Powder production apparatus and powder production method

Abstract

To provide a powder production apparatus and a powder production method that are able to effectively reduce the particle size of particles obtained.SOLUTION: Rotating means 12 is provided such that an elongated rod-like member 11, having at least one end 11a made of a metal or an alloy, is rotatable about a central axis along its longitudinal direction. Laser irradiation means 13 is provided to make it possible to irradiate an end face 11c on the side of the one end 11a with a laser and thereby heat and melt the one end 11a of the rod-like member 11 that rotates by the rotating means 12.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a powder manufacturing apparatus and a powder manufacturing method. [Background technology]

[0002] The plasma rotating electrode method has been used as one of the conventional methods for producing spherical metal or alloy powder particles. In the plasma rotating electrode method, a long and thin electrode member made of a metal or alloy is rotated around a central axis along its length, and plasma is irradiated toward the tip of the rotating electrode member to melt the tip of the electrode member, and the resulting melt is blown away and solidified by the centrifugal force of the rotation of the electrode member, thereby producing spherical metal or alloy powder particles (see, for example, Non-Patent Documents 1 to 3).

[0003] In this conventional plasma rotating electrode method, when plasma is irradiated onto the tip of the electrode member, a molten pool is formed in the center of the tip surface of the electrode member, and it is thought that this molten pool gradually deepens, causing the droplets that separate from the molten pool to become larger. Therefore, in order to obtain particles with smaller diameters, the present inventors have proposed a device that cools the side surface of the tip of the electrode member to prevent the molten pool from becoming deeper and causing the droplets that separate from the molten pool to become larger (see, for example, Patent Document 1).

[0004] However, when the inventors simulated the powder production process under various conditions using the conventional plasma rotating electrode method, they showed that the particle size of the obtained particles becomes smaller and more refined when the tip surface of the electrode member that irradiates the plasma is recessed rather than when the tip surface is flat (see, for example, Non-Patent Documents 4 or 5). [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Koji Kakei, Rei Yokomori, Tomohiro Nishimaki, "Microstructure and Strength of Powder Sintered Nickel Superalloys Produced by Plasma Rotating Electrode Method", Journal of the Japan Institute of Metals, Vol. 80, No. 8, 2016, pp. 508-514 [Non-patent document 2] Masaharu Tokizane and Kazuo Isonishi, "Production of Ti Alloy Powder by Plasma Rotating Electrode Method," Resource Processing Technology, 1990, Vol. 37, No. 4, pp. 215-221 [Non-patent document 3] Ryohei Kumagai, "Preparation of Metallic Spherical Powders by Plasma Rotating Electrode Method," Materia, 1998, Vol. 37, No. 6, pp. 488-494 [Non-patent document 4] Yufan Zhao, Yujie Cui, Haruko Numata, Huakang Bian, Kimio Wako, Kenta Yamanaka, Kenta Aoyagi and Akihiko Chiba, “Centrifugal granulation behavior in metallic powder fabrication by plasma rotating electrode process”, Scientific Reports, [online], 2020, Internet〈URL: https: / / doi.org / 10.1038 / s41598-020-75503-w〉 [Non-Patent Document 5] Yujie Cui, Yufan Zhao, Haruko Numata, Kenta Yamanaka, Huakang Bian, Kenta Aoyagi and Akihiko Chiba, “Effects of process parameters and cooling gas on powder formation during the plasma rotating electrode process”, Powder Technology, November 2021, Vol.393, p.301-311 [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-183711 Summary of the Invention [Problem to be solved by the invention]

[0007] According to Non-Patent Documents 4 and 5, in the conventional plasma rotating electrode method, the particle size of the obtained particles becomes smaller and more refined when the tip surface of the electrode member to which the plasma is irradiated is recessed. However, since it is difficult to control the distribution of energy density in plasma irradiation, it is difficult to control the melting rate of the tip surface of the electrode member and the shape of the recess on the tip surface, and there is a problem that it is difficult to effectively reduce the particle size of the obtained particles.

[0008] The present invention has been made in light of the above-mentioned problems, and has as its object to provide a powder production apparatus and a powder production method that can effectively reduce the particle size of the resulting particles. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, the powder manufacturing apparatus of the present invention is characterized by having a rod-shaped member that is elongated and has at least one end made of metal or alloy, a rotation means that is arranged to rotate the rod-shaped member around a central axis along the length direction, and a laser irradiation means that is arranged to irradiate a laser toward the end face on the one end side of the rod-shaped member that is rotated by the rotation means so as to heat and melt the one end.

[0010] The powder production method according to the present invention is characterized in that a long, thin rod-shaped member having at least one end made of a metal or alloy is rotated around a central axis along the lengthwise direction, and a laser is irradiated toward the end face of the rotating rod-shaped member on the side of the one end to heat and melt the one end of the rod-shaped member, and the resulting molten liquid is blown away by the centrifugal force of the rotation of the rod-shaped member, thereby producing a powder made of a metal or alloy.

[0011] The powder production method according to the present invention can be suitably implemented by the powder production apparatus according to the present invention. The powder production apparatus and powder production method according to the present invention can heat and melt one end of a rotating rod-shaped member by irradiating a laser toward the end face on one end of the rod-shaped member. Since a laser can more accurately control the distribution of energy density than a plasma heat source, it is possible to more accurately control the melting rate of the end face on one end of the rod-shaped member. This makes it possible to optimize conditions such as the melting rate to further reduce the particle size of the resulting particles, thereby effectively reducing the particle size of the resulting particles.

[0012] The powder production apparatus and method according to the present invention can optimize conditions such as the melting rate of one end surface of a rod-shaped member by adjusting, for example, the laser output, spot size, intensity distribution, scanning speed, scanning method, etc. Furthermore, in the powder production apparatus and method according to the present invention, the rod-shaped member may be made of any metal or alloy having the composition of the particles to be produced, such as carbon steel, stainless steel, tool steel, pure copper, or aluminum alloy. In this case, it is preferable to change the type of laser used depending on the material of the rod-shaped member; for example, a visible light laser may be used for rod-shaped members made of pure copper or aluminum alloy.

[0013] In the powder manufacturing apparatus according to the present invention, the laser irradiation means is preferably configured to irradiate the laser so that the end face is recessed toward the other end of the rod-shaped member. In the powder manufacturing method according to the present invention, the laser is preferably irradiated so that the end face is recessed toward the other end of the rod-shaped member. In these cases, not only can the melting rate of the end face on one end side of the rod-shaped member be controlled accurately, but also the shape of the recess on that end face can be controlled with high precision. Therefore, the conditions for the recess shape can be optimized to further reduce the particle size of the resulting particles, thereby more effectively reducing the particle size of the resulting particles.

[0014] The powder manufacturing apparatus according to the present invention preferably has a chamber, at least one end of the rod-shaped member is disposed inside the chamber, and the laser irradiation means is configured to irradiate the laser toward the end face of the rod-shaped member inside the chamber. The powder manufacturing method according to the present invention preferably has at least one end of the rod-shaped member disposed inside the chamber, and irradiates the laser toward the end face of the rod-shaped member at the end of the rod-shaped member inside the chamber. In these cases, the powder particles produced can be prevented from oxidizing by filling the interior of the chamber with an inert gas such as Ar, He, or N2.

[0015] In the powder production apparatus according to the present invention, the laser irradiation means may be, for example, a laser having a Gaussian intensity distribution in a plane perpendicular to the optical axis, a laser having a ring-shaped intensity distribution in a plane perpendicular to the optical axis, or a flat-top laser having a constant intensity distribution at the center in a plane perpendicular to the optical axis. The powder production method according to the present invention may be, for example, a laser having a Gaussian intensity distribution in a plane perpendicular to the optical axis, a laser having a ring-shaped intensity distribution in a plane perpendicular to the optical axis, or a flat-top laser having a constant intensity distribution at the center in a plane perpendicular to the optical axis. In these cases, the energy density distribution can be precisely controlled in accordance with the characteristics of each laser, and conditions such as the melting rate and depression shape can be optimized to reduce the particle size of the resulting particles. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a powder production apparatus and a powder production method that can effectively reduce the particle size of the resulting particles. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a perspective view showing a state in which a powder manufacturing apparatus according to an embodiment of the present invention is used. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a powder manufacturing apparatus and a powder manufacturing method according to an embodiment of the present invention. As shown in FIG. 1, a powder manufacturing apparatus 10 according to an embodiment of the present invention includes a chamber (not shown), a rod-shaped member 11, a rotating means 12, and a laser irradiation means 13.

[0019] The chamber is configured so that it can be filled with an inert gas such as Ar, He, or N2. The chamber may be made of a material used in a plasma rotating electrode method. The rod-shaped member 11 has a long, thin round rod shape. The rod-shaped member 11 is made of a metal or alloy, and is made of the composition of the particles to be produced, such as carbon steel, stainless steel, tool steel, pure copper, or aluminum alloy. One end 11a of the rod-shaped member 11 is located inside the chamber, and the other end 11b is located outside the chamber.

[0020] The rotating means 12 is disposed outside the chamber and connected to the other end 11b of the rod-shaped member 11 so as to be able to rotate the rod-shaped member 11 around a central axis along the length direction. The rotating means 12 may be one used to rotate an electrode member in a plasma rotating electrode method.

[0021] The laser irradiation means 13 is provided inside the chamber so as to be able to irradiate a laser beam toward the end face 11c on the side of one end 11a of the rod-shaped member 11. The laser irradiation means 13 is configured so as to heat and melt the end face 11c of the rod-shaped member 11 rotated by the rotation means 12, and to irradiate the end face 11c with a laser beam so as to recess the end face 11c toward the other end 11b of the rod-shaped member 11. The laser irradiation means 13 is configured so as to be able to finely adjust the output, spot size, intensity distribution, scanning speed, scanning method, etc. The laser irradiation means 13 may be of any type as long as these parameters are finely adjustable. For example, the laser irradiation means 13 may be configured to irradiate a laser beam having a Gaussian intensity distribution in a plane perpendicular to the optical axis, a laser beam having a ring-shaped intensity distribution in a plane perpendicular to the optical axis, or a flat-top type laser beam having a constant intensity distribution at the center in a plane perpendicular to the optical axis.

[0022] The powder production method according to the embodiment of the present invention can be suitably implemented by a powder production apparatus 10. The powder production method according to the embodiment of the present invention can produce powder as follows. First, the chamber is filled with an inert gas, such as Ar, He, or N, to prevent oxidation of the powder particles to be produced. Next, the rotating means 12 rotates the rod-shaped member 11 around its central axis along its length. The laser irradiation means 13 irradiates a laser beam toward the end face 11c on the side of one end 11a of the rotating rod-shaped member 11 inside the chamber. The laser is irradiated so that the end face 11c of the rod-shaped member 11 is recessed toward the other end 11b of the rod-shaped member 11. The laser irradiation heats and melts the one end 11a of the rod-shaped member 11. The molten liquid is blown away and solidified by the centrifugal force of the rotation of the rod-shaped member 11, producing spherical metal or alloy powder.

[0023] In the powder production apparatus 10 and powder production method according to the embodiment of the present invention, a laser can more accurately control the energy density distribution than a plasma heat source, and therefore it is possible to more accurately control the melting rate and the shape of the depression on the end face 11c on one end 11a side of the rod-shaped member 11. This makes it possible to optimize conditions such as the melting rate and the shape of the depression in order to reduce the particle size of the resulting particles, thereby effectively reducing the particle size of the resulting particles.

[0024] The powder production apparatus 10 and powder production method according to the embodiment of the present invention can optimize conditions such as the melting rate and depression shape of the end face 11c on one end 11a side of the rod-shaped member 11 by adjusting, for example, the laser output, spot size, intensity distribution, scanning speed, scanning method, etc. Furthermore, because the energy density distribution can be precisely controlled in accordance with the characteristics of the laser used, it is possible to optimize conditions such as the melting rate and depression shape to further reduce the particle size of the resulting particles.

[0025] In the powder manufacturing apparatus 10 and powder manufacturing method according to the embodiment of the present invention, the particle size of the resulting particles can be further reduced effectively by changing the type of laser used depending on the material of the rod-shaped member 11, for example, by using a visible light laser for a rod-shaped member 11 made of pure copper or an aluminum alloy. [Explanation of symbols]

[0026] 10 Powder manufacturing equipment 11 Rod-shaped member 11a One end 11b The other end 11c (end face on one end 11a side) 12 Rotation means 13 Laser irradiation means

Claims

1. a rod-shaped member having an elongated shape and at least one end made of a metal or alloy; a rotating means for rotating the rod-shaped member around a central axis along the length direction; a laser irradiation means provided to be able to irradiate a laser toward an end face of the one end of the rod-shaped member rotated by the rotation means so as to heat and melt the one end of the rod-shaped member; A powder manufacturing apparatus comprising:

2. 2. The powder manufacturing apparatus according to claim 1, wherein the laser irradiation means is configured to irradiate the laser so that the end face is recessed toward the other end of the rod-shaped member.

3. a chamber; At least one end of the rod-shaped member is disposed inside the chamber, the laser irradiation means is provided inside the chamber so as to be able to irradiate the laser toward the end face of the rod-shaped member.

3. The powder manufacturing apparatus according to claim 1 or 2.

4. 2. The powder manufacturing apparatus according to claim 1, wherein the laser irradiation means is one that irradiates a laser having a Gaussian intensity distribution in a plane perpendicular to the optical axis, one that irradiates a laser having a ring-shaped intensity distribution in a plane perpendicular to the optical axis, or one that irradiates a flat-top type laser having a constant intensity distribution at the center in a plane perpendicular to the optical axis.

5. A powder production method comprising: rotating a thin, rod-shaped member having at least one end made of a metal or alloy around a central axis along the length; irradiating a laser toward the end face of the rotating rod-shaped member on the side of the one end to heat and melt the one end of the rod-shaped member; and blowing away the molten liquid by the centrifugal force of the rotation of the rod-shaped member, thereby producing a powder made of a metal or alloy.

6. 6. The method for producing powder according to claim 5, wherein the laser is irradiated so that the end face is recessed toward the other end of the rod-shaped member.

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