JP3262669B2 - Soft magnetic alloy powder, method for producing the same and soft magnetic alloy compact - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soft magnetic alloy compact used for a core of a magnetic head, a magnetic core of a pulse motor, a magnetic core of a choke coil, and the like, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, demands for smaller and lighter electronic devices and higher performance have been further increased, and in order to satisfy such demands, the driving frequency of inductors such as power transformers has been further increased. . To cope with these problems, a magnetic material having higher specific resistance is required in addition to the conventional soft magnetic characteristics. In particular, in the case of pulse motors, transformers, choke coils, etc., ferrite is often used, but this has a small magnetization,
In order to cope with miniaturization and higher frequency, a material having more excellent magnetic properties is desired.

[0003]

Therefore, the inventors of the present invention have found that an Fe-Hf-O-based alloy or an Fe-Ta-O-based alloy in which Fe-based crystals and Hf or Ta amorphous are mixed is highly intrinsic. It has been found that it has resistance and excellent magnetic properties. However, these soft magnetic alloys are obtained by the sputtering method, and when manufactured, they are in the form of thin films.Therefore, in order to use them as cores for magnetic heads or magnetic cores for pulse motors, processing is required. There is a difficult problem.

Accordingly, the present inventors have considered the application of such soft magnetic alloys having excellent magnetic properties to the core of a magnetic head, the magnetic core of a pulse motor, or the core of a transformer, and have the excellent soft magnetic properties. An attempt was made to form the alloy powder into a desired shape by producing the alloy powder and then press molding, and the present invention was achieved.

The present invention has been made in view of the above circumstances, and is directed to a soft magnetic alloy powder having both excellent soft magnetic characteristics and a high saturation magnetic flux density, a method for producing the same, and a bulk magnetic material comprising the soft magnetic alloy powder. It is an object to provide a soft magnetic alloy compact.

[0006]

The soft magnetic alloy powder of the present invention comprises Fe and at least one element selected from the group consisting of Hf and Ta.
And containing consists of a O, and an amorphous phase mainly composed of oxides of the selected metals and is characterized by comprising a mixed phase of a crystal phase of BccFe.

Further, the composition formula is represented by Fe _a M _b O _c , wherein M is at least one of Hf and Ta.
A is 20 or more and 85 or less, b is 5 or more and 30 or less, and c is 15 or more and 55 or less.

In particular, it is preferable that M is Hf, a is 50 or more and 75 or less, b is 8 or more and 16 or less, and c is 16 or more and 34 or less.

Alternatively, it is preferable that M is Ta, a is 35 or more and 80 or less, b is 5 or more and 20 or less, and c is 15 or more and 46 or less.

The method for producing a soft magnetic alloy powder according to the present invention
e, and powder of an oxide of at least one element of Hf or Ta is mixed, pulverized, and stirred to produce a powder having a compositional formula represented by the following formula. Fe _a M _b O _c where M is at least one element of Hf or Ta , a is 20 or more and 85 or less, b is 5 or more and 3 or more.
0 or less, c is 15 or more and 55 or less.

Alternatively, Hf or Ta may be added to Fe powder .
A method for producing a soft magnetic alloy powder, comprising mixing powder of at least one element in an oxygen gas atmosphere, pulverizing, and stirring to produce a powder having a composition formula represented by the following formula. Fe _a M _b O _c where M is at least one element of Hf or Ta , a is 20 or more and 85 or less, b is 5 or more and 3 or more.
0 or less, c is 15 or more and 55 or less.

In this case, it is preferable to use a planetary ball mill for stirring.

The Fe powder is 70-95%, Hf
Alternatively, it is preferable to mix such that the powder of the oxide of at least one element of Ta is 5 to 30%.

Alternatively, 70 to 95% of Fe powder, Hf
Or 5 to 3 powders of at least one element of Ta
It is preferable to mix so as to be 0%.

[0015]

The soft magnetic alloy compact of the present invention has a composition formula:
Fe _a M _b O _c , where M is Hf or Ta
A is at least 20 and 8
5 or less, b is 5 or more and 30 or less, c is 15 or more and 5 or less
It is characterized in that 5 or less powders are formed by pressure molding.

In this case , it is preferable that a is 35 or more and 80 or less, b is 5 or more and 20 or less, and c is 15 or more and 46 or less.

[0018]

The soft magnetic alloy powder according to the present invention has a composition of Fe _a M _b
It is represented by O _c . In the soft magnetic alloy according to the present invention, Fe is a main component and is an element responsible for magnetism. In order to obtain a high saturation magnetic flux density, the content of Fe is preferably as large as possible. However, when the content is 85 atomic% or more, the specific resistance decreases. On the other hand, when Fe is less than the range of the present invention, the specific resistance can be increased, but the saturation magnetic flux density decreases.

The element represented by M is a rare earth element (ie, Sc, Y, or L belonging to Group 3A of the periodic table).
a, Ce, Pr, Nd, Pm, Sm, Eu, Gd, T
lanthanoids such as d, Dy, Ho, Er, Tm, Yb, and Lu), Ti, Zr, Hf, V, Nb, Ta, W, and other elements of the 4A, 5A, and 6A groups of the periodic table. At least one element or a mixture thereof. The element represented by M is necessary for obtaining soft magnetic characteristics. These are easily bonded to oxygen, and form an oxide by bonding. The specific resistance can be increased by adjusting the content of the oxide. Among them, Hf or Ta is suitable as the soft magnetic alloy powder. When M is Hf, the composition formula Fe _a Hf _b O _c
Where 50 ≦ a ≦ 75, 8 ≦ b ≦ 16, 16 ≦ c
It is more preferable that ≦ 34. Moreover, when M is Ta, the compositional formula _{Fe a Ta b O c, 35} ≦ a
More preferably, ≦ 80, 5 ≦ b ≦ 20, and 15 ≦ c ≦ 46.

The soft magnetic alloy powder of the present invention is manufactured by using a mechanical alloying method in which a powder of Fe and a powder of the metal or metal oxide represented by M are mixed, pulverized and stirred. According to this method, a large amount of alloy powder can be produced very easily at a time. The soft magnetic alloy powder of the present invention is used as a compact having a shape suitable for each application through processing such as plasma sintering, extrusion molding, and hot pressing.

[0021]

EXAMPLE An example of a method for producing a soft magnetic alloy powder of the present invention will be described below. First, each raw material is weighed so as to have a composition of the soft magnetic alloy powder according to the present invention. At this time, the iron powder has a particle size of 1
It is preferable that the HfO ₂ powder or the Ta ₂ O ₃ powder has a particle diameter of 2 μm or less. Next, these are enclosed in a stainless steel (SUS304) pot (with a capacity of 170 ml) together with stainless balls (diameter 4 mm) of the same material as the pot. The total volume of the stainless steel balls was 30% (volume ratio) of the inner volume of the pot.

Then, using a high energy type planetary ball mill, pulverization and mixing are performed at a centrifugal acceleration of about 100 G for a predetermined time. Thus, the Fe—Hf—O-based alloy or Fe
-A Ta-O alloy was obtained. For the pulverization, a pulverization machine such as a rotor speed mill may be used in addition to a planetary ball mill. Further, in the above method, iron powder and HfO ₂
Although the mixing or pulverization of the powder or Ta ₂ O ₃ powder is performed in an O ₂ atmosphere, the amount of oxygen in the material can be adjusted by performing the mixing or pulverization in an inert gas such as Ar gas.
The soft magnetic alloy powder of the present invention can also be manufactured by mixing and pulverizing a predetermined amount of iron powder and Hf powder or Ta powder. In this case, it is necessary to perform mixing and pulverization in an oxygen gas atmosphere. By performing the treatment in an oxygen gas atmosphere, Fe—Hf—O or Fe—Ta—O becomes an oxide to produce a soft magnetic alloy powder. in this case,
Oxygen gas needs to be at least 20% in the atmosphere.

Fe and HfO ₂ were mixed at a mixing ratio of 78:22, and the pulverization times of the alloy powders produced as described above were 0 (g) and 1800, respectively.
(F), 3600 (e), 9000 (d), 18000
An X-ray diffraction test was performed on the seven alloy powders at (c), 28800 (b) and 36000 (a) seconds. The test results are shown in FIG. Also, the results (h) of the X-ray diffraction test of the alloy film of Fe _54.9 Hf ₁₁ O _34.1 are shown in FIG. This Fe _54.9 Hf
_{The 11} O _34.1 alloy film has a mixture of Fe-based crystals and amorphous,
High saturation magnetic flux density Bs (1.26 (T)), low coercive force Hc (0.78 (Oe)), high magnetic permeability μ (2199
(10 MHz)), which is an alloy film having excellent soft magnetic properties. Therefore, this Fe _54.9 Hf ₁₁
An alloy powder exhibiting an X-ray diffraction pattern similar to the X-ray diffraction pattern of the O _34.1 alloy film is composed of bccFe crystal phase and Hf
It is understood that an amorphous phase of O was generated, and the powder was a soft magnetic alloy powder having excellent soft magnetic properties.

FIG. 1 shows that when the pulverization time is longer than 18000 seconds ((c), (b), (a)), the intensity of the diffraction line is reduced, but (111), (200) of HfO ₂ is obtained.
Diffraction lines on the surface and diffraction lines belonging to bccFe appear. When further pulverization is performed, the intensity of these diffraction lines gradually decreases. In the pulverization for 28,800 seconds, a halo peak indicating an amorphous state near 2θ = 40 ° and a (110)
Only broad peaks that are considered to be attributed to are observed. Such a diffraction pattern is the same as the diffraction pattern (h) of the Fe—Hf—O film showing high resistance and excellent soft magnetic properties, and thus has the same structure as the Fe—Hf—O film by pulverization. It is considered that a powder was obtained.

Similarly, when the powder of Fe ₉₀ (Ta ₂ O ₅ ) ₁₀ is pulverized, the Fe-Hf
It showed an X-ray diffraction pattern similar to that of the -O film. Therefore,
_{Fe9 0 (Ta 2 O 5)} 10 , is considered to shift to mixed phase of Fe-Hf-O film similar amorphous phase and bcc phase by milling. However, the milling time is 7200
It is desired that the time be 0 second or less. If the length is too long, a material such as a ball mill may be mixed (for example, Cr, Ni, or the like).

In producing the Fe—Hf—O alloy powder, the mixing ratio of the Fe powder and the HfO ₂ powder is changed.
After pulverization (pulverization time was 18000 seconds), an X-ray diffraction test of each obtained alloy powder was measured in the same manner as described above. FIG. 2 shows the measurement results. The mixing ratios of the added Fe powder and HfO ₂ powder were seven as shown in Table 1.

[0027]

[Table 1]

From FIG. 2, it can be seen that only those having a compounding ratio of Fe powder and HfO ₂ powder of 90:10 (k) or 78:22 (l) have bccFe crystals and HfO amorphous phase in part A. Is shown.

The same measurement was performed on the Fe-Ta-O-based alloy powder. Table 2 shows the mixing ratio of the added Fe powder and Ta ₂ O ₅ powder. The measurement results are shown in FIG.

[0030]

[Table 2]

From FIG. 3, it is found that only those having a mixing ratio of Fe powder and Ta ₂ O ₅ powder of 90:10 (q) or 80:20 (r) have bccFe crystals and Ta ₂ O ₅ An X-ray diffraction pattern showing the amorphous phase of is shown.

Further, the alloy powder of this embodiment is extruded by an extruder 1 as shown in FIG. The extrusion device 1 of this example includes a cylindrical container 2,
A die 3 is provided at the outlet of the container 2 and a die holder 4 for holding the die 3. The billet 6 can be pushed into the inside of the container 2 by a push rod 5. The billet 6 can be extruded through 3 to form an extruded billet 6 ′, and the powder contained in the billet 6 can be extruded. As shown in FIG. 5, for example, the billet 6 has a core 11 provided inside a cylindrical case 10 having a closed end, and the powder 1 to be compacted inside the case 10.
2, and the rear end of the case 10 is closed by an inner cap 13 and an outer cap 14. Here, molding can be performed without using the core 11 in particular, but it is desirable to use the core 11 in order to obtain a good extruded material.

When extrusion is performed using the extrusion apparatus 1 shown in FIG. 4, the temperature of the container 2 is adjusted so that the extrusion temperature is slightly lower than the crystallization temperature of the alloy of each of the above-mentioned compositions. Is preferred. Specifically, 300-
A range of 600 ° C. is preferred. By extruding at a temperature near this softening point, it is possible to smoothly extrude the alloy powder. The extrusion pressure is 500-1300MPa.
It is preferable that If the pressure is less than 495 MPa, molding is difficult, and if the pressure is more than 1,300 MPa, the molding machine is overloaded.

As means for compacting the alloy powder, H
Although an IP (hot isostatic pressing) method is also conceivable, this method generally requires processing at a high temperature of 800 ° C. or higher.
When a fine crystalline phase is precipitated inside the amorphous phase, the crystal grain size becomes coarse, and the magnetic properties may be degraded. Therefore, extrusion molding is more preferable as the means for consolidation.

When the extrusion is completed, the compact is taken out of the billet 6 and subjected to a heat treatment. The compact immediately after the extrusion process is in a mixed phase in which an amorphous phase is a main component and a fine crystalline phase having a bcc structure is partially deposited therein.

The alloy powder of this embodiment is, for example, as shown in FIG.
Is sintered by a discharge plasma sintering apparatus 44 as shown in FIG. In the discharge plasma apparatus of this example, a mold composed of a sintering die 46, an upper punch 48, and a lower punch 50 is used to form an upper punch electrode 54 in a water-cooled vacuum chamber 52.
The lower punch electrode 56 and the upper punch electrode 54 are provided with a DC pulse power supply device 58 and a pressurizing mechanism device 60 for supplying current to the upper punch electrode 54 and the lower punch electrode 56. When producing a sintered body using the discharge plasma sintering apparatus 44 shown in FIG. 9, the powder material 62 of the present invention is placed in a mold composed of the sintering die 46, the upper punch 48, and the lower punch 50. And a DC pulse power is supplied to the powder material 62 by the DC pulse power supply 58 through the upper punch electrode 54 and the lower punch electrode 56. As a result, discharge occurs on the powder surface. At the same time, the powder material 62 is pressed by the pressing mechanism device 60 through the upper punch electrode 54 and the lower punch electrode 56. Sintering is performed using Joule heat generated by energization and plastic flow of material due to pressure. Specifically, it is preferable that the energizing current is an energizing amount capable of maintaining a temperature range in which the powder material 62 becomes 300 to 650 ° C. Further, the pressing force is preferably set to 350 MPa to 1000 MPa. If the pressure is less than 300 MPa, molding is difficult, and if a pressure exceeding 1000 MPa is applied, the molding machine is overloaded.

The compact produced as described above has excellent saturation magnetic flux density, high magnetic permeability, and low coercive force. Therefore, this compacted body is used as a core of a magnetic head or a core of a transformer, and further,
It can be widely applied as a magnetic component such as a magnetic needle of a pulse motor, and a magnetic component having characteristics superior to those of a conventional material can be obtained.

An example in which a choke coil is manufactured using the soft magnetic alloy powder of the present invention will be described. The choke coil is as shown in FIG. 6, and includes a magnetic core 18 formed by combining two substantially U-shaped soft magnetic bodies 16, 16, and a winding 2.
0 is wound and a bobbin 22 mounted on the magnetic core 18. Such a magnetic core 18 can be manufactured by performing the above-described pressure molding on a soft magnetic alloy powder. With the choke coil having the magnetic core 18 made of the soft magnetic alloy powder of the present invention, it is possible to reduce the size and increase the frequency.

An example of producing a saturable reactor using the soft magnetic alloy powder of the present invention will be described. The saturable reactor constitutes a magnetic switch for a pulse generator for supplying a high-voltage rectangular wave pulse to an electron gun, a klystron, or the like, and is schematically as shown in FIG. FIG.
In the saturable reactor 24 shown in FIG. 1, a main winding 28 is wound around a magnetic core 26 made of a soft magnetic material, and ends of the main winding 28 are connected to connection terminals 30 and 32.
Has a configuration in which a reset winding 34 is wound. Also in the saturable reactor 24, if the magnetic core 26 is formed by compacting the soft magnetic alloy powder of the present invention, the size and the frequency can be reduced.

Next, an example in which the soft magnetic alloy powder of the present invention is applied to a vehicle-mounted antenna will be described. In recent vehicles such as trains and automobiles, various types of information are transmitted and received from outside the vehicles. For example, if it is a train, speed control, stop control, etc.
In the case of a car, in addition to the radio, current location data, a destination guidance system, and the like are transmitted and received during traveling. To transmit and receive such information, it is necessary to provide an antenna in the vehicle. However, in the case of a conventional in-vehicle antenna, the transmission / reception level is low, so that the in-vehicle antenna has been increased in size. However, this is unsuitable especially for use in vehicles, and there has been a strong demand for miniaturization. According to the present invention, by using a soft magnetic alloy powder having excellent magnetic properties for the core of an in-vehicle antenna, the transmission / reception level can be improved, and the in-vehicle antenna can be downsized. That is, in the example of the on-vehicle antenna shown in FIG. 8, the on-vehicle antenna 36 includes a transmitter (receiver) and a bulk antenna core 38 formed by pressing the soft magnetic alloy powder of the present invention.
It is schematically configured by winding a coil 42 connected to 40.

[0041]

The soft magnetic alloy powder of the present invention comprises Fe, H
At least one element of f or Ta and O, and a mixed phase of an amorphous phase mainly composed of the selected metal oxide and a crystal phase of bccFe. is there.

Further, the composition formula is represented by Fe _a M _b O _c , wherein M represents at least one element of Hf or Ta or a mixture thereof, and a is 20 or more and 85 or more.
Hereinafter, b is 5 or more and 30 or less, c is 15 or more and 55 or less.
These are:

This soft magnetic alloy powder is composed of Fe powder and H
It is manufactured by mixing an oxide powder of at least one element of f or Ta or these elements in an oxygen gas atmosphere, and pulverizing and stirring for a predetermined time.

The soft magnetic alloy powder produced by the method of the present invention is further compacted to form a compact having a shape suitable for various uses.

The soft magnetic alloy powder of the present invention exhibits excellent soft magnetic properties, and various magnetic parts composed of a compact made of this powder also have improved magnetic properties. Therefore, even a magnetic component other than a thin film-shaped one can exhibit magnetic properties that have not existed before .

[Brief description of the drawings]

FIG. 1 is a diagram showing the results of an X-ray diffraction test of an alloy powder at each grinding time.

FIG. 2 is a view showing the results of an X-ray diffraction test of alloy powders for different mixing ratios of Fe and HfO ₂ .

FIG. 3 is a diagram showing the results of an X-ray diffraction test of alloy powders for different mixing ratios of Fe and Ta ₂ O ₅ .

FIG. 4 is a cross-sectional view illustrating an example of an extruder used in the present embodiment.

FIG. 5 is a sectional view of a billet used in the extrusion apparatus shown in FIG.

FIG. 6 is a perspective view of the choke coil of the present embodiment.

FIG. 7 is a perspective view of the saturable reactor of the present embodiment.

FIG. 8 is a schematic configuration diagram of a vehicle-mounted antenna according to the present embodiment.

FIG. 9 is a schematic configuration diagram of a spark plasma sintering apparatus.

[Explanation of symbols]

 1 Extrusion Device 18 Magnetic Core 24 Saturable Reactor 26 Magnetic Core 36 In-Vehicle Antenna 38 Antenna Core

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ identification code FI H01F 1/20 H01F 1/20 (58) Fields investigated (Int.Cl. ⁷ , DB name) B22F 1/00 B22F 9/04 C22C 33/02 C22C 38/00 C22C 45/02 H01F 1/20

Claims (11)

(57) [Claims] 1. Fe and at least one of Hf and Ta
A soft magnetic alloy powder comprising a kind of element and O, and a mixed phase of an amorphous phase mainly composed of the oxide of the selected metal and a crystalline phase of bccFe. 2. The composition formula is represented by Fe _a M _b O _c , wherein M represents at least one element of Hf or Ta , a is 20 or more and 85 or less, b is 5 or more and 30 or less.
Hereinafter, c is 15 or more and 55 or less. 3. The soft magnetic alloy powder according to claim 2, wherein M is Hf, a is 50 or more and 75 or less, and b is 8 or more.
A soft magnetic alloy powder characterized by being not less than 16 and not more than 16, and c is not less than 16 and not more than 34. 4. The soft magnetic alloy powder according to claim 2, wherein M is Ta, a is 35 or more and 80 or less, and b is 5 or more.
A soft magnetic alloy powder characterized by being not less than 20 and not more than 20 and c is not less than 15 and not more than 46. 5. A powder of Fe and a powder of an oxide of at least one element of Hf or Ta are mixed, pulverized and stirred to obtain a powder having a composition represented by the following formula: A method for producing a soft magnetic alloy powder, characterized by being produced. Fe _a M _b O _c where M is at least one element of Hf or Ta , a is 20 or more and 85 or less, b is 5 or more and 3 or more.
0 or less, c is 15 or more and 55 or less. 6. A powder of Fe and a powder of at least one element of Hf or Ta are mixed in an oxygen gas atmosphere, pulverized and stirred, and a powder having a composition represented by the following formula: And a method for producing a soft magnetic alloy powder. Fe _a M _b O _c where M is at least one element of Hf or Ta , a is 20 or more and 85 or less, b is 5 or more and 3 or more.
0 or less, c is 15 or more and 55 or less. 7. The method for producing a soft magnetic alloy powder according to claim 5, wherein a planetary ball mill is used for stirring. 8. A powder of 70 to 95% of Fe, Hf or
The powder of the oxide of at least one element of Ta is 5 to 5.
6. The mixture according to claim 5, wherein the content is 30%.
A method for producing the soft magnetic alloy powder described above. 9. A powder of 70 to 95% of Fe, Hf or
The method for producing a soft magnetic alloy powder according to claim 6, wherein the powder of at least one element of Ta is mixed so as to be 5 to 30%. 10. The composition formula is represented by Fe _{a Mb} O _c ,
Here, M is at least one element of Hf or Ta , a is 20 or more and 85 or less, b is 5 or more and 3 or more.
0 or less, c is 15 or more and 55 or less powder compacted, The soft magnetic alloy compact characterized by the above-mentioned. 11. The soft magnetic alloy compact according to claim 10 , wherein a is 35 or more and 80 or less, and b is 5 or more and 2 or less.
0 or less, c is 15 or more and 46 or less powder compacted, The soft magnetic alloy compact characterized by the above-mentioned.