Flexible high-temperature-resistant aerogel composite material and preparation method thereof

Abstract

The invention relates to a flexible high-temperature-resistant aerogel composite material and a preparation method thereof. The method comprises the following steps: crushing and screening high-temperature-resistant aerogel to obtain high-temperature-resistant aerogel particles; putting the high-temperature-resistant aerogel particles, the silicon carbide whiskers, the boron nitride nanosheets and the ceramic fibers into an aqueous solution containing a foaming agent and a setting agent, and uniformly stirring to obtain slurry; the ceramic fibers are magnesium aluminate spinel nanofibers and mullite micron fibers; and carrying out filter pressing on the slurry, and sequentially carrying out normal-pressure drying, freeze drying and calcination to prepare the flexible high-temperature-resistant aerogel composite material. According to the flexibility method of the high-temperature-resistant aerogel, the requirement for high-temperature flexible heat insulation is met, and the flexible high-temperature-resistant aerogel composite material with excellent tensile strength is obtained; the material prepared by the method is good in flexibility, excellent in tensile strength performance and excellent in high-temperature heat conductivity coefficient, and has a wide application prospect in the field of high-temperature and / or ultrahigh-temperature flexible thermal protection in the future.

Description

Technical Field

[0001] This invention belongs to the field of aerogel composite material technology, and particularly relates to a flexible high-temperature resistant aerogel composite material and its preparation method. Background Technology

[0002] The high Mach number flight and long-duration operation characteristics of next-generation aerospace vehicles create an increasingly urgent need for lightweight, high-temperature resistant, and flexible thermal protection materials. Aerogels, prepared through sol-gel combined supercritical drying technology, possess high porosity and high thermal resistance properties; in particular, inorganic aerogels, with their high-temperature resistance, lightweight, and highly efficient thermal insulation characteristics, have become ideal thermal protection materials for next-generation aerospace equipment.

[0003] Currently, research on inorganic aerogels mainly focuses on silica aerogels and alumina aerogels. These aerogels have certain limitations in temperature resistance, and with the continuous increase in external ambient temperatures of spacecraft, single-component oxide aerogels are finding it increasingly difficult to meet application requirements. Multi-component spinel aerogels and / or zirconium-based multi-component oxide aerogels have emerged as new solutions to address the temperature resistance issues of aerogels. However, most of these aerogels require high-temperature heat treatment, and these aerogel materials exhibit rigid characteristics. Therefore, the development of high-temperature resistant, high-thermal-resistance (excellent thermal insulation) flexible aerogels remains a significant challenge, and new preparation methods are urgently needed. Summary of the Invention

[0004] To address one or more technical problems existing in the prior art, this invention provides a flexible high-temperature resistant aerogel composite material and its preparation method.

[0005] The present invention provides a method for preparing a flexible high-temperature resistant aerogel composite material in a first aspect, the method comprising the following steps: (1) The high-temperature resistant aerogel is crushed and sieved to obtain high-temperature resistant aerogel particles; (2) The high-temperature resistant aerogel particles, silicon carbide whiskers, boron nitride nanosheets and ceramic fibers are placed in an aqueous solution containing a foaming agent and a setting agent and stirred evenly to obtain a slurry; the ceramic fibers are magnesium aluminum spinel nanofibers and mullite microfibers; (3) The slurry is filtered by pressure, and then dried by normal pressure, freeze-dried and calcined in sequence to obtain a flexible high-temperature resistant aerogel composite material.

[0006] Preferably, the particle size of the high-temperature resistant aerogel particles is no greater than 10 μm.

[0007] Preferably, the mass ratio of the high-temperature resistant aerogel particles to the ceramic fibers is 1:(1~5); and / or the mass ratio of the mullite microfibers to the magnesium aluminum spinel nanofibers is (1~2):(1~3).

[0008] Preferably, the mass ratio of the silicon carbide whiskers to the high-temperature resistant aerogel particles is 1:(10~20); and / or the mass ratio of the boron nitride nanosheets to the ceramic fibers is 1:(20~30).

[0009] Preferably, the foaming agent is a surfactant, and more preferably, the foaming agent is one or more of sodium dodecylbenzenesulfonate, sodium dodecyl sulfonate, and dodecyltrimethylammonium bromide; and / or the setting agent is gellan gum and hydroxypropyl methylcellulose, and more preferably, the mass ratio of gellan gum to hydroxypropyl methylcellulose is (2~4):1.

[0010] Preferably, the aqueous solution contains 0.01-10% by mass of foaming agent, more preferably 0.05-2%; and / or the aqueous solution contains 0.5-3% by mass of setting agent.

[0011] Preferably, the pressure of the filter press is 0.5~1MPa.

[0012] Preferably, the temperature of the atmospheric pressure drying is 50~90℃; and / or the temperature of the calcination is 600~1000℃.

[0013] Preferably, the high-temperature resistant aerogel is a spinel-structured high-temperature resistant aerogel.

[0014] The present invention provides, in a second aspect, a flexible high-temperature resistant aerogel composite material prepared by the preparation method described in the first aspect of the present invention.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects: This invention provides a method for making high-temperature resistant aerogel flexible, addressing the need for flexible thermal insulation at high temperatures. The invention uses high-temperature resistant aerogel particles as the basic unit, aluminum-magnesium spinel nanofibers and mullite microfibers as flexible and controllable supports, a foaming agent to construct the foam structure, a setting agent as a foam stabilizer and fiber dispersant, and high-pressure filtration to achieve rapid shaping of the aerogel composite material. Finally, a combination of atmospheric pressure drying-freeze drying and calcination is used to obtain a flexible high-temperature resistant aerogel composite material with excellent tensile strength. The material prepared by this method exhibits good flexibility, excellent tensile strength, and excellent high-temperature thermal conductivity, showing broad application prospects in the field of high-temperature and / or ultra-high-temperature flexible thermal protection. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments thereof. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0017] The present invention provides a method for preparing a flexible high-temperature resistant aerogel composite material in a first aspect, the method comprising the following steps: (1) The high-temperature resistant aerogel is crushed and sieved to obtain high-temperature resistant aerogel particles (which can also be referred to as high-temperature resistant aerogel powder); the present invention does not specifically limit the source of the high-temperature resistant aerogel, and can use products that are purchased directly or products prepared by existing methods; in the present invention, for example, grinding and sieving equipment is used to crush and sieve to obtain high-temperature resistant aerogel particles within a certain particle size range; specifically, step (1) is, for example, placing the high-temperature resistant aerogel in a grinding equipment for crushing treatment, and then sieving high-temperature resistant aerogel particles with a particle size of less than 10μm through a sieving equipment (sieve). If the particles are too large, they are not easy to disperse effectively, which is not conducive to subsequent molding; (2) High-temperature resistant aerogel particles, silicon carbide whiskers, boron nitride nanosheets and ceramic fibers are placed in an aqueous solution containing a foaming agent and a setting agent and stirred evenly to obtain a slurry; the ceramic fibers are magnesium aluminum spinel nanofibers and mullite microfibers; the present invention does not limit the specific size of magnesium aluminum spinel nanofibers and mullite microfibers, as long as they are nanofibers and microfibers, they can be selected conventionally by those skilled in the art, for example, the diameter of the magnesium aluminum spinel nanofibers is 100~800nm, and the diameter of the mullite microfibers is 1~8μm; this process is a multidimensional system mixing and dispersion, involving the selection of components and uniform dispersion; in the present invention, the aqueous solution containing the foaming agent and the setting agent is a mixture of the foaming agent, the setting agent and water; the present invention does not limit the conditions for uniform stirring, and those skilled in the art can select conventionally, for example, the stirring speed can be 300~800r / min, the stirring time is 10~30min, and the slurry is formed by rapid stirring and uniform dispersion; (3) The slurry is pressure filtered, then successively dried under normal pressure (drying at atmospheric pressure), freeze-dried, and calcined to obtain a flexible high-temperature resistant aerogel composite material; In this invention, for example, the slurry is placed in a plate and frame apparatus and rapidly pressure filtered and shaped in a filter press (the pressure filtering time is, for example, 2~8 min), then placed together with the plate and frame apparatus in an oven for normal pressure drying (the normal pressure drying time is, for example, 1~3 h), then rapidly freeze-dried (the freeze-drying temperature is, for example, -20℃~-40℃, and the freeze-drying time is, for example, 12~24 h), and finally subjected to high-temperature calcination treatment (the high-temperature calcination treatment time is, for example, 8~16 h), and the sample is separated from the plate and frame apparatus to obtain the flexible high-temperature resistant aerogel composite material. The invention employs a method of first drying under normal pressure and then freeze-drying, which ensures the effective preservation of the nanoporous structure. Furthermore, calcination is performed, which facilitates the sintering and adhesion of boron nitride nanosheets to the fiber surface, ultimately enhancing the tensile strength, structural stability, and high-temperature insulation performance of the flexible high-temperature resistant aerogel composite material. The flexible high-temperature resistant aerogel composite material obtained by this invention exhibits both low thermal conductivity (e.g., thermal conductivity not greater than 0.096 W / (m·K) at 1500℃) and excellent tensile strength (e.g., tensile strength not less than 0.30 MPa at 1500℃) under ultra-high temperature conditions above 1500℃, demonstrating outstanding comprehensive performance and can be considered a flexible ultra-high temperature resistant aerogel composite material.

[0018] This invention provides a novel, low-cost method for preparing flexible, high-temperature resistant aerogel composite materials based on wet molding. Specifically, it addresses the need for flexible high-temperature insulation by making the aerogel more flexible. The invention uses high-temperature resistant aerogel particles as the basic unit, aluminum-magnesium spinel nanofibers and mullite microfibers as flexible and controllable supports, a foaming agent to construct the foam structure, a setting agent as a foam stabilizer and fiber dispersant, and high-pressure filtration to achieve rapid shaping of the aerogel composite material. Finally, a combination of high-pressure drying-freeze drying and calcination is used to obtain a flexible, high-temperature resistant aerogel composite material with excellent tensile strength. The material prepared by this method exhibits good flexibility, excellent tensile strength, and excellent high-temperature thermal conductivity, showing broad application prospects in the field of high-temperature and / or ultra-high-temperature flexible thermal protection.

[0019] In this invention, the selected magnesium aluminum spinel nanofibers and mullite microfibers play a flexible and controllable supporting role in the aerogel composite material. Magnesium aluminum spinel nanofibers have excellent high-temperature stability and creep resistance, and can maintain structural integrity in ultra-high temperature environments. At the same time, their nanoscale characteristics help to enhance the compactness and tensile strength of the aerogel composite material. Mullite microfibers can indirectly reduce the thermal conductivity of the aerogel composite material at high temperatures and improve the flexibility and high-temperature tensile strength of the material by forming a skeleton, introducing pores, and resisting thermal shock. The synergistic effect of the two helps to ensure that the resulting aerogel composite material can maintain low thermal conductivity and high tensile strength above 1500℃, solving the problems of high brittleness and poor tensile strength of traditional aerogels. If other types of nanofibers or microfibers, such as alumina fibers, aluminum silicate fibers, quartz fibers, or zirconium oxide fibers, are used, although they also have high temperature resistance, they may have problems such as structural instability at high temperatures, large thermal shrinkage, insufficient flexibility, and / or a significant decrease in tensile strength.

[0020] According to some preferred embodiments, the particle size of the high-temperature resistant aerogel particles is not greater than 10 μm (0 < particle size ≤ 10 μm); in this invention, the particle size of the high-temperature resistant aerogel particles can preferably be 1~10 μm, for example.

[0021] According to some preferred embodiments, the mass ratio of the high-temperature resistant aerogel particles to the ceramic fibers is 1:(1~5) (e.g., 1:1, 1:2, 1:3, 1:4, or 1:5); in this invention, it is preferable to control the mass ratio of the high-temperature resistant aerogel particles to the ceramic fibers at 1:5~1:1, so that the ceramic fibers can be effectively inserted into the interior of the high-temperature resistant aerogel particles, effectively supporting the aerogel powder and the fiber network structure, avoiding shrinkage and cracking of the powder, and improving the mechanical properties of the material; and / or the mass ratio of the mullite microfibers to the magnesium aluminum spinel nanofibers is (1~2):(1~ 3) (e.g., 1:1, 1:2, 1:3, 2:1 or 2:3); In this invention, it is preferred to control the mass ratio of the mullite microfibers and magnesium aluminum spinel nanofibers to be 1:3 to 2:1. This can create a good synergistic effect between micron-level reinforcement and nano-level support, so that the two types of fibers are evenly distributed in the aerogel composite material. This ratio can avoid structural inhomogeneity and insufficient tensile strength caused by excessive mullite microfibers, and can also prevent the problems of increased brittleness and insufficient flexibility caused by excessive magnesium aluminum spinel nanofibers. Thus, it can achieve a combination of low thermal conductivity and high tensile strength under ultra-high temperature conditions.

[0022] According to some preferred embodiments, the mass ratio of the silicon carbide whiskers to the high-temperature resistant aerogel particles is 1:(10~20) (e.g., 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19, or 1:20). In this invention, the silicon carbide whiskers act as a radiation-resistant agent, which can improve the high-temperature thermal insulation performance of the material. The preferred ratio is 1:(10~20). If the mass fraction of silicon carbide whiskers is too low, the high-temperature insulation performance will be poor; if the mass fraction is too high, it will lead to insufficient flexibility of the subsequent material. And / or the mass ratio of the boron nitride nanosheets to the ceramic fibers is 1:(20~30) (e.g., 1:20, 1:21, 1:22, 1:23, 1:24, 1:25, 1:26, 1:27, 1:28, 1:29, or 1:30). In this invention, the boron nitride nanosheets serve as a high-temperature sintering agent. During high-temperature calcination, they adhere to the fiber surface, filling the micropores between the fibers and aerogel particles, enhancing interfacial bonding, and thus effectively improving the tensile strength of the material. The two-dimensional structure of the BN nanosheets acts as a "bridging" agent at the microscale, making the aerogel skeleton and fiber network more compact, dispersing stress, reducing local stress concentration during stretching, and improving overall mechanical properties. In this invention, it is preferable to control the mass ratio of the boron nitride nanosheets to the ceramic fibers to be 1:(20~30). If the amount of BN nanosheets is too small, the interfacial filling is insufficient, the bonding force between the fibers and particles is weak, the tensile strength improvement is limited, and the material is still prone to fracture. If the amount is too large, the BN nanosheets may accumulate in local areas, generating microcrack initiation points, affecting the pore structure of the material, reducing flexibility and tensile toughness, and may also increase thermal conductivity, weakening high-temperature insulation performance.

[0023] According to some preferred embodiments, the foaming agent is a surfactant, preferably one or more of sodium dodecylbenzenesulfonate, sodium dodecyl sulfonate, and dodecyltrimethylammonium bromide; and / or the setting agent is gellan gum and hydroxypropyl methylcellulose, preferably, the mass ratio of gellan gum (also referred to as biogellan gum) to hydroxypropyl methylcellulose is (2~4):1 (e.g., 2:1, 3:1, or 4:1); To ensure effective dispersion, foam structure construction, foam stability, and subsequent efficient setting of the multi-component system, the present invention requires the addition of a foaming agent and a setting agent to the aqueous solution; in the present invention, preferably... The selected ratio is (2~4):1, where gellan gum acts as the main sizing agent, facilitating the formation of a stable three-dimensional network skeleton in the slurry, providing support for fibers and aerogel particles, thereby imparting good flexibility and molding strength to the material. Hydroxypropyl methylcellulose acts as an auxiliary sizing agent, adjusting the slurry viscosity, improving the dispersibility of particles and fibers, and preventing sedimentation or agglomeration during pressure filtration and drying. This controlled ratio helps ensure uniform slurry and structural stability, enabling the flexible high-temperature resistant aerogel composite material to simultaneously possess low thermal conductivity and high tensile strength (good flexibility). Unless otherwise specified, all raw materials used in this invention can be directly purchased or prepared using existing methods.

[0024] According to some preferred embodiments, the aqueous solution contains a foaming agent at a mass percentage of 0.01 to 10% (e.g., 0.01%, 0.05%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%), preferably 0.05 to 2% (e.g., 0.05%, 0.08%, 1%, 1.5%, or 2%).

[0025] According to some preferred embodiments, the aqueous solution contains a shaping agent at a mass percentage of 0.5-3% (e.g., 0.5%, 1%, 1.5%, 2%, 2.5%, or 3%). In this invention, it is preferable to control the concentration of the foaming agent to be 0.05-2% and the concentration of the shaping agent to be 0.5-3%, which can satisfy the subsequent shaping requirements and bubble stability, while avoiding excessive organic matter that would lead to excessive shrinkage in the subsequent drying process, reducing the efficiency of material molding and the flexibility of the material.

[0026] According to some preferred embodiments, the pressure of the filter press is 0.5~1MPa (e.g. 0.5, 0.6, 0.7, 0.8, 0.9 or 1MPa). In this invention, the pressure of the filter press molding is preferably 0.5~1MPa, which is several times the atmospheric pressure, so as to facilitate rapid shaping.

[0027] According to some preferred embodiments, the temperature of the atmospheric pressure drying is 50~90℃ (e.g., 50℃, 60℃, 70℃, 80℃ or 90℃); and / or the temperature of the calcination is 600~1000℃ (e.g., 600℃, 700℃, 800℃, 900℃ or 1000℃).

[0028] According to some preferred embodiments, the high-temperature resistant aerogel is a spinel-structured high-temperature resistant aerogel; in this invention, when the high-temperature resistant aerogel is a spinel-structured high-temperature resistant aerogel, the resulting flexible high-temperature resistant aerogel composite material is a multi-scale fiber-reinforced flexible magnesium-aluminum spinel-type aerogel composite material; this invention does not specifically limit the source of the spinel-structured high-temperature resistant aerogel; in this invention, for example, a spinel-structured high-temperature resistant aerogel can be synthesized with reference to Chinese patent application 202410945695.4. Specifically, the preparation of the spinel-structured high-temperature resistant aerogel includes: S1. Disperse nano-alumina sol and nano-magnesium oxide evenly with water to obtain a dispersion. Then add a structure modifier and a mineralizer to the dispersion and carry out a hydrothermal reaction to obtain a composite precursor sol. S2. Add polyethylene oxide to the composite precursor sol and mix evenly to obtain the impregnation solution; S3. The zirconium oxide nanofiber membrane is placed in the impregnation solution for impregnation and swelling to obtain an impregnated and swollen nanofiber membrane; S4. Multiple impregnated and swollen nanofiber membranes are stacked layer by layer, pre-frozen with liquid nitrogen and freeze-dried, and then calcined at high temperature to obtain spinel structure high-temperature resistant aerogel.

[0029] The present invention provides, in a second aspect, a flexible high-temperature resistant aerogel composite material prepared by the preparation method described in the first aspect of the present invention.

[0030] The present invention will be further described below by way of examples, but the scope of protection of the present invention is not limited to these embodiments.

[0031] The high-temperature resistant aerogel used in the following examples and comparative examples is a spinel-structured high-temperature resistant aerogel, which is prepared as follows: S1. Weigh 30 parts of nano-alumina sol (nano-alumina solid content is 25wt%) and 6 parts of nano-magnesium oxide, add them to water and disperse evenly to obtain a dispersion. The dispersion contains a total mass percentage of 15% nano-alumina and nano-magnesium oxide. Then, add a 5mol / L oxalic acid aqueous solution as a structure modifier and lithium fluoride powder as a mineralizing agent to the dispersion and perform a hydrothermal reaction at 240℃ for 48h to prepare a composite precursor sol. The mass amount of the oxalic acid aqueous solution is 4% of the sum of the mass amounts of nano-alumina and nano-magnesium oxide contained in the nano-alumina sol. The mass amount of the lithium fluoride powder is 1.5% of the sum of the mass amounts of nano-alumina and nano-magnesium oxide contained in the nano-alumina sol.

[0032] S2. Add polyethylene oxide (PEO) to the composite precursor sol system obtained above and stir to mix evenly to obtain an impregnation solution; wherein the mass ratio of polyethylene oxide (PEO) to composite precursor sol is 0.2:99.

[0033] S3. A zirconia nanofiber membrane with a thickness of 0.5 mm is immersed and swollen in the impregnation solution obtained in step S2 for 5 hours to obtain an impregnated and swollen nanofiber membrane.

[0034] S4. Remove the impregnated and swollen nanofiber membrane from the impregnation solution and remove excess solution from the surface. Stack 20 impregnated and swollen nanofiber membranes with excess solution removed layer by layer, pre-freeze them rapidly with liquid nitrogen for 30 minutes to form a solid shape, freeze-dry them for 72 hours, and then calcine them at 1400℃ for 2 hours to obtain a spinel structure high-temperature resistant aerogel.

[0035] In this invention, unless otherwise specified, "part" refers to "parts by weight". In specific embodiments and comparative examples, the unit of "part" can be uniformly "g" or "kg" or other weight units.

[0036] Example 1 (1) The spinel structure high temperature resistant aerogel is placed in a grinding and screening device for crushing and screening to obtain high temperature resistant aerogel particles with a particle size of less than 10 μm.

[0037] (2) Weigh 30 parts of ceramic fiber (the mass ratio of mullite microfiber and magnesium aluminum spinel nanofiber is 1:2), 30 parts of high temperature resistant aerogel particles (the mass ratio of high temperature resistant aerogel particles to ceramic fiber is 1:1), 3 parts of silicon carbide whiskers (the mass ratio of silicon carbide whiskers to high temperature resistant aerogel particles is 1:10) and 1.5 parts of boron nitride nanosheets (the mass ratio of boron nitride nanosheets to ceramic fiber is 1:20) and place them in an aqueous solution containing 2 wt% foaming agent sodium dodecylbenzenesulfonate and 3 wt% sizing agent (2 wt% gellan gum and 1 wt% hydroxypropyl methylcellulose), and quickly stir to disperse into a slurry.

[0038] (3) The above slurry is placed in a plate and frame device for rapid pressure filtration and shaping. The pressure of the pressure filtration is 1 MPa and the filtration time is 3 min. Then the slurry and the plate and frame device are placed in an oven for normal pressure drying. The drying temperature is 60℃ and the drying time is 2 h. Then it is rapidly freeze-dried. The freeze-drying temperature is -28℃ and the freeze-drying time is 12 h to obtain the flexible composite material to be calcined. Finally, it is calcined at 800℃ for 12 h to obtain the flexible high temperature resistant aerogel composite material.

[0039] Example 2 (1) The spinel structure high temperature resistant aerogel is placed in a grinding and screening device for crushing and screening to obtain high temperature resistant aerogel particles with a particle size of less than 10 μm.

[0040] (2) Weigh 30 parts of ceramic fiber (the mass ratio of mullite microfiber and magnesium aluminum spinel nanofiber is 2:1), 6 parts of high temperature resistant aerogel particles (the mass ratio of high temperature resistant aerogel particles to ceramic fiber is 1:5), 0.6 parts of silicon carbide whiskers (the mass ratio of silicon carbide whiskers to high temperature resistant aerogel particles is 1:10) and 1 part of boron nitride nanosheets (the mass ratio of boron nitride nanosheets to ceramic fiber is 1:30) and place them in an aqueous solution containing 0.05 wt% foaming agent sodium dodecylbenzenesulfonate and 3 wt% sizing agent (2 wt% gellan gum and 1 wt% hydroxypropyl methylcellulose), and quickly stir to disperse into a slurry.

[0041] (3) The above slurry is placed in a plate and frame device for rapid pressure filtration and shaping. The pressure of the filtration is 0.5 MPa and the filtration time is 3 min. Then the slurry is placed in an oven with the plate and frame device for normal pressure drying. The drying temperature is 70℃ and the drying time is 2 h. Then it is rapidly freeze-dried. The freeze-drying temperature is -28℃ and the freeze-drying time is 12 h. Finally, it is calcined at 600℃ for 12 h to obtain a flexible high-temperature resistant aerogel composite material.

[0042] Example 3 (1) The spinel structure high temperature resistant aerogel is placed in a grinding and screening device for crushing and screening to obtain high temperature resistant aerogel particles with a particle size of less than 10 μm.

[0043] (2) Weigh 40 parts of ceramic fiber (the mass ratio of mullite microfiber and magnesium aluminum spinel nanofiber is 1:1), 20 parts of high temperature resistant aerogel particles (the mass ratio of high temperature resistant aerogel particles to ceramic fiber is 1:2), 2 parts of silicon carbide whiskers (the mass ratio of silicon carbide whiskers to high temperature resistant aerogel particles is 1:10) and 2 parts of boron nitride nanosheets (the mass ratio of boron nitride nanosheets to ceramic fiber is 1:20) and place them in an aqueous solution containing 1 wt% foaming agent sodium dodecylbenzenesulfonate and 3 wt% setting agent (2 wt% gellan gum and 1 wt% hydroxypropyl methylcellulose), and quickly stir to disperse into a slurry.

[0044] (3) The above slurry was placed in a plate and frame device for rapid pressure filtration and shaping. The pressure of the pressure filtration was 0.8 MPa and the filtration time was 3 min. Then the slurry and the plate and frame device were placed in an oven for normal pressure drying. The drying temperature was 90℃ and the drying time was 2 h. Then it was rapidly freeze-dried. The freeze-drying temperature was -28℃ and the freeze-drying time was 12 h. Finally, it was calcined at 1000℃ for 12 h to obtain a flexible high-temperature resistant aerogel composite material.

[0045] Example 4 (1) The spinel structure high temperature resistant aerogel is placed in a grinding and screening device for crushing and screening to obtain high temperature resistant aerogel particles with a particle size of less than 10 μm.

[0046] (2) Weigh 40 parts of ceramic fiber (the mass ratio of mullite microfiber and magnesium aluminum spinel nanofiber is 1:3), 20 parts of high temperature resistant aerogel particles (the mass ratio of high temperature resistant aerogel particles to ceramic fiber is 1:2), 1 part of silicon carbide whiskers (the mass ratio of silicon carbide whiskers to high temperature resistant aerogel particles is 1:20) and 2 parts of boron nitride nanosheets (the mass ratio of boron nitride nanosheets to ceramic fiber is 1:20) and place them in an aqueous solution containing 1 wt% foaming agent sodium dodecylbenzenesulfonate and 3 wt% sizing agent (2 wt% gellan gum and 1 wt% hydroxypropyl methylcellulose), and quickly stir to disperse into a slurry.

[0047] (3) The above slurry was placed in a plate and frame device for rapid pressure filtration and shaping. The pressure of the pressure filtration was 0.8 MPa and the filtration time was 3 min. Then the slurry and the plate and frame device were placed in an oven for normal pressure drying. The drying temperature was 70℃ and the drying time was 2 h. Then it was rapidly freeze-dried. The freeze-drying temperature was -28℃ and the freeze-drying time was 12 h. Finally, it was calcined at 900℃ for 12 h to obtain a flexible high-temperature resistant aerogel composite material.

[0048] Example 5 (1) The spinel structure high temperature resistant aerogel is placed in a grinding and screening device for crushing and screening to obtain high temperature resistant aerogel particles with a particle size of less than 10 μm.

[0049] (2) Weigh 40 parts of ceramic fiber (the mass ratio of mullite microfiber and magnesium aluminum spinel nanofiber is 1:3), 20 parts of high temperature resistant aerogel particles (the mass ratio of high temperature resistant aerogel particles to ceramic fiber is 1:2), 1.33 parts of silicon carbide whiskers (the mass ratio of silicon carbide whiskers to high temperature resistant aerogel particles is 1:15) and 2 parts of boron nitride nanosheets (the mass ratio of boron nitride nanosheets to ceramic fiber is 1:20) and place them in an aqueous solution containing 1 wt% foaming agent sodium dodecylbenzenesulfonate and 2 wt% sizing agent (1.5 wt% gellan gum and 0.5 wt% hydroxypropyl methylcellulose), and quickly stir to disperse into a slurry.

[0050] (3) The above slurry was placed in a plate and frame device for rapid pressure filtration and shaping. The pressure of the pressure filtration was 0.8 MPa and the filtration time was 3 min. Then the slurry and the plate and frame device were placed in an oven for normal pressure drying. The drying temperature was 70℃ and the drying time was 2 h. Then it was rapidly freeze-dried. The freeze-drying temperature was -28℃ and the freeze-drying time was 12 h. Finally, it was calcined at 900℃ for 12 h to obtain a flexible high-temperature resistant aerogel composite material.

[0051] Example 6 (1) The spinel structure high temperature resistant aerogel is placed in a grinding and screening device for crushing and screening to obtain high temperature resistant aerogel particles with a particle size of less than 10 μm.

[0052] (2) Weigh 40 parts of ceramic fiber (the mass ratio of mullite microfiber and magnesium aluminum spinel nanofiber is 1:3), 20 parts of high temperature resistant aerogel particles (the mass ratio of high temperature resistant aerogel particles to ceramic fiber is 1:2), 1.33 parts of silicon carbide whiskers (the mass ratio of silicon carbide whiskers to high temperature resistant aerogel particles is 1:15) and 2 parts of boron nitride nanosheets (the mass ratio of boron nitride nanosheets to ceramic fiber is 1:20) and place them in an aqueous solution containing 1 wt% foaming agent sodium dodecylbenzenesulfonate and 0.5 wt% sizing agent (0.4 wt% gellan gum and 0.1 wt% hydroxypropyl methylcellulose), and quickly stir to disperse into a slurry.

[0053] (3) The above slurry was placed in a plate and frame device for rapid pressure filtration and shaping. The pressure of the pressure filtration was 0.8 MPa and the filtration time was 3 min. Then the slurry and the plate and frame device were placed in an oven for normal pressure drying. The drying temperature was 70℃ and the drying time was 2 h. Then it was rapidly freeze-dried. The freeze-drying temperature was -28℃ and the freeze-drying time was 12 h. Finally, it was calcined at 900℃ for 12 h to obtain a flexible high-temperature resistant aerogel composite material.

[0054] Comparative Example 1 (1) The spinel structure high temperature resistant aerogel is placed in a grinding and screening equipment for crushing and screening to obtain high temperature resistant aerogel particles with a particle size of 20~50μm.

[0055] (2) Weigh 40 parts of ceramic fiber (the mass ratio of mullite microfiber and magnesium aluminum spinel nanofiber is 1:3), 20 parts of high temperature resistant aerogel particles (the mass ratio of high temperature resistant aerogel particles to ceramic fiber is 1:2), 1.33 parts of silicon carbide whiskers (the mass ratio of silicon carbide whiskers to high temperature resistant aerogel particles is 1:15) and 2 parts of boron nitride nanosheets (the mass ratio of boron nitride nanosheets to ceramic fiber is 1:20) and place them in an aqueous solution containing 1 wt% foaming agent sodium dodecylbenzenesulfonate and 0.5 wt% sizing agent (0.4 wt% gellan gum and 0.1 wt% hydroxypropyl methylcellulose), and quickly stir to disperse into a slurry.

[0056] (3) The above slurry was placed in a plate and frame device for rapid pressure filtration and shaping. The pressure of the filtration was 0.8 MPa and the filtration time was 3 min. Then the slurry and the plate and frame device were placed in an oven for normal pressure drying. The drying temperature was 70℃ and the drying time was 2 h. Then it was rapidly freeze-dried. The freeze-drying temperature was -28℃ and the freeze-drying time was 12 h. Finally, it was calcined at 900℃ for 12 h to obtain the aerogel composite material.

[0057] Comparative Example 2 (1) The spinel structure high temperature resistant aerogel is placed in a grinding and screening device for crushing and screening to obtain high temperature resistant aerogel particles with a particle size of less than 10 μm.

[0058] (2) Weigh 40 parts of ceramic fiber (the mass ratio of mullite microfiber and magnesium aluminum spinel nanofiber is 1:3), 80 parts of high temperature resistant aerogel particles (the mass ratio of high temperature resistant aerogel particles to ceramic fiber is 2:1), 8 parts of silicon carbide whiskers (the mass ratio of silicon carbide whiskers to high temperature resistant aerogel particles is 1:10) and 2 parts of boron nitride nanosheets (the mass ratio of boron nitride nanosheets to ceramic fiber is 1:20) and place them in an aqueous solution containing 1 wt% foaming agent sodium dodecylbenzenesulfonate and 0.5 wt% sizing agent (0.4 wt% gellan gum and 0.1 wt% hydroxypropyl methylcellulose), and quickly stir to disperse into a slurry.

[0059] (3) The above slurry was placed in a plate and frame device for rapid pressure filtration and shaping. The pressure of the filtration was 0.8 MPa and the filtration time was 3 min. Then the slurry and the plate and frame device were placed in an oven for normal pressure drying. The drying temperature was 70℃ and the drying time was 2 h. Then it was rapidly freeze-dried. The freeze-drying temperature was -28℃ and the freeze-drying time was 12 h. Finally, it was calcined at 900℃ for 12 h to obtain the aerogel composite material.

[0060] Comparative Example 3 (1) The spinel structure high temperature resistant aerogel is placed in a grinding and screening device for crushing and screening to obtain high temperature resistant aerogel particles with a particle size of less than 10 μm.

[0061] (2) Weigh 40 parts of ceramic fiber (the mass ratio of mullite microfiber and magnesium aluminum spinel nanofiber is 1:3), 20 parts of high temperature resistant aerogel particles (the mass ratio of high temperature resistant aerogel particles to ceramic fiber is 1:2), 1.33 parts of silicon carbide whiskers (the mass ratio of silicon carbide whiskers to high temperature resistant aerogel particles is 1:15) and 2 parts of boron nitride nanosheets (the mass ratio of boron nitride nanosheets to ceramic fiber is 1:20) and place them in an aqueous solution containing 0.5 wt% of a setting agent (0.4 wt% gellan gum and 0.1 wt% hydroxypropyl methylcellulose), and quickly stir to disperse into a slurry.

[0062] (3) The above slurry was placed in a plate and frame device for rapid pressure filtration and shaping. The pressure of the filtration was 0.8 MPa and the filtration time was 3 min. Then the slurry and the plate and frame device were placed in an oven for normal pressure drying. The drying temperature was 70℃ and the drying time was 2 h. Then it was rapidly freeze-dried. The freeze-drying temperature was -28℃ and the freeze-drying time was 12 h. Finally, it was calcined at 900℃ for 12 h to obtain the aerogel composite material.

[0063] Comparative Example 4 (1) The spinel structure high temperature resistant aerogel is placed in a grinding and screening device for crushing and screening to obtain high temperature resistant aerogel particles with a particle size of less than 10 μm.

[0064] (2) Weigh 40 parts of ceramic fiber (the mass ratio of mullite microfiber and magnesium aluminum spinel nanofiber is 1:3), 20 parts of high temperature resistant aerogel particles (the mass ratio of high temperature resistant aerogel particles to ceramic fiber is 1:2), 1.33 parts of silicon carbide whiskers (the mass ratio of silicon carbide whiskers to high temperature resistant aerogel particles is 1:15) and 2 parts of boron nitride nanosheets (the mass ratio of boron nitride nanosheets to ceramic fiber is 1:20) and place them in an aqueous solution containing 1 wt% foaming agent sodium dodecylbenzenesulfonate, and quickly stir to disperse into a slurry.

[0065] (3) The above slurry was placed in a plate and frame device for rapid pressure filtration and shaping. The pressure of the filtration was 0.8 MPa and the filtration time was 3 min. Then the slurry and the plate and frame device were placed in an oven for normal pressure drying. The drying temperature was 70℃ and the drying time was 2 h. Then it was rapidly freeze-dried. The freeze-drying temperature was -28℃ and the freeze-drying time was 12 h. Finally, it was calcined at 900℃ for 12 h to obtain the aerogel composite material.

[0066] Comparative Example 5 (1) The spinel structure high temperature resistant aerogel is placed in a grinding and screening device for crushing and screening to obtain high temperature resistant aerogel particles with a particle size of less than 10 μm.

[0067] (2) Weigh 40 parts of ceramic fiber (the mass ratio of mullite microfiber and magnesium aluminum spinel nanofiber is 1:3), 20 parts of high temperature resistant aerogel particles (the mass ratio of high temperature resistant aerogel particles to ceramic fiber is 1:2), 1.33 parts of silicon carbide whiskers (the mass ratio of silicon carbide whiskers to high temperature resistant aerogel particles is 1:15) and 2 parts of boron nitride nanosheets (the mass ratio of boron nitride nanosheets to ceramic fiber is 1:20) and place them in an aqueous solution containing 1 wt% foaming agent sodium dodecylbenzenesulfonate and 0.5 wt% sizing agent (0.4 wt% gellan gum and 0.1 wt% hydroxypropyl methylcellulose), and quickly stir to disperse into a slurry.

[0068] (3) The above slurry was placed in a plate and frame device for rapid pressure filtration and shaping. The pressure of the pressure filtration was 0.8 MPa and the filtration time was 3 min. Then the slurry and the plate and frame device were placed in an oven for normal pressure drying. The drying temperature was 70℃ and the drying time was 2 h. Then it was rapidly freeze-dried. The freeze-drying temperature was -28℃ and the freeze-drying time was 12 h to obtain the aerogel composite material.

[0069] Comparative Example 6 (1) The spinel structure high temperature resistant aerogel is placed in a grinding and screening device for crushing and screening to obtain high temperature resistant aerogel particles with a particle size of less than 10 μm.

[0070] (2) Weigh 40 parts of ceramic fiber (the mass ratio of mullite microfiber and magnesium aluminum spinel nanofiber is 1:3), 20 parts of high temperature resistant aerogel particles (the mass ratio of high temperature resistant aerogel particles to ceramic fiber is 1:2), 1.33 parts of silicon carbide whiskers (the mass ratio of silicon carbide whiskers to high temperature resistant aerogel particles is 1:15) and 2 parts of boron nitride nanosheets (the mass ratio of boron nitride nanosheets to ceramic fiber is 1:20) and place them in an aqueous solution containing 1 wt% foaming agent sodium dodecylbenzenesulfonate and 0.5 wt% sizing agent (0.4 wt% gellan gum and 0.1 wt% hydroxypropyl methylcellulose), and quickly stir to disperse into a slurry.

[0071] (3) The above slurry was placed in a plate and frame device for rapid pressure filtration and shaping. The pressure of the pressure filtration was 0.8 MPa and the filtration time was 3 min. Then the slurry was connected to the plate and frame device and pre-frozen in liquid nitrogen for 30 min. Then it was rapidly freeze-dried at a temperature of -28℃ for 12 h to obtain a flexible composite material to be calcined. Finally, it was calcined at 900℃ for 12 h to obtain an aerogel composite material.

[0072] Comparative Example 7 (1) The spinel structure high temperature resistant aerogel is placed in a grinding and screening device for crushing and screening to obtain high temperature resistant aerogel particles with a particle size of less than 10 μm.

[0073] (2) Weigh 40 parts of ceramic fiber (the mass ratio of alumina microfiber and zirconium nanofiber is 1:3), 20 parts of high temperature resistant aerogel particles (the mass ratio of high temperature resistant aerogel particles to ceramic fiber is 1:2), 1.33 parts of silicon carbide whiskers (the mass ratio of silicon carbide whiskers to high temperature resistant aerogel particles is 1:15) and 2 parts of boron nitride nanosheets (the mass ratio of boron nitride nanosheets to ceramic fiber is 1:20) and place them in an aqueous solution containing 1 wt% foaming agent sodium dodecylbenzenesulfonate and 0.5 wt% sizing agent (0.4 wt% gellan gum and 0.1 wt% hydroxypropyl methylcellulose), and quickly stir to disperse into a slurry.

[0074] (3) The above slurry was placed in a plate and frame device for rapid pressure filtration and shaping. The pressure of the pressure filtration was 0.8 MPa and the filtration time was 3 min. Then the slurry and the plate and frame device were placed in an oven for normal pressure drying. The drying temperature was 70℃ and the drying time was 2 h. Then it was rapidly freeze-dried. The freeze-drying temperature was -28℃ and the freeze-drying time was 12 h to obtain the flexible composite material to be calcined. Finally, it was calcined at 900℃ for 12 h to obtain the aerogel composite material.

[0075] Comparative Example 8 (1) The spinel structure high temperature resistant aerogel is placed in a grinding and screening device for crushing and screening to obtain high temperature resistant aerogel particles with a particle size of less than 10 μm.

[0076] (2) Weigh 40 parts of ceramic fiber (the mass ratio of mullite microfiber and magnesium aluminum spinel nanofiber is 1:3), 5 parts of high temperature resistant aerogel particles (the mass ratio of high temperature resistant aerogel particles to ceramic fiber is 1:8), 0.33 parts of silicon carbide whiskers (the mass ratio of silicon carbide whiskers to high temperature resistant aerogel particles is 1:15) and 2 parts of boron nitride nanosheets (the mass ratio of boron nitride nanosheets to ceramic fiber is 1:20) and place them in an aqueous solution containing 1 wt% foaming agent sodium dodecylbenzenesulfonate and 0.5 wt% sizing agent (0.4 wt% gellan gum and 0.1 wt% hydroxypropyl methylcellulose), and quickly stir to disperse into a slurry.

[0077] (3) The above slurry was placed in a plate and frame device for rapid pressure filtration and shaping. The pressure of the pressure filtration was 0.8 MPa and the filtration time was 3 min. Then the slurry and the plate and frame device were placed in an oven for normal pressure drying. The drying temperature was 70℃ and the drying time was 2 h. Then it was rapidly freeze-dried. The freeze-drying temperature was -28℃ and the freeze-drying time was 12 h to obtain the flexible composite material to be calcined. Finally, it was calcined at 900℃ for 12 h to obtain the aerogel composite material.

[0078] Comparative Example 9 (1) The spinel structure high temperature resistant aerogel is placed in a grinding and screening device for crushing and screening to obtain high temperature resistant aerogel particles with a particle size of less than 10 μm.

[0079] (2) Weigh 40 parts of ceramic fiber (mullite microfiber), 20 parts of high-temperature resistant aerogel particles (the mass ratio of high-temperature resistant aerogel particles to ceramic fiber is 1:2), 1.33 parts of silicon carbide whiskers (the mass ratio of silicon carbide whiskers to high-temperature resistant aerogel particles is 1:15) and 2 parts of boron nitride nanosheets (the mass ratio of boron nitride nanosheets to ceramic fiber is 1:20) and place them in an aqueous solution containing 1 wt% foaming agent sodium dodecylbenzenesulfonate and 0.5 wt% sizing agent (0.4 wt% gellan gum and 0.1 wt% hydroxypropyl methylcellulose), and quickly stir to disperse into a slurry.

[0080] (3) The above slurry was placed in a plate and frame device for rapid pressure filtration and shaping. The pressure of the pressure filtration was 0.8 MPa and the filtration time was 3 min. Then the slurry and the plate and frame device were placed in an oven for normal pressure drying. The drying temperature was 70℃ and the drying time was 2 h. Then it was rapidly freeze-dried. The freeze-drying temperature was -28℃ and the freeze-drying time was 12 h to obtain the flexible composite material to be calcined. Finally, it was calcined at 900℃ for 12 h to obtain the aerogel composite material.

[0081] Comparative Example 10 (1) The spinel structure high temperature resistant aerogel is placed in a grinding and screening device for crushing and screening to obtain high temperature resistant aerogel particles with a particle size of less than 10 μm.

[0082] (2) Weigh 40 parts of ceramic fiber (magnesium aluminum spinel nanofiber), 20 parts of high temperature resistant aerogel particles (the mass ratio of high temperature resistant aerogel particles to ceramic fiber is 1:2), 1.33 parts of silicon carbide whiskers (the mass ratio of silicon carbide whiskers to high temperature resistant aerogel particles is 1:15) and 2 parts of boron nitride nanosheets (the mass ratio of boron nitride nanosheets to ceramic fiber is 1:20) and place them in an aqueous solution containing 1 wt% foaming agent sodium dodecylbenzenesulfonate and 0.5 wt% sizing agent (0.4 wt% gellan gum and 0.1 wt% hydroxypropyl methylcellulose), and quickly stir to disperse into a slurry.

[0083] (3) The above slurry was placed in a plate and frame device for rapid pressure filtration and shaping. The pressure of the pressure filtration was 0.8 MPa and the filtration time was 3 min. Then the slurry and the plate and frame device were placed in an oven for normal pressure drying. The drying temperature was 70℃ and the drying time was 2 h. Then it was rapidly freeze-dried. The freeze-drying temperature was -28℃ and the freeze-drying time was 12 h to obtain the flexible composite material to be calcined. Finally, it was calcined at 900℃ for 12 h to obtain the aerogel composite material.

[0084] Comparative Example 11 (1) The spinel structure high temperature resistant aerogel is placed in a grinding and screening device for crushing and screening to obtain high temperature resistant aerogel particles with a particle size of less than 10 μm.

[0085] (2) Weigh 40 parts of ceramic fiber (the mass ratio of mullite microfiber and magnesium aluminum spinel nanofiber is 1:3), 20 parts of high temperature resistant aerogel particles (the mass ratio of high temperature resistant aerogel particles to ceramic fiber is 1:2), 1.33 parts of silicon carbide whiskers (the mass ratio of silicon carbide whiskers to high temperature resistant aerogel particles is 1:15) and 2 parts of boron nitride nanosheets (the mass ratio of boron nitride nanosheets to ceramic fiber is 1:20) and place them in an aqueous solution containing 1 wt% foaming agent sodium dodecylbenzenesulfonate and 0.5 wt% sizing agent (gellan gum), and quickly stir and disperse them into a slurry.

[0086] (3) The above slurry was placed in a plate and frame device for rapid pressure filtration and shaping. The pressure of the pressure filtration was 0.8 MPa and the filtration time was 3 min. Then the slurry and the plate and frame device were placed in an oven for normal pressure drying. The drying temperature was 70℃ and the drying time was 2 h. Then it was rapidly freeze-dried. The freeze-drying temperature was -28℃ and the freeze-drying time was 12 h to obtain the flexible composite material to be calcined. Finally, it was calcined at 900℃ for 12 h to obtain the aerogel composite material.

[0087] Comparative Example 12 (1) The spinel structure high temperature resistant aerogel is placed in a grinding and screening device for crushing and screening to obtain high temperature resistant aerogel particles with a particle size of less than 10 μm.

[0088] (2) Weigh 40 parts of ceramic fiber (the mass ratio of mullite microfiber and magnesium aluminum spinel nanofiber is 1:3), 20 parts of high temperature resistant aerogel particles (the mass ratio of high temperature resistant aerogel particles to ceramic fiber is 1:2), 1.33 parts of silicon carbide whiskers (the mass ratio of silicon carbide whiskers to high temperature resistant aerogel particles is 1:15) and 2 parts of boron nitride nanosheets (the mass ratio of boron nitride nanosheets to ceramic fiber is 1:20) and place them in an aqueous solution containing 1 wt% foaming agent sodium dodecylbenzenesulfonate and 0.5 wt% sizing agent (hydroxypropyl methylcellulose), and quickly stir and disperse them into a slurry.

[0089] (3) The above slurry was placed in a plate and frame device for rapid pressure filtration and shaping. The pressure of the pressure filtration was 0.8 MPa and the filtration time was 3 min. Then the slurry and the plate and frame device were placed in an oven for normal pressure drying. The drying temperature was 70℃ and the drying time was 2 h. Then it was rapidly freeze-dried. The freeze-drying temperature was -28℃ and the freeze-drying time was 12 h to obtain the flexible composite material to be calcined. Finally, it was calcined at 900℃ for 12 h to obtain the aerogel composite material.

[0090] Comparative Example 13 (1) The spinel structure high temperature resistant aerogel is placed in a grinding and screening device for crushing and screening to obtain high temperature resistant aerogel particles with a particle size of less than 10 μm.

[0091] (2) Weigh 40 parts of ceramic fiber (the mass ratio of mullite microfiber and magnesium aluminum spinel nanofiber is 1:3), 20 parts of high temperature resistant aerogel particles (the mass ratio of high temperature resistant aerogel particles to ceramic fiber is 1:2), and 1.33 parts of silicon carbide whiskers (the mass ratio of silicon carbide whiskers to high temperature resistant aerogel particles is 1:15) and place them in an aqueous solution containing 1 wt% foaming agent sodium dodecylbenzenesulfonate and 0.5 wt% sizing agent (0.4 wt% gellan gum and 0.1 wt% hydroxypropyl methylcellulose), and quickly stir to disperse into a slurry.

[0092] (3) The above slurry was placed in a plate and frame device for rapid pressure filtration and shaping. The pressure of the pressure filtration was 0.8 MPa and the filtration time was 3 min. Then the slurry and the plate and frame device were placed in an oven for normal pressure drying. The drying temperature was 70℃ and the drying time was 2 h. Then it was rapidly freeze-dried. The freeze-drying temperature was -28℃ and the freeze-drying time was 12 h to obtain the flexible composite material to be calcined. Finally, it was calcined at 900℃ for 12 h to obtain the aerogel composite material.

[0093] The thermal conductivity and tensile strength at 1500℃ of the materials prepared in each embodiment and comparative example of the present invention were measured. The specific values ​​are shown in Table 1. It can be seen that the comprehensive performance of the materials prepared in each embodiment of the present invention is much greater than that of the comparative examples.

[0094] Table 1 The parts of this invention not described in detail are techniques known to those skilled in the art.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a flexible high-temperature resistant aerogel composite material, characterized in that, The method includes the following steps: (1) The high-temperature resistant aerogel is crushed and sieved to obtain high-temperature resistant aerogel particles; (2) The high-temperature resistant aerogel particles, silicon carbide whiskers, boron nitride nanosheets and ceramic fibers are placed in an aqueous solution containing a foaming agent and a setting agent and stirred evenly to obtain a slurry; the ceramic fibers are magnesium aluminum spinel nanofibers and mullite microfibers; (3) The slurry is filtered by pressure, and then dried by normal pressure, freeze-dried and calcined in sequence to obtain a flexible high-temperature resistant aerogel composite material.

2. The preparation method according to claim 1, characterized in that: The particle size of the high-temperature resistant aerogel particles is no greater than 10 μm.

3. The preparation method according to claim 1, characterized in that: The mass ratio of the high-temperature resistant aerogel particles to the ceramic fibers is 1:(1~5); and / or The mass ratio of the mullite microfiber to the magnesium aluminum spinel nanofiber is (1~2):(1~3).

4. The preparation method according to claim 1, characterized in that: The mass ratio of the silicon carbide whiskers to the high-temperature resistant aerogel particles is 1:(10~20); and / or The mass ratio of the boron nitride nanosheets to the ceramic fibers is 1:(20~30).

5. The preparation method according to claim 1, characterized in that: The foaming agent is a surfactant, preferably one or more of sodium dodecylbenzenesulfonate, sodium dodecyl sulfonate, and dodecyltrimethylammonium bromide; and / or The setting agent is gellan gum and hydroxypropyl methylcellulose, preferably, the mass ratio of gellan gum to hydroxypropyl methylcellulose is (2~4):

1.

6. The preparation method according to claim 1, characterized in that: The aqueous solution contains a foaming agent at a mass percentage of 0.01-10%, preferably 0.05-2%; and / or The aqueous solution contains a shaping agent at a mass percentage of 0.5-3%.

7. The preparation method according to claim 1, characterized in that: The pressure of the filter press is 0.5~1MPa.

8. The preparation method according to claim 1, characterized in that: The temperature for atmospheric pressure drying is 50~90℃; and / or The calcination temperature is 600~1000℃.

9. The preparation method according to any one of claims 1 to 8, characterized in that: The high-temperature resistant aerogel is a spinel-structured high-temperature resistant aerogel.

10. A flexible high-temperature resistant aerogel composite material prepared by any one of claims 1 to 9.

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