JPS6280277A - Thin amorphous alloy strip having superior constant magnetic permeability - Google Patents

Abstract

PURPOSE:To improve the constant permeability of a thin amorphous alloy strip in a wide range by forming a prescribed insulating film on the surface of the strip having a positive magnetostriction constant so that compressive force is applied in the longitudinal direction of the strip. CONSTITUTION:The titled thin amorphous alloy strip is obtd. by forming an insulating film for applying compressive force on the surface of a thin amorphous alloy strip having a positive magnetostriction constant. The insulating film has 1-5mum thickness and is formed by coating the surface of the strip with an aqueous soln. of lithium silicate having 3-4 molar ratio of SiO2/Li2O, baking the soln. and carrying out heat treatment at 250 deg.C - the crystallization temp.

Description

Detailed Description of the Invention (Industrial Application Field) The technical content described in this specification regarding an amorphous alloy ribbon with excellent constant magnetic permeability is to By forming an insulating coating capable of applying a compressive force to the magnetic field, the constant magnetic permeability range is advantageously expanded.

In the magnetization curve, a material whose magnetic flux density B changes linearly with the magnetic field strength H and whose magnetic permeability μ is almost constant regardless of the magnitude of the applied magnetic field strength H is called a constant magnetic permeability material. call,
It is used in filters for communication equipment, loading wires, thyristor protection circuits, pulse transformers, etc.

(Conventional technology) As a constant magnetic permeability material, conventionally, 45%N+ -30%F
e-25%Co verminbar and 50%Ni-50%F
Although e-isobalm and the like are known, the constant magnetic permeability range of all these is limited to a narrow range of 5 to 100 e.

In this regard, as a method for manufacturing a material that exhibits constant magnetic permeability over a wide range, JP-A-57-169207 discloses a method of forming an oxide film on the surface of an Fe-based amorphous alloy ribbon. No. 57-169208 proposes a method of forming an oxide film of A1 on the surface of an Aβ-Fe-based amorphous alloy strip.

(Problem to be solved by the invention) However, in many cases, amorphous alloys become brittle due to annealing, so when expanding the range of constant magnetic permeability by the above method, an oxide film is formed after forming the magnetic core. For example, when making a wound core as a magnetic core, the degree of progress of the oxidation reaction and the thickness of the oxide film vary depending on the winding condition of the ribbon. The problem remained that variations in characteristics occurred.

The present invention aims to advantageously solve the above-mentioned problems and to propose an amorphous alloy ribbon that can stably exhibit constant magnetic permeability over a wide range.

(Means for solving the problem) The inventors have discovered that constant magnetic permeability appears when a material with uniaxial magnetic anisotropy is magnetized in the direction of the hard magnetization axis, and that an amorphous magnetic alloy Focusing on the large induced magnetic anisotropy, we conducted various experiments to make the longitudinal direction of the amorphous alloy ribbon the axis of difficulty in magnetization by applying an external force to the ribbon.

As a result, when a compressive force is applied in the longitudinal direction of an amorphous alloy ribbon that has a 180-degree magnetic domain wall, an easy axis of magnetization in the longitudinal direction of the ribbon, and a positive magnetostriction constant, the 90-degree magnetic domain wall was formed, and the longitudinal direction of the ribbon was found to be the axis of difficult magnetization. In this regard, in alloys with zero magnetostriction such as CO-based amorphous alloys, there was no change in the domain wall due to external stress as described above.

Therefore, if compressive force can be applied to an amorphous alloy ribbon with a positive magnetostriction constant in the longitudinal direction of the ribbon by some means, constant magnetic permeability should be obtained when the ribbon is magnetized in the longitudinal direction. be.

Therefore, the inventors next investigated various means for applying compressive force to the ribbon, and found that an extremely effective means for such a method is to coat the surface of the ribbon with an insulating film that applies compressive force. I gained some knowledge.

This invention is based on the above knowledge.

That is, the present invention comprises an amorphous alloy ribbon having a positive magnetostriction constant, which is provided with an insulating coating that imparts compressive force on the surface of the amorphous alloy ribbon.
This is an amorphous alloy ribbon with excellent constant magnetic permeability.

In this invention, the insulating film to be formed on the surface of the ribbon is coated with a lithium silicate aqueous solution having a SiO2/Li2O molar ratio of 3 to 4 and baked on the surface of the base ribbon. Film thickness obtained through heat treatment in a temperature range of 1.0 to 5.degree. C. or above and below the crystallization temperature.
An insulating coating with a compressive force of 0 μm is particularly advantageously suitable.

Furthermore, examples of amorphous alloy ribbons having a positive magnetostriction constant that can be suitably used in the present invention include the following.

The main component is Fe and contains one or more of B, Si, and C in the range of 15 to 20 at%, and the typical composition is Fe7sBsSi +
2C++ Fe7sB+.

5i12 and Fe 77 at 2 Si + oc
+ etc. Note that in this type of alloy, the magnitude of the magnetostriction constant is approximately proportional to Fei in the alloy.

This invention will be specifically explained below.

First, the experimental results that formed the basis of this invention will be explained.

fil O-)'v method, l”e 78B1 o
Width with composition si + 2: somm, thickness 227
A μm-sized amorphous alloy ribbon was produced.

Then, on the surface of this thin strip, S! 02/L, I 2
Lithium silicate aqueous solution whose molar ratio of 0 was adjusted to 3.5 (
Lithium silicate LSS-35) manufactured by Sansan Kagaku Co., Ltd. was applied and baked at 200° C. for 3 minutes. The resulting coating thickness was approximately 3μ
It was m.

The amorphous alloy ribbon at this stage was highly ductile and not brittle.

Next, when heat treatment was performed at 350°C for 1 hour, the first
As shown by the B-8 curve in the figure, constant magnetic permeability was obtained over a wide range up to approximately 250e.

Here, 5i02/Li in lithium silicate aqueous solution
If the molar ratio of 20 is less than 3, the water resistance and moisture absorption resistance of the obtained film will be poor, while if it exceeds 4, the adhesion of the film will deteriorate, especially when the film thickness is close to 5 μm. Since even the formation of a film becomes difficult, the molar ratio of 5102/Li 20 must be limited to a range of 3 to 4.

In addition, in this invention, after applying the above-mentioned coating treatment liquid to the surface of the base ribbon and baking it,
It is important to perform the heat treatment in the crystallization temperature to crystallization humidity range.

This is because, through such heat treatment, the axis of easy magnetization of the base ribbon is aligned in the longitudinal direction and it has uniaxial magnetic anisotropy, while at the same time the insulating film baked on the surface of the base ribbon is sufficiently hard. This is because a compressive force is applied to the ribbon as a result of this, and as a result, the longitudinal direction of the ribbon becomes an axis of difficult magnetization and exhibits constant magnetic permeability.

If the heat treatment temperature is less than 250°C, dehydration will not proceed sufficiently, making it difficult to harden the film, and therefore, it will not be possible to apply a satisfactory compressive force.On the other hand, if it exceeds the crystallization temperature, it will become amorphous. Since the temperature cannot be maintained and the desired magnetic properties cannot be obtained, the heat treatment temperature is limited to 250° C. to crystallization temperature and crystal humidity temperature.

Note that if the thickness of the surface coating is less than 1.0 μm, it is difficult to apply a satisfactory compressive force to the ribbon;
．． If it exceeds 0 μm, the adhesion of the film is likely to deteriorate, so the film thickness should be 1. It is desirable to set it to about θ to 5.0 μm.

(Function) The reason why the range exhibiting constant magnetic permeability is advantageously expanded by this invention is that compressive force is applied to the ribbon by the insulating coating formed on the surface of the amorphous alloy ribbon, and is the axis of difficult magnetization.

Note that the heat treatment for hardening the coating may of course be performed before assembling the magnetic core, but from the viewpoint of ease of handling, it is more preferable to perform the heat treatment before assembling the magnetic core. Even if heat treatment is applied after the magnetic core is assembled, a coating has already been baked onto the surface of the ribbon, although it has not hardened, so variations in characteristics due to differences in film thickness will not occur as in the past. do not have.

(Example) Example 1 Fe 7 [I B + o S i l 2 (DI
A-formed non-a'R alloy ribbon (crystallization temperature: 540℃
) with a molar ratio of Si 02 /Li 20 of 3.
After applying the lithium silicate aqueous solution prepared in step 5,
Baked at 00°C for 2 minutes. The thickness of the film obtained at this time was about 4.0 μm. Then, in a nitrogen gas stream,
Annealing treatment was performed at 80°C for 1 hour.

When the magnetization curve of the ribbon thus obtained was examined, it exhibited constant magnetic permeability up to about 35 Qe.

Example 2 An amorphous alloy ribbon with an insulating coating was prepared in the same manner as in Example 1 except that the dry film thickness was 2.0 μm.

The ribbon thus obtained exhibited constant magnetic permeability up to about 2008.

Comparative Example 1 An amorphous alloy ribbon with an insulating coating was prepared in the same manner as in Example 1 except that the dry film thickness was 0.1 μm. The range of constant magnetic permeability of the obtained ribbon was It did not even reach 3Qe.

(Effects of the Invention) Thus, according to the present invention, it is possible to easily obtain an amorphous alloy ribbon exhibiting constant magnetic permeability over a significantly wider range than in the prior art.

[Brief explanation of drawings]

FIG. 1 is a B-H curve diagram of an amorphous alloy ribbon with an insulating coating according to the present invention.

Claims (1)

[Claims] 1. An amorphous alloy ribbon with excellent constant magnetic permeability, comprising an amorphous alloy ribbon with a positive magnetostriction constant and an insulating coating that imparts compressive force on the surface thereof. 2. Compressive force imparting type insulation coating is SiO_2/Li_2
A lithium silicate aqueous solution with an O molar ratio of 3 to 4 was applied to the surface of the base ribbon and baked, and then
The amorphous alloy ribbon according to claim 1, which is a film having a thickness of 1.0 to 5.0 μm obtained through heat treatment in a temperature range of not less than 0.degree. C. and not more than the crystallization temperature.