Yttrium-silicon reinforced zirconium aerogel and method of making same
By preparing yttrium silicon composite zirconium gel, the problem of poor mechanical durability of zirconium oxide aerogel at high temperature was solved, and the high temperature stability and thermal insulation performance were improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANDONG RES & DESIGN ACADEMY OF IND CERAMICS
- Filing Date
- 2023-10-19
- Publication Date
- 2026-07-24
AI Technical Summary
Zirconia aerogel has poor mechanical durability at high temperatures and undergoes large phase transformations, which affects its application in high-temperature insulation.
By preparing yttrium-silicon composite zirconium gel, and using steps such as aging of silica sol and zirconium-yttrium composite sol and supercritical drying, yttrium-silicon reinforced zirconium aerogel was prepared, thereby improving its mechanical strength and stability.
With a thermal conductivity of ≤0.085W/m·k at 1200℃ and a volume shrinkage rate of 4-9% after heat treatment for 30 min, the mechanical strength and chemical stability of the aerogel are significantly improved, avoiding deformation and shrinkage at high temperatures.
Abstract
Description
Technical Field
[0001] This invention relates to the field of aerogel technology, and more specifically to a yttrium silicon reinforced zirconium aerogel and its preparation method. Background Technology
[0002] High-temperature resistant aerogel insulation is used in various advanced protection systems, serving as a crucial guarantee for the safe operation of equipment and a key material for the development of low-carbon and energy-saving technologies to meet higher requirements. ZrO2 possesses technical characteristics such as high melting point, oxidation resistance, low intrinsic thermal conductivity, and strong infrared shielding, making ZrO2 aerogel composites highly promising for high-temperature insulation applications. However, zirconia aerogels exhibit poor mechanical durability, and their large phase transformation at high temperatures (above 1000℃) hinders their development. Combining silicon dioxide with zirconia aerogels can significantly improve these shortcomings. Therefore, exploring suitable doping reinforcement methods to improve the mechanical strength, mechanical stability, and chemical stability of ZrO2 aerogels while ensuring high insulation performance, and avoiding the problem of large shrinkage at high temperatures, has become a pressing challenge in this field. Summary of the Invention
[0003] The purpose of this invention is to solve the above-mentioned problems by proposing a yttrium silicon reinforced zirconium aerogel and its preparation method. The prepared yttrium silicon reinforced zirconium aerogel has high temperature stability, with a thermal conductivity of ≤0.085W / m•k at 1200℃, and a volume shrinkage rate of 4-9% of the original volume after heat treatment at 1200℃ for 30 min.
[0004] Preferably, the thermal conductivity at 1200℃ is ≤0.070W / m•k, and the volume shrinkage rate after heat treatment at 1200℃ for 30min is 4-6% of the original volume.
[0005] To achieve the above objectives, according to one aspect of the present invention, a method for preparing yttrium silicon-reinforced zirconium aerogel is provided, comprising the following steps: preparing silica sol and zirconium-yttrium composite sol; and preparing yttrium silicon-reinforced zirconium aerogel based on the silica sol and zirconium-yttrium composite sol.
[0006] The yttrium silicon-zirconium composite gel was aged in an aging solvent at an aging temperature of 25-60°C.
[0007] The aged yttrium silicon-zirconium composite gel was subjected to supercritical drying through a drying medium to obtain the yttrium silicon-reinforced zirconium aerogel.
[0008] The aging solvent includes one or more of ethanol, tetraethyl orthosilicate, and heptane, and the volume ratio of the aging solvent to the yttrium silicon-zirconium composite gel is (1-2):1.
[0009] The drying medium includes ethanol, and the supercritical drying temperature is 260-280℃.
[0010] Preferably, the drying steps are as follows: the blocky wet gel is placed in a supercritical drying vessel, nitrogen gas is introduced at 3-4 MPa, the temperature of the autoclave is raised to 260-280℃, and the pressure is raised to 8-10 MPa.
[0011] After maintaining the pressure for 1-3 hours, drain the alcohol from the high-pressure reactor at a rate of 20-100 kPa / min.
[0012] Finally, the autoclave was allowed to cool naturally to room temperature, and the sample was then removed, which was a high-temperature resistant yttrium silicon reinforced zirconium aerogel.
[0013] Compared with existing technologies, its advantages lie in the fact that by preparing yttrium-silicon composite zirconium gel through the silica sol and zirconium-yttrium composite sol, silicon aerogel and yttrium aerogel are doped into the zirconium aerogel; this facilitates the preparation of composite aerogels with better stability, mechanical strength, and mechanical durability, as well as good thermal insulation performance; it helps to avoid deformation of zirconium aerogels when the operating temperature exceeds 1000℃; the aging temperature is 25-39℃; the aging solvent includes one or more of ethanol, tetraethyl orthosilicate, and heptane; it achieves uniform cross-linking within the yttrium-silicon composite zirconium gel, and also facilitates the replacement of water in the internal pores of the yttrium-silicon composite zirconium gel with tetraethyl orthosilicate and heptane, further facilitating the avoidance of deformation or changes in the internal pores and mesh structure of the aerogel due to traction when substances in the pores are discharged during subsequent supercritical drying.
[0014] Furthermore, the process for preparing silica sol is as follows: dissolve silanol salt in an alcohol-water mixed solvent to obtain a silanol salt solution, and then add an acidic catalyst to adjust the pH value to obtain silica sol;
[0015] And / or, the process for preparing zirconium-yttrium composite sol is as follows: dissolve zirconium precursor and yttrium precursor in an alcohol-water mixed solvent to obtain a zirconium-yttrium precursor solution, and then add an amide catalyst to the zirconium-yttrium precursor solution to react and obtain zirconium-yttrium composite sol.
[0016] The beneficial effect of adopting the above-mentioned further technical solution is that it prepares silica sol and zirconium-yttrium composite sol.
[0017] Furthermore, the process for preparing the yttrium silicon-zirconium composite gel is as follows: after mixing silica sol with zirconium-yttrium composite sol, a first gel catalyst is added to obtain the yttrium silicon-zirconium composite gel.
[0018] Furthermore, the volume ratio of alcohol to water in the alcohol-water mixed solvent is (0.5-1.8):1; when preparing silica sol using a silanol solution and an acidic catalyst, the temperature is controlled at 50-60℃, and the concentration of silanol in the silanol solution is 0.5-1.5 mol / L; the pH of the silica sol is 2-5; when preparing zirconium-yttrium composite sol using a zirconium-yttrium precursor solution and an amide catalyst, the temperature is controlled at 25-50℃, the concentration of zirconium precursor in the zirconium-yttrium precursor solution is 0.15-0.5 mol / L, and the concentration of yttrium precursor in the zirconium-yttrium precursor solution is 0.02-0.06 mol / L; the pH of the zirconium-yttrium composite sol is 2-5.
[0019] Furthermore, the first gel catalyst comprises one or a mixture of several of ethylene oxide, propylene oxide, and butane oxide; the molar ratio of the first gel catalyst to the zirconium precursor is 1:(3-5); the molar ratio of the silanol, zirconium precursor, and yttrium precursor is (2.5-3.5):(9-10):1.
[0020] The beneficial effect of adopting the above-mentioned further technical solution is that by first mixing the silica sol with the zirconium-yttrium composite sol and then adding the first gel catalyst to obtain the yttrium-silicon composite zirconium gel, the operation is simple and it is conducive to achieving a uniform internal structure of the yttrium-silicon composite zirconium gel.
[0021] Furthermore, the process for preparing the yttrium-silicon-zirconium composite gel is as follows: adding silica sol to a second gel catalyst to obtain a primary reactive silica sol; mixing the primary reactive silica sol with the zirconium-yttrium composite sol, and then adding a first gel catalyst to obtain the yttrium-silicon-zirconium composite gel.
[0022] Furthermore, the volume ratio of alcohol to water in the alcohol-water mixed solvent is (0.5-1.0):1; when preparing silica sol using a silanol solution and an acidic catalyst, the temperature is controlled at 65-75℃, and the concentration of silanol in the silanol solution is 0.5-1.0 mol / L; the pH of the silica sol is 2-3; when preparing zirconium-yttrium composite sol using a zirconium-yttrium precursor solution and an amide catalyst, the temperature is controlled at 60-75℃, the concentration of zirconium precursor in the zirconium-yttrium precursor solution is 0.35-0.5 mol / L, and the concentration of yttrium precursor in the zirconium-yttrium precursor solution is 0.02-0.04 mol / L; the pH of the zirconium-yttrium composite sol is 2-3.
[0023] Furthermore, the first gel catalyst comprises one or a mixture of several of ethylene oxide, propylene oxide, and butane oxide;
[0024] The second gel catalyst includes one or more of ammonia, tetramethylammonium hydroxide, and dimethylaminoethanol;
[0025] The molar ratio of the second gel catalyst, silanol, first gel catalyst, zirconium precursor, and yttrium precursor is (10-15):(0.5-5):(1-5):(8-20):(0.5-5).
[0026] The advantages of the previous step are that by first pre-gelling the silica sol to obtain the primary reaction silica sol, and then adding the first gel catalyst to obtain the yttrium silicon-zirconium composite gel, the amount of the first gel added is significantly reduced, which effectively reduces the production cost. Furthermore, by using stepwise gelation, the problem of short molecular chains in the network structure during cross-linking can be avoided, which further helps to improve the cross-linking strength and the mechanical strength of the aerogel.
[0027] By reducing the alcohol content in the alcohol-water mixed solvent, it is beneficial to avoid anomalies when increasing the temperature of the silanol solution and the zirconium-yttrium precursor solution.
[0028] Increasing the temperature of the silanol solution helps avoid the problem of a significant decrease in crosslinking rate when the concentration of the silanol solution decreases and the alcohol content decreases. At the same time, it helps to reduce the viscosity of the primary reaction silica sol when it reaches the preset degree of crosslinking, which helps to ensure uniform mixing and reaction when the primary reaction silica sol is mixed with zirconium yttrium composite sol and gelled.
[0029] Controlling the pH of silica sol to be low can help improve its catalytic efficiency. However, in order to avoid the problem of silica sol solidifying after partial gelation or having high viscosity, which is not conducive to the mixing of silica sol and zirconium-yttrium composite sol in subsequent primary reactions;
[0030] Using a zirconium-yttrium precursor solution with a concentration of 0.35-0.5 mol / L, which is relatively high, is beneficial for improving the initiation efficiency of the first gel initiator and reducing the moisture content of the final gel, thereby improving the efficiency of subsequent drying and supercritical drying.
[0031] Furthermore, the zirconium precursor includes zirconium oxychloride octahydrate or zirconium oxynitrate; the yttrium precursor includes yttrium nitrate hexahydrate or yttrium chloride hexahydrate;
[0032] And / or, the aging solvent further includes hexamethyldisiloxane, wherein the volume ratio of hexamethyldisiloxane, tetraethyl orthosilicate, and ethanol in the aging solvent is (10-40):1:(5-20).
[0033] The beneficial effect of the previous step is that the aging solvent also includes hexamethyldisiloxane, which helps to replace the water in the pores of the yttrium silicon-zirconium composite gel with hexamethyldisiloxane. This further helps to avoid the problem of deformation or change of the pores and grid structure of the aerogel due to traction when the substances in the pores are discharged during subsequent supercritical drying.
[0034] According to one aspect of the present invention, a yttrium silicon reinforced zirconium aerogel is provided, which is prepared according to a method for preparing yttrium silicon reinforced zirconium aerogel.
[0035] Compared with existing technologies, its advantages lie in the fact that the yttrium silicon reinforced zirconium aerogel has high mechanical strength and mechanical stability, chemical stability at high temperatures and is not easily deformed, and has a small shrinkage rate; the thermal conductivity of the yttrium silicon reinforced zirconium aerogel at 1200℃ is ≤0.085W / m•k, and the volume shrinkage rate after heat treatment at 1200℃ for 30min is 4-9% of the original volume;
[0036] Ideally, the thermal conductivity at 1200℃ is ≤0.070W / m•k, and the volume shrinkage rate after heat treatment at 1200℃ for 30min is 4-6% of the original volume. Detailed Implementation
[0037] To better understand the technical solution of the present invention, the present invention will be further described below in conjunction with specific embodiments.
[0038] Example 1:
[0039] This embodiment provides a method for preparing yttrium silicon reinforced zirconium aerogel, comprising the following steps:
[0040] Silica sol and zirconium-yttrium composite sol were prepared by dissolving a silanol solution in an alcohol-water mixed solvent to obtain a silanol solution, and then adding an acidic catalyst to adjust the pH value to obtain silica sol.
[0041] The process for preparing zirconium-yttrium composite sol is as follows: zirconium precursor and yttrium precursor are dissolved in an alcohol-water mixed solvent to obtain a zirconium-yttrium precursor solution, and then an amide catalyst is added to the zirconium-yttrium precursor solution to react and obtain zirconium-yttrium composite sol.
[0042] The zirconium precursor includes zirconium oxychloride octahydrate; the yttrium precursor includes yttrium nitrate hexahydrate.
[0043] The alcohol-water mixed solvent has an alcohol-to-water volume ratio of 1.7:1; the temperature of the silanol solution is adjusted to 55°C, and the concentration of silanol in the silanol solution is 1 mol / L; the pH of the silica sol is 3.5.
[0044] The temperature of the zirconium-yttrium precursor solution was adjusted to 37°C, the concentration of zirconium precursor in the zirconium-yttrium precursor solution was 0.32 mol / L, and the concentration of yttrium precursor in the zirconium-yttrium precursor solution was 0.04 mol / L; the pH of the zirconium-yttrium composite sol was 3.5.
[0045] Yttrium-silicon composite zirconium gel was prepared based on the silica sol and zirconium-yttrium composite sol. The process of preparing the yttrium-silicon composite zirconium gel is as follows: silica sol is added to zirconium-yttrium composite sol and mixed, and then a first gel catalyst is added to obtain the yttrium-silicon composite zirconium gel.
[0046] The first gel catalyst comprises ethylene oxide; the molar ratio of the first gel catalyst to the zirconium precursor is 1:4; the molar ratio of the silanol, zirconium precursor, and yttrium precursor is 3:9.5:1.
[0047] The yttrium silicon-zirconium composite gel was aged in an aging solvent at a temperature of 43°C; the aging solvent included one or more of ethanol, tetraethyl orthosilicate, and heptane; the volume ratio of the aging solvent to the yttrium silicon-zirconium composite gel was 1.5:1.
[0048] The aged yttrium silicon-zirconium composite gel was subjected to supercritical drying through a drying medium to obtain the yttrium silicon-reinforced zirconium aerogel.
[0049] The drying medium includes ethanol, and the supercritical drying temperature is 270℃. The drying steps are as follows: the blocky wet gel is placed in a supercritical drying vessel containing the drying medium, and nitrogen gas at 3.5 MPa is introduced. The temperature of the high-pressure vessel is raised to 270℃, and the pressure is raised to 9 MPa. After maintaining this temperature for 2 hours, the drying medium in the high-pressure vessel is discharged at a rate of 60 kPa / min. Finally, the high-pressure vessel is allowed to cool naturally to room temperature, and the sample is taken out as yttrium silicon reinforced zirconium aerogel. The thermal conductivity of the yttrium silicon reinforced zirconium aerogel at 1200℃ is 0.080 W / m•k, and the volume shrinkage rate after heat treatment at 1200℃ for 30 min is 7% of the original volume.
[0050] Another aspect of this embodiment provides a yttrium silicon reinforced zirconium aerogel, prepared according to a method for preparing yttrium silicon reinforced zirconium aerogel.
[0051] Example 2:
[0052] The same content as in Example 1 will not be repeated here; the difference between this embodiment and Example 1 is that this embodiment provides a method for preparing yttrium silicon-reinforced zirconium aerogel, wherein the zirconium precursor includes zirconium oxynitrate; and the yttrium precursor includes yttrium chloride hexahydrate.
[0053] The alcohol-water mixed solvent has an alcohol-to-water volume ratio of 0.75:1; the temperature of the silanol solution is adjusted to 70°C, and the concentration of the silanol in the silanol solution is 0.75 mol / L; the pH of the silica sol is 2.5; the temperature of the zirconium-yttrium precursor solution is adjusted to 67°C, and the concentration of the zirconium precursor in the zirconium-yttrium precursor solution is 0.43 mol / L, and the concentration of the yttrium precursor in the zirconium-yttrium precursor solution is 0.03 mol / L; the pH of the zirconium-yttrium composite sol is 2.5.
[0054] The process for preparing yttrium-silicon-zirconium composite gel is as follows: silica sol is added to a second gel catalyst to obtain a primary reactive silica sol; the primary reactive silica sol is mixed with a zirconium-yttrium composite sol, and then a first gel catalyst is added to obtain the yttrium-silicon-zirconium composite gel.
[0055] The first gel catalyst comprises cyclopropane; the second gel catalyst comprises ammonia.
[0056] The molar ratio of the second gel catalyst, silanol, first gel catalyst, zirconium precursor, and yttrium precursor is 12:2.7:2:14:2.7.
[0057] The yttrium silicon-zirconium composite gel was aged in an aging solvent at a temperature of 43°C. The aging solvent also included hexamethyldisiloxane, and the volume ratio of hexamethyldisiloxane, tetraethyl orthosilicate, and ethanol in the aging solvent was 25:1:13.
[0058] The drying medium includes carbon dioxide, and the supercritical drying temperature is 275℃. The drying steps are as follows: the blocky wet gel is placed in a supercritical drying vessel containing the drying medium, nitrogen gas is introduced at 3.2 MPa, the temperature of the autoclave is raised to 275℃, and the pressure is raised to 8.8 MPa. After maintaining this temperature for 2 hours, the drying medium in the autoclave is discharged at a rate of 30 kPa / min. Finally, the autoclave is allowed to cool naturally to room temperature, and the sample is taken out as yttrium silicon reinforced zirconium aerogel. The thermal conductivity of the yttrium silicon reinforced zirconium aerogel at 1200℃ is 0.075 W / m•k, and the volume shrinkage rate after heat treatment at 1200℃ for 30 min is 5% of the original volume.
[0059] Another aspect of this embodiment provides a yttrium silicon reinforced zirconium aerogel, prepared according to a method for preparing yttrium silicon reinforced zirconium aerogel.
[0060] Example 3:
[0061] The features that are the same as those in Example 2 will not be repeated here. The features that are different from those in Example 2 are: This example provides a method for preparing yttrium silicon-reinforced zirconium aerogel, wherein the zirconium precursor includes zirconium oxychloride octahydrate; and the yttrium precursor includes yttrium nitrate hexahydrate.
[0062] The volume ratio of alcohol to water in the alcohol-water mixed solvent is 0.6:1;
[0063] The temperature of the silanol solution was adjusted to 73°C, and the concentration of silanol in the solution was 0.6 mol / L; the pH of the silica sol was 2.2.
[0064] The temperature of the zirconium-yttrium precursor solution was adjusted to 73°C, the concentration of zirconium precursor in the zirconium-yttrium precursor solution was 0.48 mol / L, and the concentration of yttrium precursor in the zirconium-yttrium precursor solution was 0.038 mol / L; the pH of the zirconium-yttrium composite sol was 2.2.
[0065] The process for preparing yttrium-silicon-zirconium composite gel is as follows: silica sol is added to a second gel catalyst to obtain a primary reactive silica sol; the primary reactive silica sol is mixed with a zirconium-yttrium composite sol, and then a first gel catalyst is added to obtain the yttrium-silicon-zirconium composite gel.
[0066] The first gel catalyst comprises a mixture of ethylene oxide and butylene oxide; the second gel catalyst comprises tetramethylammonium hydroxide;
[0067] The molar ratio of the second gel catalyst, silanol, first gel catalyst, zirconium precursor, and yttrium precursor is 14:4:1.8:18:0.8.
[0068] The yttrium silicon-zirconium composite gel was aged in an aging solvent at a temperature of 30°C. The aging solvent also included hexamethyldisiloxane, and the volume ratio of hexamethyldisiloxane, tetraethyl orthosilicate, and ethanol in the aging solvent was 15:1:18.
[0069] The drying medium includes ethanol, and the supercritical drying temperature is 270℃. The drying steps are as follows: the block-shaped wet gel is placed in a supercritical drying reactor containing the drying medium, nitrogen gas is introduced at 3.8 MPa, the temperature of the high-pressure reactor is raised to 265℃, and the pressure is raised to 9.5 MPa. After maintaining this temperature for 2 hours, the drying medium in the high-pressure reactor is discharged at a rate of 80 kPa / min. Finally, the high-pressure reactor is allowed to cool naturally to room temperature, and the sample taken out is yttrium silicon reinforced zirconium aerogel.
[0070] The yttrium silicon reinforced zirconium aerogel obtained at 1200℃ has a thermal conductivity of 0.070 W / m•k and a volume shrinkage rate of 4.5% of the original volume after heat treatment at 1200℃ for 30 min.
[0071] Another aspect of this embodiment provides a yttrium silicon reinforced zirconium aerogel, prepared according to a method for preparing yttrium silicon reinforced zirconium aerogel.
[0072] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, the above-described features have similar functions to (but are not limited to) those disclosed in this application.
Claims
1. A method for preparing yttrium silicon reinforced zirconium aerogel, characterized in that, Includes the following steps: Preparation of silica sol and zirconium-yttrium composite sol; The process for preparing silica sol is as follows: dissolve silanol salts in a mixed solvent of alcohol and water to obtain a silanol salt solution, and then add an acidic catalyst to adjust the pH value to obtain silica sol; The process for preparing zirconium-yttrium composite sol is as follows: zirconium precursor and yttrium precursor are dissolved in an alcohol-water mixed solvent to obtain a zirconium-yttrium precursor solution, and then an amide catalyst is added to the zirconium-yttrium precursor solution to react and obtain zirconium-yttrium composite sol. Yttrium-silicon composite zirconium gel was prepared based on the aforementioned silica sol and zirconium-yttrium composite sol. The process for preparing yttrium silicon-zirconium composite gel is as follows: adding silica sol to a second gel catalyst to obtain a primary reactive silica sol; mixing the primary reactive silica sol with a zirconium-yttrium composite sol, and then adding a first gel catalyst to obtain the yttrium silicon-zirconium composite gel; The volume ratio of alcohol to water in the alcohol-water mixed solvent is (0.5-1.0):1; When preparing silica sol using a silanol solution and an acidic catalyst, the temperature is controlled at 65-75℃, the concentration of silanol in the silanol solution is 0.5-1.0 mol / L, and the pH of the silica sol is 2-3. In the preparation of zirconium-yttrium composite sol via zirconium-yttrium precursor solution and amide catalyst, the temperature is controlled at 60-75℃, the concentration of zirconium precursor in the zirconium-yttrium precursor solution is 0.35-0.5 mol / L, the concentration of yttrium precursor in the zirconium-yttrium precursor solution is 0.02-0.04 mol / L, and the pH of the zirconium-yttrium composite sol is 2-3. The yttrium silicon-zirconium composite gel was aged in an aging solvent at an aging temperature of 25-60°C. The aged yttrium silicon-zirconium composite gel was subjected to supercritical drying through a drying medium to obtain the yttrium silicon-reinforced zirconium aerogel. The aging solvent includes one or more of ethanol, tetraethyl orthosilicate, and heptane, and the volume ratio of the aging solvent to the yttrium silicon-zirconium composite gel is (1-2):
1. The drying medium includes ethanol, and the supercritical drying temperature is 260-280℃.
2. The method for preparing yttrium silicon reinforced zirconium aerogel according to claim 1, characterized in that, The first gel catalyst comprises one or a mixture of several of ethylene oxide, propylene oxide, and butane oxide; The second gel catalyst includes one or more of ammonia, tetramethylammonium hydroxide, and dimethylaminoethanol; The molar ratio of the second gel catalyst, silanol, first gel catalyst, zirconium precursor, and yttrium precursor is (10-15):(0.5-5):(1-5):(8-20):(0.5-5).
3. The method for preparing yttrium silicon reinforced zirconium aerogel according to claim 1, characterized in that, The zirconium precursor includes zirconium oxychloride octahydrate or zirconium oxynitrate; the yttrium precursor includes yttrium nitrate hexahydrate or yttrium chloride hexahydrate. and / or The aging solvent also includes hexamethyldisiloxane, and the volume ratio of hexamethyldisiloxane, tetraethyl orthosilicate, and ethanol in the aging solvent is (10-40): 1: (5-20).
4. A yttrium silicon reinforced zirconium aerogel, characterized in that, The yttrium silicon reinforced zirconium aerogel was prepared according to any one of claims 1-3.