JPH03107417A - Production of supermicrocrystalline soft magnetic alloy - Google Patents

Abstract

PURPOSE:To produce the supermicrocrystalline soft magnetic alloy which exhibits a low loss or high pulse inductivity by subjecting an amorphous alloy contg. Fe, Cu and Nb, etc., to a heat treatment at a Curie temp. or above, then to heat treatment in a magnetic field at the above-mentioned heat treatment temp. or below. CONSTITUTION:The alloy if the compsn. contg. Fe, Cu and M (M is at least one kind of Nb, W, Ta, Zr, Ht, Ti, and Mo) as its essential components is treated by a liquid rapid cooling method, such as single roll method or gaseous phase rapid cooling method, etc., such as sputtering method, to obtain the amorphous alloy. This alloy is heated to form the supermicrocrystal grains. The alloy is subjected to the heat treatment at the Curie temp. of the crystal phase to te formed or above at this time. The above-mentioned alloy is thereafter subjected to the heat treatment in the magnetic field while the magnetic field is impressed thereto at the temp. below the above-mentioned heat treatment temp. The first heat treatment may otherwise be executed in the rotating magnetic field at the Curie temp. or below and the next heat treatment may be executed by the heat treatment in the magnetic field while the magnetic field is impressed to the alloy in a specific direction at the Curie temp.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing an ultrafine crystalline soft magnetic alloy that exhibits particularly low loss at a high squareness ratio, or particularly high pulse permeability at a low squareness ratio. be.

[Prior art] Conventionally, 50 wt% Ni permalloy alloy and 80 wt% N have been used as alloys for saturable reactors that require characteristics of high squareness ratio.
i-permalloy alloys and CO-based amorphous alloys were mainly used. However, 50wt% permalloy has a problem in that it has a large magnetic core loss at high frequencies and generates a large amount of heat at high frequencies, particularly at frequencies exceeding 20kllz, making it difficult to use. 80wt% Ni permalloy has problems such as insufficient squareness and insufficient controlled magnetization characteristics in a frequency band exceeding 100kHz. CO-based amorphous alloys are suitable for high frequency applications because they have a high squareness ratio and low loss characteristics, but they have a problem that the operating magnetic flux density cannot be sufficiently increased because the saturation magnetic flux density is not high enough.

On the other hand, as alloys with a low squareness ratio suitable for common mode chokes, current transformers, etc., are isoperm alloys, fluorite, elite, Co-based amorphous alloys heat-treated in a vertical magnetic field, etc. are known.

However, isoperm alloys and ferrites have problems such as insufficient pulse permeability, and Co-based amorphous alloys have problems such as large changes over time and low saturation magnetic flux density, which limits the ability to make parts smaller and improve performance. be.

The present inventors have previously reported that Fe-based ultrafine-crystalline alloys are suitable for these uses as a solution to these drawbacks. (Refer to JP-A No. 01-79342, etc.).

Furthermore, as a method for manufacturing an ultrafine crystalline soft magnetic alloy that exhibits characteristics suitable for these uses, we have applied for a method in which heat treatment to form ultrafine crystal grains is followed by heat treatment in a magnetic field while applying a magnetic field.

[Problems to be solved by the invention] However, in order to make parts using the above-mentioned ultrafine-crystalline soft magnetic alloy more compact and high-performance in the high frequency range, it is necessary to further improve the characteristics, that is, to increase the squareness ratio. Characteristics of lower loss, lower squareness ratio and higher pulse permeability are required. However, with conventional manufacturing methods, when attempting to maintain a high squareness ratio and reduce core loss, the squareness ratio inevitably decreases, making stable production difficult. When trying to obtain magnetic properties, conventional manufacturing methods often result in a large squareness ratio, especially when trying to obtain high magnetic permeability. As described above, it has been difficult to stably obtain a high squareness ratio and low core loss using conventional manufacturing methods.

[Means for Solving the Problems] As a result of intensive studies to achieve the above object, the present inventors have determined that Fe, Cu and M (where N is Nb, JTa,
Zr.

A method for producing an ultrafine crystalline soft magnetic alloy containing at least one element selected from the group consisting of Hf, Ti, and Mo as an essential element and in which at least 50% of the structure consists of fine crystal grains, After producing a crystalline alloy and performing heat treatment to form ultrafine crystal grains by heating it at a temperature higher than the Curie temperature of the crystal phase to be formed, a magnetic field is further applied at a temperature lower than the heat treatment temperature. By using a manufacturing method that performs heat treatment in a magnetic field, it is possible to prevent unnecessary induced magnetic anisotropy from occurring, to form induced magnetic anisotropy only in a specific direction, and to control its magnitude. The inventors have discovered that it is possible to obtain an alloy with a particularly low loss at a high squareness ratio, and an alloy with a particularly high pulse permeability at a low squareness ratio, and to reduce the variation thereof, and have conceived the present invention.

Another aspect of the present invention includes Fe, Cu, and M (where H is at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti, and Mo) as essential elements, and contains at least 50% of the structure. % of ultrafine crystalline soft magnetic alloys, in which an amorphous alloy having the above composition is prepared, and the crystalline phase is heated to form ultrafine crystal grains. An ultrafine-crystalline soft magnetic alloy characterized in that it is heat-treated in a rotating magnetic field at a temperature below the Curie temperature of the crystal phase, and then further heat-treated in a magnetic field while applying a magnetic field in a specific direction at a temperature below the Curie temperature of the crystalline phase. This is a manufacturing method, and it is possible to easily obtain an alloy that exhibits the same excellent magnetic properties as the aforementioned manufacturing method.

The heat treatment in a magnetic field performed after the heat treatment for forming fine crystals may be performed by just a cooling process, or may be performed by cooling without a magnetic field and then heating while applying a magnetic field again. Further, although the heat treatment for crystallization may be performed subsequently, more preferable results can be obtained by applying a magnetic field during the cooling process and performing the heat treatment in the magnetic field. When the direction of application of the magnetic field is in the direction of the magnetic path of the magnetic core, a high squareness ratio and low core loss characteristics can be obtained. On the other hand, when the magnetic field application direction is perpendicular to the magnetic path, characteristics of high magnetic permeability with a low squareness ratio can be obtained. The reason why it is better to perform heat treatment to form fine crystal grains at a temperature higher than the Curie temperature of the crystal phase forming it is as follows.
By performing heat treatment above the Curie temperature, induced magnetic anisotropy is prevented from occurring locally in undesirable directions before heat treatment in a magnetic field, and induced magnetic anisotropy is prevented only in the direction of application of the magnetic field after heat treatment in a magnetic field. This is thought to be because it makes it easier to attach.

Therefore, high squareness ratio and low squareness ratio characteristics can be obtained with only a slight anisotropy caused by heat treatment in a magnetic field, and a state with small induced magnetic anisotropy can be achieved, resulting in high squareness ratio and low core loss. It is thought that characteristics of low squareness ratio and high pulse permeability can be realized. For the same reason, when heat treatment is performed in a rotating magnetic field to form fine crystal grains and then a magnetic field is applied in a specific direction, a high squareness ratio results in low core loss and a low squareness ratio results in high pulse transmission. It is thought that magnetic properties can be obtained.

Here, the heat treatment in a rotating magnetic field is a method of heat treating the object to be heat treated by changing the direction of the magnetic field with time.
This can be done by rotating the object to be heat treated in a magnetic field fixed in a fixed direction, or by performing heat treatment while rotating the magnetic field. As described above, in the manufacturing method of the present invention, it is possible to prevent the formation of locally undesirable induced magnetic anisotropy during heat treatment for crystallization.
Variability is also reduced. The alloy produced according to the present invention has the following general formula: % formula % () At least one element selected from Au, X' is Nb,
W.

At least one element selected from the group consisting of Ta, Zr, Iff, Ti, and Mo; M'' is V, Cr, Mn,
AI, platinum group element.

At least one element selected from the group consisting of Sc, Y, Zn, Sn, Re, X is C, Ge, P, Ga, Sb,
At least one selected from the group consisting of In, Be, and As
It is a species element, a.

x, y, z, a, β and γ each satisfy O≦a≦0.
5, 0.1≦x≦3, 0≦y≦30, 0≦Z≦25,5
≦y+z≦30.0.1≦α≦30゜0≦β≦10,0
≦γ≦10 is satisfied. ) It is easy to obtain preferable results with an alloy having a composition represented by: The amorphous alloy according to the present invention can be produced by various methods such as a liquid quenching method such as a single roll method or a twin roll method, or a vapor phase quenching method such as a sputtering method or a vapor deposition method.

[Example] The present invention will be described below with reference to Examples, but the present invention is not limited thereto.

Example 1 Cu1%, Nb4%, 5i13.5%, B9% in atomic%
A molten alloy having a composition in which the remainder substantially consisted of Fe was rapidly cooled by a single roll method to produce an amorphous alloy ribbon having a width of 10 mm and a thickness of 17 μm. Next, this alloy ribbon was wound to have an outer diameter of 19 mm and an inner diameter of 15 mm, and heat treatment was performed in accordance with the heat treatment pattern shown in Figures 1 and 2 in the section after preparing a toroidal magnetic core. FIG. 1 shows an example of a heat treatment pattern according to the present invention, and FIG. 2 shows an example of a conventional heat treatment pattern. As a result of structural observation using X-ray diffraction and transmission electron microscopy, it was confirmed that the alloy after heat treatment consisted of an ultrafine crystal grain structure with a grain size of 100 to 200 grains. Magnetic flux density BIO1 squareness ratio Br/B of alloy after heat treatment at 100e
The pulse magnetic core loss at IO 1100 kHz, Bm = 2 kG, and the pulse magnetic permeability μp at pulse width 100 μs1 and B = 2 kG were measured. The magnetic properties of the alloy after heat treatment are shown in Table 1.

When the heat treatment pattern according to the present invention is applied and a magnetic field is applied in the direction of the magnetic path, the squareness ratio is high (lower magnetic core loss than the conventional method), and when the magnetic field is applied in the direction perpendicular to the magnetic path, the squareness ratio is high. With this method, a pulse permeability μp higher than that of the conventional method can be obtained.

Table 1 Example 2 Cu1.2%, Nb3%, 5i13.8%, 8 in atomic %
A molten alloy having a composition essentially consisting of 8.8% Fe was rapidly cooled by a single roll method to produce an amorphous alloy ribbon having a width of 5 mm and a thickness of 16 μm. Heat treatment was performed using the heat treatment pattern of (Comparative Example), and the magnetic properties were measured. The direction of the magnetic field applied during the heat treatment in the magnetic field after the heat treatment in the rotating magnetic field was the longitudinal direction of the ribbon. The structure of the alloy after heat treatment consisted of fine crystal grains with a grain size of 100 to 200 grains, similar to Example 1.

In the case of the manufacturing method of the present invention, Br/B10=95% and a core loss of 360 mW/cc were obtained, which is inferior to the present invention.

On the other hand, with the conventional method, Br/BlO 90% and a core loss of 560 mW/cc were obtained, indicating that the method of the present invention is effective in achieving a high squareness ratio and low core loss.

Example 3 A molten alloy having the composition shown in Table 2 was rapidly cooled by a single roll method, and heat treated according to the heat treatment pattern shown in FIGS. 3 and 4. After the heat treatment in the rotating magnetic field, the direction of application of the magnetic field was in the width direction of the ribbon.

11-Table 12- The alloy after heat treatment had the same microstructure as Example 1.

Table 2 shows the range of variation in magnetic properties under each of the 10 conditions measured after heat treatment.

It can be seen that manufacturing according to the present invention is preferable because it is easier to obtain a high pulse permeability and a low squareness ratio, and the variation is small.

[Effects of the Invention and Ideas] According to the present invention, it is possible to produce an ultrafine crystalline soft magnetic alloy with a higher squareness ratio and lower loss or a lower squareness ratio and higher pulse permeability than before, and the variation can be reduced. There are some notable ones.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of a heat treatment pattern according to the present invention;
FIG. 2 is a diagram showing an example of a conventional heat treatment pattern, FIG. 3 is a diagram showing another example of a heat treatment pattern according to the present invention, and FIG. 4 is a diagram showing another example of a conventional heat treatment pattern. be. 1st Time (a) Time (C) (b) Time (e) Time (a) Diagram time diagram Time (b) Diagram time

Claims (4)

[Claims] (1) Fe, Cu and M (where M is Nb, W, Ta
, Zr, Hf, Ti and Mo) as an essential element, and at least 50% of the structure consists of fine crystal grains. After producing an amorphous alloy with the same composition and performing heat treatment to form ultrafine crystal grains at a temperature higher than the Curie temperature of the crystal phase to be formed,
A method for producing an ultrafine-crystalline soft magnetic alloy, further comprising performing heat treatment in a magnetic field while applying a magnetic field at a temperature below the heat treatment temperature. (2) Fe, Cu and M (where M is Nb, W, Ta
, Zr, Hf, Ti and Mo) as an essential element, and at least 50% of the structure consists of fine crystal grains. After producing an amorphous alloy with the same composition and performing a heat treatment to form ultrafine crystal grains at a temperature below the Curie temperature of the crystalline phase and in a rotating magnetic field, the crystalline phase is further heated. A method for producing an ultrafine-crystalline soft magnetic alloy, which comprises performing heat treatment in a magnetic field while applying a magnetic field in a specific direction at a temperature below the Curie temperature. (3) The method for producing an ultrafine-crystalline soft magnetic alloy according to claim 1, characterized in that the heat treatment in the magnetic field is performed by applying a magnetic field only during the cooling process of the heat treatment. (4) The alloy has the general formula: (Fel-aMa)100-x-y-z-α-β-γA
xSiyBzM'αM''βXγ(at%) (However, M is Co and/or Ni, A is Cu,
At least one element selected from Ag, Au, M' is at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti, and Mo, M'' is V, Cr,
Mn, Al, platinum group elements, Sc, Y, Zn, Sn, Re
at least one element selected from the group consisting of, x is C
, Ge, P, Ga, Sb, In, Be, As, at least one element selected from the group consisting of a, x, y
, z, α, β and γ are 0≦a≦0.5, 0.1, respectively
≦x≦3, 0≦y≦30, 0≦z≦25, 5≦y+z≦
30, 0.1≦α≦30, 0≦β≦10, 0≦γ≦10
satisfy. ) The method for producing an ultrafine-crystalline soft magnetic alloy according to any one of claims 1 to 3, characterized in that it has a composition represented by: