97 results about "MAX phases" patented technology

The invention discloses a broadband wave-absorbing material based on an MAX-phase metasurface structure and an impedance matching optimization method of the broadband wave-absorbing material. The wave-absorbing material comprises an MAX-phase ceramic substrate and periodic metasurface structures which are arranged on the surface of the MAX-phase ceramic substrate in an array mode and composed of conductive resonance units. The resonance units are isolated through gaps, an equivalent R1L1C1 series resonance circuit is formed in an electromagnetic field, and a base body is equivalent to a parallel resistor R2. By establishing an equivalent circuit model and optimizing parameters R1, L1, C1 and R2, impedance matching of the wave-absorbing material in a target frequency band can be regulated and controlled, so that the wave-absorbing material at least has an absorption peak of which the reflection loss is less than-10 dB. According to the optimization method, electromagnetic simulation and circuit simulation are combined, optimized circuit parameters are reversely mapped into structure geometric parameters, material preparation is guided, and accurate design and broadband absorption of the wave absorbing performance are achieved.

A hardened alloy composite material comprising an alloy matrix and reinforcing particles dispersed in the alloy matrix, the reinforcing particles having a shell and core structure, wherein the shell and the core have different chemical compositions, and wherein the reinforcing particles are formed by a MAX phase compound and / or a MAB phase compound.

The invention discloses Si-based MAX phase powder and a preparation method thereof, and belongs to the technical field of ceramic material preparation. The preparation method of the Si-based MAX phase powder comprises the following steps: mixing a transition metal source, polysiloxane, a solvent, a curing agent and a platinum catalyst to obtain a mixed solution; the curing agent is vinyl modified siloxane; heating and curing the mixed solution to obtain a solid precursor; and crushing the solid precursor into powder, and then carrying out pressureless sintering in a protective atmosphere, thereby obtaining the product. According to the method, subsequent ball milling and other procedures are omitted, and impurity introduction to the product is avoided. According to the invention, the operation difficulty is greatly reduced, the production efficiency is improved, the energy consumption is reduced, and large-scale and low-cost production is realized.

The invention discloses metal ceramic MAX-phase composite powder for spraying and a preparation method of the metal ceramic MAX-phase composite powder, and belongs to the field of metal ceramic composite materials. The method comprises the following steps: mixing Ni powder, Cr powder and Cr2AlC nano powder with deionized water, a binder and a dispersant according to a specific ratio, and carrying out wet ball milling to prepare uniform slurry; carrying out spray granulation to obtain primary spherical powder; and finally, carrying out spheroidizing treatment on the primary powder by adopting radio frequency plasma under the protection of inert gas to obtain a final product. The core of the preparation method is that through an optimized two-step process, many limitations in the application aspect of an existing MAX phase material are solved, and the composite powder which is high in sphericity degree, good in flowability, compact in interior and stable in MAX phase component is successfully prepared. The powder can be directly used for thermal spraying, and an ideal raw material is provided for preparing a high-performance MAX-phase metal ceramic coating.

The invention provides an MAX phase / alumina layered composite ceramic and an in-situ synthesis preparation method thereof, and the method comprises the following steps: respectively preparing an alumina matrix layer and an MAX phase interface layer through a tape casting method, then alternately laminating the alumina matrix layer and the MAX phase interface layer, and finally carrying out hot pressed sintering to obtain a layered composite ceramic product. According to the invention, the layered composite ceramic which takes aluminum oxide as a matrix and MAX-phase ceramic as an interlayer is prepared through an in-situ synthesis technology, so that the effects of great toughening, strength increase without reduction and high damage tolerance are realized, and the fracture mode is converted from brittle fracture of aluminum oxide ceramic to safe stepped fracture. The strength and toughness of the aluminum oxide ceramic are successfully balanced and synergistically improved, and the industrial problem that strength and toughness cannot be both considered in a traditional aluminum oxide ceramic toughening technology is solved.

This invention discloses a coatable, moldable dual-functional coating material for heat protection and stealth, and its preparation method. The coating material is formed from a SiC-based composite ceramic aerogel slurry, a perovskite / MAX phase composite ceramic absorber, and a high-temperature resistant binder. The composite ceramic aerogel slurry is composed of SiC micro / nano-scale aerogel powder, SiC nanowires, and a high-temperature resistant binder; the perovskite ceramic absorber is lanthanum strontium manganese oxide (La). 1‑x Sr x MnO3), lanthanum strontium iron oxide (La) 1‑ x Sr x FeO3), lanthanum strontium cobalt oxide (La) 1‑x Sr x The MAX phase ceramic absorber is Ti3SiC2, and it contains substances such as CoO3. The technology of this invention enables the rapid application of coating materials to the surface of equipment via brushing, enhancing high-temperature radar absorption stealth and thermal protection capabilities, and facilitating the preparation and efficient repair of high-temperature stealth coatings.

In one general approach, a method for fabricating a MXene includes etching a MAX phase for selectively removing an A group element from the MAX phase, thereby forming a multilayer MXene. The multilayer MXene is then intercalated and exfoliated. In another general approach, a method for fabricating a MXene includes contacting a MAX phase with an acid and a fluorophosphate salt in a nonaqueous solvent for selectively removing an A group element from the MAX phase, thereby forming a multilayer MXene. The multilayer MXene is then intercalated and exfoliated.

The application discloses a high-temperature high-strength high-entropy MAX phase bulk material and a preparation method thereof. The high-temperature high-strength high-entropy MAX phase bulk material is expressed as M2AX, M is a combination of any four or more of Ti, Zr, V, Nb and Ta, the atomic percentage of each component in the M sublattice is between 5% and 35%, the sum of the atomic percentages of Zr and V is less than or equal to 16.7%, A is an Al element, and X is a C element. The bulk MAX phase material is prepared by a spark plasma sintering method. The high-temperature high-strength high-entropy MAX material prepared by the application has high purity and excellent mechanical properties at room temperature and high temperature, can be used for preparing high-temperature structural parts under special working conditions, and has a wide application prospect in the high-temperature field.

The invention belongs to the technical field of ceramic materials, and particularly relates to a wide-temperature-range MAX-phase ceramic material and a preparation method thereof. The chemical general formula of the ceramic material is (Ti1-x-yMnxMoy) 3AlC2, the value range of x is greater than or equal to 0.15 and less than or equal to 0.25, the value range of y is greater than or equal to 0.05 and less than or equal to 0.15, and the sum of x and y is 0.3. The preparation method comprises the following steps: weighing titanium powder, manganese powder, molybdenum powder, aluminum powder and graphite powder according to a stoichiometric ratio, and additionally adding 1-3at.% of excessive aluminum powder; and carrying out ball-milling mixing, drying and sieving, and sintering by adopting a two-stage hot pressing sintering process to prepare the MAX phase ceramic material. Through Mo and Mn element solution strengthening, excessive Al adding and two-stage gradient heating sintering processes, the structural stability, the mechanical property and the tribological property of the material in the wide temperature range from the room temperature to 1600 DEG C are remarkably improved.

This invention discloses a high-thickness, high-purity MAX phase coating and its preparation method. The method includes: 1. Mixing a metal oxide and a carbon source, followed by high-energy ball milling and spray granulation to prepare spherical precursor powder; 2. Depositing a transition layer on a sandblasted substrate surface using plasma spraying, and then depositing the spherical precursor powder on the transition layer to form a precursor coating; 3. Immersing the substrate with the precursor coating in molten salt for electrolysis, causing the precursor coating to be electro-deoxidized and converted into a MAX phase coating. This invention employs a synergistic process of "plasma spraying-molten salt electrochemical conversion," converting the sprayed precursor coating into a MAX phase coating through in-situ electro-deoxidation in molten salt electrochemistry. This process has high deposition efficiency and avoids the defects of carbon loss, phase decomposition, and oxidation in the coating product when directly thermally spraying MAX materials. It achieves the preparation of a high-thickness, high-purity MAX phase coating, suitable for the field of surface protection.

The invention belongs to the technical field of nuclear energy materials and surface engineering, and particularly relates to application of an MAX phase coating in a lead bismuth environment. The MAX phase coating is deposited on the surface of the structural material, so that the corrosion resistance and wear resistance of the steam generator can be remarkably improved. The result shows that under the conditions that the temperature is 450 DEG C, the normal load is 50N, the displacement amplitude is 75 microns, the vibration frequency is 25Hz and the cycle index is 106, a stable aluminum oxide oxidation layer and a compacted abrasive dust layer can be formed, so that the Ni element is effectively prevented from being dissolved, and the corrosion rate of a structural material is reduced; meanwhile, the abrasion depth of the structural material is reduced by 70% compared with that before protection, the structure is stable, the binding force is high, and the structural material is still kept complete and has no obvious peeling or failure phenomenon even in a long-cycle test.

The application discloses a method for growing a coating on an aluminum surface in situ, aluminum foil, an aluminum-based current collector, an electrode and a battery, wherein the method comprises: covering the surface of metal aluminum or an aluminum alloy with a MXene material, and then performing a heating treatment at a predetermined temperature; the functional groups of the MXene material contain one or more of F, Cl, Br or I. The method provided by the application can form a coating containing a MAX phase material on the surface of aluminum or an aluminum alloy in situ, the MAX phase material is a kind of ceramic, has the advantages of high conductivity and corrosion resistance, and the formed coating improves the corrosion resistance of the surface of aluminum or the aluminum alloy.

The invention discloses a material for an electromagnetic rail gun guide rail and a preparation method and application thereof, and belongs to the technical field of copper-based composite materials. The invention relates to a material for a guide rail of an electromagnetic rail gun. The material comprises a 5-20nm nano precipitated phase dispersed and distributed in a copper matrix; the MXene lamellas are continuously distributed on the grain boundary, and the nanometer MAX phase is distributed in the grain; and the nano precipitated phase, the MXene sheet layer and the nano MAX phase form a continuous reinforced network. The Cu-Ti-Be-Co alloy serves as a matrix, and unification of high strength and high conductivity is achieved through the synergistic effect of nanometer precipitated phase strengthening and MAX and MXene strengthening. The yield strength of the composite material reaches more than 700MPa and the conductivity is greater than or equal to 80% IACS (International Annealed Copper Standard) by regulating and controlling the interface combination of MAX and MXene with a matrix and the size and distribution of a nano precipitated phase, and the composite material is suitable for the fields of high-load electromagnetic guide rails, electromagnetic rail guns and the like.

The invention belongs to the technical field of two-dimensional nano materials, and relates to an MXene material as well as a preparation method and application thereof. The invention provides a novel and efficient MXene material preparation method which is characterized in that a precursor MAX phase material, a chalcogenide element simple substance and an iodine simple substance are mixed and then subjected to a high-temperature reaction in a vacuum environment. According to the method, a chalcogenide and iodine are ingeniously utilized to generate iodide (such as SeI2 or TeI2) with strong oxidizing property in situ at a high temperature, the chalcogenide in a high oxidation state can selectively oxidize A-site atoms (such as Al) in an MAX phase, the A-site atoms are converted into volatile iodide (such as AlI3) and escape from a system, and therefore selective stripping of an A layer is achieved; and a two-dimensional Mn + 1Xn skeleton is formed. Meanwhile, the reduced chalcogenide is directly bonded to the surface of MXene as a terminal group, and the functionalized MXene material with the chalcogenide terminal group (-S,-Se or-Te) is synthesized in one step.

The invention discloses a conductive reinforced phase material and an in-situ preparation method thereof, and belongs to the technical field of core electric contact materials for switches. The reinforced phase material is Ti3AlC2-coated Al2O3 and is composed of an inner layer and an outer layer in the coaxial direction, the inner layer is of a hollow cylindrical structure, the component of the inner layer is Ti3AlC2, and the outer layer is an Al2O3 coating layer generated on the surface of the inner layer in situ. The in-situ preparation method comprises the following steps: by taking a carbon nanotube as a template and eutectic molten salt as a carrier, preparing the conductive reinforced phase material with the double-layer concentric cylindrical composite structure through vacuum freeze drying, molten salt shielding reaction and high-temperature and high-pressure oxidation treatment. Compared with an original MAX-phase powder reinforced metal-based electric contact composite material and a commercial metal-based electric contact composite material, the novel material is compounded with conductive metal powder such as silver and copper, the electric conduction and heat conduction performance and the arc erosion resistance of the electric contact composite material can be remarkably enhanced, and the potential of replacing a traditional electric contact material is huge.

The application discloses a method for preparing MXene containing fluorine functional groups by a gas phase method and application, an electrode and a battery thereof, wherein the method uses sulfur hexafluoride gas as an etching agent, the sulfur hexafluoride gas reacts with a MAX phase material to etch the A component in the MAX phase material, and the MXene material is obtained; the MXene material has an accordion-like morphology or a two-dimensional sheet layer morphology; it is found that the SF6 gas can react with the MAX phase material by etching, and it is clear that the SF6 gas first reacts with the A component; based on the finding, by controlling the reaction conditions (time and temperature), the A component in the MAX phase material can be selectively etched, and then the MXene material is obtained, a new etching agent for preparing the MXene is provided, and the preparation technical route of the MXene is expanded. The SF6 gas etching is used to prepare the MXene, the gas is a colorless, odorless, non-toxic and non-combustible stable gas, has high safety, and is suitable for being used as a gas source for industrialized macro-preparation of the MXene material.

The application discloses a Ti3SiC2 MAX phase coating and a preparation method thereof. The preparation method comprises the following steps: depositing a Ti-Si transition layer on the surface of a substrate by using a high-power pulsed magnetron sputtering technology; introducing a carbon hydride; alternately depositing a Ti-Si coating and a Ti-Si-C coating, and the number of times of the alternately depositing is 2-8 times; and performing vacuum annealing treatment on the prepared coating to obtain the Ti3SiC2 MAX phase coating. The Ti-Si coating and the Ti-Si-C coating are alternately deposited by using the high-power pulsed magnetron sputtering technology, the deposited coating can be phase formed at a lower temperature in the subsequent heat treatment process, the generation of impurity phases can be reduced, and the purity of the MAX phase is improved.

The invention belongs to the field of nuclear materials, and particularly relates to a nuclear fuel and a preparation method thereof and a reactor, the nuclear fuel comprises a nitride matrix and an MAX phase material distributed in the nitride matrix; the chemical formula of the MAX phase material is Mn + 1AXn, M is selected from at least one of Ti and Cr, A is selected from at least one of Si and Al, X is selected from C, and n is 1 or 2. According to the nuclear fuel disclosed by the invention, the MAX phase material is introduced into the nitride matrix, and a corrosion-resistant oxide layer is generated in situ by utilizing the MAX phase material to block water permeation, so that the nuclear fuel has the properties of high thermal conductivity, relatively strong water corrosion resistance, steam oxidation resistance and radiation resistance, and can be applied to a light water reactor; the application risk of the existing uranium nitride fuel in the light-water reactor is reduced, and the safety and economy of the reactor are improved.

The invention discloses a high-thickness and high-purity MAX phase coating and a preparation method thereof.The method comprises the steps that firstly, metal oxide and a carbon source are mixed, and spherical precursor powder is prepared through spray granulation after high-energy ball milling; 2, depositing a transition layer on the surface of the substrate subjected to sand blasting treatment by adopting a plasma spraying method, and then depositing spherical precursor powder on the transition layer to form a precursor coating; and 3, immersing the substrate with the precursor coating into molten salt for electrolysis, so that the precursor coating is converted into the MAX phase coating through electric deoxidation. According to the method, a plasma spraying-fused salt electrochemical conversion synergistic process is adopted, the sprayed precursor coating is converted into the MAX phase coating through in-situ electrodeoxidation of fused salt electrochemistry, the deposition efficiency is high, the defects of carbon loss, phase decomposition, oxidation and the like of a coating product during direct thermal spraying of the MAX material are overcome, and the thermal spraying quality of the MAX material is improved. The preparation of the high-thickness and high-purity MAX phase coating is realized, and the method is suitable for the field of surface protection.

The invention discloses a high-entropy MXene / high-entropy MAX phase composite material and a preparation method thereof, and relates to functional composites.The preparation method comprises the following steps that mixed metal powder, metal gallium, conductive carbon black and mixed molten salt are put into a mortar to be fully ground for 4-13 min, and a first mixture is obtained; adding a proper amount of alcohol, and fully ball-milling for 10-24 hours to obtain a mixture II; and drying to obtain a mixture III. And transferring the mixture III into a high-temperature tubular furnace, and sintering to obtain the high-entropy powder. Pressing the high-entropy powder into a compact block I, carrying out secondary sintering treatment, polishing and grinding, and flattening the surface to obtain a compact block II; and embedding the compact block II in a fused salt etching agent, sintering, cleaning, and drying in vacuum to obtain the composite material. The prepared composite material has the advantages of being high in purity, good in reproducibility, reliable and controllable in technological process and the like, and has great application potential in the fields of frictional wear, electrochemistry, electromagnetic wave absorption and shielding and the like.

The invention relates to a new application of an MAX phase material in a fusion reactor cladding structural component, and the material has better Li-Pb lithium lead corrosion resistance compared with the existing material, is used for forming the fusion reactor cladding structural component, and prolongs the service life of the cladding structural component while meeting the requirements of a fusion experimental reactor and a demonstration reactor in the future.

The invention discloses a layered ceramic material coated silicon composite material, a preparation method thereof and an application of the material in a lithium ion battery cathode, and the preparation method comprises the following steps: grinding and mixing a few-layer MXene material, silicon powder and a lithium source solid-phase solvent, adding lithium powder, uniformly mixing, tabletting, heating and annealing under the protection of inert gas, and drying to obtain the layered ceramic material coated silicon composite material. And finally, cooling to room temperature, washing the obtained product to remove the lithium source solid-phase solvent and by-products, and then drying, thereby obtaining the layered ceramic material coated silicon composite material, wherein the layered ceramic material coated silicon composite material contains an interlaced MAX-phase 3D network structure in the layered ceramic material coated silicon composite material and the interlaced MAX-phase 3D network structure in the layered ceramic material coated silicon composite material. In the process of assembling a few layers of MXene materials, silicon and lithium are successfully packaged and coated in gaps of the three-dimensional network structure ceramic material at the same time, so that the cycling stability is improved, and the interface impedance of the surface of an electrode is reduced.

The application discloses a Cr-Ti-V-based out-of-plane ordered MAX phase ceramic material and application thereof. The ceramic material takes Cr2TiAlC2 as a matrix, is prepared by controlling a solid solution amount of V elements to partially replace Ti elements, and has a chemical formula of Cr2(Ti 1‑x V x )AlC2; wherein 0

The invention belongs to the technical field of ternary transition metal carbide materials, and particularly relates to a semiconductor type layered ternary transition metal carbide and a preparation method and application thereof. The chemical formula of the ternary transition metal carbide is M2SC, wherein the transition metal M is Y or Sc; the ternary transition metal carbide has an Rm type crystal structure. Comprising the following steps: by taking scandium powder or yttrium powder, sublimed sulfur and graphite powder as raw materials, sintering twice to obtain the semiconductor type layered ternary transition metal carbide. The MAX phase with semiconductor properties is obtained based on different valence states of sulfur for accurately adjusting the property of the MAX phase, the chemical formula of the semiconductor type ternary transition metal carbide is Y2SC and Sc2SC, the semiconductor type ternary transition metal carbide has an Rm type crystal structure, the existing MAX phase system is expanded by the material, and the application of the MAX phase material in the field of functional materials such as energy conversion and electronic materials is greatly expanded.

The invention discloses a medium-entropy carbide ceramic material with a textured lamellar structure and a preparation method and application of the medium-entropy carbide ceramic material, the chemical formula of a matrix of the medium-entropy carbide ceramic material is MC, M is Ti, Ta and Nb, the molar ratio of Ti to Ta to Nb is 2: 2: 1, and the grain morphology of the medium-entropy carbide ceramic material is in a directionally arranged lamellar shape. A single-step in-situ hot pressing method is adopted to prepare the entropy carbide ceramic in the textured structure, and in addition, in order to further improve the texture degree, a two-step hot pressing sintering method is provided and comprises the following steps: (1) performing hot pressing synthesis on an MAX phase containing a target M-site element; and (2) cutting the size of the MAX phase, and then carrying out secondary hot pressed sintering on the MAX phase. According to the method, the toughness of the base material is effectively and synergistically improved through texturing design, a new path is provided for opening up new structural ceramics, and a theoretical basis is provided for widening the application of the medium / high-entropy ceramic material in extremely complex working conditions.

The application discloses a kind of multilayer hetero-encapsulated tube based on MAX phase interface and preparation method thereof, belong to nuclear fuel cladding material technical field.The cladding tube sequentially includes from inside to outside: refractory metal lining pipe, first transition layer, second transition layer and SiC / SiC composite material outer layer.The first transition layer is the composite material layer with Ti3SiC2MAX phase as matrix and SiC nanoparticles and SiC whisker as reinforcing phase;The second transition layer is SiC nanowire layer.Preparation method includes: first transition layer is formed by pulling method outside refractory metal pipe, second transition layer is formed by electrophoretic deposition method, then SiC fiber preform is woven and deposited pyrolytic carbon interface, then vacuum impregnation is carried out in SiC whisker-containing polycarbosilane solution, finally, SiC matrix is deposited by chemical vapor infiltration.The application realizes excellent thermal-mechanical performance matching between heterogeneous materials by designing two layers of transition interface with function synergy, while ensuring the high gas tightness of cladding tube.

The application discloses a high-entropy MAX phase material and a high-entropy MXene material, and a preparation method and application thereof. The chemical formula of the high-entropy MAX phase material is M'2M''2AX3 or M'2M''AX2, wherein M' represents at least one of chromium, molybdenum or tungsten elements, M'' is selected from at least five elements from the group of IIIB, IVB, VB and VIB elements, A is selected from at least one element from the group of IIIA, IVA, VA and VIA elements, and X is a carbon element. The high-entropy MAX phase material belongs to a new type of material, has a layered structure and a multi-component atom composition with out-of-plane order; a new high-entropy MXene material can be obtained after etching the A component, and due to the existence of a plurality of component atoms, the material can be endowed with new properties, and has electromagnetic, optical, acoustic and other macroscopic physical characteristics that traditional materials do not have, and has application prospects in the fields of anticorrosion coating, high-temperature coating and the like.

This invention discloses a Ti-Nb-Zr multi-principal-element MAX phase ceramic material, its preparation method, and its application. 0.5 x Nb 0.5 x Zr 2x )2AlC2, where x The concentration is 0.05–0.15. This invention utilizes Zr to equimolarly replace Ti and Nb, dissolving Zr into multi-principal MAX phase ceramic materials. The amount of Zr added is limited to a specific range. The introduction of Zr, with its low electronegativity, not only preserves the original crystal structure of the MAX phase ceramic with almost no impact on its mechanical properties, but also promotes the formation of amorphous carbon at moderate temperatures, giving the material a low coefficient of friction and excellent lubrication performance at room temperature to 400 °C. Within the Zr addition range, the lubrication performance is greatly improved with increasing Zr addition.

The application discloses a preparation method of infrared and radar stealth fabric, comprising the following steps: S1, fabric is ultrasonically immersed, and is soaked by using an alkaline solution, is washed and dried, and a pretreated fabric is obtained; S2, wave-absorbing powder and coating glue are mixed, a thickening agent is added, and the mixture is coated on the fabric, and the fabric is dried, and a composite fabric is obtained; S3, a MAX phase material is etched, and an MXene dispersion liquid is obtained; S4, coating glue is coated on the composite fabric, the MXene dispersion liquid is coated, and the fabric is dried, and the coating is repeated 1-3 times, and an MXene / wave-absorbing powder / fabric is obtained. By using the wave-absorbing powder to form a radar stealth layer, and by coating polyurethane coating glue and then coating MXene, the stability and continuity of the MXene film are ensured, the emissivity is reduced, and infrared stealth is realized, that is, the integrity of the MXene structure is not damaged by traditional mixed coating, and by accurately controlling the amount of MXene, the infrared low emissivity and radar wave absorption performance are balanced, and high-performance infrared and radar dual-band stealth is realized.

The application discloses a kind of MXene nanometer roll, composite material and its preparation method and use, wherein, the MXene nanometer roll is a kind of MXene material with one-dimensional hollow roll structure, by two-dimensional MXene material curling self-assembly is obtained, break the cognition of people to MXene material belongs to two-dimensional material.The application further provides the preparation method of MXene nanometer roll, steps include: two-dimensional MXene material or etching MAX phase material is obtained accordion appearance etching material, dispersed in liquid phase containing positive ion pair reagent, under the action of external force, obtain MXene nanometer roll, preparation method is simple and easy to operate.The MXene nanometer roll of the application and carbon nanotube all have one-dimensional nanostructure, can be used as alternative material to replace carbon nanotube;Since the application also has the characteristics of distinguishing carbon nanotube, more new field applications can be realized, such as as slow-release material etc.