KR100237155B1 - Method and device for manufacturing soft magnetic powder - Google Patents

Abstract

Ingots are prepared by dissolving the master alloy material in a vacuum state using centrifugal force and rapid cooling principle. The present invention relates to an apparatus for producing high-performance soft magnetic metal alloys and intermetallic compound magnetic powders that can obtain soft magnetic metal powders, and a method of manufacturing the same, and a soft magnetic powder produced by the method. The vacuum chamber main body 12 has a branch, the vacuum chamber 14 formed by the vacuum chamber main body 12, the electrode 20 which is installed in the said vacuum chamber 14 in order to generate a plasma arc, and this electrode ( A mother alloy ingot 30 rotatably mounted on a center line of the center 20, a rotation shaft 33 for rotating the mother alloy ingot 30, and Sealing part 60 for maintaining the airtightness between the vacuum chamber main body 12 and the rotating shaft 33, and the sealing part 60 in the vacuum chamber 14 while supplying lubricating oil to the sealing part 60 Since the oil supply pump 80 for supplying a predetermined inert gas through the, and the powder collector 25 is installed in the lower portion of the vacuum chamber body 12 to collect the powder of any composition Even soft magnetic materials of alloy or intermetallic compound composition can produce powders with excellent soft magnetic properties, and in the process of operation, one-time initial supply without inert gas is required to generate plasma arc. Good workability, low consumption of raw materials due to the use of non-consumable tungsten electrode, alloy ingot which is anode without loss of rotational force even in high vacuum atmosphere It can rotate at a high speed to maximize the productivity.

Description

Apparatus and method for manufacturing soft magnetic powder

The present invention relates to the production of soft magnetic powder, and in particular to dissolve the mother alloy material in a vacuum state using centrifugal force and rapid cooling principle to produce an ingot, and then to re-dissolve the surface of the alloy by plasma arc in a vacuum chamber. The present invention relates to an apparatus for producing a high performance soft magnetic metal alloy and an intermetallic compound magnetic powder capable of spherically obtaining soft magnetic metal powders by centrifugal force due to surface energy of an instantaneous melting material and ingot rotational force, and a method of manufacturing the same.

Conventionally, some techniques for obtaining metal powder by centrifugal force have been disclosed as described below.

First, after melting the material in the conductive crucible, the crucible is rotated at high speed and arc is generated by the electrode in the direction facing the molten metal.

Second, a method of producing spherical powder by melting and alloying a material by an electron beam and then dropping the droplets generated in the molten metal onto a rotating disk cooled by cooling water while rotating at high speed.

However, the above methods can be produced on an experimental scale, but there are problems in practical use due to the lack of productivity in the mass production scale.

Recently, a technique using centrifugal force while directly rotating an electrode capable of generating an arc has been disclosed. This technique produces an alloy from an ingot and then turns the ingot into an anode that can be melted in an arc, while another cathode generating a plasma arc is used as a cathode. In this way, the anode ingot facing the arc is rotated at high speed while the alloy of the ingot melts and solidifies into a spherical alloy powder.

According to the above technology, high-quality alloys and intermetallic compounds can be produced in powder form, and arc electrodes are used for non-consumable tungsten. Therefore, in order to generate the plasma arc, it is necessary to continuously supply the inert gas to generate the plasma to the cathode electrode, there is a problem that the productivity of the powder produced is bad.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a soft magnetic powder production apparatus and a method for manufacturing the soft magnetic powder having high performance at low cost.

1 (a) and 1 (b) show the apparatus for producing soft magnetic powder of the present invention. FIG. 1 (a) is a front view and FIG. 1 (b) is a side view.

2 is a cross-sectional view showing a cathode and an anode located inside the apparatus of the present invention.

Figure 3 is an enlarged cross-sectional view showing a high vacuum sealing portion attached to a rotating shaft for rotating the anode of the present invention.

4 (a) and 4 (b) show the oil supply pump of the present invention. FIG. 4 (a) is a sectional side view and FIG. 4 (b) is a front view.

5 is an explanatory diagram schematically showing the generation of plasma arc used in the present invention.

6 is an explanatory diagram for explaining the interaction between the plasma arc (negative electrode) and the ingot (positive electrode) used in the present invention.

* Explanation of symbols for main parts of the drawings

10: soft magnetic powder manufacturing apparatus 12: vacuum chamber body

17a, 17b: double wall 14: vacuum chamber

15: powder collection tube 16: powder collection unit

17: opening and closing door 17 ′: hinge

18: drive motor 19: see-through window

20: electrode (tungsten electrode) 30: master alloy ingot

32: ingot manipulater 33: high speed rotation axis

40: rotary pump 42: high speed DC motor

44: diffusion pump

60: sealing mechanical (vacuum mechanical seal) 63: rotary sealing

64: SiN (Silicon Nitride) Gasket

65 Graphite gasket 67 Oil inlet

68: floating seat 70: O-ring

72: large bearing 74: fixed pin

80: oil supply pump 81: funnel

82 gas inlet 83 oil storage chamber

84: spring valve 85: oil exhaust port

86: ball valve 87: pressure gauge

89: level gauge 90: injection hole

92 outlet

An apparatus for producing soft magnetic powder for achieving the above object includes a vacuum chamber main body having a wall of a circular cross section, a vacuum chamber by the vacuum chamber main body, an electrode installed in the vacuum chamber so as to generate a plasma arc, and the electrode; A master alloy ingot rotatably disposed opposite to a center line of the master alloy, a high speed rotation shaft for rotating the master alloy ingot, a sealing portion for maintaining rotational tightness between the vacuum chamber body and the high speed rotation shaft, and the sealing portion It is composed of an oil supply pump for supplying lubricating oil and supplying an inert gas into the vacuum chamber through the sealing section, and a powder collecting section installed under the vacuum chamber body to collect powder. In the above configuration, the vacuum chamber and the powder collecting unit is preferably to communicate with each other through the flange-type powder collecting tube to collect the powder produced, the vacuum chamber front portion is installed to open and close the door for cleaning and repairing, ingot attachment work It is preferable that it is done.

Preferably, the ingot is fixed by an ingot holder, and the electrode for generating a plasma arc is preferably a tungsten electrode, and the movable electrode is provided with a driving motor for driving the electrode. It is preferable that the vacuum chamber be further provided with a see-through window through which the vacuum chamber can look into the inside, and the opening / closing door is made of an opening / closing method by a hinge, and a mother alloy which is provided on the center line of the electrode. The ingot is fixed by the ingot holder of the chuck fixing method, the sealing part includes an oil suction port into which the lubricating oil is sucked, a rotary sealing part and a rear space part which are front half spaces, at least five O-rings for airtightness, and the rotating shaft It is preferable to include a bearing bearing the bearing.

The vacuum in the vacuum chamber may be performed by using a pump including a rotary pump for initial vacuum, a high-speed DC motor, and a diffusion pump for maintaining a high vacuum, and the vacuum chamber body has a double wall structure made of stainless steel. Cooling the vacuum chamber by supplying cooling water between the double walls, the opening and closing door is of a stainless double wall structure, the exhaust chamber is attached to the vacuum chamber for adjusting the degree of vacuum inside, The supply of lubricating oil required for the rotation of the master alloy ingot is supplied from an oil supply pump connected to a sealing portion, the oil supply pump includes an oil exhaust chamber and an oil storage chamber for storing oil, and an inert gas such as argon gas in the vacuum chamber. It includes a gas inlet for supplying the It's a good idea to use barrel oil.

The oil reservoir has a spring valve for automatic supply of oil, an oil exhaust port for oil discharge is formed at the bottom, a ball belt and a pressure gauge are installed for pressure adjustment and detection, and a level gauge for detecting oil level. It includes, the level gauge for detecting the oil level is provided with the inlet and outlet for inlet / outlet of the sealant, the bearing is installed on the sealing portion and the rotating shaft by a plurality of fixing pins desirable.

In addition, the method for producing a soft magnetic powder to achieve the above object, the ingot of any one of the soft magnetic alloy selected from iron (Fe), cobalt (Co), nickel (Ni) -based alloy in a fixed induction furnace. Fabricating into a shape and inserting it into an ingot holder installed at an end of a high speed rotating shaft connected to the inside of the vacuum chamber; and vacuuming the inside of the vacuum chamber to 10 ^-5 to 10 ^-6 Torr vacuum degree; Injecting and maintaining the pressure in the vacuum chamber at 0.3 to 0.6 atm, and slowly rotating the ingot and simultaneously loading 40-60 kw DC power connected from the outside to the plasma arc generating electrode facing the ingot. Generating, and rotating while adjusting the intensity of the generated argon plasma arc through a secondary input current and voltage of 200 to 1500 amps and 40 to 60 volts. Increasing the speed of the ingot from the initial rotational speed of 4,000 to 6,000 rpm to a high speed in the range of 7,000 to 10,000 rpm, and controlling the distance between the electrode and the ingot to artificially form a particle size of the soft magnetic powder. It features.

In addition, the rotation speed of the ingot is controlled by a rotation drive motor for 10,000 rpm, and the ingot uses a diameter of 100 to 200 mm φ and a length of 200 to 600 mm, and the electrode 20 operates as follows. It is characterized by satisfying the range.

Back and forth movement distance = up to 200mm,

Up and down movement distance = up to 70mm,

Left and right moving distance = up to 34 mm.

In the above production method, the soft magnetic powder has an average particle size of 50 to 200 µm, and is characterized by the following equation.

(Where ω is the ingot's angular velocity, D is the ingot's diameter, γ is the surface tension of the molten alloy, and ρ is the density of the molten alloy)

Accordingly, the present invention having the above structure and method is called an improved "Plasma arc rotating electrode process", and powder having excellent soft magnetic properties even in an alloy or an intermetallic compound composition of any composition. Can produce

In addition, an advantage of the present invention is to use a method of initially supplying a non-consumable tungsten electrode without continuously supplying an inert gas and generating a non-consumable tungsten electrode in order to generate a plasma arc in the course of the operation, and even in a high vacuum atmosphere The powder can be prepared by rotating the alloy ingot as the anode at high speed without loss of.

Hereinafter, a soft magnetic powder manufacturing apparatus of the present invention, a manufacturing method thereof, and a soft magnetic powder produced by the manufacturing method thereof will be described in detail with reference to the accompanying drawings.

1 (a) and 1 (b) is a soft magnetic powder manufacturing apparatus of the present invention, the first (a) is a front view, the first (b) is a side view and FIG. 3 is an enlarged cross-sectional view showing a high vacuum mechanical sealing portion attached to a rotating shaft for rotating the positive electrode of the present invention, 4 (a) and 4 (b) is an oil supply of the present invention. 4A is a side cross-sectional view, and FIG. 4B is a front view, and FIG. 5 is a schematic diagram showing the generation of plasma arc used in the apparatus and method for producing the soft magnetic powder of the present invention. It is also.

In these figures, reference numeral 10 denotes a soft magnetic powder manufacturing apparatus, comprising a vacuum chamber body 12 having a wall of a circular cross section, a vacuum chamber 14 formed by the vacuum chamber body 12, and a lower portion of the vacuum chamber body 12. And a powder collector 16 for collecting the powder, and the powder collector 16 and the vacuum chamber 14 communicate with each other through the powder collector tube 15.

Moreover, the opening / closing door 17 which can open and close the said vacuum chamber 14 is provided in the front part of the said vacuum chamber 14. That is, the front and rear doors 17 are provided on the front surface of the vacuum chamber 14 in order to carry out a powder manufacturing process, to clean the interior of the vacuum chamber, to attach ingots, and the like.

A cathode tungsten electrode 20 (hereinafter referred to as 'electrode') generating a plasma arc is installed on the side of the opening and closing door 17, and the master alloy ingot 30 is ingot holder facing the center line of the electrode 20. It is fixed by 32.

The front and rear linear motion distance of this electrode 20 is 200 mm at maximum, and the range of the linear motion of right and left reaches 50-70 mm corresponding to the radial distance of the master alloy ingot diameter. Therefore, a drive motor 18 for driving this electrode 20 is provided on the opening / closing door 17 side.

Reference numeral 17 'is a hinge that is one component of the opening and closing door 17, and 19 is a viewing window through which the vacuum chamber 14 can be seen.

Although not shown, a DC generator for supplying DC current / voltage is installed therein.

The ingot holder 32 is connected to a vacuum mechanical seal 60 for high speed rotation and is rotatable, and the sealing part 60 is supplied to an oil supply pump 80 for supplying lubricating oil required for rotation. It is connected.

Reference numeral 40 is a rotary pump for initial vacuum, and the rotary pump 40 is a high-speed DC motor 42 for rotating the high speed rotary shaft 33 at high speed and a diffusion pump 44 for maintaining high vacuum. Consists of.

The vacuum chamber body 12 is welded by a double wall made of stainless steel, and the cooling chamber 14 can be cooled by supplying cooling water between the double walls.

Of course, the opening and closing door 17 also has a stainless double wall (17a) (17b) structure.

Two or more gas injection tubes are installed on the wall of the vacuum chamber body 12 so that inert gas can be injected at any time, and at the same time, an exhaust gas pipe (vent) is provided to adjust the degree of vacuum in the vacuum chamber 14. Attached.

In FIG. 2, a plasma generating tungsten electrode 20 located inside the vacuum chamber 14 connects the ingot holder 32 and the high speed rotating shaft 33 holding the master alloy ingot 30 to the vacuum chamber 14. Part 60 shows in detail. The ingot holder 32 has a chuck function.

3 shows the details of the sealing part 60. The high-speed rotary shaft 33 connected to the ingot holder 32 is moved at a high speed to the center of the sealing unit 60, and the sealing unit 60 is attached while facing the front surface of the vacuum chamber body 12. Lubricant for high-speed rotation is sucked in from the oil suction port 67 of the sealing part 60, and the lubricant is composed of a rotary sealing part 63, a SiN gasket 64, and a graphite gasket 65, which is a first half space. It is supplied to a floating seat 68.

Since the sealing part 60 is provided with at least five O-rings 70 in order to perfect the airtightness, the sealing part 60 together with the SiN gasket 64 which is a ceramic material installed in two front and rear places, I raise it more.

In addition, a large bearing 72 is provided at the center of the sealing part 60 to assist the high speed rotation of the high speed rotation shaft 33. Reference numeral 66 denotes a packing and 74 denotes a fixing pin installed around the large bearing 72.

4 shows a detailed view of an oil supply pump 80 for supplying lubricating oil to the sealing part 60. The structure and the outline operation will be described together.

The oil supply pump 80 is installed at an upper portion of the funnel 81 for oil supply, and a high vacuum pump oil (silicon system) is injected through the funnel 81 and at the same time, an N ₂ gas inlet ( While N ₂ gas is supplied through 82, the oil is smoothly transported into the oil storage chamber 83 installed at the lower portion. The oil may be injected only by the force of gravity.

The injected oil enters the oil suction port 67 shown in FIG. 3 through the oil discharge port 85 by the strength of the force of the spring valve 84 provided in the oil storage chamber 83.

The pressure of the oil storage chamber 83 is controlled and sensed by the ball valve 86 and the pressure gauge 87, so that the water level can be accurately detected by using a sealant to detect the oil level of the oil storage chamber 83. The level gauge 89 is attached, and for this purpose, an inlet 90 and an outlet 92 for injecting a sealant are installed.

The principle of the powder manufacturing method using the plasma of this invention is demonstrated with reference to FIG. 5 shows a schematic diagram in which the plasma generating electrode 20 as the cathode and the master alloy ingot 30 as the anode are connected to the DC power supply 50.

Soft magnetic powder formed by centrifugal force at the moment when the high-speed rotating shaft 33 is connected to the sealing part 60 where the vacuum chamber body 12 is connected, and the plasma arc 27 flame melts the surface of the master alloy ingot 30 ( 26 are isolated from the vacuum chamber 14 through the flange-type powder collecting tube 15 and collected in the powder collecting unit 16.

Next, the method of manufacturing soft magnetic powder using the manufacturing apparatus of the soft magnetic powder of this invention comprised as mentioned above is demonstrated.

The present invention is to prepare a soft magnetic metal powder of iron (Fe), cobalt (Co), nickel (Ni) and various metal alloy composition into a spherical soft magnetic powder by the plasma arc rotary electrode rapid cooling method Method.)

First, the soft magnetic master alloy ingot 30 is prepared in advance in an induction melting furnace and mounted in the ingot holder 32 fixed in the vacuum chamber 14. In the plasma electrode (cathode: cathode) 20 in which the ingot holder 32 in which the master alloy ingot 30 is held is gradually increased to a desired rotational speed and installed to face the master alloy ingot (anode) 30. Generates an arc, forms the soft magnetic powder 26 of fine grains by controlling the plasma electrode 20, and collects the soft magnetic powder 26 in the powder collecting unit 16 located under the vacuum chamber 14. The powder collecting part 16 containing the collected soft magnetic powder 26 is separated from the vacuum chamber 14.

In more detail, the powder manufacturing method of the present invention is described in detail. After the solid alloy of the master alloy or the intermetallic compound cast separately in an induction melting furnace is attached to the ingot holder 32 in the vacuum chamber body 12, the vacuum chamber 14 is attached. Continue pumping using a rotary pump or diffusion pump so that the vacuum is in the range of 10 ^-5 to 10 ^-6 Torr.

When the degree of vacuum reaches a desired range, argon gas is reversely injected through the gas inlet 82 to fill the vacuum to 0.3 to 0.6 atm.

Then, the DC motor 42 which drives the rotation of the high speed rotation shaft 33 is operated in the instrument panel provided separately. Initially, the rotation speed is maintained at a low speed of 100 to 200 rpm for several tens of seconds, and then the rotation speed is increased to 3,000 to 4,000 rpm in one to two minutes.

6 is an explanatory diagram for explaining the interaction between the plasma arc (negative electrode) and the ingot (positive electrode) used in the present invention.

When the control switch (not shown) provided on the pressure gauge 87 side is operated, the electrode 20 generating the plasma arc gradually approaches the end 22 of the master alloy ingot 30. When the high frequency induction current switch is operated at a position where two pole distances are 3 to 5 mm, argon plasma arc is generated at the electrode 20. At this time, the secondary input current is set to 100 to 150 amps supplied from the DC power supply 50 having a capacity of 50 to 60 kw. When the arc occurs, the secondary input current of the DC power supply 50 is gradually increased to control the intensity of plasma energy by adjusting the electrode 20, which is the tungsten cathode, by 30 to 50 mm or more, and then 200 to 1500 amp. The current condition is set in the range, and the secondary input voltage at this time is set in the range of 40 to 60 volts by itself.

When the overall working conditions are determined, the ingot material is uniformly dissolved in the anode radius range of the ingot 30 facing and moving the plasma arc electrode 20 back and forth by the control switch provided in the pressure gauge 87 separately. In this pre-process proceeds, the interval of the electrode 20 is continuously adjusted.

When the plasma arc contacts the surface of the master alloy ingot 30, the dissolved solution flows to the edge of the ingot once by centrifugal force to form a mound. The mound of this solution is maintained by surface tension until then. However, the feed field is centrifugal force surpasses the surface tension, and the solution will come out from the surface of the ingot 30.

For reference, the centrifugal force acting on the dissolved ingot 30 can be expressed as follows.

Centrifugal force = (πd ³ ρ / 6). (ΩD / 2)

Surface tension ∝γd

Where d is the particle size of the powder formed, ρ is the density of the dissolved alloy, ω is the angular velocity (rotational speed) of the ingot, D is the diameter of the ingot used, and γ is the surface tension of the dissolved alloy.

Therefore, the particle size of the powder formed when the centrifugal force and the surface tension are set equally is as follows.

In reality, however, the powder is not formed with the same particle size but is formed with a certain distribution, so that the average particle size (d _a ) is used by introducing the dissolution rate (Q) of the ingot. Therefore, the average particle size of the powder is determined by (1) the diameter of the used ingot, (2) the properties of the material used, that is, the surface energy and density, and (3) the strength of the plasma arc used.

(Where ω is the ingot's angular velocity, D is the ingot's diameter, γ is the surface tension of the molten alloy, and ρ is the density of the molten alloy)

In the above formula, the unit of d _u is μm, D is m, ρ is kg / m ³ , ω is rad / sec, γ N / m, and Q is m ³ / sec.

In addition, the present invention by the oil supply pump 80 a certain amount of lubricating oil from the outside of the vacuum chamber 14 to the large bearing 72 of the high speed rotation shaft 33 for smooth rotational movement of the ingot holder 32 that rotates at high speed. And driving an external rotary motor 42 and a pulley to adjust the high speed rotation shaft 33 connected to the ingot holder 32 at an arbitrary rotation speed.

In the method for producing a soft magnetic powder of the present invention, in the above method, an appropriate rotational speed of the master alloy ingot 30 is selected, and the diameter of the ingot (or ingot holder) to be used initially is appropriately selected, or the surface of the ingot 30 is selected. The conditions for generating the plasma arc to be dissolved instantaneously, that is, the proper selection of the current and the voltage are very important, and the distance between the surface of the ingot 30 and the plasma generating electrode 20 must be appropriately determined. For example, the master alloy ingot 30 uses a round rod shape having a diameter of 50 to 100 mm, and the length of the ingot 30 of the portion to be fitted to the ingot holder 32 is 150 to 250 mm.

More precisely, the diameter of the ingot 30 is determined according to the desired powder particle size. In order to obtain a powder having a particle size of 50 to 200 µm, an ingot 30 having a diameter of 100 to 200 mm and a length of 200 to 600 mm is used.

In a more preferred embodiment of the present invention, in order to exclude the possibility of the presence of oxygen in the vacuum chamber 14, argon gas or the like, which is inert gas, is injected through a gas injection pipe as follows.

First, the vacuum degree in the vacuum chamber is maintained at 10 ^-5 to 10 ^-6 Torr, and then argon inert gas (in some cases nitrogen) is injected to maintain the vacuum degree in the vacuum chamber 14 at 0.3 to 0.6 atm.

The initial power for generating the plasma arc uses a DC generator of 30 to 60 kw, and the plasma arc generating condition used here is a secondary DC current of 200 to 1500 amps and a secondary DC voltage of 40 to 70 volts. Increase the rotation speed of the ingot. The rotational speed of the initial ingot 30, which is the step of generating plasma, is set in the range of 4,000 to 6,000 rpm, and in the step of producing the actual powder, it is set in the range of 7,000 to 10,000 rpm.

In addition, the particle size is also determined by the rotational speed of the ingot 30, and the energy of the arc is determined according to the current / voltage condition of the plasma, which is also a decisive factor in the powder particle size.

More preferably, the distance between the surface of the ingot 30 and the plasma arc electrode 20 flows a current / voltage while maintaining an interval of about 30 to 60 mm.

Hereinafter, each embodiment of the present invention will be described in detail.

Example 1

The 3wt% Si, 5wt% Si, and 6.5wt% Si master alloy ingots 30, which have excellent magnetic properties (especially super-permeability), are melted in an induction furnace in advance and machined. The final size was 75 mm in diameter and 250 mm in length.

After the master alloy ingot 30 was correctly attached to the ingot holder 32 in the vacuum chamber 14, the rotary pump or the diffusion pump was operated to proceed until the vacuum chamber vacuum degree reached 2.5 × 10 ⁻⁶ Torr. Thereafter, argon gas was reversely injected through a gas suction port (not shown) provided in the vacuum chamber main body 12, and the pressure gauge 87 attached to the vacuum chamber main body 12 showed 0.5 atm.

Then, by slowly rotating the ingot 30 while operating the rotation speed switch of the throttle plate to be 4,000 rpm for 2 minutes, and immediately operating the 60 kw DC power supply 50 connected to the manufacturing apparatus (of course The initial secondary input current was set to 150 amps (using a switch on the throttle), at which point the input voltage was 50 volts.

After setting the gap between the plasma arc generating electrode 20 and the surface of the ingot 30 to 3 mm, a weak arc was generated once by operating a switch of the high frequency induction apparatus.

Subsequently, the ingot rotation speed was increased to 7,500 rpm in 2 minutes, and the secondary input current was increased to 300 amp., And the distance between the plasma arc generating electrode 20 and the rotating ingot 30 was increased to 40 mm. .

Under these conditions, the powder manufacturing process was performed for 20 minutes, and the input power was stopped to complete the process. The Fe- (3-6.5) wt% Si powder thus prepared was collected and the distribution of the particle size was measured.

Table 1 shows the results corresponding to Example 1.

As shown in Table 1, the Fe-Si alloy has a decrease in the surface energy of the Fe-Si alloy solution as the Si content is increased, so that the resulting powder has a wider distribution toward the smaller particle size when the Si-rich alloy is used. It can be seen that it is obtained.

Example 2

The mother alloy was prepared in the same manner as in Example 1 and the vacuum degree was adjusted. However, the alloy used in this Example 2 is a Fe-Ni-based soft magnetic alloy was selected from three compositions, such as 40wt.% Ni, 50wt.% Ni and 80wt.% Ni.

The same procedure and procedure as in Example 1 were followed to generate a plasma arc and rotate the ingot to set final powder manufacturing conditions. However, this time, the ingot rotation speed used to check the effect of the dissolution rate of the master alloy on the powder particle size was divided into 6,000, 7,000 and 8,500 rpm, and the manufacturing time was set to 20 minutes as in Example 1 at each rotation speed. After that, all processes were stopped.

The powder thus obtained was collected and analyzed for particle size distribution in the same manner as in Example 1. Table 2 summarizes the results obtained in Example 2.

As can be seen in Table 2, the particle size of the powder tends to be widely distributed toward the fine side as the ingot rotates from 6,000 rpm to 8,000 rpm in the same composition. In addition, as the content of Ni increases with the rotational speed of the same ingot, the particle size tends to be coarse. This is because the surface energy of the alloy solution increases as the content of Ni increases in the Fe-Ni alloy. .

Therefore, according to the apparatus for producing a soft magnetic powder of the present invention, and a method for producing the soft magnetic powder and the soft magnetic powder produced by the method, the powder having excellent soft magnetic properties can be obtained even with a soft magnetic material having an alloy or an intermetallic compound composition of any composition. It can be produced and works well because the inert gas is not supplied continuously to generate plasma arc in the process of working, but it is supplied once, and the workability is good, and the consumption of raw materials is consumed because the non-consumable tungsten electrode is used. Less, even in a high vacuum atmosphere can be rotated at high speed alloy ingots of the anode without loss of rotational force has the effect of maximizing productivity.

Claims (16)

A vacuum chamber body 12 having a wall of a circular cross section, a vacuum chamber 14 formed by the vacuum chamber body 12, and an electrode 20 movably installed in the vacuum chamber 14 to generate a plasma arc. And a master alloy ingot 30 rotatably mounted on a center line of the electrode 20, a high speed rotating shaft 33 for rotating the master alloy ingot 30, and the vacuum chamber body 12. Inert gas is supplied through the sealing unit 60 in the vacuum chamber 14 while supplying a lubricating oil to the sealing unit 60 and the sealing unit 60 to maintain rotational tightness between the high speed rotation shafts 33. Apparatus for producing soft magnetic powder, characterized in that it is composed of an oil supply pump (80) for supplying, and a powder collecting part (16) installed in the lower part of the vacuum chamber body (12) to collect powder. The apparatus of claim 1, wherein the vacuum chamber (14) and the powder collecting part (16) collect powder produced by being connected to each other through a flange-type powder collecting pipe (15). The inductively mounted electrode 20 has a linear movement distance of at most 200 mm, and a range of left and right linear movements is 50 to 70 mm corresponding to a radial distance of a master alloy ingot diameter. Apparatus for producing soft magnetic powder. The soft magnetic material according to claim 1, wherein the master alloy ingot 30 provided on the centerline of the electrode 20 is fixed by an ingot holder 32 of a chuck fixing method. Apparatus for manufacturing powder. The rear end space of claim 1, wherein the sealing part 60 comprises an oil suction port 67 through which lubricating oil is sucked, a rotary sealing part 63 serving as a front half space, a SiN gasket 64, and a graphite gasket 65. Floating seat 68, at least five O-rings 70 for airtightness, and a large bearing 72 bearing the high-speed rotation shaft 33 of the soft magnetic powder, characterized in that Manufacturing equipment. The soft magnetic property according to claim 1 or 5, wherein the supply of lubricating oil required for the rotation of the master alloy ingot (30) is supplied from an oil supply pump (80) connected to the sealing portion (60). Apparatus for manufacturing powder. The oil supply pump (80) of claim 6, wherein the oil supply pump (80) includes an oil storage chamber (83) for storing oil, a gas inlet (82) for supplying an inert gas into the vacuum chamber (14), and the oil storage chamber (83). An apparatus for producing soft magnetic powder, comprising an oil exhaust port (85) for supplying oil from) and using oil of silicone system. According to claim 7, The oil reservoir 83 has a spring valve 84 for the automatic supply of oil, the ball valve 86 and the pressure gauge 87 for pressure regulation and detection is installed, the oil Apparatus for producing a soft magnetic powder, characterized in that it comprises a level gauge (89) for sensing the water level. The level gauge (89) for detecting the oil level is provided with an inlet (90), an outlet (92) and an outlet (92) for injecting / discharging the sealant. Apparatus for producing magnetic powder. The apparatus of claim 5, wherein the large bearing (72) is installed on the sealing part (60) and the high speed rotation shaft (33) by a plurality of fixing pins (74). Ingot 30 of any one of the soft magnetic alloys selected from the group consisting of iron (Fe), cobalt (Co), and nickel (Ni) alloys is manufactured in a predetermined shape in an induction furnace, and is connected to the vacuum chamber 14. Inserting into an ingot holder 32 provided at the end of the high speed rotary shaft 33, performing a vacuum in the vacuum chamber 14 to 10 ^-5 to 10 ^-6 Torr vacuum degree, and argon gas in the vacuum chamber 14; Back-injecting to maintain the pressure inside the vacuum chamber 14 at 0.3 to 0.6 atm, and gradually rotating the ingot 30 and external to the plasma arc generating electrode 20 facing the ingot 30. Generating an argon plasma by loading a 40-60 kW class DC power source connected to the ingot; and rotating the ingot while controlling the intensity of the generated argon plasma arc through a secondary input current and voltage of 200 to 1500 amps and 40 to 60 V. Genus 30 The initial rotational speed is increased from 4,000 to 6,000 rpm to a high speed in the range of 7,000 to 10,000 rpm, and controlling the distance between the electrode 20 and the ingot 30 to artificially form the particle size of the soft magnetic powder. Method for producing a soft magnetic powder, characterized in that. 12. The method of claim 11, wherein the rotation speed of the ingot is controlled by a rotation drive motor for 10,000 rpm. The method for producing a soft magnetic powder according to claim 11, wherein the ingot (30) uses a diameter of 100 to 200 mm phi and a length of 200 to 600 mm. 12. The method of claim 11, wherein the electrode (20) satisfies the following operating range. Back and forth movement distance = up to 200mm, Up and down movement distance = up to 70mm, Left and right moving distance = up to 34 mm. 12. The method of claim 11, wherein the soft magnetic powder has an average particle size of 50 to 200 µm. 16. The method of claim 15, wherein the average particle size of the soft magnetic powder is obtained by the following equation. Where ω is the ingot's angular velocity, D is the ingot's diameter, γ is the surface tension of the molten alloy, and ρ is the density of the molten alloy.