A dual-magnetic metal-carbon nanocomposite wave-absorbing material and a preparation method thereof

Abstract

This invention belongs to the field of functional materials and electromagnetic wave absorbing materials, specifically disclosing a bimagnetic metal-carbon nanocomposite microwave absorbing material and its preparation method. Using a bimetallic Prussian blue analogue as a precursor, this invention prepares the bimagnetic metal-carbon nanocomposite microwave absorbing material through Joule heating treatment. Addressing the problems of easy agglomeration of metal particles, limited interface quantity, and complex preparation processes in existing technologies, this invention employs Joule heating technology to effectively inhibit the agglomeration and growth of metal nanoparticles at high temperatures, ensuring uniform dispersion of metal nanoparticles within a carbon matrix and forming abundant heterogeneous interfaces. The preparation method of this invention is simple, has a short cycle time, and low cost. The prepared material exhibits small metal particle size and abundant interface structures, demonstrating excellent microwave absorption performance in the 2-18 GHz frequency range, with a minimum reflection loss of -49.82 dB and an effective absorption bandwidth exceeding 7.0 GHz.

Description

Technical Field

[0001] This invention relates to the field of functional materials and electromagnetic wave absorbing materials, specifically to a method for preparing a dual-magnetic metal-carbon nanocomposite material and its application in microwave absorption. Background Technology

[0002] With the development of wireless communication, radar detection, and the high-speed and integrated nature of electronic devices, the electromagnetic environment is becoming increasingly complex, and electromagnetic wave leakage and electromagnetic interference are becoming more prominent, becoming key factors affecting equipment performance, safety, and information reliability. To suppress unnecessary electromagnetic radiation, the development of functional materials with high-efficiency absorption properties has become a current research hotspot. Among them, metal / carbon-based composite absorbing materials with tunable structures and rich loss mechanisms have received widespread attention and research. However, single-type materials often struggle to simultaneously possess comprehensive properties such as lightweight, strong absorption, wide bandwidth, and good stability. For example, metals or magnetic particles have high magnetic loss but high density, are prone to aggregation, and have poor corrosion resistance; carbon materials (such as carbon nanotubes and graphene) are lightweight, have high specific surface area, and good conductivity, but their dielectric loss is singular, easily leading to poor impedance matching.

[0003] To overcome the aforementioned limitations, composite design has gradually become a key strategy for improving microwave absorption performance. By combining magnetic metals with carbon materials, not only can the synergistic effect of dielectric and magnetic losses be achieved, but the microwave absorption capability can also be significantly improved through mechanisms such as interface polarization, electron transfer, and multiple scattering. In particular, the introduction of bimagnetic metals can further optimize the magnetic response behavior, enabling the composite material to exhibit superior microwave absorption performance across multiple frequency bands. However, existing preparation methods still suffer from problems such as complex processes, severe metal agglomeration, limited number of interfaces, and poor material stability, which restrict their practical applications.

[0004] Therefore, developing a structurally controllable, interface-stable, and uniformly dispersed dual-magnetic metal-carbon nanocomposite material, and proposing a simple and efficient preparation process, is of great significance for realizing lightweight, high-efficiency broadband microwave absorbing materials. This invention addresses the aforementioned shortcomings of existing technologies by proposing corresponding improvement methods and application schemes. Summary of the Invention

[0005] To address the aforementioned shortcomings of existing technologies, this invention provides a method for preparing a dual-magnetic metal-carbon nanocomposite microwave absorbing material. This method is not only simple to prepare, has a short production cycle, and is inexpensive, but also produces a dual-magnetic metal-carbon nanocomposite microwave absorbing material with a low metal particle size and abundant interfaces, exhibiting excellent microwave absorption performance.

[0006] To achieve the above objectives, the present invention employs the following technical solution: a method for preparing a dual-magnetic metal-carbon nanocomposite microwave absorbing material, comprising the following steps: A bimagnetic metal-carbon nanocomposite microwave absorbing material was prepared by calcining a bimagnetic metal-Prussian blue analogue in a Joule furnace at a temperature of 750-1100℃ for 2-10 s.

[0007] Further improvements to the preparation method of dual-magnetic metal-carbon nanocomposite microwave absorbing materials: Preferably, the calcination is performed using high-purity argon as a protective gas, and the flow rate of the argon is 10–500 mL / min.

[0008] Preferably, the manufacturer of the dual-magnetic metallic Prussian blue analogue is Jiangsu Xianfeng Nanomaterials Technology Co., Ltd., with model number XFJ103-8 and particle size of 100-400nm.

[0009] Preferably, the method for preparing the dual-magnetic metallic Prussian blue analogue is as follows: Step A: Dissolve the metal ion source and complexing agent in deionized water to form solution 1; dissolve potassium ferricyanide in deionized water to form solution 2; Step B: Mix and stir solutions 1 and 2, allow to stand to separate the precipitate, wash and dry to obtain a bimagnetic metal Prussian blue analogue.

[0010] Preferably, the molar ratio of the metal ion source to the complexing agent in solution 1 is 1:(1~3), and the molar concentration is 1~40 mmol / L.

[0011] Preferably, the molar concentration of potassium ferricyanide in solution 2 is 1~40 mmol / L.

[0012] Preferably, solutions 1 and 2 are mixed in equal volumes, and the molar ratio of the metal ion source contained in solution 1 to the potassium ferricyanide contained in solution 2 is (1~1.5):1.

[0013] Preferably, in step A, the metal ion source is a cobalt source or a nickel source, and the complexing agent is sodium citrate dihydrate.

[0014] Preferably, in step B, the settling time is 12 to 48 hours.

[0015] The second objective of this invention is to provide a method for preparing a dual-magnetic metal-carbon nanocomposite microwave absorbing material as described in any one of the above-mentioned methods.

[0016] The advantages of this invention compared to the prior art are as follows: This invention provides a method for preparing a bimagnetic metal-carbon nanocomposite microwave absorbing material. First, a bimagnetic metal Prussian blue analogue is prepared via a liquid-phase method. Then, using the bimagnetic Prussian blue analogue as a precursor, the bimagnetic metal-carbon nanocomposite microwave absorbing material is obtained after a simple Joule heating treatment. This composite microwave absorbing agent exhibits excellent microwave absorption performance due to its small metal particle size and abundant interfaces. Furthermore, the preparation process is simple, has a short preparation cycle, is low in cost, and is suitable for mass production, making it ideal for use as a high-efficiency microwave absorbing agent. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 The XRD patterns of the products prepared in Examples 1, 2, 3, 4, and 5 are obtained by using an X-ray diffraction analyzer for phase detection.

[0019] Figure 2 The morphology of the dual-magnetic metal-carbon nanocomposite absorbing materials prepared in Examples 1, 2, 3, 4, and 5 of this invention was examined using a scanning electron microscope at a magnification of 100k, and the resulting scanning electron microscope images were obtained.

[0020] Figure 3 The absorption performance diagrams are obtained by testing and calculating the electromagnetic parameters of the products prepared in Examples 1, 2, 3, 4, and 5 of this invention using a network vector analyzer. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0022] Preparation Example This preparation example provides a method for preparing a dual-magnetic metallic Prussian blue analogue, the specific steps of which are as follows: Step A: Dissolve 2.32g of nickel nitrate hexahydrate and 2.36g of sodium citrate dihydrate in 200mL of deionized water to a concentration of 40 mmol / L, forming solution 1. Dissolve 2.64g of potassium ferricyanide in 200mL of deionized water to a concentration of 40 mmol / L, forming solution 2. The molar ratio of nickel nitrate hexahydrate in solution 1 to potassium ferricyanide in solution 2 is 1:1.

[0023] Step B: Mix and stir solutions 1 and 2 for 10 min, let stand for 24 h, centrifuge to separate the precipitate, wash with deionized water 3 times, and then put it in an oven to dry at 80℃ for 24 h to obtain a bimagnetic metallo-Prussian blue analogue.

[0024] Tests showed that the particle size of the prepared dual-magnetic Prussian blue analogue was 100-400 nm.

[0025] Example 1 This embodiment provides a method for preparing a dual-magnetic metal-carbon nanocomposite microwave absorbing material, the steps of which are as follows: The bimagnetic metal Prussian blue analogue prepared in the preparation example was placed in a Joule furnace for calcination. Argon was used as a protective gas during the calcination process. The flow rate of argon was 100 mL / min, the calcination temperature was 750 °C, and the calcination time was 2 s, thus obtaining a bimagnetic metal-carbon nanocomposite microwave absorbing material.

[0026] Example 2 This embodiment provides a method for preparing a dual-magnetic metal-carbon nanocomposite microwave absorbing material, the steps of which are as follows: The bimagnetic metal Prussian blue analogue prepared in the preparation example was placed in a Joule furnace for calcination. Argon was used as a protective gas during the calcination process. The flow rate of argon was 100 mL / min, the calcination temperature was 800℃, and the calcination time was 4 s, thus obtaining a bimagnetic metal-carbon nanocomposite microwave absorbing material.

[0027] Example 3 This embodiment provides a method for preparing a dual-magnetic metal-carbon nanocomposite microwave absorbing material, the steps of which are as follows: The bimagnetic metal Prussian blue analogue prepared in the preparation example was placed in a Joule furnace for calcination. Argon was used as a protective gas during the calcination process. The flow rate of argon was 10 mL / min, the calcination temperature was 900℃, and the calcination time was 4 s, thus obtaining a bimagnetic metal-carbon nanocomposite microwave absorbing material.

[0028] Example 4 This embodiment provides a method for preparing a dual-magnetic metal-carbon nanocomposite microwave absorbing material, the steps of which are as follows: A bimagnetic metal-carbon nanocomposite microwave absorbing material was prepared by calcining a bimagnetic metal-carbon nanocomposite material in a Joule furnace using argon as a protective gas at a flow rate of 10 mL / min, a calcination temperature of 1000℃, and a calcination time of 10 s.

[0029] Example 5 This embodiment provides a method for preparing a dual-magnetic metal-carbon nanocomposite microwave absorbing material, the steps of which are as follows: A bimagnetic metal-carbon nanocomposite microwave absorbing material was prepared by calcining a bimagnetic metal-carbon nanocomposite material in a Joule furnace using argon as a protective gas at a flow rate of 500 mL / min, a calcination temperature of 1100℃, and a calcination time of 10 s.

[0030] Phase detection, morphology observation and microwave absorption performance testing The phase composition and morphology of the dual-magnetic metal-carbon nanocomposite microwave absorbing materials prepared in Examples 1, 2, 3, 4, and 5 of this invention were analyzed, and the following results were obtained: (1) The products prepared in Examples 1, 2, 3, 4, and 5 of this invention were subjected to phase analysis using an X-ray diffraction analyzer, and the results were as follows: Figure 1 The X-ray diffraction pattern shown is from... Figure 1 It can be seen that the phases of the products obtained in Examples 1, 2, 3, 4, and 5 of this invention are mainly NiFe alloys with a face-centered cubic structure. In the XRD patterns, the peak intensity gradually increases with the calcination temperature, which is because the higher the calcination temperature, the higher the crystallinity of the NiFe alloy. In addition, the products should also contain a large amount of amorphous carbon, but there is no obvious signal in the XRD patterns.

[0031] (2) The morphology of the products obtained in Examples 1, 2, 3, 4, and 5 of this invention was examined using a scanning electron microscope, and the results were as follows: Figure 2The images shown are scanning electron microscope (SEM) images. Specifically, a is an FESEM image of the product obtained in Example 1 of this invention at 100k magnification; b is an FESEM image of the product obtained in Example 2 of this invention at 100k magnification; c is an FESEM image of the product obtained in Example 3 of this invention at 100k magnification; d is an FESEM image of the product obtained in Example 4 of this invention at 100k magnification; and e is an FESEM image of the product obtained in Example 5 of this invention at 100k magnification. Figure 2 As can be seen, in the dual-magnetic metal-carbon nanocomposite microwave absorbing materials prepared in Examples 1, 2, 3, 4 and 5 of the present invention, the NiFe alloy is spherical with a particle size of about 10~50nm, and the NiFe alloy nanospheres are attached to the carbon matrix.

[0032] (3) Electromagnetic parameters of the products obtained in Examples 1, 2, 3, 4, and 5 of this invention were tested using a network vector analyzer, and the results were calculated as follows: Figure 3 The absorption performance diagrams shown are as follows: a) is the absorption performance diagram of the product obtained in Example 1 of this invention; b) is the absorption performance diagram of the product obtained in Example 2 of this invention; c) is the absorption performance diagram of the product obtained in Example 3 of this invention; d) is the absorption performance diagram of the product prepared in Example 4 of this invention; and e) is the absorption performance diagram of the product obtained in Example 5 of this invention. Figure 3It can be seen that the dual-magnetic metal-carbon nanocomposite absorbing material prepared in Example 1 of this invention exhibits strong absorption performance in the 2-18 GHz frequency range, and shows the lowest reflection loss at a thickness of 1.7 mm, with a minimum reflection loss of -26.13 dB and an effective absorption bandwidth of 4.22 GHz. The dual-magnetic metal-carbon nanocomposite absorbing material prepared in Example 2 of this invention also exhibits strong absorption performance in the 2-18 GHz frequency range, and shows the lowest reflection loss at a thickness of 6.2 mm, with a minimum reflection loss as low as -27.6 dB and an effective absorption bandwidth of 2.63 GHz. The dual-magnetic metal-carbon nanocomposite absorbing material prepared in Example 3 of this invention also exhibits strong absorption performance in the 2-18 GHz frequency range, and shows the lowest reflection loss at a thickness of 8.9 mm, with a minimum reflection loss as low as -29.79 dB and an effective absorption bandwidth of 2.15 GHz. The dual-magnetic metal-carbon nanocomposite absorbing material prepared in Example 4 of this invention also exhibits strong absorption performance in the 2-18 GHz frequency range, showing the lowest reflection loss at a thickness of 2.9 mm, with a minimum reflection loss as low as -49.82 dB and an effective absorption bandwidth of 7.0 GHz. The dual-magnetic metal-carbon nanocomposite absorbing material prepared in Example 5 of this invention also exhibits strong absorption performance in the 2-18 GHz frequency range, showing the lowest reflection loss at a thickness of 2.6 mm, with a minimum reflection loss as low as -37.99 dB and an effective absorption bandwidth of 5.65 GHz. The dual-magnetic metal-carbon nanocomposite absorbing materials prepared in Examples 1, 2, 3, 4, and 5 of this invention exhibit excellent absorption performance. Those skilled in the art will understand that other dual-magnetic metal carbon nanocomposite absorbing materials also possess excellent absorption performance.

[0033] In summary, the method for preparing dual-magnetic metal-carbon nanocomposite microwave absorbing materials according to the embodiments of the present invention is not only simple in preparation process, short in production cycle and low in cost, but also produces materials with low metal particle size and rich interfaces, exhibiting good microwave absorption performance.

[0034] Those skilled in the art should understand that the above descriptions are merely several specific embodiments of the present invention, and not all embodiments. It should be noted that many modifications and improvements can be made by those skilled in the art, and all modifications or improvements not exceeding the scope of the claims should be considered within the protection scope of the present invention.

Claims

1. A method for preparing a dual-magnetic metal-carbon nanocomposite microwave absorbing material, characterized in that, Includes the following steps: A bimagnetic metal-carbon nanocomposite microwave absorbing material was prepared by calcining a bimagnetic metal-Prussian blue analogue in a Joule furnace at a temperature of 750-1100℃ for 2-10 s.

2. The preparation method of the dual-magnetic metal-carbon nanocomposite microwave absorbing material according to claim 1, characterized in that, The calcination process uses high-purity argon as a protective gas, with an argon flow rate of 10–500 mL / min.

3. The preparation method of the dual-magnetic metal-carbon nanocomposite microwave absorbing material according to claim 1, characterized in that, The manufacturer of the bimagnetic Prussian blue analogue is Jiangsu Xianfeng Nanomaterials Technology Co., Ltd., model number XFJ103-8, with a particle size of 100-400nm.

4. The preparation method of the dual-magnetic metal-carbon nanocomposite microwave absorbing material according to claim 1, characterized in that, The preparation method of the bimagnetic metallic Prussian blue analogue is as follows: Step A: Dissolve the metal ion source and complexing agent in deionized water to form solution 1; dissolve potassium ferricyanide in deionized water to form solution 2; Step B: Mix and stir solutions 1 and 2, allow to stand to separate the precipitate, wash and dry to obtain a bimagnetic metal Prussian blue analogue.

5. The preparation method of the dual-magnetic metal-carbon nanocomposite microwave absorbing material according to claim 4, characterized in that, The molar ratio of the metal ion source to the complexing agent in solution 1 is 1:(1~3), and the molar concentration is 1~40 mmol / L.

6. The method for preparing the dual-magnetic metal-carbon nanocomposite microwave absorbing material according to claim 4, characterized in that, The molar concentration of potassium ferricyanide in solution 2 is 1~40 mmol / L.

7. The method for preparing the dual-magnetic metal-carbon nanocomposite microwave absorbing material according to claim 4, 5, or 6, characterized in that, Equal volumes of solutions 1 and 2 are mixed. The molar ratio of the metal ion source in solution 1 to the potassium ferricyanide in solution 2 is (1~1.5):

1.

8. The method for preparing the dual-magnetic metal-carbon nanocomposite microwave absorbing material according to claim 4, characterized in that, In step A, the metal ion source is a cobalt source or a nickel source, and the complexing agent is sodium citrate dihydrate.

9. The method for preparing the dual-magnetic metal-carbon nanocomposite microwave absorbing material according to claim 4, characterized in that, In step B, the settling time is 12 to 48 hours.

10. A dual-magnetic metal-carbon nanocomposite microwave absorbing material prepared by the preparation method of the dual-magnetic metal-carbon nanocomposite microwave absorbing material according to any one of claims 1-9.

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