Preparation method of fiber composite high-entropy zirconium-based ceramic aerogel material

Abstract

The invention relates to a preparation method of a fiber composite high-entropy zirconium-based ceramic aerogel material, and belongs to the field of porous material preparation processes. The preparation method comprises the following steps: preparing a ceramic aerogel precursor of (Yb < 0.2 > Y < 0.2 > Ce < 0.2 > Lu < 0.2 > Tm < 0.2 >) 2Zr < 2 > O < 7 > composite fibers by using a sol-gel combined fiber impregnation method, standing the gel, aging, and preparing the (Yb < 0.2 > Y < 0.2 > Ce < 0.2 > Lu < 0.2 > Tm < 0.2 >) 2Zr < 2 > O < 7 > high-entropy ceramic composite aerogel with light weight and high thermal stability by using a supercritical drying combined heat treatment process. The blocky (Yb < 0.2 > Y < 0.2 > Ce < 0.2 > Lu < 0.2 > Tm < 0.2 >) 2Zr2O7 high-entropy ceramic aerogel prepared by the preparation method disclosed by the invention can resist the temperature of 1400 DEG C, and has a good application prospect in the fields of aerospace, industrial kilns and chemical engineering.

Description

Technical Field

[0001] The invention belongs to the field of porous material preparation and relates to a method for preparing a fiber-composite high-entropy zirconium-based ceramic aerogel material. Background Art

[0002] The rapid development of the aerospace industry has placed higher demands on the thermal insulation performance of core components in hypersonic vehicle propulsion systems. Supersonic vehicles are subject to extreme aerodynamic thermal environments during high-speed operation, causing their surface temperatures to rise dramatically. Therefore, the research and development of lightweight thermal insulation materials that can withstand high temperatures is crucial to ensuring the safe operation of internal components in hypersonic vehicles.

[0003] Aerogel is a porous material composed of nanostructures with excellent characteristics such as extremely low density, high porosity, and large specific surface area. Complex solid-phase heat transfer channels exist in the material, and the pore size is small relative to the mean free path of air molecules. High-entropy ceramics have a high-entropy effect. The Gibbs free energy in the material system is reduced, which can form a stable phase structure. The solid solution of five or more rare earth elements in the system causes lattice distortion and increases the heat transfer resistance, thereby generating a slow diffusion and increasing the energy barrier for sintering mass transfer. The solid solution of multiple elements can have better performance than a single component. The high-entropy ceramic aerogel structure can significantly improve the thermal insulation performance of the material. The composite electrospun one-dimensional nanofibers in high-entropy aerogel can extend the heat transfer path, improve the thermal insulation performance of the composite material, eliminate the weak point-to-point connection between high-entropy nanoparticles, and solve the brittleness problem of aerogel materials.

[0004] Currently, high-entropy disilicate ceramics are prepared using a solid-phase method. They have a dense structure and a high thermal conductivity of 0.9W / (m·K). During the preparation process, ball milling equipment is required to evenly mix the oxide raw materials (see Ultra-low thermal conductivity and hydrophobic properties of high entropy β-type quaternary pyrosilicate[J]. Journal of the European Ceramic Society 44(2024)1698–1709). This results in high synthesis energy consumption, high sample density, and high thermal conductivity. CN 115141030 A discloses a method for preparing high-entropy zirconate ceramic aerogel using a sol-gel method, but this material has low temperature resistance and low strength. Studies have found that high-entropy zirconate ceramic aerogels are prone to fragmentation at high temperatures (reference High entropy (LaCeSmEuNd) 2Zr2O7 ceramic aerogel with lowthermal conductivity and excellent structural heat resistance. [J]. Journal of the European Ceramic Society 42 (2022) 5964–5972), and a dry pressing process is required to ensure their structural integrity at high temperatures. The ceramic aerogels after dry pressing have high density and high thermal conductivity. Therefore, there is an urgent need to solve the problems of temperature resistance and structural integrity of high-entropy ceramic aerogels. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for preparing a fiber-composite high-entropy zirconium-based ceramic aerogel material, which has a nano-scale porous skeleton structure, low density and high thermal stability.

[0006] The technical solution of the present invention is: a method for preparing a fiber-composite high-entropy zirconium-based ceramic aerogel material, the specific steps of which are as follows:

[0007] (1) Preparation of high entropy sol: According to the chemical formula (Yb 0.2 Ce 0.2 Y 0.2 Tm 0.2 Lu 0.2 )2Zr2O7 molar ratio of rare earth elements ytterbium source, cerium source, yttrium source, thulium source, lutetium source and zirconium source are weighed, anhydrous ethanol or deionized water mixed solvent is added, and stirred until completely dissolved to obtain a hydrolyzed sol;

[0008] (2) Preparation of silica fiber: dissolving a silicon source in a mixed solvent of anhydrous ethanol and deionized water to prepare a silicon solution; dissolving a spinning aid in the solvent to prepare a spinning aid solution; stirring and mixing the silicon solution and the spinning aid solution to obtain a spinning solution with spinnability, obtaining silica precursor fibers under high voltage current in an electrospinning device, and then placing the precursor fibers in a box furnace for heat treatment to obtain silica fibers;

[0009] (3) Preparation of composite aerogel: a coagulant is introduced into the sol obtained in step (1) under temperature control conditions to obtain a high-entropy zirconate sol; the silica fiber obtained in step (2) is then immersed in the high-entropy zirconate sol that has not formed a gel, and the fiber is placed in an oven and allowed to stand to undergo a gelation reaction to obtain a wet gel;

[0010] (4) Aging and replacement of wet gel: The wet gel obtained in step (3) is added to an aging solution, and the aging solution is replaced every 3 to 12 hours in an oven for aging and replacement;

[0011] (5) Drying the wet gel: The wet gel obtained in step (4) is subjected to supercritical drying to obtain an amorphous precursor of a three-dimensional nanostructure;

[0012] (6) Preparation of high-entropy ceramic composite aerogel: The composite aerogel obtained in step (5) is heat-treated to obtain a fiber-composite high-entropy zirconium-based ceramic aerogel.

[0013] Preferably, the rare earth element ytterbium source, cerium source, yttrium source, thulium source, lutetium source and zirconium source described in step (1) are chlorides or nitrates containing rare earth elements; the molar ratio of anhydrous ethanol to deionized water is 1:(3-10); and the molar ratio of the zirconium source to deionized water is 1:(20-100).

[0014] Preferably, the silicon source described in step (2) is an organic silicon polymer and / or an inorganic silicon compound, such as one or more of tetraethyl orthosilicate, methyl orthosilicate, polysilazane, dimethylchlorosilane or sodium silicate; the molar ratio of deionized water to anhydrous ethanol in the mixed solvent is 1:(1-5); and the molar ratio of the silicon source to deionized water is 1:(4-10).

[0015] Preferably, the spinning aid described in step (2) is one or both of polyvinylpyrrolidone (PVP) and polyvinyl butyral (PVB); the solvent in the spinning aid solution is anhydrous ethanol or deionized water; the molar ratio of the spinning aid to the solvent is 1:(5-15), and the spinning aid solution is prepared by stirring for 12-24 hours; the mass ratio of the spinning aid solution to the silicon solution is 1:(1-3), and the solution is stirred for 4-8 hours until it is evenly mixed.

[0016] The preferred parameters for electrospinning in step (2) are: applying a voltage of 15 to 20 kV to the device, a syringe injection speed of 1 to 5 ml / h; a heat treatment temperature of 600 to 800° C., and a heat treatment time of 1 to 3 h.

[0017] Preferably, the coagulant described in step (3) is one or both of propylene oxide and epichlorohydrin; the molar ratio of the zirconium source to the coagulant is 1:(2-6); the temperature is controlled at -5-8°C when the coagulant is added; the mass ratio of the silica fiber to the high-entropy zirconate sol is 1:(50-100); and the gelation reaction occurs in an oven temperature of 40-70°C.

[0018] Preferably, the aging liquid in step (4) is anhydrous ethanol or deionized water; and the replacement time is 48 to 72 hours.

[0019] Preferably, the aerogel heat treatment temperature in step (6) is 1000-1400° C., the heating rate is 1-5° C. / min, and the heat treatment time is 1-3 h.

[0020] Beneficial effects:

[0021] (1) The present invention uses aerogel as a precursor, which has high porosity and does not require a ball milling method to prepare high-entropy ceramics, thereby reducing energy consumption and simplifying the preparation process.

[0022] (2) Electrospun fibers are used as aerogel reinforcement to further improve the temperature resistance of high-entropy ceramic aerogels.

[0023] (3) The high-entropy ceramic aerogel prepared by the present invention has good thermal stability at high temperatures, retains a complete block shape and has a low density, which is very important for nano-insulating ceramics used in extreme high-temperature environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is the SEM image of the silica fiber after heat treatment at 800°C in Example 1;

[0025] Figure 2 This is a physical picture of the block high entropy ceramic aerogel after heat treatment in Example 1

[0026] Figure 3 This is the X-ray diffraction pattern of the bulk high entropy ceramic composite aerogel prepared in Example 2

[0027] Figure 4 This is the SEM image of the high entropy ceramic aerogel composite fiber after heat treatment at 1000℃ in Example 3 DETAILED DESCRIPTION

[0028] The present invention will be further described below with reference to examples, but the scope of protection is not limited thereto.

[0029] Example 1

[0030] 0.1 mol of tetraethyl orthosilicate was added to a deionized water and anhydrous ethanol solvent with a molar ratio of 1:1, and the molar ratio of tetraethyl orthosilicate to deionized water was 1:4. After stirring and dissolving, a silicon solution was obtained; 1 mol of PVB spinning aid was added to the anhydrous ethanol solvent, and the molar ratio of the spinning aid to anhydrous ethanol was 1:5. The spinning aid solution was obtained by stirring for 12 hours; 3 g of the silicon solution and the spinning aid solution were mixed in a mass ratio of 1:1 and stirred for 4 hours to obtain a spinning solution; the spinning solution was loaded into a syringe and placed in an electrospinning device to apply a voltage of 15 kV. The syringe injection speed was 1 ml / h. The obtained fiber precursor was placed in a muffle furnace for heat treatment at 800 ° C for 1 hour to obtain silica fiber (such as Figure 1 ); 10 mmol of ZrOCl2·8H2O, 2 mmol each of Yb(NO3)3·6H2O, YCl3·6H2O, CeCl3·6H2O, TmCl3·6H2O, and LuCl3·6H2O were weighed and added to a mixed solvent of anhydrous ethanol and deionized water in a molar ratio of 1:3, and the molar ratio of ZrOCl2·8H2O to deionized water was 1:20; the stirred solution was cooled to -5°C in a water bath, propylene oxide was added (the molar ratio of ZrOCl2·8H2O to propylene oxide was 1:2), and 1 g of silica fiber was immersed in the high-entropy sol at a mass ratio of 1:50. After sealing, the solution was placed in a 40°C oven and allowed to stand to gel. After gelation, the aging solution was placed in anhydrous ethanol, and the aging solution was replaced every 3 hours in a 40 ° C oven for 48 hours. The aging solution was demoulded and subjected to supercritical carbon dioxide drying at a drying temperature of 49 ° C, an inner pressure of 9 MPa, and a drying time of 8 hours to obtain a block of high entropy (Yb 0.2 Ce 0.2 Y 0.2 Tm 0.2 Lu 0.2 )2Zr2O7 ceramic composite aerogel precursor, composite aerogel density is 0.115g / cm 3 Finally, the bulk high entropy ceramic aerogel was heat treated. The composite aerogel was heat treated at 1000℃ with a heating rate of 1℃ / min and a holding time of 3h to obtain a bulk high entropy ceramic composite aerogel material. The aerogel after heat treatment still had a complete structure without damage and had good thermal stability (such as Figure 2 ).

[0031] Example 2

[0032] 0.1 mol of methyl orthosilicate was added to a deionized water and anhydrous ethanol solvent with a molar ratio of 1:5, and the molar ratio of methyl orthosilicate to deionized water was 1:10, and the silicon solution was obtained after stirring and dissolving; 1 mol of PVB spinning aid was added to the anhydrous ethanol solvent, and the molar ratio of the spinning aid to anhydrous ethanol was 1:15, and the spinning aid solution was obtained by stirring for 24 hours; 3 g of the silicon solution and the spinning aid solution were mixed in a mass ratio of 1:3, and the spinning solution was obtained by stirring for 8 hours; the spinning solution was loaded into a syringe and placed in an electrospinning device, and a voltage of 20 kV was applied. The syringe injection speed was 5 ml / h, and the obtained fiber precursor was placed in a muffle furnace for heat treatment at 800 ° C. The heat treatment time was 3 hours to obtain silica fiber; 10 mmol Zr(NO3)4·5H2O, 2 mmol each of Yb(NO3)3·6H2O, YCl3·6H2O, CeCl3·6H2O, TmCl3·6H2O and LuCl3·6H2O were added to a mixed solvent of anhydrous ethanol and deionized water in a molar ratio of 1:10, and the molar ratio of ZrOCl2·8H2O to deionized water was 1:100; the stirred solution was cooled to 8°C in a water bath, and propylene oxide (the molar ratio of ZrOCl2·8H2O to epichlorohydrin was 1:6) was added. 1 g of silica fiber was immersed in the high entropy sol at a mass ratio of 1:100, and the resulting solution was sealed and placed in a 70°C oven to allow it to gel. After gelation, deionized water aging solution was added, and the deionized water aging solution was replaced every 12 hours in a 70℃ oven for 72 hours. The mold was demoulded and subjected to supercritical carbon dioxide drying at a drying temperature of 48℃, an inner pressure of 9MPa, and a drying time of 9 hours to obtain a block of high entropy (Yb 0.2 Ce 0.2 Y 0.2 Tm 0.2 Lu 0.2 )2Zr2O7 ceramic composite aerogel precursor, composite aerogel density is 0.12g / cm 3 Finally, the block high entropy ceramic aerogel was heat treated, and the composite aerogel was heat treated at 1400℃ with a heating rate of 5℃ / min and a holding time of 1h. XRD showed that the high entropy ceramic composite aerogel material (such as Figure 3 ), the aerogel after heat treatment still has a complete structure without damage and has good thermal stability.

[0033] Example 3

[0034] 0.1 mol of polysilazane was added to a deionized water and anhydrous ethanol solvent with a molar ratio of 1:2, and the molar ratio of polysilazane to deionized water was 1:6. After stirring and dissolving, a silicon solution was obtained. 1 mol of PVB spinning aid was added to anhydrous ethanol solvent, and the molar ratio of the spinning aid to anhydrous ethanol was 1:10. The spinning aid solution was obtained by stirring for 15 hours. 3 g of the silicon solution and the spinning aid solution were mixed in a mass ratio of 1:2, and stirred for 5 hours to obtain a spinning solution. The spinning solution was loaded into a syringe and placed in an electrospinning device, and a voltage of 20 kV was applied. The syringe injection speed was 1.2 ml / h. The obtained fiber precursor was placed in a muffle furnace for heat treatment at 700 ° C for 1 hour to obtain silica fiber. 10 mmol was weighed. ZrOCl2·8H2O, 2 mmol each of Yb(NO3)3·6H2O, YCl3·6H2O, Ce(NO3)3·6H2O, TmCl3·6H2O and LuCl3·6H2O were added to a mixed solvent of anhydrous ethanol and deionized water in a molar ratio of 1:5, and the molar ratio of ZrOCl2·8H2O to deionized water was 1:40; the stirred solution was cooled to -2°C in a water bath, and propylene oxide was added (the molar ratio of ZrOCl2·8H2O to propylene oxide was 1:4). 1 g of silica fiber was immersed in the high-entropy sol at a mass ratio of 1:70, and the solution was sealed and placed in a 50°C oven to allow it to gel. After gelation, the aging solution was placed in anhydrous ethanol, and the aging solution was replaced every 6 hours in a 50℃ oven for 64 hours. The aging solution was demoulded and dried in supercritical carbon dioxide at a drying temperature of 50℃, an autoclave pressure of 10MPa, and a drying time of 8 hours to obtain a block of high entropy (Yb 0.2 Ce 0.2 Y 0.2 Tm 0.2 Lu 0.2 )2Zr2O7 ceramic composite aerogel precursor, the composite aerogel density is 0.115g / cm3, and finally the block high entropy ceramic aerogel is heat treated at 1000℃, the heating rate is 2℃ / min, and the holding time is 2h to obtain the block high entropy ceramic composite aerogel material (such as Figure 4 ), the aerogel after heat treatment still has a complete structure without damage and has good thermal stability.

[0035] Example 4

[0036] 0.1 mol of dimethylchlorosilane was added to a deionized water and anhydrous ethanol solvent with a molar ratio of 1:4, and the molar ratio of dimethylchlorosilane to deionized water was 1:8. After stirring and dissolving, a silicon solution was obtained; 1 mol of PVB spinning aid was added to anhydrous ethanol solvent, and the molar ratio of the spinning aid to anhydrous ethanol was 1:12. The spinning aid solution was obtained by stirring for 20 hours; 3 g of the silicon solution and the spinning aid solution were mixed in a mass ratio of 1:1, and stirred for 6 hours to obtain a spinning solution; the spinning solution was loaded into a syringe and placed in an electrospinning device, and an 18 kV voltage was applied. The syringe injection speed was 3 ml / h. The obtained fiber precursor was placed in a muffle furnace for heat treatment at 800 ° C. The heat treatment time was 2 hours to obtain silica fiber; 10 mmol was weighed. ZrOCl2·8H2O, 2 mmol each of Yb(NO3)3·6H2O, Y(NO3)3·6H2O, Ce(NO3)3·6H2O, TmCl3·6H2O and LuCl3·6H2O were added to a mixed solvent of anhydrous ethanol and deionized water in a molar ratio of 1:5, and the molar ratio of ZrOCl2·8H2O to deionized water was 1:80; the stirred solution was cooled to 0°C in a water bath, and propylene oxide was added (the molar ratio of ZrOCl2·8H2O to propylene oxide was 1:5). 1 g of silica fiber was immersed in the high entropy sol at a mass ratio of 1:90, and the solution was sealed and placed in a 60°C oven to allow it to gel. After gelation, the aging solution was placed in anhydrous ethanol, and the aging solution was replaced every 10 hours in a 60℃ oven for 48 hours. The aging solution was demoulded and subjected to supercritical carbon dioxide drying at a drying temperature of 50℃, an autoclave pressure of 9MPa, and a drying time of 8 hours to obtain a block of high entropy (Yb 0.2 Ce 0.2 Y 0.2 Tm 0.2 Lu 0.2 )2Zr2O7 ceramic composite aerogel precursor, composite aerogel density is 0.125g / cm 3 Finally, the bulk high-entropy ceramic aerogel was heat-treated, and the composite aerogel was heat-treated at 1200°C with a heating rate of 3°C / min and a holding time of 1h to obtain a bulk high-entropy ceramic composite aerogel material. The aerogel after heat treatment still has a complete structure without damage and has good thermal stability.

[0037] Example 5

[0038] 0.1 mol of sodium silicate was added to a deionized water and anhydrous ethanol solvent with a molar ratio of 1:4, and the molar ratio of sodium silicate to deionized water was 1:8. After stirring and dissolving, a silicon solution was obtained. 1 mol of PVB spinning aid was added to anhydrous ethanol solvent, and the molar ratio of the spinning aid to anhydrous ethanol was 1:12. The spinning aid solution was obtained by stirring for 20 hours. 3 g of silicon solution and the spinning aid solution were mixed in a mass ratio of 1:1, and stirred for 6 hours to obtain a spinning solution. The spinning solution was loaded into a syringe and placed in an electrospinning device, and a voltage of 19 kV was applied. The syringe injection speed was 4 ml / h. The obtained fiber precursor was placed in a muffle furnace for heat treatment at 800 ° C. The heat treatment time was 2 hours to obtain silica fiber. 10 mmol was weighed. Zr(NO3)4·5H2O, 2 mmol each of Yb(NO3)3·6H2O, YCl3·6H2O, Ce(NO3)3·6H2O, TmCl3·6H2O and LuCl3·6H2O were added to a mixed solvent of anhydrous ethanol and deionized water in a molar ratio of 1:7, and the molar ratio of Zr(NO3)4·5H2O to deionized water was 1:80; the stirred solution was cooled to 2°C in a water bath, and propylene oxide was added (the molar ratio of ZrOCl2·8H2O to propylene oxide was 1:5). 1 g of silica fiber was immersed in the high entropy sol at a mass ratio of 1:60, and the resulting solution was sealed and placed in a 60°C oven to allow it to gel. After gelation, the aging solution was placed in anhydrous ethanol, and the aging solution was replaced every 8 hours in a 60℃ oven for 64 hours. The aging solution was demoulded and subjected to supercritical carbon dioxide drying at a drying temperature of 49℃, an inner pressure of 10MPa, and a drying time of 9 hours to obtain a block of high entropy (Yb 0.2 Ce 0.2 Y 0.2 Tm 0.2 Lu 0.2 )2Zr2O7 ceramic composite aerogel precursor, the composite aerogel density is 0.128g / cm 3 Finally, the bulk high-entropy ceramic aerogel was heat-treated. The composite aerogel was heat-treated at 1300°C with a heating rate of 3°C / min and a holding time of 3h to obtain a bulk high-entropy ceramic composite aerogel material. The aerogel after heat treatment still has a complete structure without damage and has good thermal stability.

[0039] Example 6

[0040] 0.1 mol of tetraethyl orthosilicate was added to a deionized water and anhydrous ethanol solvent with a molar ratio of 1:4, and the molar ratio of tetraethyl orthosilicate to deionized water was 1:9. After stirring and dissolving, a silicon solution was obtained; 1 mol of PVB spinning aid was added to anhydrous ethanol solvent, and the molar ratio of the spinning aid to anhydrous ethanol was 1:13. The spinning aid solution was obtained by stirring for 21 hours; 3 g of the silicon solution and the spinning aid solution were mixed in a mass ratio of 1:3, and stirred for 7 hours to obtain a spinning solution; the spinning solution was loaded into a syringe and placed in an electrospinning device, and a voltage of 16 kV was applied. The syringe injection speed was 3 ml / h. The obtained fiber precursor was placed in a muffle furnace for heat treatment at 700 ° C. The heat treatment time was 3 hours to obtain silica fiber; 10 mmol was weighed. ZrOCl2·8H2O, 2 mmol each of Yb(NO3)3·6H2O, YCl3·6H2O, Ce(NO3)3·6H2O, TmCl3·6H2O and LuCl3·6H2O were added to a mixed solvent of anhydrous ethanol and deionized water in a molar ratio of 1:9, and the molar ratio of ZrOCl2·8H2O to deionized water was 1:70; the stirred solution was cooled to 6°C in a water bath, and propylene oxide was added (the molar ratio of ZrOCl2·8H2O to propylene oxide was 1:3). 1 g of silica fiber was immersed in the high-entropy sol at a mass ratio of 1:60, and the solution was sealed and placed in a 60°C oven to allow it to gel. After gelation, the aging solution was placed in anhydrous ethanol, and the aging solution was replaced every 10 hours in a 60 ° C oven for 72 hours. The aging solution was demoulded and subjected to supercritical carbon dioxide drying at a drying temperature of 49 ° C, an inner pressure of 10 MPa, and a drying time of 10 hours to obtain a block of high entropy (Yb 0.2 Ce 0.2 Y 0.2 Tm 0.2 Lu 0.2 )2Zr2O7 ceramic composite aerogel precursor, the composite aerogel density is 0.118g / cm 3 Finally, the bulk high-entropy ceramic aerogel was heat-treated. The composite aerogel was heat-treated at 1200°C with a heating rate of 3°C / min and a holding time of 3h to obtain a bulk high-entropy ceramic composite aerogel material. The aerogel after heat treatment still has a complete structure without damage and has good thermal stability.

Claims

1. A method for preparing a fiber-composite high-entropy zirconium-based ceramic aerogel material, the specific steps of which are as follows: (1) Preparation of high entropy sol: According to the chemical formula (Yb 0.2 Ce 0.2 Y 0.2 Tm 0.2 Lu 0.2 )2Zr2O7 molar ratio of rare earth elements ytterbium source, cerium source, yttrium source, thulium source, lutetium source and zirconium source are weighed, anhydrous ethanol or deionized water mixed solvent is added, and stirred until completely dissolved to obtain a hydrolyzed sol; (2) Preparation of silica fiber: dissolving a silicon source in a mixed solvent of anhydrous ethanol and deionized water to prepare a silicon solution; dissolving a spinning aid in the solvent to prepare a spinning aid solution; stirring and mixing the silicon solution and the spinning aid solution to obtain a spinning solution, obtaining silica precursor fibers by electrospinning, and then placing the precursor fibers in a box furnace for heat treatment to obtain silica fibers; (3) Preparation of composite aerogel: a coagulant is introduced into the sol obtained in step (1) under temperature control conditions to obtain a high-entropy zirconate sol; the silica fiber obtained in step (2) is then immersed in the high-entropy zirconate sol that has not formed a gel, and the fiber is placed in an oven and allowed to stand to undergo a gelation reaction to obtain a wet gel; (4) Aging and replacement of wet gel: The wet gel obtained in step (3) is added to an aging solution, and the aging solution is replaced every 3 to 12 hours in an oven for aging and replacement; (5) Drying the wet gel: The wet gel obtained in step (4) is subjected to supercritical drying to obtain an amorphous precursor of a three-dimensional nanostructure; (6) Preparation of high-entropy ceramic composite aerogel: The composite aerogel obtained in step (5) is heat-treated to obtain a fiber-composite high-entropy zirconium-based ceramic aerogel.

2. The preparation method according to claim 1, wherein The rare earth element ytterbium source, cerium source, yttrium source, thulium source, lutetium source and zirconium source described in step (1) are chlorides or nitrates containing rare earth elements; the molar ratio of anhydrous ethanol to deionized water is 1:(3-10); and the molar ratio of the zirconium source to deionized water is 1:(20-100).

3. The preparation method according to claim 1, wherein The silicon source described in step (2) is one or more of tetraethyl orthosilicate, methyl orthosilicate, polysilazane, dimethylchlorosilane or sodium silicate; the molar ratio of deionized water to anhydrous ethanol in the mixed solvent is 1:(1-5); and the molar ratio of the silicon source to deionized water is 1:(4-10).

4. The preparation method according to claim 1, characterized in that The spinning aid described in step (2) is one or both of polyvinylpyrrolidone (PVP) and polyvinyl butyral (PVB); the solvent in the spinning aid solution is anhydrous ethanol or deionized water; the molar ratio of the spinning aid to the solvent is 1:(5-15), and the spinning aid solution is prepared by stirring for 12-24 hours; the mass ratio of the spinning aid solution to the silicon solution is 1:(1-3), and the solution is stirred for 4-8 hours until it is evenly mixed.

5. The preparation method according to claim 1, characterized in that The electrospinning parameters in step (2) are: 15-20 kV voltage is applied to the equipment, the syringe injection speed is 1-5 ml / h; the heat treatment temperature is 600-800° C., and the heat treatment time is 1-3 h.

6. The preparation method according to claim 1, characterized in that The coagulant described in step (3) is one or both of propylene oxide and epichlorohydrin; the molar ratio of the zirconium source to the coagulant is 1:(2-6); the temperature is controlled at -5-8°C when the coagulant is added; the mass ratio of the silica fiber to the high-entropy zirconate sol is 1:(50-100); and the oven temperature is 40-70°C.

7. The method according to claim 1, characterized in that The aging liquid in step (4) is anhydrous ethanol or deionized water; the replacement time is 48 to 72 hours.

8. The method according to claim 1, characterized in that The aerogel heat treatment temperature described in step (6) is 1000-1400° C., the heating rate is 1-5° C. / min, and the heat treatment time is 1-3 h.

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