CN-122028395-A - VC/Al2O3FeCoNi phase derived in-situ composite material, and preparation method and application thereof

Abstract

The invention discloses a VC/Al 2 O 3 /FeCoNi phase derivative in-situ composite material, a preparation method and application thereof, and belongs to the field of electromagnetic wave absorbing materials. The invention aims to solve the problem of how to enhance the magneto-dielectric effect and interface polarization of MAX phase derivatives in electromagnetic attenuation. The invention introduces iron-cobalt-nickel magnetic metal elements into MAX phase derived vanadium carbide by a solid phase reaction method and a molten salt method to synthesize the VC/Al 2 O 3 /FeCoNi composite wave-absorbing material with a layered structure, wherein all the magnetic metal elements are uniformly distributed in layered VC with lattice defects. The VC/Al 2 O 3 /FeCoNi composite material prepared by the method has a hetero-interface structure and rich vacancy defects, and the unique structural design synchronously realizes triple effects of enhancing magnetic loss, introducing rich interface polarization and optimizing impedance matching. The invention exploits the potential of MAX phase derivatives in the field of electromagnetic attenuation.

Inventors

• LI JUN
• ZHANG ZEYANG
• WU HUANTONG
• WANG HAOMING
• Deng Nandong
• Hua Zhuyu
• YU CHUNYU
• ZHOU ZHONGXIANG

Assignees

• 哈尔滨工业大学

Dates

Publication Date

20260512

Application Date

20260129

Claims (10)

1. 1. The VC/Al 2 O 3 /FeCoNi phase derivative in-situ composite material is characterized by taking vanadium carbide as a carrier, having a stacked layered structure, wherein iron cobalt nickel nanoparticles and aluminum oxide nanoparticles are inlaid between layers of the vanadium carbide, and having an FCC face-centered cubic structure.
2. 2. The composite material according to claim 1, wherein the particle size is mainly concentrated in the range of 1 μm to 10. Mu.m, and the atomic composition of each magnetic metal element is 15%.
3. 3. The composite of claim 1, wherein the alumina nanoparticles form a hetero-interface with the vanadium carbide.
4. 4. A method of preparing the composite material of claim 1,2 or 3, comprising the steps of: Mixing a V simple substance, al powder and graphite powder, performing wet ball milling by taking absolute ethyl alcohol as a dispersion medium, drying after ball milling, performing compression molding, and sintering under an inert atmosphere to obtain a precursor V 2 AlC MAX phase; And secondly, mixing and grinding the composite material with ferrous chloride tetrahydrate, nickel chloride hexahydrate, cobalt chloride hexahydrate, sodium chloride and potassium chloride, preserving heat, sintering, washing and centrifuging with deionized water until all molten salt is removed, and drying to obtain the composite material.
5. 5. The method according to claim 4, wherein in the first step, the simple substance V, the Al powder and the graphite powder are mixed in a ratio of 0.1:0.055-0.06:0.04-0.045.
6. 6. The method according to claim 4, wherein in the first step, the molding is performed under uniaxial pressure of 300 MPa, and the inert atmosphere is argon, and the sintering is performed at 1500 ℃ to 1550 ℃.
7. 7. The method of claim 4, wherein in step two, the precursor V 2 AlC MAX phase, ferrous chloride tetrahydrate, nickel chloride hexahydrate, cobalt chloride hexahydrate, sodium chloride and potassium chloride are mixed in a mass ratio of 0.6:0.8:0.99:0.99:0.99:1.26.
8. 8. The method according to claim 4, wherein in the second step, the temperature is raised from room temperature to 700 ℃ at a temperature rise rate of 5 ℃ per minute, and the sintering is performed at a temperature of 12 h ℃.
9. 9. The method according to claim 4, wherein in the second step, the drying is performed at 60 ℃ to 80 ℃.
10. 10. Use of a composite material according to any one of claims 1-3 or a composite material prepared by a method according to any one of claims 4-9 as an electromagnetic wave absorbing material.

Description

VC/Al 2O3/FeCoNi phase derivative in-situ composite material and preparation method and application thereof Technical Field The invention belongs to the field of electromagnetic wave absorbing materials, and particularly relates to a preparation method and application of a layered wave absorbing material with dielectric loss and magnetic loss. Background With the upgrading of the 5G communication scale application and the stealth requirement of national defense equipment, the problems of electromagnetic radiation treatment, precise electronic anti-interference, military target concealment and the like are remarkable, and the development of high-performance electromagnetic wave absorbing materials becomes one of the core research directions of material science. The 5G electromagnetic signals are mainly distributed in the low-frequency band in the range of 2-8 GHz, and the band radiates easily to interfere with electronic equipment, affects communication stability and information safety, and possibly threatens organism health, so that the development of electromagnetic wave absorbing (EMA) materials with high energy dissipation capacity is significant in relieving 5G electromagnetic pollution and guaranteeing equipment and human body safety, and has wide prospects in the field of military stealth. The ideal wave absorbing material needs to meet the indexes of excellent impedance matching, strong attenuation capability, outstanding environmental stability and the like, but the traditional single-phase wave absorbing material has a performance short plate, namely, the carbon material has obvious conductive loss, easy impedance mismatch, high reflectivity, excellent intrinsic magnetic performance, high magnetic loss, high density, insufficient high-frequency magnetic loss influenced by Snoek limit, narrow applicable frequency band, high magnetic permeability of pure metal nano particles, easy oxidation agglomeration, lack of effective dielectric loss synergy and difficult realization of broadband absorption, and the single mechanism limitation pushes researchers to turn to a multi-component composite system, and by constructing a magnetic-dielectric loss synergistic structure, how to realize uniform composite distribution of magnetic and dielectric components, effectively increase heterogeneous phase contact interfaces and further enrich interface polarization sites is still a key problem to be broken through in the research and development of the current wave absorbing material. According to the theory of magneto-dielectric synergistic effect (adv. Mate.2022, 2107538), the magnetic component and the dielectric/conductive component are organically combined in the composite material, and through the synergistic effect between the magnetic component and the dielectric/conductive component, two key targets can be synchronously achieved, namely good impedance matching, namely electromagnetic wave energy is maximally entered into the material, and is not reflected off the surface. And secondly, the strong attenuation capability is that electromagnetic wave energy entering the interior of the material is rapidly and efficiently consumed. The reflection loss is closely related to the complex permittivity and complex permeability of the material. When the values of permeability and permittivity are close, the characteristic impedance of the material is most matched to the impedance of free space, thereby minimizing surface reflection (Small 2021, 2100970). By introducing the magnetic component, the excessively high dielectric constant caused by the high dielectric component can be effectively reduced, and at the same time, the presence of the dielectric component also affects the magnetic response. The reasonable combination of the two can lead the equivalent electromagnetic parameters of the composite material to reach balance in a specific frequency band, thereby widening the frequency range of impedance matching. The MAX phase is a novel ternary lamellar compound with unique properties, and its derivatives are usually lamellar materials due to the flexible processability of the aluminum layer atoms. For example, two-dimensional MXene layered materials can be obtained by etching with acid solution, MXene is a dielectric wave-absorbing material, inherent conductivity and dipole polarization generated by surface functional groups endow the material with good dielectric loss capability (adv. Funct. Mater. 2023, 2301449), however, strong conductivity means that the reflectivity of electromagnetic waves is increased, the impedance matching optimization is not favored, and the absorption capability of the MXene at medium-low frequency (2-8 GHz) is reduced due to the lack of magnetic loss capability. The intrinsic modification is a good means of introducing a magnetic loss mechanism in the initial stage, and the study published in 2023 by dine et al proposes a "chemical scissors-mediated structure editing" strategy (Science,