High-entropy alloy particle reinforced copper-based contact material, preparation method and application thereof

Abstract

The application discloses a high-entropy alloy particle reinforced copper-based contact material and a preparation method and application thereof, and belongs to the technical field of contact materials. The application adds a reinforcing phase high-entropy particle into a copper base to improve the anti-ablation performance of the contact material. The application mixes powders of five different elements, ball-mills, anneals, and obtains high-entropy alloy powder, then mixes copper powder and the high-entropy alloy powder, ball-mills, and obtains Cu-HEAs composite powder, and finally adopts SPS hot-pressing sintering technology to obtain the high-entropy alloy reinforced copper-based contact material. The Cu-HEAs contact material has excellent physical and mechanical properties, enhances the anti-arc erosion performance of the copper-based contact material, and prolongs the service life of the contact.

Description

Technical Field

[0001] This invention belongs to the field of contact material technology, specifically relating to a high-entropy alloy particle-reinforced copper-based contact material, its preparation method, and its application. Background Technology

[0002] Electrical contact materials are an important component of electrical systems, mainly used in switches, relays, and circuit breakers. CuCr alloys are widely used in vacuum circuit breakers due to their high voltage withstand strength, large breaking current capacity, good resistance to welding, and low current-cutting performance. However, CuCr contacts have some shortcomings in terms of breaking capacity, current-cutting level, corrosion resistance, and resistance to welding. Therefore, it is imperative to develop contact materials with excellent comprehensive performance.

[0003] In recent years, high entropy alloys (HEAs) have attracted increasing attention due to their unique composition and microstructure. HEAs possess high strength, high hardness, and good high-temperature stability. Furthermore, the lattice distortion effect of HEAs increases electron scattering during energization, leading to increases in binding energy and work function. Therefore, high entropy alloys exhibit excellent resistance to arc erosion and welding.

[0004] This patent incorporates HEAs into copper-based contacts, studies the breaking capacity, retention level, arc erosion resistance, and anti-welding performance of Cu-HEAs, and analyzes the role of HEAs in these contacts. Summary of the Invention

[0005] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0006] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0007] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing a copper-based contact material reinforced with high-entropy alloy particles.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solutions, including:

[0009] The alloy powders were weighed separately, and after being degreased and dried, they were mixed and ball-milled once, and then annealed to obtain HEAs powder.

[0010] After degreasing, cleaning and drying, Cu powder and HEAs powder are mixed and ball-milled a second time to obtain Cu-HEAs composite powder.

[0011] Cu-HEAs composite powder was plasma hot-pressed and sintered under vacuum conditions to obtain a high-entropy alloy-reinforced copper-based contact material.

[0012] The Cu-HEAs composite powder contains 80–95 wt.% Cu powder and 5–20 wt.% HEAs powder.

[0013] As a preferred embodiment of the preparation method of the high-entropy alloy particle-reinforced copper-based contact material of the present invention, the alloy includes one or more of Co, Cr, Fe, Ni, Cu, Mn, and Al.

[0014] In a preferred embodiment of the preparation method of the high-entropy alloy particle-reinforced copper-based contact material of the present invention, the particle size of the alloy powder is 30-60 μm.

[0015] In a preferred embodiment of the preparation method of the high-entropy alloy particle-reinforced copper-based contact material of the present invention, the alloy powder is mixed in an equiatomic ratio manner.

[0016] In a preferred embodiment of the preparation method of the high-entropy alloy particle-reinforced copper-based contact material of the present invention, the first ball milling is performed using zirconia grinding balls with a ball-to-material ratio of 10-20:1, anhydrous ethanol as the grinding medium, a grinding speed of 500-1000 rpm, and a grinding time of 0-30 h.

[0017] In a preferred embodiment of the preparation method of the high-entropy alloy particle-reinforced copper-based contact material of the present invention, the annealing is carried out at a temperature of 400–600°C for 1–3 hours.

[0018] In a preferred embodiment of the preparation method of the high-entropy alloy particle-reinforced copper-based contact material of the present invention, the high-energy ball milling is performed at a speed of 100-300 rpm for a time of 0-3 hours.

[0019] As a preferred embodiment of the preparation method of the high-entropy alloy particle-reinforced copper-based contact material of the present invention, the process parameters of the plasma hot pressing sintering are: sintering temperature of 700-900℃, sintering pressure of 2.2-4.2MPa, heating rate of 20-50℃ / min, and sintering time of 0.5-1.5h; the drying temperature is 40-60℃.

[0020] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-entropy alloy particle-reinforced copper-based contact material.

[0021] The purpose of this invention is to overcome the shortcomings of the prior art and provide an application of high-entropy alloy particle-reinforced copper-based contact material in the fabrication of high-voltage switches.

[0022] Beneficial effects of this invention:

[0023] This invention utilizes high-energy ball milling to prepare HEAs powder with a dual-phase structure, which is then uniformly mixed with copper powder and sintered by spark plasma sintering to produce a novel Cu-HEAs contact material with a uniform and compact microstructure and HEAs particles evenly dispersed within the copper matrix. The novel Cu-HEAs contact material exhibits excellent mechanical properties, arc erosion resistance, and voltage withstand strength, providing a new approach for the preparation of copper-based contact materials. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0025] Figure 1 This is a simplified flowchart of the preparation method of the present invention.

[0026] Figure 2 The image shows an electron microscope image of the contact material prepared in Example 1. Detailed Implementation

[0027] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0028] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0029] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0030] Unless otherwise specified, all raw materials used in this invention are commercially available.

[0031] The materials obtained in the embodiments of the present invention were subjected to performance testing according to the following method:

[0032] The density of the contacts was measured using a density meter (MH-300G, Shanghai Shuju Instrument Technology Co., Ltd.) based on Archimedes' principle. The conductivity of the contacts was measured using an eddy current conductivity meter (FD-102, Xiamen Fuste Electronic Technology Co., Ltd.). The hardness of the samples was measured at room temperature using a Vickers hardness tester (MH-3, Jitai Scientific Instruments), with an applied load of 100g and a loading time of 3s. The contact alloy before and after arc erosion was weighed using an electronic balance (ME204E, METTLERTOLEDO, Switzerland), and the change in mass was calculated.

[0033] Example 1

[0034] This embodiment provides a method for preparing a high-entropy alloy particle-reinforced copper-based contact material, referring to... Figure 1 Specifically:

[0035] (1) Preparation of high entropy alloy (HEAs) powder

[0036] Weigh out 2.14g Cu powder, 2.13g Co powder, 2.13Ni powder, 1.72g Cr powder, and 1.88g Fe powder, with a particle size of 30-60μm. Remove oil from each powder, then wash with anhydrous ethanol and deionized water. Dry the powders under vacuum at 50℃. Mix the powders and place them in a ball mill jar. Add zirconia balls, controlling the ball-to-powder ratio at 15:1. Add 1.5g of anhydrous ethanol. Set the ball mill speed to 900 rpm and the milling time to 24h. Anneal the milled powder in a tube furnace at 500℃ for 2h to obtain HEAs powder.

[0037] (2) Preparation of Cu-HEAs composite powder

[0038] Weigh 8.5g Cu powder and 1.5g HEAs powder. Degrease the Cu powder, then wash it with anhydrous ethanol and deionized water, and then dry the powder at 50°C under vacuum. Mix the Cu powder and HEAs powder, place them in a ball mill jar, and perform high-energy ball milling. Set the ball milling speed to 200 rpm and the ball milling time to 0.5 h to obtain Cu-HEAs composite powder.

[0039] (3) Preparation of high-entropy alloy reinforced copper-based contact materials

[0040] Cu-HEAs composite powder was placed in a graphite mold with a diameter of 20 mm, and then the graphite mold was placed in a plasma hot pressing sintering furnace. Vacuum was drawn and the sintering process was set. The sintering pressure was set to 3.2 MPa, the sintering temperature to 800℃, the heating rate to 35℃ / min, and the sintering time to 1 h. After the process was completed, a high-entropy alloy reinforced copper-based contact material was obtained.

[0041] Figure 2 The electron micrograph of the contact material prepared in this embodiment shows that the microstructure of the Cu-HEAs contact material is uniform and compact, and the HEAs particles are uniformly dispersed in the copper matrix.

[0042] The sample prepared in this embodiment has a relative density of 90.7%, a conductivity of 34.2% IACS, and a hardness of 72.3 HV, which fully meet the technical requirements.

[0043] Example 2

[0044] The difference between this embodiment and Embodiment 1 is that the sintering pressure is adjusted from 3.2 MPa to 2.2 MPa, while the rest of the preparation process is the same as in Embodiment 1, to obtain a high-entropy alloy particle-reinforced copper-based contact material.

[0045] Example 3

[0046] The difference between this embodiment and Embodiment 1 is that the sintering pressure is adjusted from 3.2 MPa to 4.2 MPa, while the rest of the preparation process is the same as in Embodiment 1, to obtain a high-entropy alloy particle-reinforced copper-based contact material.

[0047] Comparative Example 1

[0048] The difference between this comparative example and Example 1 is that the sintering pressure was adjusted from 3.2 MPa to 1.2 MPa, while the rest of the preparation process was the same as in Example 1, resulting in a high-entropy alloy particle-reinforced copper-based contact material.

[0049] During the sintering process, if the sintering pressure is too low, a porous structure will exist inside the sample, making it impossible to obtain a uniform and dense sample, which will affect the performance of the sample.

[0050] The performance of the materials prepared in the above embodiments was tested, and the comparison results with those of Example 1 are shown in Table 1.

[0051] Table 1

[0052] relative density conductivity hardness Mass loss after arc erosion Example 1 90.7％ 34.2% IACS 72.3HV 0.05mg Example 2 86.3％ 30.4% IACS 60.7HV 0.11mg Example 3 90.1％ 33.1% IACS 71.3HV 0.08mg Comparative Example 1 79.9％ 23.1% IACS 57.5HV 0.17mg

[0053] As shown in the table above, adjusting the sintering pressure has a significant impact on the properties of copper-based contact materials. This is because during the sintering process, the sintering pressure promotes particle rearrangement, reduces the number and size of pores, and results in a more uniform and dense structure. Insufficient pressure may lead to a porous structure, while excessive pressure may cause particle deformation. The size and number of pores directly affect the material's hardness and electrical conductivity. Based on the results in the table above, the optimal technical effect is achieved when the sintering pressure in this invention is 3.2 MPa.

[0054] Example 4

[0055] The difference between this embodiment and Embodiment 1 is that the sintering temperature is adjusted from 800℃ to 700℃, while the rest of the preparation process is the same as in Embodiment 1, to obtain a high-entropy alloy particle-reinforced copper-based contact material.

[0056] Example 5

[0057] The difference between this embodiment and Embodiment 1 is that the sintering temperature is adjusted from 800℃ to 900℃, while the rest of the preparation process is the same as in Embodiment 1, to obtain a high-entropy alloy particle-reinforced copper-based contact material.

[0058] Comparative Example 2

[0059] The difference between this comparative example and Example 1 is that the sintering temperature was adjusted from 800℃ to 1000℃, while the rest of the preparation process was the same as in Example 1, resulting in a high-entropy alloy particle-reinforced copper-based contact material.

[0060] During the sintering process, excessively high sintering temperatures lead to rapid grain growth and an increase in defects, affecting the performance of the sample.

[0061] The performance of the materials prepared in the above embodiments was tested, and the results compared with those of Example 1 are shown in Table 2.

[0062] Table 2

[0063]

[0064]

[0065] As can be seen from the table above, adjusting the sintering temperature has a significant impact on the properties of copper-based contact materials. This is because the sintering temperature can affect the porosity, particle bonding degree, and microstructure of the material, thereby affecting its basic physical properties. According to the results in the table, the optimal technical effect can be obtained when the sintering temperature in this invention is 800℃.

[0066] Example 6

[0067] The difference between this embodiment and Embodiment 1 is that the heating rate is adjusted from 35℃ / min to 25℃ / min, while the rest of the preparation process is the same as in Embodiment 1, to obtain a high-entropy alloy particle-reinforced copper-based contact material.

[0068] Example 7

[0069] The difference between this embodiment and Embodiment 1 is that the heating rate is adjusted from 35℃ / min to 45℃ / min, while the rest of the preparation process is the same as in Embodiment 1, to obtain a high-entropy alloy particle-reinforced copper-based contact material.

[0070] The performance of the materials prepared in the above embodiments was tested, and the comparison results with those of Example 1 are shown in Table 3.

[0071] Table 3

[0072] relative density conductivity hardness Mass loss after arc erosion Example 1 90.7％ 34.2% IACS 72.3HV 0.05mg Example 6 90.1％ 32.7% IACS 71.6HV 0.08mg Example 7 90.5％ 33.4% IACS 72.1HV 0.06mg

[0073] As can be seen from the table above, adjusting the heating rate has a significant impact on the properties of copper-based contact materials. This is because the heating rate can affect the microstructure and grain growth of the material, thereby having a significant impact on density, hardness, and electrical conductivity. According to the results in the table above, the optimal technical effect can be obtained when the heating rate in this invention is 35℃ / min.

[0074] Example 8

[0075] The difference between this embodiment and Embodiment 1 is that the sintering time is adjusted from 1 hour to 0.5 hours, while the rest of the preparation process is the same as in Embodiment 1, resulting in a high-entropy alloy particle-reinforced copper-based contact material.

[0076] Example 9

[0077] The difference between this embodiment and Embodiment 1 is that the sintering time is adjusted from 1 hour to 1.5 hours, while the rest of the preparation process is the same as in Embodiment 1, to obtain a high-entropy alloy particle-reinforced copper-based contact material.

[0078] The performance of the materials prepared in the above embodiments was tested, and the results compared with those of Example 1 are shown in Table 4.

[0079] Table 4

[0080] relative density conductivity hardness Mass loss after arc erosion Example 1 90.7％ 34.2% IACS 72.3HV 0.05mg Example 8 90.3％ 33.1% IACS 71.9HV 0.07mg Example 9 90.6％ 33.8% IACS 72.1HV 0.06mg

[0081] As can be seen from the table above, adjusting the sintering time has a significant impact on the properties of copper-based contact materials. This is because the sintering time can affect the material's density, grain growth, and microstructure, thereby affecting hardness and electrical conductivity. According to the results in the table, the optimal technical effect can be obtained when the sintering time in this invention is 1 hour.

[0082] Comparative Example 3

[0083] The difference between this comparative example and Example 1 is that the reinforcing phase is adjusted to Al, Co, Ni, Cr and Fe powders, while the rest of the preparation process is the same as in Example 1, to obtain Cu-AlCoNiCrFe HEAs contact alloy.

[0084] The prepared Cu-AlCoNiCrFe HEAs contact alloy had a relative density of 90.9%, a hardness of 71.5 HV, an electrical conductivity of 33.1% IACS, and a mass loss of 0.13 mg after arc erosion. Compared with the Cu-HEAs contact alloy prepared in Example 1, the properties were similar, but the properties of the alloy decreased rapidly after arc erosion.

[0085] In summary, this invention utilizes high-energy ball milling to prepare HEAs powder with a dual-phase structure, which is then uniformly mixed with copper powder and sintered via spark plasma sintering to produce a novel Cu-HEAs contact material with a uniform and compact microstructure and HEAs particles evenly dispersed within the copper matrix. This novel Cu-HEAs contact material exhibits excellent mechanical properties, arc erosion resistance, and voltage withstand strength, providing a new approach for the preparation of copper-based contact materials.

[0086] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing a high-entropy alloy particle-reinforced copper-based contact material, characterized in that: include, (1) Preparation of high-entropy alloy powder Weigh out 2.14g Cu powder, 2.13g Co powder, 2.13g Ni powder, 1.72g Cr powder, and 1.88g Fe powder, with a particle size of 30-60μm. Remove oil from each powder, then wash with anhydrous ethanol and deionized water. Dry the powders under vacuum at 50℃. Mix the powders and place them in a ball mill jar. Add zirconia balls, controlling the ball-to-powder ratio at 15:

1. Add 1.5g of anhydrous ethanol. Set the ball mill speed to 900 rpm and the milling time to 24h. Anneal the milled powder in a tube furnace at 500℃ for 2h to obtain HEAs powder. (2) Preparation of Cu-HEAs composite powder Weigh 8.5g Cu powder and 1.5g HEAs powder. Degrease the Cu powder, then wash it with anhydrous ethanol and deionized water, and then dry the powder at 50°C under vacuum. Mix the Cu powder and HEAs powder, place them in a ball mill jar, and perform high-energy ball milling. Set the ball milling speed to 200 rpm and the ball milling time to 0.5 h to obtain Cu-HEAs composite powder. (3) Preparation of high-entropy alloy reinforced copper-based contact materials Cu-HEAs composite powder was placed in a graphite mold with a diameter of 20 mm, and then the graphite mold was placed in a plasma hot pressing sintering furnace. Vacuum was drawn and the sintering process was set. The sintering pressure was set to 3.2 MPa, the sintering temperature to 800℃, the heating rate to 35℃ / min, and the sintering time to 1 h. After the process was completed, a high-entropy alloy reinforced copper-based contact material was obtained.

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