Preparation method of fine-grained high-strength tin powder

Abstract

The invention relates to the technical field of metal powder. The invention discloses a preparation method of fine-grained high-strength tin powder. The preparation method of the fine-grained high-strength tin powder comprises the following steps: S1, heating a tin raw material to 300-320 DEG C, and melting to obtain liquid tin; s2, the liquid tin is atomized and sprayed into a cooling medium through a nozzle, and refined tin powder is prepared; wherein the diameter of the nozzle ranges from 0.1 mm to 0.5 mm, and the pressure of the nozzle ranges from 5 MPa to 10 MPa; in the atomization process, mercaptobenzothiazole accounting for 0.01-0.1% of the weight of the liquid tin is added; s3, the refined tin powder is collected; s4, the refined tin powder is subjected to ball milling treatment; and S5, the refined tin powder obtained after ball milling treatment is subjected to annealing treatment, washing and drying, and the fine-grained high-strength tin powder is obtained. The prepared fine-grained high-strength tin powder is high in mechanical strength and good in toughness, and oxidation is effectively prevented.

Description

Technical Field

[0001] The present application relates to the technical field of metal powders, and in particular to a method for preparing fine-grained high-strength tin powder. Background Art

[0002] Tin powder is a fine particle made of metallic tin, which has a wide range of applications in electronics, metallurgy, chemical industry and other industries. Its low melting point (about 232°C), good electrical and thermal conductivity make tin powder an indispensable key material in the fields of electronic welding, metal surface treatment and special alloy manufacturing.

[0003] The tin powder commonly found on the market has achieved remarkable achievements in many fields, but it still has some inherent defects, which may affect its performance, processability and reliability of the final product, and also limit its wider application and development to a certain extent. For example, the mechanical strength of tin powder is relatively low, especially under high temperature conditions, it is prone to creep deformation, which limits its application under certain high strength requirements. Some tin powders may become brittle in low temperature environments, affecting their service life. In addition, tin powder is more susceptible to oxidation, especially in humid air.

[0004] Therefore, there is an urgent need to develop a fine-grained, high-strength tin powder with high mechanical strength, good toughness and effective oxidation resistance. Summary of the invention

[0005] In order to solve at least one of the above technical problems, a fine-grained high-strength tin powder with high mechanical strength, good toughness and effective oxidation resistance is developed. The present application provides a method for preparing fine-grained high-strength tin powder.

[0006] On the one hand, the present application provides a method for preparing fine-grained high-strength tin powder, comprising the following steps: S1, heating the tin raw material to 300-320°C, melting it, and obtaining liquid tin; S2, atomizing the liquid tin and spraying it into a cooling medium through a nozzle to obtain refined tin powder; wherein the nozzle diameter is 0.1-0.5 mm, and the nozzle pressure is 5-10 MPa; during the atomization process, adding 0.01-0.1% of mercaptobenzothiazole by weight of the liquid tin; S3, collecting the refined tin powder; S4, ball milling the refined tin powder; S5, annealing, washing and drying the refined tin powder after ball milling to obtain fine-grained high-strength tin powder.

[0007] By adopting the above technical scheme, the tin powder prepared by the preparation method of the present application has high mechanical strength, good toughness, and can effectively prevent oxidation. The ball milling process in step S4 of the present application is a mechanical activation process, which can refine the powder particles, increase the specific surface area of ​​the powder, improve the activity of the powder, and facilitate subsequent annealing. The refined powder is more likely to form a uniform microstructure, thereby improving the mechanical properties of the final product. In addition, the ball milling process in step S4 of the present application ensures that the powder has a uniform particle size, removes larger particles, and makes the final product have better consistency and applicability.

[0008] The melting step of step S1 of the present application ensures that the tin raw material is completely transformed into a liquid state, so as to facilitate the subsequent atomization process, and the tin in the liquid state is more easily dispersed into fine particles. The atomization of step S2 of the present application can prepare fine-grained tin powder. The addition of mercaptobenzothiazole in this process helps prevent the powder particles from aggregating during the cooling process and forms a protective film on the surface to reduce oxidation.

[0009] The annealing treatment in step S5 of the present application can eliminate the internal stress in the powder, improve the microstructure, and help improve the mechanical properties of the powder; washing can remove impurities and residues on the surface; and drying is to remove moisture and prevent the powder from agglomerating. Washing and drying ensure the purity and dryness of the powder, thereby improving its performance. The annealing temperature range of the present application can ensure that the tin powder fully releases the internal stress and optimizes its microstructure without melting. This temperature range is sufficient to activate the movement of atoms and promote the rearrangement of the lattice, but not too high to cause the powder to melt or deform.

[0010] The present application significantly improves the mechanical strength of tin powder by refining powder, optimizing microstructure and surface treatment. The uniform microstructure and proper annealing treatment improve the toughness of tin powder. The addition of mercaptobenzothiazole can form a protective layer on the powder surface, reduce oxidation, and thus extend the service life. The preparation method of the present application comprehensively improves the various performance indicators of tin powder, thereby preparing fine-grained high-strength tin powder with high mechanical strength, good toughness, and effective oxidation prevention.

[0011] Optionally, in step S4, the ball milling speed is 150-200 r / min, and the ball milling time is 24-48 h.

[0012] By adopting the above technical solution, the ball milling speed of the present application can increase the collision frequency and energy in the ball mill, which helps to refine the tin powder more quickly. High-speed rotation can also increase the interaction between the powder and the grinding medium, thereby making the powder more active, which is beneficial to the subsequent annealing process. The ball milling time of the present application can ensure that the powder is fully refined to reach the required particle size range, and also helps to evenly distribute the powder in the ball mill to avoid local uneven grinding.

[0013] Optionally, in step S2, the nozzle diameter is 0.2-0.4 mm.

[0014] By adopting the above technical solution, the nozzle diameter of the present application helps to ensure uniform distribution of droplets, thereby obtaining powder with relatively consistent particle size distribution, balancing particle size, production efficiency and powder quality, and can not only obtain fine-grained powder that meets the requirements, but also avoid clogging problems caused by nozzles that are too small.

[0015] Optionally, in step S2, the nozzle pressure is 7-8 MPa.

[0016] By adopting the above technical solution, the nozzle pressure of the present application can provide a stronger impact force, making it easier to break the liquid tin into finer particles, and also helps to form uniform droplets, thereby obtaining a powder with a more uniform particle size distribution.

[0017] Optionally, in step S2, the cooling medium is water.

[0018] By adopting the above technical solution, the present application adopts water as a cooling medium. Water has a high heat capacity and thermal conductivity, and can quickly take away the heat generated during the atomization of liquid tin, accelerating the solidification speed of the droplets. In addition, water is low-cost, green and environmentally friendly, and reduces the risk of fire and explosion. When the liquid tin is atomized into fine droplets and sprayed into the water through a nozzle, the water immediately begins to absorb the heat of the droplets, causing the droplets to cool rapidly and solidify into solid particles.

[0019] Optionally, in step S2, the amount of mercaptobenzothiazole added is 0.03-0.07% of the weight of the liquid tin.

[0020] By adopting the above technical solution, the present application adds mercaptobenzothiazole, which can form a protective film on the surface of the tin powder to prevent the tin powder from oxidizing during cooling and subsequent storage. Mercaptobenzothiazole also has a surface active effect, which can improve the dispersibility and fluidity of liquid tin during atomization, help form more uniform particles, and prevent powder particles from aggregating during cooling, thereby improving the fluidity and processing performance of the powder.

[0021] Optionally, in step S5, the annealing temperature is 200-300°C.

[0022] Optionally, in step S5, the annealing time is 2 to 4 hours.

[0023] By adopting the above technical scheme, the present application further improves the microstructure and performance of tin powder through annealing treatment to improve its mechanical strength and toughness and reduce internal stress. Annealing can eliminate the internal stress introduced by rapid cooling during the preparation process. Appropriate annealing temperature and time can effectively release these stresses and improve the stability and durability of the powder. The annealing time of the present application can ensure that the annealing process is fully carried out, so that the internal stress is released and the microstructure is optimized. Too short a time may not completely eliminate the stress, while too long a time may increase energy consumption.

[0024] Optionally, in step S5, the drying is vacuum drying or oven drying.

[0025] By adopting the above technical solution, the vacuum drying of the present application can better prevent oxidation and complete the drying process at a lower temperature. Oven drying has lower cost, is easy to operate, and is suitable for large-scale production.

[0026] In a second aspect, the fine-grained high-strength tin powder of the present application is prepared by the above-mentioned method for preparing fine-grained high-strength tin powder.

[0027] By adopting the above technical solution, the fine-grained high-strength tin powder prepared in the present application has fine and uniform particle size, high strength, good toughness and excellent anti-oxidation performance. These characteristics make the tin powder have a wide range of application prospects in the fields of electronic welding, metal surface treatment and special alloy manufacturing.

[0028] In summary, the present invention includes at least one of the following beneficial technical effects: 1. The preparation method of the present application significantly improves the mechanical strength of the tin powder, and appropriate annealing treatment improves the toughness of the tin powder. The addition of mercaptobenzothiazole can form a protective layer on the powder surface to reduce oxidation.

[0029] 2. The atomization of the present application 3 can prepare fine-grained tin powder. In this process, the addition of mercaptobenzothiazole can form a protective film on its surface to reduce oxidation.

[0030] 3. The fine-grained high-strength tin powder prepared in the present application has fine and uniform particle size, high strength, good toughness and excellent anti-oxidation properties. DETAILED DESCRIPTION

[0031] The present application is further described in detail below in conjunction with embodiments.

[0032] The present application proposes a method for preparing fine-grained high-strength tin powder, comprising the following steps: S1, heating the tin raw material to 300-320°C, melting it, and obtaining liquid tin; S2, atomizing the liquid tin and spraying it into a cooling medium through a nozzle to obtain refined tin powder; wherein the nozzle diameter is 0.1-0.5 mm, and the nozzle pressure is 5-10 MPa; during the atomization process, adding 0.01-0.1% of mercaptobenzothiazole by weight of the liquid tin; S3, collecting the refined tin powder; S4, ball milling the refined tin powder; S5, annealing, washing and drying the refined tin powder after ball milling to obtain fine-grained high-strength tin powder.

[0033] The fine-grained high-strength tin powder of the present application is prepared by the above-mentioned method for preparing fine-grained high-strength tin powder.

[0034] The present application significantly improves the mechanical strength of tin powder by refining powder, optimizing microstructure and surface treatment. The uniform microstructure and proper annealing treatment improve the toughness of tin powder. The addition of mercaptobenzothiazole can form a protective layer on the powder surface, reduce oxidation, and thus extend the service life. The preparation method of the present application comprehensively improves the various performance indicators of tin powder, thereby preparing fine-grained high-strength tin powder with high mechanical strength, good toughness, and effective oxidation prevention.

[0035] The raw materials used in this application are all from commercially available products, as follows: Mercaptobenzothiazole: CAS: 149-30-4. Specific embodiments

[0036] Examples 1 to 3 Example 1 This embodiment provides a method for preparing fine-grained high-strength tin powder, comprising the following steps: S1, heating the tin ingot to 300°C, melting it, and obtaining liquid tin; S2, atomizing the liquid tin and spraying it into a cooling medium through a nozzle, wherein the cooling medium is water, to obtain refined tin powder; wherein the nozzle diameter is 0.1 mm and the nozzle pressure is 10 MPa; during the atomization process, adding 0.01% mercaptobenzothiazole by weight of the liquid tin; S3, collecting the refined tin powder using a dust collecting device; S4, ball milling the refined tin powder, the ball milling speed is 175r / min, and the ball milling time is 36h; S5. The ball-milled powder is annealed at a temperature of 200° C. for 3 h, washed, and vacuum-dried to obtain fine-grained high-strength tin powder.

[0037] Example 2 This embodiment provides a method for preparing fine-grained high-strength tin powder, comprising the following steps: S1, heating the tin ingot to 310°C, melting it, and obtaining liquid tin; S2, atomizing the liquid tin and spraying it into a cooling medium through a nozzle, wherein the cooling medium is water, to obtain refined tin powder; wherein the nozzle diameter is 0.3 mm and the nozzle pressure is 7.5 MPa; during the atomization process, adding 0.05% of mercaptobenzothiazole by weight of the liquid tin; S3, collecting the refined tin powder using a dust collecting device; S4, ball milling the refined tin powder, the ball milling speed is 175r / min, and the ball milling time is 36h; S5. The ball-milled powder is annealed at a temperature of 250° C. for 3 h, washed, and vacuum-dried to obtain fine-grained high-strength tin powder.

[0038] Example 3 This embodiment provides a method for preparing fine-grained high-strength tin powder, comprising the following steps: S1, heating the tin ingot to 320°C, melting it, and obtaining liquid tin; S2, atomizing the liquid tin and spraying it into a cooling medium through a nozzle, wherein the cooling medium is water, to obtain refined tin powder; wherein the nozzle diameter is 0.5 mm and the nozzle pressure is 5 MPa; during the atomization process, adding 0.1% mercaptobenzothiazole by weight of the liquid tin; S3, collecting the refined tin powder using a dust collecting device; S4, ball milling the tin powder, the ball milling speed is 175r / min, and the ball milling time is 36h; S5. The ball-milled powder is annealed at a temperature of 300° C. for 3 h, washed, and vacuum-dried to obtain fine-grained high-strength tin powder.

[0039] Comparative Examples 1 to 3 Comparative Example 1 The difference between Comparative Example 1 and Example 2 is that Comparative Example 1 does not contain the ball milling treatment in step S4, and the specific preparation method is: S1, heating the tin ingot to 310°C, melting it, and obtaining liquid tin; S2, atomizing the liquid tin and spraying it into a cooling medium through a nozzle, wherein the cooling medium is water, to obtain refined tin powder; wherein the nozzle diameter is 0.3 mm and the nozzle pressure is 7.5 MPa; during the atomization process, adding 0.05% of mercaptobenzothiazole by weight of the liquid tin; S3, collecting the refined tin powder using a dust collecting device; S4, annealing the refined tin powder at a temperature of 250° C. for 3 h, washing, and vacuum drying to obtain fine-grained high-strength tin powder.

[0040] Comparative Example 2 The difference between Comparative Example 2 and Example 2 is that mercaptobenzothiazole is not added in Comparative Example 2, and the specific preparation method is: S1, heating the tin ingot to 310°C, melting it, and obtaining liquid tin; S2, atomizing the liquid tin and spraying it into a cooling medium through a nozzle, wherein the cooling medium is water, to obtain refined tin powder; wherein the nozzle diameter is 0.3 mm and the nozzle pressure is 7.5 MPa; S3, collecting the refined tin powder using a dust collecting device; S4, ball milling the refined tin powder, the ball milling speed is 175r / min, and the ball milling time is 36h; S5. The ball-milled powder is annealed at a temperature of 250° C. for 3 h, washed, and vacuum-dried to obtain fine-grained high-strength tin powder.

[0041] Comparative Example 3 The difference between Comparative Example 3 and Example 2 is that Comparative Example 3 does not undergo annealing treatment, and the specific preparation method is as follows: S1, heating the tin ingot to 310°C, melting it, and obtaining liquid tin; S2, atomizing the liquid tin and spraying it into a cooling medium through a nozzle, wherein the cooling medium is water, to obtain refined tin powder; wherein the nozzle diameter is 0.3 mm and the nozzle pressure is 7.5 MPa; during the atomization process, adding 0.05% of mercaptobenzothiazole by weight of the liquid tin; S3, collecting the refined tin powder using a dust collecting device; S4, ball milling the refined tin powder, the ball milling speed is 175r / min, and the ball milling time is 36h; S5. Wash the ball-milled powder, and vacuum dry it to obtain fine-grained high-strength tin powder.

[0042] Experimental testing Test items and test methods Mechanical strength: The tensile strength of fine-grained high-strength tin powder is tested according to ASTM E8 / E8M; Toughness: The impact toughness of fine-grained high-strength tin powder is tested according to ASTM E23 "Charpy V-notch impact test method for metallic materials"; Anti-oxidation performance: Place fine-grained high-strength tin powder at 85°C and 85% humidity for 168 hours, and observe the color and glossiness of the tin powder. If gray, brown or green spots or layers appear on the surface of the tin powder and the surface is dull, it is judged to be oxidized and deteriorated, and the oxidation deterioration rate is tested.

[0043] The tensile strength, impact toughness and oxidation deterioration rate of the fine-grained high-strength tin powders prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were tested. The test results are shown in Table 1.

[0044] Table 1 From the test results in Table 1, it can be seen that the fine-grained high-strength tin powder prepared in Examples 1 to 3 has high tensile strength and impact toughness, low oxidation deterioration rate, high mechanical strength, good toughness, and can effectively prevent oxidation.

[0045] Comparative Example 1 does not include the ball milling treatment in step S4, and the mechanical strength and toughness of the prepared fine-grained high-strength tin powder are reduced.

[0046] In Comparative Example 2, mercaptobenzothiazole was not added, and the oxidation deterioration rate of the prepared fine-grained high-strength tin powder was significantly increased.

[0047] In Comparative Example 3, no annealing treatment was performed, and the mechanical strength and toughness of the prepared fine-grained high-strength tin powder were significantly reduced.

[0048] Embodiments 4 to 13 Example 4 The difference between Example 4 and Example 2 is that the ball milling speed of Example 4 is 150 r / min and the ball milling time is 48 h.

[0049] Example 5 The difference between Example 5 and Example 2 is that the ball milling speed of Example 5 is 200 r / min and the ball milling time is 24 h.

[0050] Example 6 The difference between Example 6 and Example 2 is that the nozzle diameter of Example 6 is 0.2 mm.

[0051] Example 7 The difference between Example 7 and Example 2 is that the nozzle diameter of Example 7 is 0.4 mm.

[0052] Example 8 The difference between Example 8 and Example 2 is that the nozzle pressure of Example 8 is 7 MPa.

[0053] Example 9 The difference between Example 9 and Example 2 is that the nozzle pressure of Example 9 is 8 MPa.

[0054] Example 10 The difference between Example 10 and Example 2 is that in step S2 of Example 10, the amount of mercaptobenzothiazole added is 0.03% of the weight of the liquid tin.

[0055] Embodiment 11 The difference between Example 11 and Example 2 is that in step S2 of Example 11, the amount of mercaptobenzothiazole added is 0.07% of the weight of the liquid tin.

[0056] Example 12 The difference between Example 12 and Example 2 is that in step S5 of Example 12, the annealing time is 2 hours.

[0057] Embodiment 13 The difference between Example 13 and Example 2 is that in step S5 of Example 13, the annealing time is 4 hours.

[0058] The fine-grained high-strength tin powders prepared in Examples 4 to 13 were tested for tensile strength, impact toughness and oxidation deterioration rate. The test results are shown in Table 2.

[0059] Table 2 From the test results in Table 2, it can be seen that the difference between Example 4 and Example 5 and Example 2 is that the ball milling speed and ball milling time in step S1 are different. Among them, the fine-grained high-strength tin powder prepared in Example 2 has the best mechanical strength and toughness.

[0060] The difference between Example 6 and Example 7 and Example 2 is that the nozzle diameters are different, and the fine-grained high-strength tin powder prepared in Example 2 has the best mechanical strength and toughness.

[0061] The difference between Example 8 and Example 9 and Example 2 is that the nozzle pressure is different. Among them, the fine-grained high-strength tin powder prepared in Example 2 has the best mechanical strength and toughness.

[0062] The difference between Example 10 and Example 11 and Example 2 is that the added amounts of mercaptobenzothiazole are different. Among them, the fine-grained high-strength tin powder prepared in Example 2 has the best antioxidant performance.

[0063] The difference between Example 12 and Example 13 and Example 2 is that the annealing time of step S5 is different, wherein the fine-grained high-strength tin powder prepared in Example 2 has the best mechanical strength and toughness.

[0064] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for preparing fine-grained high-strength tin powder, characterized in that: The following steps are involved: S1, heating the tin raw material to 300-320°C, melting it, and obtaining liquid tin; S2, atomizing the liquid tin and spraying it into a cooling medium through a nozzle to obtain refined tin powder; wherein the nozzle diameter is 0.1-0.5 mm, and the nozzle pressure is 5-10 MPa; during the atomization process, adding 0.01-0.1% of mercaptobenzothiazole by weight of the liquid tin; S3, collecting the refined tin powder; S4, ball milling the refined tin powder; S5, annealing, washing and drying the refined tin powder after ball milling to obtain fine-grained high-strength tin powder.

2. The method for preparing fine-grained high-strength tin powder according to claim 1, characterized in that: In step S4, the ball milling speed is 150-200 r / min, and the ball milling time is 24-48 h.

3. The method for preparing fine-grained high-strength tin powder according to claim 1, characterized in that: In step S2, the nozzle diameter is 0.2-0.4 mm.

4. The method for preparing fine-grained high-strength tin powder according to claim 1, characterized in that: In step S2, the nozzle pressure is 7-8 MPa.

5. The method for preparing fine-grained high-strength tin powder according to claim 1, characterized in that: In step S2, the cooling medium is water.

6. The method for preparing fine-grained high-strength tin powder according to claim 1, characterized in that: In the step S2, the amount of mercaptobenzothiazole added is 0.03-0.07% of the weight of the liquid tin.

7. The method for preparing fine-grained high-strength tin powder according to claim 1, characterized in that: In step S5, the annealing temperature is 200-300°C.

8. The method for preparing fine-grained high-strength tin powder according to claim 1, characterized in that: In step S5, the annealing time is 2 to 4 hours.

9. The method for preparing fine-grained high-strength tin powder according to claim 1, characterized in that: In step S5, the drying is vacuum drying or oven drying.

10. A fine-grained high-strength tin powder, characterized in that: The tin powder is prepared by the method for preparing fine-grained high-strength tin powder according to any one of claims 1 to 9.

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