JPH0418712A - Magnetic shield material and dust core - Google Patents

Abstract

PURPOSE:To improve corrosion-proof property, and to obtain a magnetic shield material, having a very small magnetostriction constant, and a dust core by a method wherein the powder of soft magnetic alloy, having a microscopic crystal phase and specific composition, and a binding agent are contained therein. CONSTITUTION:Amorphous alloy powder is manufactured by high speed quenching the molten alloy which is indicated by the following formula. (Fe1-aNi100-x-y-z-p-qCuxSiyB2CrpM<1qo> provided that M<1> is V and/or Mn in the above-mentioned formula in the constitution of 0<=a<=0.5, 0.1<=x<=5, 6<=y<=20, 6<=z<=20, 15<=y+z<=30, 0.5<=p<=10, 0.5<=q<=10. The obtained flat type amorphous powder is heat-treated, and a microscopic crystal phase is formed. This amorphous alloy particles are flattened using a medium agitation mill.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides a magnetic shielding material containing a soft magnetic alloy, particularly a highly corrosion-resistant and low magnetostrictive Fe-based magnetomagnetic alloy powder, and a binder, and the powder thereof. Regarding the powder core used.

<Prior Art> The required characteristics for soft magnetic materials are becoming stricter year by year.

However, basically, high saturation magnetization, high magnetic permeability, and low iron loss are required. In order to satisfy these required properties, the soft magnetic material must satisfy the following properties.

(1) The magnetostriction constant 2.8 is small (λs-±5XIO
-6 or less).

(2) Small magnetocrystalline anisotropy.

Unless these two required characteristics are satisfied, the soft magnetic material may not have sufficient basic characteristics, or may not be usable at all depending on the application.

Incidentally, a magnetic shielding material is known in which powder of a soft magnetic material is dispersed in a binder, and the powder is coated on the binder.

Further, powder cores using the powder are also known.

However, in magnetic shielding materials and dust cores, stress is applied during the manufacturing process or during use, so the magnetostriction constant λs
is preferably zero or negative, for example 0 to -5X10-6.

On the other hand, Fe-based alloy soft magnetic materials are often used as soft magnetic materials;
Pure iron, silicon steel, sendust alloy, amorphous alloy, etc. are known, and are characterized by high saturation magnetic flux density.

Among these soft magnetic materials, Fe-based amorphous alloys have come to be widely used due to their characteristics of high saturation magnetic flux density and low loss.

However, since Fe-based amorphous alloys have a high magnetostriction constant, their applications are limited.

In particular, magnetic shielding cannot be used because it has the fundamental problem of greatly deteriorating its magnetic properties.

On the other hand, among amorphous alloys, there are alloys whose magnetostriction constant is almost zero, such as Co-based amorphous alloys. However, this alloy has the drawbacks of low saturation magnetic flux density and high cost. For this reason, its use has been limited to fields such as magnetic heads where the cost of the grinder is not an issue.

In order to solve these problems with amorphous alloys,
European Patent Publication No. 0271657 proposes a soft magnetic alloy consisting of a microcrystalline phase. This soft magnetic alloy is
First, an amorphous alloy is produced and then heat treated to form a microcrystalline phase.

This alloy is an invention that considerably improves the drawbacks of conventional Fe-based amorphous alloys. In particular, it is preferable that the saturation magnetostriction constant is greatly reduced.

<Problems to be Solved by the Invention> However, even with this alloy, the properties are still insufficient. In particular, there is a problem in that alloys with a magnetostriction constant of zero or negative cannot be produced, and therefore cannot be practically used for magnetic shielding materials or dust cores.

The above publication describes an example in which the magnetostriction constant becomes almost zero when the boron B content is around 5% (for example,
Fe74CIIINt)3si+Je alloy).

However, it is generally widely known that alloys with a boron B content of about 5% are difficult to become amorphous.

Further, such alloys have the disadvantage that their corrosion resistance, which is fundamentally important when using metal materials for magnetic shielding materials and dust cores, is extremely low.

The present invention relates to a soft magnetic alloy having a microcrystalline phase, which has significantly improved corrosion resistance, and has an extremely small magnetostriction constant, particularly a soft magnetic alloy whose magnetostriction constant is close to zero or exists in a negative range from zero. The present invention aims to provide a magnetic shielding material using soft magnetic alloy powder and a dust core.

<Means for Solving the Problems> Such objects are achieved by the following inventions (1) to (8).

(1) A magnetic shielding material characterized by containing powder of a soft magnetic alloy having a microcrystalline phase and having a composition represented by the following formula (I), and a binder.

[Formula (I)] (Fe+-aNlg) + oo-++-y-z-p-
qcUxslyBycrp-qCuxSiyBzCrp
M1q (However, in the above formula (I), M' is ■ and /
or Mn, and O≦a≦05. 0.1≦x≦5. 6≦y≦20. 6≦z≦20. 15≦, y+z≦30. 05≦p≦10. 0.5≦q≦10. ) (2) The above (
The magnetic shielding material described in 1).

(3) A magnetic shielding material comprising a powder of a soft magnetic alloy having a microcrystalline phase and a composition represented by the following formula (II) and a binder.

[Formula (H)] (Fel-aNlml +oo-x-y-*-p-qc
uxsLyBzcr'pM'QM”r (However, the above formula (
II), Ml is V and/or Mn,
M2 is Ti, Zr, Hf, Nb, Ta, Mo and W
One or more elements selected from 0≦a≦0.5. 0.1≦x≦5, O≦y≦20. 6≦z≦20. 15≦y+z≦30. 0.5≦p≦10. 0.5≦q≦10. 0≦r≦10. ) (4) The above (
3) The magnetic shielding material described in 3).

(5) A powder core formed from a soft magnetic alloy powder having a microcrystalline phase and having a composition represented by the following formula (I).

[Formula (■)] (Fel-aNIR)+ao-x-y-z-p-qcu
ys1yB1crpMO (However, in the above formula (I), Ml is V and/or Mn, O≦a≦0.5. 0.1≦x≦5. 6≦y≦20. 6≦z≦20. 15 ≦y+z≦30, 0.5≦p≦10, 0.5≦q≦10.) (6) The above (
5) The powder core described in 5).

(7) A powder core formed from a soft magnetic alloy powder having a microcrystalline phase and having a composition represented by the following formula (IT).

[Formula (II)] (Fel-aNla)+oo-x-y-z-p-qcl
Ixs1yB2crp-qCuxSiyBzCrpM1
qM2r (However, in the above formula (II), M' is ■ and/or Mn, and M2 is Ti, Zr, Hf, N
b, one or more elements selected from Ta, Mo, and W, and O≦a≦0.5. 0.1≦x≦5. 0≦y≦20. 6≦z≦20. 15≦y+z≦30. 0.5≦p≦10. 0.5≦q≦10. 0≦r≦10. ) (8) The powder core according to (7), wherein the magnetostriction constant λs is within ±5×10 −6 .

<Effect> The soft magnetic alloy used in the present invention is FeCuCr (V, Mn)SiB It is based on the composition of the system.

The soft magnetic alloy of the present invention is obtained by once forming the above-mentioned alloy into an amorphous alloy and then subjecting it to heat treatment to form a microcrystalline phase.

In the present invention, the soft magnetic alloy containing a microcrystalline phase is mixed with Cr, ■ and/or Mn, so that the magnetostriction is reduced.
In particular, the magnetostriction can be changed from zero to negative, and the corrosion resistance can be significantly improved.

Since such a soft magnetic alloy has such a small magnetostriction, it is most suitable for a magnetic shielding material containing soft magnetic alloy powder and a binder. In other words, even when stress is applied when the powder and binder are kneaded together in the production of magnetic shielding materials, when the binder hardens and shrinks, or when used as magnetic shielding materials, there is almost no deterioration in magnetic properties. , the magnetic shielding characteristics do not deteriorate.

Similarly, since there is almost no deterioration in magnetic properties due to the pressure during core manufacturing, it is suitable as a dust core.

<Specific configuration> Hereinafter, the specific configuration of the present invention will be explained in detail.

The soft 6H alloy of the present invention has a microcrystalline phase and has the following formula (I
).

[Formula (I)] (Fe+-aNla) 100-x-y-t, -p-q
cuxs1yBz'l;rp-qCuxSiyBz'Cr
pM1q However, in the above formula (I), Ml is ■ and/or Mn, and O≦a≦05. 0.1≦x≦5. 6≦y≦20. 6≦z≦20. 15≦y+z≦30. 0.5≦p≦10. 0, 5≦q≦10.

When Ni is contained, ductility and malleability are improved.
For this reason, when powdering with a media stirring mill described later,
It is possible to achieve a flattening that is suitable for use as a magnetic shielding material. Moreover, corrosion resistance is also improved by containing Ni.

When a exceeds the above range, the saturation magnetic flux density decreases. Note that preferably O≦a≦0.1.

Cu is an essential element when forming a microcrystalline phase by heat treatment described below. If X representing the Cu content is less than the above range, it will be difficult to form a microcrystalline phase, and if it exceeds the above range, it will be difficult to form the molten alloy into a thin ribbon during rapid cooling. Furthermore, if X is outside the above range, the magnetic properties, particularly the magnetic permeability, will decrease, and, for example, when applied to a wound core for a common mode jog, good effective magnetic permeability will not be obtained.

Note that preferably 0.3≦x≦2.

Si and B are contained to make the alloy amorphous. In the present invention, an amorphous alloy is produced by rapidly cooling a molten alloy having the composition represented by the above formula using a single roll method or the like, or by rapidly cooling using a water atomization method, and then heat-treated to produce a finely divided alloy. In order to form a crystalline phase, Si and B need to be contained within the above ranges.

When y representing the Si content, Z representing the B content, and y+z are outside the above ranges, it becomes difficult to make the alloy amorphous. Moreover, if B exceeds the above range, magnetostriction will increase.

Preferably, 8≦y≦20.6≦z≦16, particularly 7≦z≦16.20≦y+z≦28.

In addition to Si and B, C1Ge, P,
One or more elements selected from Ga, Sb, In, Be, and As may be contained. These vitrifying elements, together with Sl and B, have the effect of promoting amorphization, and also have the effect of adjusting the Curie temperature and magnetostriction. These vitrifying elements are preferably contained so as to replace 30% or less of the total content of Si and B, that is, y+z.

Among these, P is particularly preferred as an element that improves corrosion resistance and promotes amorphization.

Cr and Ml are contained in order to reduce magnetostriction and improve corrosion resistance.

In addition, Ml is used during the heat treatment for crystallization described below.
It also has the effect of widening the suitable range of processing temperatures. If p and q, which represent the contents of Cr and Ml, respectively, are less than the above ranges, it will be difficult to form a microcrystalline phase, and sufficient low magnetostriction and corrosion resistance will not be obtained. Also, p and q
If it exceeds the above range, it becomes difficult to make it amorphous, and
Saturation magnetic flux density decreases. To explain p and q in detail, if 05≦p and 0.5≦q, then the magnetostriction constant λs can be adjusted by ±5X.
Can be within 10-6, 0.5≦p and 1.0
If ≦q, the magnetostriction constant λs can be set to +4X10-' or less, and if 10≦p or 1.0≦q, the magnetostriction constant S can be set to +3X10-' or less.

Further, under the conditions of 0.5≦p and 0.5≦q, 3≦p or 2≦q, preferably 3.5≦p or 2.
By setting 5≦q, the magnetostriction constant ^S becomes +〇, 5X1
It can be 0-6 or less. Further, in this case, when a thin plate is used, an effective magnetic permeability of 5,000 or more can be obtained at 100 kHz, and an effective magnetic permeability of 10,000 or more, even as high as 20,000, can be obtained in some cases. Furthermore, in this case, a saturation magnetic flux density of 10 kG or more can be obtained.

Note that it is preferable that p→−q≦15.

In addition to the elements listed below, the soft magnetic alloys of the present invention
ff, platinum group element, S c , Y , frllJJ
i element, 1 selected from Au, Zn, Sn and Re
More than one type of element may be contained.

If these elements are contained, the total content is
It is preferable that the amount is 10% or less based on the composition represented by the following formula.

The present invention also includes a soft magnetic alloy having a microcrystalline phase and having a composition represented by the following formula (II).

[Formula (II)] (Fe l -aNla) + oo-y-y-1-p
-qcllxsl, y13zcr pM' 6M2r However, in the above formula (II), Ml is ■ and/or Mn, and M has l:, T i , Z r, +(f
, N+), Ta, Mo, and W, and 0≦a≦0.5. 01≦x≦5. 0≦y≦20. 6≦z≦20. 15≦, y+Z≦30, 0, 5≦p≦10. 0, 5≦q≦10゜O≦ “≦10.

The soft magnetic alloy having the composition represented by the above formula (II) is a Fe-Cu-3i-B-M2 alloy containing Cr and M.
By adding l, magnetostriction is lowered and corrosion resistance is improved.

In the soft magnetic alloy having the composition represented by the above formula (II), the reasons for limiting the ranges of a, The elements that may be used are the same as those for the soft magnetic alloy represented by the above formula (I).

In addition, in the above formula (II), it is preferable that p+q+r≦15.

The soft magnetic alloy of the present invention has a microcrystalline phase of 50%.
The above is preferable, and when the entire soft magnetic alloy is composed of a microcrystalline phase, particularly high magnetic properties can be obtained.

Note that the portion of the soft magnetic alloy other than the microcrystalline phase is substantially amorphous.

In order to obtain good magnetic properties in the present invention, the average grain size of the microcrystals is preferably 1000 Å or less, more preferably 500 Å or less, even more preferably 200 Å or less, and particularly preferably 50 to 200 particles. The average grain size in this case is the average of the maximum diameters of each crystal grain. The average particle size can be measured using a transmission electron microscope.

Note that the soft magnetic alloy of the present invention may contain inevitable impurities such as N, 0, and S, as long as they do not adversely affect the magnetic properties.

Next, a method for manufacturing the soft magnetic alloy will be explained.

The above-mentioned soft magnetic alloy is produced by heat-treating amorphous alloy ribbon produced by a normal liquid quenching method such as a single-roll method or a twin-roll method, or an amorphous alloy powder produced by a water atomization method. It is obtained by forming a microcrystalline phase.

The thickness of the amorphous alloy ribbon produced by the liquid quenching method is preferably 5 to 50 μm, particularly 15 to 25 μm.

It is difficult to manufacture an amorphous alloy ribbon whose thickness falls outside the range described in 1.

The heat treatment applied to the alloy ribbon or alloy powder produced by the liquid quenching method or the water atomization method is preferably carried out in vacuum or in an inert gas atmosphere such as nitrogen, hydrogen, or Ar. You may do so.

The heat treatment temperature and time depend on the composition of the alloy being heat treated,
450 to 700℃, although it varies depending on the shape and dimensions etc.
It is preferable that the time is 5 minutes to 24 hours.

According to the present invention, good magnetic properties, particularly high magnetic permeability, can be obtained over almost the entire temperature range.

If the heat treatment temperature is less than the above range, it will be difficult to form a microcrystalline phase, and if it exceeds the above range, the crystal grains will become coarse, making it impossible to obtain a soft magnetic powder with high magnetic properties.

If the heat treatment time is less than the above range, it will be difficult to perform uniform heating, and if it exceeds the above range, the crystal grains will become coarse, making it impossible to obtain a soft magnetic alloy with high magnetic properties.

In addition, the more preferable heat treatment temperature and heat treatment time are 4.
50-650°C, especially 500-600''C for 5 minutes to 6 hours.

Note that this heat treatment may be performed in a magnetic field.

Next, the six-pull shield shrine and powder core of the present invention will be explained in detail.

A magnetic shielding material to which the soft magnetic alloy of the present invention is applied contains soft magnetic powder obtained by pulverizing the soft magnetic alloy of the present invention and a binder.

This soft magnetic powder is preferably composed of flat particles.

The average thickness of the flat particles is preferably 1 μm or less, particularly 001 to 1 μm. When the average thickness is less than 0.01 yA, the dispersibility in the binder decreases. In addition, magnetic properties such as magnetic permeability deteriorate, and shielding properties become insufficient.

On the other hand, if the number of houses exceeds one, it will not be possible to form a coating film in which flat particles are evenly dispersed when applying a thin layer of magnetic shielding material, and the presence of flat particles in the thickness direction of the coating film will not be possible. As the number decreases, the shielding characteristics become insufficient. In addition, when the average thickness is 0.01 to 0.6-, more preferable results are obtained.

The average thickness may be measured using an analytical scanning electron microscope.

The average aspect ratio of the flat particles is preferably from 10 to 3,000, particularly from 10 to 500. In the present invention, the average aspect ratio is a value obtained by dividing the average particle diameter of flat particles by their average thickness.

When the average aspect ratio is less than 10, the influence of the demagnetizing field becomes large, magnetic properties such as magnetic permeability decrease, and shielding properties become insufficient.

On the other hand, if the average aspect ratio of flat grains having an average thickness within the above range exceeds 3000, the average grain size will become too large, making it easy to break when cross-wired with the binder, resulting in deterioration of magnetic properties. do.

In addition, the average particle size in this case means the weight average particle size Dao, which is integrated from the smaller weight particle size of the flat particles constituting the soft magnetic powder, and this value is the weight of the entire soft magnetic powder. This is the particle size of the flat particles when the particle size reaches 50%. In addition, the particle size in this case is the particle size measured with a particle size analyzer using a light scattering method. More specifically, particle size analysis using a light scattering method is a method of measuring the particle size distribution by measuring the scattering angle of Frampeau core diffraction or Miy scattering using a laser beam, halogen lamp, etc. as a light source while circulating the sample. It is.

For details, see, for example, "Powder and Industry J VOL," 9 No.
, 7 (19g?). D above
s.

can be determined from the particle size distribution obtained by such a particle size analyzer.

For flat particles, D so determined in this way is
It is preferable that it is 5-30+a+.

In the main surface shape of such a flat particle, when the length of the major axis (maximum diameter) is a and the length (minimum diameter) of the minor axis is b, the average axial ratio a / b is the magnetic When directionality is required for the shield, a value as large as possible of 1.2 or more is desirable.

When the magnetic field source has directionality, by curing the magnetic paint while applying an orienting magnetic field in that direction, the magnetic permeability in that direction can be improved and the magnetic shielding effect can be increased. In this case, when a/b is 1.2 to 5, more preferable results are obtained. According to the media stirring mill described below, such an axial ratio can be easily achieved.

The long axis and short axis of the particles may be measured using an analytical transmission electron microscope.

The soft magnetic powder made of such flat particles preferably has the following magnetic properties in order to improve magnetic shielding properties.

The maximum magnetic permeability JL m in a DC magnetic field is 20 to 80, more preferably 25 to 60, and the coercive force Hc is 1 to 200.
e, more preferably 1 to 140e.

The magnetic properties, especially the coercive force, of the soft magnetic powder made of such flat particles are 1. OO
It is normal for the seat to be up to 1000 times higher.

The soft magnetic powder as described above is preferably manufactured by the following manufacturing method.

This production method consists of a first method in which an amorphous alloy powder is produced by rapidly cooling a molten alloy having a composition represented by the following formula:
a second step of obtaining an amorphous alloy powder composed of flat amorphous alloy particles, and a third step of subjecting the obtained flat amorphous alloy powder to a heat treatment to form a microcrystalline phase.

In the first step, it is preferable to use a water atomization method for high-speed quenching. In this specification, the amorphous alloy powder obtained by the water atomization method is referred to as water atomized powder.

FIG. 2 is a schematic diagram illustrating the water atomization method.

The raw material alloy is made into a molten metal by induction heating or the like, and is flowed down into the spray tank 2 from a nozzle at the bottom of the melting furnace 1. High-pressure water is injected from the spray nozzle 3 onto the flowing down molten alloy to cool it and solidify it into powder. Note that, in order to prevent oxidation of the powder, it is preferable that the interior of the spray tank 2 be an inert gas atmosphere. Next, the powder is collected from the spray tank 2 and the drainage tank 5 and dried to obtain water atomized powder.

When such a water atomization method is used, the molten alloy is directly granulated without forming it into a ribbon shape.

In such a water atomization method, the amount of flowing molten metal, the pressurizing pressure of high-pressure water from the spray nozzle, the amount of injection, the injection speed,
By appropriately controlling and adjusting the spray direction, the shape of the spray nozzle, etc., water atomized powder having the bulk density and dimensions described below can be obtained. Preferred examples of these various conditions for the water atomization method are shown below.

The flow rate of /8 hot water is preferably about 10 to 1000 g/s.

It is preferable that the pressurized pressure of the high-pressure water from the spray nozzle is about 10 to 1000 atm, and the injection amount is about 50 to 1.00 j/sec.

Note that the preferable cooling rate is about 10<2 >to 10''' C/s.

Further, the composition of the raw material alloy may be the composition of the desired soft magnetic powder, and specifically, it is selected from the compositions represented by the above formula.

In order to obtain the soft magnetic powder as described above, it is preferable that the weight average particle diameter D5 of the amorphous alloy particles constituting the water atomized powder is 5 to 30 degrees, particularly 7 to 20 degrees. If it is less than this range, flattening becomes difficult, and if it exceeds this range, the degree of amorphization decreases.

In addition, the water atomized powder has a bulk density of 2 g/cm3 or more, particularly 2.1 to 5 g/cm3, more preferably 2.5 to 4 g/cm3,
It is preferable that it is 5 g/cm3.

Note that the bulk density and the regularity of the alloy particle shape are correlated.
Specifically, when the bulk density is low, the irregularity of the particle shape is high, and when the bulk density is high, the irregularity of the particle shape is low. Since water atomized powder having a bulk density exceeding the above range has a low degree of amorphization, it is difficult to achieve the degree of amorphization described below even if it is flattened using a media stirring mill. In addition, since the water atomized powder whose bulk density is less than the above range has high irregularity in the shape of the alloy particles, irregular fractures of the alloy particles occur when flattened by a media stirring mill, resulting in the above-mentioned dimensions and It is difficult to form flat particles with a specific shape and particle size distribution.

In water atomized powder whose bulk density is within the range listed in 1, the alloy particles are almost spherical, so when flattening is performed by a medium stirring mill in the second step, the rolling and shearing action of the medium stirring mill is effective. Therefore, flat particles having the shape and dimensions as described above can be easily obtained.

In addition, in order to obtain the above-mentioned soft magnetic powder, a thin ribbon is produced not only by such water atomization method but also by a high-speed cooling method such as an ordinary single roll method, and after coarsely pulverizing the thin ribbon. Flat amorphous alloy particles may be obtained by flattening using a media stirring mill.

The flattening of the amorphous alloy particles in the second step is
Preferably, it is carried out in a media-stirred mill.

The medium stirring mill is an agitator also called a bottle-type mill, bead mill, or agitator ball mill, and is described in, for example, Japanese Patent Laid-Open No. 61-259739.

FIG. 3 is a partial vertical sectional view showing the structure of the media stirring mill.

The medium stirring mill 11 has a large number of rods 14 installed on the inner circumferential side of a cylindrical container 12 and on the outer circumferential side of a rotating body 13 installed in the cylindrical container 12. Beads and a substance to be stirred are filled as a medium between the outer circumferential surfaces of the rotating body 13.

By rotating the cylindrical container 12 and the rotating body 13 at a relatively high speed, the rod 14 stirs the beads, and the object to be stirred is mainly rolled and sheared by the beads.

The amorphous alloy particles that make up the water atomized powder are
It is flattened by the rolling and shearing action of such a media stirring mill, and a flattened shape suitable for the magnetic shielding material as described above is obtained.

Preferred conditions for rolling and shearing using a media stirring mill include, for example, a bead diameter of 1 to 5 mT! 1, a bead filling rate of 20 to 80%, and a circumferential speed of about 1 to 20 m/s at the tip of the rod 14 provided on the outer peripheral side of the rotating body 13.

Note that it is not possible to obtain flat alloy powder in the shape described above by means other than a media stirring mill, such as a stamp mill, a vibration mill, an attritor, etc.

The flat alloy particles, which have been made into a predetermined shape and size by the medium stirring mill, are subjected to heat treatment in the third step. By this heat treatment, the above-mentioned microcrystalline phase is formed in the flat alloy particles.

This heat treatment is performed in the same manner as the heat treatment described above.

The magnetic shielding material containing soft magnetic powder and a binder obtained in this way has flat particles constituting the soft magnetic powder dispersed in the binder.

Such magnetic shielding materials have a maximum magnetic permeability μ in a DC magnetic field when converted to 100% of the material.

50 or more, preferably ], O0 or more, especially 150 or more
400, or even 1.80 to 350,
The coercive force Hc can be between 2 and 200e, particularly between 2 and 150e.

Such magnetic properties can be easily obtained because the number of processing steps such as pulverization is small and the introduced processing strain is reduced. For this reason, a large 71 is obtained, and a sufficient magnetic shielding effect is obtained. Further, Hc is 200e or less, and in this respect as well, a sufficient magnetic shielding effect can be obtained.

In addition, the filling rate in the magnetic shielding material of soft magnetic powder is 60
It is preferably 95 wt%.

When the filling rate is less than 60 wt%, the magnetic shielding effect decreases rapidly, and when it exceeds 95 wt%, the soft magnetic powder cannot be firmly bound by the binder, and the strength of the magnetic shielding material decreases. do.

When the filling rate is 70 to 90 wt%, a particularly good magnetic shielding effect can be obtained, and the strength of the shielding material is also sufficient.

There are no particular restrictions on the binder used, and known thermoplastic resins,
It can be appropriately selected from thermosetting resins, radiation curable resins, and the like.

In addition, the magnetic shielding material may contain a hardening agent, a dispersant, a stabilizer, a coupling agent, etc. in addition to the soft magnetic powder and the binder.

Such magnetic shielding materials are usually molded into a desired shape or made into a coating composition using a necessary solvent, and then applied, and then, if necessary, heated and cured before use.

In addition, curing is generally performed at 50 to 80° in a heated oven.
What is necessary is just to heat at C for about 6 to 100 hours.

When the magnetic shielding material is formed into a film shape or a thin strip shape and used for magnetic shielding, the thickness of the magnetic shielding material is 5 to 5.
Preferably, it is 200 μm.

This thickness range is chosen because the first magnetic shielding material to which the present invention is applied has the above-mentioned magnetic properties, and therefore exhibits a high magnetic shielding effect even with a thickness of 5 μm. When shielding from a magnetic field strong enough to prevent magnetic saturation, the magnetic shielding effect does not improve significantly even if the thickness exceeds 200 μm;
This is because it is advantageous in terms of cost if it is less than Im.

In addition, when forming or coating the magnetic shielding material into a desired shape, it is possible to make the magnetic shielding material highly directional by applying an orienting magnetic field or mechanically orienting it. When formed in the form of a plate or film, it exhibits a high magnetic shielding effect against a magnetic field in a direction parallel to the film surface, and exhibits a sufficient effect within the above thickness range.

Note that when applied to a magnetic shield material, a conductive film of Cu, Ni, etc. may be formed on the soft magnetic powder.

Such a magnetic shielding material can be applied to an extremely wide range of applications in addition to magnetic shielding of speakers, CRTs, and the like.

[Powder core] The powder core to which the present invention is applied contains powder of the first soft magnetic alloy represented by the above formula.

The shape and dimensions of the dust core are similar to those of the wound core described above.

Although there are no particular limitations on the method for producing such a powder core, it is preferable to produce it by the method described below.

First, a molten alloy having a composition represented by the above formula is rapidly quenched by a liquid quenching method to obtain an amorphous alloy ribbon.

Next, this amorphous alloy ribbon is subjected to heat treatment for embrittlement. This heat treatment is preferably carried out at about 300 to 450°C for about 10 minutes to 10 hours.

After embrittlement heat treatment, 50 to 300
Grind to an average particle size of about 0.

The obtained amorphous alloy particles are subjected to insulation treatment. Although there are no particular limitations on the insulation treatment method, it is preferable to perform insulation by forming a coating of an inorganic material such as water glass on the particle surface.

Note that an insulating film can also be formed in the same manner as the above-described wound core by performing heat treatment for embrittlement in an oxidizing atmosphere. In this case, an insulation treatment as described above may be further performed.

The insulated amorphous alloy particles are press-molded. When press-molding, various inorganic lubricants and/or organic lubricants may be added as necessary.

The temperature during pressing is about 400~550''C, the applied pressure is about 5~20t/cm2, and the pressure holding time is about 1 second~
It takes about 1 hour.

After press molding, heat treatment is performed under the conditions described above to form a microcrystalline phase in the amorphous alloy particles, thereby obtaining a powder core containing the soft magnetic alloy powder of the present invention. The space factor of the powder in the magnetic core is approximately 50 to 100%, preferably 75 to 95%.

[2] Wound magnetic core and powder powder of the present invention obtained in this way]
It is suitable for output smoothing choke coils for switching power supplies.

<Examples> Hereinafter, the present invention will be explained in more detail by giving specific examples and experimental examples.

[Experimental Example 1] A raw material alloy molten metal having the composition shown in Table 1 below was rapidly cooled by a single roll method to produce an amorphous alloy ribbon.

These amorphous alloy ribbons were heated at 500° C. in N2 gas.
A heat treatment was performed at ~550°C for 1 hour to form a microcrystalline phase, and a soft magnetic ribbon sample was obtained. The thickness of these soft magnetic ribbon samples was 22 μm and the width was 3 mm. In addition, as a result of observing these samples with a transmission electron microscope, they had a microcrystalline phase consisting of crystal grains with an average grain size of 1.000 Å or less.

For samples such as +1, the magnetostriction constant Is was measured, the corrosion resistance was evaluated, and the rate of change in coercive force Hc due to stress application was measured.

Corrosion resistance was evaluated by the following criteria on the surface condition of each sample after immersing it in 5% saline for 24 hours.

○・No change △: Partially rusted X: Large rusting area XX Rust on the entire surface The rate of change in coercive force Hc was measured as follows.

Each of the ribbon samples described above was wound into a toroidal shape having an outer diameter of 14 mm, an inner diameter of 10 mm, and a height of 3 myl, and the terminal end was fixed to form a wound core. The coercive force Hco of this wound core was measured.

Next, a weight of 500 g was placed on these wound magnetic cores to apply stress, and the coercive force Hc+ of the wound magnetic cores at this time was measured. The rate of change in coercive force shown in Table 1 is Hc+/Hcn.

From the results shown in Table 1, it is clear that the soft magnetic alloy of the present invention containing Cr and ■ has a small magnetostriction constant S and good corrosion resistance.

Note that when a molten alloy having the composition shown below was rapidly cooled by a single roll method, it did not become amorphous nor did it form into a ribbon. Further, when the coercive force of an alloy having the following composition after quenching was subjected to the same heat treatment as above and the coercive force was measured, it was found that the coercive force exceeded 50e.

Cuo, 5Cr4VsSi2oB4Febaj.

Cu+NbaS12oB4F13baj [Experimental Example 2] A soft magnetic ribbon sample was obtained in the same manner as in Experimental Example 1 using a molten alloy having the composition shown in Table 2 below.

As a result of observing these samples using a transmission electron microscope, they were found to have a microcrystalline phase consisting of crystal grains with an average grain size of 1000 Å or less.

The same measurements and evaluations as in Example 1 were performed on these samples.

The results are shown in Table 2.

From the results shown in Table 2, it is clear that low magnetostriction and high corrosion resistance are achieved only by containing both Cr and ■, and such characteristics cannot be obtained by containing only Nb or Nb and Cr. Gao) Karu.

Note that when a molten alloy having the composition shown below was rapidly cooled by a single roll method, it did not become amorphous and did not form a thin ribbon. Further, when the coercive force of an alloy having the following composition after quenching was subjected to the same heat treatment as above and the coercive force was measured, it was found that the coercive force exceeded 50e.

CL1+Nb5Cr3Si2o, JaFebaj [Experimental Example 3] A soft magnetic ribbon sample was obtained in the same manner as in Experimental Example 1 using a molten alloy having the composition shown in Table 3.

As a result of observing these samples using a transmission electron microscope, they were found to have a microcrystalline phase consisting of crystal grains with an average grain size of 1000 Å or less.

The same measurements and evaluations as in Experimental Example 1 were performed on these samples.

The results are shown in Table 3.

In addition, when an amorphous alloy ribbon obtained by rapidly cooling a molten alloy having the following composition by a single roll method was subjected to the same heat treatment as in Experimental Example 1, a microcrystalline phase consisting of crystal grains with an average grain size of 1000 Å or less was obtained. was not observed, and the coercive force was 5
It exceeded 0e.

C11o, yV<Sil 3. J9F+3baj
.

C; uo, tcrisi l *, 5BeFeba
j.

This result shows that it is necessary to contain both Cr and ■ in order to form microcrystals.

[Experimental Example 4] CLIQ, 5CrpV, Si I 3. gBeFe
baj, magnetostriction constant λs, effective magnetic permeability μ, and saturation magnetic flux density Bs of the alloy ribbon were measured. Note that the effective magnetic permeability was measured at a measurement frequency of 100 kHz and a measurement magnetic field of 2 mOe.

The results are shown in Figure 1.

From the results shown in FIG. 1, it is clear that the soft magnetic alloy of the present invention has low magnetostriction and good magnetic properties.

In addition, when a soft magnetic alloy having a composition in which Nb was further added to the alloy composition containing Cr and ■ of each of the above examples was made and the same measurements as in the above experimental examples were performed, almost the same results as above were obtained. was gotten.

[Example 1] The amorphous alloy ribbon used in the production of Sample No. 3 of Experimental Example 1 was embrittled by heat treatment at 350°C for 1 hour, and then reduced to a grain size of 105 to 50 by a vibrating ball mill.
It was ground to a size in the range of o and m. A water glass coating was formed on the obtained powder, and an applied pressure of 1. Ot /
It was pressed at 480° C. for 1 minute at kg/cm 2 . Furthermore, the same heat treatment as in Example 1 was performed, and the outer diameter was 14+ nm.
A powder core having an inner diameter of 1.0 mm and a height of 3+no+ was obtained.

The space factor of the amorphous alloy powder in this powder core is 9
It was 1vo1%.

A gap with a gap length of 0.8 mm was formed in this powder core, and the powder core was placed in a casing and wound. When this was used as a smooth choke coil for a switching power supply,
No groaning was observed at the gap forming part.

In addition, 1 kl of this powder core (magnetic permeability at z 0 55
It was 0.

Further, as a result of observing the alloy powder contained in this powder core using a transmission electron microscope, it was found that it had a microcrystalline phase consisting of crystal grains with an average grain size of 1000 Å or less.

[Example 2] Water atomized powder was obtained using a water atomization device as shown in FIG. As for the composition of the raw material alloy, those of Zamble No. 3 of Experimental Example 1 were used.

The water atomized powder was then flattened using a media stirring mill as shown in FIG. Next, the flattened water atomized powder was subjected to the same heat treatment as in Example 1. As a result of observing the water atomized powder after the heat treatment using a transmission electron microscope, it was found that it had a microcrystalline phase consisting of crystal grains with an average grain size of 1000 Å or less. D so of water atomized powder
is 12 μm, the average thickness is 01 mm, and a/b is:
It was 14.

Note that the average thickness was measured using an analytical scanning electron microscope, and Dso was measured using a precision analyzer using light scattering.

Next, the obtained soft magnetic powder was mixed with the following binder, curing agent, and solvent to produce a magnetic shielding material.

(Binder) Vinyl chloride-vinyl acetate copolymer [S-LEC A (manufactured by Block Chemical Co., Ltd.)] 1100 parts by weight Riurethane [Niraporan 2304 (manufactured by Nippon Polyurethane Co., Ltd.) 100 parts by weight (solid content equivalent) (Curing agent) Polyisocyanate [Coronate HL (manufactured by Nippon Polyurethane Co., Ltd.) 1 10 parts by weight (solvent) MEK 850 parts by weight The filling rate of the soft magnetic powder in the magnetic shielding material was 80 wt%.

The obtained magnetic shield material was made into a long P I with a thickness of 75 μm.
The binder was applied to F and T substrates to a thickness of 100 mm, wound up into a roll, and then heated at 60° C. for 60 minutes to harden the binder. Next, the magnetic shielding material was cut into sheets to obtain shield plates.

Measure the shield ratio of this shield plate.

The shield ratio is determined by placing a shield plate on a magnet, measuring the leakage magnetic flux φ at a position 0.5 cm from the shield plate, and calculating the magnetic flux φ when there is no shield plate. The ratio φ/
φ. It was expressed as

Note that during the measurement, the shield plate was bent to a radius of curvature of 70 mm and stress was applied.

The shield ratio of this shield plate was 0.02 or less.

Furthermore, when the coercive force of the magnetic shielding material was measured before and after the binder was cured, no difference was found between them.

The effects of the present invention are clear from the above examples.

<Effects of the Invention> In the present invention, a soft magnetic alloy with low magnetostriction and high corrosion resistance is realized by a new composition containing Cr, (1) and/or Mn.

[Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between the contents of Cr and ■ in the soft magnetic alloy composition of the present invention, the magnetostriction constant λs, the saturation magnetic flux density Bs, and the effective magnetic permeability μ. FIG. 2 is a schematic diagram for explaining the water atomization method. FIG. 3 is a partial vertical sectional view showing the structure of the media stirring mill. Explanation of phase numbers]...Melting furnace 2...Spray tank 3...Spray nozzle 4...Water 5...Water extraction tank 11...Medium stirring mill 12...Cylindrical container 13... [Rotating body] 4...Rod Patent applicant: TDA-K Co., Ltd. Agent: Patent attorney: Yodo Ishii, Patent attorney:
Increase 1) Tatsuya F Eng G- F Eng G-

Claims (1)

[Scope of Claims] (1) A magnetic shielding material characterized by containing powder of a soft magnetic alloy having a microcrystalline phase and having a composition represented by the following formula (I), and a binder. [Formula (I)] (Fe_1_−_aNi_a)_1_0_0_−_x_
−_y_-_z_-_p_-_qCu_xSi_yB_
zCr_pM^1_q (However, in the above formula (I), M^1 is V and/or Mn, 0≦a≦0.5, 0.1≦x≦5, 6≦y≦20, 6≦z≦ (20) (2) The magnetostriction constant λs is within ±5×10^-^6. magnetic shielding material. (3) A magnetic shielding material characterized by containing powder of a soft magnetic alloy having a microcrystalline phase and having a composition represented by the following formula (II), and a binder. [Formula (II)] (Fe_1_−_aNi_a)_1_0_0_−_x_
−_y_-_z_-_p_-_qCu_xSi_yB_
zCr_pM^1_qM^2_r (however, the above formula (II)
, M^1 is V and/or Mn, and M^2
is one or more elements selected from Ti, Zr, Hf, Nb, Ta, Mo and W, 0≦a≦0.5, 0.1≦x≦5, 0≦y≦20, 6≦ z≦20, 15≦y+z≦30, 0.5≦p≦10, 0.5≦q≦10, 0≦r≦10. ) (4) The magnetic shielding material according to claim 3, wherein the magnetostriction constant λs is within ±5×10^-^6. (5) A powder core characterized in that it is formed from a soft magnetic alloy powder having a microcrystalline phase and having a composition represented by the following formula (I). [Formula (I)] (Fe_1_−_aNi_a)_1_0_0_−_x_
−_y_-_z_-_p_-_qCu_xSi_yB_
zCr_pM^1_q (However, in the above formula (I), M^1 is V and/or Mn, 0≦a≦0.5, 0.1≦x≦5, 6≦y≦20, 6≦z≦ (6) The magnetostriction constant λs is within ±5×10^-^6. powder core. (7) A powder core formed from a soft magnetic alloy powder having a microcrystalline phase and having a composition represented by the following formula (II). [Formula (II)] (Fe_1_−_aNi_a)_1_0_0_−_x_
−_y_-_z_-_p_-_qCu_xSi_yB_
zCr_pM^1_qM^2_r (however, the above formula (II)
, M^1 is V and/or Mn, and M^2
is one or more elements selected from Ti, Zr, Hf, Nb, Ta, Mo and W, 0≦a≦0.5, 0.1≦x≦5, 0≦y≦20, 6≦ z≦20, 15≦y+z≦30, 0.5≦p≦10, 0.5≦q≦10, 0≦r≦10. ) (8) The powder core according to claim 7, wherein the magnetostriction constant λs is within ±5×10^-^6.