774 results about "Vacuum sintering" patented technology

The invention discloses a low-cost high-cerium neodymium iron boron diffusion magnet and a preparation method and application thereof, and relates to the technical field of rare earth permanent magnet materials. Comprising the steps that a neodymium iron boron alloy casting piece Ce30 with the Ce content being 10 wt% and a neodymium iron boron alloy casting piece Ce50 with the Ce content being 15 wt% are prepared through burdening and smelting, after the Ce30 and Ce50 neodymium iron boron alloy casting pieces are evenly mixed, hydrogen decrepitation, jet milling, oriented pressing, cold isostatic pressing and vacuum sintering are sequentially carried out, and a high-cerium sintered neodymium iron boron matrix is obtained; carrying out grain boundary diffusion on the high-cerium sintered neodymium-iron-boron matrix to obtain a high-cerium neodymium-iron-boron diffused magnet; the performance of the blank prepared through the method is close to the N40 mark, the performance of the magnetic sheet after diffusion reaches the 38MT mark, the magnetic performance is kept at the high level, the Ce content is high, efficient utilization of the high-abundance element cerium is achieved, the production cost of the rare earth permanent magnet material is greatly reduced, industrial batch production can be achieved, and balanced utilization of rare earth resources is promoted.

The invention relates to the field of aluminum materials, and provides an automobile corrosion-resistant aluminum material and a preparation method thereof.The automobile corrosion-resistant aluminum material is prepared from cerium oxide loaded aluminum oxide nanorods, scandium / boron nitride nanotubes, zirconium powder, magnesium powder, copper powder, manganese powder, silicon carbide nanoparticles, TiB2 nanoparticles, aluminum powder and stearic acid. Wherein the cerium oxide loaded aluminum oxide nanorod is composed of an aluminum oxide nanorod and cerium oxide nanoparticles loaded on the surface of the aluminum oxide nanorod, and the scandium / boron nitride nanotube is composed of a boron nitride nanotube and a scandium nanolayer uniformly coated on the surface of the boron nitride nanotube. The material is prepared through mechanical ball milling, cold isostatic pressing forming, vacuum sintering and aging treatment, and finally the aluminum-based composite material containing the Al3Sc nano precipitated phase and the boron nitride nanotube reinforced phase is formed. And an Al3Sc precipitated phase and an aluminum matrix form a coherent interface, so that the strength, the corrosion resistance and the wear resistance of the material are improved. Through nanostructure optimization, high performance of the aluminum alloy is achieved, and the aluminum alloy is suitable for the fields of automobiles, aerospace and the like.

The invention discloses a tungsten alloy material containing a silicon carbide reinforced Al2O3-SiO2-based multiphase ceramic coating and a preparation method of the tungsten alloy material, and belongs to the field of ceramic material preparation. The method comprises the following steps: ball-milling and mixing powder raw materials containing modified silicon carbide, aluminum oxide, silicon dioxide and lead oxide with a solvent, and defoaming to obtain ceramic slurry; the ceramic slurry is brushed on the surface of a tungsten alloy matrix subjected to surface pretreatment, and after drying, vacuum sintering is performed to obtain the tungsten alloy. The compact silicon carbide reinforced Al2O3-SiO2-based multiphase ceramic coating is introduced to the surface of a tungsten alloy matrix, the hardness, the high-temperature oxidation resistance and the high-temperature carburization resistance of a tungsten alloy material are remarkably improved, the stability of the coating can be improved through the silicon carbide distributed in a dispersed point shape, the thermal expansion coefficient of the coating is evenly reduced, and the hardness, the high-temperature oxidation resistance and the high-temperature carburization resistance of the tungsten alloy material are improved. The thermal expansion coefficient difference value between the multiphase ceramic coating and a tungsten alloy matrix is reduced, and the thermal shock resistance of the coating is improved.

The invention discloses a method for realizing pure pore size regulation and control of a silicon carbide ceramic membrane, which comprises the following steps of: a) adding silicon carbide, sodium carboxymethyl cellulose and a dispersing agent into water, and uniformly ball-milling to obtain spraying slurry; and b) spraying the spraying slurry to the surface of a silicon carbide ceramic membrane to be regulated and controlled, naturally airing, carrying out vacuum drying at 75-85 DEG C for 2-5 hours, putting into a high-temperature furnace, carrying out vacuum sintering at 800-1200 DEG C for 1-3 hours, putting into a muffle furnace, and carrying out oxidation sintering at 700-900 DEG C for 25-45 minutes. According to the method, the pore size of the silicon carbide ceramic membrane can be subjected to pure regulation and control, operation is easy, cost is low, large-scale production is easy to achieve, the influence on the thickness of an original membrane is small, the membrane layer firmness is good, the filter flux of pure water is still high, and the application value of the silicon carbide ceramic membrane in water treatment is remarkably improved.

The invention relates to a preparation method of bubble-free low-expansion quartz glass, and belongs to the technical field of quartz glass preparation and production. A high-density quartz green body is obtained through a mold pressing and cold isostatic pressing secondary forming process, the contact tightness of quartz glass powder particles is guaranteed, the quartz glass prepared after three-stage heating vacuum sintering is free of bubbles, the defect that low-expansion quartz glass prepared through a traditional method is prone to generating bubbles is overcome, and the quality of the quartz glass is improved. The mechanical and optical properties are not good; meanwhile, the high-quality quartz glass product is prepared by taking waste materials, tailings and waste materials generated in the production of the low-expansion quartz glass by the existing CVD method as raw materials, so that waste utilization is realized; and the method has positive significance on enterprise development.

The invention discloses a preparation method of a high-temperature excitation coil based on an AMB process, and relates to the technical field of magnetic levitation, and the preparation method specifically comprises the following steps: S1, silicon nitride ceramic is perforated; s2, through hole filling and surface screen printing; s3, carrying out vacuum sintering on the metal foil and the silicon nitride ceramic; s4, performing coil patterning and surface treatment; s5, preparing a single-layer silicon nitride ceramic metal coil; s6, preparing a ceramic isolation sheet; s7, performing lamination and vacuum sintering; the magnet exciting coil prepared by the invention has relatively good reliability and long service life in a service environment of 550-600 DEG C.

The invention discloses a vacuum high-wear-resistance zirconia-based composite ceramic material as well as a preparation method and application thereof, and belongs to the technical field of ceramic material preparation. The preparation method comprises the following steps: 1) sufficiently and uniformly mixing zirconium oxide powder, a stabilizer and absolute ethyl alcohol to prepare mixed slurry; 2) adding whiskers into the mixed slurry, fully and uniformly stirring, and then drying and sieving to obtain mixed powder; 3) carrying out static pressure molding on the mixed powder to prepare a composite ceramic biscuit, and then carrying out vacuum sintering and annealing treatment to prepare composite ceramic; and 4) performing high-temperature carburizing treatment on the composite ceramic to obtain carburized composite ceramic, and performing surface treatment to obtain the vacuum high-wear-resistance zirconia-based composite ceramic material. The vacuum wear rate of the zirconia-based composite ceramic material provided by the invention is reduced by 1-2 orders of magnitude compared with that of a traditional yttria-stabilized zirconia material, and a novel high-wear-resistance ceramic material is provided for precise friction driving parts in the field of aerospace.

The invention relates to the technical field of composite resin preparation, and discloses a silicon-molybdenum alloy target material preparation method which comprises the following steps: preparing raw materials, selecting molybdenum powder and silicon powder with the purity not lower than 99.9%, mixing, putting the raw materials into a vacuum mixer, vacuumizing to 0.01-0.1 Pa, stirring for 1-5 hours, carrying out ultrasonic assistance, controlling the temperature to 25-40 DEG C to prevent oxidation, and carrying out a forming process. Filling the mixed powder into a detachable hard alloy mold coated with a 0.05-0.2 mm boron nitride coating, carrying out cold press molding, maintaining the pressure for 5-20 minutes to obtain a biscuit, sintering, putting the biscuit into a vacuum sintering furnace, firstly carrying out microwave-assisted heating, then raising the temperature to 1500-1800 DEG C, introducing trace argon in the later period to regulate and control a structure, carrying out a post-treatment process, carrying out numerical control processing on a sintered target material, carrying out chemical cleaning on the mixed solution of hydrofluoric acid and nitric acid, and finally carrying out vacuum sintering. Performing plasma treatment; and finally, performing vacuum packaging and filling high-purity nitrogen. The raw materials are high in purity and excellent in granularity; uniformly mixing and preventing oxidation; forming and sintering are precisely controlled, and the quality of the target material is guaranteed; the surface performance is improved through post-treatment, packaging is oxygen-proof and moisture-proof, and the target material meets the high-end industry requirement.

The invention relates to the technical field of solid waste recycling and functional building materials, in particular to a wave-absorbing wall material based on a waste glass fiber wind power blade and a preparation method of the wave-absorbing wall material. The wave-absorbing wall material based on the waste glass fiber wind power blade is mainly prepared from the following raw materials in parts by mass: 60-68 parts of waste glass fiber wind power blade granules, 30-35 parts of silicon-aluminum solid wastes, 2-5 parts of a wave-absorbing reinforcing agent and 6-10 parts of water. According to the invention, waste wind power blades and silicon-aluminum solid wastes are used as raw materials, a high-strength porous carbon skeleton structure is formed in the material through a vacuum pugging molding and vacuum sintering process, and meanwhile, a ferrite wave-absorbing reinforcing agent is mixed to form a composite wave-absorbing electromagnetic structure of a carbon aggregate-dielectric loss material and a ferrite particle-magnetic loss material; collaborative optimization of the electromagnetic wave absorption performance and the material mechanical property is achieved, and good ecological value and economic benefits are achieved.

The invention provides a temperature damage detection method based on an optimized vacuum sintering furnace and a temperature measuring device, and belongs to the related field of heat transfer science, and the method comprises the following steps: optimizing a vacuum sintering furnace structure by adopting different thermal insulation structures, and deducing a one-dimensional performance simulation model of a carbon felt thermal insulation layer; according to the one-dimensional performance simulation model of the carbon felt thermal insulation layer, the temperature rise curve and the workpiece temperature, the value range of the thickness of the carbon felt thermal insulation layer at different sintering temperatures is calculated by utilizing a reverse simulation principle, and then the optimal thickness of the carbon felt thermal insulation layer is obtained in the value range of the thickness of the carbon felt thermal insulation layer at different sintering temperatures by utilizing forward simulation; and the optimal thickness of the carbon felt heat preservation layer is adopted as the length of the temperature measuring device, the temperature measuring device of the vacuum sintering furnace is constructed, the temperature of the vacuum sintering furnace is measured through the multiple temperature measuring devices, and a temperature damage detection result is obtained according to the measurement result. According to the method, the problem that the temperature in the effective heating area after structure optimization cannot be directly measured due to too high temperature is solved.

The invention discloses a method for solid-phase regeneration of a high-homogeneity intermediate alloy from dissimilar metal chips. The method comprises the following steps that firstly, metal elementary substance chips and intermediate alloy chips are subjected to ultrasonic cleaning and drying; step 2, mixing; step 3, crushing processing; step 4, pressing; 5, pulse current assisted vacuum sintering is carried out under the pressurization condition; step 6, performing hot extrusion deformation; step 7, carrying out homogenization treatment; 8, surface oxide skin is removed; and ninthly, machining is conducted, and the granular or scrap-shaped high-homogeneity intermediate alloy is obtained. According to the method, the cost of raw materials for preparing the intermediate alloy is reduced through solid-phase recycling of the metal filing, after the metal filing is crushed and pressed, pulse current is used for assisting vacuum sintering and hot extrusion deformation, local heating and rapid pre-compounding of the filing interface are achieved, an oxidation film is crushed, and the mechanical occlusal force of the filing interface is improved; and the defect healing capacity is improved through the homogenization treatment process, and the solid-phase regenerated high-homogenization intermediate alloy with uniform components is obtained.

The invention relates to a rare earth modified medium-entropy alloy with a low reaction threshold value, which is characterized in that the rare earth modified medium-entropy alloy with the low reaction threshold value is a TiZrTa medium-entropy alloy, and the adopted rare earth is an element Ce. The invention further discloses a preparation method of the rare earth modified medium-entropy alloy. By adopting vacuum sintering and vacuum high-frequency induction melting, the obtained alloy has high strength, good plasticity, excellent energy release characteristic and lower reaction threshold, and has potential application value in energetic structure materials.

The invention relates to the technical field of optical coating materials, and particularly discloses a trititanium pentoxide optical coating material and a preparation process thereof. The invention relates to a preparation process of a trititanium pentoxide optical coating material, which comprises the following specific steps: mixing titanium dioxide and titanium powder by using a dry method, then carrying out hydraulic pressure, then carrying out vacuum sintering, cooling, then taking out trititanium pentoxide sintered crystals, then carrying out surface modification on the trititanium pentoxide sintered crystals and a titanate coupling agent, and finally carrying out vacuum sintering to obtain the trititanium pentoxide optical coating material. Drying and crushing to obtain a trititanium pentoxide finished product; and mixing the trititanium pentoxide finished product with silicon dioxide and aluminum oxide, and sintering to form the trititanium pentoxide optical coating material. Under the synergistic effect of all processes and raw materials, prepared trititanium pentoxide finished product particles are promoted to form a more compact sintered body, a uniform and stable interface is formed in the coating process, and the bonding strength and wear-resistant stability of the coating material are improved.

The present invention discloses a method for optimizing a silicon carbide vacuum sintering furnace based on computational heat transfer simulation, comprising the following steps: establishing a heat radiation and heat conduction model of the vacuum sintering furnace during the heating process according to the parameters of the vacuum sintering furnace body; performing computational heat transfer simulation to obtain a temperature rise curve of the vacuum sintering furnace during the entire heating process; optimizing the original furnace type by calculating and comparing the temperature rise curves of workpieces under different heating rates, different graphite heating tube diameters, and different graphite heating tube-to-effective heating zone spacings, the temperature difference between the vertex workpiece and the center workpiece, and the temperature difference between the surface and the core of the same workpiece. The present invention provides a reference for the performance optimization of the vacuum sintering furnace by studying the effects of different heating rates, different graphite heating tube diameters, and different graphite heating tube-to-effective heating zone spacings on the heating efficiency and furnace temperature uniformity of the vacuum sintering furnace, meets the process production requirements of the silicon carbide vacuum sintering furnace, and improves the heating efficiency and furnace temperature uniformity of the heating system.

The invention relates to the technical field of silicon carbide boat support manufacturing, and particularly discloses a silicon carbide boat support and a manufacturing method thereof.The manufacturing method comprises the following steps that S1, the boat support is designed through three-dimensional modeling software; s2, uniformly mixing the silicon carbide powder with various particle sizes; s3, slurry preparation: stirring and mixing the powder and a curing agent to obtain slurry; s4, the three-dimensional model slices of the boat support are printed and formed through a 3D printing device, and glue is smeared between every two layers of slices; s5, performing hot air drying on the blank in a drying oven; s6, in a vacuum sintering furnace, the blank is subjected to vacuum sintering and glue discharging; s7, the blank is subjected to polishing, machining, sand blasting, purification, ultrasonic cleaning and drying process treatment; compared with traditional injection molding, the silicon carbide boat support is manufactured through 3D printing, mold production and manufacturing can be omitted, and the production cost is reduced; and various forming parameters are visualized, so that the forming difficulty is reduced, and the yield of the silicon carbide boat support is improved.

The invention relates to the technical field of electrical material preparation, in particular to a preparation method of a graphene reinforced tungsten-copper composite material. Comprising the following steps that 40-50 parts by volume of graphene powder and 50-60 parts by volume of copper powder are weighed, stirred and mixed, and premixed graphene copper composite powder is obtained; 25-35 parts by volume of the premixed graphene copper composite powder and 2-4 parts by volume of absolute ethyl alcohol are weighed, mixed and ball-milled, then isostatic pressing forming, vacuum sintering, machining and powdering are conducted, and graphene copper composite powder is obtained; 60-80 parts by mass of tungsten powder, 32-36 parts by mass of copper powder, 4-8 parts by mass of graphene copper composite powder and 5-8 parts by mass of paraffin are weighed, mixed ball milling, cold press molding, vacuum sintering, re-pressing and re-sintering and cooling are conducted, and the graphene reinforced tungsten copper composite material is obtained. According to the preparation method disclosed by the invention, the graphene tungsten copper composite material with excellent mechanical property and electrical property is obtained by combining the graphene copper composite powder with a re-pressing and re-sintering process.

The invention provides a semiconductor grade silicon dioxide vacuum sintering furnace which comprises a furnace body, a heating cavity is formed in the middle of the furnace body, and a rear door body is arranged at the first end of the furnace body; the material dragging trolley is arranged in the furnace body in a sliding mode, and a workpiece is placed on the material dragging trolley; the front door body is arranged on one side of the material dragging trolley, and when the material dragging trolley slides into the heating cavity, the front door body seals the second end of the furnace body; the device has the beneficial effects that through the arrangement of the pressing and rotating assembly, a workpiece on the material dragging trolley can be fixed from the two ends, it is ensured that the workpiece is always kept stable in the heating process, and the workpiece can be driven to rotate by the pressing and rotating assembly. In the heating process, the workpieces can be heated more uniformly through rotation of the workpieces, the heating effect and the product quality are improved, the workpieces can be automatically assembled and disassembled through arrangement of the material dragging trolley, the labor intensity of workers is reduced, and the working efficiency is improved.

The invention discloses a SiC power module sintering packaging method, and relates to the technical field of power module packaging, and the method comprises the steps: sequentially carrying out the ultrasonic cleaning, plasma activation and drying of a SiC chip and a ceramic substrate, and obtaining an activated ceramic substrate and a SiC chip; the surfaces of the activated ceramic substrate and the SiC chip are spin-coated with nano-silver paste, and a nano-porous silver layer is formed through pre-curing and low-temperature sintering; aligning the graphene / nano-porous silver composite layer chip with the ceramic substrate, performing segmented pressure sintering in a vacuum sintering furnace, and outputting a SiC power module; the SiC power module is subjected to epoxy resin packaging glue coating, ultraviolet light curing and annealing treatment, internal stress is eliminated, and the corrosion resistance is enhanced; and screening a SiC power module, performing XRD and SEM detection, coating a high-temperature-resistant silica gel sealing layer, performing curing, and outputting a finished product. Through the epoxy resin packaging adhesive coating and thermal-acoustic combined annealing technology, the residual stress of the packaging interface is released, the service life of the SiC power module is prolonged, and the adaptability of the SiC power module is improved.

The invention discloses a recrystallized silicon carbide ceramic tube. The recrystallized silicon carbide ceramic tube is prepared from silicon carbide powder comprising three components of recrystallized silicon carbide powder, 100F powder and powder with D50 of 20-25 microns through the processes of mixing, aging, pugging, extrusion forming, microwave drying and vacuum sintering. Compared with a two-component recrystallized silicon carbide ceramic, the multi-component silicon carbide powder can reach the maximum bulk density, so that the mechanical property of the recrystallized silicon carbide ceramic is improved. Compared with two-component recrystallized silicon carbide ceramics, the recrystallized silicon carbide ceramic tube prepared by the invention has the advantages that the high-temperature bending strength is averagely improved by 128 MPa, and the improvement rate is 177%; the compressive strength is averagely improved by 152MPa, and the improvement rate is 104%; the heat conductivity coefficient is averagely improved by 99W / m.K, and the improvement rate is 69%. And the material is especially suitable for key equipment in semiconductor and photovoltaic production processes. And the preparation process is mature and is beneficial to industrialization.

The invention discloses a gradient pressing and pore interlocking titanium-aluminum composite profile preparation method which comprises the following steps: S1, density differential pressing of titanium powder, unequal-thickness powder filling is carried out in a cavity, and a gradient density titanium material layer is formed through pressing; s2, primary sintering is conducted, specifically, the titanium material layer with the gradient density in the step S1 is sintered; s3, aluminum powder is pressed, specifically, aluminum alloy powder is added into the mold for secondary pressing compounding to form an aluminum material layer, and the aluminum powder permeates to the surface of the loose layer; and S4, secondary sintering permeation enhancement is carried out, vacuum sintering and pressure sintering are carried out, the aluminum material layer is in a semi-molten state in the sintering process, and on the basis of the capillary action principle, the aluminum material permeates and fills pores in the loose layer to form pore interlocking. The gradient structure with the compact outer side and the porous inner side is formed on the titanium layer through an unequal-thickness mold and step-by-step pressing, directional pores preset in the porous layer provide channels for aluminum permeation, and the permeation depth reaches 150 microns and is increased by three times compared with a conventional process.

The invention discloses a low-cost high-polishing titanium alloy plug housing injection molding method, and belongs to the technical field of metal injection molding. The method comprises the following steps: powder preparation, raw material weighing, internal mixing, granulation, injection molding, acid degreasing, thermal degreasing and vacuum sintering, and polishing. Titanium alloy powder used in the method is composite powder formed by adding 0-50 [mu] m non-spherical powder into 0-60 [mu] m spherical powder prepared through a plasma atomization method (PDPA). The cost of the non-spherical titanium powder is far lower than that of spherical titanium powder, and the production cost is relatively reduced by more than 80%; the 0-60 [mu] m spherical powder prepared by the plasma atomization method is high in powder permeability, and sintering densification is facilitated; the sintering shrinkage coefficient of the porous titanium alloy part with the complex shape prepared through vacuum sintering is accurately controlled to be 1.20-1.350, and extra shaping matched equipment is not needed; according to the high-polishing titanium alloy product part manufactured through the method, the density is larger than or equal to 4.45 g / cm < 3 >, the tensile strength is larger than or equal to 950 MPa, the elongation after fracture is larger than or equal to 12%, and the hardness is larger than or equal to 350 (HV).

The invention relates to a preparation method of a multilayer alloy net electrode for hydrogen production by alkaline electrolysis of water and the multilayer alloy net electrode, and the preparation method comprises the following steps: firstly, selecting an alloy electrode net material, then etching the alloy electrode net, and carrying out electrochemical etching by taking the alloy electrode net as an anode and an inert electrode as a cathode and using 0.5-5M acid liquor to prepare the multilayer alloy net electrode. The preparation method comprises the following steps: sequentially overlapping a first layer of pure nickel net with the mesh number of 80-200 and a second layer of etched alloy electrode net with the mesh number of 40-80 and a third layer of etched alloy electrode net with the mesh number of 20-40, carrying out vacuum sintering at 800-1400 DEG C for 2-5 hours, and finally stirring and drying in a polyethyleneimine aqueous solution. Compared with the prior art, the obtained electrode has the advantages of being low in cost, high in catalytic activity, fast in bubble removal, high in durability and stability and the like, effectively solves many problems of an existing alkaline water hydrogen production electrode, has a wide application prospect in the field of alkaline water electrolysis hydrogen production, can remarkably improve the water electrolysis efficiency and is beneficial to large-scale industrial production.

The invention discloses an AMB copper-clad ceramic substrate and a welding method thereof.The welding method comprises the steps that metal powder containing inactive elements Ag and Cu and an active element Ti is mixed with an organic carrier, and active soldering paste is obtained; and coating the active soldering paste on the surface of a ceramic substrate, stacking copper foils on the surface, coated with the active soldering paste, of the ceramic substrate, and performing vacuum sintering to obtain the AMB copper-clad ceramic substrate. According to the AMB copper-clad ceramic substrate and the welding method thereof provided by the invention, the process is improved when the AMB realizes metallization of the ceramic substrate, so that the obtained AMB copper-clad ceramic substrate has the characteristics of high interface bonding force, low warping degree and voidage, excellent cold and hot impact resistance and the like.

The invention discloses a tungsten-zirconium active material and a preparation method thereof. The method comprises the following steps: 1, mixing tungsten powder, nickel powder, iron powder and zirconium hydride powder to prepare mixed powder; 2, carrying out one-time compression molding on the mixed powder by adopting a cold isostatic press to obtain a pressed blank; 3, performing vacuum dehydrogenation treatment on the pressed blank by adopting a vacuum degumming furnace to obtain a pre-sintered blank; and 4, carrying out vacuum sintering on the pre-sintered blank by adopting a vacuum sintering furnace to prepare the tungsten-zirconium active material. The powder metallurgy method is adopted, densified sintering is achieved at the low sintering temperature, the problems of tungsten component sedimentation and zirconium powder oxidation are avoided, the tungsten content and the structure uniformity in the tungsten-zirconium active material are improved, the tungsten-zirconium active material with the tungsten mass content as high as 80% is obtained, the material has the remarkable damage effect, armor piercing after-effect is provided for damaged bullet seeds, and the application range of the tungsten-zirconium active material is widened. The method is suitable for the weapon manufacturing field.

The invention provides a Y-rich rare earth permanent magnet and a preparation method and a magnetic performance improving method thereof, and the performance improving method comprises the steps: uniformly mixing to-be-diffused metal powder containing Dy and / or Tb elements with an organic solvent to obtain to-be-diffused alloy liquid; the alloy liquid to be diffused is attached to the surface of the Y-rich rare earth permanent magnet, and the Y-rich rare earth permanent magnet is placed in a vacuum sintering furnace; the Y-rich rare earth permanent magnet is subjected to grain boundary diffusion heat treatment through the vacuum sintering furnace, so that Dy and / or Tb elements are diffused into the surface layer of a main phase lattice of the Y-rich rare earth permanent magnet; and carrying out tempering treatment on the Y-rich rare earth permanent magnet. The problems that the coercive force of an existing Y-containing magnet is difficult to effectively improve, and residual magnetism is easily reduced can be effectively solved.

The invention discloses a method for preparing an upper electrode of a gallium arsenide solar cell for a low-cost space, which comprises the following steps of: corroding a gallium arsenide epitaxial wafer taking germanium as a substrate in a mixed acid corrosion solution, removing an oxide layer and pollutants on the surface of the epitaxial wafer, taking out the epitaxial wafer, and cleaning the epitaxial wafer in deionized water; the surface of the active layer of the epitaxial wafer is tightly attached to the metal grid mesh, the epitaxial wafer is put into vacuum evaporation equipment, electrode metal is evaporated layer by layer in an electron beam evaporation mode, and after evaporation is completed, the epitaxial wafer is taken out from the vacuum evaporation equipment when the epitaxial wafer is cooled to 100 DEG C or below; and placing in a vacuum sintering furnace, heating at a constant temperature for a period of time, cooling to below 100 DEG C, and taking out to obtain the space gallium arsenide solar cell top electrode. A traditional photoetching process is replaced by a metal grid mesh, the surface of an active layer of an epitaxial wafer is tightly attached to the metal grid mesh, and then the epitaxial wafer is put into a vacuum coating machine to be subjected to metal evaporation. And the evaporated metal is deposited on the surface of the epitaxial wafer through gaps of the grid mesh to prepare a conductive upper electrode.

The invention relates to the technical field of cable preparation, in particular to a superconducting semi-rigid cable made of high-purity aluminum and a preparation method thereof.The method comprises the steps that the high-purity aluminum is adopted as an inner conductor, and the inner conductor is preprocessed; coating the surface of the pretreated inner conductor with a PTFE mixture by using a pushing machine at normal temperature to obtain a normal-temperature pushing core wire; the qualified normal-temperature pushing core wire is wound on a cable reel and then placed in a vacuum high-temperature furnace to be subjected to vacuum sintering so as to obtain an inner conductor wrapped with an insulating layer; and the inner conductor wrapped with the insulating layer penetrates into the processed pure aluminum outer conductor tube, and the outer conductor is wrapped with PTFE to form an outer protective sleeve. According to the invention, the performance stability of the superconducting semi-rigid cable preparation can be improved.

The invention belongs to the field of aluminum-based composite material recycling, and particularly relates to an aluminum-based composite material machining chip recycling method which comprises the steps that oil stains and floating dust on the surfaces of machining chips are removed, and the machining chips are crushed into sheets; carrying out alkali washing and acid washing cleaning to remove an oxide layer; determining a reinforced phase mass fraction through pickling; stirring the flaky material, and performing gravity settling to obtain particles arranged in parallel; performing low-temperature vacuum sintering to obtain a billet; and the aluminum-based composite material with high interface bonding strength and good uniformity is prepared through high-temperature plastic deformation. And the particle reinforced aluminum matrix composite material processing chips are recycled, so that the machining loss is reduced. And the oxide layer is removed, and the particle sintering difficulty is reduced. And the processing chips are arranged in parallel, so that the problems that the sheet-shaped aluminum-based composite material particles are not dense in hot pressing and easy to generate pores due to high strength are solved, and a new scheme is provided for recycling and reusing the composite material.

The invention provides a preparation method of a boron nitride setter plate, and belongs to the technical field of boron nitride setter plates. The preparation method comprises the steps of material mixing, cold isostatic pressing forming and vacuum sintering. The material mixing step comprises the following steps: putting hexagonal boron nitride powder with the particle size of 100-200nm, hexagonal boron nitride powder with the particle size of 1.0-3.0 mu m, hexagonal boron nitride powder with the particle size of 4.0-10.0 mu m, ammonium bicarbonate, phenolic resin and sodium tripolyphosphate into a ball-milling device, adding absolute ethyl alcohol for ball-milling treatment, then adding a secondary compound for continuous ball-milling for 23-28min, and after ball-milling is finished, cooling to room temperature to obtain the boron nitride composite material with the particle size of 100-200nm, the particle size of 1.0-3.0 mu m, the particle size of 4.0-10.0 mu m and the particle size of 1.0-3.0 mu m and the particle size of 4.0-10.0 mu m. Drying at 87-92 DEG C to obtain dry powder; the boron nitride setter plate prepared by adopting the method disclosed by the invention is high in mechanical strength and strong in toughness, and can still keep relatively high mechanical strength after repeated cold and heat cycles.

The invention provides a titanium alloy with high polishing property and a design and preparation method thereof. The design and preparation method comprises the following steps: firstly, mixing Ti-6Al-4V titanium alloy powder with a certain proportion of binder; then, the obtained feed is subjected to injection molding through an injection machine and a stretching strip mold, and a green body is obtained; and then, the green body is degreased. And finally, sintering in a vacuum sintering furnace according to a certain sintering process to obtain a final sintered part sample. The densification of the sintered sample and the regulation and control of the microstructure of the sintered sample are realized by adjusting the sintering process, so that the polishing property of the titanium alloy is improved. According to the titanium alloy with the high polishing property and the design and preparation method of the titanium alloy, different sintering processes are adopted, sintering densification of titanium alloy parts is achieved, the influence rule of the sintering processes on the microstructure of the titanium alloy is discussed, and therefore the polishing property of the titanium alloy parts is improved.