97 results about "Plasma activated sintering" patented technology

The invention relates to a method for quickly preparing a high-performance Mg2Si-based thermoelectric material. The method comprises the following steps: (1) weighing according to the stoichiometric proportion of all atoms in Mg2 (1+0.02) Si (1-x) Sbx (0<=x<=0.025), then grinding and uniformly mixing the atoms, and pressing the uniformly mixed powder into a block; (2) subjecting the block obtained in the step (1) to the self-propagating reaction, and then naturally cooling to obtain a single-phase Mg2 (1+0.02) Si (1-x) Sbx compound; (3) grinding the obtained product into powder, and performing discharge plasma activated sintering to obtain the high-performance Mg2Si-based thermoelectric material. The method provided by the invention has the advantages of quickness in reaction, simple process, high efficiency, energy saving, good repeatability and the like, the whole preparation process can be completed within 0.5 h, and the thermoelectric figure of merit ZT of the obtained block can reach 0.73 at 875K.

The invention provides a method for fast manufacturing n-type bismuth telluride based high-performance thermoelectric materials. The method specifically comprises the steps that 1), Bi powder, Te powder and Se powder are weighed according to the stoichiometric ratio of all elements in Bi2Te3-xSex, 0=<x<=3, and the Bi powder, the Te powder and the Se powder are evenly mixed and pressed to be blocks; 2), a self-propagating reaction is generated on the blocks in the step 1), cooling is carried out after the reaction is completed, and a single-phase Bi2Te3-xSex compound is obtained; 3), the single-phase Bi2Te3-xSex compound obtained in the step 2) is ground to be powder, then plasma activation sintering is carried out, and the high-performance Bi2Te3-xSex thermoelectric materials are obtained. The technology with self-propagating combustion synthesis combined with plasma activation sintering is adopted, the n-type bismuth telluride block thermoelectric materials with the thermoelectric optimal value zT reaching 0.95 within 426 K are manufactured within 20 min, and the advantages of being short in manufacturing time, simple in technology, high in thermoelectric performance of the materials and the like are achieved.

The invention provides a method for preparing high-performance Half-Heusler block thermoelectric materials at ultrahigh speed and low cost. The method particularly includes the steps that firstly, according to the general formula ABX of Half-Heusler compounds, powder A, powder B and powder X are weighed at the chemical stoichiometric ratio of 1:1:1, used as raw materials and uniformly mixed, and then an reactant is acquired; secondly, the reactant generates a combustion synthesis reaction, and cooling or quenching is conducted after the reaction is finished; thirdly, a product acquired through the second step is ground into fine powder, then PAS is conducted, and then the high-performance Half-Heusler block thermoelectric materials are acquired. According to the method, by the combination of the combustion synthesis reaction with the PAS process, the high-performance Half-Heusler block thermoelectric materials can be prepared within 15 min, and the method has the advantages that preparation time is short, energy consumption is low, the process is simple, the requirement for equipment is low, repeatability is good, and the method is suitable for large-scale production.

The invention relates to a high-performance Cu2SnSe3 thermoelectric material and a rapid preparing method thereof. The method includes the following steps that (1) Cu powders, Se powders and Sn powders are prepared as raw materials according to a stoichiometric ratio of 2.02: 3.03: 1, and then the Cu powders, the Se powders and the Sn powders are uniformly mixed to form a reactant; (2) self-propagating reaction of the reactant which is obtained in the step (1) is initiated, and naturally cooling is performed after the reaction is finished to obtain Cu2SnSe3 product; (3) the Cu2SnSe3 product obtained in the step (2) is ground to form fine powders, and then plasma activated sintering is performed to obtain the high-performance Cu2SnSe3 thermoelectric material. The high-performance Cu2SnSe3 thermoelectric material and the rapid preparing method thereof have the advantages that the reaction time is short, operation is simple and convenient, large devices are not required, noises are absent, and the performances of the product are 37.8% higher than those of products by traditional methods.

The invention relates to a new method for quickly preparing a high-performance PbS(1-x)Sex based thermoelectric material. The new method comprises the following steps of: 1) weighing Pb powder, S powder and Se powder as raw materials according to the stoichiometric ratio of all the atoms in PbS(1-x+y)Se(x+z), wherein x is greater than or equal to 0 and less than 1.0, y is equal to 0.02 and z is equal to 0; and when x is equal to 1.0, y is equal to 0 and z is equal to 0.02; next, grinding the powdery raw materials and mixing evenly, and then pressing into blocks; 2) arousing the self-propagating reaction of the blocks obtained in the step 1), naturally cooling after the reaction is completed, thereby obtaining a single-phase PbS(1-x)Sex solid solution; 3) grinding the PbS(1-x)Sex solid solution into powder, performing discharge plasma activated sintering to obtain the high-performance PbS(1-x)Sex based thermoelectric material. The new method provided by the invention has the advantages of high reaction speed, simple process, high efficiency and energy conservation, good repeatability and the like; the whole preparation process can be completed in 0.5 hour.

The invention discloses a method for quickly preparing an Ag2Se block thermoelectric material through self-homogenization for the first time. Ag powder and Se powder are used as raw materials; firstly the raw materials are easily mixed, and then the mixed raw materials are directly subjected to plasma activated sintering (PAS), so compact Ag2Se block thermoelectric material can be prepared in several minutes. The process dissolved by the method is super easy, the preparation time is super short, the obtained product is uniform in component distribution, and an obvious effect of self-homogenization is shown. The prepared Ag2Se block thermoelectric material is superior in performance, the room temperature ZT exceeds 0.6, and a good foundation is laid for large-scale preparation and large-scale application of the Ag2Se compound.

The invention is a method of preparing nano WC-Co hard alloy, preparing WC-Co mixed powder, making ball milling, finishing powder surface and making plasma activation and sintering to obtain nano WC-Co hard alloy. Its advantages: after finishing, the surface of Co powder is coated with a carbon film, improving surface structure, enhancing surface activity, beneficial to sintering powder, able to obviously shortening sintering time, and effectively controlling crystal particle growth, and the sintered product has fine crystal particles, high hardness and good flexibility. It is specially applied to preparation of nano WC-Co hard alloy.

The invention provides a high-performance Cu2Se block thermoelectric material with a nanopore structure and a rapid preparation method of the high-performance Cu2Se block thermoelectric material. The rapid preparation method includes specific steps of 1) preparing Cu powder and Se powder as raw materials according to a stoichiometric ratio of 2 to 1, and subsequently evenly mixing the Cu powder and the Se powder to obtain a reactant; 2) subjecting the reactant to a self-propagating reaction by means of a direct initiation or constant temperature initiation manner, and natural cooling after completion of reaction; 3) performing plasma activated sintering to obtain the high-performance Cu2Se block thermoelectric material with the nanopore structure. By means of self-propagating combustion synthesis combined with the plasma activated sintering process, the high-performance Cu2Se block thermoelectric material can be prepared within 20 minutes, a thermoelectric property optimum value of the high-performance Cu2Se block thermoelectric material reaches 1.9 at the temperature of 727 DEG C, the preparation time is short, the process is simple, the composition control is accuracy, the thermoelectric property of the material is high, the material is suitable for large-scale production, and a broad commercialization application prospect is achieved.

The invention discloses a method for preparing a Fe3Al-Al2O3 composite material. The method comprises the following steps of: (1) weighing 23 to 69 mass percent of Fe2O3 powder, 21 to 31 mass percent of Al powder and 0 to 57 mass percent of Fe powder and performing mechanical alloying; (2) controlling a mechanical alloying process, performing self-propagation reaction on the Fe2O3 powder and the Al powder to produce Al2O3 and Fe powder, wherein the Fe powder and the Al powder form Fe(Al) solid solution in the ball milling process so as to obtain a mixture of the Al2O3 and the Fe(Al) solid solution; and (3) filling the mechanically alloyed and ball-milled mixture of the Al2O3 and the Fe(Al) solid solution into a graphite mould, and performing plasma activated sintering to form the required blocky composite material. By the preparation method, the aplitic Fe3Al-Al2O3 composite material with 15 to 44 mass percent of Al2O3 can be obtained; and the method is a preparation method for mechanical alloying and plasma sintering of the Fe3Al-Al2O3 composite material, which has the advantages of short preparation process time, high product purity and compactness and low cost.

The invention relates to the field of diamond/copper-based composite materials and preparation technologies thereof, and specifically discloses a diamond/copper-based composite material and a preparation method thereof. Mass fraction of the diamond in the composite material is 20%-50%, and diamond particles are uniformly distributed in a matrix. The specific preparation method comprises the following steps: firstly, preparing copper-coated titanium-coated diamond composite powder; then, mixing the copper-coated titanium-coated diamond composite powder with copper powder to form mixed powder; and finally, preparing a sintering test sample with high compactness by surface activating and plasma activating and sintering. The plasma activating and sintering process is as follows: a heating rate is 50-200 DEG C/min, vacuum degree is not greater than 10Pa, pressure applied while sintering is 30-40 MPa, a sintering temperature is 800-900 DEG C, and a heat preserving time is 5-7 minutes. The prepared diamond/copper-based composite material is low in sintering temperature, high in compactness, fine in crystalline grain, simple to operate, and good in controllability.

The invention relates to a connecting method for a tungsten alloy and a molybdenum alloy. Specifically, an ultrathin copper film is deposited on each of the surfaces of the tungsten alloy and the molybdenum alloy or an ultrathin copper foil is added on each of the surfaces of the tungsten alloy and the molybdenum alloy, the plasma activated sintering connection technology is utilized, and the low-temperature and high-strength connection of the tungsten alloy and the molybdenum alloy is achieved under the technological conditions that the axial pressure ranges from 5 MPa to 30 MPa, the vacuum degree is smaller than or equal to 0.1 Pa, the activation time ranges from 20 s to 100 s, the temperature rise rate ranges from 80 DEG C/min to 200 DEG C/ min, and the temperature ranging from 650 DEG C to 850 DEG C is kept for 300 s-1,200 s. The connecting method has the beneficial effects that through introduction of ultrathin copper activated intermediate layers, the connecting temperature of the refractory metal tungsten alloy and the refractory metal molybdenum alloy is remarkably lowered, the connecting strength of the refractory metal tungsten alloy and the refractory metal molybdenum alloy is improved, low-temperature, rapid and high-strength connection of the tungsten alloy and the molybdenum alloy is achieved at the extremely low temperature for the first time, the shearing strength reaches 224.8 MPa, and compared with direct connection of the tungsten and the molybdenum, the strength is improved by near 7 times; and the connecting temperature is greatly reduced, and reliable connection of connecting connectors is improved.

The invention discloses a preparation method of a dual-scale titanium alloy material. The preparation method comprises the following steps that titanium alloy powder as the raw materials is subjected to low-temperature ball-milling, and fine-grain titanium alloy powder is obtained; the fine-grain titanium alloy powder and the titanium alloy powder as the raw materials are mixed, and the fine-grain titanium alloy powder in the mixed powder accounts for 5-95 wt%; and the mixed powder is subjected to degassing in a premade graphite mould, the degassed mixed powder is sequentially subjected to surface activation and discharge plasma activated sintering (PAS), and the dual-scale titanium alloy material is obtained. The production process is concise, short in period and high in structure controllability, and the compactness and mechanical property of the titanium alloy material can be effectively improved; and in the obtained dual-scale dual-phase titanium alloy material, dual-scale crystal grains are evenly distributed, the comprehensive mechanical performance is excellent, majority of industrial requirements are met, and the preparation method capable of achieving the industrially applied dual-scale titanium alloy material is provided.

The invention relates to a Sb doped BiCuSeO thermoelectric material and a preparation method thereof. The technical scheme is as follows: uniformly mixing bismuth oxide powder, copper powder, selenium granules, bismuth powder and antimony powder according to a mass ratio of 1: 3:3:(1-3Y): 3Y, wherein 3y is not smaller than 0.005 = x is not greater than 0.12, filling the mixture in a ball milling tank, ball milling in an inert gas atmosphere to prepare single-phase SbxBi1-xCuSeO powder, wherein x is not smaller than 0.005 and is not greater than 0.12, filling the single-phase SbxBi1-xCuSeO powder in a mold, placing the mold in a plasma activated sintering furnace, and heating up to 500-700 DEG C at a constant speed, boosting to 30-100MPa at a constant speed, cooling to the room temperature at a constant speed and reducing to the normal pressure at a constant speed, taking out the sintered mold, and demolding to obtain the Sb doped BiCuSeO thermoelectric material. The Sb doped BiCuSeO thermoelectric material has the advantages of simple process, short production cycle and high production efficiency. The products have the advantages of high purity, high density, low thermal conductivity, high power factor and high dimensionless thermoelectric merit value.

The invention belongs to the technical field of powder metallurgy, and particularly relates to a non-binding-phase carboloy metal and a preparation method thereof. The non-binding-phase carboloy metal comprises the following components in percentage by mass: 0.10-0.30% of vanadium carbide, 0.10-0.30% of tantalum carbide, 0.10-0.25% of cobalt, and the balance of tungsten carbide. According to the invention, a carboloy metal with high density, high hardness and high wear resistance is obtained by using a plasma activated sintering process, then a large-sized bulk material is obtained by using a special mould shape, and the process is simple, and low in cost, can be used for realizing mass production, and meets the requirements of hydro-jet sand mixing tubes on high-wear-resisting materials.

The invention discloses a method for quickly preparing a Sb2Te3 thermoelectric material. The method comprises the following steps that 1, Sb powder and Te powder are weighed according to the stoichiometric ratio of all elements in Sb2Te3 and then ground and mixed to be uniform to obtain a mixed raw material; 2, discharging plasma activated sintering is conducted on the mixed raw material obtained in the step 1, and the compact single-phase Sb2Te3 thermoelectric material is obtained. The antimony telluride thermoelectric material has the advantages of being high in reaction speed, efficient, economical in energy, good in repeatability and the like and has a very good application prospect.

The invention relates to a preparation method for a carbon fiber reinforced aluminum-based boron carbide neutron shielding material, belongs to the technical field of preparation and applications of carbon fiber reinforced metal-based composite shielding materials, and can solve the problem that the plastifying and processing performance of the composite materials are reduced by high ceramic particles in aluminum-based boron carbide. The preparation method comprises the following steps: filing a pre-prepared graphite mold with uniformly ball-milled and mixed composite powder for surface activation and plasma activated sintering; and carrying out thermal treatment on the sintered specimen to obtain the carbon fiber reinforced aluminum-based boron carbide composite material. The preparationmethod is an advanced method of carbon fiber reinforced aluminum-based boron carbide neutron absorption plate.

The invention relates to the field of ceramic material manufacture and discloses a processable complex-phase ceramic material and a preparation method thereof as well as a secondary hardening heat treatment method. The processable complex-phase ceramic material comprises the components of 40-80% of SiC, 5-30% of h-BN and 5-50% of Ti by weight. The preparation method comprises the steps of: preparing the components, carrying out ball-milling on the components to obtain mixed powder, and then sintering once in a plasma activated sintering (PAS) furnace to obtain a processable complex-phase ceramic material with relatively low hardness; and machining the prepared processable complex-phase ceramic material into a product, placing into a heat treatment furnace, and carrying out secondary hardening treatment in the presence of N2 gas shielding, therefore, the hardness of the product is enhanced and the application field of the product is enlarged.

The invention discloses a method for rapidly preparing a copper-molybdenum multi-layer composite material. The method comprises the following steps that (1) the surfaces of copper pieces and the surfaces of molybdenum pieces are polished so that oxidation films can be removed, the polished copper pieces and the polished molybdenum pieces are washed through acetone, and the processed copper pieces and the processed molybdenum pieces are dried by cold air for later use; (2) the copper pieces and the molybdenum pieces are overlaid in an alternating mode so that a multi-layer structural plate can be formed and the multi-layer structural plate is placed in a combination mold; (3) the combination mold containing the multi-layer structural plate is placed in a plasma activation sintering furnace, demolding is conducted after sintering is conducted, and therefore the copper-molybdenum multi-layer composite material is obtained. Electrifying, heating and sintering are directly conducted on the multi-layer structural plate obtained by overlaying the copper pieces and the molybdenum pieces in the alternating mode by introducing a high-density current, rapid diffusion bonding of copper-molybdenum interfaces is achieved under the combination action of temperature and pressure, the copper-molybdenum multi-layer composite material prepared with the method is good in heat conductivity and thermal expansion coefficient, the bonding strength of the copper-molybdenum interfaces is high, the product consistency is good, and punch forming can be achieved.

The invention relates to a new method for synthesis of a super fast prepared high performance CoSb3-based thermoelectric material by self-propagating combustion. The new method comprises the following steps: 1) weighing Co powder, M powder, Sb powder and Te powder as raw materials according to stoichiometric ratio of each element in the chemical formula Co4-xMxSb12-yTey, wherein 0<= x <=1.0, 0<= y <=1.0, M is Fe or Ni, the raw material powder is mixed and pressed into a bulk blank body; 2) triggering high temperature self-propagating synthesis reaction of the bulk blank body obtained by the step 1), and after the reaction cooling to obtain a single phase CoSb3 compound; 3) grinding the product of the step 2) into powder for discharge plasma activated sintering to obtain the pure single phase high performance CoSb3-based thermoelectric material. The method has the advantages of fast reaction speed, simple process, high efficiency, energy conservation, good repeatability, and the like. The whole preparation process can be completed in 20min, and the bulk thermoelectric figure of merit (ZT) is 0.98 at 875K.

The invention discloses a preparation process of pure Fe3C blocks. The preparation process comprises the following steps: firstly, weighing reducing Fe powder and amorphous C powder in a weight ratio converted from the atomic ratio and the atomic weights of various elements in the molecular formula Fe3C, putting the weighed materials into a ball milling jaw, and meanwhile, adding a certain amount of phenolic resin and vacuumizing; secondly, putting the ball milling jar into a ball mill for ball milling for 60-120 hours, taking the mixture of the reducing Fe powder and the amorphous C powder and arranging the mixture into a graphite crucible; finally, putting the graphite crucible into a plasma activating sintering furnace for two stages of vacuum sintering, namely slow pressureless sintering at a temperature ranging from 150 to 300 DEG C at the first stage and fast pressure sintering at a temperature ranging from 500 to 700 DEG C at the second stage, and cooling along with the furnace, thereby obtaining the pure Fe3C blocks.

The invention relates to a Fe-doped BiCuSeO thermoelectric material and a preparation method thereof. The preparation method is characterized by comprising the steps of: preparing materials accordingto an amount-of-substance ratio of bismuth oxide powder to copper powder to selenium powder: bismuth powder to iron powder being 1:3:3:(1-3y):3y, wherein 0.01<=3y = x <=0.08, mixing the powder, putting the mixed powder into a ball-milling tank, performing ball milling on the mixed powder under the condition of an inert atmosphere to prepare single-phase FexBi1-XCuSeO powder, putting the single-phase FexBi1-XCuSeO powder into a mold, placing the mold in a plasma activated sintering furnace, raising the temperature to 500-700 DEG C at a constant speed and raising the pressure to 30-100 MPa at aconstant speed simultaneously, maintaining the temperature and pressure simultaneously, then reducing the temperature to normal temperature at a constant speed and reducing the pressure to normal pressure at a constant speed simultaneously, taking out the sintered mold, and demolding to obtain the Fe-doped BiCuSeO thermoelectric material. The preparation method has the advantages of simple process, short production cycle and high production efficiency. The prepared product has the advantages of high purity, low thermal conductivity, high electrical conductivity, good electrical transmission performance, high power factor and high dimensionless thermoelectric figure of merit ZT.

The invention provides a method for preparing a high-strength micro porous metallic titanium block by dealloying a titanium-molybdenum alloy. The method is characterized in that the titanium-molybdenum alloy is treated through plasma activated sintering, molybdenum in the alloy is corroded selectively in a dealloying manner, obtained porous titanium is subjected to deoxidation and secondary sintering by the combination with a molten salt electrolysis method, so that the purity and the mechanical performance of a porous titanium block are greatly improved, and the high-strength porous titaniumblock is obtained. A titanium-molybdenum bicontinuous three-dimensional network-structured titanium-molybdenum alloy is prepared through plasma activated sintering; the pore structure of the porous metallic titanium block is regulated and controlled by changing the content of titanium and molybdenum elements; the obtained porous titanium is subjected to deoxidation and secondary sintering by adopting the molten salt electrolysis method, so that the purity and the mechanical performance of the porous titanium block are greatly improved; the high-strength porous titanium block of which the aperture is 5-10 [mu]m, the porosity is 78.5%-44.6%, and the compressive strength can reach 152.3 MPa can be obtained by adopting the process; and the method has the advantages of simple process, low cost,high practicability and the like.