Thermal sound-absorbing structure integrated composite material and preparation method thereof

Abstract

The application belongs to the field of composite materials, and particularly relates to a heat-proof and sound-absorbing structure integrated composite material with low manufacturing cost, heat-proof effect meeting use requirements and weight reduction requirements and a preparation method thereof. The heat-proof and sound-absorbing structure integrated composite material comprises an external surface layer and an internal surface layer, a sound-absorbing and heat-proof layer is arranged between the external surface layer and the internal surface layer, the external surface layer comprises a surface layer and at least one inner layer, the surface layer is made of polysilazane modified silicium-containing arylacetylene resin, oxide powder and quartz fiber, the inner layer is made of boron phenolic resin, oxide powder and quartz fiber, the content of the oxide powder in the inner layer is less than that in the surface layer, the integrated composite material has heat-proof and sound-absorbing capabilities, meets the requirements of multiple functions, has low manufacturing cost and good structural strength.

Description

Technical Field

[0001] This invention belongs to the field of composite materials, and specifically relates to an integrated heat-insulating and sound-absorbing composite material with low manufacturing cost, heat-insulating effect that meets the requirements of use and weight reduction, and its preparation method. Background Technology

[0002] Over the past two decades, major aerospace powers worldwide have conducted a series of research projects focusing on hypersonic space transportation systems, hypersonic missiles, and hypersonic aircraft. Hypersonic technology will play a crucial strategic role in future military, political, and economic affairs, becoming a powerful tool for nations to gain air and space superiority. Thermal protection systems, as a key subsystem of hypersonic vehicles, have become a focus of research in this field. High-speed airflow-driven vehicles will experience aerodynamic heating on their surfaces, with surface temperature increasing proportionally to the square of the Mach number. When a vehicle flies at Mach 10 for an extended period in the atmosphere, the temperature of its large windward surface will exceed 1500°C.

[0003] Currently, near-space vehicles, space shuttles, and spaceplanes, among other hypersonic weapons and equipment, all employ rigid heat-resistant tile systems as large-area thermal protection materials on their windward surfaces. A rigid heat-resistant tile system consists of an outer coating, heat-resistant tiles, strain gauges, and room-temperature curing silicone. Rigid heat-resistant tiles have poor toughness and cannot withstand deformation; strain gauges are necessary to connect the heat-resistant tiles to the main structure to eliminate deformation transmission. While strain gauges largely solve the brittleness problem of rigid heat-resistant tiles, they increase structural complexity and significantly reduce structural stability, especially during takeoff and landing when they are highly susceptible to detachment due to vibration. Furthermore, the thermal expansion coefficients of the heat-resistant tile material differ greatly from those of the airframe material, resulting in significant temperature differences during spacecraft loading. Appropriate gaps must be maintained between the heat-resistant tiles, as these gaps can easily create thermal short-circuit paths, affecting the overall heat protection effect. Rigid heat-resistant tiles also suffer from drawbacks such as water absorption, shrinkage at high temperatures, and difficulty in maintenance, severely limiting their application in advanced aerospace weapons and equipment.

[0004] Existing technologies for multi-layer integrated thermal protection materials mainly focus on metal panels. There are also multi-layer thermal protection materials using ceramic panels, but these ceramic panel thermal protection materials add ceramic precursors to the top panel, using the same amount of ceramic precursors throughout the entire top panel, which significantly increases the weight of the thermal protection material. Although the thermal protection performance meets the requirements, the increased weight brings other problems. Furthermore, existing thermal anti-slip materials only have thermal protection capabilities. If sound absorption is also required, a layer of sound-absorbing material is usually combined after the thermal protection material. The connection strength and reliability of the joint surface between the two have significant potential risks. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention designs an integrated composite material with heat protection and sound absorption functions, and its preparation method.

[0006] The technical solution of the present invention is as follows:

[0007] An integrated heat-resistant and sound-absorbing composite material is characterized by comprising an outer surface layer and an inner surface layer, with a sound-absorbing and heat-insulating layer disposed between the outer surface layer and the inner surface layer. The outer surface layer comprises a top layer and at least one inner layer. The top layer is made of polysilazane-modified silane-containing aromatic resin, oxide powder, and quartz fiber. The inner layer is made of boron phenolic resin, oxide powder, and quartz fiber. The oxide powder content of the inner layer is less than that of the top layer.

[0008] Furthermore, the outer surface layer comprises a surface layer and at least two inner layers, and the content of the oxide powder decreases progressively from the surface layer to the inner layers.

[0009] Furthermore, the sound-absorbing and heat-insulating layer is composed of multiple box-shaped components stacked one on top of the other. Each box-shaped component includes an aerogel core and a prepreg shell covering the aerogel core around its perimeter and bottom. The aerogel core is processed into a wedge-shaped sound-absorbing structure, and the box-shaped components of adjacent layers are staggered.

[0010] Furthermore, the wedge-shaped sound-absorbing structures in the adjacent layers are also staggered.

[0011] Furthermore, the prepreg shell is formed by laying and pre-curing a fiber matrix and a boron phenolic resin prepreg, wherein the fiber matrix is ​​any one of glass fiber, basalt fiber or alumina fiber.

[0012] Furthermore, the inner surface layer is a carbon fiber composite material, specifically a prepreg of carbon fiber and bismaleimide resin.

[0013] Furthermore, the oxide powder is any one of zirconium oxide, magnesium oxide, or beryllium oxide.

[0014] A method for preparing an integrated heat-resistant and sound-absorbing composite material, characterized in that the method comprises:

[0015] Step S100, preparation of the outer surface layer, includes preparation of a surface prepreg and preparation of an inner prepreg. The preparation of the surface prepreg includes impregnating quartz fibers in a polysilazane-modified silane-containing aromatic resin mixed with oxide powder to obtain the surface prepreg. The preparation of the inner prepreg includes impregnating quartz fibers in a boron phenolic resin mixed with oxide powder to obtain the inner prepreg. The surface prepreg and at least one inner prepreg are stacked together to obtain the outer surface layer. The oxide powder content in the inner prepreg is greater than the oxide powder content in the surface prepreg.

[0016] Step S110, preparation of sound-absorbing and heat-insulating layer, wherein the sound-absorbing and heat-insulating layer is composed of multiple box-shaped components stacked in upper and lower layers, wherein the box-shaped components include an aerogel core and a prepreg shell covering the aerogel core around and on the bottom surface, and a wedge sound-absorbing structure is processed on the aerogel core.

[0017] Step S120, preparation of the inner surface layer, wherein the preparation of the inner surface layer includes laying it up using a prepreg of carbon fiber and bismaleimide resin;

[0018] Step S130: The inner surface layer, the sound-absorbing and heat-insulating layer and the outer surface layer are laid in sequence and co-cured to obtain an integrated composite material with heat-insulating and sound-absorbing structure.

[0019] Furthermore, the outer surface layer in step S100 comprises a surface prepreg and at least two inner prepregs stacked together, and the content of oxide powder in the inner prepreg gradually decreases.

[0020] Furthermore, in step S110, the upper and lower box-shaped components are misaligned, and the wedge-shaped sound-absorbing structure on the aerogel core is also misaligned.

[0021] In summary, the present invention has the following beneficial effects:

[0022] 1. This invention improves the heat protection material for spacecraft. First, the structure of the heat protection material is improved by adopting a multi-layer composite integral molding structure, specifically a three-layer structure design: an outer surface layer, a sound-absorbing and heat-insulating layer, and an inner surface layer. The outer surface layer is made of a material with good heat resistance, which can withstand the high temperatures during spacecraft flight. The sound-absorbing and heat-insulating layer uses heat-insulating materials and sound-absorbing structures. On the one hand, it can play a role in heat insulation, preventing heat from the outer surface layer from being transferred inward. On the other hand, it has a sound-absorbing function. The inner surface layer is made of carbon fiber, which has good structural strength and meets the strength requirements after the composite material is formed.

[0023] 2. This invention further improves the composite material and the structure of the outer surface layer. The outer surface layer adopts a multi-layer integrated molding method. Specifically, the outer surface layer is made of polysilazane-modified silane-containing aromatic resin, quartz fiber, and oxide powder, which has strong erosion resistance and high thermal conductivity, giving the surface layer strong ablation resistance. Furthermore, the inner layer is made of quartz fiber, oxide powder, and boron phenolic resin. The inner layer has lower erosion resistance than the outer layer, but lower thermal conductivity, preventing heat transfer inward. At the same time, the oxide powder content in the inner layer is lower than that in the outer layer, further reducing the weight of the integrated composite material and meeting the weight reduction requirements. Furthermore, the inner layer of this invention can be made of multiple stacked inner layers, but the oxide powder content of each inner layer decreases sequentially from the one closest to the surface layer. The addition of multiple inner layers not only improves the heat insulation capacity but also effectively controls the weight of the product.

[0024] 3. This invention also improves the structure of the sound-absorbing and heat-insulating layer. The sound-absorbing and heat-insulating layer is made of multiple box-shaped parts stacked together, and the box-shaped parts of adjacent layers are staggered. When multiple box-shaped parts are stacked, the prepreg shells of adjacent box-shaped parts are connected. If there is no staggered arrangement, the prepreg shell will penetrate the cross section of the integrated composite material, and the heat of the outer surface layer will be quickly transferred to the inner surface layer through the prepreg shell. The staggered arrangement can avoid the rapid transfer of heat through the prepreg shell. Furthermore, the staggered arrangement of the box-shaped parts also makes the wedge sound-absorbing structure of the aerogel processing staggered, which has a better sound absorption effect. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the present invention;

[0026] Figure 2 This is a schematic diagram of the outer surface layer;

[0027] Figure 3 This is a structural schematic diagram of a box-shaped component;

[0028] In the figure, 1 is the outer surface layer, 2 is the inner surface layer, 10 is the surface layer, 11 is the inner layer, 3 is the sound-absorbing and heat-insulating layer, 30 is the box-shaped component, 300 is the aerogel core, and 301 is the prepreg shell. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0030] It should be noted that when a component is referred to as being "set on" or "fixed to" another component, it can be directly on the other component or there may be an intermediate component. When a component is referred to as being "fixed to" another component, or "fixedly connected" to another component, the fixing method can be detachable or non-detachable. When a component is considered to be "connected" or "rotatably connected" to another component, it can be directly connected to the other component or there may be an intermediate component. The terms "vertical," "horizontal," "left," "right," "upper," "lower," and similar expressions used are for illustrative purposes only and do not represent the only possible implementation.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0032] In this invention, terms such as "first," "second," and "third" are used not to represent specific quantities or orders, but merely to distinguish names. Example

[0033] See Figures 1 to 3 As shown, the integrated heat-resistant and sound-absorbing composite material is characterized by comprising an outer surface layer 1 and an inner surface layer 2, with a sound-absorbing and heat-insulating layer 3 disposed between the outer surface layer 1 and the inner surface layer 2. The outer surface layer 1 comprises a surface layer 10 and at least one inner layer 11. The surface layer 10 is made of polysilazane-modified silane-containing aromatic resin, oxide powder, and quartz fiber. The inner layer 11 is made of boron phenolic resin, oxide powder, and quartz fiber. The oxide powder content of the inner layer is less than that of the surface layer.

[0034] This invention improves the structure of thermal protection materials. The integrated heat-resistant and sound-absorbing composite material of this invention is integrally molded from multiple functional materials. The outer surface layer is a heat-resistant layer, and the inner surface layer is a carbon fiber structural reinforcement layer, providing structural strength to the entire material. Simultaneously, a sound-absorbing and heat-insulating layer is integrally co-cured between the outer and inner surface layers. Firstly, this invention achieves the integration of heat-resistant and sound-absorbing functional materials, resulting in good overall material integrity and avoiding the poor connection strength and reliability issues present in the combination of two materials in existing technologies. Secondly, this invention further improves the composition of the outer surface layer, which is composed of multiple composite materials, specifically divided into a surface layer and an inner layer. The outer layer is made of polysilazane-modified silane-containing aromatic resin, quartz fiber, and oxide powder, enabling it to withstand high ablation temperatures. The inner layer is made of quartz fiber, oxide powder, and boron phenolic resin. The thermal conductivity of the inner layer material is lower than that of the outer layer material. At the same time, the oxide powder content in the inner layer material is less than that in the outer layer. While ensuring heat protection requirements, the weight of the outer surface layer can be adjusted by regulating the oxide powder content, thus meeting the lightweight requirements of the integrated heat-resistant and sound-absorbing composite material for the application environment.

[0035] Based on the foregoing, this embodiment further defines the outer surface layer, which includes a surface layer and at least two inner layers. The content of oxide powder decreases layer by layer from the surface layer to the inner layers. In this embodiment, there is one surface layer and three inner layers. Starting from the surface layer, the proportion of oxide powder is 9%wt. The proportions of oxide powder in the three inner layers are 6%wt, 3%wt, and 0%wt, respectively. The content of oxide powder in the inner layers can eventually be reduced to zero. By adjusting the content of oxide powder, the quality of the integrated composite material is controlled, meeting the lightweight requirements of the application scenario and reducing the manufacturing cost of the product. Compared with the prior art where the oxide powder content in the outer surface layer is uniform, this invention has a higher cost performance.

[0036] Furthermore, in this embodiment, the sound-absorbing and heat-insulating layer 3 is composed of multiple box-shaped components 30 stacked layer by layer. Each box-shaped component 30 includes an aerogel core 300 and a prepreg shell 301 covering the aerogel core around its perimeter and bottom. The aerogel core is processed into a wedge-shaped sound-absorbing structure. The box-shaped components of adjacent layers are staggered. This invention provides a sound-absorbing and heat-insulating layer between the outer and inner surface layers. On the one hand, it has a heat-insulating function, utilizing the low thermal conductivity of the material itself to prevent heat from spreading to the inner surface layer. On the other hand, by processing the aerogel into a wedge-shaped sound-absorbing structure, it utilizes the characteristics of the aerogel core itself and its structure to absorb sound, reducing the impact of sound on downstream equipment.

[0037] Furthermore, the adjacent wedge sound-absorbing structures are also staggered. The wedge sound-absorbing structures are staggered, with the tip of the lower wedge sound-absorbing structure corresponding to the valley of the upper wedge sound-absorbing structure. This allows for further wedge sound absorption of the sound transmitted from the valley, thus improving the sound absorption effect.

[0038] The prepreg shell of the box-shaped component is defined here. The prepreg shell 301 is made of fiber matrix and boron phenolic resin prepreg laid and pre-cured. The fiber matrix can be any one of glass fiber, basalt fiber or alumina fiber. The prepreg shell is made of fiber boron phenolic resin prepreg laid in a staggered manner, so that there is no straight heat conduction path formed by the prepreg shell between the outer surface layer and the inner surface layer. Instead, the heat conduction path formed by the staggered arrangement is formed from the side wall of the prepreg shell to the bottom surface and then to the side wall of the next box-shaped component to the bottom surface of the prepreg shell. This extends the length of the heat conduction path formed by the prepreg shell and avoids the problem of heat transfer too quickly or too concentrated.

[0039] The inner surface layer 2 is a carbon fiber composite material, specifically a prepreg of carbon fiber and bismaleimide resin. Since the inner surface layer has a relatively low requirement for heat protection, a prepreg of carbon fiber and bismaleimide resin with better structural strength is used for processing, which ensures the structural strength of the composite material after integral molding and meets the strength requirements of the application scenario.

[0040] In the above embodiments, the oxide powder is any one of zirconium oxide, magnesium oxide, or beryllium oxide.

[0041] A method for preparing an integrated heat-resistant and sound-absorbing composite material, characterized in that the method comprises:

[0042] Step S100, preparation of the outer surface layer, includes preparation of a surface prepreg and preparation of an inner prepreg. The preparation of the surface prepreg includes impregnating quartz fibers in a polysilazane-modified silane-containing aromatic resin mixed with oxide powder to obtain the surface prepreg. The preparation of the inner prepreg includes impregnating quartz fibers in a boron phenolic resin mixed with oxide powder to obtain the inner prepreg. The surface prepreg and at least one inner prepreg are stacked together to obtain the outer surface layer. The oxide powder content in the inner prepreg is greater than the oxide powder content in the surface prepreg.

[0043] Step S110, preparation of sound-absorbing and heat-insulating layer, wherein the sound-absorbing and heat-insulating layer is composed of multiple box-shaped components stacked in upper and lower layers, wherein the box-shaped components include an aerogel core and a prepreg shell covering the aerogel core around and on the bottom surface, and a wedge sound-absorbing structure is processed on the aerogel core.

[0044] Step S120, preparation of the inner surface layer, wherein the preparation of the inner surface layer includes laying it up using a prepreg of carbon fiber and bismaleimide resin;

[0045] Step S130: The inner surface layer, the sound-absorbing and heat-insulating layer and the outer surface layer are laid in sequence and co-cured to obtain an integrated composite material with heat-insulating and sound-absorbing structure.

[0046] The preparation method described in this invention first involves segmented processing, where the fiber and resin prepregs used for the outer surface layer, inner surface layer, and sound-absorbing and heat-insulating layer are pre-processed separately. Finally, the outer surface layer, sound-absorbing and heat-insulating layer, and inner surface layer are laid and stacked according to the designed stacking method, and then co-cured into a single integral molding process to finally obtain a composite material with integrated heat-insulating and sound-absorbing capabilities.

[0047] Furthermore, the outer surface layer in step S100 comprises a surface prepreg and at least two inner prepregs stacked together, with the oxide powder content in the inner prepregs gradually decreasing. Here, the structure of the outer surface layer is further defined. The number of surface and inner layers included in the outer surface layer is determined according to the heat protection requirements, and the weight of the composite material is reduced by limiting the oxide content of each layer, ultimately achieving both heat protection and weight reduction requirements.

[0048] Furthermore, in step S110, the upper and lower box-shaped components are staggered, and the wedge-shaped sound-absorbing structures on the aerogel core are also staggered. This staggered structure avoids the formation of a straight heat conduction path between the outer and inner surfaces by the prepreg shell, thus extending the length of the heat conduction path formed by the prepreg shell and preventing the problem of heat transfer or concentration being too fast. On the other hand, it also makes the wedge-shaped sound-absorbing structures staggered, thereby improving the sound absorption effect of the wedge-shaped sound-absorbing structures.

[0049] In summary, the present invention has the following beneficial effects:

[0050] 1. This invention improves the heat protection material for spacecraft. First, the structure of the heat protection material is improved by adopting a multi-layer composite integral molding structure, specifically a three-layer structure design: an outer surface layer, a sound-absorbing and heat-insulating layer, and an inner surface layer. The outer surface layer is made of a material with good heat resistance, which can withstand the high temperatures during spacecraft flight. The sound-absorbing and heat-insulating layer uses heat-insulating materials and sound-absorbing structures. On the one hand, it can play a role in heat insulation, preventing heat from the outer surface layer from being transferred inward. On the other hand, it has a sound-absorbing function. The inner surface layer is made of carbon fiber, which has good structural strength and meets the strength requirements after the composite material is formed.

[0051] 2. This invention further improves the composite material and the structure of the outer surface layer. The outer surface layer adopts a multi-layer integrated molding method. Specifically, the outer surface layer is made of polysilazane-modified silane-containing aromatic resin, quartz fiber, and oxide powder, which has strong erosion resistance and high thermal conductivity, giving the surface layer strong ablation resistance. Furthermore, the inner layer is made of quartz fiber, oxide powder, and boron phenolic resin. The inner layer has lower erosion resistance than the outer layer, but lower thermal conductivity, preventing heat transfer inward. At the same time, the oxide powder content in the inner layer is lower than that in the outer layer, further reducing the weight of the integrated composite material and meeting the weight reduction requirements. Furthermore, the inner layer of this invention can be made of multiple stacked inner layers, but the oxide powder content of each inner layer decreases sequentially from the one closest to the surface layer. The addition of multiple inner layers not only improves the heat insulation capacity but also effectively controls the weight of the product.

[0052] 3. This invention also improves the structure of the sound-absorbing and heat-insulating layer. The sound-absorbing and heat-insulating layer is made of multiple box-shaped parts stacked together, and the box-shaped parts of adjacent layers are staggered. When multiple box-shaped parts are stacked, the prepreg shells of adjacent box-shaped parts are connected. If there is no staggered arrangement, the prepreg shell will penetrate the cross section of the integrated composite material, and the heat of the outer surface layer will be quickly transferred to the inner surface layer through the prepreg shell. The staggered arrangement can avoid the rapid transfer of heat through the prepreg shell. Furthermore, the staggered arrangement of the box-shaped parts also makes the wedge sound-absorbing structure of the aerogel processing staggered, which has a better sound absorption effect.

[0053] Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

Claims

1. An integrated composite material for heat protection and sound absorption, characterized in that: It includes an outer surface layer and an inner surface layer, with a sound-absorbing and heat-insulating layer between the outer surface layer and the inner surface layer. The outer surface layer includes a top layer and at least one inner layer. The top layer is made of polysilazane-modified silane-containing aromatic resin, oxide powder, and quartz fiber. The inner layer is made of boron phenolic resin, oxide powder, and quartz fiber. The oxide powder content of the inner layer is less than that of the top layer.

2. The integrated heat-resistant and sound-absorbing composite material according to claim 1, characterized in that: The outer surface layer comprises a surface layer and at least two inner layers, wherein the content of the oxide powder decreases progressively from the surface layer to the inner layers.

3. The integrated heat-resistant and sound-absorbing composite material according to any one of claims 1 or 2, characterized in that: The sound-absorbing and heat-insulating layer is composed of multiple box-shaped components stacked one on top of the other. Each box-shaped component includes an aerogel core and a prepreg shell covering the aerogel core around its perimeter and bottom. The aerogel core is processed into a wedge-shaped sound-absorbing structure, and the box-shaped components in adjacent layers are staggered.

4. The integrated heat-resistant and sound-absorbing composite material according to claim 3, characterized in that: The wedge-shaped sound-absorbing structures in adjacent layers are also staggered.

5. The integrated heat-resistant and sound-absorbing composite material according to claim 3, characterized in that: The prepreg shell is formed by laying and pre-curing a fiber matrix and a boron phenolic resin prepreg. The fiber matrix is ​​any one of glass fiber, basalt fiber or alumina fiber.

6. The integrated heat-resistant and sound-absorbing composite material according to claim 3, characterized in that: The inner surface layer is a carbon fiber composite material, specifically a prepreg of carbon fiber and bismaleimide resin.

7. The integrated heat-resistant and sound-absorbing composite material according to claim 3, characterized in that: The oxide powder is any one of zirconium oxide, magnesium oxide, or beryllium oxide.

8. A method for preparing an integrated heat-resistant and sound-absorbing composite material, used to prepare the integrated heat-resistant and sound-absorbing composite material as described in claim 1, characterized in that: The method includes: Step S100, preparation of the outer surface layer, includes the preparation of a surface prepreg and an inner prepreg. The preparation of the surface prepreg includes impregnating quartz fibers in a polysilazane-modified silane-containing aromatic resin mixed with oxide powder to obtain the surface prepreg. The preparation of the inner prepreg includes impregnating quartz fibers in a boron phenolic resin mixed with oxide powder to obtain the inner prepreg. The surface prepreg and at least one inner prepreg are stacked together to obtain the outer surface layer. The oxide powder content in the inner prepreg is greater than the oxide powder content in the surface prepreg. Step S110, preparation of sound-absorbing and heat-insulating layer, wherein the sound-absorbing and heat-insulating layer is composed of multiple box-shaped components stacked in upper and lower layers, wherein the box-shaped components include an aerogel core and a prepreg shell covering the aerogel core around and on the bottom surface, and a wedge sound-absorbing structure is processed on the aerogel core. Step S120, preparation of the inner surface layer, wherein the preparation of the inner surface layer includes laying it up using a prepreg of carbon fiber and bismaleimide resin; Step S130: The inner surface layer, the sound-absorbing and heat-insulating layer and the outer surface layer are laid in sequence and co-cured to obtain an integrated composite material with heat-insulating and sound-absorbing structure.

9. The method for preparing the integrated heat-resistant and sound-absorbing composite material according to claim 8, characterized in that: The outer surface layer in step S100 comprises a surface prepreg and at least two inner prepregs stacked together, wherein the content of oxide powder in the inner prepreg gradually decreases.

10. The method for preparing the integrated heat-resistant and sound-absorbing composite material according to claim 8, characterized in that: In step S110, the upper and lower box-shaped components are misaligned, and the wedge-shaped sound-absorbing structure on the aerogel core is also misaligned.

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