Ceramic fiber-aluminum silicate oxide composite aerogel and preparation method and application thereof

Abstract

The application discloses a ceramic fiber-aluminum silicon oxide composite aerogel as well as a preparation method and application thereof. The composition of the ceramic fiber-aluminum silicon oxide composite aerogel comprises an aluminum silicon oxide aerogel matrix and a zirconia-silica hollow fiber framework. The composition of the aluminum silicon oxide aerogel matrix comprises aluminum oxide particles and silica particles. The zirconia-silica hollow fiber framework comprises a plurality of layers of zirconia-silica hollow fiber membranes, and the zirconia-silica hollow fiber membranes comprise zirconia-silica hollow fibers. The ceramic fiber-aluminum silicon oxide composite aerogel has the advantages of excellent heat insulation performance, good compression resilience, excellent high-temperature resistance and the like, can be used as a heat insulation, flame-retardant, fireproof and sound-absorbing and noise-reducing material in the fields of new energy vehicles, buildings, chemical engineering, aerospace and the like, and has the advantages of simple preparation method, low production cost, and suitability for large-scale industrial production and application.

Description

Technical Field

[0001] This invention relates to the field of thermal insulation materials technology, specifically to a ceramic fiber-aluminum silicon oxide composite aerogel, its preparation method, and its application. Background Technology

[0002] Ceramic aerogels possess advantages such as high porosity, low density, and low thermal conductivity, making them commonly used lightweight functional materials in fields such as power battery thermal insulation, aerospace thermal protection, and energy-saving insulation in industrial buildings. Currently, ceramic aerogels mainly fall into two categories: 1) Nanoparticle-based ceramic aerogels (e.g., silica aerogels), which contain a three-dimensional network framework structure resembling a "pearl necklace" composed of zero-dimensional nanoparticles. However, due to the limited bonding force between nanoparticles, this type of ceramic aerogel suffers from low mechanical strength, high brittleness, and severe powder shedding; 2) Inorganic ceramic fiber-based ceramic aerogels, which contain a three-dimensional framework constructed from intertwined ceramic fibers. This three-dimensional framework helps buffer thermal stress and prevents the sintering collapse of the aerogel precursor, thus reducing the damage to the aerogel microstructure caused by high-temperature thermal shock. However, this type of ceramic fiber aerogel suffers from a relatively high thermal conductivity. In summary, existing ceramic aerogels all have significant defects, making it difficult to fully meet practical application requirements and greatly limiting their application.

[0003] Therefore, developing a ceramic aerogel with good mechanical properties, excellent thermal insulation properties, and excellent high-temperature resistance is of great significance. Summary of the Invention

[0004] The purpose of this invention is to provide a ceramic fiber-aluminum silicon oxide composite aerogel, its preparation method, and its application.

[0005] The technical solution adopted in this invention is: A ceramic fiber-aluminum-silicon oxide composite aerogel is comprising an aluminum-silicon oxide aerogel matrix and a zirconia-silica hollow fiber skeleton. The aluminum-silicon oxide aerogel matrix comprises aluminum oxide particles and silica particles. The zirconia-silica hollow fiber skeleton comprises a multilayer zirconia-silica hollow fiber membrane, and the zirconia-silica hollow fiber membrane comprises zirconia-silica hollow fibers.

[0006] Preferably, the ceramic fiber-aluminum silicon oxide composite aerogel comprises the following components by mass percentage: Zirconia-silica hollow fiber: 30%–70%; Aluminum oxide particles: 17%–39%; Silica particles: 13%–31%.

[0007] Preferably, the zirconium oxide-silica hollow fiber has an inner diameter of 0.7μm to 1.5μm, an outer diameter of 0.8μm to 2.1μm, and an aspect ratio of 80 to 200:1.

[0008] Preferably, the mass ratio of zirconium oxide to silicon dioxide in the zirconium oxide-silica hollow fiber is 0.8 to 3.5:1.

[0009] Preferably, the particle size of the aluminum oxide particles is 0.1 μm to 0.6 μm.

[0010] Preferably, the particle size of the silica particles is 0.1 μm to 0.6 μm.

[0011] Preferably, the number of layers of the multilayer zirconia-silica hollow fiber membrane included in the zirconia-silica hollow fiber skeleton is 3 to 20.

[0012] Preferably, the density of the zirconium oxide-silica hollow fiber membrane is 40 mg / cm³. 3 ~78mg / cm 3 .

[0013] Preferably, the thickness of the zirconium oxide-silica hollow fiber membrane is 1.7 mm to 2.0 mm.

[0014] Preferably, the zirconium oxide-silica hollow fiber membrane is prepared by a method comprising the following steps: 1) A mixture of silicon source, oxalic acid, ethanol and water is hydrolyzed to prepare a hydrolysate. A zirconium acetate acetic acid solution and a spinning aid are mixed to prepare a zirconium source solution. The hydrolysate and the zirconium source solution are then mixed to prepare a shell solution. 2) The shell solution and liquid core material are added to the liquid supply device of the electrospinning machine, and then electrospinning is performed using a coaxial needle. The coaxial needle is controlled to move back and forth on the surface of the receiver to obtain a fiber membrane. 3) The fiber membrane is immersed in an organic solvent for soaking, then taken out, dried and calcined to obtain a zirconium oxide-silica hollow fiber membrane.

[0015] Preferably, the mass ratio of silicon source, oxalic acid, ethanol and water in step 1) is 1:0.007~0.01:1.2~1.5:0.03~0.3.

[0016] Preferably, the silicon source in step 1) is at least one of tetraethyl orthosilicate, methyltrimethoxysilane, dimethyldimethoxysilane, and 3-aminopropyltriethoxysilane.

[0017] Preferably, the mass ratio of the zirconium acetate acetic acid solution to the spinning aid in step 1) is 50-100:1.

[0018] Preferably, the zirconium acetate in the acetic acid solution of zirconium acetate in step 1) has a mass percentage content of 10% to 16%.

[0019] Preferably, the spinning aid in step 1) is at least one of polyethylene oxide, polyvinylpyrrolidone, and polyvinyl alcohol.

[0020] Preferably, the liquid core material in step 2) is at least one of mineral oil, paraffin oil, and silicone oil.

[0021] Preferably, in step 2), the inner diameter of the inner needle tube of the coaxial needle is 0.3mm to 0.5mm, and the inner diameter of the outer needle tube is 0.9mm to 1.5mm.

[0022] Preferably, the electrospinning in step 2) is carried out at a temperature of 20℃~27℃ and a relative humidity of 40%~50%.

[0023] Preferably, the electrospinning process parameters in step 2) include: a spinning voltage of 15kV to 22kV, a feed rate ratio of liquid core material to shell solution of 0.2 to 0.5:1, a vertical distance between the coaxial needle and the receiver of 10cm to 30cm, a moving speed of the coaxial needle of 1mm / s to 10mm / s, and a spinning time of 3h to 4h.

[0024] Preferably, the organic solvent in step 3) is at least one of cyclohexane, n-hexane, octane, and acetone.

[0025] Preferably, the soaking time in step 3) is 12h to 24h.

[0026] Preferably, the drying in step 3) is carried out at a temperature of 60℃ to 80℃ for a drying time of 2h to 12h.

[0027] Preferably, the calcination in step 3) includes the following operations: controlling the heating rate to rise from room temperature to 700℃ to 1200℃ at a rate of 1℃ / min to 5℃ / min, and holding at that temperature for 1h to 4h.

[0028] Preferably, the calcination in step 3) is carried out in an air atmosphere.

[0029] Preferably, the density of the ceramic fiber-aluminum silicon oxide composite aerogel is 35 mg / cm³. 3 ~40mg / cm 3 The thermal conductivity is 30 mW·m -1 ·K -1 ~40mW·m -1 ·K -1 .

[0030] A method for preparing the ceramic fiber-aluminum silicon oxide composite aerogel as described above includes the following steps: a) Disperse aluminum chloride hexahydrate, silicon source and boric acid in water to obtain aluminum silicate sol; b) Immerse the zirconia-silica hollow fiber membrane in aluminosilicate sol, stack the zirconia-silica hollow fiber membranes layer by layer, and then freeze-dry and calcinate to obtain ceramic fiber-aluminosilicate oxide composite aerogel.

[0031] Preferably, the mass ratio of aluminum chloride hexahydrate, silicon source, boric acid, and water in step a) is 1:2-3:0.1-0.2:30-40.

[0032] Preferably, the silicon source in step a) is at least one of tetraethyl orthosilicate, methyltrimethoxysilane, dimethyldimethoxysilane, and 3-aminopropyltriethoxysilane.

[0033] Preferably, the mass fraction of the aluminum silica sol in step a) is 5% to 20%.

[0034] Preferably, the mass ratio of the zirconium oxide-silica hollow fiber membrane to the aluminosilicate sol in step b) is 1:100-200.

[0035] Preferably, the freeze drying in step b) is carried out under the conditions of a cold trap temperature of -50℃ to -70℃ and a vacuum degree of 1Pa to 5Pa, and the drying time is 24h to 72h.

[0036] Preferably, the calcination in step b) includes the following operations: controlling the heating rate to rise from room temperature to 700℃ to 1200℃ at a rate of 1℃ / min to 5℃ / min, and holding at that temperature for 1h to 4h.

[0037] Preferably, the calcination in step b) is carried out in an air atmosphere.

[0038] Application of a ceramic fiber-aluminum silicon oxide composite aerogel as described above in the preparation of thermal insulation materials, flame retardant materials, or sound absorption and noise reduction materials.

[0039] The technical principle of this invention is as follows: This invention uses zirconia-silica hollow fibers to prepare ceramic aerogels. The combination of zirconia (ZrO2) and silica (SiO2) can improve the mechanical properties of the fibers through phase transformation toughening and grain boundary strengthening. Furthermore, SiO2 can inhibit the phase transformation of ZrO2 under high-temperature conditions, enabling the fibers to maintain a stable tetragonal or cubic crystal structure at high temperatures, further improving the thermal stability of the fibers. Moreover, the interior of the zirconia-silica hollow fibers and the spaces between adjacent fibers are filled with a large amount of air, resulting in a higher porosity for the zirconia-silica hollow fiber membrane. In addition, the pores inside the zirconia-silica hollow fibers can form a bilevel confined space with the nanopores of the aluminosilicate aerogel matrix, making the mean free path of air molecules (70 nm) much larger than the pore size, which helps to hinder heat conduction, thereby effectively reducing the thermal conductivity of the composite aerogel. In addition, hollow fibers have a larger specific surface area and more solid / gas interfaces than solid fibers, which helps to promote multiple reflections of heat radiation inside the composite aerogel, effectively extending the heat conduction path and thus further improving the thermal insulation performance of the composite aerogel.

[0040] The beneficial effects of this invention are: the ceramic fiber-aluminum silicon oxide composite aerogel of this invention has the advantages of excellent thermal insulation performance, good compression resilience and excellent high temperature resistance. It can be used as a thermal insulation, flame retardant and fireproof and sound absorption and noise reduction material in the fields of new energy vehicles, construction, chemical industry and aerospace. Moreover, its preparation method is simple and the production cost is low, making it suitable for large-scale industrial production and application.

[0041] Specifically: 1) The ceramic fiber-aluminum silicon oxide composite aerogel of the present invention contains zirconium oxide-silica hollow fibers, which have higher porosity and lower density than solid ceramic fibers, thus the aerogel has better thermal insulation performance. 2) The ceramic fiber-aluminum silica oxide composite aerogel of the present invention has a layered stacked structure, which exhibits significant anisotropy (including anisotropy of mechanical properties and thermal insulation properties) in the directions parallel and perpendicular to the zirconium oxide-silica hollow fiber membrane. At the same time, it also has excellent mechanical properties and compression resilience (calcination causes the aluminosilicate sol to undergo a ceramicization reaction with the surface of the ZrO2-Al2O3 hollow fiber membrane, thereby firmly bonding the stacked ZrO2-Al2O3 hollow fiber membrane, enhancing the interfacial bonding force between the ZrO2-Al2O3 hollow fiber membranes, forming a composite aerogel with a layered porous structure, which can significantly improve the mechanical properties and compression resilience of the composite aerogel). It is suitable for use as thermal insulation material, flame retardant fireproof material and sound absorption and noise reduction material in the fields of new energy vehicles, construction, chemical industry, aerospace, etc. 3) The density and structure of the ceramic fiber-aluminum silicon oxide composite aerogel of the present invention can be controlled by changing the porosity and stacking number of ZrO2-Al2O3 hollow fiber membrane. The shape and thickness of the composite aerogel can also be adjusted, thereby adjusting and optimizing the thermal insulation and mechanical properties of the composite aerogel. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the structure of the ceramic fiber-aluminum silicon oxide composite aerogel of the present invention.

[0043] Figure 2 This is a SEM image of the zirconium oxide-silica hollow fiber from Example 2.

[0044] Figure 3 This is a physical image of the ceramic fiber-aluminum silicon oxide composite aerogel in Example 2.

[0045] Figure 4 This is an infrared thermal image of the ceramic fiber-aluminum silicon oxide composite aerogel in Example 2.

[0046] Figure 5 The image shows the compressive stress-strain curve of the ceramic fiber-aluminum silicon oxide composite aerogel in Example 2. Detailed Implementation

[0047] The present invention will be further explained and described below with reference to specific embodiments.

[0048] Example 1: A zirconium oxide-silica hollow fiber membrane is prepared by the following method: 1) Tetraethyl orthosilicate, anhydrous oxalic acid, anhydrous ethanol, and deionized water were mixed in a mass ratio of 1:0.007:1.2:0.3 and stirred for 8 hours at a stirring rate of 500 r / min to obtain a hydrolysate. A 15% zirconium acetate acetic acid solution and polyethylene oxide were mixed in a mass ratio of 50:1 and stirred for 8 hours at a stirring rate of 500 r / min to obtain a zirconium source solution. The hydrolysate and the zirconium source solution were mixed in a mass ratio of 1:1 and stirred for 4 hours at a stirring rate of 500 r / min to obtain a shell solution. 2) The shell solution and mineral oil (liquid core material) are vacuum-defoamed and then added to the liquid supply device of the electrospinning machine. Electrospinning is then performed using a coaxial needle at a temperature of 26℃ and a relative humidity of 46%. The coaxial needle is controlled to move back and forth on the surface of the planar receiver. The inner diameter of the inner needle tube of the coaxial needle is 0.4mm and the inner diameter of the outer needle tube is 1.05mm. The process parameters for electrospinning are as follows: spinning voltage is 21kV, the feed rate of the shell solution is 1.2mL / h, the feed rate of the mineral oil is 0.36mL / h, the vertical distance between the coaxial needle and the receiver is 15cm, the moving speed of the coaxial needle is 3mm / s, and the spinning time is 4h to obtain a fiber membrane. 3) The fiber membrane was immersed in cyclohexane for 24 hours, then removed and air-dried naturally, followed by drying at 80℃ for 2 hours. It was then placed in a tube furnace and heated from room temperature to 900℃ at a controlled rate of 2℃ / min under air atmosphere, held at that temperature for 3 hours, and then allowed to cool naturally to room temperature with the furnace to obtain a zirconia-silica hollow fiber membrane (density 47 mg / cm³). 3 (The thickness is 1.8mm).

[0049] Note: The following reactions occur during the preparation of zirconium oxide-silica hollow fiber membranes: .

[0050] A ceramic fiber-aluminum silicon oxide composite aerogel (structural schematic diagram shown) Figure 1 As shown in the table below, its composition is as follows: Table 1. Composition of ceramic fiber-aluminum silicon oxide composite aerogel

[0051] The preparation method of the above-mentioned ceramic fiber-aluminum silicon oxide composite aerogel is as follows: a) Add aluminum chloride hexahydrate, tetraethyl orthosilicate, and boric acid to deionized water. The mass ratio of aluminum chloride hexahydrate, tetraethyl orthosilicate, boric acid, and deionized water is 1:2.17:0.13:33. Stir for 6 hours at a stirring rate of 500 r / min to obtain aluminum silicate sol (mass fraction of 5%). b) The zirconia-silica hollow fiber membrane in this embodiment was cut into squares with a side length of 20 mm and then immersed in aluminosilicate sol. Three square zirconia-silica hollow fiber membranes were stacked layer by layer (with edges aligned and arranged neatly). The mass ratio of the zirconia-silica hollow fiber membrane (total mass of the three membranes) to the aluminosilicate sol was 1:100. After immersion for 30 min, the membranes were rapidly frozen with liquid nitrogen and then placed in a freeze dryer. The cold trap temperature was set to -60°C and the vacuum degree to 5 Pa. The membranes were freeze-dried for 48 h and then placed in a tube furnace. The temperature was controlled at a rate of 2℃ / min under air atmosphere to rise from room temperature to 800℃, held for 1 hour, and then naturally cooled to room temperature in the furnace to obtain ceramic fiber-aluminum silicon oxide composite aerogel (composed of an aluminum silicon oxide aerogel matrix and a zirconia-silica hollow fiber skeleton; the aluminum silicon oxide aerogel matrix is ​​composed of aluminum oxide particles and silica particles; the zirconia-silica hollow fiber skeleton contains 3 layers of zirconia-silica hollow fiber membranes; the zirconia-silica hollow fiber membranes are composed of zirconia-silica hollow fibers).

[0052] Example 2: A zirconium oxide-silica hollow fiber membrane (density 41 mg / cm³) 3 (The thickness is 1.7 mm). Except for adjusting the feed rate of mineral oil from "0.36 mL / h" to "0.48 mL / h" during the preparation process, it is completely the same as in Example 1.

[0053] The scanning electron microscope (SEM) image of the zirconium oxide-silica hollow fiber in this embodiment is shown below. Figure 2 (a and b represent SEM images at different magnifications) as shown.

[0054] Depend on Figure 2 It can be seen that the zirconium oxide-silica hollow fiber membrane has a three-dimensional network structure formed by the interweaving and winding of hollow tubular fibers (with an inner diameter of 0.7μm to 1.5μm, an outer diameter of 0.8μm to 1.7μm, and an aspect ratio of 80 to 170:1).

[0055] A ceramic fiber-aluminum silicon oxide composite aerogel (actual product image shown) Figure 3 As shown in the table below, its composition is as follows: Table 2 Composition of ceramic fiber-aluminum silicon oxide composite aerogel

[0056] The preparation method of the above ceramic fiber-aluminum silicon oxide composite aerogel is basically the same as that of Example 1, except that the zirconium oxide-silica hollow fiber membrane used in this example is used.

[0057] The infrared thermal image of the ceramic fiber-aluminum silicon oxide composite aerogel in this embodiment is shown below. Figure 4 (The temperature change at the top of the ceramic fiber-aluminum silicon oxide composite aerogel observed by infrared thermography on a constant 100℃ heating plate is shown in the figure.) The compressive stress-strain relationship curve is as follows: Figure 5 (The ceramic fiber-aluminum silicon oxide composite aerogel was placed in a universal testing machine for compression performance testing. A single compression-unloading cycle was performed, and the selected compression strains were 20%, 40%, 60%, and 80%, respectively.)

[0058] Depend on Figure 4 It can be seen that the surface temperature of the ceramic fiber-aluminum silicon oxide composite aerogel is 51.9℃ after being placed on a heating plate at a constant 100℃ for 3 minutes. Compared with before heating, the surface temperature rise is only 16℃, indicating that it has good thermal insulation performance.

[0059] Depend on Figure 5 It can be seen that the ceramic fiber-aluminum silicon oxide composite aerogel can withstand multiple compression-unloading cycles with a maximum compressive strain of 80%. When the compressive strain is 80%, the compressive stress is 37.44 kPa, which shows good mechanical properties and compression resilience.

[0060] Example 3: A ceramic fiber-aluminum silicon oxide composite aerogel is identical to the ceramic fiber-aluminum silicon oxide composite aerogel in Example 1, except that the number of zirconium oxide-silica hollow fiber membrane layers is changed from "3 layers" to "5 layers".

[0061] Example 4: A zirconium oxide-silica hollow fiber membrane (density 44 mg / cm³) 3 (The thickness is 1.8 mm). Except for adjusting the mass ratio of hydrolysate and zirconium source solution from "1:1" to "2:1" during the preparation process, it is completely the same as Example 1.

[0062] A ceramic fiber-aluminum silicon oxide composite aerogel has the following composition as shown in the table below: Table 3 Composition of ceramic fiber-aluminum silicon oxide composite aerogel

[0063] The preparation method of the above ceramic fiber-aluminum silicon oxide composite aerogel is basically the same as that of Example 1, except that the zirconium oxide-silica hollow fiber membrane used in this example is used.

[0064] Example 5: A ceramic fiber-aluminum silicon oxide composite aerogel (compared to the ceramic fiber-aluminum silicon oxide composite aerogel in Example 1, the mass percentage of ZrO2-SiO2 hollow fibers is changed from "70%" to "50%", the mass percentage of Al2O3 particles is changed from "17%" to "33%", and the mass percentage of SiO2 particles is changed from "13%" to "17%), is completely identical to Example 1 except that the mass fraction of aluminosilicate sol is adjusted from "5%" to "20%" during preparation.

[0065] Comparative Example 1: A zirconium oxide-silica solid fiber membrane is prepared by the following method: 1) Tetraethyl orthosilicate, anhydrous oxalic acid, anhydrous ethanol, and deionized water were mixed in a mass ratio of 1:0.007:1.2:0.3. The mixture was stirred for 8 hours at a stirring rate of 500 r / min to obtain a hydrolysate. A 15% zirconium acetate acetic acid solution and polyethylene oxide were mixed in a mass ratio of 50:1 and stirred for 8 hours at a stirring rate of 500 r / min to obtain a zirconium source solution. The hydrolysate and the zirconium source solution were mixed in a mass ratio of 1:1 and stirred for 4 hours at a stirring rate of 500 r / min to obtain a spinning solution. 2) The spinning solution is vacuum-defoamed and then added to the liquid supply device of the electrospinning machine. Electrospinning is then performed using a spinning needle at a temperature of 26℃ and a relative humidity of 48%. The spinning needle is controlled to move back and forth on the surface of the planar receiver. The inner diameter of the spinning needle is 1.05mm. The process parameters for electrospinning are as follows: spinning voltage is 21kV, the feed rate of the spinning solution is 1.2mL / h, the vertical distance between the spinning needle and the receiver is 15cm, the moving speed of the spinning needle is 3mm / s, and the spinning time is 3h to obtain a fiber membrane. 3) The fiber membrane was dried at 80℃ for 2 hours, then placed in a tube furnace and heated from room temperature to 900℃ at a controlled heating rate of 2℃ / min under air atmosphere. The temperature was held for 3 hours, and then allowed to cool naturally to room temperature with the furnace to obtain a solid zirconia-silica fiber membrane (density 60 mg / cm³). 3 (The thickness is 1.9mm).

[0066] A ceramic fiber-aluminum silicon oxide composite aerogel has the following composition as shown in the table below: Table 4. Composition of ceramic fiber-aluminum silicon oxide composite aerogel

[0067] The preparation method of the above ceramic fiber-aluminum silicon oxide composite aerogel is basically the same as that of Example 1, except that the zirconium oxide-silica solid fiber membrane used in this comparative example is used.

[0068] Comparative Example 2: An aluminosilicate aerogel is prepared as follows: a) Add aluminum chloride hexahydrate, methyltrimethoxysilane and boric acid to deionized water. The mass ratio of aluminum chloride hexahydrate, methyltrimethoxysilane, boric acid and deionized water is 1:4.34:0.26:66. Stir for 8 hours at a stirring rate of 500 r / min to obtain aluminum silicate sol. b) Add 1 mL of 1 mol / L ammonia solution to 25 g of aluminosilicate sol, stir well, pour into a mold, freeze rapidly with liquid nitrogen, place in a freeze dryer, set the cold trap temperature to -60℃ and the vacuum degree to 5 Pa, freeze dry for 48 h to obtain aluminosilicate aerogel.

[0069] Performance testing: The density and thermal conductivity test results of the ceramic fiber-aluminum silicon oxide composite aerogels in Examples 1-5, the ceramic fiber-aluminum silicon oxide composite aerogel in Comparative Example 1, and the aluminum silicon aerogel in Comparative Example 2 are shown in the table below: Table 5. Test results of density and thermal conductivity

[0070] Note: Thermal conductivity: The thermal conductivity was tested using a thermal conductivity analyzer (Hot Disk TPS 2500S) in accordance with "ISO 22007-2:2008 Determination of thermal conductivity and thermal diffusivity of plastics - Part 2: Instantaneous planar heat source (heating plate) method".

[0071] As shown in Table 5: 1) The density of the ceramic fiber-aluminum silicon oxide composite aerogel in Examples 1-5 is 36.7 mg / cm³. 3 ~38.5mg / cm 3 The thermal conductivity is 34.2 mW·m -1 ·K -1 ~37.9mW·m -1 ·K -1 With low density and thermal conductivity, it has the advantages of excellent thermal insulation performance, good compression resilience and excellent high temperature resistance, making it suitable for use as thermal insulation, flame retardant and fireproof and sound absorption and noise reduction materials in new energy vehicles, construction, chemical industry, aerospace and other fields. 2) Compared with the ceramic fiber-aluminum silicon oxide composite aerogel in Example 1, the feed rate of mineral oil (liquid core material) in Example 2 increased from "0.36 mL / h" to "0.48 mL / h", resulting in an increase in the pore size of the formed zirconium oxide-silica hollow fibers, which in turn reduced the density and thermal conductivity of the ceramic fiber-aluminum silicon oxide composite aerogel. 3) Compared with the ceramic fiber-aluminum silicon oxide composite aerogel in Example 1, the number of stacked layers of the zirconium oxide-silica hollow fiber membrane in Example 3 increased from 3 to 5, which increased the solid-phase thermal conductivity of the fiber and thus increased the thermal conductivity of the ceramic fiber-aluminum silicon oxide composite aerogel. 4) Compared with the ceramic fiber-aluminum silicon oxide composite aerogel in Example 1, the mass ratio of hydrolysate to zirconium source solution in Example 4 was adjusted from "1:1" to "2:1", the proportion of silicon source increased, the thermal conductivity of the fiber solid phase decreased, and the thermal conductivity of the ceramic fiber-aluminum silicon oxide composite aerogel decreased. 5) Compared with the ceramic fiber-aluminum silicon oxide composite aerogel in Example 1, the mass fraction of aluminosilicate sol in the ceramic fiber-aluminosilicate oxide composite aerogel in Example 5 increased from "5%" to "20%". The aluminosilicate sol filled the gaps between the stacked fibers, resulting in an increase in the density of the ceramic fiber-aluminosilicate oxide composite aerogel and an increase in the thermal conductivity. 6) In Comparative Example 1, ZrO2-SiO2 solid fibers were used, and the thermal conductivity of the ceramic fiber-aluminum silicon oxide composite aerogel was significantly increased, indicating that hollow fibers are more conducive to reducing thermal conductivity. 7) No ceramic fibers were used in Comparative Example 2. The aluminosilicate aerogel had a high density and thermal conductivity, low mechanical strength and high brittleness, and the maximum compressive strain could not reach 80% (compression performance test was conducted with reference to Example 2).

[0072] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A ceramic fiber-aluminum silicon oxide composite aerogel, characterized in that, The composition includes an aluminum-silicon oxide aerogel matrix and a zirconia-silica hollow fiber framework; the aluminum-silicon oxide aerogel matrix comprises aluminum oxide particles and silica particles; the zirconia-silica hollow fiber framework comprises a multilayer zirconia-silica hollow fiber membrane; and the zirconia-silica hollow fiber membrane comprises zirconia-silica hollow fibers.

2. The ceramic fiber-aluminum silicon oxide composite aerogel according to claim 1, characterized in that: The ceramic fiber-aluminum silicon oxide composite aerogel comprises the following components by mass percentage: Zirconia-silica hollow fiber: 30%–70%; Aluminum oxide particles: 17%–39%; Silica particles: 13%–31%.

3. The ceramic fiber-aluminum silicon oxide composite aerogel according to claim 1 or 2, characterized in that: The alumina particles have a particle size of 0.1 μm to 0.6 μm; the silica particles have a particle size of 0.1 μm to 0.6 μm; the zirconium oxide-silica hollow fiber has an inner diameter of 0.7 μm to 1.5 μm, an outer diameter of 0.8 μm to 2.1 μm, and an aspect ratio of 80 to 200:1; the mass ratio of zirconium oxide to silica in the zirconium oxide-silica hollow fiber is 0.8 to 3.5:

1.

4. The ceramic fiber-aluminum silicon oxide composite aerogel according to claim 1 or 2, characterized in that: The zirconium oxide-silica hollow fiber membrane is prepared by a method including the following steps: 1) A mixture of silicon source, oxalic acid, ethanol and water is hydrolyzed to prepare a hydrolysate. A zirconium acetate acetic acid solution and a spinning aid are mixed to prepare a zirconium source solution. The hydrolysate and the zirconium source solution are then mixed to prepare a shell solution. 2) The shell solution and liquid core material are added to the liquid supply device of the electrospinning machine, and then electrospinning is performed using a coaxial needle. The coaxial needle is controlled to move back and forth on the surface of the receiver to obtain a fiber membrane. 3) The fiber membrane is immersed in an organic solvent for soaking, then taken out, dried and calcined to obtain a zirconium oxide-silica hollow fiber membrane.

5. The ceramic fiber-aluminum silicon oxide composite aerogel according to claim 4, characterized in that: In step 1), the mass ratio of silicon source, oxalic acid, ethanol, and water is 1:0.007-0.01:1.2-1.5:0.03-0.3; the silicon source in step 1) is at least one of tetraethyl orthosilicate, methyltrimethoxysilane, dimethyldimethoxysilane, and 3-aminopropyltriethoxysilane; the mass ratio of zirconium acetate acetic acid solution and spinning aid in step 1) is 50-100:1; the zirconium acetate content in the zirconium acetate acetic acid solution in step 1) is 10%-16% by mass; and the spinning aid in step 1) is at least one of polyethylene oxide, polyvinylpyrrolidone, and polyvinyl alcohol.

6. The ceramic fiber-aluminum silicon oxide composite aerogel according to claim 4, characterized in that: Step 2) The liquid core material is at least one of mineral oil, paraffin oil, and silicone oil; Step 2) The inner diameter of the inner needle tube of the coaxial needle is 0.3mm to 0.5mm, and the inner diameter of the outer needle tube is 0.9mm to 1.5mm; Step 2) The electrospinning process parameters include: spinning voltage of 15kV to 22kV, feed rate ratio of liquid core material to shell solution of 0.2 to 0.5:1, vertical distance between the coaxial needle and the receiver of 10cm to 30cm, moving speed of the coaxial needle of 1mm / s to 10mm / s, and spinning time of 3h to 4h.

7. The ceramic fiber-aluminum silicon oxide composite aerogel according to claim 4, characterized in that: Step 3) The organic solvent is at least one of cyclohexane, n-hexane, octane, and acetone; Step 3) The calcination includes the following operations: controlling the heating rate to rise from room temperature to 700℃ to 1200℃ at a rate of 1℃ / min to 5℃ / min, and holding at that temperature for 1h to 4h.

8. A method for preparing ceramic fiber-aluminum silicon oxide composite aerogel as described in any one of claims 1 to 7, characterized in that, Includes the following steps: a) Disperse aluminum chloride hexahydrate, silicon source and boric acid in water to obtain aluminum silicate sol; b) Immerse the zirconia-silica hollow fiber membrane in aluminosilicate sol, stack the zirconia-silica hollow fiber membranes layer by layer, and then freeze-dry and calcinate to obtain ceramic fiber-aluminosilicate oxide composite aerogel.

9. The method for preparing ceramic fiber-aluminum silicon oxide composite aerogel according to claim 8, characterized in that: In step a), the mass ratio of aluminum chloride hexahydrate, silicon source, boric acid, and water is 1:2-3:0.1-0.2:30-40; the silicon source in step a) is at least one of tetraethyl orthosilicate, methyltrimethoxysilane, dimethyldimethoxysilane, and 3-aminopropyltriethoxysilane; in step b), the freeze-drying is carried out under conditions of a cold trap temperature of -50℃ to -70℃ and a vacuum degree of 1Pa to 5Pa, and the drying time is 24h to 72h; in step b), the calcination includes the following operation: controlling the heating rate to rise from room temperature to 700℃ to 1200℃ at a rate of 1℃ / min to 5℃ / min, and holding at that temperature for 1h to 4h.

10. The application of a ceramic fiber-aluminum silicon oxide composite aerogel as described in any one of claims 1 to 7 in the preparation of thermal insulation materials, flame retardant materials, or sound-absorbing and noise-reducing materials.

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