Ultrasonic atomization device for high melting point metal powder preparation

Abstract

The application discloses an ultrasonic atomization device for high-melting-point metal powder preparation, which comprises a variable amplitude rod, an atomization head and a heat sink, the atomization head is fixedly connected to one end of the variable amplitude rod, the heat sink is sleeved on the variable amplitude rod, and a heat exchange gap is formed between the heat sink and the back of the atomization surface of the atomization head and the outer circumferential surface of the variable amplitude rod, the heat sink is uniformly provided with cold medium inlet flow channels and hot medium outlet flow channels which are communicated with the heat exchange gap, and the cold medium inlet flow channels and the hot medium outlet flow channels are distributed at intervals. The ultrasonic atomization device can be used for the preparation of high-melting-point metal or alloy powder, the atomization head and the variable amplitude rod are cooled by continuously injecting the heat sink with cold medium circulation, the cold medium inlet flow channels and the hot medium outlet flow channels are distributed at intervals, the cold medium is rapidly cooled at each point of the atomization head and then discharged, so that the atomization head is cooled with high efficiency, the atomization head can resist high temperature and does not crack, and the service life of the atomization head is long.

Description

Technical Field

[0001] This invention relates to the field of ultrasonic atomization powder preparation technology, and more particularly to an ultrasonic atomization device for the preparation of high melting point metal powder. Background Technology

[0002] Ultrasonic atomization powder production technology is a highly efficient and low-consumption method for preparing fine metal powders. With the development of ultrasonic equipment, it has also experienced rapid growth in recent years. This technology uses ultrasound to atomize molten metal into powder, producing metal powders with good sphericity, controllable particle size, and a narrow particle size range, showing promising prospects in the metal powder production industry. The equipment used to prepare metal powders using ultrasonic atomization technology is called an ultrasonic powder maker, mainly composed of an ultrasonic generator, transducer, amplitude transformer, and atomizing head. The transducer converts high-frequency electrical oscillation signals into mechanical vibrations, transforming electrical energy into high-frequency vibrations. The amplitude transformer amplifies the displacement and velocity of the mechanical vibration particles, concentrating the ultrasonic energy over a small area. The atomizing head is the component in direct contact with the molten metal and is generally made of alloy. The transducer and amplitude transformer transmit high-frequency vibrations to the atomizing head, which then acts on the molten metal, atomizing it into fine particulate powder.

[0003] Common materials for atomizing heads include copper, stainless steel, high-strength steel, and high-strength titanium alloys. Currently, ultrasonic atomization technology is only suitable for preparing low-melting-point (melting point < 500℃) metal and alloy powders such as tin and tin alloys, and indium and indium alloy powders. If the goal is to prepare metal and alloy powders with higher melting points, the atomizing head in the ultrasonic atomizing device needs to maintain ultra-high-frequency vibration while also being subjected to the erosion effect of high-temperature molten metal. Under these dual effects, the atomizing head is prone to breakage and erosion by the molten metal, leading to atomization interruption and hindering production. To address these issues, existing solutions include directly using high-melting-point metals or alloys such as tungsten, niobium, and thallium as the atomizing head. However, this suffers from insufficient strength and difficulty in forming. Alternatively, a ceramic coating can be applied to the metal surface through a spraying process to increase the atomizing head's high-temperature resistance. However, the sprayed ceramic coating is not metallurgically bonded to the substrate, resulting in low bonding strength. Under high-frequency vibration, the coating is easily detached, failing to achieve the desired effect.

[0004] Therefore, improving the design of the atomizing head and amplitude transformer to ensure that they are not easily broken under high-frequency vibration and that the surface of the atomizing head can resist the erosion of high-temperature molten metal, in order to provide an ultrasonic atomizing device for preparing high-melting-point metal powder, is of great significance for the further application and expansion of ultrasonic atomizing technology in metal powder making. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes an ultrasonic atomization device for the preparation of high-melting-point metal powders, with the aim of enabling its use in the ultrasonic atomization preparation of high-melting-point metal powders.

[0006] The specific solution of this invention is as follows:

[0007] The present invention proposes an ultrasonic atomizing device for the preparation of high melting point metal powder, comprising an amplitude transformer, an atomizing head, and a heat sink. The atomizing head is fixedly connected to one end of the amplitude transformer, and the heat sink is fitted onto the amplitude transformer. A heat exchange gap is formed between the heat sink, the back of the atomizing surface of the atomizing head, and the outer peripheral surface of the amplitude transformer. The heat sink is uniformly provided with a cold medium inlet channel and a hot medium outlet channel that are connected to the heat exchange gap, and the cold medium inlet channel and the hot medium outlet channel are distributed at intervals.

[0008] Preferably, the base material of the atomizing head is a titanium alloy; preferably, the atomizing head has a textured structure, and the atomizing surface of the atomizing head also contains an in-situ generated ceramic layer.

[0009] The atomizing head of the present invention has a specific directional textured structure. The textured structure refers to the microstructure with certain regularity and certain size and distribution generated on the surface of the metal material. Moreover, the textured structure of the atomizing surface of the present invention is more densely arranged, which can improve the crack resistance of the atomizing head and make it less prone to cracking along the high-frequency vibration direction during ultrasonic powder making.

[0010] In a preferred embodiment, the atomizing surface also contains an in-situ generated ceramic layer. Since most molten metals have poor or no wettability with ceramics, and ceramics have a very high melting point, molten metals are unlikely to melt the ceramic layer on the atomizing head surface, thus ensuring the atomizing head remains unmelted and can continue to operate. Furthermore, the in-situ generated ceramic layer of this invention has high bonding strength with the substrate and will not detach during high-frequency vibration, increasing the service life of the atomizing head.

[0011] The high melting point metal powder mentioned in this invention refers to metal powder with a melting point between 500-1100℃.

[0012] Preferably, the ceramic layer is composed of titanium nitride or titanium oxide.

[0013] Preferably, the atomizing head is plastically deformed to form a textured structure within it; more preferably, after plastic deformation, laser nitriding or micro-arc oxidation is performed to generate a ceramic layer in situ on the atomizing surface.

[0014] Preferably, the radiator includes a disc portion and a sleeve portion, the disc portion being coaxially and integrally connected to one end of the sleeve portion, and the disc portion being attached to the back of the atomizing surface of the atomizing head.

[0015] Preferably, the cold medium inlet channel and the hot medium outlet channel are radially spaced on the disk portion, and the cold medium inlet channel and the hot medium outlet channel are axially spaced on the sleeve portion.

[0016] Preferably, the cold medium inlet channel and / or hot medium outlet channel located at the connection between the disc portion and the sleeve portion gradually increase in size from the outside to the inside.

[0017] Preferably, a branch channel is provided on the side wall between the cold medium inlet channel and the hot medium outlet channel. The inlet of the branch channel is located at the inner end of the inlet of the cold medium inlet channel and is directly opposite to the inlet of the cold medium inlet channel. The outlet of the branch channel is located on the inner wall of the hot medium outlet channel, and the branch channel has a meandering bend near its outlet.

[0018] Preferably, the branch channel is located at the tip of the inlet end of the side wall on the side where the cold medium enters the channel.

[0019] Preferably, the branch channel gradually increases in size from its bend to the outlet.

[0020] Preferably, the heat sink is made of aluminum or copper.

[0021] Preferably, sealing rings are installed at both ends of the heat exchange gap of the radiator.

[0022] The ultrasonic atomizing device of the present invention mainly achieves the synergistic effect of multiple aspects, making the atomizing head and the amplitude transformer less prone to breakage under high-frequency vibration, while the surface of the atomizing head can resist the erosion of high-temperature molten metal, and can be used for the preparation of metal or alloy powders with higher melting points of 500-1100℃.

[0023] The synergistic effect is mainly manifested in the following aspects: (1) The atomizing head and the amplitude transformer are cooled by continuously injecting cold medium into the radiator. The cold medium is distributed at intervals into the flow channel and the hot medium is discharged from the flow channel, so that the cold medium can quickly complete the heat exchange at each point of the atomizing head and then be discharged, thereby efficiently cooling the atomizing head; (2) The atomizing head substrate has a specific directional texture structure, which improves the strength of the matrix material. The texture structure of the atomizing surface of the atomizing head is more densely arranged, so that the frequency transformer and the atomizing head are not easy to break under high frequency vibration; (3) Furthermore, a ceramic layer is generated in situ on the atomizing surface with texture structure. The ceramic layer can withstand high temperature and corrosion. It is formed in situ on the surface of the matrix material. It belongs to metallurgical bonding, has high bonding strength, does not crack under high temperature liquid metal and ultrasonic high frequency vibration, and does not bond or react with most high melting point metals. Attached Figure Description

[0024] Figure 1 This is a cross-sectional schematic diagram of an ultrasonic atomizing device for preparing high-melting-point metal powder as presented in the embodiments.

[0025] Figure 2 for Figure 1 A partial structural diagram of the ultrasonic atomizing device in the diagram. 。 Detailed Implementation

[0026] Please refer to Figure 1-2 As shown, an ultrasonic atomizing device for preparing high-melting-point metal powder according to an embodiment of the present invention includes an amplitude transformer 1, an atomizing head 2, and a radiator 3. The atomizing head 2 is fixedly connected to one end of the amplitude transformer 1. The radiator 3 is fitted onto the amplitude transformer 1, and a heat exchange gap 4 is formed between the radiator 3, the back of the atomizing surface of the atomizing head 2, and the outer peripheral surface of the amplitude transformer 1. A cold medium inlet channel 5 and a hot medium outlet channel 6, which are connected to the heat exchange gap 4, are uniformly arranged on the radiator 3, and the cold medium inlet channel 5 and the hot medium outlet channel 6 are distributed at intervals.

[0027] In this embodiment, the cold medium inlet channel 5 and the hot medium outlet channel 6 of the radiator 3 can be connected to the cold medium circulation and transportation system through pipelines. Here, the cold medium refers to cold air or coolant, that is, the radiator 3 can be circulated with coolant or cold air for heat dissipation. The radiator 3 is made of aluminum or copper, and sealing rings 8 are installed at both ends of the heat exchange gap 4 of the radiator 3. The sealing rings 8 are made of high-temperature resistant graphite.

[0028] When the ultrasonic atomizing device is working, such as Figure 1 As shown, the upper surface of the atomizing head 2 is the surface in contact with the molten metal, which is the atomizing surface. The transducer of the ultrasonic device transmits high-frequency vibrations to the atomizing head 2 through the amplitude transformer 1, generating high-frequency ultrasonic vibrations on the atomizing surface. The vibration peaks formed by the amplitude separate and break the droplets from the surface. As the frequency of the ultrasonic waves gradually increases, the generated atomized droplets become finer and finer. Under the continuous action of the ultrasonic vibration frequency, fine metal powder particles can eventually be obtained.

[0029] The process of ultrasonic atomization to produce metal powder can be roughly divided into two stages: crushing and condensation. Crushing generates molten metal droplets and affects the size of the final metal powder. Condensation determines the formation of the final metal particles and directly affects the shape of the metal powder. Therefore, the device uses a heat sink 3 to dissipate heat from the atomizing head 2 and the amplitude transformer 1. The purpose is to continuously reduce the surface temperature of the atomizing head 2, which ensures the condensation effect of the metal droplets and protects the atomizing head 2 from cracking, thus extending its service life.

[0030] Reference Figure 1Because the cold medium inlet channel 5 and the hot medium outlet channel 6 on the radiator 3 are distributed alternately, the cold medium enters and exits evenly from all positions. The time spent in the heat exchange gap 4 is short. The cold medium continuously contacts the surface of the atomizing head 2 and the amplitude rod 1, and quickly removes heat, so that the heat dissipation efficiency is greatly improved, which can meet the needs of the atomizing head 2 to prepare high melting point (500-1100℃) metal powder.

[0031] In this embodiment, the radiator 3 includes a disc portion 31 and a sleeve portion 32. The disc portion 31 is coaxially and integrally connected to one end of the sleeve portion 32, which is located on the outer periphery of the amplitude transformer 1. The disc portion 31 is attached to the back side of the atomizing surface of the atomizing head 2. The radiator 3, composed of the disc portion 31 and the sleeve portion 32, has a small wall thickness, resulting in low heat storage capacity. This ensures minimal impact on heat exchange between the cold medium and the atomizing head 2 and amplitude transformer 1. Simultaneously, this maximizes the utilization of the space surrounding the radiator 3, facilitating the arrangement of connecting cold medium circulation pipelines.

[0032] In the radiator 3, which consists of a disc portion 31 and a sleeve portion 32, the cold medium inlet channel 5 and the hot medium outlet channel 6 are radially spaced on the disc portion 31, and axially spaced on the sleeve portion 32. This is a preferred embodiment, which ensures that the channels are uniformly and densely distributed.

[0033] In addition, the connection between the disc portion 31 and the sleeve portion 32 may be provided with a cold medium inlet channel 5 or a hot medium outlet channel 6, or both channels. The disc portion 31 and the sleeve portion 32 form a 90° bend, and the cold medium inlet channel 5 and / or the hot medium outlet channel 6 at the connection portion are designed to gradually increase in size from the outside to the inside.

[0034] In actual operation, the cold medium entering through the cold medium inlet channel 5 will be affected by the hot medium discharged through the hot medium outlet channel 6, which has already undergone heat exchange. This causes the cold medium to undergo preliminary heat exchange with the heat sink 3 itself before it even enters the heat exchange gap 4, thus affecting the heat dissipation efficiency of the atomizing head 2.

[0035] Therefore, in a further embodiment, a branch channel 7 is provided on the side wall between the cold medium inlet channel 5 and the hot medium outlet channel 6. The inlet of the branch channel 7 is located at the inner end of the inlet of the cold medium inlet channel 5 and is directly opposite to the inlet of the cold medium inlet channel 5. The outlet of the branch channel 7 is located on the inner wall of the hot medium outlet channel 6, and the branch channel 7 has a meandering bend 71 near its outlet.

[0036] As a preferred embodiment, the inlet end of the branch channel 7 on the side wall of the cold medium inlet channel 5 is pointed. This is to facilitate the diversion of the cold medium when it enters from the cold medium inlet channel 5, thereby reducing the resistance generated by the side wall of the branch channel 7. The branch channel 7 gradually increases in size from its meandering bend 71 to the outlet, which can accelerate the entry of the cold medium from the branch channel 7 into the hot medium outlet channel 6.

[0037] like Figure 2 As shown, the arrows indicate the flow direction of the medium. A portion of the cold medium entering the cold medium in the inlet channel 5 flows into the branch channel 7, and then from the branch channel 7 into the hot medium outlet channel 6 before being discharged together. The instantaneous temperature of this portion of cold medium that does not enter the heat exchange gap 4 is lower than the instantaneous temperature of the hot medium in the hot medium outlet channel 6, thus neutralizing the temperature difference and reducing the instantaneous temperature difference between the hot medium outlet channel 6 and the cold medium inlet channel 5. This reduces the efficiency of heat exchange through the wall thickness between the hot medium outlet channel 6 and the cold medium inlet channel 5, significantly reducing the temperature impact of the hot medium outlet channel 6 on the cold medium inlet channel 5, ensuring better heat dissipation for the cold medium entering the radiator 3.

[0038] In addition to the above improvements to the structure of the ultrasonic atomizing device, this invention also optimizes the material of the atomizing head and explores the influence of the atomizing head material and structure on the performance of the ultrasonic atomizing device, as detailed below:

[0039] As a preferred embodiment, an ultrasonic atomizing device includes an amplitude transformer 1, an atomizing head 2, and a radiator 3. The atomizing head 2 is fixedly connected to one end of the amplitude transformer 1, and the radiator 3 is fitted onto the amplitude transformer 1. A heat exchange gap 4 is formed between the radiator 3, the back of the atomizing surface of the atomizing head 2, and the outer peripheral surface of the amplitude transformer 1. A cold medium inlet channel 5 and a hot medium outlet channel 6, which are connected to the heat exchange gap 4, are uniformly arranged on the radiator 3, and the cold medium inlet channel 5 and the hot medium outlet channel 6 are distributed at intervals.

[0040] The atomizing head 2 is made of titanium alloy as its base material and has a textured structure, which is formed by plastic deformation of the base material under pressure to create a textured structure with a specific direction.

[0041] As a preferred embodiment, the basic structure of an ultrasonic atomizing device is the same as that of preferred embodiment one, except that the substrate material of the atomizing head 2 is titanium alloy, the atomizing head 2 has a textured structure, and the atomizing surface also contains an in-situ generated ceramic layer 21, which is obtained by laser processing after plastic deformation of the atomizing head 2.

[0042] As a comparative option one, the basic structure of the ultrasonic atomizing device is the same as that of the preferred option one, the only difference being that the atomizing head 2 is made of titanium alloy and does not contain ceramic layer 21 or textured structure.

[0043] As a comparative option two, an ultrasonic atomizing device includes an amplitude transformer 1 and an atomizing head 2; the atomizing head 2 is fixedly connected to one end of the amplitude transformer 1; wherein, the base material of the atomizing head 2 is titanium alloy, which does not contain a ceramic layer 21 or a textured structure.

[0044] High-melting-point alloys were prepared using ultrasonic atomization devices of preferred scheme one, preferred scheme two, and comparative schemes one and two, respectively, and the stability of the ultrasonic atomization devices was tested. The results are shown in Table 1 below:

[0045] Table 1 Stability test results

[0046]

[0047] Note: The melting point of aluminum-based brazing material AlSi12 is 588℃; the melting point of cold storage material HoCu2 is 860℃; and the melting point of nickel-based brazing material BNi-2 is 1000℃. In preferred schemes one and two, the cumulative 80h refers to the period during which the atomizing head does not crack or stick to materials after 80 hours of cumulative powder production using this device.

[0048] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An ultrasonic atomizing device for preparing high-melting-point metal powder, characterized in that, The device includes an amplitude transformer (1), an atomizing head (2), and a radiator (3). The atomizing head (2) is fixedly connected to one end of the amplitude transformer (1). The radiator (3) is fitted onto the amplitude transformer (1). A heat exchange gap (4) is formed between the radiator (3), the back of the atomizing surface of the atomizing head (2), and the outer peripheral surface of the amplitude transformer (1). The radiator (3) is uniformly provided with a cold medium inlet channel (5) and a hot medium outlet channel (6) that are connected to the heat exchange gap (4). The cold medium inlet channel (5) and the hot medium outlet channel (6) are distributed at intervals. A branch channel (7) is provided on the side wall between the cold medium inlet channel (5) and the hot medium outlet channel (6). The inlet of the branch channel (7) is located at the inner end of the inlet of the cold medium inlet channel (5) and is directly opposite to the inlet of the cold medium inlet channel (5). The outlet of the branch channel (7) is located on the inner wall of the hot medium outlet channel (6), and the branch channel (7) has a meandering bend (71) near its outlet. The branch channel (7) is located on the side wall of the cold medium entering the channel (5) with one end of the inlet pointed. The base material of the atomizing head (2) is titanium alloy; the atomizing head has a textured structure, and the atomizing surface of the atomizing head also contains an in-situ generated ceramic layer (21).

2. The ultrasonic atomizing device for preparing high-melting-point metal powder according to claim 1, characterized in that, The ceramic layer (21) is composed of titanium nitride or titanium oxide.

3. The ultrasonic atomizing device for preparing high-melting-point metal powder according to claim 2, characterized in that, Plastic deformation is performed on the atomizing head (2) to form a textured structure in the atomizing head.

4. The ultrasonic atomizing device for preparing high-melting-point metal powder according to claim 3, characterized in that, After plastic deformation, laser nitriding or micro-arc oxidation is performed to generate a ceramic layer in situ on the atomized surface (21).

5. The ultrasonic atomizing device for preparing high-melting-point metal powder according to claim 1, characterized in that, The radiator (3) includes a disc part (31) and a sleeve part (32). The disc part (31) is coaxially and integrally connected to one end of the sleeve part (32). The disc part (31) is attached to the back of the atomizing surface of the atomizing head (2).

6. The ultrasonic atomizing device for preparing high-melting-point metal powder according to claim 5, characterized in that, The cold medium inlet channel (5) and the hot medium outlet channel (6) are radially spaced on the disc portion (31), and the cold medium inlet channel (5) and the hot medium outlet channel (6) are axially spaced on the sleeve portion (32).

7. The ultrasonic atomizing device for preparing high-melting-point metal powder according to claim 6, characterized in that, The cold medium inlet channel (5) and / or hot medium outlet channel (6) located at the connection between the disc part (31) and the sleeve part (32) gradually increase in size from the outside to the inside.

8. The ultrasonic atomizing device for preparing high-melting-point metal powder according to claim 1, characterized in that, The branch channel (7) gradually increases in size from its meandering bend (71) to the outlet.

9. The ultrasonic atomizing device for preparing high-melting-point metal powder according to any one of claims 5-8, characterized in that, The heat sink (3) is made of aluminum or copper.

10. The ultrasonic atomizing device for preparing high-melting-point metal powder according to any one of claims 5-8, characterized in that, Sealing rings (8) are installed at both ends of the heat exchange gap (4) of the radiator (3).

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