84results about How to "Rapid densification" patented technology

A green article comprising an A-B powder mixture and methods of manufacturing such green articles and corresponding sintered articles are disclosed. The A-B powder mixture consists of a minor volume fraction of a relatively fine powder A and a complementary major volume fraction of a relatively coarse prealloyed powder B wherein the A-B powder mean particle size ratio is at least about 1:5. Metal powder A consists of one or more elemental metals or alloys which has a melting or solidus temperature above the highest sintering temperature at which the A-B powder mixture may be sintered without slumping. Prealloyed metal powder B consists of one or more alloys which are amenable to supersolidus liquid phase sintering. Green articles made from the A-B powder have a wider sintering temperature window than do articles made from prealloyed metal powder B alone.

The invention designs a composite material. The composite material comprises carbon-fiber perform, matrix carbon, filler and diamond-like carbon, wherein the matrix carbon is uniformly adhered on the carbon fiber of the perform to form the carbon-fiber perform with the matrix carbon; the filler fills the inside of the carbon-fiber perform with the matrix carbon and coats the outside of the carbon-fiber perform with the matrix carbon to form a semifinished product; the diamond-like carbon comprises a diamond-like carbon layer coated on the semifinished product; and the filler contains a Ti element, a Si element, a C element and a Mo element. The composite material has the advantages that a method of combining four processes of CVI, SI, RMI and PECVD to prepare a finished product with the advantages of high compactness, low thermal expansion coefficient and friction coefficient, high self-lubricating property, high thermal conductivity, oxidation resistance, thermal shock resistance, ablation resistance, wear resistance, high strength and toughness and the like; and simultaneously, the process is simple, the preparation period is short, the equipment requirement is low, the cost is low, net shaping can be realized and convenience is brought for large-scale industrial application.

The invention relates to a dynamic pressure electric pulse double-field control sintering furnace and a sintering method. The sintering furnace comprises a furnace body, a dynamic pressure system, a pulse current generator and a sintering controller. The furnace body is connected with the dynamic pressure system and the pulse current generator. The dynamic pressure system and the pulse current generator are both connected to the sintering controller. A die is arranged in the furnace body. The dynamic pressure system comprises an upper press head electrode, a lower press head electrode, an upper press head, a lower press head, a constant pressure control module, a dynamic pressure control module and a pressure master control module. The dynamic pressure system is connected with the sintering controller. The pulse current generator is connected with the upper press head electrode and the lower press head electrode and connected with the sintering controller as well. The sintering controller controls the dynamic pressure system and the pulse current generator to generate the adjustable dynamic pressure for a material to be sintered and conduct plasma pulse current sintering on the material to be sintered. The dynamic pressure electric pulse double-field control sintering furnace and the sintering method can be widely applied to sintering of the high-performance material.

The invention relates to aluminum-lithium alloy, in particular to a method for manufacturing a three-dimensional large-size aluminum-lithium alloy round ingot through spray forming. Ar atomization is adopted, spray forming is carried out on aluminum-lithium alloy melt which is subjected to gas removing, slag removing, refining and filtering, and a cylindrical ingot blank is formed; through optimization combination of adjustment of the spraying angle, atomization air pressure, the melt superheating temperature, the receiving disc descending speed and the rotating speed, rapid, precise and compact forming of the aluminum-lithium alloy melt is achieved, and the forming rate is not lower than 10 kg/min; the obtained ingot blank is regular in shape, high in compactness and free of chemical component macrosegregation, and the diameter of the ingot blank can reach phi 650 mm; the yield of the large-size aluminum-lithium alloy ingot blank produced through the method is more than 80%.

The invention discloses a preparation method of a graphene enhanced FCC-type high-entropy alloy. The method comprises the steps that 1, FCC-type high-entropy alloy powder is prepared by a gas atomization method; 2, the FCC-type high-entropy alloy powder is subjected to ball milling and then dried; 3, the dried FCC-type high-entropy alloy powder is mixed with graphene nanoflakes, then composite powder is obtained by ball milling; and 4, the composite powder is subjected to spark plasma sintering, and the graphene enhanced FCC-type high-entropy alloy is obtained after cooled in a furnace. According to the preparation method, short-time high-energy ball milling is adopted, so that the FCC-type high-entropy alloy powder forms multi-scale lamellar structures and produces fine nanocrystals, combined with low-energy ball milling, the graphene nanoflakes are completely and evenly dispersed between the lamellar structures, the graphene enhanced FCC-type high-entropy alloy with multi-scale crystals is prepared, the strengthening effect is effectively enhanced, and the good matching of strength and plasticity is achieved.

The invention provides a preparation method of transparent magnesia-alumina spinel ceramic MgO.nAl2O3, wherein n is larger than or equal to 1 and smaller than or equal to 2. The method specifically comprises the steps as follows: 1) MgO powder and alpha-Al2O3 are mixed and ball-milled, a solvent is removed, sieving is performed, and magnesia-alumina spinel powder is obtained after a high-temperature solid-phase reaction and sieving; 2) the magnesia-alumina spinel powder is placed in a graphite mold, the graphite mold is placed in spark plasma sintering equipment for forming and pre-sintering,and a pre-sintered body is obtained; 3) the pre-sintered body is placed in a muffle furnace to be sintered again, natural cooling is performed, and a pore-closed sintered body is obtained; 4) the pore-closed sintered body is subjected to hot isostatic pressing sintering treatment, a sintered sample is polished, and the transparent magnesia-alumina spinel ceramic is obtained. By means of the method, the sample composition can be controlled, high compactness can be obtained without addition of a sintering aid, large-scale industrial production can be performed through sintering in non-pressure air, and the production cost can be reduced.

The invention provides a 3D printing method for a ceramic material. The 3D printing method comprises the following steps: A) distributing a material with high dielectric loss into the powder of a material with low dielectric loss so as to form a printing body; and B) placing the printing body obtained in the step A) in a microwave electromagnetic field for curing and sintering of the printing body. The 3D printing method provided by the invention is based on the characteristics of selective heating and integral heating of electromagnetic waves; when a supporting structure totally wraps the printing body, selective heating, curing and sintering of a printing area are realized, and structural uniformity is improved; meanwhile, outfield auxiliary effect can promote mass transfer process, so rapid densification of the ceramic material is realized; and a microstructure different from the microstructures of conventional sintering products can be obtained while the macrostructure of the shape of the ceramic material is designed, controllable manufacturing of organizational structures of different sizes can be realized, and thus, structure-function integrated designing and manufacturing of the ceramic material is realized. The 3D printing method has the characteristics of simple raw material treatment and low printing cost and has the potential of industrial application.

The invention discloses a preparation method of a SiCf/SiC composite material with a SiC coating layer. The preparation method comprises the following steps: S1, weaving SiC fiber into a SiC fiber weaving piece; S2, depositing a pyrolytic carbon interface coating layer on the surface of the SiC fiber of the SiC fiber weaving piece, thus obtaining a SiC fiber weaving piece with the interface coating layer; S3, carrying out densification treatment on the SiC fiber weaving piece with the interface coating layer through a precursor infiltration and pyrolysis technology, thus obtaining the SiCf/SiCcomposite material, wherein the temperature during pyrolysis is 1400 to 1800 DEG C; S4, depositing the SiC coating layer on the surface of the SiCf/SiC composite material through a CVD (Chemical Vapor Deposition) technology, thus obtaining a hydrothermal corrosion-resistant SiCf/SiC composite material with the SiC coating layer. The SiCf/SiC composite material with the SiC coating layer, preparedby the preparation method disclosed by the invention has hydrothermal corrosion resistance.

The invention relates to a rapid preparation method of a high-temperature-resistant structured wave-absorbing ceramic matrix composite material. The SI+RMI process is adopted to prepare a SiC fiber-reinforced silicon-based ceramic matrix composite material. Firstly, Si3N4 powder, BN powder, SiC powder, or C + Si3N4 mixed powder is respectively introduced into a SiC fiber preform through the SI process; and then, through the RMI process, a silicon melt is infiltrated into the composite material to be combined with or react with the above powder respectively so as to generate a Si3N4-Si matrix,a Si-B-N matrix, a SiC-Si matrix or a Si-C-N matrix, and an electromagnetic impedance matching type matrix (such as Si3N4-Si, Si-B-N, etc.) or an electromagnetic wave-absorbing type matrix (such as SiC-Si, Si-C-N, etc.) which meets the requirements of the structure wave-absorbing ceramic matrix composite material is prepared. Rapid densification of the composite material is realized, preparation cycle of the composite material is effectively shortened, and density and mechanical/wave-absorbing properties of the composite material are improved.

The present invention provides chimeric receptors that include an extracellular domain from a metabotropic glutamate receptor and a non-native signal peptide, e.g., a calcium receptor signal peptide. The invention also includes methods of preparing such chimeric receptors, and methods of using such receptors to identify and characterize compounds which modulate the activity of metabotropic glutamate receptors. The invention also relates to compounds and methods for modulating metabotropic glutamate receptor activity and binding to metabotropic glutamate receptors. Modulation of metabotropic glutamate receptor activity can be used for different purposes such as treating neurological disorders and diseases, inducing an analgesic effect, cognition enhancement, and inducing a muscle-relaxant effect.

Biodegradable, magnesium alloys and composites, articles produced therefrom, methods of making the same, and methods of using the same are described.

The invention relates to a method for fast preparing a translucent Li-alpha-SiAlON ceramic material, comprising the following steps of: selecting and mixing materials of alpha-Si3N4, AlN, alpha-Al2O3 and Li2CO3 according to a general formula of LimSil2-m-nAlm+nOnN16-n, wherein m is larger than 0.4 and less than 2.0, and n is larger than 0.8 and less than 2.0; carrying out ball milling and drying, grinding and screening with a 200-mesh sieve; putting the processed mixture in a discharge plasma sintering furnace at the sintering pressure not less than 20MPa and under the protection of N2 gas, raising the temperature to 950-1050 DEG C, preserving the temperature for 1-3 minutes, then raising the temperature to 1600-1850 DEG C for sintering for 0-20 minutes, and cooling along with the furnace; cutting, grinding and polishing till a mirror surface is formed. The discharge plasma sintering method has simple process, fast temperature raising, low sintering temperature, short time and low energy consumption. The prepared translucent Li-alfa-SiAlON ceramic material has excellent infrared transparency.

The invention relates to the technical field of ceramic materials, and provides a high-strength aluminum nitride ceramic substrate and a preparation method thereof. The high-strength aluminum nitride ceramic substrate comprises the following raw materials by weight: 78-85 parts of modified aluminum nitride powder, 36-42 parts of a solvent, 1.2-2 parts of a dispersant, 8-11 parts of a binder and 2-4 parts of a plasticizer; and the aluminum nitride ceramic substrate is prepared through the procedures of ball milling, vacuum foaming, tape casting, isostatic pressing, rubber discharging, primary sintering and secondary sintering in sequence. The thermal conductivity of the prepared aluminum nitride ceramic is 180 W/(m.K) or above, the bending strength is 520 MPa or above, and the problem that the bending strength of the aluminum nitride ceramic is not high in the prior art is solved.

The invention relates to a thermoelectric material Mg2Sn and a preparation method thereof, belonging to the technical field of inorganic materials. The invention is characterized in a high-thermoelectric-property thermoelectric material prepared at low temperature and a preparation method thereof. The method comprises the following steps: mixing powdery MgH2, Sn and Y in a mol ratio of 1.9:1:0.1, putting in a sealed teflon ball milling tank, and carrying out ball milling in a high-speed vibrating ball mill for 20-40 minutes to obtain a powdery MgH2-Sn-Y uniform mixture; and sealing the powdery uniform mixture in a ceramic pipe, putting the sealed powdery mixture in a pipe furnace, and reacting at 573-673 K to obtain the powdery thermoelectric material Mg2Sn.

The invention discloses a method for preparing a hot pressed sintered high-density magnesium oxide target and mainly solves the technical problems of easiness in transformation, low rate of finished products, higher cost and low purity of the target in the prior art. The method comprises the following steps of: a, weighing nano-sized magnesia powder with a certain amount and high purity, and selecting a mould which has the same diameter as the target prepared according to the requirement; b, placing the mould into a hot-pressing sintering furnace body, charging by a vibration funnel method, measuring and ensuring that the stack heights of the powders in the mould are the same; and c, vacuumizing, heating and pressurizing, and maintaining pressure until the sintered size of the magnesium oxide target is a design value. The method has a simple preparation process and can quickly enable the product to be densified; the prepared product has the advantages of high density, fine grain and the like; other impurities cannot be introduced; the product is difficult to deform and crack during sintering; the rate of finished products is high; and the high-density high-purity magnesium oxide target can be prepared by the method.

The invention belongs to the technical field of combustion synthesis, and particularly relates to a method for preparing molybdenum copper alloy by combustion synthesis in a high gravity field. The method of the invention adopts Al-CuO as a reaction system, and adopts Cu, Mo, and B2O3 as diluents. High temperature thermite reaction between various raw materials is induced in a high gravity field (500-5000g); rapid separation, densification, and cooling of the products of ceramic melt and metal melt of the thermite reaction in the high gravity field is realized to obtain a ceramic solid and a metal solid; and the pure copper layer at one end of the metal solid is cut to obtain the molybdenum copper alloy. The method of the invention has the characteristics of simple process, short preparation period, low cost, and the like.

The invention discloses a preparation method of low-modulus and high-toughness silver-containing titanium alloy. The preparation method comprises the following steps: 1, carrying out low-energy ball-milling mixing on titanium alloy powder and nano silver powder to obtain mixed powder, wherein the titanium alloy powder is in the micrometer scale and the nominal composition of the titanium alloy powder is Ti-3Zr-2Sn-3Mo-25Nb; 2, sintering the mixed powder to form silver-containing titanium-based sintering blanks; and 3, carrying out hot-rolling treatment on the silver-containing titanium-based sintering blanks to obtain silver-containing titanium alloy profile. According to the preparation method, low-energy ball-milling mixing is adopted to uniformly disperse nano silver powder on the surface of titanium alloy powder, so that during the sintering process, nano silver powder is uniformly diffused and solid-solution of nano silver powder is carried out on titanium alloy matrix, segregation of the Ag element is effectively avoided, dispersing uniformity of Ag in silver-containing titanium alloy profile is improved, the plasticity is not damaged while ensuring that the strength of the silver-containing titanium alloy profile is improved, and the low elasticity modulus characteristic is kept.

Embodiments can relate to an improved hydroflux, additive or electroless plating assisted densification cold sintering process to densify powdered metals at lower compaction pressures and lower temperatures (e.g., 520 MPa and 140° C.). The process can involve inducing dissolution precipitation mechanisms at powder interfaces by introducing a transport phase (formed by the introduction of water during the process to suppress melting temperatures) that is not an aqueous solution. Particle interfaces in the cold sinter fuse together by the presence of the additional transport phase, thereby reducing the temperatures and pressures needed for compaction. Some embodiments involve the use of elements to form a eutectic at the desired low temperature, thereby stabilizing certain crystal structure shapes of isometric crystal systems, inducing rapid densification, and facilitating pore smoothing. Embodiments of the process can be used to generate a green compact via sintering that exhibits improved green strength.