JP5299445B2 - Metal powder manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal powder production apparatus capable of efficiently producing fine metal powder with a uniform particle size, and to provide metal powder by the metal powder production apparatus which has an increased quality. <P>SOLUTION: The metal powder production apparatus (atomizer) 1 makes use of an atomizing method to pulverize molten metal Q into powder so as to obtain many metal powder R. The metal powder production apparatus 1 includes a supply part (tundish) 2 for supplying the molten metal Q, a nozzle 3 provided below the supply part 2, and a tubular member 10 provided between the supply part 2 and the nozzle 3. The tubular member 10 is constructed to ensure that the molten metal Q ejected from an ejection port 23 passes through a bore of the tubular member and then makes contact with a fluid jet S1. Further, the tubular member 10 has a top end air-tightly connected to the supply part 2 and a bottom end lying around the midway of a first flow path 31 through which the molten metal Q passes. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

The present invention relates to a method for producing metal powder.

Conventionally, in order to manufacture a metal powder, a metal powder manufacturing apparatus (atomizer) that powders molten metal by an atomizing method has been used. As this metal powder production apparatus, for example, a “molten metal spray pulverization apparatus” described in Patent Document 1 is known.
This molten metal spraying and pulverizing apparatus has a discharge port for discharging molten metal (molten metal) downward, a channel through which the molten metal discharged from the discharge port passes, and a slit having an opening in the channel. And. Water is jetted from the slit of this nozzle.

The apparatus of Patent Document 1 collides a molten metal passing through a flow channel with water jetted from a slit, thereby scattering the molten metal into a large number of fine droplets and cooling the large number of droplets. Solidified and thereby configured to produce metal powder.
The molten metal discharged from the discharge port naturally falls and passes through the flow path and comes into contact with water. However, since the path through which the molten metal passes changes depending on many factors such as the flow rate of water and the shape of the nozzle, the position where the molten metal comes into contact with water changes. For this reason, there exists a problem that dispersion | distribution arises in the particle size and particle size distribution of the metal powder which the state of molten metal scattering and cooling solidification changes.

  Furthermore, since air flows from the surroundings into the decompressed flow path, an air flow is formed in the vicinity of the flow path. However, when the molten metal comes into contact with this air, the quality of the metal powder may be deteriorated due to solidification due to a decrease in the temperature of the molten metal or alteration / deterioration due to oxidation. In particular, such a problem is remarkable when the molten metal contains a highly active metal such as Ti or Al.

Japanese Patent Publication No. 3-55522

An object of the present invention is to provide a metal powder production method capable of efficiently producing a fine metal particle having a uniform particle diameter.

The above object is achieved by the present invention described below.
In the metal powder production method of the present invention, the molten metal is stored in the supply unit,
The molten metal of the supply unit, with discharges to the lumen of the tubular member which is installed below the supply part, the said molten metal by dividing means provided at the lower end of the tubular member Divided in the circumferential direction of the lower end,
In the flow path that is disposed below the supply portion and into which the lower end portion of the cylindrical member is inserted, an air flow is formed downward along the outer peripheral surface of the cylindrical member, and the cylindrical member By reducing the pressure near the lower end , the molten metal in the cylindrical member is discharged,
The molten metal discharged from the cylindrical member is primarily divided into a large number of droplets,
A liquid fluid is ejected from an orifice that opens at the lower end of the flow path, and the liquid droplets are scattered by colliding with the liquid droplets obtained by the primary division, so that a larger number of finer liquids The droplets are divided into two, and the plurality of droplets obtained by the second division are cooled and solidified.
Thereby, it is possible to efficiently produce a fine metal powder having a uniform particle diameter.

In the metal powder manufacturing method of the present invention, the flow path has a shape in which the inner diameter gradually decreases from the upper end toward the middle of the flow path and gradually increases from the middle toward the lower end, and the liquid fluid is supplied from the orifice. It is preferable that the pressure in the vicinity of the lower end of the cylindrical member is reduced by spraying.

In the metal powder manufacturing method of the present invention , the cylindrical member preferably has a cylindrical shape .

In the metal powder manufacturing method of the present invention, it is preferable that the dividing means has a structure in which the thickness of the lower end portion of the cylindrical member gradually decreases as it goes downward .
In the metal powder manufacturing method of the present invention, it is preferable that the dividing unit divides the molten metal almost evenly.
In the metal powder manufacturing method of the present invention, it is preferable that the cylindrical member is arranged so that a lower end portion thereof is positioned near a position where the molten metal is primarily split.

It is a mimetic diagram (longitudinal sectional view) showing a 1st embodiment of a metal powder manufacturing device used for a metal powder manufacturing method of the present invention. FIG. 2 is an enlarged detailed view (schematic diagram) of a region [A] surrounded by a one-dot chain line in FIG. 1. FIG. 2 is an enlarged detailed view (schematic diagram) of a region [B] surrounded by a two-dot chain line in FIG. 1. It is a fragmentary sectional view showing other examples of composition of a cylindrical member typically. It is a fragmentary sectional view showing other examples of composition of a cylindrical member typically. It is an enlarged detailed view (schematic diagram) showing a part of the second embodiment of the metal powder production apparatus used in the metal powder production method of the present invention. It is an enlarged detail figure (schematic diagram) which shows a part of 3rd Embodiment of the metal powder manufacturing apparatus used for the metal powder manufacturing method of this invention.

Hereinafter, with the metal powder production method of the present invention will be described in detail with reference to the accompanying drawings.
<First Embodiment>
First, 1st Embodiment of the metal powder manufacturing apparatus used for the metal powder manufacturing method of this invention is described.
FIG. 1 is a schematic diagram (longitudinal sectional view) showing a first embodiment of a metal powder production apparatus used in the metal powder production method of the present invention, and FIG. 2 is a region surrounded by an alternate long and short dash line in FIG. ] FIG. 3 is an enlarged detail view (schematic diagram) of a region [B] surrounded by a two-dot chain line in FIG. In the following description, the upper side in FIGS. 1 to 3 is referred to as “upper” and the lower side is referred to as “lower”.
A metal powder production apparatus (atomizer) 1 shown in FIG. 1 is used to obtain a large number of metal powders R by pulverizing a molten metal Q by an atomization method. The metal powder manufacturing apparatus 1 includes a supply unit (tundish) 2 for supplying a molten metal Q, a nozzle 3 provided below the supply unit 2, and a cylindrical shape provided between the supply unit 2 and the nozzle 3. A member 10 is provided.

Hereinafter, the configuration of each unit will be described.
As shown in FIG. 1, the supply unit 2 has a bottomed cylindrical part. A molten metal Q obtained by melting a raw material of the metal powder to be manufactured is temporarily stored in the internal space (lumen portion) 22 of the supply unit 2.
A discharge port 23 is provided at the center of the bottom 21 of the supply unit 2. From the discharge port 23, the molten metal Q in the internal space 22 is discharged downward by natural fall.

A nozzle 3 is provided below the supply unit 2.
The nozzle 3 has a first flow path (flow path) 31 through which the molten metal Q supplied (discharged) from the supply section 2 passes and a water supply source for supplying fluid (water in this embodiment). A second flow path 32 through which water S from (not shown) passes is formed.
The first channel 31 has a circular cross-sectional shape, and is formed in the center of the nozzle 3 along the vertical direction.

  The first flow path 31 has an inner diameter gradually decreasing portion 33 in which the inner diameter of the nozzle 3 gradually decreases downward from the upper end surface 41, that is, has a convergent shape. Thereby, the air (gas) G above the nozzle 3 is drawn into the inner diameter gradually decreasing portion 33 by the flow of water S ejected from the orifice 34 described later. The drawn air G has a maximum flow velocity in the vicinity of the portion 331 where the inner diameter of the inner diameter gradually decreasing portion 33 is minimum (the portion where the orifice 34 opens). As a result of such a flow of air G, the pressure (atmospheric pressure) of the first flow path 31 gradually decreases from above toward this portion 331.

When the molten metal Q passes through the first flow path 31 in such a reduced pressure state, the surrounding pressure is reduced, and if the degree of the surrounding reduced pressure becomes higher than the force to be concentrated, the molten metal Q is scattered (primary Split). Thereby, the molten metal Q becomes a large number of droplets Q1.
In the first flow path 31, the position where primary splitting occurs in the molten metal due to the decrease in the surrounding pressure is referred to as “primary splitting position”.

Here, the vicinity of the portion 331 where the inner diameter of the inner diameter gradually decreasing portion 33 is the smallest has been described as the region where the pressure is most reduced. However, the position of this region depends on the shape, angle, etc. of the inner diameter gradually decreasing portion 33 and the orifice 34. Therefore, the position is not limited to the position of the present embodiment.
In the present embodiment, the inner diameter of the inner diameter gradually decreasing portion 33 continuously decreases downward. Thereby, the inner peripheral surface of the inner diameter gradually decreasing portion 33 becomes smooth. Then, the air G drawn into the inner diameter gradually decreasing portion 33 is accelerated without delay along the inner peripheral surface, and the pressure in the first flow path 31 becomes lower. In particular, in the vicinity of the portion 331 where the inner diameter of the inner diameter gradually decreasing portion 33 is the smallest in the first flow path 31, the flow velocity of the air G is the fastest, and thus the pressure in this vicinity is further reduced. Thereby, the molten metal Q can be scattered more finely and the more fine droplet Q1 can be obtained.

As shown in FIG. 2, the second flow path 32 includes an orifice 34 that opens at the lower end (near the portion 331) of the first flow path 31, a storage section 35 that temporarily stores water S, and storage. It is constituted by an introduction path 36 for introducing water S from the portion 35 to the orifice 34.
The storage unit 35 is connected to the water supply source and is a part to which water S is supplied from the water supply source.
The reservoir 35 communicates with the orifice 34 through the introduction path 36.

The introduction path 36 is a part whose longitudinal cross-sectional shape forms a wedge shape. Thereby, the flow rate of the water S flowing in from the storage part 35 can be gradually increased, and the water S in a state where the flow rate is increased can be stably ejected from the orifice 34.
The orifice 34 is a part that injects (spouts) the water S that has passed through the reservoir 35 and the introduction path 36 in this order into the first flow path 31.

The orifice 34 opens in a slit shape over the entire circumference of the inner peripheral surface of the first flow path 31. The orifice 34 opens in a direction inclined with respect to the central axis O of the first flow path 31.
By the orifice 34 formed in this way, the water S is ejected as a liquid jet S1 having a substantially conical shape with the top portion S2 positioned below (see FIG. 1). The liquid droplet S1 comes into contact with the liquid jet S1 and scatters (secondary division), and further refined.

At this time, the droplet Q1 is cooled and solidified. Thereby, the metal powder R is manufactured.
The metal powder R thus produced is collected in a container (not shown) provided at the lower part of the metal powder production apparatus 1.
As shown in FIGS. 1 and 2, the nozzle 3 in which the first flow path 31 and the second flow path 32 are formed includes the first member 4 having a disk shape (ring shape), and the first member 4. And a disk-shaped (ring-shaped) second member 5 provided concentrically. The second member 5 is provided below the first member 4 via a gap 37.

The first member 4 and the second member 5 arranged in this way define the orifice 34, the introduction path 36, and the storage part 35, respectively. That is, the second flow path 32 is configured by the gap 37 formed between the first member 4 and the second member 5.
Although it does not specifically limit as a constituent material of the 1st member 4 and the 2nd member 5, For example, various metal materials can be used, It is preferable to use especially stainless steel.

As shown in FIG. 1, a cover 7 made of a cylindrical body is fixed to the lower end surface 51 of the second member 5. The cover 7 is provided concentrically with the first flow path 31.
The cover 7 can prevent the metal powder R falling down from being scattered, so that the metal powder R can be reliably stored in the container.
Further, it is preferable that the cover 7 is airtightly connected to the lower end surface 51 of the second member 5. Thereby, it is possible to prevent outside air from flowing into the cover 7. As a result, when the droplet Q1 undergoes secondary splitting, it is possible to reliably prevent outside air from coming into contact with the droplet Q1 and the droplet Q1 to be oxidized and denatured.

Furthermore, the inside of the cover 7 is decompressed by the action of the liquid jet S1. Thereby, the pressure in the 1st flow path 31 connected with the inside of the cover 7 will also fall further. As a result, in the primary division, the molten metal Q is more finely divided, so that finer droplets Q1, and thus a finer metal powder R can be obtained.
From this viewpoint, the inner diameter of the cover 7 is preferably about 1 to 4 times the ring diameter of the orifice 34 (diameter of the annular orifice 34), and more preferably about 1.5 to 3 times. Thereby, the pressure in the cover 7 can be sufficiently lowered while the droplet Q1 is sufficiently cooled.
If the inner diameter of the cover 7 falls below the lower limit value, there is a possibility that the droplet formed by dividing the droplet Q1 cannot be sufficiently cooled in the secondary division. For this reason, there exists a possibility that the shape of the obtained metal powder R may become a different shape.

On the other hand, if the inner diameter of the cover 7 exceeds the upper limit value, the pressure in the cover 7 may not be sufficiently reduced. For this reason, there is a possibility that the inside of the first flow path 31 communicating with the inside of the cover 7 cannot be further depressurized.
Here, in the conventional metal powder manufacturing apparatus (atomizer), the molten metal discharged from the discharge port of the supply unit passes through the flow path while naturally falling in the air and comes into contact with the fluid jet. It was.

  As described above, an air flow is formed in the flow path by the action of the fluid jet. For this reason, the path | route in which the molten metal which falls freely falls by this air flow is disturbed. Thereby, when the molten metal passes through the primary splitting position, the passing position is not constant. As a result, there is a problem in that the degree of scattering (primary breakup) due to decompression (droplet size, etc.) varies, and the dispersion of the particle size distribution of the finally obtained metal powder becomes large.

  In addition, the molten metal that falls freely comes into contact with the air that has flowed into the flow path, causing the solidification due to a decrease in the temperature of the molten metal and the deterioration / degradation due to oxidation. There was also a problem of sticking to. For this reason, in particular, when a highly active metal such as Ti or Al is included, it is necessary to provide the discharge port 23 having a somewhat large size. In this case, the particle size of the obtained metal powder also becomes large according to the size of the discharge port 23, and it was difficult to obtain a fine and high-quality metal powder.

  Therefore, in the present invention, the cylindrical member 10 is provided between the supply unit 2 and the first flow path 31 of the nozzle 3. The tubular member 10 is for guiding the molten metal Q discharged from the discharge port 23 through the inside (lumen portion) and into the first flow path 31. Since such a cylindrical member 10 shields the flow of the air G, the molten metal Q can be guided to an appropriate position, and primary splitting at the primary splitting position can surely occur. Thereby, scattering by decompression is made reliably and the metal powder R with fine and uniform particle diameter is obtained.

Further, since the flow of the air G is shielded in this way, it is possible to suppress deterioration or deterioration due to solidification or oxidation due to a temperature drop of the molten metal Q. Therefore, according to the metal powder manufacturing apparatus 1, the metal powder R containing a highly active metal can also be manufactured easily.
Furthermore, even when the size of the discharge port 23 is reduced and the discharge amount of the molten metal Q is reduced due to such an effect, the molten metal Q can be prevented from being deteriorated due to solidification or oxidation due to a temperature drop of the molten metal. Can be reliably discharged. Further, when the discharge amount of the molten metal Q is reduced, fine droplets Q1 corresponding to the discharge amount can be formed, so that a finer metal powder R can be finally obtained.

The metal powder R produced by such a metal powder production apparatus 1 preferably has an average particle size of about 1 to 20 μm, and more preferably about 1 to 10 μm. For the production of such fine metal powder R, the metal powder production method of the present invention can be suitably used.

  In this embodiment, the cylindrical member 10 is long as shown in FIG. 3 and has a bottomed cylindrical shape. The tubular member 10 is provided between the supply unit 2 and the first flow path 31, has one opening 11 on the upper end side, and a plurality of small diameter openings 12 on the bottom surface on the lower end side. have. The molten metal Q that has passed through the tubular member 10 is divided into a plurality of parts by the opening 12. For this reason, the molten metal Q can be divided into finer droplets Q1 in the primary division. That is, the plurality of openings 12 function as a dividing unit that divides the molten metal Q substantially uniformly along the circumferential direction of the lower end surface of the cylindrical member 10.

From this point of view, it is preferable that the plurality of openings 12 are provided so as to be uniformly distributed at the bottom (lower end surface) of the cylindrical member 10. Thereby, since the molten metal Q is divided into smaller and more uniform before primary splitting, the droplet Q1 having a finer and narrower particle size distribution can be obtained by the primary splitting.
The inner diameter of the opening 12 is not particularly limited, but is preferably about 1 to 10 mm, and more preferably about 1 to 5 mm. By setting the inner diameter of the opening 12 within the above range, it is possible to prevent the opening 12 from being blocked by the solidified product of the molten metal Q or the surface tension of the molten metal Q, and the fine droplet Q1 Can be formed.

As shown in FIG. 1, such a cylindrical member 10 is provided concentrically with the discharge port 23 and coincides with the central axis O of the first flow path 31.
The upper end of the cylindrical member 10 is in contact with the bottom 21 of the supply unit 2 as shown in FIG. Thereby, the air G which flows in from the upper direction of the cylindrical member 10 so that it may be drawn in by fall of the molten metal Q can be interrupted | blocked. As a result, the influence (disturbance of the route of the molten metal Q, temperature decrease, oxidation, etc.) caused by the contact of the molten metal Q with the air G can be suppressed.

On the other hand, the lower end of the tubular member 10 is disposed in the middle of the first flow path 31. Thereby, the molten metal Q is supplied through the inside of the cylindrical member 10 to the vicinity of the portion 331 that is the most decompressed region. As a result, the influence of contact between the molten metal Q and air can be reliably prevented or suppressed.
At this time, the lower end of the cylindrical member 10 is more preferably located in the vicinity of the primary splitting position. Thereby, while the molten metal Q is discharged from the lower end of the cylindrical member 10, primary splitting will be produced. As a result, a particularly fine droplet Q1 is obtained.

The primary splitting position changes depending on the composition and viscosity of the molten metal Q in addition to the shape and angle of the inner diameter gradually decreasing portion 33 and the orifice 34 of the nozzle 3, and accordingly, the lower end of the cylindrical member 10 is accordingly changed. It is preferable to adjust the position.
In general, the primary splitting position is often located in the most decompressed region of the first flow path 31 or in the vicinity thereof. Therefore, the primary splitting position in this embodiment is located in the vicinity of the portion 331. Thereby, in this embodiment, since the lower end of the cylindrical member 10 is located in the vicinity of the said part 331, the molten metal Q discharged from the cylindrical member 10 is primarily split immediately after discharge. For this reason, since the molten metal Q can be primarily split at a higher temperature and in a low viscosity state, a finer droplet Q1 can be obtained, and finally a finer metal powder R can be obtained.

Further, if the composition of the molten metal Q can be amorphous, the cooling rate of the droplet Q1 is increased by reducing the size of the droplet Q1. As a result, the atomic arrangement in the liquid state can be more reliably maintained, and an amorphous metal powder R having a higher degree of amorphization can be obtained.
Moreover, it is preferable that the upper end of the cylindrical member 10 is airtightly connected to the supply unit 2. Thereby, the inflow of the air G from the upper part of the cylindrical member 10 can be prevented more reliably. Further, the lower end of the tubular member 10 is depressurized by the flow of the air G flowing below the tubular member 10. As a result, since the molten metal Q is discharged so as to be sucked out from the opening 12 of the cylindrical member 10, it is possible to prevent the solidified material from adhering to the periphery of the opening 12.

The dimensions of such a cylindrical member 10 are appropriately set according to the size of the discharge port 23, that is, the outer diameter of the molten metal flow that falls, and the transverse area of the lumen is about 1 to 400 mm ^2. Is preferable, and it is more preferable that it is about 5-80 mm < ² >. By using the cylindrical member 10 having such a size range, the metal powder production method of the present invention can efficiently produce a metal powder R that is particularly fine and has a uniform particle diameter.
In addition, in this embodiment, although the supply part 2 and the cylindrical member 10 are contacting, these may be spaced apart.

Moreover, it is preferable that the cylindrical member 10 has a cylindrical shape. Thereby, for example, when the droplet Q1 falls along the lower end surface of the cylindrical member 10, the droplet Q1 may be distributed in the horizontal direction so as to contact the substantially conical fluid jet S1 evenly. it can. As a result, the scattering and cooling of the fluid jet S1 with respect to the droplet Q1 are uniformly performed as a whole, and a metal powder R having a uniform particle diameter is obtained.
Furthermore, the flow of the air G flowing into the first flow path 31 is unintentionally disturbed by the tubular member 10, and as a result, it is possible to prevent the route through which the molten metal Q falls from changing.
Note that the number of the plurality of openings 12 provided on the bottom surface of the cylindrical member 10 may be one, and the cylindrical member 10 may have a cylindrical shape having no bottom surface.

4 and 5 are partial cross-sectional views schematically showing other configuration examples of the cylindrical member.
The cylindrical member 10 shown in FIG. 4 has the annular convex part 13 along the circumferential direction of the lower end surface. Such a convex portion 13 can be simply used as a dividing means for dividing the molten metal Q that has passed through the lumen portion of the cylindrical member 10 substantially uniformly along the circumferential direction of the lower end surface of the cylindrical member 10. It can be done. By this dividing means, the droplet Q1 falls uniformly on the entire first flow path 31, so that the droplet Q1 can contact the cone-shaped fluid jet S1 almost evenly and is high. Cooled and solidified with cooling efficiency. As a result, a homogeneous metal powder R can be obtained more reliably.

In addition, as described above, since the convex portion 13 has an annular shape, the convex portion 13 serves as a dividing unit that can divide the molten metal Q more uniformly.
When the molten metal Q that has passed through the cylindrical member 10 reaches the opening 12 at its lower end, it moves to the inner wall of the cylindrical member 10 by its surface tension, and travels along the inner wall to the lower end of the convex portion 13. To reach.

Furthermore, the convex part 13 shown in FIG. 4 has a sharp lower end. Thereby, since the contact area of the droplet Q1 and the cylindrical member 10 can be reduced, the droplet Q1 can be quickly separated from the cylindrical member 10. As a result, the time during which the droplet Q1 stays on the surface of the cylindrical member 10, that is, the time during which the droplet contacts the air G can be further shortened.
The cylindrical member 10 shown in FIG. 5 has a plurality of protrusions 14 provided substantially evenly along the circumferential direction of the lower end surface thereof. Thereby, the protrusion 14 functions as a dividing unit that divides the molten metal Q that has passed through the inner cavity of the cylindrical member 10 substantially uniformly along the circumferential direction of the lower end surface of the cylindrical member 10. As a result, the same effect as the above-mentioned convex part 13 is produced.

  In addition, since a plurality of protrusions 14 are provided along the circumferential direction of the lower end surface of the cylindrical member 10, for example, even when the axis of the cylindrical member 10 is slightly inclined with respect to the vertical direction, Without Q1 concentrating on a part of the lower end surface of the cylindrical member 10, it becomes easy to form the droplets Q1 almost uniformly along the circumferential direction. As a result, the droplet Q1 can be dropped uniformly over the entire first flow path 31.

Other examples of the dividing means include grooves or ridges provided on the inner peripheral surface of the cylindrical member 10 in parallel with the shaft. The same effect as described above can also be obtained by the division assisting means having such a configuration.
The material of the cylindrical member 10 may be any material having heat resistance that does not change or deteriorate even when it comes into contact with the molten metal Q. For example, various ceramic materials such as alumina and zirconia, and various heat resistances such as tungsten A metal material etc. are mentioned.

Among these, a ceramic material is particularly preferable as the constituent material of the cylindrical member 10. A ceramic material is preferable because it has particularly high heat resistance and hardly undergoes chemical changes such as oxidation. In addition, since the ceramic material is relatively excellent in heat insulation (having relatively low thermal conductivity), it also has an advantage of suppressing the temperature drop of the molten metal Q.
In the present embodiment, the case where the fluid is water S has been described as a representative. As the fluid, various liquid or gaseous refrigerants can be used, but liquid is preferable as in the present embodiment. Since the liquid fluid has a larger specific gravity and heat capacity than the gaseous fluid, when the liquid fluid comes into contact (secondary splitting) with the molten metal Q, the molten metal Q can be further refined and efficiently cooled in a short time. it can. Further, since the liquid fluid draws more air G, the pressure (atmospheric pressure) of the first flow path 31 can be further reduced, and further miniaturization by primary division can be further promoted.

Moreover, the molten metal Q may contain any element, for example, the thing containing at least one of Ti and Al can also be used. These elements are highly active, and the molten metal Q containing these elements is easily oxidized by forming contact with the air G for a short time to form an oxide film, which makes it difficult to miniaturize. Yes. The metal powder manufacturing method of the present invention can easily pulverize such molten metal Q.

By using the metal powder manufacturing apparatus 1 as described above, it is possible to efficiently manufacture a metal powder R that is fine and has a uniform particle diameter.
When such a high-quality metal powder R is, for example, a grinding material for grinding the surface of the member to be treated, each particle is ejected when the grinding material, that is, the metal powder produced according to the present invention is sprayed on the member to be treated. The kinetic energy of the material becomes substantially constant, and grinding can be performed with a constant grinding force based on this kinetic energy. Thereby, a member to be processed can be processed with high processing accuracy.
Furthermore, when the metal powder produced according to the present invention is used, for example, as a raw material powder for forming a molded body, it is possible to prevent the occurrence of molding defects such as voids and to obtain a high-density molded body. . And a sintered compact with high dimensional accuracy can also be obtained by baking this molded object.

Second Embodiment
Next, 2nd Embodiment of the metal powder manufacturing apparatus used for the metal powder manufacturing method of this invention is described.
FIG. 6 is an enlarged detailed view (schematic diagram) showing a part of the second embodiment of the metal powder manufacturing apparatus used in the metal powder manufacturing method of the present invention. In the following description, the upper side in FIG. 6 is referred to as “upper” and the lower side is referred to as “lower”.
Hereinafter, although the second embodiment will be described, the description will focus on the differences from the first embodiment, and the description of the same matters will be omitted.

The metal powder manufacturing apparatus 1 of this embodiment is the same as that of the said 1st Embodiment except the structures of a cylindrical member differing.
In this embodiment, as shown in FIG. 6, a plurality of cylindrical members 10 ′ are provided. Each cylindrical member 10 ′ is arranged so that its upper end is in contact with the bottom 21 of the supply unit 2 and its lower end is located in the middle of the first flow path 31, as in the first embodiment. ing.

Thus, by having comprised the molten metal Q to the 1st flow path 31 via several cylindrical member 10 ', the molten metal Q can be scattered more widely. Thereby, the probability that the formed droplets Q1 are in contact with each other can be reduced, and the particle size of the droplets Q1 can be suppressed or prevented from increasing.
Moreover, each cylindrical member 10 'can take the structure similar to the cylindrical member 10 of the said 1st Embodiment, respectively.

<Third Embodiment>
Next, a third embodiment of the metal powder production apparatus used in the metal powder production method of the present invention will be described.
FIG. 7 is an enlarged detailed view (schematic diagram) showing a part of a third embodiment of the metal powder manufacturing apparatus used in the metal powder manufacturing method of the present invention. In the following description, the upper side in FIG. 7 is referred to as “upper” and the lower side is referred to as “lower”.
In the following, the third embodiment will be described. The description will focus on the differences from the first embodiment, and the description of the same matters will be omitted.

The metal powder manufacturing apparatus 1 of this embodiment is the same as that of the said 1st Embodiment except the structures of a 1st member and a 2nd member differing.
In the first member 4 shown in FIG. 7, a first recess 43 and a first easily deformable portion 44 are formed. Further, the second member 5 is formed with a second recess 53 and a second easily deformable portion 54.

The first concave portion 43 is formed by a part of the inner diameter gradually decreasing portion 33 being lost. The first concave portion 43 reduces the thickness of the first member 4, and the portion where the thickness is reduced can be easily deformed due to a decrease in physical strength thereof, and the first easily deformable portion 44. It becomes.
Further, since the first easily deformable portion 44 can be easily deformed in this way, the first on the central axis O side (the right side in FIG. 7) of the first flow path 31 from the first easily deformable portion 44. The central portion 45 can be easily and reliably displaced around the first easily deformable portion 44. In FIG. 7, as an example of the displacement, the first center portion 45 ′ after the displacement is indicated by a two-dot chain line.

The first recess 43 is formed in an annular shape over the entire circumference of the inner diameter gradually decreasing portion 33. As a result, the first easily deformable portion 44 is formed along the circumferential direction of the inner diameter gradually decreasing portion 33, and thus the first center portion 45 is evenly displaced in any portion in the circumferential direction. Can do.
As shown in FIG. 7, the first recess 43 is located on the inner side (center axis O side) with respect to the boundary 38 between the storage portion 35 and the introduction path 36, that is, on the right side in FIG. .

Moreover, the longitudinal cross-sectional shape of the 1st recessed part 43 has comprised the triangle. Thereby, it can deform | transform so that the two inclined surfaces 431 and 432 of the 1st recessed part 43 may approach. That is, since the first easily deformable portion 44 can be deformed so that the apex angle of the top portion 433 of the first recess 43 is reduced, the first center portion 45 can be easily and reliably displaced. .
The first recess 43 is located on the inner side with respect to the boundary 38 in the illustrated configuration, but is not limited thereto, and may be located on the outer side with respect to the boundary 38.

Moreover, although the longitudinal cross-sectional shape of the 1st recessed part 43 has comprised the triangle in the structure of illustration, it is not limited to this, For example, you may comprise U shape.
The second concave portion 53 is formed by a part of the lower portion 55 of the second member 5 in the vicinity of the orifice 34 being lost. The second concave portion 53 reduces the thickness of the second member 5, and the portion where the thickness is reduced can be easily deformed because its physical strength is reduced, and the second easily deformable portion 54. It becomes.

In addition, since the second easily deformable portion 54 can be easily deformed in this way, the second easily deformable portion 54 of the second member 5 has a second channel closer to the central axis O of the first flow path 31. The central portion 56 can be deformed so as to follow the first central portion 45 ′. In FIG. 7, as an example of the displacement, the second center portion 56 ′ after the displacement is indicated by a two-dot chain line.
Further, the second recess 53 is formed in an annular shape along the circumferential direction of the inner diameter gradually decreasing portion 33. As a result, the second easily deformable portion 54 is formed along the circumferential direction of the inner diameter gradually decreasing portion 33, so that the second central portion 56 is evenly displaced at any portion in the circumferential direction. Can do.
In addition, the 2nd recessed part 53 is located inside the boundary 38, ie, the right side in FIG. 7, as shown in FIG.

Moreover, the longitudinal cross-sectional shape of the 2nd recessed part 53 has comprised the triangle. Thereby, it can deform | transform so that the two inclined surfaces 531 and 532 of the 2nd recessed part 53 may space apart. That is, since the second easily deformable portion 54 can be deformed so that the apex angle of the top portion 533 of the second recess 53 increases, the second center portion 56 can be easily and reliably displaced. .
In addition, although the 2nd recessed part 53 is located inside with respect to the boundary 38 in the structure of illustration, it is not limited to this, You may be located outside with respect to the boundary 38.

Moreover, although the longitudinal cross-sectional shape of the 2nd recessed part 53 has comprised the triangle in the structure of illustration, it is not limited to this, For example, you may comprise U shape.
In the metal powder manufacturing apparatus 1 configured as described above, when the liquid jet S1 is ejected from the orifice 34, the inner peripheral surface 341 and the outer peripheral surface 342 are pressed by the pressure of the water S passing through the orifice 34. For this reason, the orifice 34 tries to expand.

  However, in the metal powder manufacturing apparatus 1 shown in FIG. 7, when the liquid jet S <b> 1 is ejected from the orifice 34, the first central portion 45 is caused by the pressure of the water S passing through the vicinity of the boundary 38, the introduction path 36 and the orifice 34. Is displaced around the first easily deformable portion 44, resulting in a first central portion 45 ′ shown in FIG. Similarly to the first central portion 45, the second central portion 56 is displaced so as to follow the first central portion 45 ′ (the displaced first central portion 45) by the pressure of the water S. The second central portion 56 ′.

  In this way, in the metal powder manufacturing apparatus 1 shown in FIG. 7, the first central portion 45 and the second central portion 56 are displaced (deformed) in the same direction, resulting in the diameter of the orifice 34 ( Expansion of the (interval) will be regulated. Therefore, the size of the orifice 34 can be kept constant, and thus the flow velocity of the liquid jet S1 ejected from the orifice 34 can be reliably kept constant. As a result, regardless of the pressure of the water S, the flow velocity of the liquid jet S1 can be kept constant, and the ability to cool the droplet Q1 by the fluid jet S1 can be kept constant.

  Further, in the metal powder manufacturing apparatus 1 shown in FIG. 7, the flow direction of the air G drawn into the inner diameter gradually decreasing portion 33 is disturbed by the first recess 43 formed in the middle of the inner diameter gradually decreasing portion 33, and is cylindrical. It changes toward the member 10 side. Then, the flow of the air G toward the tubular member 10 side is directed downward along the outer peripheral surface of the tubular member 10. Therefore, in the lower end portion of the cylindrical member 10, a flow of air G is formed in a region closer to the cylindrical member 10, and the pressure drop is further promoted in the vicinity of the lower end portion of the cylindrical member 10. . As a result, the molten metal Q in the tubular member 10 can be sucked out and reliably discharged.

Furthermore, since the primary splitting position is located closer to the lower end of the cylindrical member 10, the molten metal Q can be split primary at a higher temperature and with a lower viscosity. For this reason, finer droplets Q1 can be obtained, and finally, finer metal powder R can be obtained.
Further, if the composition of the molten metal Q is a composition that can be amorphous, the cooling rate of the droplet Q1 is increased by reducing the size of the droplet Q1. As a result, the atomic arrangement in the liquid state can be more reliably maintained, and an amorphous metal powder R having a higher degree of amorphization can be obtained.

The metal powder manufacturing method of the present invention has been described above with reference to the illustrated embodiment. However, the present invention is not limited to this, and for example, each part constituting the metal powder manufacturing apparatus exhibits the same function. It can be replaced with any configuration obtained. Moreover, arbitrary components may be added.
Further, for example, the configuration of the cylindrical member may be a combination of a plurality of configurations described in the above embodiment.

1. Production of metal powder (Example 1)
First, Cu (copper) was melted in a high frequency induction furnace to obtain a melt.
Then, the melt obtained was powdered by atomizer (metallic powder production apparatus) shown in FIG. 1, to obtain Cu powder (metal powder).

Note that the alumina cylindrical member (tubular member) used in the atomizer shown in FIG. 1 is hermetically connected at its upper end to the tundish (supplying unit), while its lower end is a flow path through which the molten metal passes ( It arrange | positioned so that it might be located in the middle of the 1st flow path).
Further, this cylindrical member had an inner diameter of 5 mm (cross-sectional area: 19.6 mm ² ), and water was used as a fluid for cooling the molten metal.

(Example 2)
Cu powder was obtained in the same manner as in Example 1 except that the cylindrical member had an inner diameter of 6 mm (cross-sectional area: 28.3 mm ² ).
(Comparative example)
A Cu powder was obtained in the same manner as in Example 1 except that an atomizer in which the cylindrical member was omitted was used.

2. Evaluation of metal powder About Cu powder obtained by each Example and the comparative example, the standard deviation of the average particle diameter and the particle size distribution was obtained with the laser type particle size distribution meter.
These results are shown in Table 1.

As shown in Table 1, it is recognized that the Cu powder of each example is a powder having a small particle size and a uniform particle size as compared with the Cu powder of the comparative example.
In particular, such a tendency was remarkable in the Cu powder of Example 1.

  DESCRIPTION OF SYMBOLS 1 ... Metal powder manufacturing apparatus (atomizer) 2 ... Supply part 21 ... Bottom part 22 ... Internal space (luminal part) 23 ... Discharge port 3 ... Nozzle 31 ... 1st flow path 32 ... 1st 2 flow path 33... Inner diameter gradually decreasing portion 331... Portion 34... Orifice 341 .. inner peripheral surface 342... Outer peripheral surface 35 .. storage portion 36. First member 41 …… Upper end surface 43 …… First recess 431, 432 …… Slope 433 …… Top portion 44 …… First easily deformable portion 45, 45 ′ …… First central portion 5 …… First Second member 51 ...... Lower end surface 53 ...... Second recess 531, 532 ...... Inclined surface 533 …… Top portion 54 …… Second easily deformable portion 55 …… Lower portion 56, 56 ′ ２ Second center portion 7 …… Cover 10, 10 ′ …… Cylindrical member 11, 12 …… Opening portion 1 3 ... Convex part 14 ... Protrusion part G ... Air (gas) O ... Center axis Q ... Mold metal Q1 ... Droplet R ... Metal powder S ... Water (liquid) S1 ... Liquid jet S2 ... top

Claims (6)

Store the molten metal in the supply section,
The molten metal of the supply unit, with discharges to the lumen of the tubular member which is installed below the supply part, the said molten metal by dividing means provided at the lower end of the tubular member Divided in the circumferential direction of the lower end,
In the flow path that is disposed below the supply portion and into which the lower end portion of the cylindrical member is inserted, an air flow is formed downward along the outer peripheral surface of the cylindrical member, and the cylindrical member By reducing the pressure near the lower end , the molten metal in the cylindrical member is discharged,
The molten metal discharged from the cylindrical member is primarily divided into a large number of droplets,
A liquid fluid is ejected from an orifice that opens at the lower end of the flow path, and the liquid droplets are scattered by colliding with the liquid droplets obtained by the primary division, so that a larger number of finer liquids A method for producing a metal powder, characterized in that the liquid droplets are secondarily divided and the plurality of liquid droplets obtained by the second division are cooled and solidified. The flow path has a shape in which the inner diameter gradually decreases from the upper end toward the middle of the flow path, and gradually increases from the middle toward the lower end, and the liquid fluid is ejected from the orifice to eject the liquid fluid . The method for producing metal powder according to claim 1, wherein the pressure in the vicinity of the lower end is reduced. The metal powder manufacturing method according to claim 1, wherein the cylindrical member has a cylindrical shape. The metal powder manufacturing method according to claim 3, wherein the dividing means has a structure in which the thickness of the lower end portion of the cylindrical member gradually decreases as it goes downward. The metal powder manufacturing method according to any one of claims 1 to 4, wherein the dividing means divides the molten metal substantially equally. The metal powder manufacturing method according to any one of claims 1 to 5, wherein the cylindrical member is disposed such that a lower end portion thereof is positioned near a position where the molten metal is primarily split.

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