High-performance ceramic matrix composite material for unmanned aerial vehicle and preparation method and application thereof

Abstract

The application relates to the technical field of high polymer materials, and discloses a high-performance ceramic matrix composite material for an unmanned aerial vehicle and a preparation method and application thereof. The preparation method of the high-performance ceramic matrix composite material for the unmanned aerial vehicle comprises the following steps: preparing a bonding layer on a silicon carbide fiber reinforced silicon carbide ceramic matrix; preparing a heat-insulating water-resistant layer on the bonding layer; preparing a thermal expansion buffer layer on the heat-insulating water-resistant layer; preparing an oxygen barrier layer on the thermal expansion buffer layer; modifying the oxygen barrier layer by using polydopamine; and then preparing an aerogel coating layer on the polydopamine-modified oxygen barrier layer by using a gasless spraying technology, so as to obtain the high-performance ceramic matrix composite material for the unmanned aerial vehicle. The high-performance ceramic matrix composite material for the unmanned aerial vehicle has excellent high-temperature resistance, oxidation resistance, heat insulation and water vapor corrosion resistance, and can be used in unmanned aerial vehicle body and wing materials.

Description

Technical Field

[0001] This invention relates to the field of silicon carbide fiber-reinforced silicon carbide ceramic matrix composites, and particularly to a high-performance ceramic matrix composite for unmanned aerial vehicles (UAVs) and its preparation and application. Background Technology

[0002] In the fields of aerospace, drones, and high-end equipment manufacturing, composite materials are widely used in key components such as fuselages and wings due to their lightweight and high strength. The composite materials commonly used in existing technologies include resin-based composite materials or ceramic-based composite materials. Resin-based composite materials have problems such as low melting point, insufficient high-temperature resistance, and susceptibility to corrosion by smoke at fire scenes, leading to failure. Carbon fiber reinforced silicon carbide ceramic matrix composite materials and silicon carbide fiber reinforced silicon carbide ceramic matrix composite materials are two commonly used ceramic matrix composite materials. However, under high-temperature aerobic conditions, the increased oxidation of silicon carbide will lead to a significant decrease in the mechanical properties of silicon carbide ceramics and silicon carbide fibers, and may even lead to material failure. In addition, under high-temperature conditions in the presence of water vapor, the oxidation rate of silicon carbide increases significantly, and the damage to the oxide layer is more severe.

[0003] Therefore, improving the high-temperature oxidation resistance and water vapor corrosion resistance of silicon carbide ceramic matrix composites, enabling drones containing silicon carbide fiber-reinforced silicon carbide ceramic matrix composites to be used in high-temperature and water vapor environments, and thus broadening the application scenarios of drones, is of great significance. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a method for preparing high-performance ceramic matrix composite materials for unmanned aerial vehicles (UAVs), comprising the following steps:

[0005] Step 1: Prepare a bonding layer with a thickness of 50-150 μm on a silicon carbide fiber-reinforced silicon carbide ceramic matrix using atmospheric plasma spraying technology;

[0006] Step 2: Prepare a heat-insulating and water-resistant layer with a thickness of 100-200 μm on the adhesive layer of Step 1 using supersonic atmospheric plasma spraying technology;

[0007] Step 3: Prepare a thermal expansion buffer layer with a thickness of 30-50μm on the heat insulation and water-resistant layer in Step 2 using atmospheric plasma spraying technology;

[0008] Step 4: An oxygen barrier layer with a thickness of 30-50 μm is prepared on the thermal expansion buffer layer in Step 3 using atmospheric plasma spraying technology, thereby obtaining a high-performance ceramic substrate;

[0009] Step 5: Modify the oxygen barrier layer from Step 4 with polydopamine, and then prepare an aerogel coating with a thickness of 2-3 mm on the polydopamine-modified oxygen barrier layer using airless spraying technology to obtain a high-performance ceramic matrix composite material for UAVs.

[0010] Preferably, the coefficient of thermal expansion of the silicon carbide fiber-reinforced silicon carbide ceramic matrix is ​​4.5-5.5 × 10⁻⁶. -6 K -1 The coefficient of thermal expansion of the adhesive layer is 5.88-7.04×10⁻⁶. -6 K -1 The coefficient of thermal expansion of the heat-insulating and water-resistant layer is 5.0-8.0×10⁻⁶. -6 K -1 The coefficient of thermal expansion of the thermal expansion buffer layer is 6.0-9.0×10⁻⁶. -6 K -1 The coefficient of thermal expansion of the oxygen barrier layer is 9.0-10.1×10⁻⁶. -6 K -1 .

[0011] Preferably, in step one, the method for preparing the adhesive layer is as follows:

[0012] Tantalum silicide powder and tantalum oxide powder were mixed at a mass ratio of 9:1 to obtain a raw material composite powder. The raw material composite powder, gum arabic, ammonium citrate, and deionized water were mixed at a mass ratio of (41.5-48.2):(1-2):(0.8-1.5):(50-55), ball-milled, spray-granulated, and sieved to obtain a binder layer mixed powder with a particle size of 32-125μm. The grinding balls used in the ball milling process were zirconia grinding balls, the ball-to-material ratio was 1:(1-2), and the ball milling time was 45-55h.

[0013] The silicon carbide fiber-reinforced silicon carbide ceramic matrix is ​​preheated to 500°C using a plasma flame. Then, the above-mentioned binder layer mixed powder is sprayed onto the silicon carbide fiber-reinforced silicon carbide ceramic matrix using atmospheric plasma spraying technology to form a binder layer. The spraying conditions are as follows: spraying power is 42kW, spraying distance is 100mm, argon is used as the protective gas, hydrogen is used as the combustion gas, argon flow rate is 35slpm, hydrogen flow rate is 12slpm, feed rate is 50g / min, spray gun speed is 300mm / s, and spraying time is 2-3min.

[0014] Furthermore, the particle size of the tantalum silicide powder is 3-5 μm; the particle size of the tantalum oxide powder is 5-10 μm.

[0015] In step one above, tantalum silicide possesses high hardness, low density, and excellent thermal stability, with a melting point as high as 2300℃. However, its coefficient of thermal expansion is relatively high, which may cause cracking of the adhesive layer. Therefore, using it in combination with tantalum oxide helps to reduce the coefficient of thermal expansion of the adhesive layer (5.88-7.04×10⁻⁶ in the range of 200-1400℃). -6 K -1 The adhesive layer improves the bonding strength between the substrate and the coating. In addition to tantalum silicide and tantalum oxide components in the raw material powder, the adhesive layer also contains silicon dioxide (generated by the oxidation reaction between some tantalum silicide and the surrounding environment during the spraying process). The adhesive layer has good high temperature resistance and good thermal expansion coefficient matching with the silicon carbide fiber reinforced silicon carbide ceramic matrix. However, the adhesive layer has poor water vapor resistance.

[0016] Preferably, in step two, the method for preparing the heat-insulating and water-resistant layer is as follows:

[0017] Alumina powder, hafnium dioxide powder, and tantalum oxide powder were mixed in a molar ratio of 1:2:1 and ball-milled with ethanol as the medium. The resulting slurry was dried at 55-65℃ for 20-30 hours and then passed through a 120-mesh sieve. The resulting solid particles were reacted at 1550-1650℃ for 11-13 hours to obtain AlHfTaO6 powder. The grinding balls used in the ball milling process were zirconium oxide grinding balls, the ball-to-powder ratio was (3-6):1, and the ball milling time was 6-10 hours.

[0018] The AlHfTaO6 powder was sprayed onto the surface of the adhesive layer using supersonic atmospheric plasma spraying technology to form a heat-insulating and water-resistant layer. The spraying conditions were as follows: spraying power of 50kW, spraying distance of 100mm, argon as the protective gas, hydrogen as the combustion gas, argon flow rate of 68slpm, hydrogen flow rate of 5slpm, feed rate of 25g / min, spray gun speed of 300mm / s, and spraying time of 2-3min.

[0019] Furthermore, the particle size of the alumina powder, hafnium dioxide powder, and tantalum oxide powder is 50-1000 nm.

[0020] In step two above, the AlHfTaO6 powder is sprayed onto the surface of the adhesive layer using supersonic atmospheric plasma spraying technology to form a heat-insulating and water-resistant AlHfTaO6 ceramic coating. This AlHfTaO6 ceramic coating not only has a low thermal conductivity of 1.4-1.8 W / (m·K) from room temperature to 1500℃, but also a suitable coefficient of thermal expansion, which is better than that of the silicon carbide fiber-reinforced silicon carbide ceramic matrix and the adhesive layer. Furthermore, the AlHfTaO6 ceramic coating also exhibits excellent high-temperature resistance and resistance to water vapor corrosion. During water vapor corrosion, the porous HfO2 layer, a product of water vapor corrosion, protects the internal AlHfTaO6 and transforms scouring corrosion into less aggressive diffusion corrosion. Therefore, the AlHfTaO6 ceramic coating can improve the high-temperature resistance, heat insulation, and water vapor resistance of silicon carbide fiber-reinforced silicon carbide ceramic materials.

[0021] Preferably, in step three, the method for preparing the thermal expansion buffer layer is as follows:

[0022] Thulium oxide powder and tantalum oxide powder were mixed in a molar ratio of 1:3 and ball-milled with ethanol as the medium. The resulting slurry was dried at 65-75℃ for 10-14 hours and passed through a 300-mesh sieve. The resulting solid particles were sintered at 1450-1550℃ for 11-13 hours to obtain TmTa3O9 powder. The grinding balls used in the ball milling process were zirconium oxide grinding balls, the ball-to-powder ratio was 1:(1-2), and the ball milling time was 10-14 hours.

[0023] The above-mentioned TmTa3O9 powder was sprayed onto the heat-insulating and water-resistant layer using atmospheric plasma spraying technology to form a thermal expansion buffer layer. The spraying conditions were as follows: spraying power of 46kW, spraying distance of 150mm, argon as protective gas, hydrogen as combustion gas, argon flow rate of 35slpm, hydrogen flow rate of 12slpm, feed rate of 30g / min, spray gun speed of 300mm / s, and spraying time of 1-2min.

[0024] Furthermore, the particle size of the thulium oxide powder is 1-5 μm; the particle size of the tantalum oxide powder is 5-10 μm.

[0025] In step three above, the TmTa3O9 powder is sprayed onto the heat-insulating and water-resistant layer using atmospheric plasma spraying technology to form a thermal expansion buffer layer, the TmTa3O9 ceramic coating. The thermal expansion buffer layer is located between the heat-insulating and water-resistant layer and the oxygen barrier layer, which reduces the difference in thermal expansion coefficients between the two layers, improves the thermal stress caused by the difference in thermal expansion coefficients, prevents coating cracking, and extends the service life of the coating.

[0026] Preferably, in step four, the method for preparing the high-performance ceramic matrix is ​​as follows:

[0027] Yttrium oxide powder, dysprosium oxide powder, samarium oxide powder, erbium oxide powder, ytterbium oxide powder, gadolinium oxide powder, and tantalum oxide powder were mixed in a molar ratio of 1:1:1:1:1:1:6 and ball-milled with ethanol as the medium. The resulting slurry was first rotary evaporated at 75-80℃ for 5-8 min, then dried at 95-100℃ for 6-10 h, and passed through a 300-mesh sieve. The resulting solid particles were calcined at 1250-1350℃ for 4.5-5.5 h to obtain high-entropy powder. The grinding balls used in the ball milling process were zirconia grinding balls, with a ball-to-powder ratio of 1:(1-2), and the ball milling time was 8-10 h.

[0028] The high-entropy powder was sprayed onto a thermal expansion buffer layer using atmospheric plasma spraying technology to form an oxygen barrier layer, thereby obtaining a high-performance ceramic matrix. The spraying conditions were as follows: spraying power of 42kW, spraying distance of 100mm, argon as the protective gas, hydrogen as the combustion gas, argon flow rate of 35slpm, hydrogen flow rate of 12slpm, feed rate of 30g / min, spray gun speed of 300mm / s, and spraying time of 1-2min.

[0029] Furthermore, the particle size of the yttrium oxide powder, dysprosium oxide powder, samarium oxide powder, erbium oxide powder, ytterbium oxide powder, gadolinium oxide powder, and tantalum oxide powder is 5-10 μm.

[0030] In step four above, the high-entropy powder is sprayed onto the thermal expansion buffer layer using atmospheric plasma spraying technology to form an oxygen barrier layer (Y). 1 / 6 Dy 1 / 6 Sm 1 / 6 Er 1 / 6 Yb 1 / 6 Gd 1 / 6 The high-entropy ceramic coating of TaO4, due to the scattering of phonons at multiple frequencies, (Y 1 / 6 Dy 1 / 6 Sm 1 / 6 Er 1 / 6 Yb 1 / 6 Gd 1 / 6 The high-entropy TaO4 ceramic coating exhibits low thermal conductivity below 1200℃, with a thermal conductivity of 0.986-1.017 W / (m·K), which is 14.3-40.5% lower than that of normal single-phase RETaO4 ceramic coatings. Furthermore, the low grain size, high oxygen ion migration enthalpy, and activation energy collectively contribute to (Y 1 / 6 Dy 1 / 6 Sm 1 / 6 Er 1 / 6 Yb 1 / 6 Gd 1 / 6 The low oxygen ion conductivity of the TaO4 high-entropy ceramic coating, (Y 1 / 6 Dy 1 / 6 Sm1 / 6 Er 1 / 6 Yb 1 / 6 Gd 1 / 6 Compared with single-phase RETaO4 ceramic coating, the oxygen ion conductivity of TaO4 high-entropy ceramic coating can be reduced by 2-7 times. Therefore, the oxygen barrier layer of the present invention has excellent high temperature resistance, heat insulation performance and oxygen barrier and anti-oxidation performance.

[0031] Preferably, in step five, the method for preparing the high-performance ceramic matrix composite material for the UAV is as follows:

[0032] At 24-26℃, dopamine hydrochloride, Tris-HCl buffer, and ethanol are mixed at a ratio of (9-10) g:(7500-9000) mL:(2500-3000) mL to obtain a modification solution; the oxygen barrier layer of the high-performance ceramic matrix described in step four is immersed in the modification solution for 20-28 h at 24-26℃, then removed, washed, and dried to obtain a pretreated high-performance ceramic matrix;

[0033] High-performance silica aerogel powder, hollow glass microspheres, ethanol, and defoamer TEGO 901W are mixed uniformly in a mass ratio of (60-75):(8-15):(20-27):(0.3-0.5) to obtain an aerogel coating. The aerogel coating is then sprayed onto a polydopamine-modified oxygen barrier layer using an airless spraying method. The spraying is repeated 2-3 times and then dried to form an aerogel coating, thereby obtaining a high-performance ceramic matrix composite material for UAVs.

[0034] In step five above, the oxygen barrier layer of the high-performance ceramic matrix described in step four is immersed in the modification liquid to form polydopamine on the surface of the oxygen barrier layer. Polydopamine has a good adhesion effect on a variety of materials, and the catechol groups of polydopamine can be bonded to the high-performance silica aerogel through covalent and non-covalent bonds. Even at high temperatures, with the protection of the outer aerogel coating, the polydopamine layer can only be partially carbonized, and the aerogel coating can still maintain a good connection with the inner ceramic material, avoiding cracking or peeling of the aerogel coating.

[0035] Furthermore, in step four, the method for preparing the modified silica aerogel is as follows:

[0036] Step S1: At 24-26℃, deionized water, ethanol, and hydrochloric acid aqueous solution are mixed, and then phenyltrimethoxysilane, ethyl silicate, and methyltrimethoxysilane are added. The mixture is stirred for 6-8 hours to obtain a mixed solution. The mixed solution is added to an ammonia aqueous solution and stirred for 44-52 hours. The mixture is centrifuged, washed, and dried. The dried product is pyrolyzed at 950-1050℃ for 100-150 minutes to obtain SiOC nanospheres. The volume ratio of deionized water, ethanol, hydrochloric acid aqueous solution, phenyltrimethoxysilane, ethyl silicate, methyltrimethoxysilane, and ammonia aqueous solution is (150-300):(300-600):(0.04-0.08):(80-160):(19-38):(11-22):(1400-2800).

[0037] Step S2: SiOC nanospheres, deionized water, ethanol, and 25wt% ammonia solution are mixed and heated to 74-76℃ to obtain mixture A; ethyl silicate and methyltriethoxysilane are mixed at a molar ratio of 1:(1.2-1.4) and heated to 74-76℃ to obtain mixture B; mixture A and mixture B are mixed and stirred for 22-26 hours, concentrated under vacuum, and replaced with ethanol as the solvent to obtain 18-20wt% monodisperse modified silica sol; wherein, in the mixed system composed of mixture A and mixture B, the concentration of ethyl silicate is 0.18mol / L, the mass ratio of deionized water to ethyl silicate is 126.8:1, the concentration of ammonia is 0.1-0.15mol / L, and the amount of SiOC nanospheres is 9-12% of the total mass of ethyl silicate and methyltriethoxysilane;

[0038] Monodisperse modified silica sol was gelled in a water bath at 48-52℃. After gelation, the sample was aged at 48-52℃ for 2 days and dried. The dried sample was then heated in air at 490-510℃ for 1.5-2.5 hours, pulverized, and ground to obtain high-performance silica aerogel powder with a particle size of 10-20μm.

[0039] In the above process, unlike the traditional two-step acid-base method, the silica aerogel prepared by the method of this invention has a lower thermal conductivity, and the silica aerogel prepared by monodisperse silica sol has a large particle size and narrow particle size distribution. This unique structure can effectively reduce the sintering driving force and inhibit the viscous flow between aerogel particles, thereby improving the high-temperature resistance of silica aerogel. Furthermore, adding reinforcing fillers is a common way to improve the performance of aerogel materials, but many reinforcing materials have poor compatibility with the aerogel matrix. If the reinforcing material is incompatible with the matrix, this usually leads to agglomeration and phase separation of the reinforcing material. Therefore, this invention prepares a SiOC nanosphere with good compatibility with silica aerogel. The SiOC nanospheres encapsulated in the aerogel matrix retain their spherical morphology under high-temperature conditions, effectively... The addition of SiOC nanospheres enhances the stability of the framework structure. Furthermore, the formation of unique island-like structures within the aerogel after the addition of SiOC nanospheres reduces the pore size between the framework particles. This reduced pore size helps restrict air transport within the framework, thereby decreasing gas-phase heat transfer. Simultaneously, the density of the aerogel composite material decreases after the addition of SiOC nanospheres, indicating a weakening effect on solid-phase heat transfer. Therefore, the addition of SiOC nanospheres simultaneously reduces both gas-phase and solid-phase heat transfer, leading to a decrease in the thermal conductivity of the aerogel and an improvement in its insulation performance. In addition, this invention prepares silica aerogel through the co-condensation of methyltriethoxysilane and tetraethyl silicate. The addition of methyltriethoxysilane improves the water vapor corrosion resistance and thermal stability of the silica aerogel, and reduces its insulation performance by inhibiting gas-phase and solid-phase heat transfer. Therefore, the high-performance silica aerogel powder of this invention not only exhibits excellent water vapor corrosion resistance and insulation performance but also possesses excellent high-temperature resistance, maintaining its structure and properties well even at 1300℃.

[0040] The high-performance ceramic matrix composite material for UAVs was prepared using the aforementioned method.

[0041] The application of the high-performance ceramic matrix composite material for UAVs in the fuselage and wing materials of UAVs.

[0042] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0043] 1. The high-performance ceramic matrix composite material for UAVs of the present invention comprises, from the inside out, a silicon carbide fiber-reinforced silicon carbide ceramic matrix, an adhesive layer, a heat-insulating and water-resistant layer, a thermal expansion buffer layer, an oxygen barrier layer, and an aerogel coating. The heat-insulating and water-resistant AlHfTaO6 ceramic coating improves the high-temperature resistance and water vapor resistance of the silicon carbide fiber-reinforced silicon carbide ceramic matrix; the thermal expansion buffer layer TmTa3O9 ceramic coating is located between the heat-insulating and water-resistant layer and the oxygen barrier layer, reducing the difference in thermal expansion coefficients between the two layers; the oxygen barrier layer (Y 1 / 6Dy 1 / 6 Sm 1 / 6 Er 1 / 6 Yb 1 / 6 Gd 1 / 6 The TaO4 high-entropy ceramic coating has excellent high-temperature resistance, thermal insulation, and oxygen barrier and anti-oxidation properties; the aerogel coating has water vapor corrosion resistance, thermal insulation, and high-temperature resistance. The layers work together to give the high-performance ceramic matrix composite material for UAVs of the present invention excellent high-temperature resistance, anti-oxidation properties, thermal insulation properties, and water vapor corrosion resistance.

[0044] 2. The adhesive layer of the present invention has excellent high temperature resistance and good thermal expansion coefficient matching with the silicon carbide fiber reinforced silicon carbide ceramic matrix. The heat insulation and water-resistant layer and the aerogel coating also play a good protective role for the adhesive layer, preventing the adhesive layer from being corroded by water vapor.

[0045] 3. The silicon carbide fiber reinforced silicon carbide ceramic matrix, adhesive layer, heat insulation and water-resistant layer, thermal expansion buffer layer and oxygen barrier layer of the present invention have compatible coefficients of thermal expansion, and the aerogel coating maintains a good connection effect with the inner ceramic material, thus extending the service life of high-performance ceramic matrix composite materials for UAVs.

[0046] 4. The high-performance ceramic matrix composite material for drones of the present invention can be used in the fuselage, wings and other components of drones, enabling drones to be used in high temperature and water vapor environments, thus broadening the application scenarios of drones. In addition, the high-performance ceramic matrix composite material for drones of the present invention also has good oxygen barrier and anti-oxidation properties and heat insulation properties, which play a good protective role for the internal structural components of drones and extend the service life of drones. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the structure of the high-performance ceramic matrix composite material for drones of the present invention;

[0048] Figure 2 This is a comparison chart of the thermal cycling test results of the high-performance ceramic matrix composite materials for UAVs prepared in Examples 2-4 and Comparative Examples 3-9 of this invention;

[0049] Figure 3 This is a comparison chart of the water vapor corrosion mass change rate test of the high-performance ceramic matrix composite materials for UAVs prepared in Examples 2-4 and Comparative Examples 3-9 of this invention;

[0050] Figure 4 This is a comparison chart of the thermal insulation and cooling gradient test results of the high-performance ceramic matrix composite materials for UAVs prepared in Examples 2-4 and Comparative Examples 3-9 of this invention.

[0051] in, Figure 1In the middle: 1 is silicon carbide fiber reinforced silicon carbide ceramic matrix, 2 is adhesive layer, 3 is heat insulation and water resistant layer, 4 is thermal expansion buffer layer, 5 is oxygen barrier layer, and 6 is aerogel coating. Detailed Implementation

[0052] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0053] Example 1

[0054] This embodiment discloses a method for preparing high-performance silica aerogel powder, including the following steps:

[0055] Step S1: At 25℃, 225 mL of deionized water, 450 mL of ethanol, and 0.06 mL of 36 wt% hydrochloric acid aqueous solution were mixed and stirred for 5 min. Then, 120 mL of phenyltrimethoxysilane, 28.5 mL of ethyl silicate, and 17.5 mL of methyltrimethoxysilane were added, and stirring was continued for 7 h to obtain a mixture. The above mixture was added to 2100 mL of 4 wt% ammonia aqueous solution, and stirring was continued for 48 h. After stirring was completed, the mixture was centrifuged. The centrifuged product was washed with ethanol and deionized water, dried, and the dried product was heated to 1000℃ at a rate of 5℃ / min and pyrolyzed for 125 min to obtain SiOC nanospheres.

[0056] Step S2: SiOC nanospheres, deionized water, ethanol, and 25wt% ammonia solution are mixed and heated to 75℃ to obtain mixture A; ethyl silicate and methyltriethoxysilane are mixed at a molar ratio of 1:1.3 and heated to 75℃ to obtain mixture B; mixture A and mixture B are mixed and stirred for 24 hours, concentrated under vacuum, and the solvent is replaced with ethanol to obtain 19wt% monodisperse modified silica sol; wherein, in the mixed system composed of mixture A and mixture B, the concentration of ethyl silicate is 0.18 mol / L, the mass ratio of deionized water to ethyl silicate is 126.8:1, the concentration of ammonia is 0.12 mol / L, and the amount of SiOC nanospheres is 10.5% of the total mass of ethyl silicate and methyltriethoxysilane;

[0057] Monodisperse modified silica sol was gelled in a 50°C water bath. After gelation, the sample was aged at 50°C for 2 days. Then, it was dried by supercritical ethanol at 265°C and 7MPa. The dried sample was then heated at 500°C for 2 hours in air, pulverized, and ground to obtain high-performance silica aerogel powder with a particle size of 15μm.

[0058] Example 2

[0059] This embodiment discloses a method for preparing a high-performance ceramic matrix composite material for unmanned aerial vehicles (UAVs), comprising the following steps:

[0060] Step 1: Mix tantalum silicide powder and tantalum oxide powder at a mass ratio of 9:1 to obtain a raw material composite powder; mix the raw material composite powder, gum arabic, ammonium citrate, and deionized water at a mass ratio of 41.5:1:0.8:50, ball mill, spray granulate, and sieve to obtain a binder layer mixed powder with a particle size of 32μm; wherein, the grinding balls used in the ball milling process are zirconia grinding balls, the ball-to-material ratio is 1:1, and the ball milling time is 45h;

[0061] A silicon carbide fiber-reinforced silicon carbide ceramic matrix was preheated to 500°C using a plasma flame. Then, the aforementioned binder layer mixed powder was sprayed onto the silicon carbide fiber-reinforced silicon carbide ceramic matrix using atmospheric plasma spraying technology to form a binder layer with a thickness of 50 μm. The spraying conditions were as follows: spraying power of 42 kW, spraying distance of 100 mm, argon as the protective gas, hydrogen as the combustion gas, argon flow rate of 35 slpm, hydrogen flow rate of 12 slpm, feed rate of 50 g / min, spray gun speed of 300 mm / s, and spraying time of 2 min.

[0062] Step 2: Alumina powder, hafnium dioxide powder, and tantalum oxide powder are mixed in a molar ratio of 1:2:1 and ball-milled with ethanol as the medium. The resulting slurry is dried at 55°C for 30 hours and then passed through a 120-mesh sieve. The resulting solid particles are reacted at 1550°C for 13 hours to obtain AlHfTaO6 powder. The grinding balls used in the ball milling process are zirconium oxide grinding balls, the ball-to-powder ratio is 3:1, and the ball milling time is 6 hours.

[0063] The AlHfTaO6 powder was sprayed onto the surface of the adhesive layer using supersonic atmospheric plasma spraying technology to form a 100μm thick heat-insulating and water-resistant AlHfTaO6 ceramic coating. The spraying conditions were as follows: spraying power of 50kW, spraying distance of 100mm, argon as the protective gas, hydrogen as the combustion gas, argon flow rate of 68slpm, hydrogen flow rate of 5slpm, feed rate of 25g / min, spray gun speed of 300mm / s, and spraying time of 2min.

[0064] Step 3: Mix thulium oxide powder and tantalum oxide powder in a molar ratio of 1:3, ball mill with ethanol as the medium, dry the resulting slurry at 65°C for 14 hours, pass it through a 300-mesh sieve, and sinter the resulting solid particles at 1450°C for 13 hours to obtain TmTa3O9 powder; wherein, the grinding balls used in the ball milling process are zirconium oxide grinding balls, the ball-to-powder ratio is 1:1, and the ball milling time is 10 hours;

[0065] The above-mentioned TmTa3O9 powder was sprayed onto the heat-insulating and water-resistant layer using atmospheric plasma spraying technology to form a 30μm thick thermal expansion buffer layer TmTa3O9 ceramic coating. The spraying conditions were as follows: spraying power of 46kW, spraying distance of 150mm, argon as protective gas, hydrogen as combustion gas, argon flow rate of 35slpm, hydrogen flow rate of 12slpm, feed rate of 30g / min, spray gun speed of 300mm / s, and spraying time of 1min.

[0066] Step 4: Mix yttrium oxide powder, dysprosium oxide powder, samarium oxide powder, erbium oxide powder, ytterbium oxide powder, gadolinium oxide powder, and tantalum oxide powder in a molar ratio of 1:1:1:1:1:1:6, and ball mill with ethanol as the medium. The resulting slurry is first rotary evaporated at 75°C for 8 min, then dried at 95°C for 10 h, and passed through a 300-mesh sieve. The resulting solid particles are then calcined at 1250°C for 5.5 h to obtain high-entropy powder. The grinding balls used in the ball milling process are zirconia grinding balls, with a ball-to-powder ratio of 1:1, and the ball milling time is 10 h.

[0067] The high-entropy powder was sprayed onto the thermal expansion buffer layer using atmospheric plasma spraying technology to form an oxygen barrier layer (Y) with a thickness of 30 μm. 1 / 6 Dy 1 / 6 Sm 1 / 6 Er 1 / 6 Yb 1 / 6 Gd 1 / 6 A high-entropy ceramic coating of TaO4 was applied to obtain a high-performance ceramic substrate. The spraying conditions were as follows: spraying power of 42kW, spraying distance of 100mm, argon as protective gas, hydrogen as combustion gas, argon flow rate of 35slpm, hydrogen flow rate of 12slpm, feed rate of 30g / min, spray gun speed of 300mm / s, and spraying time of 1min.

[0068] Step 5: At 24°C, mix 9g of dopamine hydrochloride, 7500mL of Tris-HCl buffer solution with pH 8.5, and 2500mL of ethanol to obtain a modification solution; at 24°C, immerse the oxygen barrier layer of the high-performance ceramic matrix described in Step 4 in the modification solution for 20h, remove, wash, and dry to form a polydopamine-modified oxygen barrier layer, thereby obtaining a pretreated high-performance ceramic matrix;

[0069] High-performance silica aerogel powder, hollow glass microspheres, ethanol, and defoamer TEGO 901W were mixed uniformly in a mass ratio of 60:8:20:0.3 to obtain an aerogel coating. The aerogel coating was then sprayed onto a polydopamine-modified oxygen barrier layer using an airless spraying method. The spraying was repeated twice and dried to form an aerogel coating with a thickness of 2 mm, thereby obtaining a high-performance ceramic matrix composite material for UAVs.

[0070] Example 3

[0071] This embodiment discloses a method for preparing a high-performance ceramic matrix composite material for unmanned aerial vehicles (UAVs), comprising the following steps:

[0072] Step 1: Mix tantalum silicide powder and tantalum oxide powder at a mass ratio of 9:1 to obtain a raw material composite powder; mix the raw material composite powder, gum arabic, ammonium citrate, and deionized water at a mass ratio of 48.2:2:1.5:55, ball mill, spray granulate, and sieve to obtain a binder layer mixed powder with a particle size of 125μm; wherein, the grinding balls used in the ball milling process are zirconia grinding balls, the ball-to-material ratio is 1:2, and the ball milling time is 55h;

[0073] The silicon carbide fiber-reinforced silicon carbide ceramic matrix was preheated to 500°C using a plasma flame. Then, the above-mentioned binder layer mixed powder was sprayed onto the silicon carbide fiber-reinforced silicon carbide ceramic matrix using atmospheric plasma spraying technology to form a binder layer with a thickness of 150 μm. The spraying conditions were as follows: spraying power of 42 kW, spraying distance of 100 mm, argon as protective gas, hydrogen as combustion gas, argon flow rate of 35 slpm, hydrogen flow rate of 12 slpm, feed rate of 50 g / min, spray gun speed of 300 mm / s, and spraying time of 3 min.

[0074] Step 2: Alumina powder, hafnium dioxide powder, and tantalum oxide powder are mixed in a molar ratio of 1:2:1 and ball-milled with ethanol as the medium. The resulting slurry is dried at 65°C for 30 hours and then passed through a 120-mesh sieve. The resulting solid particles are reacted at 1650°C for 11 hours to obtain AlHfTaO6 powder. The grinding balls used in the ball milling process are zirconium oxide grinding balls, the ball-to-powder ratio is 6:1, and the ball milling time is 10 hours.

[0075] The AlHfTaO6 powder was sprayed onto the surface of the adhesive layer using supersonic atmospheric plasma spraying technology to form a 200μm thick heat-insulating and water-resistant AlHfTaO6 ceramic coating. The spraying conditions were as follows: spraying power of 50kW, spraying distance of 100mm, argon as the protective gas, hydrogen as the combustion gas, argon flow rate of 68slpm, hydrogen flow rate of 5slpm, feed rate of 25g / min, spray gun speed of 300mm / s, and spraying time of 3min.

[0076] Step 3: Mix thulium oxide powder and tantalum oxide powder in a molar ratio of 1:3, ball mill with ethanol as the medium, dry the resulting slurry at 75°C for 10 hours, pass it through a 300-mesh sieve, and sinter the resulting solid particles at 1550°C for 11 hours to obtain TmTa3O9 powder; wherein, the grinding balls used in the ball milling process are zirconium oxide grinding balls, the ball-to-powder ratio is 1:2, and the ball milling time is 14 hours;

[0077] The above-mentioned TmTa3O9 powder was sprayed onto the heat-insulating and water-resistant layer using atmospheric plasma spraying technology to form a 50μm thick thermal expansion buffer layer, TmTa3O9 ceramic coating. The spraying conditions were as follows: spraying power of 46kW, spraying distance of 150mm, argon as protective gas, hydrogen as combustion gas, argon flow rate of 35slpm, hydrogen flow rate of 12slpm, feed rate of 30g / min, spray gun speed of 300mm / s, and spraying time of 2min.

[0078] Step 4: Mix yttrium oxide powder, dysprosium oxide powder, samarium oxide powder, erbium oxide powder, ytterbium oxide powder, gadolinium oxide powder, and tantalum oxide powder in a molar ratio of 1:1:1:1:1:1:6, and ball mill with ethanol as the medium. The resulting slurry is first rotary evaporated at 80°C for 5 min, then dried at 100°C for 6 h, and passed through a 300-mesh sieve. The resulting solid particles are then calcined at 1350°C for 4.5 h to obtain high-entropy powder. The grinding balls used in the ball milling process are zirconia grinding balls, with a ball-to-powder ratio of 1:2, and the ball milling time is 10 h.

[0079] The high-entropy powder was sprayed onto the thermal expansion buffer layer using atmospheric plasma spraying technology to form an oxygen barrier layer (Y) with a thickness of 50 μm. 1 / 6 Dy 1 / 6 Sm 1 / 6 Er 1 / 6 Yb 1 / 6 Gd 1 / 6A high-entropy ceramic coating of TaO4 was applied to obtain a high-performance ceramic substrate. The spraying conditions were as follows: spraying power of 42kW, spraying distance of 100mm, argon as protective gas, hydrogen as combustion gas, argon flow rate of 35slpm, hydrogen flow rate of 12slpm, feed rate of 30g / min, spray gun speed of 300mm / s, and spraying time of 3min.

[0080] Step 5: At 26°C, mix 10g of dopamine hydrochloride, 9000mL of Tris-HCl buffer solution with pH 8.5, and 3000mL of ethanol to obtain a modification solution; at 26°C, immerse the oxygen barrier layer of the high-performance ceramic matrix described in Step 4 in the modification solution for 28h, remove, wash, and dry to form a polydopamine-modified oxygen barrier layer, thereby obtaining a pretreated high-performance ceramic matrix;

[0081] High-performance silica aerogel powder, hollow glass microspheres, ethanol, and defoamer TEGO 901W were mixed uniformly in a mass ratio of 75:15:27:0.5 to obtain an aerogel coating. The aerogel coating was then sprayed onto a polydopamine-modified oxygen barrier layer using an airless spraying method. The spraying was repeated three times, and the coating was dried to form an aerogel coating with a thickness of 3 mm, thereby obtaining a high-performance ceramic matrix composite material for UAVs.

[0082] Example 4

[0083] This embodiment discloses a method for preparing a high-performance ceramic matrix composite material for unmanned aerial vehicles (UAVs), comprising the following steps:

[0084] Step 1: Mix tantalum silicide powder and tantalum oxide powder at a mass ratio of 9:1 to obtain a raw material composite powder; mix the raw material composite powder, gum arabic, ammonium citrate, and deionized water at a mass ratio of 44.9:1.5:1.1:52.5, ball mill, spray granulate, and sieve to obtain a binder layer mixed powder with a particle size of 80 μm; wherein, the grinding balls used in the ball milling process are zirconia grinding balls, the ball-to-material ratio is 1:1.5, and the ball milling time is 50 h;

[0085] The silicon carbide fiber-reinforced silicon carbide ceramic matrix was preheated to 500°C using a plasma flame. Then, the above-mentioned binder layer mixed powder was sprayed onto the silicon carbide fiber-reinforced silicon carbide ceramic matrix using atmospheric plasma spraying technology to form a binder layer with a thickness of 100μm. The spraying conditions were as follows: spraying power of 42kW, spraying distance of 100mm, argon as protective gas, hydrogen as combustion gas, argon flow rate of 35slpm, hydrogen flow rate of 12slpm, feed rate of 50g / min, spray gun speed of 300mm / s, and spraying time of 2min.

[0086] Step 2: Alumina powder, hafnium dioxide powder, and tantalum oxide powder are mixed in a molar ratio of 1:2:1 and ball-milled with ethanol as the medium. The resulting slurry is dried at 60°C for 25 hours and then passed through a 120-mesh sieve. The resulting solid particles are reacted at 1600°C for 12 hours to obtain AlHfTaO6 powder. The grinding balls used in the ball milling process are zirconium oxide grinding balls, the ball-to-powder ratio is 4.5:1, and the ball milling time is 8 hours.

[0087] The AlHfTaO6 powder was sprayed onto the surface of the adhesive layer using supersonic atmospheric plasma spraying technology to form a 150μm thick heat-insulating and water-resistant AlHfTaO6 ceramic coating. The spraying conditions were as follows: spraying power of 50kW, spraying distance of 100mm, argon as the protective gas, hydrogen as the combustion gas, argon flow rate of 68slpm, hydrogen flow rate of 5slpm, feed rate of 25g / min, spray gun speed of 300mm / s, and spraying time of 2min.

[0088] Step 3: Mix thulium oxide powder and tantalum oxide powder in a molar ratio of 1:3, ball mill with ethanol as the medium, dry the resulting slurry at 70°C for 12 hours, pass it through a 300-mesh sieve, and sinter the resulting solid particles at 1500°C for 12 hours to obtain TmTa3O9 powder; wherein, the grinding balls used in the ball milling process are zirconium oxide grinding balls, the ball-to-powder ratio is 1:1.5, and the ball milling time is 12 hours;

[0089] The above-mentioned TmTa3O9 powder was sprayed onto the heat-insulating and water-resistant layer using atmospheric plasma spraying technology to form a 40μm thick thermal expansion buffer layer TmTa3O9 ceramic coating. The spraying conditions were as follows: spraying power of 46kW, spraying distance of 150mm, argon as protective gas, hydrogen as combustion gas, argon flow rate of 35slpm, hydrogen flow rate of 12slpm, feed rate of 30g / min, spray gun speed of 300mm / s, and spraying time of 2min.

[0090] Step 4: Mix yttrium oxide powder, dysprosium oxide powder, samarium oxide powder, erbium oxide powder, ytterbium oxide powder, gadolinium oxide powder, and tantalum oxide powder in a molar ratio of 1:1:1:1:1:1:6, and ball mill with ethanol as the medium. The resulting slurry is first rotary evaporated at 77.5℃ for 7 minutes, then dried at 97.5℃ for 8 hours, passed through a 300-mesh sieve, and the resulting solid particles are calcined at 1300℃ for 4 hours to obtain high-entropy powder. The grinding balls used in the ball milling process are zirconia grinding balls, with a ball-to-powder ratio of 1:1.5, and the ball milling time is 9 hours.

[0091] The high-entropy powder was sprayed onto the thermal expansion buffer layer using atmospheric plasma spraying technology to form an oxygen barrier layer (Y) with a thickness of 40 μm. 1 / 6 Dy1 / 6 Sm 1 / 6 Er 1 / 6 Yb 1 / 6 Gd 1 / 6 A high-entropy ceramic coating of TaO4 was applied to obtain a high-performance ceramic substrate. The spraying conditions were as follows: spraying power of 42kW, spraying distance of 100mm, argon as protective gas, hydrogen as combustion gas, argon flow rate of 35slpm, hydrogen flow rate of 12slpm, feed rate of 30g / min, spray gun speed of 300mm / s, and spraying time of 1min.

[0092] Step 5: At 25°C, mix 9.5g of dopamine hydrochloride, 8250mL of Tris-HCl buffer solution with pH 8.5, and 2750mL of ethanol to obtain a modification solution; at 25°C, immerse the oxygen barrier layer of the high-performance ceramic matrix described in Step 4 in the modification solution for 24h, remove, wash, and dry to form a polydopamine-modified oxygen barrier layer, thereby obtaining a pretreated high-performance ceramic matrix;

[0093] High-performance silica aerogel powder, hollow glass microspheres, ethanol, and defoamer TEGO 901W were mixed uniformly in a mass ratio of 67.5:11.5:23.5:0.4 to obtain an aerogel coating. The aerogel coating was then sprayed onto a polydopamine-modified oxygen barrier layer using an airless spraying method. The spraying was repeated twice and dried to form an aerogel coating with a thickness of 2.5 mm, thereby obtaining a high-performance ceramic matrix composite material for UAVs.

[0094] The high-performance silica aerogel powder in Examples 2-4 above is the high-performance silica aerogel powder prepared in Example 1.

[0095] Comparative Example 1

[0096] Compared with Example 1, Comparative Example 1 did not add SiOC nanospheres during the preparation of high-performance silica aerogel powder, while other conditions remained unchanged.

[0097] Comparative Example 2

[0098] Compared with Example 1, Comparative Example 2 used an equal amount of ethyl silicate instead of methyltriethoxysilane in the preparation of high-performance silica aerogel powder, while keeping other conditions unchanged.

[0099] Comparative Example 3

[0100] Compared with Example 4, Comparative Example 3 used the high-performance silica aerogel powder prepared in Comparative Example 1 in the process of preparing high-performance ceramic matrix composite material for UAVs, while keeping other conditions unchanged.

[0101] Comparative Example 4

[0102] Compared with Example 4, Comparative Example 4 used the high-performance silica aerogel powder prepared in Comparative Example 2 in the process of preparing high-performance ceramic matrix composite material for UAVs, while keeping other conditions unchanged.

[0103] Comparative Example 5

[0104] Compared with Example 4, Comparative Example 5 did not modify the high-performance ceramic matrix with polydopamine or spray aerogel coating during the preparation of the high-performance ceramic matrix composite material for UAVs. That is, the high-performance ceramic matrix obtained in step four of this comparative example is the final product - the high-performance ceramic matrix composite material for UAVs, and all other conditions remain unchanged.

[0105] Comparative Example 6

[0106] Compared with Example 4, Comparative Example 6 uses supersonic atmospheric plasma spraying technology to spray the AlHfTaO6 powder onto a silicon carbide fiber-reinforced silicon carbide ceramic matrix during the preparation of the high-performance ceramic matrix composite material for UAVs. That is, the high-performance ceramic matrix composite material for UAVs in this comparative example does not contain an adhesive layer, and all other conditions remain unchanged.

[0107] Comparative Example 7

[0108] Compared with Example 4, Comparative Example 7 uses atmospheric plasma spraying technology to spray the above-mentioned TmTa3O9 powder onto the adhesive layer during the preparation of high-performance ceramic matrix composite material for UAVs. That is, the high-performance ceramic matrix composite material for UAVs in this comparative example does not contain a heat insulation and water-resistant layer, and other conditions remain unchanged.

[0109] Comparative Example 8

[0110] Compared with Example 4, Comparative Example 8 uses atmospheric plasma spraying technology to spray the high-entropy powder onto the heat-insulating and water-resistant layer during the preparation of the high-performance ceramic matrix composite material for UAVs. That is, the high-performance ceramic matrix composite material for UAVs in this comparative example does not contain a thermal expansion buffer layer, and all other conditions remain unchanged.

[0111] Comparative Example 9

[0112] Compared with Example 4, Comparative Example 9, in the process of preparing high-performance ceramic matrix composite material for UAVs, immersed the thermal expansion buffer layer of the high-performance ceramic matrix described in step four in the modified liquid. That is, the high-performance ceramic matrix composite material for UAVs in this comparative example does not contain an oxygen barrier layer, and other conditions remain unchanged.

[0113] Experimental Example

[0114] Samples of high-performance ceramic matrix composite materials for UAVs prepared in Examples 2-4 and Comparative Examples 3-9 were taken, and the performance of each group of samples was tested.

[0115] Test 1: The surface of the coating of each group of samples was heated to 1000℃ using a flame and held for 3 minutes, followed by cooling for 2 minutes. This cycle was repeated until the coating peeled off or the material lost more than 10% of its weight due to oxidation. The number of thermal cycles was used to characterize the high temperature resistance of each group of samples. The temperature difference between the surface temperature of the coating and the temperature at the interface between the substrate and the coating during the first test of each group of samples was used as the thermal insulation and cooling gradient of the coating material. The thermal insulation performance of each group of samples was characterized by the thermal insulation and cooling gradient.

[0116] Test 2: Place each group of samples (10 mm in diameter and 3 mm in thickness) into a tube furnace, and introduce a water / air mixture (9:1 volume ratio) at a flow rate of 40 mL / min. Heat the sample to 1300 °C at a rate of 5 °C / min, and allow it to stand at 1300 °C for 20 hours. Then cool the sample to 700 °C at a rate of 10 °C / min, and allow it to cool naturally to room temperature. This completes one water vapor corrosion test cycle. A total of 10 cycles (200 hours) are performed. Record the mass before and after the test, and calculate the water vapor corrosion mass change rate w using the following formula:

[0117] w = (m1 - m0) / m0 × 100%;

[0118] Where: m1 is the mass of the sample after the 10th water vapor cycle, and m0 is the initial mass of the sample;

[0119] Note: The greater the rate of mass change, the worse the sample's resistance to water vapor corrosion.

[0120] The test results are shown in Table 1:

[0121] Table 1

[0122] As shown in Table 1, the high-performance ceramic matrix composites for UAVs prepared in Examples 2-4 of this invention exhibit excellent high-temperature resistance, thermal insulation, and water vapor corrosion resistance. A comparison of Comparative Examples 3-5 with Example 4 reveals that the high-performance silica aerogel powder of this invention, due to its preparation method, the addition of SiOC nanospheres and methyltriethoxysilane, possesses excellent high-temperature resistance, thermal insulation, and water vapor corrosion resistance, thus endowing the high-performance ceramic matrix composites for UAVs with excellent comprehensive performance. A comparison of Comparative Examples 6 and 9 with Example 4 shows that the presence of the adhesive layer and thermal expansion buffer layer in the high-performance ceramic matrix composites for UAVs improves the adhesion of the ceramic coating and its resistance to high-temperature cracking, thereby enhancing the excellent comprehensive performance of the high-performance ceramic matrix composites for UAVs. A comparison of Comparative Example 7 with Example 4 shows that the performance of the high-performance ceramic matrix composites for UAVs is also improved due to the high-temperature resistance, thermal insulation, and water vapor resistance of the AlHfTaO6 ceramic coating.

[0123] Test 3: The high-entropy powder prepared in Example 4 was first pressed under a pressure of 70 MPa, and then heat-treated at 1600℃ for 5 h to obtain (Y 1 / 6 Dy 1 / 6 Sm 1 / 6 Er 1 / 6 Yb 1 / 6 Gd 1 / 6 TaO4 high-entropy ceramic materials; the oxygen ion conductivity of each group of materials at 800℃, 850℃, and 900℃ was tested using an electrochemical workstation (Bio-Logic SP-300, France).

[0124] The test results are shown in Table 2:

[0125] Table 2

[0126] ; As can be seen from the test results in Table 2, the high-entropy powder prepared in Example 4 of this invention is processed into (Y) 1 / 6 Dy 1 / 6 Sm 1 / 6Er 1 / 6 Yb 1 / 6 Gd 1 / 6 The oxygen ion conductivity of the TaO4 high-entropy ceramic sample at 800℃, 850℃, and 900℃ was 1.1×10⁻⁶. -6 S / cm, 1.9×10 -6 S / cm and 3.2×10 -6The oxygen ion conductivity of commonly used oxygen-barrier ceramic materials, such as yttrium-stabilized zirconia (YSZ) at 800℃, 850℃, and 900℃, is 0.01432 S / cm, 0.0229 S / cm, and 0.03471 S / cm, respectively. The oxygen ion conductivity of YbTaO4 ceramic material at 800℃, 850℃, and 900℃ is 5.6 × 10⁻⁶ S / cm. - 6 S / cm, 9.4×10 -6 S / cm and 14×10 -6 S / cm, therefore the (Y) of the present invention 1 / 6 Dy 1 / 6 Sm 1 / 6 Er 1 / 6 Yb 1 / 6 Gd 1 / 6 TaO4 high-entropy ceramic material has excellent oxygen barrier properties. When used in the high-performance ceramic matrix composite material for UAVs of the present invention, it can endow the high-performance ceramic matrix composite material for UAVs with excellent oxygen barrier and oxidation resistance.

[0127] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a high-performance ceramic matrix composite for a drone, characterized by, The method comprises the following steps: Step one, mixing raw material composite powder composed of tantalum silicide powder and tantalum oxide powder, gum arabic, ammonium citrate and deionized water to prepare a bonding layer mixed powder; Spraying the bonding layer mixed powder on a silicon carbide fiber reinforced silicon carbide ceramic matrix by atmospheric plasma spraying technology to prepare a bonding layer with a thickness of 50-150 microns; Step two, spraying AlHfTaO6 powder on the bonding layer of step one by supersonic atmospheric plasma spraying technology to prepare a heat-insulating water-resistant layer with a thickness of 100-200 microns; Step three, spraying TmTa3O9 powder on the heat-insulating water-resistant layer of step two by atmospheric plasma spraying technology to prepare a thermal expansion buffer layer with a thickness of 30-50 microns; Step four, preparing a high-entropy powder with yttrium oxide powder, dysprosium oxide powder, samarium oxide powder, erbium oxide powder, ytterbium oxide powder, gadolinium oxide powder and tantalum oxide powder as raw materials; Spraying the high-entropy powder on the thermal expansion buffer layer of step three by atmospheric plasma spraying technology to prepare an oxygen barrier layer with a thickness of 30-50 microns, thereby obtaining a high-performance ceramic matrix; Step five, modifying the oxygen barrier layer of step four with polydopamine, and then spraying aerogel coating containing high-performance silica aerogel powder on the polydopamine-modified oxygen barrier layer by airless spraying technology to prepare an aerogel coating layer with a thickness of 2-3 mm, thereby obtaining a high-performance ceramic matrix composite material for unmanned aerial vehicles; The preparation method of the high-performance silica aerogel powder comprises the following steps: Step S1, mixing deionized water, ethanol and hydrochloric acid aqueous solution at 24-26 DEG C, then adding phenyltrimethoxysilane, ethyl silicate and methyltrimethoxysilane, continuing to stir for 6-8 hours to obtain a mixed solution; adding the above mixed solution into an ammonia solution, continuing to stir for 44-52 hours, centrifuging, washing, drying, pyrolyzing the dried product at 950-1050 DEG C for 100-150 minutes to obtain SiOC nanospheres; wherein the volume ratio of deionized water, ethanol, hydrochloric acid aqueous solution, phenyltrimethoxysilane, ethyl silicate, methyltrimethoxysilane and ammonia solution is (150-300):(300-600):(0.04-0.08):(80-160):(19-38):(11-22):(1400-2800). Step S2, the SiOC nanospheres, deionized water, ethanol and 25wt% ammonia solution are mixed, heated to 74-76℃, to obtain a mixed solution A; the ethyl silicate and methyl triethoxysilane are mixed in a molar ratio of 1:(1.2-1.4), heated to 74-76℃, to obtain a mixed solution B; the mixed solution A and the mixed solution B are mixed, stirred for 22-26h, vacuum concentrated and solvent replaced with ethanol, to obtain 18-20wt% monodisperse modified silica sol; wherein, in the mixed system composed of the mixed solution A and the mixed solution B, the concentration of the ethyl silicate is 0.18mol / L, the mass ratio of the deionized water to the ethyl silicate is 126.8:1, the concentration of the ammonia water is 0.1-0.15mol / L, and the amount of the SiOC nanospheres is 9-12% of the total mass of the ethyl silicate and the methyl triethoxysilane; The monodisperse modified silica sol is gelled in a 48-52℃ water bath, after gelling, the sample is aged at 48-52℃ for 2 days, dried, and then the dried sample is heated at 490-510℃ for 1.5-2.5h in an air atmosphere, crushed and ground, to obtain high-performance silica aerogel powder with a particle size of 10-20μm.

2. The method of claim 1, wherein the high-performance ceramic matrix composite material for drones is prepared by the steps of: preparing a ceramic matrix composite material by mixing a ceramic matrix material and a ceramic fiber material; and coating the ceramic matrix composite material with a coating material. The thermal expansion coefficient of the silicon carbide fiber reinforced silicon carbide ceramic matrix is 4.5-5.5*10 -6 K -1 The thermal expansion coefficient of the adhesive layer is 5.88-7.04*10 -6 K -1 The thermal expansion coefficient of the thermal insulation water-resistant layer is 5.0-8.0*10 -6 K -1 The thermal expansion coefficient of the thermal expansion buffer layer is 6.0-9.0*10 -6 K -1 The thermal expansion coefficient of the oxygen barrier layer is 9.0-10.1*10 -6 K -1 .

3. The method of claim 1, wherein the high-performance ceramic matrix composite material for drones is prepared by the steps of: preparing a ceramic matrix composite material by mixing a ceramic matrix material and a ceramic fiber material; and coating the ceramic matrix composite material with a coating material. In the step one, the preparation method of the bonding layer is: The tantalum silicide powder and the tantalum oxide powder are mixed in a mass ratio of 9:1 to obtain a raw material composite powder; the raw material composite powder, the gum arabic, the ammonium citrate, the deionized water are mixed in a mass ratio of (41.5-48.2):(1-2):(0.8-1.5):(50-55), ball milled, spray granulated, and sieved to obtain a bonding layer mixed powder with a particle size of 32-125μm; The silicon carbide fiber reinforced silicon carbide ceramic matrix is preheated to 500℃, and then the above bonding layer mixed powder is sprayed on the silicon carbide fiber reinforced silicon carbide ceramic matrix by atmospheric plasma spraying technology to form a bonding layer. 4.The method for preparing high-performance ceramic matrix composites for unmanned aerial vehicles according to claim 1, characterized in that, In the step two, the preparation method of the heat insulation and water resistance layer is: The alumina powder, the hafnium dioxide powder and the tantalum oxide powder are mixed in a molar ratio of 1:2:1, ball milled in ethanol as a medium, and then the obtained slurry is dried at 55-65℃ for 20-30h, sieved through a 120 mesh sieve, and the obtained solid particles are reacted at 1550-1650℃ for 11-13h to obtain an AlHfTaO6 powder; The above AlHfTaO6 powder is sprayed on the surface of the bonding layer by supersonic atmospheric plasma spraying technology to form a heat insulation and water resistance layer. 5.The method for preparing high-performance ceramic matrix composites for drones according to claim 1, characterized in that, In the step three, the preparation method of the thermal expansion buffer layer is: The thulium oxide powder and the tantalum oxide powder are mixed in a molar ratio of 1:3, ball milled in ethanol as a medium, and then the obtained slurry is dried at 65-75℃ for 10-14h, sieved through a 300 mesh sieve, and the obtained solid particles are sintered at 1450-1550℃ for 11-13h to obtain a TmTa3O9 powder; The above TmTa3O9 powder is sprayed on the heat insulation and water resistance layer by atmospheric plasma spraying technology to form a thermal expansion buffer layer. 6.The method for preparing high-performance ceramic matrix composites for drones according to claim 1, characterized in that, In the step four, the preparation method of the high-performance ceramic matrix is: Mixing yttrium oxide powder, dysprosium oxide powder, samarium oxide powder, erbium oxide powder, ytterbium oxide powder, gadolinium oxide powder and tantalum oxide powder in a molar ratio of 1:1:1:1:1:1:6, ball milling in ethanol medium, first rotary evaporation of the obtained slurry at 75-80℃ for 5-8min, then drying at 95-100℃ for 6-10h, passing through a 300 mesh sieve, calcining the obtained solid particles at 1250-1350℃ for 4.5-5.5h, to obtain high-entropy powder; Spray the above high-entropy powder on the thermal expansion buffer layer by atmospheric plasma spraying technology to form an oxygen barrier layer, thereby obtaining a high-performance ceramic matrix. 7.The method for preparing high-performance ceramic matrix composites for drones according to claim 1, characterized in that, In the fifth step, the preparation method of the high-performance ceramic matrix composite material for unmanned aerial vehicles: Mixing dopamine hydrochloride, Tris-HCl buffer solution and ethanol at a ratio of (9-10)g:(7500-9000)mL:(2500-3000)mL at 24-26℃ to obtain a modified liquid; immersing the oxygen barrier layer of the high-performance ceramic matrix in the modified liquid at 24-26℃ for 20-28h, taking out, washing, drying to obtain a pretreated high-performance ceramic matrix; Mixing high-performance silica aerogel powder, hollow glass microspheres, ethanol and defoaming agent TEGO 901W uniformly at a mass ratio of (60-75):(8-15):(20-27):(0.3-0.5) to obtain an aerogel coating; spraying the above aerogel coating on the polydopamine modified oxygen barrier layer by airless spraying, repeating the spraying 2-3 times, drying to form an aerogel coating, thereby obtaining a high-performance ceramic matrix composite material for unmanned aerial vehicles.

8. A high-performance ceramic matrix composite material for unmanned aerial vehicles prepared by the preparation method of the high-performance ceramic matrix composite material for unmanned aerial vehicles according to any one of claims 1-7.

9. The high-performance ceramic matrix composite material for unmanned aerial vehicles according to claim 8 is applied in the body and wing materials of unmanned aerial vehicles.

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