JPH0754019A - Production of powder by multistage fissure and quenching - Google Patents

Abstract

PURPOSE:To produce the powder having a uniform particle diameter and high quality in a large amt. at a low production cost and produce the amorphous alloy powder particularly having excellent properties. CONSTITUTION:Molten metal 1 is fissured by an atomizing treatment using an inert gas 3 and the fissured liquid drops of the molten metal are brought into collision against a rotary disk 4, a rotary drum or rotary roll, by which the liquid drops are pulverized. The pulverized liquid drops are brought into contact with a cooling medium 6 and are quenched, by which the liquid drops are solidified into the powder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a powder by obtaining droplets of a molten metal which are atomized by a multi-step splitting treatment, and rapidly cooling and solidifying the droplet.

[0002]

2. Description of the Related Art Conventionally, in a method for producing powder by rapidly cooling a molten metal, the atomization treatment of a melt is generally performed, but the produced powder has a wide particle size distribution. Therefore, there is a problem in that the existence of particles having a large particle diameter cannot be avoided.

Further, since the cooling rate of the melt particles becomes smaller as the particle size becomes larger, when the rapid cooling treatment method is used as a method for producing the powder of the amorphous alloy having a large particle size, Since uniform rapid cooling is not performed, there is a problem that a single-phase powder made of amorphous cannot be obtained.

[0004]

DISCLOSURE OF THE INVENTION In the prior art,
Since the powder prepared as described above has a wide particle size distribution, the existence of particles having a large particle size is unavoidable, and a single-phase powder composed of an amorphous material cannot be obtained. It was researched and developed for the purpose of solving problems. That is, the present invention is to maintain the particle size distribution of the obtained powder in a narrow range to produce a powder having a uniform particle size.
It is also intended to obtain an amorphous powder having a single phase.

[0005]

According to the present invention, finely divided droplets are obtained by dividing a molten metal in multiple stages, and the droplets are brought into contact with a cooling medium such as gas, liquid nitrogen, water and oil. It is a method of producing powder by rapidly cooling and solidifying.

According to the present invention, by appropriately adjusting the processes in processes such as spray splitting, collision splitting, and quench solidification,
Since the particle diameter and particle shape of the obtained powder can be freely controlled, a large amount of powder of high quality and low manufacturing cost can be manufactured. And the present invention is
This is an excellent method for producing an amorphous alloy powder having particularly excellent properties.

Next, the present invention will be specifically described with reference to the drawings.

The principle of the device of the present invention is shown in FIGS. 1, 2 and 3. The powder production process of the present invention includes a process of atomizing the liquid droplets by a gas spray of a melt and a high-speed rotating disk, a rotating drum and / or a rotating roll, and a process of forcibly quenching and solidifying the atomized liquid droplets by a cooling medium. It has 3 steps.

The above gas spraying melts raw materials or ingots,
After this is once received by the tundish, a molten metal flow having a small diameter is made through the nozzle 2, and argon or nitrogen gas 3 is jet-collised against the flow to atomize the molten metal, thereby forming the molten metal into droplets. In the step of atomizing the molten metal with the gas of the present invention, the temperature of the molten metal is set higher than that in the conventional spraying method and kept in an overheated state in order to prevent the solidification of droplets.

The superheat temperature (ΔTs) and the distance (H) from the spray point to the disk are strongly related to the particle size and shape of the powder to be produced. There are optimum values for ΔTs and H depending on the alloy. For example, Al and Al-Si alloys have ΔTs of 250-300K and H of 75-1.
It is 00 mm.

The molten metal atomized into droplets is shown in FIG.
As shown in FIGS. 2 and 3, the disk 4, the drum 8 and / or the roll 5, which are rotating at a high speed, collide with each other, and the droplets are further divided and scattered to be atomized. Such fragmentation and scattering is carried out a plurality of times as required as shown in FIG. 2 or FIG. 3, and finally the atomized droplets are spheroidized by the surface tension and then rapidly cooled by the cooling medium 6. The obtained powder is taken out together with the cooling medium.

On the other hand, without using a disc, the first
The average particle size of the powder produced only by the gas spraying of 10 is 10
0-150 μm, and the cooling rate of the powder is about 10
Was ² -10 ³ K / s. Also, without using gas atomization,
When the disc and the drum are rotated and the first split droplet formation is performed by the disc and the second split droplet formation is performed by the drum, powder having an average particle size of 10 to ¹⁵ μm is obtained, and the cooling rate is 10 ⁵ −. It was 10 ⁶ K / s.

The average particle size of the powder produced through the three steps of the gas atomization, the rotating disk and the rotating roll in FIG. 2 of the present invention is 3-8 μm, and the cooling rate is 10 ⁶ -10 ⁷ k / has reached s. In contrast, Figure 2
In the case of the device shown in Fig. 1, the average particle size of the powder obtained is 30- when the final disc disruption is not carried out.
The average particle size of the powder was 35 μm, and the average particle size of the produced powder was 10 to 15 μm when gas was not sprayed and a rotating roll and a disk were used.

[0014]

EXAMPLES The present invention will now be described with reference to examples. Figure 1
Powders of the alloys shown in Table 1 were produced using the powder production apparatus by rapid cooling shown in. △ Ts is 260K, H is 75m
m, argon gas spray pressure is 1 MPa, nozzle diameter is 2.5 mm, disk rotation speed is 5000 rpm
Met.

In the case of pure Al, water was used as a cooling medium, and the produced powder had an average particle size of 8 μm and had a good spherical particle shape. Its specific surface area is 2400 cm
It reached ² / g. Further, in the case of the Fe-Si-B alloy, the average particle diameter was 16 μm, and the shape was a spherical particle shape, and an amorphous single phase powder was obtained. The other characteristics are as shown in Table 1.

[0016]

[Table 1]

[0017]

In the conventional method for producing powder by rapid cooling of molten metal, it was unavoidable that the produced powder had a wide particle size distribution and large particles were present. In the present invention, the particle size and particle shape of the obtained powder can be freely controlled by adjusting the processes in the processes such as spray splitting, collision splitting, and quench solidification, so that the quality and the low It is possible to produce a large amount of powder at a manufacturing cost. The present invention is excellent as a method for producing an amorphous alloy powder having particularly excellent properties.

[Brief description of drawings]

FIG. 1 is a diagram showing an apparatus including a gas atomizing mechanism, a rotary disk and a rotary drum splitting mechanism, which is an embodiment of the present invention.

FIG. 2 is a view showing an apparatus including a gas atomizing mechanism, a rotating roll and a rotating disk splitting mechanism according to another embodiment of the present invention.

FIG. 3 shows a gas atomizing mechanism according to another embodiment of the present invention and 3
FIG. 3 is a view showing an apparatus provided with a splitting mechanism composed of a rotating roll of a book.

[Explanation of symbols]

 1: Molten metal 2: Nozzle 3: Inert gas 4: Rotating disk 5: Rotating roll 6: Cooling medium 7: Alloy droplets 8: Rotating drum

Claims (4)

[Claims] 1. A method for producing powder, in which droplets obtained by atomizing a molten metal by multi-step splitting are rapidly solidified by a cooling medium. 2. A molten metal is sprayed with an inert gas to be divided, and the divided molten metal droplets are successively collided and divided by a rotating disk and a rotating drum to be atomized, and the atomized droplets are brought into contact with a cooling medium. A method for producing a powder, characterized in that the powder is solidified by rapidly cooling it. 3. A molten metal is sprayed with an inert gas to be divided, and the divided molten liquid droplets are successively collided and divided by a rotating roll and a rotating disk to be atomized, and the atomized droplets are brought into contact with a cooling medium. A method for producing a powder, characterized in that the powder is solidified by rapidly cooling it. 4. The molten metal is sprayed with an inert gas to be split, and the split molten liquid droplets are successively collided and split into three rotary rolls to be atomized, and the atomized droplets are brought into contact with a cooling medium. A method for producing a powder, characterized in that the powder is rapidly cooled and solidified to obtain a powder.