A ceramic-based aerogel and method of making

Abstract

The application provides a ceramic-based aerogel and a preparation method, and belongs to the technical field of aerogel materials. The ceramic-based aerogel takes hollow structure, alumina flexible fiber with good flexibility and porous powder as main raw materials, and can generate fiber gel in situ under the action of a catalyst, so that the flexibility of the ceramic-based aerogel is improved, the thermal conductivity is greatly reduced, the ceramic-based aerogel has good heat absorption effect and excellent fireproof and heat insulation performance, and has good heat insulation effect in low-temperature and high-temperature fields. The synergistic effect of the alumina flexible fiber and the silicon dioxide aqueous solution can enhance the mechanical strength and flexibility of the ceramic-based aerogel, and improve the mechanical ability. The use of a surface treatment agent can enable the ceramic-based aerogel to have good waterproof ability. The synergistic effect of the alumina flexible fiber with low thermal conductivity and the light shielding solvent can enable the ceramic-based aerogel to have better heat absorption effect and excellent fireproof and heat insulation performance. The preparation method has simple process and low cost, and is suitable for large-scale production.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aerogel materials, and relates to a ceramic-based aerogel and a preparation method. BACKGROUND

[0002] With the development of new energy vehicles, the safety of the battery has become the focus of attention, and how to prolong the escape time after the battery fails has become the top priority. Aerogel has the characteristics of high specific surface area and porosity, small density, low thermal conductivity, and good thermal insulation performance, and has been used by most vehicle manufacturers in recent years. Meanwhile, it has become a research hotspot in industrial building insulation, aerospace, nuclear power and various high-temperature engineering systems.

[0003] Aerogel is a three-dimensional network structure porous material composed of nanoskeleton and nanopore, which is mainly divided into glass fiber aerogel and ceramic aerogel. The glass fiber aerogel is a composite material formed by combining aerogel with glass fiber, which has good thermal insulation performance, fireproof performance and waterproof performance. However, the glass fiber aerogel cannot be used in high-temperature fields due to its poor temperature resistance. The ceramic aerogel is a nanoscale porous solid material prepared by sol-gel method, which has low density and thermal conductivity, good thermal insulation performance, good hydrophobicity and air permeability. However, the ceramic aerogel has high thermal conductivity, poor thermal insulation performance, poor rigidity and high brittleness in low-temperature fields, so it is mainly used in high-temperature fields.

[0004] Therefore, there is a need for an aerogel that can be used in both low-temperature and high-temperature fields to expand the application range of aerogel. SUMMARY

[0005] The purpose of the present application is to provide a ceramic-based aerogel and a preparation method to solve the problem of limited application range of existing aerogel.

[0006] To achieve the above purpose, the following technical solutions are adopted in the present application:

[0007] The present application provides a ceramic-based aerogel, and the preparation raw materials include: alumina flexible fiber, porous powder, sol, crosslinking agent, catalyst, silica aqueous solution, surface treatment agent, shading solvent and water.

[0008] The alumina flexible fiber is a pure phase alumina fiber with a hollow structure, with a diameter of 100nm-10um, and has the characteristics of ultra-light, good flexibility, thermal insulation and the like, which can improve the flexibility of the ceramic-based aerogel.

[0009] The preparation method of the alumina flexible fiber is referred to the invention patent CN202211005924.1, which is specifically as follows:

[0010] S01: Dissolve the water-soluble polymer in water to form a co-spinning agent solution; wherein the water-soluble polymer is one or more of polyethylene oxide (PEO), polyvinylpyrrolidone (PVP), and polyvinyl alcohol (PVA);

[0011] S02: Dissolve the water-soluble aluminum salt in deionized water to prepare a salt solution; wherein the water-soluble aluminum salt is one or more of aluminum chloride hexahydrate or aluminum nitrate;

[0012] S03: Slowly add the salt solution to the co-spinning agent solution and mix under magnetic stirring for 0.5 h to 10 d to obtain a spinning precursor; wherein the mass of the water-soluble aluminum salt is 1 to 50 times the mass of the water-soluble polymer;

[0013] S04: Add the spinning precursor to a syringe and extrude the spinning solution through a coaxial inner needle under the push of a mechanical pump, pass a gas through a coaxial outer needle, and form a drawn fiber under the action of the gas flow;

[0014] S05: Heat the drawn fiber in a muffle furnace at a rate of 1-20 ℃ / min to 180-400 ℃, maintain the temperature for 1-8 h, then heat at a rate of 1-20 ℃ / min to 600-1600 ℃, maintain the temperature for 2-8 h, to obtain an alumina flexible fiber.

[0015] In this application, the porous powder includes one or more of a porous silicate powder, a porous silicon powder, a porous carbon powder, and a porous aluminum powder, and has a particle size of 325-5000 mesh. The use of porous powder can reduce the thermal conductivity of the ceramic aerogel and improve the heat insulation effect.

[0016] The porous silicate powder includes water glass 35-45%, solid silica gel 35-45%, sodium metaaluminate 15-25%, and sodium hydroxide 1-5% by mass. The porous silicate powder is prepared using water glass, solid silica gel, and sodium metaaluminate as raw materials and sodium hydroxide as a catalyst. The specific preparation method includes:

[0017] Dissolve the water glass and the solid silica gel in water separately and stir until uniform to form a silica sol; dissolve the sodium metaaluminate in water and stir until uniform to form an aluminum sol; mix the silica sol, the aluminum sol, and the sodium hydroxide uniformly, stir in a constant-temperature water bath at 25-35 ℃ for 30 min, and form a uniform silica-aluminum gel. Age the silica-aluminum gel at 20 ℃ for 20 h, heat at 100 ℃ for 4 h to obtain a crystallization product. After ultrasonic cleaning and centrifugal separation, wash until the pH of the supernatant is less than 9, and dry at 100 ℃ for 4 h to obtain the porous silicate powder.

[0018] The porous silicon powder comprises, by mass percentage, 69.5-79.5% of silica sol, 20-30% of potassium silicate, and 0.5-3% of potassium hydroxide. The porous silicon powder is prepared by using silica sol and potassium silicate as raw materials and potassium hydroxide as a catalyst. The specific preparation method comprises the following steps:

[0019] The silica sol is dissolved in water and stirred to form a silica sol solution. The potassium silicate is dissolved in water and stirred to form a potassium silicate sol. The silica sol solution, the potassium silicate sol, and the potassium hydroxide are uniformly mixed, stirred in a constant-temperature water bath at 25-35°C for 30 min, and a uniform mixed sol is formed. The mixed sol is aged at 60°C for 15 h, heated at 120°C for 2 h to obtain a gel product. The gel product is placed in a microwave synthesis instrument, and a crystallization reaction is performed under the conditions of a microwave radiation power of 100 W, a microwave radiation temperature of 120°C, and a microwave radiation time of 10 min to obtain a crystallization product. After cooling, the crystallization product is taken out, ultrasonically cleaned, centrifugally separated, washed until the pH of the supernatant is less than 9, and dried at 100°C for 4 h to obtain the porous silicon powder.

[0020] The porous carbon powder comprises, by mass percentage, 25-35% of sodium carbonate, 60-70% of sodium metaaluminate, and 2-10% of sodium hydroxide. The porous carbon powder is prepared by using sodium carbonate and sodium metaaluminate as raw materials and sodium hydroxide as a catalyst. The specific preparation method comprises the following steps:

[0021] The sodium carbonate is dissolved in water and stirred to form a sodium carbonate solution. The sodium metaaluminate is dissolved in water and stirred to form an aluminum sol. The sodium carbonate solution, the aluminum sol, and the sodium hydroxide are uniformly mixed, stirred in a constant-temperature water bath at 25-35°C for 30 min, and a uniform mixed sol is formed. The mixed sol is aged at 40°C for 20 h, heated at 90°C for 3 h to obtain a gel product. The gel product is placed in a microwave synthesis instrument, and a crystallization reaction is performed under the conditions of a microwave radiation power of 120 W, a microwave radiation temperature of 100°C, and a microwave radiation time of 15 min to obtain a crystallization product. After cooling, the crystallization product is taken out, ultrasonically cleaned, centrifugally separated, washed until the pH of the supernatant is less than 9, and dried at 100°C for 4 h to obtain the porous carbon powder.

[0022] The porous aluminum powder comprises, by mass percentage, 45-55% of neutral aluminum solution, 15-25% of water glass, 22-32% of sodium metaaluminate, and 1-5% of sodium hydroxide. The porous aluminum powder is prepared by using water glass, neutral aluminum sol, and sodium metaaluminate as raw materials and sodium hydroxide as a catalyst. The specific preparation method comprises the following steps:

[0023] Dissolve the water glass in water, stir until uniform, form a silica sol; dissolve the neutral aluminum sol and sodium metaaluminate in water respectively, stir until uniform, form an aluminum sol; mix the silica sol, aluminum sol and sodium hydroxide uniformly, stir in a constant temperature water bath at 25-35℃ for 30min, form a uniform silica-aluminum gel. After aging the silica-aluminum gel at 60℃ for 16h, heat to crystallize at 130℃ for 1h, obtain a crystallization product. After ultrasonic cleaning, centrifugal separation, washing until the pH of the supernatant is <9, drying at 100℃ for 4h, obtain a porous aluminum-based powder.

[0024] In the present application, the sol comprises one or more of methanol, ethanol and butanol; the crosslinking agent is one or more of tetraethyl orthosilicate and trimethoxysilane; the catalyst is tributylaluminum oxide; the solid content in the aqueous silica solution is 2-20%; the surface treatment agent is WP001 mixed solution produced by Nanjing Qinhai Business and Trade Co., Ltd. with batch number 20250215006; the light shielding solvent comprises one or more of tetrabutyl titanate, isopropyl titanate and titanium dioxide sol.

[0025] In the present application, the preparation raw materials of the ceramic-based aerogel comprise, in terms of weight fraction: 15-40 parts of alumina flexible fiber, 2-20 parts of porous powder, 0.5-5 parts of sol, 0.2-3 parts of crosslinking agent, 0.5-10 parts of catalyst, 400-2000 parts of aqueous silica solution, 5-20 parts of surface treatment agent, 100-1500 parts of light shielding solvent and 1000-3500 parts of water.

[0026] The present application provides a preparation method of a ceramic-based aerogel, which comprises:

[0027] S01: After mixing the alumina flexible fiber, porous powder, sol, crosslinking agent, catalyst and water, synthesize a fiber gel under the conditions of 90-250℃ and 0.1-3MPa by in-situ generation method.

[0028] Mix the alumina flexible fiber, porous powder, sol, crosslinking agent, catalyst and water, and under the specific temperature and pressure of 90-250℃ and 0.1-3MPa, the alumina flexible fiber, porous powder and crosslinking agent undergo a physical and chemical reaction under the action of the catalyst to generate a thermodynamically stable fiber gel. In the present application, the reaction temperature and pressure are specific, and the alumina flexible fiber and porous powder cannot react under other temperatures and pressures.

[0029] S02: After the fiber gel is immersed in the aqueous silica solution, dry at 180-250℃ to form a hard fiber gel.

[0030] The fiber gel is soaked in the silica aqueous solution for 20-30 minutes to make the silica aqueous solution fully immerse in the fiber gel. After the soaking, the fiber gel is placed in a drying oven and dried at 180-250 DEG C to make the silica ceramicize and generate the hard fiber gel with hard material, so as to enhance the structural strength of the ceramic aerogel.

[0031] In the application, the fiber gel soaked in the silica aqueous solution must be dried at 180-250 DEG C. If the temperature is lower than 180 DEG C, the silica will not ceramicize and the surface of the fiber gel will not be hardened. If the temperature is higher than 250 DEG C, the energy consumption is high, which leads to high preparation cost.

[0032] S03: After the hard fiber gel is soaked in the surface treatment agent, the hard fiber gel is dried in a microwave oven at 60-180 DEG C to form the waterproof fiber gel.

[0033] The hard fiber gel is soaked in the surface treatment agent for 10-15 minutes to make the surface treatment agent immerse in the surface of the hard fiber gel. After the soaking, the hard fiber gel is dried in a microwave oven at 60-180 DEG C to evaporate the solvent on the surface of the hard fiber gel, so that the surface treatment agent is solidified on the surface of the hard fiber gel to form the waterproof waterproof fiber gel.

[0034] In the application, the hard fiber gel is dried in the form of microwave heating, which has the advantages of short drying time and high efficiency.

[0035] S04: After the surface of the waterproof fiber gel is uniformly sprayed with the light shielding solvent, the waterproof fiber gel is dried in an infrared oven at 80-120 DEG C to obtain the ceramic aerogel.

[0036] The application has the following beneficial effects:

[0037] (1) The ceramic aerogel takes the hollow structure, the alumina flexible fiber with good flexibility and the porous powder as the main raw materials, and can generate the fiber gel in situ under the action of the catalyst, which improves the flexibility of the ceramic aerogel, greatly reduces the thermal conductivity, makes the ceramic aerogel have good heat absorption effect and excellent fireproof and heat insulation performance, and is equivalent to the glass fiber aerogel in the low temperature field and better than the ceramic aerogel in the high temperature field.

[0038] (2) The synergistic effect of the alumina flexible fiber and the silica aqueous solution can enhance the mechanical strength and flexibility of the ceramic aerogel and improve the mechanical ability.

[0039] (3) The use of the surface treatment agent can make the ceramic aerogel have good waterproof ability, and the synergistic effect of the alumina flexible fiber with low thermal conductivity and the light shielding solvent can make the ceramic aerogel have better heat absorption effect and excellent fireproof and heat insulation performance.

[0040] (4) The preparation method is simple in process and low in cost, and is suitable for large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 A microscope detection graph of the ceramic-based aerogel prepared in the embodiment of the application;

[0042] Figure 2 A comparison graph of the samples after the back temperature experiment of the ceramic-based aerogel, the glass fiber aerogel and the ceramic aerogel prepared in the embodiment 6 of the application;

[0043] Figure 3 A waterproof experiment graph of the ceramic-based aerogel prepared in the embodiment 6 of the application. DETAILED DESCRIPTION

[0044] The technical solutions of the application are further explained and described below through specific embodiments.

[0045] Embodiment 1

[0046] The embodiment of the application provides a ceramic-based aerogel, and raw materials for preparing the ceramic-based aerogel include, in terms of weight fractions, 30 parts of alumina flexible fiber, 4 parts of porous silicate powder, 0.6 parts of methanol, 0.8 parts of tetraethyl orthosilicate, 0.5 parts of tributylaluminum oxide, 1000 parts of aqueous silicon dioxide solution, 8 parts of WP001 mixed solution, 300 parts of tetrabutyl titanate and 3000 parts of water.

[0047] The preparation method of the above ceramic-based aerogel includes:

[0048] S101: The alumina flexible fiber, the porous silicate powder, the methanol, the tetraethyl orthosilicate, the tributylaluminum oxide and the water are mixed, and a fiber gel is synthesized by using an in-situ generation method under the condition of 90℃ and 0.5MPa.

[0049] S102: The fiber gel is soaked in the aqueous silicon dioxide solution for 20min, after the soaking is completed, the fiber gel is placed in a drying oven and dried at 180℃ to form a hard fiber gel.

[0050] S103: The hard fiber gel is soaked in the WP001 mixed solution for 10min, after the soaking is completed, the hard fiber gel is dried in a microwave environment at 80℃ to form a waterproof fiber gel.

[0051] S104: After the tetrabutyl titanate is uniformly sprayed on the surface of the waterproof fiber gel, infrared drying at 120℃ is adopted to obtain the ceramic-based aerogel.

[0052] Embodiment 2

[0053] The embodiment of the present application provides a ceramic-based aerogel, and raw materials for preparing the ceramic-based aerogel include, in terms of weight percentage, 25 parts of alumina flexible fiber, 6 parts of porous silicon powder, 1.5 parts of ethanol, 0.5 parts of trimethoxysilane, 4 parts of tributylaluminum oxide, 500 parts of aqueous silicon dioxide solution, 5 parts of WP001 mixed solution, 1200 parts of isopropyl titanate, and 2500 parts of water.

[0054] The preparation method of the ceramic-based aerogel includes the following steps.

[0055] S201: The alumina flexible fiber, the porous silicon powder, the ethanol, the trimethoxysilane, the tributylaluminum oxide, and the water are mixed, and a fiber gel is synthesized by using an in-situ generation method under the condition of 150 DEG C and 0.8 MPa.

[0056] S202: The fiber gel is soaked in the aqueous silicon dioxide solution for 30 min, and after the soaking is completed, the fiber gel is placed in a drying oven and dried at 180 DEG C to form a hard fiber gel.

[0057] S203: The hard fiber gel is soaked in the WP001 mixed solution for 15 min, and after the soaking is completed, the hard fiber gel is dried in a microwave environment at 180 DEG C to form a waterproof fiber gel.

[0058] S204: After the isopropyl titanate is uniformly sprayed on the surface of the waterproof fiber gel, infrared drying at 110 DEG C is performed to obtain the ceramic-based aerogel.

[0059] Embodiment 3

[0060] The embodiment of the present application provides a ceramic-based aerogel, and raw materials for preparing the ceramic-based aerogel include, in terms of weight percentage, 20 parts of alumina flexible fiber, 15 parts of porous aluminum powder, 0.4 parts of methanol, 0.5 parts of butanol, 1.5 parts of trimethoxysilane, 1 part of tributylaluminum oxide, 2000 parts of aqueous silicon dioxide solution, 10 parts of WP001 mixed solution, 500 parts of titanium dichloride sol, and 2000 parts of water.

[0061] The preparation method of the ceramic-based aerogel includes the following steps.

[0062] S301: The alumina flexible fiber, the porous aluminum powder, the methanol, the butanol, the trimethoxysilane, the tributylaluminum oxide, and the water are mixed, and a fiber gel is synthesized by using an in-situ generation method under the condition of 100 DEG C and 1 MPa.

[0063] S302: The fiber gel is soaked in the aqueous silicon dioxide solution for 25 min, and after the soaking is completed, the fiber gel is placed in a drying oven and dried at 180 DEG C to form a hard fiber gel.

[0064] S303: Soak the rigid fiber gel in the WP001 mixed solution for 12 minutes, and then dry the rigid fiber gel in a microwave environment at 80 DEG C to form a waterproof fiber gel.

[0065] S304: After uniformly spraying the titanium dichloride sol on the surface of the waterproof fiber gel, infrared drying at 80 DEG C is performed to obtain the ceramic-based aerogel.

[0066] Example 4

[0067] The ceramic-based aerogel provided by the embodiment of the application is prepared from the following raw materials in terms of weight fraction: 35 parts of alumina flexible fiber, 4 parts of porous silicate powder, 6 parts of porous silicon powder, 3 parts of butanol, 2 parts of tetraethyl orthosilicate, 2 parts of tributyl aluminum oxide, 800 parts of aqueous silicon dioxide solution, 10 parts of WP001 mixed solution, 700 parts of tetrabutyl titanate, 600 parts of isopropyl titanate, and 3500 parts of water.

[0068] The preparation method of the ceramic-based aerogel includes the following steps:

[0069] S401: Mix the alumina flexible fiber, the porous silicate powder, the porous silicon powder, the butanol, the tetraethyl orthosilicate, the tributyl aluminum oxide, and the water, and then synthesize a fiber gel by using an in-situ generation method under the condition of 250 DEG C and 3 MPa.

[0070] S402: Soak the fiber gel in the aqueous silicon dioxide solution for 25 minutes, and then dry the fiber gel in a drying oven at 180 DEG C to form a rigid fiber gel.

[0071] S403: Soak the rigid fiber gel in the WP001 mixed solution for 10 minutes, and then dry the rigid fiber gel in a microwave environment at 150 DEG C to form a waterproof fiber gel.

[0072] S404: After uniformly spraying the tetrabutyl titanate and the isopropyl titanate on the surface of the waterproof fiber gel, infrared drying at 120 DEG C is performed to obtain the ceramic-based aerogel.

[0073] Example 5

[0074] The ceramic-based aerogel provided by the embodiment of the application is prepared from the following raw materials in terms of weight fraction: 15 parts of alumina flexible fiber, 5 parts of porous silicate powder, 10 parts of porous aluminum powder, 4 parts of ethanol, 0.8 parts of tetraethyl orthosilicate, 0.2 parts of trimethoxysilane, 8 parts of tributyl aluminum oxide, 600 parts of aqueous silicon dioxide solution, 15 parts of WP001 mixed solution, 800 parts of isopropyl titanate, and 1500 parts of water.

[0075] The preparation method of the ceramic-based aerogel includes the following steps:

[0076] S501: mixing alumina flexible fiber, porous silicate powder, porous aluminum powder, ethanol, tetraethyl orthosilicate, trimethoxysilane, tributylaluminum oxide and water, and synthesizing fiber gel under the condition of 150℃ and 1.5MPa by in-situ generation method.

[0077] S502: soaking the fiber gel in the aqueous solution of silicon dioxide for 20 minutes, and then drying the fiber gel in a drying oven at 250℃ to form hard fiber gel.

[0078] S503: soaking the hard fiber gel in the WP001 mixed solution for 10 minutes, and then drying the hard fiber gel in a microwave environment at 100℃ to form waterproof fiber gel.

[0079] S504: spraying isopropyl titanate on the surface of the waterproof fiber gel, and then drying by infrared drying at 100℃ to obtain ceramic-based aerogel.

[0080] Example 6

[0081] The ceramic-based aerogel provided by the embodiment of the application is prepared from the following raw materials by weight fraction: 20 parts of alumina flexible fiber, 3 parts of porous silicate powder, 3 parts of porous aluminum powder, 2 parts of porous carbon powder, 0.4 parts of methanol, 0.5 parts of butanol, 1 part of trimethoxysilane, 3 parts of tributylaluminum oxide, 1500 parts of aqueous solution of silicon dioxide, 10 parts of WP001 mixed solution, 500 parts of isopropyl titanate and 2000 parts of water.

[0082] The preparation method of the above ceramic-based aerogel comprises:

[0083] S601: mixing alumina flexible fiber, porous silicate powder, porous aluminum powder, porous carbon powder, methanol, butanol, trimethoxysilane, tributylaluminum oxide and water, and synthesizing fiber gel under the condition of 200℃ and 2MPa by in-situ generation method.

[0084] S602: soaking the fiber gel in the aqueous solution of silicon dioxide for 30 minutes, and then drying the fiber gel in a drying oven at 180℃ to form hard fiber gel.

[0085] S603: soaking the hard fiber gel in the WP001 mixed solution for 10 minutes, and then drying the hard fiber gel in a microwave environment at 120℃ to form waterproof fiber gel.

[0086] S604: spraying isopropyl titanate on the surface of the waterproof fiber gel, and then drying by infrared drying at 80℃ to obtain ceramic-based aerogel.

[0087] Example 7

[0088] The embodiment of the present application provides a ceramic-based aerogel, and raw materials for preparing the ceramic-based aerogel include, in terms of weight fractions, 10 parts of alumina flexible fiber, 6 parts of porous silicate powder, 8 parts of porous carbon powder, 0.3 parts of methanol, 2 parts of ethanol, 2 parts of tetraethyl orthosilicate, 1 part of trimethoxysilane, 2 parts of tributylaluminum oxide, 1500 parts of aqueous silicon dioxide solution, 20 parts of WP001 mixed solution, 300 parts of tetrabutyl titanate, 300 parts of titanium dioxide sol, and 1000 parts of water.

[0089] The preparation method of the ceramic-based aerogel includes the following steps.

[0090] S701: The alumina flexible fiber, the porous silicate powder, the porous carbon powder, the methanol, the ethanol, the tetraethyl orthosilicate, the trimethoxysilane, the tributylaluminum oxide, and the water are mixed, and a fiber gel is synthesized by using an in-situ generation method under the condition of 170 DEG C and 2.5 MPa.

[0091] S702: The fiber gel is soaked in the aqueous silicon dioxide solution for 25 min, and after the soaking is completed, the fiber gel is placed in a drying oven and dried at 200 DEG C to form a hard fiber gel.

[0092] S703: The hard fiber gel is soaked in the WP001 mixed solution for 13 min, and after the soaking is completed, the hard fiber gel is dried in a microwave environment at 100 DEG C to form a waterproof fiber gel.

[0093] S704: After the waterproof fiber gel is uniformly sprayed with the tetrabutyl titanate and the titanium dioxide sol, infrared drying at 90 DEG C is performed to obtain the ceramic-based aerogel.

[0094] Embodiment 8

[0095] The embodiment of the present application provides a ceramic-based aerogel, and raw materials for preparing the ceramic-based aerogel include, in terms of weight fractions, 25 parts of alumina flexible fiber, 3 parts of porous silicate powder, 3 parts of porous silicon powder, 2 parts of porous carbon powder, 5 parts of ethanol, 1 part of tetraethyl orthosilicate, 3 parts of tributylaluminum oxide, 1300 parts of aqueous silicon dioxide solution, 10 parts of WP001 mixed solution, 1500 parts of isopropyl titanate, and 2500 parts of water.

[0096] The preparation method of the ceramic-based aerogel includes the following steps.

[0097] S801: The alumina flexible fiber, the porous silicate powder, the porous silicon powder, the porous carbon powder, the ethanol, the tetraethyl orthosilicate, the tributylaluminum oxide, and the water are mixed, and a fiber gel is synthesized by using an in-situ generation method under the condition of 140 DEG C and 1.5 MPa.

[0098] S802: The fiber gel is soaked in the aqueous silicon dioxide solution for 20 min, and after the soaking is completed, the fiber gel is placed in a drying oven and dried at 180 DEG C to form a hard fiber gel.

[0099] S803: Soak the hard fiber gel in the WP001 mixed solution for 15 min, and then dry the hard fiber gel in a microwave environment at 120 DEG C to form a waterproof fiber gel.

[0100] S804: After spraying isopropyl titanate on the surface of the waterproof fiber gel, infrared drying at 80 DEG C is performed to obtain a ceramic aerogel.

[0101] The ceramic aerogel prepared in Example 6 of the present application is subjected to microscopic detection, and the attached Figure 1 It can be seen from the attached Figure 1 that the slender structure in the ceramic aerogel prepared in Example 6 of the present application is an aluminum oxide flexible fiber, and the surface of the flexible fiber is loaded with black and white granular porous powders or porous powders with a larger particle size due to agglomeration.

[0102] The commercially available glass fiber aerogel is taken as Comparative Example 1, the commercially available ceramic aerogel is taken as Comparative Example 2, and the ceramic aerogel prepared in Example 6 of the present application is subjected to hardness, thermal conductivity, back temperature and waterproof performance tests, and the specific contents are as follows:

[0103] 1. Hardness detection

[0104] The LX-A Shore hardness tester is used to test the hardness of the aerogels in Example 6, Comparative Example 1 and Comparative Example 2, and the detection results are shown in Table 1.

[0105] Table 1: Hardness detection data of the aerogels in Example 6, Comparative Example 1 and Comparative Example 2

[0106]

[0107] It can be seen from Table 1 that the hardness of the commercially available ceramic aerogel in Comparative Example 2 is poor, while the hardness of the ceramic aerogel in Example 6 of the present application and the commercially available glass fiber aerogel in Comparative Example 1 is high, which is convenient for transportation and construction.

[0108] 2. Thermal conductivity detection

[0109] The thermal conductivity of the aerogels in Example 6, Comparative Example 1 and Comparative Example 2 is detected at 100 DEG C, 300 DEG C, 500 DEG C, 700 DEG C and 900 DEG C, and the detection results are shown in Table 2.

[0110] Table 2: Thermal conductivity detection data of the aerogels in Example 6, Comparative Example 1 and Comparative Example 2

[0111]

[0112] As shown in Table 2, the thermal conductivity of the glass fiber aerogel in Comparative Example 1 is small at low temperature, and when the temperature exceeds 600℃, the temperature limit of the glass fiber aerogel is reached; as the temperature continues to rise, the thermal conductivity increases significantly and the increasing rate is particularly fast. The thermal conductivity of the ceramic aerogel in Comparative Example 2 is large at low temperature, and as the temperature rises, the increasing rate of the thermal conductivity is low, and the thermal conductivity advantage is more and more obvious. The thermal conductivity of the ceramic aerogel in Example 6 is small at low temperature, and is basically the same as that of Comparative Example 1; as the temperature continues to rise, the increasing rate of the thermal conductivity is low, and the thermal conductivity at the same temperature is lower than that of Comparative Example 2. As can be seen, the ceramic aerogel prepared in the application has a low thermal conductivity at low and high temperatures, which is beneficial to the heat preservation and insulation performance of the product.

[0113] 3. Back temperature detection

[0114] The same thickness of the aerogel in Example 6, Comparative Example 1 and Comparative Example 2 was irradiated by a spray gun with a temperature of 1100℃, and the back temperature of each group was detected at 0min, 1min, 3min, 5min, 7min and 9min, respectively. The detection results are shown in Table 3. The comparison chart of the samples after back temperature test is shown in Figure 2

[0115] Table 3: Back temperature detection data of the aerogel in Example 6, Comparative Example 1 and Comparative Example 2

[0116]

[0117] As shown in Table 3, under the irradiation of the spray gun with a temperature of 1100℃, the glass fiber aerogel in Comparative Example 1 is directly burned through in less than 1min. In different time periods, the back temperature of the ceramic aerogel in Example 6 is lower than that of the ceramic aerogel in Comparative Example 2. This is because the glass fiber aerogel in Comparative Example 1 is composed of glass fiber, and when the temperature exceeds 600℃, the glass fiber will melt and be burned through. The ceramic aerogel in Example 6 has a low thermal conductivity, and in the synergistic effect of the high-temperature radiation sunscreen, the back temperature of the ceramic aerogel is lower than that of the ceramic aerogel in Comparative Example 2.

[0118] In addition, from the attached Figure 2 It can be seen that the glass fiber aerogel sample in Comparative Example 1 has been burned through; the ceramic aerogel sample in Comparative Example 2 is bent, which indicates that its structural strength is poor; the ceramic aerogel sample in Example 6 is in good condition.

[0119] 4. Waterproof performance detection

[0120] ​The water was dropped on the aerogel samples in Example 6, Comparative Example 1 and Comparative Example 2 by using a dropper, and the water absorption rate of each group was measured after standing for 24 h. The detection results are shown in Table 4, and the waterproof experiment diagram of the ceramic-based aerogel in Example 6 is shown in FIG. 2. Figure 3

[0121] Table 4: Water absorption rate detection data of the aerogels in Example 6, Comparative Example 1 and Comparative Example 2

[0122]

[0123] It can be seen from Table 4 and FIG. 2 that the aerogels in Example 6, Comparative Example 1 and Comparative Example 2 all have good waterproof performance. Figure 3

[0124] It can be seen from the above detection that, compared with the glass fiber aerogel and the ceramic aerogel, the ceramic-based aerogel prepared in the embodiments of the present application has higher hardness, lower thermal conductivity, lower back temperature and lower water absorption rate. It not only can achieve the purpose of fireproofing and heat insulation, but also has good waterproof performance.

[0125] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.​​

Claims

1. A ceramic-based aerogel, characterized in that, The raw materials for preparation include: flexible alumina fibers, porous powder, sol, crosslinking agent, catalyst, silica aqueous solution, surface treatment agent, light-shielding solvent, and water. The flexible alumina fibers are hollow pure-phase alumina fibers with a diameter of 100 nm to 10 μm. The porous powder includes one or more of porous silicate powder, porous silicon powder, porous carbon powder, and porous aluminum powder. The preparation method of the ceramic-based aerogel includes: Alumina flexible fibers, porous powder, sol, crosslinking agent, catalyst and water are mixed and then synthesized into fiber gel by in-situ generation under conditions of 90-250℃ and 0.1-3MPa. After the fiber gel is soaked in an aqueous silica solution, it is dried at 180-250°C to allow the silica to undergo a ceramicization reaction, forming a hard fiber gel. After the rigid fiber gel is soaked in the surface treatment agent, it is dried by microwave at 60-180℃ to solidify the surface treatment agent on the surface of the rigid fiber gel and form a waterproof fiber gel. After uniformly spraying a light-shielding solvent onto the surface of the waterproof fiber gel, it is dried using infrared technology at 80-120℃ to obtain a ceramic-based aerogel.

2. The ceramic-based aerogel according to claim 1, characterized in that, The raw materials for preparation include, by weight, 15-40 parts of alumina flexible fiber, 2-20 parts of porous powder, 0.5-5 parts of sol, 0.2-3 parts of crosslinking agent, 0.5-10 parts of catalyst, 400-2000 parts of silica aqueous solution, 5-20 parts of surface treatment agent, 100-1500 parts of light-shielding solvent, and 1000-3500 parts of water.

3. The ceramic-based aerogel according to claim 1, characterized in that, The porous silicate powder comprises, by weight percentage, 35-45% water glass, 35-45% solid silica gel, 15-25% sodium aluminate, and 1-5% sodium hydroxide.

4. The ceramic-based aerogel according to claim 1, characterized in that, The porous silicon-based powder comprises, by mass percentage, 69.5-79.5% silica sol, 20-30% potassium silicate, and 0.5-3% potassium hydroxide.

5. The ceramic-based aerogel according to claim 1, characterized in that, The porous carbon-based powder comprises, by mass percentage, 25-35% sodium carbonate, 60-70% sodium aluminate, and 2-10% sodium hydroxide.

6. The ceramic-based aerogel according to claim 1, characterized in that, The porous aluminum-based powder comprises, by mass percentage, 45-55% neutral aluminum solution, 15-25% water glass, 22-32% sodium aluminate, and 1-5% sodium hydroxide.

7. The ceramic-based aerogel according to claim 1, characterized in that, The sol includes one or more of methanol, ethanol and butanol, and the crosslinking agent is one or more of tetraethyl orthosilicate and trimethoxysilane.

8. The ceramic-based aerogel according to claim 1, characterized in that, The catalyst is tributyl alumina, the surface treatment agent is a WP001 mixture, and the light-shielding solvent includes one or more of tetrabutyl titanate, isopropyl titanate, and titanium dioxide sol.

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