High-strength rocket launching pad heat-proof coating and preparation method thereof

Abstract

The invention discloses a high-strength rocket launching pad heat-proof coating and a preparation method thereof, belongs to the technical field of material preparation, and solves the problems that a heat-proof coating in the prior art is insufficient in cracking resistance and cannot resist crack initiation and expansion under extreme thermal stress; and the coating and the base material or the interior of the coating are layered. The high-strength rocket launching pad heat-proof coating provided by the invention is sprayed on a metal base material, and the heat-proof coating structurally comprises an organic layer and an inorganic layer in sequence from inside to outside; the base material of the organic layer comprises a resin-based heat-proof coating FRC-100; the base material of the inorganic layer comprises a water-hardened inorganic fireproof coating FRC-410, high-silica glass high-temperature-resistant inorganic long fibers are added in the inorganic layer, and an upper steel wire mesh and a lower steel wire mesh are embedded in the inorganic layer; and a KH-560 silane coupling agent layer is sprayed between the organic layer and the inorganic layer. Through the progressive design of the three elements of interface bonding, microcosmic enhancement and macroscopic stabilization, the crack resistance and the self stability of the heat-proof coating are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of materials preparation technology, specifically to a high-strength heat-resistant coating for rocket launch pads and its preparation method. Background Technology

[0002] Existing patent CN116254033A discloses a flexible low-density ablation heat-resistant coating and its preparation method. The filler in the heat-resistant coating is a particle or short fiber (only 2-3 mm in length). Its formulation product has insufficient crack resistance and cannot resist the initiation and propagation of cracks under extreme thermal stress. The lack of sufficient mechanical fixation measures at the interface between the heat-resistant coating and the metal substrate can easily lead to delamination of the coating-substrate or the coating itself due to the accumulation of internal stress, thus compromising the stability of the interface bond.

[0003] When heat-resistant coatings are constrained in deformation, they generate internal stress. When this internal stress exceeds the coating's tensile strength, microcracks gradually propagate and interconnect. Insufficient mechanical fixation between the coating and the metal substrate can lead to localized stress concentration in the structure, exacerbating internal stress and triggering crack propagation. Simultaneously, insufficient mechanical fixation can cause relative slippage between the reinforcing steel and concrete, disrupting the coordinated deformation of the coating and the metal substrate. This relative slippage causes additional stress on the protective coating under load, further intensifying crack initiation and propagation. Ultimately, these cracks propagate and connect to form macroscopic cracks, eventually leading to rupture and eventual detachment under vibration. Summary of the Invention

[0004] This invention addresses the shortcomings and deficiencies of existing technologies by providing a high-strength rocket launch pad heat-resistant coating and its preparation method. This coating utilizes a coupling agent to provide an effective bonding foundation for the coating interface, incorporates long fibers to enhance the coating's microscopic crack resistance, and adds steel wire mesh to improve the overall vibration resistance. Through a three-element progressive design of "interfacial bonding (coupling agent) → microscopic reinforcement (long fibers) → macroscopic stability (steel wire mesh)," the crack resistance and stability of the heat-resistant coating are significantly increased.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: The high-strength rocket launch pad heat-resistant coating provided by the present invention is sprayed on a metal substrate, and its heat-resistant coating structure consists of an organic layer and an inorganic layer from the inside to the outside. The organic layer substrate material includes resin-based heat-resistant coating FRC-100; the organic layer spraying thickness is 1~5mm; The inorganic layer matrix material includes water-hardening inorganic refractory coating FRC-410, and high-silica glass high-temperature resistant inorganic long fibers with a length of 20-30mm are added to the inorganic layer at a dosage of 0.2%-0.9%; two layers of steel wire mesh are embedded in the inorganic layer; the total thickness of the inorganic layer is 10~30mm. A KH-560 silane coupling agent layer is sprayed between the organic layer and the inorganic layer.

[0006] Preferably, the resin-based heat-resistant coating FRC-100 includes FRC-100A and FRC-100B, wherein the mass ratio of FRC-100A to FRC-100B is 1.22:1; The inorganic matrix material includes water-curing inorganic refractory coating FRC-410, in which the water:cement mass ratio is 12~13:100.

[0007] Preferably, the wire diameter of the wire mesh is 0.1~3mm, the mesh size is 2~8mm, and the material is 304 stainless steel; The concentration of KH-560 silane coupling agent is 0.5%-5%, and the thickness is 5-10μm.

[0008] The preparation method of the above-mentioned high-strength rocket launch pad heat-resistant coating includes the following steps: spraying an organic layer, coupling agent treatment, and spraying an inorganic layer; During the spraying of the inorganic layer, two layers of steel wire mesh are embedded within the inorganic layer. The specific steps for laying the steel wire mesh are as follows: Before laying the wire mesh, spray a silane coupling agent onto the surface of the organic layer FRC100 coating. After the anhydrous ethanol in the coupling agent solution has completely evaporated, apply a 2-3 mm thick preliminary inorganic layer evenly to the interface. Then, before the preliminary inorganic layer cures, lay the first layer of wire mesh. Next, spray an intermediate inorganic layer evenly onto the preliminary layer of wire mesh until the total thickness of the inorganic layer reaches 80% of the final thickness. Before the coating cures, lay the second layer of wire mesh. Finally, the construction is completed when the inorganic coating thickness reaches 100%. The inorganic layer thickness is 10~30mm.

[0009] Preferably, the wire mesh pretreatment process is also included before the wire mesh is laid. The wire mesh needs to be treated with "sandblasting roughening and degreasing" before use.

[0010] Preferably, the process includes matrix premixing and fiber dispersion steps before spraying the organic layer. The matrix premixing step includes premixing of organic layer matrix materials and premixing of inorganic layer matrix materials; The organic layer matrix material includes resin-based heat-resistant coating FRC-100, and the volume content of solid matter in the organic layer is 88%. The premixing operation of the organic layer matrix material is as follows: resin-based heat-resistant coating FRC-100: FRC-100A and FRC-100B are mixed evenly by mechanical stirring at room temperature (25℃) for 20 minutes. The inorganic layer matrix material includes water-curing inorganic refractory coating FRC-410, and the volume content of solid matter in the inorganic layer is 100%. The specific operation of the inorganic layer matrix material premixing is as follows: water is added to the coating in three equal parts at room temperature (25℃) and mechanically stirred, with each operation time being 3~5 minutes and the total operation time being 10~15 minutes.

[0011] Preferably, the fiber dispersion process is as follows: high-silica glass high-temperature resistant inorganic long fibers with a length of 20-30mm are added to the inorganic coating; the long fiber reinforcement is added to the inorganic coating by using the "pre-dispersion-high-speed stirring dispersion method" to ensure that the long fiber reinforcement is uniformly dispersed. First, the long fiber reinforcement and the dry powder component of the inorganic coating are manually premixed in a bag to allow the fibers to be initially encapsulated and separated by the powder. Then, the mixed dry material is slowly added to the liquid component and stirred evenly using a high-power (≥10KW) mixer to ensure uniform fiber dispersion.

[0012] Preferably, the coupling agent is applied by low-pressure airless spraying, with the thickness controlled at 5-10 μm.

[0013] Preferably, static curing is also included.

[0014] This invention provides a high-strength heat-resistant coating for rocket launch pads and its preparation method. It has the following beneficial effects: (1) The high-strength rocket launch pad heat-resistant coating and its preparation method of the present invention, based on the prior art, use coupling agent to provide an effective bonding basis for the coating interface, add long fibers to the formula to improve the microscopic crack resistance of the coating, and add steel wire mesh to improve the overall vibration resistance of the coating. Through the three-element progressive design of “interface bonding (coupling agent) → microscopic reinforcement (long fiber) → macroscopic stability (steel wire mesh)”, the crack resistance and self-stability of the heat-resistant coating are significantly increased.

[0015] (2) The high-strength rocket launch pad heat-resistant coating and its preparation method of the present invention use long fibers to form a "bridging structure" when microcracks appear in the fireproof coating, which prevents the cracks from expanding further. This effect can effectively disperse stress and inhibit the cracks from continuing to develop.

[0016] In addition, when adding fibers to the inorganic layer formulation, the "pre-dispersion-high-speed stirring dispersion method" is used to ensure that the fibers are evenly dispersed, so that there is a large friction between the long fibers and the fireproof coating matrix. When the cracks expand, the fibers are gradually pulled out. During this process, the friction between the fibers and the matrix can effectively delay the expansion of the cracks. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the high-strength rocket launch pad heat-resistant coating in Embodiment 1 of the present invention. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Unless otherwise specified, the following materials are all commercially available products. Example 1

[0019] Please see Figure 1 The high-strength rocket launch pad heat-resistant coating provided by the present invention is sprayed on a metal substrate, and its heat-resistant coating structure consists of an organic layer and an inorganic layer from the inside to the outside. The organic layer matrix material includes resin-based heat-resistant coating FRC-100; the organic layer spraying thickness is 1~5mm; the resin-based heat-resistant coating FRC-100 includes FRC-100A and FRC-100B, wherein the mass ratio of FRC-100A to FRC-100B is 1.22:1; The inorganic layer matrix material includes water-curing inorganic refractory coating FRC-410, wherein the water:ash mass ratio is 12~13:100. High-silica glass high-temperature resistant inorganic long fibers with a length of 20-30mm are added to the inorganic layer at an addition rate of 0.2%-0.9%. The inorganic layer is embedded with two layers of steel wire mesh; the total thickness of the inorganic layer is 10~30mm; the diameter of the steel wire mesh is 0.1~3mm, the mesh size is 2~8mm, and the material is 304 stainless steel. A KH-560 silane coupling agent layer is sprayed between the organic layer and the inorganic layer. The concentration of KH-560 silane coupling agent is 0.5%-5%, and the thickness is 5-10μm.

[0020] Commercially available fire-retardant coatings with the grades FRC100 and FRC400 are as follows: 1. FRC100 Fire Retardant Coating: This product is a high-solids solvent-based two-component organic heat-resistant coating, FRC-100A and FRC-100B, mainly composed of special resins, solvents, hollow glass microspheres, and other fillers. It features low density, excellent heat insulation performance, outstanding adhesion, and good processability. It can cure at room temperature and is suitable for various substrates such as stainless steel, aluminum alloys, and composite materials. It can be directly sprayed without a primer to achieve good adhesion and has good compatibility with paints.

[0021] model FRC100 Density (g / cm3) 0.40~0.60 Thermal conductivity (W / mK) ≤0.10 Specific heat capacity (J / (g.℃)) ＞1.2 Tensile strength (MPa) ≥1.2 Tensile shear strength (MPa) ≥3.0 Temperature tolerance (°C) 1000 Applicable heat flow conditions <![CDATA[300KW / m 2 ]]> Application objects Heat protection (primer) for rocket launch pads, lifting arms, service arms, and missile silos. 2. FRC410 Fire-retardant Coating: This product is a water-based, three-component inorganic heat-resistant coating, mainly composed of inorganic resin and heat-resistant fillers. It features excellent heat resistance, high strength, and good toughness. It can be applied by brushing or scraping and has good compatibility with paints. Example 2

[0022] A method for preparing a high-strength heat-resistant coating for rocket launch pads includes the following steps: S1, Matrix premixing step, including organic layer matrix material premixing and inorganic layer matrix material premixing; S1.1 Organic Layer The organic layer matrix material includes resin-based heat-resistant coating FRC-100, and the volume content of solid matter in the organic layer is 88%. The premixing process of the organic layer matrix material is as follows: resin-based heat-resistant coating FRC-100: FRC-100A and FRC-100B are mixed evenly by mechanical stirring at room temperature (25℃) for 20 minutes. Construction method: Apply the prepared FRC-100 evenly to the surface to be coated using air spraying, with a coating thickness of 1-5 mm. Ensure all surfaces are clean, dry, and free of contaminants. Before coating, all surfaces should be assessed and treated according to ISO 8504:2000 standards to remove weld spatter, smooth weld seams and sharp edges. Oils and greases should be removed according to SSPC-SP1 solvent cleaning standards. After spraying, allow to cure at room temperature for 5-7 days.

[0023] S1.2 Inorganic Layer Preparation process: The inorganic layer matrix material includes water-curing inorganic refractory coating FRC-410, and the volume content of solid matter in the inorganic layer is 100%; the premixing operation of the inorganic layer matrix material is as follows: water is added to the coating in three equal parts at room temperature (25℃) and mechanically stirred, each operation time is 3~5 minutes, and the total operation time is 10~15 minutes.

[0024] Construction method: Apply the prepared FRC-410 evenly to the surface to be coated using a self-leveling, trowel-applied method. Ensure all surfaces are clean, dry, and free of contaminants. After spraying, allow to cure at room temperature (15~30℃) for 3~5 days.

[0025] S2. Long fiber reinforcement fiber dispersion process: The operation steps of the fiber dispersion process are as follows: Add high-silica glass high-temperature resistant inorganic long fibers with a length of 20mm~30mm to the inorganic coating; Fiber parameters: length 20mm~30mm. If it is too short, it cannot effectively inhibit crack propagation; if it is too long, it is easy to agglomerate and cause uneven dispersion.

[0026] The long fiber reinforcement is added to the inorganic coating by using a "pre-dispersion-high-speed stirring dispersion method" to ensure uniform dispersion of the long fiber reinforcement. First, manually premix the long fiber reinforcement and the dry powder component of the inorganic coating in a bag for 5 minutes to allow the fiber to be initially wrapped and separated by the powder, effectively preventing the fiber from self-aggregating and clumping; then slowly add the mixed dry material to the liquid component and use a high-power (≥10KW) mixer to stir evenly to ensure uniform fiber dispersion.

[0027] S3. Apply the organic layer using the construction method of S1.1 organic layer; S4. Interface coupling agent treatment: After the organic layer is sprayed in step S3, an interface coupling agent is sprayed to improve the interfacial bonding force.

[0028] Coupling agent type: KH-560 (epoxysilane) is selected as the silane coupling agent. Its hydrolyzed silanol groups can fully combine with the hydroxyl groups on the surface of the underlying coating, while evaporating some of the solvent.

[0029] Timing and Process of Addition: After sandblasting and cleaning, wipe the FRC100 coating surface clean with anhydrous ethanol; prepare a 0.5%~5% KH560 solution using KH560 silane coupling agent and anhydrous ethanol; apply using low-pressure airless spraying to ensure uniform coverage of the coating surface, with a coating thickness controlled at 5-10 μm; allow to stand at room temperature for 15-30 min after coating. If the coupling agent layer is too thin, it will not provide interfacial reinforcement; if it is too thick, unreacted components may remain at the interface, which is detrimental to the establishment of interfacial strength.

[0030] S5. Apply the inorganic layer using the construction method of S1.2. During the application of the inorganic layer, two layers of steel wire mesh are embedded within the inorganic layer. The steel wire mesh is embedded in the middle of the heat-resistant coating to prevent surface wear from exposing the steel wire mesh. The specific steps for laying the steel wire mesh are as follows: Before laying the wire mesh, a pretreatment process is also included. The wire mesh must be treated with "sandblasting roughening and degreasing" before use to prevent rusting during use.

[0031] Before laying the wire mesh, spray a silane coupling agent onto the surface of the organic layer FRC100 coating. After the anhydrous ethanol in the coupling agent solution has completely evaporated, apply a 2-3 mm thick preliminary inorganic layer evenly to the interface. Then, before the preliminary inorganic layer cures, lay the first layer of wire mesh. Next, spray an intermediate inorganic layer evenly onto the preliminary layer of wire mesh until the total thickness of the inorganic layer reaches 80% of the final thickness. Before the coating cures, lay the second layer of wire mesh. Finally, the construction is completed when the inorganic coating thickness reaches 100%. The thickness of the inorganic layer is 10-30 mm.

[0032] Wire mesh material: 304 stainless steel (resistant to high structural temperatures ≥800℃, corrosion resistant, preventing rust caused by the humid environment of the launch pad); Wire mesh specifications: wire diameter 0.1~3mm (if the wire diameter is too thin, the strength will be insufficient, and if it is too thick, the coating will easily crack), mesh size 2~8mm (if the mesh size is too large, the reinforcement range will be limited, and if it is too small, the coating slurry will have difficulty penetrating).

[0033] S6. Allow to cure.

[0034] Based on existing technologies, this invention uses coupling agents to provide an effective bonding foundation for the coating interface, adds long fibers to the formula to improve the microscopic crack resistance of the coating, and adds steel wire mesh to improve the overall vibration resistance of the coating. Through the three-element progressive design of "interfacial bonding (coupling agent) → microscopic reinforcement (long fibers) → macroscopic stability (steel wire mesh)," the crack resistance and self-stability of the heat-resistant coating are significantly increased. Example 3

[0035] The high-strength rocket launch pad heat-resistant coating was prepared using the method described in Example 2 above. The formulation parameters for the heat-resistant coating are as follows: In the organic layer matrix material resin-based heat-resistant coating FRC-100, the ratio of FRC100A:FRC100B is 1.22:1; The inorganic layer matrix material includes water-curing inorganic refractory coating FRC-410, wherein the water:ash mass ratio is 12:100. Furthermore, high-silica, high-temperature resistant inorganic long fibers with a length of 20mm-30mm are added to the inorganic layer at a dosage of 0.2%wt. The inorganic layer is embedded with two layers of steel wire mesh; the steel wire diameter is 0.1mm, the mesh size is 2mm, and the material is 304 stainless steel. A KH-560 silane coupling agent layer is sprayed between the organic layer and the inorganic layer, with a KH-560 silane coupling agent mass fraction of 0.5%.

[0036] The wire mesh is made of 304 stainless steel with a wire diameter of 0.1mm and a mesh size of 2mm.

[0037] Preparation process: The organic coating thickness is 2mm, the total thickness of the inorganic layer is 20mm, and the KH-560 silane coupling agent layer with a thickness of 5-10μm is sprayed between the organic layer and the inorganic layer. Example 4

[0038] The high-strength rocket launch pad heat-resistant coating was prepared using the method described in Example 2 above. The formulation parameters for the heat-resistant coating are as follows: In the organic layer matrix material resin-based heat-resistant coating FRC-100, the ratio of FRC100A:FRC100B is 1.22:1; The inorganic layer matrix material includes water-curing inorganic refractory coating FRC-410, wherein the water:ash mass ratio is 12:100. Furthermore, high-silica, high-temperature resistant inorganic long fibers with a length of 20mm-30mm are added to the inorganic layer at a dosage of 0.5%wt. The inorganic layer is embedded with two layers of steel wire mesh; the steel wire diameter is 0.1mm, the mesh size is 2mm, and the material is 304 stainless steel. A KH-560 silane coupling agent layer is sprayed between the organic layer and the inorganic layer. The mass fraction of KH-560 silane coupling agent is 3.0%.

[0039] The wire mesh is made of 304 stainless steel with a wire diameter of 1mm and a mesh size of 5mm.

[0040] Preparation process: The organic coating thickness is 2mm, the total thickness of the inorganic layer is 20mm, and the KH-560 silane coupling agent layer with a thickness of 5-10μm is sprayed between the organic layer and the inorganic layer. Example 5

[0041] The high-strength rocket launch pad heat-resistant coating was prepared using the method described in Example 2 above. The formulation parameters for the heat-resistant coating are as follows: In the organic layer matrix material resin-based heat-resistant coating FRC-100, the ratio of FRC100A:FRC100B is 1.22:1; The inorganic layer matrix material includes water-curing inorganic refractory coating FRC-410, wherein the water:ash mass ratio is 12:100. Furthermore, high-silica, high-temperature resistant inorganic long fibers with a length of 20mm-30mm are added to the inorganic layer at a dosage of 0.9%wt. The inorganic layer is embedded with two layers of steel wire mesh; the steel wire diameter is 0.1mm, the mesh size is 2mm, and the material is 304 stainless steel. A KH-560 silane coupling agent layer is sprayed between the organic layer and the inorganic layer, with a KH-560 silane coupling agent mass fraction of 4%.

[0042] The wire mesh is made of 304 stainless steel with a wire diameter of 3mm and a mesh size of 8mm.

[0043] Preparation process: The organic coating thickness is 2mm, the total thickness of the inorganic layer is 20mm, and the KH-560 silane coupling agent layer with a thickness of 5-10μm is sprayed between the organic layer and the inorganic layer.

[0044] Comparative Example 1 The high-strength rocket launch pad heat-resistant coating was prepared using the method described in Example 2 above. The formulation parameters for the heat-resistant coating are as follows: In the organic layer matrix material resin-based heat-resistant coating FRC-100, the ratio of FRC100A:FRC100B is 1.22:1; The inorganic layer matrix material includes water-curing inorganic refractory coating FRC-410, wherein the water:cement mass ratio is 12:100.

[0045] Furthermore, high-silica glass high-temperature resistant short fibers with a length of 2mm-3mm are added to the inorganic layer at a rate of 0.5%wt. The inorganic layer is embedded with two layers of steel wire mesh; the steel wire diameter is 0.1mm, the mesh size is 2mm, and the material is 304 stainless steel. A KH-560 silane coupling agent layer is sprayed between the organic layer and the inorganic layer. The KH-560 silane coupling agent has a mass fraction of 4% and a thickness of 5-10 μm.

[0046] The wire mesh is made of 304 stainless steel with a wire diameter of 3mm and a mesh size of 8mm.

[0047] Preparation process: The organic coating thickness is 2mm, the total thickness of the inorganic layer is 20mm, and the KH-560 silane coupling agent layer with a thickness of 5-10μm is sprayed between the organic layer and the inorganic layer.

[0048] Comparative Example 2 The method for preparing a high-strength rocket launch pad heat-resistant coating in Example 2 above differs in that no silane coupling agent layer is added between the organic and inorganic layers. The formulation parameters for preparing the heat-resistant coating are as follows: In the organic layer matrix material resin-based heat-resistant coating FRC-100, the ratio of FRC100A:FRC100B is 1.22:1; The inorganic layer matrix material includes water-curing inorganic refractory coating FRC-410, wherein the water:ash mass ratio is 12:100. Furthermore, high-silica, high-temperature resistant inorganic long fibers with a length of 20mm-30mm are added to the inorganic layer at a dosage of 0.9%wt. The inorganic layer is embedded with two layers of steel wire mesh; the steel wire diameter is 0.1mm, the mesh size is 2mm, and the material is 304 stainless steel. The wire mesh is made of 304 stainless steel with a wire diameter of 3mm and a mesh size of 8mm.

[0049] Preparation process: The organic coating thickness is 2mm, and the total thickness of the inorganic layer is 20mm.

[0050] Comparative Example 3 The method for preparing a high-strength rocket launch pad heat-resistant coating in Example 2 above differs in that steel wire mesh is not added to the inorganic layer sprayed in step S5. The formulation parameters for preparing the heat-resistant coating are as follows: In the organic layer matrix material resin-based heat-resistant coating FRC-100, the ratio of FRC100A:FRC100B is 1.22:1; The inorganic layer matrix material includes water-curing inorganic refractory coating FRC-410, wherein the water:ash mass ratio is 12:100. Furthermore, high-silica, high-temperature resistant inorganic long fibers with a length of 20mm-30mm are added to the inorganic layer at a dosage of 0.9%wt. A KH-560 silane coupling agent layer is sprayed between the organic layer and the inorganic layer. The KH-560 silane coupling agent has a mass fraction of 4% and a thickness of 5-10 μm.

[0051] Preparation process: The organic coating thickness is 2mm, the total thickness of the inorganic layer is 20mm, and the KH-560 silane coupling agent layer with a thickness of 5-10μm is sprayed between the organic layer and the inorganic layer.

[0052] Comparative Example 4 The high-strength rocket launch pad heat-resistant coating was prepared using the method described in Example 2 above. The formulation parameters for the heat-resistant coating are as follows: In the organic layer matrix material resin-based heat-resistant coating FRC-100, the ratio of FRC100A:FRC100B is 1.22:1; The inorganic layer matrix material includes water-curing inorganic refractory coating FRC-410, wherein the water:ash mass ratio is 12:100. Furthermore, alkali-free and medium-alkali glass fibers with a length of 20mm-30mm are added to the inorganic layer at a dosage of 0.9% wt. The inorganic layer is embedded with two layers of steel wire mesh; the steel wire diameter is 0.1mm, the mesh size is 2mm, and the material is 304 stainless steel. A KH-560 silane coupling agent layer is sprayed between the organic layer and the inorganic layer, with a KH-560 silane coupling agent mass fraction of 4%.

[0053] The wire mesh is made of 304 stainless steel with a wire diameter of 3mm and a mesh size of 8mm.

[0054] Preparation process: The organic coating thickness is 2mm, the total thickness of the inorganic layer is 20mm, and the KH-560 silane coupling agent layer with a thickness of 5-10μm is sprayed between the organic layer and the inorganic layer.

[0055] To verify whether the performance of the high-strength rocket launch pad heat-resistant coating prepared by this invention has been effectively improved after material and process improvements, a vibration test was conducted to draw conclusions based on intuitive test phenomena and data.

[0056] 1 Experimental Design 1.1 Sample Preparation The heat-resistant coatings prepared in Examples 3-4, Comparative Examples 1-3, and the heat-resistant coating layer prepared by the flexible low-density ablation heat-resistant coating and formulation process of the prior art patent CN116254033A were used as blank groups for the experiment.

[0057] 1.2 Vibration peel test method The sample was subjected to sinusoidal frequency sweep plus random vibration tests in the XYZ directions, and the tests were performed on them respectively under given conditions.

[0058] 2. Experimental Results The vibration test site photos and data clearly and intuitively show that: Sample Name Vibration peel test Compressive strength (MPa) Ablation rate (mm / s) Example 3 After 5 minutes of X-axis sinusoidal frequency sweep and X-axis random vibration, no cracks or peeling were observed in the coating on the sample surface. After 10 minutes of Y-axis sinusoidal frequency sweep, the coating surface remained unchanged. During 10 minutes of Y-axis random vibration, a small crack appeared on the coating surface at 177 s; the crack length extended at 214 s; a crack appeared at the top of the sample at 298 s; and at 341 s, part of the heat-resistant coating peeled off, indicating coating structural failure, and the test ended. 37.6 0.915 Example 4 After 5 minutes of X-axis sinusoidal frequency sweep and X-axis random vibration, no cracks or peeling were observed in the coating on the sample surface. After 10 minutes of Y-axis sinusoidal frequency sweep, the coating surface remained unchanged. During 10 minutes of Y-axis random vibration, a small crack appeared on the coating surface at 102 s; the crack length extended at 188 s; a crack appeared at the top of the sample at 270 s; and at 330 s, part of the heat-resistant coating peeled off, indicating coating structural failure, and the test ended. 37.3 MPa 0.922 Example 5 After 5 minutes of X-axis sinusoidal frequency sweep and X-axis random vibration, no cracks or peeling were observed in the coating on the sample surface. After 10 minutes of Y-axis sinusoidal frequency sweep, the coating surface remained unchanged. During 10 minutes of Y-axis random vibration, a small crack appeared on the coating surface at 130 s; the crack length extended at 192 s; a crack appeared at the top of the sample at 273 s; and at 311 s, part of the heat-resistant coating peeled off, indicating coating structural failure, and the test ended. 37.1 MPa 0.917 Comparative Example 1 After 5 minutes of X-axis sinusoidal frequency sweep and X-axis random vibration, no cracks or peeling occurred in the coating on the sample surface. During 10 minutes of Y-axis sinusoidal frequency sweep, a small crack appeared on the coating surface at 247 seconds, and the crack propagated at 391 seconds. During 10 minutes of Y-axis random vibration, the heat-resistant coating partially peeled off the sample surface at 54 seconds, indicating coating structural failure, and the test was terminated. 32.7 MPa 1.034 Comparative Example 2 After 5 minutes of X-axis sinusoidal frequency sweep and X-axis random vibration, no cracks or peeling were observed in the coating on the sample surface. After 10 minutes of Y-axis sinusoidal frequency sweep, the coating surface remained unchanged. During 10 minutes of Y-axis random vibration, a small crack appeared on the coating surface at 36 seconds; the crack length extended at 77 seconds; a crack appeared at the top of the sample at 145 seconds; and at 186 seconds, part of the heat-resistant coating peeled off, indicating coating structural failure, and the test ended. 31.6 MPa 0.926 Comparative Example 3 After 5 minutes of sinusoidal frequency sweep along the X-axis and random vibration along the X-axis, no cracks or peeling were observed in the coating on the sample surface. After 10 minutes of sinusoidal frequency sweep along the Y-axis, the coating surface remained unchanged. During 10 minutes of random vibration along the Y-axis, a small crack appeared at the coating interface at 73 seconds; the crack length extended at 159 seconds; and the heat-resistant coating interface separated at 184 seconds, indicating coating failure, and the test ended. 32.1 MPa 0.919 Comparative Example 4 After 5 minutes of X-axis sinusoidal frequency sweep and X-axis random vibration, no cracks or peeling were observed in the coating on the sample surface. After 10 minutes of Y-axis sinusoidal frequency sweep, the coating surface remained unchanged. During 10 minutes of Y-axis random vibration, a small crack appeared on the coating surface at 167 s; the crack length extended at 190 s; a crack appeared at the top of the sample at 226 s; and at 253 s, part of the heat-resistant coating peeled off, indicating coating structural failure, and the test ended. 32.4 MPa 1.210 No improvement to the blank group After 5 minutes of sinusoidal frequency sweep along the X-axis, no cracks or peeling occurred on the sample surface. During 5 minutes of random vibration along the X-axis, small debris began to fall off the sample around 120 seconds into the test. At 150 seconds, a small corner of the coating peeled off. By 290 seconds, the entire surface coating had peeled off, indicating coating structural failure, and the test ended. Subsequent sinusoidal frequency sweeps and random vibrations along the Y-axis were not performed. 28.2 MPa 1.255 The samples were subjected to rigorous testing conditions through vibration tests. Although cracks appeared in the surface coating of the experimental group samples after random vibration along the Y-axis, the structural stability of the heat-resistant coating of the samples in Examples 3-5 of this invention was significantly improved compared with the test data of the blank group. The samples also exhibited high compressive strength of 37.1 MPa-37.6 MPa and ablation rate of 0.915 mm / s. This further demonstrates that the high-strength rocket launch pad heat-resistant coating prepared by the synergistic effect of the preparation method and formula of this invention has a high level of heat insulation and vibration resistance in practical applications.

[0059] The core innovation of this invention lies in the "synergistic enhancement of three elements," which differs from the single improvement in existing technologies, and its effect is greater than the cumulative effect of a single improvement. Specific experimental data results are compared with those in the blank group and comparative examples of existing technologies, and the results are analyzed as follows: (1) In Examples 3-5 of the present invention, the synergistic effect of long fibers and coupling agents is used in the formulation. Compared with the experimental data results of the blank group of the prior art and Comparative Example 2 without coupling agent, the heat-resistant coatings prepared in Examples 3-5 of the present invention are not easy to peel off at the interface between the coating and the substrate.

[0060] Compared to the short fiber filler used in Comparative Example 1, Examples 3-5 of this invention combine long fibers (20mm~30mm) with a silane coupling agent. The coupling agent constructs a chemical bonding interface, while the long fibers provide a continuous tensile path. Together, they address the problem of "fiber reinforcement but weak interfacial bonding," thus improving the tensile strength of the coating. The concentration of the KH-560 silane coupling agent is 0.5%-5%, and the thickness is 5-10μm. The 20-30mm high-silica glass fibers exhibit superior performance compared to the alkali-free and medium-alkali glass fibers used in Comparative Example 4.

[0061] (2) In Examples 3-5 of the present invention, the improved formula and the addition of steel wire mesh are synergistic in terms of structural stability. In Comparative Example 3 and the blank group, no macroscopic structural reinforcement was introduced, and the coating vibration resistance relied solely on its own toughness. In contrast, the present invention embeds pretreated stainless steel wire mesh in the middle layer of the coating, which forms a "mechanical interlocking force + interface bonding force" with the coating slurry, which can disperse vibration stress, avoid local cracking and peeling, and significantly improve its mechanical properties.

[0062] (3) In Examples 3-5 of the present invention, the overall improved formula and process improvement achieve synergistic effect on overall performance: the three are strengthened by a multi-dimensional design of “interface bonding (coupling agent) → micro-reinforcement (long fiber) → macro-stabilization (steel wire mesh). The coupling agent provides an effective bonding basis for the fiber, the long fiber improves the micro-crack resistance of the coating, and the steel wire mesh ensures the overall vibration and impact resistance of the coating, which ultimately effectively reduces the coating peeling rate.

[0063] Based on the above experimental data, this invention, building upon existing technologies, utilizes coupling agents to provide an effective bonding foundation for the coating interface. The addition of long fibers to the formulation enhances the coating's microscopic crack resistance, while the inclusion of steel wire mesh improves the overall vibration resistance. Through a progressive three-element design—"interfacial bonding (coupling agent) → microscopic reinforcement (long fibers) → macroscopic stability (steel wire mesh)"—the crack resistance and inherent stability of the heat-resistant coating are significantly increased. Furthermore, through a synergistic design of "raw material performance optimization and structural enhancement," the long fibers and coupling agent work together to improve tensile strength, and the embedded steel wire mesh forms mechanical interlocking and interfacial bonding forces to disperse vibration stress. This multi-dimensional strengthening achieves a heat-resistant coating with superior vibration resistance and anti-detachment performance.

[0064] The above are merely embodiments of the present invention. For example, the concentration of the coupling agent KH-560 silane coupling agent is 0.5%-5%, and the thickness is 5-10μm; high silica glass fibers with a fiber size of 20-30mm can all realize the high-strength rocket launch pad heat-resistant coating and its preparation method of the present invention.

[0065] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high-strength heat-resistant coating for rocket launch pads, characterized in that, The heat-resistant coating is sprayed onto a metal substrate, and its structure, from the inside out, consists of an organic layer and an inorganic layer. The organic layer substrate material includes resin-based heat-resistant coating FRC-100; the organic layer coating thickness is 1~5mm. The inorganic layer matrix material includes water-hardening inorganic refractory coating FRC-410, and high-silica glass high-temperature resistant inorganic long fibers with a length of 20-30mm are added to the inorganic layer at a dosage of 0.2%-0.9%; the inorganic layer is embedded with upper and lower layers of steel wire mesh; the total thickness of the inorganic layer is 10-30mm. A KH-560 silane coupling agent layer is sprayed between the organic layer and the inorganic layer.

2. The high-strength rocket launch pad heat-resistant coating according to claim 1, characterized in that, The resin-based heat-resistant coating FRC-100 includes FRC-100A and FRC-100B, wherein the mass ratio of FRC-100A to FRC-100B is 1.22:1; The inorganic matrix material includes water-curing inorganic refractory coating FRC-410, wherein the water:cement mass ratio is 12~13:

100.

3. The high-strength heat-resistant coating for a rocket launch pad according to claim 2, characterized in that, The wire diameter of the wire mesh is 0.1~3mm, the mesh size is 2~8mm, and the material is 304 stainless steel; The concentration of KH-560 silane coupling agent is 0.5%-5%, and the thickness is 5-10μm.

4. A method for preparing a high-strength heat-resistant coating for a rocket launch pad according to any one of claims 1-3, characterized in that, Includes the following steps: Spraying organic layer, coupling agent treatment, spraying inorganic layer; During the spraying of the inorganic layer, two layers of steel wire mesh are embedded within the inorganic layer. The specific steps for laying the steel wire mesh are as follows: Before laying the wire mesh, spray a silane coupling agent onto the surface of the organic layer FRC100 coating. After the anhydrous ethanol in the coupling agent solution has completely evaporated, apply a 2-3 mm thick preliminary inorganic layer evenly to the interface. Then, before the preliminary inorganic layer cures, lay the first layer of wire mesh. Next, spray an intermediate inorganic layer evenly onto the preliminary layer of wire mesh until the total thickness of the inorganic layer reaches 80% of the final thickness. Before the coating cures, lay the second layer of wire mesh. Finally, the construction is completed when the inorganic coating thickness reaches 100%. The inorganic layer thickness is 10~30mm.

5. The method for preparing a high-strength heat-resistant coating for a rocket launch pad according to claim 4, characterized in that, Before laying the wire mesh, a pretreatment process is also included. The wire mesh must be treated with "sandblasting roughening and degreasing" before use.

6. The method for preparing a high-strength rocket launch pad heat-resistant coating according to claim 4, characterized in that, The process preceding the application of the organic layer also includes matrix premixing and fiber dispersion. The matrix premixing step includes premixing of organic layer matrix materials and premixing of inorganic layer matrix materials; The organic layer matrix material includes resin-based heat-resistant coating FRC-100, and the volume content of solid matter in the organic layer is 88%. The premixing operation of the organic layer matrix material is specifically to mix resin-based heat-resistant coating FRC-100: FRC-100A and FRC-100B uniformly by mechanical stirring at room temperature (25°C) for 20 minutes. The inorganic layer matrix material includes water-curing inorganic refractory coating FRC-410, and the volume content of solid matter in the inorganic layer is 100%. The premixing operation of the inorganic layer matrix material is specifically as follows: water is added to the coating in three equal parts at room temperature (25°C) and mechanically stirred, with each operation time being 3 to 5 minutes and the total operation time being 10 to 15 minutes.

7. The method for preparing a high-strength rocket launch pad heat-resistant coating according to claim 6, characterized in that, The fiber dispersion process is as follows: High-silica glass high-temperature resistant inorganic long fibers with a length of 20-30mm are added to the inorganic coating; the long fiber reinforcement is added to the inorganic coating by using the "pre-dispersion-high-speed stirring dispersion method" to ensure that the long fiber reinforcement is uniformly dispersed. First, the long fiber reinforcement and the dry powder component of the inorganic coating are manually premixed in a bag to allow the fibers to be initially encapsulated and separated by the powder. Then, the mixed dry material is slowly added to the liquid component and stirred evenly using a high-power (≥10KW) mixer to ensure uniform fiber dispersion.

8. The method for preparing a high-strength heat-resistant coating for a rocket launch pad according to claim 2, characterized in that, Coupling agent treatment: The coupling agent is applied by low-pressure airless spraying, and the thickness is controlled at 5-10μm.

9. The method for preparing a high-strength heat-resistant coating for a rocket launch pad according to claim 7, characterized in that, It also includes static curing.

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