Preparation method of a lightweight rigid frame reinforced aerogel ceramic thermal insulation composite material with high strength, super hydrophobicity and high temperature resistance

Abstract

A method for preparing a lightweight rigid frame reinforced aerogel ceramic thermal insulation composite material with high strength, super hydrophobicity and high temperature resistance relates to a method for preparing a rigid frame reinforced aerogel ceramic thermal insulation composite material. The present invention aims to solve the technical problems that the existing ceramic fiber insulation tiles have low material utilization, poor thermal stability, and moisture absorption can lead to a decrease in their overall performance. The present invention combines a ceramic frame with aerogel, so that the ceramic frame plays a mechanical support role and the ceramic aerogel is filled inside to play a high-temperature thermal insulation role. In this process, the size of the thermal insulation composite material is controlled by the ceramic frame, avoiding the material utilization problem caused by secondary processing. The process of the present invention is simple, and the dimensional accuracy of the prepared thermal insulation composite material is high. A lightweight rigid frame reinforced aerogel ceramic thermal insulation composite material with high strength, super hydrophobicity and high temperature resistance is successfully prepared.

Description

Technical Field

[0001] The invention relates to a method for preparing a rigid frame reinforced aerogel ceramic thermal insulation composite material. Background Art

[0002] Rigid ceramic fiber thermal insulation composites play a crucial role in thermally protecting large areas of reusable aircraft surfaces in medium- and high-temperature zones. They serve as a safety barrier against high-temperature, high-speed aerodynamic heat fluxes during flight. However, traditional rigid ceramic fiber thermal insulation tiles are heavy, complex to assemble, inspect, maintain, and replace, and have low material utilization, poor thermal stability, and complex assembly. Aerogels also have poor mechanical properties, and moisture absorption can degrade their overall performance, limiting their further application. Summary of the Invention

[0003] The present invention aims to solve the technical problems of low material utilization, poor thermal stability, complex assembly, poor mechanical properties of aerogel, and moisture absorption leading to a decline in its overall performance of existing ceramic fiber insulation tiles, and to provide a method for preparing a lightweight rigid frame reinforced aerogel ceramic insulation composite material with high strength, super hydrophobicity and high temperature resistance.

[0004] The preparation method of the lightweight rigid frame reinforced aerogel ceramic thermal insulation composite material with high strength, super hydrophobicity and high temperature resistance of the present invention is carried out according to the following steps:

[0005] 1. Preparation of the framework:

[0006] ①. Configuration of printing slurry:

[0007] The first batch of ceramic precursor PDMS, crosslinking agent hydrogenated silicone oil and inhibitor 1-ethynyl-1-cyclohexanol are mixed and stirred for 5 minutes to 10 minutes; then the second batch of ceramic precursor PDMS and platinum catalyst are added and stirred for another 5 minutes to 10 minutes; then alumina fiber is added and stirred for 10 minutes to 15 minutes, after which boron nitride powder is added and stirred for 5 minutes to 10 minutes, after which white carbon black and SiO2 spherical particles are added. The white carbon black is added in two equal portions, with the same amount added each time. After the first addition, the mixture is stirred for 10 minutes to 15 minutes, and after the second addition, the mixture is stirred for 30 minutes to 35 minutes.

[0008] The mass ratio of the cross-linking agent hydrogenated silicone oil to the first batch of ceramic precursor PDMS is 1:(15-17);

[0009] The mass ratio of the inhibitor 1-ethynyl-1-cyclohexanol to the first batch of ceramic precursor PDMS is 1:(290-295);

[0010] The mass ratio of the platinum catalyst to the first batch of ceramic precursor PDMS is 1:(500-510);

[0011] The first batch of PDMS ceramic precursor and the second batch of PDMS ceramic precursor have the same quality;

[0012] The mass ratio of the alumina fiber to the first batch of ceramic precursor PDMS is 1:(1-3);

[0013] The mass ratio of the boron nitride powder to the first batch of ceramic precursor PDMS is 1:(7-8);

[0014] The mass ratio of the total mass of silica added twice to the mass ratio of the first batch of ceramic precursor PDMS is 1:(2-5);

[0015] The total mass of white carbon black added twice is the same as the mass of SiO2 spherical particles;

[0016] ②. Printing ceramic frame embryo:

[0017] (1) Using Cinema 4D software to draw a 3D printing model and exporting the model to an STL file, the exported STL file is imported into Cura slicing software for slicing, that is, the drawn 3D model is divided into multiple layers of 2D planes;

[0018] (2) Setting the corresponding printing parameters on the Cura slicing software according to actual needs, and then printing to obtain the ceramic frame embryo; the filling pattern is serrated;

[0019] ③. Print frame curing and heat treatment:

[0020] The printed ceramic frame is placed in an oven for curing, and the cured ceramic frame is heat treated in the following two steps: the curing temperature is 130℃~135℃, and the curing time is 1h~1.5h;

[0021] (1) Pre-oxidation at low temperature: Place the cured ceramic frame in a muffle furnace, heat it from room temperature to 320°C to 330°C and keep it there for 6h to 6.5h at a heating rate of 1°C / min to 2°C / min, and then cool it to room temperature with the furnace;

[0022] (2) heating the pre-oxidized ceramic frame from room temperature to 1100°C to 1300°C and keeping the temperature for 2h to 3h at a heating rate of 2°C / min to 3°C / min, and cooling the furnace to room temperature to obtain a 3D printed ceramic frame;

[0023] 2. Preparation of aerogel slurry: Aluminum sec-butoxide and deionized water were mixed according to the molar ratio of aluminum sec-butoxide to H2O of 1:(60-65), and the mixture was stirred in a water bath at 90℃-95℃ for 1h-1.5h. At this time, the mixed solution was turbid milky white. Nitric acid solution was slowly added thereto to adjust the pH until the mixed solution changed from milky white to clear and transparent. The addition of nitric acid solution was stopped and the mixture was stirred for 9h-9.5h to obtain Al2O3 hydrosol; and then the mixture was allowed to stand at room temperature for 2-3 days to age. The viscosity is increased, and then the aluminum concentration is evaporated in an oil bath at 105°C to 110°C to 1 mol / L. Hydroxyethyl cellulose accounting for 2 wt.% to 3 wt.% of the mass of the Al2O3 hydrosol is added and mixed. The mixture is stirred in a constant temperature water bath at 50°C to 55°C for 2 hours to 2.5 hours to obtain an alumina sol. The RF solution and alumina fibers accounting for 10 wt.% to 11 wt.% of the mass of the Al2O3 hydrosol are then added, stirred evenly, and cooled to room temperature to obtain a ceramic aerogel mixed slurry.

[0024] The RF solution is prepared by mixing resorcinol: formaldehyde: sodium carbonate aqueous solution and water in a mass ratio of (33-35): (43-45): (1.8-2) and (21-22), wherein the concentration of the sodium carbonate aqueous solution is 0.3 mol / L-0.4 mol / L;

[0025] The mass ratio of the alumina sol to the RF solution is (9-5):(1-5);

[0026] 3. Preparation of thermal insulation composite materials:

[0027] Place the 3D printed ceramic frame prepared in step one into a funnel, pour the ceramic aerogel mixed slurry prepared in step two into the funnel, and then fill the aerogel slurry into the 3D printed ceramic frame by vacuum impregnation, and then freeze-dry to obtain a frame-reinforced aerogel ceramic thermal insulation composite material embryo. Subsequently, the embryo is placed in a tubular furnace for heat treatment under argon protection. The treatment method is to increase the temperature to 1300°C~1400°C at 5°C / min~6°C / min and keep it warm for 2h~2.5h to obtain a lightweight rigid frame-reinforced aerogel ceramic thermal insulation composite material with high strength, superhydrophobicity and high temperature resistance.

[0028] In the present invention, RF is introduced to carbonize it at high temperature in step three and cover the surface of aerogel particles and alumina fibers to form a carbon layer packaging structure. The carbon layer acts as a strong cross-linking agent to convert the overlapping points between fibers into strong contacts, so that the fibers form a strong skeleton structure from molecular to micron scale, thereby enhancing their mechanical properties. The carbon layer can also effectively inhibit the phase change of alumina and avoid sintering between fibers, so that it can maintain a complete three-dimensional porous structure at high temperatures. At the same time, the carbon layer can effectively reduce its high-temperature radiation thermal conductivity, thereby enhancing its high-temperature stability and thermal insulation capacity. Since the fibers form a porous skeleton, the rough layered morphology formed by the carbon layer, the rough microstructure and low surface energy carbon, and the point contact between water and fibers form open pores, which give it low surface adhesion, thereby giving it superhydrophobic properties, avoiding the problem of performance degradation of the thermal insulation composite material due to moisture absorption during use.

[0029] In the present invention, spherical silica particles are added in step 1 to prepare a ceramic frame. Since the diameter of the silica particles is different from that of the white carbon black particles, during the mixing process, the small-sized particles can be filled into the gaps between the large particles, thereby increasing the gradation between particles of different particle sizes within the slurry, improving the content of solid phase components in the slurry, and being beneficial to the rheological uniformity of the slurry during extrusion, increasing the density of the monofilaments, and reducing the number of holes formed inside the frame during the sintering process, thereby enhancing its mechanical properties.

[0030] This invention combines a 3D-printed ceramic frame with aerogel fabrication. The 3D ceramic frame provides mechanical support, while the ceramic aerogel filler provides high-temperature insulation. This composite material boasts ultra-high thermal stability (exceeding 1500°C in air), resulting in a lightweight, high-strength, integrated frame-reinforced aerogel-ceramic thermal insulation composite. The ceramic frame controls the size of the thermal insulation composite, eliminating material utilization issues associated with secondary processing.

[0031] The process of the present invention is simple, the size accuracy of the prepared thermal insulation composite material is high, and a lightweight rigid frame reinforced aerogel ceramic thermal insulation composite material with high strength, super hydrophobicity and high temperature resistance is successfully prepared. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A physical picture of the thermal insulation composite material sample prepared for Test 1;

[0033] Figure 2 This is a contact angle test diagram of a thermal insulation composite material prepared in an experiment;

[0034] Figure 3 These are photos of the thermal insulation composite material produced in Experiment 1 after water droplets were added to different parts of its surface.

[0035] Figure 4This is a diagram showing the thermal evaluation results of a thermal insulation composite material produced in a test;

[0036] Figure 5 This is the macroscopic picture of the sample after the above thermal evaluation;

[0037] Figure 6 This is a diagram showing the mechanical test results of the thermal insulation composite material prepared in Experiment 1. DETAILED DESCRIPTION

[0038] Specific embodiment 1: This embodiment is a method for preparing a lightweight rigid frame reinforced aerogel ceramic thermal insulation composite material with high strength, super hydrophobicity and high temperature resistance, which is specifically carried out in the following steps:

[0039] 1. Preparation of the framework:

[0040] ①. Configuration of printing slurry:

[0041] The first batch of ceramic precursor PDMS, crosslinking agent hydrogenated silicone oil and inhibitor 1-ethynyl-1-cyclohexanol are mixed and stirred for 5 minutes to 10 minutes; then the second batch of ceramic precursor PDMS and platinum catalyst are added and stirred for another 5 minutes to 10 minutes; then alumina fiber is added and stirred for 10 minutes to 15 minutes, after which boron nitride powder is added and stirred for 5 minutes to 10 minutes, after which white carbon black and SiO2 spherical particles are added. The white carbon black is added in two equal portions, with the same amount added each time. After the first addition, the mixture is stirred for 10 minutes to 15 minutes, and after the second addition, the mixture is stirred for 30 minutes to 35 minutes.

[0042] The mass ratio of the cross-linking agent hydrogenated silicone oil to the first batch of ceramic precursor PDMS is 1:(15-17);

[0043] The mass ratio of the inhibitor 1-ethynyl-1-cyclohexanol to the first batch of ceramic precursor PDMS is 1:(290-295);

[0044] The mass ratio of the platinum catalyst to the first batch of ceramic precursor PDMS is 1:(500-510);

[0045] The first batch of PDMS ceramic precursor and the second batch of PDMS ceramic precursor have the same quality;

[0046] The mass ratio of the alumina fiber to the first batch of ceramic precursor PDMS is 1:(1-3);

[0047] The mass ratio of the boron nitride powder to the first batch of ceramic precursor PDMS is 1:(7-8);

[0048] The mass ratio of the total mass of silica added twice to the mass ratio of the first batch of ceramic precursor PDMS is 1:(2-5);

[0049] The total mass of white carbon black added twice is the same as the mass of SiO2 spherical particles;

[0050] ②. Printing ceramic frame embryo:

[0051] (1) Using Cinema 4D software to draw a 3D printing model and exporting the model to an STL file, the exported STL file is imported into Cura slicing software for slicing, that is, the drawn 3D model is divided into multiple layers of 2D planes;

[0052] (2) Setting the corresponding printing parameters on the Cura slicing software according to actual needs, and then printing to obtain the ceramic frame embryo; the filling pattern is serrated;

[0053] ③. Print frame curing and heat treatment:

[0054] The printed ceramic frame is placed in an oven for curing, and the cured ceramic frame is heat treated in the following two steps: the curing temperature is 130℃~135℃, and the curing time is 1h~1.5h;

[0055] (1) Pre-oxidation at low temperature: Place the cured ceramic frame in a muffle furnace, heat it from room temperature to 320°C to 330°C and keep it there for 6h to 6.5h at a heating rate of 1°C / min to 2°C / min, and then cool it to room temperature with the furnace;

[0056] (2) heating the pre-oxidized ceramic frame from room temperature to 1100°C to 1300°C and keeping the temperature for 2h to 3h at a heating rate of 2°C / min to 3°C / min, and cooling the furnace to room temperature to obtain a 3D printed ceramic frame;

[0057] 2. Preparation of aerogel slurry: Aluminum sec-butoxide and deionized water were mixed according to the molar ratio of aluminum sec-butoxide to H2O of 1:(60-65), and the mixture was stirred in a water bath at 90℃-95℃ for 1h-1.5h. At this time, the mixed solution was turbid milky white. Nitric acid solution was slowly added thereto to adjust the pH until the mixed solution changed from milky white to clear and transparent. The addition of nitric acid solution was stopped and the mixture was stirred for 9h-9.5h to obtain Al2O3 hydrosol; and then the mixture was allowed to stand at room temperature for 2-3 days to age. The viscosity is increased, and then the aluminum concentration is evaporated in an oil bath at 105°C to 110°C to 1 mol / L. Hydroxyethyl cellulose accounting for 2 wt.% to 3 wt.% of the mass of the Al2O3 hydrosol is added and mixed. The mixture is stirred in a constant temperature water bath at 50°C to 55°C for 2 hours to 2.5 hours to obtain an alumina sol. The RF solution and alumina fibers accounting for 10 wt.% to 11 wt.% of the mass of the Al2O3 hydrosol are then added, stirred evenly, and cooled to room temperature to obtain a ceramic aerogel mixed slurry.

[0058] The RF solution is prepared by mixing resorcinol: formaldehyde: sodium carbonate aqueous solution and water in a mass ratio of (33-35): (43-45): (1.8-2) and (21-22), wherein the concentration of the sodium carbonate aqueous solution is 0.3 mol / L-0.4 mol / L;

[0059] The mass ratio of the alumina sol to the RF solution is (9-5):(1-5);

[0060] 3. Preparation of thermal insulation composite materials:

[0061] Place the 3D printed ceramic frame prepared in step one into a funnel, pour the ceramic aerogel mixed slurry prepared in step two into the funnel, and then fill the aerogel slurry into the 3D printed ceramic frame by vacuum impregnation, and then freeze-dry to obtain a frame-reinforced aerogel ceramic thermal insulation composite material embryo. Subsequently, the embryo is placed in a tubular furnace for heat treatment under argon protection. The treatment method is to heat the frame at 5°C / min~6°C / min to 1300°C~1400°C and keep it warm for 2h~2.5h to obtain a lightweight rigid frame-reinforced aerogel ceramic thermal insulation composite material with high strength, superhydrophobicity and high temperature resistance.

[0062] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that the printing parameters in step ②(2) of step 1 are: a needle diameter of 0.84 mm, a printed layer spacing of 70% of the needle diameter, a printing speed of 20 mm / s, a frame fill rate of 43%, a printed blank size of 40 mm × 40 mm × 15 mm, and a layer angle of 90°. Other parameters are the same as those in specific embodiment 1.

[0063] Specific embodiment 3: This embodiment differs from specific embodiment 1 or 2 in that the curing temperature in step 1 ③ is 130°C to 135°C and the curing time is 1 hour to 1.5 hours. Other aspects are the same as specific embodiment 1 or 2.

[0064] Specific embodiment 4: This embodiment differs from Specific embodiments 1 to 3 in that in step 1, step 3 (1), pre-oxidation is performed at a low temperature: the cured ceramic frame is placed in a muffle furnace, heated from room temperature to 320°C and maintained at this temperature for 6 hours at a heating rate of 1°C / min, and then cooled to room temperature in the furnace. Other aspects are the same as Specific embodiments 1 to 3.

[0065] Specific embodiment 5: This embodiment differs from specific embodiment 4 in that in step 1 ③ (2), the pre-oxidized ceramic frame is heated from room temperature to 1300°C and held at this temperature for 2 hours at a heating rate of 2°C / min, and then cooled to room temperature in the furnace to obtain a 3D printed ceramic frame. Other aspects are the same as specific embodiment 4.

[0066] Specific Embodiment 6: This embodiment differs from Specific Embodiment 5 in that the RF solution in step 2 is prepared by mixing resorcinol: formaldehyde: sodium carbonate aqueous solution and water in a mass ratio of 33.43:43:1.82 and 21.75, respectively, with the concentration of the sodium carbonate aqueous solution being 0.3 mol / L. Other aspects are the same as Specific Embodiment 5.

[0067] Specific embodiment 7: This embodiment differs from specific embodiment 6 in that the mass ratio of the alumina sol to the RF solution in step 2 is 7:3. Other aspects are the same as specific embodiment 6.

[0068] Specific embodiment eight: This embodiment differs from specific embodiment seven in that in step three, the temperature is raised to 1300° C. at 5° C. / min and kept at that temperature for 2 hours. Other aspects are the same as specific embodiment seven.

[0069] Specific embodiment 9: This embodiment differs from specific embodiment 8 in that the vacuum degree during vacuum impregnation in step 3 is 0.06 MPa to 0.065 MPa. Other aspects are the same as specific embodiment 8.

[0070] Specific embodiment 10: This embodiment differs from specific embodiment 9 in that the freeze drying in step 3 is performed at a temperature of -50°C to -55°C until the product is completely frozen. Other aspects are the same as specific embodiment 9.

[0071] The present invention is verified by the following test:

[0072] Experiment 1: This experiment is a preparation method for a lightweight rigid frame reinforced aerogel ceramic thermal insulation composite material with high strength, super hydrophobicity and high temperature resistance. The specific steps are as follows:

[0073] 1. Preparation of the framework:

[0074] ①. Configuration of printing slurry:

[0075] 50g of ceramic precursor PDMS, 3g of cross-linking agent hydrogenated silicone oil and 0.17g of inhibitor 1-ethynyl-1-cyclohexanol were mixed and stirred for 5 minutes; then 50g of ceramic precursor PDMS and 0.1g of platinum catalyst were added and stirred for another 5 minutes; 20g of alumina fiber was added and stirred for 10 minutes, followed by 7g of boron nitride powder and stirring for 5 minutes, followed by 25g of white carbon black and 25g of SiO2 spherical particles. The white carbon black was added in two equal additions, with the same amount added each time. Stirring was performed for 10 minutes after the first addition and for 30 minutes after the second addition.

[0076] ②. Printing ceramic frame embryo:

[0077] (1) Using Cinema 4D software to draw a 3D printing model and exporting the model to an STL file, the exported STL file is imported into Cura slicing software for slicing, that is, the drawn 3D model is divided into multiple layers of 2D planes;

[0078] (2) According to actual needs, the corresponding printing parameters are set on the Cura slicing software, and then printing is performed to obtain a ceramic frame embryo; the printing parameters are: the needle diameter is 0.84 mm, the printing layer spacing is 0.6 mm, the printing speed is 20 mm / s, the frame filling rate is 43%, the printing pressure is 0.6 MPa, the filling pattern is serrated, and the interlayer angle is 90°; then printing is performed, the needle extrudes the monofilament along the preset printing path, and after printing one layer, the printing platform is lowered along the Z axis by a layer height distance. The monofilament printed in the second layer is rotated 90° on the basis of the monofilament printed in the first layer to form a lap unit between the monofilaments. The entire ceramic frame embryo can be obtained by repeated printing. The size of the printed embryo is 40 mm × 40 mm × 10 mm in length;

[0079] ③. Print frame curing and heat treatment:

[0080] The printed ceramic frame was placed in an oven for curing, and the cured ceramic frame was heat treated in the following two steps: the curing temperature was 130°C and the time was 1h;

[0081] (1) Pre-oxidation at low temperature: Place the cured ceramic frame in a muffle furnace, heat it from room temperature to 320°C and keep it there for 6 hours at a heating rate of 1°C / min, and then cool it to room temperature in the furnace;

[0082] (2) The pre-oxidized ceramic frame is heated from room temperature to 1300°C and kept at this temperature for 2 h at a heating rate of 2°C / min, and then cooled to room temperature in the furnace to obtain a 3D printed ceramic frame;

[0083] 2. Configuration of aerogel slurry: Aluminum sec-butoxide and deionized water are mixed according to a molar ratio of aluminum sec-butoxide to H2O of 1:60, and the mixture is stirred in a water bath at 90°C for 1 hour. At this time, the mixed solution is turbid milky white, and nitric acid solution is slowly added thereto to adjust the pH until the mixed solution changes from milky white to clear transparent color. Stop adding nitric acid solution, and continue stirring for 9 hours to obtain Al2O3 hydrosol; then stand at room temperature for 2 days to age it to increase the viscosity, and then evaporate it in an oil bath at 105°C to a concentration of aluminum element of 1 mol / L, add hydroxyethyl cellulose accounting for 2 wt.% of the mass of Al2O3 hydrosol, and stir in a constant temperature water bath at 50°C for 2 hours to obtain alumina sol; then add RF solution and alumina fiber accounting for 10 wt.% of the mass of Al2O3 hydrosol, stir evenly, and cool to room temperature to obtain ceramic aerogel mixed slurry;

[0084] The RF solution is prepared by mixing resorcinol: formaldehyde: sodium carbonate aqueous solution and water in a mass ratio of 33.43:43:1.82 and 21.75, wherein the concentration of the sodium carbonate aqueous solution is 0.3 mol / L;

[0085] The mass ratio of the alumina sol to the RF solution is 7:3;

[0086] 3. Preparation of thermal insulation composite materials:

[0087] The 3D printed ceramic frame prepared in step 1 is placed in a funnel, and the ceramic aerogel mixed slurry prepared in step 2 is poured into the funnel. The aerogel slurry is then filled into the 3D printed ceramic frame by vacuum impregnation, and then freeze-dried to obtain a frame-reinforced aerogel ceramic thermal insulation composite material embryo. The embryo is then placed in a tubular furnace for heat treatment under argon protection. The treatment method is to increase the temperature at 5°C / min to 1300°C and keep it for 2 hours to obtain a lightweight rigid frame-reinforced aerogel ceramic thermal insulation composite material with high strength, superhydrophobicity and high temperature resistance;

[0088] The vacuum degree during vacuum impregnation in step 3 is 0.06 MPa;

[0089] The freeze drying in step 3 is to freeze at a temperature of -50°C until the product is completely frozen.

[0090] Figure 1 This is a real picture of the thermal insulation composite material sample prepared in the experiment. It can be seen from the picture that the surface morphology of the sample is good.

[0091] Figure 2 This is a contact angle test diagram of a thermal insulation composite material prepared in an experiment. It can be seen from the figure that the hydrophobic angle of the prepared sample is 145°.

[0092] At the same time, water drops were added to different parts of the sample surface, such as Figure 3 As shown, it can be seen that the water droplets are spherical on the surface of the sample, and their shape is well maintained, indicating that the samples prepared in this experiment have good hydrophobic properties.

[0093] Figure 4 This is a thermal evaluation result diagram of a thermal insulation composite material prepared in an experiment. The sample thickness is 10mm. It can be seen from the figure that when the front of the sample is subjected to a temperature of 1300℃, the temperature of its back begins to stabilize at around 220℃ after 150s. The temperature difference between the front and back of the sample reaches 1080℃, indicating that its thermal insulation performance is excellent.

[0094] Figure 5 This is the macroscopic picture of the sample after the above thermal evaluation. It can be seen from the figure that after 10 minutes, under 1300℃ flame impact, its surface is different from the sample picture before thermal evaluation ( Figure 1), indicating that the samples prepared in this experiment have good high-temperature stability and temperature resistance.

[0095] Figure 6 This is the mechanical test result of the thermal insulation composite material prepared in Experiment 1. As can be seen from the figure, the compressive strength of the sample prepared in this experiment is 0.9 MPa, indicating that the room temperature mechanical properties of the sample prepared in this experiment are relatively high.

[0096] The thermal insulation composite material prepared in Experiment 1 was subjected to a 1500°C temperature resistance test, with each test lasting half an hour and repeated 5 times. The results are shown in Table 1. The results in the table show that the ceramic thermal insulation composite material prepared in this experiment has good temperature resistance. After the test at 1500°C, the mass and size only undergo negligible slight changes.

[0097] Table 1 Temperature resistance test results (1500℃, half an hour)

[0098]

[0099]

Claims

1. A method for preparing a lightweight rigid frame reinforced aerogel ceramic thermal insulation composite material with high strength, super hydrophobicity and high temperature resistance, characterized in that The preparation method of a lightweight rigid frame reinforced aerogel ceramic thermal insulation composite material with high strength, super hydrophobicity and high temperature resistance is carried out according to the following steps:

1. Preparation of the framework: ①. Configuration of printing slurry: The first batch of ceramic precursor PDMS, crosslinking agent hydrogenated silicone oil and inhibitor 1-ethynyl-1-cyclohexanol are mixed and stirred for 5 minutes to 10 minutes; then the second batch of ceramic precursor PDMS and platinum catalyst are added and stirred for another 5 minutes to 10 minutes; then alumina fiber is added and stirred for 10 minutes to 15 minutes, after which boron nitride powder is added and stirred for 5 minutes to 10 minutes, after which white carbon black and SiO2 spherical particles are added. The white carbon black is added in two equal portions, with the same amount added each time. After the first addition, the mixture is stirred for 10 minutes to 15 minutes, and after the second addition, the mixture is stirred for 30 minutes to 35 minutes. The mass ratio of the cross-linking agent hydrogenated silicone oil to the first batch of ceramic precursor PDMS is 1:(15-17); The mass ratio of the inhibitor 1-ethynyl-1-cyclohexanol to the first batch of ceramic precursor PDMS is 1:(290-295); The mass ratio of the platinum catalyst to the first batch of ceramic precursor PDMS is 1:(500-510); The first batch of PDMS ceramic precursor and the second batch of PDMS ceramic precursor have the same quality; The mass ratio of the alumina fiber to the first batch of ceramic precursor PDMS is 1:(1-3); The mass ratio of the boron nitride powder to the first batch of ceramic precursor PDMS is 1:(7-8); The mass ratio of the total mass of silica added twice to the mass ratio of the first batch of ceramic precursor PDMS is 1:(2-5); The total mass of white carbon black added twice is the same as the mass of SiO2 spherical particles; ②. Printing ceramic frame embryo: (1) Using Cinema 4D software to draw a 3D printing model and exporting the model to an STL file, the exported STL file is imported into Cura slicing software for slicing, that is, the drawn 3D model is divided into multiple layers of 2D planes; (2) Setting the corresponding printing parameters on the Cura slicing software according to actual needs, and then printing to obtain the ceramic frame embryo; the filling pattern is serrated; ③. Print frame curing and heat treatment: Place the printed ceramic frame in an oven for curing at a temperature of 130°C to 135°C for 1 hour to 1.5 hours. Heat treat the cured ceramic frame in the following two steps: (1) Pre-oxidation at low temperature: Place the cured ceramic frame in a muffle furnace, heat it from room temperature to 320°C to 330°C and keep it there for 6h to 6.5h at a heating rate of 1°C / min to 2°C / min, and then cool it to room temperature with the furnace; (2) heating the pre-oxidized ceramic frame from room temperature to 1100°C to 1300°C and keeping the temperature for 2h to 3h at a heating rate of 2°C / min to 3°C / min, and cooling the furnace to room temperature to obtain a 3D printed ceramic frame; 2. Preparation of aerogel slurry: Aluminum sec-butoxide and deionized water were mixed according to the molar ratio of aluminum sec-butoxide to H2O of 1:(60-65), and the mixture was stirred in a water bath at 90℃-95℃ for 1h-1.5h. At this time, the mixed solution was turbid milky white. Nitric acid solution was slowly added thereto to adjust the pH until the mixed solution changed from milky white to clear and transparent. The addition of nitric acid solution was stopped and the stirring was continued for 9h-9.5h to obtain Al2O3 hydrosol; and then the mixture was allowed to stand at room temperature for 2-3 days to age. The viscosity is increased, and then the aluminum concentration is evaporated in an oil bath at 105°C to 110°C to 1 mol / L. Hydroxyethyl cellulose accounting for 2 wt.% to 3 wt.% of the mass of the Al2O3 hydrosol is added and mixed. The mixture is stirred in a constant temperature water bath at 50°C to 55°C for 2 hours to 2.5 hours to obtain an alumina sol. The RF solution and alumina fibers accounting for 10 wt.% to 11 wt.% of the mass of the Al2O3 hydrosol are then added, stirred evenly, and cooled to room temperature to obtain a ceramic aerogel mixed slurry. The RF solution is prepared by mixing resorcinol: formaldehyde: sodium carbonate aqueous solution and water in a mass ratio of (33-35): (43-45): (1.8-2) and (21-22), wherein the concentration of the sodium carbonate aqueous solution is 0.3 mol / L-0.4 mol / L; The mass ratio of the alumina sol to the RF solution is (9-5):(1-5); 3. Preparation of thermal insulation composite materials: Place the 3D printed ceramic frame prepared in step one into a funnel, pour the ceramic aerogel mixed slurry prepared in step two into the funnel, and then fill the aerogel slurry into the 3D printed ceramic frame by vacuum impregnation, and then freeze-dry to obtain a frame-reinforced aerogel ceramic thermal insulation composite material embryo. Subsequently, the embryo is placed in a tubular furnace for heat treatment under argon protection. The treatment method is to heat the frame at 5°C / min~6°C / min to 1300°C~1400°C and keep it warm for 2h~2.5h to obtain a lightweight rigid frame-reinforced aerogel ceramic thermal insulation composite material with high strength, superhydrophobicity and high temperature resistance.

2. The method for preparing a lightweight rigid frame reinforced aerogel ceramic thermal insulation composite material with high strength, super hydrophobicity and high temperature resistance according to claim 1, characterized in that The printing parameters in step 1 (2) are as follows: the needle diameter is 0.84 mm, the printed layer spacing is 70% of the needle diameter, the printing speed is 20 mm / s, the frame filling rate is 43%, the size of the printed embryo is 40 mm × 40 mm × 15 mm in length, and the layer angle is 90°.

3. The method for preparing a lightweight rigid frame reinforced aerogel ceramic thermal insulation composite material with high strength, super hydrophobicity and high temperature resistance according to claim 1, characterized in that In step 1③(1), pre-oxidation is performed at low temperature: the cured ceramic frame is placed in a muffle furnace, heated from room temperature to 320°C and kept at this temperature for 6 hours at a heating rate of 1°C / min, and then cooled to room temperature in the furnace.

4. The method for preparing a lightweight rigid frame reinforced aerogel ceramic thermal insulation composite material with high strength, super hydrophobicity and high temperature resistance according to claim 1, characterized in that In step 1③(2), the pre-oxidized ceramic frame is heated from room temperature to 1300°C and kept warm for 2 hours at a heating rate of 2°C / min. It is then cooled to room temperature in the furnace to obtain a 3D printed ceramic frame.

5. The method for preparing a lightweight rigid frame reinforced aerogel ceramic thermal insulation composite material with high strength, super hydrophobicity and high temperature resistance according to claim 1, characterized in that The RF solution described in step 2 is prepared by mixing resorcinol: formaldehyde: sodium carbonate aqueous solution and water in a mass ratio of 33.43:43:1.82 and 21.75, wherein the concentration of the sodium carbonate aqueous solution is 0.3 mol / L.

6. The method for preparing a lightweight rigid frame reinforced aerogel ceramic thermal insulation composite material with high strength, super hydrophobicity and high temperature resistance according to claim 1, characterized in that The mass ratio of the alumina sol to the RF solution in step 2 is 7:

3.

7. The method for preparing a lightweight rigid frame reinforced aerogel ceramic thermal insulation composite material with high strength, super hydrophobicity and high temperature resistance according to claim 1, characterized in that In step 3, the temperature was raised to 1300°C at 5°C / min and kept at this temperature for 2h.

8. The method for preparing a lightweight rigid frame reinforced aerogel ceramic thermal insulation composite material with high strength, super hydrophobicity and high temperature resistance according to claim 1, characterized in that The vacuum degree during vacuum impregnation in step 3 is 0.06 MPa to 0.065 MPa.

9. The method for preparing a lightweight rigid frame reinforced aerogel ceramic thermal insulation composite material with high strength, super hydrophobicity and high temperature resistance according to claim 1, characterized in that The freeze drying described in step 3 is to freeze at a temperature of -50°C to -55°C until the product is completely frozen.

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