Fiber-reinforced silicon zirconium oxide composite aerogel thermal insulation material and preparation method thereof

Abstract

The invention provides a fiber-reinforced silicon zirconium oxide composite aerogel thermal insulation material and a preparation method thereof, and belongs to the technical field of thermal insulation materials. The invention relates to a fiber-reinforced silicon zirconium oxide composite aerogel thermal insulation material and a preparation method thereof. The preparation method comprises the following steps: providing silicon oxide fibers, and carrying out pretreatment to obtain a silicon oxide fiber preform; the preparation method comprises the following steps: preparing cerium-doped titanium dioxide nanoparticles from tetrabutyl titanate, cerium nitrate, absolute ethyl alcohol and water by adopting a sol-gel method; the preparation method comprises the following steps: adding a silicon source and zirconium oxychloride into an ethanol solution, stirring, adjusting the pH value to 3.0-4.0, adding cerium-doped titanium dioxide nanoparticles, and continuously stirring to form sol; and S3, soaking a silicon oxide fiber preform into the sol prepared in the step S3, pressurizing to fill the silicon oxide fiber preform with the sol, and after gelation, performing aging treatment, freeze drying and heat treatment to finally obtain the product. On the basis of improving the thermal insulation performance of the product, the mechanical property of the product is improved, and the phenomena of shrinkage, collapse and the like generated in the use process of the product are reduced.

Description

Technical Field

[0001] This invention belongs to the field of thermal insulation materials technology, specifically relating to a fiber-reinforced silicon zirconium oxide composite aerogel thermal insulation material and its preparation method. Background Technology

[0002] Industrial kilns generate a large amount of heat during production, and how to effectively insulate them to reduce heat loss and improve energy efficiency is a key issue. The conventional approach is to install insulation materials on the outside of the industrial kiln. However, traditional materials such as ceramic fiber blankets and lightweight castables have problems such as limited insulation capacity, large overall weight, and susceptibility to cracking, which limits their further application.

[0003] Aerogels, as a novel nanoporous material, have attracted widespread attention in the field of thermal insulation due to their extremely low thermal conductivity and high porosity. However, despite their excellent thermal insulation properties, their high brittleness limits their practical applications.

[0004] In the prior art, patent application CN101565296A discloses a method for preparing hydrophobic SiO2-TiO2-ZrO2 dry gel. Using tetraethyl orthosilicate, tetrabutyl titanate, and zirconium oxychloride as raw materials, SiO2-TiO2-ZrO2 gel is prepared via a sol-gel method. After drying at ambient pressure and 50°C, the hydrophobic SiO2-TiO2-ZrO2 dry gel is obtained. This dry gel can be used for thermal insulation, and the porosity of the prepared dry gel can reach 85%, with a specific surface area of ​​190~210 m². 2 / g, pore size 6~30nm, particle diameter less than 20nm, density approximately 0.5g / cm³ 3 Its thermal conductivity can reach 0.0857 W / (m·K), and the wetting angle of water in air is greater than 120°.

[0005] For example, patent application CN120059548A discloses an aerogel thermal insulation coating and its preparation method, including the following steps: mixing a silicon source, ethanol, water, and an acidic catalyst to obtain an aerogel precursor sol; impregnating ceramic fibers in a silane coupling agent ethanol solution and then ultrasonically treating them to obtain hydrophobic modified fibers; mixing the aerogel precursor sol, hydrophobic modified fibers, binder, and nano-titanium dioxide and then ultrasonically dispersing them to obtain a composite sol; using a segmented spraying process, first spraying a high-density sol layer onto the component, and then spraying low-density sol layers layer by layer; subjecting the coated component to supercritical drying treatment to form an aerogel structure; and spraying a fluorinated silane solution onto the coating surface for curing treatment to obtain the aerogel thermal insulation coating. This invention solves the problem of the contradiction between easy cracking and thermal insulation efficiency in traditional homogeneous coatings by improving adhesion and mechanical strength through a high-density inner layer and optimizing thermal insulation performance through a low-density outer layer.

[0006] It is evident that, while fully leveraging the excellent thermal insulation properties of aerogel, improving its mechanical properties to meet the practical application requirements of outer thermal insulation films for industrial kilns has become a research direction with significant practical value. Summary of the Invention

[0007] In view of this, the technical problem to be solved by the present invention is to provide a fiber-reinforced silicon zirconium oxide composite aerogel thermal insulation material and its preparation method, which improves the thermal insulation performance of the product, enhances its mechanical properties, and reduces shrinkage and collapse during the use of the product.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a fiber-reinforced silicon-zirconium oxide composite aerogel thermal insulation material and its preparation method, comprising the following steps: S1: Provide silica fibers, which are pretreated to obtain silica fiber preforms; S2: Tetrabutyl titanate, cerium nitrate, anhydrous ethanol and water are provided, and cerium-doped titanium dioxide nanoparticles are prepared by sol-gel method. S3: Add the silicon source and zirconium oxychloride to the ethanol solution, stir and adjust the pH to 3.0~4.0, add the cerium-doped titanium dioxide nanoparticles, and continue stirring to form a sol; S4: Immerse the silica fiber preform in the sol prepared in step S3, apply pressure to fill the silica fiber preform with the sol, and after gelation, perform an aging treatment, followed by freeze-drying and heat treatment to finally obtain the product. Optionally, in step S1, the pretreatment includes: processing the silica fibers to a length of less than 5 mm, washing them alternately with water and anhydrous ethanol for 15-20 min, and drying them; adding anhydrous ethanol and stirring until homogeneous; then adding a silane coupling agent, ultrasonically mixing, and vacuum filtering to obtain the silica fiber preform.

[0009] Optionally, in step S1, the volume ratio of anhydrous ethanol to the mass ratio of silicon dioxide fiber is (80~120) ml: 10 g; The silane coupling agent is KH550, KH560 or KH570, and the mass ratio of the silane coupling agent to the silica fiber is (0.3~1.0):10.

[0010] Optionally, the frequency of the ultrasound is 30~50kHz and the duration is 20~40min; The temperature of the vacuum filtration is 55~65℃.

[0011] Optionally, in step S2, the sol-gel method includes: adding tetrabutyl titanate dropwise to anhydrous ethanol while continuously stirring during the dropwise addition; after the dropwise addition is complete, adding cerium nitrate solution, stirring, and allowing it to stand to obtain a wet gel; drying and calcining the wet gel to obtain cerium-doped titanium dioxide nanoparticles.

[0012] The cerium-doped titanium dioxide nanoparticles have a particle size of 100~150nm.

[0013] Optionally, in step S2, tetrabutyl titanate can be replaced with tetraethyl titanate or titanium isopropoxide, wherein the volume ratio of tetrabutyl titanate, anhydrous ethanol and water is 20:(25~35):(15~25). The cerium nitrate solution is a mixed solution of cerium nitrate and water, and the mass ratio of cerium nitrate to tetrabutyl titanate is (0.8~1.2) g: 20 ml.

[0014] Optionally, in step S2, the dropping rate of the tetrabutyl titanate is 1 mL / min, the stirring speed is 400 rpm, and the stirring time is 25~35 min; The cerium nitrate solution was added at a rate of 0.5 mL / min, and stirred for 2 hours after addition, then allowed to stand at room temperature for at least 12 hours.

[0015] Optionally, in step S2, the drying temperature is 75~85℃ and the time is 5~7h; The calcination temperature is 450~550℃, the holding time is 2~3h, and the heating rate is 5℃ / min.

[0016] Optionally, in step S3, the silicon source is tetraethyl orthosilicate, propyl orthosilicate, or butyl orthosilicate, the volume concentration of the ethanol solution is 75-85%, the amount of silicon source added is 25-35 ml per 100 ml of ethanol solution, the amount of zirconium oxychloride added is 8-9 g, and the mixture is stirred for 30-40 min.

[0017] Optionally, in step S3, the mass ratio of the cerium-doped titanium dioxide nanoparticles to zirconium oxychloride is 1:(1.0~1.1), and the stirring speed is continued at 400 rpm for 2~3 hours.

[0018] Optionally, in step S4, the mass ratio of the silica fiber preform to the volume ratio of the sol is (10~15) g: 150 ml.

[0019] Optionally, in step S4, the pressurization pressure is 0.2~0.4MPa, the duration is 20~40min, and the tank is shaken once every 10min during the process.

[0020] Optionally, in step S4, the freeze drying includes: pre-freezing at -60℃ for 3~5 hours, and drying at -50℃ in a vacuum environment for 36~50 hours; The heat treatment includes: heating to 550~650℃ in an inert gas atmosphere, holding at that temperature for 2.5~3.5h, and heating at a rate of 2℃ / min.

[0021] A fiber-reinforced silicon-zirconium oxide composite aerogel thermal insulation material is obtained using any of the above preparation methods.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: Based on the above technical solution, this invention provides a fiber-reinforced silicon zirconium oxide composite aerogel thermal insulation material and its preparation method. While improving the thermal insulation performance of the product, it also enhances its mechanical properties and reduces phenomena such as shrinkage and collapse that occur during the use of the product.

[0023] This invention relates to a fiber-reinforced silicon-zirconium oxide composite aerogel insulation material. Using silicon oxide fibers as a framework, it incorporates cerium-doped titanium dioxide nanoparticles and silicon-zirconium sol to create a multiphase composite structure. First, the silicon oxide fiber preform prepared in step S1 serves as the reinforcing framework, tightly integrated with the sol-filling and gelation process in step S4. The silicon oxide fiber framework provides mechanical support and disperses stress. Under pressure, the sol fills to form a continuous matrix. This fiber-matrix composite structure significantly improves compressive strength and thermal shock resistance. Simultaneously, the silicon oxide fiber framework stabilizes the porous structure of the aerogel, preventing collapse during drying and heat treatment, thus ensuring insulation performance. Second, the cerium-doped titanium dioxide nanoparticles synthesized in step S2 are uniformly dispersed into the silicon-zirconium sol in step S3. These cerium-doped titanium dioxide nanoparticles not only act as a reinforcing phase but also as a structurally stabilizing phase, forming a nanocomposite structure with the silicon-zirconium matrix. Cerium doping suppresses the phase transformation of titanium dioxide at high temperatures, synergistically reducing overall material thermal shrinkage and increasing long-term service temperature in conjunction with the high-temperature stability of the silicon-zirconium oxide. Furthermore, the sol (containing silicon zirconium and cerium-doped titanium dioxide nanoparticles) prepared in step S3 is pressurized and filled into a silica fiber preform in step S4 to form a uniform gel network. This ensures that the sol fully penetrates into the fiber gaps, and after gelation, a nanoporous matrix is ​​formed that is tightly bonded to the fibers. This results in a composite material with a hierarchical pore structure after freeze-drying and heat treatment, synergistically reducing thermal conductivity. Simultaneously, the silica fibers and cerium-doped titanium dioxide nanoparticles enhance mechanical strength, making the material less prone to cracking under thermal shock conditions. The entire method, through the organic combination of fiber reinforcement, nanoparticle doping, sol-gel process, and freeze-drying, prepares a multi-scale composite thermal insulation material. Silica fibers provide macroscopic strength, the silicon zirconium aerogel matrix provides nanoporous thermal insulation, and the cerium-doped titanium dioxide nanoparticles further optimize thermal stability and insulation performance. Their synergistic effect enables the material to simultaneously possess low thermal conductivity, low thermal shrinkage, high thermal shock resistance, and high compressive strength, thus meeting the requirements for high-temperature thermal insulation.

[0024] The thermal insulation material prepared by the method of this invention has a compressive strength of 0.3-0.5 MPa at 5%-10% deformation, which is 2-3 times that of conventional aerogels, and it is not easy to collapse; the long-term service temperature is 1200-1400℃, which can well adapt to the normal working temperature of industrial kilns; after cold and hot cycle testing, the volume shrinkage rate of the thermal insulation material is only 3%-5%, which is less than that of conventional silica aerogels and is not easy to crack.

[0025] In summary, the preparation method of the present invention effectively solves the technical problems of improving thermal insulation performance, reducing thermal shrinkage, enhancing thermal shock resistance and improving compressive strength through the cooperation of each step, and the resulting thermal insulation material exhibits superior comprehensive performance. Detailed Implementation

[0026] To better understand the present invention, the following embodiments further illustrate the content of the invention, but the scope of protection of the present invention is not limited to the following embodiments. Numerous specific details are set forth in the following description to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the present invention can be practiced without one or more of these details.

[0027] Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention.

[0028] Unless otherwise specified, all raw materials are derived from commercially available products and do not contain any unspecified components other than unavoidable impurities.

[0029] Example 1: A method for preparing a fiber-reinforced silicon-zirconium oxide composite aerogel thermal insulation material, comprising the following steps: S1: Provide 10g of silica fiber, process the silica fiber to a length of 5mm, wash it alternately with water and anhydrous ethanol for 18min, and dry it; add 100ml of anhydrous ethanol and stir until uniform; then add 0.6g of silane coupling agent KH550, mix it ultrasonically at a frequency of 40kHz for 30min, and vacuum filter it at 60℃ to obtain the silica fiber preform. S2: Provide 20 ml of tetrabutyl titanate, 1.0 g of cerium nitrate, 30 ml of anhydrous ethanol, and 20 ml of water. Add tetrabutyl titanate dropwise to anhydrous ethanol at a rate of 1 mL / min, stirring continuously at 400 rpm for 30 min. After the addition is complete, add cerium nitrate solution at a rate of 0.5 mL / min. Stir for 2 h after the addition is complete, and let stand at room temperature for 12 h to obtain a wet gel. Dry the wet gel at 80 °C for 6 h, and then calcine it at 500 °C for 2.5 h at a heating rate of 5 °C / min to obtain cerium-doped titanium dioxide nanoparticles with a particle size of 120 nm. S3: Add 30 ml of tetraethyl orthosilicate and 8.5 g of zirconium oxychloride to 100 ml of 80% ethanol solution, stir for 35 min, adjust the pH to 3.5 with nitric acid, add 8.3 g of cerium-doped titanium dioxide nanoparticles, continue stirring at 400 rpm for 2.5 h to form a sol. S4: Immerse 12g of silica fiber preform into 150ml of sol. Pressurize the sol with nitrogen at a pressure of 0.3MPa for 30min, shaking the container once every 10min during the process. After gelation, age at 50℃ for 24h, then pre-freeze at -60℃ for 4h, dry at -50℃ in a vacuum environment for 48h, and then heat to 600℃ in an inert gas atmosphere and hold for 3h at a heating rate of 2℃ / min to obtain the product.

[0030] Example 2: A method for preparing a fiber-reinforced silicon-zirconium oxide composite aerogel thermal insulation material, comprising the following steps: S1: Provide 10g of silica fiber, process the silica fiber to a length of 5mm, wash it alternately with water and anhydrous ethanol for 15min, and dry it; add 80ml of anhydrous ethanol and stir until uniform; then add 0.3g of silane coupling agent KH550, mix it ultrasonically at a frequency of 50kHz for 20min, and vacuum filter it at 65℃ to obtain the silica fiber preform. S2: Provide 20 ml of tetraethyl titanate, 0.8 g of cerium nitrate, 25 ml of anhydrous ethanol, and 15 ml of water. Add tetraethyl titanate dropwise to anhydrous ethanol at a rate of 1 mL / min, stirring continuously at 400 rpm for 25 min. After the addition is complete, add cerium nitrate solution at a rate of 0.5 mL / min, stirring for 2 h. Let stand at room temperature for 14 h to obtain a wet gel. Dry the wet gel at 75 °C for 7 h, then calcine at 450 °C for 3 h at a heating rate of 5 °C / min to obtain cerium-doped titanium dioxide nanoparticles with a particle size of 150 nm. S3: Add 25 ml of tetraethyl orthosilicate and 8 g of zirconium oxychloride to 100 ml of 75% ethanol solution, stir for 30 min, adjust the pH to 3.0, add 7.5 g of cerium-doped titanium dioxide nanoparticles, continue stirring at 400 rpm for 2 h to form a sol. S4: Immerse 10g of silica fiber preform in 150ml of sol. Pressurize the silica fiber preform with nitrogen at a pressure of 0.2MPa for 40min, shaking the container once every 10min. After gelation, age at 50℃ for 24h, then pre-freeze at -60℃ for 3h, dry at -50℃ in a vacuum environment for 36h, and then heat to 550℃ in an inert gas atmosphere and hold for 3.5h at a heating rate of 2℃ / min to obtain the product.

[0031] Example 3: A method for preparing a fiber-reinforced silicon-zirconium oxide composite aerogel thermal insulation material, comprising the following steps: S1: Provide 10g of silica fiber, process the silica fiber to a length of 5mm, wash it alternately with water and anhydrous ethanol for 20min, and dry it; add 120ml of anhydrous ethanol and stir until uniform; then add 1.0g of silane coupling agent KH550, mix ultrasonically at a frequency of 50kHz for 20min, and vacuum filter at 55℃ to obtain silica fiber preform. S2: Provide 20 ml of titanium isopropoxide, 1.2 g of cerium nitrate, 35 ml of anhydrous ethanol, and 25 ml of water. Add titanium isopropoxide dropwise to anhydrous ethanol at a rate of 1 mL / min, stirring continuously at 400 rpm for 35 min. After the addition is complete, add cerium nitrate solution at a rate of 0.5 mL / min. Stir for 2 h after the addition is complete, and let stand at room temperature for 12 h to obtain a wet gel. Dry the wet gel at 85 °C for 5 h, and then calcine it at 550 °C for 2 h at a heating rate of 5 °C / min to obtain cerium-doped titanium dioxide nanoparticles with a particle size of 100 nm. S3: Add 35 ml of tetraethyl orthosilicate and 9 g of zirconium oxychloride to 100 ml of 85% ethanol solution, stir for 40 min, adjust the pH to 4.0, add 8.5 g of cerium-doped titanium dioxide nanoparticles, continue stirring at 400 rpm for 2 h to form a sol. S4: Immerse 15g of silica fiber preform into 150ml of sol. Pressurize the sol with nitrogen at a pressure of 0.4MPa for 20min, shaking the container once every 10min until gelation occurs. Then age at 50℃ for 24h, followed by pre-freezing at -60℃ for 5h, drying at -50℃ in a vacuum environment for 50h, and then heating to 650℃ in an inert gas atmosphere and holding for 2.5h at a heating rate of 2℃ / min to obtain the product.

[0032] Example 4: A method for preparing a fiber-reinforced silicon zirconium oxide composite aerogel thermal insulation material, which differs from Example 1 in that the silane coupling agent is KH560.

[0033] Example 5: A method for preparing a fiber-reinforced silicon zirconium oxide composite aerogel thermal insulation material, which differs from Example 1 in that the silane coupling agent is KH570.

[0034] Example 6: A method for preparing a fiber-reinforced silicon zirconium oxide composite aerogel thermal insulation material, which differs from Example 1 in that the silicon source is propyl orthosilicate.

[0035] Example 7: A method for preparing a fiber-reinforced silicon-zirconium oxide composite aerogel thermal insulation material, which differs from Example 1 in that the silicon source is tetrabutyl orthosilicate.

[0036] Comparative Example 1: A method for preparing an aerogel composite thermal insulation material, which differs from Example 1 in that: in step S2, cerium nitrate is not added to obtain titanium dioxide nanoparticles, and in step S3, the titanium dioxide nanoparticles are added, while the remaining steps are the same as in Example 1.

[0037] Comparative Example 2: A method for preparing an aerogel composite thermal insulation material, differing from Example 1 in that step S1 is omitted; steps S2 and S3 are retained, and step S4 is replaced by: pouring the sol into a mold, sealing it, and allowing it to gel at room temperature (25°C). After gelation, the material is freeze-dried and heat-treated to obtain the aerogel composite thermal insulation material. The freeze-drying and heat treatment are the same as in Example 1.

[0038] Comparative Example 3: A method for preparing an aerogel composite thermal insulation material, which differs from Example 1 in that step S2 is omitted, and correspondingly, cerium-doped titanium dioxide nanoparticles are not added in step S3.

[0039] Comparative Example 4: A method for preparing an aerogel composite thermal insulation material, which differs from Example 1 in that: in step S4, "filling the silica fiber preform with sol by nitrogen pressurization" is replaced with atmospheric pressure impregnation.

[0040] Comparative Example 5: A method for preparing an aerogel composite thermal insulation material, which differs from Example 1 in that: in step S4, "freeze-drying" is replaced by drying in a 50°C oven for 12 hours.

[0041] Next, the content of the evaluation test will be explained.

[0042] The thermal insulation materials prepared in Examples 1-3 and Comparative Examples 1-5 were used as samples for the following performance tests.

[0043] 1. Thermal conductivity: The thermal conductivity is tested at an average temperature of 500℃ according to the provisions of GB / T10294 Determination of steady-state thermal resistance and related properties of insulation materials - protective hot plate method.

[0044] 2. Permanent linear change after heating: According to Chapter 7 of GB / T17911-2018, the test temperature is 1300℃, the heating method is slow heating, and the holding time is 24 h. The change rate of the sample length before and after heating is used as the permanent linear change of the sample. The length measuring instrument method and the length measurement method are calculated according to formula (2) in the standard. The average value of the changes in the line at the 4 measurement positions is used as the permanent linear change of the sample after heating.

[0045] 3. Thermal shock resistance: The sample was kept at 1300℃ for 15 minutes, then quickly removed and immersed in room temperature (25℃) water for 5 minutes. This process was repeated until the sample cracked, and the number of cycles was recorded.

[0046] 4. Compressive Strength: Tested according to the method specified in standard GB / T 13480-2014 "Determination of Compressive Properties of Thermal Insulation Products for Buildings". The specimen dimensions are: 200mm (length) × 200mm (width) × 10mm (thickness). Place the specimen in the center of the two pressure plates of the compression testing machine, preload a pressure of (250±10) Pa, set the loading speed to 1mm / min, and load uniformly until the specimen exhibits 10% deformation. Record the maximum load (N) and calculate the compressive strength: Compressive strength (kPa) = 10 3 × Maximum load (N) / Specimen stress area (mm²) 2 ).

[0047] The test results are shown in Table 1.

[0048] Table 1 Performance Test Results The above results show that the thermal conductivity of the insulation material of the present invention is less than 0.05 W / (m·K), which meets the thermal conductivity requirements of GB / T34336 for Type IV products; the permanent linear change after heating is not less than -5.0%, which meets the permanent linear change requirements of GB / T34336 for Type IV products; it has excellent thermal shock resistance; and its compressive strength is greater than 400 kPa, which meets the compressive strength requirements of GB / T34336 when the deformation is 10%.

[0049] Comparative Example 1: Without adding cerium nitrate, using undoped titanium dioxide nanoparticles, the material is more prone to sintering and grain coarsening during high-temperature heat treatment and testing, resulting in increased thermal conductivity. It also exhibits severe and uneven shrinkage at high temperatures and decreased thermal shock resistance, indicating that cerium doping can inhibit high-temperature sintering and shrinkage, improving the material's performance in high-temperature environments. Comparative Example 2: Without using silica fibers, the resulting product is a pure aerogel matrix. Although its thermal conductivity is very low, it is brittle, cannot maintain its shape at high temperatures, and has low mechanical properties, making it difficult to meet application requirements. Comparative Example 3: Without adding cerium-doped titanium dioxide nanoparticles, the scattering effect of the nanoparticles on thermal radiation disappears, and the pinning effect also disappears. Therefore, the product's thermal conductivity increases, and the matrix shrinkage increases at high temperatures. Comparative Example 4: Using atmospheric pressure impregnation, the filling is insufficient, leading to more local defects and uneven distribution of shrinkage stress. The product exhibits decreased thermal conductivity and increased thermal shrinkage. Comparative Example 5: Using low-temperature drying instead of freeze drying resulted in the collapse of the gel network, damage to the nanoporous structure, insufficient support, severe deterioration of the product's thermal conductivity, and a significant decrease in compressive strength.

[0050] As can be seen, the present invention obtains a thermal insulation material with low thermal conductivity, good thermal shock resistance, high temperature stability and compressive strength that can meet the requirements of high temperature working environment by synergistically combining the processes of silica fiber preform, cerium-doped silica nanoparticles, silicon-zirconium composite sol, pressure impregnation and freeze drying.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention, as long as they do not depart from the spirit and scope of the technical solutions of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing a fiber-reinforced silicon-zirconium oxide composite aerogel thermal insulation material, characterized in that: Includes the following steps: S1: Provide silica fibers, which are pretreated to obtain silica fiber preforms; S2: Cerium-doped titanium dioxide nanoparticles were prepared by using tetrabutyl titanate, cerium nitrate, anhydrous ethanol and water via a sol-gel method. S3: Add the silicon source and zirconium oxychloride to the ethanol solution, stir and adjust the pH to 3.0~4.0, add the cerium-doped titanium dioxide nanoparticles, and continue stirring to form a sol; S4: Immerse the silica fiber preform in the sol prepared in step S3, apply pressure to make the sol fill the silica fiber preform, and after gelation, perform an aging treatment, followed by freeze drying and heat treatment to finally obtain the product.

2. The preparation method of the fiber-reinforced silicon-zirconium oxide composite aerogel thermal insulation material as described in claim 1, characterized in that: In step S1, the pretreatment includes: processing the silica fiber to a length of less than 5 mm, washing it alternately with water and anhydrous ethanol for 15-20 min, and drying it; adding anhydrous ethanol and stirring until uniform; then adding a silane coupling agent, ultrasonically mixing, and vacuum filtering to obtain a silica fiber preform.

3. The preparation method of the fiber-reinforced silicon-zirconium oxide composite aerogel thermal insulation material as described in claim 2, characterized in that: In step S1, the volume ratio of anhydrous ethanol to the mass ratio of silicon dioxide fiber is (80~120) ml: 10 g; The silane coupling agent is KH550, KH560 or KH570, and the mass ratio of the silane coupling agent to the silica fiber is (0.3~1.0):

10.

4. The preparation method of the fiber-reinforced silicon-zirconium oxide composite aerogel thermal insulation material as described in claim 3, characterized in that: The frequency of the ultrasound is 30~50kHz, and the duration is 20~40min; The temperature of the vacuum filtration is 55~65℃.

5. The preparation method of the fiber-reinforced silicon-zirconium oxide composite aerogel thermal insulation material as described in claim 4, characterized in that: In step S2, the sol-gel method includes: adding tetrabutyl titanate dropwise to anhydrous ethanol while continuously stirring during the dropwise addition; after the dropwise addition is complete, adding cerium nitrate solution, stirring, and allowing it to stand to obtain a wet gel; drying and calcining the wet gel to obtain cerium-doped titanium dioxide nanoparticles.

6. The method for preparing a fiber-reinforced silicon-zirconium oxide composite aerogel thermal insulation material as described in claim 5, characterized in that: In step S2, the tetrabutyl titanate can be replaced with tetraethyl titanate or titanium isopropoxide, and the volume ratio of the tetrabutyl titanate, anhydrous ethanol and water is 20:(25~35):(15~25). The cerium nitrate solution is a mixture of cerium nitrate and water, and the mass ratio of cerium nitrate to tetrabutyl titanate is (0.8~1.2) g: 20 ml. The drying temperature is 75~85℃, and the time is 5~7 hours; The calcination temperature is 450~550℃, the holding time is 2~3h, and the heating rate is 5℃ / min.

7. The method for preparing a fiber-reinforced silicon-zirconium oxide composite aerogel thermal insulation material as described in claim 6, characterized in that: In step S3, the silicon source is tetraethyl orthosilicate, propyl orthosilicate or butyl orthosilicate, the volume concentration of the ethanol solution is 75-85%, the amount of silicon source added is 25-35 ml per 100 ml of ethanol solution, the amount of zirconium oxychloride added is 8-9 g, and the mixture is stirred for 30-40 min. The mass ratio of cerium-doped titanium dioxide nanoparticles to zirconium oxychloride is 1:(1.0~1.1), and the stirring speed is continued at 400 rpm for 2~3 hours.

8. The method for preparing a fiber-reinforced silicon-zirconium oxide composite aerogel thermal insulation material as described in claim 7, characterized in that: In step S4, the mass ratio of the silica fiber preform to the volume ratio of the sol is (10~15) g: 150 ml; The pressurization pressure is 0.2~0.4MPa, the duration is 20~40min, and the tank is shaken once every 10min during the process.

9. The method for preparing a fiber-reinforced silicon-zirconium oxide composite aerogel thermal insulation material as described in claim 8, characterized in that: In step S4, the freeze drying includes: pre-freezing at -60℃ for 3~5 hours, and drying at -50℃ in a vacuum environment for 36~50 hours; The heat treatment includes: heating to 550~650℃ in an inert gas atmosphere, holding at that temperature for 2.5~3.5h, and heating at a rate of 2℃ / min.

10. A fiber-reinforced silicon-zirconium oxide composite aerogel thermal insulation material obtained by the preparation method of a fiber-reinforced silicon-zirconium oxide composite aerogel thermal insulation material according to any one of claims 1-9.

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