JPH01242755A - Fe-based magnetic alloy - Google Patents

Abstract

PURPOSE:To obtain a magnetic alloy having low core loss, high magnetic permeability and small characteristic deterioration caused by strain, etc., by compositely adding specific ratios of Cu and one or more kinds of other specific elements to an alloy contg. Fe and B as basic components. CONSTITUTION:The Fe-based magnetic alloy is formed with the compsn. expressed by formula I. The formula I is shown by atom%, and M denotes Co and/or Ni, A denotes Cu and/or Ag, M' denotes one or more kinds of elements selected from Nb, Ta, Zr, Hf, Ti and Mo. In the formula, 0<=a<=0.3, 0.1<=x<=10, 1<=alpha<=30 and 5<=z<=17 are furthermore satisfied. At least 50% of the structure is regulated to fine crystal grains and the average grain size of the grain size measured by the maximum size is regulated to <=1,000Angstrom . The alloy having the compsn. expressed by formula II can furthermore be applied. In the formula II, M'' is selected from V, Cr, Mn, the platinum group, Au, etc., and beta is regulated to <=10. The Fe-based magnetic alloy has excellent soft magnetic characteristics and has the characteristics of low magnetostriction, etc.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a high frequency transformer and a choke coil.

The present invention relates to an Fe-based magnetic alloy having an ultrafine grain structure that exhibits good soft magnetism and is suitable for magnetic core materials such as magnetic heads.

[Prior Art] Conventionally, as magnetic core materials for high frequency transformers, choke coils, magnetic heads, etc., ferrite, which has the advantage of low eddy current product, silicon steel, permalloy, Fe-Al!, which has the feature of high saturation magnetic flux density, and other materials have been used. , -Si alloy, etc. were used.

However, since ferrite has a low saturation magnetic flux density and poor temperature characteristics, it has the disadvantage that it is difficult to miniaturize the magnetic core when used in high frequency transformers and choke coils. Although silicon steel has a high saturation magnetic flux density, it has poor high-frequency magnetic properties and has the problem of increasing heat generation due to core loss in the high-frequency range. Although permalloy is a relatively well-balanced material, it has the disadvantage that its soft magnetic properties deteriorate significantly due to impact or deformation. The Fe-Al1-Si alloy is
Because it is brittle, it is difficult to make it into a thin sheet, and it can only be made into a thin sheet by ultra-quenching. However, it is extremely difficult to fabricate a broken wedge-wound magnetic core when tension is applied because the embrittlement is significant. Further, even when the film is made thinner, there are problems in that the coefficient of thermal expansion is large and the properties deteriorate and the film is easily peeled off.

In recent years, amorphous alloys have attracted attention and some have been put into practical use as materials that can improve these drawbacks to some extent.

Amorphous alloys are mainly divided into Fe-based and Co-based.
The amorphous alloy of the system has a high saturation magnetic flux density and the material cost is C
Although it has the advantage of being cheaper than the Co-based amorphous alloy, it has the problem of having a larger core loss and lower magnetic permeability than the Co-based amorphous alloy at high frequencies for boat fishing. In addition, the ree amorphous alloy has extremely large magnetostriction, and when used together as a magnetic core, the magnetic core generates beats, and when impregnated, coated, etc., the characteristics deteriorate significantly.

On the other hand, Co-based amorphous alloys have small core loss at high frequencies and high magnetic permeability, but have the drawbacks of large changes in core loss and magnetic permeability over time, and insufficient saturation magnetic flux density. Furthermore, since expensive Co is used as the main raw material, it is inevitably disadvantageous in terms of price.

Under these circumstances, various proposals have been made regarding Fe-based amorphous alloys.

Japanese Patent Publication No. 60-17019 states that 74 to 84 atomic% of F
e, at least one of 8 to 24 atomic % B, 16 atomic % or less Si, and 3 atomic % or less C, and at least 85% of its structure is an amorphous metal substrate. and has precipitates of crystalline particles distributed discontinuously throughout the amorphous metal matrix,
The crystalline particles have an average particle size of 0.05 to 1 μm and 1 to 1
An iron-based boron-containing magnetic amorphous alloy is disclosed, which has an average interparticle distance of 0 μm, and the particle groups occupy an average volume fraction of 0.01 to 0.3 of the whole. ing.

The crystalline particles of this alloy are said to be discontinuously distributed α-(Fe, Si) particles that act as pinning points of the domain wall.

Also, in JP-A-60-52557, Fe, Cub B
cSja (however, 75≦a≦85.Orb≦0.5
, 10°≦C≦20, d≦10 and c+d≦30). This amorphous alloy is heat treated below the crystallization temperature and above the Curie temperature.

[Problem that the invention seeks to solve]

In the magnetic core made of the Fe-based magnetomagnetic alloy disclosed in Japanese Patent Publication No. 60-17019, the core loss is reduced due to the presence of discontinuous crystalline grain groups, but the core loss is still large, and in particular, the core loss is large, causing beats. However, impregnation coating causes core loss and significant deterioration of magnetic permeability, and cut cores and the like have not been able to provide high properties.

On the other hand, the Fe-based amorphous alloy of JP-A No. 60-52557 contains Cu, and the core loss of the magnetic core using it is reduced, but it is similar to the core loss of the magnetic core using the Fe-based magnetic alloy containing crystal grains. Not satisfied with that. Furthermore, there are problems in terms of changes in core loss over time and magnetic permeability.

Therefore, the purpose of the present invention is to achieve low core loss, high magnetic permeability,
It is an object of the present invention to provide an Fe-based magnetic alloy whose characteristics are less deteriorated due to strain and the like, and to provide a method for manufacturing the same.

[Means for Solving the Problems] In view of the above objectives, as a result of intensive research, the present inventors added Cu to an alloy whose basic components are Fe and B, which is an amorphous forming element.
By adding at least one element selected from Nb, W, Ta, Zr, ■f, Ti, and Mo in combination, appropriate heat treatment of the amorphous alloy results in a Fe-based structure in which the majority of the structure is composed of fine crystal grains. A magnetic alloy is obtained, and further,
It was discovered that a magnetic core using this alloy exhibits excellent characteristics, and the present invention was conceived.

The Fe-based magnetic alloy of the present invention has the general formula: % formula % () (where M is CO and/or Ni, A is Cu and/or 8g, and M' is Nb, W, Ta,
Zr, Hf.

At least one element selected from the group consisting of Ti and Mo, a, x, y, α, and 2 are each,
0≦a≦0.3, 0.1≦X≦10.5≦2≦17.1
≦α≦30 is satisfied. ), at least 50% of the structure consists of fine crystal grains, and the crystal grains have an average grain size of 1000 Å or less.

The Pe-based magnetic alloy according to the present invention can also be obtained by a step of rapidly cooling the amorphous alloy and a heat treatment step of heating it to form fine crystal grains.

In the alloy used in the present invention, Cu and/or Ag
is an essential element, and its content X is 0.1 to 10 at%
is within the range of If it is less than 0.1 atomic%, Cu, A
This is because the addition of g has almost no effect of reducing core loss or increasing magnetic permeability, while if it is more than 10 atomic %, it causes a decrease in saturation magnetic flux density and deterioration of soft magnetic properties. In the present invention, the particularly preferable content X of Cu and/or Ag is 0
．． The core loss is particularly small and the magnetic permeability is high in this range.

The cause of the core loss reduction and magnetic permeability increase effect of Cu + Ag is not clear, but it is thought to be as follows.

The interaction parameter between Cu, Ag and Fe is positive, their solid solubility is low, and they tend to separate, so when an amorphous alloy is heated, Fe atoms or Cu + Ag atoms come together to form clusters. This causes compositional fluctuations. For this reason, there are many regions that are easily crystallized locally, and fine crystal grains are generated with these regions as nuclei. This crystal has Fe as its main component, and Fe and Cu
, Since Ag has almost no solid solubility, Cu crystallizes.
, Ag is expelled around the fine crystal grains, and the Cu and Ag concentrations around the crystal grains increase. Therefore, it is considered that crystal grains are difficult to grow.

It is thought that crystal grain refinement occurs due to the formation of a large number of crystal nuclei and the difficulty in grain growth due to the addition of Cu and Ag, but this effect is caused by Nb, Ta, W, Mo, and Z.
r.

It is thought that the presence of If, Ti, etc. makes this particularly significant.

Nb, Ta, W, Mo, Zr, Hf, Ti
If these are not present, the crystal grains will not be made much finer and the soft magnetic properties will be poor. Nb and Mo are particularly effective, but when Nb is added among these elements, crystal grains tend to become thinner, and products with excellent soft magnetic properties can be obtained.

In addition, since a fine crystal phase mainly composed of Fe is generated, the magnetostriction is smaller than that of Fe-based amorphous alloys, and the magnetic anisotropy due to internal window Kerr strain is also reduced, which is thought to be the reason why the soft magnetic properties are improved. It will be done.

If Cu or Ag is not added, crystal grains are difficult to refine (and because compound phases are likely to form, magnetic properties often deteriorate due to crystallization.

B is a particularly useful element for refining the alloy according to the present invention. The Fe-based magnetic alloy according to the present invention, preferably -
It is obtained by forming an amorphous alloy due to the effect of adding B and then forming fine crystal grains by heat treatment. The reason for limiting the B content z is that it is difficult to obtain soft magnetic properties unless 2 is 17 atomic % or less.

In the present invention, M' has the effect of refining the crystal grains precipitated by the combined addition with Cu + Ag, and M' is at least one selected from the group consisting of Nb, W, Ta, Zr, Hf + Tt, and MO. It is a type of element.

Nb etc. have the effect of increasing the crystallization temperature of the alloy and making it easier to become amorphous, but the crystal grains that precipitate due to interaction with Cu + Ag, which has the effect of forming clusters and lowering the crystallization temperature. It is thought that it will become finer. M
The content α of ' is 1 to 30 atomic %; if it is less than 1 atomic %, the effect of grain refinement will be insufficient, and if it exceeds 30 atomic %, the saturation magnetic flux density will be significantly lowered. Preferred M'
The content α is 2 to 15 at%. Note that M' is N
b is the most preferable in terms of magnetic properties. Furthermore, by adding M', the material has a high magnetic permeability equivalent to that of a Co-based high magnetic permeability material.

The remainder is essentially Fe, excluding impurities, but F
A part of e may be replaced by component M (Co and/or Ni). The content a of M is O≦a≦3,
Preferably, 0≦a≦0.1.

This is because when a exceeds 0.3, core loss may increase. Furthermore, by adding M, it is possible to improve corrosion resistance, improve magnetic properties, or obtain a magnetostriction adjustment effect.

When M# exceeds 10 atomic %, the saturation magnetic flux density decreases significantly. Among the alloys according to the present invention, particularly O≦a≦0.1, 0.5
When the relationship of ≦X≦2.5≦”z≦12°2≦α≦15 is satisfied, high magnetic permeability and low core loss are particularly likely to be obtained.

At least 50% or more of the structure of the Fe-based magnetic alloy according to the present invention having the above composition is composed of fine crystal grains.

It is thought that these crystal grains are mainly composed of α-Pe and B etc. are dissolved therein. These crystal grains are characterized by having an extremely small average grain size of 1000 Å or less, and are uniformly distributed in the alloy structure. The parts of the alloy structure other than the fine crystal grains are mainly amorphous. Note that even when the proportion of fine crystal grains becomes substantially 100%, the alloy of the present invention exhibits sufficiently excellent magnetic properties.

Note that it goes without saying that unavoidable impurities such as N, O, S, P, Al, and C can be considered to be the same as the alloy composition of the present invention even if they are contained to the extent that the desired properties are not deteriorated. be.

Next, a method for manufacturing the alloy of the present invention will be explained.

First, a ribbon-shaped amorphous alloy is formed from a molten metal having the above-mentioned predetermined composition by a known liquid quenching method such as a single roll method or a twin roll method. Usually, the thickness of the amorphous alloy ribbon manufactured by the single roll method etc. is 5 to 100 mm! However, those having a thickness of 25 μm or less are particularly suitable as ribbons for magnetic cores used at high frequencies.

Although this amorphous alloy may contain a crystalline phase, it is preferably amorphous in order to uniformly generate fine crystal grains during subsequent heat treatment.

Heat treatment is usually carried out by holding an amorphous alloy ribbon processed into a predetermined shape in a vacuum, in an inert gas atmosphere such as hydrogen, nitrogen, gas, etc., or in the atmosphere for a certain period of time. The heat treatment temperature and time depend on the shape and size of the magnetic core made of amorphous alloy ribbon.
Although it varies depending on the composition etc. - 450°C to 700° for boat fishing
C for about 5 minutes to 24 hours. Heat treatment temperature is 4
If the temperature is less than 50°C, crystallization will be difficult to occur (the heat treatment will take too much time. If the temperature is higher than 700"C, coarse crystal grains or non-uniform crystal grains may be produced. In addition, if the heat treatment time is less than 5 minutes, it is difficult to bring the entire processed alloy to a uniform temperature, and the magnetic properties tend to vary, making it impossible to obtain fine crystal grains uniformly. If the length is longer, not only will productivity deteriorate, but also magnetic properties will tend to deteriorate due to excessive growth of crystal grains and generation of non-uniform crystal grains.

Preferred heat treatment conditions are 500 to 650°C for 5 minutes to 6 hours, taking into account practicality, uniform temperature control, and the like.

The heat treatment atmosphere is preferably an inert gas atmosphere such as Ar+Nz, I(z, etc.) or a reducing atmosphere, but may also be an oxidizing atmosphere such as air. Cooling can be performed as appropriate by air cooling, furnace cooling, etc. It is also possible to perform multi-stage heat treatment.Furthermore, during heat treatment, the magnetic core can be heat-treated by passing an electric current through the magnetic core material or applying a high-frequency magnetic field to generate heat in the magnetic core.

The heat treatment can also be performed in a magnetic field such as direct current or alternating current. Furthermore, magnetic anisotropy can be produced in the alloy used in the present magnetic core by heat treatment in a magnetic field, thereby improving properties. It is not necessary to apply a magnetic field throughout the heat treatment, and it is often sufficient to apply the magnetic field at a temperature lower than the Curie temperature Tc of the alloy. When this magnetic core is heat-treated by applying a magnetic field to the extent that the magnetic core is saturated in the magnetic path direction, a product with good B-H curve squareness can be obtained, which can be used as a magnetic core for saturable reactors, magnetic switches, and excimer laser excitation circuits. This makes it suitable for pulse compression cores and the like. On the other hand, when heat treatment is performed by applying a magnetic field with a strength that almost saturates the magnetic core in a direction perpendicular to the magnetic path, the B-H curve becomes sloped, a product with a low squareness ratio and excellent constant permeability 6R ratio characteristics is obtained, and the operation Since the range is widened, it is suitable for transformers, nozzle filters, choke coils, etc. Furthermore, the magnetic core of the present invention can also be subjected to heat treatment in a rotating magnetic field, thereby making it possible to further increase the magnetic permeability. Also, in the case of heat treatment in a magnetic field, the heat treatment can be performed in two or more stages.

Furthermore, the magnetic properties can be improved by heat treatment while applying tension or compression force. Furthermore, the alloy of the present invention has the characteristic that it is easy to obtain a constant magnetic permeability characteristic with a low squareness ratio even when heat-treated in a non-magnetic field.

The alloy of the present invention can also be produced by forming an amorphous alloy film by a vapor phase rapid cooling method such as a sputtering method or a vapor deposition method, and then heat-treating the film to crystallize it, or by heating the substrate on which the film is to be applied. It is also possible to directly obtain the Pe-based magnetic alloy of the present invention having a fine grain structure without applying a film and performing heat treatment. A
When adding g, more preferable results can be obtained by making the film thinner.

Further, the alloy powder of the present invention in the form of powder or flakes can also be obtained by an atomization method, a cavillation method, or the like.

It is also possible to obtain a linear alloy of the present invention by spinning in a rotating liquid.

〔Example〕

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

A molten alloy consisting of 1% Cu, 1% NblO, and the balance 89% Re was rapidly cooled to a width of 5 m using a single roll method.

An alloy ribbon with a thickness of 18 μm was produced.

The obtained alloy was confirmed to have an almost amorphous single phase by X-ray diffraction, transmission electron microscopy, and boundary observation. The crystallization temperature of this amorphous alloy was 460°C.

Next, this alloy was wound to have an outer diameter of 19 mm and an inner diameter of 15 m, and was kept at 590°C for 1 hour in a nitrogen gas atmosphere, and then heated to room temperature for about 10 minutes.
Cooling was performed at a cooling rate of 0 °C/min. Next, this toroidal magnetic core was placed in a core case made of phenolic resin and its magnetic properties were measured.

Saturation magnetic flux density Bs is 12.2 kG, squareness ratio Br/Bs is 18%, coercive force Hc is 9.2 A/m・, 1 kH
The effective permeability μelk at z is 21000.100k
Core loss W at Hz 2kG! 560m for 100
It was w7cc. When the microstructure of this alloy was observed using a transmission electron microscope, it was confirmed that it consisted of an ultrafine crystal structure with a grain size of 10 nm or less. A schematic diagram of the microstructure is shown in FIG. This crystal grain is the result of electron diffractionbc
It was confirmed that it was Fe with c structure.

The alloy of the present invention has a high BS of 10 kG or more, has high magnetic permeability, low loss, and can easily obtain characteristics of a low squareness ratio, so it is suitable for common mode chokes and high frequency transformer materials. It also has low magnetostriction and is suitable for magnetic head materials.

A molten alloy consisting of Cu 1%, Nb 8%, 89% and the balance re at atomic % was rapidly cooled by a single roll method to produce an alloy ribbon having a width of 10 mm and a thickness of 12 μm.

As a result of X-ray diffraction, it was confirmed that this alloy consisted of almost an amorphous phase.

Next, a ring-shaped sample with an outer diameter of 8 mm and an inner diameter of 5 mm was taken out of this alloy, and heat treated by holding it at 550° C. for 1 hour in a vacuum. Next, the effective magnetic permeability μe+x of this alloy at 1 kHz was measured, and the sample was placed in a constant temperature bath kept at 100°C to examine changes over time.

In FIG. 2, μmB1 is the value after L time has elapsed. As a result of microstructure observation using a transmission electron microscope, it was confirmed that the microstructure was almost the same as that of Example 1.

The aging of the alloy of the present invention is significantly smaller than that of conventional Co-based amorphous alloys (Co--Pe-3i-B).

One alloy strip having a thickness of 12 μI and a width of 3 mm was produced from a molten alloy having the structure shown in Table 1 by a single roll method.

The alloy obtained as a result of X-ray diffraction was confirmed to be a predominantly amorphous alloy.

Next, make this alloy into an outer diameter of 10mm and an inner diameter of 7I! After winding around ll11 and heat-treating in Nt gas atmosphere, 100kHz,
2. The 120°C time course of core loss in kG was measured.

The results obtained are shown in Table 1. Note that the alloy obtained as a result of structure observation using a transmission electron microscope had a microstructure similar to that of Example 1.

W.

As shown in Table 1, the change in core loss over time of the alloy of the present invention is superior to that of conventional materials, and more reliable magnetic parts can be produced.

Next, a 3 μm thick alloy film having the composition shown in Table 2 was prepared on a photoceram substrate using a magnetron sputtering device.

Next, add this alloy to N! Heat treated in a gas atmosphere, IMll
The effective magnetic permeability μe4 at z was measured. Corrosion resistance was also investigated using a salt spray test.

The results obtained are shown in Table 2.

The alloy of the present invention has excellent corrosion resistance and high magnetic permeability, so it is suitable for VTR.
Suitable for magnetic heads, etc.

〔Effect of the invention〕

According to the present invention, Fe7 has excellent soft magnetic properties and low magnetostriction.
The results are remarkable since an M4n alloy can be obtained.

[Brief explanation of the drawing]

Figure 1 shows a schematic diagram of the microstructure of the alloy according to the present invention observed using a transmission electron microscope, and Figure 2 shows the effective magnetic permeability μe□ at 1 kllz of the alloy according to the present invention and a conventional amorphous alloy over time. It is a figure showing an example of change. Figure 1 Retention time (h)

Claims (1)

[Claims] 1. General formula: (Fe_1_-_aM_a)_1_0_0_-_x_-
_α_-_zA_xM'_αB_z (atomic %) (where M is Co and/or Ni, A is Cu and/or Ag, and M' is from the group consisting of Nb, Ta, Zr, Hf, Ti, and Mo At least one selected element, a, x, α and z are respectively 0≦a≦0.3, 0.1≦x≦10, 1≦α≦30, 5
≦z≦17 is satisfied. ) and at least 50% of the tissue
An Fe-based magnetic alloy comprising fine crystal grains and having an average grain size of 1000 Å or less as measured by the maximum dimension of the crystal grains. 2. General formula: (Fe_1_-_aM_a)_1_0_0_-_x_-
＿α＿−＿β＿−＿zA_xM′_αM″＿βB_z(
%) (However, M is Co and/or Ni, and A
is Cu and/or Ag, M' is Nb, Ta, Zr
, Hf, Ti and Mo, M″ is V, Cr, Mn, platinum metal element Au
, Zn, Sn, and Re, and a, x, α, β, and z are respectively 0≦a≦0.3, 0.1≦x≦10, 1 ≦α≦30, β
Satisfies ≦10, 5≦z≦17. ) and at least 50% of the tissue
An Fe-based magnetic alloy comprising fine crystal grains and having an average grain size of 1000 Å or less as measured by the maximum dimension of the crystal grains. 3. The Fe-based magnetic alloy according to claims 1 and 2, wherein the remainder of the crystal grains is amorphous. 4. The Fe-based magnetic alloy according to claims 1 and 2, wherein the structure is substantially composed of fine crystal grains. 5. The average grain size measured at the maximum dimension of the crystal grains is 50
The Fe-based magnetic alloy according to any one of claims 1 to 4, wherein the Fe-based magnetic alloy has a thickness of 0 Å or less.