CN-118530029-B - Si3N4/SiO2 core-shell structure powder material and preparation method and application thereof

CN118530029BCN 118530029 BCN118530029 BCN 118530029BCN-118530029-B

Abstract

The invention discloses a Si 3 N 4 /SiO 2 core-shell structure powder material, a preparation method and application thereof, which belong to the technical field of wave-transparent ceramics, wherein Si 3 N 4 particles are used as a matrix, KH550, silicone oil and the like are mixed by mass and then added into an acetone solution of Si 3 N 4 particles, the obtained mixture is heated and stirred, and a lubricant is added dropwise to obtain a composite solution system, so that KH550 and silicone oil are coated on the surface of the matrix, the obtained composite is centrifuged, the obtained composite is subjected to wind treatment to obtain an intermediate product, and the coating and wind treatment are repeated to obtain the Si 3 N 4 /SiO 2 core-shell structure powder material. The loss tangent of the Si 3 N 4 /SiO 2 core-shell structure powder material provided by the invention is between 2.25 and 4.77 multiplied by 10 ‑3 , and the dielectric constant of graphene can be adjusted within the range of 2.74 to 6.55.

Inventors

WANG XINYU
ZHAO CHENYAO
Guo Rongzhao
QIU JIAHAO
ZHANG JIAQI
ZHANG YANXIN

Assignees

哈尔滨工业大学（威海）

Dates

Publication Date: 20260512
Application Date: 20240410

Claims (1)

1. The application of the Si 3 N 4 /SiO 2 core-shell structure powder material in adjusting the dielectric constant of graphene is characterized in that the preparation method of the Si 3 N 4 /SiO 2 core-shell structure powder material comprises the following steps: s1, dissolving 10g of alpha-Si 3 N 4 nano particles in 250g of acetone solution; s2, mixing 1g of KH550 with 1g of silicone oil, and adding the mixture into the acetone solution to obtain a mixture; S3, stirring the mixture prepared in the step S2 at 80 ℃ for 60min, and dropwise adding 1g of oleic acid in the stirring process; S4, centrifuging the mixture obtained by dropping the oleic acid in the step S3, and then, passing air for 20S under the air atmosphere and the air temperature condition of 340 ℃ to obtain an intermediate product 1; S5, dissolving 15g of the intermediate 1 prepared by S4 in 250g of acetone, and repeating S2-S4 to obtain an intermediate 2; s6, dissolving 10g of the intermediate product 2 prepared by S5 in 250g of acetone, and repeating S2-S4 to obtain the Si 3 N 4 /SiO 2 core-shell structure powder material.

Description

Si3N4/SiO2 core-shell structure powder material and preparation method and application thereof Technical Field The invention belongs to the technical field of wave-transparent ceramics, and particularly relates to a Si 3N4/SiO2 core-shell structure powder material and a preparation method and application thereof. Background In the military field, with rapid development of radar technology, weaponry and military targets are not hidden, and in order to improve the combat performance of weaponry, it is necessary to hide the weaponry from radar detection. In modern military industry, the stealth capability of military equipment has become an important indicator for measuring the mechanical properties of military equipment, and stealth coatings have become important materials for determining the viability of military equipment to a certain extent. The stealth technology can greatly improve the outburst prevention capability, the survivability and the combat effect of the combat platform and the weapon system, can obtain the initiative advantages of the strategy, the tactics, the technology and the like, and has become a key technology for research in the modern national defense field. Among many materials, graphene is widely used in the field of electromagnetic wave absorption due to its excellent properties. Graphene is a material with excellent electrical, thermal and mechanical properties and high specific surface area. Graphene Oxide (GO) is a single-layer material formed by stripping graphite, and reduced graphene oxide (rGO) is prepared from graphene oxide serving as a raw material by photocatalysis, heat treatment and other methods, and is suitable as an electromagnetic wave absorbing material due to the characteristics of high dielectric constant, large porosity and high specific surface area. In addition, the unusual energy band structure of the graphene allows the existence of independent holes and electrons, and the special structure not only improves the impedance matching performance of the graphene and provides energy for transition from adjacent energy levels to fermi energy levels, but also introduces defect polarization relaxation and dipole relaxation, and is beneficial to the absorption of electromagnetic waves. However, the high complex dielectric constant and the low complex permeability constant lead to poor impedance matching and obvious deviation from the zero reflection condition, which also leads to the fact that the wave absorbing performance of the graphene cannot meet the use requirement. At present, the main problem of using graphene as a wave-absorbing material is that impedance matching of the graphene is not ideal, and the problem can be solved by preparing the graphene wave-absorbing composite material by taking the graphene as a matrix. By introducing proper doping bodies, the electromagnetic parameters of the composite material can be regulated and controlled, and the impedance matching is cooperatively optimized, so that better wave absorbing performance is realized. However, the existing magnetic loss type graphene wave-absorbing composite material constructed by doping ferrite, magnetic nano particles and other methods generally has the problems of high density, narrow effective absorption band, corrosion resistance and the like, and does not meet the requirements of 'light weight, high strength, wide frequency and thin layer' of the wave-absorbing material of the new generation. Therefore, a new material with high strength and low density, which can adjust the dielectric constant of graphene and solve the impedance mismatch problem, is needed. Disclosure of Invention The invention aims to provide a Si 3N4/SiO2 core-shell structure powder material, a preparation method and application thereof, so as to solve the problems in the prior art. One of the technical schemes provided by the invention is as follows: A preparation method of a Si 3N4/SiO2 core-shell structure powder material comprises the steps of taking Si 3N4 particles as a matrix, mixing KH550 (gamma-aminopropyl triethoxysilane) with silicone oil and the like by mass, adding the mixture into an acetone solution of Si 3N4 particles, heating and stirring the mixture, adding a lubricant dropwise to obtain a composite solution system, coating KH550 and silicone oil on the surface of the matrix, centrifuging the composite, carrying out air treatment on the obtained composite to obtain an intermediate product, and repeatedly coating and carrying out air treatment to obtain the Si 3N4/SiO2 core-shell structure powder material. The invention utilizes the characteristic that the organic matters are easy to form a film, realizes the film coating and shaping of the particle surfaces by dispersing and solidifying the organic matters in the powder, so that the organic matters between the particles are prevented from bonding, the framework structure of the film layer is a continuous silicon-oxygen chain group, partial oxygen bri