JPH0768604B2 - Fe-based magnetic alloy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a Fe-based magnetic alloy suitable for use in a high frequency band,
In particular, the present invention relates to a Fe-based magnetic alloy suitable for a dust core or a magnetic shield material, which is easy to be powdered and whose structure has most of ultrafine crystal grains.

[Conventional technology]

Conventionally, Fe, permalloy, silicon steel and the like have been used as magnetic core materials such as dust cores and magnetic shield materials.

Recently, Fe-based and Co-based amorphous alloys have also been studied, and a powder magnetic core formed by compression molding of these powders, a shielding material formed into a sheet by mixing with a resin, and the like have been studied.

Regarding these alloy powders, for example, Japanese Examined Patent Publication No. 54-50463,
It is described in JP-B-55-128507.

[Problems to be solved by the invention]

 However, these alloys have various problems.

In the case of permalloy alloy, 80 wt% Ni with good magnetic properties
In the case of alloys having similar compositions, there is a defect that the saturation magnetic density is as low as 7.5 kG, and in the case of silicon steel, there is a defect that the soft magnetic properties are inferior.

In the case of Fe-based amorphous alloy, the saturation magnetic flux density is high, but there is a drawback that the magnetostriction is large and the magnetic characteristics are largely deteriorated by the influence of the distortion. On the other hand, a Co-based amorphous alloy has a small magnetostriction and is hardly affected by the strain, but the saturation magnetic flux density is usually 10 kG or less, which is not sufficient like the permalloy alloy. Further, there is a drawback that the change over time is large.

Recently, we have added Cu and Nb, Mo, Ta, W, etc. in combination.
Fe-based alloy has an ultra-fine grain structure, excellent soft magnetism,
It has been found that it exhibits low magnetostriction characteristics.

However, in the case where the powder is used after being powdered, a composition that is easily embrittled is more preferable because powdering is easier.

An object of the present invention is to provide an Fe-based magnetic alloy having excellent soft magnetic properties, small magnetostriction, and easily powdered.

[Means for solving problems]

A first invention of the present invention is that Cu is 3 to 10 atom%, B is 25 atom% or less, and at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo is used. Contains 0.1 to 30 atom%, balance F
Fe-based magnetism characterized by having a composition consisting of e and unavoidable impurities, at least 50% of the structure consisting of fine crystal grains, and having an average grain size of 1000 Å or less measured by the maximum dimension of the crystal grains. It is an alloy.

The second invention is at least 3 to 10 atomic% of Cu, 25 atomic% or less of B, 30 atomic% or less of Si, and at least one selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo. It has a composition containing 0.1 to 30 atomic% of one element, the balance being Fe and unavoidable impurities, and at least 50% of the structure is composed of fine crystal grains. It is an Fe-based magnetic alloy characterized by having an average of 1000Å or less.

A third aspect of the invention is at least Cu selected from the group consisting of 3 to 10 at%, B at 25 at% or less, Si at 30 at% or less, and Nb, W, Ta, Zr, Hf, Ti and Mo. 0.1 to 30 atomic% of one element, the balance Fe and Fe less than 50 atomic% Co and / or
Characterized by having a composition consisting of inevitable impurities substituted by Ni, at least 50% of the structure consisting of fine crystal grains, and having an average grain size of 1000 Å or less measured by the maximum dimension of the crystal grains. It is a Fe-based magnetic alloy.

The fourth invention is at least Cu selected from the group consisting of 3 to 10 at%, B at 25 at% or less, Si at 30 at% or less, and Nb, W, Ta, Zr, Hf, Ti and Mo. 0.1 to 30 atomic% of one element, V, Cr, Mn, Al, white metal element, Sc, Y, rare earth element, Au, Zn, S
10 at least one element selected from the group consisting of n and Re
Containing less than or equal to atomic%, the balance has a composition consisting of Fe and unavoidable impurities, at least 50% of the structure consists of fine crystal grains, and the average grain size measured by the maximum dimension of the crystal grains is 1000.
Fe-based magnetic alloy characterized by being Å or less.

Further, the fifth invention is such that Cu is 3 to 10 atom% and B is 25 atom%.
Hereinafter, Si is 30 atomic% or less, 0.1 to 30 atomic% of at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo, C, Ge, P, Ca, Sb. , In, Be, As containing at least one element selected from the group consisting of 20 atomic% or less and the balance being Fe and inevitable impurities, and at least the texture
The Fe-based magnetic alloy is characterized in that 50% consists of fine crystal grains, and the average grain size measured by the maximum dimension of the crystal grains is 1000 Å or less.

In the present invention, at least the tissue having the above composition is
Alloys that consist of 50% of fine crystal grains and have an average grain size of 1000Å or less measured by the maximum dimension of the crystal grains exhibit excellent soft magnetic properties and are easy to be powdered. The present invention has been accomplished by finding that it is a suitable alloy for the above.

In the present invention, Cu is an essential element, and when contained in an appropriate amount, it has the effect of making the alloy easily brittle and making it powdery. It also has the effect of improving corrosion resistance. Its content is in the range of 3 to 10 atomic%. If it is less than 3 atom%, it is difficult to pulverize, and if it exceeds 10 atom%, the saturation magnetic flux density is remarkably lowered, which is not preferable.

The alloy according to the present invention is usually manufactured as follows.

First, an amorphous alloy having the above composition is rapidly cooled from molten metal, or is manufactured by a vapor phase quenching method such as a sputtering method or a vapor deposition method, which is further heated to form at least 50% or more of the microstructure of a fine bcc Fe solid solution crystal. It is manufactured by the step of forming into grains.

Cu has an effect of improving soft magnetism, but becomes slightly harder in a composition of 3 atomic% or more. Although the reason for improving this soft magnetism is not clear, it is considered as follows.

The interaction parameter between Cu and Fe is positive, the solid solubility is low and there is a tendency to separate, and when an amorphous alloy of the above composition is heated, a large number of Fe-rich regions are formed, and crystallization occurs with these as nuclei. As it progresses, Cu is extruded around.

This crystal nucleation effect by Cu is one of the reasons why the structure is made finer, and the other major reason is that Nb, Ta,
The crystal grain growth suppressing effect by Mo, W, etc. can be mentioned. The addition of Nb, Ta, Mo, W, etc. and the combined effect of Cu make the crystal grains extremely fine and provide excellent soft magnetism.

By the way, the Cu content of the alloy of the present invention is 3 atomic% or more, and Cu is easily separated in the manufacturing method by the liquid quenching method, and Cu is separated before the heat treatment or near the grain boundary when crystallized by heat treatment. Cu concentration becomes extremely high. Therefore, the soft magnetic characteristics
Although it deteriorates to some extent as compared with an alloy having a Cu content of less than 3 atomic%, it can be sufficiently used as a soft magnetic material, is easily embrittled, and is easily powdered. Therefore, the alloy is suitable as a dust core or a shield material using powder.

At least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo has the effect of refining crystal grains and improving soft magnetism as described above. The content is 0.1 to 30 atomic%, and a more desirable range is 1 to 10 atomic%.
In this range, particularly excellent soft magnetism can be obtained. If these elements are not contained, the crystal grains become large and the soft magnetic characteristics are significantly deteriorated, which is not preferable.

Si and B are elements useful for refining the alloy and adjusting the magnetostriction. The alloy of the present invention is preferably obtained by once forming an amorphous alloy by the effect of adding Si and B and then forming fine crystal grains by heat treatment.

The reason for limiting the Si content is that if it exceeds 30 atomic%, the magnetostriction becomes large under the condition of good soft magnetic characteristics, which is not preferable, and more preferably 10 to 25 atomic%. In this range, particularly good soft magnetic characteristics can be obtained.

The reason for limiting the B content is that if it exceeds 25 atomic%, the magnetostriction becomes large under the condition of good soft magnetism, which is not preferable, and the particularly preferable composition range is 3 to 12 atomic%. Within this range, an alloy having particularly good soft magnetism and small magnetostriction can be obtained.

It is at least one element selected from the group consisting of C, Ge, P, Ga, Sb, In, Be and As, and its magnetostriction is adjusted and its content is in the range of 20 atomic% or less. The reason for this is that if it exceeds 20 atom%, the saturation magnetic flux density will drop significantly,
More preferably, it is 10 atomic% or less. In this range, relatively good soft magnetism is easily obtained.

It is at least one element selected from the group consisting of V, Cr, Mn, Al, white metal elements, Sc, Y, rare earth elements, Au, Zn, Sn and Re, and has the effects of improving corrosion resistance and adjusting magnetostriction. And its content is 10 atomic% or less. The reason for this limitation is that the saturation magnetic flux density is significantly reduced when the content exceeds 10 atomic%.

The alloys of the present invention are Li, Mg, Ca, Sr, Ba, Ag, Cd, Pb, Bi, N, O, S, S
The content of e, Te, etc. may be 2 atomic% or less, but if it exceeds 2 atomic%, soft magnetism is significantly deteriorated, which is not preferable.

The balance is mainly Fe, except for impurities.
Parts may be replaced by the components M (Co and / or Ni). The content of M is less than 50 atomic% of Fe, preferably less than 30 atomic%, and more preferably less than 10 atomic%. In this range, more preferable soft magnetism can be obtained.

The alloy of the present invention is mainly composed of a Fe solid solution having a bcc structure, but it is a compound Fe of an amorphous phase or a transition metal such as Fe ₂ B, Fe ₃ B or Nb.
_It may also contain ₃ Si ordered phase. These phases may deteriorate the magnetic properties, and it is particularly desirable that the compound phases such as Fe ₂ B have a great influence and are not present as much as possible.

The alloys of the present invention are mainly composed of ultrafine and uniformly distributed crystal grains having a grain size of 1000 Å or less, but alloys exhibiting more excellent soft magnetism often have an average grain size of 500 Å or less. Particularly preferred soft magnetic properties are when the particle size is 20 to 200Å average.

The part of the alloy structure other than the fine crystal grains is mainly amorphous or Cu, but the alloy of the present invention exhibits sufficiently excellent soft magnetism even when the crystal phase becomes substantially 100%.

The alloy of the present invention is produced by a method such as a single roll method, a twin roll method, a centrifugal quenching method, etc., after which an amorphous ribbon is produced and then heat-treated to form fine crystal grains, a vapor deposition method, a sputtering method or an ion plating method. The crystalline film can be prepared by various methods such as a method of heat-treating and crystallization after preparation, a method of spinning in a rotating liquid or a glass coating spinning method, and a method of obtaining an amorphous wire and then heat-treating and crystallizing.

The heat treatment performed to obtain the alloy of the present invention is carried out for the purpose of reducing internal strain, improving the soft magnetism with a fine grain structure, and reducing magnetostriction to facilitate pulverization.

The heat treatment is usually performed in vacuum or in an atmosphere of an inert gas such as hydrogen gas, nitrogen gas or argon gas. However, in some cases, it may be performed in an oxidizing atmosphere such as in the air.

The heat treatment temperature and time vary depending on the shape, size, and composition of the amorphous alloy, but generally higher than the crystallization temperature 450 ℃ ~ 700
5 minutes to 24 hours at ℃ is desirable.

The conditions of temperature rising and quenching during the heat treatment can be arbitrarily changed depending on the situation. Further, the heat treatment may be performed at the same temperature or different temperatures in a plurality of times, or the heat treatment may be performed in a multi-step heat treatment pattern. Further, the present alloy can be heat-treated in a DC or AC magnetic field. Magnetic anisotropy can be generated in the present alloy by heat treatment in a magnetic field.

It is not necessary to apply a magnetic field during the heat treatment, and a sufficient effect can be obtained even when applied at a temperature lower than the Curie temperature Tc of the alloy according to the present invention. The Curie temperature of the main phase formed by heat treatment of the alloy according to the present invention is higher than that of the amorphous case, and the heat treatment in the magnetic field can be applied even at a temperature higher than the Curie temperature of the amorphous alloy. Further, the heat treatment in the rotating magnetic field may be performed as part of the heat treatment process. The alloy can also be heat-treated by applying an electric current to the alloy during the heat treatment or applying a high-frequency magnetic field to heat the alloy. In the case of heat treatment in a magnetic field, heat treatment can be performed in two or more steps. Further, it is possible to adjust the magnetic characteristics by applying heat treatment while applying compressive force.

As described above, the alloy of the present invention is easily embrittled after the heat treatment, and the ribbon can be easily pulverized by mechanical grinding. Further, an already powdered alloy such as atomized powder can be easily pulverized.

In the case of producing a dust core, it can be used by forming an insulating layer on the surface of the powdered alloy of the present invention, or by plating the surface when using it as a shield material or the like.

〔Example〕

The present invention will be described in detail with reference to the following examples, but the present invention is not limited thereto.

Example 1 Cu 5%, Si 16.5%, B 6%, Nb 3% and the balance substantially F in atomic%
A ribbon having a width of 5 mm and a thickness of 18 μm was produced from a molten metal having a composition of e by a single roll method.

As a result of X-ray diffraction and structure observation, it was confirmed that this alloy ribbon was mainly composed of an amorphous phase. Next, wind this alloy in a toroidal shape with an outer diameter of 19 mm and an inner diameter of 15 mm in N ₂ gas atmosphere.
After holding at 550 ° C. for 1 hour, it was cooled to room temperature and magnetic properties were measured.

Saturation magnetic flux density Bs is 1.1kG, 100kHz, 2kG core loss
It was 530 mW / cc, the effective magnetic permeability at 1 kHz was 5500, the coercive force Hc was 0.120e, and the saturation magnetostriction λs was + 0.5 × 10 ^-6 . As a result of microscopic observation, it was confirmed that this alloy was composed of ultrafine crystal grains with a grain size of 1000 Å or less.

The alloy ribbon after this heat treatment was extremely brittle, and when pulverized with a vibration mill, it could be easily pulverized compared to an alloy with a Cu addition amount of 1 atom%, and the pulverization time was shortened by about 20%.

Next, 7 wt% of a heat-resistant inorganic varnish was added to this alloy powder as a binder, the temperature was raised to 500 ° C., and a powder magnetic core was produced while applying pressure.

The effective magnetic permeability was 160 and the frequency characteristics were good.

Example 2 The width of the molten alloy having the composition shown in Table 1 was 10 by the single roll method.
A ribbon having a thickness of 15 mm and a plate thickness of 15 μm was produced. As a result of observing the structure by X-ray diffraction and a transmission electron microscope, it was confirmed that most of the crystalline phase was an amorphous phase although some of the crystalline phase was observed.

Next, this alloy ribbon was wound into a toroidal shape in the same manner as in Example 1 and heat-treated at a temperature equal to or higher than the crystallization temperature. The structure of the alloy after heat treatment was similar to that of Example 1, and it was confirmed that the alloy had a fine crystal grain structure. Next, the magnetic characteristics of the magnetic core after the heat treatment were measured. The results obtained are shown in Table 1. In addition, the Fe-based amorphous alloy is crushed with a vibration mill, and the crushing time when the powder of 48mesh under is 50% and the powder of 48mesh under is 50%.
The ratio tc / to with the crushing time of the alloy of the present invention, which is%, is also shown.

As can be seen from the table, the alloy of the present invention has high permeability and low loss.
It exhibits excellent soft magnetic properties equivalent to or better than Fe-based amorphous alloys.

Also, the crushing time when the powder of 48mesh under becomes 50% or more
Shorter than Fe-based amorphous and Cu-free materials, and easy to pulverize.

Therefore, it is suitable for various magnetic core materials such as dust cores and shield materials.

Example 3 A ribbon having a thickness of 25 μm and a width of 3 mm was produced from the molten alloy having the composition shown in Table 2 by the twin roll method. Then, after heat treatment in the same manner as in Example 2, the powder was crushed with a vibration mill to obtain 48 mesh under powder.
The grinding time to reach 50% was determined. Table 2 shows Fe _74.5 Cu ₁ Nb ₂ Si.
The ratio tc / to of the crushing time when the powder of 48 mesh under is 50% in the case of _13.5 B ₉ alloy and the crushing time in the case of the present invention is shown.

[Effects of the Invention] According to the present invention, it is possible to obtain an alloy having an ultrafine crystal grain structure, which can be easily pulverized and has excellent soft magnetic properties, and therefore the effects are remarkable.

Claims (5)

[Claims] 1. A Cu content of 3 to 10 atom%, a B content of 25 atom% or less, and an N content.
At least one element selected from the group consisting of b, W, Ta, Zr, Hf, Ti and Mo is contained in an amount of 0.1 to 30 atomic%, and the balance has a composition consisting of Fe and unavoidable impurities and has at least 50 %
Fe is characterized in that it is composed of fine crystal grains, and the average grain size measured by the maximum dimension of the crystal grains is 1000 Å or less.
Base magnetic alloy. 2. Cu of 3 to 10 atomic%, B of 25 atomic% or less, Si
Is contained in an amount of 30 atomic% or less, 0.1 to 30 atomic% of at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo, and the balance being Fe and inevitable impurities. The Fe-based magnetic alloy is characterized in that at least 50% of the structure is composed of fine crystal grains, and the average grain size measured by the maximum dimension of the crystal grains is 1000 Å or less. 3. Cu of 3 to 10 atomic%, B of 25 atomic% or less, Si
Of 30 at% or less, 0.1 to 30 at% of at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo, and the balance Fe and less than 50 at% of Fe. Substitute with Co and / or Ni and have a composition of unavoidable impurities, at least 50% of the structure consists of fine crystal grains, and the average grain size measured by the maximum dimension of the crystal grains is 1000Å or less. Fe-based magnetic alloy characterized by. 4. Cu of 3 to 10 atomic%, B of 25 atomic% or less, Si
Is 30 atomic% or less, 0.1 to 30 atomic% of at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo, V, C
Contains at least one element selected from the group consisting of r, Mn, Al, white metal elements, Sc, Y, rare earth elements, Au, Zn, Sn, Re in an amount of 10 atom% or less, and the balance Fe and inevitable impurities. Fe-based magnetic alloy having the following composition, wherein at least 50% of the structure is composed of fine crystal grains, and the average grain size measured by the maximum dimension of the crystal grains is 1000Å or less. 5. A Cu content of 3 to 10 atomic%, a B content of 25 atomic% or less, and a Si content.
Is 30 atomic% or less, 0.1 to 30 atomic% of at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo, C, G
At least one element selected from the group consisting of e, P, Ca, Sb, In, Be, As is contained at 20 atomic% or less, and the balance is composed of Fe and inevitable impurities, and at least 50% of the structure. Is composed of fine crystal grains, and the average grain size measured by the maximum dimension of the crystal grains is 1000 Å or less, Fe-based magnetic alloy.