25 results about "Uniaxial pressure" patented technology

The invention belongs to the technical field of composite ceramics, and discloses a CoSi2 alloy toughened high-entropy carbide composite ceramic as well as a preparation method and application thereof. The composite ceramic is (Ti0. 2Zr0. 2Nb0. 2Ta0. 2Mo0. 2) C-CoSi2, and is prepared by the following steps: mixing TiO2 powder, ZrO2 powder, Nb2O5 powder, Ta2O5 powder, MoO3 powder and carbon powder to obtain mixed powder, adding the mixed powder into absolute ethyl alcohol, stirring to obtain slurry, carrying out ball milling, drying and sieving, carrying out dry pressing to obtain a green body, sintering at 1000-1600 DEG C in a protective atmosphere, mixing the prepared high-entropy powder and CoSi2 powder, carrying out ball milling, drying and sieving, and carrying out dry pressing to obtain a green body; the composite ceramic is prepared through SPS sintering under the uniaxial pressure of 25-30 MPa and at the temperature of 1500-1700 DEG C. The composite ceramic has the advantages of high density, high hardness, high fracture toughness and the like, and can be applied to the field of preparation of materials difficult to cut.

Various embodiments of the teachings herein include a method for producing a rotationally symmetrical magnetic sheet having a plurality of radially running winding teeth for a laminated core of an electric machine. An example includes: producing a green body by applying a printing paste onto a substrate using a stencil printing method, wherein the printing paste comprises binders and iron particles having more than 95 wt. % of iron; producing a preform from the green body using a first thermal treatment wherein the binders are removed from the green body; producing the magnetic sheet from the preform using a second thermal treatment including a sintering process; and pressing the magnetic sheet with a pressure of more than 5 MPa in a uniaxial manner in the sheet plane thereof with a pressing ram. The pressing generates an anisotropic texture in the winding teeth.

This invention discloses a rapid, high-strength microwave bonding method for ceramics and cemented carbide, belonging to the field of ceramic material bonding technology. The method includes the following steps: preparing a metal solder; grinding, polishing, and cleaning the bonding surfaces of the ceramic and cemented carbide respectively; loading the prepared metal solder into a mold and pressing it under uniaxial pressure to obtain a metal solder sheet; placing the ceramic, metal solder sheet, and cemented carbide in a stacked structure in a microwave sintering furnace for microwave sintering to achieve the bonding of the ceramic and cemented carbide. Compared with traditional brazing and diffusion welding, this ceramic-cemented carbide microwave bonding method increases the heating / cooling rate by 6-10 times, improves the single-furnace bonding efficiency by 5-9 times, allows for mass production, and yields ceramic-cemented carbide bonding interfaces with high strength. This invention significantly improves production efficiency, reduces energy consumption, and has widespread application value.

A method for manufacturing a part by alloying a precious metal with boron, wherein: a quantity of precious metal reduced to powder form is provided; a quantity of a nano-structured micrometric boron powder is provided; the precious metal powder is mixed with the nano-structured micrometric boron powder to obtain a mixture; the mixture is compacted by applying a uniaxial pressure; the mixture is subjected to a spark plasma sintering or flash sintering treatment, or to a hot isostatic pressing (HIP) treatment, to obtain an ingot of a precious metal / boron alloy, and the ingot is machined to obtain the part, or the ingot is reduced to powder form by a micronisation treatment and the powder is treated to obtain the part. Additionally, a gold / boron alloy.

The invention discloses a method for testing uniaxial compression mechanical properties of prefabricated fractured rock under the action of acid etching, which comprises the following steps: S1, preparing a sample, and taking deteriorated sandstone; s2, preparing a rock sample, namely preparing the modified sandstone into a standard cylindrical sample of phi 50 mm * 100 mm, and making a prefabricated fracture in the geometric center of the sample; s3, preparing a corrosive liquid with the pH value of 2; s4, dividing the rock samples prepared in the step S2 into two groups according to a fracture inclination angle alpha, wherein each group comprises four rock samples; wherein one group is used as a control group, is placed in air at room temperature for 48 hours and then is subjected to a uniaxial compression test; the other group of samples are immersed in the acidic solution with the pH value of 2 obtained in the step S3, four samples are obtained under each condition, and the samples are immersed for 20 d under the condition that the container is sealed; s5, performing a uniaxial compression test on a uniaxial compression testing machine; and S6, observing the rock sample damaged in the compression test by using Axia Chemi SEM to obtain the fracture development condition.

The application relates to a low-temperature connecting method of electric field assisted flash soldering of conductive ceramics under an air atmosphere, and relates to a low-temperature connecting method of ceramics. The application aims at solving the problems of high connecting temperature, long connecting time and high environmental atmosphere requirement of the existing common ceramic connecting method. The method comprises the following steps: 1, pretreatment; 2, placing the pretreated soldering material sheet between two pieces of pretreated ceramics, setting electrodes connected with an external power supply on the upper and lower surfaces of the connecting piece, placing the connecting piece and the electrodes arranged on the surfaces between the upper and lower pressing heads of a connecting furnace, and applying uniaxial pressure; 3, adjusting the current value before connection, heating the connecting furnace to the connecting temperature, increasing the voltage until the ceramics are conductive, and then connecting under the specific current. The application is used for the low-temperature connection of electric field assisted flash soldering of conductive ceramics under an air atmosphere.

This invention relates to a transparent strontium fluoride ceramic based on low-temperature sintering, its preparation method, and its applications. The transparent strontium fluoride ceramic, by mass percentage, consists of 95-99% strontium fluoride matrix and 1%-5% thermosensitive luminescent material. The method of this invention uses a mild strontium acetate solution as a sintering aid, and successfully prepares a transparent strontium fluoride ceramic with a density greater than 99% and high optical transmittance under a low temperature of 100-150 °C and a uniaxial pressure of 300-400 MPa. The low-temperature sintering process of this invention avoids damage to the material from strong acids and alkalis, allows the thermosensitive luminescent material to be incorporated into the ceramic matrix during sintering, effectively preserving the excellent properties of the luminescent material and exhibiting excellent optical performance and encapsulation protection.

Embodiments of the invention are directed to a method for production of a nuclear fuel pellet by spark plasma sintering (SPS), wherein a fuel pellet with more than 80% TD or more than 90% TD is formed. The SPS can be performed with the imposition of a controlled uniaxial pressure applied at the maximum temperature of the processing to achieve a very high density, in excess of 95% TD, at temperatures of 850 to 1600° C. The formation of a fuel pellet can be carried out in one hour or less. In an embodiment of the invention, a nuclear fuel pellet comprises UO2 and a highly thermally conductive material, such as SiC or diamond.

The invention discloses a SiO2 ceramic bond grinding tool and a preparation method thereof. The preparation method comprises the following steps: uniformly mixing SiO2, Si powder and grinding materials; a Na2O.nSiO2 solution is added, and the mixed powder is fully wetted; and the wetted powder is placed in a mold, uniaxial pressure is applied, and sintering is carried out. The SiO2 ceramic bond grinding tool is prepared by adopting a sintering method, so that the sintering temperature of the ceramic bond is reduced, the grinding material is effectively protected, the manufacturing energy consumption is reduced, and the obtained grinding tool has excellent grinding, breaking strength and heat resistance.

The invention relates to the technical field of aluminum alloys, in particular to a high-strength aluminum alloy and a preparation method and application thereof.The preparation method comprises the following steps that steel balls, aluminum blocks and a lubricant are put into a ball mill, the ball mill is filled with inert gas, the aluminum blocks are crushed, epoxy zinc phosphate is sprayed, drying is conducted, and antioxidant aluminum powder is obtained; uniformly mixing the antioxidant aluminum powder with titanium nitride, boron carbide, nano zinc powder, vanadium powder, magnesium powder, calcium-aluminum alloy powder, zirconium dioxide powder, borax powder and gallium oxide powder to obtain a mixture; feeding into a product mold preset by a press for compacting to form a billet; putting the billet into a protective atmosphere sintering furnace, and sintering under the combined action of the temperature of 750-850 DEG C and uniaxial pressure to obtain a sintered aluminum alloy; and the high-strength aluminum alloy is obtained through extrusion, rolling and forging. The adverse effect of an aluminum oxide film is reduced through a specific method, metallurgical bonding is more easily formed between the raw materials and aluminum, the material interface is clean, the structure is compact, and the strength of the aluminum alloy is improved.

The application belongs to the technical field of composite ceramics, and discloses a CoSi2 alloy toughened high-entropy carbide composite ceramic and a preparation method and application thereof. 0.2 Zr 0.2 Nb 0.2 Ta 0.2 Mo 0.2 )C-CoSi2, wherein TiO2 powder, ZrO2 powder, Nb2O5 powder, Ta2O5 powder, MoO3 powder and carbon powder are mixed to obtain mixed powder, the mixed powder is added into anhydrous ethanol for stirring to obtain slurry, the slurry is subjected to ball milling, drying and sieving, and then is dry-pressed into a green body, the green body is sintered at 1000-1600 DEG C under a protective atmosphere, high-entropy powder and CoSi2 powder are mixed, the mixture is subjected to ball milling, drying and sieving, and then is dry-pressed into a green body, and the green body is sintered by SPS at 1500-1700 DEG C under a uniaxial pressure of 25-30 MPa, so that the composite ceramic has the advantages of high density, high hardness and high fracture toughness, and can be applied in the field of preparation of cutting difficult-to-machine materials.

The invention discloses a short-process preparation method of an aluminum-chromium alloy target material. The method comprises the following steps: 1, preparing a powder raw material; 2, uniformly mixing; 3, drying; 4, gradient heating and pressurizing SPS sintering; 5, coating hot rolling and annealing treatment; and 6, machining, straightening, vacuum annealing and cleaning treatment. According to the method, the SPS sintering process of gradient heating and pressurizing is adopted, the aluminum-chromium alloy target material blank which is completely alloyed and uniform and compact in structure is obtained, the preparation period is greatly shortened, the production efficiency is greatly improved, the good alloying effect is effectively guaranteed, the problems of grain growth and oxygen content increase caused by long-time sintering are solved, and the method is suitable for industrial production. By combining the coating hot rolling process and the annealing process, grains are further refined, the structure uniformity is improved, the problem of poor density uniformity caused by SPS uniaxial pressure is solved, meanwhile, expensive hot isostatic pressing equipment is prevented from being used, the production cost is greatly reduced, and the method is suitable for large-scale application and popularization.

The invention relates to SiC ceramic based on improved precursor impregnation and pyrolysis and current reinforced sintering densification printing biscuit and a preparation method thereof. The particles of the SiC ceramic are of a core-shell structure with SiC as a core and a SiC-AlN solid solution as a shell. The preparation method comprises the following steps: (1) carrying out binder jet printing on composite powder containing SiC and AlN to respectively obtain a porous SiC biscuit and a sacrificial mold biscuit which is in a negative geometrical shape with the porous SiC biscuit; (2) the porous SiC biscuit and the sacrificial mold biscuit are subjected to debonding, dipping, curing and cracking, and a porous SiC reinforced biscuit and a sacrificial mold reinforced biscuit are obtained; and (3) assembling the porous SiC reinforced biscuit and the sacrificial mold reinforced biscuit according to a geometrical shape corresponding relation to form an assembly part, performing current reinforced sintering under uniaxial pressure, and then removing the sintered sacrificial mold to obtain the SiC ceramic material.

The present invention relates to a sintering tool consisting of a press capable of applying uniaxial pressure to the powder being sintering that has been introduced into a die (1) by means of two opposing pistons (10, 20), characterized in that the proximal front surface of the pistons (10, 20) defining a sintering chamber (5) has a hemispherical shape (11, 21). It also relates to a method for manufacturing a part by sintering under load in a sintering chamber (5) defined by such a tool.

A system for the synthesis of pure bismuth ferrite calcium titanate mixed-solution ceramics, comprising: a) a mixing unit configured to homogenize stoichiometric amounts of bismuth oxide (Bi2O3), iron oxide (Fe2O3), calcium carbonate (CaCO3) and titanium dioxide (TiO2) with sodium chloride (NaCl) as flux in a weight ratio of 1:3 between the total oxide precursors and salt; b) a calcination unit configured to heat the homogenized mixture at 700°C for 2 hours; c) a cleaning system configured to wash calcined powders with deionized water to remove residual salts; d) a compaction unit configured to operate under a uniaxial pressure of 220 kg / cm² 2 at room temperature forms disc-shaped pellets; e) a sintering plant configured to sinter the pellets at 750 °C for 2 hours with controlled heating and cooling rates of 3 °C / min; and f) an electrode coating unit configured to apply silver paste to the pellet surfaces and allow them to dry for 30 minutes at 70°C.

The application belongs to the technical field of ceramic low-temperature sintering, and particularly relates to a low-temperature preparation method of nano alpha-Al2O3 ceramic. The application adopts a cold sintering process, takes aluminum hydroxide powder as raw material, and takes 2-20 wt.% deionized water as solvent to obtain dense alpha-AlOOH ceramic under 500-2000 Mpa uniaxial pressure, 200-500 DEG C heating temperature and 50-300 min holding time; then, through a low-temperature annealing process, complete phase change from alpha-AlOOH to alpha-Al2O3 is realized under 400-600 DEG C annealing temperature and 2-6 h holding time, and finally alpha-Al2O3 ceramic sintered body with 30-50 nm grain size is obtained. The method overcomes the technical difficulty that traditional alpha-Al2O3 ceramic sintering temperature is high and it is difficult to obtain nano-crystal structure ceramic sintered body, and provides a process method for preparing alpha-Al2O3 ceramic with nano-crystal structure at low temperature, which has short preparation period and strong operability.

The invention discloses a two-component reinforced iron-based composite material and a preparation method thereof. The method comprises the following steps: firstly, preparing SiC composite particles with BNNT grown on the surfaces, and then preparing cobaltocene cation dendritic macromolecule grafted carbon nanotube modified short carbon fibers; and then under the protection of nitrogen, SiC composite particles with BNNT growing on the surfaces are mixed with iron powder, chopped modified carbon fibers and absolute ethyl alcohol are added for continuous mixing and drying, the obtained mixed powder is pressed into a preformed blank, the preformed blank is heated at the temperature of 500-580 DEG C, 20-40 MPa uniaxial pressure is applied, and finally the iron-based composite material is obtained. Through the synergistic effect of the BNNT modified SiC particles and the graft modified carbon fibers, the interface bonding force, strength and fracture toughness of the composite material are improved, and the preparation process is simple, convenient and controllable.

The application belongs to the technical field of rock mechanics test, and particularly relates to a biaxial compression clamping device based on arc turning, which comprises symmetrically arranged upper loading assemblies and lower loading assemblies, and each of the upper loading assemblies and the lower loading assemblies comprises a loading block, a force transmission block and a clamping block. The force transmission block is connected with the bottom surface of the loading block through a first rolling assembly, and the bottom of the force transmission block is provided with a circular arc surface. The clamping block is arranged below the force transmission block, the top of the clamping block is in sliding connection with the circular arc surface, the inner side of the clamping block is provided with a jaw for clamping a test piece, the inner side of the jaw is provided with an antifriction plate, and the antifriction plate is connected with the clamping block through a second rolling assembly. Through the cooperative action of the upper loading assemblies and the lower loading assemblies, the device can apply bidirectional adjustable compression load to the test piece under the driving of uniaxial pressure, not only can the uniaxial testing machine simulate complex biaxial stress state, but also can effectively isolate the interference of test piece deformation on the load transmission path through multi-stage rolling antifriction.

The invention relates to the technical field of chip testing, in particular to a chip aging test board and a health state early warning method and system thereof, and the chip aging test board comprises an aging test board which comprises a substrate and a plurality of test sockets installed on the substrate, the back surface of the substrate is fixedly provided with a protection board, and the protection board is provided with through holes which are in one-to-one correspondence with the positions of the test sockets; the supporting plate comprises a bottom plate and a plurality of monitoring supporting columns arranged on the bottom plate; a uniaxial pressure sensor used for collecting acting force perpendicular to the supporting direction is integrated in each monitoring supporting column. And the data acquisition unit is electrically connected with all the uniaxial pressure sensors and is used for synchronously acquiring pressure signals generated when each test socket is subjected to downward pressure in each loading and unloading process. Each loading and unloading action is converted into detection of a test socket connection system through integrated sensors and an innovative signal processing algorithm; and the mechanical health state of the test socket can be perceived in a real-time, online and non-invasive manner.

The invention belongs to the technical field of microwave dielectric ceramic preparation, and particularly relates to a preparation method of a cold-sintering-assisted low-temperature densified KTaO3 ceramic material. The preparation method comprises the following steps: mixing KTaO3 powder with K2CO3 aqueous solutions with different concentrations and addition amounts, and combining specific uniaxial pressure, sintering temperature and heat preservation time to realize preliminary densification of the ceramic material; and then, the densification of the KTaO3 ceramic is further realized through annealing treatment at different temperatures. Compared with a traditional cold sintering method, the K2CO3 aqueous solution is used as a liquid phase medium, the solubility of the KTaO3 powder can be effectively improved, and the initial compactness degree is improved; compared with a traditional solid-phase sintering method, the densification temperature of the ceramic material can be remarkably reduced, volatilization of the K element can be reduced, and therefore generation of a second phase is avoided, the obtained ceramic material is excellent in dielectric property, the preparation technology is simple, energy consumption is reduced, and the good application prospect is achieved.

The present invention relates to a sintering tool comprising a press capable of applying uniaxial pressure to the powder being sintered, which is introduced into a die (1) by means of two opposing pistons (10, 20), characterized in that the proximal frontal surface of said pistons (10, 20), defining a compaction chamber (5), has a hemispherical shape (11, 21). It also relates to a method for manufacturing a part by load sintering in a compaction chamber (5) defined by such a tool. Abstract figure: Figure 3

The invention discloses a silicon carbide reinforced diatomite molten salt composite shaped phase change heat storage material and a preparation method thereof, and relates to the technical field of phase change materials. The composite material is composed of 60 wt.% of nano silicon carbide / salt and 40 wt.% of diatomite, and 3-11 wt.% of a sintering agent is added on the basis of the proportion. A sodium hydroxide solution serves as a sintering agent, and a cold sintering technology is adopted. In the cold sintering process, different mass fractions of nano silicon carbide are added into base salt, so that the heat conductivity coefficient of the cold-sintered composite sizing material can be effectively improved, and meanwhile, the cold-sintered composite sizing material has excellent heat storage performance and mechanical strength; and the optimal values of four cold sintering parameters including the sintering agent concentration, the cold sintering temperature, the uniaxial pressure and the cold sintering time are determined. Compared with a traditional cold sintering mode, the composite shaped phase change material prepared through the improved cold sintering method greatly reduces the situation that salt particles on the surface of a sample are melted and lost in the sintering process, and consequently the latent heat value of the composite material is excessively reduced.

The present invention discloses a hexagonal diamond and a preparation method thereof, and relates to the technical field of diamond preparation. A preparation method of hexagonal diamond, comprising the following steps: (1) applying quasi-uniaxial pressure: applying pressure to a graphite material in the directions of three dimensions x-y-z, wherein the pressure in the x-direction is 12-40GPa, the pressure in the y-direction is 12-40GPa, the pressure in the z-direction is 15-50GPa, and the pressure in the z-direction is greater than the pressure in the x-direction and the y-direction; (2) heating and temperature raising: heating the graphite material to 300-2000K, holding time is 1min-5h, i.e., obtaining hexagonal diamond. The hexagonal diamond prepared by the present invention has higher purity and better crystal structure.

The present invention discloses a rheological test device and test method for coal and rock masses. The device includes a rheological test main machine, which includes an axial loading device, a data acquisition system, a separately arranged uniaxial pressure chamber and confining pressure chamber; the confining pressure chamber includes an openable sealed chamber body, in which an upper bearing plate and a lower bearing plate are provided, and a pore sieve backing plate is provided on the upper surface of the lower bearing plate; a fluid inlet is provided on the lower bearing plate; the data acquisition system includes an axial displacement sensor and a radial displacement sensor arranged around the specimen. This application is provided with an independent uniaxial pressure chamber and confining pressure chamber, which are respectively used for uniaxial loading tests and triaxial loading tests, and can meet the mechanical property test requirements of specimens of different sizes. The confining pressure chamber can also conduct seepage tests at the same time, and various corresponding tests can be carried out on the specimen according to specific experimental schemes. The axial compression deformation and circumferential expansion deformation of coal and rock masses can be accurately measured, and the true deformation of coal and rock masses can be accurately measured.