A wear-resistant and anti-erosion multi-layer composite coating, a preparation method and application thereof

Abstract

The present application relates to the technical field of wear-resistant coating, and particularly relates to a wear-resistant and erosion-resistant multilevel composite coating, a preparation method and application. The wear-resistant and erosion-resistant multilevel composite coating comprises a polyurethane base layer and a photocuring resin layer loaded on the polyurethane base layer; and the photocuring resin layer contains a particle reinforced zone. The present application realizes excellent wear resistance and erosion resistance by the composite structure of the polyurethane base and the photocuring resin layer, and the particle reinforced zone is constructed in the photocuring resin layer. The wear-resistant and erosion-resistant multilevel composite coating of the present application can be formed by a simple spraying process, and is particularly suitable for irregular surfaces and complex curved surfaces. The present application overcomes the problems of the existing wear-resistant coating, such as insufficient erosion resistance under high-speed working conditions, complex preparation process and difficulty in uniform application on complex curved workpieces. The present application can be widely applied to the protection of the surfaces of high-speed rotating parts such as wind turbine blades, helicopter / unmanned aerial vehicle propellers, marine propellers and engine blades.

Description

Technical Field

[0001] This invention relates to the technical field of wear-resistant coatings, specifically to a wear-resistant and erosion-resistant multi-layer composite coating, its preparation method, and its application. Background Technology

[0002] Wear-resistant coatings are a key technology applied to the surface of a substrate to enhance its resistance to wear. In high-speed operating or high-speed fluid environments, workpiece surfaces are often subjected to continuous high-speed impacts from solid particles or droplets, leading to severe erosion wear. This wear can cause coating peeling, substrate damage, and consequently, decreased equipment performance, shortened lifespan, and increased maintenance costs. Wear-resistant coatings are widely used in many engineering fields. In everyday life, they are used in automotive engine components, high-speed train braking systems, etc., to reduce wear caused by friction and particle impact. In the military and high-end equipment fields, this wear-resistant coating is crucial for high-speed components such as aircraft engine blades, helicopter rotors, and ship propellers, effectively resisting erosion from sand, rainwater, or ocean waves, ensuring the reliability and durability of equipment in harsh environments. Furthermore, in the energy sector, wear-resistant coatings also significantly improve the long-term operational stability and efficiency of components such as wind turbine blades and hydraulic turbine flow components. In summary, wear-resistant coatings significantly improve the durability and reliability of key components in high-speed erosion environments, extending equipment lifespan and reducing maintenance costs. This makes a significant contribution to enhancing the performance of modern equipment, ensuring operational safety, and promoting the sustainable development of engineering technologies.

[0003] Wear-resistant coatings typically employ metal, ceramic, or polymer material systems, and their composition and structure are designed to address wear problems caused by high-speed particle or droplet erosion. Existing technologies focus on improving performance by enhancing coating adhesion, environmental adaptability, or additional functionalities. For example, CN 121344597A addresses the challenge of low bonding strength between the cladding layer and a specific substrate by designing a CuSn transition layer and a multi-layer gradient structure on a copper-zirconium alloy substrate; CN 120575116A utilizes a dual-ceramic layer system to improve the coating's oxidation resistance, thermal shock resistance, and friction reduction performance over a wide temperature range; and CN 120966361A develops a composite coating with a polymer resin matrix and added lubricating and reinforcing phases, which significantly improves the vibration and noise reduction (NVH) characteristics of gear components while providing wear resistance.

[0004] These innovative designs have improved the durability or functionality of coatings in specific application scenarios, but they still have limitations when dealing with extreme conditions of high-speed and high-frequency erosion: for example, complex gradient coating processes are costly, ceramic systems are prone to microcracks due to insufficient toughness, and polymer coatings have limited temperature resistance and load-bearing capacity. They are difficult to balance high hardness, toughness, excellent bonding strength and long-term erosion resistance, which limits their reliable application in key components of high-end high-speed equipment. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a wear-resistant and erosion-resistant multi-layer composite coating, its preparation method, and its application. The wear-resistant and erosion-resistant multi-layer composite coating of this invention consists of a polyurethane substrate layer and a photocurable resin layer loaded on the polyurethane substrate layer, with the photocurable resin layer containing particle reinforcement regions. This wear-resistant and erosion-resistant multi-layer composite coating exhibits an extremely low coefficient of friction (average coefficient of friction 0.06) and high erosion resistance (only 0.18% erosion mass loss after 30 minutes). The composite structure of the polyurethane substrate layer and the photocurable resin layer is constructed through a two-step spraying process, and a hard ceramic particle reinforcement region is built within the photocurable resin layer. This allows the photocurable resin matrix to provide adhesion and buffering, while the ceramic particles act as the main carrier, forming a synergistic mechanism. This overcomes the problems of insufficient erosion resistance under high-speed operating conditions, complex preparation processes, and difficulty in uniformly applying the coating to complex curved surfaces in existing technologies. Thus, it achieves a synergistic improvement in both low coefficient of friction and high erosion resistance, and can be uniformly formed on complex curved surfaces using a simple spraying process.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first objective of this invention is to provide a wear-resistant and erosion-resistant multi-layer composite coating, comprising: The system comprises a polyurethane substrate layer with a thickness of 10 μm to 1000 μm, and a photocurable resin layer with a thickness of 10 μm to 1000 μm loaded on the polyurethane substrate layer. The photocurable resin layer contains particle-reinforcing regions that extend longitudinally from the surface of the photocurable resin layer to a depth of 10 μm to 100 μm. This depth ensures both sufficient silane coupling agent-modified ceramic particle content on the surface of the photocurable resin layer and effective light penetration and curing of the photocurable resin layer.

[0007] The particle-reinforced region contains silane coupling agent-modified ceramic particles coated with photocurable resin, and the mass fraction of silane coupling agent-modified ceramic particles in the photocurable resin layer is 10%~50%.

[0008] Preferably, the depth of the particle enhancement region is 50μm~100μm.

[0009] Preferably, by weight fraction, the photocurable resin is composed of 15 to 20 parts resin matrix, 15 to 20 parts diluent TPGDA, 0.8 to 1 part leveling agent, 3.5 to 4 parts adhesion promoter, 0.8 to 1 part thixotropic agent, 0.1 to 0.2 parts polymerization inhibitor, 1 to 2 parts matting agent, 1 to 2 parts defoamer, and 1 to 2 parts photoinitiator TMO; wherein the resin matrix is ​​selected from epoxy resin, acrylate, or polyurethane.

[0010] Preferably, the silane coupling agent modified ceramic particles are prepared according to the following steps: S1. Ceramic particles are dispersed in a surface modifier and subjected to a surface activation reaction. Through oxidation and hydrolysis, an active hydroxyl group that can be used for condensation reaction is coated on the surface of the ceramic particles to obtain pretreated ceramic particles. The surface modifier is selected from a 10% (w / w) solution of hydrogen peroxide, dilute hydrochloric acid, or dilute nitric acid. The mass ratio of ceramic particles to hydrogen peroxide is 2-4:1.

[0011] S2. Disperse the pretreated ceramic particles in a mixed solution of water and ethanol, then add a silane coupling agent and perform hydrolysis and grafting reactions of the silane coupling agent. The hydrolysis of the silane coupling agent generates active silanol groups, which react with the hydroxyl groups on the surface of the pretreated ceramic particles to undergo a dehydration reaction, thereby obtaining silane coupling agent modified ceramic particles. The volume ratio of water to ethanol is 1:1, and the mass ratio of pretreated ceramic particles to silane coupling agent is 1~2:1.

[0012] The ceramic particles are selected from at least one of alumina, silicon carbide, silicon dioxide, silicon nitride, titanium nitride, aluminum nitride, boron nitride, zirconium oxide, titanium dioxide, and tungsten carbide; the silane coupling agent is selected from KH560 or KH570.

[0013] Preferably, the particle size of the ceramic particles is 15nm~5μm; if the particle size of the ceramic particles is too small, they are prone to agglomeration and easy to fall off after friction; if the particle size of the ceramic particles is too large, the spraying difficulty increases and the surface of the wear-resistant and erosion-resistant multi-level composite coating is rougher.

[0014] Preferably, the surface activation reaction and the hydrolysis and grafting reaction of the silane coupling agent are under the same conditions, namely, stirring at 90°C for 6 to 24 hours.

[0015] The second objective of this invention is to provide a method for preparing the above-mentioned wear-resistant and erosion-resistant multilayer composite coating, comprising the following steps: S1. Load a light-cured resin onto the surface of a polyurethane substrate to form an uncured resin layer.

[0016] S2. Spray silane coupling agent modified ceramic particles onto the surface of the uncured resin layer, so that the silane coupling agent modified ceramic particles are embedded in the surface of the uncured resin layer to form a particle reinforcement region, thus obtaining an uncured resin layer containing the particle reinforcement region.

[0017] S3. The uncured resin layer containing the particle reinforcement region is subjected to photocuring treatment, so that the silane coupling agent modified ceramic particles are encapsulated and fixed in the photocured resin layer from the surface to a depth of 0μm~100μm.

[0018] Preferably, a pneumatic spray gun is used to load the photocurable resin, wherein the air pressure is 0.4MPa~0.8MPa.

[0019] Preferably, electrostatic spray gun or pneumatic spray gun is used for spraying; wherein, when using electrostatic spray gun, the voltage is 60kV~80kV and the air pressure is 0.4MPa~0.8MPa.

[0020] Preferably, the conditions for photocuring are: irradiation under ultraviolet light with a wavelength of 365nm~405nm for 1min~5min.

[0021] The third objective of this invention is to provide the application of the above-mentioned wear-resistant and erosion-resistant multi-level composite coating in the surface protection of high-speed rotating components, including wind turbine blades, helicopter propellers, drone propellers, marine propellers, aero-engine blades, or gas turbine blades.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides a wear-resistant and erosion-resistant multi-layer composite coating, comprising a polyurethane substrate layer and a photocurable resin layer loaded on the polyurethane substrate layer; the photocurable resin layer contains particle reinforcement regions extending longitudinally from the surface of the photocurable resin layer to a depth of 0μm~100μm; the particle reinforcement regions contain silane coupling agent modified ceramic particles encapsulated by the photocurable resin. This invention constructs a synergistic mechanism of hard load-bearing and flexible buffering by uniformly coating and fixing the silane coupling agent modified ceramic particles in the photocurable resin layer: during friction, the photocurable resin matrix plays a bonding and buffering role, while the silane coupling agent modified ceramic particles act as the main mechanical load-bearing phase. The synergistic effect of these two components not only endows the wear-resistant and erosion-resistant multi-layer composite coating with an extremely low initial coefficient of friction, but also achieves high stability of the coefficient during continuous friction.

[0023] This is because the protruding parts of the silane coupling agent modified ceramic particles distributed on the surface of the photocurable resin layer directly bear the friction load, effectively resisting the cutting and plowing action of abrasive particles; at the same time, the resin matrix in the photocurable resin layer firmly coats the silane coupling agent modified ceramic particles, preventing them from peeling off or the friction interface from becoming rough, thus ensuring long-term, stable, and excellent wear resistance and friction reduction performance.

[0024] 2. The present invention also provides a method for preparing a wear-resistant and erosion-resistant multi-layer composite coating, comprising: loading a photocurable resin onto the surface of a polyurethane substrate to form an uncured resin layer; spraying silane coupling agent modified ceramic particles onto the surface of the uncured resin layer to form a particle reinforcement region, thereby obtaining an uncured resin layer containing the particle reinforcement region; and subjecting the uncured resin layer containing the particle reinforcement region to photocuring treatment to obtain a wear-resistant and erosion-resistant multi-layer composite coating.

[0025] The preparation process of this invention is extremely simple, requiring only two steps: spraying (a photocurable resin layer and silane coupling agent-modified ceramic particles) followed by photocuring. This method has low equipment requirements, a wide process window, and is easy to implement and scale up for production. In particular, this spraying process can perfectly adapt to workpiece surfaces with irregular shapes, complex curved surfaces, or fine structures, achieving uniform and complete coating coverage. It effectively solves the problems of traditional hard coating technologies, such as difficulty in coating complex geometric workpieces, uneven adhesion, or the need for complex post-processing, greatly expanding the application scenarios of high-performance wear-resistant coatings. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the wear-resistant and erosion-resistant multi-level composite coating of the present invention.

[0027] Figure 2 The images shown are SEM images of the wear-resistant and erosion-resistant multi-layer composite coating of Example 1, where (a) is the overall structure diagram, (b) is the aluminum element distribution diagram, (c) is a low-magnification image of the interface between the polyurethane substrate layer and the photocurable resin layer, (d) is a high-magnification image of the interface between the polyurethane substrate layer and the photocurable resin layer, (e) is a low-magnification image of the particle reinforcement region, and (f) is a high-magnification image of the particle reinforcement region.

[0028] Figure 3 The graph shows the change in friction coefficients of the polyurethane base film, the wear-resistant and erosion-resistant multilayer composite coating of Example 1, and the multilayer composite coating of Comparative Example 1 during the friction and wear process.

[0029] Figure 4 The thermogravimetric curve of the wear-resistant and erosion-resistant multi-layer composite coating in Example 1 is shown.

[0030] Explanation of reference numerals in the attached figures: 1. Particle-reinforced region, 2. Photocurable resin layer, 3. Polyurethane base layer. Detailed Implementation

[0031] The technical solution of the present invention will be clearly and completely described below with reference to the data in 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.

[0032] It should be noted that the technical terms used in this invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of this invention. Unless otherwise specified, all raw materials, reagents, instruments and equipment used in the following embodiments of this invention can be purchased on the market or prepared by existing methods.

[0033] like Figure 1 As shown, the present invention provides a wear-resistant and erosion-resistant multi-layer composite coating, including a polyurethane substrate layer 3 and a photocurable resin layer 2 loaded on the polyurethane substrate layer 3; the photocurable resin layer 2 contains a particle reinforcement region 1, which extends inward from the surface of the photocurable resin layer 2 in the longitudinal direction to a depth of 0μm~100μm, and the particle reinforcement region 1 contains silane coupling agent modified ceramic particles encapsulated by the photocurable resin.

[0034] The thickness of the polyurethane substrate layer 3 is 10μm~1000μm, and the thickness of the photocurable resin layer 2 is 10μm~1000μm.

[0035] After curing, the UV-cured resin layer 2 has a smooth surface, which can be well bonded to the polyurethane base layer 3; and the polyurethane base layer 3 has very good adhesion, making it easy to bond with the substrate to be protected and the UV-cured resin.

[0036] In particle reinforcement zone 1, the silane coupling agent modified ceramic particles are bonded to the photocurable resin through the silane coupling agent, which significantly enhances the wear resistance and surface strength of the wear-resistant and erosion-resistant multi-level composite coating.

[0037] In wear-resistant and erosion-resistant multi-layer composite coatings, the content of silane coupling agent-modified ceramic particles is 10%~50% by mass (e.g., Figure 4 (As shown).

[0038] The UV-cured resin is sprayed using a pneumatic spray gun; the silane coupling agent modified ceramic particles are sprayed using an electrostatic spray gun or a pneumatic spray gun.

[0039] To enable those skilled in the art to more clearly understand the technical solution of the present invention, the following will provide a detailed description in conjunction with specific embodiments: Example 1 A method for preparing a wear-resistant and erosion-resistant multi-layer composite coating includes the following steps: S1. Preparation of silane coupling agent modified ceramic particles: Alumina particles with a diameter of 1 μm were dispersed in a 10% hydrogen peroxide solution and stirred for 6 h in a water bath at 90 °C. After centrifugation, the alumina was washed three times alternately with deionized water and ethanol, and then dried at 80 °C for 24 h to obtain pretreated alumina. The mass ratio of alumina to hydrogen peroxide was 4:1.

[0040] Pretreated alumina was added to a mixed solution of water and ethanol in a 1:1 volume ratio, followed by the addition of KH560 to obtain a dispersion. The dispersion was stirred in a 90°C water bath for 24 hours, centrifuged, and then washed three times alternately with deionized water and ethanol. Finally, it was dried at 80°C for 24 hours to obtain KH560-modified alumina, i.e., silane coupling agent-modified ceramic particles. The mass ratio of pretreated alumina, water, ethanol, and KH560 was 4:5:5:2.

[0041] S2. Preparation of UV-cured epoxy resin: 20 parts epoxy resin, 15 parts diluent TPGDA and 0.8 parts leveling agent were added sequentially to a dispersion container and mechanically stirred for 30 minutes to obtain a premix. 4 parts adhesion promoter, 0.8 parts thixotropic agent, 0.1 parts polymerization inhibitor, 1 part matting agent and 1 part defoamer were added to the premix. After mechanical stirring for 80 minutes, 2 parts photoinitiator TMO were added and stirring was continued for 130 minutes until all components were fully dissolved and mixed evenly to obtain a photocurable epoxy resin.

[0042] S3. Preparation of wear-resistant and erosion-resistant multi-layer composite coating: A pneumatic spray gun was used to uniformly spray UV-cured epoxy resin onto the surface of a polyurethane substrate. The spraying pressure was controlled at 0.6 MPa, and the spraying time was 10 s, forming an uncured resin layer. The thickness of the polyurethane substrate was 300 μm, and the thickness of the uncured resin layer was 200 μm. Subsequently, an electrostatic spray gun was used to spray KH560 modified alumina onto the uncured resin layer. The spraying time was 20 s, and the working voltage of the electrostatic spray gun was set to 70 kV, with the air pressure maintained at 0.6 MPa. The KH560 modified alumina formed a continuous and uniform spread layer on the surface of the uncured resin layer. The spread layer surface was smooth and free of defects visible to the naked eye. After spraying, it was irradiated under a 405 nm UV lamp for 2 min to fully cure, resulting in a wear-resistant and erosion-resistant multi-layered composite coating with a total thickness of 500 μm. The mass fraction of KH560 modified alumina in the wear-resistant and erosion-resistant multi-layered composite coating was 30%.

[0043] Figure 2 The results show that the wear-resistant and erosion-resistant multilayer composite coating has a total thickness of 500 μm, comprising a polyurethane layer, a UV-cured epoxy resin layer, and a particle-reinforced region. There is good interlayer bonding between the polyurethane layer and the UV-cured epoxy resin layer. In the particle-reinforced region, KH560 modified alumina is tightly encapsulated within the resin.

[0044] Figure 4 The results show that the mass fraction of KH560 modified alumina in the wear-resistant and erosion-resistant multi-layer composite coating is 30%.

[0045] Example 2 A method for preparing a wear-resistant and erosion-resistant multi-layer composite coating is the same as that in Example 1, except that the spraying method of KH560 modified alumina in step S3 is changed from an electrostatic spray gun to a pneumatic spray gun, as detailed below: S3. Preparation of wear-resistant and erosion-resistant multi-layer composite coating: A UV-cured epoxy resin was uniformly sprayed onto the surface of a polyurethane substrate using a pneumatic spray gun. The spraying pressure was controlled at 0.6 MPa, and the spraying time was 10 s, forming an uncured resin layer. The thickness of the polyurethane substrate was 300 μm, and the thickness of the uncured resin layer was 200 μm. Subsequently, KH560 modified alumina was sprayed onto the uncured resin layer using another pneumatic spray gun. The spraying time was 10 s, and the air pressure was maintained at 0.6 MPa. The KH560 modified alumina formed a continuous and uniform spread layer on the surface of the uncured resin layer. The spread layer surface was smooth and free of defects visible to the naked eye. After spraying, it was irradiated under a 405 nm UV lamp for 2 min to fully cure, resulting in a wear-resistant and erosion-resistant multi-layered composite coating with a total thickness of 500 μm. The mass fraction of KH560 modified alumina in the wear-resistant and erosion-resistant multi-layered composite coating was 30%.

[0046] Example 3 A method for preparing a wear-resistant and erosion-resistant multi-layer composite coating includes the following steps: S1. Preparation of silane coupling agent modified ceramic particles: Silica with a particle size of 500 nm was dispersed in a 10% hydrogen peroxide solution and stirred for 6 h under a water bath heating condition at 90 °C. After centrifugation, it was washed three times alternately with deionized water and ethanol, and then dried at 80 °C for 24 h to obtain pretreated silica. The mass ratio of silica particles to hydrogen peroxide was 2:1.

[0047] Pretreated silica was added to a mixed solution of water and ethanol in a 1:1 volume ratio, followed by the addition of silane coupling agent KH570 to obtain a dispersion. The dispersion was stirred in a 90°C water bath for 24 hours, centrifuged, and then washed three times alternately with deionized water and ethanol. Finally, it was dried at 80°C for 24 hours to obtain KH570-modified silica, i.e., silane coupling agent-modified ceramic particles. The mass ratio of pretreated silica, water, ethanol, and KH570 was 2:5:5:2.

[0048] S2. Preparation of UV-cured acrylate: 20 parts of acrylate, 15 parts of diluent TPGDA, and 0.8 parts of leveling agent were added sequentially to a dispersion container and mechanically stirred for 30 minutes to obtain a premix. 4 parts of adhesion promoter, 0.8 parts of thixotropic agent, 0.1 parts of polymerization inhibitor, 1 part of matting agent, and 1 part of defoamer were added to the premix. After mechanical stirring for 80 minutes, 2 parts of photoinitiator TMO were added, and stirring was continued for 130 minutes until all components were fully dissolved and mixed evenly to obtain a photocurable acrylate.

[0049] S3. Preparation of wear-resistant and erosion-resistant multi-layer composite coating: A UV-cured acrylate was uniformly sprayed onto the surface of a polyurethane substrate using a pneumatic spray gun. The spraying pressure was controlled at 0.6 MPa, and the spraying time was 10 s, forming an uncured resin layer with a polyurethane substrate thickness of 300 μm and an uncured resin layer thickness of 200 μm. Subsequently, KH570 modified silica was sprayed onto the uncured resin layer using another pneumatic spray gun for 10 s, with the air pressure maintained at 0.6 MPa. The KH570 modified silica formed a continuous and uniform spread layer on the surface of the uncured resin layer. The spread layer surface was smooth and free of defects visible to the naked eye. After spraying, the coating was irradiated under a 405 nm UV lamp for 2 min to fully cure it, resulting in a wear-resistant and erosion-resistant multi-layered composite coating with a total thickness of 500 μm. The mass fraction of KH560 modified silica in the wear-resistant and erosion-resistant multi-layered composite coating was 20%.

[0050] Example 4 A method for preparing a wear-resistant and erosion-resistant multi-layer composite coating includes the following steps: S1. Preparation of silane coupling agent modified ceramic particles: S11. Alumina with a particle size of 150 nm was dispersed in a 10% hydrogen peroxide solution and stirred for 6 h under a water bath heating condition at 90 °C. After centrifugation, it was washed three times alternately with deionized water and ethanol, and then dried at 80 °C for 24 h to obtain pretreated alumina. The mass ratio of alumina to hydrogen peroxide was 2:1.

[0051] Pretreated alumina was added to a mixed solution of water and ethanol in a 1:1 volume ratio, followed by the addition of silane coupling agent KH560 to obtain a dispersion. The dispersion was stirred in a 90°C water bath for 24 hours, centrifuged, and then washed three times alternately with deionized water and ethanol. Finally, it was dried at 80°C for 24 hours to obtain KH560-modified alumina, i.e., silane coupling agent-modified ceramic particles. The mass ratio of pretreated alumina, water, ethanol, and KH560 was 2:5:5:2.

[0052] S12. Silica with a particle size of 500 nm is dispersed in a 10% hydrogen peroxide solution and stirred for 6 h under a water bath heating condition at 90 °C. After centrifugation, it is washed three times alternately with deionized water and ethanol, and then dried at 80 °C for 24 h to obtain pretreated silica. The mass ratio of silica to hydrogen peroxide is 2:1.

[0053] Pretreated silica was added to a mixed solution of water and ethanol in a 1:1 volume ratio, followed by the addition of silane coupling agent KH560 to obtain a dispersion. The dispersion was stirred in a 90°C water bath for 24 hours, centrifuged, and then washed three times alternately with deionized water and ethanol. Finally, it was dried at 80°C for 24 hours to obtain KH560-modified silica, i.e., silane coupling agent-modified ceramic particles. The mass ratio of pretreated silica, water, ethanol, and KH560 was 2:5:5:2.

[0054] S2. Preparation of UV-cured epoxy resin: 20 parts epoxy resin, 15 parts diluent TPGDA and 0.8 parts leveling agent were added sequentially to a dispersion container and mechanically stirred for 30 minutes to obtain a premix. 4 parts adhesion promoter, 0.8 parts thixotropic agent, 0.1 parts polymerization inhibitor, 1 part matting agent and 1 part defoamer were added to the premix. After mechanical stirring for 80 minutes, 2 parts photoinitiator TMO were added and stirring was continued for 130 minutes until all components were fully dissolved and mixed evenly to obtain a photocurable epoxy resin.

[0055] S3. Preparation of wear-resistant and erosion-resistant multi-layer composite coating: A pneumatic spray gun was used to uniformly spray UV-cured epoxy resin onto the surface of a polyurethane substrate. The spraying pressure was controlled at 0.6 MPa, and the spraying time was 10 s, forming an uncured resin layer with a polyurethane substrate thickness of 300 μm and an uncured resin layer thickness of 200 μm. Subsequently, an electrostatic spray gun was used to spray KH560 modified alumina onto the uncured resin layer. The electrostatic spray gun's operating voltage was set to 70 kV, the air pressure was maintained at 0.6 MPa, and the spraying time was 10 s, resulting in an uncured resin layer with KH560 modified alumina. Another electrostatic spray gun was used to spray KH560 modified alumina onto the uncured resin layer with KH560 modified alumina. The electrostatic spray gun was set to a working voltage of 70 kV and an air pressure of 0.6 MPa. The spraying time was the same as that for KH560 modified alumina. KH560 modified silica formed a continuous and uniform spread layer on the surface of the uncured resin layer containing KH560 modified alumina. The spread layer surface was smooth and free of visible defects. After spraying, it was irradiated under a 405 nm UV lamp for 2 minutes to fully cure, resulting in a wear-resistant and erosion-resistant multi-layered composite coating with a total thickness of 500 μm. The total mass fraction of KH560 modified alumina and KH560 modified silica in this multi-layered composite coating was 30%. The mass ratio of KH560 modified alumina to KH560 modified silica in the mixed particles was 1:1.

[0056] Example 5 A method for preparing a wear-resistant and erosion-resistant multi-layer composite coating includes the following steps: S1. Preparation of silane coupling agent modified ceramic particles: S11. Alumina with a particle size of 150 nm was dispersed in a 10% hydrogen peroxide solution and stirred for 6 h under a water bath heating condition at 90 °C. After centrifugation, it was washed three times alternately with deionized water and ethanol, and then dried at 80 °C for 24 h to obtain pretreated alumina. The mass ratio of alumina to hydrogen peroxide was 2:1.

[0057] Pretreated alumina was added to a mixed solution of water and ethanol in a 1:1 volume ratio, followed by the addition of silane coupling agent KH560 to obtain a dispersion. The dispersion was stirred in a 90°C water bath for 24 hours, centrifuged, and then washed three times alternately with deionized water and ethanol. Finally, it was dried at 80°C for 24 hours to obtain KH560-modified alumina, i.e., silane coupling agent-modified ceramic particles. The mass ratio of pretreated ceramic particles, water, ethanol, and KH560 was 2:5:5:2.

[0058] S12. Silicon carbide with a particle size of 500 nm was dispersed in a 10% hydrogen peroxide solution and stirred for 6 h under a water bath heating condition at 90 °C. After centrifugation, it was washed three times alternately with deionized water and ethanol, and then dried at 80 °C for 24 h to obtain pretreated silicon carbide. The mass ratio of silicon carbide to hydrogen peroxide was 2:1.

[0059] Pretreated silicon carbide was added to a mixed solution of water and ethanol in a 1:1 volume ratio, followed by the addition of silane coupling agent KH560 to obtain a dispersion. The dispersion was stirred in a 90°C water bath for 24 hours, centrifuged, and then washed three times alternately with deionized water and ethanol. Finally, it was dried at 80°C for 24 hours to obtain KH560-modified silicon carbide, i.e., silane coupling agent-modified ceramic particles. The mass ratio of pretreated silicon carbide, water, ethanol, and KH560 was 2:5:5:2.

[0060] S2. Preparation of UV-cured epoxy resin: 20 parts epoxy resin, 15 parts diluent TPGDA and 0.8 parts leveling agent were added sequentially to a dispersion container and mechanically stirred for 30 minutes to obtain a premix. 4 parts adhesion promoter, 0.8 parts thixotropic agent, 0.1 parts polymerization inhibitor, 1 part matting agent and 1 part defoamer were added to the premix. After mechanical stirring for 80 minutes, 2 parts photoinitiator TMO were added and stirring was continued for 130 minutes until all components were fully dissolved and mixed evenly to obtain a photocurable epoxy resin.

[0061] S3. Preparation of wear-resistant and erosion-resistant multi-layer composite coating: A pneumatic spray gun was used to uniformly spray UV-cured epoxy resin onto the surface of a polyurethane substrate. The spraying pressure was controlled at 0.6 MPa, and the spraying time was 10 s, forming an uncured resin layer. The thickness of the polyurethane substrate was 300 μm, and the thickness of the uncured resin layer was 200 μm. Subsequently, an electrostatic spray gun was used to spray a mixture of KH560 modified alumina and KH560 modified silicon carbide particles onto the uncured resin layer. The spraying time was 20 s, the working voltage of the electrostatic spray gun was set to 70 kV, and the air pressure was maintained at 0.6 MPa. The mixed particles formed a continuous and uniform spread layer on the surface of the uncured resin layer. The spread layer surface was smooth and free of defects visible to the naked eye. After spraying, it was irradiated under a 405 nm UV lamp for 2 min to fully cure, resulting in a wear-resistant and erosion-resistant multi-layered composite coating with a total thickness of 500 μm. The total mass fraction of KH560 modified alumina and KH560 modified silicon carbide in the wear-resistant and erosion-resistant multi-layered composite coating was 30%. In the mixed particles, the mass ratio of KH560 modified alumina to KH560 modified silicon carbide is 1:1.

[0062] Comparative Example 1 A method for preparing a multi-layer composite coating, the multi-layer composite coating comprising a polyurethane substrate layer and a photocurable resin layer loaded on the polyurethane substrate layer, comprising the following steps: S1. Preparation of UV-cured epoxy resin: 20 parts epoxy resin, 15 parts diluent TPGDA and 0.8 parts leveling agent were added sequentially to a dispersion container and mechanically stirred for 30 minutes to obtain a premix. 4 parts adhesion promoter, 0.8 parts thixotropic agent, 0.1 parts polymerization inhibitor, 1 part matting agent and 1 part defoamer were added to the premix. After mechanical stirring for 80 minutes, 2 parts photoinitiator TMO were added and stirring was continued for 130 minutes until all components were fully dissolved and mixed evenly to obtain a photocurable epoxy resin.

[0063] S2. Preparation of multi-level composite coatings: A pneumatic spray gun was used to uniformly spray UV-cured epoxy resin onto the surface of a polyurethane substrate. The spraying pressure was controlled at 0.6 MPa, the spraying time was 10 s, the thickness of the polyurethane substrate was 300 μm, and the thickness of the uncured resin layer was 200 μm. Subsequently, it was irradiated under a 405 nm UV lamp for 2 min to fully cure it, resulting in a multi-layered composite coating.

[0064] Static friction and wear tests were conducted using a UMT2 friction and wear testing machine. The load was 5 N, the friction stroke was 5 mm, the frequency was 0.5 Hz, and the friction time was 20 min. The upper friction pair was Si3N4, and the lower friction pair consisted of the wear-resistant and erosion-resistant multilayer composite coating of Example 1, the multilayer composite coating of Comparative Example 1, and a polyurethane substrate film. All samples used aluminum plates as substrates in the tests. The results showed that the wear-resistant and erosion-resistant multilayer composite coating (containing particle reinforcement regions) of this invention exhibited an extremely low coefficient of friction (<0.1, with an average coefficient of friction of 0.06 during the friction process), and remained stable during the 20 min of continuous friction without significant increase. Figure 3 As shown in the figure, the multi-layered composite coating of Comparative Example 1 (containing only a photocurable resin layer and no particle reinforcement region) showed a gradual increase in the coefficient of friction and significant surface damage during the friction process; while the polyurethane substrate film showed more rapid damage. This fully demonstrates the crucial role of the particle reinforcement region in maintaining the low coefficient of friction and wear resistance of the coating: the silane coupling agent modified ceramic particles distributed on the surface of the photocurable resin layer act as a carrier phase to directly resist abrasive cutting, while the firm coating of the resin matrix on the silane coupling agent modified ceramic particles prevents peeling and interface degradation, thereby achieving long-term stability of the coefficient of friction.

[0065] Dynamic erosion tests were conducted using a pneumatic spray gun at a pressure of 0.6 MPa, a nozzle diameter of 1.5 mm, and a nozzle-sample distance of 10 cm. The abrasive used was 60-mesh white corundum. The eroded samples were the wear-resistant and erosion-resistant multi-layer composite coating surface and the polyurethane film surface from Examples 1 to 5. After 30 minutes of erosion, obvious scratches and holes appeared on the polyurethane film surface; meanwhile, the wear-resistant and erosion-resistant multi-layer composite coating surface of Example 1 showed no significant change, with a mass reduction of only 0.18%, demonstrating excellent erosion resistance.

[0066] It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range, as well as any value between the two endpoints, can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described here to avoid redundancy. Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this invention.

Claims

1. A wear-resistant and erosion-resistant multi-layer composite coating, characterized in that, The wear-resistant and erosion-resistant multi-layer composite coating includes: Polyurethane substrate layer, with a thickness of 10μm~1000μm; And a photocurable resin layer loaded on the polyurethane substrate, with a thickness of 10μm~1000μm; The photocurable resin layer contains a particle reinforcement region, which extends inward from the surface of the photocurable resin layer to a depth of 10μm to 100μm along the longitudinal direction. The particle enhancement region contains silane coupling agent modified ceramic particles coated with the photocurable resin, and the mass fraction of the silane coupling agent modified ceramic particles in the photocurable resin layer is 10%~50%.

2. The wear-resistant and erosion-resistant multi-layer composite coating according to claim 1, characterized in that, By weight fraction, the photocurable resin is composed of 15 to 20 parts resin matrix, 15 to 20 parts diluent TPGDA, 0.8 to 1 part leveling agent, 3.5 to 4 parts adhesion promoter, 0.8 to 1 part thixotropic agent, 0.1 to 0.2 parts polymerization inhibitor, 1 to 2 parts matting agent, 1 to 2 parts defoamer and 1 to 2 parts photoinitiator TMO; The resin matrix is ​​selected from epoxy resin, acrylate or polyurethane.

3. The wear-resistant and erosion-resistant multi-layer composite coating according to claim 1, characterized in that, Silane coupling agent modified ceramic particles are prepared according to the following steps: Ceramic particles are dispersed in a surface modifier and subjected to a surface activation reaction to obtain pretreated ceramic particles; the mass ratio of ceramic particles to hydrogen peroxide is 2~4:1; the surface modifier is selected from 10% hydrogen peroxide, dilute hydrochloric acid or dilute nitric acid solution. Pretreated ceramic particles were dispersed in a mixed solution of water and ethanol, and then a silane coupling agent was added. The silane coupling agent was then subjected to hydrolysis and grafting reactions to obtain silane coupling agent modified ceramic particles. The volume ratio of water to ethanol was 1:1, and the mass ratio of pretreated ceramic particles to silane coupling agent was 1~2:

1. The ceramic particles are selected from at least one of alumina, silicon carbide, silicon dioxide, silicon nitride, titanium nitride, aluminum nitride, boron nitride, zirconium oxide, titanium dioxide, and tungsten carbide. The silane coupling agent is selected from KH560 or KH570.

4. The wear-resistant and erosion-resistant multi-layer composite coating according to claim 3, characterized in that, The conditions for the surface activation reaction and the hydrolysis and grafting reaction of the silane coupling agent are the same: stirring at 90℃ for 6h~24h.

5. The wear-resistant and erosion-resistant multi-layer composite coating according to claim 3, characterized in that, The ceramic particles have a particle size of 15nm~5μm.

6. A method for preparing the wear-resistant and erosion-resistant multi-layer composite coating as described in claim 1, characterized in that, Includes the following steps: A photocurable resin is loaded onto the surface of a polyurethane substrate to form an uncured resin layer. Silane coupling agent modified ceramic particles are sprayed onto the surface of the uncured resin layer to form a particle-reinforced region, resulting in an uncured resin layer containing the particle-reinforced region. An uncured resin layer containing particle reinforcement zones is subjected to photocuring to obtain a wear-resistant and erosion-resistant multi-layer composite coating.

7. The preparation method according to claim 6, characterized in that, The photocurable resin is loaded using a pneumatic spray gun with an air pressure of 0.4 MPa to 0.8 MPa.

8. The preparation method according to claim 6, characterized in that, The silane coupling agent modified ceramic particles are sprayed using an electrostatic spray gun or a pneumatic spray gun; when using an electrostatic spray gun, the voltage is 60kV~80kV and the air pressure is 0.4MPa~0.8MPa.

9. The preparation method according to claim 6, characterized in that, The conditions for photocuring are: irradiation under ultraviolet light with a wavelength of 365nm~405nm for 1min~5min.

10. The application of the wear-resistant and erosion-resistant multi-layer composite coating as described in claim 1 in the surface protection of high-speed rotating components, characterized in that, High-speed rotating components include wind turbine blades, helicopter propellers, drone propellers, marine propellers, aircraft engine blades, or gas turbine blades.

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