36 results about "Tin-silver-copper" patented technology

The invention discloses an intelligent assembly method of a precise connector, which comprises the following steps of: adding phase change particles with different melting points into tin-silver-copper-based solder according to the difference of functional areas of welding spots in the connector, generating an area formula index, and obtaining composite solder with partition identification; according to the area formula index, the composite welding flux is deposited to preset welding spot positions according to the functional areas, and particle distribution information is recorded; performing reflow soldering on different functional areas by adopting corresponding temperature curves according to the melting point parameters of the phase change particles, and recording the temperature history of each area; applying pulse thermal excitation to the packaged connector, and collecting a surface temperature change curve of each welding spot to obtain thermal response data; and performing correlation comparison on the thermal response data and process historical data, identifying the welding spot defect type according to curve deviation characteristics, and generating process adjustment parameters. According to the scheme, after the connector is completely packaged, rapid nondestructive detection of internal tiny welding spots can be realized, hidden defects can be effectively identified, and intelligent optimization and adjustment of process parameters can be realized.

A solder composition includes a solder paste including a tin (Sn)-bismuth (Bi) alloy and / or a tin (Sn)-silver (Ag)-copper (Cu) alloy and a plurality of nanoparticles dispersed in the solder paste, wherein each of the nanoparticles includes a core that is spherical, the core includes a metal oxide, and the metal oxide has a density of 7 g / cm3 or more and a melting point of 2000° C. or higher.

A welding method of a solar cell module belongs to the field of solar cell modules, and is characterized by comprising the following steps of: coating high-temperature alloy solder on a solder strip in the solar cell module or arranging high-temperature solder paste on a cell piece; secondary high-temperature heating is carried out on the solar cell module in the lamination process or after lamination treatment, and welding between the welding strip and the cell piece is achieved by melting the high-temperature alloy welding flux on the welding strip or the high-temperature solder paste on the cell piece. By adding a heating process on the lamination temperature, the problems that welding spots are not firm and are easy to fall off in the existing welding process can be effectively solved; meanwhile, the welding method can heat the whole string or the whole assembly at the same time, energy consumption is low, efficiency is high, and energy conservation and high efficiency are achieved; and tin-lead solder paste or tin-silver-copper high-melting-point solder paste can be compatible, solder paste with various melting points and components can be matched according to battery paste and solder strip surface materials, the design requirements of different assemblies are met, the application range is wide, and the method is suitable for application and popularization.

The invention relates to the field of welding materials, in particular to high-temperature-resistant antioxidant solder paste and a preparation method thereof. The high-temperature-resistant antioxidant solder paste comprises the following raw materials: a tin-silver-copper alloy, temperature-resistant copolymer resin, an antioxidant, a thixotropic agent, a corrosion inhibitor, a dispersing agent, a functional compound and the like. The finally prepared solder paste material not only can maintain excellent high temperature resistance and oxidation resistance, but also can maintain good corrosion resistance, water resistance, toughness and the like at the same time, so that performance contradictions of the solder paste material are eliminated while the problems of temperature resistance and oxidation resistance of an existing solder paste material are solved, and the service life of the solder paste material is prolonged. Therefore, the solder paste meets the comprehensive performance requirements of existing electronic products and other fields on solder paste materials, and has wide application potential.

The utility model discloses a low melting point solder ball relates to solder ball field, including inner ball core and antioxidation protection mechanism, the top of inner ball core is provided with the straight-through hole equidistantly of annular array, and the side edge of inner ball core is provided with the anti-slip arc groove equidistantly of annular. According to the low-melting-point solder ball, through the arrangement of the straight-through hole and the anti-skid arc-shaped groove, the contact area between the solder ball and heat is larger after the anti-oxidation protection mechanism is molten, so that the melting speed of the solder ball can be further increased, and the situation that the solder ball is not completely molten is effectively prevented; meanwhile, the inner ball core is formed by fusing the tin-silver-copper metal layer and the tin-bismuth metal layer, so that the melting point of the solder ball is lower, the oxidation resistance of the solder ball is more excellent through the arrangement of the anti-oxidation resin layer and the anti-oxidation coating film, and the service life of the solder ball is prolonged. Therefore, the situation that subsequent melting of the solder balls and interference on the welding quality are caused by the oxidation phenomenon after the solder balls make contact with air for a long time is avoided.

To provide a solder composition, and to provide a method of preparing the solder composition and a method of manufacturing a semiconductor package using the solder composition.SOLUTION: A solder composition of the invention includes: a solder paste including at least one of a tin (Sn)-bismuth (Bi) alloy and a tin (Sn)-silver (Ag)-copper (Cu) alloy; and a plurality of nanoparticles dispersed in the adhering solder paste. Each of the nanoparticles includes a core that is spherical. The core includes a metal oxide, and the metal oxide has density of 7 g / cm3 or more and a melting point of 2000°C or higher.SELECTED DRAWING: Figure 2

The invention discloses a tin-silver-copper alloy, a preparation method thereof and solder, and belongs to the technical field of alloy materials, the tin-silver-copper alloy comprises, by mass, 2.8%-3.1% of Ag, 0.3%-0.7% of Cu, 0.01%-0.5% of B, 0.03%-1.0% of P and the balance Sn and impurity elements, and the content of Pb and the content of Fe in the impurity elements are both smaller than or equal to 0.001%. According to the embodiment of the invention, the content of impurity elements in the tin-silver-copper alloy is controlled, the B and P elements are added on the basis of the tin-silver-copper basic elements, the alloy is refined, an oxidation film is formed on the surface of the liquid solder, and the corrosion to a titanium alloy part is reduced.

A preparation method of a tin-silver-copper-aluminum quaternary alloy and its application in the negative electrode of a secondary battery belong to the technical field of secondary batteries. The present invention aims to solve the problems of limited materials, high cost, complex preparation process, and unsatisfactory electrochemical performance of alloy negative electrodes in existing secondary batteries. Method: 1. Using tin, silver, copper, and aluminum targets as raw materials, setting the argon gas flow rate; 2. Setting the magnetron sputtering power parameters of the tin target, silver target, copper target, and aluminum target respectively; 3. Setting the magnetron sputtering time and substrate speed, turning on the magnetron sputtering power supply, starting sputtering on the current collector, and ending sputtering to obtain a tin-silver-copper-aluminum quaternary alloy. A tin-silver-copper-aluminum quaternary alloy is used as the negative electrode active material of a secondary battery. The preparation process of the present invention is relatively simple, so the cost is greatly reduced. The present invention solves the shortcomings of limited lithium resource reserves and high cost of existing lithium-ion batteries. In addition, the present invention is simpler, safer, more reliable, and has higher energy density than existing sodium-ion batteries.

This invention relates to the field of solder powder technology, specifically to an antioxidant solder powder and its preparation method. The solder powder uses SAC305 tin-silver-copper alloy solder powder as a matrix, and its surface has an antioxidant treatment layer formed by segmented anchoring of single-terminated phosphate-based polyether oligomers and spacer regulation by polyethylene glycol monomethyl ether. During preparation, under nitrogen protection, the following steps are performed sequentially: ethyl acetate pre-cleaning, aqueous isopropanol water-limited hydroxylation, two-stage single-terminated phosphate-based polyether anchoring, polyethylene glycol monomethyl ether sacrificial spacer treatment, washing, drying, and sieving. The resulting solder powder exhibits low total oxygen increment after 168 hours of open aging at 40°C and 75% RH. Solder paste made from this powder exhibits low viscosity drift, high spreadability, and low solder joint void ratio, making it suitable for high-reliability electronic assembly solder paste.

The application discloses a high-lead semiconductor solder wire with an anti-oxidation surface, a manufacturing process and application thereof, and belongs to the technical field of welding materials. The solder wire comprises the following components in percentage by weight: tin: 5-10%; silver: 0.5-1.5%; copper: 0.1-0.5%; bismuth: 0.1-0.3%; antimony: 0.1-0.3%; red phosphorus: 0.05-0.1%; germanium: 0.05-0.1%; and lead: the balance. The high-lead semiconductor solder wire produced by the alloy ratio and process conditions of the application has a more stable and dense surface structure, reduces active sites for reaction with oxygen, forms a protective film with an anti-oxidation effect on the surface of the solder wire, further prevents the contact between oxygen and the solder wire, and thus realizes a better oxidation prevention effect.

The invention provides an embedded micro-channel based on additive manufacturing and a preparation method thereof, the embedded micro-channel is suitable for heat dissipation of a high-power electronic device, and the first scheme is single-substrate integrated electroplating: sequentially forming a seed layer and graphical photoresist on a substrate, controlling electroplating to enable copper to grow vertically and transversely, and forming an all-copper micro-channel cavity with a closed top in a self-closing manner; turbulent flow structures such as micro-columns, waves or fins are integrally formed; according to the second scheme, complementary half cavities are formed through electroplating, tin-silver-copper solder is applied after surface nickel plating, a complete flow channel is formed through reflow soldering bonding, photoetching and electroplating are utilized in the two schemes, an integrated structure which is high in precision and free of interface thermal resistance is achieved, the heat exchange efficiency is remarkably improved, and the heat exchange efficiency is improved. Moreover, the material utilization rate is high, and ceramic, silicon and glass substrates are compatible, and are respectively suitable for high-end power modules and low-cost consumer electronics scenes.

This application provides a high spreadability halogen-free and lead-free solder paste, comprising solder alloy powder and flux. The solder alloy powder consists of tin, silver, copper, zirconium, yttrium, rhodium, and palladium. The addition of yttrium significantly improves the strength, hardness, and heat resistance of the tin alloy, increases the melting point of the solder wire, and enhances the oxidation resistance and ductility of the tin alloy. The addition of trace amounts of rare earth elements to the tin alloy improves the solidification and crystallization state of the solder, increases the melting point of the solder wire, and improves the tensile strength and toughness of the solder. The flux includes rosin, thermosetting resin, thixotropic agent, activator, surface activator, and solvent. The copolymer of rosin and thermosetting resin is used as the main component, which not only enhances the soldering ability of the metal surface but also improves the elongation toughness of the solder wire. It can effectively reduce the presence of post-soldering residues, avoid corrosion of the substrate, and prevent the final product from being affected. The method for preparing a high spreadability halogen-free and lead-free solder paste provided by this invention involves the sequential preparation of flux and solder alloy powder. The process is simple, the reaction is mild, and no harmful gases are generated during the process, making it suitable for mass production.

The invention discloses a corrosion-resistant titanium alloy, a preparation method of the corrosion-resistant titanium alloy and a machining part for welding, and belongs to the technical field of alloy materials, the corrosion-resistant titanium alloy comprises, by mass, 1%-8% of Al, 0.5%-1.5% of Mo, 0.03%-0.16% of Cr, 1.5%-4.5% of Zr, 0.03%-0.09% of Y and the balance Ti and impurity elements, and the impurity elements are Fe, N, H and / or O; the content of impurity elements is less than or equal to 0.15%. According to the embodiment of the invention, proper elements such as Al, Mo, Cr, Zr and Y are added into the titanium alloy to form an inert oxide protective film, and meanwhile, the content of impurity elements is strictly controlled, so that the technical effect of improving the corrosion resistance of the titanium alloy part to the tin-silver-copper solder is achieved.

The invention discloses tin-silver-copper soldering paste for high-stability fine-pitch welding, and belongs to the technical field of soldering flux. On one hand, in the high-temperature forming process of the alloy powder, the 685 modified rosin is added for coating, then the 685 modified rosin is washed away, and the AX-E modified rosin and the antioxidant are coated on the surface of the alloy powder; on the other hand, the film-forming agent and the active agent form a film-forming agent-active agent microcapsule by adopting a microcapsule technology, and the two improvement points are combined, so that good wettability of the tin-silver-copper soldering paste for high-stability micro-pitch welding after high-temperature welding is ensured; and the stability of the tin-silver-copper soldering paste for high-stability micro-pitch welding in the low-temperature storage process is greatly improved, and the interface stability between the superfine solder alloy powder and the soldering flux is remarkably improved.

The utility model discloses a microwave composite heating sintering device for nano-tin-silver-copper solder paste, comprising a shell, a material transfer mechanism and a monitoring mechanism, wherein a sealing door and an equipment door are rotatably connected to the shell, a heating platform is arranged on one side of the storage table, and the heating platform is connected to a microwave heating component. In the microwave composite heating sintering device for nano-tin-silver-copper solder paste, a microwave heating component develops a three-dimensional numerical simulation model to predict the electromagnetic field and temperature field distribution during microwave composite heating brazing with the cooperation of COMSOL software, and establishes a heating effect database for different microwave receptors, and establishes a surface model of microwave power / frequency / exposure time by response surface method, so as to predict the welding process parameters of microwave composite heating brazing and the electromagnetic field and temperature field during the welding process, thereby reducing the waste of financial and material resources in the process of process optimization to a certain extent, that is, achieving the purpose of energy saving.

A solder composition, a method of preparing the same, and a method of manufacturing a semiconductor package using the same are provided. The solder composition includes a solder paste including a tin (Sn)-bismuth (Bi) alloy and / or a tin (Sn)-silver (Ag)-copper (Cu) alloy, and a plurality of nanoparticles dispersed in the solder paste, in which each nanoparticle includes a spherical core, the core includes a metal oxide, and the metal oxide has a density of 7 g / cm3 or more and a melting point of 2000 DEG C or more.

This application relates to the field of manufacturing ultra-fine diameter lead-free solder wires. Specifically, it discloses an ultra-fine diameter lead-free silver-copper-tin solder wire and its manufacturing process. The method is as follows: A tin-silver-copper alloy column containing 0.2% - 4.0% silver, 0.2% - 1% copper, 0.01% - 0.2% trace elements, and the balance being tin is extruded into a metal wire with a diameter of 10 mm - 12 mm at a temperature of 110°C - 135°C, a pressure of 30 bar - 50 bar, and an extrusion speed of 16 mm / s - 21 mm / s. During the extrusion process, 3% - 6% of a solid soldering flux is added. The parameters of the extrusion die are as follows: the arc angle β of the feed inlet ranges from 50° to 51.5°, the depth of the feed inlet is 11.5 mm - 12.5 mm, the length a of the reducing zone ranges from 3.5 mm to 4.0 mm, the arc angle α of the discharge outlet ranges from 86° to 87°, and the depth b of the discharge outlet ranges from 1 mm to 3 mm; then the metal wire is stretched to a wire diameter of 0.10 mm - 0.12 mm.

The invention relates to a raw material composition of a conductive paste, the conductive paste, a battery piece and a preparation method thereof, and belongs to the technical field of conductive pastes.The raw material composition of the conductive paste is prepared from, by mass, 72%-82% of composite powder, 15%-25% of organic carriers and 3% of nickel powder; the composite powder comprises tin powder, silver powder and copper powder. After the paste disclosed by the invention is cured, the molten tin-silver-copper and the silver grid line form good ohmic contact, and the molten nickel powder fills pores generated by shrinkage of the grid line and permeates into the pores formed by melting of the tin-silver-copper, so that the compactness and continuity of the grid line are remarkably improved, and the resistivity of the grid line is greatly reduced.

The application provides a high-wetting halogen-free lead-free soldering paste, which comprises solder alloy powder and flux, wherein the solder alloy powder comprises tin, silver, copper, zirconium, cerium, scandium and iridium; by adding a small amount of rare earth elements scandium and cerium and a small amount of metal elements zirconium and iridium, signal interference caused by the soldering paste when used for integrated circuit board assembly can be reduced, signal interference caused by material nonlinearity can be reduced, the mutual cooperation of scandium and iridium has good heat conduction, electric conduction and ductility, the storage stability of the soldering paste is improved, the strength, hardness and heat resistance of the alloy are improved, the surface insulation resistance and reliability are improved, and the dielectric loss is reduced. The application further provides a preparation method of the high-wetting halogen-free lead-free soldering paste, wherein the flux and the solder alloy powder are prepared in sequence, the process is simple, the reaction is mild, no harmful gas is generated in the process, and the method is suitable for mass production.

The invention relates to the technical field of solder paste production, in particular to a solder paste formula capable of reducing solder joint holes and a preparation process. The solder paste formula capable of reducing solder joint holes comprises tin, silver, copper, rosin, a solvent, a trace additive element group package, a curing group package, a reduction group package, antimony, manganese, glutaric acid, benzotriazole and a surfactant. According to the process, stable electrical connection is provided by reducing welding spot cavities, and a larger and more continuous path is formed in a welding spot due to small cavity current, so that the phenomenon of current crowding is reduced, and local overheating and potential signal interruption risks are avoided; the welding spots are not only electrically connected, but also key heat conduction paths of power devices such as a CPU, a GPU and a power MOSFET, metal is a good heat conductor, the cavities are heat insulators, the welding spots with small cavities are lower in thermal resistance, heat generated by a chip can be more efficiently transmitted to a PCB and dissipated, the junction temperature of the chip can be directly reduced, and the small cavities are used for preventing the devices from being overheated, so that the reliability of the device is improved. And the long-term reliability is ensured.

The present invention provides a welding method for a chip heat sink assembly with a low void ratio. Laser scribing is used to locate the welding position on the casing, effectively controlling the welding precision and preventing solder overflow. The welding area of the casing is pre-tinned by heating, melting and cooling a tin-silver-copper solder sheet. The welding surface of the chip heat sink assembly is tinned. The chip heat sink assembly is placed at the pre-tinned welding position of the casing, and the welding is completed in a vacuum sintering furnace without any tooling pressure. The present invention adopts a precise tin plating method of laser scribing + solder sheet pre-melting, avoiding the overflow of solder during post-treatment, preventing the overflow of solder from contaminating the surrounding mounting positions, and ensuring the high-precision welding of the chip heat sink assembly. At the same time, the "zero pressure" welding mode is successfully applied, not only obtaining a welding effect with a very low void ratio, but also eliminating the need for customized tooling, being easy to operate, solving the problems of surface damage and contamination of bare chips such as gallium arsenide and gallium nitride, and enabling the very low void ratio, high-efficiency and low-cost welding of multi-channel power chip heat sink assemblies at one time.

This invention relates to the field of tin alloy solder technology and discloses a lead-free multi-element alloy solder, a tin material. The tin material is formed by pouring molten liquid metal into the interior of a mold assembly and cooling it. The composition of the tin material includes tin, silver, copper, bismuth, antimony, and nickel. The weight ratio of the composition of the tin material is: tin: 92-93 parts; silver: 2-3.5 parts; copper: 0.46-0.54 parts; bismuth: 1-2 parts; antimony: 2.5-3 parts; nickel: 0.05-0.1 parts. This invention uses a first scraper that moves on the top of the mold body to scrape off oxides and impurities on the surface of the liquid metal. When the first scraper moves to one side of the fixed frame, it moves to the side of the second scraper. Then the first scraper moves upward, and the second scraper can scrape off the oxides and impurities on the first scraper, avoiding secondary pollution. This allows for the cyclical scraping of oxides and impurities on the surface of the liquid metal, improving the aesthetics of the tin material and the overall quality of the soldering.

The application provides an insulating mounting base of a piezoelectric vibration sensor and a preparation method thereof, relates to the technical field of piezoelectric vibration sensors, and rigidly connects an insulating gasket between an upper seat and a lower seat in a fusion welding mode, realizes electrical insulation between the upper seat and the lower seat through the barrier of the insulating gasket, and realizes the rigid connection between the upper seat, the insulating gasket and the lower seat through a eutectic welding process combining an aluminum nitride ceramic copper-clad plate and a tin-silver-copper soldering sheet, so that the bonding strength of the bonding surface is high and the mechanical impact resistance is good. The upper seat of the insulating mounting base is fixed on the piezoelectric ceramic vibration sensor through screwing, and then the lower seat is fixed on the object to be tested through screwing, so that the rigid connection between the sensor and the object to be tested is realized, the GND crosstalk problem is solved, the structure is simple and compact, the cost is low, the use is convenient, the insulation effect is good, the rigid connection is realized, and the sensor output signal can be prevented from being disturbed.

The invention discloses a semiconductor paste suitable for low temperature sintering and a manufacturing method thereof, and the semiconductor paste comprises a paste body part and metal particles dispersed in the paste body part. The paste body part contains 15%-25% of propylene glycol monomethyl ether, 4%-9% of isopropyl toluene, 3%-7% of rosin amine polyoxyethylene ether, 3%-5% of glycerol diabietate, 1%-4% of glycerol diabietate ether and 1%-3% of grease turpentine, and the metal particles contain 25%-30% of bismuth powder, 3%-6% of indium powder and the balance tin-silver-copper alloy powder. During preparation, the paste part is prepared through hot melting stirring and emulsification, and the metal particles are prepared through granulation processing; and uniformly mixing the paste part with the metal particles through vacuum stirring to obtain the semiconductor paste which is low in sintering temperature, short in sintering time, few in paste residue after sintering, and excellent in surface corrosion resistance, conductivity and bonding strength.

The invention relates to the technical field of semiconductor laser manufacturing, and provides a method for realizing automatic mounting of a semiconductor laser, which comprises the following steps of: S1, moving a laser shell into a heating stage of a eutectic machine; s2, the TEC and the laser shell are mounted, the eutectic temperature is 280-320 DEG C, and gold-tin solder is selected; s3, the wiring block and the TEC are mounted, the eutectic temperature is 217-240 DEG C, and tin-silver-copper solder is selected; s4, the COC and the wiring block are mounted, the eutectic temperature ranges from 175 DEG C to 210 DEG C, and tin-indium-silver solder is selected; s5, the MPD, the NTC and the PZT are all mounted on the wiring block, the eutectic temperature is 145-170 DEG C, and a tin-bismuth solder is selected; and S6, obtaining a finished product. The method has the beneficial effects that the core idea is that gold tin, tin silver copper, tin indium silver, tin bismuth and other materials are sequentially adopted in the four temperature zones of high temperature, medium high temperature, medium low temperature and low temperature, a reliable mounting sequence is provided, and the performance of the semiconductor laser is improved.

The invention discloses a tough soldering flux for tin-silver-copper alloy soldering lug coating and a preparation method of the tough soldering flux, and the soldering flux comprises the following components in percentage by mass: 10%-20% of a film-forming agent, 2%-5% of an activating agent, 1%-2% of a toughening component, 0.05%-1% of a surfactant, 0.05%-0.15% of a corrosion inhibitor, 5%-10% of a cosolvent and the balance of a solvent. The toughening component is selected from one or two of polyurethane and acrylic acid rosin ethylene glycol diglycidyl ether. By introducing the toughening component and optimizing the proportion of the film-forming agent, the solvent and the like, the obtained flux coating has excellent flexibility and punching resistance, broken particles generated in the welding strip punching process can be remarkably reduced, adhesion and abrasion to a mold are reduced, the continuous working time of the mold is prolonged, and therefore the production efficiency and the product yield are greatly improved; and meanwhile, good welding performance is kept.

The utility model discloses a kind of tinned silver copper alloy stranded conductor processing equipment, belong to stranded conductor processing technical field, aiming at the burr produced in the process of wire stranding reduces the problem of product appearance quality, including bottom plate, the bottom plate top is fixedly connected with branch plate, the utility model is through being provided with cleaning mechanism, after stranding, wire passes through from inside carousel and first disc, knob rotation drives worm rotation, so that worm gear cover drives carousel rotation, multiple arc-shaped guide slots promote guide pillar to move, multiple guide pillars drive multiple sliding slots to move simultaneously to inner end, so that multiple scrapers move inward and adhere to wire surface, in the process of conveyor moving wire, multiple scrapers and wire surface friction to remove burr, to improve the smoothness of conductor surface, not only improve the appearance quality of conductor, but also ensure the electrical performance of conductor, avoid the electrical contact bad or signal interference caused by burr.

The invention provides a pin conductor capable of preventing tin whisker and fretting wear, which is provided with a core material made of copper or copper alloy, and a nickel layer and a tin-silver-copper alloy layer which are sequentially coated outside the core material, and the tin-silver-copper alloy comprises the following components in percentage by weight: 2-4% of silver, 0.2-1.0% of copper and the balance of tin; the invention also provides a manufacturing method of the pin conductor capable of preventing tin whisker and fretting wear, which comprises the following steps: sequentially carrying out deformation processing, electroplating of the middle nickel layer and hot dipping of the tin-silver-copper alloy layer on the high-strength and high-conductivity copper or copper alloy conductor material, and then carrying out cold deformation processing to draw the whole conductor material. The binding force between the core material and the plating layer is further improved, the hardness and wear resistance of the pin conductor are improved, tin whiskers are effectively prevented from being generated in the use process of the pin conductor, and meanwhile fretting wear is reduced.

The invention relates to a tin solder with high welding spot smoothness and a preparation method thereof, and relates to the technical field of metal welding materials, the tin solder comprises the following components in parts by weight: 0.3-4.0 parts of silver, 0.1-1.0 part of copper, 0.5-8.0 parts of indium, 0.005-0.5 part of gallium, 0.001-0.01 part of germanium, 0.002-0.02 part of an endogenous nucleating agent and the balance of tin; the endogenous nucleating agent is titanium or manganese. The preparation method comprises the following steps: smelting in advance to prepare a Sn-Ti or Sn-Mn intermediate alloy; melting tin, silver and copper to prepare matrix alloy liquid; cooling, adding the intermediate alloy, and dispersing by utilizing shearing force; and further cooling, adding indium, gallium and germanium, gently stirring, standing, and casting, extruding and forming. The endogenous nucleating agent induces the solidification interface to advance from inside to outside, and in cooperation with the volume repulsion effect of crystal growth, the low-surface-energy components indium and gallium are promoted to be enriched towards the surface and form a liquid film to fill up microdefects. And the obtained welding spot is extremely low in surface roughness, small in contact resistance, excellent in oxidation resistance and relatively high in shear strength and thermal fatigue resistance.

The application relates to the field of welding materials, and more particularly to a high-temperature-resistant and oxidation-resistant tin paste and a preparation method thereof. The raw materials of the high-temperature-resistant and oxidation-resistant tin paste include a tin-silver-copper alloy, a temperature-resistant copolymer resin, an antioxidant, a thixotropic agent, a corrosion inhibitor, a dispersing agent and a functional composite, etc. The tin paste material prepared finally not only has excellent high-temperature resistance and oxidation resistance, but also has good corrosion resistance, waterproofness and toughness, etc., so that the problems of the high-temperature resistance and oxidation resistance of the existing tin paste material are solved, the performance contradictions of the tin paste material are eliminated, the comprehensive performance requirements of the tin paste material in the existing electronic product field are met, and the tin paste material has wide application potential.