23 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 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 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 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 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 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 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 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.

Frozen, porous thin films and methods of making and use thereof are described herein. The frozen, porous thin films can comprise a continuous phase permeated by a plurality of pores; wherein the continuous phase comprises a polymer, a ceramic material, or a combination thereof. In some examples, the frozen, porous thin films are made by freeze casting.

A method 100 of manufacturing a refractory 204 for continuous casting, the method comprising; forming, via freeze casting, a precursor structure 201 of the refractory 204; impregnating the precursor 2

A method for preparing an aluminum-based composite material in which silicon carbide nanocrystals and micron-sized particles are layered is disclosed. This invention addresses the problems of uncontrollable reinforcement distribution, difficulty in oriented whisker alignment, and difficulty in achieving dense impregnation of preforms under high ceramic content conditions in existing aluminum-based composite materials. The steps of this invention include: Step 1, acid washing of the whiskers and particles; Step 2, preparation of a slurry; Step 3, freeze casting to form a preform; Step 4, vacuum freeze drying; Step 5, sintering of the preform; and Step 6, extrusion impregnation of the aluminum-based composite material. This invention belongs to the field of aluminum-based composite material preparation technology.

The invention discloses a hierarchical anisotropic self-repairing conductive hydrogel electrode material, a preparation method and application, and belongs to the technical field of electrode materials. The hydrogel takes a polyacrylamide-polyacrylic acid-polyaniline copolymerization network formed by polymerization as a core skeleton, contains a covalent-dynamic non-covalent double cross-linked network, is doped with carbon nanotubes, constructs a synergistic conductive system by combining polyaniline in the copolymerization network, and is prepared by directional freeze casting, low-temperature polymerization and KCl ion strengthening treatment. The hierarchical anisotropic microstructure is composed of micron channels parallel to the freezing direction and interconnected nano porous structures uniformly distributed in the walls of the channels and in a polymer network. By means of the structural design and the synergistic conductive system, collaborative optimization and improvement of mechanical, conductive, adhesion, biocompatibility and self-repairing multi-dimensional performance are achieved through the synergistic effect of ion strengthening, the process is simple and repeatable, the application requirements in the fields of flexible wearable bioelectric electrodes and the like are perfectly met, and the application prospect is wide.

The application 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 coated outside, the energy storage sandwich comprises a cement-based electrolyte and positive and negative electrodes assembled on opposite sides of the cement-based electrolyte, and the high-strength shell is an ultra-high performance concrete-based shell. The specific steps of the preparation method are as follows: a porous cement-based electrolyte is constructed by adopting a freeze casting technology; a reticular electrode assembly is carried out, vanadium oxide is used as the positive electrode, and zinc sheet is used as the negative electrode; and the high-strength energy storage floor tile is obtained after being packaged by adopting the ultra-high performance concrete-based shell. Compared with the prior art, the application is combined with the freeze casting and the floor tile structure design, has high strength and also has matched energy storage performance, the energy storage floor tile is suitable for the field of building decoration, realizes the integration of decoration, energy storage and structural performance, and greatly improves the functionalization level of traditional building materials and low-carbon development.

The invention relates to a preparation method and device of a cross-scale porous material, based on freeze casting and surface acoustic wave cooperative regulation and control, through dynamic multi-scale regulation and control, real-time matching of process parameters, and directional construction and morphology optimization of macroscopic to microscopic multistage pores, precise construction of the multistage pores and improvement of structural stability are achieved, and the preparation method and device of the cross-scale porous material are suitable for industrial production. The material is suitable for high-performance scenes such as fuel cell electrodes and artificial bones.

The application belongs to the field of sound absorption and noise reduction materials, and discloses a porous ceramic / piezoelectric polymer aerogel composite material for sound absorption and noise reduction and a preparation method thereof.The preparation method is as follows: (1) preparing ceramic slurry; (2) taking porous polymer as a precursor template, mounting the ceramic slurry, and drying to obtain a green body; (3) heating and sintering to obtain a porous ceramic matrix; (4) preparing a homogeneous solution of piezoelectric polymer material; (5) pouring the solution into the porous ceramic matrix and freeze casting; (6) freeze drying and quenching to obtain the porous ceramic / piezoelectric polymer aerogel composite material.The microstructure of the composite material is improved, the piezoelectric polymer aerogel component with secondary pore structure is introduced into the first-stage pore structure, and an additional sound-electricity conversion energy loss mechanism is introduced, so that the composite material obtained by the application has excellent absorption effect on noise in a wide frequency range of 250 Hz to 6400 Hz.

The present application relates to a boron nitride aerogel / phase change heat conduction composite material and a preparation method thereof. The preparation method of the boron nitride aerogel / phase change heat conduction composite material comprises the following steps: (1) pouring a graphene oxide dispersion liquid into a mold and placing it in a low-temperature environment for freeze casting, then freeze-drying and heat-treating the freeze-cast sample to obtain a three-dimensional centripetal structure graphene aerogel; (2) using the three-dimensional centripetal structure graphene aerogel as a template, depositing boron nitride on the surface of graphene through in-situ reaction by using a chemical vapor deposition process to obtain a graphene / boron nitride hybrid aerogel; (3) performing heat etching and high-temperature oxidation treatment on the graphene / boron nitride hybrid aerogel to remove the graphene component to obtain a radiating structure boron nitride aerogel; and (4) immersing a phase change material into the radiating structure boron nitride aerogel by using a vacuum-assisted impregnation method under heating conditions, and obtaining the boron nitride aerogel / phase change heat conduction composite material after solidification.

A metal foam structure is used for numerous energy applications such as battery, electrolyzer, fuel cell, carbon capture, thermal management, and others due to its enhanced surface area to be utilized for improved efficiency. A net-shape metal foam sheet or plate production with desired thicknesses without cutting process is thus required to significantly reduce the manufacturing cost and to be more price competitive against other types of existing similar materials such as carbon paper, metal foil, mesh, plate, and others. In order to achieve this, a vertical freeze casting is described where the freeze casting of the metal slurry takes place with the metal slurry plate mold being placed vertically with respect to the ground, whereas the conventional freeze casting process takes place with the metal slurry plate mold being placed horizontally with respect to the ground.

A metal foam ball, several millimeters in diameter, is manufactured to have an open-pore structure to absorb fluid (e.g., gas and liquid) such as water or lubricant. As an example, a copper foam ball is manufactured via a freeze casting method using prepared oxide powder slurry where a spherical silica gel mold is used to freeze the slurry, which is subsequently dried at low temperature in vacuum and then sintered at high temperature. For improved oxidation, copper alloy foam ball or copper foam ball coated with tin can also be manufactured through the same method. For improved strength, steel, copper-nickel alloy, or titanium foam ball can also be manufactured through the same method.

Certain examples of the present disclosure relate to methods and systems for manufacturing refractories. Certain examples provide a method (100) of manufacturing a refractory (204) for continuous casting, the method comprising: forming (101), via freeze casting, a precursor structure (201) of the refractory; impregnating (102) the precursor structure (201) of the refractory with a carbon precursor (202); and pyrolysing (103) the impregnated precursor structure (203) of the refractory to form the refractory (204).