A method for preparing copper-based alloy powder

Abstract

The present invention discloses a copper-based alloy powder and a preparation method thereof, belonging to the technical field of alloy powders. The copper-based alloy powder has a mass percentage composition of: Al: 0.2-3.0 wt%, Y: 0.1-0.5 wt%, with the remainder being Cu and non-removable oxygen and impurity elements. The preparation method of the copper-based alloy powder comprises the following steps: smelting metallic copper under medium-frequency induction conditions to obtain a first melt; 2 adding an aluminum-copper master alloy and an aluminum-yttrium master alloy to the first melt and smelting and stirring them under low-frequency induction conditions to obtain a second melt; and dummying the second melt using a high-pressure gas-gas combined atomization device to obtain copper-based alloy powder. The copper-based alloy powder produced by the present invention has a narrow particle size distribution, a median particle size D50 ≤ 45 μm, an oxygen content ≤ 480 ppm, uniform distribution of aluminum and yttrium elements, and a high powder yield.

Description

Technical Field

[0001] The present invention relates to the technical field of alloy powders, and in particular to a copper-based alloy powder and a preparation method thereof. Background Art

[0002] Nano-oxide dispersion-strengthened copper alloy has excellent mechanical properties, electrical conductivity and resistance to high-temperature softening. It is one of the copper alloys with the best comprehensive performance. It is widely used in electronic devices, automotive industry, aerospace and new energy fields, and has good market prospects.

[0003] Oxide-dispersed copper-based alloys are increasingly widely used, but preparation technology remains a mystery. Technical bottlenecks primarily lie in powder preparation and oxidation processes, with significant gaps between these and international standards, particularly in terms of nano-reinforcement and stability. According to industry sources, the powder production process still relies on traditional induction melting followed by water atomization / gas atomization, a method commonly used in China. Oxide phases in dispersion-strengthened copper alloys include Al₂O₃, Y₂O₃, and ZrO. The primary production process involves alloy powder oxidation, which can be categorized as internal or external oxidation. In addition to the oxidation process, the uniformity of the distribution of elements like Al and Y in the copper matrix, powder particle size, and the content of primary coarse oxides in the alloy powder also play a decisive role in alloy performance. Therefore, quality control of atomized alloy powders is crucial. Generally speaking, the greater the number of dispersed elements in a copper alloy, the less uniform the distribution of the individual components, the wider the powder particle size distribution, and the more severe the segregation of dispersed elements on the copper surface. At present, the atomization methods of alloy powders mainly include water atomization, non-vacuum air atomization and vacuum air atomization. Among them, the alloy powder produced by water atomization has small particle size, irregular shape and high oxygen content. The oxide dispersion strengthened copper alloy produced has problems such as poor material processing performance; the alloy powder produced by non-vacuum / vacuum air atomization has good sphericity, large particle size and particle size distribution, and low oxygen content. Due to the influence of low cooling rate, the segregation of elements during the atomization process is more serious.

[0004] For the smelting and atomization of alloying elements with significantly different specific gravities, such as copper, aluminum, and yttrium, controlling element homogenization during smelting and minimizing segregation during atomization not only reduces the cost of subsequent oxidation process control but also contributes to further improving material properties. Furthermore, the synergistic use of two or more nano-oxide reinforcement phases is an important approach to enhancing the overall performance of materials.

[0005] Therefore, it is of great significance to provide a copper-based alloy powder with uniform element distribution, small powder particle size, narrow particle size, less primary coarse oxides and containing two dispersed elements and a preparation method thereof. Summary of the Invention

[0006] In response to the aforementioned shortcomings, the present invention provides a copper-based alloy powder and a method for preparing the same. This invention achieves uniform distribution of aluminum and yttrium in a copper melt through the synergistic combination of alloy composition design, coordinated stirring, and dual atomization. The addition of yttrium not only purifies the alloy melt but also forms a nanoscale Y2O3 strengthening phase during subsequent oxidation treatment, which synergistically disperses and strengthens the copper alloy with the Al2O3 strengthening phase. The dual atomization effectively addresses the issues of coarse powder particles, wide particle size distribution, and surface element segregation that often plague gas atomization processes. The copper-based alloy powder produced by the present invention exhibits a narrow particle size distribution, with a median particle size D50 ≤ 45 μm, an oxygen content ≤ 480 ppm, uniform distribution of aluminum and yttrium, and a high powder yield.

[0007] In order to achieve the above object, the present invention provides a copper-based alloy powder, wherein the mass percentage composition of the copper-based alloy powder is: Al: 0.2-3.0wt%, Y: 0.1-0.5wt%, and the balance is Cu and non-removable oxygen and impurity elements.

[0008] According to one aspect of the present invention, the oxygen content is ≤480 ppm.

[0009] According to one aspect of the present invention, the median particle size D50 of the copper-based alloy powder is ≤45 μm.

[0010] Based on the same inventive concept, the present invention also provides a method for preparing the above-mentioned copper-based alloy powder, comprising the following steps:

[0011] Step 1: Melting metallic copper under medium frequency induction conditions to obtain a first melt;

[0012] Step 2: adding an aluminum-copper master alloy and an aluminum-yttrium master alloy to the first melt, and performing smelting and stirring under low-frequency induction conditions to obtain a second melt; wherein the smelting and stirring are divided into two stages, the first stage adopts a second stirring mode, and the stirring time is 3 to 5 minutes; the second stage adopts an alternating stirring mode, and the alternating stirring mode is to cycle the first stirring and the second stirring, each stirring mode is maintained for 1 to 3 minutes, and the number of cycles is 2 to 4 times; the direction of the first stirring is that the upper layer melt flows upward from the center and flows downward from the side wall, and the lower layer melt flows upward from the side wall and flows downward from the center; the direction of the second stirring is that the melt flows upward from the side wall and flows downward from the center;

[0013] Step 3: The second melt is double-atomized by a high-pressure gas-gas combined atomization device to obtain a copper-based alloy powder;

[0014] Among them, double atomization includes the first atomization and the second atomization.

[0015] According to one aspect of the present invention, the smelting is carried out in an induction furnace with a power of 30 to 200 kW, a low-frequency induction frequency of 20 to 200 Hz, and a medium-frequency induction frequency of 900 to 1500 Hz.

[0016] According to one aspect of the present invention, in step 3, the atomization temperature is 1180-1400°C.

[0017] According to one aspect of the present invention, in step 3, the spray vertex angle of the auxiliary atomizer used for the first atomization is 0-3°, and the atomization pressure is 0.1-1.0 MPa; the spray vertex angle of the atomizer used for the second atomization is 30-45°, and the atomization pressure is 2-6 MPa.

[0018] According to one aspect of the present invention, the stirring mode is controlled by the induction circuit of the induction furnace itself.

[0019] According to one aspect of the present invention, the power of the first stirring is 40-50 kW and the frequency is 70-100 Hz, and the power of the second stirring is 50-70 kW and the frequency is 45-60 Hz.

[0020] Beneficial effects of the present invention:

[0021] The present invention achieves uniform distribution of copper, aluminum and yttrium elements with large differences in specific gravity through overall and local coordinated stirring of the melt; the addition of yttrium element can not only purify the alloy melt, but also form a nano-scale Y2O3 strengthening phase during subsequent oxidation treatment, and synergistically disperse the copper alloy with the Al2O3 strengthening phase, and the addition of two elements in the alloy composition design of the present application will not affect the uniform distribution of each component (Cu, Al, Y) and the segregation of Al and Y on the copper surface; the homogenized melt is pre-dispersed into multiple "brush-shaped" fibrous filamentous metal droplets during the first gas atomization process, and then is atomized and broken into small droplets for the second time by the ejected high-pressure atomizing airflow, thereby avoiding the segregation of aluminum and yttrium elements on the copper surface during atomization, that is, the present invention reduces the segregation of aluminum element from 15% to about 8%, and reduces the segregation of yttrium element from 19% to 10%. The copper-based alloy powder prepared by the invention has narrow particle size distribution, median particle size D50≤45μm, oxygen content≤480ppm, uniform distribution of aluminum and yttrium elements, and high powder yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for describing the embodiments or the prior art.

[0023] Figure 1 Schematic diagram of the first stirring method of the present invention;

[0024] Figure 2Schematic diagram of the second stirring method of the present invention;

[0025] Figure 3 This is a diagram of the copper-based alloy powder prepared in Example 1 of the present invention;

[0026] Figure 4 This is a diagram of the copper-based alloy powder prepared in Comparative Example 6 of the present invention;

[0027] Figure 5 This is the SEM image of the copper-based alloy powder prepared in Example 1. DETAILED DESCRIPTION

[0028] To make the present invention easier to understand, the present invention is further described below with reference to specific examples. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Unless otherwise defined, the professional terms used below are consistent with the meanings understood by professional and technical personnel in this field; unless otherwise specified, the raw materials and reagents involved in this article can be purchased from the market or prepared by known methods.

[0029] To address the technical problems encountered in the prior art, the present invention provides a copper-based alloy powder having a mass percentage composition of: Al: 0.2-3.0 wt%, Y: 0.1-0.5 wt%, with the remainder being Cu and unremovable oxygen and impurity elements. Preferably, the oxygen content is ≤ 480 ppm. Preferably, the copper-based alloy powder has a median particle size D50 ≤ 45 μm.

[0030] In order to solve the technical problems existing in the background technology, the present invention further provides a method for preparing the above-mentioned copper-based alloy powder, comprising the following steps:

[0031] Step 1: Melting metallic copper under medium frequency induction conditions to obtain a first melt;

[0032] Step 2: adding aluminum-copper master alloy and aluminum-yttrium master alloy to the first melt, and melting and stirring under low-frequency induction conditions to obtain a second melt; wherein the melting and stirring is divided into two stages, the first stage adopts the second stirring mode, and the stirring time is 3 to 5 minutes; the second stage adopts the alternating stirring mode, and the alternating stirring mode is to cycle the first stirring and the second stirring, each stirring mode is maintained for 1 to 3 minutes, and the number of cycles is 2 to 4 times; the direction of the first stirring is as follows Figure 1As shown, the upper melt flows upward from the center and downward from the side walls, and the lower melt flows upward from the side walls and downward from the center; the direction of the second stirring is as shown in FIG. Figure 2 As shown, the melt flows upward from the side wall and downward from the center;

[0033] Step 3: The second melt is double-atomized by a high-pressure gas-gas combined atomization device to obtain a copper-based alloy powder;

[0034] Among them, double atomization includes the first atomization and the second atomization.

[0035] Preferably, the smelting is carried out in an induction furnace, the power of the induction furnace is 30-200 kW, the low-frequency induction frequency is 20-200 Hz, and the medium-frequency induction frequency is 900-1500 Hz.

[0036] Preferably, in step 3, the atomization temperature is 1180-1400°C.

[0037] Preferably, in step 3, the spray vertex angle of the auxiliary atomizer used for the first atomization is 0-3°, and the atomization pressure is 0.1-1.0 MPa; the spray vertex angle of the atomizer used for the second atomization is 30-45°, and the atomization pressure is 2-6 MPa.

[0038] Preferably, the stirring mode is controlled by the induction circuit of the induction furnace itself.

[0039] Preferably, the power of the first stirring is 40-50 kW and the frequency is 70-100 Hz, and the power of the second stirring is 50-70 kW and the frequency is 45-60 Hz.

[0040] The following further describes the details in conjunction with specific embodiments.

[0041] Example 1

[0042] The materials are prepared according to the standard of 100kg, 0.4wt% Al, and 0.1wt% Y per heat. The copper metal is placed in an induction furnace and heated under medium-frequency induction (95-120kW, 900-1100Hz) until it is completely melted. Then, the master alloys Al-Cu (50% copper) and Al-Y (30% yttrium) are added. The induction furnace is set to low frequency operation and stirred in two stages. The first stage is the second stirring stage (50-70kW, 45-60Hz), with the melting temperature maintained at 1100°C-1150°C and stirring for 4 minutes. The second stage is coordinated stirring, with the first stirring stage (40-50kW, 70-100Hz) and the second stirring stage (50-70kW, 45-60Hz) being carried out in sequence. Each stage is operated for 2 minutes, and the cycle is repeated twice. The obtained copper-based alloy melt is atomized by a high-pressure gas-gas combined atomization device at an atomization temperature of 1200-1350°C. The spray vertex angle of the auxiliary atomizer used in the first atomization is 0° and the atomization pressure is 0.3 MPa; the spray vertex angle of the atomizer used in the second atomization is 35° and the atomization pressure is 4 MPa. The obtained powder is collected, which is the copper-based alloy powder. The actual figure is as follows Figure 3 As shown, its SEM picture is as follows Figure 5 As shown by Figure 5 It can be seen that the copper-based alloy powder prepared by the present invention has a narrow particle size distribution, uniform distribution of aluminum and yttrium elements, and a high powder yield.

[0043] Example 2

[0044] The difference between this embodiment and embodiment 1 is that the materials are prepared according to a single heat of 100 kg, 3.0 wt% Al, and 0.5 wt% Y. The remaining steps and parameters are the same as those in embodiment 1.

[0045] Example 3

[0046] The difference between this embodiment and embodiment 1 is that the second stage is coordinated stirring, and the first stirring stage (40-50 kW, 70-100 Hz) and the second stirring stage (50-70 kW, 45-60 Hz) are performed in sequence, each stage is run for 2 minutes, and the cycle is repeated 4 times. The remaining steps and parameters are the same as those in embodiment 1.

[0047] Comparative Example 1

[0048] The difference between this comparative example and Example 1 is that the materials are prepared according to a single heat of 100 kg and 0.4 wt% Al. The remaining steps and parameters are the same as those in Example 1.

[0049] Comparative Example 2

[0050] The difference between this comparative example and Example 1 is that the ingredients are prepared according to a single heat of 100 kg and 0.5 wt% Y. The remaining steps and parameters are the same as those in Example 1.

[0051] Comparative Example 3

[0052] The difference between this comparative example and Example 1 is that the stirring process is maintained at the low-frequency first stirring (40-50 kW, 70-100 Hz) throughout. The remaining steps and parameters are the same as those in Example 1.

[0053] Comparative Example 4

[0054] The difference between this comparative example and Example 1 is that the stirring process is maintained at the low-frequency second stirring (50-70 kW, 45-60 Hz) throughout. The remaining steps and parameters are the same as those in Example 1.

[0055] Comparative Example 5

[0056] This comparative example differs from Example 1 in that the copper-based alloy melt was atomized using a high-pressure gas atomization device at an atomization temperature of 1200-1350°C, a single atomization process, a 35° spray tip angle, and a 4 MPa atomization pressure. The remaining steps and parameters were the same as in Example 1.

[0057] Comparative Example 6

[0058] The difference between this comparative example and Example 1 is that the stirring process is maintained at low-frequency first stirring (40-50kW, 70-100HZ) throughout the entire process, the copper-based alloy melt is atomized by a high-pressure gas atomization device, the atomization temperature is 1200-1350°C, only one atomization process is performed, the spray vertex angle of the atomizer is 35°, and the atomization pressure is 4MPa. The remaining steps and parameters are the same as in Example 1. The copper-based alloy prepared by the method is as follows: Figure 4 shown.

[0059] The powders prepared in Examples 1-3 and Comparative Examples 1-6 were tested for composition and oxygen content, and the results are shown in Table 1:

[0060] Table 1 Test results of powder composition and oxygen content prepared in Examples 1-3 and Comparative Examples 1-6

[0061]

[0062]

[0063] As can be seen from Table 1, when the alloy composition design and atomization process are the same, the overall and local coordinated stirring of the alloy melt has a significant improvement effect on the homogenization of the element distribution; and when the alloy composition design and smelting process are the same, the secondary atomization process can suppress the atomization cooling segregation of the alloy elements. Increasing the content of the alloying elements or increasing the number of stirring cycles can reduce the degree of segregation of the elements. The former is caused by an increase in the base number, and the latter is caused by further improvement in the homogenization of the melt. As can be seen from Example 1 and Comparative Examples 1-2, relative to a single strengthening element, the multiple strengthening elements of the components of the present application combined with the stirring and atomization process of the present application can also achieve low segregation of Al and Y on the copper surface.

[0064] The powders prepared in Examples 1-3 and Comparative Examples 1-6 were subjected to particle size and morphology testing, and the results are shown in Table 2:

[0065] Table 2 Particle size and morphology test results of powders prepared in Examples 1-3 and Comparative Examples 1-6

[0066]

[0067] As shown in Table 2, the atomization process is a decisive factor in powder particle size. Compared with the primary atomization process, the addition of the auxiliary atomization process can significantly refine the alloy powder and improve the fine powder yield of the atomized powder. As shown in Example 1 and Comparative Examples 1-2, compared with a single strengthening element, the multiple strengthening elements of the components of the present application, combined with the stirring and atomization processes of the present application, can also achieve homogenization of each element.

[0068] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for preparing copper-based alloy powder, characterized in that: The mass percentage composition of the copper-based alloy powder is as follows: Al: 0.2-3.0 wt%, Y: 0.1-0.5 wt%, and the balance is Cu and unremovable oxygen and impurity elements; the preparation method comprises the following steps: Step 1: Melting metallic copper under medium frequency induction conditions to obtain a first melt; Step 2: adding an aluminum-copper master alloy and an aluminum-yttrium master alloy to the first melt, and performing smelting and stirring under low-frequency induction conditions to obtain a second melt; wherein the smelting and stirring are divided into two stages, the first stage adopts a second stirring mode, and the stirring time is 3 to 5 minutes; the second stage adopts an alternating stirring mode, and the alternating stirring mode is to cycle the first stirring and the second stirring, each stirring mode is maintained for 1 to 3 minutes, and the number of cycles is 2 to 4 times; the direction of the first stirring is that the upper layer melt flows upward from the center and flows downward from the side walls, and the lower layer melt flows upward from the side walls and flows downward from the center; the direction of the second stirring is that the melt flows upward from the side walls and flows downward from the center; Step 3: The second melt is double-atomized by a high-pressure gas-gas combined atomization device to obtain a copper-based alloy powder; Among them, double atomization includes the first atomization and the second atomization; the atomization pressure of the first atomization is 0.1~1.0MPa; the atomization pressure of the second atomization is 2~6MPa.

2. The method for preparing copper-based alloy powder according to claim 1, wherein: The smelting is carried out in an induction furnace with a power of 30-200KW, a low-frequency induction frequency of 20-200HZ, and a medium-frequency induction frequency of 900-1500HZ.

3. The method for preparing copper-based alloy powder according to claim 1, wherein: In step 3, the atomization temperature is 1180~1400℃.

4. The method for preparing copper-based alloy powder according to claim 1, wherein: In step 3, the spray vertex angle of the auxiliary atomizer used for the first atomization is 0-3°; the spray vertex angle of the atomizer used for the second atomization is 30-45°.

5. The method for preparing copper-based alloy powder according to claim 1, wherein: The stirring mode is controlled by the induction circuit of the induction furnace itself.

6. The method for preparing copper-based alloy powder according to claim 1, wherein: The power of the first stirring is 40-50 kW and the frequency is 70-100 Hz, and the power of the second stirring is 50-70 kW and the frequency is 45-60 Hz.

7. The method for preparing copper-based alloy powder according to claim 1, wherein: The oxygen content is ≤480 ppm.

8. The method for preparing copper-based alloy powder according to claim 1, wherein: The median particle size D50 of the copper-based alloy powder is ≤45 μm.

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