Method for producing aluminum-containing particles

Abstract

The present invention provides a method for producing aluminum-containing particles, which can narrow the particle size distribution of the obtained aluminum-containing particles. [Solution] A method for producing aluminum-containing particles, comprising: a step (A) of obtaining aluminum-containing particles (a) by an atomization method; and a step (B) of classifying the aluminum-containing particles (a) to obtain aluminum-containing particles (b), wherein the oxygen concentration in the atmosphere in the step (A) is 4,500 ppm or less.

Description

Technical Field

[0001] The present invention relates to a method for producing aluminum-containing particles.

Background Art

[0002] As a technology related to aluminum-containing particles, for example, the technology described in Patent Document 1 is known.

[0003] Patent Document 1 describes particles containing an aluminum alloy, which are substantially spherical in the state of primary particles and have a mixed phase of a phase represented by M x Al y and a phase represented by M z Al w where M is a metal other than Al, 0 < x < 1, 0 < y < 1, 0 < z < 1, 0 < w < 1, x / y ≧ 1, z / w < 1, x + y = 1, z + w = 1, and the aluminum content is in the range of 8 mass% to 50 mass%. According to the particles described in Patent Document 1, it is described that particles having a mixed phase of two types of aluminum alloys can be provided in the form of primary particles.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention provides a method for producing aluminum-containing particles capable of making the particle size distribution of the obtained aluminum-containing particles narrower.

Means for Solving the Problems

[0006] According to the present invention, a method for producing aluminum-containing particles shown below is provided.

[0007] [1] A step (A) of obtaining aluminum-containing particles (a) by an atomization method; and a step (B) of classifying the aluminum-containing particles (a) to obtain aluminum-containing particles (b), The method for producing aluminum-containing particles, wherein the oxygen concentration in the atmosphere in the step (A) is 4500 ppm or less. [2] The method for producing aluminum-containing particles according to [1] above, wherein the atomization method is a disk atomization method. [3] The method for producing aluminum-containing particles according to [2] above, wherein in the step (A), the rotation speed of the rotating disk is 50,000 rpm or more and 110,000 rpm or less. [4] The method for producing aluminum-containing particles according to any one of the above [1] to [3], further comprising a step (C) of classifying the aluminum-containing particles (b) after the step (B). [5] The aluminum-containing particles are calculated by the following <particle size measurement>. 50 The method for producing aluminum-containing particles according to any one of the above [1] to [4], wherein the particle diameter is 30.0 μm or more and 60.0 μm or less. <Particle size measurement> 3.0 g of aluminum-containing particles were mixed with 40 mL of water and 10 mL of a 1.3% surfactant, and the mixture was dispersed in an ultrasonic bath for 300 seconds to obtain a measurement sample. The volume-based particle size distribution of the aluminum-containing particles was measured using a laser diffraction / scattering particle size measurement device, and D 10 Particle size, D 50 Particle size and D 90 The particle size values ​​are obtained respectively. [6] The aluminum-containing particles are calculated by the following <particle size measurement>. 10 The method for producing aluminum-containing particles according to any one of the above [1] to [5], wherein the particle diameter is 20.0 μm or more and 40.0 μm or less. <Particle size measurement> 3.0 g of aluminum-containing particles were mixed with 40 mL of water and 10 mL of a 1.3% surfactant, and the mixture was dispersed in an ultrasonic bath for 300 seconds to obtain a measurement sample. The volume-based particle size distribution of the aluminum-containing particles was measured using a laser diffraction / scattering particle size measurement device, and D 10 Particle size, D 50 Particle size and D 90 The particle size values ​​are obtained respectively. [7] The aluminum-containing particles are calculated by the following <particle size measurement>. 90 The method for producing aluminum-containing particles according to any one of the above [1] to [6], wherein the particle diameter is 50.0 μm or more and 100.0 μm or less. <Particle size measurement> 3.0 g of aluminum-containing particles were mixed with 40 mL of water and 10 mL of a 1.3% surfactant, and the mixture was dispersed in an ultrasonic bath for 300 seconds to obtain a measurement sample. The volume-based particle size distribution of the aluminum-containing particles was measured using a laser diffraction / scattering particle size measurement device, and D 10 Particle size, D 50 Particle size and D 90 The particle size values ​​are obtained respectively. [8] The aluminum-containing particles are calculated by the following <particle size measurement>. 90 Particle diameter is D 10 The method for producing aluminum-containing particles according to any one of the above [1] to [7], wherein the value divided by the particle diameter is 1.5 or more and 4.0 or less. <Particle size measurement> 3.0 g of aluminum-containing particles were mixed with 40 mL of water and 10 mL of a 1.3% surfactant, and the mixture was dispersed in an ultrasonic bath for 300 seconds to obtain a measurement sample. The volume-based particle size distribution of the aluminum-containing particles was measured using a laser diffraction / scattering particle size measurement device, and D 10 Particle size, D 50 Particle size and D 90 The particle size values ​​are obtained respectively. [9] The aluminum-containing particles include aluminum-containing particles (A) having no satellite particles and aluminum-containing particles (B) having satellite particles, The method for producing aluminum-containing particles according to any one of the above [1] to [8], wherein the content of the aluminum-containing particles (B) having satellite particles, calculated by the following <Method 1>, is 90% or less. <Method 1> The aluminum-containing particles are observed using a scanning electron microscope, and the ratio of the number of aluminum-containing particles (B) having satellite particles to the total number of aluminum-containing particles observed is defined as the content of aluminum-containing particles (B) having satellite particles.

[10] The method for producing aluminum-containing particles according to any one of [1] to [9] above, wherein the aluminum-containing particles have a sphericity of 0.8 or more.

[11] The method for producing aluminum-containing particles according to any one of the above [1] to

[10] , wherein the aluminum-containing particles include at least one selected from the group consisting of pure aluminum particles and aluminum-based alloy particles.

[12] The method for producing aluminum-containing particles according to

[11] , wherein the aluminum-based alloy particles contain at least one element selected from the group consisting of Cu, Mn, Si, Mg, Zn, and Ni.

[13] The method for producing aluminum-containing particles according to

[11] or

[12] above, wherein the aluminum-based alloy particles contain at least one selected from the group consisting of an Al-Si based alloy, an Al-Cu based alloy, an Al-Mn based alloy, an Al-Mg based alloy, an Al-Si-Mg based alloy, an Al-Si-Cu based alloy, an Al-Zn-Mg based alloy, an Al-Si-Mg-Cu based alloy, an Al-Cu-Ni-Mg based alloy, and an Al-Zn-Mg-Cu based alloy.

[14] The method for producing aluminum-containing particles according to any one of the above

[11] to

[13] , wherein the aluminum-based alloy particles contain at least one selected from the group consisting of AlSi10Mg and AlSi12.

[15] The method for producing aluminum-containing particles according to any one of [1] to

[14] above, wherein the aluminum-containing particles can be used as a raw material powder for objects molded by 3D printers. Effect of the Invention

[0008] According to the present invention, there can be provided a method for producing aluminum-containing particles that can narrow the particle size distribution of the obtained aluminum-containing particles. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a diagram showing a schematic diagram of an example of a cross section of an aluminum-containing particle (B) having satellite particles. [Diagram 2] 1 is an SEM image of an aluminum-containing particle for explaining a method for determining particle (A) and particle (B). [Diagram 3] 1 is an SEM image of an aluminum-containing particle for explaining a method for determining particle (A) and particle (B). [Figure 4] 1 is an SEM image of an aluminum-containing particle for explaining a method for determining particle (A) and particle (B). [Diagram 5] 1 is a SEM image of the aluminum-containing particles of Example 5. [Figure 6] FIG. 6 is a diagram with reference numbers added to FIG. 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the drawings are simplified and do not correspond to the actual dimensional ratio. Numerical ranges "A to B" indicate A or more and B or less unless otherwise specified. In this specification, "aluminum-containing particles (A) having no satellite particles" may be abbreviated as "particles (A)". Similarly, "aluminum-containing particles (B) having satellite particles" may be abbreviated as "particles (A)".

[0011] [Method of manufacturing aluminum-containing particles] The method for producing aluminum-containing particles of the present embodiment includes a step (A) of obtaining aluminum-containing particles (a) by an atomization method, and a step (B) of classifying the aluminum-containing particles (a) to obtain aluminum-containing particles (b), wherein the oxygen concentration in the atmosphere in the step (A) is 4500 ppm or less.

[0012] The aluminum-containing particles are used, for example, as raw material powder for objects made by 3D printers, solder paste powder, etc.

[0013] There is a demand for improved modeling accuracy in raw powders used for 3D printer models. The present inventors have found that an increase in the number of irregular-shaped particles contained in the aluminum-containing particles raises concerns about a decrease in modeling accuracy due to the occurrence of defects inside an object obtained by a 3D printer, the manifestation of unevenness on the surface of the object obtained, etc. In other words, the present inventors have considered that the modeling accuracy of the object obtained can be improved by reducing the number of irregular-shaped particles contained in the aluminum-containing particles.

[0014] Furthermore, according to the study by the present inventors, when the number of irregularly shaped particles contained in the aluminum-containing particles increases, the particle size distribution of the aluminum-containing particles becomes wider (D 90 / D 10 In other words, the present inventors have found that the particle size distribution of the aluminum-containing particles can be used as an evaluation index for the number of irregular-shaped particles contained in the aluminum-containing particles.

[0015] The present inventors have conducted extensive research to obtain aluminum-containing particles having a narrower particle size distribution. As a result, they have found that aluminum-containing particles having a narrower particle size distribution can be obtained by adjusting the oxygen concentration in the atmosphere in a step of obtaining aluminum-containing particles by an atomization method. That is, according to the method for producing aluminum-containing particles of the present embodiment, aluminum-containing particles having a narrower particle size distribution can be obtained. Also, according to the method for producing aluminum-containing particles of the present embodiment, the number of irregular-shaped particles contained in the aluminum-containing particles can be reduced.

[0016] In this specification, the irregularly shaped particles refer to aluminum-containing particles having a small circularity (for example, elliptical particles). The irregularly shaped particles may or may not have satellite particles, which will be described later. Irregularly shaped particles may be defined, for example, as aluminum-containing particles having a circularity of 0.6 or less. The circularity of an aluminum-containing particle means a value calculated by image analysis of an image obtained by a scanning electron microscope, and specifically, means a value calculated by analyzing the area and circumference of an aluminum-containing particle and using the formula: circularity = 4π area / (circumference ^2).

[0017] Hereinafter, each step in the method for producing aluminum-containing particles according to the present embodiment will be described.

[0018] <Molten metal preparation process> The method for producing aluminum-containing particles of the present embodiment preferably includes, prior to step (A), a step of preparing a molten metal that is a raw material for the aluminum-containing particles.

[0019] The method for preparing the molten metal is not particularly limited, but examples thereof include a method in which an aluminum alloy ingot is placed in a primary furnace and heated; a method in which an aluminum ingot and each element are placed in a primary furnace and heated so as to obtain the desired composition of aluminum-containing particles; and the like. The molten metal in this embodiment may contain flux. As the flux, for example, a mixed salt of a chlorine compound (NaCl·KCl) and a fluorine compound (NaF·Na2SiF6) can be used. The content of the flux in the molten metal in this embodiment may be, for example, 0.1 parts by mass or more and 1 part by mass or less, or 0.2 parts by mass or more and 0.3 parts by mass or less, when the aluminum alloy ingot (or the total of the aluminum ingot and each element) is 100 parts by mass.

[0020] The heating temperature when preparing the molten metal is not particularly limited, and may be appropriately adjusted taking into consideration the melting point of aluminum or the melting point of the aluminum-based alloy (or the melting point of the aluminum-based alloy derived from the composition of the target aluminum-containing particles). When the aluminum-containing particles of the present embodiment contain AlSi10Mg, the heating temperature is preferably 700° C. or more and 900° C. or less, more preferably 800° C. or more and 850° C. or less.

[0021] The molten metal obtained in the primary furnace may be transferred to a secondary furnace and held in the secondary furnace. The temperature at which the molten metal is maintained is not particularly limited, and may be appropriately adjusted taking into consideration the melting point of aluminum or the melting point of the aluminum-based alloy (or the melting point of the aluminum-based alloy derived from the composition of the target aluminum-containing particles). When the aluminum-containing particles of the present embodiment contain AlSi10Mg, the holding temperature is preferably 600°C or more and 900°C or less, more preferably 650°C or more and 800°C or less.

[0022] The primary furnace and the secondary furnace are not particularly limited as long as they are melting furnaces that can be used to produce molten metal, and for example, an electric furnace, a high-frequency induction furnace, etc. can be used.

[0023] <Process (A)> The method for producing aluminum-containing particles of the present embodiment includes a step (A) of obtaining aluminum-containing particles (a) by an atomization method.

[0024] The oxygen concentration in the atmosphere in step (A) is 4500 ppm or less. The oxygen concentration in the atmosphere in step (A) is preferably 3500 ppm or less, more preferably 2500 ppm or less, even more preferably 1500 ppm or less, even more preferably 1000 ppm or less, even more preferably 500 ppm or less, even more preferably 300 ppm or less, even more preferably 150 ppm or less, even more preferably 100 ppm or less, even more preferably 80 ppm or less, even more preferably 50 ppm or less. When the oxygen concentration is equal to or less than the upper limit, aluminum-containing particles having a narrower particle size distribution can be obtained. Also, when the oxygen concentration is equal to or less than the upper limit, the content of aluminum-containing particles (B) having satellite particles can be further reduced.

[0025] The atomization method is not particularly limited, and may be any method selected from the group consisting of disk atomization, gas atomization, water atomization, and plasma atomization, and is preferably disk atomization.

[0026] In the step (A), when the aluminum-containing particles (a) are obtained by disk atomization, a preferred embodiment is as follows. The diameter of the rotating disk is not particularly limited, but is preferably φ30 mm or more and φ40 mm or less. From the viewpoint of further reducing the proportion of coarse particles in the aluminum-containing particles (a), the rotation speed of the rotating disk is preferably 50,000 rpm or more and 110,000 rpm or less, more preferably 60,000 rpm or more and 100,000 rpm or less, even more preferably 70,000 rpm or more and 90,000 rpm or less, and even more preferably 75,000 rpm or more and 85,000 rpm or less.

[0027] In step (A), the rate of tapping of the molten metal is preferably 20 kg / h or more and 80 kg / h or less, more preferably 25 kg / h or more and 70 kg / h or less, and even more preferably 25 kg / h or more and 60 kg / h or less. When the amount of the molten metal tapped is equal to or greater than the lower limit, the production amount per unit time can be improved. When the amount of the molten metal tapped is equal to or less than the upper limit, the proportion of coarse particles in the aluminum-containing particles (a) can be reduced, thereby improving the classification yield. The amount of molten metal discharged can be adjusted, for example, by adjusting the size of the nozzle diameter of the secondary furnace.

[0028] The type of atomizing device used in step (A) is not particularly limited, but for example, a spherical powder manufacturing device (manufactured by Minerva Machinery Co., Ltd.) can be used.

[0029] <Process (B)> The method for producing aluminum-containing particles of the present embodiment includes a step (B) of classifying the aluminum-containing particles (a) to obtain aluminum-containing particles (b). Step (B) is a step carried out after step (A). An optional step may be provided between step (A) and step (B).

[0030] Step (B) is preferably a step of removing coarse particles from the aluminum-containing particles (a) to obtain the aluminum-containing particles (b), and more specifically, preferably a step of sieving the aluminum-containing particles (a) using a sieve and recovering the aluminum-containing particles (a) that have passed through the sieve to obtain the aluminum-containing particles (b). Here, the opening diameter of the sieve is, for example, 200 μm or more and 300 μm or less, and preferably 250 μm.

[0031] The classifier used in step (B) is not particularly limited, but for example, a vibrating sieve equipped with an ultrasonic oscillator (manufactured by Koei Sangyo Co., Ltd.) can be used.

[0032] <Stirring process> The method for producing aluminum-containing particles of the present embodiment preferably includes a step of stirring the aluminum-containing particles (b) between step (B) and step (C) described below.

[0033] The method of stirring the aluminum-containing particles (b) is not particularly limited, but for example, a method of stirring the aluminum-containing particles (b) using a mixer can be mentioned. As the mixer, for example, an Infinite Mixer (manufactured by Tokuju Kogyosho Co., Ltd.) can be used.

[0034] <Process (C)> The method for producing aluminum-containing particles of the present embodiment preferably further includes a step (C) of classifying the aluminum-containing particles (b). Step (C) is a step carried out after step (B). An optional step may be provided between step (B) and step (C).

[0035] In the step (C), the method for classifying the aluminum-containing particles (b) is not particularly limited. Step (C) may be, for example, a step of removing coarse particles and fine powder from the aluminum-containing particles (b), a step of removing only coarse particles from the aluminum-containing particles (b), or a step of removing only fine powder from the aluminum-containing particles (b).

[0036] Step (C) is a step of classifying the aluminum-containing particles (b), for example, by sieving the aluminum-containing particles (b) using an upper screen and a lower screen as sieves and recovering the aluminum-containing particles (b) that passed through the upper screen but not the lower screen. In addition, step (C) may be a step of classifying the aluminum-containing particles (b) by, for example, sieving the aluminum-containing particles (b) using only an upper screen as a sieve and recovering the aluminum-containing particles (b) that have passed through the upper screen, or a step of classifying the aluminum-containing particles (b) by sieving the aluminum-containing particles (b) using only a lower screen as a sieve and recovering the aluminum-containing particles (b) that have not passed through the lower screen.

[0037] The opening diameter of the upper screen is, for example, 40 μm to 180 μm, and preferably 50 μm to 170 μm, while the opening diameter of the lower screen is, for example, 5 μm to 30 μm, and preferably 10 μm to 20 μm. By appropriately adjusting the opening diameter of the upper screen and the opening diameter of the lower screen, the particle diameter of the aluminum-containing particles can be adjusted to a desired value.

[0038] The classifier used in step (C) is not particularly limited, but for example, a Hi-Bolter (blow-through type classifier, manufactured by Toyo Hightec Co., Ltd.) can be used.

[0039] <Other processes> The method for producing aluminum-containing particles of the present embodiment may include other steps as appropriate in addition to the steps described above.

[0040] [Aluminum-containing particles] A preferred embodiment of the aluminum-containing particles obtained by the method for producing aluminum-containing particles of this embodiment will be described.

[0041] The aluminum-containing particles obtained by the method for producing aluminum-containing particles of the present embodiment may be aluminum-containing particles obtained after step (C), may be aluminum-containing particles (a), or may be aluminum-containing particles (b) obtained before step (C).

[0042] D of the aluminum-containing particles of this embodiment 50 The particle size is preferably 30.0 μm or more and 60.0 μm or less, more preferably 32.0 μm or more and 58.0 μm or less, even more preferably 34.0 μm or more and 55.0 μm or less, and even more preferably 36.0 μm or more and 53.0 μm or less.

[0043] D of the aluminum-containing particles of this embodiment 10 The particle size is preferably 20.0 μm or more and 40.0 μm or less, more preferably 22.0 μm or more and 38.0 μm or less, and further preferably 25.0 μm or more and 36.0 μm or less.

[0044] D of the aluminum-containing particles of this embodiment 90 The particle size is preferably 50.0 μm or more and 100.0 μm or less, more preferably 52.0 μm or more and 95.0 μm or less, even more preferably 55.0 μm or more and 90.0 μm or less, and even more preferably 56.0 μm or more and 85.0 μm or less.

[0045] D of the aluminum-containing particles of this embodiment 90 Particle diameter is D 10 The value divided by the particle diameter is preferably 1.5 or more and 4.0 or less, more preferably 1.6 or more and 3.5 or less, even more preferably 1.7 or more and 3.0 or less, and even more preferably 1.8 or more and 2.7 or less.

[0046] Here, D of aluminum-containing particles 10 Particle size, D 50 Particle size and D 90 The particle size refers to a value calculated by <Particle Size Measurement> described below.

[0047] <Particle size measurement> 3.0 g of aluminum-containing particles were mixed with 40 mL of water and 10 mL of a 1.3% surfactant, and dispersed in an ultrasonic bath for 300 seconds to obtain a measurement sample. The volume-based particle size distribution of the aluminum-containing particles was measured using a laser diffraction / scattering particle size measurement device, and the D 10 Particle size, D 50 Particle size and D 90 The particle size values ​​are obtained respectively. Here, as the surfactant with a concentration of 1.3%, for example, an aqueous solution obtained by diluting the original solution of Fresh Green Apple with Fruit Acid (manufactured by Rocket Soap Co., Ltd.) by 11 times can be used. In addition, the surfactant is, for example, linear alkylbenzenesulfonate sodium.

[0048] The sphericity of the aluminum-containing particles of this embodiment is preferably 0.8 or more, more preferably 0.85 or more, and even more preferably 0.9 or more. The sphericity of an aluminum-containing particle means a value calculated by image analysis of an image obtained by a scanning electron microscope, and specifically means a value calculated by measuring the short axis length and long axis length of an aluminum-containing particle, determining the sphericity of a single aluminum-containing particle using the formula sphericity = short axis length / long axis length, and then arithmetically averaging the sphericities of 100 or more aluminum-containing particles.

[0049] The aluminum-containing particles of the present embodiment preferably include aluminum-containing particles (A) having no satellite particles and aluminum-containing particles (B) having satellite particles.

[0050] 1 is a schematic diagram showing an example of a cross section of an aluminum-containing particle (B) having satellite particles. Particle (B) 100 refers to a particle in which satellite particles 20 are attached to a main particle 10. Here, in this specification, the main particle 10 refers to the particle having the largest particle diameter contained in particle (B), and particles other than the main particle 10 contained in particle (B) are referred to as satellite particles 20. It should be noted that particle (A) can also be said to be a particle consisting only of main particles 10. The particles (B) may contain a plurality of satellite particles.

[0051] The content of particles (A) is preferably 10% or more, more preferably 20% or more, even more preferably 30% or more, even more preferably 40% or more, even more preferably 45% or more, even more preferably 50% or more, even more preferably 55% or more, even more preferably 60% or more, even more preferably 65% ​​or more. The upper limit of the content of particles (A) is not particularly limited, but may be, for example, 100% or less, 95% or less, 90% or less, 80% or less, or 75% or less. The content of particles (A) means the value calculated by <Method 2>.

[0052] <Method 2> The aluminum-containing particles are observed using a scanning electron microscope, and the ratio of the number of particles (A) to the total number of aluminum-containing particles observed is defined as the content of particles (A).

[0053] The content of particles (B) is preferably 90% or less, more preferably 80% or less, even more preferably 70% or less, even more preferably 60% or less, even more preferably 55% or less, even more preferably 50% or less, even more preferably 45% or less, even more preferably 40% or less, even more preferably 35% or less. The lower limit of the content of particles (B) is not particularly limited, but may be, for example, 0% or more, 5% or more, 10% or more, 20% or more, or 25% or more. The content of particles (B) means the value calculated by <Method 1>.

[0054] <Method 1> The aluminum-containing particles are observed using a scanning electron microscope, and the ratio of the number of particles (B) to the total number of aluminum-containing particles observed is defined as the content of particles (B).

[0055] Hereinafter, the observation methods for aluminum-containing particles using a scanning electron microscope in <Method 1> and <Method 2> will be specifically described.

[0056] First, a method for preparing a sample for observation using a scanning electron microscope will be described. The observation sample is a sample in which 100 or more aluminum-containing particles are dispersed so as not to overlap one another. The method for preparing the observation sample is not particularly limited, but for example, the observation sample can be prepared by placing a double-sided tape on the surface of a pedestal, dropping aluminum-containing particles onto the exposed surface of the double-sided tape, and removing excess aluminum-containing particles with air or the like.

[0057] Next, the observation sample is imaged by a scanning electron microscope to obtain an SEM image. At this time, for one level, for example, 20 or more SEM images are obtained while shifting the imaging position. The magnification is not particularly limited as long as the satellite particles can be confirmed, but is, for example, 500 times. As the scanning electron microscope, for example, SU8200 (manufactured by Hitachi High-Technologies Corporation) can be used.

[0058] The method for determining particles (A) and particles (B) will be specifically described below.

[0059] 2 to 4 are SEM images of aluminum-containing particles for explaining how to distinguish between particle (A) and particle (B).

[0060] First, 100 or more aluminum-containing particles are observed using the obtained SEM image, and it is visually determined whether or not the aluminum-containing particles contain satellite particles. Aluminum-containing particles that do not contain satellite particles and can be clearly determined to consist of a single particle are designated as aluminum-containing particles without satellite particles (A). Aluminum-containing particles that can be clearly determined to contain satellite particles are designated as aluminum-containing particles with satellite particles (B).

[0061] Here, the aluminum-containing particles in Figs. 2 and 3 are particles in which a coating 30 is attached to at least a part of a main particle 10 (hereinafter, also referred to as "coated particles"). Even in the case of such coated particles, aluminum-containing particles that can be clearly determined to have satellite particles 20, as in Fig. 2, are judged to be aluminum-containing particles (B) that have satellite particles. On the other hand, particles in which satellite particles 20 cannot be confirmed, as in Fig. 3, are judged to be aluminum-containing particles (A) that do not have satellite particles.

[0062] In the SEM images, only a portion of an aluminum-containing particle is captured, and the entire particle cannot be grasped. Since it is not possible to clearly determine whether or not there are satellite particles, the aluminum-containing particle is not observed.

[0063] Further, the observation sample is prepared by dispersing the aluminum-containing particles so that they do not overlap with one another, but there are cases where it is unavoidable that some of the aluminum-containing particles overlap with one another. Fig. 4 is an SEM image in which parts of the outermost surfaces of aluminum-containing particles overlap each other. As in Fig. 4, when the entirety of each aluminum-containing particle can be grasped and the presence or absence of satellite particles can be determined, each aluminum-containing particle may be observed. In Fig. 4, it is determined that there is one aluminum-containing particle (A) that does not have satellite particles and one aluminum-containing particle (B) that has satellite particles. In addition, even when most of the aluminum-containing particles overlap each other and each aluminum-containing particle cannot be grasped in its entirety, the particle is still observed, and the group of particles is determined to be aluminum-containing particles (B) having satellite particles.

[0064] The aluminum-containing particles of the present embodiment are not particularly limited as long as they contain aluminum (Al) element, but preferably contain at least one type selected from the group consisting of pure aluminum particles and aluminum-based alloy particles, and more preferably contain aluminum-based alloy particles. Here, the pure aluminum particles refer to particles made of aluminum with a purity of 99.00% or more (so-called 1000 series aluminum), and the aluminum alloy particles refer to an aluminum alloy containing Al as a main component.

[0065] The aluminum-based alloy particles of the present embodiment preferably contain at least one element selected from the group consisting of Cu, Mn, Si, Mg, Zn, and Ni, and more preferably contain at least one element selected from the group consisting of Si and Mg. When the aluminum-based alloy particles of this embodiment contain Si, the Si content in the aluminum-based alloy particles is preferably 7.00 mass% or more and 15.00 mass% or less, more preferably 8.00 mass% or more and 14.00 mass% or less, and even more preferably 9.00 mass% or more and 11.00 mass% or less, when the aluminum-based alloy particles are 100.00 mass%. When the aluminum-based alloy particles of this embodiment contain Mg, the Mg content in the aluminum-based alloy particles is preferably 0.10 mass% or more and 0.60 mass% or less, and more preferably 0.20 mass% or more and 0.45 mass% or less, when the aluminum-based alloy particles are taken as 100.00 mass%. The contents of the other elements are not particularly limited and may be set to appropriate amounts. The content of each element can be determined by, for example, elemental analysis using solid-state emission spectrometry.

[0066] The aluminum alloy particles of the present embodiment preferably contain at least one selected from the group consisting of an Al-Si based alloy, an Al-Cu based alloy, an Al-Mn based alloy, an Al-Mg based alloy, an Al-Si-Mg based alloy, an Al-Si-Cu based alloy, an Al-Zn-Mg based alloy, an Al-Si-Mg-Cu based alloy, an Al-Cu-Ni-Mg based alloy, and an Al-Zn-Mg-Cu based alloy, and more preferably contain at least one selected from the group consisting of an Al-Si based alloy and an Al-Si-Mg based alloy.

[0067] The composition of the aluminum-based alloy particles of this embodiment is not particularly limited, and may be any composition selected from the group consisting of, for example, aluminum alloys for rolling, aluminum alloys for casting, and aluminum alloys for die casting, but is preferably an aluminum alloy composition for casting. The composition of the aluminum alloy for casting is, for example, the composition specified in JIS H2211:2010.

[0068] The aluminum-based alloy particles of the present embodiment preferably contain at least one selected from the group consisting of AlSi10Mg and AlSi12, and more preferably contain AlSi10Mg. Here, AlSi10Mg and AlSi12 refer to alloys that satisfy the composition specified in JIS H2211:2010.

[0069] [Uses of aluminum-containing particles] The use of the aluminum-containing particles of the present embodiment is not particularly limited. The aluminum-containing particles of the present embodiment are aluminum-containing particles that can be used for at least one selected from the group consisting of, for example, raw material powders for 3D printer objects and soldering paste powders, and are preferably aluminum-containing particles that can be used for aluminum-containing particles.

[0070] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can also be adopted. Furthermore, the present invention is not limited to the above-described embodiment, and modifications and improvements within the scope of the present invention that can achieve the object of the present invention are included in the present invention. EXAMPLES

[0071] The present embodiment will be described in detail below based on examples and comparative examples. Note that the present embodiment is not limited to the descriptions of these examples.

[0072] [Example 1] <Molten metal preparation process> An aluminum alloy ingot (AlSi10Mg) was placed in a primary furnace (electric furnace, manufactured by Ducor Corporation), and a flux (product name: Tsubasa Flux Smokeless, manufactured by Tokyo Molex Crucible Co., Ltd.) was added in an amount of 0.2 parts by mass per 100 parts by mass of the aluminum alloy ingot. The mixture was then heated to 830°C to prepare a molten metal. The obtained molten metal was transferred from the primary furnace to a secondary furnace (high-frequency induction furnace manufactured by High Frequency Systems Co., Ltd.) The molten metal was maintained at a temperature of 770°C in the secondary furnace.

[0073] <Atomization process (Process (A))> Using the molten metal in the secondary furnace as a raw material, aluminum-containing particles (a) were obtained by disk atomization under the following conditions. Disk atomizer: Spherical powder manufacturing device (Minerva Machinery Co., Ltd.) Rotating disc diameter: φ35mm Revolutions per minute: 82,000 rpm Molten metal output: 44kg / h Secondary furnace nozzle diameter: φ2mm Oxygen concentration: 30ppm or less

[0074] Here, the oxygen concentration refers to the oxygen concentration in the spray chamber, and refers to the value measured by an oxygen concentration meter (product name: zirconia oxygen concentration meter RF-30, manufactured by Toray Engineering Co., Ltd.) The oxygen concentration was adjusted to the target oxygen concentration by appropriately injecting compressed air or nitrogen gas into the spray chamber.

[0075] <Classification process (process (B))> The aluminum-containing particles (a) were classified using a vibrating sieve machine (manufactured by Koei Sangyo Co., Ltd., product name: vibrating sieve with ultrasonic oscillator UB70UR-3S, sieve mesh opening diameter: 250 μm) to obtain aluminum-containing particles (b). Here, the aluminum-containing particles (a) that passed through the sieve mesh were collected and used as aluminum-containing particles (b). The obtained aluminum-containing particles (b) were used as the aluminum-containing particles of Example 1.

[0076] [Examples 2 to 4 and 6 to 8, Comparative Example 1] The aluminum-containing particles of Examples 2 to 4 and 6 to 8 and Comparative Example 1 were obtained in the same manner as in Example 1 except that the conditions shown in Table 1 were used.

[0077] [Example 5] First, aluminum-containing particles (b) were obtained in the same manner as in Example 1, except that the conditions shown in Table 1 were used.

[0078] <Stirring process> The aluminum-containing particles (b) were stirred at 29 rpm for 5 minutes using a mixer (manufactured by Tokuju Industrial Co., Ltd., product name: Infinite Mixer MM-220). The aluminum-containing particles (b) after stirring were used as the aluminum-containing particles of Example 5.

[0079] In Table 1, "Flux" indicates whether or not flux was added in the molten metal preparation process.

[0080] [measurement] The following measurements were carried out on the aluminum-containing particles of Examples 1 to 8 and Comparative Example 1. The measurement results are shown in Table 2. In Table 2, "-" means that no measurement was performed.

[0081] <Elemental analysis> Using a solid-state optical emission analyzer (manufactured by Thermo Fischer SCIENTIFIC, product name: ARL-3460), elemental analysis by solid-state optical emission spectrometry was performed on the aluminum-containing particles of Examples 1 to 8 and Comparative Example 1. As a result of the elemental analysis, the composition of the aluminum-containing particles of Examples 1 to 8 and Comparative Example 1 was an alloy represented by AlSi10Mg.

[0082] <Particle size> The measurement sample was prepared by mixing 3.0 g of aluminum-containing particles with 40 mL of water and 10 mL of a 1.3% surfactant, dispersing the mixture in an ultrasonic bath for 300 seconds. The 1.3% surfactant was prepared by diluting the original solution of Fresh Green Apple with Fruit Acid (manufactured by Rocket Soap Co., Ltd., surfactant (sodium linear alkylbenzene sulfonate) 14%) 11 times. Specifically, the 1.3% surfactant was prepared by diluting 50 mL of the original solution of Fresh Green Apple with Fruit Acid with 500 mL of water. The volumetric particle size distribution of aluminum-containing particles was measured using a laser diffraction / scattering particle size analyzer (Microtrac, product name: MT-3300EX II) for the measurement sample, and D 10 Particle size, D 50 Particle size and D 90The particle size values ​​were obtained. 10 Particle size and D 90 From the particle size value, D 90 Particle diameter is D 10 Divided by particle diameter (D 90 / D 10 ) was calculated.

[0083] <Content of particles (A) and particles (B)> First, an observation sample was prepared in which 100 or more aluminum-containing particles were fixed to the surface of a pedestal. Here, the aluminum-containing particles were dispersed in the observation sample so that they did not overlap with each other. Specifically, the observation sample was prepared by placing double-sided tape on the surface of the pedestal, dropping the aluminum-containing particles onto the exposed surface of the double-sided tape, and removing the excess aluminum-containing particles with air. Using a scanning electron microscope (Hitachi High-Tech Corporation, product name: SU8200), SEM images were obtained at 500x magnification of the sample for observation. For each level, more than 20 SEM images were obtained by shifting the imaging position.

[0084] Using the obtained SEM image, 100 or more aluminum-containing particles were observed to determine the number of aluminum-containing particles (A) having no satellite particles and the number of aluminum-containing particles (B) having satellite particles. Then, the ratio of the number of particles (A) and the number of particles (B) to the total number of particles observed was calculated to determine the content of particles (A) and the content of particles (B), respectively.

[0085] The particles (A) and the particles (B) were judged based on the method for judging the particles (A) and the particles (B) described in the embodiment of the invention.

[0086] 5 is a SEM image of the aluminum-containing particles of Example 5. FIG. 6 is a representation of FIG. The symbols A and B in FIG. 6 correspond to particle (A) and particle (B), respectively.

[0087] <Sphericity> The sphericity of the aluminum-containing particles was determined by image analysis using ImageJ for the SEM images obtained in the above <Content of particles (A) and particles (B)>. Specifically, the short axis length and long axis length of the aluminum-containing particles were measured, and the sphericity of one aluminum-containing particle was determined using the formula sphericity = short axis length / long axis length. The sphericity of 100 or more aluminum-containing particles was calculated as the arithmetic average, and this value was regarded as the sphericity of the aluminum-containing particle.

[0088] <Evaluation of irregularly shaped particles> Using the SEM images obtained in the above <Contents of Particles (A) and Particles (B)>, 100 or more aluminum-containing particles were observed, and the presence or absence of irregularly shaped particles was evaluated. The circularity of the aluminum-containing particles was determined by image analysis using ImageJ for the SEM images obtained in the above <Content of Particle (A) and Particle (B)>. Specifically, the area and circumference of the aluminum-containing particles were analyzed by image analysis, and the circularity of one aluminum-containing particle was calculated using the formula: circularity = 4π area / (circumference^2). Next, aluminum-containing particles with a circularity of 0.6 or less were determined to be irregularly shaped particles, and the ratio of the number of irregularly shaped particles to the total number of aluminum-containing particles observed was calculated to obtain the content of irregularly shaped particles. A: The content of irregularly shaped particles is less than 6%. B: The content of irregularly shaped particles is 6% or more and less than 8%. C: The content of irregularly shaped particles is 8% or more.

[0089] [Table 1]

[0090] [Table 2]

[0091] From Table 2, the aluminum-containing particles of the examples have a lower D than the aluminum-containing particles of the comparative examples. 90 / D 10That is, according to the method for producing aluminum-containing particles of the present embodiment, the particle size distribution of the obtained aluminum-containing particles can be made narrower. In addition, the aluminum-containing particles of the examples all had good evaluation results for irregularly shaped particles. That is, it can be understood that the method for producing aluminum-containing particles of the present embodiment can reduce the number of irregularly shaped particles contained in the aluminum-containing particles. [Explanation of symbols]

[0092] 10 main particles 20 Satellite Particles 30 Covering 100 particles (B) A particle (A) B particle (B)

Claims

1. A step (A) of obtaining aluminum-containing particles (a) by an atomization method; and a step (B) of classifying the aluminum-containing particles (a) to obtain aluminum-containing particles (b), The method for producing aluminum-containing particles, wherein the oxygen concentration in the atmosphere in the step (A) is 4500 ppm or less, The method for producing aluminum-containing particles, wherein a value obtained by dividing a D 90 particle diameter by a D 10 particle diameter of the aluminum-containing particles, as calculated by the following <Particle diameter measurement>, is 1.5 or more and 4.0 or less. <Particle size measurement> 3.0 g of aluminum-containing particles are mixed with 40 mL of water and 10 mL of a 1.3% surfactant, and dispersed in an ultrasonic bath for 300 seconds to obtain a measurement sample. A laser diffraction / scattering type particle size measurement device is used to measure the volume-based particle size distribution of the aluminum-containing particles to obtain the D10 particle size, D50 particle size, and D90 particle size values, respectively.

2. The method for producing aluminum-containing particles according to claim 1 , wherein the atomization method is a disk atomization method.

3. 3. The method for producing aluminum-containing particles according to claim 2, wherein in the step (A), the rotation speed of the rotating disk is 50,000 rpm or more and 110,000 rpm or less.

4. The method for producing aluminum-containing particles according to any one of claims 1 to 3, further comprising a step (C) of classifying the aluminum-containing particles (b) after the step (B).

5. The aluminum-containing particles have a diameter D calculated by the following <Particle diameter measurement>. ５０ The method for producing aluminum-containing particles according to any one of claims 1 to 3, wherein the particle diameter is 30.0 µm or more and 60.0 µm or less. <Particle size measurement> 3.0 g of aluminum-containing particles were mixed with 40 mL of water and 10 mL of a 1.3% surfactant, and the mixture was dispersed in an ultrasonic bath for 300 seconds to obtain a measurement sample. The volume-based particle size distribution of the aluminum-containing particles was measured using a laser diffraction / scattering particle size measuring device. １０ Particle size, D ５０ Particle size and D ９０ The particle size values ​​are obtained respectively.

6. The aluminum-containing particles have a diameter D calculated by the following <Particle diameter measurement>. １０ The method for producing aluminum-containing particles according to any one of claims 1 to 3, wherein the particle diameter is 20.0 µm or more and 40.0 µm or less. <Particle size measurement> 3.0 g of aluminum-containing particles were mixed with 40 mL of water and 10 mL of a 1.3% surfactant, and the mixture was dispersed in an ultrasonic bath for 300 seconds to obtain a measurement sample. The volume-based particle size distribution of the aluminum-containing particles was measured using a laser diffraction / scattering particle size measuring device. １０ Particle size, D ５０ Particle size and D ９０ The particle size values ​​are obtained respectively.

7. The aluminum-containing particles have a diameter D calculated by the following <Particle diameter measurement>. ９０ The method for producing aluminum-containing particles according to any one of claims 1 to 3, wherein the particle diameter is 50.0 µm or more and 100.0 µm or less. <Particle size measurement> 3.0 g of aluminum-containing particles were mixed with 40 mL of water and 10 mL of a 1.3% surfactant, and the mixture was dispersed in an ultrasonic bath for 300 seconds to obtain a measurement sample. The volume-based particle size distribution of the aluminum-containing particles was measured using a laser diffraction / scattering particle size measuring device. １０ Particle size, D ５０ Particle size and D ９０ The particle size values ​​are obtained respectively.

8. The aluminum-containing particles include aluminum-containing particles (A) having no satellite particles and aluminum-containing particles (B) having satellite particles, The method for producing aluminum-containing particles according to any one of claims 1 to 3, wherein the content of the aluminum-containing particles (B) having satellite particles, calculated by the following <Method 1>, is 90% or less. <Method 1> The aluminum-containing particles are observed using a scanning electron microscope, and the ratio of the number of aluminum-containing particles (B) having satellite particles to the total number of aluminum-containing particles observed is defined as the content of aluminum-containing particles (B) having satellite particles.

9. The method for producing aluminum-containing particles according to any one of claims 1 to 3, wherein the aluminum-containing particles have a sphericity of 0.8 or more.

10. The method for producing aluminum-containing particles according to any one of claims 1 to 3, wherein the aluminum-containing particles include at least one selected from the group consisting of pure aluminum particles and aluminum-based alloy particles.

11. The method for producing aluminum-containing particles according to claim 10, wherein the aluminum-based alloy particles contain at least one element selected from the group consisting of Cu, Mn, Si, Mg, Zn, and Ni.

12. The method for producing aluminum-containing particles according to claim 10, wherein the aluminum-based alloy particles contain at least one selected from the group consisting of an Al-Si based alloy, an Al-Cu based alloy, an Al-Mn based alloy, an Al-Mg based alloy, an Al-Si-Mg based alloy, an Al-Si-Cu based alloy, an Al-Zn-Mg based alloy, an Al-Si-Mg-Cu based alloy, an Al-Cu-Ni-Mg based alloy, and an Al-Zn-Mg-Cu based alloy.

13. The method for producing aluminum-containing particles according to claim 10, wherein the aluminum-based alloy particles contain at least one selected from the group consisting of AlSi10Mg and AlSi12.

14. The method for producing aluminum-containing particles according to any one of claims 1 to 3, wherein the aluminum-containing particles can be used as a raw material powder for a 3D printer model.

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