Method and materials for microwave-assisted rapid preparation of binary alloy high-efficiency microwave-absorbing materials

Abstract

The present invention discloses a method for rapidly preparing a binary alloy high-efficiency absorbing material using microwave assistance and the prepared absorbing material, comprising the following steps: (1) uniformly dispersing melamine in deionized water, and dispersing and dissolving cobalt nitrate hexahydrate in the above solution to form a precursor reaction solution A; (2) dispersing and dissolving dimethylimidazole in deionized water to form a solution B; (3) stirring and mixing solutions A and B and placing them in a microwave chemical reactor for solvent thermal reaction to obtain a composite precursor; (4) placing the obtained precursor and ferrocene in a tube furnace for heat treatment to obtain a hierarchical carbon-coated alloy final product. The prepared absorbing material has the characteristics of high electrical conductivity and high saturation magnetic intensity. The preparation method can achieve the advantages of large-scale, rapid preparation, simplicity, and good controllability of nano-absorbing materials, providing a reliable preparation method for high-efficiency electromagnetic wave absorbing materials.

Description

Technical Field

[0001] The present invention belongs to the field of preparation of novel magneto-electric synergistic nanometer wave-absorbing materials, in particular to a rapid preparation method of a carbon-based alloy composite wave-absorbing material with high saturation magnetic strength. Background Art

[0002] While current metal alloy absorbers can achieve strong absorption of high-frequency electromagnetic waves over a wide absorption bandwidth, they struggle to achieve strong absorption at low frequencies. Furthermore, the application environments of absorbers are becoming increasingly harsh, such as the high temperatures generated by high-speed flight and highly corrosive environments such as seawater and oil. Traditional alloy absorbers are susceptible to corrosion and oxidation, which poses serious challenges to their service life and absorbing performance. Developing alloy composite absorbers with excellent low-frequency electromagnetic wave absorption properties while also being resistant to oxidation and corrosion could significantly enhance their practical application in stealth materials for weaponry and equipment.

[0003] In this work, the researchers discovered a method for quickly preparing nano-carbon-based alloy composite absorbers with both high saturation magnetic strength and electrical conductivity. The basic unit of the prepared nano-absorbing composite material is composed of a carbon layer material and a metal alloy component. The one-dimensional nanotube layer is assembled into a three-dimensional nano-skeleton structure, and the alloy particles are confined to grow within the carbon layer. The nano-composite absorber exhibits characteristics such as high electrical conductivity, high saturation magnetic strength and resistance to environmental oxidation. At present, the main methods for preparing alloy absorbers are high-temperature smelting or chemical reduction, which mainly involves placing the metal source in a high-temperature smelting furnace or a reducing chemical solvent (such as hydrazine hydrate or sodium borohydride) to reduce the high-valent metal salt to a zero-valent alloy phase component. The above preparation method requires an extremely high-power heating couple for the hot melting reaction, or requires a large amount of environmentally polluting chemical reagents, which is not conducive to the low-cost and efficient preparation of functional materials. At the same time, this method is also difficult to achieve rapid and large-scale production of catalysts.

[0004] To address these issues, the present invention proposes a microwave-assisted rapid solvothermal reaction method. Using cobalt nitrate hexahydrate, dimethylimidazole, and melamine as raw materials, this method produces a carbon-based alloy high-efficiency microwave-absorbing composite material through a solvothermal reaction followed by high-temperature heat treatment in a hydrogen-argon mixed atmosphere. The experimental process is simple, enabling rapid, large-scale production of highly efficient electromagnetic wave absorbing and dissipating materials. Furthermore, the method is simple, reproducible, and cost-effective, providing a reliable sample preparation method for carbon-based alloy nanocomposites used in high-efficiency electromagnetic wave absorption. Summary of the Invention

[0005] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a method for quickly preparing a carbon-based alloy composite absorbing material with high saturation magnetic strength, which can be simply, efficiently and rapidly prepared in large quantities.

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

[0007] A microwave-assisted method for rapidly preparing a binary alloy high-efficiency microwave-absorbing material comprises the following steps:

[0008] (1) 400-600 mg of melamine was uniformly dispersed in 500 ml of deionized water, and 291 mg of cobalt nitrate hexahydrate was dispersed and dissolved in the above solution to form a precursor reaction solution A;

[0009] (2) 657 mg of dimethylimidazole was dispersed and dissolved in 500 ml of deionized water to form solution B;

[0010] (3) Solutions A and B are stirred and mixed and placed in a microwave chemical reactor for rapid solvothermal reaction to obtain a composite precursor;

[0011] (4) The obtained precursor and ferrocene are placed in a tube furnace at a mass ratio of 1:2.75 for heat treatment to obtain a hierarchical carbon-coated alloy final product.

[0012] As a preferred method, alloy absorbing materials with different saturation magnetic intensities are prepared by adjusting the heating power, heating time, heating rate of the tube furnace and mixed atmosphere ratio of the microwave chemical reactor in step (3).

[0013] As a preferred embodiment, the heating power of the microwave chemical reactor in step (3) is 700 watts.

[0014] As a preferred embodiment, the heating time of the microwave chemical reactor in step (3) is 300 seconds.

[0015] As a preferred embodiment, the heating rate of the tube furnace heat treatment in step (4) is 1.5 degrees Celsius per minute.

[0016] As a preferred embodiment, the tubular furnace heat treatment time in step (4) is 45 minutes.

[0017] As a preferred embodiment, the atmosphere condition for the heat treatment in the tubular furnace in step (4) is a hydrogen-argon mixture with a hydrogen content of 10%.

[0018] The present invention also provides a binary alloy high-efficiency absorbing material, which is prepared by the above method. The basic units of the binary alloy high-efficiency absorbing material are carbon layer material and metal alloy components, one-dimensional nanotube layers are assembled into a three-dimensional nano-skeleton structure, and cobalt-iron alloy particles grow in the carbon layer.

[0019] As described above, the present invention has the following beneficial effects: This method utilizes microwave-assisted solvothermal technology to promote the chemical reaction of cobalt nitrate and dimethylimidazole, which then undergoes a coordination reaction with the surface electrostatic adsorption of the polymeric melamine matrix, yielding melamine / ZIF-67. 500 mg of the precursor and 200 mg of ferrocene are heat-treated in a tube furnace in a hydrogen-argon mixed atmosphere to produce a carbon-based alloy composite absorber with high saturation magnetic strength. This method is simple, reproducible, and cost-effective, providing a reliable sample preparation method for the application of carbon-based alloy nanocomposites in high-efficiency electromagnetic wave absorption. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is an X-ray diffraction pattern of the carbon-based alloy composite absorbing material with high saturation magnetic strength prepared by the present invention;

[0021] Figure 2 The energy dispersion spectrum and element content of the carbon-based alloy composite absorbing material with high saturation magnetic strength prepared by the present invention;

[0022] Figure 3 This is a diagram of the wave absorption test performance of the carbon-based alloy composite wave absorbing material with high saturation magnetic strength prepared by the present invention. DETAILED DESCRIPTION

[0023] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0024] Example 1

[0025] Example 1 provides a microwave-assisted method for rapidly preparing a binary alloy high-efficiency microwave absorbing material, comprising the following steps:

[0026] (1) 400 mg of melamine was uniformly dispersed in 500 ml of deionized water, and 291 mg of cobalt nitrate hexahydrate was dispersed and dissolved in the above solution to form a precursor reaction solution A;

[0027] (2) 657 mg of dimethylimidazole was dispersed and dissolved in 500 ml of deionized water to form solution B;

[0028] (3) Solutions A and B were stirred and mixed and placed in a microwave chemical reactor for solvothermal reaction to obtain a composite precursor; the heating power of the microwave chemical reactor was 700 watts. The heating time of the microwave chemical reactor was 300 seconds. By adjusting the heating power and heating time of the microwave chemical reactor in step (3), the heating rate of the tubular furnace, and the ratio of the mixed atmosphere, alloy absorbing materials with different saturation magnetic intensities were prepared.

[0029] (4) The obtained precursor and ferrocene were placed in a tube furnace at a mass ratio of 1:2.75 and heat-treated to obtain a hierarchical carbon-coated alloy final product. The tube furnace heat treatment temperature was increased at a rate of 1.5 degrees Celsius per minute. The tube furnace heat treatment time was 45 minutes. The tube furnace heat treatment atmosphere was a hydrogen-argon mixture with a hydrogen content of 10%.

[0030] The basic units of the binary alloy high-efficiency wave-absorbing material are a carbon layer material and a metal alloy component. One-dimensional nanotube layers are assembled into a three-dimensional nano-skeleton structure, and cobalt-iron alloy particles grow in the carbon layer.

[0031] Example 2

[0032] Example 2 provides a microwave-assisted method for rapidly preparing a binary alloy high-efficiency microwave absorbing material, comprising the following steps:

[0033] (1) 600 mg of melamine was uniformly dispersed in 500 ml of deionized water, and 291 mg of cobalt nitrate hexahydrate was dispersed and dissolved in the above solution to form a precursor reaction solution A;

[0034] (2) 657 mg of dimethylimidazole was dispersed and dissolved in 500 ml of deionized water to form solution B;

[0035] (3) Solutions A and B were stirred and mixed and placed in a microwave chemical reactor for solvothermal reaction to obtain a composite precursor; the heating power of the microwave chemical reactor was 700 watts. The heating time of the microwave chemical reactor was 300 seconds. By adjusting the heating power and heating time of the microwave chemical reactor in step (3), the heating rate of the tubular furnace, and the ratio of the mixed atmosphere, alloy absorbing materials with different saturation magnetic intensities were prepared.

[0036] (4) The obtained precursor and ferrocene were placed in a tube furnace at a mass ratio of 1:2.75 and heat-treated to obtain a hierarchical carbon-coated alloy final product. The tube furnace heat treatment temperature was increased at a rate of 1.5 degrees Celsius per minute. The tube furnace heat treatment time was 45 minutes. The tube furnace heat treatment atmosphere was a hydrogen-argon mixture with a hydrogen content of 10%.

[0037] The basic units of the binary alloy high-efficiency wave-absorbing material are a carbon layer material and a metal alloy component. One-dimensional nanotube layers are assembled into a three-dimensional nano-skeleton structure, and cobalt-iron alloy particles grow in the carbon layer.

[0038] Example 3

[0039] Example 3 provides a microwave-assisted method for rapidly preparing a binary alloy high-efficiency microwave absorbing material, comprising the following steps:

[0040] (1) 500 mg of melamine was uniformly dispersed in 500 ml of deionized water, and 291 mg of cobalt nitrate hexahydrate was dispersed and dissolved in the above solution to form a precursor reaction solution A;

[0041] (2) 657 mg of dimethylimidazole was dispersed and dissolved in 500 ml of deionized water to form solution B;

[0042] (3) Solutions A and B were stirred and mixed and placed in a microwave chemical reactor for solvothermal reaction to obtain a composite precursor; the heating power of the microwave chemical reactor was 700 watts. The heating time of the microwave chemical reactor was 300 seconds. By adjusting the heating power and heating time of the microwave chemical reactor in step (3), the heating rate of the tubular furnace, and the ratio of the mixed atmosphere, alloy absorbing materials with different saturation magnetic intensities were prepared.

[0043] (4) The obtained precursor and ferrocene were placed in a tube furnace at a mass ratio of 1:2.75 and heat-treated to obtain a hierarchical carbon-coated alloy final product. The tube furnace heat treatment temperature was increased at a rate of 1.5 degrees Celsius per minute. The tube furnace heat treatment time was 45 minutes. The tube furnace heat treatment atmosphere was a hydrogen-argon mixture with a hydrogen content of 10%.

[0044] The basic units of the binary alloy high-efficiency wave-absorbing material are a carbon layer material and a metal alloy component. One-dimensional nanotube layers are assembled into a three-dimensional nano-skeleton structure, and cobalt-iron alloy particles grow in the carbon layer.

[0045] Performance Testing

[0046] Figure 1 The X-ray diffraction pattern of the carbon-based alloy composite absorbing material with high saturation magnetic strength prepared by the present invention shows that the synthesized product is consistent with the standard PDF card of cobalt-iron alloy, indicating that the carbon-based cobalt-iron alloy composite material has been successfully prepared.

[0047] Figure 2 The EDX spectrum and element content of the carbon-based alloy composite absorbing material with high saturation magnetic intensity prepared by the present invention show that the element content of the catalyst is C:N:Co:Fe=93.19:3.41:0.74:0.66.

[0048] Figure 3 The wave absorption performance test diagram of the carbon-based alloy composite wave absorbing material with high saturation magnetic strength prepared by the present invention clearly shows that it can achieve effective absorption of electromagnetic waves in the Ku band, and the absorption efficiency is greater than 90%.

[0049] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A microwave-assisted method for rapidly preparing binary alloy high-efficiency microwave absorbing materials, characterized in that The steps include: (1) 400-600 mg of melamine was uniformly dispersed in 500 ml of deionized water, and 291 mg of cobalt nitrate hexahydrate was dispersed and dissolved in the above solution to form a precursor reaction solution A; (2) 657 mg of dimethylimidazole was dispersed and dissolved in 500 ml of deionized water to form solution B; (3) Solutions A and B were stirred and mixed and placed in a microwave chemical reactor for solvothermal reaction to obtain a composite precursor; the heating power of the microwave chemical reactor was 700 watts; and the heating time of the microwave chemical reactor was 300 seconds; (4) The obtained precursor and ferrocene are placed in a tube furnace at a mass ratio of 1:2.75 for heat treatment to obtain a hierarchical carbon-coated alloy final product.

2. The method for preparing a binary alloy high-efficiency wave absorbing material according to claim 1, characterized in that: By adjusting the heating power, heating time, heating rate of the tube furnace and mixed atmosphere ratio of the microwave chemical reactor in step (3), alloy absorbing materials with different saturation magnetic intensities are prepared.

3. The method for microwave-assisted rapid preparation of binary alloy high-efficiency microwave absorbing materials according to claim 1, characterized in that: The heating rate of the tubular furnace heat treatment in step (4) is 1.5 degrees Celsius per minute.

4. The method for microwave-assisted rapid preparation of binary alloy high-efficiency microwave absorbing materials according to claim 1, characterized in that: The heat treatment time in the tubular furnace in step (4) is 45 minutes.

5. The method for microwave-assisted rapid preparation of binary alloy high-efficiency microwave absorbing materials according to claim 1, characterized in that: In step (4), the heat treatment atmosphere in the tubular furnace is a hydrogen-argon mixture with a hydrogen content of 10%.

6. A binary alloy high-efficiency wave absorbing material prepared by the method according to any one of claims 1 to 5, characterized in that: The basic units of the binary alloy high-efficiency wave-absorbing material are a carbon layer material and a metal alloy component. One-dimensional nanotube layers are assembled into a three-dimensional nano-skeleton structure, and cobalt-iron alloy particles grow in the carbon layer.

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