451results about How to "Low melting point" patented technology

The invention discloses a high-strength silver-free copper-based brazing filler metal which is composed of P, Sn, Ni and Cu. The high-strength silver-free copper-based brazing filler metal is low in cost, safe, environmentally friendly and good in welding effect; through the adding of Sn and Ni, the melting point of brazing filler metal alloy is reduced, and the tensile strength and wettability of the brazing filler metal alloy are enhanced.

The invention provides a method for preparing a ceramic bond through solution heat preservation and a superhard grinding tool. The ceramic bonding agent prepared through a solution heat preservation method is fine in powder granularity and low in sintering temperature and contains a certain amount of crystals, the bonding agent has high impact resistance and self-sharpening performance due to existence of the crystals, and the prepared superhard ceramic grinding tool has the performance of high strength and good sharpness. The method has the advantages of short binding agent preparation period, low equipment investment cost, simplicity in operation and the like. The preparation method of the ceramic bond provided by the invention is not reported.

The invention relates to the field of building materials, and particularly discloses a coal gangue activation treatment method, prepared calcined coal gangue and application, the treatment method comprises the following steps: pretreatment: crushing and screening coal gangue to obtain coal gangue particles; the coal gangue particles are treated in a eutectic solvent, ultrasonic-assisted treatment is carried out for 2-3 h, pretreated coal gangue is obtained after water washing, the eutectic solvent comprises an HBA component and an HBD component, the HBA component is a mixture of choline chloride and an amide compound, and the HBD component is a mixture of a carboxylic acid mixture and polyhydric alcohol; calcining: calcining the pretreated coal gangue at 400-450 DEG C to obtain calcined coal gangue, the invention also discloses the calcined coal gangue prepared by the method, and the method has the characteristic of realizing coal gangue activation treatment under lower energy consumption.

The invention discloses an arylamine compound, a composition containing the arylamine compound and an organic light-emitting device. The structure of the arylamine compound is as shown in the following formula (1): # imgabs0 # formula (1). Wherein ring A is selected from substituted or unsubstituted phenanthrene ring; b is selected from structural substituents as shown in the following formula (2); # imgabs 1 # formula (2). And ring C is selected from a substituted or unsubstituted benzene ring, a substituted or unsubstituted naphthalene ring and a substituted or unsubstituted phenanthrene ring. The arylamine compound provided by the invention has a series of excellent physical and chemical characteristics, and has a good application prospect in the photoelectric field. Specifically, the arylamine compound has excellent photoelectric stability, can effectively resist performance degradation caused by illumination and current change, and ensures stable output of the device in long-time operation. The light-emitting diode has the advantages of low sublimation temperature, low driving voltage, high light-emitting efficiency and long device service life.

The invention relates to a perfluoro wide-temperature electrolyte for a lithium battery and application thereof, the wide-temperature electrolyte comprises a lithium salt, an additive and a plurality of perfluoro mixed solvents, the electrolyte capable of stably working in a wide temperature range (-80-80 DEG C) is successfully constructed, and the excellent electrochemical performance of the lithium battery at the wide temperature is realized. The electrolyte additive disclosed by the invention mainly comprises one or more of hexafluoroisopropoxy cyclotriphosphazene, 3-(2, 2, 2-trifluoroethoxy) propionitrile, 3-(2, 2, 2-trifluoroethoxy) butyronitrile, 3, 4-fluoroethylene sulfate and 4-trifluoromethyl-ethylene sulfate, and the fluorine-containing additive is good in flame retardant effect, moderate in viscosity, good in system compatibility, good in corrosion resistance and good in corrosion resistance. And a protective film can be formed on the surface of the positive electrode of the lithium battery, so that the high-pressure and high-temperature cycle performance of the battery is improved, the electrochemical performance of the battery is not influenced at all, the self-extinguishing time of the electrolyte is obviously shortened, the flame retardant property and the conductivity are excellent, the overcharge resistance of the lithium ion battery is also obviously improved, and the safety performance of the battery is improved.

The invention relates to a solid electrolyte, a composite positive electrode, a preparation method of the composite positive electrode and an ultra-fast charging type all-solid-state battery, and belongs to the technical field of solid-state batteries. The formula 1 is Li < x > Al < alpha > M < beta > X < y > O < z >, X is halogen, M is a trivalent element except Al, the ratio of x to (alpha + beta) is (1-5): 1, the ratio of alpha to (alpha + beta) is (0.5-1), and the ratio of x to z is (1.25-5). The solid electrolyte provided by the invention is low in glass transition temperature and melting point, has viscoelasticity and relatively high ionic conductivity, and can be fused and cast together with a positive electrode material to form a composite positive electrode at a relatively low temperature, and relatively good interface contact (surface-to-surface contact) can be formed between the positive electrode and the solid electrolyte only by applying relatively small external force; according to the all-solid-state battery, the problem that rigid contact between the solid electrolyte and the positive electrode in the existing all-solid-state battery causes poor ion transmission network and further affects the battery performance is solved, the ion transmission efficiency and the charge-discharge rate performance of the solid-state battery are improved, and rapid and ultrafast charging can be realized.

The recovery method of the laterite-nickel ore leaching residues comprises the following steps that S1, in the presence of a first reducing agent, the laterite-nickel ore leaching residues are roasted, and roasted sand and sulfur-containing tail gas are obtained; s2, in the presence of a second reducing agent, smelting the roasted product obtained in the step S1 to obtain molten iron, smelting slag and coal gas; the laterite-nickel ore leaching residues are in a dry state; the smelting slag is a MgO-Al2O3-SiO2-FeO slag system, and the smelting slag is a MgO-Al2O3-SiO2 The ratio of the total mass of fixed carbon in the first reducing agent to the total mass of sulfur in the laterite-nickel ore leaching residues is 0.35-0.50. According to the recycling method, iron and sulfur in the laterite-nickel ore leaching residues can be comprehensively recycled under the condition that extra flux is not needed, resource utilization of the laterite-nickel ore high-pressure leaching residues is achieved under the condition that the overall process cost is low, and large-scale industrial use is facilitated.

The invention relates to the technical field of electroslag remelting slag. The invention discloses a special slag system for an ingot pulling type electroslag remelting nitrogen-controlled austenitic stainless steel ingot, which comprises the following components in percentage by mass: 45-50% of CaF2, 25-30% of Al2O3, 15-20% of CaO, 3-6% of MgO, 5-10% of SiO2 and the balance of impurities, and the content of the impurities is less than or equal to 1%. The binary alkalinity CaO / SiO2 is 1.5 to 4; the melting point of the special slag system is 1250-1280 DEG C, the viscosity value of the special slag system at the temperature of 1600 DEG C is 0.044-0.053 Pa.s, and the resistivity of the special slag system at the temperature of 1600 DEG C is 0.51-0.55 omega.cm. According to the slag system, by optimizing the components of the slag system, the physical and chemical properties of the slag system are further improved, the slag-metal reaction is inhibited, and the production process requirements of ingot pulling type electroslag remelting large stainless steel ingots are met. The produced nitrogen-controlled austenitic stainless steel ingot is good in surface quality and free of defects such as obvious pits, slag runners and double skins; and easily oxidized elements Al and Si in the steel in the remelting process are uniformly distributed in the height direction of the cast ingot, so that the uniformity of alloy textures is ensured.

The invention discloses a high-temperature-resistant liquid crystal polyarylester and a preparation method thereof, the liquid crystal polyarylester is formed by polymerizing monomers, and the monomers are composed of p-hydroxybenzoic acid HBA, 4, 4 '-biphenol BP, terephthalic acid TA, 2, 6-naphthalic acid NDA and 9, 9-bis [4-(4-methoxycarbonyl phenoxy) phenyl] fluorene; the corresponding molar ratio of the monomers is (50-60): (20-25): (5-10): (10-15): (1-5), and the sum of the molar ratios of the monomers is 100. By adding a small amount of 2, 6-naphthalic acid, the melting point Tm of LCP is reduced, the processing temperature window is widened, and processing is facilitated; by adding a small amount of bisphenol fluorene containing ether bonds, the toughness and processability of the LCP are improved while the glass-transition temperature Tg of the LCP is improved.

The invention discloses a method for manufacturing a high-wear-resistant composite swing hammer head, which comprises the following steps: washing and drying ceramic particles with an oxalic acid solution, uniformly mixing boron carbide ceramic powder and an alcohol adhesive in proportion into a slurry, and drying to remove the alcohol adhesive; then mixing the ceramic particles with NiCrBSi powder and a sodium silicate solution and filling the mixture into a honeycomb mold, taking the mixture out after microwave curing, thereby obtaining a honeycomb ceramic preform with high strength at room temperature, wherein a conical preformed hole is formed on the honeycomb ceramic preform, placing the honeycomb ceramic preform into a casting cavity of a swing hammer head metal mold, and then pouring molten high-chromium cast iron into a runner of the casting mold, wherein the high-chromium cast iron water infiltrates into gaps between ceramic preform particles under high pressure to form a reactive interface, thereby obtaining a high-wear-resistant composite swing hammer head. The method can manufacture a composite swing hammer head with a reactive interface and high wear resistance.

The invention belongs to the technical field of ferrous metallurgy steelmaking, and particularly relates to a system and method for preventing surface recarburization of a continuous casting high-pulling-speed casting blank and a steel plate. Comprising an amplitude difference control module, a liquid slag layer adjusting module and a casting powder adding module. The amplitude difference control module is used for controlling the liquid level fluctuation amplitude difference of the crystallizer to be within a preset value; the liquid slag layer adjusting module is used for adjusting the thickness of a liquid slag layer in the casting powder to reach a set value; the covering slag adding module is used for adding covering slag to the edge of the crystallizer. According to the method, the liquid level fluctuation amplitude difference of the crystallizer and the thickness of the liquid slag layer are controlled within a certain range, meanwhile, the slag adding mode of the casting powder in the production process is reasonably adjusted, and therefore the problem that molten steel makes contact with a carbon-rich layer on the top of the liquid slag layer is effectively solved, and the production cost is reduced on the premise that continuous casting high-pulling-speed production is not affected. And recarburization on the surface layer of the casting blank can be prevented.

The invention belongs to the technical field of textile production, and relates to an active disperse dye and a dyeing process. The reactive disperse dye comprises a dye matrix and a bis-aziridine chain segment grafted on the dye matrix, and-OCH2-is introduced to an aromatic ring para-position of the bis-aziridine chain segment as an electron-donating group. A dyeing process: after active disperse dye is dissolved, dyeing the textile; the textile consists of more than one of natural fibers and synthetic fibers; the dyeing temperature is 85-100 DEG C, and the dyeing temperature is higher than Tg of the synthetic fibers. According to the invention, a '-OCH2-' electron-donating group is introduced in the para-position of an aromatic ring of a diaziridine chain segment, and the conjugation effect and the induction effect of the group reduce the activation energy of C-N bond breakage, so that carbene can be efficiently generated without depending on a high-temperature or acid-base environment; the problems that in the prior art, the condition for generating carbene through a diaziridine chain segment is harsh, and the color fastness of the dyed textile is low when supercritical CO2 fluid is adopted for dyeing are solved.

The invention discloses high-crystallinity copolyester based on furandicarboxylic acid as well as a preparation method and application of the high-crystallinity copolyester. The structural formula of the high-crystallinity copolyester is as follows: # imgabs0 # R1 is-O (CH2) aO-, R2 is-O (CH2) bO-, a, b, x, y, z and n are integers, a = 2-6, b = 6-12, x = 1-10, y = 1-10, z = 1-10, and n = 20-100; and (x + z): y = 1: 1-1: 10. The present invention also provides a highly crystalline copolyester article made from the highly crystalline copolyester. The high-crystallinity copolyester disclosed by the invention not only has excellent crystallization capacity, relatively high crystallinity, excellent thermal stability and mechanical property, but also has excellent barrier property, and has obvious advantages in various gas barrier aspects compared with PET (Polyethylene Terephthalate) on the market; the material can be widely applied to the fields of high-temperature-resistant materials, express packages, food packages, food tableware and the like.

The utility model relates to a battery shell, a battery, a battery pack and a power utilization system, the battery and the battery pack shell form the battery pack for supplying power to the power utilization system, and the battery shell of the battery comprises a shell body and a cover plate. Wherein the shell comprises an inner cavity, the inner cavity is provided with an opening, the cover plate is fixed on the shell, and the cover plate shields the opening of the inner cavity. At least one of the surface, facing the shell, of the cover plate and the surface, facing the cover plate, of the shell is provided with a first groove, a brazing seam is arranged between the cover plate and the shell, and the brazing seam is used for fixedly connecting the shell and the cover plate and sealing the inner cavity. The first groove is suitable for containing welding flux used for forming a brazing seam. The battery shell provided by the utility model adopts brazing, so that the welding difficulty is reduced, the manufacturing cost is reduced, and the residual stress and failure risk after welding are reduced.

The invention discloses a low-temperature electrolyte as well as a preparation method and application thereof, belongs to the technical field of battery electrolytes, and solves the problem of non-ideal battery performance in a low-temperature environment due to non-ideal compatibility of linear carboxylic ester and nitrile solvents and graphite in a lithium ion battery electrolyte in the prior art. The low-temperature electrolyte disclosed by the invention comprises the following components: electrolyte solute lithium salt, an organic solvent, an electrolyte additive and 3-fluorotoluene, wherein the organic solvent is a mixture of linear carboxylic ester and nitriles in a volume ratio of 1: (0.25-4). According to the electrolyte provided by the invention, the reversible charge-discharge performance of the lithium ion battery in a low-temperature environment is effectively improved.

The invention discloses a thermal deformation neodymium-iron-boron magnet and a preparation method thereof, the component of the thermal deformation neodymium-iron-boron magnet is RaCobBcNidCueTfFebal, R is one or more rare earth elements taking Nd as an essential element, T is selected from one or two of Ti and Zr, a + b + c + d + e + f + bal = 100 (by atomic percent), 13.5 < = a < = 16.5, 0.0 < = b < = 2.0, 5.2 < = c < = 5.6, 0.2 < = d + e < = 3.0, and 0 < = f < = 0.2. In the magnet, non-ferromagnetic grain boundary phases exist on the grain boundaries of the c surface and the ab surface of neodymium iron boron grains.

The invention provides a titanium alloy current-assisted vacuum brazing tool and process method. The titanium alloy current-assisted vacuum brazing tool and process method comprises the steps that S1, a titanium alloy columnar body to be welded is machined; s2, TiZrCuNi brazing filler metal alloy powder is adopted for preparing a brazing middle layer; s3, polishing the welding surface of the titanium alloy cylindrical body to be welded; s4, the welding face of one to-be-welded titanium alloy base material is placed upwards, brazing filler metal alloy powder of a brazing middle layer is evenly spread, the welding face of the other titanium alloy base material is placed above the middle layer downwards, and a three-layer structure is formed; s5, a workpiece to be welded and a thermocouple are inserted into a titanium alloy current auxiliary vacuum brazing tool and then placed in a vacuum hot-pressing brazing furnace, graphite cushion blocks are arranged at the top of the upper-layer base metal and the bottom of the lower-layer base metal correspondingly, and an electrode pressing head makes contact with the graphite cushion blocks at the top of the upper-layer base metal; and S6, titanium alloy current auxiliary vacuum brazing is conducted. According to the method, the workpiece is rapidly and uniformly heated in a heating and current applying mode, and the titanium alloy brazed joint which is good in bonding strength and excellent in performance is prepared.

The invention provides a method for remarkably improving the coercive force of a cerium-rich neodymium-iron-boron magnet. The method comprises the following steps: (1) preparing cerium-rich magnetic powder I of which the cerium content accounts for not less than 24% of the total content of rare earth; (2) preparing cerium-poor rare earth-rich magnetic powder II in which the cerium content is not more than 24% of the total content of rare earth and the total content of the rare earth is more than 30%; (3) preparing low-melting-point nano metal powder III by taking at least one of Ga, Al, Zn and Sn as a raw material; (4) magnetic powder I, magnetic powder II and metal powder III with the mass being m1, m2 and m3 are taken and mixed uniformly according to the ratio that (m2 + m3): m1 is larger than or equal to 1 and larger than 0, and after uniform mixing, orientation forming, sintering and cutting machining are conducted to prepare a base material; and (5) the surface of the base material is coated with the diffusion source, the weight of the base material is increased by md, 0.05 > = md: (m1 + m2 + m3) > 0, then heat treatment is conducted, and the cerium-rich neodymium-iron-boron magnet is obtained. The prepared cerium-rich neodymium-iron-boron magnet has the advantages of being excellent in performance, low in cost, high in cost performance and the like, and especially compared with a conventional cerium-rich neodymium-iron-boron magnet, the coercive force of the cerium-rich neodymium-iron-boron magnet is greatly improved.

The invention relates to xBC battery slurry based on Ti, Cu and a Cu-Ti alloy. The xBC battery slurry comprises 85-90 wt% of a conductive phase; based on the total mass of the conductive phase, the conductive phase comprises 5-15 wt% of composite Ti powder, 10-30 wt% of composite Cu powder, 5-25 wt% of Cu-Ti alloy powder and 30-80 wt% of Ag powder; 3 to 6 wt% of a glass phase; 0.5 to 3 wt% of an auxiliary material; and the balance is a carrier. The invention also relates to a preparation method of the slurry, which comprises the following steps: S1, putting the solvent into a heating container, keeping the temperature at 50 DEG C, slowly adding the resin and stirring to form the organic carrier; s2, adding an auxiliary agent into the organic carrier, keeping the temperature at 50 DEG C, continuously stirring so that the auxiliary agent and the organic solvent are fully and uniformly mixed to form an auxiliary material, and then standing at room temperature for more than 12 hours for later use; s3, adding a glass phase and Ag powder into the auxiliary material, and stirring and dispersing; s4, Cu alloy powder is added into the auxiliary materials, stirring and dispersing are continued, and paste is obtained; and S5, uniformly dispersing the paste obtained in the step S4 to obtain the slurry.

The invention discloses TiVNbTaX refractory high-entropy alloy brazing filler metal and a brazing method thereof, and the TiVNbTaX refractory high-entropy alloy brazing filler metal is characterized in that the brazing filler metal comprises the following elements in percentage by atom: 14.00 to 16.75 percent of Ti, 14.00 to 16.75 percent of V, 14.00 to 16.75 percent of Nb, 14.00 to 16.75 percent of Ta and 33.00 to 44.00 percent of X, and the X is Ni or / and Co element. The liquidus of the brazing filler metal is located between 1050 DEG C and 1250 DEG C, the brazing temperature is 30-50 DEG C higher than the liquidus, and the brazing time is 8-15 min; and then cooling to 800-900 DEG C, and keeping the temperature for 1-2 hours, so that the Ni and Co elements are fully diffused to the base metal on the two sides. According to the TiVNbTa refractory high-entropy alloy brazing method, TiVNbTa refractory high-entropy alloy brazing can be achieved, and high-entropy transformation of a brazing seam structure is achieved.

The invention discloses a preparation method for in-situ generation of an Al3Fe nanoparticle reinforced aluminum-based composite material, and belongs to the technical field of metal-based composite material preparation. Comprising the following steps that (1) mixed powder is prepared, and the mixed powder is weighed according to the mass percent of 3%-13% of nano carbon-coated iron powder and the balance pure Al; (2) carrying out ball-milling treatment on the mixed powder, loading the mixed powder into a ball-milling tank, and carrying out ball-milling treatment on the mixed powder in an argon environment; (3) sintering and molding; (4) carrying out hot extrusion on the sintered composite material block; the tensile strength of the high-volume-fraction in-situ generated Al3Fe nano-particle reinforced aluminum-based composite material at room temperature reaches 473.76 MPa, the hardness reaches 175.47 HV, the tensile strength at high temperature can reach 204.63 MPa, and the high-volume-fraction in-situ generated Al3Fe nano-particle reinforced aluminum-based composite material has the advantages of being high in strength, resistant to abrasion, low in thermal expansion coefficient, excellent in heat-conducting property and the like.

The invention provides a high-temperature-resistant coal catalytic gasification catalyst and a preparation method thereof, and relates to the field of catalysts. The method comprises the following steps: carrying out pyrolysis treatment on a coal base to obtain semi-coke, dipping the semi-coke in organic metal salt of alkali metal to form a catalyst precursor, adding a modifier into the catalyst precursor for modification treatment, and compounding the modified catalyst precursor with an active component in an ion exchange mode to prepare the composite catalyst. When the prepared catalyst reacts for 300 minutes, the conversion rate reaches 89.1%, the accumulated methane generation amount reaches 12.9 mmol.g <-1 >, the content of methane in the product reaches 26.4%, and the catalyst shows excellent methane preparation performance.

The invention belongs to the field of polyvinyl alcohol composite films, and particularly relates to a preparation method of a high-performance hydrophobic polyvinyl alcohol composite film. By adopting the ternary composite plasticizer, the hydrogen-bond interaction in PVA molecules can be destroyed, the crystallinity and the melting point of PVA are reduced, and the plasticizing effect on PVA is remarkable. Compared with a single plasticizer and a binary plasticizer, the PVA film modified by the ternary composite plasticizer is good in hydrophobicity and excellent in mechanical property. The PVA film is modified by adopting a chemical cross-linking mode, the hydroxyl in PVA molecules is masked through esterification reaction of pyromellitic acid and hydroxyl of PVA, cross-linking can be realized, the hydrophobic property of PVA can be improved, and the mechanical property of the PVA film can also be improved.

The invention relates to an all-solid-state lithium battery and a preparation method thereof. The all-solid-state lithium battery comprises a positive electrode, a negative electrode, a solid electrolyte membrane and a barrier layer arranged between the negative electrode and the solid electrolyte membrane, the solid-state electrolyte membrane comprises a first halide solid-state electrolyte, the barrier layer comprises a second halide solid-state electrolyte, the chemical general formula of the second halide solid-state electrolyte is Li3MCl6-xBrx, M is a trivalent metal ion, 0 lt; xlt; 6; and the second halide solid electrolyte in the barrier layer is converted from a solid state to a liquid state and then is converted from the liquid state to the solid state. According to the all-solid-state lithium battery provided by the invention, the dense barrier layer comprising the second halide solid electrolyte is arranged between the negative electrode and the solid electrolyte membrane, so that the growth of lithium ions in the solid-state lithium ion battery is effectively inhibited, and meanwhile, the ionic conductivity is improved, the interface impedance is reduced, and the internal resistance of the battery is reduced.

The invention provides a modified copolyester film as well as a preparation method and application thereof. The modified copolyester film is prepared from the following raw materials: binary acid, dihydric alcohol and a catalyst, the binary acid comprises 2, 5-furandicarboxylic acid and other binary acid; the dihydric alcohol comprises neopentyl glycol and other dihydric alcohol. 2, 5-furandicarboxylic acid is introduced into a modified copolyester molecular chain, so that the polarity and hydrophilicity of polyester are improved, the interfacial interaction force between the polyester surface and a copper foil is increased, and the adhesive force between the polyester surface and the copper foil is improved; neopentyl glycol is introduced into a modified copolyester molecular chain, so that the regularity of polyester is further destroyed, the crystallinity and the melting point of polyester are reduced, the film is easier to soften or partially melt when in contact with a copper foil, the contact area between the film and the copper foil is increased, mutual diffusion between the film and the copper foil is increased, and the bonding strength between the film and the copper foil is improved.

The invention belongs to the technical field of low-melting-point alloys, and provides a low-melting-point gallium-based liquid alloy and a preparation method and application thereof. The preparation raw materials of the gallium-based liquid alloy comprise gallium, indium, tin, zinc, bismuth, antimony, lead and rare earth metal with specific mass content. The rare earth metal comprises one or two of lanthanum, cerium and neodymium. A trace amount of one or two of lanthanum, cerium and neodymium is added into the gallium-based alloy, so that the purity of the alloy can be improved, the viscosity can be reduced, and the surface tension can be adjusted; by adjusting the formula of the alloy, the smelting time is shortened in the alloy smelting process stage, the efficiency is improved, the alloy cost is reduced, the alloy is more uniform macroscopically, the low-temperature stability of the alloy is further improved, and the alloy can be kept in a stable liquid state at the low temperature even 10 DEG C below zero and better meet the special climate requirements.

The invention relates to silver-based multi-element near-eutectic medium-temperature vacuum brazing filler metal and a preparation method thereof, and belongs to the field of non-ferrous metal brazing. The brazing filler metal is prepared from the following components in percentage by weight: 19.5 to 21.0 weight percent of Cu, 9.0 to 10.0 weight percent of In, 4.5 to 5.5 weight percent of Ge, 4.2 to 4.8 weight percent of Sn, 1.8 to 2.2 weight percent of Ni, 1.7 to 2.0 weight percent of Si, 0.05 to 0.2 weight percent of Co and the balance of Ag. The preparation method comprises the steps of intermediate alloy preparation, vacuum medium-frequency induction melting, centrifugal rapid cooling casting, vacuum heat treatment regulation and control, hot rolling cogging, surface treatment and precise cold rolling. The alloy is low in melting point, low in required vacuum brazing temperature, excellent in wetting characteristic for stainless steel, high in joint strength after brazing and capable of meeting the requirements for medium-temperature vacuum brazing packaging, gradient brazing and repair welding of 316L stainless steel base materials in vacuum electronic devices.

The invention discloses a welding material for preparing an aluminum-steel gradient structure. The welding material comprises alloy powder for laser cladding and an aluminum-based welding wire for CMT welding. The alloy powder for laser cladding comprises the following components in percentage by mass: 20.0%-30.0% of Zn powder, 20.0%-30.0% of Cu powder, 5.0%-10.0% of Si powder, 5.0%-10.0% of Sn powder and the balance of Al, the aluminum-based welding wire for CMT welding comprises powder and a welding skin, and the powder comprises, by mass, 20.0%-30.0% of Zn powder, 20.0%-30.0% of Ag powder, 10.0%-20.0% of Cu powder, 5.0%-10.0% of Si powder, 5.0%-9.0% of Mg powder and the balance Al powder. The structure solves the problems of cracking and poor performance caused by mismatching of thermal physical properties and brittle phases of an aluminum-steel dissimilar structure. The invention further provides a laser and CMT composite preparation method of the aluminum-steel gradient structure.

The invention relates to the technical field of electrode wires, and discloses a molybdenum-tungsten composite material and a preparation method thereof in order to solve the problem of too fast loss of a composite doped molybdenum wire electrode wire, and the molybdenum-tungsten composite material comprises the following components in percentage by mass: 10-16% of tungsten, 0.1-0.15% of lanthanum and the balance of molybdenum and inevitable impurity elements; 5-12% of tungsten and molybdenum form a molybdenum-tungsten alloy matrix, the balance tungsten is pure tungsten mass points, the molybdenum-tungsten alloy matrix is a uniform molybdenum-tungsten alloy solid solution formed by tungsten and molybdenum, and the pure tungsten mass points are pure tungsten dispersed and distributed in the molybdenum-tungsten alloy solid solution. The molybdenum-tungsten composite material comprises a molybdenum-tungsten alloy solid solution formed by tungsten and molybdenum and pure tungsten particles dispersed and distributed in the molybdenum-tungsten alloy solid solution, in the subsequent discharging process, due to the point effect, discharging is mainly concentrated on the pure tungsten particles with higher ablation resistance, and the ablation resistance of the pure tungsten particles is improved through the high melting point of tungsten. Therefore, the wire loss of the wire cut electrical discharge machining electrode wire in the discharging process can be reduced, and the service life of the electrode wire is prolonged.

The invention relates to the technical field of new energy, and discloses a preparation method of a high-capacity high-magnification polycrystalline ternary positive electrode material, which comprises the following steps: mixing a nickel-cobalt-manganese precursor with a dopant A and a lithium source, carrying out primary sintering to obtain a primary sintering material, crushing the primary sintering material, mixing with a coating agent B and a coating agent C, and carrying out secondary sintering to obtain the high-capacity high-magnification polycrystalline ternary positive electrode material. In the primary sintering process, a first heat preservation platform, a second heat preservation platform and a third heat preservation platform are included, the temperature of the first heat preservation platform ranges from 660 DEG C to 700 DEG C, the heat preservation time ranges from 1.5 h to 2.5 h, the temperature of the second heat preservation platform ranges from 850 DEG C to 900 DEG C, the heat preservation time ranges from 1.5 h to 2.5 h, the temperature of the third heat preservation platform ranges from 750 DEG C to 790 DEG C, and the heat preservation time ranges from 4 h to 6 h. Through the design, the capacity and the cycle performance of the ternary positive electrode material are obviously improved. The invention further discloses the high-capacity and high-rate polycrystalline ternary positive electrode material and a battery.