CN114920539B - High-toughness radiation-resistant aerogel heat-insulating material and preparation method thereof - Google Patents
High-toughness radiation-resistant aerogel heat-insulating material and preparation method thereof Download PDFInfo
- Publication number
- CN114920539B CN114920539B CN202210565319.3A CN202210565319A CN114920539B CN 114920539 B CN114920539 B CN 114920539B CN 202210565319 A CN202210565319 A CN 202210565319A CN 114920539 B CN114920539 B CN 114920539B
- Authority
- CN
- China
- Prior art keywords
- boron nitride
- radiation
- aerogel
- mixed solution
- toughness
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B30/00—Compositions for artificial stone, not containing binders
- C04B30/02—Compositions for artificial stone, not containing binders containing fibrous materials
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
- B01J13/0091—Preparation of aerogels, e.g. xerogels
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/00241—Physical properties of the materials not provided for elsewhere in C04B2111/00
- C04B2111/00258—Electromagnetic wave absorbing or shielding materials
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2201/00—Mortars, concrete or artificial stone characterised by specific physical values
- C04B2201/20—Mortars, concrete or artificial stone characterised by specific physical values for the density
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2201/00—Mortars, concrete or artificial stone characterised by specific physical values
- C04B2201/30—Mortars, concrete or artificial stone characterised by specific physical values for heat transfer properties such as thermal insulation values, e.g. R-values
- C04B2201/32—Mortars, concrete or artificial stone characterised by specific physical values for heat transfer properties such as thermal insulation values, e.g. R-values for the thermal conductivity, e.g. K-factors
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2201/00—Mortars, concrete or artificial stone characterised by specific physical values
- C04B2201/50—Mortars, concrete or artificial stone characterised by specific physical values for the mechanical strength
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/54—Improvements relating to the production of bulk chemicals using solvents, e.g. supercritical solvents or ionic liquids
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Dispersion Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Ceramic Products (AREA)
Abstract
The invention relates to a high-strength and high-toughness radiation-resistant aerogel heat-insulating material and a preparation method thereof, wherein the method comprises the following steps: uniformly mixing alumina nano powder, boron nitride nanosheets, an anti-radiation agent and a sulfuric acid solution by using water to obtain a mixed solution, and then placing the mixed solution at the temperature of 150-300 ℃ for hydrothermal reaction for 12-18h to obtain gel; the mass fraction of the alumina nano powder contained in the mixed solution is 5-20%, and the mass fraction of the boron nitride nano sheet contained in the mixed solution is 1-5%; sequentially carrying out aging, solvent replacement and supercritical drying on the obtained gel to obtain a boron nitride doped anti-radiation aerogel material; and carrying out heat treatment on the boron nitride-doped anti-radiation aerogel material to prepare the high-strength and high-toughness anti-radiation aerogel heat-insulating material. The invention obtains the anti-radiation aerogel heat insulation material which is tough, low in density and high in heat insulation efficiency.
Description
Technical Field
The invention relates to the technical field of aerogel preparation, in particular to a high-strength and high-toughness radiation-resistant aerogel heat-insulating material and a preparation method thereof.
Background
The nano porous aerogel (short for aerogel) material is a gel material with a gas as a dispersion medium, and is a nano porous solid material with a network structure formed by mutually accumulating colloidal particles or high polymer molecules, and the size of pores in the material is in the order of nanometers. The porosity of the porous material reaches 80-99.8%, the typical size of the pores is 1-100 nm, and the specific surface area is 200-1000 m 2 A density of as low as 3kg/m 3 And the room temperature thermal conductivity can be as low as 0.012W/m.k.Due to the characteristics, the aerogel material has wide application potential in the aspects of thermal, acoustic, optical, microelectronic and particle detection. Currently, the most widespread field of application of aerogels is still the field of thermal insulation, since the unique nanostructure of aerogels can effectively reduce convection conduction, solid phase conduction and thermal radiation.
The aerogel exhibits excellent low-temperature heat insulation properties by virtue of high porosity and fine skeleton, however, strong infrared radiation at high temperature reduces the heat insulation efficiency of the material at high temperature. Therefore, how to improve the radiation resistance becomes an important breakthrough point for improving the high-temperature insulation material. At the present stage, the infrared radiation performance of the material is mainly improved through two modes, firstly, the radiation resistance is reduced layer by layer through the design of the radiation-resistant screen, and finally, the heat-insulating performance is improved. The method has high requirements on the technological properties of the heat-insulating material and has limited application scenes. The other way is to dope the antiradiation agent, wherein the antiradiation agent comprises powder, whisker, fiber and the like, and the types comprise carbon black, silicon carbide, iron oxide and the like. The doping mode mainly needs to solve the problem of sedimentation of the anti-radiation agent.
In addition, most of the traditional aerogel materials are pearl necklace-shaped structures formed by accumulating nano particles, the aerogel materials with the structures are fragile, and fiber reinforcement is needed in practical application to realize structure reinforcement. However, the fiber reinforcement process will result in increased density, increased solid phase thermal conductivity and increased process complexity. In addition, some methods for strengthening the skeleton to prepare pure-phase aerogel materials have good structural strength, however, the method usually requires a high-temperature sintering process to increase the size of the skeleton to improve the strength of the materials, so that new problems of high thermal conductivity, high brittleness and the like are brought. The nano-cellulose can prepare nano-cellulose aerogel with a tough structure to a certain degree, but the organic components determine that the nano-cellulose aerogel has poor temperature resistance and is not suitable for heat insulation application. Therefore, the development of the nano aerogel material with good and tough structure has important significance.
With the development of science and technology, various fields put higher demands on the toughness, temperature resistance, light weight and heat insulation performance of heat insulation materials, so that an effective method for preparing a high-toughness and radiation-resistant aerogel heat insulation material is needed to be developed.
Disclosure of Invention
In order to solve one or more technical problems in the prior art, the invention provides a high-strength and high-toughness radiation-resistant aerogel heat-insulating material and a preparation method thereof.
The invention provides a preparation method of a high-strength and high-toughness radiation-resistant aerogel heat-insulating material, which comprises the following steps:
(1) Uniformly mixing alumina nano powder, boron nitride nanosheets, an anti-radiation agent and a sulfuric acid solution by using water to obtain a mixed solution, and then placing the mixed solution at the temperature of 150-300 ℃ for hydrothermal reaction for 12-18h to obtain gel; the mass fraction of the alumina nano powder contained in the mixed solution is 5-20%, and the mass fraction of the boron nitride nano sheet contained in the mixed solution is 1-5%;
(2) Sequentially carrying out aging, solvent replacement and supercritical drying on the gel obtained in the step (1) to obtain a boron nitride-doped anti-radiation aerogel material;
(3) And (3) carrying out heat treatment on the boron nitride doped anti-radiation aerogel material obtained in the step (2) to obtain the high-strength and high-toughness anti-radiation aerogel heat-insulating material.
Preferably, the particle size of the boron nitride nanosheet is 500nm-10 μm, and the thickness of the boron nitride nanosheet is 50-300 nm.
Preferably, the particle size of the boron nitride nanosheet is 1-2 μm.
Preferably, the particle size of the aluminum oxide nano powder is 10-100 nm; and/or the dosage of the anti-radiation agent is 1-50% of the mass of the alumina nano powder.
Preferably, the anti-radiation agent is silicon carbide nanoparticles, and the particle size of the silicon carbide nanoparticles is preferably 20-200 nm.
Preferably, the amount of the sulfuric acid solution is 0.8 to 7% of the total mass of the mixed solution.
Preferably, the concentration of the sulfuric acid solution is 0.1-30 mmol/L.
Preferably, the aging is: aging for 0.5-10h at 20-90 ℃.
Preferably, the supercritical drying is supercritical carbon dioxide drying, and preferably, the temperature of the supercritical drying is 20-60 ℃ and the pressure is 10-16MPa.
Preferably, the temperature of the heat treatment is 1000-1200 ℃, and the time of the heat treatment is 0.5-2 h; and/or the heat treatment is performed in a nitrogen atmosphere.
The invention provides a high-strength and high-toughness radiation-resistant aerogel thermal insulation material prepared by the preparation method in the first aspect.
Compared with the prior art, the invention at least has the following beneficial effects:
(1) Compared with the traditional pearl necklace aerogel material, the nano aerogel material has better mechanical strength, the nano aerogel material is constructed into a 'brick sand' structure, the microstructure of the high-toughness radiation-resistant aerogel heat-insulating material takes a network formed by mutually winding alumina nanowires as sand, and boron nitride nanosheets as bricks are embedded in the network formed by the alumina nanowires, so that the structural strength of the aerogel material is greatly improved, and the pure-phase aerogel still has good toughness without a relatively high-temperature sintering process.
(2) In the invention, the solution system adopts a sulfuric acid solution as an adsorbent, so that strong hydrogen bond action exists among nano particles, the action shows that the solution has the macroscopic performance of higher solution viscosity, the nano particles are weakly interacted to form a large network, the large network cannot settle, the added anti-radiation agent (such as silicon carbide nano particles) does not settle, and the uniformly dispersed anti-radiation agent doped aerogel material can be prepared; compared with the traditional method, the system effectively solves the problem of the sedimentation of the anti-radiation agent; the invention realizes the in-situ doping of the anti-radiation agent, and the anti-radiation agent is doped in the network formed by the mutual winding of the alumina nanowires in situ, thereby greatly improving the heat insulation efficiency of the material.
(3) The gel process in the preparation method of the aerogel is a hydrothermal process, is different from the traditional RTM (resin transfer molding) pressing glue injection process, is not limited by the shape and size of the reinforcement, and can be used for preparing aerogel materials with any shape and thickness.
(4) The invention provides the aerogel material with stable structure prepared in a nanowire self-supporting mode for high-temperature-resistant and high-efficiency heat insulation application, the improvement method is more feasible, and the nanowire aerogel material with good temperature resistance, toughness and low density can be obtained without a graded heat treatment process, so that the preparation method has the advantages of simple preparation process, short preparation period and the like.
(5) The invention can adopt water phase as reaction medium, and avoids environmental pollution and waste caused by using organic solvent in the preparation process.
(6) The density of the aerogel material prepared by the invention can be as low as 0.12g/cm 3 Compared with other low-density aerogel materials with the same strength, the aerogel material has the characteristic of ultralow density; the aerogel material prepared by the method has excellent high temperature resistance on the premise of keeping low thermal conductivity (as low as 0.024W/m.K), and can realize heat insulation application at 1100 ℃ for a long time.
(7) The porosity of the nano-wire aerogel heat-insulating material prepared by the method is about 95 percent, the diameter of a nano-wire unit contained in the prepared aerogel heat-insulating material is 20-50 nm, the length of the nano-wire unit is 5-30 mu m, the specific surface area is large, and the heat-resistant temperature is more than 1100 ℃.
Drawings
FIG. 1 is a flow chart of the preparation of the present invention.
FIG. 2 is a schematic structural diagram of "brick sand structure" of the high strength and toughness radiation resistant aerogel insulation material of the present invention.
FIG. 3 is an optical photograph of silicon carbide nanoparticles of the present invention uniformly dispersed in a mixed solution.
FIG. 4 is an optical photograph of the high strength and toughness radiation resistant aerogel insulation material prepared in example 1 of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
The invention provides a preparation method of a high-strength and high-toughness radiation-resistant aerogel heat-insulating material in a first aspect, which comprises the following steps:
(1) Uniformly mixing alumina nano powder, boron nitride nanosheets, an anti-radiation agent (such as silicon carbide nanoparticles) and a sulfuric acid solution by using water to obtain a mixed solution, and then putting the mixed solution at the temperature of 150-300 ℃ for a hydrothermal reaction for 12-18h (such as 12, 13, 14, 15, 16, 17 or 18 h) to obtain a gel; the mixed solution contains 5 to 20% by mass of alumina nano-powder (e.g., 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20%), and 1 to 5% by mass of boron nitride nano-sheet (e.g., 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5%); in the present invention, the gel is a semi-solid gel; the sources of the aluminum oxide nano powder, the boron nitride nano sheet and the silicon carbide nano particle are not particularly limited, and the product which can be directly purchased in the market can be adopted; in the invention, for example, the alumina nanopowder, the boron nitride nanosheet, the anti-radiation agent and the sulfuric acid solution are uniformly mixed with water by means of stirring (such as magnetic stirring) and/or ultrasound, and the conditions of stirring and ultrasound are not particularly required, so that the alumina nanopowder, the boron nitride nanosheet, the anti-radiation agent and the sulfuric acid solution are uniformly mixed in water; specifically, for example, after magnetic stirring for 1 to 24 hours, ultrasound for 1 to 4 hours, and in the ultrasound process, for example, stopping for 5 minutes every 10 minutes of ultrasound, and then continuing ultrasound; in some specific embodiments, for example, magnetic stirring is performed for 4 hours, followed by sonication for 2 hours; in the invention, the mixed solution is put into a closed container to carry out hydrothermal reaction for 12 to 18 hours at a temperature of between 150 and 300 ℃ to obtain semi-solid gel; in the present invention, the hydrothermal reaction is required to be carried out under a closed condition, and the material of the closed container is required to be a material which does not react with the system.
(2) Sequentially carrying out aging, solvent replacement and supercritical drying on the gel obtained in the step (1) to obtain a boron nitride-doped anti-radiation aerogel material; in the present invention, it is preferable that the aging is: aging the gel block in an oven at 20-90 ℃ for 0.5-10h, specifically, aging the gel block in a container in an air non-sealed environment at 20-90 ℃ for 0.5-10h, so that the gel block can slightly and slowly shrink in the air atmosphere, the strength of the gel block can be improved, and demolding is facilitated; the solvent substitution may employ, for example, ethanol as a solvent; the supercritical drying may be, for example, supercritical carbon dioxide drying.
(3) Carrying out heat treatment on the boron nitride-doped nanowire aerogel material obtained in the step (2) to prepare a high-strength and high-toughness radiation-resistant aerogel heat-insulating material; in the present invention, it is preferable that the heat treatment temperature is 1000 to 1200 ℃ and the heat treatment time is 0.5 to 2 hours.
In the invention, when the gel is prepared, a sulfuric acid solution is used as a catalyst, so that the finally obtained alumina nanowire aerogel can be ensured; in the invention, the anti-radiation agent (such as silicon carbide nanoparticles) is added into the raw materials for preparing the gel, so that the anti-radiation agent can be doped in a network formed by the alumina nanowires in situ; according to the invention, boron nitride nanosheets are added into the raw materials for preparing the gel, and the addition of the boron nitride nanosheets enables the nano aerogel material to be constructed into a brick sand structure (which can also be called as a shell-like structure), wherein the brick sand structure takes the boron nitride nanosheets as bricks and takes a network constructed by alumina nanowires as sand, and the special microstructure enables the aerogel in the invention to show structural characteristics of high strength in a macroscopic view; for example, chinese patent application CN111943704a discloses a method for preparing a reusable high temperature resistant nanocrystalline aerogel material, which effectively improves the structural strength of the high temperature resistant nanocrystalline aerogel, but needs to perform graded high temperature heat treatment at 500-700 ℃, 1100-1300 ℃ and a relative high temperature of 1200-1600 ℃ in sequence to achieve micro-toughening of the aerogel material, so that the structural strength of the aerogel material is significantly improved.
The invention discloses a preparation method of a gel, which is characterized in that boron nitride nanosheets instead of boron nitride nanopowders are added into the raw materials for preparing the gel, and the boron nitride nanosheets have a certain lamellar area and can be used as a reinforcement material to have a certain structural supporting force so as to increase the mechanical strength of the material; in addition, in the present invention, the mass fraction of the boron nitride nanosheets contained in the mixed solution needs to be controlled within a proper range, that is, the mass fraction of the boron nitride nanosheets contained in the mixed solution is controlled to be 1 to 5%, and the present invention finds that if the content of the boron nitride nanosheets is too small, the effect of improving the structural strength of the aerogel material is not significant, and if the content of the boron nitride nanosheets is too large, the thermal conductivity of the aerogel material is increased, and meanwhile, the content of the boron nitride nanosheets is too large, so that the alumina nanowires contained in the formed nanowire aerogel are separated by the boron nitride nanosheets and become discontinuous, which is also not beneficial to improving the strength of the aerogel material.
According to some preferred embodiments, the boron nitride nanoplates have a particle size (also referred to as plate size) of 500nm to 10 μm, preferably 1 to 2 μm, and a thickness of 50 to 300nm; in the invention, the thickness of the boron nitride nanosheet is in the nanometer level, so the boron nitride nanosheet is marked as the boron nitride nanosheet; in the invention, preferably, the particle size of the boron nitride nanosheet is 500nm-10 μm, and the invention finds that if the particle size of the boron nitride nanosheet is too small, the morphology of the boron nitride nanosheet is close to that of boron nitride nanopowder, the structure of the aerogel material cannot be well enhanced, and if the particle size of the boron nitride nanosheet is too large, the boron nitride is easily lapped and connected with each other in the aerogel to form a heat conduction passage, so that the heat insulation performance of the aerogel material is obviously adversely affected; in the invention, the thickness of the boron nitride nanosheet is preferably 50-300 nm, and it is found that if the thickness of the boron nitride nanosheet is too small, the boron nitride nanosheet is too thin, so that the boron nitride nanosheet is in a folded sheet shape, the strength of the boron nitride nanosheet is small, and the strength of the aerogel material is not favorably improved, and if the thickness of the boron nitride nanosheet is too large, the dimensions of the boron nitride nanosheet in three directions X, Y, Z are large, and the dimensions are equivalent to one boron nitride solid block, so that on one hand, the heat insulation performance of the aerogel material is reduced, on the other hand, the density of the material is also improved, and the aerogel material is not favorably provided with the characteristics of high efficiency, heat insulation and light weight.
According to some preferred embodiments, the boron nitride nanosheets in step (1) are modified boron nitride nanosheets prepared by: placing the boron nitride nanosheet in 45-50 wt% sodium hydroxide solution, performing ultrasonic treatment at 80-100 ℃, repeatedly washing and filtering with deionized water, and drying to obtain a modified boron nitride nanosheet; preferably, the sonication time is between 20 and 40min (e.g., 20, 25, 30, 35 or 40 min); in the invention, the deionized water is used for repeatedly washing and filtering, which means that the step of repeatedly washing and filtering is carried out by the deionized water until the washed water is neutral; in the invention, the boron nitride nanosheet is preferably the modified boron nitride nanosheet, and the invention finds that the surface of the boron nitride nanosheet treated by the sodium hydroxide solution contains more hydroxyl groups, so that the boron nitride nanosheet has better compatibility in a mixed solution for preparing gel, the boron nitride nanosheet can be well dispersed in an aqueous solution, and the hydroxyl groups on the surface of the boron nitride can form hydrogen bonds with the alumina nanowire, so that the boron nitride nanosheet is not easy to settle, and finally, the strength and the heat insulation performance of the aerogel material are better improved.
According to some preferred embodiments, the alumina nano powder has a particle size of 10 to 100nm.
According to some preferred embodiments, the anti-radiation agent is used in an amount of 1 to 50% (e.g., 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50%) by mass of the alumina nano powder, preferably 10 to 25% (e.g., 10%, 12%, 15%, 18%, 20%, 22%, or 25%); and/or the anti-radiation agent is silicon carbide nanoparticles, and preferably, the particle size of the silicon carbide nanoparticles is 20-200 nm.
According to some preferred embodiments, the sulfuric acid solution is used in an amount of 0.8 to 7% (e.g., 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, or 7%) of the total mass of the mixed solution; in the present invention, it is preferable that the amount of the sulfuric acid solution is 0.8 to 7% of the total mass of the mixed solution, and if the amount of the sulfuric acid solution is too large, the nanowires become short and thick, which is not favorable for the assembly process, may cause severe pulverization and shrinkage of the material, and may also cause weak strength of the material and increase the thermal conductivity.
According to some preferred embodiments, the concentration of the sulfuric acid solution is 0.1 to 30mmol/L (e.g., 0.1, 0.5, 1, 3, 5, 8, 10, 15, 20, 25, or 30 mmol/L); in the invention, the concentration of the sulfuric acid solution is preferably 0.1-30 mmol/L, and the invention finds that by adopting the sulfuric acid solution with the preferred concentration, compared with the sulfuric acid solution with high concentration, the nanowire with longer length-diameter ratio can be ensured, the formation of a gel block with stronger strength is facilitated, and the aerogel can be stronger after being dried.
According to some preferred embodiments, the aging is: aging for 0.5-10h at 20-90 ℃.
According to some preferred embodiments, the supercritical drying is supercritical carbon dioxide drying, preferably the supercritical drying is at a temperature of 20 to 60 ℃ and a pressure of 10 to 16MPa.
According to some preferred embodiments, the temperature of the heat treatment is 1000 to 1200 ℃ (e.g., 1000 ℃, 1050 ℃, 1100 ℃, 1150 ℃ or 1200 ℃) and the time of the heat treatment is 0.5 to 2 hours (e.g., 0.5, 1, 1.5 or 2 hours); and/or the heat treatment is performed in a nitrogen atmosphere. Preferably, the heat treatment temperature of the invention is only 1000-1200 ℃, and the structural toughness of the high-toughness radiation-resistant aerogel heat-insulating material can be further improved without carrying out graded heat treatment.
According to some specific embodiments, the preparation of the high-strength and high-toughness radiation-resistant aerogel thermal insulation material comprises the following steps:
(1) mixing aluminum oxide nano powder with the particle size range of 10-100nm, boron nitride nano sheets with the particle size of 500-10 mu m and the thickness of 50-300 nm, silicon carbide nano particles with the particle size of 20-200 nm and sulfuric acid solution with the concentration of 0.1-30 mmol/L into deionized water, firstly magnetically stirring for 1-24 h, and then carrying out ultrasonic treatment for 1-4 h (stopping for 5min every 10min of ultrasonic treatment, continuing the ultrasonic treatment) to obtain uniformly mixed liquid; in the mixed solution, the mass percent of the aluminum oxide nano powder is 5-20%, the mass percent of the boron nitride nano sheet is 1-5%, the dosage of the sulfuric acid solution accounts for 1% of the total weight of the mixed solution, and the dosage of the silicon carbide nano particles is 1-50% of the dosage of the aluminum oxide nano powder.
(2) Placing the mixed solution in a closed container, and performing hydrothermal reaction at 150-300 deg.C for 12-18h to obtain semisolid gel.
(3) Aging the gel in an oven at 20-90 ℃ for 0.5-10 h; the method specifically comprises the following steps: and (3) placing the gel block in a container, and aging in air in a non-sealed environment at the temperature of 20-90 ℃ for 0.5-10h.
(4) Carrying out a solvent replacement process and a supercritical drying step on the treated gel block obtained in the step (3) to prepare a boron nitride-doped anti-radiation aerogel material (also called as boron nitride-doped anti-radiation nanowire aerogel); the method comprises the following specific steps: the solvent replacement adopts ethanol as solvent, and the gel block is replaced for 3 times according to 10 times of the volume of the gel block, and then the supercritical carbon dioxide drying process is carried out, wherein the temperature of the supercritical drying is 20-60 ℃, and the pressure is 10-16MPa.
(5) And carrying out heat treatment on the boron nitride-doped anti-radiation nanowire aerogel material in a nitrogen atmosphere at the temperature of 1000-1200 ℃ for 0.5-2h to obtain the high-toughness anti-radiation aerogel heat-insulating material.
The invention provides a high-strength and high-toughness radiation-resistant aerogel thermal insulation material prepared by the preparation method in the first aspect.
The invention will be further illustrated by way of example, but the scope of protection is not limited to these examples.
Example 1
(1) Mixing aluminum oxide nano powder with the particle size range of 10-15nm, boron nitride nanosheets with the particle size range of 1-2 microns and the thickness range of 60-120 nm, silicon carbide nanoparticles with the particle size of 20-30 nm and a sulfuric acid solution with the concentration of 10mmol/L into deionized water, magnetically stirring for 4 hours, and then carrying out ultrasound for 2 hours (stopping for 5 minutes every 10 minutes in the ultrasound process, and then continuing ultrasound) to obtain a uniformly mixed solution; in the mixed solution, the mass percent of the aluminum oxide nano powder is 8%, the mass percent of the boron nitride nano sheet is 2%, the dosage of the sulfuric acid solution accounts for 1% of the total weight of the mixed solution, and the dosage of the silicon carbide nano particles accounts for 15% of the mass of the aluminum oxide nano powder.
(2) The mixed solution is put into a closed container to carry out hydrothermal reaction for 12 hours at 230 ℃ to obtain semisolid gel.
(3) And (3) placing the gel in a container, and aging for 2h in an oven at 60 ℃ under the air-non-airtight condition.
(4) Carrying out a solvent replacement process and a supercritical drying step on the treated gel block obtained in the step (3) to prepare the boron nitride-doped anti-radiation aerogel material; the method comprises the following specific steps: the solvent replacement adopts ethanol as a solvent, and after 3 times of replacement is carried out according to 10 times of the volume of the gel block, the supercritical carbon dioxide drying process is carried out, wherein the temperature of the supercritical drying is 50 ℃, and the pressure is 14MPa.
(5) And carrying out heat treatment on the boron nitride-doped anti-radiation aerogel material under the nitrogen atmosphere, wherein the heat treatment temperature is 1100 ℃, and the heat treatment time is 0.5h.
The high-strength and high-toughness radiation-resistant aerogel thermal insulation material prepared by the embodiment has good structural strength, and no light loss, no color change and no shedding on the surface of the aerogel thermal insulation material are found in a thermal insulation performance test.
The diameter of the nanowire unit contained in the prepared high-strength and high-toughness radiation-resistant aerogel heat-insulating material is 20-50 nm, and the length of the nanowire unit is 5-30 microns; the heat-resistant temperature of the aerogel heat-insulating material prepared in the embodiment is 1100 ℃. Wherein the heat-resistant temperature test is as follows: the aerogel heat insulation material finally prepared in each embodiment is subjected to heat treatment (nitrogen atmosphere) at a certain high temperature for 30min, and the linear shrinkage rate of the aerogel material is not more than 5%, which indicates that the aerogel heat insulation material can withstand the high temperature; for the present embodiment, the aerogel thermal insulation material prepared in the present embodiment is heat-treated at 1100 ℃ (in a nitrogen atmosphere) for 30min, the linear shrinkage rate of the aerogel material is not greater than 5%, and the heat-resistant temperature is 1100 ℃.
The compressive strength of the high-toughness radiation-resistant aerogel heat-insulating material prepared in the embodiment at 10% compression is 0.91MPa, and the test standard adopted in the compressive strength test of the invention is GB/T13480 2014 "determination of compressive performance of heat-insulating products for buildings".
Example 2
Example 2 is essentially the same as example 1, except that:
in the step (1), the particle size of the boron nitride nanosheet ranges from 6 to 10 microns, and the thickness ranges from 150 to 250nm.
The high-strength and high-toughness radiation-resistant aerogel heat-insulating material prepared by the embodiment has good structural strength, and when a heat-insulating property test is carried out, the surface of the aerogel heat-insulating material is found to have no light loss, no color change and no shedding.
Example 3
Example 3 is essentially the same as example 1, except that:
in the step (1), the particle size of the boron nitride nanosheet ranges from 1 to 2 μm, and the thickness ranges from 15 to 30nm.
Example 4
Example 4 is essentially the same as example 1, except that:
in the step (1), the particle size of the boron nitride nanosheet ranges from 1 to 2 microns, and the thickness ranges from 350 to 400nm.
Example 5
Example 5 is essentially the same as example 1, except that:
in the step (1), the particle size of the boron nitride nanosheet is in the range of 12-15 μm, and the thickness of the boron nitride nanosheet is in the range of 350-400 nm.
Example 6
Example 6 is essentially the same as example 1, except that:
in the step (1), in the mixed solution, the mass percentage of the alumina nano powder is 8%, and the mass percentage of the boron nitride nanosheet is 5.5%.
Example 7
Example 7 is essentially the same as example 1, except that:
in the step (1), the sulfuric acid solution is used at a concentration of 2mol/L.
Example 8
Example 8 is essentially the same as example 1, except that:
the step (1) is as follows: mixing aluminum oxide nano powder with the particle size range of 10-15nm, modified boron nitride nanosheets, silicon carbide nano particles with the particle size of 20-30 nm and a sulfuric acid solution with the concentration of 10mmol/L into deionized water, firstly magnetically stirring for 4 hours, and then carrying out ultrasonic treatment for 2 hours (in the ultrasonic treatment process, stopping for 5 minutes every 10 minutes of ultrasonic treatment, and then continuing the ultrasonic treatment), so as to obtain a uniformly mixed solution; in the mixed solution, the mass percent of the aluminum oxide nano powder is 8%, the mass percent of the modified boron nitride nano sheet is 2%, the use amount of the sulfuric acid solution accounts for 1% of the total weight of the mixed solution, and the use amount of the silicon carbide nano particles accounts for 15% of the mass of the aluminum oxide nano powder; wherein the preparation of the modified boron nitride nanosheet is as follows: placing the boron nitride nanosheet with the particle size range of 1-2 mu m and the thickness range of 60-120 nm in a sodium hydroxide solution with the concentration of 48wt% for ultrasonic treatment at 80 ℃ for 30min, then repeatedly washing and filtering the boron nitride nanosheet by using deionized water until the washing liquid is neutral after filtering, and drying the boron nitride nanosheet to obtain the modified boron nitride nanosheet.
Example 9
Example 9 is essentially the same as example 1, except that:
the step (1) is as follows: mixing aluminum oxide nano powder with the particle size range of 10-15nm, silicon carbide nano particles with the particle size range of 20-30 nm and a sulfuric acid solution with the concentration of 10mmol/L into deionized water, firstly magnetically stirring for 4 hours, and then carrying out ultrasound for 2 hours (in the ultrasound process, stopping for 5 minutes every 10 minutes of ultrasound, and continuing to carry out ultrasound), so as to obtain a uniformly mixed solution; in the mixed solution, the mass percentage of the aluminum oxide nano powder is 8%, the dosage of the sulfuric acid solution accounts for 1% of the total weight of the mixed solution, and the dosage of the silicon carbide nano particles accounts for 15% of the mass of the aluminum oxide nano powder.
The strength of the aerogel thermal insulation material prepared in this example is weaker than that of example 1, but the aerogel thermal insulation material can also form a complete block, and other performance indexes are shown in table 1.
Example 10
Example 10 is essentially the same as example 1, except that:
in step (1), an experiment was conducted using an acetic acid solution having a concentration of 10mmol/L instead of the sulfuric acid solution.
The aerogel thermal insulation material prepared by the embodiment has weak strength, the silicon carbide nanoparticles are not uniformly distributed, and a relatively complete block is not formed.
Example 11
Example 11 is essentially the same as example 1, except that:
in the step (1), the amount of the sulfuric acid solution is 0.5% of the total weight of the mixed solution.
The aerogel material that this embodiment made is weak in intensity, has the pulverization phenomenon, can't obtain the compressive strength under 10% compression to and can't obtain coefficient of thermal conductivity data.
Example 12
Example 12 is essentially the same as example 1, except that:
in the step (1), the amount of the sulfuric acid solution is 20% of the total weight of the mixed solution.
The aerogel material that this embodiment made is relatively weak in strength, has the pulverization phenomenon.
Example 13
Example 13 is essentially the same as example 1, except that:
the step (1) is as follows: mixing aluminum oxide nano powder with the particle size range of 10-15nm, boron nitride nano sheets with the particle size range of 1-2 mu m and the thickness range of 60-120 nm and a sulfuric acid solution with the concentration of 10mmol/L into deionized water, firstly magnetically stirring for 4 hours, and then carrying out ultrasound for 2 hours (in the ultrasound process, stopping for 5 minutes every 10 minutes of ultrasound, and then continuing to carry out ultrasound), so as to obtain a uniformly mixed solution; in the mixed solution, the mass percent of the aluminum oxide nano powder is 8%, the mass percent of the boron nitride nanosheet is 2%, and the dosage of the sulfuric acid solution accounts for 1% of the total weight of the mixed solution.
The aerogel thermal insulation material in the embodiment has a strong and tough structure and does not have the phenomena of powder falling and shedding.
Example 14
Example 14 is essentially the same as example 1, except that:
in the step (1), the amount of the silicon carbide nanoparticles is 50% by mass of the alumina nanopowder.
The aerogel thermal insulation material prepared by the embodiment has weak strength and has a powder falling phenomenon.
Example 15
Example 15 is essentially the same as example 1, except that:
(4) directly performing a supercritical carbon dioxide drying step on the treated gel block obtained in the step (3) without solvent replacement to prepare a boron nitride-doped anti-radiation aerogel material; the supercritical carbon dioxide drying temperature is 50 deg.C, and the pressure is 14MPa.
The aerogel heat-insulating material prepared by the embodiment is seriously pulverized and is difficult to form.
Example 16
Example 16 is essentially the same as example 1, except that:
in the step (4), normal pressure drying is adopted to replace the supercritical carbon dioxide drying process.
The aerogel material prepared by the embodiment has larger shrinkage and larger density.
Example 17
Example 17 is essentially the same as example 1, except that:
the heat treatment process of step (5) is not included.
Example 18
Referring to example 1 of chinese patent application CN111943704a, a high temperature resistant nanocrystalline aerogel material is prepared, and its performance index is shown in table 1.
The aerogel thermal insulation material finally prepared in each embodiment is subjected to performance test, and the performance indexes are shown in table 1.
In Table 1, the symbol "-" indicates that the performance index was not tested.
The invention has not been described in detail and is in part known to those of skill in the art.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (9)
1. The preparation method of the high-strength and high-toughness radiation-resistant aerogel heat-insulating material is characterized by comprising the following steps of:
(1) Uniformly mixing alumina nano powder, boron nitride nanosheets, an anti-radiation agent and a sulfuric acid solution by using water to obtain a mixed solution, and then carrying out hydrothermal reaction on the mixed solution at the temperature of 150 to 300 ℃ for 12 to 18h to obtain a gel; the mass fraction of the alumina nano powder contained in the mixed solution is 5-20%, and the mass fraction of the boron nitride nano sheet contained in the mixed solution is 1~5%; the particle size of the boron nitride nanosheet is 500nm to 10 mu m, and the thickness of the boron nitride nanosheet is 50 to 300nm; the dosage of the sulfuric acid solution accounts for 0.8 to 7 percent of the total mass of the mixed solution; the concentration of the sulfuric acid solution is 0.1 to 30mmol/L;
(2) Sequentially carrying out aging, solvent replacement and supercritical drying on the gel obtained in the step (1) to obtain a boron nitride-doped anti-radiation aerogel material;
(3) Carrying out heat treatment on the boron nitride-doped anti-radiation aerogel material obtained in the step (2) to obtain a high-strength and high-toughness anti-radiation aerogel heat-insulating material; the temperature of the heat treatment is 1000 to 1200 ℃, and the time of the heat treatment is 0.5 to 2h.
2. The method of claim 1, wherein:
the particle size of the boron nitride nanosheet is 1~2 μm.
3. The production method according to claim 1 or 2, characterized in that:
the particle size of the alumina nano powder is 10 to 100nm;
the dosage of the anti-radiation agent is 1 to 50 percent of the mass of the aluminum oxide nano powder; and/or
The anti-radiation agent is silicon carbide nanoparticles.
4. The production method according to claim 3, characterized in that:
the particle size of the silicon carbide nano-particles is 20 to 200nm.
5. The production method according to claim 1 or 2, characterized in that:
the aging is as follows: aging at 20 to 90 ℃ for 0.5 to 10 hours.
6. The production method according to claim 1 or 2, characterized in that:
the supercritical drying is supercritical carbon dioxide drying.
7. The method of claim 6, wherein:
the temperature of the supercritical drying is 20 to 60 ℃, and the pressure is 10 to 169Pc.
8. The production method according to claim 1 or 2, characterized in that:
the heat treatment is performed in a nitrogen atmosphere.
9. The high-strength and high-toughness radiation-resistant aerogel thermal insulation material prepared by the preparation method of any one of claims 1 to 8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210565319.3A CN114920539B (en) | 2022-05-23 | 2022-05-23 | High-toughness radiation-resistant aerogel heat-insulating material and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210565319.3A CN114920539B (en) | 2022-05-23 | 2022-05-23 | High-toughness radiation-resistant aerogel heat-insulating material and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114920539A CN114920539A (en) | 2022-08-19 |
| CN114920539B true CN114920539B (en) | 2023-03-10 |
Family
ID=82811359
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210565319.3A Active CN114920539B (en) | 2022-05-23 | 2022-05-23 | High-toughness radiation-resistant aerogel heat-insulating material and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114920539B (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108467253A (en) * | 2018-01-20 | 2018-08-31 | 南京航空航天大学 | A kind of silicon carbide nanometer line precast body enhancing alumina aerogels material and preparation method thereof |
| CN110282958A (en) * | 2019-07-12 | 2019-09-27 | 航天特种材料及工艺技术研究所 | Nanocrystalline aerogel material of a kind of high temperature resistant abnormity and preparation method thereof |
| CN111848140A (en) * | 2020-07-13 | 2020-10-30 | 航天特种材料及工艺技术研究所 | Alumina nanowire aerogel thermal insulation material and preparation method thereof |
| CN111925194A (en) * | 2020-08-18 | 2020-11-13 | 航天特种材料及工艺技术研究所 | High-temperature-resistant high-performance aerogel composite material and preparation method thereof |
| CN111943654A (en) * | 2020-08-18 | 2020-11-17 | 航天特种材料及工艺技术研究所 | High-temperature-resistant and radiation-resistant aerogel composite material and preparation method thereof |
| CN113648940A (en) * | 2021-09-23 | 2021-11-16 | 航天特种材料及工艺技术研究所 | Ultra-light high-elasticity radiation-resistant nanofiber aerogel material and preparation method thereof |
| CN114180988A (en) * | 2020-09-14 | 2022-03-15 | 南京工业大学 | Preparation method of high-temperature-resistant aerogel heat insulation sheet |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9208919B2 (en) * | 2012-02-03 | 2015-12-08 | Massachusetts Institute Of Technology | Aerogels and methods of making same |
-
2022
- 2022-05-23 CN CN202210565319.3A patent/CN114920539B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108467253A (en) * | 2018-01-20 | 2018-08-31 | 南京航空航天大学 | A kind of silicon carbide nanometer line precast body enhancing alumina aerogels material and preparation method thereof |
| CN110282958A (en) * | 2019-07-12 | 2019-09-27 | 航天特种材料及工艺技术研究所 | Nanocrystalline aerogel material of a kind of high temperature resistant abnormity and preparation method thereof |
| CN111848140A (en) * | 2020-07-13 | 2020-10-30 | 航天特种材料及工艺技术研究所 | Alumina nanowire aerogel thermal insulation material and preparation method thereof |
| CN111925194A (en) * | 2020-08-18 | 2020-11-13 | 航天特种材料及工艺技术研究所 | High-temperature-resistant high-performance aerogel composite material and preparation method thereof |
| CN111943654A (en) * | 2020-08-18 | 2020-11-17 | 航天特种材料及工艺技术研究所 | High-temperature-resistant and radiation-resistant aerogel composite material and preparation method thereof |
| CN114180988A (en) * | 2020-09-14 | 2022-03-15 | 南京工业大学 | Preparation method of high-temperature-resistant aerogel heat insulation sheet |
| CN113648940A (en) * | 2021-09-23 | 2021-11-16 | 航天特种材料及工艺技术研究所 | Ultra-light high-elasticity radiation-resistant nanofiber aerogel material and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114920539A (en) | 2022-08-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110282958B (en) | High-temperature-resistant special-shaped nanocrystalline aerogel material and preparation method thereof | |
| CN111925194B (en) | High-temperature-resistant high-performance aerogel composite material and preparation method thereof | |
| CN111252789B (en) | High-temperature-resistant alumina nanocrystalline aerogel material and preparation method thereof | |
| CN111848140B (en) | Alumina nanowire aerogel thermal insulation material and preparation method thereof | |
| CN108249901B (en) | Preparation method of high-temperature-resistant aerogel material | |
| CN111943704B (en) | Reusable high-temperature-resistant nanocrystalline aerogel material and preparation method thereof | |
| CN113831581B (en) | High-elasticity anti-radiation nanofiber aerogel material and preparation method thereof | |
| CN113663611B (en) | High-temperature-resistant composite nanofiber aerogel material and preparation method thereof | |
| CN114524638B (en) | Ultralow-thermal-conductivity nanofiber aerogel composite material and preparation method thereof | |
| CN111807810A (en) | Preparation method of nanowire/silicon-aluminum aerogel composite material | |
| CN114853453B (en) | Hydrophobic ceramic aerogel material with micro-nano structure and preparation method thereof | |
| CN108218467B (en) | Preparation method of porous nano silicon carbide ceramic with high porosity and low thermal conductivity | |
| CN113648940B (en) | Ultra-light high-elasticity anti-radiation nanofiber aerogel material and preparation method thereof | |
| CN114920539B (en) | High-toughness radiation-resistant aerogel heat-insulating material and preparation method thereof | |
| CN114804199B (en) | Titanium dioxide-alumina aerogel material and preparation method thereof | |
| Ding et al. | Optimization of ultralight SiO2/TiO2 nanofibrous aerogel for high-temperature application | |
| CN114804816B (en) | High-temperature-resistant high-toughness nanowire aerogel material and preparation method thereof | |
| CN114870757B (en) | High-temperature-resistant micro-nanofiber composite aerogel material and preparation method thereof | |
| CN105777177A (en) | Method for preparing aluminum oxide and chrome oxide hybrid aerogel composite | |
| CN105753446A (en) | Preparation method of aluminum oxide and copper oxide hybrid aerogel composite material | |
| CN114853457B (en) | Alumina-carbon composite nanofiber aerogel material and preparation method thereof | |
| CN115246745B (en) | High-temperature-resistant composite component aerogel material and preparation method thereof | |
| Ren et al. | Study on Silica Aerogel Modified by Trimethylchlorosilane | |
| CN105709669A (en) | Preparation method of germanium oxide and aluminum oxide hybrid aerogel composite material | |
| CN105777176A (en) | Method for preparing germanium oxide and zirconium oxide hybrid aerogel composite |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |