JPH05295402A - Flat fe base soft magnetic alloy powder and its production and coating liquid for magnetic shielding containing the powder - Google Patents

Abstract

PURPOSE:To develop the soft magnetic Fe base alloy powder having excellent magnetic shielding characteristics by forming an Fe alloy melt having a specific compsn. as droplets by a gas spraying, then quenching and solidifying the droplets. CONSTITUTION:The melt 1 of the Fe base alloy of the compsn. expressed by general formula Fe100-a-bMaBb or F100-c-d-eMcBdMe' (where M is one or two kinds among Ti, Zr, Hf, Nb and Ta; M is one or two kinds of Cu and Au; 5<=a<=1, 1<=b<=8, 5<=c<=10, 1<=d<=8, 1<=e<=3 by atomic %) is discharged from a nozzle 2 in the bottom of a container and an inert gas, such as Ar, is injected from a nozzle 3 to the molten flow of the alloy to form fine liquid drops shape 5 which are then brought into collision against a rotationally quenching body 4 having a circular conical shape. At least >=90% covolumetric rate of the alloy liquid drops 5 is the solid soln. of Fe having a bcc structure of <50nm average crystal grain size and the balance is the flat Fe base fine powder of an amorphous phase having >5 aspect ratio, >5mum minor diameter and <500mum major diameter. The powder is heat treated at 450 to 700 deg.C and the Fe base alloy powder having the excellent magnetic shielding characteristic is produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat Fe-based alloy powder having excellent soft magnetism, a method for producing the same, and a magnetic shield coating containing the same.

[0002]

2. Description of the Related Art A magnetic shield paint can obtain a magnetic shield effect by simply applying it, and is therefore suitable for shielding an arbitrary shape. The magnetic shield paint is generally composed of a paint resin component to which a filler made of soft magnetic powder is added.

As the filler, a soft magnetic powder having a high magnetic permeability is useful. As such a high magnetic permeability material,
Co-based amorphous alloys are known. When a flat powder having a large aspect ratio (ratio of major axis to thickness) is used as the filler, the filler is arranged in the paint resin with orientation due to its shape, that is, the filler is arranged in the direction having the lowest demagnetizing field coefficient. Therefore, the magnetic permeability in the surface direction of the coating film is increased.

As a method for producing such a filler,
There is known a method in which a ribbon, spherical or lumpy powder obtained by quenching a molten alloy is mechanically crushed into flakes.

Further, in recent years, a method of solidifying a soft magnetic powder has been widely adopted as a method of manufacturing a core or the like in order to complicate the shape of a magnetic material part and to use it in a higher frequency region.

Further, the Fe-Zr-B type amorphous alloy ribbon is heat-treated to form a uniform fine crystalline structure of 15-20 nm, whereby F having both high magnetic permeability and high magnetic flux density is obtained.
It has been reported that an e-based soft magnetic material can be obtained (Mate
rials Transactions, JIM, Vol.31, No.8 (1990), pp74
3).

[0007]

The Co-based amorphous alloy is
It has a high magnetic permeability, but its saturation magnetic flux density is 10,000 G (Gauss) or less, and since the Co price has surged in recent years, it has a large saturation magnetic flux density as an alternative material.
Moreover, there is a demand for Fe-based soft magnetic materials having high magnetic permeability.

However, since the Fe-based soft magnetic amorphous alloy has a large magnetostriction, it has a drawback that the magnetic permeability is deteriorated due to strain due to mechanical crushing. Further, in the case of mechanical crushing, oleic acid, stearic acid or the like is added as an auxiliary agent in addition to the soft magnetic material, or the method is carried out by a wet method. Therefore, a method for directly producing a flat powder from a molten metal has been desired.

On the other hand, when the magnetic material parts are manufactured by solidifying the powder, since the powder used is almost spherical or lumpy, it is impossible to impart magnetic anisotropy, and the particles are arranged in the direction of low demagnetizing field. It has been desired to increase the magnetic permeability by using a flat powder that is easy to do.

As a method for obtaining a large amount of powder, an atomizing method using an inert gas is effective, but the cooling rate is 10
^{Since it was} about ³ ° C./sec, an amorphous single-phase powder could not be obtained with the Fe—Zr—B system.

Accordingly, an object of the present invention is to provide a high magnetic permeability flat soft magnetic powder having a high magnetic permeability and a high saturation magnetic flux density and a good orientation when applied as a paint, and an industrial production of this powder. Method and a magnetic shield coating containing this powder.

[0012]

In order to obtain a more excellent flat soft magnetic alloy powder, the present inventors have investigated the texture of powders having various compositions and various heat treatments. And the magnetic characteristics were investigated. As a result, the amorphous powder produced by rapidly solidifying the melt of the alloy having the specific composition, by heat treatment in a specific temperature range,
An Fe solid solution having an average particle size of 50 nm or less and a bcc structure is
A powder having a structure of at least 90% in volume ratio was obtained, and as a result of measuring the magnetic characteristics of this powder, it was found that the saturation magnetic flux density was 10,000 G or more, and the present invention was completed.

[0013] That is, high permeability flat soft magnetic powder of the present invention, (1) the general formula _{Fe 100-ab M a B b} ( where one M is selected Ti, Zr, Hf, Nb, Ta, Or 2
Is an element of at least one kind, and a and b are 5% a ≦ 10 in atomic%,
1 ≦ b ≦ 8. ), Or (2) the general formula Fe
_100-cde M _c B _d M ' _e (However, M is Ti, Zr, H
one or more elements selected from f, Nb, and Ta,
M ′ is one or two elements selected from Cu and Au, and c, d, and e are 5% or less in atomic% and 5 ≦ c ≦ 10 or 1 ≦ b ≦ 8.
1 ≦ e ≦ 3. ), Having a composition of fine crystals having an average crystal grain size of 50 nm or less, at least 90% or more in volume ratio, and having a thickness of 5 μm or less and an aspect ratio (ratio of major axis to thickness) of 5 or more. It has a shape with a minor axis of 5 μm or more and a major axis of 500 μm or less.

Further, in the method for producing the flattened soft magnetic powder having high magnetic permeability of the present invention, the molten alloy having the composition represented by the general formula (1) or (2) is caused to flow out from the nozzle, and the molten metal is gasified. By generating droplets of the molten metal by spraying, the droplets collide with the surface of the conical or horn type rotary cooling body arranged in the droplet flow direction before solidifying and rapidly cooling and solidifying the droplets. A powder having an amorphous phase is obtained, and the powder is heat-treated in the temperature range of 450 to 700 ° C.

Furthermore, the magnetic shield paint of the present invention is characterized by containing a paint resin component and the flat Fe-based soft magnetic alloy powder.

The present invention will be described in more detail below.

The reason why the alloy composition is limited in the present invention will be described. If the M content is less than 5 atom% or more than 10 atom% and the B content is less than 1 atom%, an amorphous single phase is obtained. If the amount of B is more than 8 atomic%, boride will be precipitated and the crystal grain size will be 50 nm or more in the structure after heat treatment, which is not preferable. Further, addition of M ′ is preferable because it has the effect of forming nuclei during crystallization and suppressing the growth of crystal grains.
If the amount exceeds 3 atomic%, an amorphous single phase cannot be obtained, and the crystal grain size becomes 50 nm or more as in the above case, which is not preferable.

The reason why the shape of the powder is limited is as follows. When the thickness exceeds 5 μm, when used as a filler for paint, the smoothness of the coating film deteriorates and the actual aspect ratio becomes small, which is not preferable. Also, the minor axis is 5 μm
Below, the aspect ratio becomes smaller and the major axis becomes 500μ.
If it exceeds m, the strength of the coating film deteriorates, which is not preferable. Further, if the aspect ratio is less than 5, the demagnetizing field coefficient of the powder itself becomes large, and it becomes difficult to arrange the powder with orientation when used as a paint or when solidified.

Further, the reason for limiting the amount of fine crystals in the structure will be described. The fine crystals have a volume ratio of 90%.
In the following cases, the part other than the fine crystal grains is an amorphous phase,
Amorphous metals do not exhibit excellent soft magnetic characteristics due to the Invar effect, so that the soft magnetic characteristics are deteriorated as a whole, which is not preferable.

In a preferred aspect of the present invention, the fine crystals are made of an Fe solid solution having a bcc structure.

In the production method of the present invention, the reason why the heat treatment temperature of the obtained amorphous powder is limited will be described. When the heat treatment temperature is lower than 450 ° C., the amount of the crystalline phase becomes 90% or less by volume. In addition, when the temperature exceeds 700 ° C, bcc
The Fe solid solution having a structure is decomposed, coarse intermetallic compounds are deposited, and soft magnetic properties are deteriorated, which is not preferable.

The magnetic shield paint of the present invention may be any one as long as it contains the resin component for paint and the flattened Fe-based soft magnetic alloy powder, but it imparts good magnetic shield properties and at the same time as a paint. In order not to impair the characteristics, the compounding amount of the flat Fe-based soft magnetic alloy powder is 15 to 15.
It is preferably 35% by volume.

The resin component for paint may be any resin generally used in paints, and various resins such as vinyl chloride, vinyl acetate, acrylic, polyurethane, epoxy and polyester can be used. Further, in addition to the resin component for paint and the alloy powder, if necessary, a solvent,
You may add various additives normally used for coating materials, such as a hardening agent, a pigment, a thickener, a dispersant, and a stabilizer.

The flat Fe-based soft magnetic alloy powder of the present invention is
In addition to the magnetic shield paint, it can be added to, for example, plastics and the like to be used for producing a sheet, a cover, a housing and the like having magnetic shield characteristics.
Further, by solidifying this powder with an appropriate resin binder, a core material or the like can be prepared.

[0025]

The flattened Fe-based soft magnetic alloy powder of the present invention is
The composition is represented by the general formula (1) or (2), and at least 90% or more by volume has a structure composed of fine crystals having an average crystal grain size of 50 nm or less. It has magnetic permeability and high saturation magnetic flux density. Therefore, it has excellent magnetic shield characteristics,
It can be used for various purposes as a magnetic shield material.

Further, since it has a thickness of 5 μm or less, an aspect ratio of 5 or more, a short diameter of 5 μm or more, and a long diameter of 500 μm or less, when it is used as a filler for a magnetic shield paint, the smoothness and strength of the paint may be impaired. However, the powder can be favorably oriented and the magnetic shield characteristics can be improved.

On the other hand, according to the production method of the present invention, the powder having the above-mentioned shape can be industrially produced efficiently. Further, by heat-treating the amorphous powder produced by rapid solidification in the temperature range of 450 to 700 ° C., the powder having the above-described fine crystalline structure can be efficiently produced.

According to the magnetic shield coating composition of the present invention, by containing the flat Fe-based soft magnetic alloy powder, a coating film having excellent magnetic shield properties can be obtained without impairing smoothness and strength. Moreover, the magnetic shield can be provided only by applying the magnetic shield to a required portion.

[0029]

FIG. 1 shows an example of an apparatus for producing the alloy powder of the present invention. That is, a nozzle 2 for flowing out a molten alloy 1 melted in a crucible is installed, and an atomizing nozzle 3 for blowing a high-pressure injection gas to the falling molten metal 1 is installed. Atomizing nozzle 3
Are arranged, for example, in a circular shape so as to surround the nozzle 2, and have a structure in which a high-speed gas is ejected from a large number of ejection ports toward the flow of the molten metal 1. A cone-shaped rotary cooling body 4 is arranged below the nozzle 2 with its rotation axis slightly laterally displaced from directly below the nozzle 2.

Therefore, a high-pressure jet gas is blown from the atomizing nozzle 3 to the flow of the molten metal 1 flowing out of the nozzle 2 and falling, whereby droplets 5 of the molten metal 1 are formed. The droplets 5 spread and spread downward, collide with the conical surface of the rotary cooling body 4 and rapidly solidify to form a flattened alloy powder 6.

In this case, the injection gas pressure from the atomizing nozzle 3 is preferably 30 kg / cm ² or more. In addition, various kinds of gas such as argon, helium, nitrogen, or a mixed gas thereof can be used as the injection gas. Further, the rotary cooling body 4 is preferably cooled to 50 ° C. or lower by means such as water cooling,
The rotation speed is preferably 2000 to 10000 rpm.

A more specific description will be given below with reference to experimental examples. (1) Preparation of alloy powder Sample No. 1 shown in Table 1 (described later) using the apparatus shown in FIG. Alloys having compositions of 1 to 10 were placed in crucibles and melted at 1300 ° C. to obtain molten metal. This molten metal 1 is made to flow out from the nozzle 2 and dropped, and an argon gas is sprayed onto this molten metal 1 from the atomizing nozzle 3 at a pressure of 100 kg / cm ² to form droplets 5.
It collided with the rotary cooling body 4 having 0 mm, a cone angle of 90 degrees, and a rotation speed of 7,200 rpm, to obtain an oval flat powder 6.

The alloy powders of the respective compositions obtained by the above method were classified, and those having shape characteristics shown in Table 2 (described later) were separated. The thickness of the present invention is 5
The yields of powders each having a diameter of less than μm, a minor axis of 5 μm or more, a major axis of 500 μm or less, and an aspect ratio of 5 or more were all over 95%.

(2) Heat treatment of powder Sample No. For powders obtained with the alloy of 3,
As shown in Table 3 (described later), heat treatment was performed in vacuum at various temperatures and various times, and the structure, the crystal grain size, and the magnetic characteristics of the core produced by solidification of this powder were examined.

(3) Coating test A coating material was prepared by mixing 85% by volume of an acrylic resin as a resin component for coating material and 15% by volume of each powder obtained above. And thickness 2mm, width 50mm, length 150
A copper plate of mm was prepared, ultrasonically washed in trichlene, and each of the paints prepared above was brush-coated so that the coating film thickness was about 100 μm. After drying, the state of the coating film was observed. The results are shown in Table 2.

From the results shown in Table 2, the thickness is 5 μm or less and the minor axis is 5
It can be seen that a coating material containing a powder having a particle diameter of μm or more, a major axis of 500 μm or less, and an aspect ratio of 5 or more is preferable.

(4) Solidification of powder 30% by volume of a phenol resin as a resin binder and 70% by volume of each powder obtained above are mixed to obtain 15
By hot pressing at 0 ° C. and a pressure of 100 kg / cm ² for 10 minutes, a core having an outer diameter of 30 mm, an inner diameter of 18 mm and a thickness of 5 mm was produced, and the magnetic characteristics were measured. The results are shown in Table 3.

From the results shown in Table 3, the sample No. having a crystal grain size of 25 μm or less and a bcc structure was used. 1, 2, 3-, 3
-, 3, 4, and 5 (Example products) are sample Nos. Compared to 3- and 16 (comparative example products),
It can be seen that the saturation magnetic flux density is large and the magnetic permeability is high. In addition, the sample No. 1 having an intermetallic compound formed by heat treatment at a high temperature. It can be seen that the 3- (comparative example product) has reduced magnetic permeability.

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

[Table 3]

[0042]

As described above, according to the present invention,
The molten alloy of a specific composition is gas atomized into droplets, and the droplets are collided with a conical or horn type rotary cooling body to be powdered into a specific shape and amorphized by a quenching effect. By heat-treating the powder at a specific temperature, a flat F having a fine crystal structure of a specific composition
An e-based soft magnetic alloy powder can be obtained. This powder is
Since it has excellent soft magnetic properties, high magnetic permeability, and high saturation magnetic flux density, it has excellent magnetic shielding properties and can be used as a magnetic shielding material in various applications. Further, since it has a specific shape characteristic, when it is used as a paint filler, it can be aligned with the orientation due to the leafing phenomenon while maintaining a good state of the coating film, and the magnetic permeability can be increased. Also,
Also when a core is produced using this powder, the powder is similarly arranged with orientation, so that the magnetic permeability can be increased compared to the case where a conventional spherical powder is used.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an example of an apparatus for producing an alloy powder of the present invention.

[Explanation of symbols]

 1 Molten Metal 2 Nozzle 3 Atomizing Nozzle 4 Rotating Coolant 5 Droplet 6 Flat Alloy Powder

 ─────────────────────────────────────────────────── ─── Continuation of front page (71) Applicant 000010098 Alps Electric Co., Ltd. 1-7 Yukiya Otsuka-cho, Ota-ku, Tokyo (72) Inventor Ken Masumoto 3-8-22 Uesugi, Aoba-ku, Sendai-shi, Miyagi (72) ) Inventor Akihisa Inoue Kawauchi Muzen, Aoba-ku, Sendai-shi, Miyagi 11-806 (72) Inventor Masahiro Oguchi 1-9-9 Yaesu, Chuo-ku, Tokyo Imperial Piston Ring Co., Ltd. (72) Inventor Katsuyuki Yoshizawa 1-9-9 Yaesu, Chuo-ku, Tokyo Within Teikoku Piston Ring Co., Ltd. (72) Inventor Kiyosaku Suzuki 1-7 Yukiya Otsukacho, Ota-ku, Tokyo Alps Electric Co., Ltd. (72) Inventor Akihiro Makino Tokyo Alps Electric Co., Ltd. 1-7 Otsuka-cho, Yukiya, Ota-ku, Tokyo

Claims (5)

[Claims] 1. The general formula Fe _100-ab M _a B _b (where M is
Is one or more elements selected from Ti, Zr, Hf, Nb, and Ta, and a and b are 5% or less in atomic%.
0 and 1 ≦ b ≦ 8. ), Having a composition of fine crystals having an average crystal grain size of 50 nm or less, at least 90% by volume of which has a thickness of 5 μm or less and an aspect ratio (ratio of major axis to thickness) of 5 or more. , Short diameter 5μ
A flat Fe-based soft magnetic alloy powder having a shape of m or more and a major axis of 500 μm or less. 2. The general formula Fe _100-cde M _c B _d M ' _e
(However, M is one or more elements selected from Ti, Zr, Hf, Nb and Ta, M ′ is one or two elements selected from Cu and Au, and c, d and e Has a composition represented by 5% to 10% in atomic%, 1% to 8%, and 1% to 3%, and at least 90% by volume is
It is characterized by having a structure composed of fine crystals having an average crystal grain size of 50 nm or less and having a thickness of 5 μm or less, an aspect ratio (ratio of major axis to thickness) of 5 or more, minor axis of 5 μm or more, and major axis of 500 μm or less. Flat Fe-based soft magnetic alloy powder. 3. The flat Fe-based soft magnetic alloy powder according to claim 1, wherein the fine crystals of the structure are made of an Fe solid solution having a bcc structure, and the rest of the structure is made of an amorphous phase. 4. The general formula Fe _100-ab M _a B _b (provided that M
Is one or more elements selected from Ti, Zr, Hf, Nb, and Ta, and a and b are 5% or less in atomic%.
0 and 1 ≦ b ≦ 8. ), Or the general formula Fe
_100-cde M _c B _d M ' _e (However, M is Ti, Zr, H
one or more elements selected from f, Nb, and Ta,
M ′ is one or two elements selected from Cu and Au, and c, d, and e are 5% or less in atomic% and 5 ≦ c ≦ 10 or 1 ≦ b ≦ 8.
1 ≦ e ≦ 3. ), The molten alloy having the composition shown by (1) is flown out from the nozzle, and the molten metal is sprayed with a gas to generate droplets of the molten metal. A powder consisting of an amorphous phase is obtained by impinging the liquid droplets on the surface before solidifying to rapidly solidify the liquid.
A method for producing a flat Fe-based soft magnetic alloy powder, characterized by performing heat treatment in a temperature range of 00 ° C. 5. A resin component for coating material, and claim 1, 2 or 3.
A magnetic shield coating material containing the above described flat Fe-based soft magnetic alloy powder.