JPS6070157A - Amorphous alloy and its manufacture - Google Patents

Abstract

PURPOSE:To obtain an amorphous alloy having high magnetic permeability in the range of audible frequency to MHz high frequency and small coercive force and undergoing hardly a change with the lapse of time by regulating the Curie temp. of an amorphous Co base alloy to <=230 deg.C and magnetostriction to approximately zero. CONSTITUTION:Starting materials for an alloy represented by the formula are melted, and the melt is rapidly cooled to manufacture an amorphous Co base alloy. In the formula, M is one or more among Fe, Ti, V, Cr, Mn, Ni, Y, Zr, Nb, Mo, Hf, Ta, W, Ru, Rh, Pd, Os, Ir, Pt and a rare earth element, N is one or more among Si, B, P, C, Ge and Al, 0.03<=a<=0.3, and 65<=z<=82. The amorphous Co alloy is heat treated at a temp. between the Curie temp. of the alloy and a temp. below the crystallization temp. to regulate the Curie temp. to <=230 deg.C and the magnetostriction to approximately zero.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a cobalt-based amorphous material having high magnetic permeability (μ), small change in permeability over time, and low coercive force in a high frequency range. Concerning alloys and their manufacturing methods.

[Technical background of the invention and its problems]

In recent years, the development of devices that apply electromagnetism has been remarkable. As one example, switching power supplies incorporating magnetic amplifiers are widely used as stabilized power supplies for computer peripherals and general communication equipment.

The main part constituting this magnetic amplifier is a saturable reactor, and its magnetic core requires a magnetic core material with excellent square magnetization characteristics. Conventionally, such magnetic core materials include Fe-
Ni alloys, such as Sendelta (trade name), are often used.

Although this center delta has excellent square magnetization characteristics,
In a high frequency range of approximately 20 KHz or higher, the coercive force increases, iron loss increases, heat is generated, and the device becomes unusable.

Therefore, the switching frequency of a switching power supply incorporating a magnetic amplifier has been generally limited to 20 KHz or less.

However, recently, the switching frequency has been increased to meet the demand for smaller and lighter switching power supplies. On the other hand, as mentioned above, center delta is not sufficient, and so far, other satisfactory magnetic core materials have low coercive force in the high frequency range, and have excellent square magnetization characteristics and thermal stability. has not been discovered yet.

In addition, recently there has been a strong demand for magnetic cores for audio step-up transformers with improved magnetic properties. In particular, there is a demand for a material that can stably obtain high magnetic permeability, but a satisfactory material has not yet been found.

In response to such demands, efforts have recently been made to apply amorphous magnetic alloys. For example, attempts have been made to use a cobalt-based amorphous alloy as the magnetic core of an audio step-up transformer, but even in this case, even under a relatively strong measurement magnetic field of 10 moe, its IKHz magnetic permeability (μ + lc )
The magnetic permeability is only about 12×104, and even higher magnetic permeability is required in order to obtain better electromagnetic conversion characteristics.

In addition, cobalt-based amorphous magnetic alloys that have been tried in the past have had the problem of large changes in magnetic permeability over time, resulting in deterioration of electromagnetic conversion characteristics over time.

Such amorphous magnetic alloys are usually produced by melting an alloy material with a predetermined composition ratio and rapidly cooling it (approximately 108°C/second or more).
(liquid quenching method).

However, at this time, since strain is accumulated in the obtained amorphous magnetic alloy, excellent soft magnetic properties cannot be obtained as it is.

Therefore, various heat treatments have been tried in the past.

For example, the obtained amorphous magnetic alloy is once cured at a temperature (T
(There is a method to obtain an amorphous alloy with high magnetic permeability and low coercive force by heat treatment at an appropriate temperature higher than the crystallization temperature and lower than the crystallization temperature, but this method is still satisfactory. In this case, the cooling medium used for quenching is usually one at room temperature such as water, and media with a boiling point below 0°C, such as liquid nitrogen, would rather cause bumping and impair the quenching effect. It was considered an object and was not used.

As mentioned above, to date, no amorphous magnetic alloy has been developed that has high magnetic permeability, little change over time, high stability, and low coercive force in a high frequency range.

[Purpose of the invention]

The present invention uses a cobalt-based material that has high magnetic permeability, small change over time, and low coercive force in the high frequency range from the audio frequency range to the MH2 range, and is useful as a magnetic core material for electromagnetic devices used within this frequency range. The purpose is to provide an amorphous alloy and its manufacturing method.

[Summary of the invention]

・K inventors have developed T of cobalt-based amorphous alloys of various compositions.
In the process of investigating the correlation between c and magnetic permeability, we found that Tc was 23
Contrary to conventional expectations, if a cobalt-based amorphous alloy with almost zero magnetostriction at 0°C or below is heat treated at a temperature above Tc but below the crystallization temperature and then quenched in liquid nitrogen instead of in water, The present invention was completed based on the discovery that the obtained amorphous alloy has high magnetic permeability and low coercive force, and the change in magnetic permeability over time is small. It is thought that the magnetostriction of cobalt-based amorphous alloys hardly changes due to heat treatment.

That is, the high magnetic permeability cobalt-based amorphous alloy of the present invention is
It is characterized by a Tc of 230°C or less and a magnetostriction of approximately zero, and its manufacturing method involves heat treating a cobalt-based amorphous alloy at a temperature higher than or equal to the Tc of the alloy and lower than its crystallization temperature, and then heating the shell alloy to a boiling point. It is characterized by rapid cooling in a cooling medium of 0°C or lower.

The high magnetic permeability cobalt-based amorphous alloy of the present invention is a cobalt-based amorphous alloy manufactured by the liquid quenching method described above and having the composition described below.

It should be noted that "substantially zero magnetostriction" refers to a range within ±5 x 10-6. Preferably, the range is within ±I x 10''-6 in order to obtain good magnetic properties.

Moreover, if Tc is up to 230° C., more stable magnetic properties can be obtained. Its composition has the general formula: (
Cot-aMa)zN,oo-2 (wherein M is Fe,
Ti, Vt Cr, Mn, Ni + Yr Z
r+Nb, MO, Hf, Ta, w, Ru, R
h1Pdk: QB+Ir, pt, represents at least one element selected from the group of rare earth elements; N is SL;
Represents at least one element selected from the group of B, P, C, Ge, and Al; a and Z are each 0.03
≦a≦0.30. 65≦Z≦82).

Among each component, M is a component that contributes to magnetostriction adjustment and thermal stability. Among these, for magnetostriction adjustment, Fe, Mn,
Ni is effective, and in terms of thermal stability, V, Cr,
Ni, Nb, Mo, Ta, and W are particularly effective components.

Further, N is an element necessary to make the alloy amorphous, and B, 81 is preferable in terms of the thermal stability of the obtained alloy.

a and 2 are Tc, one of the factors that determines the amorphous state, and 2 can obtain a preferable amorphous state between 65 and 82, and in relation to this, a is 0.03 or more. A material with a magnetostriction of approximately 4 and improved thermal stability is obtained, and this effect continues up to a of 0.30, and in this range, a combination in which the magnetostriction is approximately zep and Te shows a preferable value. a
, z are 0.04≦a≦0.16, respectively. 68≦2≦
A number that satisfies the relationship of 77 is preferred because it is easy to obtain desired characteristics and is practical.

The starting material of the present invention can be easily produced by blending a predetermined amount of each of the above-mentioned elements to form a master alloy, and applying a liquid quenching method to the master alloy. The resulting material is usually in the form of a plate-like ribbon. In this case, it is substantially difficult to produce a ribbon with a thickness of less than 8 μm using the liquid quenching method. Moreover, when the thickness exceeds 30 μm, the coercive force in the high frequency range increases, but the magnetic permeability in the audio frequency range is improved. Therefore, the thickness of the ribbon is appropriately selected depending on the type of electromagnetic device to which it is applied. Usually, it is preferably about 8 to 60 μm.

Next, this ribbon (amorphous alloy) is heat-treated at a temperature higher than or equal to the Te of the alloy and lower than the crystallization temperature. The heat treatment temperature is Tc
In the case of non-droplets, it is difficult to obtain high magnetic permeability and low coercive force due to the occurrence of induced magnetic anisotropy, and if the temperature is higher than the crystallization temperature, the alloy crystallizes and the purpose cannot be achieved. The heat treatment may be performed in the air or atmosphere. The processing time is not particularly limited.

Thereafter, the ribbon is put into a cooling medium having a boiling point of 0° C. or lower to rapidly cool it. This is one of the points of the present invention. Examples of the cooling medium include liquid nitrogen, liquid oxygen, liquid air, and liquid helium, but liquid air and liquid nitrogen are preferred because they are inexpensive and easily available.

[Embodiments of the invention]

Example 1 The composition is (Coo, gl Feo, os Nbo, o+)
A ribbon of amorphous alloy of yg 5i14 B10 was produced by a single roll process. Thin strip width 10vrw, thickness 42~45μ
m, and Tc was 180°C. This ribbon was wound to form a core having an outer diameter of 18 degrees and an inner diameter of 12 degrees, which was heat-treated at 380° C. and then placed in liquid nitrogen.

The obtained core was wound with a wire, and the I KHz magnetic permeability (μlk) in an external magnetic field of 2 mQa was measured with an LCR meter, and it was found to be 200,000 o 10 mOe.
In the measured magnetic field, μmk was 300,000.

The change in magnetic permeability of this core at room temperature over time was investigated, and the results are shown in Fig. 1 with (•) marks. For comparison, the change in magnetic permeability of a core manufactured in the same manner as in Example 1 except that quenching in water at 10° C. was performed instead of quenching with liquid nitrogen is shown as a symbol. Note that in FIG. 1, the vertical axis is normalized to the initial value.

Examples 2 and 3 Amorphous alloy ribbons with different Tc were produced in the same manner as in Example 1 by changing the composition ratios of Co, Fe, Nb, Si, and B. The thickness of the ribbon is 42-45μ
It was m.

Cores having an outer diameter of 18 mm and an inner diameter of 12 diameters were wound and formed from these ribbons, heat treated at their respective optimum temperatures, and quenched with liquid nitrogen. Then, as in Example 1, μmk was measured for each core using a measurement magnetic field of 2 m0e. The results are shown in FIG. 2 as a relationship diagram with the Tc of each core, marked with (.).

For comparison, the μm of each core when rapidly cooled in water is also shown (
It is marked in FIG. 2 with an X) mark.

Examples 4 to 11 Amorphous alloy ribbons having the compositions shown in the table were produced in the same manner as in Example 1. The thickness of each ribbon is 14 to 20 μm, and the Tc is as shown in the table.

Each ribbon was wound to form a core, each of which was heat-treated at an appropriate temperature above Tc and quenched with liquid nitrogen.
The AC hysteresis curve was measured using an AC magnetization measuring device under 0e, and from this the coercive force (H
e) and squareness ratio Br/Bt (Br: residual magnetic flux density, B
, : magnetic flux density in a magnetic field of 10e). There was also a problem with magnetostriction. The above results are summarized in the table. As shown in the table, samples with Tc of 230°C or less have a smaller coercive force and a superior squareness ratio than the comparative example, making it possible to achieve high efficiency as a magnetic amplifier, etc.0 [Effects of the Invention] It is clear from the above explanation As shown, the cobalt-based amorphous alloy of the present invention has a high magnetic permeability (Figure 2), a small change over time (Figure 1), and a small coercive force in the high frequency range (Table).
It also has a good squareness ratio and almost zero magnetostriction, making it suitable for saturable reactors for switching power supplies, reactors for semiconductor circuits,
When applied to electromagnetic devices such as step-up transformers for audio, the efficiency of the devices can be improved, which is of great industrial benefit.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the change in magnetic permeability of the alloy of Example 10 over time, where the * mark is for the method of the present invention, and the X mark is for the quenching in water. FIG. 2 is a diagram showing the relationship between TC and μm for various amorphous alloys with different Tc, where the * mark is for the method of the present invention and the X mark is for the case of quenching in water.

Claims (1)

[Claims] 1. A cobalt-based amorphous alloy with high magnetic permeability, characterized by a cue temperature of 230° C. or less and magnetostriction of approximately zero. 2, General formula + (co, -, Ma)ZNtoo-Z(
In the formula, M is Fe, T1+V7Cr+Mn+Ni,
Y+ Zr+Nb, Mo, Hf, 'l'a, w
, Ru, Rh, Pd, Qs, Ir. ptl Represents at least one element selected from the group of rare earth elements: N is 81. B, P, C, Qe. A) represents at least one element selected from the group;
a and z are each 0.03≦a≦0゜30゜65≦2≦
82) The amorphous alloy according to claim 1, having a composition represented by the formula (representing a number satisfying the relationship of 82). 3. An amorphous alloy characterized by heat-treating the amorphous alloy in a temperature range equal to or higher than the Curie temperature and lower than the crystallization temperature of the alloy, and then rapidly cooling the alloy in a cooling medium having a boiling point of 0° C. or lower. manufacturing method. 4. The amorphous alloy has the general formula: (Cot-BMa)zNloo-Z (wherein,
M is Fe, Ti+v, Crl Mnl Ni,
YIZr, Nb, Mo, Hf, Ta, W,
Ru, Rh+ Pd, Os. Represents at least one element selected from the group of metal, pt, and rare earth elements; N is Si, B, P, and C. Ges kl represents at least one element selected from the group; a and Z are each 0.03≦a≦0.30.
65≦Z≦82) The method for producing an amorphous alloy according to claim 3, which has a composition represented by the formula: 65≦Z≦82. 5. The method for producing an amorphous alloy according to claim 3, wherein the cooling medium is either liquid nitrogen or liquid air.