11 results about "Uniaxial pressure" patented technology

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.

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.

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 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