Preparation method of fine-grained high-strength tin powder

Abstract

The application relates to the technical field of metal powder, and discloses a preparation method of fine-granularity high-strength tin powder. The preparation method of the fine-granularity high-strength tin powder comprises the following steps: S1, tin raw materials are heated to 300-320 DEG C and melted to prepare liquid tin; S2, the liquid tin is atomized and sprayed into a cooling medium through a nozzle to prepare refined tin powder; wherein the diameter of the nozzle is 0.1-0.5 mm, and the pressure of the nozzle is 5-10 MPa; during the atomization process, 0.01-0.1% of mercaptobenzothiazole by 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 after the ball milling treatment is subjected to annealing treatment, washing and drying to prepare the fine-granularity high-strength tin powder. The fine-granularity high-strength tin powder prepared by the application has high mechanical strength, good toughness and can effectively prevent oxidation.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of metal powder, in particular to a preparation method of fine-granularity high-strength tin powder. BACKGROUND

[0002] Tin powder is a fine particle made of metal tin and has a wide application prospect in many industries such as electronics, metallurgy and chemical industry. Its low melting point (about 232 DEG C), good electrical conductivity 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 common tin powder on the market has achieved remarkable achievements in many fields, but still has some inherent defects, which may affect its performance, processability and reliability of the final product, and also limits its wider application and development to some extent. For example, the mechanical strength of tin powder is relatively low, and especially prone to creep deformation under high temperature conditions, which limits its application under certain high strength requirements. And some tin powder may become brittle in low temperature environment, affecting its service life. Moreover, tin powder is easy to oxidize, especially in humid air.

[0004] Therefore, it is urgent to develop a fine-granularity high-strength tin powder with high mechanical strength, good toughness and effective oxidation prevention. SUMMARY

[0005] In order to solve at least one of the above technical problems, a fine-granularity high-strength tin powder with high mechanical strength, good toughness and effective oxidation prevention is developed, and a preparation method of fine-granularity high-strength tin powder is provided.

[0006] In one aspect, the application provides a preparation method of fine-granularity high-strength tin powder, which comprises the following steps:

[0007] S1, heating tin raw material to 300-320 DEG C to melt and prepare liquid tin;

[0008] S2, atomizing the liquid tin and spraying it into a cooling medium through a nozzle to prepare refined tin powder; wherein the diameter of the nozzle is 0.1-0.5 mm, and the nozzle pressure is 5-10 MPa; during the atomization process, 0.01-0.1% of mercaptobenzothiazole by weight of the liquid tin is added;

[0009] S3, collecting the refined tin powder;

[0010] S4, ball milling the refined tin powder;

[0011] S5, annealing, washing and drying the ball-milled refined tin powder to prepare fine-granularity high-strength tin powder.

[0012] By adopting the above technical solution, 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 that 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.

[0013] The melting step in step S1 of the present application ensures that the tin raw material is completely converted into a liquid state, facilitating the subsequent atomization process. Furthermore, the tin in the liquid state is more easily dispersed into fine particles. The atomization in step S2 of the present application can produce fine-grained tin powder. The addition of mercaptobenzothiazole during this process helps prevent the powder particles from agglomerating during cooling and forms a protective film on their surface, reducing oxidation.

[0014] 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 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.

[0015] This application significantly improves the mechanical strength of tin powder through powder refinement, microstructure optimization, and surface treatment. A uniform microstructure and appropriate annealing treatment enhance its toughness. The addition of mercaptobenzothiazole forms a protective layer on the powder surface, reducing oxidation and thus extending its service life. This preparation method comprehensively enhances various performance indicators of tin powder, resulting in a fine-grained, high-strength tin powder with high mechanical strength, excellent toughness, and effective oxidation resistance.

[0016] Optionally, in step S4, the ball milling speed is 150-200 r / min, and the ball milling time is 24-48 h.

[0017] By adopting the above technical solution, the ball milling speed of this application can increase the collision frequency and energy within the ball mill, helping 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 and facilitating the subsequent annealing process. The ball milling time of this application can ensure that the powder is fully refined to the desired particle size range, and also helps to evenly distribute the powder within the ball mill, avoiding localized uneven grinding.

[0018] Optionally, in the step S2, the nozzle diameter is 0.2-0.4mm.

[0019] By adopting the above technical solution, the nozzle diameter of the present application helps to ensure the uniform distribution of liquid droplets, so as to obtain powder with relatively consistent particle size distribution, balancing the particle size, production efficiency and powder quality, which can obtain fine powder meeting the requirements, and avoid the problem of blockage caused by too small nozzle.

[0020] Optionally, in the step S2, the nozzle pressure is 7-8MPa.

[0021] By adopting the above technical solution, the nozzle pressure of the present application can provide stronger impact force, so that the liquid tin is more easily broken into smaller particles. It is also helpful to form uniform liquid droplets, so as to obtain powder with relatively consistent particle size distribution.

[0022] Optionally, in the step S2, the cooling medium is water.

[0023] By adopting the above technical solution, the present application uses water as the cooling medium. Water has high heat capacity and thermal conductivity, which can quickly take away the heat generated in the atomization process of liquid tin, and accelerate the solidification speed of liquid droplets. Moreover, water is low in cost, green and environmentally friendly, and also reduces the risk of fire and explosion. When the liquid tin is atomized into small liquid droplets and sprayed into water through the nozzle, the water immediately starts to absorb the heat of the liquid droplets, causing the liquid droplets to cool rapidly and solidify into solid particles.

[0024] Optionally, in the step S2, the addition amount of mercaptobenzothiazole is 0.03-0.07% of the weight of the liquid tin.

[0025] By adopting the above technical solution, the present application adds mercaptobenzothiazole, which can form a protective film on the surface of the tin powder, preventing the tin powder from oxidizing during cooling and subsequent storage. Mercaptobenzothiazole also has a surface activity effect, which can improve the dispersibility and flowability of liquid tin during atomization, helping to form more uniform particles, and preventing powder particles from aggregating during cooling, thereby improving the flowability and processing performance of the powder.

[0026] Optionally, in the step S5, the annealing temperature is 200-300℃.

[0027] Optionally, in the step S5, the annealing time is 2-4h.

[0028] By adopting the technical scheme, the microstructure and performance of the tin powder are further improved by annealing treatment to improve the mechanical strength and toughness of the tin powder and reduce internal stress. Annealing can eliminate internal stress introduced due to rapid cooling in the preparation process. Proper annealing temperature and time can effectively release the stress 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 time may not completely eliminate the stress, and too long time may increase energy consumption.

[0029] Optionally, in the step S5, the drying is vacuum drying or oven drying.

[0030] By adopting the technical scheme, the vacuum drying of the present application can better prevent oxidation and can complete the drying process at a lower temperature. The oven drying is low in cost and simple in operation, and is suitable for large-scale production.

[0031] In a second aspect, the fine-grained high-strength tin powder is prepared by the above-mentioned method for preparing a fine-grained high-strength tin powder.

[0032] By adopting the technical scheme, the fine-grained high-strength tin powder prepared by the present application has fine and uniform particle size, high strength, good toughness, and excellent oxidation resistance. These characteristics make the tin powder have wide application prospects in the fields of electronic welding, metal surface treatment, and special alloy manufacturing.

[0033] In summary, the present application includes at least one of the following beneficial technical effects:

[0034] 1. The preparation method of the present application significantly improves the mechanical strength of the tin powder, the proper annealing treatment improves the toughness of the tin powder, and the addition of mercaptobenzothiazole can form a protective layer on the surface of the powder to reduce oxidation.

[0035] 2. The atomization of the present application 3 can prepare fine-grained tin powder, and the addition of mercaptobenzothiazole in the process can form a protective film on the surface of the tin powder to reduce oxidation.

[0036] 3. The fine-grained high-strength tin powder prepared by the present application has fine and uniform particle size, high strength, good toughness, and excellent oxidation resistance. DETAILED DESCRIPTION

[0037] The present application will be further described in detail below in combination with examples.

[0038] The present application designs a preparation method of fine-grained high-strength tin powder, including the following steps:

[0039] S1, heat the tin raw material to 300-320℃, melt to obtain liquid tin; S2, spray the liquid tin into a cooling medium to obtain a tin powder;

[0040] S2, atomizing the liquid tin and spraying the atomized tin into a cooling medium through a nozzle to obtain the refined tin powder; wherein the diameter of the nozzle is 0.1-0.5mm, the pressure of the nozzle is 5-10MPa, and 0.01-0.1% of mercaptobenzothiazole by weight of the liquid tin is added during the atomization;

[0041] S3, collecting the refined tin powder;

[0042] S4, ball-milling the refined tin powder;

[0043] S5, annealing, washing and drying the ball-milled refined tin powder to obtain the fine-grained high-strength tin powder.

[0044] The fine-grained high-strength tin powder of the present application is prepared by the above method.

[0045] The present application significantly improves the mechanical strength of the tin powder by refining the powder, optimizing the microstructure and surface treatment, and the toughness of the tin powder by uniform microstructure and appropriate annealing treatment, and the service life is prolonged by the addition of mercaptobenzothiazole to form a protective layer on the surface of the powder and reduce oxidation. The preparation method of the present application comprehensively improves various performance indicators of the tin powder, thereby preparing a fine-grained high-strength tin powder with high mechanical strength, good toughness and effective oxidation prevention.

[0046] The raw materials used in the present application are all from commercially available products, and are as follows:

[0047] Mercaptobenzothiazole: CAS: 149-30-4. Specific embodiments

[0049] Examples 1-3

[0050] Example 1

[0051] The present embodiment provides a preparation method of a fine-grained high-strength tin powder, comprising the following steps:

[0052] S1, heating a tin ingot to 300℃ to obtain liquid tin;

[0053] S2, atomizing the liquid tin and spraying the atomized tin into a cooling medium through a nozzle to obtain the refined tin powder; wherein the diameter of the nozzle is 0.1mm, the pressure of the nozzle is 10MPa, and 0.01% of mercaptobenzothiazole by weight of the liquid tin is added during the atomization;

[0054] S3, collecting the refined tin powder using a dust collection device;

[0055] S4, the refined tin powder is subjected to ball milling treatment, the ball milling speed is 175 r / min, and the ball milling time is 36 h;

[0056] S5, the powder after the ball milling is subjected to annealing treatment, the annealing temperature is 200 DEG C, the annealing time is 3 h, and then the powder is washed and vacuum dried to obtain the fine-grained high-strength tin powder.

[0057] Example 2

[0058] The embodiment provides a preparation method of fine-grained high-strength tin powder, which comprises the following steps:

[0059] S1, the tin ingot is heated to 310 DEG C to be melted to obtain liquid tin;

[0060] S2, the liquid tin is atomized and sprayed into a cooling medium through a nozzle, the cooling medium is water, and refined tin powder is obtained; wherein the nozzle diameter is 0.3 mm, the nozzle pressure is 7.5 MPa; during the atomization process, 0.05% of mercaptobenzothiazole by weight of the liquid tin is added;

[0061] S3, the refined tin powder is collected by using a dust collection device;

[0062] S4, the refined tin powder is subjected to ball milling treatment, the ball milling speed is 175 r / min, and the ball milling time is 36 h;

[0063] S5, the powder after the ball milling is subjected to annealing treatment, the annealing temperature is 250 DEG C, the annealing time is 3 h, and then the powder is washed and vacuum dried to obtain the fine-grained high-strength tin powder.

[0064] Example 3

[0065] The embodiment provides a preparation method of fine-grained high-strength tin powder, which comprises the following steps:

[0066] S1, the tin ingot is heated to 320 DEG C to be melted to obtain liquid tin;

[0067] S2, the liquid tin is atomized and sprayed into a cooling medium through a nozzle, the cooling medium is water, and refined tin powder is obtained; wherein the nozzle diameter is 0.5 mm, the nozzle pressure is 5 MPa; during the atomization process, 0.1% of mercaptobenzothiazole by weight of the liquid tin is added;

[0068] S3, the refined tin powder is collected by using a dust collection device;

[0069] S4, the tin powder is subjected to ball milling treatment, the ball milling speed is 175 r / min, and the ball milling time is 36 h;

[0070] S5, the powder after the ball milling is subjected to annealing treatment, the annealing temperature is 300 DEG C, the annealing time is 3 h, and then the powder is washed and vacuum dried to obtain the fine-grained high-strength tin powder.

[0071] Comparative Example 1-3

[0072] Comparative Example 1

[0073] The difference between Comparative Example 1 and Example 2 is that Comparative Example 1 does not contain the ball milling treatment of step S4, and the specific preparation method is as follows:

[0074] S1, heating tin ingot to 310℃, melting to obtain liquid tin;

[0075] S2, atomizing the liquid tin and spraying it into a cooling medium through a nozzle, the cooling medium is water, to obtain refined tin powder; wherein the nozzle diameter is 0.3mm, and the nozzle pressure is 7.5MPa; during the atomization process, 0.05% of mercaptobenzothiazole by weight of the liquid tin is added;

[0076] S3, collecting the refined tin powder by using a dust collection device;

[0077] S4, annealing the refined tin powder at a temperature of 250℃ for 3h, washing, and vacuum drying to obtain fine-grained high-strength tin powder.

[0078] Comparative Example 2

[0079] The difference between Comparative Example 2 and Example 2 is that Comparative Example 2 does not add mercaptobenzothiazole, and the specific preparation method is as follows:

[0080] S1, heating tin ingot to 310℃, melting to obtain liquid tin;

[0081] S2, atomizing the liquid tin and spraying it into a cooling medium through a nozzle, the cooling medium is water, to obtain refined tin powder; wherein the nozzle diameter is 0.3mm, and the nozzle pressure is 7.5MPa;

[0082] S3, collecting the refined tin powder by using a dust collection device;

[0083] S4, ball milling the refined tin powder at a speed of 175r / min for 36h;

[0084] S5, annealing the ball-milled powder at a temperature of 250℃ for 3h, washing, and vacuum drying to obtain fine-grained high-strength tin powder.

[0085] Comparative Example 3

[0086] 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:

[0087] S1, heating tin ingot to 310℃, melting to obtain liquid tin;

[0088] S2, atomizing the liquid tin and spraying the atomized tin into a cooling medium through a nozzle, wherein the cooling medium is water, to obtain tin powder; wherein the diameter of the nozzle is 0.3 mm and the pressure of the nozzle is 7.5 MPa; and wherein 0.05% of mercaptobenzothiazole by weight of the liquid tin is added during the atomization process;

[0089] S3, collecting the tin powder by using a dust collection device;

[0090] S4, ball-milling the tin powder, wherein the rotation speed of the ball-milling is 175 r / min and the ball-milling time is 36 h;

[0091] S5, washing and vacuum drying the ball-milled tin powder to obtain the fine-grained high-strength tin powder.

[0092] Experimental detection

[0093] Detection items and detection methods

[0094] Mechanical strength: the tensile strength of the fine-grained high-strength tin powder is detected according to ASTM E8 / E8M;

[0095] Toughness: the impact toughness of the fine-grained high-strength tin powder is detected according to ASTM E23 “Metallic Materials Charpy V-Notch Impact Test Method”;

[0096] Anti-oxidation performance: the fine-grained high-strength tin powder is placed in a temperature of 85°C and a humidity of 85% for 168 h, and the color and gloss of the tin powder are observed. If gray, brown or green spots or layered substances appear on the surface of the tin powder, and the surface is dull and lacks luster, it is judged that the tin powder is oxidized and deteriorated, and the oxidation deterioration rate is detected.

[0097] The tensile strength, impact toughness and oxidation deterioration rate of the fine-grained high-strength tin powder prepared in Examples 1-3 and Comparative Examples 1-3 are detected, and the detection results are shown in Table 1.

[0098] Table 1

[0099]

[0100]

[0101] From the detection results in Table 1, it can be seen that the fine-grained high-strength tin powder prepared in Examples 1-3 has high tensile strength and impact toughness, low oxidation deterioration rate, high mechanical strength and good toughness, and can effectively prevent oxidation.

[0102] Comparative Example 1 does not contain the ball-milling process in step S4, and the mechanical strength and toughness of the fine-grained high-strength tin powder prepared are reduced.

[0103] Comparative Example 2 does not add mercaptobenzothiazole, and the oxidation deterioration rate of the fine-grained high-strength tin powder prepared is significantly increased.

[0104] Comparative Example 3 was not annealed, and the mechanical strength and toughness of the fine high-strength tin powder prepared was significantly reduced.

[0105] Examples 4 to 13

[0106] Example 4

[0107] Example 4 differs from Example 2 in that the ball milling speed of Example 4 was 150 r / min and the ball milling time was 48 h.

[0108] Example 5

[0109] Example 5 differs from Example 2 in that the ball milling speed of Example 5 was 200 r / min and the ball milling time was 24 h.

[0110] Example 6

[0111] Example 6 differs from Example 2 in that the nozzle diameter of Example 6 was 0.2 mm.

[0112] Example 7

[0113] Example 7 differs from Example 2 in that the nozzle diameter of Example 7 was 0.4 mm.

[0114] Example 8

[0115] Example 8 differs from Example 2 in that the nozzle pressure of Example 8 was 7 MPa.

[0116] Example 9

[0117] Example 9 differs from Example 2 in that the nozzle pressure of Example 9 was 8 MPa.

[0118] Example 10

[0119] Example 10 differs from Example 2 in that in Step S2 of Example 10, the amount of mercaptobenzothiazole added was 0.03% by weight of the liquid tin.

[0120] Example 11

[0121] Example 11 differs from Example 2 in that in Step S2 of Example 11, the amount of mercaptobenzothiazole added was 0.07% by weight of the liquid tin.

[0122] Example 12

[0123] Example 12 differs from Example 2 in that in Step S5 of Example 12, the annealing time was 2 h.

[0124] Example 13

[0125] Example 13 differs from Example 2 in that the annealing time in step S5 of Example 13 is 4h.

[0126] The fine-grained high-strength tin powder prepared in Examples 4-13 was subjected to tensile strength, impact toughness and oxidation deterioration rate tests, and the test results are shown in Table 2.

[0127] Table 2

[0128]

[0129] From the test results in Table 2, it can be seen that the difference between Example 4, Example 5 and Example 2 is that the ball milling speed and ball milling time in step S1 are different, and the mechanical strength and toughness of the fine-grained high-strength tin powder prepared in Example 2 are the best.

[0130] The difference between Example 6, Example 7 and Example 2 is that the nozzle diameter is different, and the mechanical strength and toughness of the fine-grained high-strength tin powder prepared in Example 2 are the best.

[0131] The difference between Example 8, Example 9 and Example 2 is that the nozzle pressure is different, and the mechanical strength and toughness of the fine-grained high-strength tin powder prepared in Example 2 are the best.

[0132] The difference between Example 10, Example 11 and Example 2 is that the amount of mercaptobenzothiazole added is different, and the anti-oxidation performance of the fine-grained high-strength tin powder prepared in Example 2 is the best.

[0133] The difference between Example 12, Example 13 and Example 2 is that the annealing time in step S5 is different, and the mechanical strength and toughness of the fine-grained high-strength tin powder prepared in Example 2 are the best.

[0134] The above are preferred embodiments of the present application, and do not limit the protection scope of the present application, so: any equivalent changes made in the structure, shape, principle of the present application should be covered within 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 to melt it and obtain 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 the refined tin powder after ball milling, washing, and drying to obtain fine-grained high-strength tin powder; In step S4, the ball milling speed is 150-200 r / min, and the ball milling time is 24-48 h; In step S5, the annealing temperature is 200-300° C., and the annealing time is 2-4 hours.

2. 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.

3. 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.

4. 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.

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

6. 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.

7. 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 6.

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