JPH0368922B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for producing an amorphous alloy powder by spraying a high-speed liquid onto a flowing molten alloy. [Prior Art] Conventionally, amorphous alloys have been manufactured by various methods depending on their shape. When producing amorphous alloys that become flaky when cooled, the gun method, piston-anvil method, torsion-catapult method, etc. are used. In addition, when manufacturing ribbons continuously, a centrifugal method, a single roll method, a twin roll method, etc. are used. Furthermore, when producing fine wires, methods such as water spinning and rotating liquid spinning are used. However, the amorphous alloys obtained by these methods have a specific shape, and it is very difficult to manufacture parts with arbitrary shapes. On the other hand, a powder metallurgy method in which powder is compacted using a press or the like is known as a method for manufacturing parts with complex shapes. Also, known methods for producing amorphous alloy powder include a spray method, a cavitation method, an injection method in a rotating liquid, and an atomization method. However, in this method, the cooling rate is not sufficient, and only fine particles become amorphous, resulting in a poor yield and the degree of amorphization being non-uniform. Moreover, since the shape of the obtained amorphous alloy powder is spherical or flake-like, there is little entanglement between the powders even when compacted, and semi-finished materials, parts, etc. can be manufactured without using a binder. I can't. Therefore, it is difficult to industrially utilize powders obtained by these methods in powder metallurgy. The inventor of the present invention obtained the following knowledge as a result of repeated research to solve this problem. The shape of the powder obtained by pulverizing molten metal is greatly influenced by the pulverization characteristics determined by the shearing force of the high-speed liquid against the molten metal flow, and the processes leading to solidification and cooling after pulverization. In particular, the process from solidification to cooling is closely related to the physical properties of the molten metal and welding.
The shape of the powder is affected by viscosity, surface tension, etc. during the cooling process. Moreover, the relative factors between these physical properties and the cooling rate have a great influence on the amorphization of the powder. [Technical Problems to be Solved by the Invention] The present invention was made based on this knowledge, and the powder after molten metal powder is sucked to destroy the vapor film around the powder and increase the cooling rate. The purpose of this is to stably and efficiently obtain a powder that is irregularly shaped to the extent that it can be compacted and is completely amorphous. [Means for Solving Technical Problems] In other words, the present invention includes a step of causing a molten metal of an alloy that becomes amorphous to flow down through pores, and a process of blowing a high-speed liquid onto the flowing molten metal to powder the molten metal and rapidly cool it. A step of solidifying, a step of arranging a suction tube around the point where the molten metal is to be powdered and suctioning with a pressure difference of 20 mmH ₂ O to 200 mmH ₂ O, and a step of arranging a powder receiver below the suction tube, The process includes the steps of once applying the solidified amorphous powder to the powder receiver, and dropping the amorphous powder into a tank containing liquid after applying the solidified amorphous powder to the powder receiver. The present invention is characterized by producing an amorphous alloy powder that is entirely irregular in shape, consists of an amorphous single phase, and is compactable. The present invention will be described below with reference to illustrative embodiments. The drawing shows an example of an amorphous alloy manufacturing apparatus. In this device, a crucible 2 is arranged on a spray tank 1, and a spray nozzle 3 and a suction pipe 4 are installed below the crucible 2.
and a powder receiver 5 are arranged in this order, and an overflow pipe 6 attached to the spray tank 1 is connected to a discharge tank 7. The crucible 2 is used to hold a molten alloy to be amorphized, and has pores formed at the bottom thereof. This alloy mainly contains approximately 15 to 35 atomic percent of transition metal elements.
Amorphous alloys containing metalloid elements (B, C, Si, P, Ge, etc.) and intermetallic types such as transition metal-transition metal systems, transition metal-metal systems, metal-metal systems, and metal-rare earth systems Examples include compound alloy types. The spray nozzle 3 is, for example, an annular ring nozzle that spouts high-speed liquid such as water, and is designed to focus the high-speed liquid at point a. The intersection angle of this high-speed liquid varies depending on the aperture diameter of the spray nozzle, the speed of the high-speed liquid, and the diameter and length of the suction tube 4, but is preferably 30° to 100°. Further, the speed of the high-speed liquid depends on the spray pressure P, and is preferably 80 Kgf/cm ² or more. Furthermore, the suction tube 4 is provided so as to surround point a,
It is located above the overflow pipe 6. The smaller the diameter of this suction tube 4, the faster the cooling rate can be achieved; however, if the diameter is too small, the powder after powdering will adhere to the inner wall of the suction tube 4, making it difficult to continue powdering. 0.2~3.0 of opening diameter
About double that is preferable. Also, the length needs to be at least 10 cm, as the suction effect will be reduced if it is too short. Further, the shape may be any shape, but a cylindrical shape is preferable. Furthermore, the pressure difference between the upper chamber 8 and lower chamber 9 of the powder mist tank 1 is 20 mmH ₂ O ~
_200mmH2O , preferably _40mmH2O to _200mmH2O . The reason for this is that if the pressure difference is too small, the suction effect will be small and the initial objective cannot be achieved, but if the pressure difference is too large, it will be difficult for the liquid and powder to come into contact with each other, making it impossible to obtain the desired cooling rate, resulting in complete amorphous formation. This is because it becomes difficult to do so. Further, the powder receiver 5 is provided directly below the suction pipe 4 and above the overflow pipe 6. Powder receiver 5
The structure is not particularly limited, and may be integrated with the suction tube 4 or separated. [Operations and Effects of the Invention] According to the method of the present invention, the molten metal flows down from the pores of the crucible 2, and the flowing molten metal is pulverized by the high-speed liquid jetted from the spray nozzle 3. At this time, the powdered alloy powder is forcibly pushed out downward by the vacuum action of the suction tube 4. This causes the high-speed liquid to act more strongly on the alloy powder, causing it to become disordered. Furthermore, the vapor film generated around the powder is destroyed and the cooling rate of the powder is significantly increased. Then, the powder is applied to the powder receiver 5 and then captured in the spray tank 1 or the discharge tank 7, followed by the removal of the adhering fluid to obtain an amorphous alloy powder. In this case, since the powder is once applied to the powder receiving body 5, the fluctuation of the water surface in the spray tank 1 is suppressed and the pressure difference between the upper and lower chambers is prevented.As a result, the desired pressure difference can always be obtained and powderization can be stabilized. It can be done. [Example] Next, an example of the present invention will be described. Example 1 5 kg of an alloy having a composition of 80 atomic % Fe, 13 atomic % P, and 7 atomic % C was melted and allowed to flow down from a nozzle at a molten metal temperature of 1400°C. Water was ejected onto this falling molten metal at a spray pressure of 125 kg, a flow rate of 290/min, and a spray intersection angle of 65°, which was further suctioned with a suction tube and applied to a particle receiver to obtain an amorphous alloy powder (No. 1). In this case, the suction tube has an inner diameter
50mmφ, length 400mm, differential pressure between upper and lower chambers 100mm
It was made into _H2O . The particle size distribution of the amorphous alloy powder thus obtained was investigated, and the results are shown in Table 1. For comparison, an amorphous alloy powder (No. 2) was produced under the same conditions without using a suction tube or powder receiver, and its particle size distribution was investigated. The results are also listed in Table 1.

[Table] Next, among the powders according to the present invention (No. 1), those with +100 mesh, -100 to +300 mesh, and -350 mesh were subjected to X-ray diffraction to determine whether they had become amorphous or not. The result is shown in Figure 2 A (+100 meters)
and shown in the same figure (-350 mesh). Furthermore, the conventional powder (No. 2) was similarly subjected to X-ray diffraction to determine whether it had become amorphous. The result is the third
Shown in Figure A (+100 mesh) and Figure B (-350 mesh). From FIG. 2 and FIG. 3, it can be seen that in the case of the present invention, no crystalline diffraction pattern is observed, and the diffraction pattern is broad, indicating that the diffraction pattern is amorphous.
Although not shown, it was found by similar X-ray diffraction that the meshes of the present invention were amorphous, while the conventional meshes were crystalline. Next, the degree of amorphization of each amorphous alloy powder was investigated by differential thermal analysis. The results are shown in Table 2.

Table 2 shows that complete amorphization can be achieved by the method of the present invention. In addition, the shape of each amorphous alloy powder (No. 1, No. 2) was examined using a microscope, and its schematic diagrams are shown in FIG. 4A (invention powder) and FIG. 4B (conventional powder). It can be seen from FIG. 4 that the alloy powder of the present invention has an irregular shape. Next, the apparent density (AD) and fluidity (FR) of the powder according to the present invention (No. 1) and the conventional powder (No. 2)
The results of the investigation are shown in Table 3.

[Table] From the above table, it can be seen that the powder of the present invention has a significantly lower apparent density than the conventional powder, poor flowability, and is significantly irregular compared to the conventional powder. Example 2 Alloy 5 of 75 at% iron, 10 at% Si, and 15 at% B
Kg was dissolved and an amorphous alloy powder was produced under the same conditions as in Example 1. Table 4 shows the degree of amorphization.

[Table] Example 3 Alloy 5 with 75 at% iron, 15 at% Si, and 10 at% B
Kg was dissolved and an amorphous alloy powder was produced under the same conditions as in Example 1. Table 5 shows the degree of amorphization.

[Table] Example 4 4.0 kg of an alloy containing 80 atomic% iron and 20 atomic% boron was melted, the molten metal temperature was 1400℃, the spray pressure was 100kg/cm ² , the flow rate of water was 250/min, the spray intersection angle was 40 degrees, and the suction pipe was Inner diameter 40mmφ, length 500mm, pressure difference between upper and lower chambers
A powder was prepared at 70 mm H ₂ O. The degree of amorphization is shown in Table 6.

[Table] Example 5 5.0 kg of an alloy of 40 at% iron, 40 at% nickel, and 20 at% boron was melted, molten metal temperature 1400℃, spray pressure 110Kg/cm ² , water flow rate 260/min, spray intersection angle.
Powder was prepared at 50 degrees, the suction tube had an inner diameter of 50 mmφ, a length of 500 mm, and a pressure difference between the upper and lower chambers of 85 mmH ₂ O.
Table 7 shows the degree of amorphization.

[Table] Example 6 Alloy 5.0Kg of 68 at% iron, 10 at% chromium, 2 at% molybdenum, 13 at% phosphorus, and 7 at% carbon
melted, molten metal temperature 1400℃, spray pressure 120Kg/cm ² ,
Powder was produced at a water flow rate of 270/min, a spray intersection angle of 68 degrees, a suction tube with an inner diameter of 50 mmφ and a length of 450 mm, and a pressure difference between the upper and lower chambers of 100 mmH ₂ O. Table 8 shows the degree of amorphization.

[Table] As explained above, according to the present invention, by increasing the cooling rate by installing a suction tube, it is possible to obtain a completely amorphous alloy powder, and also to make the alloy powder irregular. It can be shaped. Therefore, this alloy powder can be compacted, formed between rolls, extruded, etc. without using a binder.
It has remarkable effects and can be used in new applications that cannot be made with conventional amorphous alloys, such as highly corrosion-resistant materials. Further, by providing a powder receiver, stable powder can be produced. Moreover, it can be manufactured efficiently with a simple structure in which a suction tube and a powder receiver are provided in a conventional device. Note that the method of the present invention can also be used for producing ultra-quenched alloy powder.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an example of an apparatus for manufacturing amorphous alloy powder according to the method of the present invention, FIGS. 2A and 2B are diagrams showing X-ray diffraction results of the alloy powder of the present invention,
Figures 4A and 4B are diagrams showing the X-ray diffraction results of the conventional alloy powder, Figure 4A is a schematic diagram of the alloy powder of the present invention, and Figure 4B is a schematic diagram of the conventional alloy powder. 1... Spray tank, 2... Crucible, 3... Spray nozzle, 4... Suction pipe, 5... Powder receiver, 6...
...overflow pipe, 7...discharge tank.

Claims (1)

[Scope of Claims] 1. A step in which a molten metal of an alloy that becomes amorphous is allowed to flow down through pores, a step in which a high-speed liquid is sprayed onto the flowing down molten metal to pulverize the molten metal and rapidly solidify it, and a step in which the molten metal is rapidly solidified into powder. Place a suction tube around the area where
A step of suctioning with a pressure difference of 20mmH ₂ O to 200mmH ₂ O, a step of arranging a powder receiver below the suction tube and once applying the solidified amorphous powder to this powder receiver, After applying it to a receiver, the amorphous powder is dropped into a tank containing a liquid. A method of producing an amorphous alloy powder.