A three-dimensional lattice-structured high-temperature microwave absorbing material based on MXene aerogel / ceramic honeycomb and its preparation method

Abstract

The present invention relates to the technical field of microwave absorbing composite materials, and specifically discloses a three-dimensional lattice structure high-temperature microwave absorbing material based on MXene aerogel / ceramic honeycomb. It is a multi-layer structure, which sequentially includes an oxide ceramic wave-transparent skin, a three-dimensional lattice structure, and a composite material reflection skin from outside to inside. The three-dimensional lattice structure is composed of a honeycomb structure and an MXene composite aerogel microwave absorbing material filling phase filled in the honeycomb structure. The three-dimensional lattice structure high-temperature microwave absorbing material based on MXene aerogel / ceramic honeycomb of the present invention has an effective absorption bandwidth with a reflectivity lower than -10 dB reaching more than 10 GHz, and has broadband microwave absorbing characteristics; using an MXene composite aerogel microwave absorbing material (density 2 mg / cm<supgt;3< / supgt> to 15 mg / cm<supgt;3< / supgt>) and a lightweight ceramic honeycomb structure carrier to form a three-dimensional lattice structure, it has low density characteristics, and at the same time, the effective absorption bandwidth with a reflectivity lower than -10 dB can reach more than 10 GHz, having broadband microwave absorbing performance, and can meet the performance requirements of aircraft lightweight, high-temperature environment, broadband stealth, etc.

Description

Technical Field

[0001] The present invention relates to the technical field of microwave absorbing composite materials, and particularly to a three-dimensional lattice structure high-temperature microwave absorbing material based on MXene aerogel / ceramic honeycomb and a preparation method thereof. Background Art

[0002] Ideal high-temperature radar absorbing materials are required to have multifunctional integrated performance characteristics such as light weight, broadband microwave absorption, high temperature resistance, strong heat insulation, and high strength. However, among the currently reported radar absorbing materials, the effective absorption bandwidth of ferrite-based absorbing materials is generally 6 - 8 GHz, and the density can reach 4.9 - 7.6 g / cm 3 , and the temperature resistance of ferrite absorbing coatings is generally lower than 200 °C due to the need to add polymer binders; although carbon-based absorbing materials have a relatively low density, generally <2 g / cm 3 , but the effective absorption bandwidth is mostly below 10 GHz, and the temperature resistance is lower than 300 °C; the situation of conductive polymer-based absorbing materials is similar to that of carbon-based absorbing materials; after structural design, the absorption bandwidth of microwave absorbing metamaterials based on periodic structure metal patterns and polymer dielectric matrices can reach more than 10 GHz, but the resonance absorption principle causes a large thickness of the matching material required for low-frequency microwave absorption, and the density of metal patterns and polymer dielectric matrices is relatively high, and there are also defects in high temperature resistance and oxidation resistance. As can be seen from the above, the microwave absorbing material system still has performance defects such as high density, narrow absorption bandwidth, and poor temperature resistance. Especially for the high-temperature operating conditions on the surface of hypersonic aircraft equipment, it is difficult to meet the requirements of material density, microwave absorption bandwidth, and heat protection / heat insulation performance. The existing high-temperature microwave absorbing materials are mainly ceramic matrix composite material systems such as SiC, and the electromagnetic wave absorption effect is mainly achieved by modifying absorbing agents with SiC fibers, doping absorbing components in the matrix, etc. Although they have a temperature resistance of >1000 °C and high mechanical strength, on the one hand, due to the relatively single material components, and on the other hand, the structural forms are mostly dense structures such as coatings and solid tiles, resulting in poor adjustability of electromagnetic parameters, high material density, and other problems, as well as the performance defects of narrow effective absorption bandwidth of radar waves (<8 GHz) and obvious structural weight gain. Currently, the existing single-component and single-structure microwave absorbing materials have obvious performance defects such as narrow microwave absorption bandwidth, large material density, and poor temperature resistance, and it is difficult to meet the multifunctional integrated performance requirements of light weight, broadband microwave absorption, high temperature resistance, strong heat insulation, and high strength for the complex force, heat, and electromagnetic service conditions in application scenarios. Summary of the Invention

[0003] The purpose of the present invention is to provide a three-dimensional lattice structure high-temperature microwave absorbing material based on MXene aerogel / ceramic honeycomb and a preparation method thereof, so as to overcome the performance defects of the existing microwave absorbing materials mentioned in the background art, namely narrow microwave absorption bandwidth, large material density, and poor temperature resistance.

[0004] To achieve the above object, the present invention provides a high-temperature wave-absorbing material with a three-dimensional lattice structure based on MXene aerogel / ceramic honeycomb. The high-temperature wave-absorbing material with a three-dimensional lattice structure is a multi-layer structure, which sequentially includes an oxide ceramic wave-transparent skin, a three-dimensional lattice structure, and a composite material reflective skin from outside to inside. The three-dimensional lattice structure is composed of a honeycomb structure and a filling phase of MXene composite aerogel wave-absorbing material filled in the honeycomb structure.

[0005] Preferably, in the above high-temperature wave-absorbing material with a three-dimensional lattice structure based on MXene aerogel / ceramic honeycomb, the oxide ceramic wave-transparent skin and the honeycomb structure are integrated. The materials of the oxide ceramic wave-transparent skin and the honeycomb structure are continuous oxide fiber-reinforced ceramic matrix composites. The oxide fiber is silica fiber or alumina fiber. The thickness of the oxide ceramic wave-transparent skin is 0.5 - 2 mm. The shape of the honeycomb holes in the honeycomb structure is hexagonal, rectangular or triangular. The side length of the honeycomb holes is 0.2 - 1 cm, the thickness of the hole walls is 0.5 - 2 mm, and the thickness of the honeycomb is 5 - 10 mm. The oxide ceramic wave-transparent skin and the honeycomb structure provide functions such as high-temperature resistance, heat insulation, and mechanical load-bearing for the composite material.

[0006] Preferably, in the above high-temperature wave-absorbing material with a three-dimensional lattice structure based on MXene aerogel / ceramic honeycomb, the filling phase of the MXene composite aerogel wave-absorbing material is a high-temperature resistant Ti3C2T x MXene / SiO2 composite aerogel wave-absorbing material, where the mass ratio of Ti3C2T x MXene to SiO2 is 3:7 - 7:3. The filling phase of the MXene composite aerogel material and the honeycomb structure form a three-dimensional lattice structure, which improves the wave-absorbing performance of the high-temperature wave-absorbing material and can also improve the heat insulation function of the high-temperature wave-absorbing material.

[0007] Preferably, in the above high-temperature wave-absorbing material with a three-dimensional lattice structure based on MXene aerogel / ceramic honeycomb, the composite material reflective skin is a carbon fiber resin-based composite material with a thickness of 0.2 - 2 mm. The resin is epoxy resin, bismaleimide resin or polyimide resin. The composite material reflective skin provides a mechanical load-bearing function for the high-temperature wave-absorbing material and reflects electromagnetic waves back into the composite material for secondary absorption.

[0008] The present invention also provides a preparation method of the above high-temperature wave-absorbing material with a three-dimensional lattice structure based on MXene aerogel / ceramic honeycomb, including the following steps:

[0009] (1) Preparation of oxide ceramic wave-transparent skin and honeycomb structure: Cut the oxide ceramic fiber fabric into a suitable shape and size according to the shape and size of the honeycomb, splice and sew to obtain a honeycomb structure ceramic fiber preform skeleton with a single-sided skin. After vacuum impregnating the precursor and high-temperature pyrolysis of the honeycomb structure ceramic fiber preform skeleton, a rough ceramic honeycomb carrier is obtained, and after densification treatment, an integrated carrier of oxide ceramic wave-transparent skin and honeycomb structure is obtained;

[0010] (2) Preparation of MXene composite aerogel material filling phase: Stir the aqueous dispersion of Ti3C2T x MXene two-dimensional nanomaterial and aqueous silica sol evenly to obtain a mixed dispersion. Pour the mixed dispersion into the honeycomb pores of the integrated carrier of oxide ceramic wave-transparent skin and honeycomb structure obtained in step (1) until the honeycomb pores are filled. After freezing and solidifying, vacuum freeze-drying is carried out to obtain the MXene composite aerogel material filling phase filled in the honeycomb structure, and a composite layer of oxide ceramic wave-transparent skin and three-dimensional lattice structure is obtained;

[0011] (3) Preparation of composite material reflective skin;

[0012] (4) Bond the composite layer obtained in step (2) and the composite material reflective skin together with a high-temperature adhesive film to obtain a three-dimensional lattice structure high-temperature wave-absorbing material based on MXene aerogel / ceramic honeycomb.

[0013] Preferably, in the above preparation method, in step (1), the precursors are tetraethyl orthosilicate or Al2O3 ceramic powder sol respectively.

[0014] Preferably, in the above preparation method, in step (1), the temperature of high-temperature pyrolysis is 1000 - 1500 °C, and the densification treatment is to repeat the process of vacuum impregnating the precursor and high-temperature pyrolysis until the mass increase of the ceramic honeycomb carrier is less than 1%.

[0015] Preferably, in the above preparation method, in step (2), the total concentration of Ti3C2T x MXene and SiO2 in the mixed dispersion is 2 mg / mL - 15 mg / mL, and the mass ratio of Ti3C2T x MXene and SiO2 is 3:7 - 7:3; Ti3C2T x The aqueous dispersion of MXene two-dimensional nanomaterial is obtained by etching TiAlC2 ceramic particles of MAX phase with a chemical etching agent to obtain a layered structure of Ti3C2T x MXene, and then obtained after washing and peeling. The chemical etching agent is a mixed solution of an acid and lithium fluoride, and the ratio of the acid to lithium fluoride is 10 mL:1 - 5 g.

[0016] Preferably, in the above preparation method, in step (2), the process of vacuum freeze-drying after freezing solid is as follows: place the oxide ceramic wave-transparent skin and the honeycomb structure integrated carrier in a special trough-shaped mold with a metal bottom plate, pour the mixed dispersion liquid into the honeycomb holes until they are filled, pour liquid nitrogen to submerge the metal plate or connect an electric refrigerator or directly place it in the freezing environment of a refrigerator until the mixed dispersion liquid in the honeycomb holes is completely frozen solid, and then carry out drying in a vacuum freeze-dryer to remove moisture.

[0017] Preferably, in the above preparation method, in step (4), the high-temperature adhesive film is a polyimide adhesive film with a temperature resistance of 300 °C, and the bonding method is bonding by hot pressing.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] 1. The three-dimensional lattice structure high-temperature microwave absorbing material based on MXene aerogel / ceramic honeycomb of the present invention has an effective absorption bandwidth with a reflectivity lower than -10 dB reaching more than 10 GHz, having broadband microwave absorption characteristics; using the MXene composite aerogel microwave absorbing material (density 2 mg / cm 3 ~15 mg / cm 3 ) and a lightweight ceramic honeycomb structure carrier to form a three-dimensional lattice structure, having low density characteristics, and at the same time, the effective absorption bandwidth with a reflectivity lower than -10 dB can reach more than 10 GHz, having broadband microwave absorption performance, and can meet the performance requirements such as component lightweight and broadband microwave absorption.

[0020] 2. The three-dimensional lattice structure high-temperature microwave absorbing material based on MXene aerogel / ceramic honeycomb of the present invention uses a low thermal conductivity MXene composite aerogel material (thermal conductivity <0.03 W / m·K) and a ceramic honeycomb heat insulation structure, greatly reducing the thermal conductivity of the material; the temperature resistance can reach 300 °C, having good high-temperature resistance performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for description in the embodiments. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0022] Figure 1 It is a schematic structural diagram of the three-dimensional lattice structure high-temperature microwave absorbing material based on MXene aerogel / ceramic honeycomb of the present invention.

[0023] Figure 2 It is an SEM photograph of the multi-layer Ti3C2T x MXene particles prepared in Example 1 of the present invention.

[0024] Figure 3 is the single-layer Ti3C2T prepared in Example 1 of the present invention x TEM photograph of MXene nanosheets.

[0025] Figure 4 is the reflectivity curve of the high-temperature wave-absorbing material with a three-dimensional lattice structure based on MXene aerogel / ceramic honeycomb in Example 1 of the present invention.

[0026] Figure 5 is the reflectivity curve of the high-temperature wave-absorbing material with a three-dimensional lattice structure based on MXene aerogel / ceramic honeycomb in Example 2 of the present invention.

[0027] Explanation of main reference numerals:

[0028] 1 - Oxide ceramic wave-transparent skin, 2 - Three-dimensional lattice structure, 3 - Composite material reflection skin. Detailed implementation manners

[0029] The following is a detailed description of the specific implementation manners of the present invention, but it should be understood that the protection scope of the present invention is not limited by the specific implementation manners. Unless otherwise defined, all professional terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present invention. Unless otherwise specifically stated, various raw materials, reagents, instruments, and equipment used in the present invention can be obtained through the market or can be prepared by existing methods.

[0030] Example 1

[0031] A high-temperature wave-absorbing material with a three-dimensional lattice structure based on MXene aerogel / ceramic honeycomb is as Figure 1 shown, which is a multi-layer structure. Defining the electromagnetic wave incident direction as the outer surface of the material, it successively includes an oxide ceramic wave-transparent skin, a three-dimensional lattice structure, and a composite material reflection skin from the outside to the inside. The three-dimensional lattice structure is composed of a honeycomb structure and an MXene composite aerogel wave-absorbing material filling phase filled in the honeycomb structure. The oxide ceramic wave-transparent skin and the honeycomb structure are integrated. The materials of the oxide ceramic wave-transparent skin and the honeycomb structure are continuous silica fiber-reinforced silica ceramic matrix composites. The thickness of the oxide ceramic wave-transparent skin is 1 mm. The honeycomb holes of the honeycomb structure are hexagonal in shape, the side length of the honeycomb holes is 5 mm, the thickness of the hole walls is 1 mm, and the thickness of the honeycomb is 10 mm; the MXene composite aerogel wave-absorbing material filling phase is a high-temperature resistant Ti3C2T x MXene / SiO2 composite aerogel wave-absorbing material, which has an oriented pore structure and a density of 5 mg / cm 3 , where Ti3C2T xThe mass ratio of MXene to SiO2 is 3:2; the composite material reflective skin material is a carbon fiber reinforced epoxy resin based composite reflective flat plate with a thickness of 1 mm.

[0032] The preparation method of the three-dimensional lattice structure high-temperature microwave absorbing material based on MXene aerogel / ceramic honeycomb of this embodiment includes the following steps:

[0033] (1) Preparation of oxide ceramic wave-transparent skin and honeycomb structure: According to the parameters such as the thickness of the wave-transparent layer, the shape, size, wall thickness and honeycomb height of the honeycomb holes in the honeycomb structure, the continuous SiO2 ceramic fiber fabric is cut into a suitable shape and size, spliced and sewn to obtain a honeycomb structure ceramic fiber preform skeleton with a single-sided skin. The honeycomb structure ceramic fiber preform skeleton is vacuum impregnated with a precursor, and the precursor is tetraethyl orthosilicate, and sintered in an air atmosphere at 1000 °C for 2 h to obtain a rough blank of the ceramic honeycomb carrier. Repeat the vacuum impregnation-sintering step until the mass increase of the ceramic honeycomb carrier is less than 1%, complete the densification treatment, and use a grinding machine and manual sandpaper to polish the surface to obtain an oxide ceramic wave-transparent skin and honeycomb structure integrated carrier with a wave-transparent skin thickness of 1 mm, a honeycomb hole side length of 5 mm, a hole wall thickness of 1 m, a honeycomb carrier transverse size of 300 mm × 300 mm, and a thickness of 10 mm;

[0034] (2) Preparation of the MXene composite aerogel material filling phase:

[0035] Dissolve 1.5 g of LiF in 30 mL of 9 mol / L concentrated hydrochloric acid to obtain a hydrochloric acid and lithium fluoride mixed etching agent. Add 1 g of MAX phase TiAlC2 ceramic particles with a particle size of 325 mesh to 30 mL of the etching agent, place it in a polytetrafluoroethylene beaker, keep it at a constant temperature of 30 °C in a water bath, and stir at 3000 r / min for 24 h. Subsequently, centrifuge to collect the etched solid powder precipitate, which is the multi-layer structure Ti3C2T x MXene particles, and the scanning electron microscope photograph is as Figure 2 shown;

[0036] Disperse the precipitate into 50 mL of deionized water, centrifuge at 3000 r / min for 5 min to collect again for one washing, and repeat the dispersion-centrifugation washing process until the supernatant PH>6 or the upper layer liquid after centrifugation is no longer transparent, that is, complete the washing process; Disperse the precipitate into 50 mL of deionized water, seal and ultrasonicate for 15 min, and then centrifuge at 9000 r / min for 30 min to collect the upper layer liquid, which is the single-layer Ti3C2T x MXene nanosheet aqueous dispersion, and the transmission electron microscope photograph of Ti3C2T x MXene nanosheets can be seen in Figure 3 ; single-layer Ti3C2T xThe aqueous dispersion of MXene nanosheets and aqueous silica sol are stirred evenly to obtain a mixed dispersion with a total concentration of 5 mg / mL, and the mass ratio of Ti3C2T x MXene nanosheets to SiO2 is 3:2;

[0037] The ceramic wave-transparent skin and the honeycomb structure integrated carrier are placed in a grooved mold with a metal bottom plate. The mixed dispersion is poured into the honeycomb holes until the honeycomb holes are filled. Liquid nitrogen is poured into the mold for cooling and freezing until the mixed solution in the honeycomb holes is completely frozen. Then it is placed in a freeze dryer with a cold well temperature of -40 °C and a vacuum degree of 10 -5 Pa for drying for 5 days to obtain the MXene composite aerogel material filling phase filled in the honeycomb structure, thereby obtaining a composite layer of an oxide ceramic wave-transparent skin and a three-dimensional lattice structure;

[0038] (3) Preparation of the composite material reflection skin: A carbon fiber / epoxy prepreg is alternately laminated at 0° and 90°, and a carbon fiber-reinforced epoxy composite material reflection skin with a thickness of 1 mm is prepared by the method of molding and heating curing;

[0039] (4) Using a polyimide film resistant to 300 °C, the composite layer of the oxide ceramic wave-transparent skin and the three-dimensional lattice structure and the composite material reflection skin are integrally bonded by the method of molding and heating curing. After machining and post-treatment to remove burrs, etc., a three-dimensional lattice structure high-temperature wave-absorbing material based on MXene aerogel / ceramic honeycomb is obtained.

[0040] The overall density of the three-dimensional lattice structure high-temperature wave-absorbing material in this embodiment is 0.5 g / cm 3 , and the electromagnetic wave reflectivity at 1-18 GHz is shown in Figure 4 . As can be seen from the figure, the three-dimensional lattice structure high-temperature wave-absorbing material has a reflectivity < -10 dB at 7.74 - 18.00 GHz and has excellent broadband absorption performance.

[0041] Example 2

[0042] A three-dimensional lattice structure high-temperature wave-absorbing material based on MXene aerogel / ceramic honeycomb is as Figure 1As shown, it is a multi-layer structure. The incident direction of electromagnetic waves is defined as the outer surface of the material, which successively includes an oxide ceramic wave-transparent skin, a three-dimensional lattice structure, and a composite material reflective skin from outside to inside. The three-dimensional lattice structure is composed of a honeycomb structure and an MXene composite aerogel wave-absorbing material filling phase filled in the honeycomb structure. The oxide ceramic wave-transparent skin and the honeycomb structure are integrated. The materials of the oxide ceramic wave-transparent skin and the honeycomb structure are continuous alumina fiber-reinforced alumina ceramic matrix composites. The thickness of the oxide ceramic wave-transparent skin is 0.5 mm. The shape of the honeycomb holes in the honeycomb structure is rectangular, with a length of 8 mm, a width of 4 mm, a pore wall thickness of 2 mm, and a honeycomb thickness of 5 mm; the MXene composite aerogel wave-absorbing material filling phase is a high-temperature-resistant Ti3C2T x MXene / SiO2 composite aerogel wave-absorbing material, which has an oriented pore structure and a density of 10 mg / cm 3 , where Ti3C2T x The mass ratio of MXene and SiO2 is 1:1; the material of the composite material reflective skin is a carbon fiber-reinforced epoxy resin-based composite material reflective plate with a thickness of 2 mm.

[0043] The preparation method of the three-dimensional lattice structure high-temperature wave-absorbing material based on MXene aerogel / ceramic honeycomb in this embodiment includes the following steps:

[0044] (1) Preparation of the oxide ceramic wave-transparent skin and the honeycomb structure: According to the parameters such as the thickness of the wave-transparent layer and the shape, size, wall thickness, and honeycomb height of the honeycomb holes in the honeycomb structure, the continuous Al2O3 ceramic fiber fabric is cut into a suitable shape and size, spliced and sewn to obtain a honeycomb structure ceramic fiber preform skeleton with a single-sided skin. The honeycomb structure ceramic fiber preform skeleton is vacuum-impregnated with a precursor, and the precursor is an aqueous Al2O3 ceramic powder sol. It is sintered in an air atmosphere at 1000 °C for 2 h to obtain a ceramic honeycomb carrier rough blank. The vacuum impregnation-sintering steps are repeated until the material mass increase is less than 1%, and the densification treatment is completed. The surface is processed flat by using a grinding machine and manual sandpaper polishing to obtain an integrated carrier of the oxide ceramic wave-transparent skin and the honeycomb structure with a wave-transparent skin thickness of 0.5 mm, honeycomb holes with a length of 8 mm, a width of 4 mm, a pore wall thickness of 2 mm, a honeycomb carrier transverse size of 300 mm × 300 mm, and a thickness of 5 mm;

[0045] (2) Preparation of the MXene composite aerogel material filling phase:

[0046] Dissolve 2.5 g of LiF in 50 mL of concentrated hydrochloric acid with a concentration of 9 mol / L to obtain a mixed etchant of hydrochloric acid and lithium fluoride. Add 1 g of MAX phase TiAlC2 ceramic particles with a particle size of 325 mesh to 50 mL of the etchant, place it in a polytetrafluoroethylene beaker, keep it at a constant temperature of 40 °C in a water bath, and stir at 3500 r / min for 24 h. Subsequently, centrifuge to collect the etched solid powder precipitate, which is the multi-layer structure Ti3C2T x MXene particles;

[0047] Disperse the precipitate in 50 mL of deionized water, centrifuge at 3000 r / min for 5 min, and collect again to complete one cleaning. Repeat the dispersion-centrifugation cleaning process until the pH of the supernatant > 6 or the upper layer liquid after centrifugation is no longer transparent, that is, complete the washing process; Disperse the precipitate in 50 mL of deionized water, seal and ultrasonicate for 15 min, and then centrifuge at 9000 r / min for 30 min to collect the upper layer liquid, which is the single-layer Ti3C2T x Aqueous dispersion of MXene nanosheets; Single-layer Ti3C2T x Stir the aqueous dispersion of MXene nanosheets and aqueous silica sol evenly to obtain a mixed dispersion with a total concentration of 10 mg / mL, Ti3C2T x The mass ratio of MXene nanosheets to SiO2 is 1:1;

[0048] Place the ceramic wave-transparent skin and the honeycomb structure integrated carrier in a grooved mold with a metal bottom plate. Pour the mixed dispersion into the honeycomb holes until the honeycomb holes are filled. Place the whole mold in a refrigerator at a constant temperature of -18 °C until the mixed solution in the honeycomb holes is completely frozen. Then put it into a freeze dryer with a cold well temperature of -50 °C and a vacuum degree of 10-5 Pa for drying for 7 days to obtain the MXene composite aerogel material filling phase filled in the honeycomb structure, thereby obtaining a composite layer of oxide ceramic wave-transparent skin and three-dimensional lattice structure;

[0049] (3) Preparation of the composite material reflection skin: Use a carbon fiber / epoxy resin prepreg to alternate layers at 0° and 90°, and use a method of molding and heating curing to prepare a carbon fiber reinforced epoxy resin composite material reflection skin with a thickness of 2 mm;

[0050] (4) Use a polyimide film with a temperature resistance of 300 °C and adopt a method of molding and heating curing to realize the integrated bonding of the composite layer of oxide ceramic wave-transparent skin and three-dimensional lattice structure and the composite material reflection skin. After mechanical processing and post-treatment to remove burrs, etc., a three-dimensional lattice structure high-temperature wave-absorbing material based on MXene aerogel / ceramic honeycomb is obtained.

[0051] The three-dimensional lattice structure high-temperature wave-absorbing material of this example has an overall density of 0.7 g / cm 3 , and the electromagnetic wave reflectivity at 1-18 GHz is shown inFigure 5 As can be seen from the figure, the three-dimensional lattice structure high-temperature microwave absorbing material has a reflectivity of less than -10 dB in the frequency range of 7.61 - 18.00 GHz, showing excellent broadband absorption performance.

[0052] The foregoing description of specific exemplary embodiments of the invention has been presented for purposes of illustration and example. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The purpose of selecting and describing exemplary embodiments is to explain the specific principles of the invention and its practical application so that those skilled in the art can implement and utilize the various different exemplary embodiments of the invention, as well as various different selections and modifications. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A three-dimensional lattice-structured high-temperature wave-absorbing material based on MXene aerogel / ceramic honeycomb, characterized in that, The three-dimensional lattice structure high-temperature wave-absorbing material is a multi-layer structure, which sequentially includes an oxide ceramic wave-transparent skin, a three-dimensional lattice structure, and a composite material reflecting skin from the outside to the inside. The three-dimensional lattice structure is composed of a honeycomb structure and an MXene composite aerogel wave-absorbing material filling phase filled in the honeycomb structure; The oxide ceramic wave-transparent skin and the honeycomb structure are integrated. The materials of the oxide ceramic wave-transparent skin and the honeycomb structure are continuous oxide fiber-reinforced ceramic matrix composites. The oxide fiber is silica fiber or alumina fiber. The thickness of the oxide ceramic wave-transparent skin is 0.5 to 2 mm. The shape of the honeycomb holes in the honeycomb structure is hexagonal, rectangular or triangular. The side length of the honeycomb holes is 0.2 to 1 cm. The thickness of the hole walls is 0.5 to 2 mm. The thickness of the honeycomb is 5 to 10 mm. The filling phase of the MXene composite aerogel absorbing material is high-temperature resistant Ti3C2T x MXene / SiO2 composite aerogel absorbing material, where Ti3C2T x The mass ratio of MXene to SiO2 is 3:7 to 7:

3.

2. The three-dimensional lattice structure high-temperature wave-absorbing material based on MXene aerogel / ceramic honeycomb according to claim 1, characterized in that The composite material reflecting skin is a carbon fiber resin-based composite material with a thickness of 0.2-2 mm, and the resin is epoxy resin, bismaleimide resin or polyimide resin.

3. A preparation method of a three-dimensional lattice structure high-temperature wave-absorbing material based on MXene aerogel / ceramic honeycomb as described in any one of claims 1 to 2, characterized in that, It includes the following steps: (1) Preparation of the oxide ceramic wave-transparent skin and the honeycomb structure: Cut the oxide ceramic fiber fabric into a suitable shape and size according to the shape and size of the honeycomb, splice and sew to obtain a honeycomb structure ceramic fiber preform skeleton with a single-sided skin. After vacuum impregnating the precursor and high-temperature pyrolysis of the honeycomb structure ceramic fiber preform skeleton, a ceramic honeycomb carrier rough blank is obtained, and after densification treatment, an integrated carrier of the oxide ceramic wave-transparent skin and the honeycomb structure is obtained; (2) Preparation of the filler phase of the MXene composite aerogel microwave absorption material: Ti3C2T x The aqueous dispersion of the MXene two-dimensional nanomaterial and the aqueous silica sol are stirred evenly to obtain a mixed dispersion. The mixed dispersion is poured into the honeycomb pores of the oxide ceramic microwave-transparent skin and honeycomb structure integrated carrier obtained in step (1) until the honeycomb pores are filled. After freezing and solidifying, it is then subjected to vacuum freeze-drying to obtain the filler phase of the MXene composite aerogel microwave absorption material filled in the honeycomb structure, and a composite layer of the oxide ceramic microwave-transparent skin and the three-dimensional lattice structure is obtained. (3) Preparation of the composite material reflecting skin; (4) Use a high-temperature adhesive film to bond the composite layer obtained in step (2) and the composite material reflecting skin together to obtain a three-dimensional lattice structure high-temperature wave-absorbing material based on MXene aerogel / ceramic honeycomb.

4. The preparation method according to claim 3, characterized in that In the step (1), the precursors are tetraethyl orthosilicate or Al2O3 ceramic powder sol respectively.

5. The preparation method according to claim 3, wherein In the step (1), the high-temperature pyrolysis temperature is 1000-1500 °C, and the densification treatment is to repeat the process of vacuum impregnating the precursor and high-temperature pyrolysis until the mass increase of the ceramic honeycomb carrier is less than 1%.

6. The preparation method according to claim 3, characterized in that, In the step (2), the total concentration of Ti3C2T x MXene and SiO2 in the mixed dispersion liquid is 2 mg / mL to 15 mg / mL, and the mass ratio of Ti3C2T x MXene to SiO2 is 3:7 to 7:3; the aqueous dispersion liquid of Ti3C2T x MXene two-dimensional nanomaterial is obtained by etching TiAlC2 ceramic particles of MAX phase with a chemical etching agent to obtain a layered structure of Ti3C2T x MXene, and then obtained after washing and exfoliation. The chemical etching agent is a mixed solution of an acid and lithium fluoride, and the ratio of the acid to lithium fluoride is 10 mL: 1 to 5 g.

7. The preparation method according to claim 3, wherein In the step (2), the process of freezing and then vacuum freeze-drying is as follows: Place the integrated carrier of the oxide ceramic wave-transparent skin and the honeycomb structure in a special trough-shaped mold with a metal bottom plate. Pour the mixed dispersion liquid into the honeycomb holes until they are filled. Pour liquid nitrogen to submerge the metal plate or connect an electric refrigerator or directly place it in a refrigerator freezing environment until the mixed dispersion liquid in the honeycomb holes is completely frozen, and then dry it in a vacuum freeze-dryer to remove moisture.

8. The preparation method according to claim 3, characterized in that, In the step (4), the high-temperature adhesive film is a polyimide adhesive film with a temperature resistance of 300 °C, and the bonding method is bonding by hot pressing.

Images