A particulate dispersion-strengthened copper-based composite material and a method for producing the same

Abstract

The application discloses a kind of granular dispersion distribution copper-based composite material and preparation method thereof, the copper-based composite material includes Al2O3, Cr2O3, WC, Bi2O3, TeO2 and balance Cu according to mass percentage.The preparation method includes: Al, Cr and Cu are smelted and gas atomized to obtain copper aluminum chromium alloy powder, which is mixed with Cu2O powder and then subjected to heating oxidation treatment, and then subjected to crushing and reduction to obtain internal oxidation powder, then WC, Bi2O3 and TeO2 are mixed and sequentially subjected to hot isostatic pressing, hot extrusion, cold rolling, stamping and post-processing to obtain the copper-based composite material.The particles in the material are uniformly distributed, and the material is suitable for high-voltage direct-current relays, vacuum circuit breakers, load switches, industrial contactors and high-power electric vacuum tubes and other electric contact devices.

Description

Technical Field

[0001] This invention relates to the field of copper-based composite materials technology, specifically to a copper-based composite material with dispersed particle distribution and its preparation method. Background Technology

[0002] In recent years, the development of new energy vehicles and related high-voltage electrical systems has been rapid. High-voltage DC relays, as key safety devices in electric vehicles, are typically installed between the battery system and the motor controller, playing a crucial role in system start-up, fault isolation, and circuit disconnection. With the continuous expansion of the application of new energy vehicles, the demand for high-voltage DC relays is constantly increasing, and the corresponding performance requirements for contact materials are also rising. The operating voltage of new energy electric passenger vehicles is typically above 370V, and the operating voltage of buses can reach above 576V, significantly higher than the 12V or 24V operating platform of traditional fuel vehicles. Therefore, relay contact materials need to simultaneously possess good electrical and thermal conductivity, resistance to welding, high voltage resistance, and a low tendency for arc burn-off.

[0003] Currently, oxygen-free copper is commonly used as the contact material in high-voltage DC relays for new energy electric vehicles. Although oxygen-free copper has good electrical and thermal conductivity, it has a low melting point, low hardness, and high plasticity. Under high voltage, high current, and instantaneous high current impact conditions, it is prone to melting, splashing, solidification, and adhesion. This results in insufficient resistance to arc erosion, welding, and high current impact, making it difficult to meet the requirements of high-voltage DC relays for high voltage resistance, impact resistance, and stable breaking capacity.

[0004] Meanwhile, relying solely on traditional copper materials or single copper alloy systems often fails to achieve both high conductivity and high ablation resistance. When improving the performance of copper-based materials through particle composite reinforcement, issues such as uneven distribution of the reinforcing phase, insufficient wettability between the reinforcing particles and the copper matrix, difficulty in stabilizing the overall material properties, and limited consistency in batch production are also encountered. As can be seen from the technical approach presented in this disclosure, electrical contact materials must not only address the balance between conductivity and hardness but also further consider thermal stability, arc erosion resistance, weldability, and the feasibility of continuous production processes.

[0005] Therefore, there is an urgent need for a copper-based composite material with dispersed particle distribution and its preparation method, so as to further improve the service reliability of the material under high voltage, high current and frequent switching conditions while maintaining the good electrical and thermal conductivity of copper-based materials.

[0006] A search revealed a Chinese patent document disclosing a high tellurium content copper-based electrical contact material and its preparation method [Application No.: 202211534900.5, Publication No.: CN115821094B]. The method involves using copper as the matrix, copper-coated copper alloy powder as the second phase, and trace rare earth elements as the third phase. The raw materials are cold isostatically pressed into billets, and then subjected to multiple sintering, hot rolling, and aging treatments to obtain the final product. While the comparative patent achieves the goal of improving the conductivity, anti-welding performance, and arc erosion resistance of copper-based electrical contact materials, it features the use of copper as a matrix and powder metallurgy-related routes to prepare electrical contact materials, and the introduction of second and third phases to improve the overall performance of the contacts. However, this invention uses Cu-Al-Cr alloy powder, which undergoes oxidation and reduction treatment to form dispersed Al2O3 and Cr2O3 particles in situ within the copper matrix. It further combines WC, Bi2O3, and TeO2 particles, and combines hot isostatic pressing, hot extrusion, and cold rolling processes to obtain a copper-based composite material with dispersed particle distribution. This technical route of forming a nano-oxide dispersion reinforcing phase through internal oxidation and synergistic compounding with WC, Bi2O3, and TeO2 is not available in the comparative patent. At the same time, the application scenarios targeted by this invention also cover electrical contact devices with higher requirements for anti-arc erosion, anti-welding, and resistance to high current impact, such as high-voltage DC relays and vacuum circuit breakers. Summary of the Invention

[0007] To address the problems existing in the prior art, the present invention aims to provide a copper-based composite material with dispersed particle distribution and its preparation method.

[0008] A method for preparing a copper-based composite material with dispersed particle distribution, characterized by comprising the following steps: S1. Al, Cr and Cu are melted and atomized to obtain copper-aluminum-chromium alloy powder; S2. Mix the copper-aluminum-chromium alloy powder obtained in step S1 with Cu2O powder to obtain mixture 1, and heat the mixture 1 to oxidize it to obtain oxide powder 1. S3. The oxide powder 1 obtained in step S2 is crushed and reduced to obtain internally oxidized Cu-Al2O3-Cr2O3 powder. S4. Mix the Cu-Al2O3-Cr2O3 powder obtained in step S3 with WC powder, Bi2O3 powder and TeO2 powder to obtain mixture 2. S5. The mixture 2 obtained in step S4 is loaded into a pure copper sleeve, vacuumed and hot isostatically pressed to form ingot 1. S6. After removing the pure copper layer and the ends from the billet 1 obtained in step S5, hot extrusion is performed to obtain plate 1. S7. After grinding the surface of the sheet 1 obtained in step S6, cold rolling is performed to obtain sheet 2. S8. The plate 2 obtained in step S7 is stamped and post-processed to obtain the copper-based composite material with dispersed particle distribution.

[0009] Preferably, in step S1, the ingredients are prepared according to 0.46%-1.2% Al, 0.12%-0.45% Cr and the balance Cu. After melting and holding in a medium-frequency induction heating furnace for 20 minutes, the mixture is atomized with high-purity Ar gas and sieved to obtain copper-aluminum-chromium alloy powder with a particle size of (-120 mesh)-(-200 mesh).

[0010] Through the above technical solution, the present invention can obtain copper-aluminum-chromium alloy powder with relatively uniform composition distribution and suitable particle size. By limiting the ratio of Al, Cr, and Cu, and combining it with medium-frequency induction heating furnace melting, heat preservation, and high-purity Ar gas atomization treatment, it is beneficial to pre-disperse aluminum and chromium elements uniformly in the copper matrix, providing good preconditions for the formation of diffusely distributed oxide particles in the subsequent oxidation and reduction processes.

[0011] Specifically, gas atomization after melting and holding at a certain temperature for 20 minutes can stabilize the composition of the alloy liquid and reduce local segregation. Simultaneously, using high-purity Ar as the atomization medium helps reduce the impact of external impurities and unintended oxidation on powder quality during atomization. Controlling the particle size of the resulting powder to (-120 mesh)-(-200 mesh) helps to balance the powder's specific surface area, flowability, and subsequent reactivity, making it easier to achieve a more complete and uniform reaction during subsequent mixing with Cu2O and heating oxidation treatment.

[0012] In practical applications, the copper-aluminum-chromium alloy powder obtained in this step serves as the basic raw material for the entire preparation process. Its quality directly affects the subsequent internal oxidation effect, particle dispersion degree, and the overall performance of the final copper-based composite material. The aforementioned formulation and atomization methods improve the stability and repeatability of subsequent processes, laying the foundation for preparing copper-based composite materials that possess conductivity, hardness, and resistance to arc erosion.

[0013] Preferably, based on the total mass of the copper-aluminum-chromium alloy powder obtained in step S1, the amount of Cu2O powder added is 3%-8%; the particle size of the Cu2O powder is (-120 mesh)-(-200 mesh); after mixing the two in a Y-type powder mixer for 2-4 hours, the mixture is placed in a ceramic crucible with a powder thickness not exceeding 10 mm and covered with a porous stainless steel lid; subsequently, it is placed in a tunnel continuous heating furnace for heating oxidation treatment. The tunnel continuous heating furnace adopts a three-stage heating control, with the first stage temperature at 300-350℃, the second stage temperature at 450-500℃, and the third stage temperature at 600-650℃, the track running speed at 15-25 mm / min, and the total furnace time at 8-13.5 hours.

[0014] Through the above technical solution, the present invention enables relatively controllable oxidation treatment of copper-aluminum-chromium alloy powder, thereby creating conditions for the subsequent formation of a dispersed oxide reinforcing phase. By mixing copper-aluminum-chromium alloy powder with Cu2O powder of a certain proportion and particle size range, and using a tunnel continuous heating furnace with segmented heating for oxidation treatment, it is beneficial to allow oxygen to gradually diffuse in the powder system and participate in the reaction, thereby improving the uniformity and controllability of the oxidation process.

[0015] Specifically, Cu2O powder, acting as an oxygen-supplying component, provides a relatively stable oxygen source during heating after thorough mixing with copper-aluminum-chromium alloy powder. The three-stage heating control method facilitates a gradual transition from low-temperature preheating to medium- and high-temperature reaction stages, preventing rapid temperature changes that could lead to severe localized oxidation or agglomeration of the powder. Simultaneously, controlling the powder thickness to no more than 10 mm and using a porous stainless steel cap improves atmosphere exchange and heat transfer conditions during heating, resulting in a more uniform oxidation state across different powder layers.

[0016] In practical applications, this oxidation step not only affects the formation quality of alumina and chromium oxide particles in the subsequently reduced powder, but also influences the final distribution of reinforcing particles in the copper matrix. By adopting the above-mentioned powder mixing method, particle size range, and segmented oxidation process, it is beneficial to improve the uniformity of the internal oxidation precursor, thereby providing a more stable process basis for the subsequent preparation of copper-based composite materials with dispersed particle distribution.

[0017] Preferably, after mechanically crushing the oxide powder 1 obtained in step S2, the powder with a particle size of (-120 mesh) to (-200 mesh) is sieved out and then placed in a hydrogen reduction furnace for reduction treatment. The reduction treatment temperature is 600-700℃ and the reduction time is 4-8h.

[0018] Through the above technical solution, the present invention can obtain internally oxidized Cu-Al2O3-Cr2O3 powder suitable for further mixing and molding during the subsequent processing of oxidized powder. By first mechanically crushing and sieving, and then performing hydrogen reduction treatment, it is beneficial to remove unfavorable residual oxidized components in the system while retaining the required dispersed phases of alumina and chromium oxide, so that the powder has both good post-reaction microstructure and adaptability to subsequent processing.

[0019] Specifically, mechanically crushing and sieving the oxide powder first improves the particle size distribution and reduces the impact of agglomerates formed during the oxidation process on subsequent processes. Placing the sieved powder in a hydrogen reduction furnace and maintaining it at 600-700℃ for 4-8 hours helps reduce unwanted oxide components in the powder system, while simultaneously retaining the in-situ formed Al2O3 and Cr2O3 particles in the copper-based system. This not only helps restore the subsequent processing properties of the copper-based powder but also helps maintain the dispersed distribution characteristics of the reinforcing particles.

[0020] In practical applications, this reduction step serves as a crucial link between oxidation treatment and the introduction of composite reinforcing powder. Its effectiveness directly impacts the uniformity of powder mixing, the density of the molding process, and the performance stability of the final material. The combination of crushing, sieving, and reduction conditions facilitates the acquisition of a relatively stable intermediate powder, creating conditions for the subsequent addition of WC, Bi₂O₃, and TeO₂ and subsequent densification molding.

[0021] Preferably, the Cu-Al2O3-Cr2O3 powder obtained in step S3 is crushed and sieved again, and then mixed with WC powder, Bi2O3 powder and TeO2 powder in a Y-type mixer for 2-4 hours at a speed of 20 r / min. Based on the total mass of Cu-Al2O3-Cr2O3 powder obtained in step S3, the amount of WC powder added is 2%-5%, the amount of Bi2O3 powder added is 0.1%-0.5%, and the amount of TeO2 powder added is 0.1%-0.6%.

[0022] Through the above technical solution, this invention can further introduce WC, Bi2O3, and TeO2 powders onto the basis of internally oxidized Cu-Al2O3-Cr2O3 powder, thereby forming a composite powder system with synergistic effects of multiple reinforcing and modifying phases. By limiting the amount of the three added powders and controlling the mixing time and speed, it is beneficial to improve the dispersion uniformity of each component in the powder system, thus ensuring the final obtaining of a copper-based composite material with a dispersed particle distribution.

[0023] Specifically, WC particles are beneficial for improving the material's hardness, wear resistance, and resistance to arc erosion, while Bi2O3 and TeO2 are beneficial for improving the interfacial state and wetting between the reinforcing particles and the copper matrix, making it easier for the various particles to form a more stable composite structure with the copper matrix during subsequent densification and plastic processing. Limiting the addition amounts of the three additive powders within their respective ranges, and using the total mass of the powder obtained in step S3 as a benchmark for control, helps to clarify the proportions and avoids excessive component deviations that could adversely affect the material's properties.

[0024] In practical applications, the mixture 2 formed in this step is an important precursor system that determines the microstructure and overall properties of the final material. Through the above component design and powder mixing control, it is beneficial to achieve a more uniform distribution of reinforcing and modifying particles in the copper-based system, thereby achieving a better balance between electrical conductivity, thermal stability, resistance to welding, and resistance to arc erosion in the resulting copper-based composite material.

[0025] Preferably, the diameter of the pure copper sheath is Φ110mm and the thickness is 2mm; the mixture 2 obtained in step S4 is loaded into the pure copper sheath, vibrated for 2 minutes, then vacuumed and sealed, and then hot isostatic pressing is performed; the pressure of the hot isostatic pressing is 150-200MPa, the temperature is 600-750℃, and the holding time is 2-4h.

[0026] Through the above technical solution, the present invention can improve the densification of the mixed powder and provide a billet with a more uniform structure and complete structure for subsequent hot extrusion. By encapsulating the mixture 2 with a pure copper sleeve and combining it with vibration, vacuuming, sealing, and hot isostatic pressing, it is beneficial to reduce the adverse effects of internal pores and inclusions of gas on the forming quality, and improve the overall density of the billet and the stability of subsequent processing.

[0027] Specifically, the pure copper sheath not only provides physical constraint on the powder but also improves the compressive state during hot isostatic pressing (HIP), allowing the internal powder to densify more fully under high temperature and pressure conditions. Vibration for 2 minutes helps improve the compactness of the powder packing, while vacuuming and sealing reduce residual gas and oxidation risks. Controlling the HIP parameters within the range of 150-200 MPa, 600-750℃, and 2-4 h helps to ensure densification while also considering the structural stability of the powder system and its subsequent plastic processing performance.

[0028] In practical applications, this step directly relates to whether there are excessive pores, looseness, or localized unevenness within the billet, which in turn affects the quality of hot extrusion, cold rolling, and final contact forming. The aforementioned encapsulation and hot isostatic pressing processes help improve the consistency and integrity of the billet, thus providing a reliable intermediate billet for preparing copper-based composite materials with more stable performance.

[0029] Preferably, steps S6 to S8 specifically involve: removing the pure copper layer from the surface and the end of the billet 1 obtained in step S5 to a diameter of Φ90mm, then heating and hot-extending it under high-purity N2 protection to form a sheet 1 with a thickness of not less than 5mm, with a hot extrusion temperature of 600-750℃; grinding the surface of the sheet 1 and then cold-rolling it into a sheet 2 with a thickness of 1-3mm; stamping the sheet 2 into contacts on a stamping machine, and then performing surface post-treatment after holding it at 500℃ for 2 hours under N2 protection.

[0030] Through the above technical solution, the present invention can further process the billet obtained by hot isostatic pressing into contact products suitable for electrical contact applications. By sequentially performing the removal of the surface pure copper layer and ends, hot extrusion, cold rolling, stamping, and heat preservation and surface post-treatment under a protective atmosphere, it is beneficial to further improve the density and uniformity of the internal structure of the material, and enable the material to obtain suitable dimensional accuracy and service condition.

[0031] Specifically, removing the surface pure copper layer and the ends helps prevent the cladding material or edge areas from affecting the performance of subsequent products. Hot extrusion under high-purity N2 protection allows the material to form a sheet with less oxidation interference and promotes a tighter bond between the internal particles and the copper matrix. Subsequent surface polishing and cold rolling further improve the dimensional consistency and microstructure uniformity of the sheet. Stamping into contacts and holding them at 500℃ for 2 hours under N2 protection before surface post-treatment helps release some processing stress, improving the surface condition and reliability of the product.

[0032] In practical applications, this step is a critical forming stage from dense blank to terminal contact product, affecting not only the appearance and dimensions of the material, but also the particle distribution, interfacial bonding, and final service performance. Through the aforementioned continuous processing and post-processing techniques, the resulting copper-based composite materials are better suited for use in high-voltage DC relays, vacuum circuit breakers, and other electrical contact devices.

[0033] A copper-based composite material with dispersed particle distribution, comprising, by mass percentage, 0.8%-2% Al2O3, 0.15%-0.6% Cr2O3, 2%-5% WC, 0.1%-0.5% Bi2O3, 0.1%-0.6% TeO2, with the balance being Cu.

[0034] Compared with the prior art, the present invention has the following advantages:

[0035] 1. This invention employs a preparation approach combining internal oxidation and powder metallurgy to form relatively uniformly distributed reinforcing particles within a copper matrix. Subsequent densification and plastic processing further stabilize the material's microstructure. This not only helps improve problems such as ablation and adhesion that easily occur in traditional copper contacts during switching processes, but also achieves a better balance between conductivity, thermal stability, and durability, making it more suitable for electrical contact applications with significant load variations.

[0036] 2. This invention further introduces multiple functional components into the oxide particles, enabling different particles to exert synergistic effects within the copper matrix. This improves the bonding between the particles and the matrix and enhances the overall performance of the material under heating and arc conditions. Compared to single copper materials or ordinary alloy materials, this approach places greater emphasis on the construction of the material's microstructure and the continuous connection of the processing steps, thus making it easier to balance actual processing needs with the requirements of subsequent device use. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the workflow of the present invention;

[0038] Figure 2 This is a transmission electron microscope (TEM) image of the copper-based composite material of this invention. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] Equivalent substitutions, conventional adjustments, and reasonable improvements made by those skilled in the art based on the disclosure of this invention should all fall within the protection scope of this invention.

[0041] This invention provides a copper-based composite material with dispersed particle distribution and its preparation method. The method employs a process route combining internal oxidation and powder metallurgy. Through Cu-Al-Cr alloy powder atomization, oxidation, reduction, and mixing, combined with hot isostatic pressing, hot extrusion, cold rolling, and post-treatment, dispersed reinforcing particles are formed within a copper matrix to obtain the copper-based composite material. The copper-based composite material comprises Al2O3, Cr2O3, WC, Bi2O3, TeO2, and Cu. The process flow of this invention is as follows: Figure 1 As shown.

[0042] In the atomized powder preparation process, Al, Cr, and Cu are melted and atomized to obtain copper-aluminum-chromium alloy powder. By controlling the distribution of Al and Cr in the copper-based powder, a precursor basis is provided for the formation of internal oxidation products in subsequent oxidation treatment. The atomized powder can be melted in a ratio of 0.46-1.2 wt% Al, 0.12-0.45 wt% Cr, and the balance Cu, and then atomized with high-purity Ar gas and sieved to obtain copper-aluminum-chromium alloy powder with the corresponding particle size range.

[0043] In the powder oxidation process, the copper-aluminum-chromium alloy powder is mixed with Cu2O powder and then subjected to heating oxidation. By setting three heating temperature zones and controlling the powder thickness, track running speed, and furnace residence time, the oxidation process is carried out under continuous heating conditions. After this step, the powder system forms the oxidized state required for subsequent reduction treatment.

[0044] In the powder reduction process, the oxidized powder is mechanically crushed and sieved, and then placed in a hydrogen reduction furnace for further treatment to obtain internally oxidized Cu-Al2O3-Cr2O3 powder. After this step, dispersed Al2O3 and Cr2O3 particles are formed in the powder system, providing the base powder for the subsequent introduction of composite reinforcing particles.

[0045] During the powder mixing process, the Cu-Al2O3-Cr2O3 powder is uniformly mixed with WC powder, Bi2O3 powder, and TeO2 powder to form a composite powder system. The mixed powder is then loaded into a pure copper sheath, vibrated, vacuumed, and sealed before hot isostatic pressing (HIP) to improve the density of the blank. After HIP, the pure copper layer on the sheath surface and the ends are removed, followed by hot extrusion, cold rolling, and stamping. Finally, post-processing yields the copper-based composite material product.

[0046] Through the above process route, the oxide particles formed by internal oxidation and the subsequently added WC, Bi2O3 and TeO2 particles can form a relatively uniform composite distribution in the copper matrix, thereby obtaining the copper-based composite material with the particles dispersed.

[0047] Example 1: High-aluminum, low-chromium precursor powder example A method for preparing a copper-based composite material with dispersed particle distribution includes the following steps: Preparation of atomized powder: Pure copper, pure aluminum and pure chromium were melted in a medium frequency induction heating furnace according to the alloy ratio of Cu-1.2wt%Al-0.12wt%Cr. The raw materials were heated to fully melt and kept at the temperature for 20 minutes. Then, high-purity Ar gas was used for atomization. After sieving, copper-aluminum-chromium alloy powder was obtained with a particle size of (-120 mesh).

[0048] Powder oxidation treatment: 10 kg of the prepared copper-aluminum-chromium alloy powder and 800 g of Cu2O powder with a particle size of (-120 mesh) were mixed in a Y-type powder mixer for 2 hours. The mixed powder was then placed in a ceramic crucible, with a powder thickness not exceeding 10 mm. After covering with a porous stainless steel lid, the crucible was placed in a tunnel continuous heating furnace and subjected to heating oxidation treatment via a continuous track. The tunnel continuous heating furnace implemented three-stage heating control, with the first stage temperature at 350℃, the second stage temperature at 500℃, and the third stage temperature at 650℃. The track running speed was 15 mm / min, and the total time in the tunnel furnace was 13.5 hours.

[0049] Powder reduction treatment: The oxidized powder is mechanically crushed by a crusher and then screened to obtain powder with a particle size of (-120 mesh). The powder is then placed in a hydrogen reduction furnace for reduction treatment to obtain internally oxidized Cu-Al2O3-Cr2O3 powder. The reduction temperature is 700℃ and the time is 4h.

[0050] Powder mixing: The reduced powder is crushed and sieved again, and 225g of WC powder, 56g of Bi2O3 powder and 67g of TeO2 powder are added. The powder is then mixed evenly in a Y-type powder mixer for 2 hours at a speed of 20r / min.

[0051] Hot isostatic pressing: The mixed powder is loaded into a pure copper sleeve with a diameter of Φ110mm and an air tube. The thickness of the pure copper sleeve is 2mm. After vibration for 2 minutes, vacuuming is started. Then the sleeve is sealed and hot isostatic pressing is performed on a hot isostatic press at a pressure of 200MPa, a temperature of 750℃, and a holding time of 2h.

[0052] Hot extrusion: The billet, after being hot isostatically pressed and cooled, is completely machined to a diameter of Φ90mm. It is then heated under high-purity N2 protection and hot extruded into a sheet with a thickness of 5mm at an extrusion temperature of 750℃.

[0053] Cold rolling: After the hot-extruded sheet is surface-polished, it is cold-rolled into a 3mm sheet.

[0054] Stamping and post-treatment: Cold-rolled sheet metal is stamped on a stamping machine to obtain contacts. These contacts are then held at 500℃ for 2 hours under N2 protection, followed by surface post-treatment to obtain a copper-based composite material with dispersed particle distribution. The copper-based composite material prepared according to the above steps contains 2wt% Al2O3, 0.15wt% Cr2O3, 2wt% WC, 0.5% Bi2O3, 0.6% TeO2, and the remainder is Cu. The material has an electrical conductivity of 51% IACS and a Brinell hardness of HB 118.

[0055] Example 2: Low-aluminum, high-chromium precursor powder example A method for preparing a copper-based composite material with dispersed particle distribution includes the following steps: Preparation of atomized powder: Pure copper, pure aluminum and pure chromium were melted in a medium frequency induction heating furnace according to the alloy ratio of Cu-0.46wt%Al-0.45wt%Cr. The materials were heated to fully melt and held at the temperature for 20 minutes. Then Ar gas was used for atomization. After sieving, copper-aluminum-chromium alloy powder was obtained with a particle size of (-200 mesh).

[0056] Powder oxidation treatment: 10 kg of the prepared copper-aluminum alloy powder and 300 g of Cu2O powder with a particle size of (-200 mesh) were mixed in a Y-type powder mixer for 4 hours at a speed of 20 r / min. The mixed powder was then placed in a ceramic crucible, with a powder thickness not exceeding 10 mm. After covering with a porous stainless steel lid, the crucible was placed in a tunnel continuous heating furnace and subjected to oxidation treatment via a continuous track. The tunnel continuous heating furnace implemented three-stage heating control, with the first stage temperature at 300℃, the second stage temperature at 450℃, and the third stage temperature at 600℃. The track running speed was 25 mm / min, and the total time in the tunnel furnace was 8 hours.

[0057] Powder reduction treatment: The oxidized powder is mechanically crushed by a crusher and then screened to obtain powder with a particle size of (-200 mesh). The powder is then placed in a hydrogen reduction furnace for reduction treatment to obtain internally oxidized Cu-Al2O3-Cr2O3 powder. The reduction temperature is 600℃ and the time is 8h.

[0058] Powder mixing: The reduced powder is crushed and sieved again, and 548g of WC powder, 11g of Bi2O3 powder and 11g of TeO2 powder are added. The powder is mixed evenly in a Y-type powder mixer for 4 hours at a speed of 20r / min.

[0059] Hot isostatic pressing: The mixed powder is loaded into a pure copper sleeve with a diameter of Φ110mm and an air tube. The thickness of the pure copper sleeve is 2mm. After vibration for 2 minutes, vacuuming is started. Then the sleeve is sealed and hot isostatic pressing is performed on a hot isostatic press at a pressure of 150MPa, a temperature of 600℃, and a holding time of 4h.

[0060] Hot extrusion: The billet, after being hot isostatically pressed and cooled, is completely machined to Φ90mm on the surface and ends, heated under high-purity N2 protection, and hot extruded into 5mm sheet at an extrusion temperature of 600℃.

[0061] Cold rolling: After the hot-extruded sheet is surface-polished, it is cold-rolled into a 1mm sheet.

[0062] Stamping and post-treatment: Cold-rolled sheet metal is stamped on a stamping machine to obtain contacts. These contacts are then held at 500℃ for 2 hours under N2 protection, followed by surface post-treatment to obtain a copper-based composite material with dispersed particle distribution. The copper-based composite material prepared according to the above steps contains 0.8wt% Al2O3, 0.6wt% Cr2O3, 5wt% WC, 0.1% Bi2O3, 0.1% TeO2, with the remainder being Cu. The material has an electrical conductivity of 62% IACS and a Brinell hardness of HB 102.

[0063] Example 3: Precursor Powder with Medium Aluminum-Chromium Ratio A method for preparing a copper-based composite material with dispersed particle distribution includes the following steps: Preparation of atomized powder: Pure copper, pure aluminum and pure chromium were melted in a medium frequency induction heating furnace according to the alloy ratio of Cu-1.0wt%Al-0.25wt%Cr. The materials were heated to fully melt and held at the temperature for 20 minutes. Then Ar gas was used for atomization. After sieving, copper-aluminum-chromium alloy powder was obtained with a particle size of (-180 mesh).

[0064] Powder oxidation treatment: 10 kg of the prepared copper-aluminum alloy powder and 500 g of Cu2O powder with a particle size of (-180 mesh) were mixed in a Y-type powder mixer for 3 hours at a speed of 20 r / min. The mixed powder was then placed in a ceramic crucible, with a powder thickness not exceeding 10 mm. After covering with a porous stainless steel lid, the crucible was placed in a tunnel continuous heating furnace and subjected to oxidation treatment via a continuous track. The tunnel continuous heating furnace implemented three-stage heating control, with the first stage temperature at 320℃, the second stage temperature at 480℃, and the third stage temperature at 620℃. The track running speed was 20 mm / min, and the total time in the tunnel furnace was 10 hours.

[0065] Powder reduction treatment: The oxidized powder is mechanically crushed by a crusher and then screened to obtain powder with a particle size of (-160 mesh). The powder is then placed in a hydrogen reduction furnace for reduction treatment to obtain internally oxidized Cu-Al2O3-Cr2O3 powder. The reduction temperature is 640℃ and the time is 6h.

[0066] Powder mixing: The reduced powder is crushed and sieved again, and 444g of WC powder, 35g of Bi2O3 powder and 35g of TeO2 powder are added. The powder is mixed evenly in a Y-type powder mixer for 3 hours at a speed of 20r / min.

[0067] Hot isostatic pressing: The mixed powder is loaded into a pure copper sleeve with a diameter of Φ110mm and an air tube. The thickness of the pure copper sleeve is 2mm. After vibration for 2 minutes, vacuuming is started. Then the sleeve is sealed and hot isostatic pressing is performed on a hot isostatic press at a pressure of 180MPa, a temperature of 675℃, and a holding time of 3h.

[0068] Hot extrusion: The billet, after being hot isostatically pressed and cooled, is completely machined to Φ90mm on the surface and ends, heated under high-purity N2 protection, and hot extruded into 5mm sheet at an extrusion temperature of 675℃.

[0069] Cold rolling: After the hot-extruded sheet is surface-polished, it is cold-rolled into a 2mm sheet.

[0070] Stamping and post-treatment: Cold-rolled sheet metal is stamped on a stamping machine to obtain contacts. These contacts are then held at 500℃ for 2 hours under N2 protection, followed by surface post-treatment to obtain a copper-based composite material with dispersed particle distribution. The copper-based composite material prepared according to the above steps contains 1.71wt% Al2O3, 0.33wt% Cr2O3, 4wt% WC, 0.32% Bi2O3, 0.32% TeO2, with the remainder being Cu. The material has an electrical conductivity of 56% IACS and a Brinell hardness of HB 108.

[0071] As attached Figure 2 As shown in the transmission electron microscope image of the copper-based composite material with dispersed particle distribution obtained in the example, black particles are visible distributed in the copper matrix, including Al2O3 particles and Cr2O3 particles formed by internal oxidation. The oxide particles are in a dispersed and uniformly distributed state, and the micron-sized particles are mainly distributed between the atomized particles.

[0072] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a copper-based composite material with dispersed particle distribution, characterized in that, Includes the following steps: S1. Al, Cr and Cu are melted and atomized to obtain copper-aluminum-chromium alloy powder; S2. Mix the copper-aluminum-chromium alloy powder obtained in step S1 with Cu2O powder to obtain mixture 1, and heat the mixture 1 to oxidize it to obtain oxide powder 1. S3. The oxide powder 1 obtained in step S2 is crushed and reduced to obtain internally oxidized Cu-Al2O3-Cr2O3 powder. S4. Mix the Cu-Al2O3-Cr2O3 powder obtained in step S3 with WC powder, Bi2O3 powder and TeO2 powder to obtain mixture 2. S5. The mixture 2 obtained in step S4 is loaded into a pure copper sleeve, vacuumed and hot isostatically pressed to form ingot 1. S6. After removing the pure copper layer and the ends from the billet 1 obtained in step S5, hot extrusion is performed to obtain plate 1. S7. After grinding the surface of the sheet 1 obtained in step S6, cold rolling is performed to obtain sheet 2. S8. The plate 2 obtained in step S7 is stamped and post-processed to obtain the copper-based composite material with dispersed particle distribution.

2. The preparation method according to claim 1, characterized in that, In step S1, the ingredients are prepared according to 0.46%-1.2% Al, 0.12%-0.45% Cr and the balance Cu. After melting and holding in a medium frequency induction heating furnace for 20 minutes, high-purity Ar gas is used for atomization and sieving to obtain copper-aluminum-chromium alloy powder with a particle size of (-120 mesh)-(-200 mesh).

3. The preparation method according to claim 1, characterized in that, In step S2, based on the total mass of the copper-aluminum-chromium alloy powder obtained in step S1, the amount of Cu2O powder added is 3%-8%; the particle size of the Cu2O powder is (-120 mesh)-(-200 mesh); after mixing the two in a Y-type powder mixer for 2-4 hours, the mixture is placed in a ceramic crucible with a powder thickness not exceeding 10 mm and covered with a porous stainless steel lid; subsequently, it is placed in a tunnel continuous heating furnace for heating oxidation treatment. The tunnel continuous heating furnace adopts a three-stage heating control, with the first stage temperature at 300-350℃, the second stage temperature at 450-500℃, and the third stage temperature at 600-650℃, the track running speed at 15-25 mm / min, and the total furnace time at 8-13.5 hours.

4. The preparation method according to claim 1, characterized in that, In step S3, the oxide powder 1 obtained in step S2 is mechanically crushed and screened to obtain powder with a particle size of (-120 mesh) to (-200 mesh). The powder is then placed in a hydrogen reduction furnace for reduction treatment. The reduction treatment temperature is 600-700℃ and the reduction time is 4-8h.

5. The preparation method according to claim 1, characterized in that, In step S4, the Cu-Al2O3-Cr2O3 powder obtained in step S3 is crushed and sieved again, and then mixed with WC powder, Bi2O3 powder and TeO2 powder in a Y-type mixer for 2-4 hours at a speed of 20 r / min. Based on the total mass of Cu-Al2O3-Cr2O3 powder obtained in step S3, the amount of WC powder added is 2%-5%, the amount of Bi2O3 powder added is 0.1%-0.5%, and the amount of TeO2 powder added is 0.1%-0.6%.

6. The preparation method according to claim 1, characterized in that, In step S5, the diameter of the pure copper sheath is Φ110mm and the thickness is 2mm; the mixture 2 obtained in step S4 is loaded into the pure copper sheath, vibrated for 2 minutes, then vacuumed and sealed, and then hot isostatic pressing is performed; the pressure of the hot isostatic pressing is 150-200MPa, the temperature is 600-750℃, and the holding time is 2-4h.

7. The preparation method according to claim 1, characterized in that, Steps S6 to S8 are specifically as follows: After removing the pure copper layer on the surface and the end of the billet 1 obtained in step S5 to a diameter of Φ90mm, it is heated and hot-extruded into a sheet 1 with a thickness of not less than 5mm under high-purity N2 protection, and the hot extrusion temperature is 600-750℃; the surface of the sheet 1 is polished and then cold-rolled into a sheet 2 with a thickness of 1-3mm; the sheet 2 is stamped into contacts on a stamping machine, and after being kept at 500℃ for 2h under N2 protection, surface post-treatment is performed.

8. A copper-based composite material with dispersed particle distribution, characterized in that, By mass percentage, it includes 0.8%-2% Al2O3, 0.15%-0.6% Cr2O3, 2%-5% WC, 0.1%-0.5% Bi2O3, 0.1%-0.6% TeO2, and the balance is Cu.

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