JP2001300697A - Method for producing amorphous ribon for nano- crystallized material and method for manufacturing nano-crystallized soft magnetic material using this ribon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of an Fe base amorphous ribon with which a nano-crystallized material excellent in magnetic characteristic can be obtained, and a manufacturing method of a nano-crystallized soft magnetic material using this amorphous ribon. SOLUTION: This amorphous ribon for nano-crystallized material is produced by pouring molten metal composed of <=10 mol% B and <=15 mol% one or more elements in 4A, 5A and 6A groups in the periodic table of elements and the balance substantially Fe into a moving cooling body while introducing gas having >=32 J/mol.K specific heat at constant pressure at 30 deg.C toward this molten metal. The nano-crystallized soft magnetic material having <=100 nm average crystallized grain diameter can be obtained by applying the heat treatment to this ribon at not lower than the crystallized temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing an Fe-based amorphous ribbon for use as a nanocrystalline material and a method for producing a nanocrystalline soft magnetic material using the same.

[0002]

2. Description of the Related Art As a production method for producing an amorphous ribbon, a liquid quenching method is widely known. As the liquid quenching method, there are a single roll method, a twin roll method, a centrifugal method, and the like, but from the viewpoint of productivity and ease of maintenance,
The single roll method in which a molten metal is supplied onto one cooling roll rotating at high speed and rapidly solidified to obtain a ribbon is excellent. It is known that an amorphous ribbon adjusted to a specific component is manufactured by the above-described method, and a nanocrystalline material having an average crystal grain size of 100 nm or less can be obtained by heat-treating and crystallizing the amorphous ribbon as a precursor. Have been.

As a composition from which such a nanocrystalline material can be obtained, typical compositions are Fe-Si-B described in Japanese Patent Publication No. 4-4393, Japanese Patent Publication No. 7-74419, and Japanese Patent No. 2812574. -(Nb, Ti, Hf, Mo,
W, Ta) -Cu alloy, Fe- (Co, Ni) -Cu-
Si-B- (Nb, W, Ta, Zr, Hf, Ti, M
o) alloy, Fe- (Hf, Nb, Zr) -B alloy, Fe
-Cu- (Hf, Nb, Zr) -B alloy and the like are known. In addition, the nanocrystalline material has almost no thermal instability seen in the amorphous alloy, has little change with time,
Because of its low magnetostriction and high magnetic permeability, it is used for common mode choke coils, pulse transformers, earth leakage breakers and the like.

[0004]

According to the study of the present inventors, it has been confirmed that in a nanocrystalline material, it is important that the amorphous ribbon as a precursor before the crystallization by heat treatment has no crystalline phase. did. Even if the crystal phase in the amorphous phase before the heat treatment is very slightly generated on the surface layer, the magnetic properties after the heat treatment at a crystallization temperature or higher are deteriorated. This is because the crystal phase precipitated during casting has a particle size of 0.2 to
It is a dendrite-like crystal that is not a nanocrystal of 1 μm and is abnormally larger than a crystal phase crystallized from an amorphous phase by heat treatment. Therefore, the structure after heat treatment becomes non-uniform, and the crystal magnetic anisotropy increases. This causes deterioration of magnetic characteristics.

[0005] Therefore, it is important that the amorphous ribbon as a precursor of the nanocrystalline material is not crystallized. For this reason, it was cooled as quickly as possible during ribbon production. However, if the temperature is too low, the ribbon breaks during production, and a problem arises in that the ribbon cannot be continuously collected. In addition, since the nanocrystalline material is brittle, the amorphous ribbon before heat treatment is wound into a toroidal shape or punched to obtain a desired shape, and then used after heat treatment at a crystallization temperature or higher. There is also a problem in that it becomes difficult to continuously produce a wound magnetic core or the like if there is a broken portion.
Therefore, an object of the present invention is to provide a method for producing an Fe-based amorphous ribbon capable of obtaining a nanocrystalline material having excellent magnetic properties, and a method for producing a nanocrystalline soft magnetic material using the same.

[0006]

Means for Solving the Problems The present inventors set B to 10
mol% or less, at least one element of the group 4A, 5A, or 6A was contained in an amount of 15 mol% or less, and the balance was substantially investigated. Found that air bubbles were formed in the hollow part called the air pocket generated on the roll contact surface side of the ribbon, and studied to prevent the generation of crystals generated in this air pocket, and introduced a gas with a large heat capacity. Has been found to be effective in suppressing the generation of crystals during casting, and has reached the present invention.

That is, according to the present invention, a constant pressure specific heat at 30 ° C. is applied to a molten metal containing B of 10 mol% or less and at least one element of the 4A, 5A, and 6A groups of 15 mol% or less and the balance substantially consisting of Fe. Is 32 J / mol
A method for producing an amorphous ribbon for a nanocrystalline material, which comprises pouring a molten metal into a moving cooling body while introducing a gas of K or more. More preferably, the gas has a constant pressure specific heat at 30 ° C. of 35 J / mol · K or more.

[0008] The nanocrystalline material of the present invention means a material having a structure having an average particle diameter of 100 nm or less. In addition, from the viewpoint of the ability to form an amorphous phase and magnetic properties, the molten metal contains 5 to 30 mol% of an element such as C or Si as a metalloid element other than B, and 70 mol% of Fe as a main component.
As described above, Cu, Ag, A
It is desirable that at least one element of u be contained in an amount of 3 mol% or less, more preferably 0.1 mol% or more.

[0009] The amorphous ribbon for nanocrystals produced by the above-described method is heat-treated at a temperature higher than the crystallization temperature to form a nanocrystal structure having an average crystal grain size of 100 nm or less. Obtainable.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, an important feature of the present invention is that a gas having a large heat capacity, that is, a gas having a large specific heat is applied when casting an amorphous ribbon for nanocrystals. According to the studies by the present inventors, the air pockets are rapidly formed when the air accompanying the surface of the cooling roll enters the boundary layer between the molten metal pool (hereinafter referred to as “paddle”) and the cooling roll. Although it is caused by the expansion, the portion where the air pocket is generated does not adhere to the cooling roll, so that the cooling speed is considered to be extremely slow. The present invention suppresses the temperature rise of the gas present between the air pocket and the roll by introducing a gas having a large heat capacity, thereby increasing the cooling rate of the portion where the air pocket is generated, and forming a precursor of the nanocrystalline material. Can suppress the inclusion of crystals partially during casting.

Hereinafter, the present invention will be described in detail.
In the present invention, that the constant pressure specific heat _{C P} at 30 ° C. of the atmospheric gas is greater than 32 J / mol · K is
Since the temperature is hardly increased even if the ribbon is caught in the paddle, it is very effective to increase the cooling speed of the air pocket portion of the ribbon (the speed of removing heat from the molten metal by the moving cooling body). 30 ° C
If the specific heat at constant pressure is less than 32 J / mol · K, a crystalline phase is generated in the manufactured amorphous ribbon, particularly in the air pocket portion, such that the magnetic properties of the nanocrystalline material after the heat treatment are significantly deteriorated. CO _2, CO at a constant pressure specific heat at 30 ° C. of 32 J / mol · K or more
A mixed gas of ₂ and N ₂ , Ar, etc., SO _2, NO _X gas and the like can be cited. Among them, CO ₂ gas is relatively safe and low cost, and is industrially effective.

The reason why B is set to 10 mol% or less is as follows.
If the amount of B is extremely large, a magnetically hard compound phase such as Fe ₃ B or Fe ₂ B which hinders the movement of the magnetic domain wall is likely to be precipitated during the heat treatment, and a uniform nanocrystal having a bcc-Fe solid solution as a main phase. This is because it is difficult to obtain a phase. For this reason, the amount of B contained in the Fe-based amorphous alloy for the nanocrystalline material is preferably 10 mol% or less from the viewpoint of magnetic properties. The group 4A, 5A, and 6A elements described in the present invention include Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W.
Means These elements are concentrated in the amorphous phase remaining around the generated bcc-Fe crystal phase when the amorphous ribbon is heat-treated at a crystallization temperature or higher, and stabilize the remaining amorphous phase. It is essential to suppress growth. One of these elements
The reason for setting the content to 5 mol% or less is that if the content exceeds 15 mol%, the ribbon becomes brittle and becomes difficult to handle. These elements have different effects of suppressing bcc-Fe crystal grains, but a more preferable range is 1 to 10 mol%.

Further, Cu, Ag, and Au are 4A, 5A,
The combined addition with the Group 6A element increases the number of primary crystal nuclei when heat-treated at a crystallization temperature or higher, and thus has the effect of refining crystal grains as a nanocrystalline material. 3 mol of at least one of Cu, Ag and Au
% Or less because if it exceeds 3 mol%, the ribbon becomes brittle. Further, Cu, Ag, and Au are elements that are easily separated from Fe. If the amount is too large, it is separated from Fe even if the liquid quenching method is used, and the solid solution cannot be uniformly formed. % Or less is good. In order to clearly obtain the effects of these elements, preferably,
0.1 mol% or more is added.

Further, as the moving cooling body described in the present invention, a member capable of securing a moving cooling surface such as a rotating cylindrical roll or a moving belt can be used. From the viewpoints of properties, maintenance, and the like, it is preferable to apply a single roll method using one rotating cylindrical roll. The material of the roll is Cu,
A material having a high thermal conductivity such as a Cu-Be alloy or a Cu-Cr alloy is preferable. Further, when a liquid such as water flows in the inside of the roll in the circumferential direction or the axial direction of the roll, the temperature of the roll surface can be more easily adjusted.

[0015] The nanocrystalline material is obtained by heat-treating an amorphous ribbon produced by a single roll method or the like at a crystallization temperature or higher. However, when heat-treated in the air, the surface is oxidized and the magnetic properties after the heat treatment deteriorate. To do
It is better to carry out in an atmosphere with little oxygen such as nitrogen and argon.

[0016]

(Example 1) 0.9 Cu-3Nb in mol%
A ribbon having a composition of -15.5Si-7B and the balance substantially consisting of Fe was produced. The apparatus used for ribbon production is shown in FIG. An ingot having the above-mentioned composition previously melted was placed in the crucible 2 in the drawing, and heated and melted by the high-frequency coil 6,
Molten metal is ejected from a nozzle 1 onto a rotating cooling roll 3 made of a Cu-Be alloy, rapidly solidified, and has a width of 25 mm.
An amorphous ribbon having a thickness of 20 μm was manufactured. During production, the temperature of the cooling roll surface was 200 ° C, and A
Ar, N ₂ is mixed with r, N ₂ , air, CO ₂ and CO ₂ , and the specific heat at a constant pressure at 30 ° C. is 20 to 40 J / mo.
The ribbon was manufactured while flowing a gas having a range of 1 · K from the nozzle 7. The produced ribbon was peeled and recovered by ejecting gas from the peeling nozzle 5 in FIG. 1 in a direction opposite to the rotation direction of the roll.

The evaluation was performed on the ribbon 30 minutes after the start of casting, and the precipitation peak intensity of the crystal phase on the cooling roll contact surface side and the magnetic properties after the heat treatment were evaluated. The precipitation peak intensity of the crystal phase was determined by using an X-ray diffractometer and using α-Fe (2
00) Determined by peak intensity. The magnetic properties were measured by measuring the relative initial magnetic permeability μ of the ribbon having the above-mentioned size after heat-treating a toroidal core having an outer diameter of 19 mm and an inner diameter of 15 mm at 530 ° C. for 1 hour. However, the measurement frequency was set to 10 kHz because the influence of the surface roughness of the ribbon was large at a low frequency.

The results are shown in FIGS. Figures 2, 3 and 3
A gas having a higher specific heat per 1 mol at 0 ° C. is more difficult to crystallize and has a frequency of 10 k after heat treatment.
The μ at Hz also increased, and a high μ exceeding 80,000 was obtained by applying a gas having a specific heat at a constant pressure of 30 J / mol · K or more at 30 ° C. 2 and 3, a toroidal shape having an outer diameter of 19 mm and an inner diameter of 15 mm was obtained from a ribbon to which a gas having a specific heat during casting of 21 J / mol · K was applied and a ribbon to which a gas having a specific heat of 32.5 J / mol · K was applied. A core was prepared, and μ at a frequency of 10 kHz was measured. As a result, it was 410, 32 for 21 J / mol · K.
J / mol · K was almost equal to 370.
On the other hand, μ after the heat treatment was 21 J /
50500 for mol · K and 85,000 for 32 J / mol · K. Therefore, it is clear that the crystal phase generated at the time of casting has a greater effect on the magnetic properties after the heat treatment than as-cast.

In FIG. 2, a ribbon produced at a specific heat of less than 32 J / mol · K at which a crystal phase was deposited on the roll contact surface side was observed with a transmission electron microscope.
As shown in FIG. 4, a dendrite-like crystal phase having a particle size exceeding 100 nm was observed in the air pocket portion. Furthermore, when the structure after the heat treatment was also observed, 32 J / m
The ribbon produced by flowing a gas of ol · K or more had a uniform structure with an average particle diameter of 50 nm or less, but was 32 J / mo.
In each of the ribbons produced while flowing a gas of less than 1 · K, a large number of crystal grains exceeding 100 nm were observed, and the ribbon had an uneven structure.

Example 2 A ribbon having the composition shown in Table 1 was manufactured using the same apparatus as that shown in FIG. A crucible is charged with an ingot of the above-mentioned composition previously melted and melted by high-frequency induction heating, and then a molten metal is jetted onto a cooling roll made of a Cu-Be alloy, rapidly cooled and solidified, and has a width of 40 mm and a thickness of 20 μm. Was manufactured. During the production, the temperature of the cooling roll surface was set to 190 ° C, and CO
₂ and N _2, and the constant pressure specific heat at 30 ° C. is 35 J /
A ribbon was produced while blowing a gas of mol · K in the vicinity of the paddle.

The evaluation was performed on a ribbon 20 minutes after the start of casting, and the presence or absence of a crystal phase precipitation peak on the cooling roll contact surface side and the magnetic properties after heat treatment were evaluated. As for the magnetic characteristics, the core having an outer diameter of 19 mm and an inner diameter of 15 mm was cooled after maintaining the heat treatment temperature at 500 to 600 ° C. for 1 H, and the maximum value of the relative initial magnetic permeability μ at a frequency of 10 kHz was determined. As a result, no precipitation peak of the crystal phase was observed in any of the ribbons before the heat treatment. However, μ at 1 kHz is 80 for a ribbon having a composition within the range of the present invention.
B11mo, where high values of 000 to 130000 were obtained
With 1% ribbon, only a very small value of 11,000 was obtained. When the ribbon after the heat treatment was observed with a transmission electron microscope, all of the ribbons had an average particle diameter of 100 nm.
It was below.

[0022]

[Table 1]

(Embodiment 3) Using the same apparatus as in FIG.
ol%, 1.1Cu-3Nb-Zr0.1-15.2
A ribbon having a composition consisting of Si-8.5B and the balance substantially consisting of Fe was produced. A crucible is charged with an ingot of the above composition previously melted and melted by high-frequency induction heating.
A molten metal was jetted onto a cooling roll made of a Be alloy and rapidly solidified to produce an amorphous ribbon having a width of 18 mm and a thickness of 19 μm. The temperature of the cooling roll surface during production was 195.
℃, constant pressure specific heat at 30 ℃ near the paddle is 37J
/ Mol · K CO ₂ gas was blown to produce a ribbon.

Using a ribbon 25 minutes after the start of casting, evaluation was made on the presence or absence of a precipitation peak of the αFe crystal phase on the cooling roll contact surface side and the magnetic properties after heat treatment. The precipitation peak of the crystal phase was evaluated using an X-ray diffractometer. The magnetic characteristics were as follows. A magnetic core having an outer diameter of 19 mm and an inner diameter of 15 mm was cooled at a heat treatment temperature of 540 ° C. for 1 H, and cooled at a frequency of 1 k.
The evaluation was made based on the specific initial magnetic permeability μ at Hz. As a result, no peak indicating the precipitation of a crystal phase was observed in the ribbon before the heat treatment. Further, μ after the heat treatment was 83200, which was a practically sufficient value. Furthermore, when the ribbon after the heat treatment was observed with a transmission electron microscope, it was a uniform structure having an average particle diameter of 100 nm or less.

(Embodiment 4) Using the same apparatus as in FIG.
A ribbon having a composition consisting of 7Nb-9B at ol% and the balance substantially consisting of Fe was produced. A crucible was charged with an ingot of the above-mentioned composition previously melted and melted by high-frequency induction heating, and then a molten metal was jetted onto a cooling roll made of a Cu-Be alloy, rapidly cooled and solidified to a width of 7 mm and a thickness of 19 μm. Was manufactured. During the production, the temperature of the cooling roll surface was set to 185 ° C., and a mixed gas of CO ₂ and Ar having a specific heat at a constant pressure of 33 J / mol · K at 30 ° C. was sprayed immediately near the paddle.

The evaluation was made on the presence or absence of a precipitation peak of the αFe crystal phase on the cooling roll contact surface side of the ribbon 30 minutes after the start of casting, and the magnetic properties after heat treatment. The precipitation peak of the crystal phase was evaluated using an X-ray diffractometer, and the magnetic properties of the wound core having an outer diameter of 20 mm and an inner diameter of 16 mm were kept at a heat treatment temperature of 650 ° C. for 3 hours, then cooled, and the magnetic field strength was 0.4 A / m. The evaluation was performed using μ at a frequency of 1 kHz.
As a result, no peak indicating the precipitation of a crystal phase was observed in the ribbon before the heat treatment. Μ after the heat treatment is 4950
It was 0. Furthermore, when the ribbon after the heat treatment was observed with a transmission electron microscope, it was a uniform structure having an average particle diameter of 100 nm or less.

[0027]

According to the present invention, an Fe-based amorphous ribbon for a nanocrystalline material having excellent magnetic properties can be continuously formed without precipitation of a crystal phase which is very harmful to the magnetic properties after heat treatment and without breakage during manufacturing. The industrial value is great because it can be manufactured stably.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of an apparatus for performing a manufacturing method of the present invention.

FIG. 2 is a diagram showing a relationship between specific heat of a gas used and a crystal phase peak intensity on a roll contact surface side of a ribbon.

FIG. 3 is a diagram showing a relationship between specific heat of a gas used and magnetic characteristics.

FIG. 4 is a transmission electron micrograph of an air pocket portion on a roll contact surface side of an as-cast ribbon in a comparative example.

[Explanation of symbols]

1 nozzle, 2 crucible, 3 cooling roll, 4 ribbon,
5 peeling nozzle, 6 high frequency coil, 7 gas nozzle

 ──────────────────────────────────────────────────続 き Continued from the front page F term (reference) 4E004 DB02 TA01 TA03 TB02 TB04 5E041 AA11 AA19 BD00 BD03 CA01 HB07 HB11 HB19 NN01 NN17

Claims (3)

[Claims] 1. The method according to claim 1, wherein B is 10 mol% or less, 4A, 5A, 6
15 ° C. or less containing at least one or more elements of Group A, and the remaining 30 ° C.
3. A method for producing an amorphous ribbon for a nanocrystalline material, comprising pouring a molten metal into a moving cooling body while introducing a gas having a specific heat at a constant pressure of 32 J / mol · K or more. 2. The method for producing an amorphous ribbon for a nanocrystalline material according to claim 1, wherein at least one element of Cu, Ag, and Au is contained in an amount of 3 mol% or less. 3. A nanocrystalline soft magnetic material, wherein the amorphous ribbon produced by the method according to claim 1 is heat-treated at a crystallization temperature or higher to form a nanocrystalline structure having an average crystal grain size of 100 nm or less. Material manufacturing method.