Aluminum-silicon-yttrium ternary aerogel composite and method for preparing the same

Abstract

The application discloses a preparation method of aluminum-silicon-yttrium ternary aerogel composite material and the aluminum-silicon-yttrium ternary aerogel composite material prepared by the method. The preparation method of the aluminum-silicon-yttrium ternary aerogel composite material comprises the following steps: performing sol immersion on a support body to obtain an immersed support body; wherein the sol comprises a silicon sol and an aluminum-yttrium sol; performing gelation treatment on the immersed support body to obtain a composite aluminum-yttrium-silicon gel support body; and performing aging and drying on the composite aluminum-yttrium-silicon gel support body to obtain the aluminum-silicon-yttrium ternary aerogel composite material. The prepared aluminum-silicon-yttrium ternary aerogel composite material has high-temperature stability, the thermal conductivity is less than or equal to 0.105 W / m.k at 1200 DEG C, and the volume shrinkage rate is 4-8% of the original volume after 1200 DEG C heat treatment for 30 min.

Description

Technical Field

[0001] This invention relates to the field of aerogel composite materials technology, and more specifically to an aluminum-silicon-yttrium ternary aerogel composite material and its preparation method. Background Technology

[0002] Aerogels are low-density porous solid materials with excellent properties such as high specific surface area, low density, high porosity, and high catalytic efficiency, leading to their widespread application. Currently, the most commonly used aerogels on the market include silica aerogels. However, their three-dimensional network nanostructure is prone to collapse at temperatures above 800℃, resulting in reduced porosity and a significant decrease or even loss of thermal insulation, catalytic performance, and strength, severely limiting their application at high temperatures. Therefore, existing technologies typically prepare aerogel composites by combining aerogels with aluminum gels and fiber matrices, improving strength while retaining most of the excellent properties of aerogels. However, this method uses expensive gel initiators, which do not meet market demands; furthermore, at temperatures above 1000℃, silica aerogels undergo a phase transition and volume shrinkage, leading to internal collapse and reduced thermal insulation performance.

[0003] Therefore, providing an aerogel composite material with high porosity, good thermal insulation performance, high strength and low cost at high temperatures has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0004] The purpose of this invention is to solve the above-mentioned problems by proposing a method for preparing an aluminum-silicon-yttrium ternary aerogel composite material. The prepared aluminum-silicon-yttrium ternary aerogel composite material has high-temperature stability, with a thermal conductivity ≤0.105W / m·k at 1200℃ and a volume shrinkage rate of 4-8% of the original volume after heat treatment at 1200℃ for 30 min; preferably, the thermal conductivity ≤0.065W / m·k at 1200℃ and the volume shrinkage rate of 4-6% of the original volume after heat treatment at 1200℃ for 30 min.

[0005] To achieve the above objectives, according to one aspect of the present invention, a method for preparing an aluminum-silicon-yttrium ternary aerogel composite material is provided, wherein a support is impregnated with a sol to obtain an impregnated support; wherein the sol includes silica sol and aluminum-yttrium sol; and the impregnated support is subjected to a gelation treatment to obtain a composite aluminum-yttrium-silicon gel support.

[0006] The composite aluminum-yttrium-silicon gel support is aged and dried to obtain the aluminum-silicon-yttrium ternary aerogel composite material.

[0007] Compared with existing technologies, its advantages lie in the gelation of aluminum, yttrium, and silica sol impregnated in the support, achieving uniform dispersion of aluminum-silicon-yttrium ternary aerogel within the support and avoiding uniform dispersion. By introducing aluminum aerogel onto the silica aerogel base, the collapse problem of silica aerogel above 800℃ is avoided. The introduction of yttrium aerogel avoids the series of phase transformations that occur in alumina aerogel above 1000℃, forming the α-Al₂O₃ phase, thus preventing shrinkage of the aluminum aerogel. This results in an aluminum-silicon-yttrium ternary aerogel composite material with a thermal conductivity of ≤0.105 W / m·K at 1200℃, and a volume shrinkage rate of 5-8% of the original volume after heat treatment at 1200℃ for 30 min.

[0008] Furthermore, the preparation method of the aluminum-silicon-yttrium ternary aerogel composite material involves impregnating the support with aluminum, yttrium, and silica sol as follows: impregnating the support with a mixed aluminum, yttrium, and silica sol; or, impregnating the support in stages, impregnating the support with aluminum sol and silica sol separately.

[0009] Furthermore, the sol-gel impregnation process includes mixed impregnation or stepwise impregnation.

[0010] The mixed impregnation includes: mixing the silica sol and aluminum-yttrium sol to obtain a mixed sol; and impregnating the support with the mixed sol to obtain the impregnated support.

[0011] The stepwise impregnation process is as follows: the support is impregnated with silica sol, and then impregnated with aluminum-yttrium sol. After impregnation, the impregnated support is obtained.

[0012] Furthermore, the preparation process of the mixed sol is as follows:

[0013] The silica alkoxide is dissolved in an alcohol-water mixed solvent, the solution temperature is adjusted to 30-55℃, and then an acidic catalyst is added to adjust the pH value to obtain silica sol.

[0014] Aluminum and yttrium precursors were dissolved in an alcohol-water mixed solvent, the solution temperature was adjusted to 30-55℃, and then an acidic catalyst was added to adjust the pH value to obtain aluminum-yttrium sol.

[0015] The mixed sol was obtained by mixing silica sol and aluminum-yttrium sol.

[0016] Wherein, the volume ratio of alcohol to water in the alcohol-water mixed solvent is (2-4):1;

[0017] The concentration of the silanol solution is 0.5-1.5 mol / L; the pH of the silica sol is 2-5; the concentration of the silanol solution is the concentration of the silanol in the solution obtained after dissolving the silanol in an alcohol-water mixed solvent.

[0018] The acidic catalyst is one of hydrochloric acid, nitric acid, acetic acid, citric acid, and hydrofluoric acid;

[0019] The concentration of the aluminum precursor solution is 0.5-1.5 mol / L, and the concentration of the yttrium precursor solution is 0.02-0.06 mol / L; the pH of the aluminum-yttrium mixed sol is 2-5; the concentration of the aluminum precursor solution is the concentration of the aluminum precursor in the solution obtained after dissolving the aluminum and yttrium precursors in an alcohol-water mixed solvent; the concentration of the yttrium precursor solution is the concentration of the yttrium precursor in the solution obtained after dissolving the aluminum and yttrium precursors in an alcohol-water mixed solvent; the aluminum precursor is aluminum chloride hexahydrate or aluminum nitrate nonahydrate, and the yttrium precursor is yttrium nitrate hexahydrate or yttrium chloride hexahydrate.

[0020] Furthermore, after placing the support in the mold, it is placed into a vacuum impregnation tank. Under negative pressure, the mixed sol is drawn into the vacuum impregnation tank to impregnate the support, thus obtaining the impregnated support.

[0021] The advantage of the previous step is that it enables the uniform impregnation of the evenly mixed aluminum, yttrium, and silicon sol into the interior and surface of the support body in one step.

[0022] Furthermore, the gelation process includes: controlling the temperature of the first gel initiator at 30-60°C, and then, under negative pressure, drawing it into a vacuum impregnation tank containing the impregnated support for gelation to obtain a composite aluminum-yttrium-silicon gel support.

[0023] The first gel initiator includes one or more of ethylene oxide, propylene oxide, and butane oxide;

[0024] The gel treatment time is 3-4 hours, and the molar ratio of the first gel initiator, silanol salt, aluminum precursor, and yttrium precursor is (25-40):(1-5):(5-20):(0.5-5).

[0025] The beneficial effect of the previous step is that by controlling the temperature of the first gel initiator, the molar ratio of the first gel initiator to the silanol, aluminum precursor, and yttrium precursor, and the solution concentrations of the silanol, aluminum precursor, and yttrium precursor, it is beneficial to achieve uniform gelation of the aluminum, yttrium, and silicon mixed sol by the first gel initiator.

[0026] Furthermore, in the stepwise impregnation process, the silica sol is prepared through the following steps:

[0027] The silica alkoxide is dissolved in an alcohol-water mixed solvent, the solution temperature is adjusted to 60-80℃, and then an acidic catalyst is added to adjust the pH value to obtain silica sol.

[0028] The aluminum-yttrium sol is prepared by the following steps: dissolving aluminum precursor and yttrium precursor in an alcohol-water mixed solvent, adjusting the solution temperature to 80-90℃, and then adding an acidic catalyst to adjust the pH value to obtain aluminum-yttrium sol;

[0029] Wherein, the volume ratio of alcohol to water in the alcohol-water mixed solvent is (0.5-1.8):1;

[0030] The concentration of the silanol solution is 0.5-1.0 mol / L; the pH of the silica sol is 2-3;

[0031] The concentration of the aluminum precursor solution is 1-1.5 mol / L, and the concentration of the yttrium precursor solution is 0.02-0.04 mol / L; the pH of the aluminum-yttrium sol is 3-5.

[0032] Furthermore, the stepwise impregnation process and gelation treatment include: placing the support in a mold and then placing it in a vacuum impregnation tank; under negative pressure, drawing silica sol into the vacuum impregnation tank to impregnate the support, thereby obtaining a support impregnated with silica sol.

[0033] Under negative pressure, the second gel initiator is drawn into the vacuum impregnation tank to perform primary gelation on the support after silica sol impregnation, and the support after primary gelation is obtained.

[0034] Aluminum-yttrium sol was drawn into a vacuum impregnation tank under negative pressure to impregnate the initially gelled support, resulting in an aluminum-yttrium sol-impregnated support.

[0035] Under negative pressure, the first gel initiator is drawn into a vacuum impregnation tank to perform secondary gelation on the support after impregnation with aluminum-yttrium sol, thereby obtaining a composite aluminum-yttrium-silicon gel support.

[0036] Furthermore, the second gel initiator includes one or more of ammonia, tetramethylammonium hydroxide, and dimethylaminoethanol; the first gel initiator includes one or more of ethylene oxide, propylene oxide, and butane oxide.

[0037] The beneficial effect of the previous step is that, through the stepwise impregnation, the amount of the first gel initiator added is significantly reduced. Without stepwise gelation, the aluminum-yttrium-silicon mixed sol would require a large amount of the first gel initiator. Stepwise gelation allows for partial gelation with a small amount of the second gel initiator after impregnating the silica sol, followed by impregnation of the aluminum-yttrium mixed sol, and then further gelation with a small amount of the first gel initiator. This significantly reduces the amount of gel initiator used, and the cost of the second gel initiator is significantly lower than that of the first gel initiator, thus significantly reducing costs.

[0038] Controlling the pH of the silica sol to be low is beneficial to improving its catalytic efficiency. However, to avoid partial gelation and solidification of the silica sol or high pH, ​​which would be detrimental to the subsequent mixing of the aluminum-yttrium mixed sol with the silica sol, the concentration of the silanol solution is reduced to 0.5-1.0 mol / L, and the amount of water in the alcohol-water mixed solvent is also reduced. At the same time, the temperature of the silica sol and the aluminum-yttrium mixed sol is controlled to be relatively high to stabilize the sol activity and avoid reducing the initiation efficiency of the gel initiator.

[0039] The high concentration of the aluminum precursor solution (1-1.5 mol / L) is beneficial for improving the initiation efficiency of the first gel initiator and also helps to reduce the efficiency of subsequent drying and supercritical drying.

[0040] Furthermore, the temperature of the second gel initiator is 60-80℃, and the time for the second gel initiator to perform primary gelation of the silica sol impregnated on the support is 0.5-2h; the gelation time of the primary gelation is 0.5-2h.

[0041] The temperature of the first gel initiator is 60-80℃, and the gelation time of the first gel initiator on the support impregnated with silica sol and aluminum-yttrium mixed sol is 1-2h; the molar ratio of the first gel initiator, silanol, second gel initiator, aluminum precursor, and yttrium precursor is (10-20):(0.05-3):(1-5):(5-20):(0.5-5); the gelation time of the secondary gelation is 1-2h; and / or, the composite aluminum-yttrium-silicon gel support is aged at a temperature of 30-60℃ for 23-25h, with solvent replacement 2-4 times, each time for 11.5-12.5h, and then supercritical drying is performed;

[0042] The supercritical drying steps are as follows: using ethanol as the drying medium, the composite aluminum-yttrium-silicon gel support is placed in a supercritical drying vessel, and the temperature is raised to 260-280℃ under a nitrogen atmosphere and a pressure of 3-4 MPa. Then the pressure is raised to 8-10 MPa and maintained for 1-3 hours.

[0043] Then, exhaust pressure is reduced at a rate of 20-100 kPa / min, allowing it to naturally cool to room temperature.

[0044] The beneficial effect of the previous step is that aging at 30-60℃ further achieves cross-linking within the gel, improving the internal porosity and strength of the finished aerogel.

[0045] According to another aspect of the present invention, an aluminum-silicon-yttrium ternary aerogel composite material is provided, which is prepared according to the preparation method described above.

[0046] Compared with the prior art, its beneficial effect is that it solves the above problems by inventing a method for preparing an aluminum-silicon-yttrium ternary aerogel composite material. The prepared aluminum-silicon-yttrium ternary aerogel composite material has high temperature stability, with a thermal conductivity of ≤0.105W / m·k at 1200℃ and a volume shrinkage rate of 4-8% of the original volume after heat treatment at 1200℃ for 30 min; preferably, the thermal conductivity of ≤0.065W / m·k at 1200℃ and the volume shrinkage rate of 4-6% of the original volume after heat treatment at 1200℃ for 30 min. Detailed Implementation

[0047] To better understand the technical solution of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0048] Example 1:

[0049] This embodiment provides a method for preparing an aluminum-silicon-yttrium ternary aerogel composite material, comprising the following steps: impregnating a support with aluminum, yttrium, and silica sol;

[0050] The specific steps for impregnating the support with a mixed sol of aluminum, yttrium, and silicon include:

[0051] Preparation of aluminum, yttrium, and silicon mixed sol:

[0052] Dissolve the silanol salt in an alcohol-water mixed solvent, adjust the solution temperature to 43℃, and then...

[0053] An acidic catalyst was added to adjust the pH value to obtain a silica sol; the concentration of the silanol solution was 1.0 mol / L; the pH of the silica sol was 3.5.

[0054] An aluminum precursor and a yttrium precursor were dissolved in an alcohol-water mixed solvent, and the solution temperature was adjusted to 43°C. Then, an acidic catalyst was added to adjust the pH value to obtain an aluminum-yttrium mixed sol. The concentration of the aluminum precursor solution was 1.0 mol / L, and the concentration of the yttrium precursor solution was 0.04 mol / L. The pH of the aluminum-yttrium mixed sol was 3.5.

[0055] The alcohol-water mixed solvent has an alcohol-to-water volume ratio of 3:1; the acidic catalyst is hydrochloric acid; the aluminum precursor is aluminum chloride hexahydrate, the yttrium precursor is yttrium nitrate hexahydrate; and the alcohol is ethanol.

[0056] A mixed sol was obtained by mixing silica sol with aluminum-yttrium mixed sol;

[0057] The support is placed in a mold and then placed in a vacuum impregnation tank. The mixed sol is then drawn into the vacuum impregnation tank under negative pressure to impregnate the support with the mixed sol.

[0058] The aluminum, yttrium, and silica sol impregnated with the support were gelled to obtain a composite aluminum-yttrium-silica gel support;

[0059] A first gel initiator is prepared; the first gel initiator includes ethylene oxide;

[0060] The first gel initiator was drawn into a vacuum impregnation tank under negative pressure to impregnate the support with a mixed sol of aluminum, yttrium, and silicon to induce gelation; thus obtaining a composite aluminum, yttrium, and silicon gel support.

[0061] The temperature of the first gel initiator is 45°C, the gel time is 3.5 h, and the molar ratio of the first gel initiator, silanol, aluminum precursor, and yttrium precursor is 32:3:12.5:2.8.

[0062] Aluminum-silicon-yttrium ternary aerogel composite material was obtained by aging and drying the composite aluminum, yttrium, and silicon gel support.

[0063] The composite aluminum, yttrium, and silica gel support was aged at 45°C for 24 hours, with solvent replacement performed three times for 12 hours each time, followed by supercritical drying.

[0064] The supercritical drying process is as follows: using ethanol as the drying medium, the composite aluminum, yttrium, and silica gel support is placed in a supercritical drying vessel, and drying begins under a nitrogen atmosphere of 3.5 MPa. The drying temperature reaches 270°C, the pressure is increased to 9 MPa, and the drying is maintained for 2 hours.

[0065] Then, the pressure is reduced by exhausting at a rate of 60 kPa / min; then it is allowed to cool naturally to room temperature.

[0066] Another aspect of this embodiment provides an aluminum-silicon-yttrium ternary aerogel composite material, prepared according to the above-described preparation method;

[0067] The prepared aluminum-silicon-yttrium ternary aerogel composite material has high temperature stability, with a thermal conductivity of 0.09 W / m·k at 1200℃ and a volume shrinkage rate of 7.5% of the original volume after heat treatment at 1200℃ for 30 min.

[0068] Example 2:

[0069] The features that are the same as those in Embodiment 1 will not be repeated here. The features that differ from those in Embodiment 1 are as follows:

[0070] Dissolve the silanol salt in an alcohol-water mixed solvent and adjust the solution temperature to 35℃;

[0071] The concentration of the silanol solution is 1.2 mol / L; the pH of the silica sol is 4.

[0072] The aluminum precursor and yttrium precursor were dissolved in an alcohol-water mixed solvent, and the solution temperature was adjusted to 35°C; the concentration of the aluminum precursor solution was 1.2 mol / L, and the concentration of the yttrium precursor solution was 0.04 mol / L; the pH of the aluminum-yttrium mixed sol was 4.

[0073] The volume ratio of alcohol to water in the alcohol-water mixed solvent is 3.5:1; the alcohol is methanol.

[0074] The acidic catalyst is acetic acid; the aluminum precursor is aluminum nitrate nonahydrate, and the yttrium precursor is yttrium chloride hexahydrate;

[0075] The temperature of the first gel initiator is 50°C, the gel time is 3.8 h, and the molar ratio of the first gel initiator, silanol salt, aluminum precursor, and yttrium precursor is 38:4:14:2.

[0076] The composite aluminum, yttrium, and silica gel support was aged at 50°C for 23.2 hours.

[0077] Then, exhaust pressure is reduced at a rate of 80 kPa / min; then, the pressure is allowed to drop naturally to room temperature.

[0078] Another aspect of this embodiment provides an aluminum-silicon-yttrium ternary aerogel composite material, which is prepared according to the above preparation method; the prepared aluminum-silicon-yttrium ternary aerogel composite material has high temperature stability, with a thermal conductivity of 0.101 W / m·k at 1200℃, and a volume shrinkage rate of 7.2% of the original volume after heat treatment at 1200℃ for 30 min.

[0079] Example 3:

[0080] The features that are the same as those in Embodiment 1 will not be repeated here. The features that differ from those in Embodiment 1 are as follows:

[0081] When impregnating the support in stages, the specific steps for impregnating the support with aluminum, yttrium, and silica sol include:

[0082] A silanol salt was dissolved in an alcohol-water mixed solvent, the solution temperature was adjusted to 70°C, and then an acidic catalyst was added to adjust the pH value to obtain a silica sol; the concentration of the silanol salt solution was 0.7 mol / L; the pH of the silica sol was 2.5.

[0083] An aluminum precursor and a yttrium precursor were dissolved in an alcohol-water mixed solvent, and the solution temperature was adjusted to 85°C. Then, an acidic catalyst was added to adjust the pH value to obtain an aluminum-yttrium mixed sol. The solution concentration of the aluminum precursor was 1.2 mol / L, and the solution concentration of the yttrium precursor was 0.03 mol / L. The pH of the aluminum-yttrium mixed sol was 4.

[0084] The volume ratio of alcohol to water in the alcohol-water mixed solvent is 2.2:1;

[0085] Prepare a first gel initiator and a second gel initiator; the second gel initiator is ammonia.

[0086] The support is placed in a mold and then placed in a vacuum impregnation tank. Silica sol is then drawn into the vacuum impregnation tank under negative pressure to impregnate the support with silica sol.

[0087] Then, the second gel initiator is drawn into the vacuum impregnation tank under negative pressure to impregnate the support with silica sol for primary gelation.

[0088] Then, the aluminum-yttrium mixed sol is drawn into a vacuum impregnation tank under negative pressure to impregnate the primary gelled support with the first gel initiator;

[0089] Then, the first gel initiator was drawn into a vacuum impregnation tank under negative pressure to impregnate the support with silica sol and aluminum-yttrium mixed sol for gelation; thus obtaining a composite aluminum, yttrium, and silica gel support.

[0090] The temperature of the second gel initiator is 70°C, and the time for the second gel initiator to perform primary gelation of the silica sol impregnated on the support is 1 hour.

[0091] The temperature of the first gel initiator is 70°C, and the gelation time of the first gel initiator on the support impregnated with silica sol and aluminum-yttrium mixed sol is 1.5 h; the molar ratio of the first gel initiator, silanol salt, second gel initiator, aluminum precursor, and yttrium precursor is 15:2.8:2:18:3.5.

[0092] Another aspect of this embodiment provides an aluminum-silicon-yttrium ternary aerogel composite material, which is prepared according to the above preparation method; the prepared aluminum-silicon-yttrium ternary aerogel composite material has high temperature stability, with a thermal conductivity of 0.065 W / m·k at 1200℃, and a volume shrinkage rate of 6% of the original volume after heat treatment at 1200℃ for 30 min.

[0093] Example 4:

[0094] The features that are the same as those in Embodiment 1 will not be repeated here. The features that differ from those in Embodiment 1 are as follows:

[0095] When impregnating the support in stages, the specific steps for impregnating the support with aluminum, yttrium, and silica sol include:

[0096] A silanol salt was dissolved in an alcohol-water mixed solvent, the solution temperature was adjusted to 75°C, and then an acidic catalyst was added to adjust the pH value to obtain a silica sol; the concentration of the silanol salt solution was 0.6 mol / L; the pH of the silica sol was 2.2.

[0097] An aluminum precursor and a yttrium precursor were dissolved in an alcohol-water mixed solvent, and the solution temperature was adjusted to 88°C. Then, an acidic catalyst was added to adjust the pH value to obtain an aluminum-yttrium mixed sol. The solution concentration of the aluminum precursor was 1.4 mol / L, and the solution concentration of the yttrium precursor was 0.035 mol / L. The pH of the aluminum-yttrium mixed sol was 3.2.

[0098] The volume ratio of alcohol to water in the alcohol-water mixed solvent is 0.8:1;

[0099] A first gel initiator and a second gel initiator were prepared; the second gel initiator was tetramethylammonium hydroxide.

[0100] The support is placed in a mold and then placed in a vacuum impregnation tank. Silica sol is then drawn into the vacuum impregnation tank under negative pressure to impregnate the support with silica sol.

[0101] Then, the second gel initiator is drawn into the vacuum impregnation tank under negative pressure to impregnate the support with silica sol for primary gelation.

[0102] Then, the aluminum-yttrium mixed sol is drawn into a vacuum impregnation tank under negative pressure to impregnate the primary gelled support with the first gel initiator;

[0103] Then, the first gel initiator was drawn into a vacuum impregnation tank under negative pressure to impregnate the support with silica sol and aluminum-yttrium mixed sol for gelation; thus obtaining a composite aluminum, yttrium, and silica gel support.

[0104] The temperature of the second gel initiator is 78°C, and the time for the second gel initiator to perform primary gelation of the silica sol impregnated on the support is 0.8 h.

[0105] The temperature of the first gel initiator is 78°C, and the gelation time of the first gel initiator on the support impregnated silica sol and aluminum-yttrium mixed sol is 1.2 h; the molar ratio of the first gel initiator, silanol salt, second gel initiator, aluminum precursor, and yttrium precursor is 12:1.5:1.8:15:2.

[0106] Another aspect of this embodiment provides an aluminum-silicon-yttrium ternary aerogel composite material, which is prepared according to the above preparation method; the prepared aluminum-silicon-yttrium ternary aerogel composite material has high temperature stability, with a thermal conductivity of 0.06 W / m·k at 1200℃, and a volume shrinkage rate of 5% of the original volume after heat treatment at 1200℃ for 30 min.

[0107] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, the above-described features have similar functions to (but are not limited to) those disclosed in this application.

Claims

1. A method for preparing an aluminum-silicon-yttrium ternary aerogel composite material, characterized in that, Includes the following steps: The support is impregnated with a sol to obtain the impregnated support; wherein the sol includes silica sol and aluminum-yttrium sol. The impregnated support is subjected to gelation treatment to obtain a composite aluminum-yttrium-silicon gel support; The composite aluminum-yttrium-silicon gel support was aged and dried to obtain the aluminum-silicon-yttrium ternary aerogel composite material. The sol-gel impregnation process includes mixed impregnation; The mixed impregnation includes: mixing the silica sol and aluminum-yttrium sol to obtain a mixed sol; and impregnating the support with the mixed sol to obtain the impregnated support. The preparation process of the mixed sol is as follows: The silica alkoxide is dissolved in an alcohol-water mixed solvent, the solution temperature is adjusted to 30-55℃, and then an acidic catalyst is added to adjust the pH value to obtain silica sol. Aluminum and yttrium precursors were dissolved in an alcohol-water mixed solvent, the solution temperature was adjusted to 30-55℃, and then an acidic catalyst was added to adjust the pH value to obtain aluminum-yttrium sol. The mixed sol was obtained by mixing silica sol and aluminum-yttrium sol. Wherein, the volume ratio of alcohol to water in the alcohol-water mixed solvent is (2-4):1; The concentration of the silanol solution is 0.5-1.5 mol / L; the pH of the silica sol is 2-5; The acidic catalyst is one of hydrochloric acid, nitric acid, acetic acid, citric acid, and hydrofluoric acid; The solution concentration of the aluminum precursor is 0.5-1.5 mol / L, and the solution concentration of the yttrium precursor is 0.02-0.06 mol / L; the pH of the aluminum-yttrium mixed sol is 2-5. The aluminum precursor is aluminum chloride hexahydrate or aluminum nitrate nonahydrate, and the yttrium precursor is yttrium nitrate hexahydrate or yttrium chloride hexahydrate; After the support is placed in the mold, it is put into a vacuum impregnation tank. Under negative pressure, the mixed sol is drawn into the vacuum impregnation tank to impregnate the support, thus obtaining the impregnated support.

2. The preparation method of the aluminum-silicon-yttrium ternary aerogel composite material according to claim 1, characterized in that, The gelation process includes: controlling the temperature of the first gel initiator at 30-60°C, and then, under negative pressure, drawing it into a vacuum impregnation tank containing the impregnated support for gelation to obtain a composite aluminum-yttrium-silicon gel support. The first gel initiator includes one or more of ethylene oxide, propylene oxide, and butane oxide; The gelation treatment time is 3-4 hours, and the molar ratio of the first gel initiator, silanol salt, aluminum precursor, and yttrium precursor is (25-40):(1-5):(5-20):(0.5-5).

3. A method for preparing an aluminum-silicon-yttrium ternary aerogel composite material, characterized in that, Includes the following steps: The support is impregnated with a sol to obtain the impregnated support; wherein the sol includes silica sol and aluminum-yttrium sol. The impregnated support is subjected to gelation treatment to obtain a composite aluminum-yttrium-silicon gel support; The composite aluminum-yttrium-silicon gel support was aged and dried to obtain the aluminum-silicon-yttrium ternary aerogel composite material. The sol-gel impregnation process includes step-by-step impregnation; The stepwise impregnation process is as follows: the support is impregnated with silica sol, and then impregnated with aluminum-yttrium sol. After the impregnation is completed, the impregnated support is obtained. In the stepwise impregnation process, the silica sol is prepared through the following steps: The silica alkoxide is dissolved in an alcohol-water mixed solvent, the solution temperature is adjusted to 60-80℃, and then an acidic catalyst is added to adjust the pH value to obtain silica sol. The aluminum-yttrium sol is prepared by the following steps: dissolving aluminum precursor and yttrium precursor in an alcohol-water mixed solvent, adjusting the solution temperature to 80-90℃, and then adding an acidic catalyst to adjust the pH value to obtain aluminum-yttrium sol; Wherein, the volume ratio of alcohol to water in the alcohol-water mixed solvent is (0.5-1.8):1; The concentration of the silanol solution is 0.5-1.0 mol / L; the pH of the silica sol is 2-3; The solution concentration of the aluminum precursor is 1-1.5 mol / L, and the solution concentration of the yttrium precursor is 0.02-0.04 mol / L; the pH of the aluminum-yttrium sol is 3-5. The stepwise impregnation process and gelation treatment include: After the support is placed in the mold, it is put into the vacuum impregnation tank. Under negative pressure, the silica sol is drawn into the vacuum impregnation tank to impregnate the support, and the support after silica sol impregnation is obtained. Under negative pressure, the second gel initiator is drawn into the vacuum impregnation tank to perform primary gelation on the support after silica sol impregnation, and the support after primary gelation is obtained. Aluminum-yttrium sol was drawn into a vacuum impregnation tank under negative pressure to impregnate the initially gelled support, resulting in an aluminum-yttrium sol-impregnated support. Under negative pressure, the first gel initiator is drawn into a vacuum impregnation tank to perform secondary gelation on the support after impregnation with aluminum-yttrium sol, thereby obtaining a composite aluminum-yttrium-silicon gel support.

4. The preparation method of the aluminum-silicon-yttrium ternary aerogel composite material according to claim 3, characterized in that, The second gel initiator includes one or more of ammonia, tetramethylammonium hydroxide, and dimethylaminoethanol; The first gel initiator includes one or more of ethylene oxide, propylene oxide, and butane oxide.

5. The method for preparing the aluminum-silicon-yttrium ternary aerogel composite material according to claim 4, characterized in that, The temperature of the second gel initiator is 60-80℃, and the time for the second gel initiator to perform primary gelation of the silica sol impregnated on the support is 0.5-2h; the gelation time of the primary gelation is 0.5-2h. The temperature of the first gel initiator is 60-80℃, and the gelation time of the first gel initiator on the support impregnated silica sol and aluminum-yttrium mixed sol is 1-2h; the molar ratio of the first gel initiator, silanol, second gel initiator, aluminum precursor, and yttrium precursor is (10-20):(0.05-3):(1-5):(5-20):(0.5-5); The gelation time for the secondary gelation is 1-2 hours; and / or The composite aluminum-yttrium-silicon gel support was aged at 30-60℃ for 23-25 ​​hours, with solvent replacement 2-4 times, each time for 11.5-12.5 hours, and then supercritical drying was performed. The supercritical drying steps are as follows: using ethanol as the drying medium, the composite aluminum-yttrium-silicon gel support is placed in a supercritical drying vessel, and the temperature is raised to 260-280℃ under a nitrogen atmosphere and a pressure of 3-4 MPa. Then the pressure is raised to 8-10 MPa and maintained for 1-3 hours. Then, exhaust pressure is reduced at a rate of 20-100 kPa / min, allowing it to naturally cool to room temperature.

6. An aluminum-silicon-yttrium ternary aerogel composite material, characterized in that, Prepared according to the preparation method according to any one of claims 1-5.