A multi-system powder reinforced thermal protection and vibration damping coating and a method for preparing the same

Abstract

The present application belongs to the technical field of light thermal insulation materials, and particularly relates to a multi-system powder enhanced thermal protection and vibration damping coating and a preparation method thereof. The method comprises the following steps: pretreating the surface of a thin-walled component, spraying a water-based polyurethane solution, vacuum drying to obtain a polyurethane matrix layer firmly attached to the substrate; spraying a silane coupling agent on the surface of the polyurethane matrix layer; alkali washing and drying nano performance enhancing powder to obtain hydroxylated nano powder, which is then sprayed onto the surface of the treated polyurethane matrix layer to form a powder enhanced layer; spraying a water-based polyurethane solution on the surface of the powder enhanced layer to form a covering layer, which covers the powder enhanced layer; and vacuum drying the sprayed component to obtain a composite coating with a structure of "polyurethane matrix layer-powder enhanced layer-polyurethane covering layer". The coating has a high damping effect, effectively realizes the vibration damping effect of the structural component, and does not significantly increase the mass of the structural component.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of light thermal insulation materials, and particularly relates to a multi-system powder enhanced thermal protection and vibration reduction coating and a preparation method thereof. BACKGROUND

[0002] To meet the extreme pursuit of high thrust-to-weight ratio and fuel efficiency of new generation of aviation equipment, thin-walled components taking light metal and composite material as the core are widely used in key parts of advanced aircraft and aero-engines. However, such thin-walled structures need to continuously withstand the combined action of high temperature, wideband vibration and corrosive medium erosion in the service process. Under the harsh conditions of thermal-mechanical-chemical multi-field coupling, the components face a series of severe challenges such as high-temperature failure, stiffness degradation, aggravated vibration fatigue damage and surface erosion aging, which seriously restrict their service safety and life.

[0003] Advanced coating technology is one of the key means to improve the performance and service life of such thin-walled components. By constructing a functional coating on the surface of the component, it can provide overall protection such as thermal protection, vibration reduction and corrosion resistance without changing the structure size, and has the advantages of flexible process, on-site operation and low maintenance cost. However, the coating materials widely used at present are mostly single-layer single-system structures, and the functions are relatively single. For example, traditional thermal protection coatings focus on heat insulation, but have poor damping performance and are easy to crack under vibration; while conventional vibration reduction coatings are difficult to withstand high temperature. This functional split makes it difficult for existing coatings to provide coordinated protection for components in complex thermal-vibration coupled environments, and cannot meet the requirements of modern aerospace equipment for high performance and high reliability.

[0004] The patent "Method for in-situ growth of large-thickness high-temperature-resistant / heat-insulating / radiation-heat-dissipating integrated thermal protection coating with multi-level gradient pore structure on thin-walled metal surface", publication number CN119411198A, publication date February 11, 2025, uses a micro-arc oxidation process that has very high requirements for electrolyte composition and electrical parameter control, and the process is complex and difficult to industrialize on a large scale. In addition, the multi-level gradient pore coating structure designed by it needs to be further verified in terms of thermal-vibration resistance and mechanical strength at high temperature.

[0005] The patent "Ultrahigh-temperature thermal protection powder coating, ultrahigh-temperature thermal protection coating, and preparation method and application thereof", publication number CN119410176A, publication date February 11, 2025, improves the ablation resistance of the coating by adding metal carbide to the transition metal boride and silicon carbide composite coating. However, the preparation process of the ultrahigh-temperature thermal protection powder coating involves spray drying and induction plasma spheroidization, which has high equipment cost and complex operation. In addition, although the ablation resistance of the coating is improved to a certain extent, its oxidation resistance in a thermal environment is not clear.

[0006] Patent "High-reflective heat protection coating and its preparation method", publication number CN120666283A, publication date September 19, 2025, uses LSTN0.125 ceramic powder with high reflectivity as coating raw material, but the coating corresponding powder material preparation process is complex, involving ball milling, spray granulation, pre-sintering and other multi-step operations, low production efficiency.

[0007] Patent "Reproducible ultra-high temperature heat protection coating", publication number CN119020718A, publication date November 26, 2024, uses double powder feeding atmospheric plasma spraying technology to prepare gradient structure coating. However, the double powder feeding process has high requirements for equipment precision and operator skills, and the process is complex and difficult to industrialize on a large scale, and its long-term stability at extremely high temperature still needs further verification. In addition, this method is mainly aimed at ceramic matrix composites, and its applicability to thin-walled components composed of metals or resins is insufficient.

[0008] Patent "High-temperature-resistant heat protection coating reinforced composite material and its preparation method", publication number CN120588527A, publication date September 5, 2025, by spraying functional materials and reinforcing agents on the fiber web, a coating material with high thermal insulation performance is prepared. However, the preparation process of the coating of this method involves ball milling, spray granulation, needling, sol-gel and other multi-step operations, and the process is complex and costly. Secondly, although the thermal insulation performance of the coating is improved to a certain extent, the mechanical strength and erosion resistance at high temperature are not considered; in addition, this method is mainly applied to the field of light thermal insulation materials, and its applicability to other fields is low.

[0009] Patent "Nanometer structure heat protection coating resistant to long-time high temperature oxidation and its preparation method", publication number CN119797917A, publication date April 11, 2025, uses spray granulation and solid phase sintering technology to prepare nanometer structure spherical powder. However, the preparation process of nanometer structure powder is complex, involving ball milling, spray granulation, solid phase sintering and other multi-step operations, low production efficiency and high cost. Secondly, the thermal shock resistance and mechanical strength of the coating material at extremely high temperature still need further verification.

[0010] Patent "Heat protection coating, its preparation method and application", publication number CN119736572A, publication date April 1, 2025, by introducing nano-particle reinforcement phase, the crack resistance and oxidation resistance of the coating are improved, but the preparation process of the coating involves multi-step spraying and complex material ratio, and the performance improvement of the coating is mainly concentrated in the aspects of oxidation resistance and crack resistance, and the thermal insulation performance and vibration resistance at high temperature are not considered.

[0011] Patent "Nuclear radiation resistant heat shield coating for steam pipeline and its preparation method", publication number CN119220173B, publication date December 31, 2024, uses the combination of organic coating and inorganic coating to improve the nuclear radiation resistance of the coating. However, this coating is mainly used for thermal protection of nuclear industry steam pipelines and does not consider the thermal shock resistance.

[0012] Although there have been many research and development attempts on thermal protection coatings in the prior art, there are still the following common problems:

[0013] Complex manufacturing process: Most solutions rely on processes such as micro-arc oxidation, plasma spraying, spray granulation combined with high-temperature sintering, which have high equipment requirements, precise parameter control, high energy consumption, and are difficult to scale up.

[0014] Narrow substrate applicability: Many processes (such as thermal spraying) are mainly designed for metal substrates and are not suitable for heat-sensitive thin-walled components such as fiber-reinforced resin matrix composites, which can easily damage the substrate.

[0015] Insufficient comprehensive performance verification: Existing technologies focus on improving a single performance of the coating (such as ablation resistance, oxidation resistance), and lack systematic evaluation and verification of the coating's thermal shock resistance, heat insulation and vibration reduction synergy, and long-term environmental durability in simulated real service environments.

[0016] In summary, developing a new multi-functional coating system that is relatively simple in process, suitable for various substrates (metal and composite materials), and can provide effective thermal protection and vibration reduction performance under thermal shock service conditions has become a technical bottleneck that needs to be broken through in the field. SUMMARY

[0017] To solve the problems in the prior art, the present application provides a multi-system powder enhanced thermal protection and vibration reduction coating and a preparation method thereof.

[0018] The technical solution of the present application is:

[0019] The present application discloses a preparation method of a multi-system powder enhanced thermal protection and vibration reduction coating, comprising the following steps:

[0020] S1, cleaning and silane coupling agent spraying pretreatment are performed on the surface of the thin-walled component to introduce coupling functional groups;

[0021] S2, a water-based polyurethane solution is sprayed on the surface of the pretreated thin-walled component to form a first polyurethane layer;

[0022] S3, the thin-walled component with the first polyurethane layer sprayed thereon is vacuum dried to obtain a polyurethane matrix layer firmly attached to the substrate;

[0023] S4, spraying silane coupling agent on the surface of the polyurethane matrix layer;

[0024] S5, performing alkali washing treatment on the nano-property enhanced powder to hydroxylate the surface, and drying to obtain hydroxylated nano-powder;

[0025] S6, spraying the hydroxylated nano-powder to the surface of the polyurethane matrix layer treated in S4 to form a powder enhanced layer;

[0026] S7, spraying waterborne polyurethane solution on the surface of the powder enhanced layer again to form a cover layer, and covering the powder enhanced layer inside;

[0027] S8, vacuum drying the component after spraying to obtain a composite coating with a three-layer structure of "polyurethane matrix layer-powder enhanced layer-polyurethane cover layer".

[0028] Further, in the above method for preparing a multi-system powder enhanced thermal protection and vibration damping coating, the thin-walled component includes one of a fiber reinforced resin matrix composite thin-walled component, a metal alloy thin-walled component, or a resin matrix fabric thin-walled component.

[0029] Further, in the above method for preparing a multi-system powder enhanced thermal protection and vibration damping coating, the nano-property enhanced powder is a nano-ceramic powder or a nano-ceramic-based hybrid powder, the surface of which can be hydroxylated; the nano-ceramic powder is preferably nano-α-Al2O3 powder, and the nano-ceramic-based hybrid powder is preferably a mixture of nano-α-Al2O3 powder and nano-Y2O3 powder.

[0030] Further, in the above method for preparing a multi-system powder enhanced thermal protection and vibration damping coating, in S1 and S4, the silane coupling agent is selected from at least one of zirconium aluminate coupling agent and epoxy silane coupling agent.

[0031] Further, in the above method for preparing a multi-system powder enhanced thermal protection and vibration damping coating, in S2 and S7, the waterborne polyurethane solution is selected from at least one of low VOC waterborne polyurethane, waterborne touch oil resin, and Syntegra YF4000 PUD.

[0032] Further, in the above method for preparing a multi-system powder enhanced thermal protection and vibration damping coating, in S3 and S8, the solution used for alkali washing treatment is NaOH aqueous solution; the conditions for vacuum drying are temperature of 30-80°C, vacuum degree of -0.1 MPa, and time of not less than 24 hours.

[0033] Further, in the above method for preparing a multi-system powder enhanced thermal protection and vibration damping coating, the method further includes step S9: repeating the operations of S4 to S8 at least once to construct a gradient composite coating structure with multiple powder enhanced layers.

[0034] The application also discloses a multi-system powder-reinforced thermal protection and vibration reduction coating prepared by the preparation method.

[0035] A polyurethane matrix layer chemically bonded with the surface of the thin-walled component through a silane coupling agent;

[0036] A powder-reinforced layer chemically bonded with the polyurethane matrix layer through the silane coupling agent and composed of hydroxylated nano-powder;

[0037] A polyurethane covering layer combined with the surface of the powder-reinforced layer and covering the powder-reinforced layer.

[0038] The application has the following advantages and beneficial effects:

[0039] 1. In the preparation method, the thermal protection effect is mainly provided by the nano-property-reinforced powder with high temperature resistance, which has good thermal protection effect and low thermal conductivity. In the application, the nano-property-reinforced powder is arranged in the middle layer of the coating, effectively solving the adhesion problem of the nano-property-reinforced powder.

[0040] 2. In the preparation method, the polyurethane matrix layer is combined with the structural component layer, the polyurethane matrix layer is combined with the powder-reinforced layer, and the powder-reinforced layer is combined with the covering layer through a coupling reaction, forming a multi-coating system, and effectively solving the interface combination problem between the layers of the coating and between the coating and the surface of the structural component, and improving the interface bonding force.

[0041] 3. The preparation method has simple process, strong universality and easily available raw materials, and can prepare a high-temperature-resistant thermal protection coating on the surface of the material without high-energy-consumption steps such as high-temperature sintering. The high-temperature-resistant thermal protection coating can utilize the thermal protection function and low thermal conductivity of the powder-reinforced layer in the heat protection process, thereby significantly reducing the ablation rate and mass loss rate of the material. The areal density and thickness of the coating can be flexibly designed and adjusted according to needs, and the application is suitable for large-scale industrial application.

[0042] 4. The multi-system powder-reinforced thermal protection and vibration reduction coating has high damping effect, can effectively realize the vibration reduction effect of the structural component, and will not significantly increase the mass of the structural component. The vibration reduction performance is mainly caused by the energy dissipation caused by the inter-particle friction of the powder-reinforced layer in the deformation process, and the energy dissipation caused by the viscoelastic deformation of the matrix layer also plays an important role. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1Figure 1 is a model diagram of the surface coating of the T700 carbon fiber sheet sample of Example 1, wherein 1 is the powder reinforced layer; 2 is the polyurethane covering layer; 3 is the surface of the T700 carbon fiber sheet sample; 4 is the silane coupling reaction layer; 5 is the polyurethane matrix layer;

[0044] Figure 2 Figure 2 is a sample diagram, wherein (a) is a T700 carbon fiber sheet sample without coating; (b) is a T700 carbon fiber sheet sample coated with a double-layer polyurethane coating of Comparative Example 1; (c) is a T700 carbon fiber sheet sample coated with a multi-system powder-reinforced damping thermal protection coating of Example 1; (d) is a T700 carbon fiber sheet sample coated with a multi-system powder-reinforced damping thermal protection coating of Example 2;

[0045] Figure 3 Figure 3 is a graph of the temperature rise curves of the T700 carbon fiber sheet samples coated with the coatings of Examples 1, 2 and Comparative Example 1, and the T700 carbon fiber sheet sample without coating, under constant temperature;

[0046] Figure 4 Figure 4 is a comparison diagram of infrared thermal imaging of the T700 carbon fiber sheet samples coated with the coatings of Examples 1, 2 and Comparative Example 1, and the T700 carbon fiber sheet sample without coating, under constant temperature; wherein (a) is a comparison diagram of infrared thermal imaging after 30 minutes after the start of the test; (b) is a comparison diagram of infrared thermal imaging after 31 minutes and 30 seconds after the start of the test; (c) is a comparison diagram of infrared thermal imaging after 32 minutes after the start of the test; (d) is a comparison diagram of infrared thermal imaging after 32 minutes and 30 seconds after the start of the test; (e) is a comparison diagram of infrared thermal imaging after 33 minutes and 30 seconds after the start of the test; (f) is a comparison diagram of infrared thermal imaging after 34 minutes after the start of the test; (g) is a comparison diagram of infrared thermal imaging after 34 minutes and 30 seconds after the start of the test; (h) is a comparison diagram of infrared thermal imaging after 35 minutes after the start of the test; in the figure, P1 is the infrared thermal imaging diagram of the T700 carbon fiber sheet sample without coating, P2 is the infrared thermal imaging diagram of the T700 carbon fiber sheet sample coated with the multi-system powder-reinforced damping thermal protection coating of Example 1, P3 is the infrared thermal imaging diagram of the T700 carbon fiber sheet sample coated with the double-layer polyurethane coating of Comparative Example 1, and P4 is the infrared thermal imaging diagram of the T700 carbon fiber sheet sample coated with the multi-system powder-reinforced damping thermal protection coating of Example 2;

[0047] Figure 5 Figure 5 is a three-dimensional surface topography diagram of the T700 carbon fiber sheet sample coated with the coating of Example 1;

[0048] Figure 6 Figure 6 is a two-dimensional super-depth microscopic diagram of the T700 carbon fiber sheet sample coated with the coating of Example 1;

[0049] Figure 7Comparison of time-domain response curves of T700 carbon fiber sheet samples coated with the coating of Example 1 and T700 carbon fiber sheet samples without coating under random vibration;

[0050] Figure 8 Comparison of frequency-domain response curves of T700 carbon fiber sheet samples coated with the coating of Example 1 and T700 carbon fiber sheet samples without coating under random vibration;

[0051] Figure 9 Comparison of power spectral density curves of T700 carbon fiber sheet samples coated with the coating of Example 1 and T700 carbon fiber sheet samples without coating under random vibration;

[0052] Figure 10 Cross-sectional ultra-depth microscopic image of T700 carbon fiber sheet sample coated with the coating of Example 3. DETAILED DESCRIPTION

[0053] The specific embodiments of the present application will be further described in conjunction with the accompanying drawings and examples. It should be understood that the embodiments described herein are only used to explain the present application and are not intended to limit the present application.

[0054] The purity of all raw materials of the present application is not particularly limited, and the present application preferably uses industrial pure or conventional purity used in the art.

[0055] The device used in the present application is not particularly limited and uses the device commonly used in the art.

[0056] In the following examples, the aqueous polyurethane solution is selected from low VOC aqueous polyurethane, specifically F0413 type aqueous polyurethane from Shenzhen Jitian Chemical Co., Ltd.

[0057] The spraying sample used is T700 carbon fiber sheet, and the interlayer adhesive matrix is epoxy resin, which is provided by Weihai Guangwei Composite Material Co., Ltd.

[0058] The epoxy silane coupling agent is used as the coupling reaction reagent, specifically 3-glycidyloxypropyl trimethoxysilane provided by Aladdin Biochemical Technology Co., Ltd.

[0059] The nano performance enhancing powder is selected from nano type Al2O3 powder and Y2O3 powder, and the nano type Al2O3 powder and Y2O3 powder used are provided by Aladdin Biochemical Technology Co., Ltd.

[0060] The NaOH solution is used as the main solution for alkaline washing, and the NaOH solution used is provided by Aladdin Biochemical Technology Co., Ltd.

[0061] Example 1

[0062] The preparation method of the multi-system powder reinforced thermal protection and damping coating of the embodiment comprises the following steps:

[0063] S1, uniformly spray silane coupling agent on the surface of T700 carbon fiber sheet, so that it is coupled with the surface resin matrix.

[0064] S2, uniformly coat the treated surface with water-based polyurethane. Through interfacial coupling reaction, polyurethane forms a layer of adhesive matrix layer, firmly adheres to the substrate, and enhances the surface adhesion strength.

[0065] S3, place the sprayed sample in a vacuum drying oven, with a temperature of 30°C and a vacuum degree of -0.1 Mpa, and dry for 24 hours to obtain a sample with a polyurethane matrix layer.

[0066] S4, treat the surface of the T700 carbon fiber sheet sample with a polyurethane matrix layer with silane coupling agent to enhance interfacial compatibility.

[0067] S5, place nano-Al2O3 powder in a beaker and wash it with NaOH solution to introduce hydroxyl groups on its surface.

[0068] S6, filter out the NaOH solution using filter paper, and then dry the solid precipitate on the filter paper at room temperature and normal pressure to obtain nano α-type Al2O3 powder with surface hydroxylation.

[0069] S7, spray the nano α-type Al2O3 powder with surface hydroxylation on the surface of the T700 carbon fiber sheet sample with a polyurethane matrix layer treated with silane coupling agent using a sandblasting gun to form a powder reinforced layer.

[0070] S8, coat a layer of water-based polyurethane, i.e. polyurethane cover layer, on the surface of the powder reinforced layer to wrap the nano α-type Al2O3 powder reinforced layer.

[0071] S9, place the coated T700 carbon fiber sheet sample after all spraying is completed in a vacuum drying oven, with a temperature of 30°C and a vacuum degree of -0.1 Mpa, and dry for 24 hours to obtain a T700 carbon fiber sheet sample with a composite coating of "polyurethane matrix layer-powder reinforced layer-polyurethane cover layer" structure.

[0072] The model diagram of the composite coating with "polyurethane matrix layer-powder reinforced layer-polyurethane cover layer" structure is shown in Figure 1 , which includes polyurethane matrix layer 5, powder reinforced layer 1 and polyurethane cover layer 2 on the surface 3 of T700 carbon fiber sheet sample, wherein the surface 3 of T700 carbon fiber sheet sample and the surface of polyurethane matrix layer 5 are silane coupling reaction layers 4 with coupling functional groups.

[0073] Comparative Example 1

[0074] The comparative example provides a method for preparing a T700 carbon fiber sheet sample coated with a double-layer polyurethane coating, specifically comprising the following steps:

[0075] S1, uniformly spray a silane coupling agent on the surface of the T700 carbon fiber sheet, so that it is coupled with the resin matrix on the surface.

[0076] S2, uniformly coat the treated surface with water-based polyurethane. Through interfacial coupling reaction, the polyurethane forms a layer of adhesive matrix layer, firmly adheres to the substrate, and enhances the surface adhesion strength.

[0077] S3, place the sprayed sample in a vacuum drying oven, with a temperature of 30°C and a vacuum degree of -0.1 Mpa, and dry for 24 hours to obtain a sample with a polyurethane collective layer.

[0078] S4, continue to treat the surface of the sample with a silane coupling agent.

[0079] S5, coat a layer of water-based polyurethane on the surface of the sample.

[0080] S6, place the coated T700 carbon fiber sheet sample after spraying in a vacuum drying oven, with a temperature of 30°C and a vacuum degree of -0.1 Mpa, and dry for 24 hours to obtain a T700 carbon fiber sheet sample coated with a double-layer polyurethane coating on the surface.

[0081] Example 2

[0082] The preparation method of the multi-system powder reinforced thermal protection and vibration damping coating of the present example comprises the following steps:

[0083] S1, uniformly spray a silane coupling agent on the surface of the T700 carbon fiber sheet, so that it is coupled with the resin matrix on the surface.

[0084] S2, uniformly coat the treated surface with water-based polyurethane. Through interfacial coupling reaction, the polyurethane forms a layer of adhesive matrix layer, firmly adheres to the substrate, and enhances the surface adhesion strength.

[0085] S3, place the sprayed sample in a vacuum drying oven, with a temperature of 30°C and a vacuum degree of -0.1 Mpa, and dry for 24 hours to obtain a sample with a polyurethane collective layer.

[0086] S4, treat the surface of the T700 carbon fiber sheet sample with a polyurethane matrix with a silane coupling agent to enhance the interfacial compatibility.

[0087] S5, the nano-Al2O3 powder and the nano-Y2O3 powder are placed in a beaker in a ratio of 10:1, and an alkali washing is performed using a NaOH solution to introduce hydroxyl groups on the surfaces thereof.

[0088] S6, the NaOH solution is filtered off using filter paper, and the solid precipitate on the filter paper is left to stand, and then dried at normal temperature and pressure to obtain a mixed nano-performance enhancing powder of the nano-a-type Al2O3 powder and the nano-Y2O3 powder with hydroxyl groups on the surfaces thereof.

[0089] S7, the hydroxylated mixed nano-performance enhancing powder is sprayed on the surface of a T700 carbon fiber sheet sample having a polyurethane matrix that has been treated with a silane coupling agent using a sandblasting gun to form a powder reinforcing layer.

[0090] S8, a layer of water-based polyurethane, i.e., a polyurethane covering layer, is coated on the surface of the powder reinforcing layer to wrap the mixed powder reinforcing layer.

[0091] S9, the coated T700 carbon fiber sheet sample after the entire spraying process is placed in a vacuum drying oven, the temperature is 30°C, the vacuum degree is -0.1 Mpa, and drying is performed for 24 hours. A T700 carbon fiber sheet sample having a composite coating of a "polyurethane matrix layer-powder reinforcing layer-polyurethane covering layer" structure is obtained.

[0092] Example 3

[0093] The preparation method of the multi-system powder-reinforced thermal protection and vibration damping coating of this example includes the following steps:

[0094] S1, a silane coupling agent is uniformly sprayed on the surface of a T700 carbon fiber sheet to enable a coupling reaction with the resin matrix on the surface.

[0095] S2, a water-based polyurethane is uniformly coated on the treated surface. Through an interfacial coupling reaction, the polyurethane forms a cohesive matrix layer that is firmly attached to the substrate and enhances the surface adhesion strength thereof.

[0096] S3, the sprayed sample is placed in a vacuum drying oven, the temperature is 80°C, the vacuum degree is -0.1 Mpa, and drying is performed for 24 hours to obtain a sample having a polyurethane matrix layer.

[0097] S4, the surface of a T700 carbon fiber sheet sample having a polyurethane matrix layer is treated with a silane coupling agent to enhance the interfacial compatibility.

[0098] S5, the nano-Al2O3 powder is placed in a beaker, and an alkali washing is performed using a NaOH solution to introduce hydroxyl groups on the surfaces thereof.

[0099] S6, filter out the NaOH solution using filter paper, let the solid precipitate on the filter paper stand, and then dry at normal temperature and pressure to obtain the surface-hydroxylated nano α-Al2O3 powder.

[0100] S7, spray the surface-hydroxylated nano α-Al2O3 powder on the surface of the T700 carbon fiber sheet sample with a silane coupling agent treated polyurethane matrix layer using a sandblasting gun to form a powder reinforced layer.

[0101] S8, coat the surface of the powder reinforced layer with a layer of water-based polyurethane, i.e., a polyurethane cover layer, to wrap the nano α-Al2O3 powder reinforced layer.

[0102] S9, place the coated T700 carbon fiber sheet sample after all spraying is completed in a vacuum drying oven at a temperature of 80°C and a vacuum degree of -0.1 Mpa for drying for 24 hours.

[0103] S10, repeat the deposition and coating cycle 5 times to prepare a T700 carbon fiber sheet sample with a composite coating of 5-layer structure.

[0104] Figure 10 The cross-sectional ultra-depth microscopic image of the sample prepared in Example 3 shows that the adhesion between the layers is good and there is no obvious delamination. Figure 10 It can be seen that the coating has little effect on the thickness and surface macroscopic roughness.

[0105] Figure 2 The sample images show the T700 carbon fiber sheet sample without coating and the T700 carbon fiber sheet samples coated with the coatings of Examples 1 and 2 and Comparative Example 1, wherein Figure 2 a is the T700 carbon fiber sample without coating, Figure 2 b is the T700 carbon fiber sample coated with Comparative Example 1, Figure 2 c is the T700 carbon fiber sample coated with Example 1, Figure 2 d is the T700 carbon fiber sample coated with Example 2, and it can be seen that the coating has little effect on the thickness and surface macroscopic roughness.

[0106] Figure 3 The temperature rising curve graphs of the T700 carbon fiber sheet samples coated with the coatings of Examples 1 and 2 and Comparative Example 1 and the T700 carbon fiber sheet without coating at constant temperature show that Figure 3It can be seen that the sample coated with Example 2 is heated up most slowly, followed by the sample coated with Example 1, which proves that the nano-performance enhanced powder contributes to the thermal insulation performance of the coating. The sample coated with Comparative Example 1 has a similar temperature rising curve compared with the uncoated sample, which proves that the pure polyurethane matrix does not have thermal insulation capacity. The temperature of the sample of Example 2 proposed by the present application is reduced by 19.8% at 200℃ for 60 minutes, which proves that the multi-system powder enhanced vibration damping and thermal protection coating proposed by the present application has good thermal insulation performance.

[0107] The samples of Example 1, 2 and Comparative Example 1 were subjected to thermal insulation performance test, surface morphology test and vibration damping performance test.

[0108] Thermal insulation performance test: the test equipment includes a heating table and an infrared thermal imager. The heating table is adjusted to a constant temperature, and the infrared thermal imager is used to take pictures of the temperature rising process of different samples to evaluate the thermal insulation performance of the coating. The specific test results are shown in Figure 4 , Figure 5 .

[0109] As can be seen from Figure 4 , the samples coated with Example 1 and 2 have darker colors in the infrared images under the thermal radiation of 200℃, which proves that their temperatures and heat penetration efficiencies are lower. The infrared images of Comparative Example 1 and the uncoated sample are lighter in color and have highlights, which proves that their temperatures and heat penetration efficiencies are higher. Through comparison, it is indirectly proved that the coating proposed by the present application has good thermal protection effect.

[0110] From the three-dimensional surface morphology of Figure 5 , it can be seen that the surface of the coating has many irregular protrusions with a maximum height of 230μm. Such protrusions can effectively enhance the mechanical anchoring effect of the coating, thereby improving the adhesion and being beneficial to improving the anti-peeling performance of the coating in the impact and thermal cycling environment. The surface roughness of the coating meets the requirements of most engineering projects.

[0111] Surface morphology test: the test equipment includes an ultra-deep microscope, a workstation and corresponding software. The surface morphology of the coating is scanned by the ultra-deep microscope to evaluate the surface roughness of the coating. The specific test results are shown in Figure 6 .

[0112] From the two-dimensional ultra-deep microscopic images of Figure 6 , it can be seen that the treated nano-powder has good compatibility with the polyurethane matrix without obvious pores or other defects. The nano-particles are uniformly and fully dispersed in the matrix without obvious agglomeration, which is very important for improving the comprehensive performance of the coating.

[0113] Vibration reduction performance test: the test equipment includes an electromagnetic vibration table, an LMS data acquisition instrument, and an acceleration sensor. The vibration reduction contribution of the coating is evaluated by comparing the vibration response of the sample coated with the coating and the sample without the coating under random excitation. The specific test results are shown in Figure 7 , Figure 8 and Figure 9 . As can be seen from Figure 7 , the time-domain vibration response of the T700 carbon fiber sheet sample coated with the coating of embodiment 1 under random vibration is lower than that of the uncoated sample, proving the vibration reduction performance of the multi-system powder enhanced vibration reduction thermal protection coating proposed in the present application. As can be seen from Figure 8 , the vibration response peak of the T700 carbon fiber sheet sample coated with the coating of embodiment 1 is 34.8% lower than that of the uncoated sample, proving the vibration reduction performance of the multi-system powder enhanced coating proposed in the present application. In addition, the peak frequency is smaller than that of the uncoated sample, which is due to the mass contribution of the multi-system powder enhanced vibration reduction thermal protection coating. As can be seen from Figure 9 , the vibration response peak of the T700 carbon fiber sheet sample coated with the coating of embodiment 1 is 41.2% lower than that of the uncoated sample, proving that the multi-system powder enhanced vibration reduction thermal protection coating proposed in the present application has excellent energy dissipation capacity.

Claims

1. A method for preparing a multi-system powder-reinforced thermal protective and vibration-damping coating, characterized in that, Includes the following steps: S1. Clean the surface of the thin-walled component and pre-treat it with silane coupling agent to introduce coupling functional groups. S2. Spray an aqueous polyurethane solution onto the surface of the pretreated thin-walled component to form the first polyurethane layer; S3. Vacuum dry the thin-walled component coated with the first polyurethane layer to obtain a polyurethane matrix layer that is firmly attached to the substrate. S4. Spray a silane coupling agent onto the surface of the polyurethane matrix layer; S5. The nano-performance enhancement powder is subjected to alkaline washing to hydroxylate its surface, and then dried to obtain hydroxylated nano-powder. S6. Spray the hydroxylated nanopowder onto the surface of the polyurethane matrix layer treated in S4 to form a powder reinforcement layer; S7. Spray an aqueous polyurethane solution onto the surface of the powder reinforcement layer again to form a covering layer that encapsulates the powder reinforcement layer. S8. Vacuum dry the sprayed components to obtain a composite coating with a structure of "polyurethane matrix layer - powder reinforcement layer - polyurethane cover layer". In S5, the nano-performance-enhancing powder is a surface-hydroxylable nano-ceramic powder or a nano-ceramic-based hybrid powder, wherein the nano-ceramic-based hybrid powder is selected as a mixture of nano-α-Al2O3 powder and nano-Y2O3 powder; The alkaline washing treatment described in S5 uses an aqueous solution of NaOH. In S3 and S8, the vacuum drying conditions are: temperature 30℃-80℃, vacuum degree -0.1MPa, and time not less than 24 hours; The method further includes step S9: repeating operations S4 to S8 at least once to construct a gradient composite coating structure with multiple powder reinforcement layers.

2. The method for preparing a multi-system powder-reinforced thermal protective and vibration-damping coating according to claim 1, characterized in that, The thin-walled component includes one of fiber-reinforced resin-based composite thin-walled components, metal alloy thin-walled components, or resin-based fabric thin-walled components.

3. The method for preparing a multi-system powder-reinforced thermal protective and vibration-damping coating according to claim 1, characterized in that, In S1 and S4, the silane coupling agent is selected from at least one of zirconium aluminate coupling agents and epoxy silane coupling agents.

4. The method for preparing a multi-system powder-reinforced thermal protective and vibration-damping coating according to claim 1, characterized in that, In S2 and S7, the aqueous polyurethane solution is selected from at least one of the following: F0413 type aqueous polyurethane from Shenzhen Yoshida Chemical Co., Ltd., aqueous tactile oil resin, and Syntegra YF4000 PUD.

5. A multi-system powder-reinforced vibration-damping thermal protective coating prepared by the preparation method according to any one of claims 1-4, characterized in that, The coating adheres to the surface of the thin-walled component and comprises, from the inside out: A polyurethane matrix layer chemically bonded to the surface of a thin-walled component via a silane coupling agent; A powder reinforcement layer composed of hydroxylated nanoparticles and chemically bonded to the polyurethane matrix layer by a silane coupling agent; A polyurethane overlay layer that is bonded to and covers the surface of the powder reinforcement layer.

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