyltrimethoxysilane (MTMS) and 10g of phenyltrimethoxysilane (PTMS); The curing catalyst used was 0.5 g of dibutyltin dilaurate (DBTL); The additives selected are 0.3 g of polyether-modified siloxane, 0.2 g of polysiloxane, deionized water, and dilute hydrochloric acid (pH ≈ 4).

[0028] The preparation steps used in this preparation example are as follows: 5 g of nano-silica was dispersed in 100 mL of anhydrous ethanol and ultrasonically treated for 30 min to obtain a uniform nano-silica dispersion. The dispersion was transferred to a four-necked flask, and a stirrer, condenser, and nitrogen inlet were installed. Nitrogen protection was activated. The temperature was raised to 65 °C, and 2 g of silane coupling agent KH-570 (dissolved in 20 mL of anhydrous ethanol) was slowly added dropwise. Under nitrogen protection, the reaction was carried out at 65 °C for 3 h to obtain a surface-grafted modified nano-silica dispersion. After the reaction was completed, the dispersion was cooled to room temperature and sealed for later use.

[0029] In another four-necked flask, 30 g of methyltrimethoxysilane (MTMS) and 10 g of phenyltrimethoxysilane (PTMS) were added, and nitrogen gas was purged to remove air. The flask was placed in an ice-water bath, and a hydrolysate prepared from deionized water and dilute hydrochloric acid was slowly added dropwise, maintaining a total molar ratio of water to alkoxy groups of 1.2:1. The dropping rate was controlled, and the system temperature was kept ≤20°C. After the addition was complete, the ice bath was removed, the temperature was raised to 60°C, and the reaction was stirred for 4 h to obtain a transparent, viscous organosilicon prepolymer solution.

[0030] The modified nano-silica dispersion was slowly added to the organosilicon prepolymer solution while stirring at 3000 rpm in a high-speed shear disperser. Shear mixing was continued for 30 min to ensure uniform dispersion of nanoparticles in the prepolymer. Then, 0.5 g of curing catalyst DBTL, 0.3 g of leveling agent, and 0.2 g of defoamer were added, and shearing was continued at 2000 rpm for 10 min. The mixture was then transferred to a vacuum degassing apparatus and degassed at −0.095 MPa and room temperature for 15 min until no visible bubbles remained.

[0031] Example 1 A preparation process for a coating material used in the electrical control device of coastal wind power equipment: In this embodiment, the substrate is a copper-clad epoxy resin-based circuit board (FR-4) with dimensions of 150 mm × 100 mm × 1.6 mm.

[0032] In this embodiment, the target dry film thickness of the conversion layer coating is 6 μm. The formulation is as follows, based on a total preparation of 100 g: Epoxy resin (E-44) 43.0 g, zinc phosphate 5.0 g, iron phosphate 5.0 g, benzotriazole 0.65 g, KH-560 silane coupling agent 0.65 g, nano silica (20±10nm) 2.0 g, polyether modified silicone leveling agent (BYK-333) 0.5 g, propylene glycol methyl ether acetate (PMA) 43.2 g.

[0033] Dissolve the epoxy resin in a portion of the PMA solvent and stir at medium speed until completely dissolved. Add zinc phosphate, ferric phosphate, and nano-silica, and disperse at 1200 rpm for 20 minutes. Premix benzotriazole with KH-560 and add it to the system. Add leveling agent, adjust the viscosity with the remaining solvent, stir at medium speed for 10 minutes, and filter through a 200-mesh filter.

[0034] In this embodiment, the target dry film thickness of the cold-sprayed zinc coating is 22 μm, and the formulation is as follows: Zinc powder (D50=9±1μm) 85.0 g, acrylic resin solution (50% solid content) 17.26 g (providing 8.63 g of dry resin), epoxy resin solution (E-20, 60% solid content) 4.78 g (providing 2.87 g of dry resin), fumed silica (R972) 1.0 g, zinc stearate 0.65 g, xylene 1.3 g, n-butanol 0.55 g Mix the acrylic resin solution, epoxy resin solution, xylene, and n-butanol thoroughly. Add zinc stearate and fumed silica while stirring, and disperse for 10 minutes. Slowly add zinc powder, avoiding dust generation. After adding all zinc powder, increase the stirring speed to 800-1000 rpm and continue dispersing for 30 minutes until uniform and free of lumps. Stir continuously at 120 rpm before use to prevent sedimentation.

[0035] In this embodiment, the target dry film thickness of the single-component organosilicon-modified nanocoating is 14 μm, and it is prepared by the method of Preparation Example 1.

[0036] The coating preparation process in this embodiment is as follows: The circuit board substrate surface was sandblasted with 180-mesh quartz sand to remove the oxide layer and contaminants. After treatment, the substrate surface cleanliness reached Sa 2.5 level, and the surface roughness Ra was 35 μm. Airborne dust was blown away with clean compressed air, followed by ultrasonic cleaning with isopropanol for 5 minutes, and then drying.

[0037] The clean and dry substrate was placed in a low-temperature plasma treatment instrument, and argon gas was introduced at a flow rate of 20 L / min. The treatment was carried out for 75 seconds at a power of 300 W.

[0038] The prepared conversion coating was uniformly sprayed onto the activated substrate surface using an air spraying method. The wet film thickness was controlled to achieve a dry film thickness of 6 μm. Surface drying took approximately 30 minutes at 25°C and relative humidity ≤60%.

[0039] Stir the cold-sprayed zinc coating thoroughly until it is uniform and free of sedimentation, then spray it onto the surface-dried conversion layer. Control the number of spray coats and film thickness to achieve a dry film thickness of 22 μm. Surface dry for approximately 1 hour at 25°C and relative humidity ≤60%.

[0040] A single-component nanocomposite silicone resin coating was uniformly applied to the surface of the cold-sprayed zinc layer after it had dried. The coating amount was controlled to achieve a dry film thickness of 14 μm.

[0041] First, cure at 25°C in a well-ventilated environment for 6 hours. Then, raise the temperature to 50°C and cure for 3 hours. Next, lower the temperature to 25°C and continue curing for 15 hours. After curing, allow the coating to age at room temperature for 7 days.

[0042] Example 2 A preparation process for a coating material used in the electrical control device of coastal wind power equipment: The difference from Example 1 is that when preparing the conversion layer coating, 35 grams of epoxy resin, 5 grams of phosphate, 0.5 grams of a compound of benzotriazole and γ-glycidyl etheroxypropyltrimethoxysilane, 1 gram of nano-silica, and 0.2 grams of polyether-modified organosilicon are weighed out. Then, 58.3 grams of propylene glycol methyl ether acetate solvent are added to bring the total weight of the coating to 100 grams. All other steps are the same.

[0043] Example 3 A preparation process for a coating material for electrical control devices in coastal wind power equipment: The difference from Example 1 is that 50g of epoxy resin, 15g of phosphate, 2g of a compound of benzotriazole and γ-glycidyl etheroxypropyltrimethoxysilane, 3g of nano-silica, and 0.8g of polyether-modified organosilicon are weighed out, followed by the addition of 29.2g of propylene glycol methyl ether acetate solvent to bring the total mass to 100g. All other steps are the same.

[0044] Example 4 A preparation process for a coating material for electrical control devices in coastal wind power equipment: The difference from Example 1 is that only 10g of zinc phosphate is used as phosphate.

[0045] Example 5 A preparation process for a coating material for electrical control devices in coastal wind power equipment: The difference from Example 1 is that the phosphate used is 5.0 g of manganese phosphate and 5.0 g of iron phosphate.

[0046] Example 6 A preparation process for a coating material used in the electrical control device of coastal wind power equipment: The difference from Example 1 is that in the preparation of the cold-sprayed zinc coating, acrylic resin and epoxy resin are mixed in a mass ratio of 2.5:1, totaling 15g as the mixed resin component. Subsequently, 80g of zinc powder, 1.5g of fumed silica, and 1g of zinc fatty acid are weighed. All the above solids and resin components are mixed with a mixed solvent of xylene and n-butanol to bring the total mass of the coating to 100g.

[0047] Example 7 A preparation process for a coating material used in the electrical control device of coastal wind power equipment: The difference from Example 1 is that in the preparation of the cold-sprayed zinc coating, acrylic resin and epoxy resin are mixed in a mass ratio of 3.5:1, totaling 8g as the mixed resin component. Subsequently, 90g of zinc powder, 0.5g of fumed silica, and 0.3g of zinc fatty acid are weighed. All the above solids and resin components are mixed with a mixed solvent of xylene and n-butanol to make the total mass of the coating reach 100g.

[0048] Example 8 A preparation process for a coating material for electrical control devices in coastal wind power equipment: The difference from Example 1 is that the particle size D50 of the zinc powder is 3 to 5 micrometers.

[0049] Example 9 A preparation process for a coating material for electrical control devices in coastal wind power equipment: The difference from Example 1 is that the particle size D50 of the zinc powder is 13 to 15 micrometers.

[0050] Example 10 A preparation process for a coating material for electrical control devices in coastal wind power equipment: The difference from Example 1 is that the single-component nanocomposite silicone resin coating used is YM-482 single-component organosilicon topcoat from Guangdong Hongfang Coatings Technology Co., Ltd.

[0051] Example 11 A preparation process for a coating material for an electrical control device in coastal wind power equipment: The difference from Example 1 is that the dry film thickness of the conversion layer coating is 3 micrometers, the dry film thickness of the cold spray zinc coating is 15 micrometers, and the dry film thickness of the single-component nano-composite silicone resin coating is 10 micrometers.

[0052] Example 12 A preparation process for a coating material for an electrical control device in coastal wind power equipment: The difference from Example 1 is that the dry film thickness of the conversion layer coating is 8 micrometers, the dry film thickness of the cold spray zinc coating is 30 micrometers, and the dry film thickness of the single-component nanocomposite silicone resin coating is 18 micrometers.

[0053] Comparative Example 1 A preparation process for a coating material for electrical control devices in coastal wind power equipment: the difference from Example 1 is that low-temperature plasma treatment is not performed.

[0054] Comparative Example 2 A preparation process for a coating material for an electrical control device in coastal wind power equipment: The difference from Example 1 is that the low-temperature plasma treatment time is 15 seconds.

[0055] Comparative Example 3 A preparation process for a coating material for electrical control devices in coastal wind power equipment: The difference from Example 1 is that the low-temperature plasma treatment time is 150 seconds.

[0056] Comparative Example 4 A preparation process for a coating material for electrical control devices in coastal wind power equipment: The difference from Example 1 is that no conversion layer coating is sprayed, but only a two-layer structure of cold spray zinc coating and single-component nano-composite silicone resin coating is used.

[0057] Comparative Example 5 A preparation process for a coating material for electrical control devices in coastal wind power equipment: The difference from Example 1 is that no cold spray zinc coating is applied, but only a two-layer structure of conversion coating and single-component nano-composite silicone resin coating is used.

[0058] Comparative Example 6 A preparation process for a coating material for electrical control devices in coastal wind power equipment: The difference from Example 1 is that a single-component nano-composite silicone resin coating is not sprayed, but a double-layer structure of conversion layer coating and cold spray zinc layer coating is used.

[0059] Detection methods Adhesion: Refer to GB / T 9286-1998 "Cross-cut test for paint and varnish film", use a 1mm gap cross-cut tester and 3M 600 tape for testing, and rate the grade (0 is the best, 5 is the worst).

[0060] Neutral salt spray resistance: The test was conducted in a salt spray chamber (5% NaCl solution, 35±2℃) according to GB / T 1771-2007 "Determination of neutral salt spray resistance of paints and varnishes". The time it took for red rust to appear on the substrate was recorded. For samples with "X"-shaped scratches (scratched to the substrate), the maximum erosion width on one side of the scratch was measured after 1000 hours of testing.

[0061] Electrical insulation: The volume resistivity of the coating was tested using a high resistance meter at a DC voltage of 500V, in accordance with GB / T 1410-2006 "Test methods for volume resistivity and surface resistivity of solid insulating materials".

[0062] Moist heat resistance: Refer to GB / T 1740-2007 "Test Method for Moist Heat Resistance of Coating Film" and conduct the test in a constant temperature and humidity chamber (temperature 47±1℃, relative humidity 96±2%). After 1000 hours, evaluate whether the coating has blistering, rusting, peeling and other phenomena.

[0063] Water resistance: The sample was completely immersed in deionized water at 25±1℃ for 30 days. After soaking, it was removed, dried, and the appearance of the coating was checked and the adhesion was tested.

[0064] Coating hardness: Refer to GB / T 6739-2006 "Determination of paint film hardness by pencil method" and use Zhonghua brand drawing pencil for testing.

[0065] Hydrophobicity (static contact angle): Using a contact angle meter, 5 μL of deionized water was dropped at different locations on the coating surface, the static water contact angle was measured, and the average value was taken.

[0066] Adhesion (cross-cut test) Resistance to neutral salt spray (time to red rust, h) Salt spray etched erosion width (mm) Volume resistivity (Ω·m) Resistance to damp heat (1000h) Water resistance (30-day immersion) Coating hardness Static water contact angle (°) Example 1 Level 0 >3000 <1.5 8.7×10¹³ In good condition, level 0 In good condition, level 0 4H 112 Example 2 Level 0 >2000 <2.0 5.2×10¹³ In good condition, level 0 In good condition, level 0 3H 108 Example 3 Level 0 >3000 <1.2 9.5×10¹³ In good condition, level 0 In good condition, level 0 5H 115 Example 4 Level 0 >2800 <1.8 8.3×10¹³ In good condition, level 0 In good condition, level 0 4H 110 Example 5 Level 0 >3000 <1.3 8.9×10¹³ In good condition, level 0 In good condition, level 0 5H 113 Example 6 Level 0 >2500 <2.2 6.8×10¹³ In good condition, level 0 In good condition, level 0 3H 105 Example 7 Level 0 >3000 <1.5 7.9×10¹³ In good condition, level 0 In good condition, level 0 4H 109 Example 8 Level 0 >3000 <1.0 9.1×10¹³ In good condition, level 0 In good condition, level 0 4H 114 Example 9 Level 1 >2200 <2.5 7.0×10¹³ Slight bubbling at the edges In good condition, Level 1 3H 102 Example 10 Level 1 >1800 <3.0 4.5×10¹² In good condition, Level 1 Slight bubbling at the edges 2H 98 Example 11 Level 1 >1500 <3.5 5.8×10¹³ In good condition, Level 1 In good condition, Level 1 3H 106 Example 12 Level 0 >3000 <1.8 8.5×10¹³ In good condition, level 0 In good condition, level 0 4H 111 Comparative Example 1 Level 2 480 The spread is severe (>10). 2.1×10¹² Large-area blistering and peeling Severe blistering and peeling 2H 95 Comparative Example 2 Level 1 1200 <5.0 6.5×10¹² Localized small blisters Bubbling at the edges 3H 103 Comparative Example 3 Level 1 1100 <5.5 5.9×10¹² Localized small blisters Bubbling at the edges 3H 101 Comparative Example 4 Level 3 (detached from the substrate) 720 Rapid expansion along the scratch 3.0×10¹² Severe blistering and substrate corrosion Severe blistering and peeling 2H 105 Comparative Example 5 Level 0 1500 <4.0 7.8×10¹³ In good condition, Level 1 In good condition, Level 1 4H 110 Comparative Example 6 Level 0 >2000 - <![CDATA[1.5×10 8 ]]> - Surface turns white and loses its luster 3H 68 As can be seen from Example 1 and Comparative Example 1, and Table 1, Comparative Example 1, which did not undergo low-temperature plasma treatment, showed a significant decrease in adhesion to level 2, a sharp deterioration in neutral salt spray resistance to only 480 hours, and severe failure in resistance to damp heat and water. This fully demonstrates that the low-temperature plasma treatment with optimized parameters used in this application plays an indispensable and crucial role in establishing an active interface with ultra-high adhesion on the circuit board substrate.

[0067] Combining Example 1 and Comparative Examples 4, 5, and 6 with Table 1, it can be seen that the comparative examples lacking any one layer all have serious shortcomings in their overall protective performance. Comparative Example 4, without a conversion layer, has extremely poor adhesion; Comparative Example 5, without a cold-sprayed zinc layer, lacks sacrificial anode protection and its salt spray resistance is far inferior to the complete system; Comparative Example 6, without a surface layer, completely loses its high insulation and weather resistance. This indicates that the three-layer composite structure designed in this application functions synergistically and each layer is indispensable.

[0068] Combining Examples 1, 2, and 3 with Table 1, it can be seen that adjusting the solid content of the conversion layer coating within the range of 35% to 50% resulted in coatings that maintained excellent adhesion and protective performance. Among them, Example 3, with its high solid content, exhibited superior hardness and density. This demonstrates that this formulation range not only ensures the core functionality but also provides flexibility for adjusting the physical properties of the coating.

[0069] As can be seen from Examples 1, 4, and 5, and in conjunction with Table 1, the key performance indicators of the conversion layers prepared using different types of phosphates are at the same excellent level as those of Example 1, which uses a phosphate compound. This verifies the substitutability of the types of phosphates described in the claims and the inclusiveness of the technical solutions.

[0070] As can be seen from Examples 1, 6, and 7, and in conjunction with Table 1, when the mixed resin ratio in the cold-sprayed zinc layer varies from 2.5:1 to 3.5:1 and the zinc content varies from 80% to 90%, the coating can provide excellent salt spray protection for over 2500 hours. This indicates that the formulation range can effectively balance the electrochemical protective capability and physical and mechanical properties of the coating.

[0071] As can be seen from Examples 1, 8, and 9, and in conjunction with Table 1, the zinc powder particle size has a significant impact on coating performance. Example 8, using a finer particle size, exhibits performance comparable to or even slightly better than Example 1, while Example 9, using a coarser particle size, shows an observable decrease in adhesion and resistance to damp heat. This demonstrates the necessity of limiting the zinc powder particle size D50 to 3-15 micrometers to ensure the overall performance of the coating.

[0072] As can be seen from Examples 1 and 10, and Table 1, after replacing the single-component nanocomposite silicone resin coating prepared by the method of this application with a commercially available silicone topcoat, the insulation performance, salt spray resistance, and hydrophobicity of Example 10 all showed significant deterioration. This highlights the key contribution of the topcoat preparation method described in this application to obtaining high-performance functional topcoats.

[0073] As can be seen from Examples 1, 11, and 12, and in conjunction with Table 1, the coating system maintains excellent overall protective performance when the thickness of each layer and the total dry film is near the lower and upper limits defined in claim 7. This demonstrates the rationality and feasibility of setting this thickness range, providing selection space for different protection levels.

[0074] As can be seen from Example 1, Comparative Examples 2 and 3, and Table 1, both excessively short and excessively long low-temperature plasma treatment times result in lower coating adhesion and various protective properties compared to Example 1. This confirms that optimizing the treatment time to within the range of 30-120 seconds is a necessary process condition to obtain the best interface activation effect and thus ensure coating performance.

[0075] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A coating material for electrical control devices in coastal wind power equipment, characterized in that, The coating material is a three-layer composite structure sequentially constructed on the surface of the circuit board substrate. The coating material includes a conversion layer coating adhered to the surface of the substrate, a cold spray zinc layer coating coated on the conversion layer, and a single-component nano-composite silicone resin coating coated on the surface of the cold spray zinc coating. The conversion layer coating includes an epoxy resin-based coating containing phosphates. The total dry film thickness of the coating is 28 to 56 micrometers.

2. The coating material for electrical control devices in coastal wind power equipment according to claim 1, characterized in that, The components of the conversion coating, by mass percentage, include 35%-50% epoxy resin, 5%-15% phosphate, 0.5%-2% a compound of benzotriazole and γ-glycidyl etheroxypropyltrimethoxysilane, 1%-3% nano silica, 0.2%-0.8% polyether-modified organosilicon, and the balance being propylene glycol methyl ether acetate.

3. The coating material for electrical control devices in coastal wind power equipment according to claim 2, characterized in that, The phosphate includes at least one of zinc phosphate, iron phosphate, or manganese phosphate.

4. The coating material for electrical control devices in coastal wind power equipment according to claim 1, characterized in that, The components of the cold-sprayed zinc coating, by mass percentage, include 80%-90% zinc powder, 8%-15% mixed resin, 0.5%-1.5% fumed silica, 0.3%-1% zinc fatty acid, and the balance being a mixture of xylene and n-butanol. The mixed resin is a compound of acrylic resin and epoxy resin in a mass ratio of (2.5-3.5):

1.

5. The coating material for electrical control devices in coastal wind power equipment according to claim 4, characterized in that, The zinc powder has a particle size D50 of 3 to 15 micrometers.

6. The coating material for electrical control devices in coastal wind power equipment according to claim 1, characterized in that, The preparation method of the single-component nanocomposite silicone resin coating includes the following steps: Nano-silica was dispersed in a solvent, and a silane coupling agent was added to carry out a surface grafting reaction to obtain a modified nanoparticle dispersion. Under an inert atmosphere, at least one alkoxysilane monomer undergoes a hydrolysis-condensation reaction to form an organosilicon prepolymer. The modified nanoparticle dispersion was uniformly mixed with the organosilicon prepolymer under shear force, and then a curing catalyst and additives were added. After degassing treatment, the single-component nanocomposite silicone resin coating was obtained.

7. The coating material for electrical control devices in coastal wind power equipment according to claim 1, characterized in that, The dry film thickness of the conversion layer coating is 3 to 8 micrometers, the dry film thickness of the cold spray zinc coating is 15 to 30 micrometers, and the dry film thickness of the single-component nanocomposite silicone resin coating is 10 to 18 micrometers.

8. A preparation process for a coating material for an electrical control device in coastal wind power equipment as described in any one of claims 1 to 7, characterized in that, Includes the following steps: The surface of the circuit board substrate is cleaned and roughened. The surface cleanliness of the substrate after treatment reaches Sa 2.5 level, and the surface roughness Ra is 20 to 50 micrometers. The surface of the substrate after treatment is then subjected to low-temperature plasma treatment for 30-120 seconds. A conversion layer coating is applied to the activated substrate surface. After the conversion layer coating is surface dry, a cold spray zinc coating is applied. After the cold spray zinc coating is surface dry, a single-component nano-composite silicone resin coating is applied. A staged curing process is adopted, curing at 20-30℃ for 4-8 hours, then curing at 40-60℃ for 2-4 hours, and then continuing to cure at 20-30℃ for a total time of not less than 24 hours.