JPS6265403A - Improving magnetic characteristics of amorphous alloy thin band - Google Patents

Abstract

PURPOSE:To realize improvement of magnetic characteristics, particularly of a characteristic in iron loss, as well as improvement of layer resistance, without danger of causing fragility and decrease in space factor, by forming a ceramic thin film by an evaporation method under an external magnetic field applied in the longitudinal direction of an amorphous alloy thin band having a positive constant of magnetic strain. CONSTITUTION:An amorphous alloy thin band is produced from a molten alloy bath by single rolling method. A quenched thin band of such composition, because of its saturated magnetic strain, can be extended with an external magnetic field applied. And, a SiO2 film is formed on this quenched thin band by ion plating method in depressurized argon gas and under the application of the external magnetic field. Such a film-formed treatment enables magnetic domain to be oriented 180 deg. in parallel with the longitudinal direction of the thin band and the thin band to be expanded in the longitudinal direction. Magnetic characteristics can be improved by forming a ceramic thin film on the surface of the thin band and fixing the thin band, under such a condition. Because the thin band is not heated, there is no danger of causing fragility and crystalization in the amorphous alloy. Besides, because of decrease in stress sensitivity of the amorphous alloy thin band, a superior characteristic in iron loss can be maintained.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a method for improving the magnetic properties of an amorphous alloy ribbon, and in particular, to a method for improving the magnetic properties of an amorphous alloy ribbon, and in particular to a method for forming a surface coating on the surface of the ribbon. This is intended to advantageously improve magnetic properties, especially iron loss properties.

(Prior art) Molten alloy such as Pa-B-St system is heated at 10S to 10b℃/
When rapidly solidified at a cooling rate of about seconds, the plate thickness is 20 to 50.
An amorphous alloy ribbon of about μm size is obtained. Such amorphous alloy ribbons have excellent soft magnetism and exhibit particularly low core loss, so they are considered to be a powerful competitive material to grain-oriented silicon steel sheets, which are currently used as core materials for transformers. Attention has been paid.

By the way, such amorphous alloy ribbons still cannot exhibit sufficiently satisfactory magnetic properties in the rapidly cooled state, so conventionally they are annealed in a magnetic field at a temperature of 350 to 400°C to release internal stress and improve magnetic properties. The aim was to improve magnetic properties by inducing anisotropy.

However, when magnetic field annealing is applied as described above, the ribbon becomes thinner during the annealing process, and this, coupled with the fact that the ribbon is already highly sensitive to stress, tends to lead to deterioration of iron loss, especially when bending stress is applied. Although this is not a major problem in the production of the core, there is a problem in that it requires extremely careful handling during the winding and assembly processes of the toroidal core.

On the other hand, conventionally, such amorphous alloy ribbons are wound to form a core without being coated with an insulating film for glabellar insulation, and then assembled into a transformer, which is extremely difficult. This is because the crystalline alloy itself has a high specific resistance and the ribbon has a large surface roughness, so when laminated, the resistance between the eyebrows was relatively high and the effect on the total loss was small.

However, with recent advances in manufacturing technology for amorphous alloy ribbons, the surface has become smoother and the space factor has improved, but this has also led to a decrease in glabellar resistance and increased eddy current loss when processed into a core. There is a tendency to increase. Therefore, in recent years, it has become necessary to coat amorphous alloy ribbons with an insulating coating in order to reduce eddy current loss and ultimately total loss.

(Problems to be Solved by the Invention) As an insulating coating treatment, a phosphate-based insulating coating treatment used for silicon steel sheets can be considered. -a requires around 400° C. for baking and tends to cause embrittlement and crystallization of the amorphous alloy, so it is not preferable to use it as is as an insulating coating for an amorphous alloy ribbon.

On the other hand, JP-A-58-109171 proposes the use of an electron beam curable resin coating in order to avoid embrittlement of the amorphous alloy ribbon due to heating. However, although such an organic film can improve the glabella resistance, it is not effective in fully demonstrating the magnetic properties of the amorphous alloy. If annealing is performed, not only will the amorphous alloy become brittle as described above, but the organic resin will also carbonize during the annealing, making it impossible to maintain even the desired glabellar resistance.

If the amorphous alloy ribbon can exhibit its original properties without causing embrittlement, and if it can increase the resistance between the eyebrows by forming an insulating film on its surface, it would be of great industrial significance. big.

This invention was developed in view of the above circumstances, and it forms a surface coating on an amorphous alloy ribbon without heating it.
The purpose of the present invention is to propose a method for improving the magnetic properties of an amorphous alloy ribbon, which not only improves the glabellar resistance but also allows the amorphous alloy itself to fully demonstrate its excellent magnetic properties.

(Means for solving problems) First, the background to the elucidation of this invention will be explained.

FIG. 1 shows the relationship between tensile stress and iron loss characteristics when a tensile force is applied in the longitudinal direction of a rapidly cooled Fe-B-3t amorphous alloy ribbon.

As is clear from the figure, the iron loss is significantly reduced by adding tension.

By the way, in order to elongate an amorphous alloy ribbon in its longitudinal direction, in addition to applying tension, it is also necessary to apply an external magnetic field in its longitudinal direction, especially for those with a positive magnetostriction constant. Able to achieve purpose.

Therefore, by applying an external magnetic field in the longitudinal direction of the ribbon or applying tension to stretch the ribbon, a surface coating with high adhesion and rigidity can be applied to the surface of the ribbon without heating. If you can fix the thin strip as it is by applying
Even if the external magnetic field and/or external tension is released, the state in which tension is applied in the longitudinal direction of the ribbon can be maintained, which is extremely advantageous for improving iron loss characteristics.

As a result of repeated research on surface treatment methods that satisfy these requirements, we have found that applying a surface coating using ceramics as a coating material by ion blasting, etc. is extremely effective in achieving the desired purpose. Ta.

This invention is based on the above knowledge.

That is, this invention forms a ceramic thin film by vapor deposition on the surface of an amorphous alloy ribbon having a positive magnetostriction constant under the application of an external magnetic field in the longitudinal direction of the alloy ribbon, and sometimes further coats the ceramic thin film on the surface of the alloy ribbon. This is a method for improving the magnetic properties of an amorphous alloy ribbon by forming an electrically insulating coating over a thin film.

In addition, this invention applies an external magnetic field in the longitudinal direction of an amorphous alloy ribbon having a positive magnetostriction constant, and
An amorphous alloy ribbon formed by forming a ceramic thin film on the surface of the alloy ribbon by vapor deposition under a tension of 8 mm, and sometimes further forming an electrically insulating coating on the ceramic thin film. This is a method for improving magnetic properties.

As the vapor deposition method in this invention, vacuum vapor deposition method, ion blating method, sputtering method, CVD method, etc. are particularly advantageously suitable.

The experimental results that formed the basis of this invention will be explained below.

Fev. From a molten alloy of B+oSi+z composition, width: 53. An amorphous alloy ribbon having a thickness of 30 μm was produced. Since a quenched ribbon having such a composition has a large saturation magnetostriction λ, it can be elongated by applying an external magnetic field as shown in FIG.

Therefore, the magnetization of this quenched ribbon is 1.4T (1!
A 0.4 .mu.-thick Si0g film was formed by Holloei cathode ion blating in a reduced pressure argon gas of about 10" torr under the application of an external magnetic field such that the sum magnetization: 1.54 T). The treatment time here was approximately 20 seconds, and the amorphous alloy did not become brittle due to this formation treatment.

When this amorphous alloy ribbon with an insulating thin film was used as a toroidal core with a diameter of 6 cll and the iron loss was measured, it was found to be 50 Hz.
, Iron loss Wll/All at 1.3T is 0.26W Hg
and that of the thin strip as it is quenched is 0.33W/kg.
It was much better than it was.

In addition, when we attempted similar measurements on an amorphous alloy ribbon obtained by applying not only an external magnetic field but also a tension of 2 kg/m'' during the ion blating of the above-mentioned Sin film, we found that the iron loss was w + szs. was reduced to 0.19W/+r.

Furthermore, when each of the above ribbons was treated with a phosphate-based or chromate-based insulating coating, the iron loss characteristics were improved to 0.01 to 0.
0.3 W/kg, and the corrosion resistance and oil resistance were also significantly improved.

In this invention, an amorphous alloy ribbon having a positive magnetostriction constant is targeted. This is because a thin ribbon with a magnetostriction constant of 0 or negative does not elongate even when a magnetic field is applied.
Therefore, even if a surface coating is formed, the effect of imparting tension to the ribbon cannot be expected. As the amorphous alloy used in this invention, a Fe-B-Si alloy having a large saturation magnetostriction λS such as 25 to 30×10 −′ is advantageously suitable.

The magnitude of the magnetic field applied to the ribbon is preferably such that the magnetization of the ribbon is 80% or more of the saturation magnetization.

This is because if the external magnetic field is smaller than this, it is difficult to impart sufficient elongation to the ribbon that is effective for improving magnetism.

As the method for forming the ceramic thin film, any method may be used as long as the thin film can be formed without heating the ribbon, and in addition to the above-mentioned ion blasting, vacuum evaporation, sputtering, CVD, etc. are advantageously suitable. It's confirmed. Particularly when electron beam heating was used, high-speed thin film deposition was achieved.

Next, as a coating material, 5iop, AI! 03+
Inorganic oxides such as Tilt, TiN, ZrN, 5
Ceramics such as nitrides such as isN4, carbides or borides such as TiC and SiC can be suitably used.

In this respect, organic coatings and semi-organic coatings are not suitable because they lack rigidity and cannot apply tension to the ribbon.

In addition, the amount of tension applied to the ribbon is 0.1 to 10 kg.
/ Sodium m''. This is because if the added tension is less than 0.1 kg/m, the contribution to improving the magnetic properties is extremely small, while if it exceeds 10 kg/m, the film will not be continuous. This is because there is a high possibility that troubles such as breakage may occur during processing.

Furthermore, regarding the surface coating thickness, whether it is a ceramic thin film only or an overcoat insulation coating, if the film thickness is less than 0.05μ, it will not be possible to apply sufficient tension and the resistance between the eyebrows will be insufficient. On the other hand, if it exceeds 2 .mu.m, it is not preferable because it causes a decrease in the space factor, so it is desirable that the film thickness is 0.05 to 2 .mu.m.

When forming an insulating film on a ceramic thin film, if the processing temperature exceeds 300°C, there is a high risk of embrittlement of the amorphous alloy ribbon. It is important to form such an insulating coating, and suitable examples include a silica coating formed by coating ethyl silicate, an alumina coating formed by coating an aqueous alumina sol solution, and a phosphate coating.

(Function) When an external magnetic field is applied in the longitudinal direction of an amorphous alloy ribbon with a positive magnetostriction constant, the magnetic field is
When the fi sections are aligned, the ribbon is elongated in the longitudinal direction, and in this state, a ceramic thin film is formed on the surface of the ribbon to fix the ribbon, thereby improving the magnetic properties.

Furthermore, since the ribbon is not heated during the formation of the ceramic thin film, there is no risk of embrittlement or crystallization of the amorphous alloy.

Furthermore, by coating the amorphous alloy thin film with a ceramic thin film, the stress sensitivity of the amorphous alloy ribbon is reduced, so that excellent iron loss characteristics are maintained even when assembled into the core of a transformer.

(Example) Example 1 Width: 201. Thickness: 25tta Fe4tB*Si+4
In the longitudinal direction of the amorphous alloy ribbon, the magnetization of the ribbon is 1.45.
T (saturation magnetization: 1.53T) under the application of an external magnetic field, A I with a thickness of 0.2 μm, 0. A film was applied.

The space factor of the obtained amorphous alloy ribbon with the AlzCh thin film was 81.3%, and the iron loss W l 3zs. is 0.2Ibg
Met.

Next, a magnesium phosphate-based insulating coating treatment liquid was applied, and then baked at 250°C to form an insulating coating with a thickness of 0.3 μm.

By forming such an insulating film, the space factor became 81.1%, but the iron loss W. could be reduced to 0.17 W/kg, and the amorphous alloy ribbon did not become brittle due to such low temperature baking.

The space factor of the above-mentioned bare ribbon after rapid solidification is 81.
5%+W+315° was 0.34 cm.

Example 2 The same amorphous alloy ribbon as in Example 1 was used, but the magnetization of the ribbon was 1.4.
By applying an external magnetic field of 57 and applying a tension of 3 kg/nl, 0.3
A Tic + TiN film of μ■ thickness was deposited.

The space factor of the obtained amorphous alloy ribbon with a ceramic thin film was 81.4%, and the iron loss was W. is 0.16 hag
Met.

Next, an alumina sol coating solution was applied and baked at 200°C to form an insulating film with a thickness of 0.15 μm.

By forming such an insulating film, W+3/80 becomes 0.14.
W/kg.

(Effects of the Invention) Thus, according to the present invention, it is possible to significantly improve the magnetic properties, especially the iron loss properties, and improve the glabella resistance without causing embrittlement or a decrease in the space factor of the amorphous alloy ribbon. It can be realized by

[Brief explanation of the drawing]

Figure 1 shows the additional tension and iron loss W, ! when a tensile force is applied to an amorphous alloy ribbon. ,,. Figure 2 is a graph showing the magnetization characteristics of magnetostriction.

Claims (1)

[Claims] 1. A ceramic thin film is deposited on the surface of an amorphous alloy ribbon having a positive magnetostriction constant by vapor deposition under the application of an external magnetic field in the longitudinal direction of the alloy ribbon. A method for improving the magnetic properties of an amorphous alloy ribbon. 2. Applying an external magnetic field in the longitudinal direction of an amorphous alloy ribbon having a positive magnetostriction constant, deposit a ceramic thin film on the surface of the alloy ribbon by vapor deposition, and then overlay it on the ceramic thin film. A method for improving the magnetic properties of an amorphous alloy ribbon, the method comprising forming an electrically insulating film on the amorphous alloy ribbon. 3. Applying an external magnetic field to the longitudinal direction of an amorphous alloy ribbon with a positive magnetostriction constant and applying a tension of 0.1 to 10 kg/mm^2, ceramics are deposited on the surface of the alloy ribbon by vapor deposition. A method for improving the magnetic properties of an amorphous alloy ribbon characterized by forming a thin film thereon. 4. Applying an external magnetic field to the longitudinal direction of an amorphous alloy ribbon with a positive magnetostriction constant and applying a tension of 0.1 to 10 kg/mm^2, ceramics are deposited on the surface of the alloy ribbon by vapor deposition. A method for improving the magnetic properties of an amorphous alloy ribbon, comprising forming a thin film thereon and then forming an electrically insulating film over the ceramic thin film.