Preparation furnace and preparation method of high-entropy alloy powder

Abstract

The invention relates to the technical field of alloy powder preparation, and discloses a high-entropy alloy powder preparation furnace and method. The high-entropy alloy powder preparation furnace comprises a raw material treatment and vacuum melting unit, a dual-mode atomization unit, a radio frequency plasma spheroidizing and heat treatment unit and a collecting unit. The raw material processing and vacuum melting unit is used for completing vacuum melting of metal raw materials and providing metal melt. The dual-mode atomization unit comprises a gas atomization module and a laser irradiation atomization module, when submicron or nanoscale powder needs to be produced, the gas atomization module and the laser irradiation atomization module are started to operate, and high-energy nanosecond pulse laser is used for scanning a metal liquid flow or a target material, so that metal is vaporized to form superfine powder; when micron-sized powder needs to be produced, the gas atomization module is independently started; the radio frequency plasma spheroidizing and heat treatment unit is used for receiving the powder output by the dual-mode atomization unit and performing spheroidizing and purification treatment; and the collecting unit is used for hermetically collecting the spheroidized and purified powder.

Description

Technical Field

[0001] This invention belongs to the field of alloy powder preparation technology, specifically relating to a furnace and method for preparing high-entropy alloy powder. Background Technology

[0002] High-entropy alloys are composed of five or more main metallic elements. Due to their unique high-entropy effect, lattice distortion effect and hysteresis diffusion effect, they exhibit excellent mechanical properties, corrosion resistance and high-temperature stability, and have broad application prospects in aerospace, new energy catalysts, nuclear energy and other fields.

[0003] Currently, the preparation of high-entropy alloy powders mainly faces the following challenges: Difficulty in homogenizing elements: Traditional smelting methods rely on high temperature and long-term diffusion, which leads to poor compatibility of different metal elements and easy segregation.

[0004] There is a contradiction between powder sphericity and purity. While mainstream gas atomization methods can produce spherical powders, refractory metals are prone to oxidation and have high oxygen content. Radio frequency plasma spheroidization can effectively purify and spheroidize powders, but it usually requires pre-alloying or pre-powdering, resulting in a long process.

[0005] Bottlenecks in the preparation of sub-nanometer and nano-scale powders: Traditional methods struggle to achieve precise control of particle size under mild conditions, and the preparation of sub-nanometer-scale high-entropy alloy catalyst powders is particularly challenging.

[0006] Nanosecond pulsed lasers can heat material surfaces to over 2000 degrees Celsius in an extremely short time and cool them at a rate exceeding one billion degrees per second, achieving a thermal cycle of instantaneous ultra-high temperature and rapid quenching. This process not only forces the rapid mutual solubility of various metallic elements at the atomic scale and suppresses segregation, but also precisely controls particle nanostructuring, and has successfully prepared various sub-nanometer-scale high-entropy alloys in the laboratory. However, this technology is currently mostly limited to gram-level preparation in the laboratory, and there are no precedents for deep integration with industrial powder preparation equipment.

[0007] Therefore, the present invention aims to design a furnace for preparing high-entropy alloy powder, which organically integrates laser irradiation ultrafast synthesis technology with mature vacuum melting, gas atomization and plasma spheroidization technologies. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention proposes a furnace for preparing high-entropy alloy powder, comprising: a raw material processing and vacuum melting unit, a dual-mode atomization unit, a radio frequency plasma spheroidization and heat treatment unit, and a collection unit; The raw material processing and vacuum melting unit is used to complete the vacuum melting of metal raw materials and provide molten metal. The dual-mode atomization unit includes a gas atomization module and a laser irradiation atomization module. When it is necessary to produce submicron or nano-sized powders, the gas atomization module and the laser irradiation atomization module are used alternately to scan the metal liquid flow or target material with a high-energy nanosecond pulsed laser, so that the metal is vaporized to form submicron or nano-sized powders. When it is necessary to produce micron-sized powders, the gas atomization module is used alone. The radio frequency plasma spheroidizing and heat treatment unit is used to receive the powder output from the dual-mode atomization unit and perform spheroidizing and purification treatment. The collection unit is used to collect the powder after spheroidization and purification in an inert atmosphere.

[0009] Furthermore, the raw material processing and vacuum melting unit includes a vacuum feeding hopper, a weighing mixer, and a vacuum induction melting furnace; the vacuum feeding hopper is used to quantitatively receive and transport metal raw materials in a vacuum environment; the weighing mixer is used to weigh and mix the metal raw materials; the vacuum induction melting furnace is used to melt the mixed raw materials into a molten metal and is equipped with a rapid pouring mechanism.

[0010] Furthermore, the vacuum induction melting furnace includes a vacuum system, an electromagnetic stirring device, an induction heating coil, and a double-layer water-cooled jacketed furnace body. The rapid pouring mechanism is installed on the furnace cover and is used to rapidly pour the molten metal into the dual-mode atomization unit under vacuum or inert atmosphere.

[0011] Furthermore, the gas atomization module includes a tightly coupled annular nozzle and a high-pressure gas channel that cooperates with it; the laser irradiation atomization module includes a high-energy nanosecond pulse laser and an optical scanning galvanometer. The laser irradiation atomization module uses a high-energy nanosecond pulse laser, and the optical scanning galvanometer is used to guide the laser beam and quickly scan it onto the surface of the molten metal or alloy target, so that the metal is instantly vaporized to form fine droplets.

[0012] Furthermore, the radio frequency plasma spheroidizing and heat treatment unit includes: a radio frequency plasma torch for generating high-temperature plasma to instantly melt the powder; a spheroidizing furnace body surrounding the radio frequency plasma torch, internally divided into a spheroidizing region and a high-temperature region; a degassing and purification device integrated into the high-temperature region of the spheroidizing furnace body for evaporating impurities using high-temperature plasma to purify the powder; and a water-cooling tank located at the outlet end of the spheroidizing furnace body for rapidly cooling and solidifying the spherical powder.

[0013] Furthermore, the collection unit also includes: a multi-stage cyclone separator for centrifugally classifying the produced micron-sized powder to obtain coarse and fine particles, and returning the separated coarse particles to the radio frequency plasma spheroidization and heat treatment unit; a vibrating sieve equipped with a screen and a double-helix pusher plate for vibrating sieve of fine powder particles; and an inert atmosphere packaging box for collecting and packaging the finished powder under an inert atmosphere.

[0014] This invention also proposes a method for preparing high-entropy alloy powder, which uses the aforementioned preparation furnace and includes the following steps: Metal raw materials are weighed and mixed in a vacuum environment, and then heated and melted into a metal melt in a vacuum induction melting furnace; Under the protection of an inert atmosphere, the molten metal is transported to a dual-mode atomization unit. When it is necessary to produce submicron or nano-sized powder, the gas atomization module and the laser irradiation atomization module are alternately activated. A high-energy nanosecond pulsed laser is used to scan the molten metal flow or the target material, causing the metal to vaporize and form submicron or nano-sized powder. When it is necessary to produce micron-sized powder, the gas atomization module is activated alone. Inert gas is used to break the molten metal into micron-sized powder through a tightly coupled annular nozzle. The generated powder is transported to the radio frequency plasma spheroidization and heat treatment unit, where the powder is instantly melted, spheroidized, densified and degassed and purified. Then it is rapidly cooled and solidified into spherical powder through a water cooling tank. The spherical powder was collected in a sealed manner under an inert atmosphere.

[0015] Furthermore, the laser irradiation atomization module employs a high-energy nanosecond pulsed laser to scan the metal liquid flow or target material with a laser beam of wavelength 1064nm, pulse width 3-10ns, and repetition frequency 10-100kHz, causing the metal to vaporize and form submicron or nanoscale powder.

[0016] Furthermore, the produced micron-sized powder is centrifuged and classified to obtain coarse and fine particles, and the separated coarse particles are returned to the radio frequency plasma spheroidization and heat treatment unit; the fine particles are vibrated and sieved; finally, the finished powder is collected and packaged in an inert atmosphere through an inert atmosphere packaging box.

[0017] Compared with the prior art, the present invention has the following significant advantages: The preparation furnace is compatible with both micron-level atomization and nano-level laser synthesis routes, allowing for rapid switching according to product requirements and high equipment utilization. The ultrafast laser process suppresses elemental segregation, and combined with plasma spheroidization, ensures atomic-level mixing of multiple principal elements.

[0018] Plasma refining can effectively reduce the oxygen content of powder to below 200 ppm and the hydrogen content to below 15 ppm. Precise control is possible from the conventional 15-63 μm to submicron and even subnanometer levels.

[0019] The laser synthesis path has an extremely short reaction time, resulting in significantly lower total energy consumption compared to high-temperature smelting throughout the entire process. The preparation furnace is also compatible with recycling waste materials, reducing raw material costs. The entire process is completed in a vacuum or protective atmosphere, integrating online monitoring and intelligent control, ensuring stable product quality and suitability for continuous, large-scale production. Attached Figure Description

[0020] Figure 1 This is a front view of the high-entropy alloy powder preparation furnace of the present invention. Figure 2 This is a flowchart of the high-entropy alloy powder preparation method of the present invention; Figure 3 The high-entropy alloy powder prepared in Example 2 of this invention; Figure 4 This refers to (FeCoNi) in Embodiment 3 of the present invention. 86 SEM image of micron-sized spherical powder of Al7Ti7 high-entropy alloy. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in further detail below with reference to the accompanying drawings and specific embodiments, but the implementation and protection scope of this invention are not limited thereto.

[0022] Example 1: As Figure 1 As shown, the high-entropy alloy powder preparation furnace of the present invention includes a raw material processing and vacuum melting unit 1, a dual-mode atomization unit 2, a radio frequency plasma spheroidization and heat treatment unit 3, and a collection unit 4. Each unit is connected in sequence through vacuum pipes and gas lock valves to form a powder preparation system, which can ensure that raw materials and intermediate products flow in a vacuum or inert atmosphere environment, reducing oxidation pollution.

[0023] I. Raw Material Processing and Vacuum Melting Unit This unit, serving as the starting point for powder preparation, mainly comprises a vacuum feeding hopper, a weighing mixer, and a vacuum induction melting furnace. These structures are sequentially connected according to the raw material processing flow. The vacuum feeding hopper is the first structure where raw materials enter the raw material processing and vacuum melting unit. It receives raw materials such as metal blocks, metal powders, or pre-placed targets, and features excellent vacuum sealing, enabling quantitative feeding in a vacuum environment. After feeding, the raw materials are directly conveyed to the weighing mixer. The weighing mixer receives the raw materials from the vacuum feeding hopper and ensures the accuracy of the alloy composition ratio in subsequent melting by precisely weighing different metal components. The mixed raw materials are then conveyed to the vacuum induction melting furnace. The vacuum induction melting furnace is the core structure of the raw material processing and vacuum melting unit. It receives the mixed raw materials from the weighing mixer and integrates a vacuum system, an electromagnetic stirring device, and an induction heating coil. It is also equipped with a rapid tilting and pouring mechanism located on the furnace lid. The furnace body adopts a double-layer water-cooled jacket design and has a polished inner wall. This structure achieves non-contact heating of raw materials through medium-frequency induction technology, with a maximum operating temperature of 2000℃. During the heating process, an electromagnetic stirring device ensures uniform melt. After melting, the molten metal is quickly poured into the subsequent dual-mode atomization unit under vacuum or inert atmosphere through a rapid pouring and casting mechanism, reducing the contact time between the metal and air to prevent oxidation.

[0024] II. Dual-mode atomization unit This unit is the core of the system's spraying process, responsible for cutting the molten metal delivered by the preceding raw material processing and vacuum melting units into fine droplets. It mainly consists of two parallel atomization structures: a gas atomization module and a laser irradiation atomization module. Both modules are connected to the rapid pouring and casting mechanism or the raw material output end of the raw material processing and vacuum melting units, and can be selected to work individually or in tandem according to the preparation requirements.

[0025] The gas atomization module comprises two working structures: a tightly coupled annular slit nozzle and a high-pressure gas channel. The tightly coupled annular slit nozzle, located at the bottom of the atomization chamber of the gas atomization module, is designed as an annular slit structure to directly receive the molten metal flowing out from the raw material processing and vacuum melting units, forming an annular liquid film after the molten metal flows out. The high-pressure gas channel works in conjunction with the tightly coupled annular slit nozzle to introduce high-purity argon or nitrogen gas at 2-8 MPa. The gas jet directly impacts the annular liquid film through this channel, using turbulent shear force to break the liquid film into micron-sized powder. Under this pressure condition, the gas velocity can reach over 540 m / s, which can significantly reduce the surface tension of the molten metal and achieve efficient atomization.

[0026] The laser irradiation atomization module comprises two core structures: a high-energy nanosecond pulsed laser and an optical scanning galvanometer. These two structures are connected via an optical path. The high-energy nanosecond pulsed laser generates a laser beam with a wavelength of 1064 nm, a pulse width of 3-10 ns, a repetition frequency of 10-100 kHz, and a peak power of several MW. After being conducted by the optical scanning galvanometer, the laser beam directly irradiates the molten metal flow from the melting unit or a pre-placed alloy target. The optical scanning galvanometer can rapidly scan the laser beam to ensure that the laser energy uniformly covers the surface of the molten metal flow. After the laser energy is absorbed by the metal, it instantly heats up and generates a plasmonic photothermal effect, causing the metal to vaporize instantly and violently collide with the molten metal to form fine droplets. This module can prepare submicron or nanoscale powders, and the atomized particles are finer and more uniform.

[0027] Specifically, the gas atomization module and the laser irradiation atomization module can be selected to work individually or in combination according to the preparation requirements. When it is necessary to produce submicron or nano-sized powders, the gas atomization module and the laser irradiation atomization module are used alternately to scan the metal liquid flow or target material with a high-energy nanosecond pulse laser, so that the metal is vaporized to form submicron or nano-sized powders. When it is necessary to produce micron-sized powders, the gas atomization module is used alone.

[0028] III. Radio Frequency Plasma Spheroidization and Heat Treatment Unit This unit receives powder from the dual-mode atomization unit and primarily achieves powder densification, spheroidization, degassing purification, and cooling solidification. The core comprises three structures: a radio frequency plasma torch, a spheroidizing furnace, and a degassing purification device. These structures are interconnected according to the powder processing flow and integrated within the same inert atmosphere. The radio frequency plasma torch, with a power range of 30-50kW, is the core heating structure, directly receiving powder from the dual-mode atomization unit and instantly melting the coarse powder by generating high-temperature plasma. The spheroidizing furnace surrounds the radio frequency plasma torch and is internally divided into a spheroidizing zone and a high-temperature zone. The molten powder undergoes spheroidization and densification in the spheroidizing zone. A water-cooling tank is located at the outlet of the spheroidizing furnace, allowing the densified molten metal droplets to rapidly cool and solidify, ultimately forming spherical powder. The degassing purification device is integrated into the high-temperature zone within the spheroidizing furnace. During spheroidization, the high-temperature plasma evaporates impurities such as lead and sulfur from the powder, achieving powder purification. The entire unit employs a radiant furnace structure and uses radio frequency induction heating to avoid arc contamination caused by electrode contact.

[0029] IV. Collection Unit This unit, as the final stage of powder preparation, is responsible for classifying, sorting, and sealing the spheroidized powder.

[0030] The collection unit also includes three core structures: a multi-stage cyclone separator, a vibrating screen, and an inert atmosphere packaging box. It also integrates an online particle size analyzer for centrifugal classification of the produced micron-sized powder to obtain coarse and fine particles. The structures are connected sequentially according to the sorting-collection process. The multi-stage cyclone separator directly receives the powder output from the radio frequency plasma spheroidization and heat treatment unit. It employs a multi-stage series cyclone structure, using centrifugal force to separate large and fine powder particles in the airflow. The separated coarse particles are discharged directly through the return channel and returned to the spheroidization unit for reprocessing, while the fine particles are conveyed to a vibrating screen. The vibrating screen receives the fine powder from the multi-stage cyclone separator and has multiple screens with adjustable mesh sizes. A rotating shaft is mounted on the screen plate, and a double-helix pusher plate is fixedly connected to the outside of the shaft. The double-helix pusher plate slides in contact with the screen plate, achieving secondary sieving of the powder through vibration. Simultaneously, the double-helix pusher plate pushes the powder outward, avoiding the disorderly diffusion of powder in traditional vibrating sieving. The inert atmosphere packaging box receives the qualified powder after screening by the vibrating screen and is used for the final collection of metal powder. This packaging box has vacuuming and nitrogen or argon filling functions, ensuring that the powder is in an inert gas protective environment during packaging, preventing oxidation and moisture absorption.

[0031] Example 2: A method for preparing high-entropy alloy powder, implemented using the above-mentioned preparation furnace, as follows... Figure 2 As shown, it includes the following steps: Metal raw materials are weighed and mixed in a vacuum environment, and then heated and melted into a metal melt in a vacuum induction melting furnace; Under an inert atmosphere, the molten metal is transported to the dual-mode atomization unit through a guide tube. When it is necessary to produce submicron or nanoscale powder, the gas atomization module and the laser irradiation atomization module are alternately activated. A high-energy nanosecond pulsed laser is used to scan the molten metal or target material, causing the metal to vaporize and form ultrafine powder. When it is necessary to produce micron-scale powder, the gas atomization module is activated alone. An inert gas is used to break the molten metal into micron-scale powder through a tightly coupled annular nozzle. The laser irradiation atomization module uses a high-energy nanosecond pulsed laser with a wavelength of 1064nm, a pulse width of 3-10ns, and a repetition frequency of 10-100kHz to scan the molten metal or alloy target material, causing the metal to vaporize and form submicron or nanoscale powder.

[0032] The powder is fed to the radio frequency plasma spheroidization and heat treatment unit, where it is instantly melted, spheroidized, densified and degassed and purified. Then it is rapidly cooled and solidified into spherical powder through a water cooling tank. When the gas atomization module is used alone to produce micron-sized powder, the spherical powder is sequentially subjected to cyclone separation and classification followed by vibratory sieving to obtain finished powder within the target particle size range, which is then sealed and collected under an inert atmosphere. The cyclone separation and classification returns coarse particles larger than 53 μm for plasma spheroidization treatment, and the vibratory sieving process filters the powder to the target particle size range of 15-53 μm.

[0033] Specifically, when producing submicron or nanoscale powders, the system alternately operates the gas atomization module and the laser irradiation atomization module. First, the molten metal from the raw material processing and vacuum melting unit is introduced into the atomization chamber of the gas atomization module. Initially, the gas atomization module operates briefly, using a high-pressure inert gas jet to initially break up the molten metal flow, forming droplets or fine streams with a certain degree of dispersion. Subsequently, the gas atomization module pauses, and the laser irradiation atomization module starts. A laser beam generated by a high-energy nanosecond pulsed laser, guided by an optical scanning galvanometer, rapidly scans and acts on the molten metal flow or a pre-placed alloy target surface. Through the plasmon photothermal effect, the metal is instantaneously and locally vaporized, generating metal vapor that violently collides with the surrounding melt, thus forming submicron or nanoscale ultrafine droplets. In this path, the system focuses on using the ultrafast process of laser to synthesize ultrafine powders; gas atomization mainly plays an auxiliary role in dispersion and pretreatment. The two processes alternate rather than operate simultaneously to avoid mutual interference.

[0034] When producing micron-sized powder, the system activates the gas atomization module alone. After the molten metal is delivered to the dual-mode atomization unit, only the gas atomization module is activated. High-purity inert gas at 2-8 MPa is introduced through the high-pressure gas channel, and the gas jet is ejected from the tightly coupled annular nozzle, directly impacting the annular liquid film formed by the molten metal flow. Due to the turbulent shear force of the high-speed gas flow, the liquid film is broken into micron-sized droplets, which then cool and solidify into coarse powder. In this mode, the laser irradiation atomization module is completely shut down, and the prepared micron-sized powder is transported to the subsequent radio frequency plasma spheroidization and heat treatment unit for spheroidization and purification.

[0035] The produced micron-sized powder is centrifuged and classified to obtain coarse and fine particles. The separated coarse particles are returned to the radio frequency plasma spheroidization and heat treatment unit. The fine powder particles are vibrated and sieved. Finally, the finished powder is collected and packaged in an inert atmosphere through an inert atmosphere packaging box.

[0036] Using the above preparation method, micron-sized powders for 3D printing (such as...) can be prepared. Figure 3 (As shown) or to meet different product needs for submicron or nano-sized powders for catalysis, quickly switch the corresponding atomization mode.

[0037] Example 3: This preparation method relies on a high-entropy alloy powder preparation furnace and is carried out in a continuous process of batching and melting, gas atomization, plasma spheroidization, and graded collection. Each step strictly corresponds to the raw material processing and vacuum melting unit, dual-mode atomization unit, radio frequency plasma spheroidization and heat treatment unit, and collection unit of the preparation furnace. The (FeCoNi) is achieved through the coordinated operation of each unit. 86 Precise preparation of Al7Ti7 high-entropy alloy micron-sized spherical powder. Specific operational steps are as follows: S1. Batching and smelting are carried out through the raw material processing and vacuum melting unit.

[0038] S11. Raw material pretreatment and vacuum feeding First, high-purity Fe, Co, Ni, Al, and Ti bulk raw materials undergo pretreatment. Mechanical grinding removes oxide scale, oil, and impurities from the raw material surface, followed by cleaning with anhydrous ethanol and drying to ensure the raw material purity meets preparation requirements. Then, the vacuum feeding chamber of the raw material processing and vacuum melting unit is opened, and its associated vacuum extraction system is activated to evacuate the inside of the feeding chamber until the preset vacuum level is reached, removing air from the chamber to prevent oxidation during raw material feeding. The pretreated Fe, Co, Ni, Al, and Ti bulk raw materials are then placed into the vacuum feeding chamber, and the chamber door is closed, maintaining a vacuum seal.

[0039] S22. Precise weighing and mixing The weighing mixer within the start-up unit quantitatively delivers raw materials from the vacuum feed hopper to the weighing chamber of the weighing mixer via a vacuum-sealed material conveying pipeline. (Based on FeCoNi) 86 To meet the atomic ratio design requirements of Al7Ti7, a weighing mixer precisely weighs the five raw materials—Fe, Co, Ni, Al, and Ti—with an error controlled within ±0.1%, ensuring that the proportions of each component accurately match the target composition. After weighing, the weighing mixer starts a low-speed stirring program to thoroughly mix the five raw materials for 15-20 minutes, ensuring uniform mixing and preventing component segregation during subsequent melting. After mixing, the mixed raw materials are fed into the furnace chamber of a vacuum induction melting furnace through a sealed conveyor channel.

[0040] S23. Vacuum induction melting and master alloy ingot forming Close the furnace door of the vacuum induction melting furnace, activate the integrated vacuum system inside the furnace, and continuously evacuate the furnace chamber until the required vacuum level for melting is reached (≤10). -3 Pa. Then, the medium-frequency induction power supply is activated, generating an alternating magnetic field through the induction heating coil inside the furnace to perform non-contact electromagnetic induction heating of the mixed raw materials, gradually raising the temperature to 1550-1650℃ and holding it at this temperature. Simultaneously, the electromagnetic stirring device inside the furnace is activated, continuously stirring the molten metal for 30 minutes. Electromagnetic force drives the convection of the molten metal, ensuring that the components Fe, Co, Ni, Al, and Ti are uniformly distributed in the molten metal. During the smelting process, cooling water is continuously circulated through the double-layer water-cooled jacket of the furnace body to achieve temperature control and prevent overheating and deformation. The polishing treatment of the inner wall effectively reduces the oxidation reaction between the molten metal and the furnace wall, as well as material adhesion. After smelting, a vacuum environment is maintained inside the furnace, and the rapid pouring mechanism on the furnace lid is activated to quickly and smoothly pour the uniformly composed molten metal into a pre-set water-cooled mold. After rapid cooling and solidification in the mold, (FeCoNi) is formed. 86 Al7Ti7 master alloy ingot. If subsequent atomization is required, the casting process can be omitted, and the molten metal can be directly delivered to the guide tube of the dual-mode atomization unit via a rapid pouring mechanism.

[0041] S2. Gas atomization is performed through a dual-mode atomization unit. The core of this step is to break the molten metal stream after remelting the master alloy ingot into tiny droplets to form powder, which is accomplished by the gas atomization module of the dual-mode atomization unit, and an inert atmosphere is maintained throughout the process to reduce oxidation.

[0042] S21. Remelting of master alloy ingots and melt transport The aforementioned prepared (FeCoNi) 86The Al7Ti7 master alloy ingot is placed in the vacuum induction melting furnace of the raw material processing and vacuum melting unit. The vacuum evacuation process is repeated, and the medium-frequency induction heating coil is restarted to remelt the master alloy ingot to a molten state of 1580-1650℃, ensuring that the master alloy ingot is completely melted and has a uniform composition. Subsequently, the remelted molten metal is precisely introduced into the atomization chamber of the gas atomization module of the dual-mode atomization unit through a vacuum-sealed guide tube. The guide tube is kept in an argon protective atmosphere throughout the process to prevent the molten metal from oxidizing due to contact with air during transportation.

[0043] S22. Gas atomization module debugging and atmosphere preparation The gas atomization module of the dual-mode atomization unit was pre-tested. The unobstructed flow and sealing performance of the annular slit of the tightly coupled annular nozzle at the bottom of the atomization chamber of the gas atomization module were checked to ensure no blockages or leaks. The connection and sealing of the high-pressure gas channel were also checked to ensure stable high-pressure gas delivery. Subsequently, high-purity argon gas was introduced into the atomization chamber of the gas atomization module through the high-pressure gas channel to displace the air inside and create an argon protective atmosphere. Simultaneously, the argon pressure was adjusted to stabilize at 5 MPa. At this point, the argon gas, after being delivered to the tightly coupled annular nozzle through the high-pressure gas channel, formed a supersonic argon flow with a velocity exceeding 540 m / s.

[0044] S23. Metal liquid atomization and coarse powder formation After flowing into the atomization chamber of the gas atomization module through the guide tube, the molten metal flows out through the annular channel of the tightly coupled annular nozzle, forming a uniform annular liquid film. At this point, a 5MPa supersonic argon gas flow is ejected from the annular slit of the tightly coupled annular nozzle, directly impacting the annular liquid film and rapidly and violently breaking it into numerous tiny metal droplets using strong turbulent shear force. The metal droplets are rapidly cooled in the argon atmosphere within the atomization chamber of the gas atomization module, and simultaneously undergo initial shaping under surface tension, ultimately solidifying to form (FeCoNi). 86 Al7Ti7 high-entropy alloy coarse powder. Under the influence of gravity, the coarse powder passes through a sealed channel at the bottom of the atomization chamber of the gas atomization module and enters the subsequent radio frequency plasma spheroidization and heat treatment unit.

[0045] S3. The plasma spheroidization step is carried out through the radio frequency plasma spheroidization and heat treatment unit.

[0046] The core of this step is to spheroidize, densify, and degas and purify the coarse powder formed by atomization, thereby improving the sphericity of the powder and reducing the oxygen content. This is accomplished by the coordinated operation of the radio frequency plasma torch, spheroidizing furnace, degassing and purification device, and water cooling tank in the radio frequency plasma spheroidizing and heat treatment unit, and is carried out entirely in an argon inert atmosphere.

[0047] S31. Unit Pretreatment and Atmosphere Creation Start the argon delivery system of the radio frequency plasma spheroidization and heat treatment unit, and introduce high-purity argon into the spheroidization furnace to replace the air inside the furnace and create a stable argon protective atmosphere. The argon flow rate is controlled within a preset range to ensure atmosphere stability. At the same time, start the unit's cooling system to ensure that the cooling function of the spheroidization furnace and water cooling tank is normal; check the operating status of the degassing and purification unit to ensure that it can properly perform its impurity evaporation and purification function.

[0048] S32. Start-up and parameter adjustment of the radio frequency plasma torch The 35kW radio frequency plasma torch within the start-up unit is activated, and the radio frequency power parameters are adjusted to ensure stable high-temperature plasma generation. Through debugging, the flame pattern of the plasma torch is ensured to be stable, and the location of the high-temperature zone is precisely matched with the coarse powder delivery path, providing a stable high-temperature environment for the subsequent instantaneous melting and spheroidization of the powder.

[0049] S33. Powder spheroidization, densification and purification The coarse powder formed by atomization enters the spheroidizing furnace of the radio frequency plasma spheroidizing and heat treatment unit through a sealed conveying pipeline, directly entering the high-temperature plasma region of the radio frequency plasma torch. Under the action of the high-temperature plasma, the coarse powder melts instantaneously, and the molten metal droplets shrink into spherical shapes under the action of surface tension. Simultaneously, the high-temperature environment promotes the healing of pores and defects inside the powder, achieving powder densification. During this process, the degassing and purification device operates concurrently. The high temperature of the plasma causes impurities in the powder, such as low-melting-point impurities like lead and sulfur, to evaporate instantly, achieving powder degassing and purification, and reducing the oxygen and impurity content of the powder.

[0050] S34. Spherical powder cooling and solidification The spheroidized, densified, and purified molten metal droplets are carried by an argon gas flow into the high-temperature zone of the spheroidizing furnace, and then flow through a water-cooling tank at the furnace outlet. The molten metal droplets rapidly solidify under the rapid cooling effect of the water-cooling tank, ultimately forming droplets like... Figure 4 The SEM image shows good sphericity (FeCoNi). 86 Al7Ti7 high-entropy alloy powder. The cooled spherical powder is transported to the collection unit through a sealed channel at the outlet of the water-cooling tank.

[0051] S4. Implement hierarchical collection steps through the collection unit.

[0052] The core of this step is to classify and screen the spheroidized powder to obtain finished powder with a particle size range of 15-53μm, and then collect and package it under an inert atmosphere. This is accomplished in collaboration with a multi-stage cyclone separator, vibrating screener, online particle size analyzer, and inert atmosphere packaging box in the collection unit.

[0053] S41. Primary Cyclone Separation and Classification The multi-stage cyclone separator and online particle size analyzer in the collection unit are activated. The spheroidized and cooled powder enters the multi-stage cyclone separator through a sealed channel. Using centrifugal force, the multi-stage cyclone separator separates large and fine powder particles in the airflow. Large particles are thrown to the inner wall of the separator by centrifugal force and then returned to the radio frequency plasma spheroidization and heat treatment unit for re-spheroidization through a return pipe. Fine powder particles that meet the initial particle size requirements are then carried by the airflow into the subsequent vibrating sieve. The online particle size analyzer monitors the particle size distribution of the powder in real time during the separation process to ensure that the separation effect meets the preset requirements.

[0054] S42. Secondary vibrating screen grading Start the vibrating screen and adjust the screen mesh to meet the 15-53μm particle size screening requirements. Fine powder from the multi-stage cyclone separator enters the vibrating screen, which then starts its vibration program, using high-frequency vibration to force the powder through the screen. Powder with a particle size <15μm passes through the screen and is separated, collected as a byproduct; powder with a particle size in the 15-53μm range is retained by the screen, completing secondary classification. During the screening process, the rotating shaft on the screen plate drives a double-helix pusher plate to slide against the screen plate, smoothly pushing the retained qualified powder outwards, avoiding the disorderly diffusion of powder and screen clogging in traditional vibrating screens, ensuring a highly efficient and stable screening process. An online particle size analyzer continuously monitors the particle size distribution of the qualified powder after screening to ensure it meets the target requirement of 15-53μm.

[0055] S43. Inert Atmosphere Collection and Encapsulation The inert atmosphere packaging box is started by first evacuating the interior to remove air, then introducing high-purity argon or nitrogen to create a stable inert atmosphere. The 15-53μm qualified powder, screened by a vibrating sieve, is then transported to the inert atmosphere packaging box through a closed conveyor pipeline. After collection, the packaging box is sealed to ensure the finished powder remains under inert atmosphere protection during storage and transportation, preventing oxidation and moisture absorption. Figure 3 As shown, the final obtained (FeCoNi) 86 The Al7Ti7 high-entropy alloy micron-sized spherical powder was tested and found to have a sphericity >95% and an oxygen content <200ppm, which meets the preset preparation requirements.

[0056] Example 4: Using CoCrFeNiAl 0.5 Taking the preparation of high-entropy alloy nanocatalysts as an example: S1. Raw material pretreatment High-purity Co, Cr, Fe, Ni, and Al metal blocks, with a purity ≥99.9%, are weighed in an equiatomic ratio, with Al element weighed at a ratio of 0.5. After the raw materials are acid-washed to remove oxide scale, they are vacuum-dried and introduced through a vacuum feeding hopper.

[0057] S2. Alternating laser irradiation atomization The system operates in a dual-mode alternating manner: the gas atomization module operates for 2 seconds for pre-crushing, and the laser irradiation module operates for 5 seconds for powder nano-sizing. The cycle alternates for 7 seconds. The laser parameters were set as follows: wavelength 1064 nm, pulse width 5 ns, repetition rate 50 kHz, and power density 5 × 10⁻⁶. 8 W / cm 2 The spot diameter is 30 μm, the scanning speed is 2 m / s, and the scanning range covers the trajectory of the falling molten metal. High-purity argon gas at 0.5 MPa is introduced into the atomization chamber of the gas atomization module. This is not the atomization pressure, but only maintains an inert atmosphere to prevent the nanopowder from oxidizing.

[0058] S3. Radiofrequency Plasma Spheroidization The collected nanoparticles were subjected to low-temperature plasma treatment: the radio frequency power was reduced to 10 kW and the argon flow rate was reduced to 15 L / min, so as to achieve surface micro-melting rather than complete globalization, retain the high specific surface area characteristics of the nanoparticles, and remove surface adsorbed impurities.

[0059] S4. Hierarchical Collection Electrostatic deposition + vacuum filtration is employed: after the nanoparticles are enriched by an electrostatic depositor, they are collected by vacuum filtration through a 0.1 μm microporous membrane in an inert atmosphere glove box, and finally packaged in a nitrogen-protected packaging box.

[0060] Prepared CoCrFeNiAl 0.5 The powder has an average particle size (D50) of 45 nm, an oxygen content of <300 ppm, and a specific surface area of ​​>35 m². 2 / g, suitable for electrocatalytic oxygen reduction reaction.

[0061] The above description is merely a preferred embodiment and the technical principles employed in this application. This application is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions that can be made by those skilled in the art will not depart from the scope of protection of this application. Therefore, although this application has been described in detail through the above embodiments, this application is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of this application.

Claims

1. A furnace for preparing high-entropy alloy powder, characterized in that, include: The raw material processing and vacuum melting unit, the dual-mode atomization unit, the radio frequency plasma spheroidization and heat treatment unit, and the collection unit; The raw material processing and vacuum melting unit is used to complete the vacuum melting of metal raw materials and provide molten metal. The dual-mode atomization unit includes a gas atomization module and a laser irradiation atomization module. When it is necessary to produce submicron or nano-sized powders, the gas atomization module and the laser irradiation atomization module are used alternately to scan the metal liquid flow or target material with a high-energy nanosecond pulsed laser, so that the metal is vaporized to form submicron or nano-sized powders. When it is necessary to produce micron-sized powders, the gas atomization module is used alone. The radio frequency plasma spheroidizing and heat treatment unit is used to receive the powder output from the dual-mode atomization unit and perform spheroidizing and purification treatment. The collection unit is used to collect the powder after spheroidization and purification in an inert atmosphere.

2. The preparation furnace according to claim 1, characterized in that, The raw material processing and vacuum melting unit includes a vacuum feeding hopper, a weighing mixer, and a vacuum induction melting furnace; the vacuum feeding hopper is used to quantitatively receive and transport metal raw materials in a vacuum environment; the weighing mixer is used to weigh and mix the metal raw materials; the vacuum induction melting furnace is used to melt the mixed raw materials into a molten metal and is equipped with a rapid pouring mechanism.

3. The preparation furnace according to claim 2, characterized in that, The vacuum induction melting furnace includes a vacuum system, an electromagnetic stirring device, an induction heating coil, and a double-layer water-cooled jacketed furnace body. The rapid pouring mechanism is installed on the furnace cover and is used to rapidly pour molten metal into the dual-mode atomization unit under vacuum or inert atmosphere.

4. The preparation furnace according to claim 1, characterized in that, The gas atomization module includes a tightly coupled annular nozzle and a high-pressure gas channel that cooperates with it; the laser irradiation atomization module includes a high-energy nanosecond pulse laser and an optical scanning mirror. The laser irradiation atomization module uses a high-energy nanosecond pulse laser, and the optical scanning mirror is used to guide the laser beam and quickly scan it onto the surface of the molten metal or alloy target, so that the metal is instantly vaporized to form fine droplets.

5. The preparation furnace according to claim 1, characterized in that, The radio frequency plasma spheroidizing and heat treatment unit includes: a radio frequency plasma torch for generating high-temperature plasma to instantly melt the powder; a spheroidizing furnace body surrounding the radio frequency plasma torch, internally divided into a spheroidizing region and a high-temperature region; a degassing and purification device integrated into the high-temperature region of the spheroidizing furnace body for evaporating impurities using high-temperature plasma to purify the powder; and a water-cooling tank located at the outlet end of the spheroidizing furnace body for rapidly cooling and solidifying the spherical powder.

6. The preparation furnace according to claim 1, characterized in that, The collection unit further includes: a multi-stage cyclone separator for centrifugally classifying the produced micron-sized powder to obtain coarse and fine particles, and returning the separated coarse particles to the radio frequency plasma spheroidization and heat treatment unit; a vibrating sieve equipped with a screen and a double-helix pusher plate for vibrating sieve of fine powder particles; and an inert atmosphere packaging box for collecting and packaging the finished powder under an inert atmosphere.

7. A method for preparing high-entropy alloy powder, wherein the powder is prepared using the furnace described in any one of claims 1-6, characterized in that, Includes the following steps: Metal raw materials are weighed and mixed in a vacuum environment, and then heated and melted into a metal melt in a vacuum induction melting furnace; Under the protection of an inert atmosphere, the molten metal is transported to a dual-mode atomization unit. When it is necessary to produce submicron or nano-sized powder, the gas atomization module and the laser irradiation atomization module are alternately activated. A high-energy nanosecond pulsed laser is used to scan the molten metal flow or the target material, causing the metal to vaporize and form submicron or nano-sized powder. When it is necessary to produce micron-sized powder, the gas atomization module is activated alone. Inert gas is used to break the molten metal into micron-sized powder through a tightly coupled annular nozzle. The generated powder is transported to the radio frequency plasma spheroidization and heat treatment unit, where the powder is instantly melted, spheroidized, densified and degassed and purified. Then it is rapidly cooled and solidified into spherical powder through a water cooling tank. The spherical powder was collected in a sealed manner under an inert atmosphere.

8. The preparation method according to claim 7, characterized in that, The laser irradiation atomization module uses a high-energy nanosecond pulsed laser to scan the metal liquid flow or target material with a laser beam of wavelength 1064nm, pulse width 3-10ns, and repetition frequency 10-100kHz, so that the metal vaporizes into submicron or nanoscale powder.

9. The preparation method according to claim 7, characterized in that, The produced micron-sized powder is centrifuged to obtain coarse and fine particles, and the separated coarse particles are returned to the radio frequency plasma spheroidization and heat treatment unit; the fine powder particles are vibrated and sieved; finally, the finished powder is collected and packaged in an inert atmosphere through an inert atmosphere packaging box.

Images