FeNi-C-CNTs-carbon fiber composite material and preparation method and application thereof

Abstract

The invention discloses a FeNi-C-CNTs-carbon fiber composite material and a preparation method and application thereof, and the preparation method comprises the following steps: (1) cutting carbon fibers into short fibers, dispersing the short fibers into fiber bundles, fixing the fiber bundles, and carrying out electrostatic dispersion; (2) spraying an adhesive on the surface of the dispersed carbon fiber to form an adhesive layer on the surface of the carbon fiber, and then pre-curing the adhesive; and (3) carrying out chemical vapor deposition by adopting a horizontal tube furnace and taking a mixture of ferric acetylacetonate and nickel acetylacetonate as a metal precursor. In the FeNi-C-CNTs-carbon fiber composite material, the FeNi alloy nanoparticles and the carbon nanotubes cooperatively construct a three-dimensional conductive network, wave absorbing mechanisms such as magnetic loss, dielectric loss and multiple scattering are strengthened by means of the unique structure, the wave absorbing performance is remarkably improved, the effective frequency band is widened, and the composite material has excellent microwave absorbing performance and structural stability.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of microwave wave-absorbing materials, and particularly relates to a FeNi-C-CNTs-carbon fiber composite material and a preparation method and application thereof. BACKGROUND

[0002] With the wide promotion of 5G and Internet of Things technology, the complexity of electromagnetic wave environment is intensified, and the traditional wave-absorbing body has been difficult to cope with the increasingly improved electromagnetic compatibility requirements. In addition, electronic devices tend to be thin and light, which also puts more stringent restrictions on the thickness and weight of wave-absorbing materials. These diversified application requirements are promoting the evolution of the material towards ultra-thin, wideband and intelligent response, and promoting the research and development boom of a new generation of high-performance wave-absorbing materials.

[0003] The ferrite, metal micro powder / magnetic metal powder and the like in the traditional wave-absorbing material often have inherent defects such as large density, narrow frequency band or insufficient environmental stability in actual application. In recent years, metal-carbon composite nanomaterials have shown great potential due to their adjustable electromagnetic properties and good comprehensive stability. However, the effective compounding of metal and carbon materials still faces challenges such as poor interface compatibility and complex structure regulation, which leads to less ideal wave-absorbing performance. SUMMARY

[0004] The technical problem to be solved by the application is to overcome the deficiencies and defects mentioned in the background, and to provide a FeNi-C-CNTs-carbon fiber composite material, a preparation method thereof and an application thereof as a wave-absorbing material to significantly improve the wave-absorbing performance.

[0005] To solve the above technical problems, the technical solution provided by the application is: A preparation method of a FeNi-C-CNTs-carbon fiber composite material, comprising the following steps: (1) cutting carbon fibers into short fibers and dispersing them into fiber bundles, then fixing the fiber bundles and performing electrostatic dispersion; (2) spraying an adhesive on the surface of the dispersed carbon fibers to form an adhesive layer on the surface of the carbon fibers, and then performing a pre-curing treatment of the adhesive to obtain pretreated carbon fibers; (3) using a horizontal tube furnace, the furnace body is sequentially provided with precursor evaporation zone, reaction zone and deposition zone along the airflow direction, the precursor evaporation zone temperature is controlled at 200-240 DEG C, the reaction zone temperature is set to 900-1000 DEG C, and the deposition zone temperature is maintained at 400-500 DEG C;The mixture of iron acetylacetone and nickel acetylacetone is used as the metal precursor, which is placed in the precursor evaporation zone, and the pretreated carbon fiber is placed in the deposition zone;Hydrogen is used as the carrier gas and the reaction atmosphere, and the vacuum pump system is used to maintain the internal pressure of the system, chemical vapor deposition is carried out, FeNi-C-CNTs is grown on the surface of the carbon fiber, and FeNi-C-CNTs-carbon fiber composite material is obtained.

[0006] As a further improvement, the length of the short fiber in step (1) is 3.0-4.0 cm, and each bundle of the fiber contains 800-1000 monofilament fibers.

[0007] As a further improvement, the fixing in step (1) is to insert the fiber bundle into a porous substrate, one hole for each bundle;The electrostatic dispersion is to use an electrostatic instrument to make the surface of the carbon fiber bundle carry static electricity, and to use the electrostatic repulsion to disperse.

[0008] As a further improvement, the adhesive in step (2) is prepared by mixing phenolic resin, ethylenediamine and anhydrous ethanol in a mass ratio of 8-15:1-2:20-40.

[0009] As a further improvement, the pre-curing treatment in step (2) is to dry in a vacuum dryer at 55~65 DEG C for 1.5~2.5 hours.

[0010] As a further improvement, the distance between the precursor evaporation zone and the reaction zone in step (3) is controlled at 20-30 cm As a further improvement, the molar ratio of iron to nickel in the iron acetylacetone and nickel acetylacetone in step (3) is 1:1.

[0011] As a further improvement, the total gas flow of hydrogen in step (3) is 200-300 sccm, the pressure is maintained at 100-200 Pa, and the reaction lasts for 2-5 hours;After the reaction is completed, the system is naturally cooled to room temperature under the protection of hydrogen atmosphere.

[0012] The FeNi-C-CNTs-carbon fiber composite material provided by the application is prepared by the method, the FeNi alloy nanoparticles in the material are embedded in the carbon matrix and interwoven with the carbon nanotubes to form a three-dimensional conductive network, which is uniformly loaded on the surface of the carbon fiber and jointly constitutes a multi-level composite structure.

[0013] The application further provides application of the FeNi-C-CNTs-carbon fiber composite material.

[0014] Compared with the prior art, the application has the following beneficial effects: In the FeNi-C-CNTs-carbon fiber composite material, FeNi alloy nanoparticles and carbon nanotubes cooperatively construct a three-dimensional conductive network, and by virtue of the unique structure, the microwave absorption mechanisms such as magnetic loss, dielectric loss and multiple scattering are strengthened, the microwave absorption performance is significantly improved, and the effective frequency band is widened.

[0015] The application realizes in-situ growth of FeNi-C-CNTs on carbon fibers by using a chemical vapor deposition method, and can prepare large-area FeNi-C-CNTs-carbon fiber composite materials at one time, and has the advantages of simple process flow, low cost and high efficiency, and overcomes the problems of weak interface bonding and difficult structure control of traditional composite materials. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0017] Figure 1 is a model diagram and an optical microscope picture of carbon fiber bundles inserted into a porous substrate, (a) is a model diagram of carbon fiber bundles inserted into a porous substrate, (b) and (c) are optical microscope pictures, which are a top view and an elevation view, respectively.

[0018] Figure 2 is a scanning electron microscope image (SEM) of carbon fibers and FeNi-C-CNTs-carbon fiber composite materials: (a) SEM image of carbon fibers; (b) low-magnification SEM image of typical FeNi-C-CNTs-carbon fiber composite material; (c) low-magnification SEM picture of S8; (d) low-magnification SEM picture of S12; (e) low-magnification SEM picture of S16; (f) low-magnification SEM picture of S20.

[0019] Figure 3are scanning transmission electron microscope (STEM) and transmission electron microscope (TEM) images of FeNi-C-CNTs-carbon fiber composite material: (a) and (b) are typical STEM image and corresponding TEM image of FeNi-C-CNTs-carbon fiber composite material, respectively; (c) is side STEM image of FeNi-C-CNTs-carbon fiber composite material; (d), (e) and (f) are TEM images of FeNi-C-CNTs at different positions.

[0020] Figure 4 is a formation mechanism diagram of FeNi-C-CNTs-carbon fiber composite material.

[0021] Figure 5 is a two-dimensional reflection loss map of S8 (Example 1).

[0022] Figure 6 is a two-dimensional reflection loss map of S12 (Example 2).

[0023] Figure 7 is a two-dimensional reflection loss map of S16 (Example 3).

[0024] Figure 8 is a two-dimensional reflection loss map of S20 (Example 4). DETAILED DESCRIPTION

[0025] In order to facilitate the understanding of the present application, the following will be combined with the description of the preferred embodiments of the present application and more fully and specifically described, but the protection scope of the present application is not limited to the following specific embodiments.

[0026] Unless otherwise defined, all the professional terms used in the following have the same meaning as that generally understood by the skilled in the art. The professional terms used in the present application are only for the purpose of describing the specific embodiments and are not intended to limit the protection scope of the present application.

[0027] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present application can be purchased from the market or can be prepared by the existing method.

[0028] In some embodiments of the present application, a preparation method of FeNi-C-CNTs-carbon fiber composite material is provided, which comprises two main steps, namely pretreatment of carbon fiber and FeNi-C-CNTs growth.

[0029] Pretreatment of carbon fiber: First, the carbon fibers are cut into short fibers, preferably 3.0-4.0 cm in length; then the cut carbon fibers are dispersed into fiber bundles, preferably each bundle containing 800-1000 single filament fibers. The fiber bundles are fixed to provide support for subsequent processing. For example, the fiber bundles are inserted into the porous substrate as shown in Figure 1 (a) The blue color represents the fiber bundles and the green color represents the porous substrate. The porous substrate has a plurality of holes in the substrate for insertion of the fiber bundles, one bundle per hole.

[0030] Next, the fixed carbon fibers are electrostatically dispersed and sprayed with adhesive. For example, the carbon fiber bundles are given an electrostatic charge using an electrostatic device, and the electrostatic repulsion is used to achieve single filament dispersion as much as possible, avoiding fiber agglomeration. An adhesive is sprayed on the surface of the dispersed carbon fibers. In some embodiments, the adhesive is prepared by mixing and diluting phenol formaldehyde resin (binder), ethylenediamine (curing agent), and anhydrous ethanol (solvent) in a certain mass ratio (8-15: 1-2: 20-40) (the above ratio is the ratio after dilution), and atomizing the mixture using an atomizer to uniformly spray it on the surface of the charged carbon fibers to form a thin and continuous adhesive layer.

[0031] After that, the adhesive is pre-cured to obtain the pre-processed carbon fibers. In some embodiments, the carbon fiber bundles sprayed with adhesive are placed in a vacuum dryer and dried at 55-65°C (preferably 60°C) for 1.5-2.5 hours (preferably 2 hours) to preliminarily cure the adhesive, enhance its bonding force with the fiber surface, and lay a foundation for the carbonization of the adhesive in the subsequent high-temperature stage.

[0032] FeNi-C-CNTs growth: FeNi-C-CNTs are grown on the carbon fibers using a chemical vapor deposition process.

[0033] The FeNi-C-CNTs growth uses a horizontal tube furnace. The furnace body is provided with a precursor evaporation zone, a reaction zone, and a deposition zone along the gas flow direction. Preferably, the distance between the evaporation zone and the reaction zone is controlled to be 20-30 cm, and the distance between the reaction zone and the deposition zone is controlled to be 15-25 cm. The inner diameter of the furnace body is 50-80 mm, and the length is 100-120 cm.

[0034] The mixture of iron acetylacetonate (Fe(acac)3) and nickel acetylacetonate (Ni(acac)2) (iron to nickel molar ratio 1:1, preferably with purity of no less than 97%) is used as the metal precursor, and is placed in the evaporation zone, with the temperature controlled at 200-240°C to make it evaporate into gas; the pretreated carbon fiber (together with the porous substrate) is placed in the deposition zone, with the temperature maintained at 400-500°C; and the temperature of the reaction zone is set at 900-1000°C. Preferably, the mass ratio of the pretreated carbon fiber to (iron acetylacetonate + nickel acetylacetonate) is 1:(30-50).

[0035] Hydrogen is used as the carrier gas and reaction atmosphere, and the total gas flow is preferably controlled at 200-300 sccm (standard cubic centimeter per minute), and the internal pressure of the system is preferably maintained at 100-200 Pa by using a vacuum pump system, and the reaction lasts for 2-5 hours. The decomposed products formed in the reaction zone further generate FeNi-C-CNTs when reaching the carbon fiber. Since the carbon fiber surface has an adhesive, the adhesive is carbonized to form the attachment point of the FeNi-C-CNTs, thereby growing FeNi-C-CNTs on the surface of the carbon fiber, and finally obtaining the FeNi-C-CNTs-carbon fiber composite material.

[0036] Finally, the system is cooled and the sample is collected. After the reaction is completed, the system is naturally cooled to room temperature under the protection of a hydrogen atmosphere, and the sample is taken out, thereby obtaining the final FeNi-C-CNTs-carbon fiber composite material.

[0037] As Figure 4 the mechanism, in this process, the gaseous precursor is transported by the carrier gas to the high-temperature reaction zone for decomposition, and the following main steps are experienced to form FeNi-C-CNTs: Fe(acac)3 and Ni(acac)2 are first decomposed to generate iron, nickel atoms and (acac)· radicals, and the reaction is as follows: Fe(acac)3(g)→Fe(acac)·(g)+(acac)(g), Fe(acac)·(g)→Fe (g)+(acac)·(g), Ni(acac)2(g)→Ni(acac)·(g)+(acac)(g), Ni(acac)·(g)→Ni (g)+(acac)·(g); Iron and nickel atoms condense to form FeNi atom clusters; these clusters further catalyze the decomposition of (acac)· free radicals to produce carbon atoms, which are absorbed to form FeNiC clusters; FeNiC clusters aggregate through collisions, iron and nickel atoms combine to form alloy nanoparticles, while carbon atoms precipitate to form a carbon layer. Small-sized FeNi nanonuclei (diameter less than 10 nm) are encapsulated by the carbon layer to form FeNi-C core-shell nanoparticles, which are tightly attached to the surface of large-sized FeNi-terminated carbon nanotubes through strong surface adsorption. Because small-sized FeNi particles are covered by carbon and have limited dissolved carbon atoms, they easily lose activity and cannot catalyze the growth of carbon nanotubes; while large-sized FeNi nanoparticles can dissolve more carbon atoms, and the carbon layer covering their surface is relatively thin compared to the particle size, thus enabling the catalytic growth of carbon nanotubes. Ultimately, a FeNi-C-CNTs composite structure is constructed. The adhesive pre-coated on the carbon fiber surface forms a large number of active sites after high-temperature carbonization, which effectively promotes the nucleation, attachment and directional growth of FeNi-C-CNTs, and the final product is generated on the carbon fiber surface in the deposition area.

[0038] This FeNi-C-CNTs-carbon fiber composite material uses carbon fiber as a substrate, with FeNi alloy nanoparticles embedded in the carbon matrix (encased in carbon layers) and intertwined with in-situ grown carbon nanotubes to form a three-dimensional conductive network. The nanoparticles are uniformly loaded on the fiber surface, together forming a multi-level composite structure that exhibits excellent broadband microwave absorption performance and good structural stability.

[0039] During implementation, the following six key conditions must be strictly controlled: First, the carbon fiber substrate needs to be cut to a size of 3.0-4.0 mm. Short fiber segments of cm are physically dispersed to form uniform fiber bundles containing 800-1000 monofilaments per bundle (this size and dispersion ensures uniformity of subsequent coating and reaction efficiency), and fixed on a porous substrate (providing a stable support base); secondly, the fiber surface is charged through electrostatic dispersion to achieve monofilament separation (avoiding fiber agglomeration affecting the coating effect), and a binder prepared by phenolic resin, ethylenediamine, and anhydrous ethanol (8-15:1-2:20-40) is sprayed (this ratio can form suitable viscosity and activity) to form a uniform pre-coating; thirdly, the coating is pre-cured in a vacuum environment at 60℃ for 2 hours (promoting the initial cross-linking and curing of the binder), enhancing the bonding force and laying the foundation for the subsequent high-temperature carbonization to generate active sites; fourthly, a zoned temperature-controlled CVD process is adopted, with the evaporation zone at 200-240℃ (ensuring sufficient vaporization of the precursor), the reaction zone at 900-1000℃ (ensuring complete decomposition of the precursor), and the deposition zone at 400-500℃ (providing a suitable temperature for carbon nanotube growth), and the temperature at 200-300℃. SCCM uses hydrogen as the carrier gas (providing a reducing atmosphere and transporting the precursor), and reacts for 2-5 hours at a low pressure of 100-200 Pa (to maintain the environment required for gas-phase reaction) (ensuring sufficient carbon nanotube growth); fifth, the precursor decomposes via free radicals to form FeNi alloy clusters (serving as catalytic active centers), catalyzing the generation of carbon atoms and self-assembling through size-selective effects (<10nm nanonuclei are easily encapsulated by carbon layers to form a core-shell structure), ultimately constructing a FeNi-C-CNTs composite structure; sixth, after the reaction, the sample is cooled to room temperature under hydrogen protection (to prevent oxidation of the sample at high temperatures), ensuring the acquisition of a structurally complete final composite material.

[0040] This invention employs electrostatic dispersion technology and a binder pre-coating process to pretreat carbon fibers. Then, through in-situ growth and heat treatment, using iron acetylacetonate and nickel acetylacetonate as precursors, and precisely controlling the temperature range, pressure, and gas flow parameters of the chemical vapor deposition system, FeNi-C-CNTs are catalytically grown in situ on the carbon fiber surface. The carbonized binder provides attachment sites for the FeNi-C-CNTs, uniformly constructing a multidimensional FeNi-C-CNTs nanostructure on the carbon fiber surface, ultimately forming a FeNi-C-CNTs-carbon fiber composite material with a multi-level composite structure. This not only enhances interfacial polarization and magnetic coupling effects but also significantly optimizes impedance matching characteristics. This multi-scale composite structure effectively integrates magnetic loss and dielectric loss mechanisms, achieving broadband strong absorption and structural functionality.

[0041] Compared with conventional microwave absorbing systems, this composite material exhibits significant advantages in absorption performance, bandwidth, mechanical strength, and environmental friendliness, providing a new strategy for the design and fabrication of next-generation high-performance microwave absorbing materials.

[0042] Example 1 (Low Precursor Load) 1. Pre-treated carbon fiber: The purchased carbon fiber was cut into short fibers with a length of 3.5 cm. The cut carbon fiber was dispersed into bundles, each bundle containing about 900 carbon fibers, and then inserted into a self-made porous substrate for fixation.

[0043] An electrostatic meter is used to charge the carbon fiber bundles with static electricity, allowing them to disperse fully.

[0044] Adhesive preparation: Mix phenolic resin, ethylenediamine, and ethanol in a mass ratio of 10:1.2:30 and stir to dilute. Use an atomizer to spray it evenly onto the surface of the charged carbon fiber.

[0045] The carbon fiber bundles coated with adhesive were placed in a vacuum drying oven at 60°C and dried for 2.5 hours.

[0046] 2. Growth of FeNi-C-CNTs: A horizontal tubular furnace system with an inner diameter of 60 mm and a length of 110 cm was used. The distance between the evaporation zone and the reaction zone was set to 25 cm, and the distance between the reaction zone and the deposition zone was set to 20 cm.

[0047] Weigh a total of 8g of the metal precursor (ferric acetylacetone and nickel acetylacetone with a purity ≥97%, mixed uniformly at a 1:1 iron-nickel molar ratio), place it in a quartz boat, and then place it in the evaporation zone of a tube furnace. Place 0.2g of pretreated carbon fiber in the deposition zone. Set the evaporation zone temperature to 220℃, the reaction zone temperature to 950℃, and the deposition zone temperature to 450℃. Introduce hydrogen gas into the system as a carrier gas, controlling the total flow rate at 250 sccm. Turn on the vacuum pump system to maintain and stabilize the internal pressure of the system at 150 Pa. React under the above conditions for 3 hours.

[0048] After the reaction was completed, the mixture was naturally cooled to room temperature under a hydrogen atmosphere to obtain the FeNi-C-CNTs-carbon fiber composite material.

[0049] Example 2 (Medium precursor load) 1. Pre-treated carbon fiber: The carbon fiber pretreatment steps were exactly the same as in Example 1 (3.5 cm in length, 900 fibers per bundle, adhesive ratio of 10:1.2:30, drying at 60°C for 2.5 hours) to ensure the uniqueness of the variables.

[0050] 2. Growth of FeNi-C-CNTs: The growth equipment and system parameters were kept consistent with those in Example 1 (furnace size, zone spacing, temperature of each zone, carrier gas flow rate, system pressure, and reaction time).

[0051] The only change is that the total mass of the metal precursors (iron acetylacetone and nickel acetylacetone, molar ratio 1:1) is increased to a total of 12g.

[0052] After the reaction was completed, the mixture was naturally cooled to room temperature to obtain the FeNi-C-CNTs-carbon fiber composite material.

[0053] Example 3 (High Precursor Load) 1. Pre-treated carbon fiber: The carbon fiber pretreatment steps are exactly the same as those in Examples 1 and 2.

[0054] 2. Growth of FeNi-C-CNTs: The growth equipment and system parameters are consistent with those in Examples 1 and 2.

[0055] The only change is that the total mass of the metal precursors (iron acetylacetone and nickel acetylacetone, molar ratio 1:1) is increased to a total of 16g.

[0056] After the reaction was completed, the mixture was naturally cooled to room temperature to obtain the FeNi-C-CNTs-carbon fiber composite material.

[0057] Example 4 (Ultra-high precursor load) 1. Pre-treated carbon fiber: The carbon fiber pretreatment steps are the same as those in the previous embodiments.

[0058] 2. Growth of FeNi-C-CNTs: The growth equipment and system parameters can remain unchanged, or to accommodate a larger amount of precursors, the temperature of the evaporation zone can be slightly increased to 240°C to ensure full vaporization.

[0059] Change point: Increase the total mass of the metal precursor to a total of 20g.

[0060] After the reaction was completed, the mixture was naturally cooled to room temperature to obtain the FeNi-C-CNTs-carbon fiber composite material.

[0061] Based on the quality of the precursor in the embodiments, the samples obtained in each embodiment are named S8, S12, S16 and S20, respectively.

[0062] Figure 2The images are scanning electron microscope (SEM) images of carbon fibers and FeNi-C-CNTs-carbon fiber composites: (a) SEM image of carbon fibers; (b) low-magnification SEM image of a typical FeNi-C-CNTs-carbon fiber composite; (c) low-magnification SEM image of S8; (d) low-magnification SEM image of S12; (e) low-magnification SEM image of S16; (f) low-magnification SEM image of S20. In Example 1, the CNT density loaded on the material surface was relatively low, forming a sparse three-dimensional network. In Example 2, compared to Example 1, due to the increased precursor mass, more catalyst particles were generated, and the CNT density grown on the carbon fiber surface was significantly increased, resulting in a denser and more complete three-dimensional conductive network. In Example 3, the CNTs loaded on the carbon fiber surface were extremely dense, almost completely covering the carbon fiber surface, forming a very thick interwoven network. The FeNi-C nanoparticle content was also higher. In Example 4, the CNT growth density in the composite material reached its limit, possibly exhibiting a distinct layered or stacked structure. It should be noted that excessive precursor content may lead to excessively large catalyst particles or agglomeration, which may affect the quality of CNTs and the mechanical properties of composite materials.

[0063] Figure 3 These are scanning transmission electron microscope (STEM) and transmission electron microscope (TEM) images of FeNi-C-CNTs-carbon fiber composite materials: (a) and (b) are typical STEM images and corresponding TEM images of the FeNi-C-CNTs-carbon fiber composite material, respectively; (c) is a side STEM image of the FeNi-C-CNTs-carbon fiber composite material; (d), (e), and (f) are TEM images of FeNi-C-CNTs at different locations. Image (d) illustrates that the material covering the carbon fiber is FeNi-C-CNTs, and image (e) illustrates that the surface of the CNTs is covered with fine FeNi particles.

[0064] Each sample was pressed into a coaxial ring, and its electromagnetic parameters were tested using a vector network analyzer. The reflection loss (RL) value was then calculated based on the electromagnetic parameters. Figure 5 The two-dimensional reflection loss spectrum of S8 samples with different thicknesses (2mm-5mm) is shown in Example 1, with the maximum effective bandwidth being 3.2 GHz. Figure 6 The two-dimensional reflection loss spectrum of S12 samples with different thicknesses (Example 2) shows that the maximum effective bandwidth is 8.8 GHz, which is the optimal sample. Figure 7 This is a two-dimensional reflection loss spectrum of S16 samples with different thicknesses (Example 3), with an effective bandwidth of 6.1 GHz. Figure 8 This is a two-dimensional reflection loss spectrum of S20 samples with different thicknesses (Example 4), with an effective bandwidth of 0 GHz.

[0065] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention should fall within the protection scope of the present invention.

Claims

1. A method for preparing FeNi-C-CNTs-carbon fiber composite material, characterized in that, Includes the following steps: (1) The carbon fiber is cut into short fibers and dispersed into fiber bundles, and then the fiber bundles are fixed and electrostatically dispersed. (2) Spray adhesive onto the surface of dispersed carbon fibers to form an adhesive layer on the surface of the carbon fibers, and then perform pre-curing treatment of the adhesive to obtain pre-treated carbon fibers. (3) A horizontal tube furnace is adopted. The furnace body is arranged with a precursor evaporation zone, a reaction zone and a deposition zone in sequence along the airflow direction. The temperature of the precursor evaporation zone is controlled at 200-240℃, the temperature of the reaction zone is set at 900-1000℃, and the temperature of the deposition zone is maintained at 400-500℃. A mixture of iron acetylacetone and nickel acetylacetone is used as a metal precursor and placed in the precursor evaporation zone. The pretreated carbon fiber is placed in the deposition zone. Hydrogen is used as the carrier gas and reaction atmosphere. The internal pressure of the system is maintained by a vacuum pump system. Chemical vapor deposition is carried out to grow FeNi-C-CNTs on the surface of carbon fiber to obtain FeNi-C-CNTs-carbon fiber composite material.

2. The method for preparing the FeNi-C-CNTs-carbon fiber composite material according to claim 1, characterized in that, The short fiber in step (1) has a length of 3.0-4.0 cm, and each fiber bundle contains 800-1000 monofilament fibers.

3. The method for preparing the FeNi-C-CNTs-carbon fiber composite material according to claim 1 or 2, characterized in that, The fixing in step (1) involves inserting fiber bundles into a porous substrate, with each bundle inserted into one hole; the electrostatic dispersion involves using an electrostatic meter to make the surface of the carbon fiber bundles carry static electricity, and then using electrostatic repulsion to disperse them.

4. The method for preparing the FeNi-C-CNTs-carbon fiber composite material according to claim 1, characterized in that, The adhesive in step (2) is prepared by mixing phenolic resin, ethylenediamine and anhydrous ethanol in a mass ratio of 8-15:1-2:20-40.

5. The method for preparing the FeNi-C-CNTs-carbon fiber composite material according to claim 1 or 4, characterized in that, The pre-curing treatment in step (2) is to dry in a vacuum dryer at 55~65℃ for 1.5~2.5 hours.

6. The method for preparing the FeNi-C-CNTs-carbon fiber composite material according to claim 1, characterized in that, In step (3), the distance between the precursor evaporation zone and the reaction zone is controlled to be 20-30 cm.

7. The method for preparing the FeNi-C-CNTs-carbon fiber composite material according to claim 1 or 6, characterized in that, In step (3), the molar ratio of iron to nickel in iron acetylacetone and nickel acetylacetone is 1:

1.

8. The method for preparing the FeNi-C-CNTs-carbon fiber composite material according to claim 1 or 6, characterized in that, In step (3), the total hydrogen flow rate is 200-300 sccm, the pressure is maintained at 100-200 Pa, and the reaction lasts for 2-5 hours. After the reaction is completed, the system is allowed to cool naturally to room temperature under the protection of hydrogen atmosphere.

9. A FeNi-C-CNTs-carbon fiber composite material, characterized in that, It is prepared by the method described in any one of claims 1 to 8. In this material, FeNi alloy nanoparticles are embedded in a carbon matrix and intertwine with carbon nanotubes to form a three-dimensional conductive network, which is uniformly loaded on the surface of carbon fibers and together constitutes a multi-level composite structure.

10. An application of the FeNi-C-CNTs-carbon fiber composite material according to claim 9, characterized in that, The FeNi-C-CNTs-carbon fiber composite material was used as a microwave absorbing material.

Images