A Zn-Fe-Mn oxide-hard carbon composite material, a preparation method and application thereof

Abstract

The application relates to the technical field of wave-absorbing materials, and particularly discloses a Zn-Fe-Mn oxide-hard carbon composite material, a preparation method and application thereof. A pomegranate-shaped sphere is prepared through a co-precipitation-calcination method; then, the pomegranate-shaped sphere is uniformly dispersed in a self-prepared solvent combination, and the mixture is solidified and formed through heating treatment; finally, annealing treatment is carried out on the Zn-Fe-Mn oxide-hard carbon composite material in an 800 DEG C high-temperature tube furnace under an argon protection atmosphere (flow rate: 100 sccm). The composite material has a unique three-dimensional layered structure, exhibits excellent wide-band microwave absorption characteristics, and can realize efficient electromagnetic wave attenuation. The application opens up a new way for the structural design and optimization of high-performance wave-absorbing materials, and has a wide application prospect in the fields of advanced stealth technology and novel electromagnetic shielding applications.

Description

Technical Field

[0001] This invention belongs to the field of microwave absorbing materials, and particularly relates to a Zn-Fe-Mn oxide-hard carbon composite material, its preparation method and application. Background Technology

[0002] With the rapid development of modern technology, devices such as mobile communications, intelligent robots, 5G base stations, satellite navigation, electronic radar, and stealth equipment are widely used in national defense equipment and daily life. While bringing convenience, these devices also cause electromagnetic pollution. For example, electromagnetic interference can affect the normal operation of electronic devices, and electromagnetic radiation can harm human health. Therefore, finding absorbing materials that can attenuate electromagnetic waves and reduce or eliminate electromagnetic pollution is extremely urgent. Traditional absorbing materials (such as ferrites and ceramics) still have shortcomings such as high density, narrow absorption bandwidth, and difficulty in processing. Therefore, exploring broadband and efficient absorbing materials is an urgent problem to be solved.

[0003] Garnet-like metal oxide microspheres have attracted much attention in recent years due to their unique hierarchical porous structure and potential applications in energy, electronics, and catalysis. However, their inherent high density and insufficient dielectric loss limit their practical application performance as microwave absorbing materials. Hard carbon materials, with their abundant structural defects and chemical stability, are ideal conductive components, and their non-graphitized properties generate nanopores and functional groups that can effectively enhance dielectric polarization loss. However, the development of garnet-like metal oxide-hard carbon composite materials currently faces the dual challenges of achieving uniform dispersion of metal oxide nanoparticles and controlling their structural morphology, which are key factors restricting the improvement of their microwave absorption performance.

[0004] Hard carbon materials exhibit unique advantages in the field of microwave absorption: their non-graphitized structural defects, residual functional groups, and nanopores can serve as polarization centers to enhance dielectric loss; simultaneously, their excellent chemical stability and simple synthesis process make them practically valuable. However, when hard carbon is combined with garnet-like metal oxides, maintaining both the uniform dispersion of the metal oxide nanoparticles and the regular garnet-like porous structure presents a significant challenge to the development of such composite materials. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a method for preparing Zn-Fe-Mn oxide-hard carbon composite materials. The Zn-Fe-Mn oxide-hard carbon composite materials prepared by this method form a three-dimensional interconnected network structure through a hard carbon matrix. This unique composite structure can effectively enhance the interfacial polarization effect and multiple scattering mechanism, significantly improve the electromagnetic wave absorption performance of the material, and broaden the effective absorption bandwidth. To a certain extent, it solves the problems of high density, narrow absorption bandwidth, and difficulty in processing of traditional microwave absorbing materials in the prior art.

[0006] This invention provides a Zn-Fe-Mn oxide-hard carbon composite material, its preparation method, and its application. The technical solution proposed by this invention is as follows:

[0007] In a first aspect, the present invention provides a method for preparing a Zn-Fe-Mn oxide-hard carbon composite material, comprising the following steps:

[0008] Step a: Organometallic complexes of Zn, Mn, and Fe are prepared by co-precipitation-calcination method using organometallic complexes of Zn, Mn, and Fe, along with NaHCO3 powder. powder;

[0009] Step b, will The powder was slowly added to the self-made solvent mixture and stirred until homogeneous, thus preparing the product. Mixed solutions;

[0010] Step c: Increase the temperature and increase the stirring speed to fully solidify the mixed solution and obtain the solidified product;

[0011] Step d: The cured product is subjected to high-temperature annealing under an inert atmosphere to carbonize the organic solvent, thereby obtaining a Zn-Fe-Mn oxide-hard carbon composite material.

[0012] Compared to existing technologies, the preparation method of Zn-Fe-Mn oxide-hard carbon composite material provided by this invention first prepares the composite material by co-precipitation-calcination of Zn organometallic complexes, Mn organometallic complexes, Fe organometallic complexes, and NaHCO3 powder. The powder was then processed using a homemade solvent combination. The powder is mixed evenly, and the solution is fully solidified by increasing the temperature and stirring speed. Finally, the organic solvent is carbonized by high-temperature annealing to obtain Zn-Fe-Mn oxide-hard carbon composite material.

[0013] Furthermore, in step a, the organometallic complex of Zn can be Zn(acac)2; the organometallic complex of Mn can be Mn(acac)2; and the organometallic complex of Fe can be Fe(acac)3.

[0014] In this application, the powders of the organometallic complexes of Zn, Mn, and Fe, as well as NaHCO3 powder, are first dissolved in sufficient deionized water to obtain a single solution. Then, all the organometallic complexes and the NaHCO3 solution are mixed and reacted to form a coprecipitate. It should be further noted that, in the specific embodiments of this invention, the organometallic complex of Zn is Zn(acac)2, the organometallic complex of Mn can be Mn(acac)2, and the organometallic complex of Fe can be Fe(acac)3. For example, when Zn(acac)2 and NaHCO3 react in aqueous solution, Zn(acac)2 will dissociate into Zn in the aqueous solution. 2+ With two aacac- radical ions, NaHCO3 completely dissociates into Na+ in aqueous solution. + and HCO3 - HCO3 - In water, secondary dissociation and hydrolysis also occur, HCO3- - Secondary dissociation into H + and CO3 2- HCO3 - Further hydrolysis can produce H2CO3 and OH. - Ions, and acac - It is a weakly basic ligand, and its conjugate acid is acetylacetone (acacH), with a pKa ≈ 9.0. Its acidity is weaker than that of H₂CO₃ in the second-step dissociation (pKa₂ ≈ 10.33). When [Zn(acac)₂] dissociates, the Zn... 2+ With HCO3 - CO3 provided 2- OH - Upon contact, they preferentially combine to form basic zinc carbonate precipitate, continuously shifting the dissociation equilibrium of [Zn(acac)2] in the positive direction (Le Chatelier's principle). Similarly, when the organometallic complexes of Fe(acac)3 and Mn(acac)2 react with NaHCO3 in aqueous solution, they will also combine to form basic iron carbonate precipitate and basic manganese carbonate precipitate. This is because, in this invention, the organometallic complexes of Zn(acac)2, Fe(acac)3, and Mn(acac)2 react simultaneously with the aqueous solution of NaHCO3. When the three metal ions coexist, they react with HCO3... - The reactions occur simultaneously, with each metal ion generating its corresponding basic carbonate. However, because the precipitation process occurs simultaneously, these basic carbonates do not crystallize individually but instead mix with each other and precipitate together, forming a mixed-phase co-precipitate.

[0015] The coprecipitate was then calcined and annealed at high temperature under an inert gas atmosphere to obtain... powder.

[0016] Furthermore, in step b, the self-made solvent combination comprises a carbon source, a curing agent, an organic solvent, and a leavening agent.

[0017] Furthermore, the carbon source may be at least one of phenolic resin and epoxy resin; the curing agent includes ethylenediamine; the organic solvent includes at least one of anhydrous ethanol and acetone; and the leavening agent includes at least one of sodium bicarbonate and sodium carbonate.

[0018] Furthermore, the mass ratio of the carbon source, curing agent, organic solvent, and leavening agent is (10-15):(0.1-1):(0.5-5):(0.5-4), for example, the mass ratio of the carbon source, curing agent, organic solvent, and leavening agent is 10:0.1:0.5:0.2, 11:0.2:1.5:0.8, 12:0.4:2.5:1.5, 13:0.6:3.5:2.5, 14:0.8:4.5:3.5, 15:1:5:4, or any range of any two of the above ratios.

[0019] In one specific embodiment, the mass ratio of carbon source, curing agent, organic solvent, and leavening agent is 12:1:1:1, and the ratio can be adjusted according to actual conditions. Since the curing agent carbonizes under high temperature conditions, potentially requiring additional carbon source, the concentration range of the curing agent is 0.1-1 parts. Because an increased organic solvent content leads to a longer solidification time, the organic solvent content ranges from 0.5-5 parts. In practice, while the leavening agent can increase pores in the product, thereby optimizing its spatial layout, excessive leavening agent content can lead to excessive pores in the product, potentially reducing its microwave absorption performance. Therefore, in this invention, the proportion of leavening agent is 0.5-4 parts.

[0020] This invention, by controlling the content of carbon source, curing agent, organic solvent and leavening agent in the self-made solvent combination, can further optimize the dispersion and mixing process, and ensure the structural uniformity and performance stability of the material.

[0021] Furthermore, the self-made solvent combination with The mass ratio of the powders is (1-6):(1-6). Furthermore, during the experiment, this ratio can be any two of the following: 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 2:1, 2:3, 2:5, 2:6, 3:1, 3:2, 3:4, ..., 6:5, or any range of two ratios above, i.e., the self-made solvent combination and... Any mass ratio of powder within the range of (1-6):(1-6) can achieve the purpose of this invention.

[0022] Furthermore, in step b, the stirring rate is 0.1 rpm to 1.5 rpm, for example, 0.1 rpm, 0.2 rpm, 0.3 rpm, 0.4 rpm, 0.5 rpm, 0.6 rpm, 0.7 rpm, 0.8 rpm, 0.9 rpm, 1.1 rpm, 1.2 rpm, 1.3 rpm, 1.4 rpm, 1.6 rpm, or any range of two of the above ratios. It should be further noted that in step b of this invention, the use of a lower stirring rate is taken into account the result obtained in step a. The powder has a relatively loose structure, and slow stirring can accelerate the process in step a. Powdered self-made solvent combination mixing, without damage The structure of the powder, at the same time making The powder is coated with a self-made solvent blend, and the curing agent in the self-made solvent blend further enhances its properties. The structure of the powder.

[0023] As a further improvement, the self-made solvent combination was slowly added via a syringe pump at a low rate of 0.05 mL / min. In powder, a low-speed injection method can reduce the impact on... The structural disruption of the powder ensures better performance stability of the subsequent Zn-Fe-Mn oxide-hard carbon composite material.

[0024] Furthermore, in step c, the heating temperature is 60℃-90℃, and the stirring rate is 100 rpm-300 rpm, for example, 100 rpm, 120 rpm, 130 rpm, 140 rpm, 150 rpm, 180 rpm, 200 rpm, 220 rpm, 240 rpm, 260 rpm, 270 rpm, 280 rpm, 290 rpm, 300 rpm, or any range of two of the above ratios. In step c, the stirring speed is significantly increased because the self-made solvent combination in step b... The powder coating strengthens the structure of the powder; therefore, the main purpose of step c is to increase the stirring speed so that... The powder can be dispersed quickly and evenly in a self-made solvent combination.

[0025] By using different stirring rates, one slow and one fast, in steps b and c, we can achieve... The powder is uniformly distributed in a solution of a self-made solvent combination, which can further optimize the dispersion and mixing process and ensure the structural uniformity and performance stability of the material.

[0026] Furthermore, in step a, the co-precipitation-calcination method includes the following steps:

[0027] a-1: Dissolve the organometallic complexes of Zn, Mn, and Fe in sufficient deionized water to obtain a single solution;

[0028] a-2: Mix all the single solutions obtained in a-1 to obtain a coprecipitate;

[0029] a-3: The coprecipitate was calcined under an inert gas atmosphere and then annealed at high temperature to obtain... powder.

[0030] Furthermore, in step a-1, the mass ratio of the organometallic complex of Zn, the organometallic complex of Mn, the organometallic complex of Fe, and NaHCO3 is 44:100:(1-60):107.

[0031] Furthermore, the mass ratio of the organometallic complex of Zn, the organometallic complex of Mn, the organometallic complex of Fe, and NaHCO3 is 44:100:(5-40):107.

[0032] Furthermore, in the embodiments of this invention, a single-variable embodiment of the organometallic complex of Fe was designed. The results show that when the content of the organometallic complex of Fe in the system increases, the microwave absorption characteristics of the Zn-Fe-Mn oxide-hard carbon composite material are significantly changed. Similarly, it can be seen that when the mass of the organometallic complexes of Zn and Mn in the system is adjusted alone or in combination, it also has a great influence on the microwave absorption characteristics of the Zn-Fe-Mn oxide-hard carbon composite material.

[0033] Furthermore, in step a-3, the annealing temperature is 800℃-1000℃, for example 800℃, 820℃, 840℃, 860℃, 880℃, 900℃, 920℃, 940℃, 960℃, 980℃, 1000℃, or any range of two of the above ratios. The annealing time is 2-3 hours, and the annealing is carried out under vacuum conditions. During the annealing process, the organic solvent is carbonized. The powder is reduced by carbon and transformed into Zn, Fe and Mn oxides (chemical formulas ZnFe2O4, FeO and MnO, etc.).

[0034] This method ensures the structural uniformity and performance stability of the material by optimizing the dispersion, mixing, and carbonization processes.

[0035] As a further improvement, the aforementioned The powder is pomegranate-shaped with a particle size of 0.8-1.2 micrometers.

[0036] Furthermore, the aforementioned The powder has a particle size of 1 micrometer.

[0037] Secondly, the present invention also provides the Zn-Fe-Mn oxide-hard carbon composite material, which is prepared by the preparation method of the Zn-Fe-Mn oxide-hard carbon composite material described in any one of the above claims.

[0038] Thirdly, the present invention also provides the application of the above-mentioned Zn-Fe-Mn oxide-hard carbon composite material, which is used as a microwave absorbing material in aircraft stealth, electromagnetic absorption, electromagnetic protection or microwave anechoic chambers.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] The Zn-Fe-Mn oxide-hard carbon composite material proposed in this invention features a three-dimensional interconnected network structure formed by Zn-Fe-Mn oxide particles within a hard carbon matrix. This unique composite structure effectively enhances interfacial polarization and multiple scattering mechanisms, significantly improving the material's electromagnetic wave absorption performance and broadening the effective absorption bandwidth. This composite material exhibits a minimum reflection loss of -59.4 dB and an effective absorption bandwidth ranging from 4.5 to 18 GHz, demonstrating excellent microwave absorption characteristics and promising broad application prospects in stealth technology and electromagnetic protection.

[0041] The preparation method of this invention employs a process route combining co-precipitation-calcination and resin carbonization, enabling the efficient preparation of Zn-Fe-Mn oxide-hard carbon composite materials. This method features a simple process flow, controllable cost, and high yield, effectively addressing the shortcomings of existing microwave absorbing materials in terms of structural design and preparation processes. By controlling the proportion of organometallic complexes and carbonization conditions, a series of composite materials with different electromagnetic properties can be obtained to meet diverse application needs. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 It is pomegranate-shaped SEM image of a sphere;

[0044] Figure 2 This is a SEM image of Zn-Fe-Mn oxide particles;

[0045] Figure 3This is a three-dimensional reflection loss spectrum of Zn-Fe-Mn oxide-hard carbon composite material Example 1;

[0046] Figure 4 This is the three-dimensional reflection loss spectrum of Example 2 of Zn-Fe-Mn oxide-hard carbon composite material;

[0047] Figure 5 This is the three-dimensional reflection loss spectrum of Example 3 of Zn-Fe-Mn oxide-hard carbon composite material;

[0048] Figure 6 This is the three-dimensional reflection loss spectrum of Example 4 of Zn-Fe-Mn oxide-hard carbon composite material;

[0049] Figure 7 This is the three-dimensional reflection loss spectrum of Example 5 of Zn-Fe-Mn oxide-hard carbon composite material;

[0050] Figure 8 This is the three-dimensional reflection loss spectrum of Example 6 of Zn-Fe-Mn oxide-hard carbon composite material;

[0051] Figure 9 This is the three-dimensional reflection loss spectrum of Example 7 of Zn-Fe-Mn oxide-hard carbon composite material;

[0052] Figure 10 This is the three-dimensional reflection loss spectrum of Example 8 of the Zn-Fe-Mn oxide-hard carbon composite material.

[0053] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0054] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention. Detailed Implementation

[0055] The present application will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present application.

[0056] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges or individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0057] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0058] Unless otherwise specified, all technical features and optional technical features of this invention can be combined to form new technical solutions.

[0059] In the context of this specification, including the following embodiments, the test was performed in the following manner:

[0060] Powder SEM image scanning

[0061] Take a small amount The powder was added to ethanol and ultrasonically dispersed for 5 minutes. The ultrasonically dispersed powder was then evenly sprinkled onto a sample holder coated with conductive adhesive. Excess powder was blown away, and the sample holder was fixed on the SEM sample stage. Vacuum was applied for detection. The parameters were set as follows: accelerating voltage 10 kV, working distance 5 mm, medium scanning speed, beam size 5 nm, secondary electron detector (SE), and image resolution [missing information]. Output and save the image.

[0062] SEM image scanning of Zn-Fe-Mn oxide-hard carbon composite material

[0063] Take a small amount of Zn-Fe-Mn oxide-hard carbon composite powder, add ethanol and ultrasonically disperse for 5 min. Sprinkle the ultrasonically dispersed powder evenly onto a sample holder coated with conductive adhesive, blow away excess powder, fix the sample holder on the SEM sample stage, and perform detection under vacuum. Set the parameters as follows: accelerating voltage 15 kV, working distance 5 mm, slow scanning speed, beam size 3 nm, secondary electron detector (SE), and image resolution [missing information]. The image is output and saved.

[0064] Three-dimensional reflection loss (RL) spectrum determination

[0065] The obtained Zn-Fe-Mn oxide-hard carbon composite material was pressed into a coaxial ring and prepared into samples with different thicknesses of 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, and 4 mm. The frequency range of the testing instrument was set to 2 GHz to 18 GHz. The samples were placed in the testing fixture and connected to a vector network analyzer to measure the reflection coefficient (S11) of the samples. Each sample was tested three times for each thickness and the average value was taken. The measured sample reflection coefficient data was used to calculate the reflection loss value using the formula RL=20log10|S11|. Using Origin data processing software, a three-dimensional reflection spectrum was plotted with frequency as the X-axis, sample thickness as the Y-axis, and reflection loss value as the Z-axis.

[0066] The following detailed description of this application is based on specific embodiments, but the implementation and protection of this invention are not limited thereto. The following embodiments are only some embodiments of this application and are not intended to limit this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0067] Example 1

[0068] Powder preparation

[0069] Zn(acac)₂ (2.1948 g), Mn(acac)₂ (4.9 g), Fe(acac)₂ (0.233 g), and 50 ml of NaHCO₃ solution (1.25 mol / L) were dissolved in 40 ml of water to undergo a coprecipitation reaction, resulting in a mixed-phase coprecipitate. This mixed-phase coprecipitate was then calcined at 750 °C under helium protection to obtain... The powder was examined using a scanning electron microscope (SEM). The powder was scanned to obtain SEM image of the sphere, results as follows Figure 1 As shown.

[0070] Preparation of Zn-Fe-Mn oxide-hard carbon composite materials

[0071] Take 10g The powder (particle size 0.8-1.2 μm) was dissolved in 120 mL of anhydrous ethanol and a homogeneous suspension was formed under mechanical stirring at 0.5 rpm. A 50 wt% self-made solvent mixture (mass ratio of carbon source, curing agent, organic solvent, and leavening agent 12:1:1:1) was slowly added at a rate of 0.05 mL / min using a syringe pump. Addition was stopped when the amount of the self-made solvent mixture reached 10 g (mass ratio of powder to self-made solvent mixture 1:1). The system was then heated to 60 °C and the stirring rate was increased to 100 rpm, maintained for 2 hours to complete the curing process. Finally, under argon protection, the temperature was increased to 800 °C at a rate of 5 °C / min for 2 hours to obtain a porous Zn-Fe-Mn oxide-hard carbon composite material, named M-HC-A1. The Zn-Fe-Mn oxide-hard carbon composite material was scanned using a scanning electron microscope (SEM), and SEM images of the Zn-Fe-Mn oxide-hard carbon composite material were obtained. The results are shown below. Figure 2 As shown. Simultaneously, the reflection loss value of the composite material was detected, and the three-dimensional reflection loss spectrum of the composite material is shown below. Figure 3 As shown.

[0072] Example 2

[0073] The difference is The raw material ratio used for the powder particles is A2 in Table 1. All other steps and parameters are the same as in Example 1, and the product is named M-HC-A2. The three-dimensional reflection loss spectrum of this composite material is shown below. Figure 4 As shown.

[0074] Example 3

[0075] The difference is The raw material ratio used for the powder particles was A3 in Table 1. All other steps and parameters were the same as in Example 1, and the product was named M-HC-A3. The three-dimensional reflection loss spectrum of this composite material is shown below. Figure 5 As shown.

[0076] Example 4

[0077] The difference is The raw material ratio used for the powder particles is A4 in Table 1. All other steps and parameters are the same as in Example 1, and the product is named M-HC-A4. The three-dimensional reflection loss spectrum of this composite material is shown below. Figure 6 As shown.

[0078] Example 5

[0079] The difference lies in the mass ratio of powder to self-made solvent, which is 1:3. All other steps and parameters are the same as in Example 1, and the product is named M-HC2-A1. The three-dimensional reflection loss spectrum of this composite material is shown below. Figure 7 As shown.

[0080] Example 6

[0081] The difference lies in the mass ratio of powder to self-made solvent, which is 1:6. All other steps and parameters are the same as in Example 1, and the product is named M-HC3-A1. The three-dimensional reflection loss spectrum of this composite material is shown below. Figure 8 As shown.

[0082] The products synthesized under four different raw material ratios (M-HC-A1, M-HC-A2, M-HC-A3, M-HC-A4, M-HC2-A1, and M-HC3-A1) were characterized and analyzed. Their microstructure was observed using scanning electron microscopy (SEM). The Zn-Fe-Mn oxide-hard carbon composite material was thoroughly mixed with paraffin wax, with the Zn-Fe-Mn oxide-hard carbon composite material content being 30%. The results showed that the samples synthesized under different conditions exhibited differences in microwave absorption performance, providing valuable data for further research on the performance optimization and application of Zn-Fe-Mn oxide-hard carbon composite materials.

[0083] Table 1 Parameters of Zn-Fe-Nn oxide-hard carbon composite materials

[0084]

[0085] according to Figures 3-8 As shown, the Zn-Fe-Mn oxide-hard carbon composite material exhibits excellent microwave absorption characteristics, with a minimum reflection loss of -59.4 dB. Experimental results indicate that by adjusting the amount of Fe(acac)3 added and the ratio of the self-made solvent combination, the microwave absorption performance of the material can be effectively optimized, broadening its effective absorption bandwidth to the 4.5-18 GHz range. Further analysis... Figures 3-8 This indicates that the changes in the content of Fe(acac)3 and the self-made solvent combination during the reaction and carbonization process significantly affect the distribution of magnetic components and the content of carbon matrix in the composite material, thereby regulating the electromagnetic parameters of the material and ultimately improving its microwave absorption performance.

[0086] Example 7

[0087] The difference lies in the mass ratio of carbon source, curing agent, organic solvent, and leavening agent in the self-made solvent combination: 12:1.5:1:1.5. All other steps and parameters are the same as in Example 1. The product is named M-HC4-A1. The three-dimensional reflection loss spectrum of this composite material is shown below. Figure 9 As shown.

[0088] Example 8

[0089] The difference lies in the mass ratio of carbon source, curing agent, organic solvent, and leavening agent in the self-made solvent combination: 12:0.5:1:0.5. All other steps and parameters are the same as in Example 1. The product is named M-HC4-A2. The three-dimensional reflection loss spectrum of this composite material is shown below. Figure 10 As shown.

[0090] according to Figures 9-10 As shown, adjusting the ratio of the self-made solvent combination can also regulate the microwave absorption performance of Zn-Fe-Mn oxide-hard carbon composite material, and achieve very good results. These research findings confirm that Zn-Fe-Mn oxide-hard carbon composite material has important application prospects and research value in the field of electromagnetic wave absorption.

[0091] 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 a Zn-Fe-Mn oxide-hard carbon composite material, characterized in that, Includes the following steps: Step a: Organometallic complexes of Zn, Mn, and Fe are prepared by co-precipitation-calcination method using organometallic complexes of Zn, Mn, and Fe, along with NaHCO3 powder. powder; Step b, will The powder was slowly added to the self-made solvent mixture and stirred until homogeneous, thus preparing the product. Mixed solutions; Step c: Increase the temperature and increase the stirring speed to fully solidify the mixed solution and obtain the solidified product; Step d: The cured product is subjected to high-temperature annealing under an inert atmosphere to obtain Zn-Fe-Mn oxide-hard carbon composite material. The organometallic complex of Zn is Zn(acac)2; the organometallic complex of Mn is Mn(acac)2; and the organometallic complex of Fe is Fe(acac)3. The self-made solvent combination includes a carbon source, a curing agent, an organic solvent, and a leavening agent; the carbon source includes at least one of phenolic resin and epoxy resin; the curing agent includes at least one of ethylenediamine and diethylenetriamine; the organic solvent includes at least one of anhydrous ethanol and acetone; and the leavening agent includes at least one of sodium bicarbonate and sodium carbonate. The stirring rate in step b is 0.1 rpm to 1.5 rpm, and the heating temperature in step c is 60℃ to 90℃, while the stirring rate is 100 rpm to 300 rpm.

2. The preparation method according to claim 1, characterized in that, The mass ratio of carbon source, curing agent, organic solvent and leavening agent is (10-15): (0.1-1): (0.5-5): (0.5-4).

3. The preparation method according to claim 2, characterized in that, The self-made solvent combination and the The mass ratio of the powder is (1-6): (1-6).

4. The preparation method according to claim 1, wherein the co-precipitation-calcination method in step a comprises the following steps: a-1: Dissolve the organometallic complexes of Zn, Mn, and Fe in sufficient deionized water to obtain a single solution; a-2: Mix all the single solutions obtained in a-1 to obtain a coprecipitate; a-3: Filter out the precipitate, wash it with deionized water 3-5 times, and then dry it. a-4: The coprecipitate was calcined under an inert gas atmosphere and then annealed at high temperature to obtain... powder.

5. The preparation method according to claim 4, characterized in that, The mass ratio of the Zn organometallic complex: Mn organometallic complex: Fe organometallic complex: NaHCO3 is 44:100:(1-60):

107.

6. The preparation method according to claim 5, characterized in that, In step a-3, the annealing temperature is 800℃~1000℃, the annealing time is 2-3 hours, and it is carried out under vacuum conditions.

7. A Zn-Fe-Mn oxide-hard carbon composite material, characterized in that, The Zn-Fe-Mn oxide-hard carbon composite material is prepared by the method for preparing Zn-Fe-Mn oxide-hard carbon composite material according to any one of claims 1-6.

8. An application of the Zn-Fe-Mn oxide-hard carbon composite material according to claim 7, characterized in that... The composite material can be used as a microwave absorbing material in scenarios such as aircraft stealth, electromagnetic absorption, electromagnetic protection, or microwave anechoic chambers.

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