Aerogel composite metal film thermal insulation material and method of making same

Abstract

The application relates to the technical field of heat insulation material preparation, and discloses an aerogel composite metal film heat insulation material and a preparation method thereof, which comprises the following steps: metal film surface treatment; fiber-metal film needling; through mold forming and porosity control, a fiber-metal film preform with a specific shape and a high porosity structure is prepared; sol immersion and aging; through stage pressure control, efficient penetration and filling of the sol in the fiber-metal film preform are realized, and the conversion of the sol into a gel is completed in a low-temperature aging stage, so that a uniform and stable nanoparticle continuous phase is constructed in the fiber-metal film preform, and a gel-containing fiber-metal film preform is formed; supercritical drying; for the gel-containing fiber-metal film preform, the characteristics of no gas-liquid interface surface tension of an alcohol fluid in a supercritical state are utilized, the solvent is completely removed without destroying the gel network structure, and then the aerogel composite metal film heat insulation material is prepared.

Description

Technical Field

[0001] This invention relates to the field of thermal insulation material preparation technology, and in particular, to an aerogel composite metal film thermal insulation material and its preparation method. Background Technology

[0002] In recent years, the demand for high-performance thermal insulation materials has become increasingly urgent in fields such as aviation, aerospace, nuclear power, shipbuilding, and thermal equipment. Aerogel materials, due to their nanoporous structure, possess extremely low thermal conductivity (typically around 0.012 W / (m·K)), demonstrating significant advantages in high-temperature thermal insulation. Among them, inorganic aerogels, represented by silica, alumina, zirconium oxide, and carbon materials, have become an important research direction in this field due to their excellent high-temperature resistance. Currently, fiber-reinforced silica aerogel composites have achieved some applications, such as thermal insulation components in aerospace vehicle thermal protection systems, flexible thermal insulation felts in petrochemical pipelines, and fireproof thermal insulation pads for new energy battery packs, all exhibiting good thermal insulation performance.

[0003] However, the application of existing silica aerogel composites in high-temperature environments remains significantly limited. Their short-term operating temperature typically does not exceed 800℃, and under high-temperature conditions, especially when the temperature exceeds 1000℃, radiative heat transfer within the material increases significantly, leading to a sharp rise in overall thermal conductivity and severely weakening the insulation effect. Although radiative heat transfer can be suppressed by adding light-blocking agents, the introduction of these agents often faces problems such as uneven particle size distribution and poor dispersion stability, making it difficult to achieve efficient and uniform composite formation. Therefore, it cannot fundamentally improve the thermal performance degradation of the material at high temperatures. Furthermore, existing aerogel composites also suffer from insufficient strength and toughness at high temperatures, limiting their application in large-size, complex-shaped thermal protection components. Summary of the Invention

[0004] This invention provides an aerogel composite metal film thermal insulation material and its preparation method, which can maintain low thermal conductivity over a wide temperature range, while possessing good high temperature resistance, high strength and toughness, and formability. It can be molded into large-size complex components to meet the needs of high-performance thermal protection materials in fields such as aviation, aerospace, and nuclear power. This invention addresses the technical problems of existing silica aerogel composite materials, such as low upper limit of operating temperature, sharp increase in thermal conductivity due to radiative heat transfer at high temperatures, and difficulty in balancing high strength and toughness with complex shape forming.

[0005] According to one aspect of the present invention, a method for preparing an aerogel composite metal membrane thermal insulation material is provided, comprising the following steps: S100, metal membrane surface treatment, wherein contaminants on the surface of the metal membrane are removed and a stable, highly adhesive inorganic protective layer is formed by cleaning, acid etching, and coating a modified layer; S200, fiber-metal membrane needle punching, wherein the bonding force between the metal membrane and the fiber mesh is enhanced by layering and needle punching composite of fibers and metal membrane, thereby obtaining an integrated fiber-metal membrane needle punch part that combines the high-temperature resistance of fibers with the flexibility of metal; S300, preform forming, wherein the integrated fiber-metal membrane needle punch part is formed by molding and porosity control is performed to prepare a material with a specific shape. A fiber-metal membrane preform with a high porosity structure; S400, sol impregnation and aging: through staged pressure control, the sol is efficiently penetrated and filled into the fiber-metal membrane preform, and the sol is converted into a gel during the low-temperature aging stage, thereby constructing a uniform and stable continuous phase of nanoparticles in the fiber-metal membrane preform, forming a gel-containing fiber-metal membrane preform; S500, supercritical drying: for the gel-containing fiber-metal membrane preform, the solvent is completely removed without destroying the gel network structure by utilizing the property of alcohol fluid having no gas-liquid interfacial surface tension in the supercritical state, thereby preparing an aerogel composite metal membrane thermal insulation material.

[0006] Further, the surface treatment of the metal film in step S100 is specifically as follows: S101, immerse the metal film in a solvent at 30℃~60℃, clean it with ultrasound for 5min~30min, air dry it at room temperature, and then place it in an environment at 60℃~100℃ for 0.5h~2h to obtain a clean metal film; S102, immerse the clean metal film in dilute acid at 20℃~60℃ for 3min~60min, remove it and immerse it in deionized water at 40℃~90℃ for 1h~4h, remove it and air dry it, then place it in an oven at 105℃~200℃ for 1h~4h to allow it to dry completely, thus obtaining an acid-treated metal film; S103, immerse the acid-treated metal film in a modification solution and pull it out of the modification solution at a uniform speed of 0.01m / s~0.2m / s, air dry it at room temperature, and then place it in an environment at 300℃~600℃ for 4h~12h to obtain a surface-treated metal film.

[0007] Furthermore, the solvent in step S101 is any one of acetone, ethanol, and isopropanol.

[0008] Furthermore, the dilute acid in step S102 is any one of hydrochloric acid, nitric acid, or sulfuric acid aqueous solution, with a mass fraction of 0.2% to 2%.

[0009] Further, the fiber-metal film needle punching in step S200 specifically involves: laying a fiber mesh on a tooling, then laying a surface-treated metal film on the fiber mesh, and needle punching the fiber mesh and metal film using fiber threads; repeating this process layer by layer to lay and needle punch the fiber mesh and metal film to form a fiber-metal film needle punch.

[0010] Furthermore, the fiber mesh is any one of rock wool, glass fiber, quartz fiber, aluminosilicate fiber, high-silica fiber, zirconium oxide fiber, alumina fiber, and mullite fiber, with an average fiber diameter of 0.5μm to 10μm, an aspect ratio of 5000 to 20000, and a thickness of 0.5mm to 5mm; and / or the fiber thread is any one of rock wool, glass fiber, quartz fiber, high-silica fiber, and alumina fiber, with an average fiber diameter of 5μm to 12μm; and / or the fiber thread has a mass fraction of 5% to 12% in the overall fiber-metal film needled part.

[0011] Further, the preform forming in step S300 specifically involves: using a mold to form the fiber-metal film needled part into a fiber-metal film preform of a specified shape, wherein the porosity of the fiber-metal film preform is between 89% and 97%.

[0012] Further, the preform forming in step S400 specifically involves: immersing the fiber-metal membrane preform in a sol at a pressure of -0.1 MPa to -0.09 MPa for 0.5 h to 3 h; then immersing it in the sol at a pressure of 0.5 MPa to 2.0 MPa for 0.5 h to 3 h to obtain a sol-impregnated fiber-metal membrane preform; and then immersing the sol-impregnated fiber-metal membrane preform in a temperature of 40 °C to 70 °C for 12 h to 24 h to form a gel-containing fiber-metal membrane preform.

[0013] Furthermore, the sol is any one of silica sol, zirconium oxide sol, and alumina sol, with a solid content of 8% to 25% and an average particle size of 3 nm to 60 nm.

[0014] Furthermore, the solvent used in the sol is any one of ethanol, isopropanol, n-propanol, n-butanol, sec-butanol, and tert-butanol.

[0015] Further, the supercritical drying in step S500 is specifically as follows: the fiber-metal membrane preform containing gel is placed in an autoclave, an alcohol is added and kept sealed, and heated to above the critical point of the alcohol and kept for 8 to 16 hours. The gas in the autoclave is slowly discharged until the pressure is 0, and the aerogel composite metal membrane insulation material is obtained.

[0016] Furthermore, the alcohol is any one of ethanol, isopropanol, n-propanol, n-butanol, sec-butanol, and tert-butanol.

[0017] Furthermore, the metal film in step S100 is any one of aluminum alloy, titanium alloy, copper, stainless steel, silver, gold, iron-chromium-aluminum, nickel alloy, and molybdenum alloy, with a thickness of 2μm to 50μm.

[0018] According to another aspect of the present invention, an aerogel composite metal film thermal insulation material is also provided, which is prepared by the above-described method for preparing aerogel composite metal film thermal insulation material.

[0019] The present invention has the following beneficial effects:

[0020] 1. Significantly improves temperature resistance and high-temperature thermal insulation stability: By forming a stable inorganic protective layer on the surface of the metal film, the oxidation and failure of the metal components at high temperatures are effectively suppressed, thereby significantly increasing the upper limit of the material's operating temperature; the introduced metal film layer acts as an excellent radiation shielding agent at high temperatures, far superior to traditional doped micron-sized particle shielding agents; the metal film can efficiently reflect and block radiative heat transfer in high-temperature environments, thereby significantly suppressing the increase in thermal conductivity caused by intensified radiative heat transfer at temperatures of 600℃ and above, achieving sustained low thermal conductivity of the material over a wide temperature range (from room temperature to ultra-high temperature).

[0021] 2. Achieving integrated strength and toughness of materials: Through the fiber-metal membrane stacking and needle punching process, the strength of high-temperature resistant fibers is organically combined with the flexibility and ductility of the metal membrane to form a three-dimensional interpenetrating integral structure. This not only endows the preform with excellent mechanical strength and toughness, making it less prone to cracking or damage in subsequent processing and practical applications, but also provides a stable skeleton support for subsequent sol impregnation. Ultimately, the resulting aerogel composite material has both high strength and good toughness, overcoming the shortcomings of traditional aerogel materials with high brittleness.

[0022] 3. Ensuring the uniformity and integrity of the nanostructure: The staged pressure-controlled sol impregnation process ensures efficient and uniform penetration and filling of the sol in the high-porosity and complex fiber-metal membrane preform, avoiding the generation of unfilled areas or defects; combined with supercritical drying technology, the solvent is completely removed under the action of non-destructive capillary forces, and the gel network and its nanoporous structure combined with the fiber and metal membrane are completely preserved, so that the aerogel nanophase can be uniformly and stably distributed in the entire reinforcing skeleton, which is the structural basis for achieving the excellent thermal insulation and mechanical properties of the material.

[0023] 4. Capable of forming complex components: The preform forming step uses a mold to shape and control the porosity of the needle-punched parts, enabling the method to produce preforms with specific shapes and high porosity. Combined with uniform impregnation and drying technology, this ensures that the final product can be formed into large-size, complex thermal insulation components, greatly expanding the application scenarios of the material and meeting the urgent need for complex-shaped thermal insulation components.

[0024] 5. Synergistic Effect of Each Step: The entire process is interconnected. Surface treatment ensures the stability of the metallic phase, needle-punching composite construction creates a strong and tough framework, molding process gives the product shape adaptability, impregnation technology ensures the uniform composite of nanomaterials, and supercritical drying technology effectively avoids structural collapse, shrinkage, or agglomeration caused by surface tension during traditional drying processes, thus completely preserving the original nanoscale network structure of the material. Each step supports and works synergistically to achieve a leap in product performance. The prepared aerogel composite metal film thermal insulation material withstanding 1400℃ has a density of 0.38 g / cm³. 3 After being heated to 1400℃ on one side for 1 hour, no interfacial delamination occurs, and the thickness shrinkage rate is 0.7%; the thermal conductivity at room temperature and 1400℃ is 0.028W / (m·K) and 0.051W / (m·K), respectively; the tensile strength is 2.8MPa, and the flexural strength is 3.5MPa; it can be molded into components with dimensions of 1500mm×800mm×60mm.

[0025] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0026] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0027] Figure 1 This is a photograph of the fiber-metal membrane needle-punched part according to Embodiment 3 of the present invention;

[0028] Figure 2 This is a photograph of the aerogel composite metal film thermal insulation material of Embodiment 3 of the present invention. Detailed Implementation

[0029] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below. Unless otherwise stated, the raw materials and reagents used in the following embodiments are commercially available or can be prepared by known methods.

[0030] The preparation method of the aerogel composite metal membrane thermal insulation material in this embodiment includes the following steps: S100, metal membrane surface treatment, which removes contaminants from the metal membrane surface and forms a stable, highly adhesive inorganic protective layer through cleaning, acid etching, and coating a modified layer; S200, fiber-metal membrane needle punching, which enhances the bonding force between the metal membrane and the fiber mesh through the layered needle punching composite of fibers and metal membrane, resulting in an integrated fiber-metal membrane needle punch part that combines the high-temperature resistance of fibers with the flexibility of metal; S300, preform molding, which involves molding the integrated fiber-metal membrane needle punch part using a mold and controlling its porosity to prepare a material with a specific shape and high porosity. A fiber-metal membrane preform with a high efficiency structure; S400, sol impregnation and aging, through staged pressure control, achieves efficient penetration and filling of the sol in the fiber-metal membrane preform, and completes the transformation of the sol to gel in the low-temperature aging stage, thereby constructing a uniform and stable continuous phase of nanoparticles in the fiber-metal membrane preform, forming a fiber-metal membrane preform containing gel; S500, supercritical drying, for the fiber-metal membrane preform containing gel, utilizes the characteristic of alcohol fluid having no gas-liquid interfacial surface tension in the supercritical state to completely remove the solvent without destroying the gel network structure, thereby preparing an aerogel composite metal membrane thermal insulation material. This invention discloses a method for preparing aerogel composite metal film thermal insulation material. By forming a stable inorganic protective layer on the surface of the metal film, the oxidation and failure of the metal components at high temperatures are effectively suppressed, thereby significantly increasing the upper limit of the material's operating temperature. The introduced metal film layer acts as an excellent radiation shielding agent at high temperatures, far superior to traditional doped micron-sized particle shielding agents. The metal film can efficiently reflect and block radiative heat transfer in high-temperature environments, thus significantly suppressing the increase in thermal conductivity caused by intensified radiative heat transfer at temperatures of 600°C and above, achieving a sustained low thermal conductivity across a wide temperature range (from room temperature to ultra-high temperature). Through a fiber-metal film lamination and needle-punching process, the strength of high-temperature resistant fibers is organically combined with the flexibility and ductility of the metal film, forming a three-dimensional interpenetrating integral structure. This not only endows the preform with excellent mechanical strength and toughness, making it less prone to cracking or damage in subsequent processing and practical applications, but also provides stable skeletal support for subsequent sol impregnation. Ultimately, the resulting aerogel composite material possesses both high strength and good toughness, overcoming the shortcomings of traditional aerogel materials with high brittleness. The staged pressure-controlled sol-gel impregnation process ensures efficient and uniform penetration and filling of the sol in the high-porosity and complex fiber-metal membrane preform, avoiding the generation of unfilled areas or defects. Combined with supercritical drying technology, the solvent is completely removed under the action of non-destructive capillary forces, and the gel network and its nanoporous structure combined with the fiber and metal membrane are completely preserved. This allows the aerogel nanophase to be uniformly and stably distributed throughout the entire reinforcing skeleton, which is the structural basis for achieving the material's excellent thermal insulation and mechanical properties.The preform molding step uses a mold to shape and control the porosity of the needle-punched parts, enabling the production of preforms with specific shapes and high porosity. Combined with uniform impregnation and drying technologies, this ensures the final product can be molded into large-size, complex thermal insulation components, greatly expanding the material's application scenarios and meeting the urgent need for complex-shaped thermal insulation components. The entire process is interconnected: surface treatment ensures the stability of the metallic phase, needle-punching composites construct a strong and tough framework, the molding process gives the product shape adaptability, impregnation technology ensures the uniform composite of nanomaterials, and supercritical drying technology effectively avoids structural collapse, shrinkage, or agglomeration caused by surface tension during traditional drying processes, thus fully preserving the original nanoscale network structure of the material. Each step supports and synergistically works to achieve a leap in product performance. The prepared aerogel composite metal membrane thermal insulation material, resistant to 1400℃, has a density of 0.38 g / cm³. 3 After being heated to 1400℃ on one side for 1 hour, no interfacial delamination occurred, and the thickness shrinkage rate was 0.7%. The thermal conductivity at room temperature and 1400℃ was 0.028 W / (m·K) and 0.051 W / (m·K), respectively. The tensile strength was 2.8 MPa, and the flexural strength was 3.5 MPa. Components with a formability of 1500 mm × 800 mm × 60 mm were successfully prepared using an innovative process combining fiber-metal membrane needle-punching composite and staged pressure impregnation. This process effectively solved the technical bottlenecks of traditional aerogel composite materials, such as insufficient temperature resistance, low thermal conductivity over a wide temperature range, high strength and toughness, and the ability to be complexly molded. It provides an ideal high-performance thermal protection solution for the high-end equipment field.

[0031] In this embodiment, the surface treatment of the metal film in step S100 is specifically as follows: S101, the metal film is immersed in a solvent at 30℃~60℃, ultrasonically cleaned for 5min~30min, air-dried at room temperature, and then placed in an environment at 60℃~100℃ for 0.5h~2h to obtain a clean metal film; S102, the clean metal film is immersed in dilute acid at 20℃~60℃ for 3min~60min, then removed and immersed in deionized water at 40℃~90℃ for 1h~4h, then removed and air-dried, and placed in an oven at 105℃~200℃ for 1h~4h to fully dry it to obtain an acid-treated metal film; S103, the acid-treated metal film is immersed in a modification solution and pulled out of the modification solution at a uniform speed of 0.01m / s~0.2m / s, air-dried at room temperature, and then placed in an environment at 300℃~600℃ for 4h~12h to obtain a surface-treated metal film. By employing a solvent-based ultrasonic cleaning method, utilizing the cavitation effect of ultrasound, oil, dust, and other organic and inorganic contaminants can be effectively and thoroughly removed from the surface and micropores of the metal film. Subsequent heat treatment further removes residual solvents and potentially adsorbed moisture, ensuring the absolute cleanliness of the metal film surface. This provides a pollution-free, highly active initial interface for subsequent acid etching and final bonding with fibers and aerogel, avoiding the risk of weakened or failed bonding due to interface contamination. Controlled temperature, concentration, and time of dilute acid etching allow for controlled and uniform mild corrosion of the clean metal film surface, forming specific micro-nano-scale rough structures that significantly increase its specific surface area. This roughened surface morphology, when combined with fiber needle bonding, enables stronger mechanical interlocking (anchoring) with the fiber filaments, greatly enhancing the mechanical bonding between the metal film and the fiber continuous phase and preventing interface contamination during use. The process involves surface layering; a modified liquid is coated using a specific speed-lift dip-coating method followed by medium-to-high temperature heat treatment. This process forms a stable, dense, and highly adhesive inorganic protective layer on the rough metal film surface after acid treatment. The key function of this protective layer is to isolate the easily oxidized metal substrate from the high-temperature environment, effectively inhibiting its oxidation, corrosion, and pulverization under high-temperature service conditions. This significantly increases the upper limit of the metal film's operating temperature, ensuring its structural integrity and functionality at high temperatures. The inorganic protective layer itself has better chemical compatibility and bonding with the subsequently impregnated aerogel sol, providing a bridge for the stable and firm bonding of the metal phase and the inorganic aerogel phase. The key parameters such as temperature, time, and lift-coating speed of each sub-step are precisely limited to ensure the controllability of the surface treatment reaction and the uniformity and reproducibility of the treatment effect. This facilitates the preparation of large-size, uniformly performing composite material components, avoiding performance bottlenecks or failure sources caused by poor local treatment.The metal film surface treatment process is a key innovative step in precisely constructing a high-performance interface through a three-step method of "cleaning-roughening-protection". Through synergistic effects, it not only completely removes interface contaminants, but also significantly enhances the mechanical bonding force between the metal film and the fiber. Furthermore, it fundamentally solves the problem of oxidation failure of metal films at high temperatures by constructing a stable inorganic protective layer.

[0032] In this embodiment, the solvent in step S101 is any one of acetone, ethanol, and isopropanol. Acetone, ethanol, and isopropanol are all polar organic solvents with good lipophilicity, oilophilicity, and strong dissolving power. This allows them to efficiently dissolve and remove organic contaminants such as grease, release agents, and fingerprints adhering to the surface of the metal film during production, transportation, and storage, thereby achieving thorough cleaning of the metal film. The selected three solvents all have moderate volatility, ensuring that they can be completely and thoroughly removed from the surface and microstructure of the metal film during subsequent room temperature drying and low-temperature drying steps. Residue will not adversely affect subsequent acid etching or modified layer coating (such as causing uneven reactions or defects). Furthermore, compared to more toxic solvents (such as benzene and chloroform), these three solvents are safer and less toxic in industrial operations. The low surface tension and viscosity of acetone, ethanol, and isopropanol are more in line with the requirements of green environmental protection and safe production. The principle of ultrasonic cleaning is to use the cavitation effect to generate a strong impact force to remove contaminants. Acetone, ethanol, and isopropanol have low surface tension and low viscosity, which is very conducive to the transmission of ultrasonic energy in the solution and the formation and collapse of cavitation bubbles. This can significantly enhance the cleaning efficiency and effect of ultrasonic cleaning, and achieve deep cleaning of contaminants on the surface of metal films and micro-depressions. Under controlled temperature and time conditions, acetone, ethanol, and isopropanol do not have significant corrosiveness or chemical damage to common metal materials (such as stainless steel, aluminum, nickel-based alloys, etc.). This allows the cleaning process to effectively remove contaminants while keeping the chemical composition and mechanical properties of the metal film substrate itself intact. It is a gentle and efficient cleaning solution.

[0033] In this embodiment, the dilute acid in step S102 is any one of hydrochloric acid, nitric acid, or sulfuric acid aqueous solution, with a mass fraction of 0.2% to 2%. The selected hydrochloric acid, nitric acid, and sulfuric acid are all strong inorganic acids, capable of effectively chemically etching most metal surfaces (such as stainless steel and aluminum alloys). Strictly controlling the concentration within this low range of 0.2% to 2% aims to achieve gentle and controllable corrosion of the metal film surface. This removes the extremely thin surface oxide film and contaminants while forming a uniform and fine micro-nano-scale rough structure on the metal surface, significantly increasing its specific surface area. This provides excellent mechanical anchoring points for the needle-punching composite of fibers and the metal film in subsequent steps, greatly enhancing the mechanical bonding force between the metal film and the reinforcing fibers. This is crucial to preventing interfacial delamination under thermal stress. Strong acid treatment not only cleans and roughens the surface but also effectively activates the metal surface. The acid etching process removes the inert oxide layer, exposing a fresh metal surface with higher surface energy and more active sites. This activated surface can generate stronger chemical interactions with the modified liquid applied in subsequent steps. The process (such as forming hydrogen bonds or undergoing chemical reactions) significantly improves the adhesion between the inorganic protective layer and the metal substrate, ensuring the stability of the protective layer at high temperatures. A mass fraction of 0.2% is the lower limit of effectiveness, ensuring that even for highly corrosion-resistant metals, effective surface treatment and activation can be completed within a reasonable time (3 min to 60 min). A mass fraction of 2% is the upper limit of safety, preventing over-etching due to excessive acid concentration. Over-etching can disrupt the uniformity of the metal surface and may even damage the mechanical integrity of the metal film itself (such as causing intergranular corrosion or excessive thinning). The 0.2%–2% concentration range achieves the best balance between ensuring treatment effectiveness and protecting the substrate from damage. The use of aqueous solutions, rather than organic acid or alcohol solutions, is recommended due to its low cost, ease of access, and simple operation. The aqueous system also facilitates subsequent cleaning steps, avoiding potential residue or compatibility issues caused by introducing other organic solvents.

[0034] In this embodiment, the fiber-metal film needle punching in step S200 specifically involves: laying a fiber mesh on a tooling, then laying a surface-treated metal film on the fiber mesh, and needle punching the fiber mesh and metal film using fiber threads; repeating this process layer by layer to lay and needle the fiber mesh and metal film to form a fiber-metal film needled part. Through the alternating layering and needle punching of the fiber mesh and metal film, and using fiber threads as the guide and reinforcing material for the needles, the flexible fiber mesh and tough metal film are physically interwoven together in three-dimensional space. The fiber threads pass through the metal film, tightly connecting the upper and lower layers of the fiber mesh, forming a three-dimensional interpenetrating, isotropic composite skeleton structure. This structure combines the high strength and high temperature resistance of fiber materials with the flexibility and ductility of metal materials, resulting in a needled part that exhibits excellent structural strength, tear resistance, and impact toughness on a macroscopic scale. This fundamentally overcomes the defects of traditional aerogel or ceramic materials, such as high brittleness and easy cracking, and provides a basis for subsequent processing and applications. The needle-punching process provides reliable mechanical support. The mechanical force creates a strong mechanical interlocking and frictional anchoring effect between the fiber threads and the metal film, as well as between different layers. This mechanically interlocked bonding method results in a bonding strength far exceeding that of simple physical adsorption or lamination. This is particularly evident on surface-roughened metal films, where the fiber hooking effect is even more pronounced. This robust interfacial bonding ensures that the material effectively resists internal stresses caused by differences in the thermal expansion coefficients of its components during subsequent sol-gel impregnation, drying, and service under high-temperature thermal stress conditions. This prevents interlayer separation or detachment, ensuring the long-term integrity of the material structure. While densely bonding the layers, the needle-punching process does not completely compact the material. Instead, it creates continuous and open three-dimensional network pore channels supported by fibers and fiber threads between and within the layers. This provides the necessary diffusion channels and space for efficient sol penetration and uniform filling in subsequent steps, ensuring that the aerogel nanophase is uniformly distributed throughout the reinforcing framework, thereby achieving low thermal conductivity and uniform mechanical properties. The laying and needle punching processes do not require high temperature and high pressure and can be carried out at room temperature. The equipment requirements are relatively simple. By controlling the number of fiber mesh layers, the laying method of the metal film, and the density and depth of needle punching, the thickness, density and metal content of the final preform can be flexibly adjusted. It can adapt to tooling molds of different shapes and sizes, laying the foundation for the subsequent preparation of complex components of specific shapes.

[0035] In this embodiment, the fiber mesh is any one of rock wool, glass fiber, quartz fiber, aluminosilicate fiber, high-silica fiber, zirconium oxide fiber, alumina fiber, and mullite fiber, with an average fiber diameter of 0.5μm to 10μm, an aspect ratio of 5000 to 20000, and a thickness of 0.5mm to 5mm; and / or the fiber thread is any one of rock wool, glass fiber, quartz fiber, high-silica fiber, and alumina fiber, with an average fiber diameter of 5μm to 12μm; and / or the fiber thread has a mass fraction of 5% to 12% in the overall fiber-metal film needled part. The selected fiber mesh and fiber yarn materials both belong to the category of inorganic high-temperature resistant fibers. These materials possess high melting or softening points, enabling them to withstand high-temperature environments for extended periods, thus ensuring the high-temperature resistance of the final composite material. Their structural stability at high temperatures is far superior to that of materials reinforced with organic fibers. The average fiber diameter of the fiber mesh is limited to 0.5μm–10μm (micrometer level), with an aspect ratio as high as 5000–20000. The extremely fine and long fibers result in a very high number of fibers per unit mass or volume, providing an extremely high specific surface area. This not only provides conditions for forming denser mechanical engagement points with the metal film during needle punching but also generates a larger area of ​​interfacial bonding and stronger confinement when providing a deposition framework for subsequent aerogel nanoparticles. This is beneficial for constructing a more uniform and stable composite structure, thereby synergistically reducing the thermal conductivity of the material and enhancing its mechanical properties. The thickness of the fiber mesh (0.5mm–5mm) is... The design, in conjunction with the layer-by-layer laying process, allows for flexible and precise adjustment of the final preform's total thickness and bulk density by controlling the number of layers. The average diameter of the fiber strands (5μm~12μm) is slightly thicker than that of the mesh fiber, giving them sufficient rigidity and strength to effectively penetrate the metal membrane during needle punching and tightly hook the layers together, acting as a riveting reinforcement to form a stable three-dimensional skeleton. The mass fraction of fiber strands in the overall needle-punched part is controlled at 5%~12%, ensuring a sufficient amount of fiber strands to form dense needle punches, thereby providing the necessary interlayer bonding strength and overall structural integrity. This content is also limited to a certain level to avoid the preform becoming too dense and significantly reducing porosity due to excessive fiber strand usage, which would affect the penetration and uniformity of subsequent sol-gel impregnation. Ultimately, this ensures that the material maintains high strength while retaining low density and excellent thermal insulation properties.

[0036] In this embodiment, the preform forming in step S300 specifically involves: using a mold to form the fiber-metal film needled part into a fiber-metal film preform of a specified shape, wherein the porosity of the fiber-metal film preform is between 89% and 97%. The use of molds to form fiber-metal membrane needled parts allows for the shaping of needled parts that might otherwise be felt-like or flat into specified shapes with complex three-dimensional structures. This endows the final product with a high degree of shape adaptability and design freedom, enabling it to directly meet the urgent needs of aerospace and other fields for thermal insulation components with specific shapes (such as irregular curved surfaces, components with flanges or protrusions), greatly expanding the application range of the material. Precisely controlling the porosity of the preform within the extremely high range of 89%–97% (through the synergistic control of the fiber mesh, metal membrane, and fiber threads) ensures that the main body of the composite material is composed of air (an excellent thermal insulator). This lays the foundation for the material to achieve extremely low intrinsic thermal conductivity. This high and continuous pore network structure facilitates the efficient penetration and uniform filling of aerogel sol in subsequent steps, ultimately forming a continuous and stable aerogel nanonetwork. It provides sufficient and necessary space to ensure uniform distribution of the aerogel phase and avoid unfilled defects; it shapes the preform without significantly damaging or compressing the original high-porosity structure of the needled part; through reasonable mold design and molding pressure control, it achieves a balance between shaping and preserving the high-porosity structure, ensuring that the preformed part retains interconnected open pores while achieving a specific shape, creating conditions for subsequent sol-gel impregnation; molding ensures that preforms of the same shape produced in different batches have highly consistent geometric dimensions and bulk density; combined with precise control of the porosity range, the subsequent sol-gel impregnation, aging, and drying processes can be carried out in a stable and controllable framework structure, improving the uniformity of the final aerogel composite product's performance and batch-to-batch reproducibility, meeting the stringent reliability requirements of high-end industrial applications.

[0037] In this embodiment, the preform forming in step S400 specifically involves: immersing the fiber-metal membrane preform in a sol at a pressure of -0.1 MPa to -0.09 MPa for 0.5 h to 3 h; then maintaining the sol-impregnated fiber-metal membrane preform at a pressure of 0.5 MPa to 2.0 MPa for 0.5 h to 3 h to obtain the sol-impregnated fiber-metal membrane preform; and then maintaining the sol-impregnated fiber-metal membrane preform at a temperature of 40 °C to 70 °C for 12 h to 24 h to form a gel-containing fiber-metal membrane preform. A staged pressure control strategy, employing initial negative pressure (-0.1MPa to -0.09MPa) followed by positive pressure (0.5MPa to 2.0MPa), produced a synergistic impregnation effect. The initial negative pressure environment effectively extracted air trapped in the complex three-dimensional pore network of the preform, overcoming impregnation obstacles caused by capillary effects and air resistance, thus clearing the channels for sol entry. The subsequent applied moderate positive pressure acted as an active driving force, propelling the sol to rapidly enter and fill the pre-cleaned pore network, ensuring efficient, deep, and uniform penetration of the sol even in the finest and most tortuous pores. This effectively avoided unfilled areas or defects caused by incomplete impregnation, thereby facilitating the formation of a uniform gel network. Strictly controlling the aging temperature within a low range of 40℃ to 70℃ and maintaining a sufficient time of 12h to 24h provided a mild and controllable gelation environment. The low temperature allowed the sol to complete the transformation from sol to gel relatively slowly and synchronously throughout the preform, resulting in a uniform gelation process. Furthermore, the slow phase transition process effectively prevents problems such as internal stress accumulation, microcracks, or phase separation that may occur due to excessively rapid reactions, uneven local concentrations, or drastic volume changes, thus ensuring the integrity and uniformity of the final gel network structure. The gentle and thorough aging process not only generates gel but also enables the newly generated gel nanoparticles to form a sufficient and strong interfacial bond with the fiber-metal membrane skeleton. This strong interfacial bond provides the foundation for the excellent mechanical properties (such as strength and toughness) and thermal stability of the final composite material, ensuring that the nanophase will not detach from the skeleton during subsequent drying and high-temperature use. The pressure range, pressure holding time, and aging temperature and time for each stage are precisely defined, making the impregnation and aging process highly controllable and reproducible. For preforms of different batches and shapes and sizes, consistent and reliable impregnation and gelation effects can be obtained through this parameter system, thereby ensuring the uniformity and stability of the final aerogel composite product performance.

[0038] In this embodiment, the sol is any one of silica sol, zirconium oxide sol, and alumina sol, and the solid content of the sol is 8% to 25%, with an average particle size of 3 nm to 60 nm. The selected silica sol, zirconium oxide sol, and alumina sol are all inorganic oxide sols. The resulting gels, after drying, transform into their corresponding inorganic aerogels (such as SiO2, ZrO2, and Al2O3), possessing extremely high melting points and excellent thermal stability. This provides a fundamental guarantee for the high-temperature resistance of the final composite material, enabling it to withstand high-temperature environments and form a stable thermal insulation system across a wide temperature range together with high-temperature resistant fibers and metal films. The selected inorganic oxide sols (especially silica sols) are chemically similar to the inorganic protective layers on the fiber mesh and metal film surfaces, exhibiting good chemical compatibility. This reduces potential adverse chemical reactions between different phases and promotes the formation of a stable interface between the gel and the skeleton, which is beneficial for the long-term stability of the composite material at high temperatures. The average particle size of the sol particles is controlled within the nanoscale range of 3nm to 60nm to facilitate efficient and uniform filling. Extremely small nanoparticles (as low as 3nm) are also used. (m) This gives it good fluidity, allowing it to penetrate into the finest pores and fiber gaps of the preform along with the sol solution. Due to their high specific surface area and surface energy, nanoscale particles are more likely to form strong physical adsorption or chemical bonding with the fiber and metal film surfaces, thereby enhancing the interfacial bonding force between the aerogel phase and the reinforcing skeleton, which is conducive to the formation of a uniform and stable composite structure. The setting of sol solid content of 8% to 25% can achieve a balance between low density and high porosity structure in the final material. The lower limit of 8% solid content ensures that there are enough precursor materials to form a continuous, complete gel network that can support its own structure after aging, avoiding the collapse of the gel skeleton due to insufficient strength caused by too low solid content during drying. The upper limit of 25% solid content prevents the sol viscosity from increasing due to excessively high precursor concentration, which would affect its permeability and uniformity in high-porosity preforms. At the same time, it can also prevent the final aerogel phase from being too dense, which would increase the overall density and thermal conductivity of the material.

[0039] In this embodiment, the solvent used for the sol is any one of ethanol, isopropanol, n-propanol, n-butanol, sec-butanol, and tert-butanol. Step S400 specifies the use of this particular alcohol as the solvent for the sol, perfectly matching and synergizing with the supercritical drying process. Supercritical drying explicitly uses alcohol fluids as the supercritical medium, and the solvent used in step S400 is consistent with or similar in type to the supercritical drying medium (both being alcohols), ensuring a successful and efficient process. This allows the solvent within the gel pores to achieve complete miscibility with the external supercritical fluid during drying, thus being completely replaced and removed in a phase-interface-free state. If other types of solvents (such as water) are used, a cumbersome solvent replacement step that could potentially damage the structure is required. This choice greatly simplifies the process and fundamentally avoids the risk of gel network collapse due to improper solvent replacement. In sol-gel chemical reactions, alcohol solvents (such as ethanol and isopropanol) are usually not only solvents but also participate in hydrolysis, condensation, and other reaction processes. Their molecular structure and steric hindrance effects can gently regulate the reaction rate. Compared with systems using water as a solvent, the hydrolysis reaction in alcohol solvent systems is usually milder and more controllable, which is conducive to the formation of a more uniform and denser gel network structure and avoids local stress or particle agglomeration caused by excessively fast reactions. This provides a chemical guarantee for obtaining high-performance aerogel structures. The selected alcohol solvents have good wettability on the inorganic protective layer of metal films treated with S100 and the surfaces of various inorganic fibers, ensuring that the sol can fully spread and penetrate into the complex pore structure and fiber surface of the preform, rather than forming droplets that hinder penetration. This facilitates uniform impregnation of the sol and ultimately obtains a defect-free composite structure. When water is used as a solvent, its high polarity may promote the hydrolysis or corrosion of certain metal components (despite the protective layer); while using organic alcohol solvents can provide a relatively inert chemical environment, effectively suppressing such side reactions that may damage the metal film or fiber skeleton, and ensuring the chemical stability of the continuous phase structure during gelation.

[0040] In this embodiment, the supercritical drying in step S500 specifically involves: placing the gel-containing fiber-metal membrane preform in an autoclave, adding an alcohol and keeping it sealed, heating to above the critical point of the alcohol and maintaining this temperature for 8 to 16 hours, and slowly releasing the gas from the autoclave until the pressure is zero to obtain the aerogel composite metal membrane insulation material. This utilizes the characteristic of alcohol fluids in a supercritical state (both temperature and pressure above the critical point) where there is no gas-liquid interface and the surface tension is zero. In this state, the liquid in the gel pores is directly converted into an indiscriminate supercritical fluid, and by slowly releasing the pressure, it escapes directly. This completely removes the solvent without damaging or shrinking the original three-dimensional nanoporous framework of the gel, thus completely preserving the nanoporous structure formed after aging. This completely avoids the huge capillary force generated by liquid evaporation during traditional drying processes (this destructive capillary force is the root cause of gel network collapse, shrinkage, and cracking). In step S400, the solvent used for the sol is a specific alcohol. Step S500 also uses the same type of alcohol as the supercritical drying medium, ensuring that the solvent within the gel pores is completely compatible and miscible with the drying medium added to the autoclave. This eliminates the need for an intermediate solvent replacement process that could potentially damage the structure, achieving a direct, efficient, and harmless conversion from wet to dry gel, significantly improving process reliability and yield. By successfully eliminating drying damage, an aerogel material with extremely high porosity and a large specific surface area was ultimately obtained in situ within the pores of the fiber-metal membrane preform. This nanoporous structure is filled with a large amount of air, thus endowing the entire composite material with extremely low solid-state thermal conductivity and extremely low gas-phase thermal conductivity, achieving ultra-low thermal conductivity. Simultaneously, the intact nanostructure provides numerous interfacial bonding points, contributing to enhanced overall mechanical properties of the material. Setting the supercritical state holding time to 8-16 hours ensures sufficient time for the supercritical fluid to slowly and uniformly penetrate the entire gel, completely carrying away the solvent from all areas. The process of slowly depressurizing to atmospheric pressure avoids structural disturbances or damage that may be caused by a sudden drop in pressure. The combined effect of these parameters in the supercritical drying process of step S500 ensures that the gel throughout the component, regardless of its size, can complete the drying process synchronously and completely, resulting in a final product with a uniform structure and no defects.

[0041] In this embodiment, the alcohol is any one of ethanol, isopropanol, n-propanol, n-butanol, sec-butanol, and tert-butanol. The solvent used in step S400 for sol preparation is an alcohol of the same type, ensuring that the solvent in the gel pores has high chemical similarity and complete miscibility with the supercritical drying medium added to the autoclave. Therefore, during the process of increasing pressure and temperature to the supercritical state, the solvent in the pores can rapidly and uniformly mix with the external medium without any intermediate solvent replacement steps that could damage the gel structure. This consistent design greatly simplifies the process and completely avoids the risk of structural collapse caused by solvent incompatibility, incomplete replacement, or volume changes, ensuring a high drying success rate and product integrity. The listed alcohols (such as ethanol and isopropanol) have relatively moderate critical temperatures (typically in the range of 200℃ to 300℃) and critical pressures (typically in the range of 4MPa to 6MPa) compared to some media with extremely high critical parameters, such as water (Tc=374℃, Pc=22MPa). Alcohols allow supercritical drying processes to be carried out under relatively lower temperature and pressure conditions, reducing the requirements for autoclave equipment, decreasing energy consumption, and significantly improving the safety and controllability of the process, making it easier to implement and promote in industrial production. Under supercritical conditions, the listed alcohol media provide a relatively stable environment for the gel and the entire preform. An inert chemical environment effectively avoids adverse chemical reactions that may occur under high temperature and high pressure conditions due to the presence of water, oxygen, or other active media, such as oxidation of metal films, hydrolysis of fibers, or degradation of gel network structures. This ensures the chemical stability of all material components during the drying process. The listed alcohols have low viscosity and high diffusion coefficient in the supercritical state, enabling them to quickly penetrate into the fine pores of the innermost part of the composite preform and effectively carry out the dissolved solvent, thereby ensuring that the entire component achieves a uniform and thorough drying effect inside and out, avoiding structural weaknesses or performance differences due to incomplete local drying.

[0042] In this embodiment, the metal film in step S100 is any one of aluminum alloy, titanium alloy, copper, stainless steel, silver, gold, iron-chromium-aluminum, nickel alloy, and molybdenum alloy, with a thickness of 2μm to 50μm. The selection of the metal film material and thickness is based on a precise design of its function in the composite material (mechanical reinforcement, radiation heat shielding, and high-temperature stability). The selected metal materials (such as aluminum alloy, titanium alloy, stainless steel, silver, iron-chromium-aluminum, and nickel alloy) all have the characteristics of high reflectivity and low infrared emissivity. Introducing them into the composite material in the form of a thin film can efficiently reflect and block heat radiation transfer in a high-temperature environment, solving the technical problem of increased thermal conductivity of aerogel materials due to the sharp increase in radiation heat transfer at high temperatures. The light-shielding effect of the selected metal materials is far superior to that of traditional doped micron-sized particle light-shielding agents, and can better achieve the material to maintain low thermal conductivity over a wide temperature range. By fabricating metals into ultra-thin films ranging from 2μm to 50μm, the metal retains its inherent strength and ductility while achieving exceptional flexibility and processability. This allows the metal film to be smoothly needle-punched and bonded to fiber mesh, and to adapt to complex mold shapes without brittle fracture. These properties of the metal film, combined with the strength of the fibers, endow the entire composite material with excellent toughness, thermal shock resistance, and mechanical impact resistance, overcoming the inherent brittleness of traditional ceramics or aerogel materials. The lower thickness limit of 2μm ensures sufficient continuity, mechanical strength, and effective blocking of radiant heat (optical thickness) for the metal film; the upper thickness limit of 50μm strictly restricts the absolute mass of the metal film, preventing a significant increase in the overall density of the composite material due to its higher density, which would violate the fundamental requirement of lightweight insulation materials. The thickness range of 2μm to 50μm achieves the optimal balance between functionality and maintaining the material's lightweight properties. The selected metal materials cover a wide range, from high-strength lightweight alloys (such as aluminum alloys and titanium alloys) to high-melting-point heat-resistant alloys (such as iron-chromium-aluminum, nickel alloys, and molybdenum alloys) to highly reflective precious metals (such as silver and gold). They are highly flexible and adaptable, and the most suitable metal film material can be selected according to the specific application scenario (such as the maximum operating temperature, corrosion resistance environment, cost considerations, etc.) to achieve the best comprehensive performance.

[0043] The aerogel composite metal film thermal insulation material of this embodiment is prepared using the above-described preparation method for aerogel composite metal film thermal insulation material.

[0044] In practice, an aerogel composite metal membrane thermal insulation material is prepared through metal membrane surface treatment, fiber-metal membrane needle punching, preform molding, sol impregnation and aging, and supercritical drying. This process achieves the preparation of the aerogel composite metal membrane thermal insulation material, which possesses characteristics such as high temperature resistance, lightweight, low thermal conductivity over a wide temperature range, and high strength and toughness. It can be molded into large-size complex components and can be used as a high-temperature thermal insulation material in fields such as aviation, aerospace, nuclear power, and shipbuilding. More specifically:

[0045] 1. By utilizing the radiation shielding effect of ceramic fibers and metal films, the low thermal conductivity effect of aerogel, and a gradient structure design, this invention achieves high-temperature resistance and low thermal conductivity across a wide temperature range in aerogel insulation materials. Aerogel possesses extremely low solid and gaseous thermal conductivity, ensuring a very low overall thermal conductivity of the insulation material. Ceramic fibers have certain infrared shielding properties, which can reduce the radiative thermal conductivity of the aerogel material to a certain extent. The metal film is a low emissivity, high reflectivity material, which can effectively reflect infrared radiation electromagnetic waves while emitting very little infrared radiation electromagnetic waves, thus significantly reducing the material's radiative thermal conductivity. Simultaneously, the design incorporates a laminated structure of fibers and metal films. High-temperature resistant metal films and fibers are arranged in the high-temperature region, relatively high-temperature resistant metal films and fibers in the mid-temperature region, and relatively low-temperature resistant, low-emissivity metal films and ultrafine fibers in the low-temperature region. This gradient structure can effectively match the thermal field, minimizing the problem of high solid-state thermal conductivity in uniform insulation materials. In summary, the aerogel insulation material of this invention exhibits very low thermal conductivity across a wide temperature range.

[0046] 2. The needle-punched structure of the fiber and metal membrane, along with the inherent flexibility of the metal membrane, endows the thermal insulation material of this invention with high strength and toughness. Needling the fiber and metal membrane together forms a fiber-metal membrane preform, which is then composited with aerogel to obtain a high-strength and tough aerogel thermal insulation material. The needle-punching of the fiber and metal membrane ensures the interlayer strength of the preform. The metal membrane possesses excellent flexibility and mechanical properties, enhancing the toughness of the fiber preform. Surface treatment of the metal membrane with an oxide coating not only effectively improves its oxidation resistance and temperature resistance but also enhances the wettability of the subsequent sol-gel, forming a transition layer between the aerogel and the metal membrane, significantly increasing the bonding force between them. Simultaneously, the high-temperature supercritical drying process greatly promotes the hydroxyl condensation reaction between the gel particles and the metal membrane. These processes ensure a good bond between the aerogel, fiber, and metal membrane, guaranteeing the overall thermal insulation material possesses excellent pressure resistance and toughness.

[0047] 3. The thermal insulation material of this invention can be molded into large-sized complex components. The fibers have a high aspect ratio and flexibility, and the metal membrane has high elongation properties. The fibers and metal membrane can be laid out and needled according to the designed shape, making it easy to mold various shapes and large-sized fiber-metal membrane preforms. Thus, when combined with aerogel, it can be used to prepare large-sized complex components.

[0048] 4. Typical properties of the 1400℃-resistant aerogel composite metal membrane thermal insulation material prepared by this invention: density is 0.38 g / cm³; after heating one side at 1400℃ for 1 hour, no interfacial delamination occurs, and the thickness shrinkage rate is 0.7%; thermal conductivity at room temperature and at 1400℃ is 0.028 W / (m·K) and 0.051 W / (m·K), respectively; tensile strength is 2.8 MPa, and flexural strength is 3.5 MPa. It can be molded into components with dimensions of 1500 mm × 800 mm × 60 mm.

[0049] Example 1:

[0050] The preparation method includes the following steps:

[0051] S100, Metal Film Surface Treatment

[0052] 1) A molybdenum alloy metal film with a thickness of 10 μm was immersed in ethanol solvent at 40°C, ultrasonically cleaned for 20 min, air-dried at room temperature, and then placed in an environment at 80°C for 1 h to obtain a clean molybdenum alloy metal film.

[0053] 2) Immerse the clean molybdenum alloy metal film in 0.5% hydrochloric acid at 40℃ for 10 minutes, then immerse it in deionized water at 50℃ for 2 hours. After removing it, air dry it and place it in an oven at 150℃ for 2 hours to allow it to dry completely, thus obtaining the acid-treated molybdenum alloy metal film.

[0054] 3) The acid-treated molybdenum alloy metal film was immersed in an alumina hydrosol modification solution (the average particle size of the sol particles was 55 nm and the solid content was 20%), and then pulled out of the alumina modification solution at a uniform speed of 0.1 m / s. After drying at room temperature, it was kept at 400℃ for 8 hours to obtain the surface-treated molybdenum alloy metal film.

[0055] S200, fiber-metal membrane needle punch

[0056] A mullite fiber mesh with an average fiber diameter of 7μm, an aspect ratio of 8000, and a single-layer thickness of 2mm is laid on a tooling. Then, a surface-treated molybdenum alloy metal film is laid on the mullite fiber mesh. Alumina fiber threads (with an average fiber diameter of 8μm and a mass fraction of 8% in the overall needled part) are used to needle the mullite fiber mesh and the molybdenum alloy metal film. The laying and needle-punching of the mullite fiber mesh and the molybdenum alloy metal film are repeated layer by layer to form an integral fiber-metal film needled part with a certain shape.

[0057] S300, Precast component molding

[0058] The fiber-metal membrane needle-punched parts are formed into fiber-metal membrane preforms of a specified shape using a mold; the porosity of the preforms is 92%.

[0059] S400, Sol Impregnation and Aging

[0060] At a pressure of -0.1 MPa, alumina sol (sol with a solid content of 15%, an average particle size of 55 nm, and ethanol as the solvent) was immersed in a fiber-metal membrane preform and kept for 2 hours; then, at a pressure of 1.0 MPa, it was kept for 2 hours to obtain a fiber-metal membrane preform impregnated with sol; the fiber-metal membrane preform impregnated with sol was kept at 50°C for 18 hours to form a fiber-metal membrane preform containing gel.

[0061] S500, supercritical drying

[0062] A preform of a fiber-metal membrane containing gel was placed in an autoclave, ethanol was added, and the autoclave was kept sealed. The mixture was heated to above the critical point of ethanol and held for 12 hours. The gas inside the autoclave was then slowly released until the pressure reached zero, yielding an aerogel composite metal membrane insulation material resistant to 1400℃. The material properties are as follows: density 0.38 g / cm³. 3 After being heated to 1400℃ on one side for 1 hour, no interfacial delamination occurs, and the thickness shrinkage rate is 0.7%; the thermal conductivity at room temperature and 1400℃ is 0.028W / (m·K) and 0.051W / (m·K), respectively; the tensile strength is 2.8MPa, and the flexural strength is 3.5MPa; it can form components with a maximum size of 1500mm×800mm×60mm.

[0063] Example 2:

[0064] S100, Metal Film Surface Treatment

[0065] 1) A nickel alloy metal film with a thickness of 10 μm was immersed in ethanol solvent at 40°C, ultrasonically cleaned for 20 min, air-dried at room temperature, and then placed in an environment at 80°C for 1 h to obtain a clean nickel alloy metal film.

[0066] 2) Immerse the clean nickel alloy metal film in 0.5% hydrochloric acid at 40℃ for 10 minutes, then immerse it in deionized water at 50℃ for 2 hours. After removing it, air dry it and place it in an oven at 150℃ for 2 hours to allow it to dry completely, thus obtaining the acid-treated nickel alloy metal film.

[0067] 3) The acid-treated nickel alloy metal film was immersed in a silica hydrosol modification solution (the average particle size of the hydrosol was 30 nm and the solid content was 20%), and then pulled out of the silica modification solution at a uniform speed of 0.1 m / s. After drying at room temperature, it was kept at 400℃ for 8 hours to obtain the surface-treated nickel alloy metal film.

[0068] S200, fiber-metal membrane needle punch

[0069] Zirconia fiber mesh with an average fiber diameter of 3μm, an aspect ratio of 8000, and a single layer thickness of 2mm is laid on a tooling. Then, a surface-treated nickel alloy metal film is laid on the zirconia fiber mesh. Quartz fiber thread (with an average fiber diameter of 8μm and a mass fraction of 8% in the overall needled part) is used to needle the zirconia fiber mesh and nickel alloy metal film. The laying and needleding of zirconia fiber mesh and nickel alloy metal film are repeated layer by layer to form an integral fiber-metal film needled part with a certain shape.

[0070] S300, Precast component molding

[0071] The fiber-metal membrane needle-punched parts are formed into fiber-metal membrane preforms of a specified shape using a mold; the porosity of the preforms is 92%.

[0072] S400, Sol Impregnation and Aging

[0073] At a pressure of -0.1 MPa, silica sol (sol with a solid content of 15%, an average particle size of 30 nm, and isopropanol as the solvent) was immersed in a fiber-metal membrane preform and kept for 2 hours; then, at a pressure of 1.2 MPa, it was kept for 2 hours to obtain a fiber-metal membrane preform impregnated with sol; the fiber-metal membrane preform impregnated with sol was kept at 50 °C for 18 hours to form a fiber-metal membrane preform containing gel.

[0074] S500, supercritical drying

[0075] A preform of a gel-containing fiber-metal membrane was placed in an autoclave, isopropanol was added, and the autoclave was kept sealed. The mixture was heated above the critical point of isopropanol and held for 8 hours. The gas inside the autoclave was then slowly released until the pressure reached zero, yielding an aerogel composite metal membrane insulation material resistant to 1200℃. The material properties are as follows: density 0.37 g / cm³. 3 After being heated to 1200℃ on one side for 1 hour, no interfacial delamination occurs, and the thickness shrinkage rate is 0.5%; the thermal conductivity at room temperature and 1200℃ is 0.027W / (m·K) and 0.038W / (m·K), respectively; the tensile strength is 2.9MPa, and the flexural strength is 3.7MPa; it can be molded into components with a maximum size of 1500mm×800mm×60mm.

[0076] Example 3:

[0077] S100, Metal Film Surface Treatment

[0078] 1) Immerse a stainless steel metal film with a thickness of 5μm in ethanol solvent at 40℃, clean it with ultrasonic cleaning for 20min, air dry it at room temperature, and then keep it in an environment of 80℃ for 1h to obtain a clean stainless steel metal film.

[0079] 2) Immerse the clean stainless steel metal film in 0.5% hydrochloric acid at 40℃ for 10 minutes, then immerse it in deionized water at 50℃ for 2 hours. After removing it, air dry it and place it in an oven at 150℃ for 2 hours to allow it to dry completely, thus obtaining the acid-treated stainless steel metal film.

[0080] 3) The acid-treated stainless steel metal film was immersed in a silica hydrosol modification solution (the average particle size of the hydrosol was 10 nm and the solid content was 20%), and then pulled out of the silica modification solution at a uniform speed of 0.1 m / s. After drying at room temperature, it was kept at 400℃ for 8 hours to obtain the surface-treated stainless steel metal film.

[0081] S200, fiber-metal membrane needle punch

[0082] A quartz fiber mesh with an average fiber diameter of 2μm, an aspect ratio of 8000, and a single-layer thickness of 2mm is laid on a tooling. Then, a surface-treated stainless steel metal film is laid on the quartz fiber mesh. Quartz fiber threads (with an average fiber diameter of 8μm and a mass fraction of 8% in the overall needled part) are used to needle the quartz fiber mesh and stainless steel metal film. The laying and needle-punching of the quartz fiber mesh and stainless steel metal film are repeated layer by layer to form an integral fiber-metal film needled part of a certain shape.

[0083] like Figure 1 As shown, fibers are displayed. The physical form of the metal film needle-punched component shows a complete structure and a smooth surface. The metal film and quartz fiber mesh are tightly bonded together through needle punching, with no obvious peeling or wrinkles. A scale indicates the fiber... The metal film needle-punched part has a certain dimensional accuracy, proving that step S200 (layout) in Example 3 has certain dimensional accuracy. The needle punching process can stably produce preforms with uniform structures, providing an ideal framework for subsequent sol-gel impregnation.

[0084] S300, Precast component molding

[0085] The fiber-metal membrane needle-punched parts are formed into fiber-metal membrane preforms of a specified shape using a mold; the porosity of the preforms is 94%.

[0086] S400, Sol Impregnation and Aging

[0087] At a pressure of -0.09 MPa, silica sol (sol with a solid content of 15%, an average particle size of 10 nm, and n-butanol as the solvent) was immersed in a fiber-metal membrane preform and kept for 2 hours; then, at a pressure of 1.3 MPa, it was kept for 2 hours to obtain a fiber-metal membrane preform impregnated with sol; the fiber-metal membrane preform impregnated with sol was kept at 50°C for 18 hours to form a fiber-metal membrane preform containing gel.

[0088] S500, supercritical drying

[0089] A fiber-metal membrane preform containing gel is placed in an autoclave, n-butanol is added and the autoclave is kept sealed. The autoclave is heated to above the critical point of n-butanol and held for 8 hours. The gas in the autoclave is slowly discharged until the pressure is 0, thus obtaining an 800℃ resistant aerogel composite metal membrane insulation material.

[0090] like Figure 2 As shown, the aerogel composite metal membrane insulation material is dense overall, without visible cracks or collapses, with a smooth surface and good bonding with the metal membrane interface. The ruler indicates that the material molding dimensions are accurate, confirming step S300. S500 (Precast) Sol impregnation (Supercritical drying): The silica sol fully fills the pores of the needled part (porosity 94%), and after aging and supercritical drying, it forms a complete aerogel. Metal-film composite, with no structural damage.

[0091] The material properties are as follows: density is 0.32 g / cm³. 3 After being heated to 800℃ on one side for 1 hour, no interfacial delamination occurs, and the thickness shrinkage rate is 0.2%; the thermal conductivity at room temperature and 800℃ is 0.022W / (m·K) and 0.029W / (m·K), respectively; the tensile strength is 3.2MPa, and the flexural strength is 4.0MPa; it can form components with a maximum size of 1500mm×800mm×60mm.

[0092] Example 4:

[0093] S100, Metal Film Surface Treatment

[0094] 1) An aluminum alloy metal film with a thickness of 5μm was immersed in ethanol solvent at 40℃, ultrasonically cleaned for 20min, air-dried at room temperature, and then placed in an environment at 80℃ for 1h to obtain a clean aluminum alloy metal film.

[0095] 2) Immerse the clean aluminum alloy metal film in 0.5% hydrochloric acid at 40℃ for 10 minutes, then immerse it in deionized water at 50℃ for 2 hours. After removing it, air dry it and place it in an oven at 150℃ for 2 hours to allow it to dry completely, thus obtaining the acid-treated aluminum alloy metal film.

[0096] 3) The acid-treated aluminum alloy metal film is immersed in a silica hydrosol modification solution (the average particle size of the hydrosol is 5 nm and the solid content is 20%), and then pulled out from the silica modification solution at a uniform speed of 0.1 m / s. After drying at room temperature, it is kept at 400℃ for 8 hours to obtain the surface-treated aluminum alloy metal film.

[0097] S200, fiber-metal membrane needle punch

[0098] Rock wool fiber mesh with an average fiber diameter of 1μm, an aspect ratio of 12000, and a single layer thickness of 2mm is laid on a tooling. Then, a surface-treated aluminum alloy metal film is laid on the rock wool fiber mesh. Rock wool fiber thread (with an average fiber diameter of 8μm and a mass fraction of 8% in the overall needled part) is used to needle the rock wool fiber mesh and aluminum alloy metal film. The laying and needle-punching of rock wool fiber mesh and aluminum alloy metal film are repeated layer by layer to form an integral fiber-metal film needled part of a certain shape.

[0099] S300, Precast component molding

[0100] The fiber-metal membrane needle-punched parts are formed into fiber-metal membrane preforms of a specified shape using a mold; the porosity of the preforms is 96%.

[0101] S400, Sol Impregnation and Aging

[0102] At a pressure of -0.09 MPa, silica sol (sol with a solid content of 10%, an average particle size of 5 nm, and ethanol as the solvent) was immersed in a fiber-metal membrane preform and kept for 2 hours; then, at a pressure of 1.5 MPa, it was kept for 2 hours to obtain a fiber-metal membrane preform impregnated with sol; the fiber-metal membrane preform impregnated with sol was kept at 40°C for 18 hours to form a fiber-metal membrane preform containing gel.

[0103] S500, supercritical drying

[0104] A preform of a gel-containing fiber-metal membrane was placed in an autoclave, ethanol was added, and the autoclave was kept sealed. The mixture was heated to above the critical point of ethanol and held for 6 hours. The gas inside the autoclave was then slowly released until the pressure reached zero, yielding an aerogel composite metal membrane insulation material resistant to 600℃. The material properties are as follows: density 0.28 g / cm³. 3 After being heated to 600℃ on one side for 1 hour, no interfacial delamination occurs, and the thickness shrinkage rate is 0.1%; the thermal conductivity at room temperature and 600℃ is 0.021W / (m·K) and 0.022W / (m·K), respectively; the tensile strength is 3.4MPa, and the flexural strength is 4.6MPa; it can be molded into components with a maximum size of 1500mm×800mm×60mm.

[0105] Comparative Example 1:

[0106] The difference from Example 1 is that the molybdenum alloy metal film used in step S100 has a thickness of 100 μm and the aerogel composite metal film insulation material has a density of 0.42 g / cm³. 3The thermal conductivity at room temperature and 1400℃ is 0.032 W / (m·K) and 0.063 W / (m·K), respectively. This indicates that when the thickness of the metal film is large, the material density increases, which in turn increases the solid-state thermal conduction of the material, resulting in a significant increase in thermal conductivity.

[0107] Comparative Example 2:

[0108] The difference from Example 1 is that step S100 does not use step 3), i.e., the modification liquid treatment is not performed. The aerogel composite metal membrane insulation material has a tensile strength of 2.1 MPa and a flexural strength of 2.8 MPa. This indicates that if the metal membrane is not modified, the interfacial bonding force with the aerogel is reduced, thereby decreasing the mechanical properties of the material.

[0109] Comparative Example 3:

[0110] The difference from Example 1 is that the mullite fiber in step S200 has an aspect ratio of 2000, a tensile strength of 1.9 MPa, and a flexural strength of 2.2 MPa. This indicates that when the fiber aspect ratio is small, its reinforcing effect decreases significantly, and the mechanical properties of the material are reduced.

[0111] Comparative Example 4:

[0112] The difference from Example 1 is that the average particle size of the alumina sol particles in step S400 is 100 nm, and the thermal conductivity of the aerogel composite metal film insulation material at room temperature and 1400℃ is 0.031 W / (m·K) and 0.059 W / (m·K), respectively; the tensile strength is 2.2 MPa, and the flexural strength is 2.8 MPa. This indicates that the average particle size of the alumina sol particles is relatively large, resulting in coarser aerogel skeleton particles, increased solid-state thermal conductivity, and decreased strength, thus leading to a significant increase in the thermal conductivity and a significant decrease in the mechanical properties of the material.

[0113] Comparative Example 5:

[0114] The difference from Example 1 is that only atmospheric pressure impregnation is used in step S400. The density of the aerogel composite metal membrane insulation material is 0.33 g / cm³. 3 The thermal conductivity at room temperature and 1400℃ is 0.033 W / (m·K) and 0.064 W / (m·K), respectively; the tensile strength is 1.7 MPa and the flexural strength is 2.0 MPa. This indicates that the atmospheric pressure impregnation method is insufficient to fully impregnate the alumina sol into the preform, resulting in a significantly low aerogel content in the material, thus leading to lower material density, higher thermal conductivity, and lower mechanical properties.

[0115] Matters not covered in this invention are common knowledge.

[0116] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0117] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

[0118] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing an aerogel composite metal film thermal insulation material, characterized in that, Includes the following steps: S100, metal film surface treatment, through cleaning, acid etching and coating of modified layer, removes contaminants on the surface of metal film and forms a stable, highly adhesive inorganic protective layer; The surface treatment of the metal film in step S100 is specifically as follows: S101, the metal film is immersed in a solvent at 30℃~60℃, ultrasonically cleaned for 5min~30min, air-dried at room temperature, and then placed in an environment at 60℃~100℃ for 0.5h~2h to obtain a clean metal film; S102, the clean metal film is immersed in dilute acid at 20℃~60℃ for 3min~60min, then removed and immersed in deionized water at 40℃~90℃ for 1h~4h, then removed and air-dried, and placed in an oven at 105℃~200℃ for 1h~4h to fully dry it to obtain an acid-treated metal film; S103, the acid-treated metal film is immersed in a modification solution and pulled out of the modification solution at a uniform speed of 0.01m / s~0.2m / s, air-dried at room temperature, and then placed in an environment at 300℃~600℃ for 4h~12h to obtain a surface-treated metal film; The thickness of the metal film ranges from 2 μm to 50 μm; S200, fiber-metal membrane needle punching, enhances the bonding force between the metal membrane and the fiber mesh by layering and needle punching composite of fiber and metal membrane, resulting in an integrated fiber-metal membrane needle punch part that combines the high temperature resistance of fiber with the flexibility of metal. S300, Preform Forming: The integrated fiber-metal membrane needled part is formed by mold and the porosity is controlled to prepare a fiber-metal membrane preform with a specified shape and pore structure. S400, sol impregnation and aging, through staged pressure control, achieve efficient penetration and filling of sol in fiber-metal membrane preforms, and complete the transformation of sol to gel in the low-temperature aging stage, thereby constructing a uniform and stable continuous phase of nanoparticles in fiber-metal membrane preforms, forming a fiber-metal membrane preform containing gel. The preform forming in step S400 specifically involves: immersing the fiber-metal membrane preform in a sol at a pressure of -0.1 MPa to -0.09 MPa for 0.5 h to 3 h; then immersing it in the sol at a pressure of 0.5 MPa to 2.0 MPa for 0.5 h to 3 h to obtain the sol-impregnated fiber-metal membrane preform; and then immersing the sol-impregnated fiber-metal membrane preform in a temperature of 40 °C to 70 °C for 12 h to 24 h to form a gel-containing fiber-metal membrane preform. The average particle size of the sol is 3 nm to 60 nm. S500 supercritical drying is used for fiber-metal membrane preforms containing gel. It utilizes the property that alcohol fluids have no gas-liquid interfacial surface tension in the supercritical state to completely remove the solvent without destroying the gel network structure, thereby preparing aerogel composite metal membrane thermal insulation material.

2. The method of claim 1, wherein the aerogel composite metal film insulation material is prepared by the steps of: The solvent in step S101 is any one of acetone, ethanol, and isopropanol.

3. The method of claim 1, wherein the aerogel composite metal film insulation material is prepared by the steps of: The dilute acid in step S102 is any one of hydrochloric acid, nitric acid, or sulfuric acid aqueous solution, with a mass fraction of 0.2% to 2%.

4. The method of claim 1, wherein the aerogel composite metal film insulation material is prepared by the steps of: The fiber-metal membrane needle punching in step S200 is specifically as follows: The fiber mesh is laid on the tooling, and then the surface-treated metal film is laid on the fiber mesh. The fiber mesh and the metal film are needle-punched together with fiber thread. This process involves repeatedly laying and needle-punching the fiber mesh and metal film layer by layer to form a fiber-metal film needle-punched part.

5. The method of claim 4, wherein the aerogel composite metal film insulation material is prepared by the steps of: The fiber mesh is made of any one of rock wool, glass fiber, quartz fiber, aluminum silicate fiber, high silica fiber, zirconium oxide fiber, alumina fiber, or mullite fiber. The average diameter of the fiber is 0.5μm to 10μm, the aspect ratio is 5000 to 20000, and the thickness of the fiber mesh is 0.5mm to 5mm. The fiber yarn can be any one of rock wool, glass fiber, quartz fiber, high silica fiber, or alumina fiber, with an average fiber diameter of 5μm to 12μm. The mass fraction of fiber threads in the overall fiber-metal film needled part is 5% to 12%.

6. The method of claim 1, wherein the aerogel composite metal film insulation material is prepared by the steps of: The preform forming in step S300 is specifically as follows: The fiber-metal membrane needled parts are formed into fiber-metal membrane preforms of a specified shape using a mold, and the porosity of the fiber-metal membrane preforms is between 89% and 97%.

7. The method of claim 1, wherein the aerogel composite metal film insulation material is prepared by the steps of: The sol is any one of silica sol, zirconium oxide sol, or alumina sol, and the solid content of the sol is 8% to 25%.

8. The method for preparing the aerogel composite metal film thermal insulation material according to claim 7, characterized in that, The solvent used in the sol is any one of ethanol, isopropanol, n-propanol, n-butanol, sec-butanol, and tert-butanol.

9. The method of claim 1, wherein the aerogel composite metal film insulation material is prepared by the steps of: The supercritical drying in step S500 is specifically as follows: A fiber-metal membrane preform containing gel is placed in an autoclave, an alcohol is added and the autoclave is kept sealed, and the autoclave is heated to above the critical point of the alcohol and kept for 8 to 16 hours. The gas in the autoclave is slowly discharged until the pressure is 0, thus obtaining an aerogel composite metal membrane insulation material.

10. The method for preparing the aerogel composite metal film thermal insulation material according to claim 9, characterized in that, The alcohols are any one of ethanol, isopropanol, n-propanol, n-butanol, sec-butanol, and tert-butanol.

11. The method of claim 1-10, wherein the aerogel composite metal film insulation is prepared by the steps of: The metal film in step S100 is any one of aluminum alloy, titanium alloy, copper, stainless steel, silver, gold, iron-chromium-aluminum, nickel alloy, and molybdenum alloy.

12. An aerogel composite metal film thermal barrier material characterized by, The aerogel composite metal film thermal insulation material is prepared using any one of claims 1 to 11.

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