KR0120280B1 - Making method of rare-earth-ferro magnetic transformation alloys and the same product - Google Patents

Abstract

Process for preparing rare earth-iron magnetostriction alloy is claimed. Thus, mother metal consists of 25-30 atom% of Dy, 56-70 atom% of Fe, and 0-15 atom% of B is melted in a quarth furnace which is under the pressure of 1.5x101-2.0x10-1 MPa at 1,200-1,400 deg.C in an inactive atmophere and cooled rapidly at a speed of 1x105-1x107 K/sec by injecting molten metal on a cooling roll which is rolling at a linear velocity of 10-50 m/sec.

Description

Rare earth-iron magnetostrictive alloy and its manufacturing method

1 is a graph showing a change in magnetostriction value according to the applied magnetic field of the alloy of the present invention.

2 is an enlarged photo of the microstructure of the alloy of the present invention.

3 is a limited-field diffraction pattern photograph of the alloy of the present invention.

4 to 7 are graphs showing the change of the magnetostriction value according to the applied magnetic field of the alloy of the present invention.

The present invention relates to a rare earth-iron magnetostrictive alloy, and in particular, a small amount of B added to a Dy-Fe alloy system is rapidly solidified from a molten state at an appropriate rate so that the crystal grains of the microstructure are uniformly distributed. The present invention relates to a rare earth-iron magnetostrictive alloy having improved deformation characteristics and a method of manufacturing the same.

In the early 1970s, R-TM-based intermetallic compounds were developed that exhibited large magnetostrictions at room temperature, where R is a rare earth element and TM is a transition metal, among which TbFe2 is a representative R-TM alloy. [Note: Physics Letters A, Vol, 37, P.413, 1971: Physical Review B, Vol. 5, P. 3642, 1972.

However, the saturation magnetostriction of TbFe ₂ alloy is very large at about 1750 × 10 ^-6 (or 1750ppm) at room temperature, but this alloy has very high crystal magnetic anisotropy. I have it.

In the practical application of magnetostrictive materials, it is important to obtain large magnetostrictions at low magnetic fields. Therefore, many studies on magnetostrictive materials have been conducted in this direction.

In other words, research related to the development of new magnetostrictive materials is focused on improving the magnetostrictive properties by reducing the crystal anisotropy (ie, improving the soft magnetic properties). The following two methods have been mainly used.

One of the methods, which was studied in the early stages, is to reduce the magnetic anisotropy by changing the composition and composition of the alloy (ie, alloy design). The most representative example of such a method is to remove part of Tb from TbFe ₂ alloy. there may be mentioned in which pseudo binary (R _1, R ₂₎ -TM alloy is substituted by other rare earth elements. And the magnetostrictive material developed as a result of these studies, Tb ₀ . ₃ DY _0.7 Fe ₂ is known.

On the other hand, in recent years, studies are being actively conducted to improve the soft magnetic properties by miniaturizing or amorphousening the grain size of the R-TM alloy.

The background of this study is that the intrinsic magnetic anisotropy does not change when the grain is refined, but the effective magnetic anisotropy decreases, and the amorphous magnetic anisotropy is lost when the crystallization is amorphous.

However, in such materials, the saturation magnetic strain generally tends to decrease. In particular, the amorphous magnetization rapidly decreases the saturation magnetic strain.

In addition, recently, it has been reported that the soft magnetic properties of the Tb-Fe-B alloy containing B were rapidly solidified to an amorphous phase and then subjected to an appropriate heat treatment to precipitate a TbFe ₂ phase having a size of about 10 nm. [Reference: Japanese Society of Applied Magnetics, Vol, 17, P.271, 1993].

However, Tb-Fe-based alloys, which have been introduced so far, have a critical disadvantage in terms of economics despite having excellent magnetostrictive properties because of the high price of Tb elements.

Therefore, one way to overcome the above disadvantages of the Tb-Fe-based alloy may consider a Dy-Fe-based alloy in which Tb is replaced with Dy.

Dy is adjacent to Tb on the periodic table, so its physical properties are similar to Tb, but at a much lower price.

Although DyFe ₂ has a high saturation magnetostriction but also has very large crystal anisotropy, it does not saturate even in a magnetic field of several tens of kOe. On the contrary, this may mean that if the microstructure is properly controlled in DyFe ₂ , there is a possibility that the soft magnetic properties may be improved to provide room for greatly improving the magnetostrictive properties.

Accordingly, the present inventors have shown excellent properties when the magnetostrictive properties were tested with the sample obtained by adding the appropriate amount of B to the Dy-Fe alloy and rapidly solidifying by controlling the cooling rate in consideration of the above matters. Came to uncover.

That is, in the present invention, the Dy-Fe-B ternary alloy in which a small amount of B is added to the Dy-Fe alloy is used as a mother alloy to dissolve it and then rapidly cooled at an appropriate cooling rate so that fine grains can be made fine. An object of the present invention is to provide a rare earth-iron magnetostrictive alloy and a method of manufacturing the same.

The composition of the alloy of the present invention is as follows.

DyxFe _y B _Z

Where x, y, z is atomic%

25≤x≤30

56≤y≤70

0≤z≤15

(Where x + y + z = 100)

Such a method for producing a magnetostrictive alloy of the present invention by mixing and dissolving the raw material components in the composition range to obtain a master alloy and then spraying the molten metal toward a single-roll type liquid quenching apparatus that rotates at a constant speed under an active gas atmosphere. By a process for producing a thin magnetized magnetostrictive alloy.

The alloy obtained by the method of the present invention has a microstructure in which 10 nm sized grains are uniformly distributed, and exhibits large magnetostriction characteristics even in a low magnetic field.

The magnetostriction characteristics and specific manufacturing process of the alloy of the present invention will be clearly understood through the following examples.

Example 1

The master alloy consisting of 30 atomic% Dy, 56 atomic% Fe and 14 atomic% B was dissolved by vacuum arc melting. This alloy was placed in a quartz tube about 0.5 mm in diameter of the nozzle, and a thin sample was prepared using a single-roll liquid quenching apparatus capable of maintaining vacuum and inert atmosphere. During dissolution of the alloy and injection of the molten metal, the chamber of the quenching device was prevented from oxidizing the sample sample with an inert gas (eg, argon) at a pressure of 2 × 10 ⁻² MPa. When the molten metal reached the appropriate temperature, the molten metal was sprayed through a nozzle onto a copper cooling roll rotating at a linear speed of 10, 20, 30, 40, 50 m / s by applying an inert gas at a pressure of 1.85 × 10 ⁻¹ MPa. .

The magnetostriction value (λ) was measured by the three-terminal capacitive method for the quenched solidified ribbon thus obtained. Measurements were made at room temperature and magnetic fields up to 8 kOe were applied. The results of the magnitude of the magnetostriction with the applied magnetic field are shown in FIG.

The microstructure of the sample obtained in this example was composed of DyFe ₂ phase by X-ray diffraction and transmission electron microscopy, and the grain size was very fine as about 10 nm, and the grain size distribution was very uniform. The microstructure observed by the transmission electron microscope is shown in FIG. 2, and the results of the selected area diffraction of the transmission electron microscope are shown in FIG.

Example 2

A quench solidified ribbon was prepared in the same manner as in Example 1, except that a mother alloy composed of 30 atomic% Dy, 63 atomic% Fe, and 7 atomic% B was used. In this way, the magnetic strain was measured in the same manner as in Example 1, the results are shown in FIG.

Example 3

A quench solidified ribbon was prepared in the same manner as in Example 1, except that a mother alloy composed of Dy 30 atom% and Fe 70 atom% was used. In this way, the magnetic strain was measured in the same manner as in Example 1, the results are shown in FIG.

Example 4

A quench-coagulated thin ribbon was prepared in the same manner as in Example 1, except that a mother alloy composed of 25 atomic% Dy, 60 atomic% Fe, and 15 atomic% B was used. In this way, the magnetic strain was measured in the same manner as in Example 1, the results are shown in FIG.

Example 5

A quench-coagulated thin ribbon was prepared in the same manner as in Example 1 except that 25% by atom of Dy, 67.5% by atom of Fe and 7.5% by atom of B were used. In this way, the magnetic strain was measured in the same manner as in Example 1, the results are shown in FIG.

Comparative Example 1

For comparison with the measurement results for the alloy specimen of the present invention, the composition ratio between Dy and Fe is similar to the composition presented in the present invention, and the polycrystalline bulk sample consisting of 33.3 atomic% Dy and 66.7 atomic% Fe containing B is not included. The result of the change of magnetostriction with applied magnetic field with respect to [Ferromagnetic Materials, Vol. 1, North-Holland, Amsterdam, 1980, pp. 543] are shown in FIG.

In the above, the alloy of the composition proposed in the present invention was dissolved in an inert atmosphere using a liquid quenching apparatus and then rapidly solidified at an appropriate cooling rate to prepare a thin ribbon, thereby obtaining a material having excellent magnetostrictive characteristics. Is as follows.

The cooling rate at which a magnetostrictive material with good soft magnetic properties is obtained depends on the B content. When Dy is 30 atomic%, when the B content is low as 0 to 7 atomic%, a magnetostrictive material having excellent soft magnetic properties is obtained at a linear speed of the rotating cooling roll of 40 m / sec, and the B content is 14 In many cases, the magnetostrictive material having excellent soft magnetic properties is obtained at a linear speed of 20 to 30 m / sec. When Dy is 25 atomic%, when the B content is 4 to 11 atomic%, a magnetostrictive material having excellent soft magnetic properties is obtained at a linear cooling rate of 50 m / sec, and the B content is 15 atoms. In many cases, a magnetostrictive material having excellent soft magnetic properties is obtained at a linear cooling rate of 10 to 20 m / sec.

Particularly noteworthy in the present invention, even in the present invention, even if the ultrafine grain structure material in which 10 nm sized DyFe ₂ grains are uniformly distributed is obtained from rapid solidification without softening, the soft magnetic properties of the material having such a structure It shows very good magnetostrictive properties.

Claims (2)

Next formula DyxFe _y Bz Where x, y, z are atomic% 25≤x≤30 56≤y≤70 0≤z≤15 Rare earth-iron magnetostrictive alloy consisting of (x + y + z = 100). A master alloy consisting of Dy: 25 to 30 atomic%, Fe: 56 to 70 atomic% and B: 0 to 15 atomic% or less is dissolved in a quartz crucible placed in an inert atmosphere and maintained at a temperature range of 1200 to 1400 ° C; By the application of the molten metal containing the pressure of the inert gas, 1.5 × 10 ¹ to 2.0 × 10 ^-1 MPa into the quartz crucible, by spraying over the cooling roll for rotating the molten metal 10 to 50m / sec linear velocity of 1 × 10 ⁵ Preparing a rare earth-iron magnetostrictive alloy in the form of a thin ribbon having a grain size of 1 to 100 nm by quenching at a cooling rate of 1 × 10 ⁷ K / sec. Method for producing a rare earth-iron-based magnetostrictive alloy, characterized in that.