Ternary FeNi-coated C / ZnO / CC composite material, preparation method and application thereof

Abstract

The invention relates to the field of high-performance fiber composite materials, and discloses a ternary FeNi-coated C / ZnO / CC composite material as well as a preparation method and application thereof. The material is formed by compounding a rod-like ZnO micron array and zero-dimensional FeNi-C nano particles on flexible carbon cloth. During preparation, the ZnO-coated CC flexible substrate is firstly prepared, then the FeNi-coated C nanoparticles are prepared through a vacuum arc method, and finally the ZnO-coated CC flexible substrate and the FeNi-coated C nanoparticles are compounded. The effective absorption bandwidth of the material can cover an X wave band (8-12 GHz), the minimum reflection loss reaches-39.36 dB, and the material can be used as a wave-absorbing and heat-conducting material. Compared with the prior art, the ZnO micron array is grown by the low-temperature solution method, so that a substrate is prevented from being damaged; znO provides a site to prevent FeNi-C agglomeration and enhance magnetic loss and impedance matching; the cross-scale layered multi-stage structure prolongs an electromagnetic wave scattering path and cooperates with magnetic and dielectric loss, so that the material has flexibility, thermal management and broadband wave-absorbing capability.

Description

Technical Field

[0001] The present invention belongs to high-performance fiber composite materials, and specifically relates to a ternary FeNi@C / ZnO / CC composite material, a preparation method and applications thereof. Background Art

[0002] With the rapid development of radar detection, wireless communication technology, and portable electronic products, various problems such as information transmission distortion, radiation pollution, and electromagnetic interference between adjacent lines have become increasingly prominent. The development of high-efficiency electromagnetic wave absorbing materials is of great significance to my country's economic development and national defense security. Considering the continuous development of electronic products towards high integration, high frequency, and smart wearable devices, new demands are being placed on absorbing materials that are lightweight, heat-dissipating, and flexible. In recent years, various metal-based absorbing materials have been introduced, such as magnetic metals Fe / Co / Ni, FeCo alloys, FeSiAl powders, and ferrites, all of which have been extensively studied. Although these metals have high electromagnetic loss characteristics, their rigid structure, heavy size, and complex surface treatment processes make them difficult to adapt to the integration requirements of flexible circuits.

[0003] Carbon materials have attracted extensive research interest due to their advantages such as light weight, strong weather resistance, abundant raw materials, and controllable properties. In addition, carbon materials have a variety of electrical properties, such as insulating nanodiamonds, semiconducting carbon nanotubes, and conductive graphene, which are mainly related to the electronic structure of carbon materials. For example, the carbon atoms in nanodiamonds are sp 3 The carbon atoms that make up graphene are sp 2 Hybridization. By manipulating the electrical properties of carbon materials, dielectric loss can be optimized. As a typical carbon material, carbon fiber fabric, with its excellent mechanical flexibility and adjustable conductivity, has become an ideal substrate for the next generation of flexible absorbers. However, its single dielectric loss mechanism and impedance matching characteristics with electromagnetic waves result in insufficient low-frequency absorption performance.

[0004] Existing technologies mainly use two types of modification strategies to improve the microwave absorption performance of carbon fibers: one is to load magnetic metal media on the surface of carbon fibers to enhance the overall hysteresis loss, but there are problems such as easy oxidation of metal particles and poor interface bonding; the second is to grow semiconductor oxide arrays such as zinc oxide on a carbon substrate to improve impedance matching, but it faces the problem of limited microwave attenuation due to insufficient conductive loss. The industry has tried to synergistically improve broadband absorption performance through the magneto-electric coupling effect, but the regulation of multi-component heterogeneous interfaces remains a technical difficulty. There are also some obstacles in industrialization, such as poor process compatibility leading to a contradiction between high-temperature processes and the thermal stability of flexible substrates, low structural controllability resulting in uneven growth of dielectric components, and cost-effectiveness imbalance resulting in low raw material utilization. Summary of the Invention

[0005] Based on the above-mentioned shortcomings of the existing technology, the present invention provides a ternary FeNi@C / ZnO / CC composite material, a preparation method and its application, aiming to solve the problem that the existing technology is difficult to prepare a magnetic fiber composite material with flexibility, thermal management ability and broadband absorption ability.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A ternary FeNi@C / ZnO / CC composite material is provided, which is composed of rod-shaped ZnO micron arrays grown on flexible carbon cloth (CC) and zero-dimensional FeNi@C nanoparticles;

[0008] The diameter of the rod-shaped ZnO is 150 to 200 nm;

[0009] The zero-dimensional FeNi@C is distributed on the surface of the rod-shaped ZnO micron array.

[0010] By designing a three-dimensional hierarchical multi-level structure to achieve mutual synergy, FeNi@C is evenly distributed on the surface of the ZnO micron array, which not only hinders the agglomeration of magnetic particles but also effectively constructs a magnetic / thermal conductive network.

[0011] The present invention also provides a method for preparing a ternary FeNi@C / ZnO / CC composite material, comprising the following steps:

[0012] S1. Raw material pretreatment: 3K carbon cloth was selected as the flexible substrate and ultrasonically cleaned with ethanol and deionized water for 40 minutes, followed by acidification with 6 mol / L nitric acid solution for 30 minutes to obtain an activated carbon cloth substrate. A mixed gas of methane and hydrogen was prepared with a gas pressure ratio of 0.02 MPa:0.04 MPa, and the mixture was premixed for use.

[0013] S2. Preparation of FeNi@C nanoparticles: 500-mesh Fe micron powder and 500-mesh Ni micron powder were simultaneously placed in a vacuum arc furnace and repeatedly turned over and melted for 6 times to prepare FeNi alloy as anode target and pure graphite carbon rod as cathode. The arc furnace cavity was pumped to 10 -5 After the premixed reaction gas was introduced, the working current was set to 90A, and the target was evaporated by arc discharge for 30 minutes, and then passivated in 0.1MPa nitrogen. After the reaction was completed, FeNi@C nanoparticles were collected.

[0014] S3. Preparation of ZnO micron arrays: The pretreated carbon cloth was immersed in a 0.05M zinc acetate / DMF solution for 2 minutes and thermally cured at 200°C to form a seed layer. Subsequently, the carbon cloth was reacted in a mixture of 0.06M zinc nitrate solution and 25% ammonia water at 95°C for 1 hour to obtain a vertically grown ZnO micron array.

[0015] The large specific surface area of ​​the ZnO micron array can provide sufficient riveting points for the subsequent coating of FeNi@C nanoparticles;

[0016] S4. Preparation of ternary material FeNi@C / ZnO / CC: The FeNi@C nanoparticles prepared in step S2 were dispersed in DMF solvent, sonicated, and then loaded onto the surface of the ZnO / CC flexible substrate using a pneumatic spraying process. Finally, the ternary material FeNi@C / ZnO / CC was prepared by vacuum drying.

[0017] The preparation method of the ternary FeNi@C / ZnO / CC composite material is further preferred.

[0018] Preferably, in step S2, the zinc nitrate solution and ammonia water mixture system is prepared according to the following formula: 70 mL of deionized water is used as a solvent to prepare a zinc nitrate aqueous solution with a concentration of 0.1 mol / L, and then 10 mL of ammonia water with a mass fraction of 25% to 30% is added dropwise to the above zinc nitrate solution, and the mixture is fully ultrasonicated for 20 minutes.

[0019] Preferably, the mass fraction ratio of the Fe micron powder to the Ni micron powder in step S2 is 4:6.

[0020] Preferably, in step S4, the FeNi@C nanoparticles prepared in step S2 are dispersed in a DMF solvent, and the mass fraction of the nanoparticles in the FeNi@C / DMF composite solution is adjusted to be 10-30 wt%.

[0021] Preferably, in step S4, the ultrasonic time is 30 minutes.

[0022] Preferably, in step S4, the vacuum drying is performed at a heating temperature of 180° C. for 12 hours.

[0023] The present invention also provides an application of a ternary FeNi@C / ZnO / CC composite material as a wave-absorbing and thermally conductive material. The effective absorption bandwidth (reflection loss ≤ -10dB) of the FeNi@C / ZnO / CC ternary composite material can cover the entire X-band (8 to 12 GHz), and the minimum reflection loss can reach -39.36dB.

[0024] The beneficial effects of the present invention compared to the prior art are:

[0025] (1) The present invention adopts a low-temperature solution method to controllably grow a ZnO micron array structure on a flexible carbon fiber substrate, thereby avoiding damage to the substrate caused by a high-temperature heat treatment process and ensuring interface bonding strength.

[0026] (2) The ZnO micron array provides sufficient spatial sites for the coating of the magnetic loss component FeNi@C, effectively preventing the aggregation and stacking of magnetic particles, and ensuring the homogenization and stability of the structure. The introduction of magnetic FeNi@C can increase the overall magnetic loss intensity, improve the impedance matching characteristics of the absorbing material, and allow more incident electromagnetic waves to effectively enter the absorbing material for electromagnetic attenuation. A magnetic / thermal conductive network is constructed, giving the material good thermal management performance. The magnetic FeNi@C particles prepared by the vacuum arc method have controllable particle size, high purity and no impurities, and do not produce toxic or harmful byproducts.

[0027] (3) The present invention combines low-temperature water bath directional growth, arc in-situ carbon coating and continuous coating process to achieve a cross-scale hierarchical multi-layer construction of three-dimensional carbon fiber fabrics, one-dimensional ZnO micron arrays and zero-dimensional FeNi@C nanoparticles in three-dimensional space. On the one hand, it can extend the scattering path of electromagnetic waves within the structure and increase the attenuation probability of electromagnetic waves. On the other hand, it improves the synergistic effect of magnetic and dielectric loss, making up for the shortcomings of a single dielectric loss mechanism. Therefore, the cross-scale hierarchical multi-level ternary FeNi@C / ZnO / CC composite material has flexibility, thermal management capabilities and broadband wave absorption capabilities.

[0028] (4) Functional integration. Through the three-dimensional interpenetrating network design of FeNi@C (magnetic loss factor tanδμ=0.32) and ZnO array (dielectric loss factor tanδε=0.28), interface polarization and multiple scattering effects are generated, which broadens the effective absorption bandwidth by 210% compared with single-component materials. The unique structure gives the ternary composite material excellent self-cleaning properties. FeNi@C nanoparticles construct heat-conducting network channels, and broadband absorption is achieved by regulating coating parameters. This composite material with flexibility, thermal management capabilities and electromagnetic absorption characteristics shows the application advantages of multifunctional integration. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The preparation flow chart of the ternary material FeNi@C / ZnO / CC (abbreviated as CZF);

[0030] Figure 2 XRD patterns of prepared carbon cloth (CC), CC@ZnO and CZF;

[0031] Figure 3 Raman spectra of the prepared carbon cloth (CC), CC@ZnO, and CZF;

[0032] Figure 4Micromorphology characterization of the samples, (A) SEM image of pure CC, (B) SEM image of CC@ZnO, (C-E) SEM images of CZF1-CZF3, (F-I) magnified images of the corresponding areas, (J) element distribution map of CZF1;

[0033] Figure 5 XPS spectra of CZF1, (A) full spectrum, (B) C1s fine spectrum, (C) O1s fine spectrum, (D) Zn2p fine spectrum, (E) Fe2p fine spectrum, (F) Ni2p fine spectrum;

[0034] Figure 6 Physical performance characterization: (A, B) hysteresis loops, (C) resistance comparison of each sample, (D) flexible bending display of CZF1, (E) water drop angle, (F) schematic diagram of hydrophobic mechanism;

[0035] Figure 7 Wave absorption performance, (A-D) three-dimensional graphs of reflection loss, frequency, and thickness, (A1-D1) two-dimensional graphs of reflection loss, frequency, and thickness, (E) graph of minimum reflection and thickness, and (F) graph of effective bandwidth and thickness.

[0036] Figure 8 is the electromagnetic response capability, (A, B) real / imaginary part of complex permittivity, (D, E) real / imaginary part of complex magnetic permeability, (C) dielectric loss angle, (F) magnetic loss angle, (GI) Cole-Cole polarization curve;

[0037] Figure 9 Impedance matching characteristics, (A1-D1) relationship between input impedance Z and frequency, (A2-D2) relationship between impedance Δ and frequency, (E) electromagnetic wave loss mechanism diagram;

[0038] Figure 10 Thermal management performance test, (A) heating infrared image, (B) cooling infrared image, (C) heating curve, (D) cooling curve, (E) thermal conductivity comparison chart of each sample. DETAILED DESCRIPTION

[0039] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, the following detailed description of the specific embodiments of the present invention is given in conjunction with the following embodiments. The following is merely an example and illustration of the concept of the present invention. Those skilled in the art may make various modifications, additions, or substitute similar methods for the specific embodiments described. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they shall fall within the scope of protection of the present invention.

[0040] The above preparation method of the present invention is described below through specific examples and comparative examples.

[0041] Example 1

[0042] This embodiment provides a method for preparing a ternary FeNi@C / ZnO / CC composite material. Figure 1 A flow chart for preparation includes the following steps:

[0043] S1. Raw material pretreatment. A 3K carbon cloth substrate was selected as the flexible substrate and ultrasonically cleaned with ethanol and deionized water for 40 minutes, followed by acidification with a 6 mol / L nitric acid solution for 30 minutes to obtain an activated carbon cloth substrate. A methane and hydrogen gas mixture was prepared with a pressure ratio of 0.02 MPa:0.04 MPa and premixed for later use.

[0044] S2, FeNi@C nanoparticle preparation. According to the mass fraction, 40 parts of Fe micron powder with a particle size of 500 mesh and 60 parts of Ni micron powder with a particle size of 500 mesh were put into a vacuum arc furnace and repeatedly turned and melted 6 times to prepare FeNi alloy as anode target and pure graphite carbon rod as cathode. The arc furnace cavity was pumped to 10 -5 After Pa, the premixed reaction gas was introduced, and the working current was set to 90A. The target material was evaporated by arc discharge for 30 minutes and then passivated in 0.1MPa nitrogen. After the reaction was completed, FeNi@C nanoparticles were collected.

[0045] S3. Preparation of ZnO micron arrays. The pretreated carbon cloth was immersed in a 0.05M zinc acetate / DMF solution for 2 minutes and thermally cured at 200°C to form a seed layer. Subsequently, the carbon cloth was reacted in a mixture of 0.06M zinc nitrate solution and 25% ammonia water at 95°C for 1 hour to obtain vertically grown ZnO micron arrays.

[0046] S4. Preparation of the ternary FeNi@C / ZnO / CC material: The nanoparticles prepared in step S2 were dispersed in DMF solvent, with a FeNi@C mass fraction of 10 wt %. The solution was homogenized by ultrasonication for 30 minutes and then pneumatically sprayed onto a ZnO / CC flexible substrate. Finally, the ternary FeNi@C / ZnO / CC composite material was prepared by vacuum drying and heating at 180°C for 12 hours. This sample was labeled CZF1.

[0047] Example 2

[0048] This example provides a method for preparing a ternary FeNi@C / ZnO / CC composite material. This method differs from Example 1 only in that, in step S4, 20 wt% FeNi@C nanoparticles are dispersed in DMF solvent to produce the resulting ternary FeNi@C / ZnO / CC composite material. The final sample is labeled CZF2. This example investigates the effects of magnetic loss and impedance matching on electromagnetic performance by adjusting the FeNi@C loading.

[0049] Example 3

[0050] This embodiment provides a method for preparing a ternary FeNi@C / ZnO / CC composite material, which differs from Example 1 only in that FeNi@C nanoparticles are dispersed in DMF solvent at 30 wt % to obtain a FeNi@C / ZnO / CC composite material. The final sample is labeled CZF3.

[0051] Comparative Example 1

[0052] This comparative example provides a method for preparing an activated carbon cloth substrate (CC), which comprises the following steps:

[0053] S1. Raw material pretreatment: 3K carbon cloth was selected as a flexible substrate and ultrasonically cleaned with ethanol and deionized water for 40 minutes, followed by acidification with 6 mol / L nitric acid solution for 30 minutes to obtain an activated carbon cloth substrate.

[0054] Comparative Example 2

[0055] This comparative example provides a method for preparing a CC@ZnO composite material, which comprises the following steps:

[0056] S1. Raw material pretreatment. A 3K carbon cloth substrate was selected as the flexible substrate and ultrasonically cleaned with ethanol and deionized water for 40 minutes, followed by acidification with a 6 mol / L nitric acid solution for 30 minutes to obtain an activated carbon cloth substrate. A methane and hydrogen gas mixture was prepared with a pressure ratio of 0.02 MPa:0.04 MPa and premixed for later use.

[0057] S2, FeNi@C nanoparticle preparation. According to the mass fraction, 40 parts of Fe micron powder with a particle size of 500 mesh and 60 parts of Ni micron powder with a particle size of 500 mesh were put into a vacuum arc furnace and repeatedly turned and melted 6 times to prepare FeNi alloy as anode target and pure graphite carbon rod as cathode. The arc furnace cavity was pumped to 10 -5 After Pa, the premixed reaction gas was introduced, and the working current was set to 90A. The target material was evaporated by arc discharge for 30 minutes and then passivated in 0.1MPa nitrogen. After the reaction was completed, FeNi@C nanoparticles were collected.

[0058] S3. Preparation of ZnO micron arrays. The pretreated carbon cloth was immersed in a 0.05M zinc acetate / DMF solution for 2 minutes and thermally cured at 200°C to form a seed layer. Subsequently, the carbon cloth was reacted in a mixture of 0.06M zinc nitrate solution and 25% ammonia water at 95°C for 1 hour to obtain vertically grown ZnO micron arrays.

[0059] Test Example 1

[0060] This test example provides an XRD characterization of a ternary FeNi@C / ZnO / CC composite material:

[0061] In order to detect the crystal structure and phase composition of CC, CC@ZnO and CZF composite materials, the present invention adopts X-ray diffraction (XRD) testing method for analysis. Figure 2 As shown: All samples have characteristic peaks of graphite carbon (002) crystal plane at 26°~27°, confirming the existence of carbon cloth substrate; the diffraction peaks in the range of 31.7°~62.8° correspond to the typical crystal plane of hexagonal wurtzite ZnO 27; The diffraction peaks at 43.49°, 50.67°, and 74.54° match the (111), (200), and (220) crystal planes of cubic FeNi alloy (JCPDS#47-1417), indicating the successful introduction of FeNi alloy into CZF. No carbide or oxide impurities were detected, verifying the high purity of the material. These results confirm the effective composite of FeNi@C nanoparticles and ZnO micron arrays on carbon cloth via the pneumatic spraying process.

[0062] Test Example 2

[0063] This test example provides a Raman characterization of a ternary FeNi@C / ZnO / CC composite material:

[0064] The present invention uses Raman spectroscopy to analyze defects in carbon materials, such as Figure 3 As shown: CZF1, CZF2 and CZF3 samples at 1348.2 cm -1 (D belt) and 1595.5cm -1 There are characteristic peaks at (G band), corresponding to the intra-layer lattice defects of graphene and sp 2 E of hybrid carbon 2g Vibration mode. The intensity ratio of D band to G band (I D / I G ) increased from 0.82 (CZF1) to 0.98 (CZF3), indicating that the increase in the concentration of FeNi@C nanoparticles leads to an increase in the defect density of the carbon layer and a decrease in the degree of graphitization. -1 The 2D peak at 570 cm-1 becomes broad and its intensity weakens, indicating that the number of graphene layers increases with the increase of FeNi@C concentration, suggesting that the nanoparticles are aggregated.-1 The intensity of the faint ZnOA1(TO) peak at the FeNi@C nanorods decreases significantly with increasing FeNi@C loading, confirming that the ZnO nanorods are gradually covered by FeNi@C. Since the Raman detection depth is only approximately 10 nm, the signal originates primarily from the carbon components in the FeNi@C, rather than the carbon cloth substrate. These results reveal the regulatory effect of FeNi@C concentration on the material's defect structure, degree of graphitization, and surface coverage.

[0065] Test Example 3

[0066] This test example provides a SEM characterization of a ternary FeNi@C / ZnO / CC composite material:

[0067] The present invention adopts SEM to analyze the microscopic morphology of the sample. Figure 4 As shown in A, the surface of pure carbon cloth is smooth. The surface of carbon cloth activated by nitric acid forms rich oxygen-containing functional groups, which significantly improves the Zn 2+ The adsorption capacity of CC@ZnO samples can be observed to be in situ grown ZnO columnar arrays on the CC surface ( Figure 4 B). With the coating of FeNi@C, a three-dimensional hierarchical crown structure is formed ( Figure 4 C), the structure extends the electromagnetic wave scattering path through a high aspect ratio (>70) and an internal cavity, while exerting a steric hindrance effect to inhibit the aggregation of FeNi@C nanoparticles. As the FeNi@C spray concentration increases, the ZnO array is gradually covered to form a rough surface structure ( Figure 4 C~E), EDX confirmed that the Zn / Fe / Ni elements in sample CZF1 are uniformly distributed ( Figure 4 J).

[0068] Test Example 4

[0069] This test example provides an XPS characterization of a ternary FeNi@C / ZnO / CC composite material:

[0070] The present invention uses XPS to analyze the chemical bonding state of sample CZF1, such as Figure 5 As shown. Characteristic peaks with binding energies of 285eV (C1s), 501eV (Zn LMM), 534eV (O1s), 641eV (Ni LMM), and 710eV (Fe2p) were detected on the surface of sample CZF1, confirming that the material contains five elements: C, Zn, O, Ni, and Fe ( Figure 5 A). High-resolution fine spectrum analysis shows that: 1. C1s spectrum ( Figure 5 B) decomposed into two chemical bonding configurations at 284.6eV (C=C / CC) and 285.7eV (CO), indicating the presence of graphitized carbon and oxidized functional groups in the carbon structure; 2. O1s spectrum ( Figure 5C) shows a Zn-O-Zn characteristic peak at 530.61eV and an oxygen vacancy signal at 531.80eV, confirming the existence of ZnO lattice defects; 3. Zn2p spectrum ( Figure 5 The distance between the double peaks at 1021.8eV (Zn2p3 / 2) and 1044.9eV (Zn2p1 / 2) in D) is 23.1eV, which is consistent with the Zn 2+ Standard binding energy difference; 4. Fe2p spectrum ( Figure 5 E) The characteristic peaks of metallic iron are shown at 706.6 eV (Fe2p3 / 2) and 719.6 eV (Fe2p1 / 2). The peaks are symmetrical and there are no oxidation peaks, indicating that the Fe element exists in a stable metallic state. 5. The characteristic peaks at 852.3 eV (Ni2p3 / 2) and 869.6 eV (Ni2p1 / 2) in the Ni2p spectrum are 17.3 eV apart, which is consistent with the standard spectrum of metallic nickel.

[0071] Test Example 5

[0072] This test example provides a multifunctional performance characterization of a ternary FeNi@C / ZnO / CC composite material:

[0073] The present invention adopts VSM to test and analyze the magnetic properties of the sample, such as Figure 6 As shown in A and 6B: The saturation magnetization (Ms) of CZF1, CZF2, and CZF3 samples under an external magnetic field of 15kOe is 3.7, 8.6, and 13.2emu / g, respectively, showing typical ferromagnetic properties. According to the Stoner-Wohlfarth theory, the anisotropy field H is derived. eff =4K / (3μ0M s ) and the resonant frequency f γ =γ×H eff The relationship between the two shows that high M s The coercivity (H) of all samples c ) is maintained at 250Oe, confirming its positive correlation with the anisotropy constant. The contact angle (WCA) test shows that ( Figure 6 E): The water contact angle of the original carbon cloth is 117°. After being modified with FeNi@C, the WCA of CZF1 increases to 155°, reaching the superhydrophobic standard (WCA ≥ 150°). According to the Cassie-Baxter model, this property is derived from the following two aspects: a. The micron-scale roughness formed by the ZnO microarray; b. The nanoscale surface protrusion structure constructed by the FeNi@C nanoparticles ( Figure 6F). The electrical properties of the samples were tested using a four-probe technique. The results showed that the original carbon cloth had a resistance of 13.3±0.8Ω / sq, which increased to 15±1.5Ω / sq after ZnO growth modification. The FeNi@C coating reduced the overall resistance, with CZF3 having the lowest resistance, reaching 5.5±0.5Ω / sq ( Figure 6 C). This "first increase and then decrease" resistance change pattern proves that the double coating structure can accurately control the conductive network of carbon cloth. 4. The excellent flexibility and bendability of the modified material ( Figure 6 D), suitable for scenarios such as flexible electronic devices and electromagnetic shielding fabrics.

[0074] Test Example 6

[0075] This test example provides a microwave absorption performance test of a ternary FeNi@C / ZnO / CC composite material:

[0076] The present invention uses a vector network analyzer to detect the reflection loss (RL) based on transmission line theory, and uses the effective absorption bandwidth (EAB, RL < -10dB) and the minimum RL value as the evaluation indicators of the absorption performance. The minimum reflection loss value of pure carbon cloth is only -9.62dB, and the effective absorption bandwidth is 0GHz. The ZnO-modified sample CC@ZnO can achieve RL of -21.35dB and EAB of 4.1GHz when the thickness is 3.0mm. Figure 7 A and A1). This is mainly because the introduction of ZnO optimizes the overall impedance matching, allowing more electromagnetic waves to penetrate into the absorber. After coating with FeNi@C particles, the absorption performance shows a pattern of first increasing and then decreasing, such as Figure 7 As shown in B to D, the minimum RL of CZF1 is -39.36dB, and EAB is 5.8GHz. The minimum RL of sample CZF2 is -15.53dB, and EAB can cover the entire Ku band, reaching up to 6.3GHz. The minimum RL of sample CZF3 is further weakened, only -10.53dB, and EAB reaches 4.9GHz. Through the comparison analysis of the thickness-frequency two-dimensional spectrum ( Figure 7 A1~D1), it cannot be seen that the CZF sample can achieve 4.1~6.3GHz broadband absorption in an ultra-thin thickness of 1.0~3.0mm, meeting the "thin, light, wide and strong" requirements of flexible devices. Figure 7 E and 7F further compare the minimum RL and EAB of each sample. It can be seen that the coating of low-concentration magnetic particles can effectively improve the overall absorption performance.

[0077] Test Example 7

[0078] This test example provides a characterization of the electromagnetic response performance of a ternary FeNi@C / ZnO / CC composite material:

[0079] The present invention uses the complex dielectric constant and magnetic permeability in the range of 2 to 18 GHz to evaluate the electromagnetic response performance of the sample. Figure 8 As shown in Figure A, the real part of the complex dielectric constant (ε') of each sample shows a downward trend, which is consistent with the typical dielectric dispersion effect of carbon-based materials. The ε' value of the ternary material CZF changes with the coating concentration of FeNi@C. The initial values ​​of ε' of CZF1 to CZF3 are 8.19 / 11.21 / 13.29, respectively, and decrease to 1.40 / 0.99 / 1.42 ( Figure 8 B). This phenomenon is attributed to the following: (1) the semiconductor properties of ZnO suppress the conduction loss, making the ε" of CC@ZnO stable at about 0.95; (2) FeNi@C particles construct a three-dimensional conductive network, and its dielectric imaginary part ε" is positively correlated with the conductivity (in line with the theory of σ=2πfε0ε"); (3) the ZnO / CC heterojunction forms a "microcapacitor" structure, which enhances the interface polarization effect through charge accumulation. The complex magnetic permeability results show that the μ' value of the CZF sample increases below 12.32 GHz, decreases rapidly from 14.90 to 18 GHz, and has magnetic resonance peaks at 15.03 GHz (CZF1), 13.66 GHz (CZF2), and 12.32 GHz (CZF3). Figure 8 D and E). The magnetic loss mechanism is as follows: (1) the C0 value is constant in the 6-12 GHz frequency range, confirming that eddy current loss is dominant; (2) the resonance peak above 10 GHz conforms to the exchange resonance effect of Aharonov's law; (3) the increase of FeNi@C content significantly increases the μ' value, which is consistent with the M measured by VSM. s The values ​​are positively correlated. Through the comprehensive analysis of Cole-Cole curve and Debye model ( Figure 8 G~I), it can be found that there are three polarization mechanisms in the CZF sample: (1) interfacial polarization caused by charge accumulation at the ZnO / CC heterojunction interface; (2) dipole polarization formed by carbon shell defects of FeNi@C particles; and (3) heterostructure relaxation polarization between ZnO and FeNi@C materials.

[0080] Test Example 8

[0081] This test example provides a characterization of the impedance matching and attenuation performance of a ternary FeNi@C / ZnO / CC composite material:

[0082] The present invention adopts the impedance matching factor Z (Z = Z in / Z0) to evaluate the impedance matching characteristics of each sample, such as Figure 9As shown in A1 to D1: Sample CC@ZnO achieves Z≤1 in the 7.75-18 GHz frequency band, indicating optimal impedance matching. The matching range of CZF1 is reduced to 13.70-8 GHz, while CZF2 / CZF3 have no matching region, confirming that excessive loading of FeNi@C can lead to enhanced interface reflection. The impedance deviation is further quantified using the triangular curve Δ=|sinh2(kfd)-M|, which is given by Figure 9 From A2 to D2, it can be seen that CC@ZnO has the smallest Δ area (<1.0), verifying its optimal impedance adaptability with free space. Figure 9 E summarizes the multiple magnetic / dielectric loss mechanisms of the ternary material CZF, which mainly include: (1) heterogeneous interface polarization (charge accumulation at the FeNi@C / ZnO / CC interface); (2) conductive network loss (three-dimensional conductive path formed by FeNi@C); and (3) magnetic loss composed of low-frequency eddy current loss and high-frequency exchange resonance.

[0083] Test Example 9

[0084] This test example provides a characterization of the thermal management performance of a ternary FeNi@C / ZnO / CC composite material: the present invention places the experimental sample on a constant temperature hot plate (80°C) and records the temperature change of each sample using an infrared thermometer. P1 to P5 correspond to samples CC, CC@ZnO, and CZF1 to CZF3, respectively. Figure 10 It can be found that the temperature of CZF3 changes the fastest, and all samples reach the temperature saturation state within 50 seconds ( Figure 10 A and 10C). The cooling test is to heat the samples to 80℃, transfer them to the room temperature test bench, and use an infrared thermometer to record the temperature changes of each sample, such as Figure 10 As shown in B and D, CZF2 has the fastest cooling rate, which is about 40% higher than pure CC. Figure 10 E): The thermal conductivity of pure CC is 0.058Wm -1 K -1 The introduction of ZnO leads to a decrease in thermal conductivity (CC@ZnO: 0.041Wm -1 K -1 1). With the coating of FeNi@C nanoparticles, the thermal conductivity of CZF3 is significantly improved, reaching 0.23Wm -1 K -1 , which is 3.96 times that of pure CC. This is mainly related to the three-dimensional continuous thermal conductive network formed by the alloy nanoparticles.

Claims

1. A ternary FeNi@C / ZnO / CC composite material, characterized in that: The composite material is composed of rod-shaped ZnO micron arrays grown on flexible carbon cloth and zero-dimensional FeNi@C nanoparticles; The diameter of the rod-shaped ZnO is 150 to 200 nm; The zero-dimensional FeNi@C is distributed on the surface of the rod-shaped ZnO micron array.

2. A method for preparing the ternary FeNi@C / ZnO / CC composite material according to claim 1, characterized in that: The preparation method comprises the following steps: S1. Raw material pretreatment: 3K carbon cloth was selected as the flexible substrate and ultrasonically cleaned with ethanol and deionized water for 40 minutes, followed by acidification with 6 mol / L nitric acid solution for 30 minutes to obtain an activated carbon cloth substrate. A mixed gas of methane and hydrogen was prepared with a gas pressure ratio of 0.02 MPa:0.04 MPa, and the mixture was premixed for use. S2. Preparation of FeNi@C nanoparticles: 500-mesh Fe micron powder and 500-mesh Ni micron powder were simultaneously placed in a vacuum arc furnace and repeatedly turned over and melted for 6 times to prepare FeNi alloy as anode target and pure graphite carbon rod as cathode. The arc furnace cavity was pumped to 10 -5 After the target material is evaporating at 30 min, the target is passivated in 0.1 MPa nitrogen atmosphere. After the reaction is completed, FeNi@C nanoparticles are collected. S3. Preparation of ZnO micron arrays: The pretreated carbon cloth was immersed in a 0.05M zinc acetate / DMF solution for 2 minutes and thermally cured at 200°C to form a seed layer. Subsequently, the carbon cloth was reacted in a mixture of 0.06M zinc nitrate solution and 25% ammonia water at 95°C for 1 hour to obtain a vertically grown ZnO micron array. S4. Preparation of ternary material FeNi@C / ZnO / CC: The FeNi@C nanoparticles prepared in step S2 were dispersed in DMF solvent, sonicated, and then loaded onto the surface of the ZnO / CC flexible substrate using a pneumatic spraying process. Finally, the ternary material FeNi@C / ZnO / CC was prepared by vacuum drying.

3. The method for preparing the ternary FeNi@C / ZnO / CC composite material according to claim 2, characterized in that: In step S2, the zinc nitrate solution and ammonia water mixture system is prepared according to the following formula: 70 mL of deionized water is used as a solvent to prepare a zinc nitrate aqueous solution with a concentration of 0.1 mol / L, and then 10 mL of ammonia water with a mass fraction of 25% to 30% is added dropwise to the above zinc nitrate solution, and the mixture is fully ultrasonicated for 20 minutes.

4. The method for preparing the ternary FeNi@C / ZnO / CC composite material according to claim 2, characterized in that: The mass fraction ratio of the Fe micron powder to the Ni micron powder in step S2 is 4:

6.

5. The method for preparing the ternary FeNi@C / ZnO / CC composite material according to claim 2, characterized in that: In step S4, the FeNi@C nanoparticles prepared in step S2 are dispersed in a DMF solvent, and the mass fraction of the nanoparticles in the FeNi@C / DMF composite solution is adjusted to be 10-30 wt%.

6. The method for preparing the ternary FeNi@C / ZnO / CC composite material according to claim 2, characterized in that: In step S4, the ultrasonic time is 30 minutes.

7. The method for preparing the ternary FeNi@C / ZnO / CC composite material according to claim 2, characterized in that: In step S4, the heating temperature of the vacuum drying is 180° C., and the heating time is 12 h.

8. Use of the ternary FeNi@C / ZnO / CC composite material according to claims 1 to 7 as a wave absorbing and thermal conductive material, characterized in that: The effective absorption bandwidth (reflection loss ≤ -10dB) of the FeNi@C / ZnO / CC ternary composite material can cover the entire X-band (8 to 12GHz), and the minimum reflection loss can reach -39.36dB.

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