Metal atomization spraying disc

Abstract

The invention relates to the technical field of metal powder preparation, in particular to a metal atomization spray disc which comprises a spray disc assembly, the spray disc assembly is provided with a molten metal falling channel, a first gas runner and a second gas runner, the first gas runner is arranged around the molten metal falling channel, and the second gas runner is arranged around the molten metal falling channel; an outlet of the first gas flow channel points to an outlet area of the molten metal falling channel; the second gas flow channel is arranged around the molten metal falling channel, and an outlet of the second gas flow channel points to an outlet area of the molten metal falling channel; the gas sprayed out of the second gas flow channel prevents or inhibits backflow of the gas sprayed out of the first gas flow channel; the auxiliary gas flow ejected by the second gas flow channel directly acts on a key area between the outlet of the first gas flow channel and the outlet of the molten metal falling channel, so that high-pressure atomized gas in the main flow channel can be actively and effectively prevented or remarkably inhibited from entering the molten metal falling channel, and the problem of gas backflow is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal powder preparation, in particular to a metal atomizing spray disc, and more particularly to an atomizing spray disc assembly suitable for preparing spherical metal powder for additive manufacturing. Background Art

[0002] Additive manufacturing (commonly known as 3D printing) technology refers to a scientific and technological system that directly manufactures parts based on the discrete-accumulation principle and is driven by the three-dimensional data of the parts. It achieves rapid prototyping of parts by digitally modeling the parts, slicing them, and then manufacturing them in layers, and finally stacking them layer by layer. It is one of the rapidly developing advanced manufacturing technology directions.

[0003] Metal powder is a raw material widely used in metal additive manufacturing. It has higher requirements on the performance indicators of the powder, such as non-metallic element content, particle size distribution, sphericity, fluidity, and bulk density. For example, metal powder used in processes such as thermal spraying and powder metallurgy cannot be directly used in metal 3D printing. This puts higher demands on the preparation technology and process of special powder for metal 3D printing.

[0004] Gas atomization is widely used in industrial production due to its ability to efficiently produce metal powders with excellent sphericity and uniform composition. It is one of the main technologies for preparing metal powders that meet the requirements of additive manufacturing. Gas atomization methods are mainly divided into vacuum induction gas atomization (VIGA) and electrode induction gas atomization (EIGA). VIGA technology melts the alloy in a crucible and generally uses a confined atomizing nozzle. Confined nozzles have high atomization efficiency and are used for low-cost mass production of spherical metal powders. EIGA technology directly melts metal rods or wires using an induction coil and generally uses an unconfined atomizing nozzle. The metal droplets or liquid streams do not come into contact with the atomizing nozzle during their fall.

[0005] EIGA technology is generally used to produce highly reactive and high-melting-point metals. During the powder preparation process, this technology prevents the metal solution from coming into contact with the crucible or nozzle, preventing contamination of the powder by other impurities. The resulting spherical powder is of high quality, making it a widely used powder preparation technology. However, powders prepared using EIGA technology place high demands on the atomizing nozzle. The structure of the atomizing nozzle significantly affects the atomizing airflow field. If the atomizing airflow backflows, it will result in a large number of defective powders such as teardrop-shaped metal flakes or strip-shaped particles, affecting the powder quality and, consequently, the performance of the printed part. Summary of the Invention

[0006] The technical problem to be solved by the present invention is that part of the high-speed sprayed atomizing gas may generate eddy currents or reverse flow in the area near the outlet of the molten metal falling channel, causing part of the gas to flow into the molten metal falling channel. The purpose is to provide a metal atomizing spray disc, which optimizes the atomizing nozzle structure to improve the airflow organization in the atomizing area, inhibit or eliminate harmful gas reflux, thereby reducing the generation of defective powder and improving powder quality and yield.

[0007] The present invention is achieved through the following technical solutions: A metal atomizing spray disc, comprising: a spray disc assembly, wherein the spray disc assembly is provided with: A vertical through-hole channel for molten metal to fall; at least one first gas flow channel, which is arranged around the molten metal falling channel, and the outlet of the first gas flow channel is directed to the outlet area of ​​the molten metal falling channel; at least one second gas flow channel, which is arranged around the molten metal falling channel, and the outlet of the second gas flow channel is directed to the outlet area of ​​the molten metal falling channel; The outlet of the second gas flow channel is arranged in a region adjacent to the outlet of the first gas flow channel, so that the gas ejected from the second gas flow channel prevents or inhibits the backflow of the gas ejected from the first gas flow channel.

[0008] Specifically, the first gas flow channel includes an inclined annular slit, the lower end of which is the outlet of the first gas flow channel; the second gas flow channel includes a vertical annular slit, the lower end of which is the outlet of the second gas flow channel.

[0009] Optionally, the inclined annular seam and the vertical annular seam are both coaxially arranged with the molten metal falling channel.

[0010] Optionally, the inclined annular gap of the first gas flow channel is of Laval contraction-expansion shape.

[0011] Furthermore, the second gas flow channel further includes a flow channel front section, and the inner end of the flow channel front section is connected to the upper end of the vertical annular gap.

[0012] Optionally, the spray plate assembly includes: A flow guide pipe, wherein the molten metal falling channel is arranged inside the flow guide pipe; an upper spray plate, which is assembled on the outside of the guide tube, wherein the upper spray plate and the guide tube define the second gas flow channel in combination; The lower spray plate is assembled below the upper spray plate, and the lower spray plate and the upper spray plate are combined to define the first gas flow channel.

[0013] Optionally, at least one radial through hole is provided on the upper spray plate, and an inner end of the radial through hole is communicated with an annular gap constituting a rear section of the second gas flow channel.

[0014] Optionally, a stepped hole is provided inside the upper spray plate, the inner diameter of the lower section of the stepped hole is larger than the inner diameter of the upper section of the stepped hole, the outer surface of the guide tube is sealed with the upper section of the stepped hole, and the vertical annular gap between the outer surface of the guide tube and the lower section of the stepped hole is configured as the rear section of the second gas flow channel.

[0015] Optionally, the outer side of the lower section of the upper spray plate is set as a frustum, the assembly hole of the lower spray plate is set as a conical hole, the size of the outer side surface of the frustum is smaller than the corresponding size of the inner side surface of the conical hole, and the inclined annular gap between the outer side surface of the frustum and the inner side surface of the conical hole is configured as the first gas flow channel.

[0016] Optionally, the upper end diameter of the inclined annular gap is larger than the lower end diameter of the inclined annular gap.

[0017] Optionally, the diameter of the radial through hole is 0.3 mm to 0.8 mm, the height of the lower section of the stepped hole is not less than 5 mm, the width of the vertical annular seam is 0.2 mm to 1 mm, and the number of the radial through holes is not less than 3.

[0018] Optionally, the maximum width of the inclined annular seam is 1 mm to 3 mm, and the minimum width of the inclined annular seam is 0.2 mm to 0.8 mm.

[0019] Compared with the prior art, the present invention has the following advantages and beneficial effects: By adding a second gas flow channel, which ejects an auxiliary gas flow directly into the critical area between the outlet of the first gas flow channel and the outlet of the molten metal falling channel, the present invention can actively and effectively prevent or significantly suppress the intrusion of high-pressure atomized gas from the main flow channel into the molten metal falling channel, thus solving the problem of gas backflow. Furthermore, by avoiding interference from reflux gas, the auxiliary gas flow also helps guide the atmosphere in the molten metal channel downward, thus ensuring the stability of the molten metal flow during its fall and reducing the risk of the molten metal adhering to the inner wall of the channel. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings illustrate exemplary embodiments of the present invention and, together with the description thereof, are used to explain the principles of the present invention. These drawings are included to provide a further understanding of the present invention, and the accompanying drawings are included in and constitute a part of this specification and do not constitute a limitation of the embodiments of the present invention.

[0021] Figure 1 It is a structural schematic diagram of a metal atomizing spray disc according to the present invention.

[0022] Figure 2 2 is a schematic structural diagram of the flow guide tube according to the present invention.

[0023] Figure 3 2 is a schematic structural diagram of the upper spray plate according to the present invention.

[0024] Figure 4 2 is a schematic structural diagram of the lower spray plate according to the present invention.

[0025] Reference numerals: 1 - molten metal falling channel, 2 - first gas flow channel, 3 - second gas flow channel. DETAILED DESCRIPTION

[0026] To make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the relevant content and are not intended to limit the present invention.

[0027] It should also be noted that, for the convenience of description, only the parts related to the present invention are shown in the drawings.

[0028] In this application, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be interpreted broadly. For example, they may refer to fixed connection, detachable connection, or integration; they may refer to direct connection or indirect connection through an intermediate medium; they may refer to internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0029] In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0030] In the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0031] Gas atomization is widely used in industrial production due to its ability to efficiently produce metal powders with good sphericity and uniform composition. It is one of the main technologies for preparing metal powders that meet the requirements of additive manufacturing. Common gas atomization technologies include vacuum induction melting gas atomization (VIGA) and electrode induction melting gas atomization (EIGA). EIGA technology directly melts consumable electrode rods through an induction coil. During its fall, the molten metal does not come into contact with the crucible or (typically) confined nozzle. This non-contact or near-non-contact melting and atomization method can effectively avoid contamination of ceramic materials. Therefore, it is particularly suitable for preparing high-purity, high-melting-point, or chemically active metal and alloy powders. It is usually used in conjunction with an unrestricted or free-fall atomization nozzle structure.

[0032] In some existing gas atomization processes, particularly when using certain atomizing nozzle configurations, the flow field stability of the high-pressure atomizing gas flow in the nozzle core region remains a persistent concern. Specifically, some of the high-speed atomizing gas may generate eddies or reverse flow near the exit of the molten metal drop channel, a phenomenon known as gas backflow, causing some gas to enter the drop channel. This undesirable gas backflow disrupts the stable descent of the molten metal stream and its interaction and fragmentation with the main atomizing gas flow. Unstable gas flow can entrain molten metal droplets or affect the molten column morphology, leading to the formation of droplet-shaped (tailing) particles, elongated particles, satellites, and other irregularly shaped defective powders. The presence of these defective powders not only significantly reduces the overall quality of the finished powder (such as flowability and bulk density), potentially affecting the stability of the additive manufacturing process and the density and mechanical properties of the final part, but also directly reduces the effective yield of spherical powders that meet high-quality requirements.

[0033] Therefore, how to optimize the atomizing nozzle structure to improve the airflow organization in the atomizing area, inhibit or eliminate harmful gas backflow, thereby reducing the generation of defective powders, improving powder quality and yield, is a technical direction that continues to seek improvement in the field of gas atomization powder making technology. In order to solve the above technical problems, the present invention proposes an atomizing spray disc assembly suitable for preparing high-performance spherical metal powders for additive manufacturing. Figure 1 、 Figure 2 、 Figure 3 and Figure 4 The present invention will be described in detail with reference to the embodiments.

[0034] Example 1 like Figure 1 As shown, a metal atomizing spray plate is provided, including: a spray plate assembly, the spray plate assembly is provided with: a metal melt falling channel 1, a first gas flow channel 2 and a second gas flow channel 3.

[0035] The vertical through-going molten metal falling channel 1 is for the molten metal to flow downward under the action of gravity, and the gas flow channel is an internal channel or path for guiding the flow of a specific gas.

[0036] At least one first gas flow channel 2 is disposed around the molten metal falling channel 1, with its outlet directed toward the outlet region of the molten metal falling channel 1. The purpose of the first gas flow channel 2 is to deliver high-pressure gas (typically an inert gas, such as argon or nitrogen, serving as the primary atomizing gas) that is ejected at high speed at its outlet, directly impacting and fragmenting the molten metal stream exiting the molten metal channel, atomizing it into fine molten droplets. To achieve effective atomization, the outlet of the first gas flow channel 2 is designed to face or point toward the outlet region of the molten metal channel.

[0037] At least one second gas flow channel 3 is arranged around the molten metal falling channel 1, and the outlet of the second gas flow channel 3 points to the outlet area of ​​the molten metal falling channel 1; similar to the first gas flow channel 2, the outlet of the second gas flow channel 3 is also designed to point to the outlet area of ​​the molten metal channel.

[0038] The outlet of the second gas flow channel 3 is arranged in a region adjacent to the outlet of the first gas flow channel 2 , so that the gas ejected from the second gas flow channel 3 prevents or inhibits the gas ejected from the first gas flow channel 2 from flowing back.

[0039] The key points of this embodiment lie in the relative layout and functional coordination of the first and second gas flow channels 2 and 3. The outlet of the second gas flow channel 3 is located adjacent to the outlet of the first gas flow channel 2. That is, the two outlets are spatially close to each other, allowing the gas (auxiliary gas flow) ejected from the second gas flow channel 3 to effectively act on the area near the outlet of the first gas flow channel 2, preventing or inhibiting the backflow of the main atomizing gas flow ejected from the first gas flow channel 2. Backflow refers to the phenomenon in which part of the main atomizing gas flow does not flow in the intended direction (usually downward or outward), but instead flows in the opposite direction or swirls, or even penetrates into the upstream molten metal falling channel 1.

[0040] It should be emphasized that when describing the "spray plate assembly" in Example 1, the focus is on the relative positions and functional relationships of the three core flow channels (molten metal falling channel 1, first gas flow channel 2, second gas flow channel 3) and their outlets that must be included in the assembly (i.e., the second flow channel inhibits the backflow of the first flow channel), but it does not limit the "spray plate assembly" itself to a combination of specific, separate components.

[0041] This means that the physical structure of the spray disc assembly that can achieve the functional layout required by this embodiment can have considerable flexibility. For example, the spray disc assembly can be manufactured entirely in an "integrated molding" manner. With the help of advanced manufacturing processes, such as metal additive manufacturing (metal 3D printing) technologies such as selective laser melting (SLM), or high-precision investment casting combined with complex internal flow channel electrospark machining and other technologies, in theory, the entire spray disc assembly containing the complex internal molten channel, the first gas flow channel 2 and the second gas flow channel 3 can be directly manufactured as a single, seamless integral component. This integrated structure may bring higher structural strength, better sealing or more precise flow channel control.

[0042] In addition to the multi-component combination structure that may be described in subsequent embodiments (such as the combination of the guide tube, the upper spray plate, and the lower spray plate in the third embodiment) and the above-mentioned one-piece molding structure, we can also envision many other possible structural forms to achieve the core functional requirements defined in the first embodiment, such as: Concentric Tube Structure: The core of the spray plate can be constructed from several layers of precisely machined, nested concentric circular or shaped tubes. The innermost tube forms the molten metal drop channel 1. The annular gap between the inner and middle tubes can be designed as a secondary gas flow channel 3 (auxiliary flow channel), while the annular gap between the middle tube and the outermost tube (or the inner wall of the spray plate) serves as the primary gas flow channel 2 (main flow channel). This structure creates a flow channel layout surrounding the central channel.

[0043] Porous Media Permeation Structure: In a specific area surrounding the melt channel outlet and adjacent to the outlet of the first gas flow channel 2, the spray plate assembly is partially constructed of a porous material (such as porous ceramics or sintered metal fiber felt) with a specific porosity and permeability. The secondary gas (auxiliary gas) is introduced into this porous medium area, where it evenly permeates the surface of the porous material, forming a diffuse "air film" or "air curtain" covering the specific area. This diffuse airflow functions as the second gas flow channel 3, preventing or suppressing backflow from the first gas flow channel 2.

[0044] Microchannel / micronozzle array structure: The function of the second gas flow channel 3 (auxiliary flow channel) is achieved by using precision machining techniques (such as laser micromachining and MEMS processes) to create at least three microchannels or micronozzle arrays pointing in specific directions near the outlet of the first gas flow channel 2. The microchannels are uniformly supplied with gas from one or more plenums within the spray plate. By precisely designing the outlet position, angle, and aperture of each microchannel, one or more auxiliary jets can be formed to work together to interfere with and suppress backflow from the main flow channel.

[0045] Split-Unit Precision Assembly: Unlike the top-and-bottom stacking and sealing concept of Example 3, the entire spray plate assembly can be split axially or radially into two or more main structural blocks. Complex internal flow channels (including the molten metal drop channel 1, and part or all of the first and second gas flow channels 2 and 3) can be pre-formed with grooves on the mating surfaces of these structural blocks through precision machining (such as milling or electro-discharge). When these structural blocks are precisely aligned and secured together, these grooves form a closed, fully functional internal flow channel system.

[0046] Example 2 This embodiment further clarifies the specific geometrical shape and internal structure of the first gas flow channel 2 and the second gas flow channel 3 on the basis of the dual-flow channel spray plate assembly described in the first embodiment.

[0047] The first gas flow channel 2, which is mainly used for atomization, includes an inclined annular gap, and the lower end of the inclined annular gap is the outlet of the first gas flow channel 2; the annular gap refers to an annular gap formed around the molten metal falling channel 1, and the inclination means that the wall of the annular gap has a certain angle relative to the central axis of the spray disc, rather than being completely horizontal, so that the gas ejected from the first gas flow channel 2 can impact the downstream molten metal. The lower end of the inclined annular gap (that is, the lower side of the flow channel end) is defined as the outlet of the first gas flow channel 2.

[0048] The second gas flow channel 3, which is mainly used to suppress backflow, includes a vertical annular seam, the lower end of which is the outlet of the second gas flow channel 3. The vertical annular seam also surrounds the molten metal falling channel 1, but its direction is basically vertical (parallel to the central axis), and its lower end constitutes the outlet of the second gas flow channel 3.

[0049] The inclined annular seam and the vertical annular seam are both coaxially arranged with the metal melt falling channel 1 .

[0050] The inclined annular gap of the first gas flow channel 2 features a Laval converging-diverging configuration. This is a unique nozzle internal profile design, often referred to as a Laval nozzle. Its characteristic is that the channel's cross-sectional area gradually decreases (the converging section), reaches a narrowest point (the throat), and then gradually expands (the diverging section). This configuration enables high-pressure gas to effectively expand and accelerate to high velocities within the nozzle, thereby providing powerful kinetic energy for atomization.

[0051] Finally, because the rear section of the second gas flow channel 3 is actually a vertical structure, in order to enable the auxiliary gas to be connected to the vertical annular gap, the second gas flow channel 3 also includes a front section of the flow channel, and the inner end of the front section of the flow channel is connected to the upper end of the vertical annular gap, that is, the second gas flow channel 3 is composed of the front section of the flow channel and the vertical annular gap in series.

[0052] The coaxial configuration ensures that the main atomizing gas flow is evenly distributed around the melt stream, facilitating uniform crushing and highly spherical powder particles. The angled design may help direct the initial momentum of the gas flow toward the melt stream, enhancing interaction or confining the atomization zone. The Laval design accelerates the gas, impacting the melt stream with powerful kinetic energy, achieving efficient primary atomization, potentially resulting in a finer average particle size and narrower particle size distribution.

[0053] Example 3 like Figure 2 、 Figure 3 and Figure 4 As shown, this embodiment provides a specific structure of a spray plate assembly, which includes: a guide pipe, an upper spray pipe and a lower spray pipe.

[0054] The molten metal falling channel 1 is arranged inside the guide pipe; The upper spray plate is assembled on the outside of the guide tube, and the upper spray plate and the guide tube define a second gas flow channel 3; The lower spray plate is assembled below the upper spray plate, and the lower spray plate and the upper spray plate are combined to define a first gas flow channel 2.

[0055] At least one radial through hole is provided on the upper spray plate, and the inner end of the radial through hole is communicated with the annular gap constituting the rear section of the second gas flow channel 3 .

[0056] A stepped hole is provided inside the upper spray plate, the inner diameter of the lower section of the stepped hole is larger than the inner diameter of the upper section of the stepped hole, the outer side surface of the guide tube is sealed with the upper section of the stepped hole, and the vertical annular gap between the outer side surface of the guide tube and the lower section of the stepped hole is configured as the rear section of the second gas flow channel 3.

[0057] This embodiment discloses in detail how the second gas flow channel 3 (including the front and rear sections) is realized through the structure of the upper spray plate and the guide pipe.

[0058] Formation of the rear section (vertical annular gap): A stepped hole is defined within the upper spray plate. This hole's inner diameter is not constant but varies in sections, with the lower section's inner diameter being larger than the upper section's. When the flow tube is inserted into this stepped hole, the tube's outer surface seals against the narrower inner wall of the stepped hole's upper section, ensuring a tight fit or seal. A predetermined gap exists between the tube's outer surface and the wider inner wall of the stepped hole's lower section, forming the vertical annular gap surrounding the tube. This gap is designated as the rear section of the second gas flow channel 3.

[0059] Front Section (Radial Through Hole) and Its Connection: Radial through holes are provided in the upper spray disc, extending radially (approximately toward or away from the central axis) from the outer periphery or other appropriate locations into the interior of the disc. The inner end of the radial through hole (the end closest to the central axis) is connected to the upper portion of the vertical annular gap formed by the stepped hole (i.e., the rear section of the second gas flow channel 3). Externally introduced gas can pass through the radial through hole and converge into the vertical annular gap, thus forming the complete second gas flow channel 3 (radial through hole in the front section and vertical annular gap in the rear section).

[0060] The outer side of the lower section of the upper spray disc is set as a frustum, and the assembly hole of the lower spray disc is set as a conical hole. The size of the outer side of the frustum is smaller than the corresponding size of the inner side of the conical hole. The inclined annular gap between the outer side of the frustum and the inner side of the conical hole is configured as the first gas flow channel 2.

[0061] The upper end diameter of the inclined annular gap is larger than the lower end diameter of the inclined annular gap.

[0062] This embodiment describes in detail how the first gas flow channel 2 (inclined annular gap) is formed by the cooperation of the upper and lower spray discs: Matching interface shape: The outer surface of the lower section of the upper spray plate is processed into a frustum shape. The assembly hole on the lower spray plate used to match the upper spray plate is also processed into a cone hole.

[0063] Formation of the gap (inclined annular gap): During assembly, the outer surface of the upper cone of the spray plate and the inner surface of the cone of the lower spray plate do not completely fit together, but rather maintain a specific gap. The outer surface of the cone is smaller than the corresponding inner surface of the cone, creating an annular gap between the two conical surfaces—the inclined annular gap—which serves as the first gas flow channel 2.

[0064] The three-component assembly structure described in this embodiment, consisting of a "flow guide tube," an upper spray plate, and a lower spray plate, translates the functional principles and geometric features described in Examples 1 and 2 into a concrete, easily fabricated, and implementable engineering solution. This design choice inherently incorporates considerations of manufacturing process, assembly precision, material application, and maintainability. Furthermore, the combination of multiple discrete components generally reduces the machining complexity of individual parts.

[0065] The multi-component design allows for the selection of the most appropriate materials based on the operating environment and functional requirements of each component. The flow guide tube, which comes into direct contact with high-temperature molten metal, typically requires materials that are heat-resistant, chemically stable, and resistant to molten metal corrosion, such as specialty ceramics (zirconia, silicon nitride, etc.) or refractory metals (molybdenum, tungsten, etc.). The upper and lower spray plates primarily withstand the high temperature and high-pressure airflow, requiring excellent high-temperature strength, oxidation resistance, and a certain degree of machinability. High-temperature alloys (such as nickel- or cobalt-based superalloys) or stainless steel may be used.

[0066] During use, certain components (particularly the flow guide tube, which comes into direct contact with the melt, or the nozzle outlet area, which is subject to high-speed airflow) may wear or damage. The multi-component structure makes it possible to inspect, clean, or replace specific components, reducing maintenance costs and extending the service life of the entire device.

[0067] Example 4 This embodiment provides preferred size ranges and quantity parameters of key geometric features constituting the first gas flow channel 2 and the second gas flow channel 3 .

[0068] The diameter of the radial through hole is 0.3mm to 0.8mm, the height of the lower section of the stepped hole is not less than 5mm, the width of the vertical annular gap is 0.2mm to 1mm, and the number of radial through holes is not less than 3. The maximum width of the inclined annular gap is 1mm to 3mm, and the minimum width of the inclined annular gap is 0.2mm to 0.8mm.

[0069] Provide a specific example.

[0070] Parameters of the first gas channel 2: Maximum width of inclined annular seam: 2mm; Minimum width of inclined annular seam (throat): 0.4mm; Second gas flow channel 3 parameters: Radial through hole diameter: 0.8mm; Vertical annular seam width: 1mm; Vertical annular seam height (i.e. the height of the lower section of the stepped hole): 11mm; Number of radial through holes: should be no less than 3, generally no more than 9, and should be distributed symmetrically along the axial direction.

[0071] The total height of the spray plate in this example is 40 mm.

[0072] The traditional gas atomizing spray plate has only one atomizing gas flow channel, and high-pressure atomizing gas is ejected from this flow channel to atomize the metal solution. The atomizing gas tends to flow back under the guide tube, and the metal solution is drawn back into the guide tube. The metal solution hits the inner wall of the guide tube, thereby forming defective powders such as teardrop-shaped metal sheets or strip-shaped metal particles. The present invention has two atomizing gas flow channels. The first gas flow channel 2 is an inclined annular seam. This flow channel is the main flow channel of the atomizing gas. The high-pressure gas ejected from this flow channel atomizes the metal solution; the second gas flow channel 3 is a connecting area formed by the horizontal through hole and the vertical annular seam of the upper spray plate. This flow channel is an auxiliary flow channel. Its main function is to prevent the gas ejected from the first gas flow channel 2 from flowing back into the guide tube, and to guide the gas in the guide tube to flow downward. Therefore, the effects of the present invention are as follows: (1) The horizontal through hole of the upper spray plate and the vertical annular gap formed by the combination of the upper spray plate and the guide tube form an auxiliary flow channel for the atomizing gas.

[0073] (2) The atomized gas ejected from the auxiliary flow channel can prevent the atomized gas ejected from the main flow channel from flowing back into the guide tube.

[0074] (3) Effectively reduce the number of defective powders such as teardrop-shaped metal flakes and strip-shaped metal particles.

[0075] (4) The atomized gas ejected from the auxiliary flow channel can guide the gas in the guide tube to flow downward, preventing the metal solution from sticking to the wall.

[0076] In the description of this specification, the description with reference to the terms "one embodiment / method", "some embodiments / methods", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / method or example are included in at least one embodiment / method or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment / method or example. Moreover, the specific features, structures, materials or characteristics described may be combined in an appropriate manner in any one or more embodiments / methods or examples. In addition, those skilled in the art may combine and combine different embodiments / methods or examples described in this specification and the features of different embodiments / methods or examples, unless they are contradictory.

[0077] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0078] It should be understood by those skilled in the art that the above embodiments are merely for the purpose of illustrating the present invention clearly, and are not intended to limit the scope of the present invention. For those skilled in the art, other changes or modifications may be made based on the above invention, and these changes or modifications are still within the scope of the present invention.

Claims

1. A metal atomizing spray disc, characterized in that: include: A spray disc assembly, the spray disc assembly being provided with: A vertical through-hole molten metal falling channel (1); at least one first gas flow channel (2) arranged around the molten metal falling channel (1), the outlet of the first gas flow channel (2) pointing to the outlet area of ​​the molten metal falling channel (1); at least one second gas flow channel (3) arranged around the molten metal falling channel (1), the outlet of the second gas flow channel (3) pointing to the outlet area of ​​the molten metal falling channel (1); The outlet of the second gas flow channel (3) is arranged in an adjacent area to the outlet of the first gas flow channel (2), so that the gas ejected from the second gas flow channel (3) prevents or inhibits the gas ejected from the first gas flow channel (2) from flowing back.

2. A metal atomizing spray disc according to claim 1, characterized in that: The first gas flow channel (2) comprises an inclined annular slit, the lower end of which is the outlet of the first gas flow channel (2); the second gas flow channel (3) comprises a vertical annular slit, the lower end of which is the outlet of the second gas flow channel (3).

3. A metal atomizing spray disc according to claim 2, characterized in that: The inclined annular seam and the vertical annular seam are both coaxially arranged with the molten metal falling channel (1).

4. A metal atomizing spray disc according to claim 2, characterized in that: The inclined annular gap of the first gas flow channel (2) is of a Laval contraction-expansion shape.

5. A metal atomizing spray disc according to claim 2, characterized in that: The second gas flow channel (3) further comprises a flow channel front section, the inner end of the flow channel front section being in communication with the upper end of the vertical annular gap.

6. A metal atomizing spray disc according to claim 2, characterized in that: The spray plate assembly includes: A guide pipe, wherein the molten metal falling channel (1) is arranged inside the guide pipe; An upper spray plate, which is mounted on the outside of the guide tube, wherein the upper spray plate and the guide tube define the rear section of the second gas flow channel (3); A lower spray plate is mounted below the upper spray plate, and the lower spray plate and the upper spray plate are combined to define the first gas flow channel (2).

7. A metal atomizing spray disc according to claim 6, characterized in that: At least one radial through hole is provided on the upper spray plate, and the inner end of the radial through hole is communicated with the annular gap constituting the rear section of the second gas flow channel (3).

8. A metal atomizing spray disc according to claim 6, characterized in that: A stepped hole is provided inside the upper spray plate, the inner diameter of the lower section of the stepped hole is larger than the inner diameter of the upper section of the stepped hole, the outer side surface of the guide tube is sealed with the upper section of the stepped hole, and the vertical annular gap between the outer side surface of the guide tube and the lower section of the stepped hole is configured as the rear section of the second gas flow channel (3).

9. A metal atomizing spray disc according to claim 6, characterized in that: The outer side of the lower section of the upper spray disc is configured as a frustum, the assembly hole of the lower spray disc is configured as a conical hole, the size of the outer side surface of the frustum is smaller than the corresponding size of the inner side surface of the conical hole, and the inclined annular gap between the outer side surface of the frustum and the inner side surface of the conical hole is configured as the first gas flow channel (2).

10. The metal atomizing spray disc according to claim 6, characterized in that: The upper end diameter of the inclined annular gap is larger than the lower end diameter of the inclined annular gap.

11. The metal atomizing spray disc according to claim 8, characterized in that: The diameter of the radial through hole is 0.3mm~0.8mm, the height of the lower section of the stepped hole is not less than 5mm, the width of the vertical annular gap is 0.2mm~1mm, and the number of the radial through holes is not less than 3.

12. The metal atomizing spray disc according to claim 9, characterized in that: The maximum width of the inclined annular seam is 1 mm to 3 mm, and the minimum width of the inclined annular seam is 0.2 mm to 0.8 mm.

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