A silver-based alloy material and a method for producing the same

Abstract

This invention discloses a silver-based alloy material and its preparation method, belonging to the field of alloy material preparation technology. It is used to solve the technical problems of the wide melting temperature range and insufficient spreading performance of existing silver-based alloy materials. This invention uses silver-copper-tin-zinc composite precursor powder as a base, introduces silver-deposited copper-tin composite particles, silver-loaded copper-zinc-tin flake precursors and cerium-containing silver-copper-tin composite particles, constructs silver-based multi-component composite precursor powder through the action of tris(hydroxymethyl)aminomethane / dopamine, and obtains silver-based multi-component alloy powder and silver-based alloy material through staged heat treatment, thereby helping to reduce the melting temperature range and improve the spreading coefficient.

Description

Technical Field

[0001] This invention relates to the field of alloy material preparation technology, specifically to a silver-based alloy material and its preparation method. Background Technology

[0002] Silver-based alloys possess excellent thermal and electrical conductivity, as well as adjustable composition, making them highly valuable for applications in electronic sealing, metal bonding, and related material preparation. Existing silver-based alloy materials are typically prepared by atomization powdering, mechanical mixing, surface coating, chemical deposition, or multi-step composite processing to obtain silver-based multi-element alloy powders, which are then further processed through mixing, forming, drying, and heat treatment to obtain the target silver-based alloy material. To adjust the melting characteristics and spreading properties of the material, copper, tin, zinc, and trace amounts of rare earth elements are often introduced into the silver-based system.

[0003] However, in the preparation process of existing silver-based alloy materials, when the silver-based multi-element alloy powder system used contains granular, flake, or surface composite components, due to the differences in particle size, morphology, surface state, and stacking behavior of different components, local aggregation, stratification, or distribution imbalance are likely to occur during mixing, transfer, molding, and pressure rearrangement. This makes it difficult for the components inside the material to form a coordinated and stable transformation process when heated and melted, and local premature melting, delayed melting, or discontinuous liquid phase reception are likely to occur. This is not conducive to narrowing the melting temperature range and uniform spreading of the molten liquid phase, thus affecting the spreading performance of the silver-based alloy material.

[0004] Furthermore, in the subsequent heating and melting alloying processes of existing silver-based alloy materials, the diffusion and interface transition between different components often lack effective coordination, which can easily lead to uneven component migration, insufficient microstructure continuity, and differences in densification in local areas, further affecting the overall performance of the material. Therefore, developing a silver-based alloy material and its preparation method that can reduce the melting temperature range, improve the spreading coefficient, and exhibit good comprehensive performance in joining applications has strong practical application value.

[0005] To address this technical deficiency, a solution is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a silver-based alloy material and its preparation method, which solves the technical problems of the wide melting temperature range and insufficient spreading performance of existing silver-based alloy materials.

[0007] The objective of this invention can be achieved through the following technical solutions: A silver-based alloy material, wherein the silver-based alloy material comprises a silver-based alloy structure formed by thermal conversion of silver-based multi-element alloy powder, wherein the silver-based multi-element alloy powder comprises Ag, Cu, Sn, Zn and Ce components, wherein Ag is the matrix component, Cu, Sn and Zn are the main alloying components, and Ce is the modifying component; The silver-based multi-element alloy powder is prepared by heat treatment after forming a silver-based multi-element composite precursor powder from silver-copper-tin-zinc composite precursor powder, silver-deposited copper-tin composite particles, silver-loaded copper-zinc-tin flake precursor, and cerium-containing silver-copper-tin composite particles under the action of tris(hydroxymethyl)aminomethane and dopamine hydrochloride.

[0008] Furthermore, the preparation method of the silver-based multi-component composite precursor powder is as follows: according to the dosage ratio, weigh 100g of silver-copper-tin-zinc composite precursor powder, 1.5-2.5g of silver-deposited copper-tin composite particles, 0.5-1.0g of silver-loaded copper-zinc-tin flake precursor, 0.3-0.5g of cerium-containing silver-copper-tin composite particles, 4-7g of tris(hydroxymethyl)aminomethane, 100mL of anhydrous ethanol and 200mL of deionized water and add them to the reaction vessel and stir. After mixing evenly, add 2g of dopamine hydrochloride, control the temperature of the reaction vessel at 25-32℃ and keep it at that temperature for 4-6 hours. After stirring, filter the cake and dry it to obtain the silver-based multi-component composite precursor powder.

[0009] Furthermore, the heat treatment is as follows: silver-based multi-component composite precursor powder is loaded into a tube furnace, nitrogen is introduced for purging, and the temperature is raised to 360-390℃. At the same time, vapor obtained from the evaporation of formic acid is introduced and the temperature is maintained for 0.75-1h. Then, the mixture is switched to a mixed gas and the temperature is raised to 500-540℃ and maintained for 0.5-0.75h. The ratio of silver-based multi-component composite precursor powder to formic acid is 100g:12-15mL, and the mixed gas is obtained by mixing hydrogen and nitrogen in a volume ratio of 1-2:23-24.

[0010] Furthermore, the preparation method of the silver-copper-tin-zinc composite precursor powder is as follows: Weigh 40-50g of metal source, 70-90mL of ethylene glycol and 100mL of deionized water according to the dosage ratio, add them to the reaction vessel and stir. After mixing evenly, add 6-9g of citric acid and 3-5g of sodium formate. Heat the reaction vessel to 58-65℃ and keep it at this temperature for 1.5-2.5h. After stirring, filter the cake and dry it to obtain the silver-copper-tin-zinc composite precursor powder. The metal source is obtained by mixing silver acetate, copper nitrate trihydrate, stannous sulfate and zinc nitrate hexahydrate in a dosage ratio of 45-52g:24-32g:6-8g:5-7g.

[0011] Furthermore, the preparation method of the cerium-silver-copper-tin composite particles is as follows: Weigh 6-10g of mixed metal salt, 8-12g of citric acid, 90-120mL of ethylene glycol, and 50-80mL of deionized water according to the dosage ratio, add them to the reaction vessel and stir. After mixing evenly, heat to 75-85℃ and stir for 45-60min, then heat to 125-135℃ and hold for 1-1.5h, then continue to heat to 240-270℃ and hold for 20-40min. The post-treatment yields cerium-silver-copper-tin composite particles. The mixed metal salt is obtained by mixing cerium nitrate hexahydrate, silver acetate, copper nitrate trihydrate, and stannous sulfate in a dosage ratio of 0.8-1.2g:2.8-4.0g:1.6-2.4g:1.6-2.5g.

[0012] Furthermore, the silver-deposited copper-tin composite particles are prepared by the following method: A1. Weigh out 10-14g of copper sulfate pentahydrate, 18-24g of stannous chloride dihydrate, 240-300mL of ethylene glycol, and 80-120mL of deionized water according to the dosage ratio. Add them to the reaction vessel and stir. After mixing evenly, add 14-20g of glucose and then 8-15mL of alkaline solution. Then, purge with nitrogen for protection and heat the reaction vessel to 80-88℃. Keep it at this temperature and stir for 2.5-3.5h. Post-treatment yields copper-tin multiphase composite particles. The alkaline solution is a 20-25wt% sodium hydroxide aqueous solution. A2. Weigh out 15-18g of copper-tin multiphase composite particles, 4-6g of silver nitrate, 4-5g of trisodium citrate dihydrate, and 260-320mL of deionized water according to the dosage ratio. Add them to the reaction vessel and stir. After mixing evenly, control the temperature of the reaction vessel at 30-35℃ and keep it warm while stirring for 0.5-1h. Post-processing yields silver-deposited copper-tin composite particles.

[0013] Furthermore, the silver-loaded copper-zinc-tin sheet precursor is prepared by the following method: B1. Weigh out 6-8g of copper sulfate pentahydrate, 3-4g of zinc chloride, 4-5g of stannous chloride dihydrate and 220-280mL of deionized water according to the dosage ratio. Add them to the reaction vessel and stir. After mixing evenly, add 45-65mL of regulator. Heat the reaction vessel to 40-45℃ and keep it at this temperature while stirring for 1.5-2 hours. Post-process to obtain copper-zinc-tin flake basic precursor. The regulator is 10-15wt% sodium carbonate aqueous solution. B2. Weigh out 6-8g of copper-zinc-tin flake basic precursor, 0.6-0.9g of silver acetate and 80-110mL of ethylene glycol according to the dosage ratio, add them to the reaction vessel and stir. After mixing evenly, purge with nitrogen gas for protection, then heat the reaction vessel to 150-165℃ and keep it at that temperature for 2-3 hours. Post-process to obtain silver-loaded copper-zinc-tin flake precursor.

[0014] This invention also discloses a method for preparing a silver-based alloy material, comprising the following steps: weighing 20 parts by weight of silver-based multi-element alloy powder and 5 parts by weight of binder liquid and adding them to a mixing vessel, mixing them evenly to obtain a wet mixture, loading the wet mixture into a mold, pressing it into a sheet blank with a thickness of 0.15 mm under a pressure of 100 MPa, then placing it in an 80°C forced-air drying oven for 40 min, and then transferring it to a vacuum furnace for drying at 3×10⁻⁶ ℃. -2 The temperature is raised to 300℃ under Pa conditions and held for 30 min. After cooling, a silver-based alloy material is obtained. The binder is prepared by mixing polyvinyl butyral and anhydrous ethanol at a ratio of 3-4 g: 50 mL.

[0015] The present invention has the following beneficial effects: 1. The silver-deposited copper-tin composite particles prepared by this invention and the silver-loaded copper-zinc-tin lamellar precursor form a composite structure in a silver-based multi-component system where granular and lamellar components coexist. The former is distributed among the basic components, while the latter provides a larger contact interface and a more continuous structural basis. Combined with the interface bonding layer constructed by dopamine and the maintenance effect of the cerium-containing silver-copper-tin composite particles on the dispersion state of heterogeneous components, the components have good distribution uniformity and interface coordination in the silver-based alloy material. This helps to reduce the compositional fluctuations and asynchronous phase transformation tendency in local areas, making the melting transformation of the material more concentrated during the heating process, exhibiting a narrower melting temperature range and better thermal response consistency.

[0016] 2. The silver-loaded copper-zinc-tin sheet precursor prepared by this invention, when introduced into a silver-based multi-component system, can provide a relatively continuous contact base and component diffusion path during subsequent heating and brazing. The sheet component and the silver-deposited copper-tin composite particles work together to facilitate the redistribution, coordinated transformation and continuous transition of each component in local areas, reduce local shrinkage, component agglomeration and interface interruption tendencies during thermal action, and enable the silver-based alloy material to exhibit better wetting and spreading ability during brazing. This is beneficial to improving the spreading coefficient of the material and making the formed brazed seam area have better interface continuity and microstructure integrity.

[0017] 3. When the cerium-containing silver-copper-tin composite particles and silver-deposited copper-tin composite particles prepared by this invention are embedded together in the silver-copper-tin-zinc matrix, they are conducive to building a composite microstructure with clearer layers and smoother transitions during subsequent thermal cycling and brazing. The former helps maintain microstructure coordination and interface continuity, while the latter helps reduce microstructure abrupt changes and performance mismatches in local areas. Combined with the continuous structural foundation formed by the silver-loaded copper-zinc-tin lamellar precursor during thermal conversion, the brazed joint structure formed by the resulting silver-based alloy material is less prone to penetrating defects. This helps improve the microstructure density, stress uniformity, and overall stability of the joint area, resulting in higher tensile and shear strength in the brazed joint and a lower helium leakage rate in the brazed sealing structure, demonstrating better structural integrity, sealing reliability, and overall performance stability. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 Image of the product prepared in Example 3; Figure 2 SEM image of the silver-loaded copper-zinc-tin sheet precursor prepared in Example 6; Figure 3 SEM image of the cerium-silver-copper-tin composite particles prepared in Example 9; Figure 4 This is a SEM image of the silver-based multi-element alloy powder prepared in Example 9.

[0020] Among them, (a) is a low-magnification SEM image of copper-tin multiphase composite particles; (b) is a low-magnification SEM image of silver-deposited copper-tin composite particles; (c) is an EDS elemental distribution map of silver-deposited copper-tin composite particles; and (d) is a high-magnification SEM image of the cross-section of silver-deposited copper-tin composite particles. Detailed Implementation

[0021] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In this application, the polyvinyl butyral used was purchased from Shanghai McLean Biochemical Technology Co., Ltd., with the product number P768881.

[0023] Example 1 This embodiment provides a method for preparing silver-deposited copper-tin composite particles, including the following steps: Step I: Preparation of copper-tin multiphase composite particles Weigh out 10.0 g of copper sulfate pentahydrate, 18.0 g of stannous chloride dihydrate, 240.0 mL of ethylene glycol and 80.0 mL of deionized water and add them to the reaction vessel. Stir and mix well. Then add 14.0 g of glucose and 8.0 mL of 20 wt% sodium hydroxide aqueous solution. Then purge with nitrogen for protection and heat the reaction vessel to 80 °C. Keep it at this temperature and stir for 2.5 h. After stirring is complete, filter the filter cake and dry it to obtain copper-tin multiphase composite particles.

[0024] Step II: Preparation of silver-deposited copper-tin composite particles Weigh out 15.0g of copper-tin multiphase composite particles, 4.0g of silver nitrate, 4.0g of trisodium citrate dihydrate and 260.0mL of deionized water and add them to the reaction vessel. Stir and mix evenly. Then control the temperature of the reaction vessel at 30℃ and keep it warm and stirring for 0.5h. After stirring, filter the filter cake and dry it to obtain silver-deposited copper-tin composite particles.

[0025] The reaction principle for preparing silver-deposited copper-tin composite particles is as follows: In an ethylene glycol-water mixed medium and under alkaline conditions, copper ions and stannous ions undergo synergistic reduction with the participation of glucose. The metallic copper generated in the system further couples and diffuses with the active tin component in situ, forming a copper-tin biphase framework with compositional gradient characteristics. Subsequently, after silver nitrate is introduced into the aqueous system, silver ions selectively deposit at active sites on the surface of the copper-tin framework. Trisodium citrate regulates the release state of silver ions and the interfacial nucleation behavior through coordination, so that the silver component gradually forms a continuous coating layer on the outer layer of the particles, thereby obtaining a silver-coated copper-tin gradient reaction nucleus.

[0026] The working principle of silver-deposited copper-tin composite particles in silver-based multi-element alloy powder is as follows: In this process, the copper-tin multiphase composite particles and silver-deposited copper-tin composite particles obtained in steps I and II are not merely introduced into the subsequent system as simple intermediates, but together constitute an important precursor for the evolution of the microstructure and the formation of the comprehensive properties of the final silver-based multi-element alloy powder. Among them, the copper-tin multiphase composite particles formed in step I under ethylene glycol-water mixed medium, alkaline conditions and with the participation of glucose pre-establish the close contact relationship and local composition gradient between the copper component, the tin component and their reaction phases, so that copper and tin no longer exist in isolation, but enter the subsequent process as composite reaction nuclei with interfacial coupling characteristics, thereby shortening the diffusion path in the subsequent thermal conversion and alloying process and reducing the tendency of local component segregation and asynchronous phase transformation. Building upon this foundation, step II selectively deposits silver nitrate at active sites on the surface of copper-tin composite particles. By leveraging trisodium citrate to regulate the release state of silver ions and the nucleation behavior at the interface, silver components are preferentially distributed on the outer layer of the particles, forming gradient composite particles with the characteristics of a "copper-tin reaction nucleus-silver deposition layer." This structure prevents the silver component from randomly participating in the formation of subsequent silver-based multi-element alloy powders as independent particles. Instead, it participates in diffusion, rearrangement, and microstructure reconstruction in an interface layer pre-coupled with the copper-tin nucleus. This improves the spatial uniformity of the components in the final material, the coordination of interface transitions, and the consistency of thermal response, thereby reducing local fluctuations during melting, concentrating the melting transformation, and narrowing the melting temperature range. Simultaneously, these gradient composite particles also improve the reception, transition, and connectivity of the molten liquid phase during brazing, enhancing the continuous spreading ability of the liquid phase along the surface of the base material and in the gap region, thus increasing the spreading coefficient. Furthermore, this provides a more favorable structural basis for the compactness of the brazed joint structure, the integrity of the interface bonding, the joint strength, and the low helium leakage rate of the sealing structure.

[0027] Example 2 This embodiment provides a method for preparing silver-deposited copper-tin composite particles, including the following steps: Step I: Preparation of copper-tin multiphase composite particles Weigh out 14.0 g of copper sulfate pentahydrate, 24.0 g of stannous chloride dihydrate, 300.0 mL of ethylene glycol, and 120.0 mL of deionized water and add them to a reaction vessel. Stir and mix thoroughly. Then add 20.0 g of glucose and 15.0 mL of 25 wt% sodium hydroxide aqueous solution. Then purge with nitrogen for protection and heat the reaction vessel to 88 °C. Keep it at this temperature and stir for 3.5 h. After stirring is complete, filter the mixture, collect the filter cake, and dry it to obtain copper-tin multiphase composite particles.

[0028] Step II: Preparation of silver-deposited copper-tin composite particles Weigh out 18.0g of copper-tin multiphase composite particles, 6.0g of silver nitrate, 5.0g of trisodium citrate dihydrate and 320.0mL of deionized water and add them to the reaction vessel. Stir and mix evenly. Then control the temperature of the reaction vessel at 35℃ and keep it warm and stirring for 1h. After stirring, filter the filter cake and dry it to obtain silver-deposited copper-tin composite particles.

[0029] Example 3 This embodiment provides a method for preparing silver-deposited copper-tin composite particles, including the following steps: Step I: Preparation of copper-tin multiphase composite particles Weigh out 12.0 g of copper sulfate pentahydrate, 21.0 g of stannous chloride dihydrate, 270.0 mL of ethylene glycol, and 100.0 mL of deionized water and add them to a reaction vessel. Stir and mix thoroughly. Then add 18.0 g of glucose and 12.0 mL of 21 wt% sodium hydroxide aqueous solution. Then purge with nitrogen for protection and heat the reaction vessel to 85 °C. Keep it at this temperature and stir for 3.0 h. After stirring is complete, filter the filter cake and dry it to obtain copper-tin multiphase composite particles.

[0030] Step II: Preparation of silver-deposited copper-tin composite particles Weigh out 16.0g of copper-tin multiphase composite particles, 5.0g of silver nitrate, 4.5g of trisodium citrate dihydrate and 270.0mL of deionized water and add them to the reaction vessel. Stir and mix evenly. Then control the temperature of the reaction vessel at 35℃ and keep it at this temperature for 1 hour. After stirring, filter the filter cake and dry it to obtain silver-deposited copper-tin composite particles.

[0031] Example 4 This embodiment provides a method for preparing a silver-supported copper-zinc-tin sheet precursor, including the following steps: Step ①: Preparation of copper-zinc-tin sheet-like basic precursor Weigh out 6.0 g of copper sulfate pentahydrate, 3.0 g of zinc chloride, 4.0 g of stannous chloride dihydrate and 220.0 mL of deionized water and add them to the reaction vessel. Stir and mix well. Then add 45.0 mL of 10 wt% sodium carbonate aqueous solution. Heat the reaction vessel to 40 °C and keep it at this temperature for 1.5 h. After stirring, filter the filter cake and dry it to obtain the copper-zinc-tin flake basic precursor.

[0032] Step 2: Preparation of silver-supported copper-zinc-tin sheet precursor Weigh out 12.0g of copper-zinc-tin flake basic precursor, 1.2g of silver acetate and 160.0mL of ethylene glycol and add them to the reaction vessel. Stir and mix well. Then, purge with nitrogen for protection. Heat the reaction vessel to 150℃ and keep it at that temperature for 2 hours. After stirring, filter the cake and dry it to obtain the silver-supported copper-zinc-tin flake precursor.

[0033] The reaction principle for preparing silver-supported copper-zinc-tin sheet precursors is as follows: In an aqueous system containing copper, zinc, and tin ions, sodium carbonate provides an alkaline environment and a source of carbonate ions, promoting the simultaneous hydrolysis, coordination, and co-deposition of the metal ions. Under mild thermal conditions, copper-zinc-tin basic complex salt lamellar crystals with layered ordered stacking characteristics are formed. Subsequently, in an ethylene glycol medium and an inert atmosphere, silver species in silver acetate are gradually transformed and deposited on the surface of the layered lamellar crystals through solvothermal action. A stable bond is formed between the silver component and the exposed metal-oxygen coordination structure in the substrate, thereby obtaining a copper-zinc-tin layered composite sheet with silver component loaded on the surface.

[0034] The working principle of silver-loaded copper-zinc-tin flake precursors in silver-based multi-element alloy powder is as follows: In this process, the copper-zinc-tin sheet-like basic precursors and silver-loaded copper-zinc-tin sheet-like precursors obtained in steps ① and ② are not merely transitional intermediates, but together constitute important sheet-like functional units in the process of forming the final silver-based multi-element alloy powder hierarchical structure and comprehensive performance. In step ①, copper, zinc, and tin ions undergo simultaneous hydrolysis, coordination, and co-deposition in the alkaline and carbonate environment provided by sodium carbonate, and form a copper-zinc-tin sheet-like basic precursor with layered ordered stacking characteristics under mild thermal conditions. This allows multiple metal components to establish a stable spatial arrangement relationship with large surface contact and regular lamellar morphology in advance, thereby providing a sheet-like substrate with interface extension capability and path guiding characteristics for the subsequent system. Based on this, in step ②, silver acetate is gradually transformed and deposited on the surface of the lamellar precursor under ethylene glycol medium, nitrogen protection, and solvothermal conditions. This causes the silver component to no longer exist in the form of free particles, but rather in a surface-loaded state combined with the copper-zinc-tin layered substrate, entering the subsequent silver-based multi-element alloy powder formation process. As a result, the lamellar unit has both the interfacial development characteristics of the layered skeleton and the surface activity characteristics of the silver component. After this type of structure enters the subsequent system, it is beneficial to enhance the continuous contact state and response coordination of different components during thermal transformation, liquid phase generation, and interfacial migration. It promotes the continuous extension and stable filling of the molten liquid phase along the surface and gap regions of the base material, thereby improving the concentration of melting transformation, reducing the melting temperature range, and improving the spreading coefficient. At the same time, it can also provide a more favorable structural basis for the continuous formation of the brazing structure, the complete transition of the interfacial bonding, and the joint strength and low helium leakage rate.

[0035] Example 5 This embodiment provides a method for preparing a silver-supported copper-zinc-tin sheet precursor, including the following steps: Step ①: Preparation of copper-zinc-tin sheet-like basic precursor Weigh out 8.0 g of copper sulfate pentahydrate, 4.0 g of zinc chloride, 5.0 g of stannous chloride dihydrate and 280.0 mL of deionized water and add them to the reaction vessel. Stir and mix well. Then add 65.0 mL of 15 wt% sodium carbonate aqueous solution. Heat the reaction vessel to 45 °C and keep it at this temperature for 2 hours. After stirring, filter the filter cake and dry it to obtain the copper-zinc-tin flake basic precursor.

[0036] Step 2: Preparation of silver-supported copper-zinc-tin sheet precursor Weigh out 16.0g of copper-zinc-tin flake basic precursor, 1.8g of silver acetate and 220.0mL of ethylene glycol and add them to the reaction vessel. Stir and mix well. Then, purge with nitrogen for protection. Heat the reaction vessel to 165℃ and keep it at that temperature for 3 hours. After stirring, filter the cake and dry it to obtain the silver-supported copper-zinc-tin flake precursor.

[0037] Example 6 This embodiment provides a method for preparing a silver-supported copper-zinc-tin sheet precursor, including the following steps: Step ①: Preparation of copper-zinc-tin sheet-like basic precursor Weigh out 7.0 g of copper sulfate pentahydrate, 3.5 g of zinc chloride, 4.5 g of stannous chloride dihydrate and 250.0 mL of deionized water and add them to the reaction vessel. Stir and mix well. Then add 55.0 mL of 12 wt% sodium carbonate aqueous solution. Heat the reaction vessel to 45 °C and keep it at this temperature for 2 hours. After stirring, filter the filter cake and dry it to obtain the copper-zinc-tin flake basic precursor.

[0038] Step 2: Preparation of silver-supported copper-zinc-tin sheet precursor Weigh out 15.0g of copper-zinc-tin flake basic precursor, 1.5g of silver acetate and 180.0mL of ethylene glycol and add them to the reaction vessel. Stir and mix well. Then, purge with nitrogen for protection. Heat the reaction vessel to 155℃ and keep it at that temperature for 3 hours. After stirring, filter the cake and dry it to obtain the silver-supported copper-zinc-tin flake precursor.

[0039] Example 7 This embodiment provides a method for preparing a silver-based alloy material, including the following steps: Step 1: Preparation of cerium-silver-copper-tin composite particles Weigh out 0.8g of cerium nitrate hexahydrate, 2.8g of silver acetate, 1.6g of copper nitrate trihydrate, and 1.6g of stannous sulfate and mix them to obtain a mixed metal salt; Weigh out 6.0g of mixed metal salt, 8.0g of citric acid, 90.0mL of ethylene glycol and 50.0mL of deionized water and add them to the reaction vessel. Stir and mix evenly. Then heat to 75℃ and stir for 45min. Then heat to 125℃ and hold for 1h. Then continue to heat to 240℃ and hold for 20min. After heating is complete, a mixed atmosphere of hydrogen and nitrogen in a volume ratio of 1:19 is introduced. Then heat the reaction vessel to 300℃ and hold for 0.75h. After cooling, grind through a 200-mesh sieve to obtain cerium-silver-copper-tin composite particles.

[0040] The reaction principle for preparing cerium-silver-copper-tin composite particles is as follows: In an ethylene glycol-water mixed medium, cerium, silver, copper, and tin precursor salts are dissolved to form a multi-metal ion coexistence system. Citric acid regulates the complexation state of each metal component and the chemical environment of the solution through coordination, enabling different metal species to undergo simultaneous condensation, thermal decomposition, and short-range assembly during heating. As the temperature further increases, the system gradually transforms from a molecular-scale coordination structure into a composite inorganic phase containing silver, copper, and tin, with the cerium component participating in the process in the form of doping or local coordination. Under a hydrogen-nitrogen mixed atmosphere and at higher temperatures, the metal precursors undergo further reduction, removal of volatile ligands, and atomic diffusion, ultimately forming a cerium-containing silver-copper-tin nanoscale cluster structure.

[0041] The working principle of cerium-containing silver-copper-tin composite particles in silver-based multi-element alloy powder is as follows: In this process, the cerium-silver-copper-tin composite particles obtained in step one are not merely incorporated into the final system as conventional supplementary components, but rather participate in the structural construction and performance formation of the final silver-based multi-element alloy powder as composite particles with interface regulation and local microstructure coordination functions. Specifically, after the cerium, silver, copper, and tin precursor salts are coordinated by citric acid in an ethylene glycol-water mixed medium, a uniform chemical environment for the close coexistence of multiple metal ions is first established, enabling different metal species to have a high degree of proximity at the molecular scale. Subsequently, during the staged heating process, each metal component undergoes synchronous condensation, thermal decomposition, inorganic phase transformation, and close assembly, causing silver, copper, and tin to gradually transform from a dispersed precursor state into a closely related composite structure, while the cerium component is embedded in it through doping, local coordination, or interface distribution. Further, under a hydrogen-nitrogen mixed atmosphere and at higher temperatures, the system undergoes deep reduction, removal of volatile components, and atomic diffusion rearrangement, ultimately forming cerium-silver-copper-tin composite particles with nanoscale cluster characteristics. When these particles enter the subsequent silver-based multi-element alloy powder system, the cerium component is no longer randomly dispersed in an independent additive state, but participates in the subsequent powder construction, thermal transformation, and melt alloying process in a composite state pre-coupled with silver, copper, and tin. This is beneficial for enhancing the interfacial compatibility, smoothness of microstructure transition, and coordination of thermal response between different metal components, reducing local fluctuations and phase transformation rhythm mismatch during the melting process, and thus improving the concentration of melting transformation and reducing the melting temperature range. At the same time, it can also improve the stable acceptance and continuous connection of the molten liquid phase in the interfacial region, promote brazing filler metal spreading and gap filling, and provide a more favorable structural basis for the densification of the brazing joint microstructure, the integrity of the interfacial bonding, the improvement of joint strength, and the low helium leakage rate.

[0042] Step 2: Preparation of silver-copper-tin-zinc composite precursor powder Weigh out 45.0g of silver acetate, 24.0g of copper nitrate trihydrate, 6.0g of stannous sulfate and 5.0g of zinc nitrate hexahydrate and mix them to obtain a metal source; Weigh out 40.0g of metal source, 70.0mL of ethylene glycol and 100.0mL of deionized water and add them to the reaction vessel. Stir and mix well. Then add 6.0g of citric acid and 3.0g of sodium formate. Heat the reaction vessel to 58℃ and keep it at that temperature for 1.5h. After stirring, filter the cake and dry it to obtain silver-copper-tin-zinc composite precursor powder.

[0043] Step 3: Preparation of silver-based multi-component composite precursor powder Weigh out 100.0g of silver-copper-tin-zinc composite precursor powder, 1.5g of silver-deposited copper-tin composite particles prepared in Example 1, 0.5g of silver-loaded copper-zinc-tin flake precursor prepared in Example 4, 0.3g of cerium-containing silver-copper-tin composite particles, 4.0g of tris(hydroxymethyl)aminomethane, 100.0mL of anhydrous ethanol and 200.0mL of deionized water and add them to the reaction vessel and stir. After mixing evenly, add 2.0g of dopamine hydrochloride and keep the reaction vessel at 25℃ for 4h. After stirring, filter the cake and dry it to obtain silver-based multi-component composite precursor powder.

[0044] Step 4: Preparation of silver-based multi-element alloy powder Weigh 100.0g of silver-based multi-component composite precursor powder and place it in a tube furnace. After purging with nitrogen, heat the furnace to 360℃ and simultaneously introduce 12.0mL of vapor obtained from the evaporation of formic acid. Hold the temperature for 0.75h. Then switch to mixing hydrogen and nitrogen at a volume ratio of 2:23 to obtain a mixed gas. Heat the mixture to 500℃ and hold for 0.5h. After cooling, grind the mixture through a 200-mesh sieve to obtain silver-based multi-component alloy powder.

[0045] Step 5: Preparation of silver-based alloy materials Weigh out 3.0g of polyvinyl butyral and mix with 50.0mL of anhydrous ethanol to obtain the adhesive solution; Weigh out 20 parts by weight of silver-based multi-element alloy powder and 5 parts by weight of binder liquid, add them to a mixing tank, mix evenly to obtain a wet mixture, load the wet mixture into a mold, press it into a sheet blank with a thickness of 0.15 mm under a pressure of 100 MPa, then place it in an 80℃ forced-air drying oven for 40 min, and then transfer it to a vacuum furnace for 3×10 -2 The temperature was raised to 300℃ under Pa conditions and held for 30 minutes. After cooling, a silver-based alloy material was obtained.

[0046] The reaction principle for preparing silver-based alloy materials is as follows: In an ethylene glycol-water mixed medium, the multi-metal ions provided by silver acetate, copper nitrate, stannous sulfate, and zinc nitrate are in a relatively homogeneous chemical environment under the coordination of citric acid and the participation of formate. Complexation, partial hydrolysis, and initial reduction occur within the system, forming a highly dispersed homogeneous precursor phase of silver, copper, tin, and zinc components. Under weakly alkaline conditions maintained by Tris, dopamine undergoes oxidative self-polymerization and coordinates, adsorbs, and associates with the precursor powder and introduced silver-deposited copper-tin composite particles, silver-loaded copper-zinc-tin lamellar precursors, and cerium-containing silver-copper-tin composite particles, allowing components of different scales to be embedded in the same composite precursor system. After heat treatment in an inert atmosphere, formic acid vapor, and a hydrogen-nitrogen mixed atmosphere, the components are further reduced, deoxidized, diffused, and alloyed to form a silver-based multi-element alloy powder. Subsequently, after mixing with a binder, pressing, drying, and removing organic matter by vacuum heating, the interparticle contact and interfacial connection are enhanced, ultimately yielding a silver-based alloy material with a relatively continuous structure.

[0047] Example 8 This embodiment provides a method for preparing a silver-based alloy material, including the following steps: Step 1: Preparation of cerium-silver-copper-tin composite particles Weigh out 1.2g of cerium nitrate hexahydrate, 4.0g of silver acetate, 2.4g of copper nitrate trihydrate, and 2.5g of stannous sulfate and mix them to obtain a mixed metal salt; Weigh out 10.0g of mixed metal salt, 12.0g of citric acid, 120.0mL of ethylene glycol and 80.0mL of deionized water and add them to the reaction vessel. Stir and mix evenly. Then heat to 85℃ and stir for 60min. Then heat to 135℃ and hold for 1.5h. Then continue to heat to 270℃ and hold for 40min. After heating is complete, a mixed atmosphere of hydrogen and nitrogen in a volume ratio of 2:26 is introduced. Then heat the reaction vessel to 330℃ and hold for 1h. After cooling, grind through a 300-mesh sieve to obtain cerium-silver-copper-tin composite particles.

[0048] Step 2: Preparation of silver-copper-tin-zinc composite precursor powder Weigh out 52.0g of silver acetate, 32.0g of copper nitrate trihydrate, 8.0g of stannous sulfate and 7.0g of zinc nitrate hexahydrate and mix them to obtain a metal source; Weigh out 50.0g of metal source, 90.0mL of ethylene glycol and 100.0mL of deionized water and add them to the reaction vessel. Stir and mix well. Then add 9.0g of citric acid and 5.0g of sodium formate. Heat the reaction vessel to 65℃ and keep it at that temperature for 2.5h. After stirring, filter the cake and dry it to obtain silver-copper-tin-zinc composite precursor powder.

[0049] Step 3: Preparation of silver-based multi-component composite precursor powder Weigh out 100.0g of silver-copper-tin-zinc composite precursor powder, 2.5g of silver-deposited copper-tin composite particles prepared in Example 2, 1.0g of silver-loaded copper-zinc-tin flake precursor prepared in Example 5, 0.5g of cerium-containing silver-copper-tin composite particles, 7.0g of tris(hydroxymethyl)aminomethane, 100.0mL of anhydrous ethanol and 200.0mL of deionized water and add them to the reaction vessel and stir. After mixing evenly, add 2.0g of dopamine hydrochloride and keep the reaction vessel at 32℃ for 6h. After stirring, filter the cake and dry it to obtain silver-based multi-component composite precursor powder.

[0050] Step 4: Preparation of silver-based multi-element alloy powder Weigh 100.0g of silver-based multi-component composite precursor powder and place it in a tube furnace. After purging with nitrogen, heat the furnace to 390℃ and simultaneously introduce 15.0mL of vapor obtained from the evaporation of formic acid. Hold the furnace for 1 hour, then switch to mixing hydrogen and nitrogen in a volume ratio of 1:12 to obtain a mixed gas. Heat the mixed gas to 540℃ and hold for 0.75 hours. After cooling, grind the powder through a 300-mesh sieve to obtain silver-based multi-component alloy powder.

[0051] Step 5: Preparation of silver-based alloy materials Weigh out 4.0g of polyvinyl butyral and mix with 50.0mL of anhydrous ethanol to obtain the adhesive solution; Weigh out 20 parts by weight of silver-based multi-element alloy powder and 5 parts by weight of binder liquid, add them to a mixing tank, mix evenly to obtain a wet mixture, load the wet mixture into a mold, press it into a sheet blank with a thickness of 0.15 mm under a pressure of 100 MPa, then place it in an 80℃ forced-air drying oven for 40 min, and then transfer it to a vacuum furnace for 3×10 -2 The temperature was raised to 300℃ under Pa conditions and held for 30 minutes. After cooling, a silver-based alloy material was obtained.

[0052] Example 9 This embodiment provides a method for preparing a silver-based alloy material, including the following steps: Step 1: Preparation of cerium-silver-copper-tin composite particles Weigh out 1.0g of cerium nitrate hexahydrate, 3.2g of silver acetate, 2.0g of copper nitrate trihydrate, and 2.0g of stannous sulfate and mix them to obtain a mixed metal salt; Weigh out 8.0g of mixed metal salt, 10.0g of citric acid, 100.0mL of ethylene glycol and 60.0mL of deionized water and add them to the reaction vessel. Stir and mix evenly. Then heat to 80℃ and stir for 60min. Then heat to 130℃ and hold for 1.2h. Then continue to heat to 250℃ and hold for 30min. After heating is complete, a mixed atmosphere of hydrogen and nitrogen in a volume ratio of 3:47 is introduced. Then heat the reaction vessel to 320℃ and hold for 1h. After cooling, grind through a 250-mesh sieve to obtain cerium-silver-copper-tin composite particles.

[0053] Step 2: Preparation of silver-copper-tin-zinc composite precursor powder Weigh out 50.0g silver acetate, 28.0g copper nitrate trihydrate, 7.0g stannous sulfate and 6.0g zinc nitrate hexahydrate and mix them to obtain a metal source; Weigh out 45.0g of metal source, 80.0mL of ethylene glycol and 100.0mL of deionized water and add them to the reaction vessel. Stir and mix well. Then add 7.0g of citric acid and 4.0g of sodium formate. Heat the reaction vessel to 60℃ and keep it at that temperature for 2.0h. After stirring, filter the cake and dry it to obtain silver-copper-tin-zinc composite precursor powder.

[0054] Step 3: Preparation of silver-based multi-component composite precursor powder Weigh out 100.0g of silver-copper-tin-zinc composite precursor powder, 2.0g of silver-deposited copper-tin composite particles prepared in Example 3, 0.8g of silver-loaded copper-zinc-tin flake precursor prepared in Example 6, 0.4g of cerium-containing silver-copper-tin composite particles, 6.0g of tris(hydroxymethyl)aminomethane, 100.0mL of anhydrous ethanol and 200.0mL of deionized water and add them to the reaction vessel and stir. After mixing evenly, add 2.0g of dopamine hydrochloride and keep the reaction vessel at 30℃ for 5h. After stirring, filter the cake and dry it to obtain silver-based multi-component composite precursor powder.

[0055] Step 4: Preparation of silver-based multi-element alloy powder Weigh 100.0g of silver-based multi-component composite precursor powder and place it in a tube furnace. After purging with nitrogen, heat the furnace to 380℃. Simultaneously, introduce 13.5mL of vapor obtained from the evaporation of formic acid and keep it at that temperature for 1 hour. Then, switch to mixing hydrogen and nitrogen at a volume ratio of 1:23 to obtain a mixed gas. Heat the mixture to 520℃ and keep it at that temperature for 0.6 hours. After cooling, grind the mixture through a 250-mesh sieve to obtain silver-based multi-component alloy powder.

[0056] Step 5: Preparation of silver-based alloy materials Weigh out 3.5g of polyvinyl butyral and mix with 50.0mL of anhydrous ethanol to obtain the adhesive solution; Weigh out 20 parts by weight of silver-based multi-element alloy powder and 5 parts by weight of binder liquid, add them to a mixing tank, mix evenly to obtain a wet mixture, load the wet mixture into a mold, press it into a sheet blank with a thickness of 0.15 mm under a pressure of 100 MPa, then place it in an 80℃ forced-air drying oven for 40 min, and then transfer it to a vacuum furnace for 3×10 -2 The temperature was raised to 300℃ under Pa conditions and held for 30 minutes. After cooling, a silver-based alloy material was obtained.

[0057] Comparative Example 1 The difference between this comparative example and Example 9 is that the use of silver-deposited copper-tin composite particles was omitted in step three, and silver-copper-tin-zinc composite precursor powder was used as an equal substitute.

[0058] Comparative Example 2 The difference between this comparative example and Example 9 is that in step three, the silver-loaded copper-zinc-tin sheet precursor is omitted, and an equal amount of silver-copper-tin-zinc composite precursor powder is used instead.

[0059] Comparative Example 3 The difference between this comparative example and Example 9 is that the use of cerium-containing silver-copper-tin composite particles was omitted in step three, and an equal amount of silver-copper-tin-zinc composite precursor powder was used instead.

[0060] Performance testing: Oxygen-free copper plates and iron-nickel-cobalt low-expansion sealing alloy plates were selected as base materials and processed into test pieces with dimensions of 50mm×10mm×2mm. The overlap length was controlled to be 5mm. Before welding, the surfaces to be welded were first polished with 800-grit silicon carbide sandpaper, and then ultrasonically cleaned in acetone and anhydrous ethanol for 10 minutes each. Afterward, they were dried in a 90℃ forced-air drying oven for 20 minutes. During assembly, a rectangular silver-based alloy material with a thickness of 0.15mm, matching the size of the overlap area, was placed in the center of the overlap area, and a 0.05mm thick stainless steel shim was used to control the joint gap. Then, a graphite clamp was used for positioning and fixing. Finally, the assembled test piece was placed in a vacuum brazing furnace and evacuated to a vacuum of 3.0×10. -3 Pa, the temperature is increased to 200℃ at 8℃ / min and held for 20min, then increased to 380℃ at 5℃ / min and held for 20min to further remove residual organic matter and degas. Then the temperature is increased to 760℃ at 6℃ / min and held for 6min to complete the brazing. After the holding period, the temperature is cooled to below 300℃ in the furnace and removed from the furnace to obtain the lap brazed sample. A sealing cavity was assembled using a low-expansion iron-nickel-cobalt (FeNiCo) alloy ring, an upper cover plate, and a lower base plate. The ring measures 20mm outer diameter, 14mm inner diameter, and 3mm height. The upper cover plate and lower base plate are both 20mm in diameter and 2mm thick. Before welding, the upper and lower end faces of the ring, as well as the surfaces of the cover plate and base plate to be welded, were polished with 800-grit silicon carbide sandpaper. They were then ultrasonically cleaned in acetone and anhydrous ethanol for 10 minutes each, followed by drying in a 90℃ forced-air drying oven for 20 minutes. During assembly, a 0.15mm thick ring-shaped silver-based alloy material matching the ring structure was placed between the ring and the upper cover plate, and between the ring and the lower base plate, with an assembly gap controlled at 0.04mm. Graphite fixtures were used for positioning and clamping. The assembled sealing cavity sample was placed in a vacuum brazing furnace and evacuated to a vacuum level of 3.0×10⁻⁶. -3 Pa, the temperature is increased to 200℃ at 8℃ / min and held for 20min, then increased to 380℃ at 5℃ / min and held for 20min to further remove residual organic matter and degas. Then the temperature is increased to 760℃ at 6℃ / min and held for 6min to complete the brazing. After the holding period, the temperature is cooled to below 300℃ in the furnace and removed from the furnace to obtain a sealed cavity sample. The melting temperature ranges of the silver-based alloy materials prepared in Examples 7-9 and Comparative Examples 1-3 were tested in accordance with the standard GB / T 1425-2021 "Determination of Melting Temperature Range of Precious Metals and Their Alloys - Thermal Analysis Test Method". The spreadability coefficients of the silver-based alloy materials prepared using Examples 7-9 and Comparative Examples 1-3 were tested in accordance with the standard GB / T 11364-2008 "Test Method for Wettability of Brazing Alloy". The brazed joint strength of the lap brazed specimens obtained by brazing silver-based alloy materials prepared in Examples 7-9 and Comparative Examples 1-3 was tested in accordance with the standard GB / T 11363-2008 "Test Method for Brazed Joint Strength". The sealing performance of the sealed cavity samples obtained by brazing silver-based alloy materials prepared in Examples 7-9 and Comparative Examples 1-3 was tested in accordance with the standard GB / T 32218-2015 "Vacuum Technology - Test Method for Leakage Rate of Vacuum Systems". See Table 1 for specific data; Table 1 - Performance Test Data for Each Sample

[0061] Data Analysis: Comparative analysis of the data in Table 1 reveals that the silver-based alloy material prepared in this invention has a melting temperature range of 25.7°C and a spread factor of 0.86. Furthermore, the tensile strength of the lap-welded specimen obtained using this silver-based alloy material is 188 N·mm².-2 The shear strength is 234 N·mm. -2 The helium leakage rate of the sealed cavity sample obtained by brazing was 3.6 × 10⁻⁶. -10 (Pa·m 3 )·s -1 All data points are better than the comparative data, indicating that: In Comparative Example 1, silver-deposited copper-tin composite particles were not introduced in step three, which weakened the transition configuration of the particle-level heterogeneous components in the system. The original hierarchical overlap relationship between the basic precursor powder and the lamellar components was difficult to fully establish. As a result, during the heating transformation and subsequent brazing process, the local connection and continuous diffusion path between particles tended to be simple, the degree of synergistic response between different components decreased, and the acceptance, transition and connectivity of the liquid phase in the local area during the melting stage were more likely to be uneven. This affected the concentration of melting transformation and the continuity of the structure and the integrity of the interface during the brazing process, which weakened the overall matching relationship of the material during melting, spreading and forming the joint, and manifested as an increase in the melting temperature range, a decrease in the spreading coefficient and a decrease in joint strength and sealing performance. In Comparative Example 2, the silver-loaded copper-zinc-tin sheet precursor was not introduced in step three, causing the system to lose the interfacial extension basis and path guiding role of the sheet components in spatial arrangement. The organizational framework jointly constructed by the particulate components and sheet components was no longer complete. Under these conditions, during the heating transformation, melting operation and brazing process, the material exhibited more local contact and diffusion between particles. The continuous spreading conditions and transformation basis brought about by the original large contact interface were difficult to form. As a result, after the material entered the melting stage, the migration, edge extension and local filling of the liquid phase along the surface of the base material and narrow gaps were more likely to be uneven. This affected the concentration, coverage uniformity, seam continuity and subsequent organizational coordination of the melting transformation, and manifested as an increase in the melting temperature range, a decrease in the spreading coefficient and a decrease in the mechanical properties and sealing reliability of the joint. In Comparative Example 3, cerium-silver-copper-tin composite particles were not introduced in step three, resulting in the absence of a regulating unit in the system for coordinating the transition relationship between heterogeneous components. The composite interface between granular components, plate-like components and matrix precursor powder was more difficult to maintain a smooth and continuous evolution state. Consequently, during the subsequent reduction, alloying and brazing thermal cycles, there was a lack of necessary buffering and connection between the local reaction rhythm of different components and the microstructure transformation behavior. The interface area was more prone to uneven transition and local weak points. Furthermore, the weakening of this microstructure coordination ability would reduce the consistency of the thermal response of the material during the melting stage, and make it difficult to maintain the coordinated and consistent state of the joint structure, interface connection and load transfer path after the joint is formed, thereby affecting the overall stability of the material system, which is manifested as an increase in the melting temperature range, a decrease in joint strength and an increase in helium leakage rate. In conclusion, the functional components in this application are not independent and interchangeable parallel entities. Instead, they participate in different levels of structural organization and performance regulation during the construction of composite precursor powder, heat treatment conversion, and brazing. Among them, the particle-level components mainly affect the contact connection, local transition, and liquid connection state between components; the plate-like components are mainly related to interface extension, continuous spreading path, and seam formation; and the cerium-containing components further affect the evolution rhythm of heterogeneous interfaces, the coordination state of the structure, and the defect suppression ability. When any of the aforementioned components is missing, although the system can still complete the basic process, the correspondence between the material in melting transformation, liquid phase migration, local filling, structural transition, and joint formation tends to weaken. Specifically, the performance indicators such as melting temperature range, spreading coefficient, joint strength, and helium leakage rate all deteriorate to varying degrees.

[0062] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

[0063] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0064] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A silver-based alloy material, characterized in that, The silver-based alloy material comprises a silver-based alloy structure formed by thermal conversion of silver-based multi-element alloy powder. The silver-based multi-element alloy powder comprises Ag, Cu, Sn, Zn and Ce components, wherein Ag is the matrix component, Cu, Sn and Zn are the main alloying components, and Ce is the modifying component. The silver-based alloy material is prepared by mixing silver-based multi-element alloy powder with binder, followed by pressing, drying, and pre-degreasing treatment. The silver-based multi-element alloy powder is prepared by heat treatment after forming a silver-based multi-element composite precursor powder from silver-copper-tin-zinc composite precursor powder, silver-deposited copper-tin composite particles, silver-loaded copper-zinc-tin flake precursor, and cerium-containing silver-copper-tin composite particles under the action of tris(hydroxymethyl)aminomethane and dopamine hydrochloride.

2. The silver-based alloy material according to claim 1, characterized in that, The preparation method of the silver-based multi-component composite precursor powder is as follows: Weigh out the following according to the dosage ratio: 100g silver-copper-tin-zinc composite precursor powder, 1.5-2.5g silver-deposited copper-tin composite particles, 0.5-1.0g silver-loaded copper-zinc-tin flake precursor, 0.3-0.5g cerium-containing silver-copper-tin composite particles, 4-7g tris(hydroxymethyl)aminomethane, 100mL anhydrous ethanol and 200mL deionized water and add them to the reaction vessel and stir. After mixing evenly, add 2g dopamine hydrochloride and keep the reaction vessel temperature at 25-32℃ for 4-6 hours. After stirring, filter the cake and dry it to obtain the silver-based multi-component composite precursor powder.

3. The silver-based alloy material according to claim 1, characterized in that, The heat treatment is as follows: silver-based multi-component composite precursor powder is loaded into a tube furnace, nitrogen is introduced for purging, and the temperature is raised to 360-390℃. At the same time, vapor obtained from the evaporation of formic acid is introduced and the temperature is maintained for 0.75-1h. Then, the mixture is switched to a mixed gas and the temperature is raised to 500-540℃ and maintained for 0.5-0.75h. The ratio of silver-based multi-component composite precursor powder to formic acid is 100g:12-15mL, and the mixed gas is obtained by mixing hydrogen and nitrogen in a volume ratio of 1-2:23-24.

4. The silver-based alloy material according to claim 1, characterized in that, The preparation method of the silver-copper-tin-zinc composite precursor powder is as follows: Weigh 40-50g of metal source, 70-90mL of ethylene glycol and 100mL of deionized water according to the dosage ratio, add them to the reaction vessel and stir. After mixing evenly, add 6-9g of citric acid and 3-5g of sodium formate. Heat the reaction vessel to 58-65℃ and keep it at this temperature for 1.5-2.5h. After stirring, filter the cake and dry it to obtain the silver-copper-tin-zinc composite precursor powder. The metal source is obtained by mixing silver acetate, copper nitrate trihydrate, stannous sulfate and zinc nitrate hexahydrate in the dosage ratio of 45-52g:24-32g:6-8g:5-7g.

5. The silver-based alloy material according to claim 1, characterized in that, The preparation method of the cerium-silver-copper-tin composite particles is as follows: Weigh 6-10g of mixed metal salt, 8-12g of citric acid, 90-120mL of ethylene glycol and 50-80mL of deionized water according to the dosage ratio, add them to the reaction vessel and stir. After mixing evenly, heat to 75-85℃ and stir for 45-60min, then heat to 125-135℃ and hold for 1-1.5h, then continue to heat to 240-270℃ and hold for 20-40min. The post-treatment yields cerium-silver-copper-tin composite particles. The mixed metal salt is obtained by mixing cerium nitrate hexahydrate, silver acetate, copper nitrate trihydrate and stannous sulfate in a dosage ratio of 0.8-1.2g:2.8-4.0g:1.6-2.4g:1.6-2.5g.

6. The silver-based alloy material according to claim 1, characterized in that, The silver-deposited copper-tin composite particles were prepared by the following method: A1. Weigh out 10-14g of copper sulfate pentahydrate, 18-24g of stannous chloride dihydrate, 240-300mL of ethylene glycol, and 80-120mL of deionized water according to the dosage ratio. Add them to the reaction vessel and stir. After mixing evenly, add 14-20g of glucose and then 8-15mL of alkaline solution. Then, purge with nitrogen for protection and heat the reaction vessel to 80-88℃. Keep it at this temperature and stir for 2.5-3.5h. Post-treatment yields copper-tin multiphase composite particles. The alkaline solution is a 20-25wt% sodium hydroxide aqueous solution. A2. Weigh out 15-18g of copper-tin multiphase composite particles, 4-6g of silver nitrate, 4-5g of trisodium citrate dihydrate, and 260-320mL of deionized water according to the dosage ratio. Add them to the reaction vessel and stir. After mixing evenly, control the temperature of the reaction vessel at 30-35℃ and keep it warm while stirring for 0.5-1h. Post-processing yields silver-deposited copper-tin composite particles.

7. The silver-based alloy material according to claim 1, characterized in that, The silver-loaded copper-zinc-tin sheet precursor was prepared by the following method: B1. Weigh out 6-8g of copper sulfate pentahydrate, 3-4g of zinc chloride, 4-5g of stannous chloride dihydrate and 220-280mL of deionized water according to the dosage ratio. Add them to the reaction vessel and stir. After mixing evenly, add 45-65mL of regulator. Heat the reaction vessel to 40-45℃ and keep it at this temperature while stirring for 1.5-2 hours. Post-process to obtain copper-zinc-tin flake basic precursor. The regulator is 10-15wt% sodium carbonate aqueous solution. B2. Weigh out 6-8g of copper-zinc-tin flake basic precursor, 0.6-0.9g of silver acetate and 80-110mL of ethylene glycol according to the dosage ratio, add them to the reaction vessel and stir. After mixing evenly, purge with nitrogen gas for protection, then heat the reaction vessel to 150-165℃ and keep it at that temperature for 2-3 hours. Post-process to obtain silver-loaded copper-zinc-tin flake precursor.

8. A method for preparing a silver-based alloy material according to any one of claims 1-7, characterized in that, The process includes the following steps: Weigh 20 parts by weight of silver-based multi-element alloy powder and 5 parts by weight of binder liquid and add them to a mixing tank. After mixing evenly, a wet mixture is obtained. The wet mixture is then placed into a mold and pressed into a sheet blank with a thickness of 0.15 mm under a pressure of 100 MPa. Subsequently, it is placed in an 80℃ forced-air drying oven for 40 minutes and then transferred to a vacuum furnace for drying at 3×10⁻⁶ ℃. -2 The temperature is raised to 300℃ under Pa conditions and held for 30 min. After cooling, a silver-based alloy material is obtained. The binder is prepared by mixing polyvinyl butyral and anhydrous ethanol at a ratio of 3-4 g: 50 mL.

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