Metal powder preparation device and preparation method

Abstract

The invention provides a metal powder preparation device and method. The device comprises a metal melting part, and the metal melting part is used for melting a metal material to obtain molten metal; the atomization part communicates with the metal melting part and comprises an atomizer, a gas supply part and an atomization chamber, the gas supply part communicates with the atomizer, the atomizer conducts atomization treatment on molten metal, the gas supply part introduces preheated inert gas and thermal cracking precursor mixed gas into the atomizer, and atomized metal enters the atomization chamber to be cooled; and the collecting part is used for collecting the cooled metal powder. Preheated inert gas and a thermal cracking precursor are introduced into the atomizer through the gas supply part, the atomization effect is improved, the sphericity degree of powder is improved, meanwhile, the influence on the metal temperature at the moment of droplet atomization is small, the thermal cracking reaction occurs when the thermal cracking precursor makes contact with the metal droplets with the high temperature, and the thermal cracking effect is improved. Therefore, metal powder with a coating structure or doped substances is formed, and satellite powder formed by adhesion of the powder is prevented.

Description

Technical Field

[0001] This specification relates to the field of metal powder preparation technology, specifically to a metal powder preparation apparatus and preparation method. Background Technology

[0002] Spherical metal powders have a wide range of applications in cutting-edge manufacturing fields such as 3D printing and injection molding. Currently, gas atomization is the mainstream method for low-cost, large-scale preparation of metal powders for 3D printing. However, this method has many limitations, such as: metals with high laser reflectivity, such as gold, silver, and copper, are not conducive to 3D printing. At present, methods to improve laser absorption rate are mostly to post-process and mix materials with high laser absorption rate through ball milling, homogenization, etc., to obtain composite powders with higher laser absorption rate. However, in the post-processing process, oxidation and impurities are easily introduced. Gas atomization powder preparation results in a low particle size recovery rate of metal powders suitable for 3D printing. In the process of gas atomization powder preparation, metal powders of different particle sizes are obtained with different cooling times, which can easily lead to agglomeration and the formation of satellite powders. Summary of the Invention

[0003] In view of this, the embodiments of this specification provide a metal powder preparation apparatus and preparation method. A preheated inert gas and a thermal decomposition precursor are introduced into the atomizer through the gas supply section. The preheated gas is beneficial to improve the atomization effect, improve the sphericity and powder collection rate of the powder, and has little impact on the metal temperature at the moment of droplet atomization. The thermal decomposition precursor undergoes a thermal decomposition reaction when it comes into contact with the high-temperature metal droplets, thereby forming a functional metal powder with a coating structure or containing doped substances, and preventing the powder from sticking together to form satellite powder.

[0004] This specification provides the following technical solution through its embodiments: a metal powder preparation apparatus, the apparatus comprising: A metal melting section, used for melting metal materials to obtain molten metal; The atomizing section is connected to the metal melting section. The atomizing section includes an atomizer, a gas supply section, and an atomizing chamber. The gas supply section is connected to the atomizer. The atomizer atomizes the molten metal that enters it. The gas supply section introduces inert gas and preheated thermal decomposition precursor into the atomizer so that the molten metal forms coated or doped metal powder during atomization. The atomized metal enters the atomizing chamber for cooling. The collection section is connected to the atomization chamber and collects the cooled metal powder.

[0005] Preferably, the gas supply unit includes a first gas storage tank, a second gas storage tank, and a preheating device. Both the first and second gas storage tanks are connected to the preheating device. The inert gas output from the first gas storage tank flows into the atomizer after passing through the preheating device, and the pyrolysis precursor output from the second gas storage tank flows into the atomizer after being heated by the preheating device.

[0006] Preferably, the preheating device uses one of induction heating, radiation heating, resistance heating or plasma heating for heating.

[0007] Preferably, the atomizing unit further includes an induced draft fan and a cyclone separator. The induced draft fan is connected to the cyclone separator, and the cyclone separator is connected to the atomizing chamber. This allows for rapid cooling of the atomized metal droplets within the atomizing chamber to form coated or doped metal powder, and enables preliminary particle size classification of the product.

[0008] Preferably, the collection section includes a first collection tank and a second collection tank, the first collection tank being installed at the bottom of the cyclone separator and the second collection tank being installed at the bottom of the atomization chamber.

[0009] A method for preparing metal powder, applied to the apparatus described in any of the above claims, for preparing metal powder with high laser absorptivity and / or high flowability, comprising the following steps: The device is evacuated, and inert gas is introduced into the atomizer through the gas supply section to atmospheric pressure. The metal melting section melts the metal material to obtain metal droplets. The atomizer is filled with a mixture of inert gas and thermal decomposition precursor, which is preheated to the first temperature. After the mixed gas enters the atomizer, it atomizes the metal droplets. The thermal decomposition precursor is further heated on the surface of the metal droplets and undergoes a thermal decomposition reaction. The decomposition products are coated or doped on the surface of the metal droplets. The coated or doped metal droplets enter the atomization chamber for cooling, and then the cooled metal powder is collected by the collection section.

[0010] Preferably, the pyrolysis precursor includes at least one of silicon hydrogen gas, hydrocarbon gas, boron hydrogen gas, ammonia, ammonia borane and its derivatives, boron trichloride, borazine, boron oxide, and sodium borohydride.

[0011] Preferably, the first temperature is lower than the thermal decomposition temperature of the thermal decomposition precursor, and the range of the first temperature is between 100-800°C. Preferably, the metallic material includes at least one selected from titanium and titanium alloys, copper and copper alloys, aluminum and aluminum alloys, iron and iron alloys, and nickel and nickel alloys.

[0012] Preferably, the inert gas includes a single gas such as argon, nitrogen, hydrogen, or helium, or a mixture thereof.

[0013] Compared with the prior art, the beneficial effects that at least one technical solution adopted in the embodiments of this specification can achieve include at least: Preheated inert gas and thermal decomposition precursor are introduced into the atomizer through the gas supply section. The preheated gas helps to improve the atomization effect and the sphericity of the powder. At the same time, it has little impact on the metal temperature at the moment of droplet atomization. The thermal decomposition precursor undergoes a thermal decomposition reaction when it comes into contact with the high-temperature metal droplets, thereby forming metal powder with a coating structure or containing doped substances. This prevents the powder from sticking together and forming satellite powder, thus obtaining composite metal powder with coating or containing doped substances. This can not only reduce the laser reflectivity of some powders, but also be used to prepare reinforcing phase doped metal powders. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the metal powder preparation apparatus provided in this application.

[0016] In the figure, 1 is the metal melting section; 2 is the atomizer; 3 is the atomization chamber; 4 is the first gas storage tank; 5 is the second gas storage tank; 6 is the preheating device; 7 is the induced draft fan; 8 is the cyclone separator; 9 is the first receiving tank; and 10 is the second receiving tank. Detailed Implementation

[0017] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0018] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0020] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. The drawings only show the components related to this application and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0021] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.

[0022] Spherical metal powders have extremely wide applications in cutting-edge manufacturing fields such as 3D printing and injection molding. Among these cutting-edge technologies, 3D printing stands out with a series of remarkable advantages: it can create complex and intricate structures, achieving rapid transformation of designs into physical objects; it can perfectly balance high strength and lightweight products; and it boasts extremely high material utilization. With these characteristics, 3D printing technology has risen to become one of the most rapidly developing core technologies in the current advanced manufacturing industry.

[0023] At present, gas atomization is the mainstream method for low-cost, large-scale preparation of metal powders for 3D printing. However, this method has many limitations, such as the wide particle size distribution of the prepared metal powder, low particle size recovery rate of the metal powder suitable for 3D printing, and the fact that metal powders of different particle sizes have different cooling times during the powder preparation process, which can easily cause them to stick together and produce satellite powder.

[0024] Furthermore, the low laser absorption rate of metals such as copper, silver, and gold can negatively impact the quality of printed products. Currently, post-processing methods are often used to improve the laser absorption rate of metal powders. For example, patent CN118023539A discloses a method to improve the laser absorption rate of copper by adding graphene and yttrium oxide combined with ultrasonic dispersion and vacuum homogenization to obtain a composite powder. Patent CN118832156A discloses a method to prepare Cu@Mo powder for additive manufacturing with high laser absorption rate by ball milling a mixture of molybdenum powder and copper powder. Metals with high laser reflectivity, such as gold, silver, and copper, are post-processed with materials with high laser absorption rates through ball milling, homogenization, etc., to obtain composite powders with higher laser absorption rates. However, during the post-processing process, oxidation and impurities are easily introduced.

[0025] For example, patent CN105965025B discloses a method and apparatus for producing high-strength, high-conductivity graphene copper-based powder materials. A carbon-source gas is introduced into an atomization chamber, and a heating plate is arranged in the atomization chamber. The purpose is to prevent the copper-based powder from cooling and the carbon source gas from undergoing a cracking reaction. This method easily causes the metal powder to stick together in the atomization chamber, affecting spheroidization and the powder collection efficiency of the product. Moreover, the heated carbon source gas undergoes a cracking reaction after reaching the cracking temperature in the atomization chamber, inevitably producing free solid carbon products that are not on the surface of the metal powder, affecting the purity of the product.

[0026] The inventors conducted extensive and in-depth experiments and designed a metal powder preparation device and preparation method.

[0027] The technical solutions provided by the various embodiments of this application are described below with reference to the accompanying drawings.

[0028] like Figure 1 As shown, a metal powder preparation apparatus includes: Metal melting section 1, which is used to melt metal materials to obtain molten metal; The atomizing section is connected to the metal melting section 1. The atomizing section includes an atomizer 2, a gas supply section, and an atomizing chamber 3. The gas supply section is connected to the atomizer 2. The atomizer 2 atomizes the molten metal that enters it. The gas supply section introduces inert gas and preheated thermal decomposition precursor into the atomizer 2 so that the molten metal forms coated or doped metal powder during atomization. The atomized metal enters the atomizing chamber 3 for cooling. The collection section is connected to the atomization chamber 3 and collects the cooled metal powder.

[0029] First, a vacuum is drawn into the device. Then, inert gas is introduced through the gas supply section to prevent oxidation of the metal material. The metal material is melted in the metal melting section 1 to obtain a metal solution. The metal solution flows into the atomizer 2, where it disperses the molten metal into fine droplets. The gas supply section introduces preheated inert gas and a thermal decomposition precursor into the atomizer 2. The inert gas serves as the main atomization medium to prevent metal oxidation. The preheated gas helps improve the atomization effect and the sphericity of the powder. At the same time, it has little impact on the metal temperature at the moment of droplet atomization. The thermal decomposition precursor undergoes a thermal decomposition reaction when it comes into contact with the high-temperature metal droplets, thereby forming metal powder with a coating structure or containing doped substances. This prevents the powder from sticking together and forming satellite powder, resulting in a coated or doped composite metal powder. The coated or doped composite metal powder enters the atomization chamber 3 and is cooled inside. The cooled metal powder is then collected by the collection section.

[0030] It should be noted that the pyrolysis precursor is below the pyrolysis temperature in atomization chamber 3, and therefore will not undergo a pyrolysis reaction, thus avoiding contamination of the powder product. Obtaining composite metal powders in a coated state or containing doped substances can not only reduce the laser reflectivity of some powders, but also be used to prepare reinforcing phase doped metal powders.

[0031] like Figure 1 As shown, in some embodiments, the gas supply unit includes a first gas storage tank 4, a second gas storage tank 5, and a preheating device 6. Both the first gas storage tank 4 and the second gas storage tank 5 are connected to the preheating device 6. The inert gas output from the first gas storage tank 4 flows into the atomizer 2 after passing through the preheating device 6, and the pyrolysis precursor output from the second gas storage tank 5 flows into the atomizer 2 after being heated by the preheating device 6. The first gas storage tank 4 stores inert gas and is connected to the preheating device 6 to ensure that the inert gas reaches the set temperature before entering the atomizer 2. The second gas storage tank 5 stores the pyrolysis precursor and is also connected to the preheating device 6 to ensure that the pyrolysis precursor reaches the set temperature before entering the atomizer 2. The preheated pyrolysis precursor has improved pyrolysis efficiency, allowing it to react rapidly with the surface of the molten metal droplets to generate a uniform coating layer or dopant, significantly improving the powder laser absorption rate. The preheated gas effectively improves the atomization effect and gas flow rate, increases the sphericity of the powder, reduces the satellite powder ratio, and enhances the bonding strength between the coating or dopant and the matrix interface.

[0032] like Figure 1As shown, in some embodiments, the preheating device 6 uses one of induction heating, radiation heating, resistance heating, or plasma heating for heating. In this embodiment, plasma heating is used, utilizing an electric arc or high-frequency electric field to ionize the gas and form high-temperature plasma, resulting in extremely high heating efficiency. High-energy particles in the plasma promote the dissociation of gas molecules, enhancing the bonding strength between the coating layer or dopant and the metal substrate. In other embodiments, induction heating, radiation heating, resistance heating, etc., can also be used, and the appropriate method can be selected based on the actual situation.

[0033] like Figure 1 As shown, in some embodiments, the atomizing unit further includes a blower 7 and a cyclone separator 8. The blower 7 is connected to the cyclone separator 8, which is connected to the atomizing chamber 3. This allows for rapid cooling of the atomized metal droplets within the atomizing chamber 3, forming coated or doped metal powder. The blower 7 accelerates the gas flow within the atomizing chamber 3 through negative pressure suction, controlling the trajectory and residence time of the atomized metal droplets. Simultaneously, it rapidly introduces the mixture of high-temperature gas and uncondensed droplets into the cyclone separator 8. The cyclone separator 8 utilizes centrifugal force to achieve gas-solid separation, efficiently separating and collecting the solidified metal powder from the airflow.

[0034] like Figure 1 As shown, in some embodiments, the collection unit includes a first collection tank 9 and a second collection tank 10. The first collection tank 9 is installed at the bottom of the cyclone separator 8, and the second collection tank 10 is installed at the bottom of the atomization chamber 3. The first collection tank 9, installed at the bottom of the cyclone separator 8, is used to capture the target particle size powder separated by the cyclone separator 8, achieving efficient collection through gravity settling and gas-solid separation. The second collection tank 10, installed at the bottom of the atomization chamber 3, mainly collects coarse powder that settles naturally due to gravity during atomization, preventing fine powder from escaping or coarse powder from accumulating and affecting atomization stability.

[0035] Based on the same inventive concept, this specification provides a method for preparing metal powder. Please refer to [link / reference]. Figure 1 The apparatus described in any of the above description is used to prepare metal powders with high laser absorptivity and / or high flowability, comprising the following steps: The device is evacuated, and inert gas is introduced into the atomizer 2 through the gas supply section to atmospheric pressure. The metal melting section 1 melts the metal material to obtain metal droplets. The metal melting section 1 heats the metal material to above the melting point to form a continuous flow of molten metal, which forms droplets through the nozzle of the atomizer 2. Vacuuming removes oxygen and moisture to prevent oxidation during metal melting and atomization. Inert gas replacement ensures a low oxygen content in the atomization environment, avoiding the formation of an oxide layer on the surface of the metal droplets. The atomizer 2 is filled with a mixture of inert gas and thermal decomposition precursor, which is preheated to the first temperature. After the mixed gas enters the atomizer 2, it atomizes the metal droplets. The thermal decomposition precursor is further heated on the surface of the metal droplets and undergoes a thermal decomposition reaction. The decomposition products coat or dope the surface of the metal droplets. The atomizer 2 is filled with preheated mixed gas, which impacts the metal flow and atomizes it. At the same time, the thermal decomposition precursor decomposes on the surface of the high-temperature droplets to generate a coating layer or doped material. The coated or doped metal droplets enter the atomization chamber 3 for cooling, and then the cooled metal powder is collected by the collection section. After the droplets enter the atomization chamber 3, the gas flow is accelerated by the blower 7, and the cyclone separator 8 performs staged cooling. Finally, the powder is collected by the first collection tank 9 and the second collection tank 10.

[0036] In some embodiments, the pyrolysis precursor includes at least one of the following: silicon-hydrogen gas (such as SiH4), hydrocarbon gas (such as CH4, C2H2, C2H4, etc.), or borohydride gas, ammonia, ammonia borane and its derivatives, boron trichloride, borazine, boron oxide, and sodium borohydride. The aforementioned precursor forms a functional coating layer or doped phase on the surface of the metal powder through a pyrolysis reaction, and is used to meet requirements for mechanical properties, laser absorption rate, insulation and thermal conductivity, electrical and thermal conductivity, wear resistance, etc.

[0037] In some embodiments, the first temperature is lower than the thermal decomposition temperature of the thermal decomposition precursor, and the range of the first temperature is between 100-800°C. The mixed gas is preheated to 100-800°C and then enters the atomizer. This temperature range is lower than the initial decomposition temperature of the thermal decomposition precursor, but higher than the ambient temperature, which can increase the kinetic energy of the gas and enhance the atomization shear efficiency. The thermal decomposition temperature is lower than the metal melting temperature, ensuring that the surface temperature of the metal droplet is sufficient to trigger the gas decomposition reaction, while the inside of the droplet remains in a molten state, providing sufficient thermal energy for the formation of the coating layer or doped phase.

[0038] In some embodiments, the metallic material includes at least one of titanium and titanium alloys, copper and copper alloys, aluminum and aluminum alloys, iron and iron alloys, and nickel and nickel alloys. These five material categories—titanium and titanium alloys, copper and copper alloys, aluminum and aluminum alloys, iron and iron alloys, and nickel and nickel alloys—cover the full range of needs, from high-strength structural components (titanium alloys), high-conductivity components (copper alloys), lightweight structural components (aluminum alloys), and low-cost structural components (iron alloys), to components resistant to extreme environments (high-temperature alloys), through complementary properties and process adaptation.

[0039] In some embodiments, the inert gas includes single gases such as argon, nitrogen, hydrogen, and helium, or mixtures thereof. The gas ratio can be flexibly adjusted according to material properties (such as melting point and oxidation tendency), and the mixed gas can improve process quality while reducing the cost of using single-element gases.

[0040] The same or similar parts between the various embodiments in this specification can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the method embodiments described later are relatively simple in description since they correspond to the system, and relevant parts can be referred to the descriptions in the system embodiments.

[0041] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A metal powder preparation apparatus, characterized in that, The device includes: A metal melting section, used for melting metal materials to obtain molten metal; The atomizing section is connected to the metal melting section. The atomizing section includes an atomizer, a gas supply section, and an atomizing chamber. The gas supply section is connected to the atomizer. The atomizer atomizes the molten metal that enters it. The gas supply section introduces inert gas and preheated thermal decomposition precursor into the atomizer so that the molten metal forms coated or doped metal powder during atomization. The atomized metal enters the atomizing chamber for cooling. The collection section is connected to the atomization chamber and collects the cooled metal powder.

2. The metal powder preparation apparatus according to claim 1, characterized in that, The gas supply unit includes a first gas storage tank, a second gas storage tank, and a preheating device. Both the first and second gas storage tanks are connected to the preheating device. The inert gas output from the first gas storage tank flows into the atomizer after passing through the preheating device, and the pyrolysis precursor output from the second gas storage tank flows into the atomizer after being heated by the preheating device.

3. The metal powder preparation apparatus according to claim 2, characterized in that, The preheating device uses one of the following methods for heating: induction heating, radiation heating, resistance heating, or plasma heating.

4. The metal powder preparation apparatus according to claim 1, characterized in that, The atomizing section also includes an induced draft fan and a cyclone separator. The induced draft fan is connected to the cyclone separator, and the cyclone separator is connected to the atomizing chamber, thereby enabling rapid cooling of the atomized metal droplets in the atomizing chamber to form coated or doped metal powder, and performing preliminary particle size classification on the product.

5. The metal powder preparation apparatus according to claim 4, characterized in that, The collection section includes a first collection tank and a second collection tank. The first collection tank is installed at the bottom of the cyclone separator, and the second collection tank is installed at the bottom of the atomization chamber.

6. A method for preparing metal powder, characterized in that, Applied to the apparatus as described in any one of claims 1-5, for preparing metal powders with high laser absorptivity and / or high flowability, comprising the following steps: The device is evacuated, and inert gas is introduced into the atomizer through the gas supply section to atmospheric pressure. The metal melting section melts the metal material to obtain metal droplets. The atomizer is filled with a mixture of inert gas and thermal decomposition precursor, which is preheated to the first temperature. After the mixed gas enters the atomizer, it atomizes the metal droplets. The thermal decomposition precursor is further heated on the surface of the metal droplets and undergoes a thermal decomposition reaction. The decomposition products are coated or doped on the surface of the metal droplets. The coated or doped metal droplets enter the atomization chamber for cooling, and then the cooled metal powder is collected by the collection section.

7. The method for preparing metal powder according to claim 6, characterized in that, The pyrolysis precursor includes at least one of the following: silicon hydrogen gas, hydrocarbon gas, boron hydrogen gas, ammonia, ammonia borane and its derivatives, boron trichloride, borazine, boron oxide, and sodium borohydride.

8. The method for preparing metal powder according to claim 7, characterized in that, The first temperature is lower than the thermal decomposition temperature of the thermal decomposition precursor, and the range of the first temperature is between 100-800℃.

9. The method for preparing metal powder according to claim 8, characterized in that, The metallic material includes at least one of titanium and titanium alloys, copper and copper alloys, aluminum and aluminum alloys, iron and iron alloys, nickel and nickel alloys, etc.

10. The method for preparing metal powder according to claim 6, characterized in that, The inert gas includes single gases such as argon, nitrogen, hydrogen, and helium, or mixtures thereof.

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