JPH0412502A - Soft magnetic powder for magnetic shielding, manufacture thereof and magnetic shielding material - Google Patents

Abstract

PURPOSE:To obtain soft magnetic powder for magnetic shielding small in magnetostriction and high in stability against a stress by allowing a peak of a face index (002) to exist in an X-ray diffraction chart of a flat soft magnetic particle. CONSTITUTION:When atomic ratio composition of flat soft magnetic particle for forming magnetic shielding soft magnetic powder in 3-element composition diagram has A:Fe83.8Si9.2Al7, B:Fe84.7Si9.3Al6, C:Fe85.6Si10.4Al4.0, D:Fe84.9Si11.1Al4.0, and E:Fe83.2Si9.8Al7, it is disposed in an area inside a pentagon obtained by sequentially coupling the A, B, C, D, E, and A. Further, in an X-ray diffraction chart of the particle, the peak of a face index (002) exists. Thus, high permeability and low coercive force are obtained, and high magnetic properties are obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a soft magnetic powder suitable for use in magnetic shielding materials, a method for producing the same, and a magnetic shielding material containing this soft magnetic powder.

<Prior Art> Magnetic shielding materials are used to prevent magnetic field generation sources such as magnetized objects from affecting other objects, electric circuits, and the like. As a magnetic shielding material, a metal plate with high magnetic permeability is desirable from the viewpoint of shielding properties, but the uses of metal plates are severely limited in terms of properties, cost, etc.

On the other hand, in the case of a powder material, it can be dispersed in an organic binder and applied in the form of a paint to the areas where shielding is required, or it can be applied to a suitable flexible support to form a shield plate. Various uses are possible.

Regarding magnetic shielding materials using powder with high magnetic permeability,
Various proposals have been made.

For example, JP-A No. 59-201493 discloses a magnetic shielding paint in which flattened powder of a soft magnetic amorphous alloy is mixed into a binder of a polymer compound, and JP-A No. 58-59268 discloses a high-permeability alloy. Japanese Utility Model Publication No. 58-50495 describes the use of a coating film of flaky sendust alloy as a magnetic shielding film. Publication No. 58631 describes Fe-Ni alloys, Fe-Ni-Co alloys, Fe-31-AJ2 alloys, Fe-Ni-Mo alloys, that is, permalloy alloys, molybdenum permalloy alloys, sendust alloys, etc. A magnetic shielding paint made by mixing flat, irregularly shaped particles in a polymer binder is published in Japanese Patent Publication No. 63-39966, and a permalloy magnetic shielding film is published in Japanese Patent Publication No. 1-223627. is Cr=0.5~2
Application of flat magnetic iron powder containing one of the following: 0% by weight, 5i = 0.5 to 9% by weight (1 to 16.5at% in terms of atomic percentage), and Aj2 = 0.5 to 15% by weight. The use of the membrane as a protective membrane for shielding is disclosed.

In these magnetic shielding films and magnetic shielding materials,
The reason for using flat alloy particles is that when a magnetic shielding material in the form of paint is applied, the main surface of the flattened alloy particles is oriented in the in-plane direction of the coating film. This is because the directions match and the high magnetic permeability of the material itself can be utilized due to the small demagnetizing field derived from the flat shape. This is because deterioration of the magnetic properties in the in-plane direction of the coating film due to the demagnetizing field is prevented, and good magnetic shielding properties can be obtained.

<Problems to be Solved by the Invention> The above-described known alloy powder for magnetic shielding has the following problems.

Among Fe-8i-Aβ alloys, an alloy of 9.6 wt % Si, 5.4 wt %, and the balance Fe, in which the maximum magnetic permeability μ layer has a maximum value, is called Sendust alloy.

The saturation magnetostriction constant of Sendust alloy is approximately 0.3 x 10-6 or less, but it is not less than 0, so when applied to magnetic shielding materials, the magnetic properties may deteriorate due to stress during the flattening process or stress applied during use. deteriorates, and the magnetic shielding characteristics as designed cannot be obtained.

Permalloy alloys such as permalloy alloys and molybdenum permalloy alloys are flattened by rolling rather than between folds due to their crystal structure, so the time required for flattening is long and productivity is low. In addition, due to the long flattening process, processing distortion becomes large (which makes it impossible to obtain high magnetic shielding properties. Furthermore, permalloy alloys
The raw material cost is about 5 to 10 times that of Sendust alloy, which is very expensive.

Since Fe-based amorphous alloys are also flattened by rolling, problems similar to those of permalloy alloys arise.

Additionally, permalloy alloys and Fe-based amorphous alloys have large magnetostrictions, so in addition to deterioration of their magnetic properties due to stress applied during flattening, their magnetic properties also deteriorate due to stress applied when they are kneaded with a binder and made into a paint. .

Furthermore, since permalloy alloys are soft, the flat powder is deformed by stress during the coating process, resulting in deterioration of properties.

The present invention was made under these circumstances, and it is an object of the present invention to provide a soft magnetic powder for magnetic shielding that can be quickly and well flattened, has low magnetostriction, and is highly stable against stress, and a method for producing the same. Another object of the present invention is to provide a magnetic shielding material that has a high magnetic shielding effect and is inexpensive by using this soft magnetic powder.

<Means for Solving the Problems> Such objects are achieved by the present invention described in (1) to (11) below.

(1) Fe, Si and A! In the ternary composition diagram (atomic ratio), A: Fe Si Aj2 83.8 9.2 7B: Fe
Si Aj2 84.7 9.3 6C:Fe
Si Aj2 85.6 10.4 4.0D:Fe
Si Al284.9 11
．． 1 4.0E:FeSi
It is composed of flat soft magnetic particles of an alloy having a composition represented by the inner region of a pentagon obtained by connecting A, B, C, D, E, and A in order, when Ag83.2 91 7, In the X-ray diffraction chart of the flat soft magnetic particles, the surface index (002)
A soft magnetic powder for magnetic shielding characterized by the presence of a peak of .

(2) In the Xl51 diffraction chart of the flat soft magnetic particles, the peak height of the surface index (002) is expressed as P(002).
The soft magnetic powder for magnetic shielding according to (1) above, wherein P(002)/P(022) is 20.1%, where P(022) is the peak height of the face index (022).

(3) The soft magnetic powder for magnetic shielding according to (1) or (2) above, wherein the saturation magnetostriction constant λs of the alloy is zero or less.

(4) The soft magnetic powder for magnetic shielding according to any one of (1) to 3) above, wherein the average particle diameter of the flat soft magnetic particles divided by the average thickness thereof is 10 to 3,000.

(5) The weight average particle diameter D6° of the flat soft magnetic particles is 5
~30-, and the average thickness is 1- or less
The soft magnetic powder for magnetic shielding according to any one of ) to 4).

(6) In the ternary composition diagram (atomic ratio) of Fe, Sit; and Aj2, A: Fe Si Aff 83.8 9.2 7B: Fe
Si Al1 84.7 9.3 6C:Fe
Si An 85.6 10.4 4.0D:Fe
Si AJ2 84.9 11.1 4.0E:Fe
Si AA 83.2 9.8 7 When A%B, C, D, E, and A are connected in order, alloy particles having a composition represented by the inner region of a pentagon are flattened to form a flat shape. A method for producing soft magnetic powder for magnetic shielding, comprising the steps of obtaining soft magnetic particles and subjecting the flat soft magnetic particles to heat treatment.

(7) The above (
6) The method for producing a soft magnetic powder for magnetic shielding.

(8) The method for producing a soft magnetic powder for magnetic shielding according to (6) or (7) above, wherein the holding temperature during the heat treatment applied to the flat soft magnetic particles is 100 to 600°C.

(9) The heat treatment causes the alloy particles or the flat soft magnetic particles to have a surface index (0) in the X-ray diffraction chart.
02) The method for producing a soft magnetic powder for magnetic shielding according to any one of (6) to 8) above.

(10) The method for producing a soft magnetic powder for magnetic shielding according to any one of (6) to 9) above, wherein the flattening is performed using a media stirring mill.

(11) A magnetic shielding material comprising the soft magnetic powder for magnetic shielding according to any one of (1) to 5) above and a binder.

For flat soft magnetic particles constituting the soft magnetic powder for magnetic shielding of the present invention, flat soft magnetic particles are obtained by flattening alloy particles having the above composition, and the flat soft magnetic particles are heat-treated. It is manufactured by applying

The present inventors have found that alloy particles having the above composition are easy to form folds, and in particular, when they have a DOz type crystal structure, folds occur very easily, and are suitable for flat soft magnetic particles for magnetic shielding. I found out.

When stress is applied to the alloy particles, pleats are generated and flat soft magnetic particles are obtained. At this time, since the direction of the crystal plane in the interfold plane is regular, deterioration of magnetic properties due to flattening is extremely small.

In addition, flat soft magnetic particles with a high aspect ratio (value obtained by dividing the average particle diameter by the average thickness) can be obtained due to the inter-folds, and
Variations in aspect ratio and particle size are extremely small, making it ideal as a material for magnetic shielding.

Furthermore, compared to permalloy or the like which is flattened by rolling, the time required for flattening is significantly shortened, and productivity is improved.

If the flattening is carried out using a media stirring mill, flattening can be achieved even more quickly, and flattened soft magnetic particles with less variation can be obtained.

In addition, since alloy particles are usually manufactured by rapidly cooling a molten alloy or crushing an ingot, the crystal structure may be disordered, but in this case, heat treatment can improve DO,
The mold crystal structure can be adjusted, and the time required for flattening can be shortened.

The flat soft magnetic particles having the above composition produced in this way have high magnetic permeability and low coercive force, and particularly when they have a DO3 type crystal structure, extremely high magnetic properties can be obtained.
Therefore, it is extremely suitable as a material for magnetic shielding.

Normally, the Do3 type seed crystal structure is lost due to the stress during flattening, but in this case, the DO1 type crystal structure is lost by heat treatment.
An O1 type crystal structure can be formed.

The present inventors have determined that in order to form a DO8 type crystal structure in alloy particles and flattened soft magnetic particles before flattening,
It has been found that low temperature heat treatment at 0°C is sufficient. Therefore, heat treatment can be performed without fear of ignition or sintering.

The presence of the DO8 type crystal structure can be confirmed by the presence of a peak with a plane index (002) unique to the DOa type crystal structure in the X-ray diffraction chart.

In addition, since the saturation magnetostriction constant λs of the alloy with the above composition can be set to zero or less, the magnetic permeability can be reduced by applying stress during flattening or when manufacturing a shield material by kneading with a binder. No deterioration or increase in coercive force occurs, and shielding characteristics do not deteriorate even if stress is applied when used as a magnetic shielding material.

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

The atomic ratio composition of the flat soft magnetic particles constituting the soft magnetic powder for magnetic shielding of the present invention is as follows in the ternary composition diagram shown in FIG. 1: A: Fe Si An 83.8 9.2 7 B: Fe Si Al2 84.7 9.3 6C:Fe
Si Al2 85.6 10.4 4.0D:Fe
Si Al2 84.9 11.1 4.0E:Fe
Si, AJ2 83.2 9.8 7, then A,
This is the inner area of the pentagon obtained by sequentially tying B, C, D%E, and A.

The reasons for limiting the composition will be explained below.

In areas other than the above range, sufficient magnetic shielding characteristics cannot be obtained, and the following problems occur.

Outside the AB line or outside the BC line, the magnetic shielding characteristics deteriorate significantly due to stress application.

Outside the CD line, the time required for flattening becomes longer.

Good magnetic shielding characteristics cannot be obtained outside the DE line.

Outside the EA line, the time required for flattening becomes longer.

A more preferable composition of the flat soft magnetic particles is A%B, where F:Fe Si Al2 85.1 1G, 9 4.0 G:Fe Si Al1 83.5 9.5 7.0 in FIG. This is the inner area of a pentagon obtained by connecting C, F%G%A in order.

Note that the flat soft magnetic particles may contain various additional elements in addition to Fe, Si, and Aρ.

There is no particular restriction on the additive element, and it can be selected from various metal elements such as transition metal elements, metalloid elements, etc. as necessary. The content of such additional elements is Fe%S
When the sum of i and A℃ is 100at%, 10a
It is preferable that it is t% or less.

Note that the flat soft magnetic particles may contain unavoidable impurities such as N, 0, and S, as long as they do not adversely affect the magnetic properties.

In the present invention, a peak of surface index (002) exists in the X-ray diffraction chart of the flat soft magnetic particles. These peaks indicate the existence of a Dos-type crystalline structure.

Also, if the peak height of the surface index (002) is P(002) and the peak height of the surface index (022) is P(022), then P(002)/P(022) is 20.1%. In this case, the effects of the present invention with a Dos-type crystalline structure will be even higher. There is no particular limit to the upper limit of P(002)/P(022), but it is usually 20% or less, especially 0.5
It is about 10%.

In addition, when using a Cu target, the (002) peak is around 2θ=31.2'8°, and the (002) peak is around 2θ=31.2'8°.
22) The peak is 2θ=44. It will appear around 92°.

The soft magnetic powder of the present invention has a maximum magnetic permeability of 20 to 80 μm, particularly 25 to 60 μm, and 1 to 200 e, especially 1 to 14 μm.
A coercive force He of 0e is obtained.

Further, the saturation magnetostriction constant λs of the alloy constituting the flat soft magnetic particles is less than zero, particularly -IOXIO-'~0, and more preferably -3X10-''~-0,0IX10''''.

The dimensions and shape of the flat soft magnetic particles will be explained below.

The average thickness of the flat soft magnetic particles is 1μ or less, especially 0.01μ
It is preferable that it is -1-. Average thickness is 0.01-
If it is less than this, the dispersibility in the binder will decrease when used as a magnetic shielding material. In addition, magnetic properties such as magnetic permeability deteriorate, and shielding properties become insufficient.

On the other hand, if it exceeds 1μ, it will not be possible to form a coating film in which the soft magnetic powder is evenly dispersed when applying a thin layer of magnetic shielding material, and the flat soft magnetic particles in the thickness direction of the coating film will not be formed. As the number of existing particles decreases, the shielding properties become insufficient. In addition, when the average thickness is 0.01 to 0.6-,
Get more favorable results.

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

The average aspect ratio of flat soft magnetic particles is 10 to 3000
In the present invention, the average aspect ratio is a value obtained by dividing the average particle diameter of flat soft magnetic 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, when the average aspect ratio of flat soft magnetic particles having an average thickness within the above range exceeds 3000,
Since the average particle size becomes too large, breakage tends to occur when kneading with a binder, resulting in deterioration of magnetic properties.

In addition, the average particle size in this case means the weight average particle size D50, and the weight of the flat soft magnetic particles constituting the soft magnetic powder is integrated from the smallest particle size, and this value is the weight average particle size D50 of the entire soft magnetic powder. This is the particle size of the flat soft magnetic particles when they reach 50% of the weight. 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 are described in, for example, "Powder to Industry J VOL, 19 No. 7 (1987).

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

The soft magnetic powder of the present invention has a D5 determined in this way.
It is preferable that 0 is 5 to 30-.

In the main surface shape of such flat soft magnetic particles, the length of the major axis (maximum diameter) is a, and the length of the minor axis (minimum diameter) is b.
When the average axial ratio a/b is required to have directionality in the magnetic shield, it is desirable that the value is as large as possible, such as 1.2 or more. 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 method for producing the soft magnetic powder of the present invention will be explained below.

In the present invention, alloy particles having the composition shown in FIG. 1 are flattened to obtain flat soft magnetic particles.

The alloy particles may be produced by rapidly cooling a molten alloy or crushing an alloy ingot, and the method is not particularly limited.

Although there are no particular limitations on the method for rapidly cooling the molten alloy, it is preferable to use a water atomization method because alloy particles of a desired particle size can be obtained without a pulverization step and productivity is high.

The water atomization method involves injecting high-pressure water into molten alloy to solidify and
After pulverizing, the powder is cooled in water, and the details thereof are described in, for example, Japanese Patent Application No. 1-12267 by the present inventors.

In addition to the water atomization method, a method may be used in which the molten metal collides with a cooling substrate to obtain a thin strip, flake, or granular alloy. Such methods include the single roll method, twin roll method, or An example is the atomization method. In these methods, the resulting rapidly solidified alloy is crushed if necessary,
Alloy particles may have a desired particle size.

When producing alloy particles by grinding an alloy ingot,
It is preferable that the ingot is subjected to a compaction treatment and then pulverized.

The average particle size of the alloy particles may be appropriately determined depending on the particle size and aspect ratio of the target flat soft magnetic particles, but is usually 5 to 30-1, preferably 7 to 30-1 in weight average particle size D50.
It may be set to 20-.

Note that the alloy particles are preferably subjected to heat treatment to adjust the crystal structure.

There is no particular restriction on the means for flattening the alloy particles, and any means may be used as long as the desired flattening is possible.

However, in the present invention, flattening of the alloy particles mainly progresses between the pleats, so it is preferable to use a means that can efficiently perform the inter-fold spacing.

Examples of such means include a medium stirring mill, a transfer ball mill, and the like, and among these, it is particularly preferable to use a medium stirring mill.

A media 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 Application Laid-Open No. 61-259739 and Japanese Patent Application No. 1-12267 filed by the present inventors. There is.

The flat soft magnetic particles obtained in this way are preferably subjected to heat treatment. This heat treatment is for forming a Dos type crystal structure as described above.

The holding temperature and temperature holding time during this heat treatment and the heat treatment applied to the alloy particles before flattening are 100
It is preferable to set it as 10 minutes - 10 hours at -600 degreeC. If the holding temperature or temperature holding time is less than the above range, the effect of heat treatment will be insufficient, and if it exceeds the above range, ignition or sintering will easily occur.More preferable heat treatment conditions are 300 to 500°C for 30 minutes to It is 2 hours.

Note that the heat treatment is preferably performed in vacuum or in an atmosphere of an inert gas such as nitrogen, hydrogen, or Ar.

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

The magnetic shielding material of the present invention contains the soft magnetic powder thus obtained and a binder, and the soft magnetic powder is dispersed in the binder.

The magnetic properties of the magnetic shielding material of the present invention are expressed as the maximum magnetic permeability μ in a DC magnetic field when converted to 100% material, which is 5.
0 or more, preferably 100 or more, especially 150 to 400,
Further, a value of 180 to 350 is obtained, and a value of 2 to 200e, particularly 2 to 150e, is obtained as the coercive force Hc.

Such magnetic properties provide a sufficient magnetic shielding effect.

The filling rate of soft magnetic powder in the magnetic shielding material 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.

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.

The binder used in the present invention is not particularly limited and can be appropriately selected from known thermoplastic resins, 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 of the present invention is formed into a film or a thin plate and used for magnetic shielding, the thickness of the magnetic shielding material is preferably 5 to 200 #Im.

This thickness range is selected because the magnetic shielding material of the present invention has the above-mentioned magnetic properties, so it exhibits a high magnetic shielding effect even at a thickness of 5 -, and the shielding material does not become magnetically saturated. This is because when shielding a magnetic field having an intensity of 200 μm, the magnetic shielding effect is not significantly improved even if the thickness exceeds 200 μm, and a thickness of 200 μm or less is advantageous in terms of cost.

In addition, when the magnetic shielding material of the present invention is molded or coated into a desired shape, it can be made into a highly directional magnetic shielding material by applying an orienting magnetic field or mechanically orienting it. When the shielding material is 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-mentioned 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.

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

[Example 1] In this example, flat soft magnetic particles having various compositions were produced to confirm the effects of the present invention.

Alloy particles were produced by a water atomization method, then flattened by a media stirring mill, and further heat treated to obtain soft magnetic powder consisting of flat soft magnetic particles.

The composition of the flat soft magnetic particles, the holding temperature and temperature holding time during heat treatment are shown in Table 1 below.

Flattening using a media stirring mill was carried out until the weight average particle diameter D6 of the flat soft magnetic particles reached 15°, and the time required for this flattening was measured.

The results are shown in Table 1.

The average thickness was measured using an analytical scanning electron microscope. was measured using a particle size analyzer using light scattering.

After the heat treatment, the flat soft magnetic particles were subjected to X-ray diffraction analysis using a Cu target, and from the obtained X-ray diffraction chart, the peak height of the surface index (002) Pfo02) and the peak height of the surface index (022) were determined. Find P ((122) and P
(002)/P (022) was calculated.

Table 1 shows the results of X-ray diffraction chart analysis.

The saturation magnetostriction constant S for each composition shown in Table 1 was measured. For the measurements, 5×5×20 m+++ samples of each composition were used, and after being subjected to the heat treatments shown in Table 1, measurements were made using the three-terminal capacitance method. The results are shown in Table 1.

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 r S-LEC A (manufactured by Tanezu Kagaku Co., Ltd.)] 100 parts by weight polyurethane [Niraporan 2304 (manufactured by Nippon Polyurethane Co., Ltd.)] 1100 parts by weight in terms of solid content) (Curing agent) Polyisocyanate [Coronate HL (manufactured by Nippon Polyurethane Co., Ltd.)] 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 shielding material was coated to a thickness of 25 μm on a long PET substrate with a thickness of 75 μm, and after being wound into a roll,
It was cured by heating at ℃ for 60 minutes. This was cut into a sheet shape to obtain a shield plate sample. As the magnetic properties of the shield plate sample, Table 1 shows the coercive force (Hc) when converted to 100% of the material.

The produced shield plate sample was placed on a magnet, and the leakage magnetic flux φ at a position 0.5 cm from the shield plate sample was measured, and this and the magnetic flux φ when there was no shield plate were measured. The ratio φ/φ0 was calculated and expressed as a relative value with sample N011 as 100, which was taken as the shield ratio. Table 1 shows the results.
Shown below.

In addition, in order to examine the deterioration of magnetic shielding characteristics due to stress application, a constant load was applied to each magnetic shielding material sample, and the rate of change in magnetic shielding characteristics was examined. The results are shown in Table 1.

Note that under these measurement conditions, if the shield ratio is a value of 150 or less, a sufficient shielding effect is obtained; however, in reality, the smaller the shield ratio is, the more preferable it is.

For comparison, particles of sendust alloy, various permalloy alloys, and Fe-based amorphous alloys were used and flattened in the same manner as above to produce soft magnetic powders.

Regarding these, measurements and evaluations similar to those described above were performed.

The results are shown in Table 1.

From the results shown in Table 1, the effects of the present invention are clear.

That is, in samples N011 to 3, which are examples of the present invention,
The flattening time is short, and the saturation magnetostriction constant λs is a negative value. In addition, it has a low coercive force required for a magnetic shielding material, has a high shielding ratio when used as a magnetic shielding material, and hardly deteriorates even when stress is applied.

On the other hand, samples Nos. 4 to 7 having compositions outside the AE line or outside the CD line in FIG. 1 take a long time to flatten and are inferior in productivity, and have poor magnetic shielding properties.

In sample No. 5.7.9 (Se'/tas alloy) having a composition outside the AB line or outside BC4i, the magnetic shielding characteristics deteriorated significantly due to stress application.

In samples No. 4 and 6 having compositions outside the ED line, the magnetic shielding characteristics are improved by stress application, but the characteristics are basically low.

The permalloy alloys and amorphous alloys of samples No. 10 to 12 had a flattening time of 2 times longer than the samples of the present invention.
It is twice to three times longer and has poor productivity. In addition, the shielding properties are low, and the rate of deterioration due to stress is also low.

[Example 2] In this example, 85,1wt, which has a composition within the range of the present invention,
Using a %Fe-10,1wt%5i-4,8wt%Aj alloy, the heat treatment conditions were varied and the properties were investigated. The conditions for each measurement were the same as in Example 1.

The results are shown in Table 2 below.

Further, the X-ray diffraction charts of samples Nos. 2513 and 21 using Cu targets are shown in FIG. 2 and FIG. 3, respectively.

Table (%) (Relative value) 21 None None 17.0
20022 200x60 1.0
4.0 10523 300X60
1.7 5.0 10124
400x60 3.6 8.0 9
525 500X60 4.6
9.0 10026 700x60 Unmeasurable -- Ignition [Example 3] Alloy particles having the composition shown in Table 1 above were heat treated at 450°C for 1 hour, and then flattened under the same conditions as Example 1. As a result, the flattening time was reduced by more than 10%.

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

<Effects of the Invention> The flat soft magnetic particles constituting the soft magnetic powder of the present invention have high magnetic permeability and low coercive force, and also have a saturation magnetostriction constant λs
can be kept below zero, and has good corrosion resistance, so it is extremely suitable as a material for magnetic shielding.

In addition, since alloy particles that easily form folds are used as raw materials, flat soft magnetic particles with a high aspect ratio can be produced in a short time, and after flattening, heat treatment is performed to form a predetermined crystal structure. Extremely high magnetic properties can be obtained.

The magnetic shielding material of the present invention using such soft magnetic powder is inexpensive and has high performance, and can be applied to an extremely wide range of applications in addition to magnetic shielding for speakers, CRTs, etc.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a ternary composition diagram showing the composition of flat soft magnetic particles constituting the soft magnetic powder of the present invention. Figures 2 and 3 show the X of flat soft magnetic particles, respectively.
This is a line diffraction chart. Patent Press Osamu Oshiro Jindo TDC Co., Ltd.

Claims (11)

[Claims] (1) In the ternary composition diagram (atomic ratio) of Fe, Si and Al, A: Fe_8_3_. _8Si_9_. _2Al_7B
:Fe_8_4_. _7Si_9_. _3Al_6C:
Fe_8_5_. _6Si_1_0_. _4Al_4_
．． _0D:Fe_8_4_. _9Si_1_1_. ＿１
Al_4_. _0E:Fe_8_3_. _2Si_9_
．． _8Al_7 is composed of flat soft magnetic particles of an alloy having a composition represented by the inner region of a pentagon obtained by connecting A, B, C, D, E, and A in order, and In the X-ray diffraction chart of soft magnetic particles,
A soft magnetic powder for magnetic shielding characterized by the presence of a peak of plane index (002). (2) In the X-ray diffraction chart of the flat soft magnetic particles, when the peak height of the plane index (002) is P(002) and the peak height of the plane index (022) is P(022), P The soft magnetic powder for magnetic shielding according to claim 1, wherein (002)/P(022)≧0.1%. (3) The soft magnetic powder for magnetic shielding according to claim 1 or 2, wherein the saturation magnetostriction constant λs of the alloy is less than or equal to zero. (4) The soft magnetic powder for magnetic shielding according to any one of claims 1 to 3, wherein the average particle diameter of the flat soft magnetic particles divided by their average thickness is 10 to 3,000. (5) Weight average particle diameter of the flat soft magnetic particles D_5_0
The soft magnetic powder for magnetic shielding according to any one of claims 1 to 4, wherein the powder has an average thickness of 5 to 30 μm and an average thickness of 1 μm or less. (6) In the ternary composition diagram (atomic ratio) of Fe, Si and Al, A: Fe_8_3_. _8Si_9_. _2Al_7B
:Fe_8_4_. _7Si_9_. _3Al_6C:
Fe_8_5_. _6Si_1_0_. _4Al_4_
．． _0D:Fe_8_4_. _9Si_1_1_. ＿１
Al_4_. _0E:Fe_8_3_. _2Si_9_
．． _8Al_7, flatten the alloy particles having the composition represented by the inner region of a pentagon obtained by connecting A, B, C, D, E, and A in order to obtain flattened soft magnetic particles. 1. A method for producing soft magnetic powder for magnetic shielding, comprising the step of heat-treating soft magnetic particles. (7) The method for producing a soft magnetic powder for magnetic shielding according to claim 6, further comprising the step of subjecting the alloy particles to heat treatment. (8) The method for producing soft magnetic powder for magnetic shielding according to claim 6 or 7, wherein the holding temperature during the heat treatment applied to the flat soft magnetic particles is 100 to 600°C. (9) The heat treatment causes the alloy particles or the flat soft magnetic particles to have a surface index (0) in the X-ray diffraction chart.
9. The method for producing a soft magnetic powder for magnetic shielding according to claim 6, wherein a peak of 02) appears. (10) The method for producing soft magnetic powder for magnetic shielding according to any one of claims 6 to 9, wherein the flattening is performed by a media stirring mill. (11) A magnetic shielding material comprising the soft magnetic powder for magnetic shielding according to any one of claims 1 to 5 and a binder.