171results about How to "Promotes sintering densification" patented technology

The invention discloses a method for preparing an extra-coarse grained carbide alloy. The method is characterized by comprising the following steps of: pre-mixing extra-coarse tungsten carbide powder having a grinding Fisher particle size of over 6 mu m and cobalt powder; adding molding agents and pressing the mixture to form lumps; pre-sintering the lumps in a degumming furnace having ammonia decomposition gas therein; placing the obtained product, the tungsten carbide powder and the cobalt powder into a ball mill for smashing and wet grinding to prepare a mixture containing 6 to 13 percent cobalt; adding molding agents into the mixture, and pressing to obtain the finished product; after degumming the finished product, sintering the finished product at the high temperature by using a pressurized sintering furnace; and thermally treating the sintered product by using a double-chamber high-pressure gas cooling vacuum furnace, wherein 87 to 94 parts of tungsten carbide, 6 to 13 parts of carbide powder and 0.5 to 2.5 parts of molding agent are pre-mixed. The method avoids the dispersing or grading sieving, and cobalt coating of the tungsten carbide; moreover, the prepared carbide alloy has good compactness, high strength and impact resistance, simple production process and no environment pollution.

A production method of an alumina multichannel ceramic membrane support belongs to the technical field of multichannel ceramic membranes. The production method of the alumina multichannel ceramic membrane support comprises the following steps: carrying out a plastic extrusion molding technology on alumina adopted as a main raw material, drying the molded material in a natural drying and microwave drying combination mode, and sintering the dried material in a shuttle kiln or a tunnel kiln. Rare earth oxide, nanometer alumina sol and a sintering aid are mixed, so the flexural strength and the acid and alkali corrosion resistance of the above obtained product are improved; introduction of an organic binder in the production process of an alumina multichannel ceramic membrane greatly reduces deformation of a green body in the extruding, drying and sintering processes and improves the yield of the product; and the nanometer alumina sol has high intergranular binding strength, so the granule morphology is kept, thereby the channels of the produced product are smooth and have small filtering resistance, and the water flux is improved by 20% or above.

The invention relates to a method for preparing a porous bone scaffold by laser and increasing mechanical and biological performances of the porous bone scaffold by adding zinc oxide with little amount, which belongs to the bone tissue engineering field. Aiming at uncontrollable performances of aperture distribution, shape, space direction and connectivity in the preparation method of a traditional bone scaffold, and aiming at the disadvantages of poor mechanical property and fast resolving rate existed in tricalcium phosphate (beta-TCP), the invention provides the method for preparing the porous bone scaffold by using a selective laser sintering (SLS) technology, and provides the method for increasing performance by adding zinc oxide (ZnO). The method for preparing the porous bone scaffold has the advantages that the porous scaffold which enables three-dimensional interconnection is prepared by SLS, zinc oxide with little amount is added for introducing into a liquid phase, the particles densification can be promoted, crystal grain is refined, and the mechanical performance is improved, simultaneously, cell compatibility is increased, the degradation rate is reduced, and the biological performance is increased, so that the interconnected porous beta-TCP bone scaffold with enhanced mechanical performance and good biological performance can be finally prepared. The method has the advantages of simple preparation technology, convenient operation, low cost, easy control of technical parameter and the like.

The invention relates to a silicon nitride material and a preparation method of a heat insulating disc cover prepared from the same. The silicon nitride material consists of the following raw materials in percentage by weight: 65-87.5 percent of silicon nitride, 5-15 percent of nano-silicon nitride, 8-15 percent of a sintering aid and 0.5-5 percent of tungsten carbide; and the preparation method of the heat insulating disc cover prepared from the silicon nitride material comprises the following steps of: weighing the silicon nitride, nano-silicon nitride, sintering aid and tungsten carbide according to the percentage by weight, performing ball milling and mixing uniformly; drying a mixed material to obtain a substrate; performing press molding to obtain a cylindrical biscuit; processing to a proper size on a lathe; putting the processed biscuit into a sintering furnace, and charging nitrogen gas for sintering; stopping heating, cooling, opening a furnace door under the normal pressure, and cooling naturally to obtain a blank; and performing end face processing on the blank on a grinding machine to obtain a finished product.

The invention relates to a preparation method of a special low-density grinding column for a cement grinding mill. The preparation method comprises the steps of with bauxite, alumina powder and the like as main raw materials and chromium oxide, zirconium oxide, calcium oxide, magnesium oxide, ferric oxide, manganese oxide, titanium oxide, silicon dioxide and the like as modified raw materials, adding alumina sol, silica sol and metal salt into slurry at a grinding stage; molding by rolling, isostatic pressing or machine pressing to obtain a green body; and calcining after drying the green body to obtain the low-density grinding column. By virtue of scientific proportion design, strict process control and unique calcining system, the special low-density grinding column disclosed by the invention is low in cost, excellent in wear resistance, lower in power load as comparison with a high-density metal grinding body, suitable for substituting a metal grinding body in cement grinding, iron ore grinding and gold ore grinding and capable of reducing the electric consumption for grinding by 30-50%.

The invention relates to a zirconia composite alumina ceramic sintered body. The zirconia composite alumina ceramic sintered body comprises the following components in percentage by mass: 0.01-19.0 wt% of a zirconium-containing compound (calculated in the form of zirconium oxide), 0.01-1 wt% of a yttrium-containing compound (calculated in the form of yttrium oxide), 0.16-4.6 wt% of a silicon-containing compound (calculated in the form of silicon oxide), 0.035-1.0 wt% of a calcium-containing compound (calculated in the form of calcium oxide), 0.07-2.0 wt% of a magnesium-containing compound (calculated in the form of magnesium oxide) and the balance of aluminum oxide. According to the zirconia composite alumina ceramic sintered body, 3Y-ZrO2 is taken as an additive, and the synergistic effect of multiple toughening modes such as phase change toughening, microcrack toughening, internal crystal structure strengthening toughening and surface strengthening toughening is achieved; CaCO3, SiO2and MgO are used as sintering aids, the sintering temperature of the aluminum oxide ceramic is reduced through liquid-phase sintering, the sintering rate is increased, sintering densification is promoted, and an aluminum oxide substrate prepared from the zirconia composite alumina ceramic sintered body has good fracture toughness and bending strength.

A process for preparing high-purity Ti-Al-C block by discharge plasma sintering includes such steps as proportionally mixing Ti3AlC2 powder or Ti powder, Al4C3 powder and active carbon powder, ball grinding, baking sieving, loading in graphite mould, discharging plasma sinter under protection of inertial gas, holding the temp for a certain time and cooling. Its advantages are high purity (90% or more) and high mechanical performance.

The present invention relates to an aluminum oxide-carbon titanium nitride-titanium-nickle composite material and the preparing method thereof, the volume percentage of the composite material combination is as follows: Al2O3:60-94, Ti(C, N): 5-35, Ti+Ni: 1-12; the preparation technique process comprises the following two steps of: a first step of raw material mixing and drying: (1) mixing the raw material Al2O3 powder, TiCN powder, ball-grinding medium and surfactant, ball grinding and drying; (2) mixing the raw material Ti powder, Ni powder and ball-grinding medium, and ball-grinding, the ratio of titanium and nickel atom is 1:1-1:4; (3) adding ball-grinding medium into the powder which is mixed and dried in the procedure (1) and (2), ball-grinding and drying, the adding amount of Ti and Ni powder is 1-12vol%, the second step is powder molding and sintering: the mixed powder processed in the procedure (3) is added into the hot pressing stove and is hot pressed for molding in the argon atmosphere, temperature of 1400-1700DGE C and pressure of 25-35MPa. The material of the invention has the following advantages: evident increased material combined properties of hardness, strength and toughness, and the material is more suitable for the cutter material used in the mechanical industry.

The invention relates to a low temperature fast preparation method of AlON crystalline ceramics, and belongs to the technical field of crystalline ceramic preparation. The preparation method provided by the invention applies ball-milling modification to AlON powder by adopting a planetary ball mill, the modified powder has tiny particles, and has the grain size distribution characteristics of single-modal, double-modal, multi-modal and the like, while possessing the characteristic of narrow molecular distribution, so as to be beneficial to improve the compactness of blank bodies and promote the sintered densification. The AlON powder which is manufactured through ball-milling modification and has the grain size distribution characteristics can be formed through preforming without adding binder, and further isostatic cool pressing is not required. The compactness of the blank bodies is high, and AlON crystalline ceramics with transmittance greater than 80% can be obtained through keeping the heat of the blank bodies at a temperature below 1900 DEG C with the effect of sintering agents. The preparation method has the advantages of low sintering temperature, short heat preservation time and good energy-saving effect; and the requirement for equipment is not high. The preparation method can be used for preparing construction members in abnormal shapes, so that the applied range is wide, the cost is low, the operation is simple and easy, and the industrialization is easy to realize.

The invention provides a method for preparing a bulk nano iron matrix composite by four-field coupling sintering. The four-field coupling adopted by the method refers to simultaneously applying rectangular pulse current and axial semi-wave pulse magnetic field and sintering pressure, wherein, the sintering pressure of positive and negative electrodes applied to power is 10MPa to 50MPa and time for sintering is 1 to 6 minutes. The peak value, base value, frequency, duty ratio of the rectangular pulse current and the strength of the additional axial semi-wave pulse magnetic field increase with the increasing of the size of sintering material. The method significantly improves the uniformity of the axial temperature field of sintering, promotes the comprehensive mechanical performance of iron matrix alloy in sintering state and prepares the bulk iron matrix composite that is characterized by being nearly completely compact, high strength and nanocrystal. The method obviously reduces the requirements for equipment, shortens period, improves efficiency, is especially beneficial to the domestic production of the bulk nano iron matrix composite and has good prospect of promotion and application.

The invention provides a preparation method of a boron carbide composite ceramic plate and a boron carbide titanium alloy composite bulletproof flashboard. The preparation method of the boron carbidecomposite ceramic plate comprises the steps of selecting boron carbide powder as a raw material, selecting a graphene material as a sintering aid, dispersing the graphene material by adopting a high-pressure homogenization process, then adding the boron carbide powder and the graphene suspension into a three-roll grinder for mixing, conducting granulating and drying to obtain granulated powder, filling the granulated powder into the graphite mold with a prefabricated shape, carrying out two-stage heating in a vacuum environment, introducing nitrogen while carrying out second-stage heating, carrying out heat preservation, quickly cooling to 2200 DEG C, and carrying out heat preservation for 1-1.5 hours. According to the preparation method of the boron carbide composite ceramic plate, sintering densification of boron carbide ceramic can be effectively promoted, overlarge growth of boron carbide ceramic grains can be avoided on the microcosmic level, and the fracture toughness of the boron carbide ceramic plate can be effectively improved.

The invention discloses a preparation method of a molybdenum-based alloy coating, and belongs to the field of preparation of alloy coatings. The method comprises the following steps of, 1, an iron base and a metal foil are taken, and pretreatment is carried out on the iron base and the metal so as to making the iron base and the metal foil reach the use requirements; 2, a graphite die is taken, and the graphite die comprises an upper pressure head, a lower pressure head and a hollow female die; and the iron base, the metal foil and molybdenum-containing metal powder are put into the female die successively, and the graphite die is pressed by the upper pressure head and the lower pressure head; and 3, the graphite die is placed into a hearth of a discharge plasma sintering system, the current is introduced, and sintering and bonding are carried out on the iron base and the molybdenum-containing metal powder. According to the preparation method, the problem that the thermal expansion coefficient between the coating and a base body is not consistent when a high-temperature coating is prepared on a low-melting-point base body is effectively solved, and the bonding strength is relatively high.

The invention discloses a preparation method of garnet with high power and high dielectric constant, which comprises the following steps: (1) burdening according to a chemical formula Y < 3-x-z-z '-y-2x'-z ''-p-q>Bi < x > Sm < z > Gd < z '> Ca < 2x' + y + z '' + p + q>Zr < y > Sn

Ti < q > Ge < z '> In<p'> V < x '> Mn < w > Al < w' > Fe < 5-x '-y-z' '-p-q-w-w'-delta-p >O < 12 >, wherein 0<=x<=1.3, 0<=x'<=0.70, 0<=y'<=0.70, 0<=z<=1.0, 0<=z'<=1.0, 0<=z''<=1.5, 0<=p<=0.50, 0<=q<=0.50, 0<=w<=1.30, 0<=p'<=0.50, 0<=w'<=0.10, and the iron deficiency delta is 0 <= delta<= 0.50; (2) primary ball milling; (3) drying, and pre-sintering in an oxidizing atmosphere for the first time; (4) secondary ball milling; (5) after drying, carrying out secondary pre-sintering in an oxidizing atmosphere; (6) carrying out third-time ball milling; (7) drying and granulating, primarily pressing granules into a blank, and then carrying out cold isostatic pressing; and (8) putting a formed blank into a furnace in an oxidizing atmosphere to be sintered at the sintering temperature from 900 DEG C to 1450 DEG C, and the heat preservation time from 30 hours to 100 hours. The high-magnetic-moment garnet material with relatively low delta H, relatively high delta Hk and a high dielectric constant epsilon' is obtained by promoting the solid-phase reaction degree, reducing the formation of a Bi-rich phase and utilizing rare earth ions Sm < 3 + > for substitution in the formula.

The invention discloses an in-situ growth beta-Si3N4 fiber/rod-like crystal enhanced glass-ceramic composite material and a preparation method thereof. The preparation method of the composite material comprises the steps that melt cooling and water quenching are carried out on La2O3, Y2O3, CaCO3, MgO, Li2CO3, Al2O3, SiO2 and other raw materials to prepare rare earth doped aluminosilicate glass powder, compression molding, drying and sintering are carried out on the glass powder and alpha-Si3N4 powder, and therefore the in-situ growth beta-Si3N4 fiber/rod-like crystal enhanced glass-ceramic composite material with the characteristics of being high in strength, low in coefficient of thermal expansion, high in heat conductivity and the like is obtained. The preparation technology is simple, low in sintering temperature, environmentally friendly and low in production cost. The obtained composite material has the wide application prospect, and can partially replace carbon/carbon, silicon carbide, carbon/silicon carbide, silicon nitride and other ceramic base high temperature structural materials to be used in the high-tech field of aerospace, aviation, national defense military industries, advanced manufacturing and the like.

The invention discloses high-performance powder metallurgy pressing sintering type semi-high-speed steel and a preparation method thereof. Preparation of the high-performance powder metallurgy semi-high-speed steel is achieved by adopting carbonyl iron powder and carbide powder as raw materials through the processes of ball-milling mixing, cold pressing forming, thermal degreasing, vacuum sintering and the like. The prepared semi-high-speed steel is uniform in chemical component, fine in grain and capable of achieving overall dispersion distribution of carbides, the problems such as componentsegregation and thick carbides existing in a traditional casting method are avoided, and the strength and the toughness of the material are significantly improved. The high-performance powder metallurgy pressing sintering type semi-high-speed steel has the advantages that the technological process is simple, the production cost is low, and the components are easy to control. Compared with semi-high-speed steel prepared through a casting method, the semi-high-speed steel has the advantage that the bending strength and the impact toughness are obviously improved at the same compactness.

The invention relates to a titanium calcium aluminate-silicon carbide complex phase refractory material and a preparation method thereof. The preparation method is characterized by taking 18 to 23 weight percent of alpha-Al2O3 powder, 5 to 10 weight percent of silicon micropowder and 1 to 3 weight percent of vanadium pentoxide are used as a first raw material; 55 to 60 weight percent of titanium calcium aluminate particles, 5 to 10 weight percent of silicon carbide particles and 4 to 6 weight percent of silicon carbide fine powder are used as a second raw material; the first raw material and the second raw material form raw materials; the second raw material, the first raw material subjected to ball grinding and an aluminum dihydrogen phosphate solution accounting for 3 to 4 weight percentof raw materials are subjected to mixing rolling, formation and drying; then, a dried blank body is put into an aluminum oxide sagger paved with crystalline flake graphite at the bottom; the crystalline flake graphite is used for filling and burying; heat insulation is performed for 3 to 4h under the condition of 1400 to 1450 DEG C; cooling is performed along with a furnace; the titanium calciumaluminate-silicon carbide complex phase refractory material is prepared. The characteristics of resource comprehensive utilization, energy saving and environment protection are realized; the preparedproduct has the advantages of high rupture strength, high compressive strength, low heat conductivity coefficient, excellent thermal shock resistant performance and good alkaline gas erosion resistantperformance.

The invention discloses a self-enhancement-toughening silicon nitride/ aluminum nitride/ lanthanum barium silicate glass ceramics ternary composite material with self-enhancement-toughening and a preparing method of the ternary composite material. The ternary composite material adopts lanthanum barium silicate glass powder, aluminum nitride powder and alpha-silicon nitride powder as raw materials, is prepared through blanking and sintering, and contains beta-silicon nitride rod-like crystal. The silicon nitride/ aluminum nitride/ lanthanum barium silicate glass ceramics ternary composite material has the advantages of being low in density, high in strength, high in fracture characteristic, high in dielectric constant, low in inflation coefficient, high in conductivity and the like. The preparing method of the ternary composite material is simple in preparing process and low in the glass melting temperature and the composite material sintering temperature, and the ternary composite material is friendly to environment and low in production cost. The prepared ternary composite material has a good application prospect, can partially replace an existing high temperature structure material, and is applied in the fields of national defense and military industries, electronic devices, high thermal conductivity ceramic baseplates, high-end ceramic parts and the like.