117results about How to "Sintering process is simple" patented technology

The invention discloses a bismuth ferrite-based leadless piezoelectric ceramic with high Curie temperature and a preparation method thereof. The general formula for the piezoelectric ceramic is (1-x-y)(BizM1-z)t(FeuM'1-u)O3-xBaTiO3-yBiMnO3, wherein, M is a trivalent metallic element with large ionic radius, M' is a trivalent metallic element with small ionic radius, and x, y, u, t and z represent mole content in a ceramic system and satisfy the following relations: 0<=x<=1.0, 0<=y<=0.1, 0<z<1, 0.85<t<1.2, 0<u<1 and x+y<1. The piezoelectric ceramic is prepared by a conventional ceramic preparation method through selection of proper technological parameters. The piezoelectric constant d33 of the ceramic can reach 140 pC/N, Curie temperature can reach 490 DEG C, and Kt is more than 0.50. The preparation method has the advantages of a simple and stable process, and obtained leadless piezoelectric ceramic has excellent performance and is suitable for being used under high temperature.

The invention relates to a composite high-temperature molybdenum disilicide-base material and a preparation method thereof. The method can prepare the composite high-temperature material under lower production cost, which has the highest room temperature toughness equivalent to that of high-temperature alloys, higher high temperature intensity, high temperature creep resistant performance and certain plastic processing performance; the substrate of the composite high-temperature material is a composite substrate composed of MoSi2 and Si3N4, wherein the average crystal grain size of the MoSi2 is smaller than 2 microns, and the average grain diameter of the Si3N4 particulates is smaller than 1 microns. The method adopts the following technical proposal: Mo2N powder or powder of Mo5Si3 or Mo3Si are used as initial powder to obtain composite powder Mo3Si-Mo5Si3-Si3N4 or Mo5Si3-MoSi2-Si3N4 after being processed by siliconization or nitridation-siliconization, the composite powder is further enhanced and mixed with materials such as Si powder, SiC powder and the like, and is pressing molded, and then a blank is sintered under the temperature of 1415 to 1550 DEG C, and finally the sintered blank is plastic deformed, thus obtaining a required dense article of the composite high-temperature material.

The invention discloses a transition metal diboride high-entropy ceramic and a preparation method thereof, mainly relates to a high-entropy ceramic material with excellent performance, and belongs tothe field of high-temperature ceramics. At least five IVB, VB and VIB groups of transition metal boride powder is mixed according to the same mole ratio, high-energy ball milling and vacuum treatmentof mixture are implemented, the mixture is packaged and pre-pressed by high-melting-point packaging material, and the packaged mixture is sintered at the pressure of 4-10GPa and at the temperature of1000-1800 DEG C to form the diboride high-entropy ceramic. The diboride high-entropy ceramic is firstly prepared by a high-temperature and high-pressure method and has the advantages of high breakingtenacity, compactness and hardness, small grain size, excellent oxidation resistance and the like. the method has the advantages that the method is low in cost, environmentally friendly, simple in sintering process, good in product performance and high in finished product ratio, and raw materials are easily acquired. Industrial production is facilitated.

The invention relates to a process for preparing gradient cemented carbide with a cubic carbide free layer, which is generally used for preparing a coated cemented carbide substrate. The process is characterized in that: an initial component adopts a nitrogen-free cemented carbide raw material, and is prepared into a blade or a sample green compact by a standard cemented carbide preparation process; and a sintering process adopts a one-step sintering method comprising the following steps of: performing sintering by adopting normal dewaxing and deoxidizing processes, introducing micro-pressure nitrogen to react the nitrogen with carbides in the cemented carbide substrate to synthesize a nitrogen-containing cubic phase, evacuating the nitrogen at gradient sintering temperature and switching to sintering in a denitriding atmosphere like vacuum to form a surface layer into a cubic phase-free and cobalt layer-rich structure, namely, the cubic carbide free layer. The process is characterized in that: a nitrogen-containing phase is not added into the cemented carbide raw material, so the increasing of alloy porosity caused by the early decomposition of the nitrogen-containing phase can be avoided; the reaction nitrogen-addition of the cemented carbide substrate is realized by controlling the reaction between the sintering atmosphere and the cemented carbide substrate, so the gradient cemented carbide with the cubic carbide free layer also can be prepared under the condition of not adding the nitrogen-containing phase into the initial component; due to the adoption of the one-step sintering method, the sintering process can be simplified and the production cost can be reduced; and the prepared gradient cemented carbide comprises the cubic carbide free layer with the thickness of 10 to 40 microns, and has high compactness and bending resistance.

This invention provides a sintering method for a high-saturated flux density MnZn ferrite including the following steps: a, a first temperature-rising stage, b, a second temperature-rising stage, c, a heat preservation stage, d, temperature-reducing, which can increase the saturated flux density of MnZn ferrite greatly by controlling the temperature and oxygen partial pressure during the sintering process, besides, no expensive asistant components are needed in the preparation process.

The invention relates to a functionally graded material shape (1) where a first material (M1) is fused with a second material (M2) through sintering and a method of production of said functionally graded material shape (1). Said first material (M1) has a first coefficient of thermal expansion (α1) and said second material (M2) has a second coefficient of thermal expansion (α2), differing from the first coefficient of thermal expansion (α1). The invention is characterized in that the shape (1) further comprises a third material (M3) adapted to, together with M1 and M2, create an intermediate composite material phase intermixed between the first and the second materials (M1, M2). Said third material (M3) has a coefficient of thermal expansion (α3) intermediate between the first coefficient of thermal expansion (α1) of the first material (M1) and the second coefficient of thermal expansion (α2) of the second material (M2).

The invention discloses a preparation method of a diamond/copper composite high in heat conduction performance. The preparation method comprises the following steps of 1, uniformly mixing diamond obtained after surface of the diamond is subjected to degreasing and roughening treatment with tungsten powder according to the mass ratio of 1: 4.5, heating a powder mixture under the vacuum condition, conducting heat preservation for 2-8 hours at the temperature of 1030 DEG C, and finally, separating out modified tungsten-plated diamond, wherein the vacuum degree is 10<-2>-10<-4> Pa, and the temperature rising rate is 5 DEG C/min; and 2, uniformly mixing the tungsten-plated diamond, with the mean particle size being 125 microns, obtained after surface modification with copper powder with the mean particle size being 45 microns with the total volume content of the tungsten-plated diamond accounting for 55%, sintering an obtained powder mixture, and then cooling the obtained power mixture to the room temperature, so that the diamond/copper composite is obtained, wherein the sintering parameters are that the pressing pressure is 40 MPa, the temperature is 1000 DEG C, the temperature risingrate is 100 DEG C/min, the sintering time is 10 minutes, and the atmosphere is vacuum.

The invention relates to a preparation method of Y2O3-MgO nano complex-phase infrared transparent ceramic. The preparation method comprises the following steps: firstly pressing Y2O3-MgO complex-phasenano-powder into a biscuit, carrying out a two-step sintering process in a muffle furnace in an air atmosphere to obtain a ceramic blank and then carrying out hot isostatic pressing sintering to obtain the infrared transparent Y2O3-MgO nanovcomplex-phase ceramic. The density is close to the theoretical density, the grain size is small, the average transmittance (thickness is 2.0 mm) of mid-infrared 3-6 microns is greater than 76% so as to be superior to that of a sample prepared through conventional auxiliary hot isostatic pressing sintering after sintering.

The invention discloses a cylinder block assembly inlaid with a copper bush. The cylinder block assembly comprises a cylinder block, wherein a sintered layer is arranged on the matching surface of the cylinder block and a port plate; an axle hole is formed in the middle of the cylinder block; a hole groove is formed in one side of the axle hole in the cylinder block; the copper bush is arranged in the hole groove; and the cylinder block is machined from steel parts. The process route of the cylinder block assembly disclosed by the invention comprises rough turning, sintering, finish turning, spline drawing, copper bush press-fit, radial facing, nitrogen treatment and copper bush fine boring. The cylinder block assembly disclosed by the invention is easy to machine and produce, and capable of decreasing production cost; a sintering process for the cylinder block is simple; and the sintered layer is not liable to fall off.

The invention discloses a preparation method of a solid oxide fuel cell gradient porous structure cathode film and belongs to the technical field of electrode design and preparation. A solid oxide fuel cell cathode is subjected to a gradient design and is divided into an inner layer, a middle layer and an outer layer; and the cathode film with the gradient-changeable grain diameter, gradient-changeable air pore size and gradient-changeable porosity is prepared by adopting a laminating tape casting process. The preparation method is simple and low in cost; and a prepared single cell has a good electrochemical performance and is expected to be applied and developed in commercialized production in middle-temperature and low-temperature flat plate type solid oxide fuel cells.

The invention relates to a method for preparing a high-flatness tungsten-nickel-iron alloy plate. The method comprises the following steps of pressing granulated and dried tungsten-nickel-iron alloy powder, and rolling the tungsten-nickel-iron alloy powder to obtain a tungsten-nickel-iron alloy green body with a thickness of 0.5 to 1.8mm and uniform density; placing the obtained tungsten-nickel-iron alloy green body into a sintering furnace, sintering the tungsten-nickel-iron alloy green body under the protection of hydrogen, and cold-rolling the sintered tungsten-nickel-iron alloy green body until the deformation reaches 40 percent; re-sintering the cold-rolled tungsten-nickel-iron alloy green body for 1 to 3 hours at the re-sintering temperature of 1,100 to 1,300 DEG C under the protection of hydrogen; repeating the former two steps until the thickness of the green body is smaller than 0.4mm; overlaying two tungsten-nickel-iron alloy plates with the thickness of 0.15mm, and rolling-milling the tungsten-nickel-iron alloy plates for about 25 times under the pressure of about 15T until the thickness of a single plate is less than 0.1mm. According to the method, a production process is simplified, the energy consumption is lowered, the production cost is reduced, and green production is ensured.

The invention relates to low-temperature liquid-phase sintered La2Zr2O7 ceramics comprising 97 to 99.5 percent of La2Zr2O7 and 0.5 to 3 percent of CuO-TiO2 by percent weight. A preparation method of the low-temperature liquid-phase sintered La2Zr2O7 ceramics comprises three steps of proportioning/mixing, pressing and sintering. According to the low-temperature liquid-phase sintered La2Zr2O7 ceramics and the preparation method of the low-temperature liquid-phase sintered La2Zr2O7 ceramics, La2Zr2O7 ceramics is obtained by using common normal-pressure sintering through introducing a binary sintering adjuvant of the CuO-TiO2 into the La2Zr2O7; a liquid phase is formed at low temperature by utilizing the CuO-TiO2 through regulating the content of the CuO-TiO2 and controlling a sintering process, so that an La2Zr2O7 sintering mechanism is converted from solid-phase sintering to liquid-phase sintering; therefore, the sintering temperature is greatly lowered; and a compact La2Zr2O7 ceramic block body is obtained at about 1100 DEG C, the prepared ceramics has smaller crystal grains, the mechanical property is good, and the energy consumption is low. According to the low-temperature liquid-phase sintered La2Zr2O7 ceramics and the preparation method of the low-temperature liquid-phase sintered La2Zr2O7 ceramics, the components are reasonable, the preparation process is simple, the sintering temperature is low, and the La2Zr2O7 crystal grains prepared by sintering are fine and compact; and the preparation of a ceramic material of an La2Zr2O7 thermal barrier coating or an La2Zr2O7 block body at low temperature can be realized. The low-temperature liquid-phase sintered La2Zr2O7 ceramics and the preparation method of the low-temperature liquid-phase sintered La2Zr2O7 ceramics are suitable for industrialized application.

The invention relates to a preparation method for Ti2SnC reinforced Ag-based electrical contact materials. The composite materials are composed of Ti2SnC and an Ag base body, wherein the mass percentage of the Ti2SnC reinforcement phase is 1-50%. The Ti2SnC powder and Ag powder are mixed for 5-240 min at a ratio, and then subjected to cold press molding under the pressure of 100-800 MPa. A green body is sintered for 1-12 h at 600-1000 DEG C in a protection atmosphere or vacuum, and then the Ti2SnC reinforced Ag-based composite electrical contact materials are obtained. The Ag/Ti2SnC composite electrical contact materials prepared through the method have the advantages of being high in density, uniform in structure, moderate in hardness, good in electrical conductivity and the like.

The invention relates to a method used for preparing a AgSbTe2 thermoelectric material. The method comprises following steps: 1) material preparation, wherein silver telluride and antimony telluride are taken as main raw materials, trace elemental tellurium is taken as a thermoelectric performance regulating composition, and silver telluride, antimony telluride, and elemental tellurium are weighed at a molar ratio of (0.9-1.1)(0.9-1.1):x as reaction raw materials, and x ranges from 0 to 0.04; 2) high energy ball milling, wherein the raw materials disclosed in step 1) are subjected to high energy ball milling in inert gas protection atmosphere so as to obtain single-phase AgSbTe2 powder; and 3) spark plasma sintering, wherein the single-phase AgSbTe2 powder is subjected to spark plasma sintering so as to obtain the compact AgSbTe2 thermoelectric material. The raw materials are stable in the air; oxidation is not easily caused; the whole technology is simple and controllable; preparation cost is low; repeatability is high; density of the prepared AgSbTe2 block material is high; phase is pure; and thermoelectric performance is excellent.