43results about How to "Lower densification temperature" patented technology

The invention discloses a method for preparing a compact ultrafine-grain boron carbide ceramic material with a reduced sintering temperature. The method comprises the following steps: selecting coarse boron carbide powder with an average particle size of less than 20 [mu]m and carrying out ball milling and settlement so as to obtain ultrafine boron carbide powder with a particle size of less than 1 [mu]m; mixing the ultrafine boron carbide powder with MnNiCoCrFeX high-entropy alloy powder and carrying out ball milling so as to obtain B4C-MnNiCoCrFeX mixed powder; and subjecting the mixed powder to pressure sintering so as to obtain the compact ultrafine-grain boron carbide ceramic material with a reduced sintering temperature. According to the invention, the MnNiCoCrFeX high-entropy alloy powder is added into a boron carbide matrix, so a liquid phase is formed during high-temperature sintering and can fill in pores, and thus, the sintering densification temperature of the boron carbide ceramic material is effectively reduced, and energy consumption is decreased; and a boron carbide product with a density of greater than 99% is obtained after a temperature of 1900 DEG C is maintained for 5 min, and compared with the prior art, sintering temperature is reduced by 200 DEG C and heat preservation time is substantially shortened.

The invention discloses a preparation method of a high-thermal-conductivity silicon nitride substrate, which belongs to the technical field of ceramic material preparation. Silicon nitride powder is adopted as a raw material, rare earth oxide and alkaline earth metal oxide are added to serve as a mixed sintering aid, the adding amount is 6 wt%-10 wt%, a high-molecular compound is added, ball milling and mixing are conducted in an organic solvent, and slurry is formed. Tape casting is carried out to form a green body, presintering of the green body in nitrogen at 1400-1600 DEG C for 1-5 hours is conducted, and heat preservation in an air pressure sintering furnace at 1800-2000 DEG C for 2-10 hours is carried out under the nitrogen pressure of 0.5-3 MPa. The silicon nitride powder used in the invention is high-purity alpha-phase silicon nitride, has very high specific surface area and high sintering activity, and can effectively reduce the densification temperature. The added high-molecular carbon-containing compound is a multi-component compound and is degreased and pre-sintered in an inert atmosphere, so that the thermal conductivity of the product can be improved. The thermal conductivity of the prepared silicon nitride ceramic substrate is not lower than 90 W/m.K, and the bending strength is not lower than 800 MPa.

The invention relates to the field of boride ceramics, and particularly provides a method for preparing a compact titanium diboride (TiB2) bulk material with ternary layered carbide titanium aluminum carbon (Ti3AlC2) as a sintering aid at a low temperature. By adopting the method of the invention, a problem that titanium diboride ceramic is difficult to sinter can be solved. The method comprises the steps of adopting TiB2 powder and Ti3AlC2 powder with different mass ratios as raw materials, mixing the raw materials for 5-40h through a physical mechanical method, cold pressing to a cake shapeat a pressure of 5-20Mpa, placing into a graphite mould and heating to 1400-1600 DEG C and reacting for 0.5-4h in situ at a pressure of 20-40MPa under the circumstance that an inert gas is introducedto serve as protective atmosphere. By adopting the method provided by the invention, the TiB2 ceramic material with excellent mechanical property can be synthetized at a low temperature.

The invention relates to silicon nitride ceramic with hard outside and tough inside and a preparation method thereof. The Si3N4 ceramic with hard outside and tough inside comprises three layers of silicon nitride ceramic; wherein the middle layer is an inner layer, and the upper and lower layers are outer layers; the main phase of the inner layer is beta-Si3N4, preferably, 88-89.5 wt% of silicon nitride powder is used as a raw material, 10.5-12 wt% of Al2O3-Er2O3-ZrSi2 is used as a sintering aid, and the inner layer is prepared through hot pressed sintering; the main phase of the outer layer is alpha-Si3N4, preferably, 60.5-71.5 wt% of silicon nitride powder is used as a raw material, 8.5-9.5 wt% of Al2O3-Nd2O3-LiF is used as a sintering aid, 20-30 wt% of TiC is used as a second phase, and the outer layer is obtained through secondary hot pressing sintering.

The invention discloses high flux ferrite powder capable of reducing cracking. The raw materials of the high flux ferrite powder capable of reducing the cracking comprise the following components in parts by mole: 51.0 to 55.0 parts of iron sesquioxide, 21.0 to 25.0 parts of zinc oxide, and 20.0 to 28.0 parts of manganese oxide; glue with 0.7 to 1.5 weight parts of solid is added and a certain weight of an inert nano-composite material. Polyvinyl acetate with the glass transition temperature of less than 40 DEG C is added so that the one-dimensional compressibility of the powder is greatly improved; the inert nano-composite particles which are prepared by the main components of nano-amorphous iron oxide (or hydroxyl ferric oxide) and manganous-manganic oxide are adopted, so that the a gluedischarging channel can be provided in an early stage, and the inert nano-composite particles can be molten in original crystal particles without affecting the main component of the ferrite in a lateperiod; and the wear of slurry and a spraying piece of a spraying gun of a spraying tower can be reduced by performing spray-granulating by adopting the ferrite slurry which is coated by the inert nano-material which is coated by adopting a resistance reducing agent, namely a hydroxyethyl cellulose solution, so that the cost is reduced, and meanwhile, the size consistency of the particles is improved.

The invention relates to a vacuum impregnation coating method and device for planar solid oxide fuel cell (SOFC) electrolyte. The method comprises the step of impregnating a planar solid oxide fuel cell supporting body into electrolyte slurry under a vacuum state, wherein the supporting body can keep still so as to lift a slurry tank containing the electrolyte slurry in the impregnation process. The method not only can be used for preparing a large-area anode supporting panel SOFC, but also can be used for preparing a large-area cathode supporting panel SOFC.

The invention discloses a preparation method of high thermal conductivity and high strength aluminum nitride ceramics, belonging to the technical field of preparation of ceramic materials. According to the preparation method, aluminum nitride powder with a primary particle size less than 200nm is used as a raw material; an oxide or a halide of a rare earth metal is added as a sintering aid, and the adding amount is 1-6wt%. The method comprises the steps of mixing and molding the raw material powder, then pre-sintering for 1-5h at the temperature of 1300-1500 DEG C in a nitrogen-containing reducing atmosphere under the normal pressure, and then sintering for 3-10h at the temperature of 1500-1800 DEG C in a nitrogen atmosphere. The prepared aluminum nitride ceramics has a grain size of lessthan 3mu m, a thermal conductivity of not less than 150W/m.K, a bending strength of not less than 500MPa, and a hardness of not less than HRC 88.

The invention provides a microwave dielectric ceramic material as well as a preparation method and application thereof. The microwave dielectric ceramic material comprises two materials, namely Zn3B2O6 and Mg3B2O6, the molar ratio of Zn3B2O6 to Mg3B2O6 is (1-x): x, and x is equal to 0.05-0.40. The microwave dielectric ceramic material is prepared from the following oxides in percentage by mole: 71.25-45.00% of a main material ZnO, 25.00% of a main material B2O3, and 3.75-30.00% of a substitute material MgO, wherein the sum of the molar percentages of the components is 100%, and the molar ratioof ZnO to MgO is (0.95: 0.05)-(0.60: 0.40). The microwave dielectric ceramic material has the excellent characteristics of low dielectric constant, high quality factor, high relative density, relatively stable temperature characteristic and low densification temperature.

A pressureless sintering preparation method of Ti2SC ceramic is characterized by comprising the following steps: (1) evenly mixing Ti2SC ceramic powder with polyvinyl alcohol PVA, and then filling into a die for preforming; (2) performing cold isostatic pressing treatment on the preformed Ti2SC ceramic; (3) putting the cold isostatic pressing treated Ti2SC ceramic into a microwave sintering furnace filled with inert gas protective atmosphere for sintering for 20-60 minutes at 800-1100 DEG C to obtain the Ti2SC bulk ceramic; the preparation method not only improves the density of the ceramic material, realizes the controllable density of the Ti2SC ceramic material, can prepare Ti2SC ceramic materials with complex shapes, and has the advantages of low sintering temperature, short time, saving energy and the like.

The invention discloses a preparation method of a continuous-fiber reinforced carbon/carbon-molybdenum composite material. The preparation method comprises the following steps: (1) scattering molybdenum powder on the surface of each carbon fiber felt and each carbon-fiber non-woven fabric on each layer uniformly to obtain carbon fiber felts with molybdenum powder and carbon-fiber non-woven fabrics with molybdenum powder, superposing the carbon fiber felts with molybdenum powder and the carbon-fiber non-woven fabrics with molybdenum powder layer by layer alternatively, and weaving to obtain a molybdenum containing carbon fiber preform; (2) putting the molybdenum containing carbon fiber preform obtained in the step (1) into a depositing furnace, and depositing with pyrolytic carbon to obtain a molybdenum containing carbon/carbon composite blank with pyrolytic carbon, wherein the pyrolytic carbon is in a coarse layered structure, and the temperature is controlled at 1,170-1,220 DEG C in the process of depositing with pyrolytic carbon; and (3) putting the molybdenum containing carbon/carbon composite blank into an SPS (spark plasma sintering) furnace, increasing the temperature to 1,750-1,850 DEG C, pressing, and preserving temperature and pressure under pressure to obtain the continuous-fiber reinforced carbon/carbon-molybdenum composite material.

The invention aims to prepare an aluminum nitride ceramic material with high strength and high thermal conductivity, and belongs to the technical field of ceramic material preparation. In order to obtain the aluminum nitride ceramic with low oxygen content and fine grain structure, a novel method of pre-sintering, hot pressed sintering and high-temperature annealing is designed, wherein the pre-sintering temperature is 1400-1600 DEG C, the sintering time is 2-5 hours, the hot pressing sintering temperature is 1650-1800 DEG C, the sintering time is 0.5-3 hours, the sintering pressure is 15-45 MPa, the annealing temperature is 1750-1800 DEG C, and the annealing time is 3-8 hours. According to the method, presintering oxygen reduction and annealing deoxidation are utilized, so that the impurity oxygen content, especially the lattice oxygen content, of the aluminum nitride ceramic is effectively reduced. Therefore, under the condition of ensuring the strength, the heat conductivity of the aluminum nitride ceramic is remarkably improved, and the aluminum nitride ceramic has high practical value. The ceramic prepared by the method has the advantages of fine grains and low impurity oxygen content, the average grain size is less than 3 microns, the thermal conductivity is higher than 200W/m.k, the total oxygen content is lower than 1%, and the bending strength is higher than 350MPa.

The invention discloses a preparation method of a barrier layer yttrium oxide-doped bismuth oxide of a solid oxide fuel cell, and belongs to the technical field of preparation of a battery material. The preparation method comprises the following steps of 1, taking Bi(NO<3>).5H<2>O and Y(NO<3>).6H<2>O as the raw materials, and preparing Y<x>Bi<2-x>O<3> powder through a coprecipitation method; 2, adding ethyl cellulose into Y<x>Bi<2-x>O<3>; 3, adding terpilenol, and grinding for 10-30min through an agate mortar; 4, performing silk screen printing on the obtained Y<x>Bi<2-x>O<3> paste on an electrolyte; 5, performing drying; 6, performing silk screen printing and drying for 1-3 times repeatedly to obtain Y<x>Bi<2-x>O<3> barrier layers of different thicknesses; and 7, performing heat treatmenton the electrolytes of the Y<x>Bi<2-x>O<3> barrier layers. The preparation method has the advantages as follows: by taking Y<x>Bi<2-x>O<3> with high oxygen ionic conductivity as the barrier layer, the problem of mismatching of coefficients of thermal expansion between a negative electrode and the electrolyte and between the barrier layer and the electrolyte can be effectively relieved, a reactionbetween a cobalt-based and a barium ferrite-based negative electrode material and a zirconium-based electrolyte can be avoided, and the interface resistance can be lowered; and the preparation methodis free of complex equipment, simple in preparation process, low in cost, and amplification and popularization can be realized easily.

The invention discloses a preparation method for a continuous fiber-reinforced carbon/carbon-niobium composite material. The method comprises the following steps: (1), uniformly dispersing niobium powder on the surface of each layer of carbon fiber web and carbon fiber non-woven cloth to obtain carbon fiber web layers and carbon fiber non-woven cloth layers with niobium powder; then crosswise laying and weaving the obtained carbon fiber web layers and carbon fiber non-woven cloth layers with the niobium powder layer by layer to obtain a niobium-containing carbon fiber preform; (2), performing pyrolytic carbon deposition on the niobium-containing carbon fiber preform obtained in step (1) in a deposition furnace to obtain a niobium-containing carbon/carbon composite blank with pyrolytic carbon, wherein the pyrolytic carbon is pyrolytic carbon with a rough laminar microstructure, and the temperature is controlled to be 1,100 to 1,150 DEG C when the pyrolytic carbon is deposited; (3), heating the niobium-containing carbon/carbon composite blank to 1,670 to 1,720 DEG C in an SPS furnace, applying pressure, and preserving heat and pressure to obtain the continuous fiber-reinforced carbon/carbon-niobium composite material under a pressure condition.

The invention provides a gallium oxide doped tin oxide ceramic target material and a preparation method thereof. The gallium oxide doped tin oxide ceramic target material comprises the following raw materials in percentage by mass: 2-10% of gallium oxide and 90-98% of tin oxide high-purity nano powder. The preparation method comprises the following steps: weighing and mixing the powder, adding ammonium polyacrylate, polyvinyl alcohol and pure water, carrying out ball milling on the mixed slurry, granulating, drying to obtain mixed powder, sequentially carrying out compression molding by using an oil press and an isostatic press, and preparing the gallium oxide-doped tin oxide ceramic target material at different sintering temperatures by using a degreasing multi-step sintering integrated sintering technology. According to the doped gallium oxide, the sintering performance of the tin oxide ceramic is effectively improved, the density of the tin oxide ceramic target material is remarkably improved, and meanwhile the gallium oxide doped tin oxide target material which is uniform in structure and fine in grain is obtained through effective control over the preparation process.

The invention discloses preparation and application of silicon-based low-dielectric high-quality-factor microwave dielectric ceramic capable of being sintered at low temperature. The preparation comprises the steps: (1) weighing and proportioning Li2CO3, SrCO3 and SiO2 according to the composition of Li2SrSiO4; (2) ball-milling and mixing for 6 hours by using alcohol as a ball-milling medium, drying and then pre-sintering; and (3) weighing the pre-sintered powder and SiTiO3 powder according to (1-x)Li2SrSiO4-xSrTiO3 (wherein x is the volume percent (0<=x<=0.06)), after ball milling is carried out again, adding a polyvinyl alcohol solution is added, carrying out granulation, carrying out compression molding, and finally sintering in the air atmosphere. The prepared silicon-based low-dielectric high-quality-factor microwave dielectric ceramic has the dielectric constant of 7.4-8.2, the quality factor up to 63,200-100,700 GHz and the temperature coefficient of resonance frequency close to zero, and can be applied to manufacturing of microwave components such as various ceramic substrates, dielectric resonators and filters.

The invention relates to a preparation technology of layered ceramic, in particular to a compact layered silicon carbide ceramic and a preparation method thereof. According to the compact layered silicon carbide ceramic, lamellar silicon carbide ceramics are used as basic units, and each basic unit is of a structure with more than three layers connected by discrete silicon carbide ceramic columns in a laminated manner; in the layered silicon carbide ceramic, the relative density of the silicon carbide ceramic basic units and the silicon carbide ceramic columns is greater than or equal to 99%; the silicon carbide ceramic basic units and the silicon carbide ceramic columns are composed of, by weight, 90%-98% of silicon carbide and 10%-2% of silicon, and the average grain size ranges from 50 nm to 50 microns. According to the compact layered silicon carbide ceramic and the preparation method thereof of the invention, the layered structure gaps of the layered silicon carbide ceramic are filled with tough phases(such as metal, polymer and the like), so that when the layered silicon carbide ceramic bears an impact load, the transmission path and the expansion mechanism of cracks can be changed, the sensitivity of the material to the cracks is reduced, and the toughness of the ceramic is further improved.

Disclosed is a method for forming a solid state electrolyte. The method includes a first step of combining a solid comprising lithium, a second solid comprising lanthanum, a third solid comprising zirconium, and a fourth solid comprising bismuth to form a mixture. The method includes a second step of applying simultaneous heat and pressure to the mixture to form a ceramic material. The solid state electrolyte is ionically conducting and can be used as an electrolyte for an electrochemical device such as a battery or supercapacitor.

A formation method of a semiconductor structure comprises the following steps: providing a substrate, wherein fin parts are arranged on the substrate, and a fin part gap is kept between every two adjacent fin parts; arranging a hard mask above the fin parts; forming a punchthrough-proof layer above the hard mask, wherein the punchthrough-proof layer is filled with punchthrough-proof ions; formingan anti-spreading layer which is lower than the fin parts, and injecting anti-spreading ions into the fin part gaps, wherein the anti-spreading ions can prevent the punchthrough-proof ions from beingspread to the tops of the fin parts; removing the hard mask; and annealing.