Powder metallurgy product with improved friction performance and preparation method thereof

Abstract

The invention provides a powder metallurgy product with improved friction performance and a preparation method thereof, and relates to the technical field of powder metallurgy. The powder metallurgy product for improving the friction performance comprises the following raw materials in parts by weight: 20-25 parts of copper powder, 3-7 parts of tin powder, 5-7 parts of aluminum powder, 3-7 parts of cuprous oxide, 12-13 parts of graphite and 13-15 parts of molybdenum disulfide. Diffusion bonding among powder particles is enhanced by applying pulse current in the pressure forming process, the density is improved, the strength distribution of metallurgical products is uniform, and Joule heating and diffusion bonding among the powder particles are promoted by applying pulse current in the sintering process and combining with mechanical pressure. Local high temperature (plasma discharge effect) is generated at a particle contact point, rapid sintering is promoted, the whole process can be completed within several minutes to dozens of minutes, the sintering temperature is reduced, the sintering time is greatly shortened, and the preparation efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of powder metallurgy, and specifically relates to a powder metallurgy product for improving friction performance and a preparation method thereof. Background Art

[0002] Powder metallurgy is a process technology that manufactures metal materials, composite materials, and various types of products by producing metal powders or using metal powders (or mixtures with non-metal powders) as raw materials, through shaping and sintering. In order to improve the friction performance of existing powder metallurgy products, graphite and molybdenum disulfide are added to the metal powder raw materials to improve the wear resistance of metal products.

[0003] However, graphite and molybdenum disulfide cannot be uniformly mixed with the metal powder raw materials during the mixing process, resulting in uneven surface strength distribution of the metallurgical products. In addition, there are problems such as too high temperature and too long sintering time during the sintering process. Summary of the Invention

[0004] (I) Technical Problems to be Solved

[0005] In view of the deficiencies of the prior art, the present invention provides a powder metallurgy product for improving friction performance and a preparation method thereof, which solve the problems of uneven surface strength distribution of existing powder metallurgy products, and too high temperature and too long sintering time during the sintering process.

[0006] (II) Technical Solutions

[0007] To achieve the above objectives, the present invention is realized through the following technical solutions: A powder metallurgy product for improving friction performance, comprising the following raw materials in parts by weight: 20 - 25 parts of copper powder, 3 - 7 parts of tin powder, 5 - 7 parts of aluminum powder, 3 - 7 parts of cuprous oxide, 12 - 13 parts of graphite, and 13 - 15 parts of molybdenum disulfide.

[0008] A preparation method of a powder metallurgy product for improving friction performance, comprising the following specific steps:

[0009] S1. First, use the ball milling process to grind copper powder, tin powder, aluminum powder, cuprous oxide, graphite, and molybdenum disulfide into powders. After grinding, use a sieve to screen. The unqualified powders are ground again until qualified.

[0010] S2. Pour the ground powders into a mixing device and use a stirring device to stir evenly.

[0011] S3. Pour the powder after stirring into the conductive pressure film, fix two electrode rods on both sides of the conductive pressure film, and apply a pulsed current through the two electrode rods during the pressure forming process to obtain a preform with a certain shape, size and density;

[0012] S4. Place the preform in S3 in a sintering mold, and apply a pulsed current to the sintering mold while sintering to accelerate the sintering of the metallurgical product;

[0013] S5. Wait for the metallurgical product to cool naturally to obtain the metallurgical product, and finally perform surface treatment on the metallurgical product.

[0014] Preferably, the grinding time in S1 is 10 - 25 minutes, and the mesh number of the sieve in S1 is 20 - 100 meshes.

[0015] Preferably, the stirring time in S2 is 20 - 30 minutes.

[0016] Preferably, the voltage of the pulsed current in S3 is 1 - 10V, and the current magnitude is 100 - 2000A.

[0017] Preferably, the voltage of the pulsed current in S4 is 3 - 20V, and the current magnitude is 500 - 5000A.

[0018] (III) Beneficial effects

[0019] The present invention provides a powder metallurgy product for improving friction performance and a preparation method thereof.

[0020] It has the following beneficial effects:

[0021] 1. In the present invention, by applying a pulsed current during the pressure forming process, the diffusion bonding between powder particles is enhanced, the density is increased, and the strength distribution of the metallurgical product is made uniform.

[0022] 2. In the present invention, by applying a pulsed current in combination with mechanical pressure during the sintering process, the Joule heating and diffusion bonding between powder particles are promoted, and local high temperature (plasma discharge effect) is generated at the particle contact points, promoting rapid sintering. The whole process can be completed within a few minutes to dozens of minutes, which not only reduces the sintering temperature but also greatly shortens the sintering time, being beneficial to improving the preparation efficiency. Specific embodiments

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0024] Example 1:

[0025] An embodiment of the present invention provides a powder metallurgy product for improving friction performance, comprising the following raw materials in parts by weight: 25 parts of copper powder, 7 parts of tin powder, 7 parts of aluminum powder, 7 parts of cuprous oxide, 13 parts of graphite, and 15 parts of molybdenum disulfide.

[0026] Among them, copper powder, tin powder, aluminum powder, and cuprous oxide are the basic raw materials of the metallurgy product. The combined use of copper powder and tin powder can improve the performance of the metallurgy product, enhance strength and corrosion resistance. The addition of aluminum powder can increase the high-temperature resistance, high specific strength, strong reducibility, and atmospheric corrosion resistance of the metallurgy product. Cuprous oxide is used to maintain the chemical stability of the metallurgy product;

[0027] Graphite and molybdenum disulfide are solid lubricants for the metallurgy product, mainly used to improve the mechanical strength of the metallurgy product itself and its friction performance.

[0028] A preparation method for a powder metallurgy product for improving friction performance includes the following specific steps:

[0029] S1. First, use the ball milling process to grind copper powder, tin powder, aluminum powder, cuprous oxide, graphite, and molybdenum disulfide into powders. After grinding, use a sieve to screen. The unqualified powders are ground again until they are qualified;

[0030] S2. Pour the ground powders into a mixing device and use a stirring device to stir evenly;

[0031] S3. Pour the stirred powders into a conductive pressure film, fix two electrode rods on both sides of the conductive pressure film, and apply a pulsed current through the two electrode rods during the pressure forming process to obtain a green compact with a certain shape, size, and density. The pressure applied is 50 MPa;

[0032] During the pressure forming process, passing a pulsed current can enhance the diffusion bonding between powder particles, improve the density, make the strength distribution of the metallurgy product uniform, and ensure the uniformization of the mechanical strength of the manufactured metal product.

[0033] S4. Place the green compact in S3 in a sintering mold, and apply a pulsed current to the sintering mold while sintering to accelerate the sintering of the metallurgy product;

[0034] Applying a pulsed current in combination with mechanical pressure during the sintering process promotes Joule heating and diffusion bonding between powder particles, generates local high temperatures (plasma discharge effect) at the particle contact points, and promotes rapid sintering. The entire process can be completed in a few minutes to dozens of minutes, not only reducing the sintering temperature but also greatly shortening the sintering time, which is beneficial to improving the preparation efficiency.

[0035] S5. After the metallurgical product is naturally cooled, the metallurgical product can be obtained, and finally the surface of the metallurgical product can be treated.

[0036] In S1, the grinding time is 25 minutes, the mesh number of the sieve is 50 mesh, in S2, the stirring time is 30 minutes, in S3, the voltage of the pulsed current is 4V, and the current magnitude is 400A. In S4, the voltage of the pulsed current is 8V, and the current magnitude is 850A.

[0037] Example Two:

[0038] An embodiment of the present invention provides a powder metallurgy product for improving friction performance, including the following raw materials in parts by weight: 25 parts of copper powder, 7 parts of tin powder, 7 parts of aluminum powder, 7 parts of cuprous oxide, 13 parts of graphite, and 15 parts of molybdenum disulfide.

[0039] A preparation method of a powder metallurgy product for improving friction performance includes the following specific steps:

[0040] S1. First, use the ball milling process to grind copper powder, tin powder, aluminum powder, cuprous oxide, graphite, and molybdenum disulfide into powders. After grinding, use a sieve to screen. The unqualified powders are ground again until qualified.

[0041] S2. Pour the ground powders into a mixing device and use a stirring device to stir evenly.

[0042] S3. Pour the stirred powders into a conductive pressure film, fix two electrode rods on both sides of the conductive pressure film, and apply a pulsed current through the two electrode rods during the pressure forming process to obtain a preform with a certain shape, size, and density. The pressure for pressing is 50 MPa.

[0043] S4. Place the preform in S3 in a sintering mold and apply a pulsed current to the sintering mold while sintering to accelerate the sintering of the metallurgical product.

[0044] S5. After the metallurgical product is naturally cooled, the metallurgical product can be obtained, and finally the surface of the metallurgical product can be treated.

[0045] In S1, the grinding time is 25 minutes, the mesh number of the sieve is 50 mesh, in S2, the stirring time is 30 minutes, in S3, the voltage of the pulsed current is 7V, and the current magnitude is 1200A. In S4, the voltage of the pulsed current is 14V, and the current magnitude is 3200A.

[0046] Example Three:

[0047] An embodiment of the present invention provides a powder metallurgy product for improving friction performance, comprising the following raw materials in parts by weight: 25 parts of copper powder, 7 parts of tin powder, 7 parts of aluminum powder, 7 parts of cuprous oxide, 13 parts of graphite, and 15 parts of molybdenum disulfide.

[0048] A preparation method of a powder metallurgy product for improving friction performance comprises the following specific steps:

[0049] S1. First, adopt a ball milling process to grind copper powder, tin powder, aluminum powder, cuprous oxide, graphite, and molybdenum disulfide into powders. After grinding, use a sieve to screen. The unqualified powders are ground again until qualified.

[0050] S2. Pour the ground powders into a mixing device and use a stirring device to stir evenly.

[0051] S3. Pour the stirred powders into a conductive pressure film, fix two electrode rods on both sides of the conductive pressure film, and apply a pulsed current through the two electrode rods during the pressure forming process to obtain a green compact with a certain shape, size, and density. The pressure for pressing is 50 MPa.

[0052] S4. Place the green compact in S3 in a sintering mold, and apply a pulsed current to the sintering mold while sintering to accelerate the sintering of the powder metallurgy product.

[0053] S5. Wait for the powder metallurgy product to cool naturally to obtain the powder metallurgy product, and finally perform surface treatment on the powder metallurgy product.

[0054] The grinding time in S1 is 25 minutes, the mesh number of the sieve in S1 is 50 meshes, the stirring time in S2 is 30 minutes, the voltage of the pulsed current in S3 is 9 V, the current magnitude is 1800 A, the voltage of the pulsed current in S4 is 18 V, and the current magnitude is 4500 A.

[0055] Comparative example:

[0056] Compared with Example 1, Example 2, and Example 3, the difference is that no pulsed current is applied during the pressing and sintering processes in the comparative example, and other preparation steps and raw materials used are the same.

[0057] Use the preparation methods of Example 1, Example 2, Example 3, and the comparative example to carry out powder metallurgy preparation, and record the total sintering time and temperature during the preparation process. At the same time, conduct friction tests on the powder metallurgy products prepared in Example 1, Example 2, Example 3, and the comparative example. The results are shown in Table 1:

[0058] Table 1

[0059]

[0060] It can be seen from the data in Table 1 that the preparation methods of Example 1, Example 2, and Example 3 can reduce the temperature during sintering, and at the same time greatly reduce the sintering time. In addition, the friction performance is relatively superior.

[0061] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A powder metallurgy product for improving frictional performance, characterized in that: It includes the following raw materials in parts by weight: 20-25 parts of copper powder, 3-7 parts of tin powder, 5-7 parts of aluminum powder, 3-7 parts of cuprous oxide, 12-13 parts of graphite, and 13-15 parts of molybdenum disulfide.

2. A method for preparing a powder metallurgy product with improved friction performance, according to the powder metallurgy product with improved friction performance described in claim 1, characterized in that: It includes the following specific steps: S1. First, use the ball milling process to grind copper powder, tin powder, aluminum powder, cuprous oxide, graphite, and molybdenum disulfide into powders. After grinding, use a sieve to screen. The unqualified powders are ground again until qualified. S2. Pour the ground powders into a mixing device and use a stirring device to stir evenly. S3. Pour the stirred powders into a conductive film. Fix two electrode rods on both sides of the conductive film. Apply a pulsed current through the two electrode rods during the pressure forming process to obtain a blank with a certain shape, size, and density. S4. Place the blank in S3 in a sintering mold. Apply a pulsed current to the sintering mold while sintering to accelerate the sintering of the metallurgical product. S5. Wait for the metallurgical product to cool naturally to obtain the metallurgical product. Finally, treat the surface of the metallurgical product.

3. The preparation method of a powder metallurgy product for improving friction performance according to claim 2, characterized in that: The grinding time in S1 is 10-25 minutes, and the mesh number of the sieve in S1 is 20-100 meshes.

4. A method for preparing a powder metallurgy product with improved friction performance according to claim 2, characterized in that: The stirring time in S2 is 20-30 minutes.

5. A method for preparing a powder metallurgy product with improved friction performance according to claim 2, characterized in that: The voltage of the pulsed current in S3 is 1-10V, and the current magnitude is 100-2000A.

6. The preparation method of a powder metallurgy product for improving friction performance according to claim 2, characterized in that: The voltage of the pulsed current in S4 is 3-20V, and the current magnitude is 500-5000A.

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