JP2001267115A - Dust core and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dust core which is low in coercive force and core loss and a method of manufacturing the same. SOLUTION: Metal glass alloy whose main phase is amorphous includes Fe, Ga and one or more elements Q selected out of P, C, Si, and B, a temperature gap ΔTx of the supercooled liquid of the metal glass alloy is 20K or above, where ΔTx is represented by a formula, ΔTx=Tx-Tg (wherein, Tx denotes a crystallization starting temperature, and Tg indicates a glass transition temperature), and the powder of the above metal glass alloy and insulating material are mixed together and molded into a dust core, and a method of manufacturing the dust core comprises a powder manufacturing process in which metal glass alloy powder is manufactured, a molding process in which the above metal glass alloy powder and insulating material are mixed together, and the mixture is compression-molded into a core precursor, and a thermal treatment in which the core precursor is thermally treated at a temperature of (Tg-170)K to (Tg)K so as to remove inner stress from it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dust core and a method of manufacturing the dust core, and more particularly to a dust core having a low coercive force and a low loss, and a method of manufacturing the same.

[0002]

2. Description of the Related Art A magnetic core used for a magnetic core component such as a transformer for a switching power supply or a smooth choke core, which requires a constant magnetic permeability up to a high frequency, is an open magnetic circuit type of ferrite, a magnetic core with a gap, or an amorphous alloy. A magnetic core in which a gap is formed in a magnetic core formed by winding a ribbon has been proposed. A dust core formed by mixing powder such as carbonyl iron, permalloy, and sendust with an insulating material has also been proposed.

[0003] However, the sintered ferrite core has a disadvantage that the core loss is small but the saturation magnetic flux density is small, and in the case of an open magnetic circuit type or a magnetic core with a gap, the leakage magnetic flux from the gap adversely affects the surrounding electric circuit. there were. Further, a dust core using powder of carbonyl iron, permalloy, sendust, or the like has a defect that the saturation magnetic flux density is superior to ferrite, but the core loss is large.

[0004]

The causes of the large core loss of the conventional dust core are that the core loss of the magnetic material used for the magnetic powder is large and that the stress applied when molding the dust core is sufficiently reduced. It was due to the inability to do so.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a dust core having low coercive force and low core loss, and a method for manufacturing the same.

[0006]

In order to achieve the above object, the present invention employs the following constitution. The powder magnetic core of the present invention has ΔT _x = T _x −T _g (where T _x is the crystallization start temperature,
T _g indicates the glass transition temperature. ), The temperature interval ΔT _x of the supercooled liquid is 20K or more, and Fe and
A powder of a metallic glass alloy containing Ga and one or more elements Q of P, C, Si, and B and having a structure having an amorphous phase as a main phase is mixed with an insulating material. It is characterized by being done. In the dust core of the present invention,
The metallic glass alloy preferably has a specific resistance of 1.5 μΩ · m or more.

It is preferable that the metallic glass alloy has the following composition. _{(Fe 1-a T a)} 100-xy Ga x Q y However, T is Co, and one or both of Ni, Q is P, C, Si, be one or more elements of B A, x, and y indicating the composition ratio are 0 ≦ a ≦ 0.15, x
≦ 20 at%, y ≦ 50 at%. The dust core of the present invention is composed of powder of the above-mentioned Fe-based metallic glass alloy (having a higher Fe content than the Co and / or Ni contents). Since the saturation magnetic flux density is higher than that of the glass alloy, it is possible to further improve the magnetic characteristics of the dust core.

[0008] In the _{(Fe 1-a T a)} 100-xy Ga x Q y a composition of the metallic glass alloy, a showing the composition ratio, x,
y is 0 ≦ a ≦ 0.15, x ≦ 20 at%, 5 at% ≦
It is more preferable that y ≦ 50 atomic%. Further, a, x, and y indicating the above composition ratios are 0 ≦ a ≦ 0.15, 0.5
It is more preferable that atomic% ≦ x ≦ 15 atomic% and 7 atomic% ≦ y ≦ 35 atomic%.

Another example of the metallic glass alloy used in the dust core of the present invention is (Fe _1-a T _a ).
A metallic glass alloy having a composition of _100-xvzw Ga _x (P _1-b Si _b ) _v C _z B _w may be used. Here, T is one or both of Co and Ni, and a, b, and
x, v, z, and w are 0 ≦ a ≦ 0.15, 0 <b ≦ 0.
8, x ≦ 20 atomic%, v ≦ 22 atomic%, 0 atomic% ≦ z ≦
10 at%, 1 at% ≦ w ≦ 20 at%. The _{(Fe 1-a T a)} 100-xvzw Ga x (P 1-b Si b) v C z B
_In a metallic glass alloy having a composition of _w , the composition ratios a, b, x, v, z, and w are 0 ≦ a ≦ 0.15, 0.
1 ≦ b ≦ 0.35, 0.5 atomic% ≦ x ≦ 15 atomic%, 7
It is more preferable that atomic% ≦ v ≦ 20 atomic%, 0 atomic% ≦ z ≦ 9.5 atomic%, and 2 atomic% ≦ w ≦ 14 atomic%. Further, a, b, x, v, z, w indicating the above composition ratio
Is 0 ≦ a ≦ 0.1, 0.1 ≦ b ≦ 0.28, 0.5 atomic% ≦ x ≦ 15 atomic%, 10 atomic% ≦ v ≦ 15.5 atomic%, 0.5 atomic% ≦ z ≦ 6 atomic%, 4 atomic% ≦ w ≦ 11
More preferably, it is atomic%.

Another example of the metallic glass alloy used in the dust core of the present invention is (Fe _1-a T _a ).
A metallic glass alloy having a composition of _100-xvzw Ga _x P _v C _z B _w may be used. Here, T is one or both of Co and Ni, and a, x, v, z, w indicating the composition ratio
Is 0 ≦ a ≦ 0.15, x ≦ 20 at%, v ≦ 22 at%, 0 at% ≦ z ≦ 10 at%, 1 at% ≦ w ≦ 20 at%. The _{(Fe 1-a T a)} 100-xvzw Ga x P v
C _z in B _w composed composition of the metallic glass alloy, a indicating the composition ratio, x, v, z, w is, 0 ≦ a ≦ 0.15,0.
5 atomic% ≦ x ≦ 15 atomic%, 7 atomic% ≦ v ≦ 20 atomic%, 0 atomic% ≦ z ≦ 9.5 atomic%, 2 atomic% ≦ w ≦ 14
More preferably, it is atomic%. Further, a, x, v, z, and w indicating the above composition ratios are 0 ≦ a ≦ 0.1, 0.5 atomic% ≦ x ≦ 15 atomic%, 10 atomic% ≦ v ≦ 15.5 atomic%, 0.5 atomic% ≦ z ≦ 6 atomic%, 4 atomic% ≦ w ≦ 11
More preferably, it is atomic%.

Examples of the insulating material include liquid or powdery organic substances such as epoxy resin, silicon resin and PVA (polyvinyl alcohol), water glass, oxide glass powder, and glassy substances produced by a sol-gel method. Alternatively, a mixture thereof can be used. Further, a stearate such as zinc stearate, calcium stearate, etc. which plays a role of a lubricant together with insulation can be used at the same time. The mixing ratio of the insulating material to be mixed is 1
A range from 5% by weight to 5% by weight is preferred. Further, the particle diameter of the metallic glass alloy powder is preferably in a range of 45 μm or more and 300 μm or less.

In the dust core of the present invention, since the powder of the metallic glass alloy having any one of the above constitutions and the insulating material are mixed and formed, the specific resistance of the whole dust core is reduced by the insulating material. As a result, the eddy current loss can be reduced, the core loss of the dust core can be reduced, and the decrease in magnetic permeability in a high frequency band can be suppressed. In the powder magnetic core of the present invention, particularly, in the case of using a metallic glass alloy having a specific resistance of 1.5 μΩ · m or more, the eddy current loss in the metallic glass alloy particles at high frequency is reduced, and the core loss is further reduced. However, it is possible to form a powder magnetic core having a low density. Further, according to the powder magnetic core of the present invention, the dust core comprises a metallic glass alloy having a temperature interval ΔT _x of the supercooled liquid, and the metallic glass alloy is heat-treated at a temperature sufficiently lower than the crystallization temperature to form the inside of the magnetic core precursor. Since the stress can be reduced or removed, a dust core having a low coercive force can be formed.

The powder magnetic core of the present invention has a coercive force of 80.
It is preferably at most A / m, more preferably at most 40 A / m.

The dust core of the present invention has a coercive force of 80 A / m or less, and is much lower than various conventionally known dust cores. In order to obtain such a low coercive force, the temperature interval of the supercooled liquid region is required as described above, and F
e, Ga, and one or more elements Q of P, C, Si, and B, and using a metallic glass alloy having a structure having an amorphous phase as a main phase. In addition to the high density, it is necessary to remove the internal stress of the dust core. Therefore, it is preferable that the dust core of the present invention has been subjected to heat treatment for removing internal stress.

Next, the method for manufacturing a dust core according to the present invention comprises a ΔT
_x = T _x −T _g (where T _x is the crystallization onset temperature and T _g is the glass transition temperature) The temperature interval ΔT _x of the supercooled liquid is 20K or more, and Fe and , Ga,
Including one or more elements Q of P, C, Si, and B;
A powder manufacturing process for manufacturing a metal glass alloy powder having a structure having an amorphous phase as a main phase, and an insulating material added to and mixed with the above metal glass alloy powder, and the mixture is compression-molded to form a magnetic core precursor. A molding step of forming a body and a heat treatment step of heat-treating the magnetic core precursor at a temperature of (T _g -170) K or more and (T _g ) K or less to remove or relax the internal stress of the magnetic core precursor. It is characterized by comprising. It is preferable that the metallic glass alloy has a specific resistance of 1.5 μΩ · m or more. In addition, it is desirable to evaporate the solvent, moisture, and the like contained in the mixture before compression molding to form an insulating material layer on the surface of the metallic glass alloy powder.

The metallic glass alloy used in the method for manufacturing a dust core of the present invention is preferably one having the following composition. _{(Fe 1-a T a)} 100-xy Ga x Q y However, T is Co, and one or both of Ni, Q is P, C, Si, be one or more elements of B A, x, and y indicating the composition ratio are 0 ≦ a ≦ 0.15, x
≦ 20 at%, y ≦ 50 at%. The above (Fe _1-a
T _a ) In a metallic glass alloy having a composition of _100-xy Ga _x Q _y, a, x, and y indicating a composition ratio are 0 ≦ a ≦ 0.15, x
It is more preferable that ≦ 20 atomic% and 5 atomic% ≦ y ≦ 50 atomic%. Further, a, x, and y indicating the above composition ratios are:
0 ≦ a ≦ 0.15, 0.5 atomic% ≦ x ≦ 15 atomic%, 7
It is more preferable that atomic% ≦ y ≦ 35 atomic%.

Another example of the metallic glass alloy used in the method for manufacturing a dust core of the present invention is (Fe
_{1-a T a) 100-} xvzw Ga x (P 1-b Si b) v may be C _z B _w becomes glassy alloy composition. Where T is C
a, b, x, v, z, and w, which are either or both of o and Ni and indicate the composition ratio, are 0 ≦ a ≦ 0.15, 0 <
b ≦ 0.8, x ≦ 20 at%, v ≦ 22 at%, 0 at% ≦ z ≦ 10 at%, 1 at% ≦ w ≦ 20 at%. The _{(Fe 1-a T a)} 100-xvzw Ga x (P 1-b S
i _{b) v} C _z in B _w composed composition of the metallic glass alloy, a showing the above composition ratio, b, x, v, z , w is, 0 ≦ a ≦ 0.
15, 0.1 ≦ b ≦ 0.35, 0.5 atomic% ≦ x ≦ 15
Atomic%, 7 atomic% ≦ v ≦ 20 atomic%, 0 atomic% ≦ z ≦
More preferably, 9.5 atomic%, 2 atomic% ≦ w ≦ 14 atomic%. Further, a, b, x,
v, z, w are 0 ≦ a ≦ 0.1, 0.1 ≦ b ≦ 0.2
8, 0.5 at% ≦ x ≦ 15 at%, 10 at% ≦ v ≦
More preferably, 15.5 atomic%, 0.5 atomic% ≦ z ≦ 6 atomic%, and 4 atomic% ≦ w ≦ 11 atomic%.

Another example of the metallic glass alloy used in the method for manufacturing a dust core of the present invention is (Fe _1-a T _a ).
A metallic glass alloy having a composition of _100-xvzw Ga _x P _v C _z B _w may be used. Here, T is one or both of Co and Ni, and a, x, v, z, w indicating the composition ratio
Is 0 ≦ a ≦ 0.15, x ≦ 20 at%, v ≦ 22 at%, 0 at% ≦ z ≦ 10 at%, 1 at% ≦ w ≦ 20 at%. The _{(Fe 1-a T a)} 100-xvzw Ga x P v
C _z in B _w composed composition of the metallic glass alloy, a indicating the composition ratio, x, v, z, w is, 0 ≦ a ≦ 0.15,0.
5 atomic% ≦ x ≦ 15 atomic%, 7 atomic% ≦ v ≦ 20 atomic%, 0 atomic% ≦ z ≦ 9.5 atomic%, 2 atomic% ≦ w ≦ 14
More preferably, it is atomic%. Further, a, x, v, z, and w indicating the above composition ratios are 0 ≦ a ≦ 0.1, 0.5 atomic% ≦ x ≦ 15 atomic%, 10 atomic% ≦ v ≦ 15.5 atomic%, 0.5 atomic% ≦ z ≦ 6 atomic%, 4 atomic% ≦ w ≦ 11
More preferably, it is atomic%.

Examples of the insulating material include liquid or powdery organic substances such as epoxy resin, silicon resin, and PVA (polyvinyl alcohol), water glass, oxide glass powder, and glassy substances formed by a sol-gel method. Alternatively, a mixture thereof can be used. Further, a stearate such as zinc stearate, calcium stearate, etc. which plays a role of a lubricant together with insulation can be used at the same time. The mixing ratio of the insulating material to be mixed is 1
A range from 5% by weight to 5% by weight is preferred. Further, the particle diameter of the metallic glass alloy powder is preferably in a range of 45 μm or more and 300 μm or less.

According to the above method for manufacturing a dust core, the core precursor is heat-treated in a temperature range of (T _g -170) K or more and (T _g ) K or less, so that crystallization of the metallic glass alloy is prevented. Since the internal stress of the metallic glass alloy or the magnetic core precursor generated in the powder manufacturing process or the molding process can be removed or reduced, a dust core having a low coercive force can be manufactured. In the method for producing a dust core of the present invention, the core precursor, it is preferable to heat treatment at (T _g -150) K or more (T _g -50) K or lower. When heat treatment is performed in this temperature range, for example, a dust core having a coercive force of 100 A / m or less can be obtained.

In the method for producing a dust core of the present invention, it is more preferable that the above-mentioned core precursor is heat-treated at a temperature of (T _g -140) K or more and (T _g- 50) K or less. When heat treatment is performed in this temperature range, for example, a dust core having a coercive force of 80 A / m or less can be obtained.

The above-mentioned magnetic core precursor is represented by (T _g -90)
More preferably, the heat treatment is performed at a temperature of K or more and ( _Tg- 50) K or less. When heat treatment is performed in this temperature range, for example, a dust core having a coercive force of 40 A / m or less can be obtained.

[0023]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a dust core according to a first embodiment of the present invention; The dust core according to the embodiment of the present invention has ΔT _x = T _x −T _g.
(Wherein T _x is the crystallization onset temperature, T _g is. Showing the glass transition temperature) be the temperature interval [Delta] T _x of the supercooled liquid of the formula of 20K or more, and Fe, and Ga, P, C , Si,
A powder of a metallic glass alloy containing one or more elements Q of B and having a structure having an amorphous phase as a main phase, and an insulating material are mixed and molded. Further, as the metallic glass alloy, the specific resistance is 1.5 μΩ.
M is preferred.

The shape of the dust core may be, for example, an annular core 1 as shown in FIG. 1, but the shape is not limited to this, and may be an oval or elliptical ring. Further, it may be substantially E-shaped in plan view, substantially U-shaped in plan view, substantially I-shaped in plan view, or the like.

This dust core is made of a metallic glass alloy powder bound by an insulating material. The metallic glass alloy powder is present in the structure, and the metallic glass alloy powder is melted. It does not constitute a uniform tissue. Further, in the powder of the metallic glass alloy, it is preferable that individual particles constituting the powder are insulated by an insulating material. As described above, since the powder magnetic core includes a mixture of the powder of the metallic glass alloy and the insulating material, the specific resistance of the powder magnetic core itself is increased by the insulating material, the eddy current loss is reduced, and in the high frequency region, The decrease in magnetic permeability is reduced.

When the temperature interval ΔT _x of the supercooled liquid of the metallic glass alloy is less than 20 K, the crystallization does not occur during the heat treatment performed after the metallic glass alloy powder and the insulating material are mixed and compression molded. It becomes difficult to sufficiently reduce the internal stress. When ΔT _x is 20K or more, the heat treatment temperature can be lowered, the decomposition of the insulating material can be prevented, and an increase in loss due to the decomposition of the insulating material can be suppressed.

In particular, the dust core of the present invention has a coercive force of 80 A
/ M or less, more preferably 40 A / m or less.

The insulating material constituting the dust core of the present invention increases the specific resistance of the dust core, and binds a metallic glass alloy powder to maintain the shape of the dust core. It is preferable to use a material that does not cause a large loss. For example, liquid or powdery organic substances such as epoxy resin, silicone resin, phenol resin, urea resin, melamine resin, PVA (polyvinyl alcohol), and water glass (Na ₂ O— SiO ₂ ), oxide glass powder (Na ₂ O—B ₂₎
O ₃ —SiO ₂ , PbO—B ₂ O ₃ —SiO ₂ , PbO—BaO—
_{SiO 2, Na 2 O-B} 2 O 3 -ZnO, CaO-BaO-Si
O ₂ , Al ₂ O ₃ —B ₂ O ₃ —SiO ₂ , B ₂ O ₃ —SiO ₂ ), and glassy substances (SiO ₂ , Al ₂
O _3, ZrO _2, TiO ₂ or the like as a main component), and the like. In addition, a stearate (zinc stearate, calcium stearate, barium stearate, magnesium stearate, aluminum stearate, or the like) that plays a role of a lubricant together with insulation can be used at the same time.

Further, the metal core constituting the dust core of the present invention is
The lath powder is ΔT_x= T_x-T _g(However, T_xIs a crystal
Onset temperature, T_gIndicates a glass transition temperature. ) Expression
Temperature interval ΔT of the supercooled liquid_xIs over 20K
And Fe, Ga, and one or more of P, C, Si, and B
It has a structure containing the above element Q and an amorphous phase as a main phase.
It is obtained by grinding a thin strip of metallic glass alloy
Mist on a cooling roll rotating a molten metal and metallic glass alloy
What was obtained by spraying and cooling in a shape, metallic glass alloy
Blows out the molten metal in a mist with high-pressure gas and cools it.
Mist of molten metal or metallic glass alloy
It is obtained by blowing out and cooling. this
Metallic glass alloy powder has the above amorphous phase as the main phase
It is made of a soft magnetic material with low coercive force
Shows sex.

Further, this metallic glass alloy has a remarkable temperature interval of ΔT _x of 40 K or more, furthermore, 50 K or more depending on the composition, and has a specific resistance of 1.5 μΩ · m or more, It is completely unexpected from other alloys known from the findings so far, has excellent soft magnetic properties at room temperature, and is a completely new one not seen in the findings so far.

In the metallic glass alloy according to the present invention, the temperature interval ΔT _x of the supercooled liquid is a state in which only the atomic vibration occurs while the molten metal maintains the liquid structure. The presence of _x indicates that atoms are less likely to move in the metallic glass alloy, that is, it is harder to crystallize. In a metallic glass alloy having a large temperature interval ΔT _x of the supercooled liquid, atoms do not easily move when the molten metal is cooled, so that the supercooled liquid state in which the molten molten metal is solidified becomes very wide. The metallic glass alloy used in the present invention has a large supercooled liquid region on the low temperature side of the crystallization start temperature Tx when cooled from the molten state because the temperature interval ΔTx of the supercooled liquid is large, and crystallizes. When the temperature interval .DELTA.Tx of the supercooled liquid region has passed without a decrease in temperature, the temperature reaches the glass transition temperature Tg and an amorphous phase is easily formed. Therefore, it is possible to sufficiently form an amorphous phase even at a relatively low cooling rate. For example, a thin metal glass alloy obtained by a liquid quenching method such as a single roll method having a relatively high cooling rate can be used. In addition to the band, a powder of a metallic glass alloy having an amorphous phase as a main phase can be obtained by pulverizing a bulk body of a metallic glass alloy obtained by a casting method or the like.

As an example of a metallic glass alloy suitably used for the dust core of the present invention, an alloy containing Fe as a main component and Ga and an element Q can be given. As the element Q, one or more elements of P, B, C, and Si are used, and the element Q essentially contains at least the element B of P, B, C, and Si. Well,
At least one element of P, B, and C excluding Si may be used.

The metallic glass alloy used in the present invention can be represented by, for example, the following composition formula. _{(Fe 1-a T a)} 100-xy Ga x Q y However, T is Co, and one or both of Ni, Q is P, C, Si, be one or more elements of B A, x, and y indicating the composition ratio are 0 ≦ a ≦ 0.15, x
≦ 20 at%, y ≦ 50 at%.

When the composition ratios a, x, and y are 0 ≦ a ≦
0.15, x ≦ 20 at%, 5 at% ≦ y ≦ 50 at%
And more preferably a, x,
It is more preferable that y satisfies 0 ≦ a ≦ 0.15, 0.5 atomic% ≦ x ≦ 15 atomic%, and 7 atomic% ≦ y ≦ 35 atomic%.

The metallic glass alloy used in the present invention can be represented by the following composition formula. _{(Fe 1-a T a)} 100-xvzw Ga x (P 1-b Si b) v C z B
_{w where} T is one or both of Co and Ni, and a, b, x, v, z, and w indicating the composition ratio are 0 ≦ a ≦
0.15, 0 <b ≦ 0.8, x ≦ 20 atomic%, v ≦ 22
Atomic%, 0 atomic% ≦ z ≦ 10 atomic%, 1 atomic% ≦ w ≦ 2
0 atomic%.

A, b, x, v, z, w indicating the above composition ratios
Are 0 ≦ a ≦ 0.15, 0.1 ≦ b ≦ 0.35, 0.5
Atomic% ≦ x ≦ 15 atomic%, 7 atomic% ≦ v ≦ 20 atomic%,
More preferably, 0 atomic% ≦ z ≦ 9.5 atomic%, 2 atomic% ≦ w ≦ 14 atomic%, and 0 ≦ a ≦ 0.1, 0.1
≦ b ≦ 0.28, 0.5 atomic% ≦ x ≦ 15 atomic%, 10
It is more preferable that atomic% ≦ v ≦ 15.5 atomic%, 0.5 atomic% ≦ z ≦ 6 atomic%, and 4 atomic% ≦ w ≦ 11 atomic%.

The metallic glass alloy used in the present invention can be represented by the following composition formula. (Fe _1-a T _a ) _100-xvzw Ga _x P _v C _z B _{w where} T is one or both of Co and Ni, and a, x, v, z, and w indicating the composition ratio are 0. ≦ a ≦ 0.
15, x ≦ 20 at%, v ≦ 22 at%, 0 at% ≦ z
≦ 10 at%, 1 at% ≦ w ≦ 20 at%.

The composition ratios a, x, v, z, and w are as follows:
0 ≦ a ≦ 0.15, 0.5 atomic% ≦ x ≦ 15 atomic%, 7
Atomic% ≦ v ≦ 20 atomic%, 0 atomic% ≦ z ≦ 9.5 atomic%, 2 atomic% ≦ w ≦ 14 atomic%, more preferably 0 ≦ a ≦ 0.1, 0.5 atomic% ≦ x ≦ 15 atomic%,
10 atomic% ≦ v ≦ 15.5 atomic%, 0.5 atomic% ≦ z ≦
It is more preferable that 6 atomic%, 4 atomic% ≦ w ≦ 11 atomic%.

By the way, Fe-Al-Ga-CP-Si-B-based metallic glass alloys are conventionally known as one kind of metallic glass alloys. The conventional metallic glass alloy of the composition system is composed of Al, Ga, C,
P, Si and B are added. The metallic glass alloy used in the present invention with respect to the conventional metallic glass alloy contains Fe, Ga and the element Q, and removes Al from the conventional composition system without increasing the amount of Fe. Ga was increased in place of Al, and it was confirmed that an amorphous phase was formed even if Al, which was conventionally considered to be an essential element, was removed. It was found for the first time by the present inventor that they also express the interval ΔTx.

Ga is an essential element in the metallic glass alloy used in the present invention. In particular, when the composition ratio x of Ga is set to 20 atomic% or less, the temperature interval ΔTx of the supercooled liquid of the metallic glass alloy becomes 20K. Or more. Ga has a negative enthalpy of mixing with Fe, has a larger atomic radius than Fe, and has a smaller atomic radius than Fe.
It is difficult to be crystallized, and becomes a thermally stabilized state of the amorphous structure. Ga further increases the Curie temperature of the metallic glass alloy,
The thermal stability of various magnetic properties can be improved. G
The composition ratio x of a is preferably 20 atomic% or less, more preferably 0.5 atomic% or more and 15 atomic% or less. If the composition ratio x exceeds 20 atomic%, the amount of Fe relatively decreases and the saturation magnetization decreases, and the temperature interval ΔTx of the supercooled liquid is undesirably lost.

Fe is an element responsible for magnetism and, like Ga, is an essential element in the metallic glass alloy used in the present invention. Further, a part of Fe may be replaced with one or both elements T of Co and Ni.

The element Q is an element having an ability to form an amorphous phase. By adding the element Q to Fe and Ga to form a multi-component system, unlike the binary system of only Fe and Ga, the element Q is stably formed. An amorphous phase is formed. The composition ratio y of the element Q is preferably 50 atomic% or less, and more preferably 5 atomic% or more and 50 atomic%.
It is more preferably at most 7 atomic% and more preferably at most 35 atomic%. If the composition ratio y exceeds 50 atomic%, the amount of Fe relatively decreases and the saturation magnetization decreases, which is not preferable.

Among the elements Q, P has a particularly high ability to form an amorphous phase. Therefore, P always contains this P, and B, C, Si
When at least one of the above is included, the entire structure of the metallic glass alloy becomes an amorphous phase and the temperature interval ΔTx of the supercooled liquid is easily developed. Also P and S
When i is added at the same time, the temperature interval ΔTx of the supercooled liquid can be further improved.

When P and Si are added simultaneously, P and S
The composition ratio v indicating the total amount of i is preferably at most 22 at%, more preferably at least 7 at% and at most 20 at%, most preferably at least 10 at% and at most 15.5 at%. preferable. If the composition ratio v indicating the total amount of P and Si is within the above range, the temperature interval ΔTx of the supercooled liquid
Can be improved.

Si and P when P and Si are added simultaneously
Is preferably 0 <b ≦ 0.8 when the composition ratio v is 22 atom% or less, and the composition ratio v
Is not less than 7 atomic% and not more than 20 atomic%, 0.1 ≦ b ≦
Preferably, the composition ratio v is 10 atomic%.
0.1 ≦ b ≦ 0.28 when not less than 15.5 atomic%
It is preferable that If the composition ratio b exceeds 0.8, S
It is not preferable because the amount of i becomes excessive and the supercooled liquid region ΔTx may disappear. Incidentally, the concentration of Si in the metallic glass alloy at this time is 16 atomic% or less in a preferable case, 0.8 atomic% or more and 6.65 atomic% or less in a more preferable case, and 0.95 atomic% in a most preferable case. At least 4.34 atomic%.

When b and v, which indicate the composition ratio of P and Si, are within the above ranges, the temperature interval ΔTx of the supercooled liquid can be improved.

The composition ratio b of Si may be zero. That is, the element Q may be any one or more of P, B, and C. In this case, the composition ratio v of P is preferably 22 atomic% or less, more preferably 7 atomic% or more and 20 atomic% or less, and more preferably 10 atomic% or more and 1 atomic% or more.
Most preferably, it is set to 5.5 atomic% or less. If the composition ratio v of P is within the above range, the temperature interval ΔT of the supercooled liquid
x can be improved.

Further, the composition ratio z of C is preferably 0 to 10 atomic%, more preferably 0 to 9.5 atomic%, more preferably 0.5 to 6 atomic%. % Is most preferred. Further, the composition ratio w of B is preferably 1 atomic% or more and 20 atomic% or less, more preferably 2 atomic% or more and 14 atomic% or less, and most preferably 4 atomic% or more and 11 atomic% or less. preferable.

The metallic glass alloy having the above composition includes
Ge may be contained at 4 atomic% or less, and Nb, M
at least one of o, Hf, Ta, W, Zr and Cr
Species or more may be contained at 0 to 7 atomic%. In the metallic glass alloy having the above configuration used in the present invention, the temperature interval ΔTx of the supercooled liquid is 20K or more, and depending on the composition, ΔTx is 35K or more, and further, ΔTx is 50K or more. In addition, the metallic glass alloy having the above configuration used in the present invention may contain unavoidable impurities in addition to the elements shown in the above composition.

Next, an embodiment of a method for manufacturing a dust core according to the present invention will be described with reference to the drawings. In the method for producing a dust core of the present invention, the temperature of a supercooled liquid represented by the following formula: ΔT _x = T _x −T _g (where T _x represents a crystallization start temperature and T _g represents a glass transition temperature). When the interval ΔT _x is 20K or more,
e, Ga, and one or more elements Q of P, C, Si, and B, and a powder manufacturing process of manufacturing a metal glass alloy powder having an amorphous phase as a main phase; An insulating material is added to and mixed with the powder of the metallic glass alloy, the mixture is compression-molded to form a magnetic core precursor, and the magnetic core precursor is subjected to (T _g -170) K or more and (T _g ) K A heat treatment step of removing the internal stress of the magnetic core precursor by heat treatment at the following temperature.

In the powder production step, for example, a metallic glass alloy powder is produced by pulverizing and classifying a metallic glass alloy ribbon (metallic glass alloy ribbon). The metallic glass alloy ribbon is manufactured by a so-called roll quenching method in which a molten metal of the metallic glass alloy having the above-described composition is jetted onto a cooling surface of a rotating cooling roll to be rapidly cooled. Next, the obtained metallic glass alloy ribbon is pulverized into powder. For the pulverization, a rotor mill, a ball mill, a jet mill, an atomizer, a grinder and the like can be used.

Next, the obtained pulverized product is classified to obtain a powder having a predetermined average particle size. The average particle size of the powder is 30
The range is preferably not less than μm, more preferably not less than 45 μm and not more than 300 μm. If the average particle size is less than 30 μm, the particle size becomes smaller, the influence of the demagnetizing field increases, the saturation magnetic flux density and the magnetic permeability of the dust core decrease, and the coercive force and core loss increase. In addition, contamination from a rotor mill or the like may occur during pulverization, which is not preferable. In addition, the average particle size is 300
If it exceeds μm, the particles constituting the powder become coarse, voids may remain in the structure of the dust core when the insulating material is mixed and compression molded, and the coercive force of the dust core increases. Not preferred. For classification, sieve, vibration sieve,
A sonic sieve, an airflow classifier or the like can be used.

As another example of the powder production process, a powder of a metallic glass alloy can be obtained by spraying a molten metal of the metallic glass alloy having the above composition in a mist state on a rotating cooling roll. In this case, powder can be easily obtained only by spraying the molten metal in a mist state on the cooling roll. At this time, the average particle size of the powder can be controlled by appropriately adjusting the rotation speed of the cooling roll, the temperature of the molten metal, the spraying conditions, and the like. Further, it can also be obtained by blowing a molten metal glass alloy of the above composition together with high-pressure gas in a mist state to cool it, or by blowing a molten metal glass alloy of the above composition into water in a mist state and cooling it.

Next, the above-mentioned insulating material is added to and mixed with the above-mentioned metallic glass alloy powder, and the mixture is compression-molded to form a magnetic core precursor. The mixing ratio of the insulating material in the mixture is preferably 1% by weight or more and 5% by weight or less. If the mixing ratio of the insulating material is less than 1% by weight, it is not preferable because the powder of the metallic glass alloy cannot be formed into a predetermined shape together with the insulating material. On the other hand, if the mixing ratio exceeds 5% by weight, the content of the metallic glass alloy in the dust core decreases, and the soft magnetic properties of the dust core deteriorate. Also, the solvent contained in the mixture before compression molding,
It is desirable to evaporate moisture and the like to form an insulating material layer on the surface of the metallic glass alloy powder.

Next, the mixture is compression-molded to produce a magnetic core precursor. A mold 10 as shown in FIG. 2 is used for manufacturing the magnetic core precursor. The die 10 includes a hollow cylindrical die 11, and an upper punch 12 and a lower punch 13 inserted into a hollow portion 11 a of the die 11. A cylindrical projection 12 a is provided on the lower surface of the upper punch 12, and the upper punch 12, the lower punch 13, and the die 11 are integrated to form an annular mold inside the mold 10. Then, the mold 10 is filled with the above-described mixture.

Next, a mixture of the metallic glass alloy powder and the insulating material filled in the mold 10 is heated to a predetermined temperature while applying a uniaxial pressure and compression-molded. In FIG.
The main part of an example of a spark sintering apparatus suitable for use in compression molding is shown. The discharge plasma sintering apparatus of this example includes a mold 10 filled with a mixture, a punch electrode 14 which supports the lower punch 13 of the mold 10 and serves as one electrode when a pulse current to be described later flows, and a mold 10. The upper punch 12 is pressed downward, and a punch electrode 15 serving as the other electrode through which a pulse current flows and a thermocouple 1 for measuring the temperature of the mixture in the mold 10.
7 as a main component. The discharge plasma sintering apparatus is housed in a chamber 18. The chamber 18 is connected to a vacuum exhaust device and an atmosphere gas supply device (not shown). It is configured so that it can be maintained under a desired atmosphere such as an inert gas atmosphere. Although an energizing device is omitted in FIG. 3, an energizing device provided separately is connected to the upper and lower punches 12 and 13 and the punch electrodes 14 and 15, and a pulse current is supplied from the energizing device to the punches 12 and 13.
It is configured to be able to conduct electricity through the punch electrodes 14 and 15.

Then, the mold 10 filled with the mixture containing the powder of the metallic glass alloy and the insulating material is set in a discharge plasma sintering apparatus, and the inside of the chamber 18 is evacuated. The compression molding is performed while applying a uniaxial pressure P to the mixture and simultaneously heating the mixture by applying a pulse current. In this discharge plasma sintering process, the temperature of the mixture can be quickly raised at a predetermined speed by the supplied current, and the compression molding time can be shortened, so that the amorphous phase of the metallic glass alloy is maintained. Suitable for compression molding.

In the present invention, the temperature at which the above mixture is subjected to compression molding varies depending on the type of insulating material and the composition of the metallic glass alloy, but water glass is used as the insulating material, and Fe ₇₀ Ga ₇ P _10.49 C is used as the metallic glass alloy. _3.45 B _5.75 Si _3.31
When a material having the following composition is used, the temperature must be 373 K (100 ° C.) or more in order to bind the metallic glass alloy with the insulating material, and the insulating material is melted and exudes from the mold 10. 623K (350
° C) or lower. When the insulating material seeps, the content of the insulating material in the dust core decreases, the specific resistance of the dust core decreases, and the magnetic permeability in a high frequency band decreases. 373K (100 ° C) or more 623K (350
If the mixture is compression-molded in a temperature range of not more than (° C.), the insulating material is appropriately softened, so that the mixture can be formed into a predetermined shape by binding the powder of the metallic glass alloy.

Regarding the uniaxial pressure P applied to the mixture during compression molding, if the pressure is too low, the density of the dust core cannot be increased, and a dense dust core cannot be formed. On the other hand, if the pressure is too high, the insulating material exudes, the content of the insulating material in the dust core decreases, the specific resistance of the dust core decreases, and the magnetic permeability in a high frequency band decreases.
Therefore uniaxial pressure P varies depending on the composition type and metallic glass alloy of the insulating material, P _10.49 Fe ₇₀ Ga ₇ as insulating material water glass, metal glassy alloy C _3.45 B _{5. 75} Si
_When a material having a composition of _3.31 is used, the pressure is preferably set to 600 MPa or more and 1500 MPa or less.
It is more preferable that the pressure is not less than a and not more than 900 MPa. In this way, an annular core precursor is obtained.

Next, a heat treatment step of heat-treating the above-mentioned core precursor to remove the internal stress of the core precursor is performed. When the core precursor is heat-treated in a predetermined temperature range, the internal stress of the core precursor itself generated in the powder manufacturing process and the molding process and the internal stress of the metallic glass alloy powder contained in the core precursor can be removed. Thus, a dust core having a low coercive force can be manufactured. The heat treatment temperature, (T _g -170) K or more (T _g) K more preferably in the range, (T _g -150) K or more (T _g -50) K the range is more preferable, (T _g -
140) K or more (T _g -50) K is more preferably the range, (T _g -90) K or more (T _g -50) K following ranges are most preferred.

The precursor of the magnetic core is (T _g -150) K or more (T _g
When the heat treatment is performed in a temperature range of −50) K or less, for example, a dust core having a coercive force of 100 A / m or less can be manufactured, and at a temperature of (T _g −140) K to (T _g −50) K, Heat treatment, for example, the coercive force can be obtained following powder core 80A / m, more the core precursor (T _g -
90) When K or more (T _g -50) treated at K below the temperature can be for example the coercive force is obtained the following powder core 40A / m.

If the heat treatment temperature is lower than (T _g -170) K, the internal stress of the magnetic core precursor cannot be sufficiently removed, which is not preferable. If the heat treatment temperature exceeds (T _g ) K, the metallic glass alloy crystallizes, It is not preferable because the coercive force increases.

For example, Fe ₇₀ Ga ₇ P _10.49 C _3.45 B _5.75
In the case of a metallic glass alloy having a composition of Si _3.31 , the heat treatment temperature is preferably in the range of 573 K (300 ° C.) to 743 K (470 ° C.), and 593 K (320 ° C.) to 6 ° C.
More preferably, the temperature is in the range of 93 K (420 ° C.),
More preferably, the range is from 603K (330 ° C) to 693K (420 ° C), and more preferably from 653K (380 ° C) to 6K.
Most preferably, it is in the range of 93 K (420 ° C.).
By performing the heat treatment in this manner, the annular dust core of the present invention is obtained.

Since the dust core thus obtained contains the metallic glass alloy powder having the above constitution, it has excellent soft magnetic properties at room temperature and shows better soft magnetic properties by heat treatment. Things. Because of this, excellent
As a material having soft magnetic characteristics, the powder magnetic core can be applied as a magnetic core of various magnetic elements, and a magnetic core having excellent soft magnetic characteristics as compared with conventional materials can be obtained.

In the above description, a method in which a mixture containing a powder of a metallic glass alloy and an insulating material is compression-molded by a discharge plasma sintering apparatus is used. The dust core of the present invention can also be obtained by compression molding by a method such as extrusion.

In the above description, a method of manufacturing an annular dust core using a mold has been described. However, the present invention is not limited to this.
Dust cores of various shapes may be manufactured by cutting into a shape such as an annular shape, a bar shape, a substantially E-shape in plan view, and a substantially U-shape in plan view.

According to the dust core of the embodiment, since the powder of the metallic glass alloy having the above structure and the insulating material are mixed and formed, the specific resistance of the entire dust core is increased by the insulating material. As a result, the core loss of the dust core can be reduced by reducing the eddy current loss, and the decrease in the magnetic permeability in a high frequency band can be suppressed. In the dust core of the embodiment, the specific resistance is 1.5 μΩ.
In the case of using a metallic glass alloy of m or more, the eddy current loss in the metallic glass alloy particles at high frequency is reduced, and a dust core having a lower core loss can be formed.

According to the method for manufacturing a dust core of the embodiment, the core precursor is heat-treated in a temperature range of (T _g -170) K or more and (T _g ) K or less. In addition to removing the internal stress of the metallic glass alloy or the magnetic core precursor generated in the above, crystallization of the metallic glass alloy can be prevented, and a dust core having a low coercive force can be manufactured.

[0069]

[Example] Fe, Ga, Fe-C alloy, Fe-P alloy,
B and Si are each weighed to a predetermined amount as a raw material,
Under an atmosphere, these raw materials were melted by a high-frequency induction heating device to produce an ingot having a composition of Fe ₇₀ Ga ₇ P _10.49 C _3.45 B _5.75 Si _3.31 . This ingot is put into a crucible and melted, and a melt is blown out from a nozzle of the crucible into a rotating roll under a reduced-pressure Ar atmosphere, and the roll is rapidly cooled by a single roll method to form an amorphous phase structure having a width of 15 mm and a thickness of 20 μm. A ribbon of metallic glass alloy was obtained. This was pulverized in the air using a rotor mill, and those having a particle size in the range of 45 to 300 μm were sieved and classified to obtain a metallic glass alloy powder.

Next, 1 part by weight of calcium stearate as an insulating material and 2 parts by weight of water glass were mixed with 97 parts by weight of the metallic glass alloy powder to form a mixture. The mixture was dried at 473 K (200 ° C.) for 1 hour in the atmosphere and pulverized. After filling this mixture into a mold made of WC shown in FIG. 2, the interior of the chamber was set to a reduced pressure atmosphere of 6.6 × 10 ⁻³ Pa using a discharge plasma sintering apparatus shown in FIG. , 13 at molding pressure P _S 600MP
a, pressurizing to 900 MPa and applying a pulse current from an energizing device to bring the mixture to room temperature ((298K (25K
° C)) to 573K (300 ° C), 623K (350 ° C
Was heated to a molding temperature T _S. Then, the above molding temperature T _S to the mixture while applying the above molding pressure P _s of about 8
The compression molding was carried out by holding for minutes. Then, the heat treatment temperature T _a is 573K (300 ℃) ~723K (45
(0 ° C.) for 3600 seconds to produce various dust cores. The shape of this dust core has an outer diameter of 12 mm and an inner diameter of 6 mm.
mm and a thickness of 2 mm.

(Physical Properties of Metallic Glass Alloy Powder) FIG. 4 shows the results of X-ray diffraction measurement of the ribbon and powder of the metallic glass alloy having the composition of Fe ₇₀ Ga ₇ P _10.49 C _3.45 B _5.75 Si _3.31 . As is evident from FIG. 4, the X-ray diffraction patterns of the metallic glass alloy ribbon and the powder all show broad patterns, and both have a structure mainly composed of an amorphous phase. I understand. It can be seen that even when the ribbon is pulverized to form a metallic glass alloy powder in this manner, the amorphous state is maintained without precipitation of the crystalline phase.

FIG. 5 shows the DSC curves (Differential scanning ca.) of the ribbon and powder of the metallic glass alloy having the above composition.
loriemeter: A curve obtained by differential scanning calorimetry (heating rate during measurement: 40 K / min). From FIG. 5, the DSC curve of the metallic glass alloy ribbon having the above composition shows a glass transition temperature T _g due to a glass transition at 740 K.
Crystallization starting temperature T _x by crystallization is observed K. At 650 K, an endothermic peak due to the Curie temperature _Tc is observed. The temperature interval ΔTx of the supercooled liquid represented by ΔT _x = T _x −T _g was 60K. In addition, the DSC curve of the glassy alloy powder of the above composition, the glass transition temperature T _g by the glass transition was observed at 743K, 802
Crystallization starting temperature T _x by crystallization is observed K. An endothermic peak due to the Curie temperature _Tc is observed at 649K. The temperature interval ΔTx of the supercooled liquid represented by ΔT _x = T _x −T _g was 59K. Thus, Fe _{70
Ga 7 P 10.49 C 3.45 B 5.75} Si in metallic glass alloy ribbon and powder of _3.31 a composition exists supercooled liquid region in a wide temperature range below the crystallization temperature T _x, at ΔT _x = T _x -T _g The values shown are large, indicating that alloys of this system composition have high amorphous forming ability and high thermal stability.

(Dependence of Magnetic Properties on Heat Treatment Temperature Ta) Next, FIGS. 6 and 7 show the dust cores before heat treatment (immediately after compression molding) and after heat treatment (Fe ₇₀ Ga ₇ P _10.49 C _3.45 B _5.75 Si
_The dependence of the magnetic flux density (B _2.4k ) and coercive force (Hc) on the heat treatment temperature of a dust core manufactured using a powder of a metallic glass alloy having a composition of _3.31 and an insulating material are shown below. Note that in FIGS. 6 7, ■ the molding temperature T _s is 573K (30
0 ° C.), the molding pressure P _S is 900 MPa,
Indicates that the molding temperature T _s is 623 K (350 ° C.) and the molding pressure P _S
6 There is the case of 600 MPa, ▲ molding temperature T _s is
23K (350 ° C.) and a molding pressure P _S of 900 MPa. During the heat treatment, the time for which the heat treatment temperature Ta was maintained was 3600 seconds. The magnetic flux density (B _2.4k ) shown in FIG. 6 is a magnetic flux density at an applied magnetic field of 2.4 kA / m.

For comparison, Fe ₇₀ Ga ₇ P _10.49 C
_3.45 B _5.75 Si A dust core (the dust powder of the comparative example) was prepared in the same manner as the above-described method of manufacturing the dust core except that a powder of Fe (a powder of carbonyl iron) was used instead of the powder of the metallic glass alloy having the composition of _3.31. Magnetic core). 8 and 9 show the dependence of the magnetic flux density ( _B2.4k ) and the coercive force (Hc) on the heat treatment temperature of the heat-treated dust core (the dust core manufactured using the Fe powder and the insulating material). Are respectively shown. 8 and 9, ■ indicates a case where the molding temperature T _s is 673K (400 ° C.) and a molding pressure P _S is 600 MPa, and ● indicates a molding temperature T _s.
There 623K (350 ℃), molding pressure P _S is 600MP
It is the case of a, ▲ molding temperature T _s is 573K (30
0 ° C.), when the molding pressure P _S is 900 MPa,
Indicates that the molding temperature T _s is 573 K (300 ° C.) and the molding pressure P _S
Is 600 MPa. During the heat treatment, the time for which the heat treatment temperature Ta was maintained was 3600 seconds. The magnetic flux density (B _2.4k ) shown in FIG.
This is the magnetic flux density at A / m.

As shown in FIG. 6, Fe ₇₀ Ga ₇ P _10.49 C
_3.45 B _5.75 powder and dust core produced using the insulating material of Si _3.31 a composition of metallic glass alloys, regardless of the molding conditions such as molding temperature T _S and the molding pressure P _S, the magnetic flux density by the heat treatment (B _2.4 It can be seen that _k ) is higher. Also, the dust core after the heat treatment, the heat treatment temperature T _a exceeds 623 K (350 ° C.), the magnetic flux density (B _2.4k)
It can be seen that is greatly increased. The molding condition is T _s
= 623K (350 ℃), those of P _S = 900 MPa, the heat treatment temperature T _a exceeds 643K (370 ℃) magnetic flux density (B _{2. 4k)} is slightly reduced. FIG.
As shown in the figure, Fe ₇₀ Ga ₇ P _10.49 C _3.45 B _5.75 Si
It can be seen that the coercive force (Hc) of the dust core manufactured using the powder of the metallic glass alloy having the composition of _3.31 and the insulating material is reduced by the heat treatment regardless of the molding conditions. In addition, for the dust core after the heat treatment, the heat treatment temperature T _a
Is in the range of 593K to 693K and the coercive force (Hc) is 100
Shows the following A / m, the heat treatment temperature T _a is 603K
Coercive force in the range of ~693K (Hc) has shown the following 80A / m, a coercive force annealing temperature T _a is in the range of 653K~693K (Hc) has shown the following 40A / m, also, 673 K ( 400 ° C), the coercive force (Hc) is about 1
The minimum is shown at 5 A / m.

On the other hand, as shown in FIG. 8, the powder magnetic core of the comparative example manufactured by using the Fe powder and the insulating material has a molding temperature T
Regardless of the molding conditions such as _S and the molding pressure P _S, it can be seen that the magnetic flux density (B _2.4k) hardly changes by heat treatment. Further, as shown in FIG. 9, the powder magnetic core of the comparative example shows that the coercive force (Hc) hardly changes due to the heat treatment and shows a coercive force of 100 A / m or more regardless of the molding conditions.

(Frequency (f) Characteristics of Permeability and Core Loss)
FIG. 10 shows the frequency (f) characteristics of the magnetic permeability (μ ′) of a dust core manufactured using a metallic glass powder of Fe ₇₀ Ga ₇ P _10.49 C _3.45 B _5.75 Si _3.31 and an insulating material. FIG.
FIG. 1 shows the frequency (f) characteristics of the core loss (W) of a dust core manufactured using a metallic glass powder of Fe ₇₀ Ga ₇ P _10.49 C _3.45 B _5.75 Si _3.31 and an insulating material. The core loss here is a frequency of 10 to 100 kHz and a magnetic flux density (Bm).
It was measured under the condition of 0.1T. Note that in FIG. 10 and FIG. 11, ■ the molding temperature T _s is 573K
(300 ° C.), molding pressure P _S is 900 MPa, the case the heat treatment temperature T _a is 653K of (380 ℃), ● the molding temperature T _s is 623K (350 ℃), molding pressure P _S is 60
0 MPa, a case the heat treatment temperature T _a is 683K (410 ℃), ▲ molding temperature T _s is 623K (350 ℃),
Molding pressure P _S is 900 MPa, the heat treatment temperature T _a is 683K
(410 ° C.). During the heat treatment, the time for which the heat treatment temperature Ta was maintained was 3600 seconds.

For comparison, FIG. 12 shows the frequency (f) characteristics of the magnetic permeability (μ ′) of the dust core of the comparative example manufactured using Fe powder (carbonyl iron powder) and an insulating material. . FIG. 13 shows Fe powder (carbonyl iron powder).
7 shows the frequency (f) characteristics of the core loss (W) of the powder magnetic core of the comparative example manufactured by using the insulating material. The core loss here is a frequency of 10 to 100 kHz, a magnetic flux density (Bm) of 0.
It was measured under the condition of 1T. Note that, in FIGS. 12 and 13, ■ the molding temperature T _s is 673 K (40
0 ° C.), molding pressure P _S is 600 MPa, the case the heat treatment temperature T _a is 673K of (400 ℃), ● the forming temperature T _s
There 623K (350 ℃), molding pressure P _S is 600MP
a, a case the heat treatment temperature T _a is 673K of (400 ℃), ▲ molding temperature T _s is 573K (300 ℃), molding pressure P _S is 900 MPa, the heat treatment temperature T _a is 673K (40
0 ℃) is a case of, ◆ 573K is the molding temperature T _s
(300 ° C.), molding pressure P _S is 600 MPa, the heat treatment temperature T _a is the case 673K (400 ℃). During the heat treatment, the time for which the heat treatment temperature Ta was maintained was 3600 seconds.

As shown in FIG. 10, a dust core according to an embodiment of the present invention (a dust core manufactured using metallic glass powder of Fe ₇₀ Ga ₇ P _10.49 C _3.45 B _5.75 Si _3.31 and an insulating material)
Indicates that the range (frequency band) in which the graph indicating the relationship between the magnetic permeability and the frequency shows a flat value is wide), and
Even in a high frequency band of 00 kHz or more, the decrease rate of the magnetic permeability (μ ′) is small, and it can be seen that the frequency (f) characteristic of the magnetic permeability (μ ′) is excellent. It can be seen that such characteristics can be exhibited regardless of the molding conditions such as the molding temperature T _S and the molding pressure P _S. In the dust core of _{Example, ■ (T s = 573K,} P S = 900MPa, T
_a = the case of 653K), in a wide frequency band 0.3~10000kHz has become permeability constant _{and, ● (T s = 623K,} P S = 600MPa, T a =
683K), the magnetic permeability is constant in a wide frequency band of 0.3 to 1000 kHz.
(T _s = 623K, molding pressure P _S is 900 MPa, the heat treatment temperature T _a is 683K) For, 0.3～300KH
The magnetic permeability is constant in a wide frequency band of z. Therefore, the dust core of the embodiment of the present invention is effective when used for a core component requiring a constant magnetic permeability up to a high frequency band, such as a transformer core for a switching power supply and a smoothing choke core.

On the other hand, as shown in FIG.
The dust core of the comparative example manufactured using the insulating material is the same as that of the example.
Graph showing the relationship between magnetic permeability and frequency
Flat range (frequency band) is small and comparative example
圧 (T_s = 673K, P_S= 600MP
a, T_a= 673K), the higher the frequency,
, The permeability is greatly reduced._s = 623
K, P_S= 600MPa, T _a= 673K), 1
When the frequency exceeds 0 kHz, the magnetic permeability sharply decreases.
(T_s = 573K, P_S= 900MPa, T_a= 673
K) or ◆ (T_s= 573K, P_S= 600MP
a, T_a= 673K), exceeds 200 kHz
And the magnetic permeability sharply decreases. In addition, the powder magnetic
The mind is in the high frequency band of 1000 kHz or more
In this case, the magnetic permeability is lower than that of the dust core of the embodiment of the present invention.
You can see that.

As is clear from the results shown in FIGS. 11 and 13, the dust core (Fe ₇₀ Ga ₇ P _10.49) of the embodiment of the present invention was used.
A powder magnetic core manufactured using a metal glass powder of C _3.45 B _5.75 Si _3.31 and an insulating material) is 10 kHz to 100 kHz.
2 shows a core loss lower than the dust core of the comparative example in the frequency band of FIG. Further, in the powder magnetic core of the example of the present invention, the core loss in the vicinity of 10 kHz to 20 kHz is smaller by one digit or more than the core loss of the powder magnetic core of the comparative example. Therefore, it can be seen that the dust core of the embodiment of the present invention has excellent core loss from low frequencies to high frequencies.

(C, P, Si,
Investigation of composition dependence of B) Fe, Ga, Fe-C alloy, Fe-
P alloys, B, and Si are weighed in predetermined amounts as raw materials,
Under a reduced pressure Ar atmosphere, these raw materials were melted by a high-frequency induction heating apparatus to produce various ingots of Fe ₇₀ Ga ₇ (P, Si) _v C _z B _w composition. This ingot is put into a crucible and melted, and the molten metal is blown out from a nozzle of the crucible into a rotating roll under a reduced-pressure Ar atmosphere to rapidly cool the roll. A ribbon of metallic glass alloy was obtained. The compositions of the ribbons of various metallic glass alloys obtained here were as follows. Fe ₇₀ Ga ₇ P _8.89 C _5.57 B _5.09 Si _3.45 , Fe ₇₀ Ga
₇ P _6.11 C _9.13 B _4.45 Si _3.31 , Fe ₇₀ Ga ₇ P _7.94 C
_5.57 B _6.41 Si _3.08 , Fe ₇₀ Ga ₇ P _10.64 C _3.14 B _5.09
Si _4.13 , Fe ₇₀ Ga ₇ P _10.55 C _5.57 B _2.79 Si _4.09 ,
Fe ₇₀ Ga ₇ P _8.46 C _9.08 B _1.64 Si _3.82 , Fe ₇₀ Ga ₇
P _7.91 C _3.38 B _8.12 Si _3.59 , Fe ₇₀ Ga ₇ P _8.89 C
_0.97 B _9.69 Si _3.45 , Fe ₇₀ Ga ₇ P _10.49 C _0.97 B _7.39
Si _4.15 , Fe ₇₀ Ga ₇ P _12.2 C _0.97 B _5.09 Si _4.74 ,
Fe ₇₀ Ga ₇ P _12.2 C _3.27 B _2.79 Si _4.74 , Fe ₇₀ Ga
₇ P _8.89 C _2.12 B _8.54 Si _3.45 , Fe ₇₀ Ga ₇ P _10.52 C
_2.37 B _6.03 Si _4.08 , Fe ₇₀ Ga ₇ P _11.61 C _3.27 B
_6.24 Si _1.88 , Fe ₇₀ Ga ₇ P _6.05 C _4.68 B _8.34 Si
_3.93 , Fe ₇₀ Ga ₇ P _5.36 C _3.53 B _10.64 Si _3.47 , F
e ₇₀ Ga ₇ P _5.65 C _1.23 B _12.46 Si _3.66

With respect to the obtained metallic glass alloy ribbon,
DSC measurement (Differential scanning caloriemetry) was performed to measure the glass transition temperature Tg and the crystallization start temperature Tx, and the temperature interval ΔTx of the supercooled liquid was obtained. The heating rate of DSC measurement is 0.67K
/ Sec. FIG. 14 shows the composition dependence of the glass transition temperature Tg, FIG. 15 shows the composition dependence of the crystallization start temperature Tx, and FIG.
The composition dependence of the temperature interval ΔTx of the supercooled liquid is shown in FIG.

The subscripts in the plots in the triangular composition diagrams in FIGS. 14 to 16 show the values of the glass transition temperature Tg, the crystallization start temperature Tx, and the temperature interval ΔTx of the supercooled liquid, respectively. Further, in the triangular composition diagrams of FIGS. 14 to 16, isolines are drawn, and subscripts on or near the isolines indicate the values of these isolines.

As shown in FIG. 14, the glass transition temperature Tg increases with the increase of B, and the isothermal line of Tg of 750 K
Is in the range of 1.5 to 10.5 atomic% of the composition ratio w. Further, as shown in FIG. 15, the crystallization start temperature Tx rises with the increase of B as in the case of Tg, and the 800 K isoline of Tx indicates that the composition ratio w of B is 4.5 to 10.5 atom. % Range. Then, as shown in FIG. 16, the Tg of 7 shown in FIG.
The range enclosed by the 50K isoline and the Tx 800K isoline shown in FIG. 15 corresponds to the range of the ΔTx 50K isoline, and within this range, the temperature interval ΔTx of the supercooled liquid. Exceeds 50K, and in particular, Fe ₇₀ Ga ₇ P _11.61 C _3.27 B
_It can be seen that ΔTx of the alloy having the composition of _6.24 Si _1.88 indicates 60K.

[0086]

As described in detail above, the pressure of the present invention
The powder core has a temperature interval ΔT of the supercooled liquid. _xIs over 20K
And Fe, Ga, and one of P, C, Si, and B
Containing at least one kind of element Q and having an amorphous phase as a main phase
Lath alloy powder and insulating material are mixed and molded
Therefore, the specific resistance of the whole dust core is increased by the insulating material
Can reduce the eddy current loss and core loss of the dust core
In the high frequency band
A decrease in magnetic permeability can be suppressed. The pressure of the present invention
In a powder magnetic core, a metal core with a specific resistance of 1.5 μΩ
In the case of using lath alloy, metal at high frequency
Eddy current loss in glass alloy particles is reduced,
Thus, a powder magnetic core having a low hardness can be formed.

According to the method for manufacturing a dust core of the present invention, the core precursor is heat-treated in a temperature range of (T _g -170) K or more and (T _g ) K or less. The internal stress of the metallic glass alloy or the magnetic core precursor generated as described above can be removed, and crystallization of the metallic glass alloy can be prevented, so that a dust core having a low coercive force can be manufactured.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a dust core according to the present invention.

FIG. 2 is an exploded perspective view showing an example of a mold used when performing the method for manufacturing a dust core of the present invention.

FIG. 3 is a schematic view of a main part of a spark plasma sintering apparatus used when performing the method for manufacturing a dust core of the present invention.

FIG. 4 Fe ₇₀ Ga ₇ P _10.49 C _3.45 B _5.75 Si _3.31
It is a figure which shows the X-ray-diffraction result of the metal glass alloy ribbon and powder of the composition which become.

FIG. 5: Fe ₇₀ Ga ₇ P _10.49 C _3.45 B _5.75 Si _3.31
It is a figure which shows the DSC curve of the metallic glass alloy ribbon and powder of composition.

FIG. 6 is a powder magnetic core (Fe ₇₀ Ga ₇ P _10.49 C) of the present invention.
It is a graph which shows the heat treatment temperature dependence of the magnetic flux density of the powder magnetic core manufactured using the powder of the metallic glass alloy of _3.45 B _5.75 Si _3.31 and an insulating material.

FIG. 7 is a powder magnetic core (Fe ₇₀ Ga ₇ P _10.49 C) of the present invention.
FIG. 3 is a graph showing the heat treatment temperature dependence of the coercive force of a dust core manufactured using a powder of a metallic glass alloy having a composition of _3.45 B _5.75 Si _3.31 and an insulating material;

FIG. 8 is a graph showing the heat treatment temperature dependence of the magnetic flux density of a dust core of the comparative example (a dust core manufactured using an Fe powder and an insulating material).

FIG. 9 is a graph showing the heat treatment temperature dependency of the coercive force of a dust core of the comparative example (a dust core manufactured using an Fe powder and an insulating material).

FIG. 10: Fe ₇₀ Ga ₇ P _10.49 C _3.45 B _5.75 Si _3.31
7 is a graph showing frequency (f) characteristics of magnetic permeability (μ ′) of a dust core manufactured using a metallic glass powder and an insulating material.

FIG. 11: Fe ₇₀ Ga ₇ P _10.49 C _3.45 B _5.75 Si _3.31
7 is a graph showing frequency (f) characteristics of core loss (W) of a dust core manufactured using a metallic glass powder and an insulating material.

FIG. 12 is a graph showing a frequency (f) characteristic of a magnetic permeability (μ ′) of a dust core of a comparative example manufactured using an Fe powder and an insulating material.

FIG. 13 is a graph showing a frequency (f) characteristic of a core loss (W) of a dust core of a comparative example manufactured using an Fe powder and an insulating material.

FIG. 14 is a triangular composition diagram showing the composition dependence of the glass transition temperature Tg of a ribbon of a metallic glass alloy having a composition of Fe ₇₀ Ga ₇ (P, Si) _v C _z B _w .

FIG. 15 is a triangular composition diagram showing the composition dependence of the crystallization start temperature Tx of a ribbon of a metallic glass alloy having a composition of Fe ₇₀ Ga ₇ (P, Si) _v C _z B _w .

FIG. 16 is a triangular composition diagram showing the composition dependence of the temperature interval ΔTx of a supercooled liquid in a ribbon of a metallic glass alloy having a composition of Fe ₇₀ Ga ₇ (P, Si) _v C _z B _w .

[Explanation of symbols]

 1 dust core

Claims (14)

[Claims] 1. A temperature interval ΔT _x of a supercooled liquid represented by the following equation: ΔT _x = T _x −T _g (where T _x indicates a crystallization start temperature and T _g indicates a glass transition temperature). And a powder of a metallic glass alloy containing Fe, Ga, and one or more elements Q of P, C, Si, and B and having a structure having an amorphous phase as a main phase; A dust core characterized by being mixed with a material and molded. 2. The specific resistance of the metallic glass alloy is 1.5.
2. The dust core according to claim 1, wherein the dust core is not less than μΩ · m. 3. The dust core according to claim 1, wherein the coercive force is 80 A / m or less. 4. The dust core according to claim 1, wherein the coercive force is 40 A / m or less. 5. The dust core according to claim 1, wherein the metallic glass alloy is represented by the following composition. _{(Fe 1-a T a)} 100-xy Ga x Q y However, T is Co, and one or both of Ni, Q is P, C, Si, be one or more elements of B A, x, and y indicating the composition ratio are 0 ≦ a ≦ 0.15, x
≦ 20 at%, y ≦ 50 at%. 6. The dust core according to claim 1, wherein the metallic glass alloy is represented by the following composition. _{(Fe 1-a T a)} 100-xvzw Ga x (P 1-b Si b) v C z B
_{w where} T is one or both of Co and Ni, and a, b, x, v, z, and w indicating the composition ratio are 0 ≦ a ≦
0.15, 0 <b ≦ 0.8, x ≦ 20 atomic%, v ≦ 22
Atomic%, 0 atomic% ≦ z ≦ 10 atomic%, 1 atomic% ≦ w ≦ 2
0 atomic%. 7. The dust core according to claim 1, wherein the metallic glass alloy is represented by the following composition formula. (Fe _1-a T _a ) _100-xvzw Ga _x P _v C _z B _{w where} T is one or both of Co and Ni, and a, x, v, z, and w indicating the composition ratio are 0. ≦ a ≦ 0.
15, x ≦ 20 at%, v ≦ 22 at%, 0 at% ≦ z
≦ 10 at%, 1 at% ≦ w ≦ 20 at%. 8. The temperature interval ΔT _x of the supercooled liquid represented by the formula ΔT _x = T _x −T _g (where T _x indicates the crystallization start temperature and T _g indicates the glass transition temperature) is 20K or more. Producing a powder of a metallic glass alloy containing Fe, Ga, and one or more elements Q of P, C, Si, and B, and having a structure having an amorphous phase as a main phase. Powder manufacturing process, adding an insulating material to the metallic glass alloy powder and mixing,
A forming step of forming a core precursor and the mixture compression molded to, the core precursor, (T _g -170) K or more (T _g) the internal stress of K was heat-treated at a temperature below the core precursor A method for producing a dust core, comprising: 9. The powder compact according to claim 8, wherein in the heat treatment step, the magnetic core precursor is heat-treated at a temperature of (T _g -150) K or more and (T _g -50) K or less. Manufacturing method of magnetic core. 10. The powder compact according to claim 8, wherein, in the heat treatment step, the magnetic core precursor is heat-treated at a temperature of (T _g -140) K or more and (T _g -50) K or less. Manufacturing method of magnetic core. 11. The powder compact according to claim 8, wherein in the heat treatment step, the magnetic core precursor is heat-treated at a temperature of (T _g -90) K or more and (T _g -50) K or less. Manufacturing method of magnetic core. 12. The metallic glass alloy according to claim 8, wherein said alloy has the following composition.
A method for manufacturing a dust core according to any one of claims 11 to 11. _{(Fe 1-a T a)} 100-xy Ga x Q y However, T is Co, and one or both of Ni, Q is P, C, Si, be one or more elements of B A, x, and y indicating the composition ratio are 0 ≦ a ≦ 0.15, x
≦ 20 at%, y ≦ 50 at%. 13. The method according to claim 8, wherein the metallic glass alloy has the following composition.
A method for manufacturing a dust core according to any one of claims 11 to 11. _{(Fe 1-a T a)} 100-xvzw Ga x (P 1-b Si b) v C z B
_{w where} T is one or both of Co and Ni, and a, b, x, v, z, and w indicating the composition ratio are 0 ≦ a ≦
0.15, 0 <b ≦ 0.8, x ≦ 20 atomic%, v ≦ 22
Atomic%, 0 atomic% ≦ z ≦ 10 atomic%, 1 atomic% ≦ w ≦ 2
0 atomic%. 14. The method according to claim 8, wherein said metallic glass alloy is represented by the following composition.
A method for manufacturing a dust core according to any one of claims 11 to 11. (Fe _1-a T _a ) _100-xvzw Ga _x P _v C _z B _{w where} T is one or both of Co and Ni, and a, x, v, z, and w indicating the composition ratio are 0. ≦ a ≦ 0.
15, x ≦ 20 at%, v ≦ 22 at%, 0 at% ≦ z
≦ 10 at%, 1 at% ≦ w ≦ 20 at%.