JPS5914609A - Thermal processing for amorphous magnetic material - Google Patents

Abstract

PURPOSE:To improve permeability in a high frequency region by combining the thermal processings under the rotating magnetic field and vertical magnetic field and by selecting temperature to the specified relation. CONSTITUTION:An amorphous magnetic thin plate 1 is placed under the thermal processing in the rotating magnetic field and vertical magnetic field. In this case, the thermal processing under vertical magnetic field is carried out following the processing under the rotating magnetic field or this sequence may be inverted. In any case, a temperature Ta2 of the thermal processing to be executed first should satisfy the following relation. Namely, the temperature Ta1 is 300 deg.C or higher and is not higher than the Curie temperature Tc of amorphous magnetic material, while the temperature Ta2 is equal to Ta1 or lower and is 250 deg.C or higher but 350 deg.C or lower. Thereby, an inductive magnetic anisotropy can be controlled on the basis of three dimension and permeability in a frequency region as high as 10kHz or higher can be improved.

Description

[Detailed description of the invention] The present invention relates to a method for heat treating an amorphous magnetic material.

Amorphous magnetic alloys manufactured as soft magnetic materials generally have a large coercive force and a low magnetic permeability in the as-manufactured state. To use it as a soft magnetic material, it is usually necessary to heat treat it to increase its magnetic permeability. Conventionally, heat treatment methods for improving the magnetic permeability of amorphous magnetic alloys include:
Mainly two methods are known. The first method is applied to an amorphous magnetic alloy whose crystallization temperature Tx is higher than the Curie temperature Tc. This is a heat treatment method in which the material is held for a period of time and then rapidly cooled. The second method is called rotating magnetic field heat treatment, which involves rotating a sufficiently strong magnetic field within the main surface of the amorphous magnetic alloy thin plate at a temperature lower than the crystallization temperature Tx or lower than the crystallization temperature Tc. It is. This method can produce the same effect even when rotating an amorphous magnetic alloy thin plate in a static magnetic field. In the case of high magnetic flux density materials desired as amorphous magnetic alloys, the crystallization temperature Tx is often lower than the Curie temperature Tc, so the second method (heat treatment in a rotating magnetic field) is used instead of the first method. will be applied. However, these heat treatment methods have low magnetic permeability in a high frequency range.

In view of the above-mentioned points, the present invention provides a method for heat treating an amorphous magnetic material, which improves the magnetic permeability particularly in a high frequency range of about 10 kliz or more.

In the present invention, heat treatment is performed on an amorphous magnetic thin plate in a magnetic field that rotates within the main plane of the thin plate relative to the thin plate, or by rotating the magnetic field within the main plane of the thin plate. The thin plate is subjected to so-called perpendicular magnetic field heat treatment performed by rotating the thin plate in a static magnetic field, and heat treatment performed in a magnetic field that is almost perpendicular to the main surface of the thin plate and strong enough to saturate the thin plate, that is, so-called perpendicular magnetic field heat treatment. Become. In this case, the order of heat treatment may be such that the amorphous magnetic thin plate is subjected to heat treatment in a rotating magnetic field and then heat treated in a vertical magnetic field, or vice versa, after heat treatment is performed in a perpendicular magnetic field, Heat treatment in a rotating magnetic field may also be performed. Therefore, in any heat treatment order, the temperature +11a1 of the first heat treatment and the temperature Ta2 of the next heat treatment satisfy the following relationship. Temperature l1la1
is 300°C or higher and the Curie temperature Tc of the amorphous magnetic material
The temperature 1゛a2 is lower than 'l'a1 and is 250
Select a temperature between ℃ or higher and 350'C or lower. That is, 300°C<, 'I'al <TC 250°C<Ta2 <350°C Ta2<Ta1 If the temperature Ta1 is lower than 300°C, the processing time will be long and the effect of strain removal will not be improved, and the temperature will be lower than the Curie temperature Tc. At high temperatures, the object to be treated loses its magnetism, so it cannot be heat-treated in a magnetic field. If the temperature 'l'a2 is as low as 250° C., the induced magnetic anisotropy in the direction of the post-processing will be sufficiently produced, and the processing time will be long, so it is not very meaningful industrially. Also, the temperature Ta2 is 3
At temperatures as high as 50'O, the induced magnetic anisotropy in the direction of post-treatment is too strong and the permeability decreases.

Normally, many amorphous magnetic materials develop induced magnetic anisotropy when heat treated in a magnetic field. In the present invention, as described above, heat treatment in a rotating magnetic field and heat treatment in a perpendicular magnetic field are combined, and Kx is the induced magnetic anisotropy constant in the x direction. Kz: Induced magnetic anisotropy constant in the z direction.
, indicates the z direction.

By doing so, the induced magnetic anisotropy in the thin plate of amorphous magnetic material can be almost eliminated, and the magnetic permeability in a high frequency range of 10 kHz or higher can be improved. It should be noted that, on the contrary, it is also possible to provide induced magnetic anisotropy in an appropriate direction.

On the other hand, in general, in heat treatment, the higher the treatment temperature, the faster the structural relaxation. In addition, when heat treatment is performed twice,
The first treatment temperature 'l'al is set to be lower than the crystallization temperature Tx ('I'at < Tx), and the second treatment temperature is set to 1.
When ゛a2 is set to a lower temperature than the crystallization temperature Tx (Ta2<Tx), when the second heat treatment is performed at 'l'2>'l'a1, the structural relaxation occurs when '1'2 < Ta1. It's significantly faster than that.

Since induced magnetic anisotropy is a type of structural relaxation of amorphous magnetic materials, the above two types of magnetic field heat treatment are performed to produce the required induced magnetic anisotropy, and 10 kl (high frequency To improve the permeability in the area l1182<'l'a
The first and second heat treatments are carried out for an appropriate time. This allows for easy implementation with less variation in characteristics.

Next, examples of the present invention will be described.

Example (1) A low magnetostrictive amorphous magnetic alloy thin plate having a composition of Fes C075844816 (atomic ratio) (however, the crystallization temperature Tx was 420
℃, Curie temperature Tc is 570℃, plate thickness 18 ptn
) Magnetic field Ha parallel to the plate surface with respect to K: 2.4 k
Oe, rotation speed: Ta1 in a rotating magnetic field of 1100 rp:
The temperature was maintained at 370'Q, heat treated for 30 minutes, and then a magnetic field of 13.8 koe 1ia was applied perpendicular to the surface of the thin plate.
While applying 'l'al, keep the temperature Ta2 lower than 1.
Heat treatment was performed for 0 minutes. Figure 2 shows the second treatment temperature.
Frequency In of each magnetic permeability μ′ when changing 'a2' Characteristic t
Shown. In the figure, curves (I), (II), +1
3, GV), the processing temperature Ta2 was 241°C and 26°C, respectively.
This is the case of 1'01275°C and 305°C.

Example (2) Amorphous magnetic alloy thin plate with the same composition as Example (1) (plate thickness 3
9 μm) was heat-treated for 30 minutes while applying a magnetic field 14a of 13.8 kOe perpendicular to the plate surface while maintaining the temperature Ta1 = 370'Q, and then a magnetic field Ha: 2.9 μm parallel to the plate surface was applied. 4 koe, rotation speed = 10Orpm
In the rotating magnetic field of 'l'a1, there is a lower temperature 'J'a2 K
Heat treatment was performed for 10 minutes. FIG. 3 shows the frequency characteristics of each magnetic permeability .mu.' when the second treatment temperature 1.a2 was changed. In the same figure, curves (a) and (b) show that Ta2 is 30
This is the case at 0°C and 332°C. Also, curve [C] is the first
In the case of only the second vertical magnetic field treatment, the curve (dl is the rotating magnetic field treatment only (temperature Ta: 370 oC, treatment time Ta: 10 minutes)) 1 curve (el is the case of the manufactured one (untreated) It is.

As is clear from the above examples, when heat treatment in a rotating magnetic field and heat treatment in a vertical magnetic field are combined and temperatures Ta1 and Ta2 are selected in the above-mentioned relationship, the induced magnetic anisotropy is controlled three-dimensionally, and the heat treatment in a rotating magnetic field is Magnetic permeability in a high frequency range of l Q kHz or more is improved compared to the case of heat treatment or no treatment.

Note that the present invention is also effective for amorphous magnetic alloys whose crystallization temperature Tx is higher than the Curie temperature Tc.

[Brief explanation of drawings]

FIG. 1 is a diagram showing coordinates and the direction of axis 1 used for explaining the present invention, and FIGS. 2 and 3 are illustrations of embodiments (1) and (2), respectively.
) is a frequency characteristic diagram of magnetic permeability obtained by heat treatment. (1) is a thin plate of amorphous magnetic material. Figure 11 Continued from page 1 0 Inventor Kazuhiko Hayashi Sony Corporation Central Research Laboratory, 174 Fujitsuka-cho, Hodogaya-ku, Yokohama City

Claims (1)

[Claims] A heat treatment method for a thin plate of amorphous magnetic material, including heat treatment performed in a magnetic field that rotates within the main surface of the thin plate relative to the thin plate, and heat treatment performed in a magnetic field approximately perpendicular to the main surface of the thin plate. The first heat treatment is performed at a temperature of 300°C or higher and below the Curie temperature of the amorphous magnetic material, and the second heat treatment is performed at a lower temperature than the first heat treatment at a temperature of 250°C or higher and 350°C or lower. Characteristic heat treatment method for amorphous magnetic materials.