JPS5934779B2 - Magnetic field heat treatment method for amorphous metal bodies - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for modifying magnetic lunate in amorphous metals.

In particular, it relates to a novel method for continuously heat-treating amorphous metals in large quantities in a magnetic field. In a normal solid state, metals are crystals with long-period order in which atoms are regularly arranged, but when special manufacturing methods such as rapid cooling from a molten state are used, a disordered atomic structure similar to that in a liquid state can be obtained. has been revealed as a result of recent research.

Such metals are called amorphous metals. Amorphous metals have very different thermal, electrical, magnetic, and mechanical properties from ordinary metals, and some have superior properties that crystalline metals do not have. For example, alloys consisting of ferromagnetic metallic elements such as Fe, Co, and Ni and semimetallic elements such as B, P, Si, and Aι tend to take an amorphous state, and the amorphous alloy has relatively good soft magnetic properties. It is known that it has the following characteristics. Recently, there have been many attempts to utilize this property to improve the performance of conventional electromagnetic devices. For example, it can be applied to transformers, etc. to make them smaller, or applied to magnetic heads, etc.
Attempts have been made to obtain good frequency characteristics and linearity. However, since amorphous metals are obtained by a rapid cooling method, if they remain in a rapidly cooled state, they will have large strains and their magnetic properties will not be very good.

In addition, its characteristics vary widely and change over time.
In order to eliminate such drawbacks, attempts have been made to apply known methods and techniques for ordinary crystalline metals.
For example, it seems that the above-mentioned drawbacks can be eliminated by heat treatment at an appropriate temperature and time. However, it has been found that mere heat treatment does not necessarily improve the properties, but rather tends to cause deterioration. According to recent research results, if an amorphous metal is magnetically saturated and heat treated,
It was found that the magnetic properties were significantly improved.

The present invention is an industrial method for supplying a large amount of material with excellent magnetic properties by magnetically saturating an amorphous metal and subjecting it to heat treatment.

A conventional laboratory method for magnetically saturating a sample and subjecting it to heat treatment is shown in FIG. When a sample has excellent soft magnetic properties, the demagnetizing field generated by the sample cancels out most of the external magnetic field, so a large external magnetic field is required to achieve magnetic saturation, and the positional relationship between the sample and the magnetic field is also adjusted to minimize the demagnetizing field. Special consideration is required, such as making sure that the magnetic field is small. In order to apply a large external magnetic field, a very large electromagnet is required, and if a heating device is included for heat treatment in the magnetic field, the device becomes large-scale. Moreover, it is not possible to process a large amount of samples continuously. In FIG. 1, which shows the conventional method, the symbol 1 is an electromagnet, 2 is a heating device, and 3 is a sample.

In order to satisfy the rapid cooling conditions for amorphous metals, it is usually only possible to obtain sample shapes with a thickness of about 100 μm or less, such as thin wires, thin plates, or ribbons. Although it is possible to reduce the demagnetizing field in the case shown in the figure in which the sample is arranged parallel to the sample, it is clear that continuous heat treatment of a long sample is difficult with such an arrangement. The present invention is an industrial method for performing heat treatment in a magnetic field, which improves the drawbacks of the conventional methods described above.

FIG. 2 is a diagram showing the principle of the present invention. Symbol 4 is a conducting wire for passing a large current, 5 is a heating device, and 6 is a sample spread around the conducting wire. A magnetic field created by a large current flowing through the conductor acts on the sample, but due to the symmetry between the sample and the magnetic field, the demagnetizing field becomes zero in this arrangement, making it easy to magnetically saturate the sample.One conductor acts as a large electromagnet. to act in place of. Hereinafter, the present invention will be explained in detail with reference to Examples.

The sample is an amorphous alloy (COQ94FeO.O6)82B,8. After weighing, melting and alloying each element,
It is melted and squirted onto a copper roll with a diameter of 50 mm that rotates at a high speed of approximately 10,000 rpm. Approximately 20μ thick
A long amorphous alloy tape of m length was obtained. Such a method is
This is a very common method for manufacturing amorphous metals, usually called the single roll method. FIG. 3 is a diagram showing the magnetization characteristics of the amorphous alloy tape thus obtained in the rapidly cooled state. The main problem is the Lukhausen effect, which causes loss and noise, making it impossible to put it to practical use as it is. FIG. 4 shows the magnetization characteristics of a sample subjected to heat treatment in a magnetic field according to the method of the present invention.

A copper rod with a diameter of 4 mm was used as the conductor, and about 50
A current of A was applied. About 1 m of the sample was wrapped around a copper rod for about 100 turns, and heat treated at 230° C. for 30 m. The magnetic field created by the current is several 100 e('), but since the demagnetizing field is zero, the sample is magnetically saturated and the sample properties are improved. In other words, the Barkhausen effect disappears. It has increased about 3 times compared to before.
However, in the above example, it was heated at 230°C.
This can be sufficiently processed at a temperature of about 200 to 350°C.

A very large electromagnet is required to subject a sample of the same length to magnetic field heat treatment using conventional methods.

By applying the present invention, an amorphous metal tape can be continuously heat-treated in a magnetic field.

An example is shown in FIG. Symbol 7 is a copper roll through which a large current flows. A magnetic field is applied by supplying the sample 8 to a roll and winding it around the roll. If these are placed in a heating device, heat treatment in a magnetic field can be performed. The heat treatment time can be controlled by appropriately selecting the roll rotation speed and winding width. Such a method can be easily carried out because the amorphous metal is thin and relatively soft. In this example, it was produced by the single roll method (COO.,
4FeO. Although the example of O6)82B,8 amorphous alloy has been described, it goes without saying that the present invention is applicable to all materials obtained by other common methods for producing amorphous metals.

However, since the saturation magnetic field differs depending on the material, the current value to be passed through the conductor wire must be selected appropriately. Furthermore, the optimum heat treatment temperature and time also vary depending on the material. For the materials of this embodiment, the heat treatment can be carried out in air, but for Fe-rich alloys etc. that are easily oxidized, it is necessary to use an inert gas atmosphere or a vacuum. These techniques are conventionally known. Furthermore, CU, At, etc. can be used as the conducting wire, and if a heating element such as a suitable alloy is used, it can also serve as a heating device.

However, the surface of the conductor should be insulated as necessary. Depending on the material, instead of a magnetic field, or at the same time as a magnetic field, by applying an appropriate tension? It is also known that magnetic properties can be further improved. In the method according to the invention as shown in FIG. 5, it is also easy to change the tension at the same time.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a conventional magnetic field heat treatment method, FIG. 2 is a diagram showing a magnetic field heat treatment method of the present invention, FIGS. 3 and 4 are diagrams for explaining the effects of the present invention, and FIG. The figure is a diagram showing a heat treatment method in a magnetic field to which the present invention is applied.

Claims (1)

[Claims] 1. An amorphous metal body is wrapped around a conductor, and a magnetic field is applied to the amorphous metal body by passing a current through the conductor, and heat treatment is performed in the magnetic field by heating the amorphous metal body in a magnetic field. Heat treatment method.