28results about How to "Excellent electromagnetic wave absorption performance" patented technology

The invention discloses a wave-absorbing foam / honeycomb core composite board as well as a preparation method and application thereof. Comprising a honeycomb core substrate layer, a wave-absorbing foam embedding layer and a wave-transparent foam filling layer which are sequentially stacked, the honeycomb core substrate layer is a honeycomb core with a plurality of through hollow areas, and each surface of the honeycomb core is provided with a wave-absorbing coating; the wave-absorbing foam embedded layer comprises a plurality of filling parts and protruding parts, the hollow area of the honeycomb core substrate layer is filled with the filling parts, and the protruding parts are arranged on the surface of the honeycomb core substrate layer in a protruding mode and form a fluctuating structure; the wave-absorbing foam embedded layer is made of a wave-absorbing material; the wave-transparent foam filling layer is filled in the protruding parts, and a flat surface is formed on the side, away from the honeycomb core substrate layer, of the wave-transparent foam filling layer. The low-frequency absorption performance is improved on the premise that the total thickness is not increased, the multiple wave-absorbing characteristics of the wave-absorbing foam embedded layer are reserved, and meanwhile the excellent performance of the plane plate in the aspects of bearing, cutting and splicing is ensured.

The invention belongs to the technical field of wave-absorbing materials, and particularly relates to a monatomic modified carbon composite wave-absorbing material and a preparation method thereof. The method specifically comprises the following steps: S1, uniformly dispersing a pyrrole monomer and molybdenum trioxide hydride by using a solvent, and reacting at room temperature for 3-6 hours to obtain an HM-PPy compound; s2, adding metalloporphyrin and thionyl chloride into N, N-dimethylformamide, uniformly mixing, and then adding 4-dimethylaminopyridine to obtain a raw material solution; s3, dispersing the HM-PPy compound into a N, N-dimethylformamide solution containing triethylamine, so as to obtain a turbid liquid; s4, dropwise adding the raw material solution into the turbid liquid, and stirring and reacting at room temperature for 20-25 hours to obtain HM-PPy-MPor; and S5, carrying out pyrolysis on the HM (at) PPy-MPor to obtain the monatomic modified carbon composite wave-absorbing material.

The invention relates to the technical field of wave absorbing materials, and to a preparation method of a flaky carbonyl iron / molybdenum disulfide composite wave absorbing material and corresponding materials, comprising: adding sodium dodecylbenzene sulfonate, sodium molybdate, and thiourea to an ethanol solution according to a ratio and stirring to obtain a precursor solution; placing the precursor solution in a reactor for hydrothermal reaction to obtain a hydrothermal reaction solution, centrifugally washing the hydrothermal reaction solution to obtain a hydrothermal reaction product, vacuum drying the obtained hydrothermal reaction product to obtain a molybdenum disulfide nanomaterial; mixing the molybdenum disulfide nanomaterial with flaky carbonyl iron according to a ratio and grinding to obtain a mixed powder, bonding the mixed powder to obtain a flaky carbonyl iron / molybdenum disulfide composite wave absorbing material. The preparation method of the flaky carbonyl iron / molybdenum disulfide composite wave absorbing material and the corresponding materials of the invention can prepare a wave absorbing material with excellent electromagnetic wave absorption performance and can meet the absorption requirements of different frequency bands.

The invention relates to a preparation method of a lightweight reduced graphene oxide-silicon dioxide electromagnetic wave absorbing material. The invention belongs to the technical field of electromagnetic wave absorbing materials. The invention solves the problems that the impedance of the existing reduced graphene oxide is mismatched, the density of the modified reduced graphene oxide composite wave-absorbing material is increased and the preparation method is complicated. The method comprises the following steps: performing chemical crosslinking on graphene oxide, silicon dioxide and a silane coupling agent to obtain a precursor; and drying and sintering the precursor. The material prepared in the invention has good impedance matching and abundant interface polarization and relaxation effects, can effectively reduce the reflection loss value of electromagnetic waves and increase the effective absorption bandwidth of the electromagnetic waves, and has excellent electromagnetic wave absorption performance. When the thickness of the material is only 1.5 mm, the RL of the material can reach-54.08 dB, and when the thickness of the material is 1.7 mm, the effective absorption bandwidth of the material can reach 5.12 GHz. In addition, the density of the material is only 0.083 g / cm < 3 >, the process is simple, and stable batch production can be realized.

The invention relates to the technical field of high-performance composite materials, and provides a frequency band magnetic control adjustable one-dimensional nanotube composite wave-absorbing material and a preparation method thereof.The material is composed of a one-dimensional tubular ferroferric oxide matrix and manganous-manganic oxide wrapping the outer side of the matrix, and directional arrangement is conducted through magnetic control rotation. The preparation method comprises the following steps: preparing an iron oxyhydroxide precursor through a hydrothermal synthesis method; the preparation method comprises the following steps: reducing an iron oxyhydroxide precursor by a liquid-phase pyrolysis method, and coating a manganous-manganic oxide shell layer in situ at the same time, so as to obtain a nanotube ferroferric oxide / manganous-manganic oxide composite material; and carrying out orientation arrangement on the nanotube-shaped ferroferric oxide / manganous-manganic oxide composite material through magnetic field control. According to the preparation method and the structural design, the yield, the uniformity, the magnetic performance, the electromagnetic wave absorption efficiency, the multi-band electromagnetic loss enhancement and the like of the material are remarkably improved.

A preparation method of a magnetic metal nanoparticle-loaded nitrogen-doped wood carbon aerogel wave-absorbing material comprises the following steps: step 1, delignification is performed on cut natural wood, and then freeze drying is performed to obtain delignified wood aerogel; 2, the delignification wood aerogel and a metal adenine solution are subjected to a reaction in a reaction kettle, then freeze drying is conducted, and wood aerogel loaded with a metal adenine complex is obtained; 3, the wood aerogel loaded with the metal adenine complex is subjected to high-temperature carbonization treatment in inert gas, and the nitrogen-doped wood carbon aerogel wave-absorbing material loaded with the magnetic metal nanoparticles is obtained. According to the method, natural wood with a directional multilevel pore channel structure is used as a raw material, and a metal-organic complex grows in situ in a pore channel of the wood through solvothermal reaction. The invention aims to realize uniform dispersion and loading of magnetic nanoparticles in a wood carbon-based material so as to solve the problems of non-uniform structure, complex processing procedures and the like in the preparation process of the wave-absorbing material.

The invention relates to the technical field of functional resin-based composite materials, in particular to a chopped carbon fiber felt-based impact-resistant and wave-absorbing dual-function-integrated resin-based composite metamaterial and a simplified preparation process thereof.The chopped carbon fiber felt-based impact-resistant and wave-absorbing dual-function-integrated resin-based composite metamaterial comprises an upper dielectric layer, an array structure layer, a lower dielectric layer and a bottom reflecting layer which are sequentially stacked from top to bottom; the array structure layer is of a central symmetry structure and is formed by periodically arranging m * n carbon fiber felt structure units; the carbon fiber felt structural unit is a square annular patch, the outer ring width L1 of the square annular patch is 23-26 mm, the inner ring width L2 of the square annular patch is 10-15 mm, and the periodic side length P of the carbon fiber felt structural unit is 30 mm. Due to the miniaturization design of the structural units, the oblique incidence responses of the metamaterial in a transverse electric polarization mode and a transverse magnetic polarization mode can reach 45 degrees and 60 degrees respectively; and when the incident angle of the transverse magnetic wave is up to 60 degrees, 80% of electromagnetic wave absorptivity can still be maintained.

The invention provides a ternary composite nanofiber capable of being used for marine metal corrosion prevention and electromagnetic wave absorption and a preparation method and application of the ternary composite nanofiber. The preparation method of the ternary composite nanofiber comprises the following steps: (1) preparation of a precursor solution: dispersing a copper salt and a cobalt compound in a first solvent, stirring until the copper salt and the cobalt compound are fully dissolved, adding a polymer, and uniformly mixing to obtain the precursor solution; (2) preparation of a nanofiber membrane: performing electrostatic spinning on the precursor solution to obtain the nanofiber membrane loaded with copper and cobalt metal ions; and (3) carbonization: drying the nanofiber membrane, and performing high-temperature treatment after drying to obtain the ternary composite nanofiber capable of being used for marine metal corrosion prevention and electromagnetic wave absorption. The preparation method of the ternary composite nanofiber is simple and low in cost, and the prepared ternary composite nanofiber has a huge application prospect when being used for electromagnetic wave shielding in corrosion environments such as ocean.

The invention discloses a preparation method and application of a MgFe2O4 / coal gasification fine slag composite material, and the preparation method comprises the following steps: dissolving a divalent magnesium source and a trivalent iron source which can be dissolved in ethylene glycol according to a molar ratio of 1: 2 in ethylene glycol to obtain a solution A; taking 50-70 mL of the solution A, then adding 0.4-0.6 g of hexadecyl trimethyl ammonium bromide and 0.5-0.7 g of coal gasification fine slag, and carrying out uniform ultrasonic dispersion to obtain a solution B; and gradually dropwise adding alkali liquor into the solution B, continuously stirring in the process of dropwise adding the alkali liquor, stopping stirring when the pH value of the solution B reaches 10.5-11.5, then putting the obtained mixture into a 100mL high-pressure reaction kettle, heating to 160-190 DEG C in a closed manner, keeping the temperature for 10-15 hours, then cooling, washing and drying the obtained precipitate, thereby obtaining the MgFe2O4 / coal gasification fine slag composite material. According to the invention, the defects in the prior art are overcome, the resource utilization of the waste coal gasification fine slag is realized, and the preparation cost of the electromagnetic wave absorbing material is effectively reduced.

The invention relates to a MnCo-based metal oxide electromagnetic wave absorbing material as well as a preparation method and application thereof. The composition of the MnCo-based metal oxide electromagnetic wave absorbing material is Mn2. 05Co0. 91 O4, the preparation method comprises the following steps: preparing raw materials from a cobalt source, a manganese source, urea and ammonium persulfate according to a molar ratio, and dissolving the raw materials in deionized water to obtain a metal salt solution; carrying out hydrothermal reaction; centrifugally washing, drying and grinding; and calcining, and directly quenching after calcining to finally obtain the MnCo-based metal oxide electromagnetic wave absorbing material. The MnCo-based metal oxide electromagnetic wave absorbing material disclosed by the invention has excellent wave absorbing performance: by changing a quenching medium, customizing the lattice strain of the MnCo-based metal oxide, inducing the generation of unpaired electrons and optimizing the dielectric property of the MnCo-based metal oxide electromagnetic wave absorbing material, the wave absorbing performance of the MnCo-based metal oxide electromagnetic wave absorbing material is finally improved; the preparation process is simple and easy to implement, the metal oxide material with excellent and stable wave-absorbing performance is prepared through simple hydrothermal reaction, calcination and quenching processes, and the metal oxide material has great application prospects.

The application discloses a kind of natural rubber filling nickel-aluminum bimetallic hydroxide multi-walled carbon nanotube composite material for electronic component packaging, belong to packaging material technical field, the composite material includes natural rubber matrix and dispersed nickel-aluminum bimetallic hydroxide / multi-walled carbon nanotube hybrid filler, the hybrid filler is made of multi-walled carbon nanotube and nickel-aluminum layered double hydroxide grown in its surface in situ.Its preparation method is: multi-walled carbon nanotube, nickel source, aluminum source, urea and ammonium fluoride are dissolved in water and prepared hybrid filler by hydrothermal reaction;Then it is mixed with natural latex, vulcanization aid dispersion, freeze-drying, vulcanization is obtained.The application improves the dispersibility of filler by constructing LDH / MWCNT hybrid structure, uses phonon transmission optimization, synergism of loss and impedance, combustion inhibition and the friction and reinforcing mechanism of hybrid filler and natural rubber molecular chain, so that the thermal conductivity, electromagnetic wave absorption capacity, flame retardancy, mechanics and damping performance of the composite material are simultaneously improved, suitable for electronic component packaging field.

The invention belongs to the technical field of inorganic nonmetallic materials, and particularly relates to a preparation method and application of a cubic phase TiC nanosheet. The preparation method comprises the following steps: firstly, taking multi-layer Mxene (Ti3C2Tx) as a raw material, taking tetramethylammonium hydroxide as an intercalation agent, and thinning intercalation to obtain less-layer Ti3C2Tx; then 3-aminophenol is used for carrying out coating treatment on the Ti3C2Tx nanosheets, and the content of C on the surfaces of the few-layer Ti3C2Tx nanosheets is increased; and finally, taking the coated few-layer Ti3C2Tx as a template, and carrying out high-temperature calcination treatment in an argon atmosphere to obtain the cubic-phase TiC nanosheet. The cubic phase titanium carbide nanosheet prepared by the method has the advantages of controllable sheet shape, simple operation and mass production, and can be used in the field of electromagnetic wave absorption.

This invention belongs to the field of electromagnetic wave absorbing materials technology, and specifically discloses a hollow spherical Ti3C2T x @Molybdenum disulfide@cobalt / carbon composite materials, their preparation methods, and applications. The preparation method includes the following steps: reacting formaldehyde with melamine to prepare melamine-formaldehyde resin particles, ultrasonically dispersing them in water, and then adding Ti3C2T. x Suspension, stirred, melamine-formaldehyde resin particles with Ti3C2T x Self-assembly yields the core-shell material Ti3C2T x @MF; Ti3C2T x @MF, molybdenum source, and sulfur source are dispersed in water in a certain proportion and subjected to a hydrothermal reaction. The hydrothermal reaction product is washed and dried to obtain hollow spherical Ti3C2T x @Molybdenum disulfide composite material HTM; A dimethylimidazole alcohol solution is slowly added to a mixed alcohol solution of HTM and a cobalt source, stirred for a set time, and then allowed to stand for a set time to obtain HTM@ZIF67; HTM@ZIF67 is then pyrolyzed in an inert atmosphere to obtain hollow spherical Ti3C2T. x @Molybdenum disulfide@cobalt / carbon composite material. This material combination can effectively promote the attenuation of electromagnetic waves and reduce the material's filler content.

The invention relates to a ferric oxide / porous carbon heterogeneous composite wave-absorbing material as well as a preparation method and application thereof. The ferric oxide provides high magnetic conductivity and saturation magnetization intensity, the porous carbon formed by carbonizing the covalent organic framework with a regular structure can provide high conductive loss, a heterogeneous interface formed by the composite material provides abundant interface polarization, different element compositions provide dipole polarization, and the composite material has high magnetic conductivity and high saturation magnetization intensity. And good electromagnetic coupling enables the antenna to have excellent impedance matching and electromagnetic loss capabilities.

This invention discloses a cobalt-based Hassler alloy material, its preparation method, and its application. The preparation method includes the following steps: (1) Weighing cobalt powder, iron powder, and germanium powder in a molar ratio of 2:(1~1.75):(0.25~1), mixing them, placing them in a tungsten carbide grinding jar, adding anhydrous ethanol, adding grinding balls, and ball milling; (2) Drying and sieving the ball-milled powder, taking the sieved magnetic alloy powder, sealing it in a vacuum quartz tube, heat-treating it using a muffle furnace, and cooling it to room temperature with the furnace to obtain a cobalt-iron-germanium Hassler alloy. This invention uses a ball milling method, which can effectively change the surface morphology of the alloy powder, making it form a flake powder with a larger specific surface area, thereby improving the electromagnetic absorption performance of the magnetic alloy; by selecting and changing the proportion of the Hassler alloy components, the saturation magnetization of the magnetic alloy can be effectively increased, its Curie temperature can be increased, and the electromagnetic wave absorption performance of the magnetic alloy at high temperatures can be improved.

The invention discloses a corrosion-resistant pure magnetic porous foam wave-absorbing material and a preparation method thereof, and relates to the technical field of electromagnetic wave absorbing materials. According to the method, ferric hydroxide precipitate is subjected to a hydrothermal reaction to generate a ferric hydroxide one-dimensional nanowire, then the one-dimensional nanowire serves as a matrix, a porous foam material is prepared in a liquid nitrogen directional freezing and vacuum drying mode, and the corrosion-resistant pure magnetic porous foam wave-absorbing material is finally obtained through calcination in an ammonia atmosphere. According to the invention, orientation freezing is carried out by using ultralow-temperature liquid nitrogen, and then the foam material with a porous structure in specific orientation arrangement is successfully prepared through vacuum drying, so that electromagnetic waves can penetrate into the material along the pores, and more electromagnetic wave energy is converted into heat energy to be dissipated; and higher electromagnetic wave absorption performance can be realized. In addition, calcination is carried out in the ammonia atmosphere, no organic matter needs to be added, and the iron tetranitrogen pure magnetic porous foam material is finally obtained and shows higher corrosion resistance.

The invention belongs to the technical field of functional composite materials, and particularly relates to a hollow porous magnetic carbon fiber framework material, a composite coating with electromagnetic wave absorption and anti-corrosion functions, a preparation method and application. The hollow porous magnetic carbon fiber framework material is prepared by adopting a method comprising the following steps: transferring a mixture of nickel nitrate hexahydrate, 2, 5-dihydroxyterephthalic acid and DMF (Dimethyl Formamide) into a reaction kettle, and heating for reaction to obtain a nickel metal organic framework material; taking a mixture of PAN, copper nitrate monohydrate, a nickel metal organic framework material and PMMA as a shell layer solution, taking a polymethyl methacrylate solution as a core layer solution, and performing coaxial electrostatic spinning to obtain a core-shell structure nanofiber felt; and carrying out pre-oxidation, template sacrifice and carbonization treatment. Impedance matching of the coating filler can be effectively optimized, and excellent electromagnetic wave absorption performance is achieved through the synergistic effect of dielectric loss, magnetic loss and multi-interface polarization.

The application discloses a metal atom intercalated halogen end group MXene composite material and a preparation method and application thereof, and belongs to the technical field of electromagnetic functional materials. Through a thermodynamic guided molten salt chemical intercalation strategy, the Gibbs free energy difference between a reducing agent and a metal salt is used as a driving force to introduce elemental metal atoms into the interlayer of a halogen end group MXene and form an interlayer heterojunction. The electronegativity difference is used to reconstruct the interlayer charge distribution, significantly reduce the interlayer electron transport resistance, break through the bottleneck of halogen end group binding to electrons, greatly improve the carrier concentration, mobility and conductivity of the material, and realize excellent electromagnetic wave absorption performance by means of the synergistic enhancement of the conductivity loss and the interface polarization loss.

This invention discloses an electromagnetic wave absorbing material based on in-situ grown carbon nanotubes from FeCoNi alloy and its preparation method. First, an iron-based metal-organic framework is synthesized via a hydrothermal reaction, followed by ultrasonication, washing, and drying to obtain iron-based metal-organic framework nanoparticles. Then, the surface of the iron-based metal-organic framework nanoparticles is modified using polyvinylpyrrolidone, and Co is adsorbed onto them. 2+ and Ni 2+ Polyvinylpyrrolidone (MOF)-modified iron-cobalt-nickel (FeCoNi)-based metal-organic framework (MOF) nanoparticles were obtained. Finally, melamine and the cobalt-nickel-adsorbed MOF-modified FeCoNi-based MOF nanoparticles were subjected to a carbothermal reduction reaction under a nitrogen atmosphere to obtain the electromagnetic wave absorbing material. This invention relies on MOF porous templates and metal nanoparticles to catalyze the growth of carbon nanotubes, improving conductivity loss. Simultaneously, the interfacial polarization between the generated FeCoNi nanoparticles and the carbon matrix optimizes impedance matching and enhances electromagnetic wave absorption performance.

This invention belongs to the field of microwave absorbing materials technology, specifically relating to a carbon composite microwave absorbing material and its preparation method. The invention uses degummed waste filter cotton as a carbon source, employing an impregnation method to impregnate the pretreated waste filter cotton in magnetic metal salts, followed by heat treatment to obtain the composite microwave absorbing material. The carbon skeleton formed by the heat-treated waste filter cotton constitutes a conductive network in the composite material, exhibiting good dielectric loss. Magnetic metal elements and their alloys possess high saturation magnetization, providing magnetic loss in the composite material. The synergistic effect of dielectric and magnetic losses solves the problem of poor impedance matching in single carbon materials. The preparation process of this invention is simple and pollution-free, solving the environmental pollution problems caused by traditional waste filter cotton treatment methods, and is easy for large-scale production. The resulting composite microwave absorbing material is lightweight, efficient, has good impedance matching, and possesses excellent microwave absorption performance.

The invention discloses an anti-electromagnetic wave interference data line and a preparation method thereof, relates to the technical field of data lines, and aims to solve the problems that the data transmission quality is reduced and even data errors or communication faults are caused due to the fact that a traditional flexible flat cable in the prior art is prone to being interfered by electromagnetic waves. The data line main body comprises a wire core, a hot melt adhesive film and a reinforcing plate, the wire core is composed of a metal conductor, a wave absorbing layer, an insulating layer and an anti-electromagnetic wave interference layer, the wave absorbing layer is arranged on the outer side of the metal conductor, the insulating layer is arranged on the outer side of the wave absorbing layer, the anti-electromagnetic wave interference layer is arranged on the outer side of the insulating layer, and the reinforcing plate is arranged on the outer side of the insulating layer. The wave-absorbing layer is made of unsaturated polyester resin, a curing agent, a flame retardant, an additive, a stabilizer and wave-absorbing powder, and the insulating layer is made of a high-performance polyimide film material.

The invention discloses a rough-surface SiC / C nano-composite fiber and a preparation method and application thereof.Soluble precursor PCS and polymer PVP are used as initial materials, tetrahydrofuran and N, N-dimethylformamide are used as solvents, zinc acetylacetonate is used as an additive, and the rough-surface SiC / C nano-composite fiber is prepared. The SiC / C nanofibers with rough surfaces and good electromagnetic wave absorption performance are prepared through electrostatic spinning and high-temperature pyrolysis. The addition of zinc acetylacetonate not only effectively improves the structural stability of SiC / C, but also effectively widens the effective absorption width of the composite fiber due to the design of the surface rough structure. The process is simple, and the prepared fiber has good one-dimensional morphology and shows excellent electromagnetic wave absorption performance.

This invention discloses a method for depositing carbon nanofiber composite materials using lotus leaves as a substrate, its preparation, and its application. The method includes the following steps: Cleaned lotus leaves are placed in a catalyst aqueous solution and ultrasonically treated for 20-40 minutes. The solution is then poured into a polytetrafluoroethylene-lined reactor. The catalyst aqueous solution is a mixture of nickel nitrate and thiourea, with a molar ratio of 1:10-15. The total concentration of metal ions in the catalyst aqueous solution is 0.01-0.04 mol / L. The reactor is heated at 170-190℃ for 20-30 hours. After the reaction is complete, the solution is cooled, filtered, and the resulting solid is dried to obtain powder. The powder is placed in a quartz boat, the air is replaced with nitrogen, hydrogen is introduced, and the solution is heated to 430-470℃ for 5-15 minutes to reduce the catalyst. Subsequently, the solution is heated to 600-700℃ for reaction growth, with a single introduction of carbon nanofibers. 2 H 2 and H 2 and control N 2 C 2 H 2 and H 2 The flow rate ratio is 5-7:2-4:2-4. After growing for 20-40 minutes, the target product is obtained. The target product is then cooled.

This invention discloses a high-entropy spinel ceramic powder, its preparation method, and its applications. The high-entropy spinel ceramic powder of this invention has the chemical formula MFe₂O₄, where M is composed of at least 11 elements selected from Ba, Ca, Sr, Mg, Ti, Co, Ni, Fe, Cr, Mn, Cu, Zn, Mo, Al, and W. The preparation method of the high-entropy spinel ceramic powder of this invention includes the following steps: mixing metal oxide powder and Fe₂O₃ powder, wet ball milling, drying, and grinding; then adding the mixture to a graphite crucible and compacting it; followed by laser radiation heating to obtain the high-entropy spinel ceramic powder. The high-entropy spinel ceramic powder of this invention possesses excellent and stable microwave absorption properties and a high service temperature, making it suitable for use in stealth coatings for aerospace vehicles. Furthermore, its preparation method is simple and rapid, with a large potential for component synthesis, making it suitable for large-scale industrial production and application.

This invention belongs to the field of electromagnetic wave absorbing materials technology, specifically relating to a nickel-boron-doped cobalt-based layered carbon absorbing material and its preparation method. This invention utilizes a cobalt-based boron imidazole precursor framework as a template, and forms a two-dimensional layered layered double hydroxide (LDH) through a chemical oxidation etching process using nickel ions. This LDH is then subjected to high-temperature reduction to obtain the nickel-boron-doped cobalt-based layered carbon material. This material leverages the unique properties of two-dimensional materials to achieve high impedance matching, allowing electromagnetic waves to enter the absorber at a significant rate. Furthermore, the material's excellent dielectric polarization and magnetic coupling attenuate the electromagnetic waves entering the absorber. The material achieves a minimum reflection loss of -60.1 dB and a maximum effective absorption bandwidth of 6.24 GHz, giving it excellent electromagnetic wave absorption capabilities. The preparation method of this invention is simple and easy to mass-produce.

This invention discloses a method for preparing a core-shell structured TiO2@N / C@Co / C composite microwave absorber. Specifically, the method involves: preparing MIL-125-NH2 powder using a microwave-assisted synthesis method; preparing MIL-125-NH2@ZIF-8 powder using an ultrasonic synthesis method; mixing the MIL-125-NH2@ZIF-8 powder with Co(NO3)2·6H2O, adding methanol for ultrasonic dispersion and stirring, and then carbonizing the resulting MIL-125-NH2@ZIF-8@ZIF-67 powder. This invention effectively improves the impedance matching of the microwave absorber by introducing a multi-component MOF, allowing incident electromagnetic waves to enter the composite absorber for dissipation and attenuation. Furthermore, the abundant heterogeneous interfaces in the core-shell structure can induce interfacial polarization losses, thereby increasing the absorption of electromagnetic waves.

This invention belongs to the field of microwave absorbing materials technology, and specifically relates to a microwave absorbing material in the 3-5 GHz frequency band, its preparation method, and its applications. The microwave absorbing material of this invention comprises a high-dielectric two-dimensional layered material and a low-dielectric material coating the high-dielectric two-dimensional layered material; the high-dielectric two-dimensional layered material is MXene; and the low-dielectric material is aluminum fluoride. This invention employs a liquid-phase method, under nitrogen purging, to obtain aluminum fluoride sheet-like nanoparticles coated with Ti3C2T by etching the aluminum phase of TiAlC2MAX with high-concentration hydrochloric acid and lithium fluoride in one step. x The absorbing material is not only simple to prepare, but also has excellent electromagnetic absorption performance in the 3-5GHz frequency band, which can well meet the electromagnetic absorption requirements of national defense, communications and electronic appliances in daily life.

The invention provides a multi-element co-doped electromagnetic shielding functional material, a polyester master batch as well as a preparation method and application of the polyester master batch. The functional material is prepared from a nanoscale hexagonal ferrite composite material, a cobalt ferrite material and a cobalt-nickel bimetallic nano porous carbon material in a mass ratio of (3-5): (3-5): (1-2). The electromagnetic (EM) absorption performance of the material is greatly improved by finely regulating and controlling the particle size and morphology characteristics of the synthetic filler particles, and feasible theoretical and data support is provided for optimizing the performance of the electromagnetic shielding material, so that the application and development of the electromagnetic shielding material in wider fields are promoted.