JPH02240243A - Fe-base superfine-crystal alloy with low loss - Google Patents

Abstract

PURPOSE:To obtain an Fe-base superfine-crystal alloy with low loss by providing a specific composition by adding Hf, V, Nb, Ta, Cr, Mo, W, etc., and Au to an Fe-Si-B amorphous alloy. CONSTITUTION:The above alloy is an Fe-base superfine-crystal alloy with low loss having a composition represented by a general formula Fe100-a-x-y-zMaAuxSiyBz (where M means one or more elements among Hf, V, Nb, Ta, Cr, Mo, and W, the symbols (a), (x), (y), and (z) stand for 0.5-3, 0.5-3, 5-19, and 5-25, respectively, and 15<=y+z<=30), and this alloy has a fine and uniform crystalline structure containing the above alloying elements to supersaturation and consisting of alpha-Fe. The above Fe-base superfine-crystal alloy can be obtained by preparing an alloy with the prescribed composition by liquisol quenching, such as chill block melt spinning, and then carrying out annealing under the conditions appropriate for the crystallization of amorphous phase into alpha-Fe. The above alloy is reduced in loss under high-frequency waves and excellent in magnetic permeability and is suitable for use in high-frequency transformer, etc.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is directed to ultrafine crystal m that is suitable as a magnetic core material for various choke coils, high frequency transformers, supersaturation reactors, and other electronic components used at high frequencies of 20 kHz or higher. This relates to a Fe-based magnetomagnetic alloy consisting of a woven fabric.

(Prior Art) Conventionally, ferrite has been mainly used as a magnetic core material for high frequency transformers, choke coils, etc. because it has advantages such as high resistance and low eddy current loss.

However, since ferrite has a low saturation magnetic flux density and a low Curie temperature, it has the disadvantage that as the operating magnetic flux increases, the magnetic core becomes larger.

On the other hand, permalloy is a magnetic core with a higher saturation magnetic flux density and Curie temperature than ferrite, but because permalloy has low electrical resistance, it has the disadvantage of high iron loss in the high frequency range.

In recent years, amorphous alloys have been viewed as promising as excellent magnetic core materials because of their high saturation magnetic flux density, which has the potential to compete with conventional magnetic core materials.

However, Pe-based amorphous alloys (e.g. Fe-5
i-B) has a problem in that -m has a large iron loss at high frequencies. On the other hand, Co-based amorphous alloys with zero magnetostriction (e.g. C
o-Re-5t-B) has higher magnetic permeability and lower iron loss than Fe-based amorphous alloys, so it has excellent high-frequency characteristics, but generally the magnetic permeability and iron loss change over time, which poses a practical problem. be.

Therefore, in order to reduce the loss of Fe-based amorphous alloys, a method of precipitating fine α-Fe crystal grains through heat treatment in the amorphous alloy to refine the magnetic domains and reduce the loss (Unexamined Japanese Patent Publication No. (Refer to Japanese Patent Application Laid-Open No. 1983-52554), A method of obtaining the same effect by finely dispersing undissolved Cu in an amorphous alloy (Refer to Japanese Unexamined Patent Publication No. 60-52557), M
Attempts have been made to reduce magnetostriction and loss by adding o or Nb.

(Problem to be solved by the invention) However, it still does not necessarily have sufficient characteristics, and C
There was a problem in that iron loss was significantly larger than that of o-based amorphous alloys.

In this way, although Fe-based amorphous alloys have the advantage of less change over time compared to Co-based amorphous alloys,
Since the iron loss at high frequencies is larger than that of a Co-based amorphous alloy, the temperature rise in the magnetic core increases as the frequency increases due to the increase in iron loss.

(Means for Solving the Problems) The present invention solves the problems of the prior art and provides magnetic cores for various choke coils, high frequency transformers, supersaturation reactors, etc. used for high frequency applications, particularly at frequencies of 59k)lz or higher. Fe, which has an ultrafine crystal structure, is a suitable material.
This was made for the purpose of providing a magneto-magnetic alloy based on Fe-3i-B based amorphous alloy with M element (If
C by adding f, V, NblTa, CrtMo2Ga) and Au and heat treating this alloy.
Fe has low loss characteristics comparable to o-based amorphous alloys.
It is characterized by having a base ultra-ultra fine crystal alloy.

That is, the alloy of the present invention is represented by the following compositional formula, and is characterized by having a uniform 4-fine crystal structure consisting of α-Fe containing supersaturated alloying elements.

Fe+00-a-x-y-m M^u, si, B.

Here, M is Hf, L Nb, Ta+ Cr, M
One or more of o+-, and 0.5≦
a≦3゜0.5≦X≦3.5≦y≦19.5≦2≦25
．． 15≦y+2≦30.

Fe-based amorphous alloys have a larger magnetostriction than Co-based amorphous alloys, so they have a large saturation magnetic flux density that does not change over time, but iron loss at high frequencies is lower than that of Co-based non-crystalline alloys. Inferior to crystalline alloys.

On the other hand, silicon steel made of α-Pe containing Si has smaller magnetostriction than Fe-based amorphous alloys, but because it has magnetocrystalline anisotropy, iron loss at high frequencies is lower than that of Fe-based amorphous alloys. Inferior to alloys. Furthermore, in the field of crystalline magnetic thin films, it is known that soft magnetic properties are significantly improved by forming the film under conditions that allow a fine crystal structure to be obtained.

Therefore, Au particles are dissolved in the matrix by adding about 1 atomic % of Au to Fe-5i-B alloy and performing liquid quenching, and then this amorphous alloy is heat-treated to form α-Fe crystals. When forming a structure, Hf and Vt have the effect of stabilizing this α-Fe and suppressing its crystal grain growth.
By adding one or more of NblTa and CrtMo+-, the resulting alloy as a whole becomes a microcrystalline structure consisting of α-Fe, resulting in a soft, low-loss alloy comparable to Co-based amorphous alloys. It was discovered that a magnetic alloy can be obtained. This is considered to be because the apparent main magnetocrystalline anisotropy is offset by the fine crystal structure, and the magnetostriction is reduced because α-Fe contains St.

Here, Au is an essential element for the refinement of α-Pe crystals produced by heat treatment, and its content is reduced to 0.
The reason for limiting it to 5-3 atomic % is that if it is smaller than 0.5 atomic %, there is no effect of adding Au, whereas if it is larger than 3 atomic %, Au addition will not be effective.
This is because uniform dispersion of u becomes difficult and a fine crystal structure cannot be obtained, making it impossible to obtain the desired soft magnetic properties.

Further, the content of the additive component M that replaces a part of Fe was set to 0.
The reason for limiting it to 5-3 atomic % is that if it is smaller than 0.5 atomic %, there will be no effect of suppressing α-Fe crystal grain growth by adding M, and if it is larger than 3 atomic %, the saturation magnetic flux density will decrease significantly. It is to invite.

Further, the reason for limiting y and 2 in the present invention is mainly that y is 5 to 19 atom%, 2 is 5 to 25 atom%, and y
This is because if +z is outside the range of 15 to 30 at%, embrittlement will be severe after liquid quenching, making it difficult to produce a non-quality alloy.

The alloy of the present invention is produced by producing an alloy having the above-mentioned composition by a single roll method, a twin roll method, or other known liquid quenching method, and then
It can be manufactured by annealing at an appropriate temperature and time so that the amorphous phase crystallizes into α-Fe.

(Example) Table 1 shows the iron loss of the Fe-3i-B ultrafine crystal alloy according to the present invention, conventional magnetic core materials such as Fe-based amorphous alloy, Co-based amorphous alloy, and Mn-Zn ferrite. This is a table comparing. In this example, a rapidly solidified alloy ribbon having a width of 5 mm and a thickness of about 20 μm was produced by a single roll method. When this structure was examined by X-ray diffraction, it was found to be amorphous. This ribbon was wound into a coil with an inner diameter of 15 m.
A wound magnetic core with an outer diameter of 19 cranes was used, and after annealing for 60 minutes in a nitrogen gas atmosphere at a temperature appropriately selected according to the alloy composition, the peak value Bm of the magnetic flux density was set to 2k using a U function needle.
G, iron loss at frequency f up to 100kHz -z/1
00k was measured.

When the structure of the ribbon after annealing was examined by X-ray diffraction, only the α-Fe peak was observed in all of the examples. Furthermore, when the crystalline Mn texture of the alloy of the present invention was observed using a transmission electron microscope, it was found that in all Examples, as shown in Table 1, it was an ultrafine crystal of 50 nm or less.

As can be seen from Table 1, the iron loss of the alloy of the present invention is smaller than that of conventional Fe-based amorphous alloys, ferrites, and the like.

In this example, the alloy was produced by the single roll method, but the alloy of the present invention is not limited to the single roll method, and the alloy of the present invention can also be produced by other known liquid quenching methods.

(Effects of the Invention) As described above, the Fe-based fine crystal alloy of the present invention has lower loss at high frequencies than conventional Fe-based amorphous alloys, and has excellent magnetic permeability. When used in reactors, etc., excellent characteristics can be obtained.

Applicant's agent Jun Kawauchi

Claims (1)

[Claims] The composition has the general formula Fe_1_0_0_-_a_-_x_-_y_-_zM
Au_xSi_yB_z [Here, M is Hf, V, Nb
, Ta, Cr, Mo, and W, and 0.5≦a≦3, 0.5≦x≦3, 5≦y≦1
9, 5≦z≦25, 15≦y+z≦30] A low-loss Fe-based ultrafine crystal alloy.