JPS61250162A - Production of amorphous alloy magnetic core - Google Patents

Abstract

PURPOSE:To produce an amorphous alloy magnetic core having a low iron loss in a high-frequency region by winding or laminating a thin amorphous ferrous alloy strip and forming an oxide film layer on the surface thereof to an adequate thickness during the stress relief heat treatment thereof. CONSTITUTION:After the thin amorphous ferrous alloy strip is wound or laminated, the oxide film layer is formed over the entire surface of the above-mentioned strip to >=200Angstrom and <=3,000Angstrom thickness during the stress relief heat treatment thereof, by which the high-frequency magnetic core having the low iron loss is obtd. The above-mentioned heat treatment is preferably executed in a mixed atmosphere composed of an inert gas and oxygen while said atmosphere is forcibly supplied. The above-mentioned atmosphere is adequately formed by setting the mixing molar ratio of the inert gas and oxygen, designated as (100-C):C, at 0.01<=C<=10. The above-mentioned alloy has preferably the positive satd. magnetorestriction expressed by the general formula (Fe1-aMa)100-bXb (M; >=1 kinds among Ti, V, Cr, Mn, Co, Ni, Zr, Nb, Mo, Hf, Ta and W, X; >=1 kinds among Si, B, P, C and Ge, 0<=a<=0.15, 12<=b<=30).

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to a method for manufacturing an amorphous alloy magnetic core.

[Technical background of the invention and its problems]

Conventionally, what is used as the magnetic core of electromagnetic equipment is
There are crystalline materials such as permalloy and ferrite. However, since permalloy has a low resistivity, iron loss in the high frequency range increases. Further, although ferrite has a small iron loss in a high frequency region, it has a drawback that its saturation magnetic flux density is as small as about 5000G.

On the other hand, F e * COI N l * t - base P, C.

B, St, A7. Amorphous alloys containing Ge and the like and having no crystallinity have excellent soft magnetic properties, and are being actively researched.

When manufacturing amorphous alloys, it is common to perform heat treatment to improve magnetic properties such as improving magnetic properties and reducing iron loss. Such heat treatment is carried out at a temperature above the Chieri temperature and below the crystallization temperature, and is usually carried out in nitrogen under reduced pressure (vacuum). Magnetic properties are improved. Furthermore, it has been reported that iron loss is inferior in air heat treatment compared to the above conditions.

[Purpose of the invention]

An object of the present invention is to provide a method for manufacturing an amorphous alloy magnetic core that can significantly reduce iron loss of an amorphous alloy magnetic core.

[Summary of the invention]

The present invention is a method for manufacturing an amorphous alloy magnetic core characterized by winding or forming an iron-based amorphous alloy ribbon.

Here, various magnetic alloys are used as the amorphous alloy.

(Fe, IIMB) Woo-b X bM:Ti
, V, Cr, Mn, Co, Ni, Zr, Nb.

At least one of Mo, Hf, Ta, W: 8i,
B, P, C, Ge, pil! One or more types revealed 0≦a≦
An Fe-based amorphous alloy having positive saturation magnetostriction expressed by 0.15 12≦b≦30 is preferred.

By adding M, the effect of reducing iron loss in the high frequency region and increasing the crystallization temperature can be obtained.Although the addition of a small amount can be effective, it is preferable for practical use that a≧0.01. Also, a) If it is 0.15, Tc is too low.%
Practical soil is not preferred.

In addition, X is an essential element for amorphization, and considering practical thermal stability, a combination of St and B is preferable, and b<
In Edict 12 and b>28, it is difficult to make it amorphous, so
12≦b≦28 is preferable.

Furthermore, 15≦b≦25 is preferable, Si is 2 to 13,
Preferably 2 to 89b are good.

As a method of forming an oxide film during heat treatment.

It is preferable to mix an inert gas such as nitrogen with oxygen to conduct the process in a gaseous atmosphere, and furthermore, by forcibly supplying the gas between the layers of a single turn or a laminated magnetic core, it is possible to obtain a lower iron of -1. losses can be realized.

The ratio of inert gas and oxygen, which is the atmospheric condition, is expressed as a molar ratio (
100-C): C is preferably 0.01≦C≦10. If C<0.01, a significant reduction in iron loss cannot be obtained, and if C)10, the characteristics will rather deteriorate. Preferably 0.01≦C≦5.

Furthermore, it is preferable to forcibly supply the atmosphere between one of the magnetic cores during the heat treatment. This is because an oxide film is formed on the entire ribbon surface of the amorphous alloy that forms the magnetic core, and under normal conditions with almost no convection, a uniform oxide film is formed only on the outer part of the magnetic core. The surface of the ribbon inside the magnetic core is only slightly visible at both ends of the ribbon.
This is because it is difficult to obtain low iron loss. Examples of the atmosphere supply method include a method of blowing the atmosphere from a nozzle-shaped outlet, and a method of absorbing the atmosphere by reducing the pressure in the core.

Regarding the thickness of the oxide film on amorphous alloys, if the thickness of the oxide film is 200A or less, the effect in reducing iron loss is small, and if it is 3000A or more, an oxide film with a thickness within the range of burrs is formed. This is in case it is done.

When the oxide skin 1111 is formed, compressive stress is generated on the ribbon when the temperature tube is lowered to room temperature, and its interaction with magnetostriction causes induced magnetic anisotropy, which impedes the movement of the domain wall. This is thought to be because it reduces eddy current loss, which accounts for most of the total iron loss. Furthermore, preferably 200 to 200
It is OA.

[Embodiments of the invention]

The present invention will be explained below based on examples.

(Example 1) (Pe6.g5Nb o, os) sa with a width I Q mm and an average thickness of 20 am manufactured by a single roll method
8 i 5B12 amorphous alloy ribbon wound, outer diameter 1 g
A toroidal magnetic core with an inner diameter of 12 mm and an inner diameter of 12 mm was obtained. The magnetic core was heat-treated at 460° C. for 30 minutes in an atmosphere having a ratio of nitrogen:oxygen of 99:1 while forcibly blowing the gas onto the magnetic core, and the high-frequency iron loss was measured using a U gate counter. For comparison, heat treatment was performed under similar conditions in nitrogen and air. FIG. 1 shows the iron loss characteristics under the condition of f 5 QKHz. Here, the examples are represented by solid lines, the comparative examples heat-treated in nitrogen by broken lines, and the heat-treated in air by dashed lines.

In the figure, the thickness of the oxide film layer formed on the surface of the amorphous alloy ribbon is added. Note that the thickness of the oxide film layer is a value determined by Auger analysis.

As is clear from FIG. 1, when heat treatment is performed in a mixed gas of nitrogen and oxygen, an appropriate oxide film 1 is formed on the surface of the alloy ribbon, and the iron loss is reduced. It can be seen that whether the thickness of the oxide film layer is too thin or too thick, the effect on reducing iron loss is small.

(Example 2) In the same manner as in Example 1, Fe-based amorphous alloys having several types of compositions were produced, and heat-treated in various atmospheres with the same magnetic core shape. The heat treatment conditions were selected to be optimal for each alloy. These results are summarized in Table 1, and the iron loss values are shown under the conditions of f-50 KHz and Bm-3 KG. It can be seen that low iron loss is obtained when the thickness of the oxide film layer that appears is in the range of 200A or more and 3000A or less.

〔Effect of the invention〕

The present invention provides a high frequency magnetic core with low core loss, and therefore has great industrial value.

[Brief explanation of drawings]

Figure 1 shows f-50KHz for detailed explanation of the present invention.
Iron loss characteristic curve diagram.

Claims (5)

[Claims] (1) After winding or laminating the iron-based amorphous alloy ribbon,
During strain relief heat treatment, a thickness of 200 Å was applied to the entire surface of the alloy ribbon.
A method of manufacturing an amorphous alloy magnetic core characterized by forming an oxide film layer of 3000 Å or less. (2) The method for manufacturing an amorphous alloy magnetic core according to claim 1, wherein the heat treatment is performed in a mixed atmosphere of an inert gas and oxygen. (3) The method for manufacturing an amorphous alloy magnetic core according to claim 2, characterized in that the mixed atmosphere is forcibly supplied during the heat treatment. (4) The mixed atmosphere is 0.01≦C when the mixed molar ratio of inert gas and oxygen is expressed as (100-C):C.
The method for manufacturing an amorphous alloy magnetic core according to claim 2, characterized in that ≦10 is satisfied. (5) The iron-based amorphous alloy has the general formula (Fe_1_-_aM_a)_1_0_0_-_bX_
bM: Ti, V, Cr, Mn, Co, Ni, Zr, Nb
, Mo, Hf, Ta, W at least one type X:Si
, B, P, C, and Ge, as follows: 0≦a≦0.15 12≦b≦30 The method for manufacturing an amorphous alloy magnetic core according to claim 1 .