JPH0310009A - Method and apparatus for manufacturing metal fine powder - Google Patents

Abstract

PURPOSE:To easily manufacture high purity metal fine powder with good efficiency by duplicately focusing ultrasonic wave in pressurized inert gas atmosphere on molten metal stream to produce fine drips and cooling and solidifying them. CONSTITUTION:Into a vessel 13 of the inert gas atmosphere of Ar, etc., having the pressure higher than the outside air pressure, the molten metal 12 in a holding vessel 10 at the upper part thereof, is allowed to flow down as column or thin film state metal stream from a bottom nozzle 14. At the same time, the ultrasonic wave is generated with an ultrasonic wave generator 1 using Ar gas as medium and focused on the molten metal stream, and after pulverizing the molten metal stream into the fine drip state, the ultrasonic wave is reflected with a reflecting device 26 and again focusing on the molten metal stream. As the other way, by focusing the ultrasonic waves from the ultrasonic wave generators 1, 1' on two positions at upper and lower parts of the molten metal stream, the molten metal stream is made to the fine drip state with good yield of the raw material, and cooled and solidified with cooling gas from a cooling gas supplying device to make the metal fine powder 25. Further, as the atmospheric pressure in the vessel 13 is higher than the outside air pressure, the metal fine powder is not oxidized by inversion of the outside air.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing fine metal powder and an apparatus therefor.

[Prior Art] Conventionally, as a method and apparatus for manufacturing fine metal powder using ultrasonic vibration, for example, Japanese Patent Application Laid-Open No. 58-110604
No. 61-295306 is disclosed. These conventional techniques will be explained with reference to the drawings. Figure 5 (A).

In both cases (B), molten metal 52 is made to flow down from above into a conical resonator 51, and the molten metal 52 atomized by the ultrasonic vibration of the resonator 51 becomes microparticles 53, and the cooling gas is supplied. It is cooled by the cooling gas 55 ejected from the tube 54 to produce fine metal powder. In FIG. 6, a resonator 61 is immersed in molten metal 62, and the ultrasonic vibrations generated from this generate minute metal particles 63 from the surface of the molten metal 62, which are placed inside a chamber 64 maintained in an inert atmosphere. The metal powder is cooled by the cooling gas introduced from the cooling gas inlet 65, and a fine metal powder is produced.

[Problems to be Solved by the Invention] However, the above-mentioned conventional technology has the following problems.

(2) Since the temperature of the molten metal flowing down or immersed into the resonator is generally high, alloying elements or impurities contained in the resonator mix into the molten metal, making it impossible to obtain fine metal powder of high purity.

■If a heat-resistant ceramic material is used to withstand the temperature of molten metal, the vibration characteristics will be poor and the desired vibration will not be obtained.

(2) Fluctuations in the thickness of the molten metal formed on the resonator result in variations in the directly produced fine metal powder, but it is difficult to control the thickness.

The present invention has been made in view of the above points, and an object of the present invention is to provide a method for manufacturing fine metal powder and an apparatus therefor, which can efficiently manufacture fine metal powder into containers. .

[Means for Solving the Problems] The manufacturing method of the present invention includes a step of melting a metal material to create a metal melt, a step of causing the metal melt to flow down to create a metal melt flow, and a step of making the metal melt flow. The method is characterized by comprising a step of atomizing the metal melt into minute droplets by focusing ultrasonic waves on the surface of the liquid stream, and a step of cooling and solidifying the minute droplets. Here, the process of atomizing the metal melt into minute droplets by focusing ultrasonic waves on the surface of the metal melt flow is carried out while maintaining the atmospheric gas in contact with the metal melt flow in a predetermined pressurized state. is preferred. Further, it is preferable to include a step of atomizing the metal melt into minute droplets by focusing ultrasonic waves on the surface of the metal melt flow in a residual flowing state after atomizing the minute droplets.

Further, the manufacturing method of the present invention includes a step of melting a metal material to create a metal melt, a step of causing the metal melt to flow down to create a metal melt flow, and an ultrasonic wave applied to the surface of the metal melt flow. to atomize the metal melt into minute droplets; to reflect the ultrasonic waves to create reflected ultrasonic waves; and to focus the reflected ultrasonic waves on the metal melt stream to atomize the metal melt into minute droplets. It is characterized by comprising the steps of atomizing the melt into micro droplets, and cooling and solidifying the micro droplets by spraying a cooling gas onto the micro droplets from a direction different from the direction in which the ultrasonic waves travel.

In these methods, it is preferable that the metal stream has a cylindrical or thin film shape.

The manufacturing apparatus of the present invention includes a heating means for melting a metal material to produce a metal melt, and a flow means disposed adjacent to the heating means for causing the metal melt to flow down, and a holder for holding the metal melt. an ultrasonic wave generating means for generating a predetermined ultrasonic wave, and an ultrasonic wave generating means for generating a predetermined ultrasonic wave, which is provided between the ultrasonic wave generating means and the holding body to focus the ultrasonic wave on the surface of the metal melt flowing down and generate the metal melt. It is characterized by comprising a focusing means for atomizing the liquid into minute droplets, and a cooling means for cooling the minute droplets. here,
It is preferable to include a pressurizing means for maintaining the pressure of the atmospheric gas in contact with the flowing molten metal at a predetermined pressurized state.

In addition, the ultrasonic wave is provided between the ultrasonic generating means and the holding body to atomize the metal melt into minute droplets by focusing the ultrasonic waves on the surface of the residual flowing metal melt flow after atomizing the minute droplets. It is preferable to include a focusing means for causing the

Further, the manufacturing apparatus of the present invention includes a heating means for melting a metal material to produce a metal melt, and a flowing means disposed adjacent to the heating means for causing the metal melt to flow down, and holding the metal melt. a holder that focuses ultrasonic waves on the surface of the flowing metal melt to atomize the metal melt into minute droplets; an ultrasonic reflecting means that reflects and focuses sound waves on the surface of the flowing metal melt to atomize the metal melt into minute droplets; It is characterized by comprising a cooling means for cooling by spraying cooling gas from the direction.

Any heating means may be used as long as it can easily melt the metal material into a metal melt. Examples of such devices include heater radiant tubes, lasers, and the like.

The ultrasonic wave generating means may be any device that can generate ultrasonic waves having energy that can atomize the metal melt into minute droplets by focusing. An example of such a device is an ultrasonic generator that uses a normal high-frequency power source.

Further, in this case, the ultrasonic focusing means is preferably one that focuses the ultrasonic waves on a single point or a negative line, in which case the ultrasonic waves are concentrated on the surface of the metal melt to increase the energy. Furthermore, during the operation of pulverizing metal, a combination of - point focusing type and line focusing type focusing means may be used, or a plurality of these may be attached. However, in this case, the metal melt should be installed so that it converges on the surface of the flow. This is because it is difficult to focus ultrasonic waves on particles that have been made into fine particles to further make them fine particles, and also because the focusing point of the ultrasonic waves is not constant, causing the inconvenience that the efficiency of making fine particles deteriorates. be. It goes without saying that a plurality of second and subsequent focusing means may be attached to the metal melt flow in a residual flowing state after being atomized by the first focusing means.

Furthermore, when focusing the ultrasonic waves, it is preferable that the direction in which the ultrasonic waves travel with respect to the metal melt flow is within a deflection angle of ±45'' with respect to the n-line orthogonal to the metal excitation liquid flow. It is particularly preferable that the ultrasonic waves travel in a direction perpendicular to the metal melt flow.

The velocity of the metal melt flow is 0.4 to 2.4 m/sec.
It is preferable that it is e. This means that a stable I7 metal melt flow cannot be obtained below 0.4 m/s, and 2.4 m/s
This is because if the value exceeds ee, the ultrasonic waves cannot be reliably focused on the surface of the metal melt flow. The most preferred flow rate is 0.7 m/see. Further, it is preferable that the metal melt flow has a cylindrical shape or a thin film shape, for example.

The pressurizing means may be of any type as long as it can maintain a pressure state that improves the transmission efficiency of ultrasonic waves. Examples of such devices include those that directly adjust the atmospheric gas pressure of the flowing metal melt, and those that substantially create a pressurized state by increasing the temperature of the atmospheric gas. may be provided directly within the device, or a badge-type chamber or the like may be provided separately from the device and connected to the device.

The ultrasonic reflecting means used is one that can efficiently reflect ultrasonic waves and refocus the reflected ultrasonic waves synchronously on the surface of the metal melt without attenuating them.

When ultrasound is focused using ultrasound reflecting means, −
It is also possible to reflect the ultrasonic waves focused on the metal melt and refocus them on the metal melt surface, or instead of directly focusing the ultrasonic waves on the metal melt surface, the ultrasonic waves are reflected by an ultrasonic reflecting means and then reflected. It may also be focused on the surface of the metal melt. In this case, it goes without saying that the ultrasonic wave may be used in combination with one that focuses the ultrasonic wave directly on the surface of the metal melt. Note that it is preferable that the direction of travel of the ultrasonic wave and the direction of travel of the cooling gas have a predetermined angle. Preferably, the direction in which the ultrasonic waves travel and the direction in which the cooling gas travels are perpendicular. This is to prevent the atomized minute droplets from hitting the ultrasonic reflecting means and to efficiently produce fine metal powder. Further, the distance between the ultrasonic wave reflecting means and the metal melt is preferably an integral multiple of the wavelength of the ultrasonic wave to be reflected.

[Function] According to the method and apparatus for producing fine metal powder according to the present invention, ultrasonic waves are generated, the phases of the ultrasonic waves are aligned, and the ultrasonic waves are focused on the surface of the metal melt. The metal melt is atomized into minute droplets by the energy of this ultrasonic wave.

Therefore, since the ultrasonic resonator is not in contact with the metal melt, it is possible to produce high-purity fine particles without introducing impurities into the atomized metal melt, and to extend the life of the resonator. . In addition, since the metal melt is flowing down,
Compared to the badge type, it is possible to continuously supply raw metal into the holding container while maintaining a balance with the flow rate.
It is possible to prevent the vortex phenomenon of the metal melt that occurs when the remaining amount of the metal melt becomes small, and it is possible to stably and efficiently produce metal fine powder. Furthermore, fine metal powder can be produced from a flowing metal melt that is always clean.

According to the present invention, by atomizing the metal melt while keeping the atmospheric gas in a pressurized state, the density of the medium gas is increased, and as a result, the transmission efficiency of ultrasonic waves is sufficiently increased. be able to. Therefore, fine metal powder can be efficiently produced.

Further, according to the present invention, by using the ultrasonic reflecting means, in addition to the ultrasonic waves focused directly on the metal melt, the ultrasonic waves focused by the reflecting means are added, and the ultrasonic waves are focused on the surface of the metal melt. The amount of ultrasonic waves generated increases, and as a result, the amount of fine metal powder produced can be increased.

Further, according to the present invention, by providing a plurality of ultrasonic focusing means, the ultrasonic waves are focused on the surface of the residual metal melt flow after being atomized into minute droplets, and the ultrasonic waves are focused on the surface of the residual metal melt flow after being atomized into minute droplets. By increasing the diameter of the metal melt flowing down to increase the amount of metal melt flowing down, it is possible to increase the amount of metal fine powder produced.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. Note that the explanation of the manufacturing method of the present invention includes the explanation of the operation of the apparatus of the embodiment.

Embodiment 1 FIG. 1 is an explanatory diagram showing the configuration of an embodiment of the present invention.

In the figure, 10 is a holding container that holds molten metal.

A heater 11 for melting the metal material is installed outside the holding container 10, and a metal melt 12 is held inside the holding container 10. This holding container 10 is
It is provided above the chamber 13 in communication with the chamber 13 which is maintained in an inert gas atmosphere. Further, a nozzle 14 for causing the metal melt 12 to flow down into the chamber 13 is provided at the bottom of the holding container 10. Chamber 13
An ultrasonic generator 1 is provided on the side. Ultrasound/
The wave generator 1 includes a high frequency power source 15 provided outside the chamber 13, a high frequency vibrator 16, and the chamber 1.
A resonator 18 provided in the chamber 13, a radial direction converter 19 provided surrounding the resonator 18 for focusing the ultrasonic waves, and a transducer 16 inserted through the chamber 13 and the radial direction converter 19. and an amplitude expander 17 connected between the resonator 18 and the resonator 18.

Here, the material of the resonator 18 is preferably a titanium alloy or an aluminum alloy. Furthermore, since the radiation direction converter 19 has opposite phases on the vibrator side and the anti-vibrator side of the resonator 18, it is possible to superimpose these antiphase radiated sound waves in the same phase on the surface of the metal melt. is set up.

Moreover, one radiation direction converter has a reflecting surface set in a parabolic shape in order to efficiently cause sound waves to reach the surface of the metal melt.

Further, at the side end of the chamber 13, the chamber 1
A device 20 is provided which communicates with the inside of the cooling gas and supplies cooling gas. This device 20 includes a pressure detector 21, a pressure ':A regulating valve 22 based on the pressure detector 21, and a compressor 23 that causes cooling gas to flow into the chamber 13. moreover,
A recovery device 24 for recovering the manufactured fine metal powder is connected to the other end of the chamber 13.

Next, the operation of the apparatus for manufacturing fine metal powder constructed as described above will be explained.

First, the metal melt 12 held in the holding container 10 is maintained at a temperature equal to or higher than the melting point of the metal material by the heater 11. Thus, the metal melt flows down from the nozzle 14 into the chamber 13.

The inside of the chamber 13 is maintained in an inert atmosphere using an inert gas such as Ar gas. This prevents oxidation or other chemical reactions of the metal melt 12 flowing down. The metal melt 12 is in a flowing state and always maintains a high degree of cleanliness.

Next, the ultrasonic vibrator 16 is vibrated by the high frequency power source 15, and the resonator 18 connected to the vibrator 16 is vibrated. By appropriately selecting the frequency of this ultrasonic wave, the particle size of the fine metal powder can be changed. Resonator 18
Ultrasonic waves are emitted using the atmospheric gas as a medium due to the vibrations. This radiated ultrasonic wave is transmitted to the metal melt 12 in a flowing state.
The beams are focused by the radiation direction converter 19 so as to be in phase with each other on the surface of the beam.

In this way, when the focused ultrasonic waves act on the surface of the metal melt 12, capillary waves are created on the surface of the metal melt 12, which overcomes the surface tension and separates the micro droplets 25 from the surface of the metal melt 12. scatter. Scattered minute droplets 25
is cooled and solidified by the cooling gas, and is carried to the collector 24 and recovered by the flow of the cooling gas. In this way, clean metal particles free of impurities can be obtained.

Next, an experimental example conducted to confirm the effects of the present invention will be described.

Using the apparatus shown in Figure 1, the argon gas atmosphere was maintained at an absolute pressure of 1 kg/c-, and the resonator was vibrated at a frequency of 20 KHz, causing vibrations with a single amplitude of approximately 12 microns. However, an ultrasonic wave with a sound pressure level of 172 dB was obtained near the surface of the metal melt in a flowing state. A titanium alloy was used as the resonator, and an aluminum alloy was used as the molten metal. By applying ultrasonic waves with these characteristics to the surface of the flowing aluminum alloy liquid,
Micronized. Note that the flow rate of the aluminum alloy liquid was 0.7 m/sec.

The obtained aluminum alloy powder has a particle size of 40 to . 100
They were spherical particles with an average particle size of 70 microns. In addition, there was no oxidation on the particle surface or any contamination of impurity elements, and the metal powder was of extremely high purity. Note that the amount of particles produced was approximately 700 grams/hour.

Embodiment 2 FIG. 2 is an explanatory diagram showing the structure of an embodiment of the present invention. Note that the explanation of parts that overlap with Embodiment 1 will be omitted.

13 in the figure is a chamber. A cooling gas supply device 20 that communicates with the inside of the chamber 13 and supplies cooling gas is provided at a side end of the chamber 13 . This device 20 includes a pressure detector 21 and a pressurizing means 2 based thereon (a pressure regulating valve 22), and has a compressor 23 that flows cooling gas into a chamber 13. Furthermore, a recovery device 24 for recovering the manufactured fine metal powder is connected to the other end of the chamber 13.

Next, the operation of the apparatus for manufacturing fine metal powder constructed as described above will be explained.

First, the metal melt 12 held in the holding container 10 is maintained at a temperature equal to or higher than the melting point of the metal material by the heater 11. Thus, the metal melt flows down from the nozzle 14 into the chamber 13.

The metal melt 12 is in a flowing state and always maintains a high degree of cleanliness. Further, the pressure inside the chamber 13 is maintained at a predetermined pressurized state at least at atmospheric pressure by adjusting the inert gas pressure by the pressurizing means 2.

Next, the ultrasonic vibrator 16 is vibrated by the high frequency power source 15, and the resonator 18 connected to the vibrator 16 is vibrated. Ultrasonic waves are emitted by the vibration of the resonator 18 using the atmospheric gas as a medium. In this case, the a1 atmosphere gas is in a pressurized state, so it has a high density and transmits ultrasonic waves efficiently.

The radiated ultrasonic waves are focused by the radial direction converter 19 so as to overlap with each other in phase on the surface of the metal melt 12 in a flowing state.

In this way, when the focused ultrasonic waves act on the surface of the metal melt 12, capillary waves are created on the surface of the metal melt 12, which overcomes the surface tension and separates the micro droplets 25 from the surface of the metal melt 12. scatter. Scattered minute droplets 25
is cooled and solidified by the cooling gas, and is carried to the collector 24 and recovered by the flow of the cooling gas. In this way, clean metal particles free of impurities can be obtained.

Next, an experimental example conducted to confirm the effects of the present invention will be described.

Using the apparatus shown in Figure 2, the argon gas atmosphere was maintained at an absolute pressure of 3 kg/cd, and the resonator was vibrated at a frequency of 20 KHz to produce vibrations of approximately 12 microns with a single amplitude. , an ultrasonic wave with a sound pressure level of 182 dB was obtained near the surface of the metal melt in a flowing state. A titanium alloy was used as the resonator, and an aluminum alloy was used as the molten metal. By applying ultrasonic waves with these characteristics to the surface of the flowing aluminum alloy liquid,
Micronized. Note that the flow rate of the aluminum alloy liquid was 0.7 m/sec.

The obtained aluminum alloy powder was spherical particles with a particle size of 40 to 100 microns and an average particle size of 70 microns.

In addition, there was no oxidation on the particle surface or any contamination of impurity elements, and the metal powder was of extremely high purity. Note that the amount of particles produced was approximately 1100 grams/hour.

Embodiment 3 FIG. 3 is an explanatory diagram showing the configuration of an embodiment of the present invention. Note that explanations of parts that overlap with those of Example 1 will be omitted.

13 in the figure is a chamber. An ultrasonic generator 1 is provided on the side of the chamber 13. Further, in the chamber 13, an ultrasonic reflecting means 26 is provided so as to face the ultrasonic generator 1 and position the metal melt 12 flowing down between the ultrasonic generator 1 and the ultrasonic generator 1. . The distance (L) between the ultrasonic wave reflecting means 26 and the metal melt 12 flowing down is set to an integral multiple of the wavelength of the ultrasonic wave to be focused on the metal melt 12. Furthermore, the ultrasonic generating means 1 and the ultrasonic reflecting means 26 are installed so that the direction of movement of the ultrasonic waves and the direction of movement of the cooling gas are substantially orthogonal.

Next, the operation of the apparatus for manufacturing fine metal powder constructed as described above will be explained.

First, the metal melt 12 held in the holding container 10 is maintained at a temperature equal to or higher than the melting point of the metal material by the heater 11. Thus, the metal melt flows down from the nozzle 14 into the chamber 13.

Next, the ultrasonic vibrator 16 is vibrated by the high frequency power source 15, and the resonator 18 connected to the vibrator 16 is vibrated. Ultrasonic waves are emitted by the vibration of the resonator 18 using the atmospheric gas as a medium. The radiated ultrasound is transmitted through the radial direction converter 1
9, they are focused on the surface of the metal melt 12 in a flowing state so that they are in the same phase and overlap. Micro droplets 25 are generated from the metal melt 12 by the focusing of the radiated ultrasonic waves.

Furthermore, the emitted ultrasound reaches the ultrasound reflection means 26 provided opposite to the ultrasound generator 1, and is reflected there.
They are refocused on the surface of the metal melt 12 in a flowing state so that they overlap in the same phase.

That is, when the emitted ultrasonic waves and the reflected ultrasonic waves converge and act on the surface of the metal melt 12, capillary waves are created on the surface of the metal melt 12, which overcomes the surface tension and causes the micro liquid to flow from the surface of the metal melt 12. Scatter drops 25. The scattered minute droplets 25 are cooled and solidified by the cooling gas, and are carried to the collector 24 and collected by the flow of the cooling gas. In this way, clean metal particles free of impurities can be obtained.

Next, an experimental example conducted to confirm the effects of the present invention will be described.

Using the apparatus shown in Figure 3, the argon gas atmosphere was maintained at an absolute pressure of 1 kg/c4, and the resonator was vibrated at a frequency of 20 KHz to produce vibrations of approximately 12 microns with a single amplitude. , the sound pressure level near the surface of the metal melt in a flowing state is approximately 1 when no ultrasonic reflecting means is provided.
．． It was 175 dB, which is equivalent to 5 times. A titanium alloy was used as the resonator, and an aluminum alloy was used as the molten metal. Ultrasonic waves with such characteristics were applied to the surface of the aluminum alloy liquid in a flowing state, and the aluminum alloy was pulverized. In addition, the flow rate of the aluminum alloy liquid is 0.7
m/sea. Further, the distance (L) between the ultrasonic reflecting means and the metal melt flowing down was set to 3.6 cm.

The obtained aluminum alloy powder was spherical particles with a particle size of 40 to 100 microns and an average particle size of 70 microns.

In addition, there was no oxidation on the particle surface or any contamination of impurity elements, and the metal powder was of extremely high purity. The amount of particles produced was approximately 830 grams/hour.

Embodiment 4 FIG. 4 is an explanatory diagram showing the configuration of an embodiment of the present invention. Note that explanations of parts that overlap with those of Example 1 will be omitted.

In the figure, 10 is a holding container. A nozzle 1 is provided at the bottom of the holding container 10 to flow the metal melt 12 into the chamber 13.
4 is provided. Here, the diameter of the metal melt flow is
It is necessary to set it to 10++++i or more. This is because if the diameter of the metal melt flow is less than 10III, the residual metal melt cannot flow. An ultrasonic generator 1 is provided on the side of the chamber 13.

Further, an ultrasonic generator 1' is provided below the ultrasonic generator 1 at a constant distance. The ultrasonic generator 1' is
Like the ultrasonic generator 1, it is composed of a high frequency power source 15', a high frequency vibrator 16', an amplitude expander 17', a resonator 18', and a radial direction converter 19'. This ultrasonic generator 1' is set so that the direction of propagation of the ultrasonic waves is perpendicular to the residual metal melt flow after the ultrasonic waves generated from the ultrasonic generator 1 are focused and atomized. There is.

Here, the material of the resonators 18, 18' is preferably titanium alloy or aluminum alloy.

Furthermore, the radial direction converters 19 and 19' each include a resonator 18
．． Since the vibrator side and the anti-vibrator side of 18' have opposite phases, they are installed so that the radiated sound waves of opposite phases can be superimposed in the same phase on the surface of the metal melt. Further, the radiation direction converters 19 and 19' have their reflecting surfaces set in a parabolic shape in order to efficiently cause the sound waves to reach the surface of the metal melt.

Next, the operation of the apparatus for manufacturing fine metal powder constructed as described above will be explained.

First, the metal melt 12 held in the holding container 10 is maintained at a temperature equal to or higher than the melting point of the metal material by the heater 11. Since the metal melt 12 flows down from the nozzle 14 into the chamber 13, it is in a flowing state and always maintains a high degree of cleanliness.

Next, the ultrasonic vibrator 16 is vibrated by the high frequency power source 15, and the resonator 18 connected to the vibrator 16 is vibrated. Ultrasonic waves are emitted by the vibration of the resonator 18 using the atmospheric gas as a medium. The radiated ultrasonic waves are focused by the radial direction converter 19 so as to overlap with each other in phase on the surface of the metal melt 12 in a flowing state.

When the focused ultrasonic waves act on the surface of the metal melt 12, pillar waves are formed on the surface of the metal melt 12, which overcomes the surface tension and causes minute droplets 25 to flow from the surface of the metal melt 12.
scatter.

The metal melt 12 that has not been atomized into minute droplets 25 flows further down as a residual metal melt flow. The radiated ultrasonic waves emitted by the ultrasonic generator 1' are focused on the surface of this metal melt flow in the same manner as described above.

Thereby, minute droplets 25' are scattered from the surface of the metal melt 12 by second-stage atomization.

The scattered minute liquid a25' is cooled and solidified by the cooling gas, and is carried to the collector 24 and collected by the flow of the cooling gas. In this way, clean metal particles free of impurities can be obtained.

Next, an experimental example conducted to confirm the effects of the present invention will be described.

Using the apparatus shown in Figure 4, the argon gas atmosphere was maintained at an absolute pressure of 1 kg/cd, and the resonator was vibrated at a frequency of 20 KHz to produce vibrations with a single amplitude of approximately 12 microns. , an ultrasonic wave with a sound pressure level of 172 dB was obtained near the surface of the metal melt in a flowing state. A titanium alloy was used as the resonator, and an aluminum alloy was used as the molten metal. Ultrasonic waves having such characteristics were applied to the surface of the flowing aluminum alloy liquid to perform the first stage of atomization. Note that the flow rate of the aluminum alloy liquid was 0.7 m/see. Next, the frequency 2 is applied to the metal melt flow in the residual flow state in the same manner as described above.
Ultrasonic waves having the characteristics of 0 KHz, single amplitude of 12 microns, and sound pressure level of 172 dB near the surface of the metal melt were focused to perform atomization in the second stage of atomization.

The aluminum alloy powder obtained after the first and second atomization was spherical particles with a particle size of 40 to 100 microns and an average particle size of 70 microns. In addition, there was no oxidation on the particle surface or any contamination of impurity elements, and the metal powder was of extremely high purity. Note that the amount of particles produced was approximately 1300 grams/hour.

[Effects of the Invention] As explained above, according to the method and apparatus for producing fine metal powder according to the present invention, fine metal powder of high purity can be produced efficiently and easily.

[Brief explanation of the drawing]

1 to 4 are explanatory diagrams showing the configuration of a manufacturing apparatus for fine metal powder according to an embodiment of the present invention, and FIGS. 5(A) and 5(B)
FIG. 6 is an explanatory diagram showing a conventional metal fine particle manufacturing technique in which molten metal is made to flow down into a resonator, and FIG. 6 is an explanatory diagram showing a conventional metal fine particle manufacturing technique in which a resonator is immersed in molten metal. 10... Holding container, 11... Heater 12...
Metal melt, 13...chamber 14...nozzle,
15゜15'... High frequency power supply, 16.16'... Vibrator, 17.17'... Amplitude expander, 18.18'
...Resonator, 19.19'...Radiation direction converter, 2
0... Cooling gas supply device, 21... Pressure detector, 2
2...Pressure regulating valve, 23...Compressor, 24...Collector, 25° 25'...Minute droplet, 26...Ultrasonic reflecting means. Figure 1: Figure 2

Claims (9)

[Claims] (1) A step of melting a metal material to create a metal melt, a step of causing the metal melt to flow down to create a metal melt flow, and a step of focusing ultrasonic waves on the surface of the metal melt flow to 1. A method for producing fine metal powder, comprising the steps of atomizing a melt into fine droplets, and cooling and solidifying the fine droplets. (2) The process of atomizing the metal melt into minute droplets by focusing ultrasonic waves on the surface of the metal melt flow is performed while maintaining the atmospheric gas in contact with the metal melt flow at a predetermined pressurized state. Claim 1
The method for producing the metal fine powder described above. Claim 1, further comprising the step of: (3) atomizing the metal melt into minute droplets by focusing ultrasonic waves on the surface of the metal melt flow in a residual flowing state after atomizing the minute droplets. A method for producing fine metal powder. (4) A step of melting a metal material to create a metal melt, a step of causing the metal melt to flow down to create a metal melt flow, and a step of focusing ultrasonic waves on the surface of the metal melt flow to A step of atomizing the melt into minute droplets, a step of reflecting the ultrasonic waves to create reflected ultrasonic waves, and focusing the reflected ultrasonic waves on the metal melt flow to turn the metal melt into minute droplets. a process of atomizing the
A method for producing fine metal powder, comprising a step of cooling and solidifying the fine droplets by spraying a cooling gas onto the fine droplets from a direction different from the direction in which the ultrasonic waves travel. (5) The method for producing fine metal powder according to any one of claims 1 to 4, wherein the metal melt flow has a cylindrical shape or a thin film shape. (6) heating means for melting a metal material to create a metal melt;
a holder that is disposed adjacent to the heating means and includes a flowing means for causing the metal melt to flow down; a holder that holds the metal melt; an ultrasonic generation means that generates a predetermined ultrasonic wave; a focusing means provided between the holders, which focuses the ultrasonic waves on the surface of the flowing metal melt to atomize the metal melt into minute droplets; and a cooling means, which cools the minute droplets. An apparatus for producing fine metal powder, comprising: (7) The apparatus for producing fine metal powder according to claim 6, further comprising pressurizing means for maintaining the pressure of the atmospheric gas in contact with the flowing molten metal at a predetermined pressurized state. (8) The ultrasonic wave is provided between the ultrasonic generating means and the holding body to atomize the metal melt into minute droplets by focusing the ultrasonic waves on the surface of the residual flowing metal melt flow after atomizing the minute droplets. 7. The apparatus for producing fine metal powder according to claim 6, further comprising a convergence means for making the fine metal powder. (9) heating means for melting a metal material to create a metal melt;
A holder for holding the metal melt, which is provided adjacent to the heating means and allows the metal melt to flow down; and a holder for holding the metal melt; a focusing means for atomizing the melt into minute droplets; and a focusing means installed opposite to the focusing means to reflect the ultrasonic waves and focus them on the surface of the metal melt flowing down. A metal fine powder characterized by comprising an ultrasonic reflecting means for atomizing into minute droplets, and a cooling means for cooling the minute droplets by spraying cooling gas from a direction different from the direction in which the ultrasonic waves travel. manufacturing equipment.