84 results about "Vacuum Assistance" patented technology

The invention discloses a vacuum-assisted pultrusion preforming device for a composite material. The vacuum-assisted pultrusion preforming device comprises a yarn threading plate, a gum dipping tank, a gum extruding roller and a vacuum-assisted preforming mold which are sequentially arranged in the pultrusion direction, wherein fiber bundles penetrate through the yarn threading plate in a layered mode, the gum dipping tank is used for containing resin, and the gum extruding roller is used for extruding redundant resin. The vacuum auxiliary preforming mold is provided with a preforming mold cavity, a vacuum cavity is formed in one section of the preforming mold cavity of the vacuum auxiliary preforming mold, an air exhaust hole is formed in the upper portion of the vacuum cavity, and a semi-permeable membrane allowing gas to pass through but blocking resin to pass through is arranged at the air exhaust hole. And the air exhaust hole is externally connected with a vacuumizing device. The vacuum-assisted pultrusion preforming device can effectively discharge microbubbles in resin and fiber bundles, effectively control uniform distribution of the content of the resin and remarkably promote full infiltration of high-viscosity resin to fibers.

The invention relates to the technical field of composite materials with textile structures, in particular to a preparation method of a three-dimensional warp-direction interlocking woven composite material with different reinforced structures, which comprises the following steps: firstly, carrying out straightening treatment on aramid fibers, and adopting the aramid fibers as warp and weft yarns, weaving a three-dimensional warp-direction interlocking woven fabric preform on a three-dimensional rapier loom controlled by a computer; preparing a resin matrix from epoxy resin, a reactive diluent and a polyether amine curing agent; carrying out vacuum-assisted resin transfer molding on the woven aramid fiber three-dimensional warp-direction interlocking woven fabric; and the three-dimensional warp-direction interlocking woven composite material with different reinforced structures is prepared by regulating and controlling a stacking mode. Through fiber low-damage weaving, structure regulation and control design and orthogonal interlocking lamination, the problems of layering sensitivity and anisotropy of the three-dimensional warp-direction interlocking woven composite material under the extreme load can be solved, and technical support is provided for achieving the excellent mechanical property, low-damage manufacturing, low cost and light weight of the three-dimensional woven composite material.

The invention belongs to the technical field of electromagnetic shielding and thermal management materials, and particularly relates to an electric insulation aramid nanofiber electromagnetic shielding composite film and a preparation method thereof. The composite film comprises an ANF layer, an LM-coated AgNWs conductive layer and a PDMS electrical insulation layer which are stacked in sequence, and the multifunctional composite film with high conductivity, high thermal conductivity, excellent electromagnetic shielding performance and electrical insulation is constructed through vacuum-assisted suction filtration, hot pressing and blade coating processes. The electromagnetic shielding effectiveness of the composite film in the X wave band reaches up to 92 dB, the volume resistivity exceeds 1 * 10 < 15 > omega.cm, and the composite film has good mechanical strength, flexibility and environmental stability and is suitable for electromagnetic protection and thermal management in electronic packaging, flexible electronics and extreme environments.

The invention discloses a bacterial cellulose / silver nanowire / MXene composite conductive film and a preparation method thereof, and relates to the technical field of flexible conductive materials. The composite film comprises a bacterial cellulose substrate, an MXene conductive layer and a silver nanowire conductive network layer. The preparation method comprises the following steps: S1, preparing bacterial cellulose dispersion liquid; s2, preparation of an MXene dispersion liquid; s3, preparing a silver nanowire dispersion liquid; and S4, preparing the composite film. The composite film with a Janus structure is prepared through a vacuum-assisted layer-by-layer filtering process, and the composite film has high mechanical performance, low square resistance, excellent electromagnetic interference shielding effectiveness, rapid Joule heating performance and excellent environmental stability and mechanical durability. The problem that an existing flexible electromagnetic shielding material is difficult to consider ultrathin performance, high flexibility, strong mechanical performance and multifunctional integration is solved, and the flexible electromagnetic shielding material has wide application prospects in the fields of electromagnetic shielding, flexible electronic devices, wearable heaters and the like.

The application provides a polydicyclopentadiene / glass fiber felt composite material and a preparation method thereof. The method comprises the following steps: step (1): laying a glass fiber felt on a glass plate, sequentially laying a release cloth, a flow guide net and a vacuum bag, and performing vacuum pumping and pressure maintaining; step (2): pouring a cyclic olefin liquid into the vacuum bag in step (1), performing stage temperature rising and curing, and releasing a polydicyclopentadiene / glass fiber felt composite material. The cyclic olefin liquid is configured as follows: A1, uniformly mixing 100 parts by mass of DCPD and 5-20 parts by mass of a TCPD system to prepare a mixed solution; wherein the TCPD system comprises 10wt% of TCPD and 90wt% of DCPD; A2, dissolving 0.02-0.06 parts by mass of a Grubbs second-generation catalyst and 0.002-0.006 parts by mass of a retarder in 1-2 parts by mass of a high-boiling-point silane coupling agent, and adding the mixture into the mixed solution in step A1 to prepare a liquid. The method adopts a vacuum-assisted resin infusion molding (VARI) technology, has the characteristics of simple operation and rapid reaction, and the obtained composite material has high mechanical properties.

The utility model relates to battery package airtightness detects the field of inflation, especially based on the quick airtightness detection inflation device of battery package of vacuum auxiliary. The utility model provides a kind of to seal between sealing cover and detection box while closing sealing cover, avoid the formation of poor sealing interference vacuum environment based on the quick airtightness detection inflation device of vacuum auxiliary of battery package. A kind of quick airtightness detection inflation device of battery package based on vacuum auxiliary, including base and first electric guide rail etc., base left and right two parts upper side are connected with first electric guide rail. The utility model passes through sealing extrusion block extrusion connecting rod, drives connecting rod rotation, so that connecting rod extrusion damper, while connecting rod rotates, extrusion push plate and move sealing extrusion block inward, so that push plate and sealing cover contact and seal, reach to seal between sealing cover and detection box while closing sealing cover, avoid the formation of poor sealing interference vacuum environment effect.

The present application relates to a kind of blended fabric segmented steaming fixation method, comprising the following steps: blended fabric is sequentially carried out desizing, kiering, bleaching and mercerizing treatment, and pretreatment blended fabric is obtained after drying;Using composite reagent on pretreatment blended fabric is carried out padding treatment or vacuum-assisted foam impregnation treatment, and pre-treatment blended fabric is obtained after hot air drying;Prepare dye liquor, and after using dye liquor on pre-treatment blended fabric is carried out dye liquor padding treatment, then carry out segmented steaming fixation treatment, and after sequentially washing, drying, setting, obtain dyed blended fabric.The present application uses the composite reagent containing Ageratina pichurini ethanol extract and simmondsia chinensis seed oil to carry out padding treatment or vacuum-assisted foam impregnation treatment on blended fabric before dyeing, then carries out segmented steaming fixation treatment, can significantly improve the tensile strength and wash fastness of blended fabric, while giving blended fabric good gloss, and can make blended fabric keep better perspiration fastness.

The invention relates to the technical field of anti-fouling surface treatment of a microstructure of a grating injection molded part, and discloses an anti-fouling surface treatment method of a microstructure of a highlight grating injection molded part, which comprises the steps of mold microstructure processing, vacuum-assisted injection molding, rapid cooling and stress release, surface pretreatment, plasma activation treatment, nano hydrophobic coating spraying and quality detection. By means of the treatment method, the highlight visual effect can be kept while the anti-pollution effect of the grating injection molding part is improved.

The invention belongs to the technical field of thermal spraying coating hole sealing, and discloses a hole sealing method based on the porosity of a thermal spraying coating, which comprises the following steps: forming a coating on the surface of a base material through a thermal spraying process, applying hole sealing glue on the surface of the coating, and forming a hole by utilizing the structural characteristic that open pores are communicated with one another. Enabling the hole sealing glue to naturally permeate into the coating under the action of gravity, enabling the hole sealing glue to at least permeate into the coating by 500 microns before curing by controlling the surface tension, viscosity and curing conditions of the hole sealing glue, and continuously filling holes; and then the coating is subjected to low-temperature curing treatment, so that the hole sealing glue forms a stable hole sealing structure in the holes. After the method disclosed by the invention is adopted, no less than 95% of open pores in the coating can be effectively sealed under the condition of not applying external pressure or vacuum assistance, so that the voltage resistance of the thermal spraying coating is stabilized at 500V or above, and the resistance value is improved from megohm level to gigaohm level, thereby obviously improving the electrical property and corrosion resistance of the coating.

The application belongs to the field of new material membrane separation, and relates to a COF / MXene composite membrane and a preparation method and application thereof. x nanosheet dispersion solution to obtain an Mxene solution; (2) a TpPa-SO3H nanosheet solution is prepared to obtain a COF solution; (3) the TpPa-SO3H nanosheet solution is first deposited on a nylon porous base membrane through vacuum-assisted self-assembly to form an intermediate porous COF layer, and then the Ti3C2T x nanosheet dispersion solution is deposited on the COF layer to prepare the COF / MXene composite membrane. The preparation method is simple in operation and high in repeatability, and the obtained composite membrane has excellent separation performance and can efficiently separate organic pollutants such as dyes in water.

The application discloses a kind of preparation methods of high-performance alumina fiber reinforced ceramic matrix composite, including preparation alumina fiber fabric, preparation magnesium aluminate spinel aqueous sol, preparation composite material: magnesium aluminate spinel aqueous sol is brushed on alumina fiber fabric, and after surface drying, it is laminated hot-pressing to its prepreg, then put into muffle furnace and sintered, after cooling to 25 DEG C, obtain the initial alumina fiber ceramic composite material, the alumina fiber ceramic composite material is placed in vacuum assisted impregnation device vacuum assisted impregnation, then put into oven and dried, repeat sintering-vacuum assisted impregnation-drying step, finally, sinter again to obtain the final alumina fiber ceramic matrix composite material;The composite material prepared by the application has good wave-transparent performance, strong mechanical properties, is suitable for use in extreme environments such as ultrahigh temperature and supersonic speed, and the prepared composite material has high surface flatness, is suitable for secondary processing, can be constructed in large size, and is environmentally friendly.

A device for preparing porous carbon spheres with uniform and controllable particle size is disclosed, which relates to the field of carbon material preparation technology. A stirring mechanism is disposed inside a mixing tank, and symmetrical conveying tanks are fixed to the top wall of the mixing tank. A proportioning conveying mechanism is disposed at the center of the outer top wall of the mixing tank and connected to the conveying tanks. A sealing block abuts against the inner top of the water outlet pipe at the bottom of the mixing tank, and a discharge pipe is movably disposed inside the water outlet pipe, which is connected to the sealing block via a linkage mechanism. An inlet on the upper side of the preparation chamber is inserted in conjunction with the discharge pipe. An isolation ring is disposed on the upper side inside the preparation chamber, and a sealing mechanism is disposed inside the isolation ring, which is connected to the inner bottom wall of the preparation chamber. Through the streamlined design of proportioning conveying, vacuum-assisted injection, and online template dissolution, a continuous process for preparing porous carbon spheres from raw material mixing to template removal is achieved, significantly improving the uniformity of product particle size, batch stability, and production efficiency.

The invention relates to the technical field of composite materials, and discloses a thin-layer composite material and a preparation process thereof, thin fiber dry yarn is laid on a bottom layer according to a preset direction, double faced adhesive tapes attached to two ends of the thin fiber dry yarn are temporarily fixed on the surface of the bottom layer, release paper is used for covering the exposed surface of the thin fiber dry yarn, and the thin-layer composite material is prepared. Pre-fixing of the thin fiber dry yarn is completed; vacuum auxiliary pressure is applied, the thin fiber dry yarn is preliminarily pressed into the bottom layer and fixedly embedded in the bottom layer, then the vacuum bag and the release paper are removed, and preliminary embedding of the thin fiber dry yarn is completed; fixing the two ends of the dry fiber yarn by using high-temperature-resistant adhesive tapes and removing the double-sided adhesive tapes to complete the fixation of the thin dry fiber yarn; the steps are repeated until the designed laying sequence and total thickness are achieved, and laying of the laminated laying layers is completed; and curing the laminated layer by adopting a composite material curing process, and immersing the resin in the fiber prepreg near the thin fiber dry yarn into the thin fiber dry yarn in the curing process to form a thin layer so as to prepare the thin-layer composite material.

This invention discloses a vacuum-assisted homogenization and temperature-controlled 3D printing method and apparatus for irregularly shaped viscoelastic propellants, belonging to the field of additive manufacturing technology for energetic materials. The vacuum-assisted homogenization and temperature-controlled 3D printing method for irregularly shaped viscoelastic propellants achieves online degassing and precise temperature control of the slurry in a closed vacuum environment through synergistic physical field control. The technical solution of this application has the following technical effects: it abandons the inert gas protection method that may introduce new gas sources, and adopts a synergistic physical degassing mechanism based on low vacuum negative pressure, supplemented by ultrasonic vibration and pulsed vacuum fluctuations. The stable negative pressure environment provides a continuous driving force for the escape of gas inside the slurry; ultrasonic vibration acts on the slurry, which can destroy the adhesion state of microbubbles and promote their aggregation; pulsed vacuum fluctuations cause the bubbles to be in a periodic expansion and contraction state, thereby accelerating their instability and rupture. The above three physical fields cooperate and work synergistically.

This invention relates to a natural fiber reinforced composite material sheet and its manufacturing method, applicable to the automotive, drone, architectural decoration, and consumer electronics industries. The sheet uses natural fiber fabrics such as flax, hemp, jute, sisal, or bamboo fiber as the reinforcing layer, which is cured with a resin matrix. The reinforcing layer can consist of 1 to 10 layers of natural fiber fabric, and plain weave, twill weave, satin weave, or multi-axial weave can be used as needed to obtain good tensile, bending, and interlayer bonding properties. This invention improves fiber impregnation uniformity and reduces moisture absorption through resin system modification, fiber surface treatment, and vacuum-assisted curing, overcoming the shortcomings of natural fiber composite materials in terms of interfacial bonding, dimensional stability, and process consistency. The resulting sheet is lightweight, has high damping, good electromagnetic wave transmission, and is environmentally friendly and low-carbon, and can be used in battery protection panels, drone arm tubes, sound insulation panels, and automotive interior cladding.

The utility model provides a large-displacement vacuum auxiliary self-priming pump which comprises a buffer box, the buffer box is connected with a vacuum unit and a drainage unit, the drainage unit comprises a water inlet pipe, the water inlet pipe is connected to a water inlet of the buffer box through a first flange, and a water outlet is formed in the side, corresponding to the water inlet, of the buffer box. An n-shaped bent pipe is arranged between the water inlet and the water outlet, one end of the bent pipe is connected with the water inlet, and the other end of the bent pipe is connected with the water outlet. The top of the bent pipe is communicated with a buffer tank, the water outlet is connected with the water inlet end of a centrifugal self-priming pump through a second flange, the water outlet end of the centrifugal self-priming pump is connected with a water storage tank through a third flange, and the top of the water storage tank is connected with a water outlet header pipe. The top of the buffer tank is connected with an exhaust pipe, and the exhaust pipe penetrates out of the top of the buffer tank and is connected with a vacuum unit through an exhaust branch pipe. When the large-displacement vacuum auxiliary self-sucking pump works, the vacuum unit and the drainage unit work cooperatively, so that the drainage efficiency of the drainage unit is improved.

The portable water harvesting device includes a vacuum-compatible water collection unit and a detachable lid incorporating a metal-organic framework (MOF) unit. The water collection unit comprises a vacuum pump connection port and a drain valve for extracting collected water. The detachable lid contains MOFs in the form of beads or dispersed within a porous medium, encapsulated by a vapor-permeable, MOF-retaining filter membrane. A solar-absorbing metal plate is affixed to the outer surface of the lid to facilitate thermal activation. The lid is removably attached to the collection unit via a screw-type or snap-fit closure, forming an airtight seal during vacuum desorption. Enhanced exposure of MOFs to ambient air improves water uptake, and vacuum-assisted depressurization accelerates desorption. The device is lightweight, power-independent, and suitable for deployment in off-grid or water-scarce environments such as islands, boats, or emergency lifeboats.

This invention discloses a self-heating curing process for carbon fiber composite materials, belonging to the field of composite material curing and molding technology. Addressing the problems of uneven temperature field, easy damage to carbon fibers, and high energy consumption in existing processes, this invention includes: plasma-activated carbon fiber fabric followed by layup; during layup, flexible conductive interconnect nodes are embedded along the length, width, and thickness directions inside the preform to construct a three-dimensional uniform conductive network through carbon fiber bundle overlap; resin impregnation is completed using vacuum-assisted resin transfer molding; heating and curing are achieved using a low-voltage DC power supply with the carbon fibers themselves as the internal heat source; and a four-stage stepped curing scheme is adopted, combining a closed-loop temperature control system: low-temperature pre-curing and bubble removal—medium-temperature uniform curing—high-temperature post-curing and stress relief—gradient cooling and demolding. The components of this invention exhibit a temperature difference ≤ ±1.5℃, a degree of curing ≥ 98.8%, and energy consumption reduced by more than 70%, making it suitable for different carbon fiber and resin systems, as well as large-size and irregularly shaped components.

Systems, devices, and methods comprising: a heat exchanger including: a shell including a first section and a second section, where one of the first section and the second section is one or more tubes disposed inside the shell, and the other is a void surrounding the one or more tubes inside the shell; the first section configured to receive hot fluid and recover heat from the hot fluid; the second section configured to receive cold fluid and generate steam using the recovered heat; a vacuum pump configured to lower a pressure of the second section inside the shell and receive the steam from the second section; and a vapor compressor configured to receive the steam from the vacuum pump and pressurize the steam.

This application provides an electromagnetic shielding nanofiber composite membrane and its preparation method, belonging to the field of electromagnetic shielding material preparation technology. The electromagnetic shielding nanofiber composite membrane provided in this application includes a three-dimensional framework substrate, and conductive and magnetic media uniformly dispersed in the three-dimensional framework substrate. The substrate and the conductive and magnetic media form a special three-dimensional network porous structure through overlap and adsorption. The composite membrane provided in this application has a thickness of 20-30 μm, an electromagnetic shielding effectiveness of 59 dB, and a maximum tensile stress of 12 MPa. The preparation method of this composite membrane is as follows: carboxylated carbon nanotubes, copper nanowires, and nickel ferrite are uniformly loaded into PVA-co-PE nanofibers through vacuum-assisted filtration, cross-linking, and hot pressing processes. The membrane can be formed in a single filtration step. The preparation method is simple and has good repeatability.

The application relates to the technical field of composite materials and discloses a single-thin-layer composite material and a preparation process, in which, on a bottom layer, single-thin-fiber dry yarns are laid in preset directions, temporarily fixed to the surface of the bottom layer by using double-sided adhesive tape attached to the two ends of the single-thin-fiber dry yarns, and the exposed surface of the single-thin-fiber dry yarns is covered with release paper to complete the pre-fixing of the single-thin-fiber dry yarns; vacuum-assisted pressure is applied to preliminarily press and embed the single-thin-fiber dry yarns in the bottom layer, then the vacuum bag and the release paper are removed to complete the preliminary embedding of the single-thin-fiber dry yarns; high-temperature-resistant adhesive tape is used to fix the two ends of the fiber dry yarns and remove the double-sided adhesive tape to complete the fixing of the single-thin-fiber dry yarns; the above steps are repeated until the designed layering sequence and total thickness are reached, and the laying of the laminated layers is completed; and the laminated layers are cured by using a composite material curing process, and the resin in the fiber prepreg near the single-thin-fiber dry yarns is immersed into the single-thin-fiber dry yarns to form a single-thin layer, so that the single-thin-layer composite material is prepared.

The application discloses a preparation method of an asymmetric layered PDMS electromagnetic shielding material, and specifically comprises the following steps f -Ni, AgNPs@GO powder, AgNPs@GO precursor, AgNWs, f -Ni@GO precursor; through f -Ni@GO precursor and AgNPs@GO precursor to obtain an asymmetric layered aerogel; in combination with AgNWs / PDMS conductive paste, an asymmetric three-layer structure is obtained; vacuum-assisted impregnation of PDMS and thermal curing are performed, and the asymmetric layered PDMS electromagnetic shielding material is obtained. The application further discloses the asymmetric layered PDMS electromagnetic shielding material, and solves the problem that polymer-based electromagnetic shielding composite materials in the prior art are difficult to simultaneously consider high electromagnetic shielding efficiency, low reflection characteristics and absorption-dominant shielding effect under the condition of low filler content.

The invention relates to the technical field of electric vehicle brake control, in particular to a pure electric light passenger car vacuum pump relay redundancy control and abnormity control method, which comprises the following steps of calling a brake signal and vehicle speed data to identify a brake requirement, calculating vacuum assistance and correcting a target quantity, collecting pressure and air pressure data to generate a vacuum fine adjustment amplitude, and performing vacuum fine adjustment on the vacuum fine adjustment amplitude. According to the method, by combining the linear correlation between the braking requirement level and the vacuum control reference interval, self-adaptive adjustment of the vacuum boosting requirement is achieved, starting and stopping control of the vacuum pump is optimized, and the control efficiency is improved. According to the method, the response capacity to external air pressure change and working abnormity is improved, system deviation is detected in real time and switching is carried out through relay redundancy control and an abnormity feedback mechanism, the reliability under high-load and complex working conditions is enhanced, the braking stability is enhanced, and the driving safety is improved.

The invention provides an intelligent adjusting method for the adsorption state of demolding cloth in vacuum-assisted forming, and relates to the technical field of demolding cloth adsorption state adjusting.The intelligent adjusting method comprises the steps that a to-be-adjusted mold surface 3D model is obtained, the first length is determined by presetting different grid side lengths, projecting the model to a grid and obtaining the curvature of cross points, and the complex evaluation index of the mold is calculated; a two-dimensional curved surface pressure distribution matrix is constructed by associating pressure values with grid positions; grid images in the adsorption process are collected to obtain a grid difference chart; the difference chart and the pressure matrix are input to a pressure vector calculation model; a grid node pressure vector is output; a negative pressure valve is used for primary node pressure regulation, a grid is used for secondary node detail regulation, a demolding cloth regulation model is constructed to cooperatively regulate the adsorption state, finally, the regulation state is judged according to a product quality evaluation index after demolding, and a pressure vector calculation model is fed back and optimized.

The invention discloses a construction technology of a bridge assembly type bracket bracket structure, relates to the technical field of bridge construction, and aims to solve the problems of waste of construction materials, poor precision, insufficient monitoring and the like of a traditional 0 # block bracket. The process comprises the following steps of: pre-embedding a detachable composite pre-embedded assembly comprising an inner pre-embedded steel box and an outer protective sleeve; installing a triangular bracket with an adjustable node connecting piece; intelligent equivalent pre-pressing is carried out through a reaction frame, and strain and displacement are monitored in real time; the pre-camber is set according to the elastic deformation, and an integrated folding formwork is installed; 0 # block concrete is poured in stages; intelligent tensioning and vacuum-assisted circulating grouting are carried out; and the inner pre-embedded steel box is synchronously dismantled and recycled in a grading mode. BIM is integrated in the whole process to realize visual management. According to the technology, cyclic utilization of the embedded parts is achieved, construction precision and efficiency are improved, safety is guaranteed, the green construction concept is met, and the technology is suitable for continuous beam bridge / continuous rigid frame bridge 0 # block construction.

The utility model relates to the technical field of battery production, and discloses a moisture evaporation device for battery production, which comprises an evaporation box, a vacuum mechanism, an evaporation mechanism, a placing rack and the like. A cover plate and a feeding port are arranged at the top of the evaporation box; the vacuum mechanism is composed of a suction pipe, a bent pipe, a vacuum pump, a dustproof sleeve and the like, vacuum can be formed in the box, the water boiling point is reduced, materials are prevented from being damaged, and evaporation efficiency is improved. A mounting plate, an evaporation sheet, a heat pipe and other structures of the evaporation mechanism can realize uniform and stable heating, and uniform heating of materials is ensured; and the placing rack facilitates placing and taking out of materials. Compared with the prior art, the moisture evaporation device for battery production has remarkable advantages in the aspects of vacuum assistance, uniform heating, convenient operation and the like, can effectively protect the performance of a battery material, improves the product quality, meets the strict requirements of modern battery production on a moisture evaporation link, and promotes the progress of a battery production technology.

The invention discloses a pyrolytic graphite and aluminum alloy high-strength metallurgical material containing a gradient transition layer and a preparation method of the pyrolytic graphite and aluminum alloy high-strength metallurgical material, and relates to the technical field of alloy materials. The method comprises the following steps: firstly, carrying out laser micro-texture treatment on the surface of a pyrolytic graphite core material to increase the bonding area; then preparing inner-layer powder and outer-layer powder of Cu-Ti-B4C components, sequentially depositing on the graphite surface through a cold spraying technology after ball milling, and constructing a gradient transition layer; then vacuum diffusion sintering is conducted, and metallurgical bonding of the transition layer and the graphite is achieved; then preparing an aluminum alloy melt containing graphene; and finally, preheating the graphite core material with the gradient layer, combining the aluminum melt with the transition layer by adopting a vacuum-assisted pressure casting process, and carrying out heat treatment to obtain a finished product. By constructing the gradient transition layer with gradually changed components and performance, interface thermal stress is effectively relieved, generation of harmful brittle phases is inhibited, and high-strength and high-thermal-conductivity reliable connection between pyrolytic graphite and aluminum alloy is achieved.

The invention discloses a carbon fiber soft felt impregnating and airing method, which comprises the following steps: pretreating a carbon fiber soft felt with a nitric acid solution with a specific concentration, preparing an impregnant containing epoxy resin, a curing agent and other components, and a microcapsule wall material is of a gelatin-polyurea multilayer structure and contains a repairing agent. Intermittent stirring and pressure and vacuum assistance are adopted during impregnation operation, so that sufficient permeation of the impregnant is ensured. And controlling the temperature, the humidity and the turn-over time during airing to cure the impregnant. The preparation of the microcapsule relates to the steps of inner layer gelatin coating, outer layer polyurea coating, urea-formaldehyde resin polymerization and the like, and gamma-aminopropyltriethoxysilane is added for treatment when the microcapsule is formed. The method can solve the problems of non-uniform impregnation, insufficient penetration depth, unstable microcapsule performance and the like in a traditional impregnation method, realizes uniform and sufficient penetration of the impregnant into the carbon fiber soft felt, and improves the performance and stability of the microcapsule, thereby improving the comprehensive performance of the carbon fiber soft felt composite material.

The invention discloses a preparation method and application of a multifunctional spongy N-doped MXene-coated AgMFs composite material, and belongs to the technical field of electromagnetic shielding materials. Two-dimensional transition metal carbide MXene and industrial-grade silver microchips AgMFs are driven by a solvent to complete interface self-assembly, a composite film is obtained in a vacuum-assisted filtering mode, and then the spongy N-doped MXene-coated AgMFs composite material is prepared through hydrazine hydrate treatment. The composite material prepared by the invention can ensure extremely high electromagnetic shielding effectiveness (79.1 dB, 8-12 GHz) of the material under the conditions of extremely thinness (86 microns) and extremely low density, and meanwhile, the shielding behavior is mainly dominated by absorption, so that the situation that electromagnetic pollution in a module is caused by over-strong reflection performance of most of current high-conductivity materials is avoided.