Preparation method of rhombic dodecahedron cavity structure electromagnetic wave absorber fe / zno@c
By preparing Fe/ZnO@C composite material with a rhombic dodecahedral cavity structure, the shortcomings of existing magnetic metal materials in electromagnetic wave absorption have been overcome, achieving a wide-bandwidth and highly efficient electromagnetic wave absorption effect, which is suitable for military stealth and electromagnetic pollution prevention.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHENGDU AIRCRAFT INDUSTRY GROUP
- Filing Date
- 2023-04-21
- Publication Date
- 2026-05-12
AI Technical Summary
Existing single-component magnetic metal materials suffer from problems such as narrow bandwidth, high density, low absorption intensity, and easy corrosion in electromagnetic wave absorption, making it difficult to meet the needs of modern military and electromagnetic pollution prevention.
The Fe/ZnO@C composite material with a rhombic dodecahedral cavity structure is prepared by hydrothermal reduction of Fe3O4 particles to form a ZIF-8 shell, and then calcined at high temperature to form an outer carbon shell and an inner ZnO component, thus achieving the synergistic effect of the ternary components.
The prepared Fe/ZnO@C material has good electromagnetic wave absorption performance. The outer carbon shell protects the internal metal, the middle cavity reduces the density, ZnO provides dielectric loss, and Fe provides magnetic loss, thus achieving wideband electromagnetic wave absorption.
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Figure CN116463105B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of composite material technology, specifically to a method for preparing Fe / ZnO@C, an electromagnetic wave absorber with a rhombic dodecahedral cavity structure. Background Technology
[0002] The rapid development of electronic technology has brought tremendous convenience to our daily lives, but it has also generated significant electromagnetic pollution. Electromagnetic pollution has become another major source of pollution after air, water, and noise pollution, and excessive electromagnetic radiation seriously affects human physical and mental health. In modern warfare, the increasing sophistication of radar detection technology has spurred a greater demand for radar-absorbing stealth capabilities in ships and aircraft. Therefore, developing highly efficient electromagnetic wave absorbing materials to adapt to increasingly demanding battlefield environments has become a hot topic in military and defense worldwide.
[0003] Because single-component magnetic metal materials have weaknesses such as narrow absorption band, high density, low absorption intensity, and easy corrosion, they cannot meet current needs. Therefore, the preparation of multi-component composite microwave absorbers has become the mainstream research direction.
[0004] Fe / ZnO@C, as an electromagnetic wave absorber with a special rhombic dodecahedral cavity structure, has an outer carbon shell that helps protect the internal metal components and dielectric loss, while the middle cavity reduces the material density. ZnO, as a high dielectric material, provides dielectric loss, and Fe provides magnetic loss. The synergistic effect of the ternary components enables it to have a good absorption effect on electromagnetic waves. Summary of the Invention
[0005] This invention proposes a method for preparing Fe / ZnO@C electromagnetic wave absorber with a rhombic dodecahedral cavity structure. The method is simple to prepare and the finished product has good electromagnetic wave absorption performance.
[0006] To achieve the above-mentioned objectives, the technical solution of the present invention is as follows:
[0007] A method for preparing a rhombic dodecahedral cavity structure electromagnetic wave absorber Fe / ZnO@C includes: synthesizing magnetic Fe3O4 particles; preparing a precursor Fe3O4 / ZIF-8; coating the surface of the precursor Fe3O4@ZIF-8 with polydopamine to obtain an intermediate Fe3O4@ZIF-8@PDA; and obtaining a rhombic carbon shell coated zinc-iron alloy Fe / ZnO@C through high-temperature carbonization treatment.
[0008] In one embodiment, the preparation process of Fe3O4 particles includes: dissolving FeCl3∙6H2O and NaHCO3 in deionized water respectively, mixing them, adding L-ascorbic acid, sonicating the mixture, placing the resulting mixed solution in a reaction vessel, and hydrothermally reacting it at 80-140 °C for 2-8 h. The resulting solution is then cooled, washed, filtered, and dispersed in a methanol solution.
[0009] In one embodiment, the molar ratio of FeCl3∙6H2O to NaHCO3 is 1:2-4; the molar ratio of FeCl3∙6H2O to L-ascorbic acid is 1:0.1-0.2.
[0010] In one embodiment, the preparation process of the precursor Fe3O4 / ZIF-8 includes: taking 1-5 mL of the aforementioned Fe3O4 methanol solution and diluting it with methanol to 40 mL, adding 0.6 g PVP, and adding Zn(NO3)2∙6H2O and 2-methylimidazole (DMI) methanol solutions dropwise, ultrasonically stirring and standing, filtering the obtained product, washing and drying.
[0011] In one embodiment, the mass ratio of Zn(NO3)2∙6H2O to 2-methylimidazole (DMI) is 1:1-4.
[0012] In one embodiment, the preparation process of the intermediate Fe3O4 / ZIF-8@PDA includes: ultrasonically dispersing the prepared precursor Fe3O4 / ZIF-8 in deionized water, adding dopamine hydrochloride and 3-hydroxymethylaminomethane (THAM) respectively, stirring, washing the resulting product with water, filtering, and drying.
[0013] In one embodiment, the preparation process of Fe / ZnO@C includes: placing the obtained intermediate Fe3O4 / ZIF-8@PDA in a tube furnace and calcining it at high temperature under an argon atmosphere to obtain Fe / ZnO@C.
[0014] In one embodiment, the hydrothermal reaction temperature is 120 °C and the reaction time is 6 h.
[0015] In one embodiment, the mass ratio of Fe3O4 / ZIF-8 to dopamine hydrochloride is 1:2-6; the mass ratio of dopamine hydrochloride to 3-hydroxymethylaminomethane (THAM) is 1:0.5-2.
[0016] In one embodiment, the intermediate Fe3O4 / ZIF-8@PDA is calcined at a temperature of 500-800℃ for 1-6 hours.
[0017] In one embodiment, 2 mL of Fe3O4 methanol solution was diluted to 40 mL; the concentration of Zn(NO3)2∙6H2O was 0.05 g / mL methanol, and the mass ratio of Zn(NO3)2∙6H2O to 2-methylimidazole (DMI) was 1:1.5.
[0018] In one embodiment, the mass ratio of Fe3O4 / ZIF-8 to dopamine hydrochloride is 1:4; the mass ratio of dopamine hydrochloride to 3-hydroxymethylaminomethane (THAM) is 1:1.
[0019] In one embodiment, the calcination temperature of Fe3O4 / ZIF-8@PDA is 700°C and the calcination time is 2 h.
[0020] In summary, the present invention has the following advantages:
[0021] 1. From the perspective of the synthesis process, the preparation method of this invention involves preparing water-soluble Fe3O4 particles through hydrothermal reduction, and further forming ZIF-8 on its outer surface through a static method. However, the addition of dopamine hydrochloride will destroy Zn. 2+ Through coordination with DMI, ZIF-8 undergoes partial self-etching. Following high-temperature calcination, Fe3O4 is reduced to elemental iron, and the zinc in ZIF-8 forms ZnO organic components, creating a carbon skeleton. The poly(dopamine hydrochloride) carbonizes to form a shell, coating the outermost layer, yielding the final product Fe / ZnO@C. This method is simple to prepare and suitable for large-scale production; furthermore, the material has a novel structure, relatively low density, and excellent product performance.
[0022] 2. This method prepares Fe / ZnO@C as an electromagnetic wave absorber with a special structure of rhombic dodecahedral cavity. The outer carbon shell helps protect the internal metal components and dielectric loss, while the middle cavity can reduce the material density. ZnO, as a high dielectric material, provides dielectric loss, and Fe provides magnetic loss. The synergistic effect of the ternary components enables it to have a good electromagnetic wave absorption effect, which can be applied in the field of military stealth. Attached Figure Description
[0023] Figure 1 The image shows a scanning electron microscope (SEM) image of the composite absorbing material of Example 1: Fe / ZnO@C-1.
[0024] Figure 2 The X-ray diffraction pattern of the composite absorbing material in Example 1 is: Fe / ZnO@C-1.
[0025] Figure 3 The reflection loss curve for Example 1 is: Fe / ZnO@C-1. Detailed Implementation
[0026] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments and accompanying drawings, further clarifies the invention. Those skilled in the art should understand that the specific descriptions below are illustrative rather than restrictive and should not be construed as limiting the scope of protection of the present invention. The terms "first," "second," etc., used in the specification, claims, and accompanying drawings are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that comprises a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, or apparatuses.
[0027] Example 1
[0028] The preparation method of Fe / ZnO@C-1, an electromagnetic wave absorber with a rhombic dodecahedral cavity structure, is as follows:
[0029] (a) Preparation of Fe3O4 particles
[0030] 0.8109 g (3 mmol) FeCl3∙6H2O and 0.7560 g (9 mmol) NaHCO3 were dissolved in 40 mL of deionized water, respectively. After mixing, 0.088 g (0.5 mmol) L-ascorbic acid was added and the mixture was sonicated for 10 min. The resulting mixed solution was placed in a reaction vessel and hydrothermally reacted at 120 °C for 6 h. After washing, the solution was filtered and dispersed in a methanol solution with a concentration of approximately 120 mg / mL methanol.
[0031] (II) Preparation of Fe3O4 / ZIF-8
[0032] Take 4 mL of the above Fe3O4 methanol solution in a beaker, dilute with methanol to 40 mL, add 0.6 g PVP (polyvinylpyrrolidone), 2.0 g Zn(NO3)2∙6H2O and 3.0 g 2-methylimidazole (DMI) dissolved in 40 mL of methanol respectively, and then add them dropwise to the Fe3O4 / methanol solution. Stir ultrasonically for 30 min and let stand for 24 h. Filter, wash and dry the resulting product.
[0033] (III) Preparation of Fe3O4 / ZIF-8@PDA
[0034] 0.1 g Fe3O4 / ZIF-8 was ultrasonically dispersed in deionized water, and 0.4 g dopamine hydrochloride and 0.4 g 3-hydroxymethylaminomethane (THAM) were added respectively. The mixture was mechanically stirred for 12 h, and the resulting product was washed with water, filtered, and dried.
[0035] (iv) Preparation of Fe / ZnO@C-1
[0036] The intermediate Fe3O4 / ZIF-8@PDA was placed in a tube furnace and calcined at 700℃ for 2 hours under an argon atmosphere to obtain Fe / ZnO@C.
[0037] From the perspective of the synthesis process, this invention prepares water-soluble Fe3O4 particles through hydrothermal reduction, and further forms ZIF-8 on their outer surface through a static method. The added dopamine hydrochloride will destroy Zn. 2+ Through coordination with DMI, ZIF-8 undergoes partial self-etching. Finally, after high-temperature calcination, Fe3O4 is reduced to elemental iron, and the zinc element in ZIF-8 forms ZnO organic components that form a carbon skeleton. Meanwhile, polyhydrochloric acid dopamine carbonizes to form an outer shell that coats the outermost layer, resulting in the final product Fe / ZnO@C.
[0038] Fe / ZnO@C, as an electromagnetic wave absorber with a special rhombic dodecahedral cavity structure, has an outer carbon shell that helps protect the internal metal components and dielectric loss, while the middle cavity reduces the material density. ZnO, as a high dielectric material, provides dielectric loss, and Fe provides magnetic loss. The synergistic effect of the ternary components enables it to have a good absorption effect on electromagnetic waves.
[0039] like Figure 1 and Figure 2 As shown, scanning electron microscopy and X-ray diffraction both indicate that this method successfully prepared the three-component composite Fe / ZnO@C with a rhombic dodecahedral cavity structure. Figure 1 In the scanning electron microscope image shown, Fe and ZnO particles are embedded in the surface of a rhombic dodecahedral cavity.
[0040] Preliminary tests using a network vector analyzer and subsequent simulations using MATLAB both demonstrate that Fe / ZnO@C possesses excellent microwave absorption properties, illustrating the feasibility of this method.
[0041] like Figure 3 As shown, Fe / ZnO@C has a minimum reflection loss of -53.8 dB at a thickness of 1.72 mm, and an effective absorption bandwidth of up to 6.89 GHz at a thickness of 2.3 mm.
[0042] Example 2: Preparation method of Fe / ZnO@C-2 electromagnetic wave absorber with rhombic dodecahedral cavity structure
[0043] (a) Preparation of Fe3O4 particles
[0044] 0.8109 g (3 mmol) FeCl3∙6H2O and 0.504 g (6 mmol) NaHCO3 were dissolved in 40 mL of deionized water, respectively. After mixing, 0.0528 g (0.3 mmol) L-ascorbic acid was added and the mixture was sonicated for 10 min. The resulting mixed solution was placed in a reaction vessel and hydrothermally reacted at 80 °C for 2 h. After washing, the solution was filtered and dispersed in a methanol solution with a concentration of approximately 120 mg / mL methanol.
[0045] (II) Preparation of Fe3O4 / ZIF-8
[0046] Take 3 mL of the above Fe3O4 methanol solution in a beaker, dilute with methanol to 40 mL, add 0.6 g PVP (polyvinylpyrrolidone), 2.0 g Zn(NO3)2∙6H2O and 2.0 g 2-methylimidazole (DMI) dissolved in 40 mL of methanol respectively, and then add them dropwise to the Fe3O4 / methanol solution. Stir ultrasonically for 30 min and let stand for 24 h. Filter, wash and dry the resulting product.
[0047] (III) Preparation of Fe3O4 / ZIF-8@PDA
[0048] 0.1 g Fe3O4 / ZIF-8 was ultrasonically dispersed in deionized water, and 0.6 g dopamine hydrochloride and 0.3 g 3-hydroxymethylaminomethane (THAM) were added respectively. The mixture was mechanically stirred for 12 h, and the resulting product was washed with water, filtered, and dried.
[0049] (iv) Preparation of Fe / ZnO@C-2
[0050] The intermediate Fe3O4 / ZIF-8@PDA was placed in a tube furnace and calcined at 500°C for 6 hours under an argon atmosphere to obtain Fe / ZnO@C-2.
[0051] Example 3: Preparation method of Fe / ZnO@C-3 electromagnetic wave absorber with rhombic dodecahedral cavity structure
[0052] (a) Preparation of Fe3O4 particles
[0053] 0.8109 g (3 mmol) FeCl3∙6H2O and 1.0080 g (12 mmol) NaHCO3 were dissolved in 40 mL of deionized water, respectively. After mixing, 0.0792 g (0.45 mmol) L-ascorbic acid was added and the mixture was sonicated for 10 min. The resulting mixed solution was placed in a reaction vessel and hydrothermally reacted at 100 °C for 4 h. After washing, the solution was filtered and dispersed in a methanol solution with a concentration of approximately 120 mg / mL methanol.
[0054] (II) Preparation of Fe3O4 / ZIF-8
[0055] Take 5 mL of Fe3O4 methanol solution in a beaker, dilute with methanol to 40 mL, add 0.6 g PVP (polyvinylpyrrolidone), 2.0 g Zn(NO3)2∙6H2O and 8.0 g 2-methylimidazole (DMI) dissolved in 40 mL methanol respectively, and then add these solutions dropwise to the Fe3O4 / methanol solution. Add 0.6 g PVP, sonicate for 30 min, and let stand for 24 h. Filter, wash and dry the resulting product.
[0056] (III) Preparation of Fe3O4 / ZIF-8@PDA
[0057] 0.1g Fe3O4 / ZIF-8 was ultrasonically dispersed in deionized water, and 0.2g dopamine hydrochloride and 0.4g 3-hydroxymethylaminomethane (THAM) were added respectively. The mixture was mechanically stirred for 12h, and the resulting product was washed with water, filtered, and dried.
[0058] (iv) Preparation of Fe / ZnO@C-3
[0059] The intermediate Fe3O4 / ZIF-8@PDA was placed in a tube furnace and calcined at 600℃ for 4 hours under an argon atmosphere to obtain Fe / ZnO@C-3.
[0060] Example 4: Preparation method of Fe / ZnO@C-4 electromagnetic wave absorber with rhombic dodecahedral cavity structure
[0061] (a) Preparation of Fe3O4 particles
[0062] 0.8109 g (3 mmol) FeCl3∙6H2O and 0.7560 g (9 mmol) NaHCO3 were dissolved in 40 mL of deionized water, respectively. After mixing, 0.1056 g (0.6 mmol) L-ascorbic acid was added and the mixture was sonicated for 10 min. The resulting mixed solution was placed in a reaction vessel and hydrothermally reacted at 140 °C for 8 h. After washing, the solution was filtered and dispersed in a methanol solution with a concentration of approximately 120 mg / mL methanol.
[0063] (II) Preparation of Fe3O4 / ZIF-8
[0064] Take 1 mL of Fe3O4 methanol solution in a beaker, dilute with methanol to 40 mL, add 0.6 g PVP (polyvinylpyrrolidone), 2.0 g Zn(NO3)2∙6H2O and 6.0 g 2-methylimidazole (DMI) dissolved in 40 mL of methanol respectively, and then add these solutions dropwise to the Fe3O4 / methanol solution. Add 0.6 g PVP, sonicate for 30 min, and let stand for 24 h. Filter, wash and dry the resulting product.
[0065] (III) Preparation of Fe3O4 / ZIF-8@PDA
[0066] 0.1g Fe3O4 / ZIF-8 was ultrasonically dispersed in deionized water, and 0.3g dopamine hydrochloride and 0.45g 3-hydroxymethylaminomethane (THAM) were added respectively. The mixture was mechanically stirred for 12h, and the resulting product was washed with water, filtered, and dried.
[0067] (iv) Preparation of Fe / ZnO@C-4
[0068] The intermediate Fe3O4 / ZIF-8@PDA was placed in a tube furnace and calcined at 800℃ for 1 h under an argon atmosphere to obtain Fe / ZnO@C-4.
[0069] The embodiments described above are merely illustrative of the implementation methods of the present invention, but should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the protection scope of the present invention.
[0070] The embodiments described above are merely illustrative of the implementation methods of the present invention, but should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the protection scope of the present invention.
Claims
1. A method for preparing a rhombic dodecahedral cavity structure electromagnetic wave absorber Fe / ZnO@C, characterized in that, include: A methanol solution of magnetic Fe3O4 particles was synthesized; a precursor Fe3O4 / ZIF-8 was prepared; polydopamine was coated on the surface of the precursor Fe3O4 / ZIF-8 to obtain the intermediate Fe3O4 / ZIF-8@PDA; and a rhombic dodecahedral cavity structure electromagnetic wave absorber Fe / ZnO@C was obtained by high-temperature carbonization treatment. The preparation process of the precursor Fe3O4 / ZIF-8 includes: taking 1-5 mL of the aforementioned methanol solution of magnetic Fe3O4 particles, diluting it with methanol to 40 mL, adding 0.6 g of PVP, and then adding Zn(NO3)2 dissolved in it dropwise. A methanol solution of 6H2O and 2-methylimidazole DMI was ultrasonically stirred and allowed to stand. The resulting product was filtered, washed, and dried.
2. The preparation method according to claim 1, characterized in that, The aforementioned process for preparing a methanol solution of magnetic Fe3O4 particles includes: [The process involves] mixing FeCl3... 6H2O and NaHCO3 were dissolved in deionized water, mixed, and L-ascorbic acid was added. After ultrasonic treatment, the resulting mixed solution was placed in a reaction vessel and hydrothermally reacted at 80-140 ℃ for 2-8 h. The resulting solution was cooled, washed, filtered, and dispersed in a methanol solution.
3. The preparation method according to claim 2, characterized in that, FeCl3 The molar ratio of 6H2O to NaHCO3 is 1:2-4; FeCl3 The molar ratio of 6H2O to L-ascorbic acid is 1:0.1-0.
2.
4. The preparation method according to claim 1, characterized in that, Zn(NO3)2 The mass ratio of 6H2O to 2-methylimidazole DMI is 1:1-4.
5. The preparation method according to claim 1, characterized in that, The preparation process of intermediate Fe3O4 / ZIF-8@PDA includes: ultrasonically dispersing the prepared precursor Fe3O4 / ZIF-8 in deionized water, adding dopamine hydrochloride and 3-hydroxymethylaminomethane (THAM) respectively, stirring, washing the resulting product with water, filtering, and drying.
6. The preparation method according to claim 1 or 5, characterized in that, The preparation process of Fe / ZnO@C includes: placing the obtained intermediate Fe3O4 / ZIF-8@PDA in a tube furnace and calcining it at high temperature under an argon atmosphere to obtain Fe / ZnO@C.
7. The preparation method according to claim 2, characterized in that, The hydrothermal reaction temperature was 120 ℃, and the reaction time was 6 h.
8. The preparation method according to claim 5, characterized in that, The mass ratio of precursor Fe3O4 / ZIF-8 to dopamine hydrochloride is 1:2-6; the mass ratio of dopamine hydrochloride to 3-hydroxymethylaminomethane (THAM) is 1:0.5-2.
9. The preparation method according to claim 6, characterized in that, The intermediate Fe3O4 / ZIF-8@PDA was calcined at 500-800℃ for 1-6 h.
10. The preparation method according to claim 4, characterized in that, Dilute 2 mL of Fe3O4 methanol solution to 40 mL; Zn(NO3)2 The concentration of 6H2O is 0.05 g / mL methanol, Zn(NO3)2 The mass ratio of 6H2O to 2-methylimidazole DMI is 1:1.
5.
11. The preparation method according to claim 8, characterized in that, The mass ratio of precursor Fe3O4 / ZIF-8 to dopamine hydrochloride is 1:4; the mass ratio of dopamine hydrochloride to 3-hydroxymethylaminomethane (THAM) is 1:
1.
12. The preparation method according to claim 6, characterized in that, The intermediate Fe3O4 / ZIF-8@PDA was calcined at 700℃ for 2 h.