High-density silver-based component and preparation method and application thereof

Abstract

The invention provides a high-density silver-based component and a preparation method and application thereof, and belongs to the technical field of metal component preparation. The preparation method of the high-density silver-based component comprises the following steps that metal powder is provided, and the metal powder comprises, by mass, 1-6% of copper and the balance silver; and the metal powder is subjected to selective laser melting forming, the high-density silver-based component is obtained, and the density of the high-density silver-based component is larger than or equal to 97.7%. By the adoption of the method, the high-density silver-based component with the density larger than or equal to 97.7% can be prepared, operation is easy, and cost is low.

Description

Technical Field

[0001] This invention relates to the field of metal component manufacturing technology, and in particular to a high-density silver-based component, its manufacturing method, and its application. Background Technology

[0002] Selective laser melting (SLM) technology, as an important metal additive manufacturing technology, is widely used in aerospace, medical, and mold manufacturing fields because it is not bound by fixed molds and can directly manufacture metal components with complex geometries. Precious metals like silver and their alloys have irreplaceable application prospects in high-end electronic contacts, radio frequency devices, and heat exchangers due to their excellent electrical and thermal conductivity. However, due to the high cost of silver raw materials, traditional subtractive manufacturing techniques result in significant material loss and low processing efficiency. In contrast, SLM technology, as a near-net-shape forming process, can significantly improve material utilization and shorten manufacturing cycles through digital rapid prototyping capabilities, thereby reducing precious metal loss and overall production costs from the source.

[0003] However, compared to non-precious metals (such as aluminum, magnesium, and titanium), pure silver has a high reflectivity to near-infrared lasers, resulting in most of the incident laser energy not being effectively absorbed by the silver, leading to extremely low energy utilization. Therefore, during SLM production, the pure silver molten pool is prone to "spheroidization," resulting in numerous voids and unfused defects within the component, severely affecting its density and consequently reducing its mechanical properties. Surface modification of pure silver powder can improve its laser forming performance, but this method is often complex, costly, and can affect the surface quality of the component. Furthermore, increasing the laser power density can also improve the laser forming performance of silver to some extent, but the improvement is limited. For example, with a laser power of 350W, a scanning speed of 400mm / s, and a scanning interval of 0.05mm, the density of components prepared from pure silver powder is still ≤97%. If the laser power density is further increased, the molten pool will bulge due to excessive energy during the forming process, making subsequent printing impossible. Summary of the Invention

[0004] The purpose of this invention is to provide a high-density silver-based component, its preparation method and application. The method of this invention can prepare a high-density silver-based component with a density ≥97.7%, and the operation is simple and the cost is low.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing a highly dense silver-based component, comprising the following steps: The metal powder provided comprises, by mass fraction, 1-6% copper and the balance silver; The metal powder is subjected to selective laser melting to form a high-density silver-based component, wherein the density of the high-density silver-based component is ≥97.7%.

[0006] Preferably, the laser used for laser selective melting and forming is an infrared laser, and the scanning method is a checkerboard scanning.

[0007] Preferably, the conditions for laser selective melting forming include: laser power of 200~400W, scanning speed of 300~800mm / s, scanning spacing of 0.02~1.00mm, and powder thickness of 0.01~0.06mm.

[0008] Preferably, the conditions for laser selective melting forming include: laser power of 350~400W, scanning speed of 600~800mm / s, scanning spacing of 0.04~0.08mm, and powder thickness of 0.02~0.04mm.

[0009] Preferably, the substrate material used in the laser selective melting forming includes stainless steel, and the substrate is not preheated during the laser selective melting forming process.

[0010] Preferably, the metal powder has a particle size of 15~53μm and a purity of ≥99.9wt%; the metal powder is a mixture of silver powder and copper powder, or a silver-copper alloy powder.

[0011] Preferably, when the metal powder is a mixture of silver powder and copper powder, the method for preparing the metal powder includes the following steps: mixing silver powder and copper powder and then sequentially ball milling and drying to obtain the metal powder.

[0012] Preferably, the silver powder and copper powder are prepared by vacuum atomization; the ball milling conditions include: a ball-to-material ratio of 3~5:1, a ball milling frequency of 5~8Hz, and a ball milling time of 8~12h; the drying is vacuum drying, with a temperature of 80~110℃, a time of 10~15h, and a vacuum degree of 10. -3 ~10 -5 Pa.

[0013] The present invention provides a high-density silver-based component prepared by the preparation method described in the above technical solution.

[0014] This invention provides the application of the high-density silver-based component described above in sputtering targets.

[0015] Beneficial Effects: By adding copper, which has a higher absorption rate for infrared lasers, this invention significantly improves the absorption rate of metal powder to laser energy, reduces the critical laser power required for selective laser melting (SLM), and broadens the process window. This effectively addresses the problems of high laser reflectivity and low density of silver-based components in pure silver materials. The resulting high-density silver-based components have a density ≥97.7%, which is beneficial for improving the mechanical and thermal properties of silver-based components while maintaining good electrical conductivity. Furthermore, the method of this invention is simple to operate, has low processing costs, and improves material utilization and component yield, significantly reducing the production cost of high-value precious metal silver-based components. It has great application and research prospects in high-end electronics, communications, and aerospace fields. Attached Figure Description

[0016] Figure 1 This is a process flow diagram of the fabrication of high-density silver-based components based on laser selective melting forming technology in an embodiment of the present invention; Figure 2 The X-ray diffraction patterns of the silver-based components in Examples 1, 4 and Comparative Example 1 are shown. Figure 3 The images shown are scanning electron microscope (SEM) images of the silver-based components in the various embodiments and comparative examples. Detailed Implementation

[0017] This invention provides a method for preparing a highly dense silver-based component, comprising the following steps: The metal powder provided comprises, by mass fraction, 1-6% copper and the balance silver; The metal powder is subjected to selective laser melting to form a high-density silver-based component, wherein the density of the high-density silver-based component is ≥97.7%.

[0018] In this invention, unless otherwise specified, all raw materials used are commercially available products well known to those skilled in the art or prepared using methods well known to those skilled in the art.

[0019] This invention provides a metal powder comprising, by mass fraction, 1-6% copper and the balance silver. The specific mass fraction of copper in the metal powder can be 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, or 6%. By adding copper during the preparation of high-density silver-based components, this invention effectively suppresses "spheroidization" and incomplete fusion defects caused by insufficient energy absorption. The addition of copper promotes the wetting and spreading of the surrounding silver in the molten pool, resulting in more stable molten pool behavior and denser interlayer bonding. By controlling the amount of copper added within the above-mentioned range, the resulting high-density silver-based components have a density ≥97.7%, which is beneficial for improving the mechanical and thermal conductivity of the silver-based components while maintaining good electrical conductivity. Specifically, copper has a lower electrical conductivity than silver. Therefore, when the copper content is too high, it will lead to an increase in the resistance of highly dense silver-based components. For metal samples of the same size and shape, the higher the density, the lower the resistance. When the copper content is low, the resistance can still reach the level of pure silver after the product density is increased. However, when the copper content is high, it will lead to a decrease in the conductivity of the product.

[0020] In one embodiment of the present invention, the metal powder has a particle size of 15-53 μm and a purity ≥99.9 wt%; the metal powder is a mixture of silver powder and copper powder, or a silver-copper alloy powder, preferably a mixture of silver powder and copper powder. In another embodiment of the present invention, when the metal powder is a mixture of silver powder and copper powder, the preparation method of the metal powder includes the following steps: mixing silver powder and copper powder and then sequentially ball milling and drying to obtain the metal powder. In another embodiment of the present invention, the particle size of both the silver powder and copper powder is preferably in the range of 15-53 μm, and the purity is preferably ≥99.9 wt%; the silver powder and copper powder can be prepared by vacuum atomization, and the silver powder and copper powder prepared by vacuum atomization have good sphericity, thus giving them good flowability. The present invention does not specifically limit the operation steps and conditions of the vacuum atomization method, as long as the silver powder and copper powder meeting the above requirements are obtained.

[0021] In one embodiment of the present invention, the ball milling conditions include: a ball-to-powder ratio of 3 to 5:1, specifically 3:1, 4:1, or 5:1, where the ball-to-powder ratio is the mass ratio of grinding balls to metal powder, and the grinding balls are specifically zirconia grinding balls; a ball milling frequency of 5 to 8 Hz, specifically 5 Hz, 6 Hz, 7 Hz, or 8 Hz; and a ball milling time of 8 to 12 hours, specifically 8 hours, 9 hours, 10 hours, 11 hours, or 12 hours; preferably, the process is paused for 10 minutes every hour of ball milling. In this embodiment, silver powder, copper powder, and grinding balls are placed in a polytetrafluoroethylene ball milling jar and ball milled using a planetary ball mill under the above conditions. The present invention, by ball milling silver powder and copper powder under the above conditions, can break up any agglomerates that may exist in the silver and copper powders, ensuring that they are fully mixed and evenly dispersed.

[0022] In one embodiment of the present invention, the drying can be vacuum drying, and the vacuum drying temperature can be 80~110℃, specifically 80℃, 90℃, 100℃ or 110℃; the time can be 10~15h, specifically 10h, 11h, 12h, 13h, 14h or 15h; the vacuum degree can be 10. -3 ~10 -5 Pa, specifically 10 -3 Pa, 10 -4 Pa or 10 -5 Pa. In this embodiment of the invention, the vacuum drying is specifically performed in a vacuum oven. After vacuum drying, it is preferable to wait for the temperature of the vacuum oven to drop to room temperature before opening the vacuum oven and removing the obtained metal powder. This invention removes moisture adhering to the metal powder through drying, which is beneficial for improving the flowability of the metal powder.

[0023] After obtaining the metal powder, the present invention performs selective laser melting to form a high-density silver-based component, wherein the density of the high-density silver-based component is ≥97.7%. In one embodiment of the present invention, the laser used for selective laser melting can be an infrared laser, and the scanning method can be a checkerboard scanning method. By employing an infrared laser and a checkerboard scanning method, the present invention can achieve precise control of the heat input of the molten pool and significantly reduce residual stress, which is beneficial for obtaining a fine-grained, uniformly composed microstructure, thereby significantly improving the density of the silver-based component.

[0024] In one embodiment of the present invention, the substrate material used for the laser selective melting forming may include stainless steel, specifically 316L stainless steel; the substrate is not preheated during the laser selective melting forming. In another embodiment of the present invention, the conditions for the laser selective melting forming include: laser power of 200~400W, specifically 200W, 230W, 250W, 280W, 300W, 330W, 350W, 380W, or 400W; and scanning speed of 300~800mm / s, specifically 300mm / s, 350mm / s, 400mm / s, 450mm / s, 500mm / s, 550mm / s, 600mm / s, 650mm / s, or 700mm / s. The laser speed can be 750 mm / s or 800 mm / s; the scanning interval can be 0.02~1.00 mm, specifically 0.02 mm, 0.03 mm, 0.04 mm, 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.10 mm, 0.50 mm or 1.00 mm; the powder thickness can be 0.01~0.06 mm, specifically 0.01 mm, 0.02 mm, 0.03 mm, 0.04 mm, 0.05 mm or 0.06 mm. Under the above conditions, this invention uses laser selective melting to form the metal powder, which can effectively reduce the residual stress inside the product, control its microstructure, and reduce cracks and shrinkage cavities generated during the preparation process. Therefore, high-density, high-quality silver-based components can be obtained with relatively low laser power.

[0025] In one embodiment of the present invention, the metal powder is placed in the feed chamber of a laser selective melting and forming printing device, ensuring that the metal powder is flush with the top of the feed chamber. Then, in a protective atmosphere (such as argon), the metal powder is layered onto the substrate in the forming chamber using a powder-laying arm. An infrared laser is applied as a heat source, and laser selective melting and forming is performed using a checkerboard scanning method to obtain the high-density silver-based component. In another embodiment, the laser selective melting and forming printing device can be an HBD-150 printer manufactured by Hanbang Laser; the dimensions of the high-density silver-based component in this embodiment can be 5mm × 5mm × 5mm.

[0026] As one embodiment of the present invention, after the laser selective melting and forming is completed, preferably after the product temperature drops to room temperature, the product is cut off from the substrate using an electrical discharge wire cutting device to obtain the high-density silver-based component.

[0027] This invention provides a high-density silver-based component prepared by the preparation method described in the above technical solution. The high-density silver-based component of this invention has a density ≥97.7%, further preferably 97.7%~99.3%, specifically 97.7%, 98.1%, 98.5%, 98.7%, 99.1%, or 99.3%; and a resistivity of 0.13~0.27 mΩ, specifically 0.13 mΩ, 0.18 mΩ, 0.20 mΩ, 0.22 mΩ, or 0.27 mΩ.

[0028] This invention provides the application of the high-density silver-based component described above in sputtering targets.

[0029] Figure 1 This is a process flow diagram for preparing high-density silver-based components based on laser selective melting technology in an embodiment of the present invention. The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0030] Example 1 The method for preparing high-density silver-based components based on laser selective melting technology in this embodiment includes the following steps: (1) Silver and copper powder with a purity ≥99.9wt% and a particle size of 15~53μm were prepared by vacuum atomization as raw materials. The silver powder, copper powder and zirconia grinding balls were placed in a polytetrafluoroethylene ball milling jar, wherein the mass of copper powder was 2.5% of the total mass of silver powder and copper powder, and the mass ratio of the zirconia grinding balls to the total mass of silver powder and copper powder (i.e., the ball-to-material ratio) was 5:1. A planetary ball mill was used, and the ball milling was carried out for 12 hours at a frequency of 6Hz, with a 10-minute pause every 1 hour of ball milling. After the ball milling was completed, the obtained ball milled metal powder was taken out and placed in a vacuum oven at a vacuum degree of 10 -5 The dried metal powder was dried at 100℃ for 12 hours under Pa conditions. After the temperature of the vacuum oven dropped to room temperature, the vacuum oven was opened and the dried metal powder was taken out. (2) Place the dried metal powder in the feed hopper of the laser selective melting forming printer (specifically, the HBD-150 printer), ensuring that the dried metal powder is flush with the top of the feed hopper; then, in an argon atmosphere, spread the dried metal powder layer by layer onto the 316L stainless steel substrate (without preheating) in the forming hopper using a powder spreading arm, apply an infrared laser and perform laser selective melting forming using a checkerboard scanning method. The conditions for laser selective melting forming include: laser power of 250W, scanning speed of 500mm / s, scanning spacing of 0.05mm, and powder thickness of 0.02mm; after the laser selective melting forming is completed, wait for the temperature to drop to room temperature, and use an electrical discharge wire cutting device to cut the obtained product from the 316L stainless steel substrate to obtain a high-density silver-based component (size 5mm×5mm×5mm).

[0031] Example 2 The operation is the same as in Example 1, except that the laser power is 300W and the scanning speed is 600mm / s in this example.

[0032] Example 3 The operation is the same as in Example 1, except that the laser power is 350W and the scanning speed is 600mm / s in this example.

[0033] Example 4 The operation is the same as in Example 1, except that the mass of copper powder in this example is 5% of the total mass of silver powder and copper powder.

[0034] Example 5 The operation is the same as in Example 1, except that: in this example, the mass of copper powder is 5% of the total mass of silver powder and copper powder, the laser power is 300W and the scanning speed is 600mm / s.

[0035] Example 6 The operation is the same as in Example 1, except that: in this example, the mass of copper powder is 5% of the total mass of silver powder and copper powder, the laser power is 350W and the scanning speed is 600mm / s.

[0036] Comparative Example 1 The procedure is the same as in Example 1, except that copper powder is omitted in this comparative example, and only silver powder is used as the raw material to prepare silver-based components.

[0037] Comparative Example 2 The operation is the same as in Example 1, except that copper powder is omitted in this comparative example, that is, only silver powder is used as the raw material to prepare silver-based components, and the laser power is adjusted to 300W and the scanning speed is 600mm / s.

[0038] Comparative Example 3 The operation is the same as in Example 1, except that copper powder is omitted in this comparative example, that is, only silver powder is used as the raw material to prepare silver-based components, and the laser power is adjusted to 350W and the scanning speed is 600mm / s.

[0039] Test Example 1 Figure 2 The X-ray diffraction patterns of the silver-based components in Examples 1, 4, and Comparative Example 1 are shown. The results show that the phases of the silver-based components obtained by adding 2.5 wt% copper powder in Example 1, the silver-based components obtained by adding 5 wt% copper powder in Example 4, and the silver-based components obtained by using only silver powder in Comparative Example 1 are all relatively pure, with no second phase generated.

[0040] Figure 3 The table shows the surface scanning electron microscope (SEM) images of the silver-based components in each embodiment and comparative example. Table 1 shows the density and resistance test results of the silver-based components prepared in each embodiment and comparative example. Specifically, the density was tested using the Archimedes drainage method and the resistance was tested using the four-probe resistance test method. The results showed that, due to the low laser energy input, the surface of the silver-based component in Example 1 exhibited a certain degree of "spheroidization," with a density of 97.7% and a resistivity of 0.20 mΩ. In Example 2, the surface "spheroidization" of the silver-based component was improved, with a density of 98.1% and a resistivity of 0.18 mΩ. In Example 3, the interlayer bonding of the silver-based component was good, and the "spheroidization" phenomenon was further improved, with a density of 99.1% and a resistivity of 0.13 mΩ. In Example 4, with the copper powder addition increased to 5 wt%, the interlayer bonding of the silver-based component was good, with less "spheroidization," a density of 98.7%, and a resistivity of 0.22 mΩ. In Example 5, the interlayer bonding of the silver-based component was good, with almost no "spheroidization," a density of 99.3%, and a resistivity of 0.22 mΩ. In Example 6, the interlayer bonding of the silver-based component was good, with almost no "spheroidization," a density of 98.5%, and a resistivity of 0.27 mΩ. In Comparative Example 1, without the aid of copper melting, the resulting silver-based component exhibited severe "spheroidization," resulting in a density of only 92.8%. In Comparative Example 2, the silver-based component also showed severe "spheroidization," leading to a density of only 94.7%. In Comparative Example 3, increasing the laser energy input somewhat improved the "spheroidization" of the resulting silver-based component, but the density was still only 96.3%. Furthermore, under the same laser parameters, the silver-based components prepared by adding copper powder in Examples 1-6 showed good interlayer bonding, with almost no visible interlayer bonding traces, resulting in good overall integrity. In contrast, the silver-based components prepared using pure silver powder in Comparative Examples 1-3 exhibited obvious cracks and voids between layers, indicating poor interlayer bonding and consequently, a decrease in density.

[0041] Table 1 shows the density and resistivity test results of the silver-based components in each embodiment and comparative example.

[0042] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a high-density silver-based component, comprising the following steps: providing a metal powder, the metal powder comprising 1-6% copper and the balance silver in terms of mass fraction; and laser selective melting the metal powder to form a high-density silver-based component, the high-density silver-based component having a density of ≥97.7%. The laser used in the laser selective melting is an infrared laser, and the scanning mode is a chessboard scanning mode. The laser selective melting is performed under the following conditions: a laser power of 200-400 W, a scanning speed of 300-800 mm / s, a scanning interval of 0.02-1.00 mm, and a powder laying thickness of 0.01-0.06 mm.

2. The production method according to claim 1, characterized by, The laser selective melting is performed under the following conditions: a laser power of 350-400 W, a scanning speed of 600-800 mm / s, a scanning interval of 0.04-0.08 mm, and a powder laying thickness of 0.02-0.04 mm.

3. The production method according to claim 1 or 2, characterized by, The substrate material used in the laser selective melting comprises stainless steel, and the substrate is not preheated during the laser selective melting.

4. The production method according to claim 3, characterized by, The metal powder has a particle size of 15-53 μm and a purity of ≥99.9 wt%, and is a mixture of silver powder and copper powder or a silver-copper alloy powder.

5. The preparation method according to claim 3, characterized in that, When the metal powder is a mixture of silver powder and copper powder, the metal powder is prepared by mixing silver powder and copper powder, and then sequentially performing ball milling and drying.

6. The method of claim 1, wherein, 9.A high-density silver-based component prepared by the method of any one of claims 1-8.

7. The production method according to claim 6, characterized by, 10.Use of the high-density silver-based component of claim 9 in a sputtering target.

8. The method of claim 7, wherein, The silver powder and the copper powder are prepared by a vacuum gas atomization method; the ball milling conditions include that the ball-to-material ratio is 3-5:1, the ball milling frequency is 5-8 Hz, and the ball milling time is 8-12 h; the drying is vacuum drying, the temperature of the vacuum drying is 80-110 DEG C, the time is 10-15 h, and the vacuum degree is 10 -3 ~10 -5 Pa. ​ ​

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