JPH0375342A - Soft magnetic alloy and its manufacture - Google Patents

Abstract

PURPOSE:To manufacture the soft magnetic alloy having high corrosion resistance and low magnetostriction by subjecting an amorphous alloy constituted of specified ratios of Fe, Ni, Cu, Si, B, Cr, V and Mn to heat treatment and preparing a soft magnetic alloy contg. a microcrystalline phase. CONSTITUTION:An amorphous alloy expressed by a formula of, by atomic ratio, (Fe1-aNia)100-x-y-z-p-q-rCuxSiyBzCrpVqMnr (where 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<=2.5, 0<=r and 3<=p+q+r<=12.5 are regulated) and manufactured by an ordinary liquisol quenching method is subjected to heat treatment at about 400 to 700 deg.C for about 5min to 24hr to prepare a soft magnetic alloy contg. 0.1 to 95% microcrystals of about <=1000Angstrom average grain size. In this way, the soft magnetic alloy having + or -5X10<-6> magnetostriction constant, about >=5000 effective magnetic permeability in 100kHz and about >=10KG saturation magnetic flux density can be obtd., which is suitable for a magnetic shielding material or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a soft magnetic alloy, particularly a highly corrosion resistant and low magnetostrictive Fe-based magnetomagnetic alloy, and a method for producing the same.

<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.

(L) The magnetostriction constant Ls is small (LeS=±5XIO−
).

(2) Small magnetocrystalline anisotropy.

Unless these two required properties are satisfied, the soft magnetic material will not have sufficient basic properties or cannot be used at all depending on the application.

To be more specific, applications where stress is constantly applied during use of magnetic heads, etc., or the manufacturing process of the core itself such as powder cores,
Alternatively, in applications where stress is constantly applied to the core itself, the magnetostriction constant is Ls=O~-5X
10-' is an essential condition.

Pure iron, silicon steel, sendust alloy, amorphous alloy, etc. are known as Fe-based alloy soft magnetic materials, 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 uses have been limited. In particular, applications that are subject to stress, such as magnetic heads, smooth choke coils, powder cores, and magnetic shields, have the fundamental problem of significantly degrading magnetic properties, so expansion of applications is not progressing. There is no situation.

On the other hand, among amorphous alloys, there are alloys whose magnetostriction constant is close to 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 where the cost of materials for magnetic heads and the like is not much of 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 in applications where stress is applied, such as magnetic heads.

The above publication describes an example in which the magnetostriction constant becomes almost zero when the boron B content is around 5% (for example,
F ey4Cul N b* S i l? B6 alloy)
However, it is widely known in boat fishing 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, is extremely low.

Incidentally, an alloy having a microcrystalline phase is manufactured by subjecting an amorphous alloy to heat treatment as described above, and an amorphous alloy is manufactured by a liquid quenching method such as a single roll method or a twin roll method. The single roll method and double roll method are
This is a method in which molten alloy is injected from a nozzle and collided with the surface of a cooling roll to rapidly cool it and obtain a ribbon or flake of amorphous alloy. The high-speed quenching is preferably performed in a non-oxidizing atmosphere to prevent oxidation of the molten alloy.

However, it is very difficult to create a strictly non-oxidizing atmosphere, and the manufacturing cost also increases. Therefore, the atmosphere, particularly during rapid cooling, usually contains some oxygen, which oxidizes the molten alloy near the nozzle tip. The molten alloy oxidizes, and the matter becomes scale and accumulates at the tip of the nozzle, so if you continue to inject the molten alloy, the nozzle will become clogged and even destroyed, requiring nozzle replacement or causing damage to the equipment itself. Sometimes.

Such nozzle clogging becomes a particular problem during mass production in which molten alloy injection is performed continuously for a long period of time.

Further, when the viscosity of the molten alloy is high, injection becomes difficult due to the reduction in the nozzle diameter due to the oxide, and nozzle clogging is accelerated.

This clogging of the nozzle reduces mass productivity and increases costs.

The present invention has been made in view of the above-mentioned circumstances, and provides a soft magnetic alloy having a microcrystalline phase, which has significantly improved corrosion resistance, and has an extremely small magnetostriction constant, especially a soft magnetic alloy with a magnetostriction constant of approximately It is an object of the present invention to provide a soft magnetic alloy that is close to zero or exists in a negative range from zero, that can be mass-produced at low cost, and a method for manufacturing the same.

Means for Solving the Problems> Such objects are achieved by the present invention as described in (1) to (5) below.

(1) A soft magnetic alloy having a microcrystalline phase and having a composition represented by the following formula (I) in terms of atomic ratio.

[Formula (I)] (Fe l -aNI J I Go -X -11-
1-p-Q -rcuJ1yBxcf'pVqMnr(
However, in the above formula (I), O≦a≦0.5, O3l≦X≦5. 6≦y≦20. 6≦Z≦20. 15≦y1z≦30°0.5≦p≦10 0.5≦q≦2.5 0≦r 3≦p+q+r≦12.5. J (2) The above (
The soft magnetic alloy described in 1).

(3) The above (1) in which the proportion of microcrystalline phase is 0.1 to 95%
) or the soft magnetic alloy described in (2).

(4) A method for producing a soft magnetic alloy, which comprises heat-treating an amorphous alloy having a composition represented by the following formula (I) in atomic ratio to obtain a soft magnetic alloy having a microcrystalline phase.

[Formula (1)] % Formula % (However, in the above formula (I), 05a≦0.5. 0.1≦X≦5. 6≦y≦20. 6≦2≦20゜15≦y+z≦30 (゜0.5≦p≦10 0.5≦q≦2.5 O≦r 3≦p+q+r≦12.5) The method for producing a soft magnetic alloy according to (4) above, which is produced by collision.

Effect〉 The soft magnetic alloy of 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, since Cr and V, or Mn in addition to these are contained in a soft magnetic alloy having a microcrystalline phase, the magnetostriction can be reduced, in particular, the magnetostriction can be made negative from zero, and the corrosion resistance can be significantly improved. This is something that can be improved.

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

The soft magnetic alloy of the present invention is also suitable for various magnetic cores. For example, when applied to gapped magnetic cores, cut cores, etc., no whirring occurs.

Further, when a resin coating is provided when forming a gapped magnetic core, a cut core, etc., the magnetic properties are not deteriorated due to curing shrinkage of the resin, as described above.

Furthermore, since the magnetostriction is small, it is of course suitable for magnetic heads.

The soft magnetic alloy of the present invention has a composition represented by the above formula (I), and in order to suppress the V content to 2.5 at% or less, the molten alloy is injected from a nozzle and rapidly quenched. Oxidation of the molten alloy is prevented, and the viscosity of the molten metal is low. Therefore, by selecting the composition represented by the above formula (I), nozzle clogging can be extremely effectively prevented.

Note that the effect of improving the corrosion resistance of soft magnetic alloys achieved by containing Cr, V, Mn, etc. is due to the effect of a passive film formed on the surface of the soft magnetic alloy, but a passive film is formed in the molten alloy. I can't. For this reason, the present inventors have conducted repeated experiments to improve the oxidation resistance of molten alloys, and have found that ① oxidation resistance can be critically improved by reducing the content to 2.5 at% or less. These findings led to the present invention.

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

The soft magnetic alloy of the present invention has a microcrystalline phase and has a composition represented by the following formula (I) in terms of atomic ratio.

[Formula (I)] (Fed-aNla) too-X-F-! -11-q-
rcu, 1S1yBxcf”pVJnrHowever, the above formula (
In I), O≦a≦0.5. 0.15x≦5. 6≦y≦201 6≦Z≦20. 15≦y+z≦30° 0.5≦p≦10 0.5≦q≦2.5 0≦r 3≦p+q+r≦12.5.

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 a molten alloy into a thin ribbon during rapid cooling. Furthermore, when X is outside the above range, the magnetic properties, particularly the magnetic permeability, decrease, and, for example, when applied to a wound core for a common mode choke, good effective magnetic permeability cannot 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 St 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 SL and B, C1Ge and P% are used as vitrification elements.
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 Mn are contained in order to reduce magnetostriction and improve corrosion resistance. In addition, (2) and Mn also have the effect of widening the range of preferable treatment temperatures during heat treatment for crystallization, which will be described later. p+q+r
If it is less than the above range, not only will it be difficult to form a microcrystalline phase, but also sufficient low magnetostriction and corrosion resistance will not be obtained. Also,
If p+q+r exceeds the above range, it becomes difficult to make the material amorphous, and the saturation magnetic flux density decreases.

By setting q, which represents the content of (2), within the above range, the oxidation resistance of the molten metal is significantly improved, and the viscosity of the molten metal is also reduced. The preferred ranges of p and q%r are 1≦p≦30, 5≦q≦1O≦r≦0. It is 5.

The magnetic properties of the soft magnetic alloy of the present invention are as follows: 100 kHz
An effective magnetic permeability of 5000 or more is obtained at z, and 100
An effective magnetic permeability of 0.00 or more and as high as 20,000 can be easily obtained. Furthermore, a saturation magnetic flux density of 10 kG or more can be easily obtained.

In addition to the elements listed above, the soft magnetic alloy of the present invention also contains Aj
2. Platinum group elements, Sc, Y, rare earth elements, Au, Zn,
One or more elements selected from Sn and Re may be contained.

If these elements are contained, the total content is
It is preferably 10% or less with respect to the composition represented by the above formula.

The soft magnetic alloy of the present invention has a ratio of microcrystalline phase of 0.1
~95%, particularly 50-90% is preferred.
By setting the crystallinity within such a range, a small S can be obtained, and the effective magnetic permeability is improved. The crystallization rate can be controlled by heat treatment conditions.

Note that the crystalline region can be confirmed by a transmission electron micrograph. Further, 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 unavoidable impurities such as N, O, and S, as long as they do not adversely affect the magnetic properties.

The method for manufacturing the soft magnetic alloy of the present invention will be explained below.

The soft magnetic alloy of the present invention is obtained by subjecting an amorphous alloy in the form of a ribbon, flake, or powder to a heat treatment to form a microcrystalline phase.

A high-speed quenching method may be used to produce an amorphous alloy, and a typical liquid quenching method is preferably used, in which molten alloy is injected from a nozzle and quenched at high speed by colliding with the surface of a cooling substrate such as a cooling roll. Alternatively, a water atomization method described later may be used.

Such a liquid quenching method may be a single roll method, a twin roll method, or the like.

In these high-speed quenching methods, nozzle clogging can be prevented by using a molten alloy having a composition represented by the above formula.

In the present invention, there is no particular restriction on the shape of the slit in the injection part of the nozzle used in the liquid quenching method or the injection pressure, but the present invention is suitable for use in nozzles that are prone to clogging, for example, the lip width of the slit in the injection part of the nozzle is 0.1". It is particularly effective for objects with a diameter of about 0.5 mm.

In addition, although quenching is generally performed in the atmosphere, it is preferably performed while blowing an inert gas such as Ar onto at least the nozzle injection part, and more preferably in an inert gas atmosphere such as Ar. It is more preferable to carry out in vacuum.

The thickness of the amorphous alloy ribbon produced by the liquid quenching method is preferably 5 to 50%, particularly 10 to 25%.

It is difficult to manufacture an amorphous alloy ribbon having a thickness outside the above range.

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,
400 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 5.
00 to 650°C for 5 minutes to 6 hours.

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

Preferred application examples of the soft magnetic alloy of the present invention will be described below.

[Wound Core] The wound core to which the present invention is applied is a wound body of the soft magnetic alloy of the present invention.

There are no particular restrictions on the shape and dimensions of the wound core, and the shape may be selected from various shapes such as toroidal or racetrack depending on the purpose, and the dimensions may be, for example, an outer diameter of 3.
~1000mm, inner diameter 2~500mm, height 1
~1100ff1.

In addition, it is preferable that the wound magnetic core is provided with glabellar insulation when pressure resistance is required.

There are no particular restrictions on the interlayer insulation method, and any conventional method may be used, such as interposing an organic film of polyimide or polyester between the eyebrows, or interposing a coated layer of inorganic powder such as alumina or magnesia between the eyebrows.

There are no particular restrictions on the manufacturing method of such a wound magnetic core, but an amorphous alloy ribbon is formed by a liquid quenching method using a molten alloy represented by the above formula, and after this amorphous alloy ribbon is wound, it is finely processed by the heat treatment described above. Preferably, a crystalline phase is formed.

The heat treatment is basically preferably carried out in an inert atmosphere, but it is also possible in an oxidizing atmosphere such as air. In this case, since a thin oxide film is formed on the surface of the ribbon, an interlayer insulation effect is obtained, and especially when applied to a common mode choke core used in a high frequency region, the frequency characteristics are improved.

In order to control the magnetic properties of the magnetic core, it is preferable to perform heat treatment in a magnetic field. By heat-treating the wound core while applying a magnetic field in the magnetic flux direction (the longitudinal direction of the ribbon), a wound core with high square characteristics can be obtained. On the other hand, if heat treatment is performed while applying a magnetic field in a direction perpendicular to the magnetic flux direction of the wound core (width direction of the ribbon), a high permeability wound core having constant magnetic permeability characteristics can be produced.

In addition, when the wound body of the soft magnetic ribbon obtained in this way is used as a cut core or a core with a gap, it is impregnated with a thermosetting resin such as an epoxy resin, and then thermally cured to form a coating.
Cutting or gap formation is then performed.

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

The shape and dimensions of the powder magnetic core include those similar to those of the above-described wound magnetic core, and can be further varied.

Although there are no particular restrictions on the method of manufacturing such a powder magnetic core, it is preferable to manufacture it by the following method.

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, 10 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 to 550℃, and the applied pressure is 5
~20t 7cm" or so, pressure holding time is 0.1 seconds~
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 dust core containing the soft magnetic alloy powder of the present invention. The space factor of the powder in the magnetic core is approximately 50-100%, preferably 75-95%.

The wound magnetic core and powder magnetic core of the present invention thus obtained are suitable for output smoothing coils for switching power supplies and the like.

[RI1-Ki Shielding Material] 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 mm or less, particularly 0.01 to 1 mm. When the average thickness is less than 0.01 pm, 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 it exceeds 1-, 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 particles having an average thickness within the above range exceeds 3000, the average particle size will become too large, which will easily cause breakage when kneaded with a binder, resulting in deterioration of magnetic properties. do.

Note that the average particle size in this case is the weight average particle size. This means the particle size of the flat particles when the weight of the flat particles constituting the soft magnetic powder is integrated from the smallest particle size, and this value reaches 50% of the weight of the entire soft magnetic powder. . Further, the particle size in this case is a particle size measured with a particle size analyzer using a light scattering method. More specifically, particle size analysis using a light scattering method involves measuring the scattering angle of Franhofer diffraction or Miy scattering using a laser beam, halogen lamp, etc. as a light source while circulating the sample to measure the particle size distribution. It is.

The details can be found in, for example, “Powder and Industry J VOL, 19 No.
, 7 (19g?). DI above
I.

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

Flat grains are determined in this way. But 5
It is preferable that it is -30-.

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,
Get more favorable results. 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 μ in a DC magnetic field is 20 to 80, more preferably 25 to 60, and the coercive force Hc is 1 to 200e,
More preferably, it is 1 to 140e.

The magnetic properties, especially the coercive force, of the soft magnetic powder made of flat particles are 100 to
Usually, it is about 1000 times larger.

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

This production method includes a first step of producing an amorphous alloy powder by rapidly cooling a molten alloy having a composition represented by the above formula, a second step of obtaining an amorphous alloy powder composed of flat amorphous alloy particles, and a second step of producing an amorphous alloy powder composed of flat amorphous alloy particles. and a third step of heat-treating the obtained flat amorphous alloy powder 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. 1 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 the molten metal is preferably about 10-1000 g/s.

It is preferable that the pressurized pressure of the high-pressure water from the spray nozzle is about 1° to 1000 atm, and the injection amount is about 50 to 100 I2/sec.

Note that the preferable cooling rate is about 10" to 10'" C/s.

Further, the composition of the raw material alloy may be the composition of the intended 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, the weight average particle size of the amorphous alloy particles constituting the water atomized powder must be determined. is preferably 5 to 30 pi, particularly 7 to 20 pi. If it is less than this range, flattening becomes difficult, and if it exceeds this range, the degree of amorphization decreases.

Further, the water atomized powder preferably has a bulk density of 2 g/cm" or more, particularly 2.1 to 5 g/cm", and more preferably 2.5 to 4.5 g/cm".

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 with a bulk density 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 shapes. and it is difficult to form flat particles with a particle size distribution.

In water atomized powder whose bulk density is within the above range, 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 works effectively, Flat particles having the shape and dimensions 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 a normal 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. 2 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 provided in the cylindrical container 12. Beads as a medium and a substance to be stirred are filled between the outer circumferential side of 13 and the outer circumferential side of the holder 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 mm, a bead filling rate of 20 to 80%, and a peripheral speed at the tip of the rod 14 provided on the outer peripheral side of the rotating body 13. It is about 1 to 20 m/s.

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 manner has flat particles constituting the soft magnetic powder dispersed in the binder.

Such a magnetic shield material has a maximum magnetic permeability μyo in a DC magnetic field of 50 or more, preferably 100 or more, particularly 150 to 400, and even 180 when converted to 100% of the material.
~350, and the coercive force Hc is 2~200e
, especially from 2 to 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. As a result, a large μ can be obtained, and a sufficient magnetic shielding effect can be 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
Preferably it is ~95+vt%.

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.

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 a magnetic shielding material is usually formed 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 in a heating oven at 50 to 80°C.
What is necessary is just to heat it 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 200μ.

This thickness range is set because the magnetic shielding material to which the present invention is applied has the magnetic properties described above.
It shows a high magnetic shielding effect even with a thickness of 5 mm, and when shielding a magnetic field strong enough to prevent magnetic saturation, the magnetic shielding effect will not be noticeable even if it is formed to a thickness of more than 200μ. This is because it is advantageous in terms of cost if the thickness is not improved and is set to 200μ or less.

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.

[Magnetic Head] The magnetic head is suitable for a magnetic head made of laminated thin plates, a thin film magnetic head, a thin film of a metal-in-gap magnetic head, and the like.

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

[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.

Rapid quenching was performed in air. In addition, the nozzle used to inject the molten alloy onto the cooling roll surface had a slit-shaped lip width of 0.5 mm, and the molten alloy was pressurized to 0.2 kgf/cm''' with Ar gas. It was ejected by

For these alloys, the time required for the nozzle to completely close was measured and evaluated based on the following criteria. The results are shown in Table 1 below.
Shown below.

0: 30 minutes or more ○: 10 minutes or more and less than 30 minutes A phase was formed and a soft magnetic ribbon sample was obtained.

The thickness of these soft magnetic ribbon samples is 22μ, and the width is 3
I! It was 1m.

For these samples, the saturation magnetostriction constant λS 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 Δ: Partially rusted ×: Large rusted area XX: Rust on the entire surface The rate of change in coercive force Hc was measured as follows.

Each of the above ribbon samples has an outer diameter of 14 cm, an inner diameter of 1°1, and a height of 3 cm.
It was wound into a toroidal shape of mm, and the terminal end was fixed to form a wound magnetic 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 + / Hc
It is o.

As a result of observation using a transmission electron microscope, the proportion of the microcrystalline phase consisting of crystal grains with an average grain size of 1000 Å or less in the sample of the present invention was 80 to 90%.

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

It is clear that clogging of the nozzle is significantly improved by controlling the content to 2.5 at% or less.

[Example 2] The amorphous alloy ribbon used in the production of Sample No. 3 of 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 range of 0-. A water glass coating was formed on the obtained powder, and an applied pressure of 10 t 7 cm was applied.
2 at 480° C. for 1 minute. Furthermore, Example 1
The same heat treatment as above was applied, and the outer diameter was 14 mm, the inner diameter was 10 mm,
A powder magnetic core with a height of 3 nuo was obtained.

The space factor of the alloy powder in this powder magnetic core was 91vo1%.

When this powder magnetic core was used as a smooth choke coil for a switching power supply, no whirring was observed.

The magnetic permeability of this powder magnetic core at 1 kHz was 350.

Further, as a result of observing the alloy powder contained in this powder magnetic core using a transmission electron microscope, the proportion of the microcrystalline phase consisting of crystal grains with an average grain size of 1000 Å or less was 80 to 90%.

[Example 3] The amorphous alloy ribbons used in the production of samples No. 2 of Example 1 were wound. Furthermore, the same heat treatment as in Example 1 was performed to form a microcrystalline phase, and the outer diameter was 14III11.
A rolled body having an inner diameter of 10 mm and a height of 3 aun was obtained.

The obtained wound body was impregnated with epoxy resin and then thermally cured to obtain a wound magnetic core.

Next, a gap with a gap length of 0.8 mm was formed in this wound core, and further winding was performed. When this was used as a smooth choke coil for a switching power supply, no whirring was observed at the gap forming part.

The magnetic permeability of this wound core at 1 kHz was 250, the coercive force was 0.2'Oe, and the saturation magnetic flux density was 10 kG.

Further, as a result of observing the alloy ribbon constituting this wound magnetic core using a transmission electron microscope, the proportion of the microcrystalline phase consisting of crystal grains with an average grain size of 1000 Å or less was 80 to 90%.

[Example 4] Water atomized powder was obtained using a water atomization device as shown in FIG. The composition of the raw material alloy used was that of sample N003 of Example 1.

The inner diameter of the nozzle at the bottom of the melting furnace 1 of the water atomization device was 2 mm, and the injection pressure was 0.2 kgf/cm. Furthermore, the atmosphere during injection was an Ar gas atmosphere containing less than 1% oxygen. .

When the injection of molten alloy was continued under these conditions, 30
No nozzle blockage was observed for more than a minute.

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, the proportion of the microcrystalline phase consisting of crystal grains with an average grain size of 1000 Å or less was 80 to 90%. D6° of water atomized powder is 12 units, average thickness is 0.1-,
a/b was 1.4.

The average thickness was measured using an analytical scanning electron microscope, and I)so was measured using a particle size 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 Tsukisui Kagaku Co., Ltd.)] 1,100 parts by weight urethane [Niraporan 2304 (manufactured by Nippon Polyurethane Co., Ltd.]) 1,100 parts by weight in terms of solid content) (Curing agent) Polyisocyanate [Coronate HL (manufactured by Nippon Polyurethane Co., Ltd.)] 110 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 shielding material was coated to a thickness of 100μ on a long PET substrate with a thickness of 75μ, and after being wound into a roll,
The binder was cured by heating at 0° C. for 60 minutes. Next, the magnetic shielding material was cut into sheets to obtain shield plates.

The shield ratio of this shield plate was measured.

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

In addition, when measuring, the shield plate has a radius of curvature of 70n+m.
It was bent 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.

[Example 5] Fe5s, 5cuo, 5cri, sL+, os
A molten alloy having an atomic ratio composition of i+s, J14.0 was rapidly cooled by a single roll method to produce an amorphous alloy ribbon.

A wound body of this amorphous alloy ribbon was produced. The shape of this rolled body is an outer diameter of 14 mm, an inner diameter of 8 m+n, and a height of 1
It was made into a toroidal shape of 0 mm.

This wound body was heat-treated at 510° C. for 1 hour in an N2 gas atmosphere to obtain a wound magnetic core. When the ribbon was subjected to X-ray diffraction after the heat treatment, peaks representing crystals were clearly observed. When the structure was observed using a transmission electron microscope to confirm the microcrystalline phase, the ratio of the microcrystalline phase consisting of crystal grains with an average grain size of 1000 Å or less was 80 to 90%.

The effective magnetic permeability μe, which is a basic characteristic when applied to a common mode choke coil for a noise filter, was measured for the obtained wound core, and the measurement frequency was 100kHz.
z, at a measuring magnetic field of 2 mOe, 1te = 19,00
It was 0.

This value is unattainable with conventional Fe-based amorphous alloys, and is a value that cannot be achieved with well-tuned G.

This is a value that can only be obtained with base amorphous alloys.

Moreover, the saturation magnetic flux density Bs of this wound core was 12 kG. This value is about three times that of a CO-based amorphous alloy used for boat fishing.

For comparison, Mn-Zn ferrite core and Fe
Similar measurements were also performed on a wound core using a base amorphous alloy. The measurement results of the wound magnetic core using the above-mentioned alloy of the present invention and the measurement results of these magnetic cores are shown in Table 2 below.

Table 2 B s (kG) μe Invention 12 19.000 Ferrite 4.1 5.500 Amorphous 12 5.500 [Example 6] A soft magnetic alloy ribbon having the composition shown in Table 3 below was prepared according to the above example. The magnetostriction constant S, effective magnetic permeability μe, and saturation magnetic flux density Bs of these alloy ribbons were measured. In addition,
The effective magnetic permeability is measured at a measurement frequency of 100kHz and a measurement magnetic field of 2
It was measured by moe.

The results are shown in Table 3.

As a result of observation using a transmission electron microscope, the proportion of the microcrystalline phase consisting of crystal grains with an average grain size of 1000 Å or less in the sample of the present invention was 80 to 90%.

From the results shown in Table 3, it is clear that the soft magnetic alloy of the present invention has low magnetostriction and good magnetic properties.

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

<Effects of the Invention> In the present invention, in a soft magnetic alloy having a microcrystalline phase, C
By adding r and V and further adding Mn as necessary, a soft magnetic alloy with low magnetostriction and high corrosion resistance is realized, and when producing the raw amorphous alloy, there is no blockage of the nozzle that injects the molten alloy. Since this prevents high mass productivity and low cost, it is possible to achieve high mass productivity and low costs.

4,

[Brief explanation of drawings]

FIG. 1 is a schematic diagram for explaining the water atomization method. FIG. 2 is a partial vertical sectional view showing the structure of the media stirring mill. F Engineering G. Explanation of symbols 1... Melting furnace 2... Spray tank 3... Spray nozzle 4... Water 5... Drainage tank 11... Medium stirring mill 12... Cylindrical container 13... Rotation Body 14...rod

Claims (1)

[Scope of Claims] (1) A soft magnetic alloy having a microcrystalline phase, characterized in that it has a composition represented by the following formula (I) in terms of atomic ratio. [Formula (I)] (Fe_1_−_aNi_a)_1_0_0_x_y_
z_p_q_rCu_xSi_yB_zCr_pV_q
Mn_r (However, in the above formula (I), 0≦a≦0.5, 0.1≦x≦5, 6≦y≦20, 6≦z≦20, 15≦y+z≦30, 0.5≦p (2) The soft material according to claim 1, wherein the magnetostriction constant λs is within ±5×10^-^6. magnetic alloy. (3) Claim 1, wherein the proportion of the microcrystalline phase is 0.1 to 95%.
Or the soft magnetic alloy described in 2. (4) A method for producing a soft magnetic alloy, which comprises heat-treating an amorphous alloy having a composition represented by the following formula (I) in atomic ratio to obtain a soft magnetic alloy having a microcrystalline phase. [Formula (I)] (Fe_1_−_aNi_a)_1_0_0_x_y_
z_p_q_rCu_xSi_yB_zCr_pV_q
Mn_r (However, in the above formula (I), 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≦2.5 0≦r 3≦p+q+r≦12.5) (5) The amorphous alloy is manufactured by injecting molten alloy from a nozzle and colliding it against a cooling base. The method for producing a soft magnetic alloy according to claim 4.