47results about How to "Enhanced magnetic loss" patented technology

Belonging to the technical field of electronic materials, the invention relates to a microstrip antenna composite substrate material and its preparation method. The composite substrate material is formed by compounding 70-90 parts by mass of a main phase material and 10-30 parts by mass of an auxiliary phase material, wherein, the main phase material is a Co2Z hexagonal ferrite which has a molecular formula of Ba3-xSrxCo2Fe24O41 (with x located in the range of 0-1.5), and the auxiliary phase material is polypropylene resin. The preparation method consists of: 1) material weighing, mixing, first ball milling and drying; 2) presintering; 3) secondary ball milling and drying; 4) sintering; 5) tertiary ball milling and drying; 6) compounding and granulation; 7) thermoforming, etc. The composite substrate material has an isomagnetic dielectric property and low loss in a frequency scope of 300MHz-3GHz, and has certain flexibility at the same time. The preparation method in the invention is simple and easy to operate, and convenient for mastering and popularization. Employment of the composite substrate material as a microstrip antenna substrate is conducive to reduce microstrip antenna weight and volume, and is in favor of enhancing the bandwidth and radiation efficiency of microstrip antennas.

The invention relates to the technical field of microwave absorption, in particular to a graphene-based ternary composite wave-absorbing material and a preparation method thereof. The preparation method comprises the steps of firstly, preparing silicon dioxide-coated carbonyl iron core-shell composite particles by using a sol-gel method, then preparing graphite oxide by using an improved Hummers method, evenly dispersing the graphite oxide into dispersion liquid of the silicon dioxide-coated carbonyl iron core-shell composite particles, and finally, using an ultrasonic reduction method to enable graphite oxide to be reduced into graphene so as to prepare the graphene-based ternary composite wave-absorbing material. The preparation method provided by the invention is simple and efficient; the prepared composite wave-absorbing material is more excellent in wave absorbing performance, high in wave absorbing strength, wide in wave absorbing bandwidth and smaller in density compared with a pure carbonyl iron binary composite wave-absorbing material and a pure graphene and carbonyl iron or graphene binary composite wave-absorbing material; the graphene-based ternary composite wave-absorbing material also has regulation performance, and can realize strong wave absorption under different frequencies by adjusting the thickness of a coating layer SiO2, the mass ratio of graphene to the coated core-shell composite particles and the thickness of the ternary composite material.

The invention provides a preparation method of a three-dimensional ordered carbon-based porous wave-absorbing material based on native wood. The preparation method comprises the following steps: S1, cutting the native wood into cuboids with preset sizes, soaking the formed wood blocks for 1-2 days, repeatedly washing the wood blocks with deionized water multiple times, and finally drying the woodblocks at 50-70 DEG C; S2, putting the wood blocks dried in the step S1 into a tubular furnace, carrying out heating to 350-450 DEG C, and keeping the wood blocks at the temperature for 0.5-1 hour toobtain pre-carbonized charcoal blocks; S3, mixing the pre-carbonized charcoal blocks with Fe (NO3) 3 having a concentration of 0.05 to 0.2 mol/L, and carrying out drying at a temperature of 50 and 70DEG C; and S4, putting a product obtained after drying in the S3 into the tubular furnace, carrying out heating to a preset temperature, keeping the product at the temperature for 0.5-1 hour, and taking out a sintered product when the temperature decreases to room temperature, thereby obtaining the three-dimensional ordered carbon-based porous wave-absorbing material. The three-dimensional orderedcarbon-based porous wave-absorbing material obtained by using the method can be used as an excellent wave-absorbing material with light weight, small thickness, wide absorption frequency band and strong absorption characteristics.

The invention discloses an electromagnetic shielding rubber material. Conducting materials are uniformly distributed in rubber matrix. The electromagnetic shielding rubber material comprises the following components in parts by mass: 100 parts of rubber matrix, 20 to 30 parts of carbon black, 20 to 55 parts of nickel-plated carbon nanotubes, 5 to 15 parts of metal powder, 2 to 4 parts of sulphur,1 to 3 parts of a vulcanizing agent DCP, 1 to 2 parts of an accelerant TMTD, 1 to 2 parts of an accelerant CZ, 2 to 5 parts of a coupling agent KH-570, 1 to 2 parts of hydroxyl silicone oil, 2 to 4 parts of a plasticizer DBP, 2 to 5 parts of a dispersing agent, 0.5 to 1 part of an antiager TK-100, and 0.5 to 1 part of an antiager TK-101. The electromagnetic shielding rubber material is excellent in mechanical property and electrical and thermal conductivity, high in Electromagnetic shielding effectiveness, and medium in cost, and has excellent integrated quality.

The invention belongs to the technical field of absorbing materials and relates to absorbing agents, a preparation method, application and the absorbing materials of magnetic fluorocarbon materials. The preparation method includes: firstly, magnetic nanoparticles are loaded on carbon materials to prepare ferriferrous oxide @ carbon material composites, and then the ferriferrous oxide @ carbon material composites are fluoridized at 0-30 DEG C. The absorbing agents, the preparation method, the application and the absorbing materials of the magnetic fluorocarbon materials have the advantages that: on the one hand, the introduction of the ferriferrous oxide can increase the magnetism of carbon nanotubes; on the other hand, the ferriferrous oxide can improve the fluorination reaction activity of the carbon nanotubes; therefore, fluorinated carbon nanotubes with high fluorination degree can be prepared at lower temperature, thereby being beneficial to reduce the dielectric constant of the absorbing agents. Therefore, the magnetic fluorinated carbon nanotubes have high permeability and low dielectric constant to show good impedance matching, thereby having strong absorbing intensity and wide absorbing frequency band and meeting the requirements of 'light, thin, strong and wide' of novel absorbing materials.

The invention disclose a ferroferric oxide/polypyrrole composite material and a preparation method thereof. The collagen fiber adopted as a dispersion base is uniformly dispersed into nano ferroferricoxide, and in-situ polymerization is performed so as to generate polypyrrole adopted as a dielectric-type wave absorber for wrapping the collagen fiber, so that the problem that nano materials are easy to cluster is solved, and translation of the nano materials is prevented. The fiber material utilizes ferroferric oxide as a magnetic medium wave absorber and polypyrrole as the dielectric-type wave absorber so as to absorb attenuation electromagnetic waves together, and meanwhile, the magnetic loss dielectric loss performances of the collagen fiber are enhanced. The selected materials are extensive in source and low in cost; the preparation process is simple and environmentally friendly, and is low in equipment dependency degree, so that the preparation method is an effective way for preparing dual-functional ferroferric oxide/polypyrrole nano composite fiber materials.

The invention relates to the technical field of electromagnetic functional materials, in particular to soft magnetic nanocrystalline metal or alloy sheet-shaped particles with internal grain orientation and a microwave absorbing material. The soft magnetic nanocrystalline metal or alloy sheet-shaped particles with the internal grain orientation are obtained by taking spherical or spheroidic soft magnetic metal or alloy particles with a certain grain size as a raw material and carrying out wet ball milling or stirring milling. According to the invention, grain orientation is introduced into soft magnetic nanocrystalline metal or alloy absorbent particles, and the obtained soft magnetic sheet-shaped particles have significantly improved magnetic loss, especially at the frequency of 4 GHz orbelow, and can be used as a high-quality microwave absorbent to effectively improve the low-frequency and broadband absorption performance of the wave-absorbing material.

The invention relates to a preparation method of a CNTs/NiFe3O4 functional material, and belongs to the technical field of functional nano composite materials and environmental biology. The preparation method of the CNTs/NiFe3O4 functional material comprises the following specific steps: purifying and activating multiwalled carbon nanotubes; preparing CNTsFe3O4: preparing the CNTs/NiFe3O4 nano composite material. The CNTs/NiFe3O4 functional material prepared by the invention is used as an efficient biological catalytic material and a wave-absorbing material, has the characteristics of promoting oxidation-reduction reaction and electron transfer, is used as a stabilizer and a catalyst in sewage treatment anaerobic digestion reaction, can improve the methane yield and produce biomass energy,can play a role once being added, and has a good application prospect. The catalyst is good in dispersity in a reactor and uniform and consistent in reaction, and can be recycled to save the cost.

The invention discloses an electromagnetic shielding material with chemically plated iron modified carbon nano-tubes and a method for preparing the same, belonging to the technical field of nano-material preparation, wherein multi-wall carbon nano-tubes which are subjected to surface acidification pretreatment and pretreatment are added to chemical plating solution and every carbon nano-tube is covered with a metal iron layer with ferromagnetism by a chemical plating method, so that the magnetic property of the carbon nano-tubes is improved; therefore, the integrated application properties ofthe carbon nano-tubes are also greatly improved while the original excellent properties of the carbon nano-tubes are maintained; as a result, the carbon nano-tubes can be applied to nano-ferromagnetism research, high-density memories and electromagnetic shielding materials.

The invention belongs to the field of electromagnetic wave-absorbing materials and particularly relates to a high-magnetic-loss and wideband FeCo electromagnetic wave-absorbing material and a preparation method thereof. The preparation method comprises the steps of carrying out ultrasonic treatment on the raw materials of ferrous chloride and cobalt acetate in a mixed solution, and adding ammoniawater and a reducing agent, so as to generate solvothermal reaction, thus obtaining the FeCo electromagnetic wave-absorbing material. The preparation method has the advantages of short synthesis period, simple process flow and low cost; and the FeCo alloy wave-absorbing material prepared by virtue of the preparation method has high magnetic loss and wideband wave-absorbing performance.

The invention discloses a method for preparing a wave-absorbing material by means of wool fibers, and belongs to the technical field of wave-absorbing materials. The method comprises the steps that firstly, a surfactant and water are mixed, then nano ferroferric oxide is added, low-speed emulsification is adopted, then high-speed emulsification is performed, and an emulsified mixture is mixed with polyethylene glycol to obtain modified liquid; secondly, wool is smashed and carbonized, and then added into the modified liquid to be soaked, the ferroferric oxide is loaded on the surface of the carbonized wool, and modified wool is obtained for standby application; thirdly, manganese dioxide powder, a stabilizer, a complexing agent and sodium alginate are taken and added into deionized water, stirring mixing is performed, then nickel chloride hexahydrate is added, and stirring reaction is performed to obtain a sodium alginate gel fluid containing metal; and fourthly, the gel fluid and the modified wool are mixed, and then solidified after a calcium chloride solution is added dropwise, freeze drying is performed after solidification, and the wave-absorbing material can be obtained. The wave-absorbing material prepared through the method disclosed by the invention is low in density and wide in bandwidth range, all electromagnetic waves can be fast attenuated by means of the wave-absorbing material of the material composition and structure, and wide application prospects are achieved.

The invention discloses a flake like ceramic wave absorbing material and a preparation method thereof. The chemical formula of the wave absorbing material is Ba<12-x>R<x>Fe<28>Ti<15>O<84>, 2<=x<=4, and R represents rare earth elements: La or Nd. The wave absorbing material is layered oxide having a monoclinic crystal structure, the space group is C2/m; the monoclinic crystal structure is randomlydistributed sheet shaped or flake like grains, the diameter is 2 to 7 [mu]m, and the thickness is 1 to 2 [mu]m. The invention also provides a preparation method of the wave absorbing material. The preparation method comprises following steps: (1) preparing sol; (2) preparing primary powder; and (3) preparing the waving absorbing material. Due to the sheet/flake like microstructure feature of the wave absorbing material, after the wave absorbing material is doped and modified by magnetic elements, the wave absorbing material has an excellent electromagnetic loss feature and a good microwave impedance matching characteristic; moreover, the wave absorbing material has a good microwave absorbing feature in a range of 2 to 18 GHz; the optimal reflection loss is lower than -17 dB, the reflectionloss is lower than -10 Db, and the frequency band width is greater than 4.0 GHz.

The invention discloses an oriented honeycomb wave-absorbing material and a preparation method thereof, and belongs to the technical field of electromagnetic wave functional materials. The preparation method comprises the following steps: (1) dipping treatment of a honeycomb base material: dipping the honeycomb base material in magnetic absorbent slurry to obtain a honeycomb material coated with a magnetic wave-absorbing coating; and (2) orientation and molding of the honeycomb material: rotating the honeycomb material coated with the magnetic wave-absorbing coating in a magnetic field for 6-12 hours, and then heating and curing to obtain the oriented honeycomb wave-absorbing material. An impregnation method and a magnetic field induction method are combined, on the basis of an existing honeycomb structure wave-absorbing material, the spatial arrangement of the absorbent on the honeycomb wall is changed by applying a magnetic field, the orientation degree of the absorbent is improved, the obtained honeycomb material has remarkably improved magnetic loss, and especially in a P frequency band, and the low-frequency absorption performance of the wave-absorbing material is effectively improved.

The invention discloses a preparation method and application of a tremella derived carbon-based magnetic particle loaded wave-absorbing material. Tremella is taken as a raw material of the wave-absorbing material, magnetic particles are absorbed by swelling foaming to enter the inside of the tremella, the tremella derived carbon-based magnetic particle loaded wave-absorbing material is prepared through freeze drying and one-step carbonization, and a simple, green and low-cost preparation method is provided. By simply controlling the concentration of metal ions, the regulation and control of microstructures such as a pore structure and a layered structure can be realized, and meanwhile, the coexistence of magnetic loss and dielectric loss of the material is realized. By using a freeze-drying technology, the inherent hierarchical structure and nanopore structure of tremella can be reserved, and metal ions are fixed at initial positions, so that the absorption performance of the tremella derived wave-absorbing material can be improved. The special structure endows the wave-absorbing material with the characteristics of small thickness, light weight and strong absorbing capacity.

The invention relates to an RFID antenna, an RFID label and an RFID antenna manufacturing method, wherein the slurry of the RFID antenna is nickel slurry. The nickel slurry satisfies the conditions described as follows: viscosity is 85-115Pa*s; linear resolution is lower than 200 [mu]m; resistivity is lower than 80 m[omega]/Sq; and an adhesion force is higher than or equal with 625N/cm<2>. The RFID antenna, the RFID label and the RFID antenna manufacturing method have advantages of reducing RFID antenna cost, saving energy and reducing emission.