Water atomized metal powder and preparation method and application thereof

Abstract

The invention discloses a preparation method of water atomized powder. The preparation method comprises the following steps that S1, metal raw materials are smelted and deoxidized to obtain molten metal; s2, the molten metal obtained in the step S1 is subjected to atmosphere protection atomization, and powder slurry is obtained; and S3, dehydrating and drying the powder slurry obtained in the step S2. According to the method, the technical problems of high oxygen content and large apparent density of water atomized powder in the prior art are solved, and the content of impurity elements is effectively controlled. The invention further discloses the water-atomized metal powder prepared through the method and application of the water-atomized metal powder.

Description

Technical Field

[0001] This invention belongs to the field of powder material preparation technology, specifically relating to water-atomized metal powder, as well as the preparation method of water-atomized metal powder and its application. Background Technology

[0002] Water atomization powder production technology has become the main method for preparing powder raw materials in fields such as powder metallurgy (PM), metal injection molding (MIM), and additive manufacturing (AM) due to its advantages of simple process, low cost, and high efficiency. It can produce a variety of metal powders such as iron-based powder, nickel-based powder, copper-based powder, stainless steel powder, and soft magnetic material powder.

[0003] However, traditional water-atomized metal powders suffer from high bulk density and insufficient formability, making it difficult to meet the stringent requirements of high specific surface area and high porosity structures in applications such as filtration and separation, functional coatings, and catalyst supports. Furthermore, the high oxygen content in water-atomized powders not only reduces their own formability and sintering performance but also introduces oxide inclusions into the final product, severely damaging the material's mechanical properties and service life. To address these issues, two patents have been developed: one entitled "A Stainless Steel Alloy Powder and Its Preparation Method" (Publication No. CN115805314A, Publication Date 2023-03-17) and the other entitled "A Preparation Method of Stainless Steel Powder for Sintered Porous Metal Materials" (Publication No. CN117884640A, Publication Date 2024-04-16). These patents, by optimizing the smelting deoxidation process and controlling atomization parameters, achieve a certain degree of low bulk density and low oxygen content, but neglect the secondary oxidation problem caused by the decomposition of residual oxygen and water vapor during atomization. The patent, titled "A Deoxidation and Slag Removal Method for the Production of Low-Oxygen Stainless Steel Powder by Water Atomization" (publication number CN117467819A, publication date 2024-01-30), employs inert gas protection during the atomization process. However, it only introduces inert gas into the entire atomization chamber and fails to consider the significant differences in the oxidation mechanism and risk level of the molten metal flow at each stage from casting to solidification, resulting in a limited reduction in oxygen content. Summary of the Invention

[0004] The first objective of this invention is to provide a method for preparing water-atomized metal powder. Through systematic melting deoxidation and zoned atmosphere protection atomization technology, the technical problems of high oxygen content and high bulk density of water-atomized powder in the prior art are solved, and the content of impurity elements is effectively controlled.

[0005] A second objective of this invention is to provide water-atomized metal powder.

[0006] A third objective of this invention is to provide applications for water-atomized metal powders.

[0007] The first technical solution adopted in this invention is a method for preparing water atomized powder, comprising the following steps: Step S1: Melt and deoxidize the metal raw materials to obtain molten metal; Step S2: The molten metal obtained in step S1 is atomized under protective atmosphere to obtain a powder slurry; Step S3: Dehydrate and dry the powder slurry obtained in step S2.

[0008] The invention is further characterized in that: Step S1 is as follows: The metal raw material is placed in an induction melting furnace and heated and melted under the protection of nitrogen or argon. After the raw material is completely melted, a deoxidizer composed of ferrosilicon and calcium silicon is added in steps. After the deoxidizer is added, the mixture is allowed to stand and the slag is removed to obtain the molten metal. The standing time is 5 min to 8 min.

[0009] In step S1, after adding ferrosilicon and holding it at a temperature for 1-3 minutes, calcium silicon is added. The amount of deoxidizer composed of ferrosilicon and calcium silicon added, based on Si element, is 0.6 wt.% to 1.0 wt.% of the total mass of raw materials, of which Si introduced by calcium silicon accounts for 30 wt.% to 50 wt.% of the total Si added, and the remainder Si comes from ferrosilicon. The silicon content in ferrosilicon is 70 wt.% to 75 wt.%, and the remainder is Fe and unavoidable impurities. The silicon content in calcium silicon is 60 wt.% to 65 wt.%, the calcium content is 30 wt.% to 35 wt.%, and the remainder is unavoidable impurities.

[0010] Step S2 is as follows: Step 2.1: Preparation of atomization environment: Introduce argon or nitrogen into the atomization chamber to replace the air in the atomization chamber and obtain a low-oxygen atomization environment with an oxygen content ≤5 vol%. Step 2.2: Atomization Powdering: Adjust the position of the tundish crucible so that the center of its bottom drain is located on the central axis of the atomization system, ensuring that the freely falling molten metal flows through the geometric focus of water atomization; pour the molten metal obtained in step S1 into the tundish crucible with a preheated temperature of 600℃~800℃; after flowing out through the drain, the molten metal enters the atomization chamber and is broken into fine droplets by the high-pressure water jet from the atomization nozzle. During the atomization process, a zoned atmosphere protection is implemented. After the droplets are cooled and solidified under the protection of argon or nitrogen, they settle to the bottom of the collecting cylinder to obtain powder slurry; the pouring operation is stopped when the remaining amount of molten metal in the induction melting furnace is 5%~8% of the initial mass, as monitored by the liquid level. In step 2.2, the vertical distance between the geometric focus of water atomization and the plane containing the center point of the atomizing nozzle outlet is denoted as . H , H The specific relationship is determined based on the design parameters and installation angle of the atomizing nozzle, and satisfies the following formula: H =0.5L / tan( α / 2); In the formula, for a plate-shaped V-type atomizing nozzle, L This refers to the horizontal distance between the center points of the outlets of two oppositely positioned atomizing nozzles, corresponding to the geometric focus of water atomization; for linear flow ring orifice type atomizing nozzles, L The diameter of the distribution circle at the center point of the outlet of the annular array of atomizing nozzles, corresponding to the geometric focus of water atomization; α For a plate-flow V-shaped atomizing nozzle, the atomization angle is [missing information]. α The angle between the geometric center planes of the opposing water jets in the thickness direction, corresponding to the geometric focus of water atomization; for linear flow ring orifice type atomizing nozzles, α The apex angle of the theoretical cone formed by the central axes of each linear water jet, corresponding to the geometric focus of water atomization; In step 2.2, based on the geometric focus of water atomization, the atomization process is spatially divided into three functional zones, and zoned atmosphere protection is implemented. The three functional zones are as follows: First protection zone: The continuous liquid flow channel area located between the outlet of the leak at the bottom of the intermediate ladle crucible and the geometric focus of water atomization is designated as the first protection zone; Second protection zone: The space area from the geometric focus of water atomization to 150mm~250mm below the geometric focus of water atomization, where the metal liquid flow is atomized and broken up and the micro-droplets are initially formed, is the second protection zone; The third protection zone is the space from the lower boundary of the second protection zone to the bottom of the collection cylinder.

[0011] In step 2.2, a first protection zone is formed by setting up a first gas supply device, a second protection zone is formed by setting up a second gas supply device, and a third protection zone is formed by setting up a third gas supply device. The first gas supply device includes a first annular gas distribution pipeline and a first gas supply pipe. The first gas supply pipe is connected to the first annular gas distribution pipeline, and a plurality of first jet holes are evenly opened on the inner side of the first annular gas distribution pipeline. The second gas supply device includes a second annular gas distribution pipeline and a second gas supply pipe. Several second gas guide pipes are evenly arranged inside the second annular gas distribution pipeline, and the several second gas guide pipes and the second gas supply pipes are all connected to the second annular gas distribution pipeline. The second gas supply device and the third gas supply device have the same structure. The third gas supply device includes a third annular gas distribution pipeline and a third gas supply pipe. Several third gas guide pipes are evenly arranged inside the third annular gas distribution pipeline, and the several third gas guide pipes and the third gas supply pipes are all connected to the third annular gas distribution pipeline. The first gas supply device is located between the leak and the upper surface of the atomizing spray plate; the inner diameter of the first gas supply device D gas1 Based on the diameter of the leak d nozzle Design, i.e. D gas1 = d nozzle + ΔS 1. In the formula, ΔS 1 represents the radial safety clearance distance of the first gas supply device, which is the total difference in diameter between the inner wall of the first annular gas distribution pipeline and the inner wall of the leak. ΔS The value of 1 is 80mm~130mm; The first gas supply device supplies argon or nitrogen gas at a flow rate of 10L / min to 15L / min; The second gas supply device is located above the geometric focal point of the water atomization. H / 2, to the inner wall of the atomizing chamber within a space of 50mm below the geometric focus of water atomization; The second gas supply device supplies argon or nitrogen at a flow rate of 30L / min to 40L / min; If a single-layer third gas supply device is used, it is installed on the inner wall of the atomizing chamber in the gas phase space from 50mm above the lower boundary of the second protection zone to above the cooling water surface in the collection cylinder; when two or three layers of third gas supply devices are used, the top layer is installed at a horizontal position 50mm above the lower boundary of the second protection zone, and the vertical distance between each two adjacent layers is 150mm~250mm. If a single-layer third gas supply device is used, argon or nitrogen is supplied at a flow rate of 15 L / min to 25 L / min; if a two- or three-layer arrangement is used, the gas flow rate of the top layer is 15 L / min to 25 L / min, and the gas flow rate of each subsequent layer decreases by 5 L / min. This provides continuous atmospheric protection for the atomized particles in the third protection zone during the long cooling and solidification process. The minimum gas flow rate of the second gas supply device in the second protected area is greater than the maximum gas flow rate of the third gas supply device at the top of the third protected area; The inner diameter of the second gas supply device is D gas2 Based on the vertical installation position corresponding to the second gas supply device z Theoretical atomization cone diameter at the location D z2 Design, i.e. D gas2 = D z2 + ΔS 2; where, ΔS2 represents the radial safety clearance distance of the second gas supply device, i.e., the inner diameter of the second gas supply device. D gas2 The theoretical atomizing cone diameter at the corresponding vertical installation position z D z2 The total dimensional difference; where, ΔS 2 =S base2 + λD z2 In the formula, S base2 The basic safety distance for the second gas supply device is ΔS The fixed constant component of 2, the radial distance on one side of the foundation reserved for the second gas supply device is S base2 / 2; l For diffusion safety factor; The inner diameter of the third gas supply device is D gas3 Based on the vertical installation position corresponding to the third gas supply device z Theoretical atomization cone diameter at the location D z3 Design, i.e. D gas3 = D z3 + ΔS 3; In the formula, ΔS 3 represents the radial safety clearance distance of the third gas supply device, i.e., the inner diameter of the third gas supply device. D gas3 Its corresponding vertical installation position z Theoretical atomization cone diameter at the location D z3 The total dimensional difference; where, ΔS 3 =S base3 + λD z3 In the formula, S base3 The basic safety distance for the third gas supply device is ΔS 3 is a fixed constant component; the radial distance on one side of the foundation reserved for the third gas supply device is... S base3 / 2; l This is the diffusion safety factor.

[0012] In step S2.2, when the raw material used for the molten metal obtained in step S1 is stainless steel, the atomizing water pressure at the atomizing nozzle is 8MPa-10MPa, the water flow rate is 300L / min-350L / min, and the leak diameter is 6mm-8mm. When the raw material used for the molten metal obtained in step S1 is an iron-aluminum alloy, the atomizing water pressure at the atomizing nozzle is 12MPa-15MPa, the water flow rate is 250L / min-300L / min, and the diameter of the leak hole is 8mm-10mm.

[0013] Step S3 specifically involves: after filtering out water from the powder slurry obtained in step S2, drying it using a vacuum drying device at a temperature of 80℃~120℃ and a vacuum degree of not less than 1×10⁻⁶. -1 Pa, drying time is 2h~3h, and the dried powder is sieved to obtain water atomized metal powder with different particle size ranges.

[0014] The second technical solution adopted in this invention is water-atomized metal powder, which is prepared by the above-described method.

[0015] The third technical solution adopted in this invention is the application of water-atomized metal powder, in which the water-atomized metal powder prepared by the above method is used as a sintered metal filter, a porous catalyst carrier, a functional coating material, or a powder raw material for additive manufacturing.

[0016] The beneficial effects of this invention are: (1) The method of the present invention breaks through the mindset of overall atmosphere protection in the traditional atomization powder making process. It implements zoned inert atmosphere protection according to the oxidation risk characteristics of the molten metal flow and atomized particles at different stages. At the same time, silicon and calcium are used instead of manganese, the traditional deoxidizing element, to form a more protective oxide film on the surface of the melt, thereby significantly reducing the oxygen content of the powder.

[0017] (2) The method of this invention abandons the traditional slag removal methods of "scooping" and "blocking". After the slag removal process of smelting is completed, the deoxidation products and other oxides that are difficult to remove from the surface of the molten metal, especially the highly fluid and viscous liquid film products enriched on the surface of the molten metal, are actively retained in the smelting furnace along with a small amount of molten metal at the end of the casting process. This prevents the residue from entering the atomization system and forming impurities that contaminate the powder. This is particularly significant for the atomization effect of highly fluid molten metal. At the same time, it avoids the rapid cooling loss of the furnace lining after casting. The rich deoxidation element compounds can also play a slag layer protection role in the subsequent smelting process.

[0018] (3) The method of the present invention uses a low-pressure, high-flow-rate water jet to match a metal liquid flow with a hole diameter of similar size, which effectively reduces the risk of oxidation and process energy consumption while ensuring that the powder obtains a highly irregular morphology and a moderate particle size.

[0019] (4) The partitioned atmosphere protection technology of the present invention is applicable to the preparation of various metal powders such as stainless steel, iron-aluminum alloy, and nickel-based alloy. It can be achieved by adding a partitioned gas supply device on the basis of traditional water atomization equipment. The equipment modification cost is low, the process stability is reliable, and it is easy to promote and apply in industrial applications. Attached Figure Description

[0020] Figure 1 This is a schematic diagram illustrating the technical principle of the water atomization powder preparation process of this invention; Figure 2 This is a top view of the linear flow ring orifice type atomizing nozzle of the present invention; Figure 3 This is a top view of the plate-shaped V-shaped atomizing nozzle of the present invention; Figure 4 This is a schematic diagram of the atomization angle in this invention; Figure 5 This is a schematic diagram of the spatial coordinate system and theoretical atomization cone surface of the present invention; Figure 6 This is a top view of the first gas supply device used in this invention; Figure 7 This is a top view schematic diagram of the second gas supply device used in this invention; Figure 8 Microscopic morphology photographs of 100-160 mesh 316L stainless steel powder in Example 2; Figure 9 These are microscopic morphology photographs of the 40-150 mesh iron-aluminum alloy powder in Example 4.

[0021] In the diagram, 1. Induction melting furnace, 2. Tundish, 3. Tundish crucible, 4. Leak, 5. Atomizing spray plate, 6. Atomizing nozzle, 7. First gas supply device, 8. Second gas supply device, 9. Third gas supply device, 10. Geometric focus of water atomization, 11. First protection zone, 12. Second protection zone, 13. Third protection zone, 14. Atomization chamber, 15. Collector cylinder, 16. Molten metal flow, 17. Heating coil, 18. Insulation layer; 71. First annular gas distribution pipeline, 711. First gas supply pipe, 712. First jet hole.

[0022] 81. Second annular gas distribution pipeline, 811. Second gas supply pipe, 812. Second gas guide pipe. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0024] This invention provides a method for preparing water-atomized metal powder, comprising the following steps: Step S1: Melt and deoxidize the metal raw materials to obtain molten metal; Step S1 is as follows: The metal raw material is placed in the induction melting furnace 1 and heated and melted under the protection of nitrogen or argon. After the raw material is completely melted, a deoxidizer composed of ferrosilicon and calcium silicon is added in steps. After the deoxidizer is added, the mixture is allowed to stand and the slag is removed to obtain the molten metal. The standing time is 5 min to 8 min.

[0025] In step S1, after adding ferrosilicon and holding it at a temperature for 1-3 minutes, calcium silicon is added. The amount of deoxidizer composed of ferrosilicon and calcium silicon added, based on Si element, is 0.6 wt.% to 1.0 wt.% of the total mass of raw materials, of which Si introduced by calcium silicon accounts for 30 wt.% to 50 wt.% of the total Si added, and the remainder Si comes from ferrosilicon. The silicon content in ferrosilicon is 70 wt.% to 75 wt.%, with the remainder being Fe and unavoidable impurities. The silicon content in calcium silicon is 60 wt.% to 65 wt.%, the calcium content is 30 wt.% to 35 wt.%, and the remainder is unavoidable impurities. The metal raw materials are stainless steel or iron-aluminum alloy; the stainless steel used is 310S, 316L, or 304 stainless steel, and the molten metal superheat is 150℃ to 250℃. The iron-aluminum alloy used, by mass percentage, has an aluminum content of 10wt.%-20wt.%, a Cr content of 4wt.%-6wt.%, and the balance is iron and unavoidable impurities; the molten metal superheat is 200℃ to 300℃. Step S2: The molten metal obtained in step S1 is atomized under protective atmosphere to obtain a powder slurry; Step S2 is as follows: Step 2.1: Preparation of atomization environment: Argon or nitrogen gas is introduced into the atomization chamber 14 to replace the air in the atomization chamber 14 and obtain a low-oxygen atomization environment with an oxygen content ≤5 vol%. Step 2.2: Atomization Powdering: Adjust the position of the tundish crucible 3 so that the center of its bottom hole 4 is located on the central axis of the atomization system, ensuring that the freely falling molten metal flow 16 passes through the water atomization geometric focus 10; pour the molten metal obtained in step S1 into the tundish crucible 3 with a preheated temperature of 600℃~800℃; after the molten metal flows out through the hole 4, it enters the atomization chamber 14 and is broken into fine droplets by the high-pressure water jet from the atomization nozzle 6. During the atomization process, a zoned atmosphere protection is implemented. After the droplets are cooled and solidified under the protection of argon or nitrogen, they settle to the bottom of the collection cylinder 15 to obtain powder slurry; the pouring operation is stopped when the remaining amount of molten metal in the induction melting furnace 1 is 5%~8% of the initial mass by liquid level monitoring, to avoid the newly formed deoxidation products and other oxide inclusions enriched on the surface of the molten metal after slag removal being carried into the atomization process; In step 2.2: like Figure 1As shown, the atomization system used in this invention includes: an intermediate ladle 2, an atomizing spray plate 5, an atomizing chamber 14, and a collecting cylinder 15 arranged sequentially from top to bottom; the intermediate ladle 2 contains an intermediate ladle crucible 3, a heating coil 17, and a heat insulation layer 18, with the heating coil 17 wound around the outer periphery of the intermediate ladle crucible 3, and a hole 4 provided at the bottom of the intermediate ladle crucible 3; the heat insulation layer 18 is located below the intermediate ladle crucible 3 and the heating coil 17 to support the intermediate ladle crucible 3 and the heating coil 17, and a through hole is opened at the center of the heat insulation layer 18 to ensure that the molten metal flow 16 can pass through smoothly; the bottom of the atomizing spray plate 5 is provided with several atomizing nozzles 6; the outlet of the hole 4 is located above the upper surface of the atomizing spray plate 5; and an induction melting furnace 1 is also included.

[0026] To ensure that the spatial positioning, distance measurement, or area division in this invention has a unified and repeatable measurement benchmark and implementation standard, this invention first establishes a unified spatial geometric reference system.

[0027] (1) Determination of the geometric focus 10 of water atomization: This invention defines the "geometric focus of water atomization" as the unified reference origin for the installation position, area division and parameter calculation of each component in the atomization system, denoted as point O.

[0028] The water atomization geometric focus 10 is a theoretical spatial point determined by geometric principles based on the design structural parameters and installation angle of the atomizing nozzle. Specifically, it is defined as the theoretical spatial intersection of the central axis or geometric center plane of the water jet formed by the atomizing nozzle 6 with the central axis of the atomization system when extended along the spray direction.

[0029] The central axis of the atomization system is the alignment reference line when assembling the tundish 2, tundish crucible 3, bottom hole of the tundish crucible 4, atomizing spray plate 5, and all atomizing nozzles 6. For atomizing nozzles of different structural types, the water atomization geometric focus 10 specifically refers to the following: like Figure 2 As shown, for a linear flow ring orifice type atomizing nozzle, the central axis of the linear water jet formed by each atomizing nozzle 6 extends downward in space along the spray direction and intersects at the theoretical intersection point on the central axis of the atomizing system, which is the water atomization geometric focus 10.

[0030] like Figure 3 As shown, for a plate-shaped V-shaped atomizing nozzle, the theoretical intersection point formed by the geometric center plane of the plate-shaped water jet in the thickness direction extending downward in space along the spray direction of the atomizing nozzle 6 and the theoretical intersection point with the central axis of the atomizing system is the water atomization geometric focus 10.

[0031] When the atomizing nozzle 6 is designed to generate multiple theoretical intersection points, the theoretical intersection point that flows along the molten metal flow 16 to the upstream (i.e. the one closest to the bottom of the leak outlet) is taken as the water atomization geometric focus 10.

[0032] It should be understood that during actual atomization, the high-pressure water jet will form an energy concentration area with a certain range near the theoretical intersection point and will have a breaking effect on the molten metal flow. The water atomization geometric focus 10 in this invention is only used as a theoretical geometric reference point for spatial positioning, distance measurement, and area division. Its purpose is to provide a unified spatial reference and is not used to limit the actual physical energy distribution range.

[0033] (2) Calculation of the positioning of the water atomization geometric focus 10: The position of the water atomization geometric focus 10 is an inherent design feature of the atomization system, which is determined during the equipment manufacturing and assembly stages. like Figure 4 As shown, the vertical distance between the water atomization geometric focus 10 and the plane containing the center point of the water outlet of the atomizing nozzle 6 is denoted as . H , H The specific relationship is determined based on the design parameters and installation angle of the atomizing nozzle, and satisfies the following formula: H =0.5 L / tan( α / 2).

[0034] In the formula, for a plate-shaped V-type atomizing nozzle, L To form the horizontal distance between the center points of the outlets of the two oppositely arranged atomizing nozzles 6 corresponding to the water atomization geometric focus 10; for linear flow ring orifice type atomizing nozzles, L The diameter of the distribution circle at the center point of the outlet of the annular array atomizing nozzle 6 corresponding to the water atomization geometric focus 10; α For a plate-flow V-shaped atomizing nozzle, the atomization angle is [missing information]. α To form the angle (full angle) between the geometric center planes of the opposing water jets in the thickness direction, corresponding to the geometric focus 10 of the water atomization; for linear flow ring orifice type atomizing nozzles, α The apex angle of the theoretical cone formed by the central axes of each linear water jet, corresponding to the geometric focus 10 of water atomization.

[0035] (3) Establishment of spatial coordinate system: like Figure 5 As shown, a rectangular coordinate system is established with the water atomization geometric focus 10 as the origin of the spatial coordinate system O (0,0,0) and the central axis of the atomization system as the Z-axis (vertical direction, the same as the flow direction of the molten metal 16). Taking the molten metal flow in 16 directions (from top to bottom) as... ZPositive axis direction, at the origin O z =0, above the origin O. z The value is negative, below z The value is positive; unless otherwise stated, all distances in this invention relating to "vertical installation position," "above," and "below" refer to distances along the axis with the origin O as the reference. Z Vertical distance along the axis.

[0036] (4) Determination of the theoretical atomization cone surface: like Figure 5 As shown, the straight line starting from the center point of the water outlet of the water atomizing nozzle 6 and passing through the water atomizing geometric focus 10 is regarded as the "theoretical jet characteristic line" of the high-pressure water jet; the theoretical jet characteristic line rotates around the central axis of the atomization system to form an "hourglass-shaped" rotation trajectory surface with the water atomizing geometric focus 10 as the center of symmetry, which is defined as the "theoretical atomization cone surface" of the present invention; the theoretical atomization cone surface is used to define the safety boundary of the equipment installation and the reference boundary of the airflow coverage.

[0037] exist Z Any vertical position of the axis z At that point, the theoretical diameter corresponding to the theoretical atomization cone surface D z Satisfy geometric relations: D z =2·| z |·tan( α / 2); In the formula, | z | represents the absolute value of the vertical distance from this position to the origin O.

[0038] It should be understood that this definition assumes that the theoretical divergence angle of the high-pressure water jet after passing through the water atomization geometric focus 10 is the same as the incident angle. This conical surface is mainly used to define the radial installation safety boundary of the equipment and the reference boundary of the airflow coverage, and does not limit the actual atomization range.

[0039] like Figure 1 As shown, based on the above-established unified spatial geometric reference system, this invention, according to the morphological transformation process and oxidation risk of the molten metal flow 16 to the powder, uses the water atomization geometric focus 10 as a reference to divide the atomization process into three functional regions in space, and implements functionally independent and synchronously controlled zoned atmosphere protection. The three functional regions are specifically as follows: First protection zone 11 (liquid flow channel zone): the continuous liquid flow channel region located between the outlet of the bottom leak 4 of the intermediate ladle crucible 3 and the water atomization geometric focus 10 (i.e. z <0), serving as the first protected area 11; within this area, the molten metal flow 16 is mainly in the form of a continuous liquid column, and the main risk is oxidation of the liquid flow surface.

[0040] Second protection zone 12 (atomization breakup zone): The space region from the water atomization geometric focus 10 to the initial formation of micro-droplets of the metal liquid flow 16 atomization breakup and micro-droplet formation 150mm~250mm below the water atomization geometric focus 10 is the second protection zone 12; in this region, the metal liquid flow 16 is mainly broken into micro-droplets, the specific surface area of ​​the molten metal increases sharply, and the risk of oxidation of atomized particles is the highest.

[0041] The third protection zone 13 (cooling and solidification zone): The space from the lower boundary of the second protection zone 12 (i.e., z>150mm~250mm) to the bottom of the collection cylinder 15 is the third protection zone 13; in this zone, the atomized droplets are mainly in the flight, cooling and solidification stage, the temperature gradually decreases but the exposure time is relatively long.

[0042] For the three functional areas mentioned above, based on the aforementioned spatial reference, this invention configures independently controlled zoned gas protection devices, specifically as follows: The zoned atmosphere protection device includes a first gas supply device 7, a second gas supply device 8, and a third gas supply device 9 arranged from top to bottom along the central axis of the atomization system. These three devices provide independent and synchronously controlled zoned atmosphere protection. The first gas supply device 7 forms a first protection zone 11, the second gas supply device 8 forms a second protection zone 12, and the third gas supply device 9 forms a third protection zone 13. Each gas supply device adopts a ring-shaped arrangement, including gas distribution pipelines and multiple central axis pointing devices distributed inside the pipelines. Z The jet orifice or guide tube of the shaft is used to form an airflow curtain that converges towards the center. The cross-section of the annular gas distribution pipe is rectangular or circular.

[0043] like Figure 6 As shown, the first gas supply device 7 includes a first annular gas distribution pipe 71 and a first gas supply pipe 711. The first gas supply pipe 711 is connected to the first annular gas distribution pipe 71. A plurality of first jet holes 712 are evenly opened on the inner side of the first annular gas distribution pipe 71.

[0044] like Figure 7As shown, the second gas supply device 8 includes a second annular gas distribution pipeline 81 and a second gas supply pipe 811. A plurality of second gas guide pipes 812 are evenly arranged inside the second annular gas distribution pipeline 81, and both the plurality of second gas guide pipes 812 and the second gas supply pipes 811 are connected to the second annular gas distribution pipeline 81. The second gas supply device 8 and the third gas supply device 9 have the same structure. The third gas supply device 9 includes a third annular gas distribution pipeline and a third gas supply pipe. A plurality of third gas guide pipes are evenly arranged inside the third annular gas distribution pipeline, and both the plurality of third gas guide pipes and the third gas supply pipe are connected to the third annular gas distribution pipeline. The arrangement of the first gas supply device 7, the second gas supply device 8, and the third gas supply device 9 avoids the situation where high-pressure water jet splashes back or high-temperature molten metal droplets directly damage the main gas supply pipeline.

[0045] In the structure of the second gas supply device 8 and the third gas supply device 9, the "inner diameter of the gas supply device" involved in this invention uniformly refers to the diameter of the geometric circle formed by the center points of the outlet end faces of all the gas guide pipes in space; specifically installed on the inner wall of the atomizing chamber, the outlet is adjusted to ensure that the gas guide pipe reaches the designed "inner diameter of the gas supply device" position.

[0046] The first gas supply device 7 is located between the leak 4 and the upper surface of the atomizing spray plate 5; the inner diameter of the first gas supply device 7 D gas1 Based on the 4-diameter leak d nozzle Design, i.e. D gas1 = d nozzle + ΔS 1. In the formula, ΔS 1 represents the radial safety clearance distance of the first gas supply device 7, which is the total difference in diameter between the inner wall of the first annular gas distribution pipe 71 and the inner wall of the leak 4; considering the stability of the molten metal flow and the negative pressure effect of the high-pressure water jet, ΔS 1. The value is 80mm~130mm; inert protective gas is supplied to the metal liquid flow 16 in the first protection zone 11 through the first gas supply device 7 to form an inert atmosphere protective layer to prevent the continuous liquid flow from undergoing surface oxidation before it breaks.

[0047] The first gas supply device 7 supplies argon or nitrogen gas at a flow rate of 10L / min to 15L / min; a protective gas curtain is formed below the leak outlet in the first protection zone 11 to cover the liquid flow channel area and prevent the continuous metal liquid flow from undergoing surface oxidation before it breaks.

[0048] The second gas supply device 8 is positioned above the water atomization geometric focal point 10. H / 2, within a space of 50mm below the water atomization geometric focus 10 (i.e., z=﹣) H / 2 to z =50mm) on the inner wall of the atomization chamber; inert protective gas is supplied to the atomization core area in the second protection zone 12 where the metal liquid flow 16 is broken by the high-pressure water jet through the second gas supply device 8; the entrainment effect generated by the high-pressure water jet allows the gas to effectively enter the area, and an oxygen barrier is established around the micro-droplets formed at the moment the metal liquid flow 16 is broken and after the break, to ensure that the newly generated high-temperature, high specific surface area metal droplets are isolated from oxygen.

[0049] The second gas supply device 8 supplies argon or nitrogen gas with a flow rate of 30L / min~40L / min; under the entrainment effect generated by the atomizing nozzle, the airflow enters the atomization core area of ​​the metal liquid flow 16 in the second protection zone 12, which is broken by the high-pressure water jet. An oxygen barrier is established around the micro-droplets formed at the moment the metal liquid flow 16 is broken and after the breakage, to ensure that the newly generated high-temperature, high specific surface area metal liquid droplets are isolated from oxygen. If a single-layer third gas supply device 9 is used, it is positioned 50mm above the lower boundary of the second protection zone 12 (i.e., z =100mm~200mm) to the inner wall of the atomizing chamber in the gas phase space above the cooling water surface inside the collecting cylinder 15; when two or three layers of third gas supply devices 9 are used for gas supply, the top layer is set at a horizontal position 50mm above the lower boundary of the second protection zone 12 ( ... z =100mm~200mm), the vertical spacing between each two adjacent layers is 150mm~250mm; argon or nitrogen is supplied to the cooling and solidification path of the atomized particles in the third protection zone 13 through the third gas supply device 9, so as to provide continuous atmosphere protection for the atomized particles during the long cooling and solidification process.

[0050] If a single-layer third gas supply device 9 is used, argon or nitrogen is supplied at a flow rate of 15 L / min to 25 L / min; if a two- or three-layer arrangement is used, the gas flow rate of the top layer is 15 L / min to 25 L / min, and the gas flow rate of each subsequent layer decreases by 5 L / min. This provides continuous atmospheric protection for the atomized particles in the third protection zone during the long cooling and solidification process. The minimum gas flow rate of the second gas supply device 8 in the second protected area 12 is greater than the maximum gas flow rate of the top-level third gas supply device 9 in the third protected area; Vertical installation positions of the second gas supply device 8 and the third gas supply device 9 z All measurements are based on the horizontal plane where the center of the cross-section of the annular gas distribution pipe is located. The inner diameter of the second gas supply device 8 is D gas2Based on the vertical installation position corresponding to the second gas supply device 8 z Theoretical atomization cone diameter at the location D z2 Design, i.e. D gas2 = D z2 + ΔS 2; where, ΔS 2 represents the radial safety clearance of the second gas supply device 8, i.e., the inner diameter of the second gas supply device 8. D gas2 The theoretical atomizing cone diameter at the corresponding vertical installation position z D z2 The total dimensional difference. Among them, ΔS 2 =S base2 + λD z2 In the formula, S base2 The basic safety distance for the second gas supply device 8 is ΔS 2 is a fixed constant component. That is, in the atomization space, starting from the theoretical atomization cone surface, to adapt to fluid diffusion and avoid the impact and interference of the jet on the device, the radial distance on one side of the foundation reserved by the second gas supply device 8 is... S base2 / 2; l The diffusion safety factor is used to compensate for the additional risks brought about by the diffusion of high-temperature and high-pressure water jets carrying atomized particles.

[0051] The inner diameter of the third gas supply device 9 is D gas3 Based on the vertical installation position corresponding to the third gas supply device 9 z Theoretical atomization cone diameter at the location D z3 Design, i.e. D gas3 = D z3 + ΔS 3; In the formula, ΔS 3 represents the radial safety clearance distance of the third gas supply device 9, i.e., the inner diameter of the third gas supply device 9. D gas3 Its corresponding vertical installation position z Theoretical atomization cone diameter at the location D z3 The total dimensional difference. Among them, ΔS 3 =S base3 + λD z3 In the formula, Sbase3 The basic safety distance for the third gas supply device 9 is ΔS 3 is a fixed constant component. That is, in the atomization space, starting from the theoretical atomization cone surface, to adapt to fluid diffusion and avoid the impact and interference of the jet on the device, the radial distance on one side of the foundation reserved by the third gas supply device 9 is... S base3 / 2; l The diffusion safety factor is used to compensate for the additional risks brought about by the diffusion of high-temperature and high-pressure water jets carrying atomized particles.

[0052] Considering the stability of the molten metal flow and the negative pressure effect of the high-pressure water jet, the foundation safety distance of the second gas supply device 8 is... S base2 The value is taken as 100mm; considering the actual physical dispersion and water mist splashing after the high-pressure water jet impacts the molten metal flow, the basic safety distance of the third gas supply device 9 is... S base3 The value is 130 mm; diffusion safety factor. l The value ranges from 0.1 to 0.3. In the same embodiment of the atomization system, the coefficient l Take a fixed constant, or take the origin O as the starting point and vary along the Z-axis with vertical height | z The increase of | remains monotonically constant, making the second gas supply device 8 D gas2 and the third gas supply device 9 D gas3 Overall Z Along the axial direction, starting from the origin O along Z Axial direction varies with vertical height | z | increases monotonically as it increases.

[0053] The gas supply device, by adding a safety clearance distance on top of the leak diameter or theoretical atomization cone diameter, ensures that the gas outlet of each gas supply device is located outside the envelope formed by the molten metal flow or high-pressure water jet, thereby ensuring that the airflow curtain completely covers the molten metal flow 16 or atomized particles, without affecting the flow pattern stability of the molten metal flow 16, and without physical interference with the high-pressure water jet.

[0054] It should be noted that the location, structure, and flow parameters of the gas supply devices corresponding to each protected area in this invention are mainly based on the following considerations: During atomization, the high-pressure water jet will create a local negative pressure in the inlet area of ​​the atomizing spray plate. This negative pressure effect is beneficial for the inert gas above the inlet to be drawn into the atomization chamber. At the same time, the main airflow direction driven by the high-speed water jet in the chamber is from top to bottom, which helps to maintain the longitudinal coverage of the protective atmosphere. Secondly, the inert gas needs to travel a certain diffusion distance after being ejected from the supply device to form an effective atmosphere barrier in the target protected area. In addition, if the gas supply device is too close to the atomization core area where the molten metal 16 is broken by the high-pressure water jet, or if the gas flow rate is inappropriate, its jet airflow may disturb the stability of the liquid flow or interfere with the breaking efficiency of the water jet, thereby reducing the atomization effect. Therefore, the location of each gas supply device is not entirely within the geometric boundary of the target protected area. This allows the inert gas to form an overlapping atmosphere at the junction of the two regions after spreading a certain distance. This ensures that the resulting converging airflow curtain can completely cover and penetrate the corresponding target protection zone, thereby achieving precise and timely atmosphere protection for each morphological transformation area while avoiding adverse effects on the atomization process.

[0055] In step S2.2, when the raw material used for the molten metal obtained in step S1 is stainless steel, the atomizing water pressure at the atomizing nozzle 6 is 8MPa-10MPa, the water flow rate is 300L / min-350L / min, and the diameter of the leak 4 is 6mm-8mm.

[0056] When the raw material used for the molten metal obtained in step S1 is an iron-aluminum alloy, the atomizing water pressure at the atomizing nozzle 6 is 12MPa-15MPa, the water flow rate is 250L / min-300L / min, and the diameter of the leak 4 is 8mm-10mm.

[0057] Step S3: Dehydrate and dry the powder slurry obtained in step S2.

[0058] Step S3 specifically involves: after filtering out water from the powder slurry obtained in step S2, drying it using a vacuum drying device at a temperature of 80℃~120℃ and a vacuum degree of not less than 1×10⁻⁶. -1 Pa, drying time is 2h~3h, and the dried powder is sieved to obtain water atomized metal powder with different particle size ranges.

[0059] This invention also provides water-atomized metal powder, prepared using the method described above. The prepared water-atomized metal powder is stainless steel powder or iron-aluminum alloy powder, with a highly irregular powder morphology and characterized by low bulk density and low oxygen content. The stainless steel powder is 310S, 316L, or 304, and after sieving, the bulk density of the stainless steel powder in the 60-100 mesh and 100-160 mesh particle size range is 1.8-2.3 g / cm³, with an oxygen content ≤0.18 wt%. The iron-aluminum powder is an iron-aluminum alloy powder with an aluminum content of 10-20 wt.% and a Cr content of 4-6 wt.%, and after sieving, the bulk density of the iron-aluminum powder in the 40-150 mesh particle size range is 1.4-1.6 g / cm³, with an oxygen content ≤0.2 wt%.

[0060] The present invention also provides the application of the above-mentioned water-atomized metal powder in the preparation of porous materials, wherein the water-atomized metal powder is used as a sintered metal filter, a porous catalyst carrier, a functional coating material or a powder raw material for additive manufacturing.

[0061] The technical concept of this invention is based on the following technical principles: the morphological evolution of molten metal flowing into powder during water atomization can be divided into three distinct stages, each with significantly different oxidation mechanisms and risk levels: the continuous liquid column in the liquid flow channel region has a high temperature but a small specific surface area; the specific surface area of ​​the fine droplets in the atomization fragmentation zone increases sharply while the temperature remains high, resulting in the highest oxidation risk; and the particle temperature in the cooling and solidification zone gradually decreases, but the exposure time is long. Traditional overall atmosphere protection methods cannot provide precise protection for the characteristics of each stage. Therefore, this invention achieves comprehensive, differentiated, and targeted protection for the molten metal flow and atomized particles by setting independent gas supply devices in different functional areas. Simultaneously, a silicon-iron-silicon-calcium composite deoxidizer is used to improve deoxidation efficiency; the timing of pouring cessation is controlled to avoid introducing oxide inclusions enriched on the molten surface; and powder morphology and cooling rate are controlled through atomization parameters to further reduce oxidation risk.

[0062] Example 1 The preparation method of water-atomized 310S powder includes the following steps: Step S1: Melt and deoxidize the metal raw materials to obtain molten metal; 310S stainless steel raw material, formulated from pure iron, pure nickel, and ferrochrome alloy, was placed in an induction melting furnace and heated and melted under argon protection. After the raw material was completely melted, ferrosilicon was added first, and the mixture was held at this temperature for 3 minutes to allow for a complete reaction. Then, calcium silicon was added. The total amount of deoxidizer added, based on Si element, was 1.0 wt.% of the total raw material mass. Of this, Si in the calcium silicon accounted for 30 wt.% of the total Si added, with the remainder coming from the ferrosilicon. The ferrosilicon contained 75 wt.% silicon, with the remainder being Fe and unavoidable impurities; the calcium silicon contained 65 wt.% silicon and 30 wt.% calcium, with the remainder being unavoidable impurities. After all the deoxidizer was added, the mixture was allowed to stand for 6 minutes to allow the slag to float to the surface. After thoroughly removing the slag, a clean, low-oxygen molten metal with a superheated temperature of 250°C was obtained.

[0063] Step S2: The molten metal obtained in step S1 is atomized under protective atmosphere to obtain a powder slurry; Step 2.1: Preparation of atomization environment: Argon gas is introduced into the atomization chamber to replace the air in the atomization chamber and obtain a low-oxygen atomization environment with an oxygen content ≤5 vol%. Step 2.2: Atomization and Powder Formation: Before atomization, adjust the position of the tundish crucible so that the center of its bottom drain is located on the central axis of the atomization system. Pour the molten 310S stainless steel obtained in step S1 into the tundish crucible 3, which has been preheated to 800℃. The molten liquid flows out through the 6mm diameter drain at the bottom of the crucible 3 and enters the atomization chamber, where it is atomized at an angle... α The high-pressure water jet, with a pressure of 8 MPa and a flow rate of 300 L / min, is broken into fine droplets by a 40° linear flow ring orifice type single-focus atomizing nozzle. The casting operation is stopped when the remaining molten liquid in the melting furnace reaches 5% of the initial mass, through liquid level monitoring, to avoid deoxidation products being carried into the atomization process.

[0064] The linear flow ring orifice type single-focus water atomizing nozzle used in this embodiment forms a high-pressure water jet. (Top view schematic diagram follows) Figure 2 As shown. The theoretical intersection point where the central axis of the linear water jet formed by the atomizing nozzle extends along the spray direction and intersects with the central axis of the atomizing system where the freely falling molten metal 16 is located is taken as the water atomization geometric focus 10 in this embodiment.

[0065] Diameter of the distribution circle at the center point of the atomizing nozzle 6 outlet L =90mm, forming the apex angle of the theoretical cone formed by the central axes of all linear water jets corresponding to the geometric focus 10 of water atomization, i.e., the atomization angle. α =40°, according to the formula H =( L / 2) / tan( α / 2) Calculate the vertical distance below the plane where the water atomization geometric focus 10 of this embodiment is located at the water outlet of the atomizing nozzle 6. H On the central axis of the atomization system at approximately 124 mm.

[0066] Using the water atomization geometric focus 10 as the origin of the spatial coordinate system O(0,0,0), the central axis of the atomization system is... Z Establish a spatial rectangular coordinate system with the axis as the axis. The direction of the molten metal flow (from top to bottom) is used as the axis. Z Positive axis direction. During atomization, zoned atmosphere protection is implemented: First protected zone 11 (liquid flow channel area): The continuous liquid flow channel area located between the outlet of the bottom leak 4 of the intermediate ladle crucible 3 and the geometric focus of water atomization 10 (i.e., z <0). With the central axis of the atomization system Z Centered on the axis, an annular first gas supply device 7 is set on the upper end face of the atomizing spray disk 5.

[0067] The first gas supply device 7 consists of an annular gas distribution pipe, a gas supply pipe connected to it, and a gas supply pipe located inside the gas distribution pipe and pointing radially. Z The shaft consists of jet holes. The inner diameter of the first gas supply device 7... D gas1 According to the diameter of the leak d nozzle =6mm and safe clearance ΔS 1 = 130mm, calculated and determined, that is D gas1 = d nozzle + ΔS 1 = 136 mm.

[0068] Argon gas with a flow rate of 10 L / min is supplied to the metal liquid flow 16 in the first protected area through the first gas supply device 7 to form an inert atmosphere protective layer and prevent the continuous liquid flow from undergoing surface oxidation before it breaks. Second Protection Zone 12 (Atomization and Breakup Zone): The spatial region located from the geometric focus of water atomization 10 to 150 mm below it, where the metal liquid flow 16 atomizes and breaks up, and where fine droplets initially form (i.e., 0 mm ≤ z ≤150mm). With the central axis of the atomization system as the guide. Z Centered on the axis, at the horizontal position of the water atomization geometric focus 10 (i.e. z On the inner wall of the atomizing chamber at 0mm, an annular second gas supply device 8 is installed, with its vertical installation position measured on the horizontal plane where the center of the cross-section of its annular gas distribution pipeline is located.

[0069] The second gas supply device 8 consists of an annular gas distribution pipeline, a gas supply pipeline connected to it, and several gas guide pipes located inside the distribution pipeline and extending radially towards the center. The inner diameter of the second gas supply device 8... D gas2 Let be the diameter of the geometric circle formed by the center points of the end faces of all air outlets in the guide tubes. Based on the theoretical formula for the diameter of the atomizing cone... D z =2·| z |·tan( α / 2), calculate the vertical installation position of the second gas supply device 8. z =0mm D z2 =0mm. According to the formula... ΔS 2= S base2 + λD z2 Set the basic safety distance for the second gas supply device 8. S base2 =100mm, diffusion safety factor l Using a value of 0.1, the safe avoidance distance is calculated. ΔS 2= S base2 + λD z2 =100mm + 0.1 × 0mm = 100mm. The inner diameter of the second gas supply device 8 is thus determined. D gas2 = D z2 + ΔS 2 = 0mm + 100mm = 100mm.

[0070] Argon gas at a flow rate of 30 L / min is supplied to the atomization core area of ​​the metal liquid flow broken by the high-pressure water jet within the second protection zone 12 through the second gas supply device 8. Utilizing the entrainment effect generated by the high-pressure water jet, the gas effectively enters this area, establishing an oxygen barrier around the micro-droplets formed at the moment the metal liquid flow 16 is broken and after the breakage, ensuring that the newly generated high-temperature, high-specific-surface-area metal droplets are isolated from oxygen. Third Protection Zone 13 (Cooling and Solidification Zone): The space from the lower boundary of Second Protection Zone 12 to the bottom of Collection Cylinder 15 (i.e., z >150mm). With the central axis of the atomizing system as the guide. Z Centered on the axis, at a horizontal position 50mm above the lower boundary of the second protected area 12 (i.e. z On the inner wall of the atomizing chamber at a distance of 100mm, a ring-shaped third gas supply device 9 is installed, with its vertical installation position measured on the horizontal plane where the center of the cross-section of its ring-shaped gas distribution pipeline is located.

[0071] The third gas supply device 9 consists of an annular gas distribution pipeline, a gas supply pipeline connected to it, and several gas guide pipes located inside the distribution pipeline and extending radially towards the center. The inner diameter of the third gas supply device 9... D gas3 Let be the diameter of the geometric circle formed by the center points of the end faces of all air outlets in the guide tubes. Based on the theoretical formula for the diameter of the atomizing cone... D z =2·| z |·tan( α / 2), calculate the vertical installation position of the third gas supply device 9. z =100mm D z3 =73mm. According to the formula... ΔS 3= S base3 + λD z3 Set the basic safety distance for the third gas supply device 9. S base3 =130mm, diffusion safety factor l Using a value of 0.1, the safe avoidance distance is calculated. ΔS 3= S base3 + λD z3 =130mm + 0.1 × 73mm = 137mm. The inner diameter of the third gas supply device 9 is finally determined. D gas3 = D z3 + ΔS 3 = 73mm + 137mm = 210mm.

[0072] Argon gas with a flow rate of 15 L / min is supplied to the cooling and solidification path of the atomized particles within the third protection zone 13 through the third gas supply device, providing continuous atmosphere protection for the atomized particles during the long cooling and solidification process.

[0073] After the droplets are cooled and solidified under argon protection, they settle to the bottom of the collecting cylinder 15 to obtain a powder slurry.

[0074] Step S3: Dehydrate and dry the powder slurry obtained in step S2; After filtering out water, the obtained powder slurry was dried using a vacuum drying device at a temperature of 80℃ and a vacuum degree of not less than 1×10⁻⁶. -1 Pa, drying time is 3h, and the dried powder is sieved to obtain water atomized 310S stainless steel powder with different particle size ranges such as 60~100 mesh and 100~160 mesh.

[0075] Example 2 The preparation method of water-atomized 316L powder includes the following steps: Step S1: Melt and deoxidize the metal raw materials to obtain molten metal; 316L stainless steel raw materials, formulated from pure iron, pure nickel, ferrochrome alloy, and ferromolybdenum alloy, were placed in an induction melting furnace and heated and melted under nitrogen protection. After the raw materials were completely melted, ferrosilicon was added first, and the mixture was held at this temperature for 2 minutes to allow for a complete reaction. Then, calcium silicon was added. The total amount of deoxidizer added, based on silicon element, was 0.8 wt.% of the total mass of the raw materials. 50% of the total silicon added came from the calcium silicon, with the remainder coming from the ferrosilicon. The ferrosilicon contained 70 wt.% silicon, with the remainder being Fe and unavoidable impurities; the calcium silicon contained 60 wt.% silicon and 35 wt.% calcium, with the remainder being unavoidable impurities. After all the deoxidizer was added, the mixture was allowed to stand for 8 minutes to allow the slag to float to the surface. After thoroughly removing the slag, a clean, low-oxygen molten metal with a superheated temperature of 150°C was obtained.

[0076] Step S2: The molten metal obtained in step S1 is atomized under protective atmosphere to obtain a powder slurry; Step 2.1: Preparation of atomization environment: Introduce nitrogen into the atomization chamber to replace the air in the atomization chamber and obtain a low-oxygen atomization environment with an oxygen content ≤5 vol%. Step 2.2: Atomization and Powder Formation: Before atomization, adjust the position of the tundish crucible so that the center of its bottom drain is located on the central axis of the atomization system. Pour the molten 316L stainless steel obtained in step S1 into the tundish crucible 3, which has been preheated to 600℃. The molten liquid flows out through the 8mm diameter drain at the bottom of the crucible 3 and enters the atomization chamber, where it is atomized at an angle... α The high-pressure water jet, with a pressure of 10 MPa and a flow rate of 350 L / min, is broken into fine droplets by a 45° plate-flow V-shaped dual-focus atomizing nozzle. The casting operation is stopped when the remaining molten liquid in the melting furnace reaches 8% of the initial mass, through liquid level monitoring, to prevent deoxidation products from being carried into the atomization process.

[0077] The plate-flow V-shaped dual-focus atomizing nozzle used in this embodiment forms a high-pressure water jet. (Top view diagram follows) Figure 3 As shown. Among the theoretical intersection points formed by the geometric center plane of the plate-shaped water jet formed by the atomizing nozzle in the thickness direction and the oppositely arranged plate-shaped water jet in space extending downward along the spray direction, and the theoretical intersection point with the central axis of the atomizing system, the theoretical intersection point that is most upstream along the flow of molten metal (i.e., closest to the bottom of the leak outlet) is taken as the water atomization geometric focus 10 in this embodiment.

[0078] The horizontal distance between the center points of the outlets of the atomizing nozzles 6, which are oppositely positioned to form the geometric focus 10 of the water atomization, is formed. L=100mm, forming the geometric angle between the geometric center planes of the opposing water jets in the thickness direction, corresponding to the water atomization geometric focus 10 (the upstream theoretical intersection point). α =45°, according to the formula H =( L / 2) / tan( α / 2) Calculate the vertical distance below the plane where the water atomization geometric focus 10 of this embodiment is located at the water outlet of the atomizing nozzle 6. H On the central axis of the atomization system at approximately 121 mm.

[0079] Using the water atomization geometric focus 10 as the origin of the spatial coordinate system O(0,0,0), the central axis of the atomization system is... Z Establish a spatial rectangular coordinate system with the axis as the axis. The direction of the molten metal flow (from top to bottom) is used as the axis. Z Positive axis direction. During atomization, zoned atmosphere protection is implemented: First Protection Zone 11 (Liquid Flow Channel Zone): The continuous liquid flow channel area located between the outlet of the bottom leak 4 of the intermediate tundish crucible 3 and the geometric focus of water atomization 10 (i.e., z <0). With the central axis of the atomization system Z Centered on the axis, an annular first gas supply device 7 is set on the upper end face of the atomizing spray disk 5.

[0080] The first gas supply device 7 consists of an annular gas distribution pipe, a gas supply pipe connected to it, and a gas supply pipe located inside the gas distribution pipe and pointing radially. Z The shaft consists of jet holes. The inner diameter of the first gas supply device 7... D gas1 According to the diameter of the leak d nozzle =8mm and safe clearance ΔS 1 = 100mm, calculated and determined, that is D gas1 = d nozzle + ΔS 1 = 108 mm.

[0081] The first gas supply device 7 supplies nitrogen gas at a flow rate of 15 / min to the area around the molten metal flow 16 in the first protected zone, forming an inert atmosphere protective layer to prevent surface oxidation of the continuous flow before it breaks. Second Protection Zone 12 (Atomization and Breakup Zone): The spatial region located from the geometric focus of water atomization 10 to 250 mm below it, where the metal liquid flow 16 atomizes, breaks up, and initially forms micro-droplets (i.e., 0 mm ≤ z ≤250mm). With the central axis of the atomizing system as the guide. Z Centered on the axis, at a horizontal position H / 2 above the water atomization geometric focus 10 (i.e.,z =﹣ H An annular second gas supply device 8 is installed on the inner wall of the atomizing chamber at a distance of / 2=-60.5mm, with its vertical installation position measured on the horizontal plane where the center of the cross-section of its annular gas distribution pipeline is located.

[0082] The second gas supply device 8 consists of an annular gas distribution pipeline, a gas supply pipeline connected to it, and several gas guide pipes located inside the distribution pipeline and extending radially towards the center. The inner diameter of the second gas supply device 8... D gas2 Let be the diameter of the geometric circle formed by the center points of the end faces of all air outlets in the guide tubes. Based on the theoretical formula for the diameter of the atomizing cone... D z =2·| z |·tan( α / 2), calculate the vertical installation position of the second gas supply device 8. z = -60.5mm D z2 =50mm. According to the formula... D S 2= S base2 + λD z2 Set the basic safety distance for the second gas supply device 8. S base2 =100mm, diffusion safety factor l Using a value of 0.2, the safe avoidance distance is calculated. ΔS 2= S base2 + λD z2 =100mm + 0.2 × 50mm = 110mm. The inner diameter of the second gas supply device 8 is finally determined. D gas2 = D z2 + ΔS 2 = 50mm + 110mm = 160mm.

[0083] The second gas supply device 8 supplies nitrogen gas at a flow rate of 35 L / min to the atomization core area within the second protected area 12 where the molten metal flow is broken up by the high-pressure water jet. Utilizing the entrainment effect generated by the high-pressure water jet, the gas effectively enters the atomization core area, establishing an oxygen barrier around the micro-droplets formed at the moment the molten metal flow 16 is broken up and afterward, ensuring that newly generated high-temperature, high-surface-area molten metal droplets are isolated from oxygen. Third Protection Zone 13 (Cooling and Solidification Zone): The space area from the lower boundary of Second Protection Zone 12 to the bottom of Collection Cylinder 15 (i.e., z>250mm). With the central axis of the atomizing system as the guide. Z Centered on the axis, at a horizontal position 50mm above the lower boundary of the second protected area 12 (i.e. z On the inner wall of the atomizing chamber at a distance of 200mm, a ring-shaped third gas supply device 9 is installed, with its vertical installation position measured on the horizontal plane where the center of the cross-section of its ring-shaped gas distribution pipeline is located.

[0084] The third gas supply device 9 consists of an annular gas distribution pipeline, a gas supply pipeline connected to it, and several gas guide pipes located inside the distribution pipeline and extending radially towards the center. The inner diameter of the third gas supply device 9... D gas3 Let be the diameter of the geometric circle formed by the center points of the end faces of all air outlets in the guide tubes. Based on the theoretical formula for the diameter of the atomizing cone... D z =2·| z |·tan( α / 2), calculate the vertical installation position of the third gas supply device 9. z =200mm D z3 =166mm. According to the formula... ΔS 3= S base3 + λD z3 Set the basic safety distance for the third gas supply device 9. S base3 =130mm, diffusion safety factor l Using a value of 0.2, the safe avoidance distance is calculated. ΔS 3= S base3 + λD z3 =130mm + 0.2 × 166mm = 163mm. The inner diameter of the third gas supply device 9 is finally determined. D gas3 = D z3 + ΔS 3 = 166mm + 163mm = 329mm.

[0085] The third gas supply device supplies nitrogen gas at a flow rate of 25 L / min to the cooling and solidification path of the atomized particles within the third protection zone 13, providing continuous atmosphere protection for the atomized particles during the long cooling and solidification process.

[0086] After the droplets are cooled and solidified under nitrogen protection, they settle to the bottom of the collecting cylinder 15 to obtain a powder slurry.

[0087] Step S3: Dehydrate and dry the powder slurry obtained in step S2; After filtering out water, the obtained powder slurry was dried using a vacuum drying device at a temperature of 120℃ and a vacuum degree of not less than 1×10⁻⁶. -1 Pa, drying time is 2h, and the dried powder is sieved to obtain water atomized 316L stainless steel powder with different particle size ranges such as 60~100 mesh and 100~160 mesh.

[0088] Example 3 A method for preparing water-atomized iron-aluminum alloy powder includes the following steps: Step S1: Melt and deoxidize the metal raw materials to obtain molten metal; A ferroaluminum alloy raw material (20 wt.% Al, 6 wt.% Cr, balance Fe and unavoidable impurities) prepared from pure iron, pure aluminum, and ferrochrome alloy was placed in an induction melting furnace and heated and melted under argon protection. After the raw material was completely melted, ferrosilicon was added first, and the mixture was kept at this temperature for 1 minute to allow for a complete reaction. Then, calcium silicon was added. The total amount of deoxidizer added, based on Si element, was 1.0 wt.% of the total mass of the raw material. Of this, 40% of the Si in the calcium silicon came from the ferrosilicon, with the balance coming from the ferrosilicon. The ferrosilicon contained 75 wt.% silicon, with the balance being Fe and unavoidable impurities; the calcium silicon contained 60 wt.% silicon and 35 wt.% calcium, with the balance being unavoidable impurities. After all the deoxidizer was added, the mixture was allowed to stand for 7 minutes to allow the slag to float to the surface. After thoroughly removing the slag, a clean, low-oxygen molten metal with a superheated temperature of 300℃ was obtained.

[0089] Step S2: The molten metal obtained in step S1 is atomized under protective atmosphere to obtain a powder slurry; Step 2.1: Preparation of atomization environment: Argon gas is introduced into the atomization chamber to replace the air in the atomization chamber and obtain a low-oxygen atomization environment with an oxygen content ≤5 vol%. Step 2.2: Atomization and Powder Formation: Before atomization, adjust the position of the tundish crucible so that the center of its bottom drain is located on the central axis of the atomization system. Pour the molten iron and aluminum metal obtained in step S1 into the tundish crucible 3, which has been preheated to 700°C. The molten metal flows out through the 8mm diameter drain at the bottom of the crucible 3 and enters the atomization chamber, where it is atomized at an angle... α A high-pressure water jet with a pressure of 12 MPa and a flow rate of 250 L / min, generated by a 45° linear flow ring orifice type single-focus atomizing nozzle, is broken into fine droplets. The casting operation is stopped when the remaining molten liquid in the melting furnace reaches 8% of the initial mass, through liquid level monitoring, to prevent deoxidation products from being carried into the atomization process.

[0090] The linear flow ring orifice type single-focus atomizing nozzle used in this embodiment forms a high-pressure water jet. (Top view schematic diagram follows) Figure 2As shown. The theoretical intersection point where the central axis of the linear water jet formed by the atomizing nozzle extends along the spray direction and intersects with the central axis of the atomizing system where the freely falling molten metal 16 is located is taken as the water atomization geometric focus 10 in this embodiment.

[0091] Diameter of the distribution circle at the center point of the atomizing nozzle 6 outlet L =100mm, forming the apex angle of the theoretical cone formed by the central axes of each linear water jet, corresponding to the geometric focus 10 of the water atomization, i.e., the atomization angle. α =45°, according to the formula H =( L / 2) / tan( α / 2) Calculate the vertical distance below the plane where the water atomization geometric focus 10 of this embodiment is located at the water outlet of the atomizing nozzle 6. H On the central axis of the atomization system at approximately 121 mm.

[0092] Using the water atomization geometric focus 10 as the origin of the spatial coordinate system O(0,0,0), the central axis of the atomization system is... Z Establish a spatial rectangular coordinate system with the axis as the axis. The direction of the molten metal flow (from top to bottom) is used as the axis. Z Positive axis direction. During atomization, zoned atmosphere protection is implemented: First Protection Zone 11 (Liquid Flow Channel Zone): The continuous liquid flow channel area located between the outlet of the bottom leak 4 of the intermediate tundish crucible 3 and the geometric focus of water atomization 10 (i.e., z <0). With the central axis of the atomization system Z Centered on the axis, an annular first gas supply device 7 is set on the upper end face of the atomizing spray disk 5.

[0093] The first gas supply device 7 consists of an annular gas distribution pipe, a gas supply pipe connected to it, and a gas supply pipe located inside the gas distribution pipe and pointing radially. Z The shaft consists of jet holes. The inner diameter of the first gas supply device 7... D gas1 According to the diameter of the leak d nozzle =8mm and safe clearance ΔS 1 = 120mm, calculated and determined, that is D gas1 = d nozzle + ΔS 1 = 128mm.

[0094] Argon gas with a flow rate of 10 L / min is supplied to the metal molten flow 16 in the first protected area through the first gas supply device 7 to form an inert atmosphere protective layer and prevent the continuous liquid flow from undergoing surface oxidation before it breaks. Second Protection Zone 12 (Atomization and Breakup Zone): The spatial region located from the geometric focus of water atomization 10 to 150 mm below it, where the metal liquid flow 16 atomizes and breaks up, and where fine droplets initially form (i.e., 0 mm ≤ z ≤150mm). With the central axis of the atomization system as the guide. Z Centered on the axis, above the water atomization geometric focus 10 H / 2 horizontal position (i.e.) z =﹣ H An annular second gas supply device 8 is installed on the inner wall of the atomizing chamber at a distance of / 2=-60.5mm, with its vertical installation position measured on the horizontal plane where the center of the cross-section of its annular gas distribution pipeline is located.

[0095] The second gas supply device 8 consists of an annular gas distribution pipeline, a gas supply pipeline connected to it, and several gas guide pipes located inside the distribution pipeline and extending radially towards the center. The inner diameter of the second gas supply device 8... D gas2 Let be the diameter of the geometric circle formed by the center points of the end faces of all air outlets in the guide tubes. Based on the theoretical formula for the diameter of the atomizing cone... D z =2·| z |·tan( α / 2), calculate the vertical installation position of the second gas supply device 8. z =60.5mm D z2 =50mm. According to the formula... ΔS 2= S base2 + λD z2 Set the basic safety distance for the second gas supply device 8. S base2 =100mm, diffusion safety factor l Using a value of 0.3, the safe avoidance distance is calculated. ΔS 2= S base2 + λD z2 =100mm + 0.3 × 50mm = 115mm. The inner diameter of the second gas supply device 8 is finally determined. D gas2 = D z2 + ΔS 2 = 50mm + 115mm = 165mm.

[0096] Argon gas with a flow rate of 40L / min is supplied to the atomization core area of ​​the metal liquid flow broken by the high-pressure water jet in the second protection zone 12 through the second gas supply device 8. The entrainment effect generated by the high-pressure water jet allows the gas to effectively enter the atomization core area and establishes an oxygen barrier around the micro-droplets formed at the moment the metal liquid flow 16 is broken and after the breakage, ensuring that the newly generated high-temperature, high specific surface area metal droplets are isolated from oxygen. Third Protection Zone 13 (Cooling and Solidification Zone): The space from the lower boundary of Second Protection Zone 12 to the bottom of the collecting cylinder (i.e., z >150mm). With the central axis of the atomizing system as the guide. Z Centered on the axis, at a horizontal position 50mm above the lower boundary of the second protected area 12 (i.e. z On the inner wall of the atomizing chamber at a distance of 100mm, a ring-shaped third gas supply device 9 is installed, with its vertical installation position measured on the horizontal plane where the center of the cross-section of its ring-shaped gas distribution pipeline is located.

[0097] The third gas supply device 9 consists of an annular gas distribution pipeline, a gas supply pipeline connected to it, and several gas guide pipes located inside the distribution pipeline and extending radially towards the center. The inner diameter of the third gas supply device 9... D gas3 Let be the diameter of the geometric circle formed by the center points of the end faces of all air outlets in the guide tubes. Based on the theoretical formula for the diameter of the atomizing cone... D z =2·| z |·tan( α / 2), calculate the vertical installation position of the third gas supply device 9. z =100mm D z3 =83mm. According to the formula... ΔS 3= S base3 + λD z3 Set the basic safety distance for the third gas supply device 9. S base3 =130mm, diffusion safety factor l Using a value of 0.3, the safe avoidance distance is calculated. ΔS 3= S base3 + λD z3 =130mm + 0.3 × 83mm = 155mm. The inner diameter of the third gas supply device 9 is finally determined. D gas3 = D z3 + ΔS 3 = 83mm + 155mm = 238mm.

[0098] Argon gas with a flow rate of 25 L / min is supplied to the cooling and solidification path of the atomized particles within the third protection zone 13 through the third gas supply device, providing continuous atmosphere protection for the atomized particles during the long cooling and solidification process.

[0099] After the droplets are cooled and solidified under argon protection, they settle to the bottom of the collecting cylinder 15 to obtain a powder slurry.

[0100] Step S3: Dehydrate and dry the powder slurry obtained in step S2; After the obtained powder slurry is filtered to remove water, it is dried using a vacuum drying device at a temperature of 100℃ and a vacuum degree of not less than 1×10⁻⁶. -1 Pa, drying time is 2.5h, and the dried powder is sieved to obtain water atomized iron-aluminum alloy powder with different particle size ranges such as 40~150 mesh and 150~300 mesh.

[0101] Example 4 A method for preparing water-atomized iron-aluminum alloy powder includes the following steps: Step S1: Melt and deoxidize the metal raw materials to obtain molten metal; A ferroaluminum alloy raw material (15 wt.% Al, 5 wt.% Cr, balance Fe and unavoidable impurities) composed of pure iron, pure aluminum, and ferrochrome was placed in an induction melting furnace and heated and melted under argon protection. After the raw material was completely melted, ferrosilicon was added first, and the mixture was kept at this temperature for 2 minutes to allow for a complete reaction. Then, calcium silicon was added. The total amount of deoxidizer added, based on Si element, was 0.8 wt.% of the total mass of the raw material. Of this, Si in the calcium silicon accounted for 40% of the total Si added, with the balance coming from the ferrosilicon. The ferrosilicon contained 73 wt.% silicon, with the balance being Fe and unavoidable impurities; the calcium silicon contained 62 wt.% silicon and 33 wt.% calcium, with the balance being unavoidable impurities. After all the deoxidizer was added, the mixture was allowed to stand for 6 minutes to allow the slag to float to the surface. After thoroughly removing the slag, a clean, low-oxygen molten metal with a superheated temperature of 250°C was obtained.

[0102] Step S2: The molten metal obtained in step S1 is atomized under protective atmosphere to obtain a powder slurry; Step 2.1: Preparation of atomization environment: Argon gas is introduced into the atomization chamber to replace the air in the atomization chamber and obtain a low-oxygen atomization environment with an oxygen content ≤5 vol%. Step 2.2: Atomization and Powder Formation: Before atomization, adjust the position of the tundish crucible so that the center of its bottom drain is located on the central axis of the atomization system. Pour the molten iron and aluminum metal obtained in step S1 into the tundish crucible 3, which has been preheated to 800°C. The molten metal flows out through the 9mm diameter drain at the bottom of the crucible 3 and enters the atomization chamber, where it is atomized at an angle... αA high-pressure water jet with a pressure of 13.5 MPa and a flow rate of 270 L / min, generated by a 40° plate-shaped V-shaped dual-focus atomizing nozzle, is broken into fine droplets. The casting operation is stopped when the remaining molten liquid in the melting furnace reaches 7% of the initial mass, as monitored by liquid level, to prevent deoxidation products from being carried into the atomization process.

[0103] The plate-flow V-shaped dual-focus atomizing nozzle used in this embodiment forms a high-pressure water jet. (Top view diagram follows) Figure 3 As shown. Among the theoretical intersection points formed by the geometric center plane of the plate-shaped water jet formed by the atomizing nozzle in the thickness direction and the oppositely arranged plate-shaped water jet in space extending downward along the spray direction, and the theoretical intersection point with the central axis of the atomizing system, the theoretical intersection point that is most upstream along the flow of molten metal (i.e., closest to the bottom of the leak outlet) is taken as the water atomization geometric focus 10 in this embodiment.

[0104] The horizontal distance between the center points of the outlets of the atomizing nozzles 6, which are oppositely positioned to form the geometric focus 10 of the water atomization, is formed. L =90mm, forming the geometric angle between the geometric center planes of the opposing water jets in the thickness direction, corresponding to the water atomization geometric focus 10 (the most upstream theoretical intersection point). α =40°, according to the formula H =( L / 2) / tan( α / 2) Calculate the vertical distance below the plane where the water atomization geometric focus 10 of this embodiment is located at the water outlet of the atomizing nozzle 6. H On the central axis of the atomization system at approximately 124 mm.

[0105] Using the water atomization geometric focus 10 as the origin of the spatial coordinate system O(0,0,0), the central axis of the atomization system is... Z Establish a spatial rectangular coordinate system with the axis as the axis. The direction of the molten metal flow (from top to bottom) is used as the axis. Z Positive axis direction. During atomization, zoned atmosphere protection is implemented: First Protection Zone 11 (Liquid Flow Channel Zone): The continuous liquid flow channel area located between the outlet of the bottom leak 4 of the intermediate tundish crucible 3 and the geometric focus of water atomization 10 (i.e., z <0). With the central axis of the atomization system Z Centered on the axis, an annular first gas supply device 7 is set on the upper end face of the atomizing spray disk 5.

[0106] The first gas supply device 7 consists of an annular gas distribution pipe, a gas supply pipe connected to it, and a gas supply pipe located inside the gas distribution pipe and pointing radially. Z The shaft consists of jet holes. The inner diameter of the first gas supply device 7... D gas1 According to the diameter of the leakd nozzle =9mm and safe clearance ΔS 1 = 100mm, calculated and determined, that is D gas1 = d nozzle + ΔS 1 = 109 mm.

[0107] Argon gas with a flow rate of 13 / min is supplied to the metal liquid flow 16 in the first protected area through the first gas supply device 7 to form an inert atmosphere protective layer and prevent the continuous liquid flow from undergoing surface oxidation before it breaks. Second Protection Zone 12 (Atomization Breakup Zone): The spatial region located between the water atomization geometric focus 10 and 200 mm below it, encompassing the atomization breakup of the molten metal flow 16 and the initial formation of fine droplets (i.e., 0 mm ≤ z ≤200mm). With the central axis of the atomizing system as the guide. Z Centered on the axis, at the horizontal position of the water atomization geometric focus 10 ( z On the inner wall of the atomizing chamber at 0mm, an annular second gas supply device 8 is installed, with its vertical installation position measured on the horizontal plane where the center of the cross-section of its annular gas distribution pipeline is located.

[0108] The second gas supply device 8 consists of an annular gas distribution pipeline, a gas supply pipeline connected to it, and several gas guide pipes located inside the distribution pipeline and extending radially towards the center. The inner diameter of the second gas supply device 8... D gas2 Let be the diameter of the geometric circle formed by the center points of the end faces of all air outlets in the guide tubes. Based on the theoretical formula for the diameter of the atomizing cone... D z =2·| z |·tan( α / 2), calculate the vertical installation position of the second gas supply device 8. z =0mm D z2 =0mm. According to the formula... ΔS 2= S base2 + λD z2 Set the basic safety distance for the second gas supply device 8. S base2 =100mm, diffusion safety factor l Using a value of 0.1, the safe avoidance distance is calculated. ΔS 2= S base2 + λD z2=100mm + 0.1 × 0mm = 100mm. The inner diameter of the second gas supply device 8 is thus determined. D gas2 = D z2 + ΔS 2 = 0mm + 100mm = 100mm.

[0109] Argon gas at a flow rate of 35 L / min is supplied to the atomization core area within the second protected zone 12, where the molten metal flow is broken up by a high-pressure water jet, through the second gas supply device 8. Utilizing the entrainment effect generated by the high-pressure water jet, the gas effectively enters the atomization core area and establishes an oxygen barrier around the micro-droplets formed at the moment the molten metal flow 16 is broken up and afterward, ensuring that the newly generated high-surface-area molten metal droplets are isolated from oxygen. Third Protection Zone 13 (Cooling and Solidification Zone): The space from the lower boundary of Second Protection Zone 12 to the bottom of the collecting cylinder (i.e., z >200mm). With the central axis of the atomizing system as the guide. Z Centered on the axis, two layers of annular third gas supply devices 9 are installed on the inner wall of the atomizing chamber: the top layer is located 50 mm above the lower boundary of the second protection zone 12 at a horizontal position (i.e., z = 150 mm), and the second layer is located 200 mm directly below the first layer at a horizontal position (i.e., z = 350 mm). The vertical installation position is measured based on the horizontal plane where the center of the cross-section of the annular gas distribution pipeline is located.

[0110] The third gas supply device 9 consists of an annular gas distribution pipeline, a gas supply pipeline connected to it, and several gas guide pipes located inside the distribution pipeline and extending radially towards the center. The inner diameter of the third gas supply device 9... D gas3 Let be the diameter of the geometric circle formed by the center points of the end faces of all air outlets in the guide tubes. Based on the theoretical formula for the diameter of the atomizing cone... D z =2·| z |·tan( α / 2), calculate the top layer ( z =150mm) and the second layer ( z =350mm) The conical diameter at the vertical installation position of the third gas supply device 9 D z The calculation yielded the top-level third gas supply device 9. D z3 1 =109mm, the second layer third gas supply device 9 D z3 2 =255mm. According to the formula... ΔS 3= Sbase3 + λD z3 Set the basic safety distance for the third gas supply device 9. S base3 =130mm. The diffusion safety factor of the top-level third gas supply device 9 is taken as 0.2, and its safe avoidance distance is calculated. ΔS 3 1 = S base3 + λD z3 1 =130mm + 0.2 × 10⁹ mm = 152mm. The diffusion safety factor of the second-layer third gas supply device 9. l Using a value of 0.3, the safe avoidance distance is calculated. ΔS 3 2 = S base3 + λD z3 2 =130mm + 0.3 × 255mm = 206mm. The final inner diameter of the top-level third gas supply device 9 is determined. D gas3 1 = D z3 1 + ΔS 3 1 =109mm + 152mm = 261mm, the inner diameter of the third gas supply device 9 in the second layer. D gas3 2 = D z3 2 + ΔS 3 2 =255mm + 206mm = 461mm.

[0111] Argon gas with flow rates of 25 L / min and 20 L / min is supplied to the cooling and solidification path of the atomized particles in the third protected area 13 through the third gas supply device of the top and second layers, respectively, to provide continuous atmosphere protection for the atomized particles during the long cooling and solidification process. After the droplets are cooled and solidified under argon protection, they settle to the bottom of the collecting cylinder 15 to obtain a powder slurry.

[0112] Step S3: Dehydrate and dry the powder slurry obtained in step S2; After filtering out water, the obtained powder slurry was dried using a vacuum drying device at a temperature of 120℃ and a vacuum degree of not less than 1×10⁻⁶. -1Pa, drying time is 2h, and the dried powder is sieved to obtain water atomized iron-aluminum alloy powder with different particle size ranges such as 40~150 mesh and 150~300 mesh.

[0113] Example 5 A method for preparing water-atomized iron-aluminum alloy powder includes the following steps: Step S1: Melt and deoxidize the metal raw materials to obtain molten metal; A ferroaluminum alloy raw material (10 wt.% Al, 4 wt.% Cr, balance Fe and unavoidable impurities) composed of pure iron, pure aluminum, and ferrochrome was placed in an induction melting furnace and heated and melted under nitrogen protection. After the raw material was completely melted, ferrosilicon was added first, and the mixture was kept at this temperature for 3 minutes to allow for a complete reaction. Then, calcium silicon was added. The total amount of deoxidizer added, based on Si element, was 0.6 wt.% of the total mass of the raw material. Of this, Si in the calcium silicon accounted for 35% of the total Si added, with the balance coming from the ferrosilicon. The ferrosilicon contained 70 wt.% silicon, with the balance being Fe and unavoidable impurities; the calcium silicon contained 65 wt.% silicon and 30 wt.% calcium, with the balance being unavoidable impurities. After all the deoxidizer was added, the mixture was allowed to stand for 5 minutes to allow the slag to float to the surface. After thoroughly removing the slag, a clean, low-oxygen molten metal with a superheated temperature of 200°C was obtained.

[0114] Step S2: The molten metal obtained in step S1 is atomized under protective atmosphere to obtain a powder slurry; Step 2.1: Preparation of atomization environment: Introduce nitrogen into the atomization chamber to replace the air in the atomization chamber and obtain a low-oxygen atomization environment with an oxygen content ≤5 vol%. Step 2.2: Atomization and Powder Formation: Before atomization, adjust the position of the tundish crucible so that the center of its bottom drain is located on the central axis of the atomization system. Pour the molten iron and aluminum metal obtained in step S1 into the tundish crucible 3, which has been preheated to 600°C. The molten metal flows out through the 10mm diameter drain at the bottom of the crucible 3 and enters the atomization chamber, where it is atomized at an angle... α A high-pressure water jet with a pressure of 15 MPa and a flow rate of 300 L / min, generated by a 35° plate-shaped V-shaped dual-focus atomizing nozzle, is broken into fine droplets. The casting operation is stopped when the remaining molten liquid in the melting furnace is approximately 6% of the initial mass, as monitored by liquid level monitoring, to prevent deoxidation products from being carried into the atomization process.

[0115] The plate-flow V-shaped dual-focus atomizing nozzle used in this embodiment forms a high-pressure water jet. (Top view diagram follows) Figure 3As shown. Among the theoretical intersection points formed by the geometric center plane of the plate-shaped water jet stream formed by the atomizing nozzle in the thickness direction and the oppositely arranged plate-shaped water jet stream extending downward in space along the spray direction and the central axis of the atomizing system, the theoretical intersection point that is most upstream along the flow of molten metal (i.e., closest to the bottom of the leak outlet) is taken as the water atomization geometric focus 10 in this embodiment.

[0116] The horizontal distance between the center points of the outlets of the atomizing nozzles 6, which are oppositely positioned to form the geometric focus 10 of the water atomization, is formed. L =80mm, forming the geometric angle between the geometric center planes of the opposing water jets in the thickness direction, corresponding to the water atomization geometric focus 10 (the most upstream theoretical intersection point). α =35°, according to the formula H =( L / 2) / tan( α / 2) Calculate the vertical distance below the plane where the water atomization geometric focus 10 of this embodiment is located at the water outlet of the atomizing nozzle 6. H On the central axis of the atomization system at approximately 127mm.

[0117] Using the water atomization geometric focus 10 as the origin of the spatial coordinate system O(0,0,0), the central axis of the atomization system is... Z Establish a spatial rectangular coordinate system with the axis as the axis. The direction of the molten metal flow (from top to bottom) is used as the axis. Z Positive axis direction. During atomization, zoned atmosphere protection is implemented: First Protection Zone 11 (Liquid Flow Channel Zone): The continuous liquid flow channel area located between the outlet of the bottom leak 4 of the intermediate tundish crucible 3 and the geometric focus of water atomization 10 (i.e., z <0). With the central axis of the atomization system Z Centered on the axis, an annular first gas supply device 7 is set on the upper end face of the atomizing spray disk 5.

[0118] The first gas supply device 7 consists of an annular gas distribution pipe, a gas supply pipe connected to it, and a gas supply pipe located inside the gas distribution pipe and pointing radially. Z The shaft consists of jet holes. The inner diameter of the first gas supply device 7... D gas1 According to the diameter of the leak d nozzle =10mm and safe clearance ΔS 1 = 80mm, calculated and determined, that is D gas1 = d nozzle + ΔS 1 = 90mm.

[0119] The first gas supply device 7 supplies nitrogen gas at a flow rate of 15 / min to the area around the molten metal flow 16 in the first protected zone, forming an inert atmosphere protective layer to prevent surface oxidation of the continuous flow before it breaks. Second Protection Zone 12 (Atomization Breakup Zone): The spatial region located between the water atomization geometric focus 10 and 250 mm below it, where the metal liquid flow 16 atomizes, breaks up, and initially forms micro-droplets (i.e., 0 mm ≤ z ≤250mm). With the central axis of the atomizing system as the guide. Z Centered on the axis, at a horizontal position 50mm below the water atomization geometric focus 10 (i.e., z An annular second gas supply device 8 is installed on the inner wall of the atomizing chamber at a distance of 50 mm. Its vertical installation position is measured with the horizontal plane where the center of the cross-section of its annular gas distribution pipeline is located as the reference.

[0120] The second gas supply device 8 consists of an annular gas distribution pipeline, a gas supply pipeline connected to it, and several gas guide pipes located inside the distribution pipeline and extending radially towards the center. The inner diameter of the second gas supply device 8... D gas2 The diameter of the geometric circle formed by the center points of the end faces of all the gas outlets of the gas delivery pipes. Based on the vertical installation position of the second gas supply device 8. z Formula for the theoretical atomizing cone diameter at 50mm D z =2·| z |·tan( α / 2), calculated to D z2 =32mm. According to the formula... D S 2= S base2 + λD z2 Set the basic safety distance for the second gas supply device 8. S base2 =100mm, diffusion safety factor l Using a value of 0.1, the safe avoidance distance is calculated. ΔS 2= S base2 + λD z2 =100mm + 0.1 × 32mm = 103mm. The inner diameter of the second gas supply device 8 is finally determined. D gas2 = D z2 + ΔS 2 = 32mm + 103mm = 135mm.

[0121] The second gas supply device 8 supplies nitrogen gas at a flow rate of 30 L / min to the atomization core area within the second protected area 12 where the molten metal flow is broken up by the high-pressure water jet. Utilizing the entrainment effect generated by the high-pressure water jet, the gas effectively enters the atomization core area, establishing an oxygen barrier around the micro-droplets formed at the moment the molten metal flow 16 is broken up and afterward, ensuring that the newly generated high-temperature, high-specific-surface-area molten metal droplets are isolated from oxygen. Third Protection Zone 13 (Cooling and Solidification Zone): The space from the lower boundary of Second Protection Zone 12 to the bottom of the collecting cylinder (i.e., z >250mm). With the central axis of the atomizing system as the guide. Z Centered on the axis, two layers of annular third gas supply devices 9 are installed on the inner wall of the atomization chamber: the top layer is located 50mm above the lower boundary of the second protective zone 12 at a horizontal position (i.e., z At a position of 200mm, the second layer is located 150mm directly below the first layer (i.e., =200mm), and the third layer is located at a horizontal position of 150mm directly below the first layer (i.e., =200mm). z =350mm), the third layer is located 300mm directly below the first layer (i.e., =350mm). z At a location of 500mm, its vertical installation position is measured using the horizontal plane where the center of the cross-section of its annular gas distribution pipeline is located.

[0122] The third gas supply device 9 consists of an annular gas distribution pipeline, a gas supply pipeline connected to it, and several gas guide pipes located inside the distribution pipeline and extending radially towards the center. The inner diameter of the third gas supply device 9... D gas3 Let be the diameter of the geometric circle formed by the center points of the end faces of all air outlets in the guide tubes. Based on the theoretical formula for the diameter of the atomizing cone... D z =2·| z |·tan( α / 2), calculate the top layer ( z =200mm), second layer ( z =350mm) and the third layer ( z =500mm) The diameter of the conical surface at the vertical installation position of the third gas supply device 9 is calculated to obtain the top-level third gas supply device 9. D z3 1 =126mm, the second layer third gas supply device 9 D z3 2 =221mm, third layer third gas supply device 9 D z3 3 =315mm. According to the formula... D S 3= S base3 + λD z3 Set the basic safety distance for the third gas supply device 9. S base3 =130mm. Diffusion safety factor of the top-level third gas supply device 9. l Using a value of 0.1, the safe avoidance distance is calculated. ΔS 3 1 = S base3 + λD z3 1 =130mm + 0.1 × 126mm = 143mm. The diffusion safety factor of the second-layer third gas supply device 9. l Using a value of 0.2, the safe avoidance distance is calculated. ΔS 3 2 = S base3 + λD z3 2 =130mm + 0.2 × 221mm = 174mm. The diffusion safety factor of the third gas supply device 9 in the third layer. l Using a value of 0.3, the safe avoidance distance is calculated. ΔS 3 3 = S base3 + λD z3 3 =130mm + 0.3 × 315mm = 225mm. The final inner diameter of the top-level third gas supply device 9 is determined. D gas3 1 = D z3 1 + ΔS 3 1 =126mm + 143mm = 269mm; Inner diameter of the second layer third gas supply device 9 D gas3 2 = D z3 2 + ΔS 3 2 =221mm + 174mm = 395mm; Inner diameter of the third gas supply device 9 in the third layer D gas3 3 = D z3 3 + ΔS 3 3 =315mm + 225mm = 540mm.

[0123] The third gas supply devices in the top, second, and third layers supply nitrogen gas at flow rates of 25 L / min, 20 L / min, and 15 L / min respectively to the cooling and solidification path of the atomized particles in the third protected area 13, providing continuous atmosphere protection for the atomized particles during the long cooling and solidification process.

[0124] After the droplets are cooled and solidified under nitrogen protection, they settle to the bottom of the collecting cylinder 15 to obtain a powder slurry.

[0125] Step S3: Dehydrate and dry the powder slurry obtained in step S2; After filtering out water, the obtained powder slurry was dried using a vacuum drying device at a temperature of 80℃ and a vacuum degree of not less than 1×10⁻⁶. -1 Pa, drying time is 3h, and the dried powder is sieved to obtain water atomized iron-aluminum alloy powder with different particle size ranges such as 40~150 mesh and 150~300 mesh.

[0126] Table 1 lists the oxygen content and bulk density of the metal powders with different particle size ranges prepared in Examples 1-5. Figure 8 These are microscopic morphology photographs of 100-160 mesh 316L stainless steel powder from Example 2. Figure 9 These are microscopic morphology photographs of the 40-150 mesh iron-aluminum alloy powders used in Example 4. As can be seen from the images, the powders are all highly irregular in shape, indicating that they have good formability.

[0127] Table 1. Oxygen content and bulk density of metal powders with different particle size ranges prepared in Examples 1-5

[0128] Compared to Example 1, Example 2 uses higher atomizing water pressure to match a larger orifice diameter to increase the cooling rate, and is supplemented with a higher inert gas flow rate and deoxidizer content to adapt its process conditions, thereby further reducing the loose packing density and oxygen content of the powder. In Examples 3-5, to overcome the high viscosity and high oxidation risk introduced by aluminum in the iron-aluminum alloy, a larger orifice diameter and higher atomizing water pressure and protective atmosphere flow rate were used, resulting in iron-aluminum alloy powder with lower oxygen content and loose packing density.

[0129] The 100-160 mesh 316L stainless steel powder obtained in Example 2 and the 40-150 mesh iron-aluminum alloy powder obtained in Example 4 were pressed into shape and then sintered at 1300℃ and 1000℃ for 3 hours respectively under a hydrogen atmosphere to obtain a porous metal filter with high porosity and uniform pore size. This filter exhibits good permeability and mechanical strength in high-temperature filtration applications.

[0130] Example 6 The preparation method of water-atomized 310S powder includes the following steps: Step S1: Melt and deoxidize the metal raw materials to obtain molten metal; 310S stainless steel raw material, formulated from pure iron, pure nickel, and ferrochrome alloy, was placed in an induction melting furnace and heated and melted under argon protection. After the raw material was completely melted, ferrosilicon was added first, and the mixture was held at this temperature for 3 minutes to allow for a complete reaction. Then, calcium silicon was added. The total amount of deoxidizer added, based on Si element, was 1.0 wt.% of the total mass of the raw material. Of this, Si in the calcium silicon accounted for 30 wt.% of the total Si added, with the remainder coming from the ferrosilicon. The ferrosilicon contained 75 wt.% silicon, with the remainder being Fe and unavoidable impurities; the calcium silicon contained 65 wt.% silicon and 30 wt.% calcium, with the remainder being unavoidable impurities. After all the deoxidizer was added, the mixture was allowed to stand for 6 minutes to allow the slag to float to the surface. After thoroughly removing the slag, a clean, low-oxygen molten metal with a superheated temperature of 200°C was obtained.

[0131] Step S2: The molten metal obtained in step S1 is atomized under protective atmosphere to obtain a powder slurry; Step 2.1: Preparation of atomization environment: Argon gas is introduced into the atomization chamber to replace the air in the atomization chamber and obtain a low-oxygen atomization environment with an oxygen content ≤5 vol%. Step 2.2: Atomization and Powder Formation: Before atomization, adjust the position of the tundish crucible so that the center of its bottom drain is located on the central axis of the atomization system. Pour the molten 310S stainless steel obtained in step S1 into the tundish crucible 3, which has been preheated to 700℃. The molten liquid flows out through the 7mm diameter drain at the bottom of the crucible 3 and enters the atomization chamber, where it is atomized at an angle... α A high-pressure water jet with a pressure of 9 MPa and a flow rate of 325 L / min, generated by a 40° linear flow ring orifice type single-focus atomizing nozzle, is broken into fine droplets. The casting operation is stopped when the remaining molten liquid in the melting furnace reaches 5% of the initial mass, through liquid level monitoring, to prevent deoxidation products from being carried into the atomization process.

[0132] The linear flow ring orifice type single-focus atomizing nozzle used in this embodiment forms a high-pressure water jet. (Top view schematic diagram follows) Figure 2 As shown. The theoretical intersection point where the central axis of the linear water jet formed by the atomizing nozzle extends along the spray direction and intersects with the central axis of the atomizing system where the freely falling molten metal 16 is located is taken as the water atomization geometric focus 10 in this embodiment.

[0133] Diameter of the distribution circle at the center point of the atomizing nozzle 6 outlet L =100mm, forming the apex angle of the theoretical cone formed by the central axes of all linear water jets corresponding to the geometric focus of water atomization, i.e., the atomization angle. α=45°, according to the formula H =( L Calculated using / 2) / tan(α / 2), the vertical distance below the plane where the water atomization geometric focus 10 of this embodiment is located at the water outlet of the atomizing nozzle 6 is obtained. H On the central axis of the atomization system at approximately 121 mm.

[0134] Using the water atomization geometric focus 10 as the origin of the spatial coordinate system O(0,0,0), the central axis of the atomization system is... Z Establish a spatial rectangular coordinate system with the axis as the axis. The direction of the molten metal flow (from top to bottom) is used as the axis. Z Positive axis direction. During atomization, zoned atmosphere protection is implemented: First protected zone 11 (liquid flow channel area): The continuous liquid flow channel area located between the outlet of the bottom leak 4 of the intermediate ladle crucible 3 and the geometric focus of water atomization 10 (i.e., z <0). With the central axis of the atomization system Z Centered on the axis, an annular first gas supply device 7 is set on the upper end face of the atomizing spray disk 5.

[0135] The first gas supply device 7 consists of an annular gas distribution pipe, a gas supply pipe connected to it, and a gas supply pipe located inside the gas distribution pipe and pointing radially. Z The shaft consists of jet holes. The inner diameter of the first gas supply device 7... D gas1 According to the diameter of the leak d nozzle =7mm and safe clearance ΔS 1 = 110mm, calculated and determined, that is D gas1 = d nozzle + ΔS 1 = 117mm.

[0136] Argon gas with a flow rate of 12.5 L / min is supplied to the metal liquid flow 16 in the first protected area through the first gas supply device 7 to form an inert atmosphere protective layer and prevent the continuous liquid flow from undergoing surface oxidation before it breaks. Second Protection Zone 12 (Atomization and Breakup Zone): The spatial region located from the geometric focus of water atomization 10 to 150 mm below it, where the metal liquid flow 16 atomizes and breaks up, and where fine droplets initially form (i.e., 0 mm ≤ z ≤150mm). With the central axis of the atomization system as the guide. Z Centered on the axis, above the water atomization geometric focus 10 H / 2 horizontal position (i.e.) z =﹣ HAn annular second gas supply device 8 is installed on the inner wall of the atomizing chamber at a distance of / 2=-60.5mm, with its vertical installation position measured on the horizontal plane where the center of the cross-section of its annular gas distribution pipeline is located.

[0137] The second gas supply device 8 consists of an annular gas distribution pipeline, a gas supply pipeline connected to it, and several gas guide pipes located inside the distribution pipeline and extending radially towards the center. The inner diameter of the second gas supply device 8... D gas2 Let be the diameter of the geometric circle formed by the center points of the end faces of all air outlets in the guide tubes. Based on the theoretical formula for the diameter of the atomizing cone... D z =2·| z |·tan( α / 2), calculate the vertical installation position of the second gas supply device 8. z = -60.5mm D z2 =50mm. According to the formula... D S 2= S base2 + λD z2 Set the basic safety distance for the second gas supply device 8. S base2 =100mm, diffusion safety factor l Using a value of 0.1, the safe avoidance distance is calculated. ΔS 2= S base2 + λD z2 =100mm + 0.1 × 50mm = 105mm. The inner diameter of the second gas supply device 8 is thus determined. D gas2 = D z2 + ΔS 2 = 50mm + 105mm = 155mm.

[0138] Argon gas at a flow rate of 30 L / min is supplied to the atomization core area within the second protected area 12, where the molten metal flow is broken up by a high-pressure water jet, through the second gas supply device 8. The atomization core area, where the molten metal flow is broken up by the high-pressure water jet, allows gas to effectively enter the atomization core area, establishing an oxygen barrier around the micro-droplets formed at the moment the molten metal flow 16 is broken up and afterward, ensuring that newly generated high-temperature, high-specific-surface-area molten metal droplets are isolated from oxygen. Third Protection Zone 13 (Cooling and Solidification Zone): The space from the lower boundary of Second Protection Zone 12 to the bottom of Collection Cylinder 15 (i.e., z >150mm). With the central axis of the atomizing system as the guide. ZCentered on the axis, two layers of annular third gas supply devices 9 are installed on the inner wall of the atomization chamber: the top layer is located 50 mm above the lower boundary of the second protective zone 12 at a horizontal position (i.e., z = 100 mm), the second layer is located 250 mm directly below the first layer at a horizontal position (i.e., = 100 mm). z At a location of 350 mm, its vertical installation position is measured using the horizontal plane where the center of the cross-section of its annular gas distribution pipeline is located.

[0139] The third gas supply device 9 consists of an annular gas distribution pipeline, a gas supply pipeline connected to it, and several gas guide pipes located inside the distribution pipeline and extending radially towards the center. The inner diameter of the third gas supply device 9... D gas3 Let be the diameter of the geometric circle formed by the center points of the end faces of all air outlets in the guide tubes. Based on the theoretical formula for the diameter of the atomizing cone... Dz =2·| z |·tan( α / 2), calculate the top layer ( z =100mm) and the second layer ( z =350mm) The diameter of the conical surface at the vertical installation position of the third gas supply device 9 is calculated to obtain the top-level third gas supply device 9. D z3 1 =83mm, second layer third gas supply device 9 D z3 2 =290mm. According to the formula... ΔS 3= S base3 + λD z3 Set the basic safety distance for the third gas supply device 9. S base3 =130mm, diffusion safety factor of the top-level third gas supply device 9 l Using a value of 0.2, the safe avoidance distance is calculated. ΔS 3 1 = S base3 + λD z3 1 =130mm + 0.2 × 83mm = 147mm. The diffusion safety factor of the second-layer third gas supply device 9. l Taking a value of 0.2, the safe avoidance distance Δ is calculated. S 3 2 = S base3 + λD z3 2=130mm + 0.2 × 290mm = 188mm. The final inner diameter of the top-level third gas supply device 9 is determined. D gas3 1 = D z3 1 + ΔS 3 1 =83mm + 147mm = 230mm; Inner diameter of the second layer third gas supply device 9 D gas3 2 = D z3 2 + ΔS 3 2 =290mm+188mm=478mm.

[0140] Argon gas with flow rates of 20 L / min and 15 L / min is supplied to the cooling and solidification path of the atomized particles in the third protected area 13 through the third gas supply device of the top and second layers, respectively, to provide continuous atmosphere protection for the atomized particles during the long cooling and solidification process.

[0141] After the droplets are cooled and solidified under argon protection, they settle to the bottom of the collecting cylinder 15 to obtain a powder slurry.

[0142] Step S3: Dehydrate and dry the powder slurry obtained in step S2; After the obtained powder slurry is filtered to remove water, it is dried using a vacuum drying device at a temperature of 100℃ and a vacuum degree of not less than 1×10⁻⁶. -1 Pa, drying time is 1h, and the dried powder is sieved to obtain water atomized 310S stainless steel powder with different particle size ranges such as 60~100 mesh and 100~160 mesh.

[0143] The above embodiments demonstrate the specific applications of the method of the present invention in the preparation of different metal powders. The resulting powders all exhibit low oxygen content, low bulk density, and highly irregular morphology, making them suitable for functional applications such as porous materials and catalyst supports. The method of the present invention addresses the technical problems of high oxygen content and high bulk density in water-atomized powders in existing technologies through systematic melting deoxidation and zoned atmosphere protection atomization technology, while effectively controlling the content of impurity elements. The method of the present invention, through melt deoxidation and zoned atmosphere protection technology, effectively controls oxidation risk and improves powder quality.

Claims

1. A method for preparing water-atomized powder, characterized in that, Includes the following steps: Step S1: Melt and deoxidize the metal raw materials to obtain molten metal; Step S2: The molten metal obtained in step S1 is atomized under protective atmosphere to obtain a powder slurry; Step S3: Dehydrate and dry the powder slurry obtained in step S2.

2. The method for preparing water-atomized powder according to claim 1, characterized in that, Step S1 is as follows: the metal raw material is placed in an induction melting furnace (1) and heated and melted under the protection of nitrogen or argon. After the raw material is completely melted, a deoxidizer composed of ferrosilicon and calcium silicon is added in steps. After the deoxidizer is added, the metal is allowed to stand and the slag is removed to obtain the molten metal. The standing time is 5 min to 8 min.

3. The method for preparing water-atomized powder according to claim 2, characterized in that, In step S1, after adding ferrosilicon and holding it at a temperature for 1-3 minutes, calcium silicon is added. The amount of deoxidizer composed of ferrosilicon and calcium silicon added, based on Si element, is 0.6 wt.% to 1.0 wt.% of the total mass of raw materials, of which Si introduced by calcium silicon accounts for 30 wt.% to 50 wt.% of the total Si added, and the remainder Si comes from ferrosilicon. The silicon content in ferrosilicon is 70 wt.% to 75 wt.%, and the remainder is Fe and unavoidable impurities. The silicon content in calcium silicon is 60 wt.% to 65 wt.%, the calcium content is 30 wt.% to 35 wt.%, and the remainder is unavoidable impurities.

4. The method for preparing water-atomized powder according to claim 2, characterized in that, Step S2 specifically involves: Step 2.1: Preparation of atomization environment: Argon or nitrogen gas is introduced into the atomization chamber (14) to replace the air in the atomization chamber (14) and obtain a low-oxygen atomization environment with an oxygen content ≤5 vol%. Step 2.2: Atomization powder making: Adjust the position of the intermediate ladle crucible (3) so that the center of its bottom hole (4) is located on the central axis of the atomization system, ensuring that the freely falling molten metal flow (16) passes through the water atomization geometric focus (10); pour the molten metal obtained in step S1 into the intermediate ladle crucible (3) with a preheating temperature of 600℃~800℃; after the molten metal flows out through the hole (4), it enters the atomization chamber (14) and is broken into fine droplets by the high-pressure water jet from the atomization nozzle (6). During the atomization process, a zoned atmosphere protection is implemented. After the droplets are cooled and solidified under the protection of argon or nitrogen, they settle to the bottom of the collection cylinder (15) to obtain powder slurry; the pouring operation is stopped when the remaining amount of molten metal in the induction melting furnace (1) is 5%~8% of the initial mass by liquid level monitoring; In step 2.2, the vertical distance between the water atomization geometric focus (10) and the plane containing the center point of the atomizing nozzle (6) outlet is denoted as . H , H The specific relationship is determined based on the design parameters and installation angle of the atomizing nozzle, and satisfies the following formula: H =0.5 L / tan( α / 2); In the formula, for a plate-shaped V-type atomizing nozzle, L The horizontal distance between the center points of the outlets of the two oppositely arranged atomizing nozzles (6) corresponding to the water atomization geometric focus (10); for linear flow ring orifice type atomizing nozzles, L The diameter of the distribution circle at the center point of the outlet of the annular array atomizing nozzle (6) corresponding to the formation of the water atomization geometric focus (10); α For a plate-flow V-shaped atomizing nozzle, the atomization angle is [missing information]. α The angle between the geometric center planes of the opposing water jets in the thickness direction, corresponding to the geometric focus (10) of the water atomization, is required for the formation of the geometric focus (10). For linear flow ring orifice type atomizing nozzles, α The apex angle of the theoretical cone formed by the central axes of each linear water jet, corresponding to the geometric focus (10) of water atomization; In step 2.2, based on the water atomization geometric focus (10), the atomization process is spatially divided into three functional regions, and zoned atmosphere protection is implemented. The three functional regions are as follows: First protection zone (11): The continuous liquid flow channel area between the outlet of the bottom hole (4) of the intermediate crucible (3) and the water atomization geometric focus (10) is designated as the first protection zone (11). Second protection zone (12): The space area from the water atomization geometric focus (10) to 150mm~250mm below the water atomization geometric focus (10) where the metal liquid flow (16) is atomized, broken, and initially formed into micro-droplets is the second protection zone (12). Third protection zone (13): The space from the lower boundary of the second protection zone (12) to the bottom of the collection cylinder (15) is designated as the third protection zone (13).

5. The method for preparing water-atomized powder according to claim 2, characterized in that, In step S2.2, a first protection zone (11) is formed by setting the first gas supply device (7), a second protection zone (12) is formed by setting the second gas supply device (8), and a third protection zone (13) is formed by setting the third gas supply device (9). The first gas supply device (7) includes a first annular gas distribution pipe (71) and a first gas supply pipe (711). The first gas supply pipe (711) is connected to the first annular gas distribution pipe (71). A plurality of first jet holes (712) are evenly opened on the inner side of the first annular gas distribution pipe (71). The second gas supply device (8) includes a second annular gas distribution pipeline (81) and a second gas supply pipe (811). Several second gas guide pipes (812) are evenly arranged inside the second annular gas distribution pipeline (81). Several second gas guide pipes (812) and second gas supply pipes (811) are all connected to the second annular gas distribution pipeline (81). The second gas supply device (8) and the third gas supply device (9) have the same structure. The third gas supply device (9) includes a third annular gas distribution pipeline and a third gas supply pipe. Several third gas guide pipes are evenly arranged inside the third annular gas distribution pipeline. Several third gas guide pipes and third gas supply pipes are all connected to the third annular gas distribution pipeline. The first gas supply device (7) is located between the leak (4) and the upper surface of the atomizing spray plate (5); the inner diameter of the first gas supply device (7) D gas1 Based on the diameter of the leak (4) d nozzle Design, i.e. D gas1 = d nozzle + ΔS 1. In the formula, ΔS 1 is the radial safety clearance distance of the first gas supply device (7), that is, the total difference in diameter between the inner wall of the first annular gas distribution pipeline (71) and the inner wall of the leak (4); ΔS The value of 1 is 80mm~130mm; The first gas supply device (7) supplies argon or nitrogen gas with a flow rate of 10L / min to 15L / min; The second gas supply device (8) is located above the water atomization geometric focus (10). H / 2, to the inner wall of the atomizing chamber within a space of 50mm below the water atomization geometric focus (10); The second gas supply device (8) supplies argon or nitrogen gas with a flow rate of 30L / min to 40L / min; If a single-layer third gas supply device (9) is used, it is set on the inner wall of the atomizing chamber in the gas phase space above the lower boundary of the second protection zone (12) to above the cooling water surface in the collection cylinder (15); when two or three layers of third gas supply devices (9) are used for gas supply, the top layer is set at a horizontal position 50mm above the lower boundary of the second protection zone (12), and the vertical distance between each two adjacent layers is 150mm~250mm. If a single-layer third gas supply device (9) is used, argon or nitrogen is supplied at a flow rate of 15L / min to 25L / min; if a two-layer or three-layer arrangement is used, the gas flow rate of the top layer is 15L / min to 25L / min, and the gas flow rate of each layer below decreases by 5L / min in turn; to provide continuous atmosphere protection for the atomized particles in the third protection zone during the long cooling and solidification process. The minimum gas flow rate of the second gas supply device (8) in the second protected area (12) is greater than the maximum gas flow rate of the top third gas supply device (9) in the third protected area; The inner diameter of the second gas supply device (8) is D gas2 Based on the vertical installation position corresponding to the second gas supply device (8) z Theoretical atomization cone diameter at the location D z2 Design, i.e. D gas2 = D z2 + ΔS 2; where, ΔS 2 represents the radial safety clearance of the second gas supply device (8), i.e., the inner diameter of the second gas supply device (8). D gas2 The theoretical atomizing cone diameter at the corresponding vertical installation position z D z2 The total dimensional difference; where, ΔS 2 =S base2 + λD z2 In the formula, S base2 The basic safety distance for the second gas supply device (8) is ΔS The fixed constant component of 2, the radial distance on one side of the foundation reserved for the second gas supply device (8) is S base2 / 2; λ For diffusion safety factor; The inner diameter of the third gas supply device (9) is D gas3 Based on the vertical installation position corresponding to the third gas supply device (9) z Theoretical atomization cone diameter at the location D z3 Design, i.e. D gas3 = D z3 + ΔS 3; In the formula, ΔS 3 represents the radial safety clearance of the third gas supply device (9), i.e., the inner diameter of the third gas supply device (9). D gas3 Its corresponding vertical installation position z Theoretical atomization cone diameter at the location D z3 The total dimensional difference; where, ΔS 3 =S base3 + λD z3 In the formula, S base3 The basic safety distance for the third gas supply device (9) is ΔS 3 is a fixed constant component; the radial distance on one side of the foundation reserved for the third gas supply device (9) is S base3 / 2; λ This is the diffusion safety factor.

6. The method for preparing water-atomized powder according to claim 2, characterized in that, In step S2.2, when the raw material used for the molten metal obtained in step S1 is stainless steel, the atomizing water pressure at the atomizing nozzle (6) is 8MPa-10MPa, the water flow rate is 300L / min-350L / min, and the diameter of the leak (4) is 6mm-8mm. When the raw material used for the molten metal obtained in step S1 is an iron-aluminum alloy, the atomizing water pressure at the atomizing nozzle (6) is 12MPa-15MPa, the water flow rate is 250L / min-300L / min, and the diameter of the leak (4) is 8mm-10mm.

7. The method for preparing water-atomized powder according to claim 1, characterized in that, Step S3 specifically involves: after filtering out water from the powder slurry obtained in step S2, drying it using a vacuum drying device at a temperature of 80℃~120℃ and a vacuum degree of not less than 1×10⁻⁶. -1 Pa, drying time is 2h~3h, and the dried powder is sieved to obtain water atomized metal powder with different particle size ranges.

8. A water-atomized metal powder, characterized in that, It is prepared by the method described in any one of claims 1-7.

9. The application of water-atomized metal powder, characterized in that, The water-atomized metal powder prepared by the method as described in any one of claims 1-7 can be used as a sintered metal filter, a porous catalyst support, a functional coating material, or a powder raw material for additive manufacturing.

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