951 results about "Supercritical drying" patented technology

The invention provides a silicon-aluminium aerogel composite material, comprising (1) silicon-aluminium compound aerogel and (2) inorganic fiber material. The invention further provides a method for manufacturing silicon-aluminium aerogel composite material with simple technology, comprising the steps of preparing silica sol, preparing aluminium sol, preparing silicon-aluminium compound sol, dipping sol, gelatinizing, ageing, overcritical drying, etc. With excellent high-temperature resistant performance, nice mechanical property and lower thermal conductivity at high temperature, the silicon-aluminium aerogel composite material can meet the high demand of thermal protection in respect of aviation, space flight and military affairs and can be applied to the civil heat insulation field.

The invention discloses a method for preparing graphene aerogel and graphene / metallic oxide aerogel. The method is characterized in that graphite oxide aqueous solution serves as a raw material, alcohol serves as a cross-linking agent, a precursor solution is obtained through the simple mixing and dispersing processes, the hydrothermal method is adopted, the freeze drying method or a supercritical drying method is adopted, and then the graphene aerogel is obtained . The graphene / metallic oxide aerogel can be prepared by adding metallic oxide into the polymeric precursor solution. On one hand, the graphene vinyl aerogel material has the characteristic of the graphene aerogel, and on the other hand, the graphene vinyl aerogel material can have the physicochemical characteristic of the metallic oxide. In addition, the aerogel material has a large specific surface and good electrical conductivity, can directly serve as a supercapacitor electrode, and has large specific capacity, good rate capability and cycling stability. The materials used in the method are low in cost, the industrial process is simple, and the method is friendly to the environment.

The invention discloses a method for preparing super-hydrophobic silica aerogel at the normal pressure by taking an inorganic silicon source or an organic silicon source as a raw material. The method comprises the following steps: taking the inorganic silicon source or the organic silicon source as the raw material, then mixing the raw material with a solvent and a catalyst, and obtaining wet gel through a process of sol-gel, and then carrying out ageing, solvent replacement, surface modification and ambient pressure drying on the obtained wet gel to obtain the silica aerogel with low-density, high specific table and super hydrophobicity. The invention realizes the ambient pressure drying of the wet gel, avoids the equipment investment when the conventional supercritical drying is adopted, greatly improves the safety of the production, has simple operation, good properties and controllability of the products, and is suitable for large-scale production.

The invention relates to a method for preparing graphene crosslinked type organic aerogel and carbon aerogel by normal-pressure drying, which takes phenols (P), amines, aldehydes, catalyst and solvent as a reaction system and graphene substances containing active functional groups as a cross-linking agent. The method comprises the steps of: curing to obtain organogel, and then carrying out normal-pressure drying to obtain the organic aerogel; and carrying out pyrolysis on the organic aerogel in the inert atmosphere at the temperature of 500-1600 DEG C to obtain the graphene crosslinked type carbon aerogel. The preparation method of the organic aerogel and the carbon aerogel is simple and rapid in technology; the conventional supercritical drying technology is avoided, and the prepared novel organic aerogel and carbon aerogel materials taking graphene as framework have new performances and wide application prospect; and the industrial production of the carbon aerogel can be expected to be realized.

The invention relates to a preparation method of a silicon-carbide-fibrofelt-enhanced silica aerogel composite material, and relates to an aerogel composite material. According to the invention, a carbon-rich silicon carbide micro-nano ceramic fibrofelt with small fiber diameter, high porosity, communicating pores, fast impregnation speed, and good compatibility with a substrate is prepared with a static electro-spinning technology combined with a precursor conversion method; a silica sol is prepared with an acid-alkali two-step method; with an infiltration technology, the electro-spun silicon carbide ceramic fibrofelt or precast is soaked into the sol; and through processes such as gel process, aging, curing, solvent exchange, supercritical drying, and the like, the silicon-carbide-fibrofelt-enhanced silica aerogel composite material is obtained. The prepared composite material has the characteristics of low density, large specific surface area, super-hydrophobicity, low thermal conductivity, and the like. The strength and toughness of the material are also greatly improved. The carbon-rich silicon carbide fiber has an infrared shielding effect, such that composite material thermal insulation effect and ultra-high-temperature stability can be improved.

A method for preparing carbon aerogels and carbon aerogels obtained therefrom are disclosed. The method for preparing carbon aerogels comprises: mixing organic starting materials including phloroglucinol and furfural with a solvent capable of dissolving the organic materials in a predetermined ratio to form a sol solution; adjusting pH of the sol solution adequately by using an acidic or basic catalyst, gelling the sol solution at room temperature under atmospheric pressure, and aging the resultant gels; substituting the solvent in thus obtained gels with liquid carbon dioxide, followed by drying in a supercritical state, to form organic aerogels; and pyrolyzing the organic aerogels in an electric furnace under inert atmosphere to obtain carbon aerogels. Particularly, the gels are formed at room temperature in a short period of time by adequately adjusting pH of the sol solution. Therefore, the method provides improved time efficiency and energy efficiency as compared to existing methods for preparing gels. Additionally, the method allows supercritical drying while avoiding a need for an additional solvent substitution, thereby simplifying the overall process. Further, the method enables preparation of carbon aerogels for supercapacitors having a high specific surface area and high capacitance even in the absence of additional activation step.

A method for preparing fiber toughness SiO2 aerogel composite material in normal pressure drying condition relates to a preparation method of fiber toughness SiO2 aerogel composite material. The method solves the problem that a supercritical drying method for preparing large-size fiber toughness SiO2 aerogel has over-high requirements on device conditions. The preparation method of fiber toughnesscomposite material comprises the following steps: obtaining fiber toughness SiO2 aerogel composite material after sol-gel, ageing, solvent displacement, surface decoration, washing and drying processing. The method is characterized by low production cost, low requirements on device, good safety and the like. The fiber toughness SiO2 aerogel composite material prepared by the method can be made into flexible and rigid composite material according to the form and characteristics of a fiber prefabricated part, has complete block and low thermal conductivity, and is hydrophobing. The fiber toughness SiO2 aerogel composite material has wide application prospect in the heat preservation and insulation field.

The invention discloses a transparent high-strength fiber material. The preparation method comprises the following steps that: cellulose is dissolved in NaOH-urea aqueous solution or LiOH-urea aqueous solution which is pre-cooled at low temperature to obtain a cellulose solution, and different thicknesses of cellulose hydrogels are prepared by the cellulose solution; water in the cellulose hydrogel is replaced into an organic solvent to obtain a cellulose organic gel; the cellulose hydrogel or the cellulose organic gel is subject to supercritical drying, ambient pressure drying or freeze drying to remove a liquid medium so as to obtain a cellulose aerogel; and the cellulose hydrogel, the organic gel or the aerogel are autoclaved at a temperature of 30-200 DEG C under the pressure of 10-160Mpa to obtain the high-strength transparent cellulose material. The cellulose material prepared by the invention has excellent mechanical properties, thermal stability and optical permeability.

The invention discloses a low-density aerogel composite material and block-shaped low-density gel insulating composite material through packing the low-density aerogel composite material, which comprises the following steps: utilizing high-polymerization degree polyacrylic acid as porous nanometer silica reinforced frame to make the silica gel and composite material with certain elasticity and contractility; inhibiting crack during gel preparing course and hyper-critical drying course effectively; adopting packing slurry with alumina, titania, carborundum, hollow glass microball or ferroferric oxide and soluble silicate, organosilicon resin or silica gel to pack the surface of large block of silica aerogel; sintering the packed aerogel composite material at 650-700 deg. c; using the material under 1000 deg. c at most.

The invention discloses a method for preparing silicon dioxide aerogel with low density and large specific surface area at ordinary pressure. The method comprises the steps of taking cheap industrial water glass as a precursor and absolute ethyl alcohol as a solvent, performing hydrolysis and polycondensation reaction by the catalysis of acid and alkali respectively to form wet gel, performing water bath drying and aging, performing solvent exchange for many times, and performing graded drying at the ordinary pressure after surface modification to form the silicon dioxide aerogel with the low density. According to the method, the completely modified super hydrophobic silicon dioxide aerogel is obtained by using the least amount of modifier; the cheap industrial water glass is adopted as a silicon source, so that the production cost is greatly lowered; and the energy source is greatly saved for drying at the ordinary pressure in comparison with supercritical drying.

The invention provides an oriented fiber aerogel heat-insulating compound material and a preparation method thereof, belonging to the technical field of functional materials, and heat insulation and energy conservation. The oriented fiber aerogel heat-insulating compound material comprises a fiber skeleton and aerogel, wherein the aerogel is filled in the fiber skeleton; and fibers in the fiber skeleton are tidily arranged in the same direction, and the fiber skeleton is an oriented fiber skeleton. The oriented fiber aerogel heat-insulating compound material has a superhigh heat-insulating performance (the coefficient of heat conductivity is 0.013 W / m.K) and good pressure resistance and fracture resistance, and the heat-insulating performance, the pressure resistance and the fracture resistance are directionally controllable; the oriented fiber aerogel heat-insulating compound material can be widely applied to fields which require heat-insulating and heat-preserving measures; and the preparation method adopts a normal-pressure drying technology and a supercritical drying technology in the conventional aerogel preparing process is not used, so that the preparation cost of the aerogel heat-insulating compound material can be greatly reduced and the aerogel heat-insulating compound material is applicable to industrial production.

A method of depositing a metal film on a substrate includes a supercritical preclean step, a supercritical desorb step, and a metal deposition step. Preferably, the preclean step includes maintaining supercritical carbon dioxide and a chelating agent in contact with the substrate in order to remove an oxide layer from a metal surface of the substrate. More preferably, the preclean step includes maintaining the supercritical carbon dioxide, the chelating agent, and an acid in contact with the substrate. Alternatively, the preclean step includes maintaining the supercritical carbon dioxide and an amine in contact with the oxide layer. The desorb step includes maintaining supercritical carbon dioxide in contact with the substrate in order to remove adsorbed material from the substrate. The metal deposition step then deposits the metal film on the substrate without exposing the substrate to an oxidizing material which oxidizes the metal surface of the precleaned substrate and without exposing the substrate to a nonvolatile adsorbing material which adsorbs to the substrate. An apparatus for depositing the metal film on a substrate includes a transfer module, a supercritical processing module, a vacuum module, and a metal deposition module. The supercritical processing module is coupled to the transfer module. The vacuum module couples the metal deposition module to the transfer module. In operation, the apparatus for depositing the metal film performs the supercritical preclean step, the supercritical desorb step, and the metal deposition step.

This invention provides a preparation method for a high ratio surface area carbon gel, which takes resorcin and formaldehyde as the raw materials, sodium carbonate as the catalyst to prepare carbon gel by sol-gel reaction and ordinary pressure and high temperature carbonization and takes CO2 as the activating agent to carry out gas activation process to get the high ratio surface area carbon gel, which avoids the traditional complicated technology of exceeding critical dryness and makes up the shortcomings of low ratio surface area brought with the normal pressure dryness.

The invention relates to a method for preparing a fiber-containing silicon dioxide aerogel composite thermal insulation material. The method is mainly characterized by comprising the following steps of: adding fiber and an infrared sunscreen agent into aerogel precursor solution to form composite gel, and treating the composite gel to obtain fiber-containing silicon dioxide aerogel composite powder; and adding a little binding agent and performing compression molding by adopting a half-dry pressing method, and performing heat treatment to obtain composite products in various shapes. By adopting a technical route for preparing the composite powder and molding by adopting the half-dry pressing method, products in complex shapes are easy to produce, supercritical drying at high cost and in danger of high pressure is avoided, and the method is easy for mass production. By taking industrial silica sol and industrial spirit as main raw materials for preparing silicon dioxide aerogel, addinga drying controlled chemical additive, the infrared sunscreen agent and the fiber in turn and finally slowly adding the industrial spirit until gelling, the fiber and the infrared sunscreen agent canbe fully and uniformly mixed with the aerogel in the composite powder, the thermal insulation of the materials is improved, and a higher-strength light thermal insulation material is prepared.

The invention provides a fiber-reinforced silicon-dioxide aerogel heat insulation composite material and a preparation method thereof. According to the preparation method, mineral fibers with high mechanical strength, low heat conductivity and good heat stability serve as a reinforcing phase, silicon alcoholate serves as a precursor, fiber-composite silicon-dioxide wet gel is prepared by adopting an acid-base two-step catalysis method, and the block-shaped fiber-reinforced silicon-dioxide aerogel heat insulation composite material is then obtained through aging, modification, solvent displacement and supercritical drying. The prepared aerogel heat insulation composite material has the advantages of excellent mechanical property, good heat-insulating property and higher heat resistance. The aerogel composite material has a three-dimensional porous network-like structure, the compatibility between fibers and an aerogel matrix is good, the interfacial bonding is firm, and no obvious interfaces exist; and according to the block-shaped aerogel composite material, the density is 0.15-0.25 g / cm<3>, the compressive strength is 10%, the strain energy reaches 0.4-2.0MPa, and the coefficient of heat conductivity is 0.016-0.027 W / mK.

The invention discloses a hydrophilic graphene-carbon nano-tube composite super-light elastic aerogel and a preparation method thereof. The preparation method comprises the following steps: firstly preparing a graphene oxide-carbon nano-tube dispersion liquid; then adding a polymer aqueous solution into the graphene oxide-carbon nano-tube dispersion liquid to obtain a three-phase composite dispersion liquid; and then freeze drying or supercritical drying the three-phase composite dispersion liquid, adopting chemical reduction or high-temperature reduction to obtain the hydrophilic graphene-carbon nano-tube composite super-light elastic aerogel. The hydrophilic graphene-carbon nano-tube composite super-light elastic aerogel and the preparation method are simple in technology and green and environment-friendly in process; the prepared hydrophilic graphene-carbon nano-tube composite super-light elastic aerogel has the advantages of low density, hydrophilicity, high elasticity and the like.

The invention provides a silicon-aluminum aerogel composite material which comprises silicon-aluminum composite aerogel (1) and an inorganic fiber material (2), wherein the silicon-aluminum composite aerogel is prepared from a silicasol aqueous solution. The invention also provides a method for preparing the silicon-aluminum aerogel composite material, which comprises the steps of preparing the silicon-aluminum composite aerogel, dipping sol, gelatinizing, ageing, overcritically drying and the like. With excellent high-temperature resistance, good mechanical property and low thermal conductivity at high temperature, the silicon-aluminum aerogel composite material can meet the high requirement of thermal protection in the fields of aviation, aerospace and military affairs and can also be applied to the field of civil heat insulation.

The invention discloses an ambient pressure drying method for rapidly preparing SiO2 aerogel. Part of an alcohol solvent is replaced with a solvent with low surface tension; silica-alkoxides, the non-replaced alcohol solvent, an acidic catalyst, a basic catalyst and the solvent with the low surface tension are prepared into sol according to a certain proportion, after alcogel containing the solvent with the low surface tension is formed, ageing and surface modification processes are carried out, and then, ambient pressure drying is directly carried out, so that the complex solvent exchanging step is omitted, and the SiO2 aerogel is prepared within 30h. By using the method, not only are the defects such as high equipment investment, low efficiency, high cost of the traditional supercritical drying process overcome, but also the problems of long period, high using cost for solvent exchanging and the like in the traditional ambient pressure drying process are solved, and the prepared SiO2 aerogel has the characteristics of low surface density, large specific area, large pore volume and the like.

The invention relates to a preparation method of nanometer aerogel heat-insulation coating, which comprises the following steps: dissolving aerogel, solidifying the aerogel, aging, replacing by a surface modification solvent, drying at normal pressure and preparing lyophobic silicon dioxide aerogel; or supercritically drying and preparing hydrophilic silicon dioxide aerogel. The preparation method provided by the invention has the beneficial effects that the aperture of the silicon dioxide aerogel prepared by adopting the method provided by the invention is in nanometer-level distribution, and the main aperture of the silicon dioxide aerogel is10nm and is less than the free path of an air molecular movement, thereby greatly reducing the heat transfer generated by a gas molecular heat movement; the aerogel in the invention is in a network structure formed by overlapping the spherical granules of nanometer silicon dioxide, thereby reducing the contact area of solid granules, increasing the heat transfer path and further achieving the effects of heat maintenance and heat insulation; and lyophobic and hydrophilic type silicon dioxide aerogel can be prepared according to different drying processes to be used by matching organic or inorganic coatings.

The invention discloses a high-efficiency insulating material capable of being used for a high-temperature pipeline with insulation requirements. The high-efficiency insulating material comprises thefollowing mixed raw materials by weight percentage: 40 to 80 percent of nano SiO2 powder, 5 to 40 percent of infrared opacifier and 0 to 25 percent of reinforcing fiber. The high-efficiency insulatingmaterial is formed by adopting a drying method and overcomes the defect that the sol-gel method for preparing an aerogel-based material needs supercritical drying. The high-efficiency insulating material is designed by a microstructure, carries out full restriction on heat conduction, convection and radiant heat transfer at high temperature simultaneously and leads the heat-conducting coefficientof material under the use temperature to be lower than that of static air.

A method and system for processing a substrate includes performing a wet process by supplying a working liquid to a substrate in a wet processing apparatus, transferring the substrate in a non-dry state from the wet processing apparatus to a drying apparatus, and subjecting the substrate to a supercritical drying by a supercritical fluid in the drying apparatus.

The invention provides a preparation method of a nitrogen-doped graphene aerogel supported non-precious metal oxygen reduction catalyst. The method comprises the following steps: stirring a mixed solution of organic amine and aldehyde for 0.5-2 hours at the temperature of 50-90 DEG C, adding graphene oxide and a non-precious salt solution, stirring for 1-24 hours at the temperature of 60-99 DEG C to obtain organogel, performing freezing or supercritical drying, heating to 500-1000 DEG C under protection of inert gas, preserving heat for 1-6 hours, and naturally cooling to room temperature, thereby obtaining the nitrogen-doped graphene aerogel supported non-precious metal oxygen reduction catalyst. The preparation method of the nitrogen-doped graphene aerogel supported non-precious metal oxygen reduction catalyst is simple, the production can be easily expanded, the cost is low, the oxygen reduction catalysis activity is high, and the commercial popularization is facilitated.

The invention provides a SiO2 nanoscale porous material with aerogel property prepared by microwave reaction and a preparation method thereof; the nanoscale porous material comprises silicon dioxide skeletons (1) and bubble-shaped nanoscale pores (2), wherein the foam-shaped nanoscale pores (2) are arranged among the silicon dioxide skeletons (1). The preparation method comprises four steps, namely preparation of silicon dioxide sol, preparation of wet gel, aging of mother solution and drying at normal pressure and the preparation of silicon dioxide sol comprises the following steps: adopting organosiloxane, organic solvent, water and acid catalysis as raw materials; mixing each components in a defined ratio in a container while adopting microwave radiation to perform hydrolytic polycondensation reaction or adopting microwave radiation to perform hydrolytic polycondensation reaction after mixing the components. Owning to adopting microwave radiation technology, a lot of bubbles are generated in silicon dioxide sol, a large quantity of nanoscale bubble-shaped pores are formed on the silicon dioxide substrate, and meanwhile silicon dioxide space skeletons are retained so that silicon dioxide porous material with extremely large specific area and higher intensity can be obtained. In addition, because carbon dioxide supercritical drying process is not needed, the production cost is greatly reduced.

The invention provides a method for preparing a graphene aerogel through constant pressure drying. The method comprises the following steps of: firstly, preparing a hydrogel by using aqueous dispersions of oxidized graphene as raw materials; processing the hydrogel by freezing and melting so as to reassemble the internal structure of the hydrogel, wherein the formed structure is strong enough to resist the structure collapse caused by air-liquid interface tension during constant pressure drying; and finally, realizing the preparation of the graphene aerogel through constant pressure drying. Compared with a freeze drying method and a supercritical drying method, the method disclosed by the invention has the advantages that the efficiency for preparing the graphene aerogel is greatly improved, the production cost is reduced, and the industrialized production of the graphene aerogel is hopeful to realize. In addition, the invention further provides a novel graphene aerogel, and the characteristics of macropores and super resilience, of the graphene aerogel, can be applied in many fields.

Processes for producing gel compositions comprising: esterifying a portion of the surface of a gel composition sufficient to produce a gel composition having a rod density of less than or equal to 0.15 g / cc, and / or a tap density of less than or equal to 0.2 g / cc through contact with at least one esterification agent and at least one catalyst. The processes may be utilized to produce low density gel compositions without the need for a supercritical drying step or thermal treatment.

The invention discloses a rapid preparation method for an aerogel material. The preparation method is a combination of a sol-gel method and a supercritical drying process. According to the invention, wet gel is formed through the sol-gel method at first and is directly put into a container for sealing without ageing; then the sealed container is put into a supercritical drying device and a supercritical medium solvent is added; and the supercritical drying process is carried out so as to prepare the aerogel material. Compared with the prior art, the preparation method provided by the invention has the following advantages: the ageing procedure in general aerogel preparation is eliminated, so the preparation period for the aerogel material is greatly shortened; and the wet gel does not need to soak in the medium solvent, so the consumption of the medium solvent in preparation is reduced. The aerogel prepared by using the method has an intact skeleton structure and a non-shrink volume.

The invention relates to a preparation method of blocky ZrO2 aerogel. According to the preparation method, ZrO2 aerogel is prepared from zirconium inorganic salt by means of combination of the anion exchange technique and the sol-gel technique and by using epoxides as gel accelerators, and the blocky ZrO2 aerogel which is high in strength, low in density and low in heat conductivity coefficient is prepared by adding chelants, dispersing agents, drying controlling agents and the like to adjust uniformity of gel networks and pore structures, using the gel aging technique to improve and reinforce gel network frame strength and combining the high-temperature supercritical drying technique. The method is used for preparing the high-performance blocky ZrO2 aerogel from the cheap zirconium inorganic salt which is harmless to human bodies, so that the blocky ZrO2 aerogel has wide application prospect in the field of high-temperature thermal-insulation materials.

The present invention belongs to the field of inorganic non-metal material, and is especially the preparation process of heat insulating composite nanometer pore calcium silicate material. The preparation process includes first preparation of block, tubular and tile-like product comprising secondary particle of superfine xonotlite crystal; the preparation of SiO2 gel precursor; pouring the gel precursor into porous xonotlite product; letting stand for gelation and ageing and supercritical drying in high pressure autoclave. By means of the compounding of hard support skeleton of superfine xonotlite fiber with hollow secondary pellet and SiO2 aerosol, the present invention has greatly lowered heat conducting coefficient and greatly raised strength.

The invention relates to a heat-resisting silica aerogel material and a preparation method thereof. SiO2 sol is prepared by adopting a sol-gel method, modified liquid is innovatively led to a supercritical drying process by ageing and solvent replacement through adopting a supercritical modification process, so as to obtain bulk aerogel which is high in mechanical strength and easy to process, and then the SiO2 aerogel of which linear contraction just is 5%, and the specific surface area can be up to 530m<2> / g after high-temperature treatment at 1000 DEG C can be obtained by high-temperature pretreatment at 800 DEG C and gas-phase modification of hexamethyldisilazane. By adopting the synthetic method, application of the SiO2 aerogel in high-temperature fields such as high-temperature catalysis, a catalyst carrier and high-temperature heat preservation and insulation is greatly facilitated.

The invention discloses a method for preparing potassium hexatitanate whisker composite SiO2 aerogel thermal insulation material, which comprises the steps of adopting a potassium hexatitanate whisker as a reinforcing phase, utilizing a coupling agent for the surface modification of the potassium hexatitanate whisker, preparing a SiO2 gel precursor at the same time, mixing and stirring the modified potassium hexatitanate whisker and the SiO2 gel precursor, keeping stand to gelatinate, aging to obtain SiO2 gel containing the potassium hexatitanate whisker, then performing supercritical drying and heat treatment through a high pressure kettle, and obtaining the potassium hexatitanate whisker composite SiO2 aerogel thermal insulation material. The composite thermal insulation material has good barrier function on solid heat transfer and air convection heat transfer, can effectively block infrared radiation heat transfer at the same time, has heat conductivity coefficient of between 0.01 and 0.015w / m.k at normal temperature, and improves 3 to 5 times of strength than SiO2 aerogel. The method has wide application range, and can meet operating requirements of more harsh thermal protection conditions of aviation, spaceflight, military affairs and civil use.