53 results about "Freeze-casting" patented technology

The invention relates to a bionic Al / SiC composite material with a three-dimensional network multilevel structure and a preparation method of the bionic Al / SiC composite material, and belongs to the technical field of new material preparation. According to the method, through the collaborative process of freeze casting and organic foam impregnation, the problem that in the prior art, the multilevel aperture and the complex network structure are difficult to cooperatively regulate and control is solved. The preparation method comprises the following specific steps: preparing tert-butyl alcohol-based ceramic slurry, impregnating the slurry with polyurethane foam, performing freeze casting molding, removing a solvent through freeze drying, performing high-temperature sintering to form SiC ceramic with a three-dimensional reticular hierarchical pore structure, and finally preparing the Al / SiC composite material through a vacuum pressure infiltration process. Wherein a sintering aid is added into the slurry, so that the sintering temperature is obviously reduced; the specification (40-60 ppi) of polyurethane foam, the solid phase content (20-30 vol.%) of slurry, the freezing speed (0-90 DEG C) and the content (5-20 wt.%) of a sintering aid are regulated and controlled. And the cross-scale collaborative design of micron-scale directional holes and millimeter-scale mesh holes is realized. The Al / SiC composite material prepared by the invention has the advantages that the compressive strength, fracture toughness and other properties are obviously higher than those of the traditional single-aperture porous ceramic, and the Al / SiC composite material is suitable for the fields of manufacturing and energy absorption of precise instruments, electronic packaging and optical devices.

The invention relates to the technical field of inorganic material preparation and new energy materials, and particularly discloses a lithium metal battery composite solid electrolyte as well as a preparation method and application thereof. Lithium niobate with high lithium ion conductivity and high dielectric constant is used as an inorganic filler, polyvinylidene fluoride-co-hexafluoropropylene is used as a polymer matrix, and the lithium metal battery composite solid electrolyte is prepared. The lithium metal battery solid electrolyte with a continuous lithium ion transport path is constructed through a freeze casting technology, the dielectric constant of the solid electrolyte is effectively improved by adding the dielectric inorganic filler lithium niobate, lithium salt dissociation is promoted, preparation of the modified electrolyte can be simply completed on a large scale, industrial expansion is facilitated, coulombic efficiency is improved, and the lithium metal battery solid electrolyte is suitable for industrial production. According to the present invention, the lithium metal battery electrolyte meets the industrial requirement on the high lithium utilization rate, the lithium negative electrode can be well protected, the cycle life of the lithium electrode can be improved, the battery electrolyte and the lithium electrode show the good interface compatibility and the good cycle stability, and the new feasible way is provided for the application of the lithium metal battery.

The invention provides a fabric-reinforced electroactive nerve conduit and a preparation method and application thereof, and belongs to the field of biomedical materials.The fabric-reinforced electroactive nerve conduit comprises a nerve conduit inner layer and a nerve conduit outer layer, the nerve conduit inner layer is a woven skeleton formed by magnesium wires serving as parallel yarns and degummed silk through a three-dimensional weaving process, the pore diameter of the nerve conduit inner layer is 1.5-2 mm, and the thickness of the nerve conduit inner layer is 0.5-1 mm; the outer layer of the nerve conduit is a composite layer with a radial finger-shaped porous structure, which is formed by directionally freezing and casting a hydrogel cross-linked network formed by mixing potassium sodium niobate nanorods modified by polydopamine and a biopolymer material, and the thickness of the outer layer of the nerve conduit is 1-2mm. A three-dimensional weaving technology, a piezoelectric nano material and a biopolymer material are combined, a novel multifunctional nerve conduit is developed to repair nerve injury, a better solution is provided for nerve repair, and the fabric enhanced electric activity nerve conduit has important practical guiding significance in application of future clinical nerve injury repair.

The invention relates to a low-heat-conduction high-strength phase change energy storage wallboard and a preparation method and application thereof.The phase change energy storage wallboard comprises a wallboard base material D and a phase change material, the wallboard base material D is a cement-based material with a directional communication pore channel structure, and the phase change material is loaded in the directional communication pore channel structure. The preparation method comprises the following steps: preparing a wallboard base material D with a directional communicated pore channel structure through a freeze casting method; loading the phase change material into the wallboard base material D through a vacuum impregnation method to obtain a wallboard base material E; the wallboard base material E is put into a temperature control curing room to be cured for 1-2 days, and the low-heat-conduction and high-strength phase change energy storage wallboard is prepared. Compared with the prior art, the contradictory requirement between the heat conductivity and the strength of the wallboard is met, the vertical bearing capacity of the wallboard is greatly improved, and the heat conductivity coefficient of the wallboard is remarkably reduced. The phase change energy storage wallboard has extremely high mechanical properties and flexible and efficient temperature regulation and control effects.

The invention belongs to the technical field of desulfurization gas purification, and particularly relates to a desulfurizing agent and a preparation method thereof. The desulfurizing agent is an iron-zinc-calcium composite oxide material with a hierarchical porous structure, and the preparation method of the desulfurizing agent comprises the following steps: performing amination modification on xanthan gum, then mixing the modified xanthan gum with nano cellulose, and then preparing slurry with a metal salt solution containing Fe, Zn and Ca; performing two-way temperature gradient freezing casting and freeze drying to obtain a precursor; and finally, roasting and activating under programmed temperature control. According to the preparation method, nano-scale dispersion of active components is realized by virtue of strong coordination of aminated xanthan gum and metal ions, and a high-strength and through hierarchical pore framework is constructed by virtue of nanocellulose enhancement and freezing casting. The obtained desulfurizer has ultrahigh one-time sulfur capacity, high mechanical strength and excellent structural stability, is complete in form after being used, is convenient for resource recovery, and is suitable for efficient removal of hydrogen sulfide in industrial gases such as refinery gas.

The invention relates to a high-strength energy storage floor tile and a preparation method and application thereof.The floor tile comprises an energy storage sandwich and a high-strength shell wrapping the energy storage sandwich, the energy storage sandwich comprises a cement-based electrolyte, a positive electrode and a negative electrode, the positive electrode and the negative electrode are assembled on the two opposite sides of the cement-based electrolyte, and the high-strength shell is an ultra-high-performance concrete-based shell; the preparation method comprises the following specific steps: constructing a porous cement-based electrolyte by adopting a freeze casting technology; assembling a mesh electrode, and adopting vanadium oxide as a positive electrode and a zinc sheet as a negative electrode; the high-strength energy-storage floor tile is obtained after packaging is conducted through an ultra-high-performance concrete-based shell. Compared with the prior art, freezing casting and floor tile structural design are combined, the energy storage floor tile has high strength and matched energy storage performance at the same time, the energy storage floor tile is suitable for the field of building decoration, integration of decoration, energy storage and structural performance is achieved, and the functionalization level and low-carbon development of traditional building materials are greatly improved.

The invention discloses a method for preparing a shaped pearl oyster-like structure ceramic-paraffin composite phase change energy storage material, which relates to the field of new material preparation, in order to overcome the problems of low thermal conductivity of phase change energy storage materials during phase change, easy leakage of phase change materials, complex preparation process and low efficiency. The raw materials of the shaped pearl oyster-like structure ceramic-paraffin composite phase change energy storage material are composed of Al2O3, Fe3O4 ceramic powder and industrial paraffin. The present invention adopts magnetic field freezing casting to prepare pearl oyster-like "brick-mud" Al2O3 porous ceramics, and obtains composite phase change energy storage materials after pressureless infiltration of paraffin in porous ceramics. The composite material has high energy storage density, high thermal conductivity, and controllable microstructure. After the paraffin is melted, it does not leak in the ceramic carrier, has high energy storage efficiency, and is environmentally friendly. By imitating the highly ordered "brick-mud" microstructure of pearl oysters to construct a continuous and orderly heat transfer path, the ceramic skeleton can achieve high thermal conductivity and anisotropy.

The application discloses a kind of 3D printing auxiliary freeze casting preparation wide frequency high-strength sound-absorbing material method, product and application, belong to sound-absorbing material technical field, including the following steps: using 3D printing process, polymer I and polymer II are prepared to obtain Helmholtz resonator, and slurry is dispersed in Helmholtz resonator by freeze casting process to realize dispersion orientation, and wide frequency high-strength sound-absorbing material is prepared.The application utilizes 3D printing to manufacture specific structure shape on demand, to a certain extent, the sound-absorbing performance and mechanical properties of sound-absorbing material are realized;Combined with the directional orientation of freeze casting technology, effective sound absorption in wide frequency range is realized, and the sound-absorbing performance of sound-absorbing material is greatly improved.

The invention discloses a preparation method of anisotropic glass fiber aerogel. The preparation method comprises the following steps: preparing a glass fiber dispersion liquid; preparing an aluminum dihydrogen phosphate solution; preparing a polyvinyl alcohol solution; uniformly mixing the three solutions, pouring the mixed solution into a customized mold, freezing until the mixed solution is completely solidified, and then freeze-drying to obtain the glass fiber aerogel. The aerogel is influenced by a plurality of temperature gradients, ice crystals vertically grow along the temperature gradients to form sheet layers, different cold surfaces interact to cause the ice crystals to grow along a plane from the radial direction to the center of the square mold, and finally an array radiation structure composed of four cones is formed. The glass fiber aerogel prepared through the synergistic cooperation of a freezing casting technology and aluminum dihydrogen phosphate has anisotropy and highly-ordered lamellae, so that the glass fiber aerogel shows good low heat-conducting property.

The application discloses a preparation method of anisotropic glass fiber aerogel, which comprises the following steps: preparing a glass fiber dispersion solution; preparing an aluminum dihydrogen phosphate solution; preparing a polyvinyl alcohol solution; uniformly mixing the three solutions, pouring into a customized mold, freezing until complete solidification, and then performing freeze drying to obtain the glass fiber aerogel. Due to the influence of multiple temperature gradients on the aerogel, ice crystals grow vertically along the temperature gradient to form lamellas, and different cold surfaces interact to cause them to grow along the radial plane to the center of the square mold, finally forming an array radiation structure composed of four cones. The glass fiber aerogel prepared through the synergistic cooperation of the freeze casting technology and the aluminum dihydrogen phosphate has anisotropy and highly ordered lamellas, and therefore exhibits good low thermal conductivity.

The invention discloses an ultrathin flexible ceramic plate as well as a preparation method and application thereof. The ultrathin flexible ceramic plate is prepared from the following raw materials: cordierite powder, PAN (Polyacrylonitrile) fiber, polysiloxane, nano Al2O3, aluminum dihydrogen phosphate sol and a fluorocarbon resin composite coating. The preparation method comprises the following steps: 1) pretreatment; 2) freezing and casting; 3) heat treatment and carbonization; 4) fluorocarbon coating process and hot isostatic pressing; the preparation method comprises the following steps: firstly, carrying out freeze casting to obtain a ceramic plate matrix, and carrying out hot pressed sintering on the ceramic plate matrix to carbonize PAN fibers into carbon fibers to obtain high-strength single-layer ceramic sheets and composite ceramic sheets, so as to obtain the flexible ceramic plate. The obtained ultra-thin flexible ceramic plate is high in strength and toughness, resistant to high temperature and good in sound insulation and heat insulation effect, through precise configuration and chemical coupling of the components, the problem that a ceramic material is crisp if being strong and weak if being thin is solved, and a new scheme is provided for industrialization of flexible ceramics.

The invention discloses a preparation method of porous ceramic with a non-uniform fusion structure, which comprises the following steps: step 1, constructing a fusion function, and determining parameters of the fusion function; 2, preparing a wax pattern negative template; step 3, preparing ceramic slurry; step 4, dipping and freezing; step 5, low-pressure drying; and 6, sintering to obtain the TPMS structure porous ceramic. The invention further discloses the porous ceramic with the non-uniform fusion structure. The invention further discloses application of the porous ceramic with the non-uniform fusion structure in the field of bionic bone scaffolds. According to the method, the fusion function is constructed by fusing the G-shaped function and the TPMS function, so that non-uniform fusion of various hole patterns is realized; the mode of wax negative template freezing casting and indirect forming is adopted, the design freedom degree of a complex structure is reserved, meanwhile, the problems of resolution limitation, shrinkage deformation, supporting difficulty and the like during direct 3D printing of the porous ceramic are solved, and the use effect is good.

The invention relates to a cement-based zinc battery with low interface impedance and a preparation method and application thereof. The cement-based zinc battery comprises a cement-based electrolyte, and a positive electrode material layer and a negative electrode material layer which are respectively melted and fixed on two opposite sides of the surface of the cement-based electrolyte through a 3D printing technology. The method comprises the following specific steps: manufacturing a porous cement-based structure through a freeze casting technology, and soaking the porous cement-based structure in a salt solution for use; a cement-based electrolyte and a zinc (copper) electrode are assembled in an environment filled with inert gas through a fixed laser scanner and 3D printing equipment, copper serves as a positive electrode, the cement-based electrolyte serves as the electrolyte, and zinc serves as a negative electrode. Compared with the prior art, the electrode material is directly melted and fixed on the surface of the cement-based electrolyte, so that the interface stability of the electrode and the electrolyte is improved, the problem of high interface impedance of the electrolyte and the electrode is solved, the overall performance of the battery is improved, and the process is simple.

The present invention relates to the technical field of phase change composite materials, and specifically to a high-strength and high-thermal-conductivity composite phase change fiber, a preparation method, and an application thereof. Using carbon nanotube fibers as a substrate, hydrothermal method and freeze casting technology are adopted to rapidly solidify water molecules distributed in the pores of the carbon nanotube fibers or between the carbon nanotubes to form an ordered ice crystal structure, thereby forming a multi-layer ordered pore structure in the carbon nanotube fibers. The carbon nanotube fibers with a porous ordered structure are then immersed in a phase change material solution. Under evaporation concentration and capillary action, the phase change material fully penetrates into the multi-layer ordered pore structure of the carbon nanotube fibers, and is washed in a hot water bath to obtain a composite phase change fiber having high tensile strength, high thermal conductivity, low density, a wide adjustable range of phase change temperature, and high phase change enthalpy or latent heat. It has very broad application prospects in the fields of thermal interface materials, energy storage materials, and high-temperature protective materials.

The application discloses a preparation method of non-uniform fusion structure porous ceramic, comprising the following steps: step one, constructing a fusion function and determining parameters of the fusion function; step two, preparing a wax negative template; step three, configuring ceramic slurry; step four, impregnating and freezing; step five, low-pressure drying; and step six, sintering, so as to obtain TPMS structure porous ceramic. The application also comprises non-uniform fusion structure porous ceramic. The application also comprises application of the non-uniform fusion structure porous ceramic in the field of biomimetic bone scaffolds. The application constructs a fusion function by fusing a G-shaped function and a TPMS function, realizes non-uniform fusion of various pore types, adopts a wax negative template freezing casting and an indirect forming mode, retains the design freedom of a complex structure, solves problems such as resolution limitation, shrinkage deformation and support difficulty that are faced by direct 3D printing of porous ceramic, and has good use effect.

This invention discloses an intelligent handling device for frozen sand molds with environmental sensing capabilities, suitable for frozen casting production lines. The device includes a walking mechanism, a support and lifting mechanism, a sand mold clamping and tilting mechanism, an environmental sensing module, and a central control module. The walking mechanism is the power source for the entire machine's movement and consists of a frame chassis, drive wheels, and casters. The support and lifting mechanism consists of an electric cylinder, a pressure sensor, and a crossbeam. The sand mold clamping and tilting mechanism consists of a linear module, clamping arms, clamping plates, a load-bearing shaft, a copper sleeve, a mounting bracket, strain gauges, a hollow rotating platform, and a drive motor. The environmental sensing module is mounted on the frame of the handling device. The block consists of a 3D dot matrix scanning sensor, a machine vision camera, and a thermal imager. The central control module collects data from pressure sensors, strain gauges, and environmental sensing modules in real time for analysis and decision-making. It generates the current optimal working parameters and adjustment parameters through methods such as coupling mapping and digital twins, and feeds them back to each mechanism for real-time control to optimize the handling process. This invention solves the problem of large-scale frozen sand handling and turning in the molding process in a cryogenic casting production line, improves the molding efficiency and accuracy of sand molds, greatly reduces manpower, and plays a role in cost reduction and efficiency improvement for the entire cryogenic casting production line, which is in line with the national trend of developing green casting.

The invention discloses a porous mullite ceramic with a fiber structure and a preparation method thereof, and belongs to the field of preparation of porous ceramic materials. Research finds that aluminum-doped modified silica sol and AlF3 have a synergistic effect in the aspect of improving the mechanical property of the mullite porous ceramic, and the aluminum-doped modified silica sol is fused and enriched at a precursor contact point during sintering to form liquid-phase bridging; alF3 is decomposed at a high temperature to generate gaseous fluoride, so that anisotropic growth of mullite whiskers is promoted, and a three-dimensional interlocking network is formed. The mullite precursor can optimize the pore structure distribution, the porous mullite preparation method provided by the invention solves the problem that the pore structure is difficult to regulate and control flexibly in the traditional freezing casting process, the mechanical property of the porous ceramic is greatly improved, and the high porosity and the structural strength are superior to those of the porous ceramic prepared by freezing casting in the prior art.

The invention belongs to the technical field of solid oxide electrolytic cell (SOEC) anode preparation, and relates to an SOEC anode microchannel preparation method adopting a freeze casting process and an anode structure. The preparation method comprises the following steps: S1, preparing slurry: adding YSZ powder, a latex emulsion binder, a magnesium aluminum silicate thickener and an ammonium polyacrylate dispersant into deionized water according to a mass ratio of 8: 1.5: 0.5: 0.3, and stirring to form uniform slurry with the solid content of 40-50%; the vertical micro-channel stent is realized through a directional freezing casting process, so that the oxygen transmission efficiency is remarkably improved; the low-temperature constant-temperature stirring reaction bath adopts a dry ice solvent bath method, the preparation and maintenance of the method are simple and easy to operate, the temperature reproducibility of the dry ice solvent bath is better, and the change of the steady-state temperature can be controlled within the range of + / -1 DEG C.

The invention relates to a preparation method of a pectin-based anionic adsorbent, and belongs to the field of adsorbent preparation. According to the preparation method, pectin is taken as a matrix, N, N '-methylenebisacrylamide is taken as a cross-linking agent, and the pectin-based cryogel particle medium is successfully prepared by adopting a freezing casting method and an airflow cutting drop-making technology. Then, the prepared pectin-based cryogel medium reacts with an ammonia water solution for amidation and then reacts with maleic anhydride, and finally the pectin-based anionic adsorbent is obtained. The pectin-based anionic adsorbent prepared by the preparation method disclosed by the invention takes polysaccharide as a matrix, has biodegradability, is environment-friendly, has relatively large adsorption capacity and relatively high adsorption rate, and shows a wide application prospect.

The invention discloses bionic Al2O3 porous ceramic with a bidirectional gradient structure and a preparation method of the bionic Al2O3 porous ceramic, and belongs to the field of ceramic material preparation. Aiming at the problem that a multi-directional gradient structure is difficult to construct by a traditional freezing casting technology, bidirectional gradient regulation and control of a pore structure and components along a freezing direction and a magnetic field direction are realized through a synergistic effect of magnetic field assisted freezing casting and a non-aqueous solvent system. The porous ceramic takes Al2O3 as a matrix, is doped with 3wt.%-9wt.% of Ni powder as a magnetic additive, and takes tert-butyl alcohol (TBA) as a solvent to form bidirectional gradient distribution: the pore diameter and the wall thickness in the freezing direction change in a gradient manner; gradient distribution of a Ni enrichment area (pore orientation parallel magnetic field) and a Ni depletion area (pore orientation parallel freezing direction) is formed in the magnetic field direction. The preparation method comprises the steps of slurry preparation, magnetic field-assisted directional solidification, freeze drying and high-temperature sintering. The method is simple and controllable in process, and is suitable for the fields of biomedical bone repair, environmental filtration, battery energy and the like.

The application is a kind of precise forming method for printing magnesium alloy castings by gradient mixing of flame retardant in freeze casting. First, the components of the flame retardant are proportioned, then the shape and layer thickness of the high flame retardant and low flame retardant sand layer in the gradient sand mold are designed according to the structure characteristics of the typical magnesium alloy castings to be poured, and at the same time, the protection gas pipeline is designed in the low flame retardant sand layer combined with the structure of the castings. Subsequently, the control system sprays water binder onto the laid sand powder bed, layer by layer, to complete the preparation of the gradient sand mold. The printed gradient sand mold is frozen, and before pouring, SF6+CO2 protection gas is introduced through the reserved vent pipe, and after a period of aeration, low-temperature pouring is carried out to obtain magnesium alloy castings. The application can reduce the use of flame retardant, prevent explosion reaction with water vapor, reduce production cost, make the freeze casting technology play a role in the production of complex magnesium alloy castings, and meet the development requirements of green casting.

The invention relates to the technical field of preparation and processing of new materials, and discloses a freeze casting-chemical crosslinking synergistic preparation method of a carbon nanotube-nanocellulose aerogel composite material. According to the method, a layered pore structure is directionally constructed through freeze casting and mutually supports a covalent network formed through chemical crosslinking; the mechanical strength, the compression resilience and the structural stability of the aerogel composite material are greatly improved; by pretreating the raw materials and combining with a surfactant dispersion process, uniform dispersion and interface chemical bonding of the carbon nanotubes and the nanocellulose are realized, so that phase separation is effectively inhibited, and the electric conductivity / heat conductivity is enhanced; through programmed freezing and drying processes in the preparation process, the morphology and distribution of pores are accurately controlled, so that the aerogel composite material can be endowed with anisotropic functional characteristics while the ultralow density is maintained; the method solves the problems that a traditional aerogel material is loose in structure, weak in interface bonding, single in function and uncontrollable in microstructure.

The invention relates to a method for producing cast ingots (1), in particular from steel, wherein liquid metal is dispensed either directly from a ladle (11) or via an intermediate vessel (12) into a downwardly open mold (15) or a crucible, wherein, when using a downwardly open mold (15), the at least partially solidified cast ingot (1) is withdrawn from the mold (15) in the direction of the longitudinal axis (5) by means of a tapping die (28) which is movable in height in the direction of a longitudinal axis (5) of the cast ingot (1) and on which the cast ingot (1) is at least indirectly arranged.

The invention discloses a polytetrafluoroethylene / polyphenylene sulfide composite coating with a micro-nano pore structure and a preparation method of the polytetrafluoroethylene / polyphenylene sulfide composite coating. The method comprises the following steps: dispersing PTFE powder in an ethanol / water / surfactant mixed solvent, and dispersing PPS resin powder in ethanol to respectively prepare dispersion liquids; mixing in proportion and spraying on a metal substrate to form a wet film; freezing the wet film at the temperature of 0 DEG C to-30 DEG C for hole casting; heating and curing at 100-200 DEG C and 370-390 DEG C to promote sublimation of ice crystals and emulsification and expansion of the surfactant to synergistically expand pores; and finally, cooling and crystallizing to obtain the coating with the micro-nano composite pore structure. The method is simple in process, green, environmentally friendly and controllable in pore structure, and the optimal pore structure (the micron pore diameter is about 51.49 microns, and the nano pore diameter is about 215 nm) can be obtained at the temperature of-10 DEG C. The coating is stable in structure, the dry friction coefficient is 0.155, good mechanical durability is shown, and the specific micro-nano porous structure of the coating has wide application prospects in the fields of icing prevention, oil-water separation, oil storage and lubrication and the like.

The invention provides an ultrahigh-rigidity magnesium-based composite material as well as a preparation method and application thereof. The preparation method comprises the following steps: preparing aluminum oxide ceramic slurry into a ceramic preform by adopting a freezing casting method; and a vacuum pressure infiltration method is adopted for infiltrating magnesium alloy into the ceramic prefabricated body, and the ultrahigh-rigidity magnesium-based composite material is prepared. According to the ultrahigh-rigidity magnesium-based composite material and the preparation method and application thereof, the same mechanical property as that of a traditional aluminum alloy component is guaranteed, and meanwhile the ultrahigh-rigidity magnesium-based composite material is lighter.

The invention discloses a preparation method of a graphite-copper uniform layered composite material. The preparation method comprises the following steps: plating a metal coating on the surface of a graphite flake; preparing slurry from the product, a freezing medium and a binder; solidifying the obtained slurry at a fixed liquid-solid interface solidification speed by using a freezing casting method; freeze-drying the solidified slurry to obtain a layered porous graphite skeleton green body; and degreasing and sintering the layered graphite skeleton green body, and infiltrating copper to obtain the graphite-copper uniform layered composite material. The invention further discloses a graphite / copper uniform layered composite material, the volume fraction of copper in the composite material is 30%-70%, the thermal conductivity is 400-650 W / (m.K), and the thermal expansion coefficient is (0-3) * 10 <-6 > / K. According to the graphite-copper uniform layered composite material prepared by adopting the ice template-infiltration method, the orientation height of a graphite sheet layer is consistent, and the graphite-copper uniform layered composite material has a low and adjustable thermal expansion coefficient and a high heat conductivity coefficient.

The invention relates to the technical field of nano composite materials, in particular to silk fibroin-based iron tannate coating composite aerogel as well as a preparation method and application thereof. Pouring the silk fibroin solution into a polystyrene mold, performing freeze drying by adopting a freeze casting method to obtain silk fibroin-based aerogel with a single orientation structure, soaking the silk fibroin-based aerogel in a mixed solution of a tannic acid-Tris solution and an APTES solution, adsorbing tannic acid molecules, and drying to obtain the silk fibroin-based aerogel with the single orientation structure. The preparation method comprises the following steps: alternately washing redundant tannic acid on the surface with deionized water and ethanol, soaking the aerogel in a ferric sulfate solution to form a tannic acid-iron ion complex on the surface of the aerogel, washing redundant iron ions with deionized water, and freeze-drying to obtain the silk fibroin-based tannic acid iron coating composite aerogel. The silk fibroin-based iron tannate coating composite aerogel solves the problem that the silk fibroin-based three-dimensional porous material is easily subjected to biofouling and damage to cause performance loss, and the silk fibroin-based iron tannate coating composite aerogel has better light absorption and photo-thermal performance than silk fibroin-based aerogel.

The invention discloses heterogeneous aerogel based on waste paperboards as well as a preparation method and application of the heterogeneous aerogel. The heterogeneous aerogel based on the waste paperboard is composed of aerogel and a phase change material, and the aerogel is prepared by crushing and soaking the waste paperboard and then using a freezing casting method; the phase change material is an organic phase change material. Only water is used as a solvent, so that the preparation process is more environment-friendly. Compared with aerogel prepared from cellulose, the cost is lower. The aerogel and the phase change material have good energy absorption characteristics after being compounded, so that the aerogel composite material has buffering characteristics. Meanwhile, when the heterogeneous aerogel is prepared, a heterogeneous structure with any layer number can be formed through a staged laminated freezing technology, and the multifunctional heterogeneous aerogel composite material with multiple functions of photo-thermal, electric heating, catalysis, adsorption and the like is formed according to different additives in each layer of aerogel.

The invention discloses a Ca3Co4O9 thermoelectric fiber ceramic aerogel material with an infrared stealth characteristic and a preparation method of the Ca3Co4O9 thermoelectric fiber ceramic aerogel material, and belongs to the field of thermoelectric materials. A directional freezing pouring technology is adopted, a loose skeleton is constructed through Ca3Co4O9 nanofiber self-assembly, micron-sized through holes arranged in parallel are formed through directional freezing induction, a nano-sized secondary pore network is formed under ice crystal growth pushing, and finally the ultra-light, high-porosity and uniform-structure thermoelectric fiber ceramic aerogel material is prepared. The material has excellent thermoelectric performance, and the oriented through hole structure of the material increases phonon scattering and inhibits gas heat transfer by prolonging a solid heat conduction path in the direction perpendicular to a pore channel, so that the heat conductivity is remarkably reduced, and efficient heat insulation is achieved; and the thermal infrared stealth performance is greatly improved while the thermoelectric conversion capability is maintained. The method is simple in process, low in raw material cost and controllable in process, and the obtained material is pure in component and stable in performance and has important application value.

The invention relates to the technical field of thermal interface materials, and discloses an elastic thermal interface material suitable for electronic packaging and a preparation method thereof. Comprising the following operation steps: step 1, uniformly dispersing heat-conducting insulating powder in a solvent to obtain a heat-conducting insulating powder dispersion liquid; carrying out freeze casting and freeze drying to obtain a heat-conducting aerogel skeleton; step 2, slowly dropwise adding a polydimethylsiloxane solution into a container filled with the heat-conducting aerogel skeleton along the wall, standing at room temperature after reaching a saturated state, and curing under a high-temperature condition to obtain an elastic thermal interface material; the heat-conducting insulating powder is boron nitride; the solid content of the heat-conducting insulating powder dispersion liquid is 5-20wt%. The elastic thermal interface material prepared in the scheme has good thermal conductivity and mechanical properties.