An antioxidant and low-temperature resistant solder material and its preparation method

Abstract

The present invention relates to an antioxidant and low-temperature-resistant solder material and a preparation method thereof, belonging to the technical field of low-temperature welding materials. The solder material is composed of the following components in weight percentage: 92-98.9 wt% of SnBi-based eutectic alloy, 0.1-1 wt% of XCl3@MXene, and 1-7 wt% of flux. The present invention also discloses a preparation method thereof: Step S1: Prepare MXene by chemical etching method; Step S2: In-situ synthesize XCl3@MXene; Step S3: Prepare XCl3@MXene-reinforced SnBi-based solder material by melting method or ball milling method. The SnBi-based solder prepared by the present invention has remarkable low-temperature resistance and can maintain good toughness and connection strength in extremely low-temperature environments. At the same time, the synergistic effect of MXene and rare earth chloride refines the microstructure of the solder, enhances the compatibility with different base materials, and greatly improves the mechanical properties, wettability, thermal stability and anti-aging properties of the solder. The preparation method is simple, efficient and low-cost, and is suitable for large-scale production.

Description

Technical Field

[0001] The present invention belongs to the field of electronic circuit soldering materials suitable for working under extremely cold conditions, and particularly relates to a circuit soldering tin solder material with antioxidant and low-temperature environment resistance and a preparation method thereof. Background Art

[0002] With the rapid development of modern electronic technology, the application fields of electronic products have been continuously broadened, especially for electronic circuits operating in extremely cold environments, which pose higher requirements for the low-temperature environment resistance of auxiliary materials for electronic circuit assembly and soldering. Tin-silver (SnAg) alloys are applied in the fields of electronic assembly and packaging due to their excellent electrical conductivity and antioxidant properties. Although pure tin (Sn) has good electrical conductivity, it is extremely easy to oxidize in the air, resulting in a reduction in the reliability of solder joints. To improve the antioxidant property, silver (Ag) is usually added. However, silver materials are expensive, increasing the production cost.

[0003] Tin-bismuth (SnBi) alloys have attracted much attention due to their low melting point and low cost. Especially the Sn58Bi eutectic alloy, whose melting point is only 138°C, has a similar microstructure and mechanical strength to SnPb alloys, so it has broad application prospects in the electronic field. However, SnBi alloys also have some problems that need to be solved urgently, such as poor plasticity of the alloy caused by the brittleness of the Bi phase, and interface embrittlement caused by the segregation of the Bi phase during the thermal aging of solder joints. These problems all affect the long-term service reliability of solder joints. To improve the properties of SnBi alloys, a large number of alloying studies have been carried out by adding different alloying elements to optimize the microstructure and properties of SnBi alloys. For example, adding elements such as Ag, Cu, Zn, and In can improve the melting point, wettability, microstructure, and mechanical properties of SnBi alloys to a certain extent.

[0004] In addition, Sn is prone to becoming brittle in a low-temperature environment, affecting its frost resistance. Whether it is SnAg alloy or SnBi alloy, Sn is one of the important components. When the temperature of Sn drops below 13.2°C, white Sn (βSn) will gradually transform into gray Sn (αSn). This transformation is an allotrope transformation. Gray Sn is powdery, its structure is a diamond-type cubic lattice, its relative density is less than that of white Sn, and it is loose and has low strength, making the original dense Sn products become fragile and lose their normal use performance.

[0005] The inventors found that rare earth chlorides of cerium (Ce) and lanthanum (La) can refine the grains of solder, improve the stability of the solder's microstructure, and thus enhance the low-temperature resistance of the solder. In a low-temperature environment, rare earth chlorides can inhibit the increase in brittleness of the solder and improve its toughness and impact resistance. Rare earth chlorides and MXene can also form a dense oxide film on the surface of the solder material, preventing the intrusion of oxygen and other corrosive media, and improving the oxidation resistance and corrosion resistance of the solder, which is of great significance for improving the long-term stability and reliability of the welded joints.

[0006] In recent years, the development of nanotechnology has provided new ideas for improving the properties of solder. By introducing nano-reinforcing phases, such as nanoparticles, nanowires, or nanosheets, the mechanical properties and reliability of solder can be effectively improved. Among them, MXene, as a new type of two-dimensional nanomaterial, has attracted much attention due to its excellent mechanical and electrical properties. Introducing MXene into SnBi-based solder materials is expected to further improve their mechanical properties and reliability. Combining rare earth chlorides with MXene to form a rare earth chloride@MXene composite nanostructure can not only exert the nano-reinforcement effect of MXene but also utilize the unique properties of rare earth chlorides to further improve the properties of SnBi-based solder. Summary of the Invention

[0007] The purpose of the present invention is to provide an antioxidant and low-temperature-resistant solder material and its preparation method. By introducing new materials such as rare earth chlorides and MXene, a solder material with low cost, excellent antioxidant and antifreeze properties is obtained to solve the problems of high cost and insufficient antifreeze performance of traditional solder materials. The solder material of the present invention not only has a low cost but also can maintain good physical and chemical stability in an extremely low-temperature environment, thus meeting the requirements of modern electronic products for high-performance welding materials.

[0008] Specifically, the present invention provides the following technical solutions:

[0009] An antioxidant and low-temperature-resistant solder material, the solder material comprising: 87 - 95 wt% of SnBi-based eutectic alloy, 0.1 - 10 wt% of rare earth-modified MXene, and 1 - 7 wt% of flux.

[0010] The SnBi-based eutectic alloy is one of Sn58Bi (42 wt% Sn, 58 wt% Bi), Sn58Bi0.5Ag (41.5 wt% Sn, 58 wt% Bi, 0.5 wt% Ag), Sn58Bi4Cu (38 wt% Sn, 58 wt% Bi, 4 wt% Cu), Sn58Bi0.5In (41.5 wt% Sn, 58 wt% Bi, 0.5 wt% In) and Sn58Bi3Zn (39 wt% Sn, 58 wt% Bi, 3 wt% Zn). The rare earth is one of La and Ce. The flux includes: 94 - 98 wt% rosin, 1 - 3 wt% active agent, and 0.5 - 3 wt% surfactant. The active agent is at least one of succinic acid, adipic acid, sebacic acid, lauric acid or triethanolamine. The surfactant is at least one of pentaerythritol oleate or polyethylene glycol 200.

[0011] The preparation process of the soldering material is completed according to the following steps: Step S1: Prepare MXene by chemical etching method; Step S2: In-situ synthesize XCl3@MXene; Step S3: Prepare XCl3@MXene reinforced soldering material by melting method or ball milling method.

[0012] The specific process of preparing MXene by chemical etching method in Step S1 is as follows: Add MAX phase powder into 40 wt% HF solution, then transfer it to a water bath at 40 °C and heat for 24 h. After the reaction, the precipitate is centrifugally washed with deionized water until the pH value is neutral, and finally dried in a vacuum drying oven at 60 °C for 24 h to obtain MXene powder.

[0013] X in Step S2 is one of Ce and La.

[0014] The specific process of in-situ synthesizing XCl3@MXene in Step S2 is as follows: Disperse the prepared MXene in deionized water to form a uniform suspension. Add X2(CO3)3 and sufficient HCl to the MXene suspension and stir continuously to make it react fully. After the reaction, the reaction product is centrifuged, washed and dried to obtain XCl3@MXene. The weight fraction ratio of MXene to X2(CO3)3 is 2:1 - 10.

[0015] The specific process of preparing XCl3@MXene reinforced soldering material by melting method in Step S3 is as follows: Ball mill and mix the SnBi-based eutectic alloy, rare earth modified MXene and flux under argon protection, and then melt in a melting furnace at a temperature of 150 - 250 °C for 15 - 30 min to obtain a composite soldering material.

[0016] In the step S3, the specific process of preparing the XCl3@MXene reinforced solder material by ball milling method is as follows: Add the SnBi-based eutectic alloy, rare earth modified MXene, and flux into a ball mill in a certain proportion. Fill the ball mill with argon gas and grind at a rotation speed of 2000 - 4000 r / min until the particle size of the solid particles is ≤40 μm, then the composite solder material can be obtained.

[0017] Advantages of the present invention:

[0018] (1) In the low-temperature resistant solder material of the present invention, Ce and La rare earth chlorides can refine the grain structure of the solder, improve the stability of the solder microstructure, inhibit the increase of brittleness, improve its toughness and impact resistance, thereby enhancing the low-temperature resistance of the solder material.

[0019] (2) The presence of Ce and La rare earth chlorides reduces the interfacial tension between the solder and the base material, improves the wettability of the solder, enables the solder to spread more evenly on the welding surface during the welding process, and improves the welding quality.

[0020] (3) Ce and La rare earth chlorides and MXene can also form a dense oxide film on the surface of the solder material, preventing the intrusion of oxygen and other corrosive media, and improving the oxidation resistance and corrosion resistance of the solder, which is of great significance for improving the long-term stability and reliability of the welded joint.

[0021] (4) As a new type of two-dimensional nanomaterial, MXene has excellent mechanical properties. Acting synergistically with Ce and La rare earth chlorides, it can significantly refine the microstructure of the SnBi-based solder material, reduce problems such as coarse microstructure and grain boundary segregation, thereby improving the mechanical property indexes such as the strength, hardness and fatigue resistance of the solder material, making the solder joint more difficult to break when subjected to external forces, and enhancing the stability of the welded structure.

[0022] (5) Ce and La rare earth chlorides and MXene do not exist in isolation in the solder material. There is a certain interaction between them. The rare earth chlorides can adsorb on the surface of MXene to form stable chemical bonding, thereby enhancing the stability and dispersion of MXene in the solder material. This synergistic effect not only improves the mechanical properties of the solder material, but also enables the solder material to have better thermal stability and anti-aging performance at low temperatures. Description of the drawings

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required in the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can also be obtained based on these drawings.

[0024] Figure 1 This is the preparation flow chart of the present invention. Specific embodiments

[0025] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions of the present invention in combination with the embodiments of the present invention. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention. The process parameters without specific conditions noted in the following embodiments are usually in accordance with conventional conditions. Example 1

[0026] An antioxidant and low-temperature-resistant solder material, the solder material comprising: 92 wt% of Sn58Bi eutectic alloy, 1 wt% of rare earth La-modified MXene, and 7 wt% of a flux, wherein the flux includes 98 wt% of rosin, 1 wt% of succinic acid activator, and 1 wt% of pentaerythritol oleate surfactant.

[0027] The preparation process of the solder material is completed according to the following steps: Step S1: Add MAX phase powder into 40 wt% HF solution, then transfer it to a 40°C water bath for heating and reacting for 24 h. After the reaction ends, the precipitate is centrifugally washed with deionized water until the pH value is neutral, and finally dried in a 60°C vacuum drying oven for 24 h to obtain MXene powder; Step S2: Disperse 2 parts of the prepared MXene in deionized water to form a uniform suspension. Add 1 part of La2(CO3)3 to the MXene suspension and continuously stir it with sufficient HCl to make it react fully. After the reaction ends, the reaction product is centrifuged, washed, and dried to obtain LaCl3@MXene; Step S3: Ball-mill and mix the Sn58Bi eutectic alloy, LaCl3@MXene, and flux under argon protection, and then melt them in a melting furnace at a temperature of 150°C for 15 min to obtain a composite solder material. Example 2

[0028] An antioxidant and low-temperature resistant solder material, the solder material comprising: 95 wt% of Sn58Bi0.5Ag (41.5 wt% Sn, 58 wt% Bi, 0.5 wt% Ag) eutectic alloy, 0.1 wt% of rare earth La modified MXene, 4.9 wt% of a soldering flux, wherein the soldering flux includes 94 wt% of rosin, 3 wt% of adipic acid activator, and 3 wt% of polyethylene glycol 200 surfactant.

[0029] The preparation process of the solder material is completed according to the following steps: Step S1: Add MAX phase powder into a 40 wt% HF solution, then transfer it to a water bath at 40 °C for heating and reacting for 24 h. After the reaction ends, the precipitate is centrifugally washed with deionized water until the pH value is neutral, and finally dried in a vacuum drying oven at 60 °C for 24 h to obtain MXene powder; Step S2: Disperse 2 parts of the prepared MXene in deionized water to form a uniform suspension. Add 3 parts of La2(CO3)3 and sufficient HCl to the MXene suspension and continuously stir to make it react fully. After the reaction ends, the reaction product is centrifuged, washed, and dried to obtain LaCl3@MXene; Step S3: Add the Sn58Bi0.5Ag eutectic alloy, LaCl3@MXene, and soldering flux into a ball mill in a certain proportion. Fill the ball mill with argon and grind it at a rotation speed of 3000 r / min until the particle size of the solid particles ≤ 40 μm, then the composite solder material can be obtained. Example 3

[0030] An antioxidant and low-temperature resistant solder material, the solder material comprising: 92.5 wt% of Sn58Bi4Cu (38 wt% Sn, 58 wt% Bi, 4 wt% Cu) eutectic alloy, 5 wt% of rare earth Ce modified MXene, 2.5 wt% of a soldering flux, wherein the soldering flux includes 96 wt% of rosin, 2 wt% of sebacic acid activator, and 2 wt% of polyethylene glycol 200 surfactant.

[0031] The preparation process of the solder material is completed according to the following steps: Step S1: Add MAX phase powder into 40wt% HF solution, then transfer it to a water bath at 40°C and heat for reaction for 24h. After the reaction ends, the precipitate is centrifugally washed with deionized water until the pH value is neutral, and finally dried in a vacuum drying oven at 60°C for 24h to obtain MXene powder; Step S2: Disperse 2 parts of the prepared MXene in deionized water to form a uniform suspension. Add 5 parts of Ce2(CO3)3 and sufficient HCl to the MXene suspension and continuously stir to make it react fully. After the reaction ends, the reaction product is centrifuged, washed, and dried to obtain CeCl3@MXene; Step S3: Ball-mill and mix the Sn58Bi4Cu eutectic alloy, CeCl3@MXene, and flux under argon protection, and then melt in a melting furnace at 250°C for 20min to obtain the composite solder material. Example 4

[0032] An antioxidant and low-temperature resistant solder material, the solder material comprises: 89wt% of Sn58Bi3Zn (39wt% Sn, 58wt% Bi, 3wt% Zn) eutectic alloy, 10wt% of rare earth Ce-modified MXene, and 1wt% of flux, wherein the flux includes 97wt% of rosin, 1wt% of lauric acid activator, and 2wt% of pentaerythritol oleate surfactant.

[0033] The preparation process of the solder material is completed according to the following steps: Step S1: Add MAX phase powder into 40wt% HF solution, then transfer it to a water bath at 40°C and heat for reaction for 24h. After the reaction ends, the precipitate is centrifugally washed with deionized water until the pH value is neutral, and finally dried in a vacuum drying oven at 60°C for 24h to obtain MXene powder; Step S2: Disperse 2 parts of the prepared MXene in deionized water to form a uniform suspension. Add 7 parts of Ce2(CO3)3 and sufficient HCl to the MXene suspension and continuously stir to make it react fully. After the reaction ends, the reaction product is centrifuged, washed, and dried to obtain CeCl3@MXene; Step S3: Add the Sn58Bi3Zn eutectic alloy, CeCl3@MXene, and flux to a ball mill in a certain proportion, fill the ball mill with argon, and grind at a rotation speed of 2000r / min until the particle size of the solid particles ≤ 40μm to obtain the composite solder material. Example 5

[0034] An antioxidant and low-temperature-resistant soldering material, the soldering material comprising: 87 wt% of Sn58Bi0.5In (41.5 wt% Sn, 58 wt% Bi, 0.5 wt% In) eutectic alloy, 7 wt% of rare-earth Ce-modified MXene, and 6 wt% of a soldering flux, wherein the soldering flux includes 98 wt% of rosin, 1 wt% of succinic acid activator, and 1 wt% of polyethylene glycol 200 surfactant.

[0035] The preparation process of the soldering material is completed according to the following steps: Step S1: Add MAX phase powder into 40 wt% HF solution, then transfer it to a 40°C water bath for heating and reacting for 24 h. After the reaction ends, the precipitate is centrifugally washed with deionized water until the pH value is neutral, and finally dried in a 60°C vacuum drying oven for 24 h to obtain MXene powder; Step S2: Disperse 2 parts of the prepared MXene in deionized water to form a uniform suspension. Add 10 parts of Ce2(CO3)3 to the MXene suspension and continuously stir it with sufficient HCl to fully react. After the reaction ends, the reaction product is centrifuged, washed, and dried to obtain CeCl3@MXene; Step S3: Ball-mill and mix the Sn58Bi0.5In eutectic alloy, CeCl3@MXene, and the soldering flux under argon protection, and then melt them in a melting furnace at a temperature of 180°C for 20 min to obtain the composite soldering material.

[0036] Comparative Example 1

[0037] A Sn58Bi soldering alloy, with the mass percentage of Sn being 42% and the mass percentage of Bi being 58%. This soldering alloy is a binary eutectic alloy with a melting point of 138°C.

[0038] Comparative Example 2

[0039] A soldering material, the soldering material comprising: 92 wt% of Sn58Bi eutectic alloy, 1 wt% of MXene, and 7 wt% of a soldering flux, wherein the soldering flux includes 98 wt% of rosin, 1 wt% of succinic acid activator, and 1 wt% of pentaerythritol oleate surfactant.

[0040] The preparation process of the soldering material is completed according to the following steps: Step S1: Add MAX phase powder into 40 wt% HF solution, then transfer it to a 40°C water bath for heating and reacting for 24 h. After the reaction ends, the precipitate is centrifugally washed with deionized water until the pH value is neutral, and finally dried in a 60°C vacuum drying oven for 24 h to obtain MXene powder; Step S2: Ball-mill and mix the Sn58Bi eutectic alloy, MXene, and the soldering flux under argon protection, and then melt them in a melting furnace at a temperature of 170°C for 15 min to obtain the composite soldering material.

[0041] Comparative Example 3

[0042] A soldering material, the soldering material comprising: 92 wt% of Sn58Bi eutectic alloy, 1 wt% of rare earth LaCl3, and 7 wt% of flux, wherein the flux includes 98 wt% of rosin, 1 wt% of succinic acid activator, and 1 wt% of pentaerythritol oleate surfactant.

[0043] The preparation process of the soldering material is completed according to the following steps: Step S1: Stir La2(CO3)3 and sufficient HCl continuously to make them react fully. After the reaction ends, the reaction product is centrifuged, washed, and dried to obtain LaCl3; Step S2: The Sn58Bi eutectic alloy, LaCl3, and flux are ball-milled and mixed under argon protection, and then melted in a melting furnace at a temperature of 170 °C for 15 min to obtain a composite soldering material.

[0044] Performance test

[0045] The low-temperature resistance performance of the soldering material of the present invention is tested. The samples are placed in different low-temperature environments and kept warm for a certain period of time. Then the samples are taken out from the low-temperature test chamber, and it is checked whether cracks, deformations, de-soldering, etc. occur in the welded parts of the sample appearance. The test results are as follows:

[0046]

[0047] The test results of the low-temperature resistance performance of the samples show that the antioxidant and low-temperature resistant soldering material of the present invention has excellent low-temperature resistance performance, can be used normally in extremely low-temperature environments, and has good application prospects.

[0048] As described above, only the specific embodiments of the present invention are provided, and the scope of the invention implementation cannot be limited by them. Therefore, the replacement of equivalent components, or equivalent changes and modifications made according to the scope of the present invention patent protection, should still fall within the scope covered by this patent. In addition, the technical features in the present invention can be freely combined and used among technical features, between technical features and technical inventions, and between technical inventions.

Claims

1. An antioxidant and low-temperature resistant soldering material, characterized in that, The solder material comprises: 87-95 wt% of SnBi-based eutectic alloy, 0.1-10 wt% of rare-earth modified MXene, and 1-7 wt% of soldering flux; the preparation process of the solder material is completed according to the following steps: Step S1: Prepare MXene by chemical etching method; Step S2: In-situ synthesize XCl3@MXene, where X is one of Ce and La, and the specific process of in-situ synthesizing XCl3@MXene is: Disperse the prepared MXene in deionized water to form a uniform suspension, add X2(CO3)3 and sufficient HCl to the MXene suspension and continuously stir to make it react fully, and after the reaction is completed, the reaction product is centrifuged, washed, and dried to obtain XCl3@MXene; the weight fraction ratio of MXene to X2(CO3)3 is 2:1-10; Step S3: Prepare XCl3@MXene-reinforced solder material by melting method or ball milling method.

2. An antioxidant and low-temperature resistant solder material according to claim 1, characterized in that, The SnBi-based eutectic alloy is one of Sn58Bi, Sn58Bi0.5Ag, Sn58Bi4Cu, Sn58Bi0.5In, and Sn58Bi3Zn, the rare earth is one of La and Ce, the soldering flux includes: 94-98 wt% of rosin, 1-3 wt% of active agent, and 0.5-3 wt% of surfactant, the active agent is at least one of succinic acid, adipic acid, sebacic acid, lauric acid, or triethanolamine, and the surfactant is at least one of pentaerythritol oleate or polyethylene glycol 200.

3. A preparation method of an antioxidant and low-temperature resistant solder material, characterized in that, The preparation process of the solder material is completed according to the following steps: Step S1: Prepare MXene by chemical etching method; Step S2: In-situ synthesize XCl3@MXene, where X is one of Ce and La, and the specific process of in-situ synthesizing XCl3@MXene is: Disperse the prepared MXene in deionized water to form a uniform suspension, add X2(CO3)3 and sufficient HCl to the MXene suspension and continuously stir to make it react fully, and after the reaction is completed, the reaction product is centrifuged, washed, and dried to obtain XCl3@MXene; the weight fraction ratio of MXene to X2(CO3)3 is 2:1-10; Step S3: Prepare XCl3@MXene-reinforced solder material by melting method or ball milling method.

4. The preparation method of an antioxidant and low-temperature resistant solder material according to claim 3, characterized in that, The specific process of preparing MXene by chemical etching method in Step S1 is: Add MAX phase powder into 40 wt% HF solution, then transfer it to a water bath at 40 °C and heat for 24 h. After the reaction is completed, the precipitate is centrifuged and washed with deionized water until the pH value is neutral, and finally dried in a vacuum drying oven at 60 °C for 24 h to obtain MXene powder.

5. The preparation method of an antioxidant and low-temperature resistant solder material according to claim 3, characterized in that The specific process of preparing XCl3@MXene-reinforced solder material by melting method in Step S3 is: Ball-mill and mix the SnBi-based eutectic alloy, rare-earth modified MXene, and soldering flux under argon protection, and then melt in a melting furnace at a temperature of 150-250 °C for 15-30 min to obtain a composite solder material.

6. The preparation method of an antioxidant and low-temperature resistant soldering material according to claim 3, characterized in that, The specific process of preparing the XCl3@MXene reinforced solder material by ball milling in step S3 is as follows: Add the SnBi-based eutectic alloy, rare earth modified MXene, and flux into a ball mill in a certain proportion, fill the ball mill with argon gas, and grind at a rotation speed of 2000 - 4000 r / min until the particle size of the solid particles ≤ 40 μm, then the composite solder material can be obtained.

Images