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CN-118306981-B - Wave-absorbing composite material with hierarchical pore structure and preparation method thereof

CN118306981BCN 118306981 BCN118306981 BCN 118306981BCN-118306981-B

Abstract

The invention relates to a wave-absorbing composite material with a hierarchical pore structure and a preparation method thereof. The preparation method of the wave-absorbing composite material with the hierarchical pore structure comprises the steps of mixing graphene oxide, ferroferric oxide and nickel nitrate in a solvent to obtain composite printing slurry, then printing the composite printing slurry through 3D to obtain a composite hydrogel structure, freeze-drying and vacuum-drying to obtain composite aerogel, and then sequentially introducing a boron nitride interface and a silicon carbide nanowire into the composite aerogel in situ by utilizing chemical vapor deposition to obtain the wave-absorbing composite material with the hierarchical pore structure.

Inventors

  • YOU XIAO
  • DONG SHAOMING
  • YANG JINSHAN
  • HE PING

Assignees

  • 中国科学院上海硅酸盐研究所

Dates

Publication Date
20260512
Application Date
20230106

Claims (5)

  1. 1. A preparation method of a wave-absorbing composite material with a hierarchical pore structure is characterized by comprising the steps of mixing graphene oxide, ferroferric oxide and nickel nitrate in a solvent to obtain composite printing slurry, and then printing the composite printing slurry through 3D to obtain a composite hydrogel structure; The mass ratio of the ferroferric oxide to the graphene oxide is 3:1-1:3, and the mass ratio of the nickel nitrate to the graphene oxide is 1:10-60; The air pressure of the 3D printing nozzle is 0.1-0.4 MPa, the diameter of the nozzle is 0.3-0.6 mm, the moving speed of the nozzle is 10-30 mm/s, the spacing between monofilaments in the layer is 0.3-0.6 mm, and the spacing between upper layers and lower layers is 0.3-0.6 mm; The temperature of the chemical vapor deposition boron nitride interface is 800-900 ℃, the reaction pressure is 1-2 kPa, the reaction time is 0.5-2 hours, the flow rate of the reaction gas ammonia is 40-80 mL/min, and the flow rate of the reaction gas boron chloride is 10-20 mL/min.
  2. 2. The preparation method of claim 1, wherein the mass ratio of the ferroferric oxide to the graphene oxide is 1:1, and the mass ratio of the nickel nitrate to the graphene oxide is 1:50.
  3. 3. The preparation method of the composite hydrogel according to claim 1, wherein the composite hydrogel is freeze-dried at a temperature of-80 ℃ to-30 ℃ for 24-72 hours and vacuum-dried for 24-48 hours.
  4. 4. The preparation method of the chemical vapor deposition silicon carbide nanowire is characterized in that the temperature of the chemical vapor deposition silicon carbide nanowire is 1000-1100 ℃, the reaction pressure is 3-6 kPa, the reaction time is 1-8 hours, and the flow rate of the reaction gas methyltrichlorosilane is 220-360 mL/min.
  5. 5. The wave-absorbing composite material with the hierarchical pore structure obtained by the preparation method of claim 1 is characterized in that the porosity of the wave-absorbing composite material with the hierarchical pore structure is 20% -50%, the minimum reflection loss value is-17.7-33.6 dB, and the maximum effective absorption bandwidth is 2.0-6.2 GHz.

Description

Wave-absorbing composite material with hierarchical pore structure and preparation method thereof Technical Field The invention belongs to the field of wave-absorbing composite materials, and particularly relates to a wave-absorbing composite material with a hierarchical pore structure and a preparation method thereof. Background Problems such as electromagnetic pollution, electromagnetic information leakage and the like caused by rapid development of electronic technology lead high-performance wave-absorbing composite materials to be widely concerned. Silicon carbide is used as a wide forbidden band semiconductor material, has the characteristics of low density, high strength, corrosion resistance, oxidation resistance and the like, and simultaneously has proper conductivity and excellent dielectric property. On the basis, the silicon carbide nanowire is considered as an ideal high-temperature wave absorbing material because of large specific surface area, high surface atomic ratio and more surface dangling bonds, and meanwhile, a through conductive network structure can be constructed. However, the electromagnetic parameters of a single silicon carbide nanowire are difficult to realize the impedance matching characteristic, and meanwhile, the electromagnetic wave loss mechanism is single, the dielectric loss strength is insufficient, the reflection is strong, the absorption is weak, and the practical application requirements of the wave-absorbing material are difficult to meet. Therefore, the construction of a composite material composed of a multi-dimensional structure and a multi-phase is considered as an effective way for realizing the optimization of the wave absorbing performance by introducing various wave absorbing mechanisms. The unique electronic structure and adjustable dielectric property of graphene endow the graphene with excellent electromagnetic wave absorption characteristics, so the graphene is regarded as an ideal structural unit of the wave-absorbing composite material. The large specific surface area of the graphene can effectively prolong the transmission path of electromagnetic waves, and the formed three-dimensional network structure can enhance the multiple scattering of the electromagnetic waves and promote the conductive loss effect on the electromagnetic waves. The combination of the three-dimensional graphene and the silicon carbide nanowire constructs a multi-level pore structure, so that the scattering effect of electromagnetic waves is effectively increased, and the interference cancellation caused by scattering enables the loss of the electromagnetic waves in the propagation process to be obviously increased. Meanwhile, the impedance matching degree of the composite material can be improved, and the dielectric loss effect on electromagnetic waves is realized by the introduced interface polarization and dipole polarization effects. However, the construction of the three-dimensional graphene structure and the distribution state of the three-dimensional graphene structure and the silicon carbide nanowire are difficult to accurately regulate and control, and meanwhile, the matching of the intrinsic dielectric properties of graphene and the silicon carbide material still needs to be further optimized. Disclosure of Invention The invention provides a wave-absorbing composite material with a hierarchical pore structure and a preparation method thereof. The invention provides a preparation method of a wave-absorbing composite material with a hierarchical pore structure, which comprises the steps of mixing graphene oxide, ferroferric oxide and nickel nitrate in a solvent to obtain composite printing slurry, then printing the composite printing slurry through 3D to obtain a composite hydrogel structure, freeze-drying and vacuum-drying to obtain composite aerogel, and then sequentially introducing a boron nitride interface and a silicon carbide nanowire into the composite aerogel in situ by utilizing chemical vapor deposition to obtain the wave-absorbing composite material with the hierarchical pore structure. Preferably, the mass ratio of the ferroferric oxide to the graphene oxide is 3:1-1:3, preferably 1:1, and the mass ratio of the nickel nitrate to the graphene oxide is 1:10-60, preferably 1:50. Preferably, the air pressure of the 3D printing nozzle is 0.1-0.4 MPa, the diameter of the nozzle is 0.3-0.6 mm, the moving speed of the nozzle is 10-30 mm/s, the spacing between monofilaments in the layer is 0.3-0.6 mm, and the spacing between upper and lower layers is 0.3-0.6 mm. Preferably, the freeze drying temperature of the composite hydrogel is-80 ℃ to-30 ℃ for 24-72 hours, and the vacuum drying time is 24-48 hours. Preferably, the temperature of the chemical vapor deposition boron nitride interface is 800-900 ℃, the reaction pressure is 1-2 kPa, the reaction time is 0.5-2 hours, the flow rate of the reaction gas ammonia is 40-80 mL/min, and the flow rate of the reaction gas boron