1584results about How to "Improve absorbing performance" patented technology

The invention discloses a composite polymethacrylimide foam wave absorption material which is prepared by the following steps: (1) performing surface treatment on a wave absorber, namely uniformly mixing the wave absorber and a surfactant with a solvent, ultrasonically processing, drying to remove the solvent, and breaking and grinding to obtain a wave absorber subjected to surface treatment; (2) preparing expandable polymethacrylimide resin particles; (3) preparing the composite polymethacrylimide foam wave absorption material. The material is good in wave absorption performance, heat resistance and mechanical property, can be used for avoiding the defects of complex process, material waste and the like caused by a process that the material is machined to obtain a complex shape, can absorb electromagnetic waves to prevent electromagnetic wave interference, can be applied to the aspects of medical appliances, household appliances, electronic products, high-rise buildings, communication equipment, measurement equipment and the like, also can be used for stealth of various aircrafts, and has wide application prospect in the civil or military field.

The present invention provides a nano-graphite alkenyl composite wave-absorbing material and method of preparing the same. The wave-absorbing material includes graphite alkenyl and nanoparticle deposition material which is metal or metallic oxide; the weight percentage of the graphite alkenyl is 15-95%, the weight percentage of the nanoparticle deposition material is 5-85%, the metal or metallic oxide nanoparticle is deposited on the graphite alkenyl surface and between the layers, prepared by the metal salt and graphite alkenyl in the electrodeposition pattern. The nano-graphite alkenyl composite wave-absorbing material is provided with stable capability, thin thickness, low density, corrosion resistant, simple manufacture, good wave-absorbing capability and favourable application foreground.

The invention discloses a radar and infrared compatible stealthy material and a preparation method thereof. The compatible stealthy material is mainly formed by compounding a radar wave absorbing structural layer and an infrared stealthy functional layer, wherein the radar wave absorbing structural layer is made of a glass fiber reinforced glass steel composite material; and the infrared stealthy functional layer is a capacitive frequency selective surface. The preparation method comprises the following steps of: preparing the capacitive frequency selective surface by a printed circuit board (PCB) process; preparing a layer of resistance sheet on glass fiber plain cloth by using conductive carbon slurry through a screen printing process; preparing the glass fiber reinforced glass steel composite material by using epoxy resin as a base material and the glass fiber plain cloth as a reinforcing material through a resin forming process; and curing to make the capacitive frequency selective surface compounded and superposed so as to obtain the radar and infrared compatible stealthy material. The compatible stealthy material has a simple structure and low cost, is convenient to prepare, and has the duplex characteristics of high reflection of an infrared wave band and high permeation of a radar wave band.

The invention relates to a method for preparing a reduced graphene oxide / ferroferric oxide nano-grade wave-absorbing material. With the method, the RGO-Fe3O4 composite wave-absorbing material can be easily and rapidly produced with large scale. The RGO-Fe3O4 composite wave-absorbing material is prepared with one step with a simplified co-precipitation method. The preparation method is simple and fast, and assists in realizing large-scale production. The prepared composite material has good wave-absorbing performance. Through the adjustment upon the ratio of RGO and Fe3O4 and the thickness of the composite material, effective absorption of different wave bands can be realized.

The present invention belongs to the field of radiation resisting technology, and is especially one kind of nanometer wave absorbing fiber. The nanometer wave absorbing fiber consists of nanometer wave absorbing particle of 1-100 nm diameter of fine fiber of 30-2000 nm diameter in the weight ratio of 3-35 to 65-97. The nanometer wave absorbing fiber has wide wave absorbing range, powerful wave absorbing capacity, lasting wave absorbing effect and high flexibility. It has wave absorbing function, as well as antistatic, bacteriostasis, biochemical protection and other functions.

The invention discloses a foam metal-graphene composite material and a preparation method thereof. The composite material comprises a foam metal substrate and a graphene film layer positioned on the substrate. The foam metal-graphene composite material is prepared by means of electrophoresis. Specifically, the preparation method comprises the following steps: removing greasy dirt and oxides from the surface of a foam metal substrate, preparing graphene by the oxidation-reduction method, modifying graphene, and performing electrophoretic deposition on the graphene on the surface of the foam metal substrate. Within a certain of electromagnetic waveband, on one hand, the foam metal-graphene composite material has the structural advantages of light weight and porosity, large specific surface area and good conductivity of a foam metal, and on the other hand, the composite material integrates excellent electrical conductivity and high dielectric constant, a capacity of being more conducive to absorbing electromagnetic waves due to a large amount of defects and functional group residues of the self-made graphene, and other properties of self-made graphene. The composite material has a higher electromagnetic shielding performance and can serve as an excellent electromagnetic shielding material.

The invention discloses a bimetallic-organic-framework-based derived porous carbon / multi-wall carbon nanotube nano composite absorbing material and a preparation method thereof. On the basis of a hightemperature pyrolysis method, the porous carbon / multi-wall carbon nanotube nano composite material is prepared by using a multi-wall carbon nano tube as a carrier, cobaltous nitrate hexahydrate and zinc nitrate hexahydrate as metal salt precursors, 2-methylimidazole as an organic ligand, and methanol and ethanol as mixed solvents. The preparation method has good green and environment-friendly effects; no hazardous by products are generated; and the preparation process is simple. The prepared nano composite material has advantages of high electromagnetic wave absorption capacity, large absorption frequency bandwidth and low density. Electromagnetic wave with different wavebands can be absorbed effectively by adjusting the additive amount of the multi-wall carbon nano tube and the coating thickness. The bimetallic-organic-framework-based derived porous carbon / multi-wall carbon nanotube nano composite absorbing material and the preparation method thereof have the great application valuein the electromagnetic absorption and electromagnetic shielding fields.

The invention discloses a preparation method of a graphene composite aerogel absorbing material and application thereof. The material is obtained by one-step reduction self-assembled reaction on reduced graphene oxide, a polymer A and magnetic nano particles which wrap a polymer B. The absorbing material is low in density and high in absorbing strength, effectively absorbs bandwidth, and has excellent absorbing property on an X wave band. In the absorbing material, the content of graphene is low, the cost is low, and therefore, the graphene composite aerogel absorbing material has wide application potential and market prospect in the field of invisibility of aircrafts, electromagnetic shielding of radar and communication equipment, and electromagnetic safety protection.

The invention relates to a sandwich structure wave-absorbing composite material and a preparation method thereof, an integrated sandwich structure comprises an intermediate layer, an upper skin and alower skin, the intermediate layer is a honeycomb material filled with carbon nanotube / cellulose wave-absorbing foam, the upper skin is a quartz fiber cloth reinforced resin material having electromagnetic wave transmission characteristics, and the lower skin is a carbon fiber cloth-reinforced resin material having electromagnetic wave reflection characteristics. Specifically, the preparation method is carried out according to the following steps: 1. the intermediate layer, namely the honeycomb material filled with the carbon nanotube / cellulose wave-absorbing foam is prepared by a freeze-drying method; 2. the upper kin and the lower skin are prepared by impregnating resin with quartz fiber cloth / carbon fiber cloth; and 3. the intermediate wave-absorbing layer is compounded with the upper kin and the lower skin. The sandwich structure wave-absorbing composite material prepared by the method can replace existing wave-absorbing materials, and is widely used in aircrafts, ground weapon equipment, surface ships and other parts that have stealth requirements for electromagnetic waves.

The present invention belongs to the field of aluminum-base material in metallurgical technology, and is especially aluminum-base wave absorbing material and its preparation process. The present invention features that aluminum or aluminum alloy plate is treated first through one-step or two-step DC or AC anode oxidation process to form aluminum-base porous alumina template, or AAO template, with porous alumina film in the surface; and the template is then DC or pulse current electrochemically deposited to assemble nanometer magnetic metal wire array in the AAO porous film, so as to make the aluminum-base wave absorbing material with in-situ assembled nanometer magnetic metal wire array in the surface. The present invention has close combination between the wave absorbing material and the substrate and high wave absorbing effect caused by the coupling effect and the size effect of the nanometer wire array. The present invention may be used widely in stealth and electromagnetic shield.

The invention discloses a novel corrosion resistant composite wave absorbing material and a preparation method thereof, and belongs to the field of electromagnetic wave absorbing materials. The wave absorbing material includes 60-100 parts of resin polymer matrix, 50-100 parts of a curing agent, 20-30 parts of ferrite, 20-30 parts of carbonyl iron powder and 5-10 parts of a hollow granular material. The preparation method is as follows: adding a magnetic filler, a conductive filler and a semi conductive filler into resin solution for evenly mixing, and adding the curing agent. The electromagnetic wave absorbing material prepared by the method has the coating thickness of less than or equal to 3mm; in the 2-18GHz, the absorption reflectivity is less than or equal to-10dB; and the electromagnetic wave absorbing material is stealth material with good corrosion resistance, strong wave absorbing performance and wide wave absorbing band.

The invention brings forward a broadband wave absorbing material with stable polarization, for solving the technical problems of poor polarization stability and not wide low-band bandwidth existing in a conventional wave absorbing material. The broadband wave absorbing material comprises a wave absorbing structure (1), an upper medium plate (2), a foam layer (3), a lower medium plate (4) and a frequency selection surface (5), wherein the wave absorbing structure (1) is printed on the upper surface of the upper medium plate (2), the frequency selection surface (5) is printed on the lower surface of the lower medium plate (4), the upper medium plate (2), the foam layer (3) and the lower medium plate (4) are successively arranged to form an up-down stacked structure, the wave absorbing structure (1) is formed by periodically arranging M*N metal broken line units (11) of dead square structures, and the frequency selection surface (5) is formed by periodically arranging M*N frequency selection surface units (51). The polarization stability is high, the absorption frequency band width is wide, the wave absorbing feature is high, the transmission feature at a high frequency is good, and the broadband wave absorbing material with stable polarization can be applied to such fields as antenna communication and absorption shielding and the like.

The invention relates to a preparation method for wave-absorbing foam concrete. The preparation method comprises the following step of mixing cement, a physical foaming agent, a wave absorbing agent, a polycarboxylic-acid high-efficiency water reducing agent and water. The preparation method is characterized in that the wave absorbing agent is metal powder, ferrite, fiber, carbon black, crystal whisker or carbon nano tube, wherein the wave absorbing agent and water are mixed according to the mass ratio of 1-40:60-100. The wave-absorbing foam concrete is prepared by premixing the wave absorbing agent by an internal mixing method, mixing uniformly, adding foam and stirring, casting and molding and curing. The wave-absorbing foam concrete has the characteristics of simple molding process, low material density and good wave-absorbing performance.

The invention provides a high-property absorption and wave absorption type catalyst for VOCs (Volatile Organic Chemicals) catalytic oxidation. The high-property absorption and wave absorption type catalyst has a structural formula: a Cu-Mn-Ce / TiO2-molecular sieve or a CNDs-Cu-Mn-Ce / TiO2-molecular sieve, wherein CNDs serve as a modifier; Cu and Mn serve as catalytic activity components; Ce serves as a promoted catalytic metal; a TiO2-molecular sieve serves as a carrier. The invention further provides a preparation method of the catalyst. According to the catalyst and the preparation method of the catalyst provided by the invention, the treatment cost is greatly reduced and energy is utilized at maximum through the advantages of the combination of a plurality of materials, so that the relatively good VOCs catalytic oxidation effect can be realized under the microwave irradiation.

The invention provides a composite wave absorbing material. The material comprises a metal magnetic nano material and a matrix material; and the metal magnetic nano material is uniformly dispersed in the matrix material. The invention also provides a preparation method for the composite wave absorbing material, which comprises the following steps of: 1) preparing the metal magnetic nano material; and 2) uniformly dispersing the metal magnetic nano material into the matrix material to prepare a coating or a film material. The composite wave absorbing material has the advantages of strong wave absorbing capability, wide wave absorbing band, good heat dissipation performance, light mass and the like.

The invention discloses a novel light-wave absorbing carbon fiber composite material preparation method which comprises, subjecting cellulose viscose to carbonization and activation, obtaining active adhesive based carbon fiber, making the active carbon fiber to 5-50mm short carbon fiber, charging into bisphenol type A epoxy resin, mixing homogeneously, mixing with low-molecular-weight polyamide curing agent, finally agitating homogeneously and hot-setting.

This invention relates to an electromagnetic wave absorption material, which is a high molecular compound material compounded by mixing a polymer matrix of two phases or more than two and an electromagnetic wave absorbent, in which, the polymer matrix is composed of two or more than two kinds of incompatible polymers and the material has fine wave absorption performance.

The invention relates to a preparation method of waterborne electromagnetic shielding coating. According to the formulation, the waterborne electromagnetic shielding coating is prepared from, by weight, 10.0-60.0 parts of water, 0.1-0.3 part of wetting agents, 0.4-0.8 part of dispersant, 0.1-0.3 part of defoamer, 0.7-1.3 parts of anti-freezing agents, 0.2-0.5 part of pH modifier, 20.0-60.0 parts of electromagnetic shielding additives, 0.5-2.0 parts of thickener, 25.0-40.0 parts of acrylic emulsion, 0.8-1.3 parts of coalescing agents, 0.2-0.4 part of preservative, 0.3-0.6 part of mould-proof anti-alga agents and 0.1-0.3 part of theological additives. The preparation method has the following advantages that the waterborne electromagnetic shielding coating prepared from graphene / nano ferrite, zinc oxide whiskers, nano silicon carbide, nanometal nickel powder and other materials has the advantages of being light, wide in frequency band, excellent in shielding performance, safe, environmentally friendly and the like, and the requirements of the electromagnetic shielding materials for impedance matching are met.

The invention discloses a preparation method for a Ti<3>C<2>Mxene / polymer composite wave-absorbing material. The high-efficiency Ti<3>C<2>Mxene / polymer composite wave-absorbing material is prepared by using a solution etching method and a compounding method. The Ti<3>C<2>Mxene / polymer composite wave-absorbing material prepared in the invention has low density, high strength and an adjustable dielectric constant; and more importantly, the composite material can both absorb and reflect electromagnetic waves, so secondary pollution of electromagnetic waves to environment is reduced. The Ti<3>C<2>Mxene / polymer composite wave-absorbing material has the characteristics of light mass, thin thickness, high strength and good wave-absorbing performance and has good application prospects.

The invention discloses a carbonized bacterial cellulose / magnetic composite wave-absorbing material. The carbonized bacterial cellulose / magnetic composite wave-absorbing material is characterized in that: the material is formed by compounding carbonized bacterial cellulose and a nano-magnetic material, the volume ratio of the carbonized bacterial cellulose to the nano-magnetic material is between 1:20 and 5:1, and the nano-magnetic material is one of ferrite or magnetic metal and alloy thereof. The carbonized bacterial cellulose and the nano-magnetic material are compounded, and an obtained biomass mesh-shaped nano-carbon fiber / magnetic composite material can be taken as an ideal microwave absorbent; the wave-absorbing material has the characteristics of thinness, lightness, width and strongness; the carbonized bacterial cellulose / magnetic composite wave-absorbing material has the advantages of low cost, simple preparation technology, environment-friendliness and the like; and the composite wave-absorbing material has broad application prospect in the field of electromagnetic pollution prevention, radar stealth and the like.

Belonging to the technical field of high polymer materials, the invention relates to a thermoplastic resin prepreg tape and preparation method thereof. The thermoplastic resin prepreg tape comprises the following components by weight: 30-80% of thermoplastic resin; 10-60% of a fiber; 0.5-3% of a compatilizer; 0.2-0.5% of an antioxidant; 0.3-2% of a lubricant; and 1-40% of a wave-absorbing material. In the invention, mainly the wave-absorbing material is added to the prepreg tape so as to make the continuous fiber reinforced thermoplastic resin prepreg tape have a wave-absorbing property. The continuous fiber reinforced thermoplastic resin prepreg tape has high strength and a wave-absorbing property at the same time, and can be applied to anechoic chambers, microwave communication, electronic equipment, medical equipment and other fields, thus enhancing product competitiveness and expanding application scope.

The invention relates to a method for preparing a reduced-oxidized graphene / Fe3O4 / Ag nano composite wave-absorbing material. The method comprises the following steps: preparing GO / Fe3O4 by using a simplified coprecipitation method, and preparing the RGO / Fe3O4 / Ag ternary composite material by employing a wet chemical reducing method. The preparation method is simple and rapid, large-scale production can be realized, the prepared composite material is good in wave-absorbing performance, and different wave bands can be effectively absorbed by adjusting the ratio of RGO to Fe3O4 to Ag, the amount of the reducing agent and the thickness of the composite material.

The invention relates to a composite fiber material, and the combination contains polyacrylonitrile carbon 80-96, nano silicon carbide 4-20%; nickel powder is 6-20% of the fiber in weight, assistant 5-8%. The steps: making ultrasonic wave vibration, mixing and extrusion on silicon carbide, polyacrylonitrile carbon and assistant to produce compound particles; making copolymerization and commixture on copolymerizable monomer to make polyacrylonitrile carbon wave absorbing fiber; spinning silicon carbide / nickel fiber; making preoxidation, carbonization, graphitization, surface nickel processing and weaving on the spinning to obtain the finished product. It has wide screened wave bands, and high electromagnetic wave absorbing rate, has no secondary pollution. It shortens working procedure, reduces cost, and has the characters of high strength, high modulus, low expansion coefficient, etc.

The invention relates to the field of microwave ovenware coatings, and discloses a coating which comprises a wave-absorbing material and an adhesive, wherein the adhesive is at least one of titanium dioxide sol, silicon dioxide sol, aluminum oxide sol and silicon-aluminum sol. The invention further discloses a preparation method of the coating. The preparation method comprises the following step: in the presence or absence of an additive, mixing the wave-absorbing material with the adhesive. In addition, the invention discloses an application of the coating in preparing microwave ovenware. As the sol is taken as the adhesive, dispersion of the wave-absorbing material can be improved, a thinly coated layer without resin and an ovenware coating which is good in wave absorbing property and antibacterial property can be prepared, problems (that is, when a conventional ovenware wave-absorbing material is used at a relatively high temperature, harmful substances can be easily generated, the conventional ovenware wave-absorbing property and antibacterial property are poor, the appearance attractiveness can be affected and the like) of the conventional ovenware wave-absorbing material can be comprehensively solved, relatively good product experience can be brought to an ovenware user, and thus more and more customers are willing to make baked and barbecue food by using the ovenware.

The invention discloses a grapheme and ultra surface based working bandwidth adjustable wave absorber and mainly solves technical problems of non-adjustable bandwidth and poor wave absorbing performance of a prior wave absorber. The working bandwidth adjustable wave absorber provided by the invention includes a DC power source, and a frequency selecting surface, a three-layer dielectric substrate and a metal substrate arranged from top down in a successively overlapping manner. Air medium is arranged between the second dielectric layer, so that the wave absorbing bandwidth is expanded. The frequency selecting surface is composed of m*n dumb-bell shaped cycle units. Each of the upper end and the lower end of each dumb-bell shaped unit is provided with metal pasters connected by vertical metal leads and provided with grapheme film sandwich layers. A horizontal metal fine lead penetrates through each whole line of the dumb-bell shaped unit and achieves the serial connection of the dumb-bell shaped units. The working bandwidth adjustable wave absorber provided by the invention is simple in structure. By using the metal pasters provided with the grapheme film sandwich layers, the wave absorbing performance is good, so that the wave absorbing bandwidth can be tuned more conveniently. By adopting the metal substrate with high electricity conductivity, electromagnetic wave transmission of the wave absorber is reduced. The working bandwidth adjustable wave absorber provided by the invention is suitable for electromagnetic immunity and modern communication systems.

The invention relates to a near shape preparation method of multiphase ceramic Si3N4-SiC, which completes component molding directly by bonding between particles through a three-dimensional printing method, needs no dies, and is capable of molding components with complex shapes. The Si3N4-SiC multiphase ceramic prepared by 3DP combined with PIP methods solves the problem of nonuniformity of CVI methods, and SiC nanocrystallines and SiC nanowires are uniformly distributed in a Si3N4 substrate. The Si3N4-SiC composite ceramic which is continuous, compact, free of impurities, good in uniformity and stable in wave absorbing property is obtained by using Si3N4 powder and polycarbosilane as raw materials through steps of three-dimensional printing, sintering, dipping, curing, cracking and heat treatment.

The invention discloses a Ni-based alloy magnetic microwave absorbing material and a preparation method thereof. The stoichiometric proportions of a molecular formula of the magnetic microwave absorbing material are as follows: 16.67% of Pr, 83.33%-75% of Ni and 0-8.33% of Fe. The Ni-based alloy magnetic microwave absorbing material is prepared by the following main steps: smelting Pr, Fe and Ni metals, of which the purities are greater than or equal to 99.50% as raw materials under argon or vacuum protection; carrying out heat treatment on a cast ingot at 600-1100 DEG C under vacuum or argon protection; quenching with ice water; and grinding into powder and carrying out ball milling to form powder after mechanically crushing. The Ni-based alloy disclosed by the invention has the advantages of relatively good microwave absorbing effect, wide absorbing frequency band, simple preparation process, high antioxidant resistance and the like in a 2-18GHz of microwave band; and the Ni-based alloy magnetic microwave absorbing material disclosed by the invention is suitable for preparation of microwave absorbing products of requiring wide absorbing frequency band, good wave absorbing property and high corrosion resistance in the magnetic wave absorbing material.

The invention discloses a ferroferric oxide@carbon / reduced graphene oxide nano composite wave-absorbing material and a preparation method thereof. By using graphene oxide as a template, ferric chloride hexahydrate as a metal salt, terephthalic acid as an organic ligand, and N,N-dimethylformamide as a solvent, the ferroferric oxide@carbon / reduced graphene oxide nano composite material is prepared by a solvothermal-high temperature pyrolysis two-step method. The preparation method is environmentally friendly, generates no toxic by-products, and has a simple preparation process. The prepared nanocomposite material has a good microwave absorption capacity, a wide absorption frequency band, a low thickness, light weight and a low filling ratio, can absorb electromagnetic waves in different wavelength bands by adjusting the addition amount of graphene oxide in a precursor and the thickness of a coating layer, and has an important application value in the field of electromagnetic absorptionand electromagnetic shielding.

The invention provides a wave absorbing body structure comprising a metal base plate and an electrical loss body covering one surface of the metal base plate. Since the electrical loss body has a high dielectric loss, the wave absorbing body structure of the present invention has a good wave absorbing effect in a wide frequency band compared with the absorbing performance of the wave absorbing material of a conventional low-loss multi-layer wave absorbing honeycomb. With the structure of the invention, not only the wave absorbing performance can be increased, but also a low surface density can be achieved for the structure due to the reduced overall thickness of the structure; accordingly, the wave absorbing body structure can be applied in fields requiring bearing and weight reducing.

The invention relates to a fire-retardant type wide-frequency-band high-power compound wave-absorbing material and a preparing method thereof. The material comprises an outer shell, an inner core and a base, wherein the outer shell is a polyhedron formed by a set of pyramids arranged side by side, the wedges of the pyramids are towards the same side, the inner core is located inside the outer shell, the base is located at the bottom of the outer shell, the outer shell is made of non-woven cloths, the inner core and the base are made of polyurethane foams, the inner surface and the outer surface of the outer shell are respectively provided with a first fire-retardant wave-absorbing agent layer in a coating mode, and the inner core and the base are immersed in second fire-retardant wave-absorbing agents. Both the first fire-retardant wave-absorbing agents and the second fire-retardant wave-absorbing agents comprise acetylene black, alpha-SiC, aluminum hydroxide, kaolin, pentaerythritol, and App-3. The corresponding preparing method comprises the steps of preparing the outer shell, preparing the inner core and the base, and inserting the inner core into the outer shell, and therefore the wave-absorbing material is obtained. The wave-absorbing material has good wave absorbing performance and fire retardance, and the preparing method is simple and easy to implement.