JP2006097103A - Method for producing magnetostriction material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetostriction material by a sintered compact having high density and also having high magnetostriction value. <P>SOLUTION: The method for producing a magnetostriction material is provided with: a stage where a molding comprising a raw material A having a composition expressed by formula (1): (Tb<SB>x</SB>Dy<SB>1-x</SB>)T<SB>y</SB>(T is at least one kind of metallic element selected from the group consisting of Fe, Ni and Co, and x and y lie in the ranges of 0.35<x≤0.5 and 1.7≤y≤2.0), a raw material B having a composition expressed by formula (2): Dy<SB>t</SB>T<SB>1-t</SB>(t lies in the range of 0.9≤t≤1.0), and a T-containing raw material C: ≥7 wt% is obtained; and a stage where the molding is sintered, so as to obtain a sintered compact expressed by formula (3): (Tb<SB>v</SB>Dy<SB>1-v</SB>)T<SB>w</SB>(v and w lie in the ranges of 0.27≤v<0.5 and 1.7≤w≤2.0). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a magnetostrictive material whose length changes when an external magnetic field is applied, and particularly to a technique for improving a magnetostriction value by adjusting a raw material powder when obtaining a magnetostrictive material by sintering. .

A phenomenon in which the size of a magnetic material changes when a ferromagnetic material is magnetized is called magnetostriction, and a material in which such a phenomenon occurs is called a magnetostrictive material. The saturation magnetostriction constant, which is the amount of saturation change due to magnetostriction, generally has a value of 10 ⁻⁵ to 10 ⁻⁶ , and a magnetostrictive material having a large saturation magnetostriction constant is also called a super magnetostrictive material, such as a vibrator, filter, sensor, etc. Widely used. At present, a magnetostrictive material mainly composed of an RFe ₂ Laves type intermetallic compound which is a compound of R (rare earth element) and Fe is known as a material having a large saturation magnetostriction constant (for example, US Pat. No. 3,949,351 (Patent Document). 1), 4152178 (patent document 2), 4308474 (patent document 3), and 4375372 (patent document 4)). However, these materials have a problem that the magnetostriction value is large when the applied external magnetic field is large, but the magnetostriction value is not sufficient when the external magnetic field is small. Therefore, in a magnetostrictive material having an RFe ₂ Laves-type intermetallic compound as a main phase, studies have been made to increase the magnetostriction value even in a low external magnetic field, and the orientation is in the [111] axis direction with an easy magnetization axis and a large magnetostriction constant. It has been proposed to let In addition, as a material mainly composed of RFe ₂ Laves type intermetallic compound, this composition was exclusively adopted because it has a large magnetostriction value when it has a composition of Tb _0.3 Dy _0.7 Fe _2.0 (atomic ratio).

In order to obtain a high orientation by shaping in a magnetic field, the formula I (Tb _x Dy _1-x ) T _y (wherein T is at least one element selected from Fe, Co and Ni, x And y represents an atomic ratio, and the powder of the raw material A having a composition represented by 0.30 <x ≦ 0.50 and 1.70 ≦ y ≦ 2.00, and a formula II (Dy _1-t Tb _t ) _z T _1-z (in the formula II, t and z represent an atomic ratio, 0 ≦ t ≦ 0.30, 0.40 ≦ z ≦ 0.80) A mixture containing a raw material A or a raw material C substantially composed of T in addition to the raw material A and the raw material B is molded in a magnetic field and then sintered to obtain a compound of formula III (Tb _v Dy _{1− v} ) T _w (in formula III, v and w represent atomic ratios, 0.27 ≦ v <0.50, 1.70 ≦ w ≦ 2.00) Japanese Patent Laid-Open No. 7-286249 (Patent Document 5) proposes a method of manufacturing a magnetostrictive material having a composition represented by Patent Document 5 uses the above-mentioned raw material A that has crystal magnetic anisotropy that allows the easy magnetization axis to be sufficiently oriented by molding in a magnetic field, and whose easy magnetization axis is the [111] axis. However, since the sintered body of the raw material A has too large magnetocrystalline anisotropy, the magnetic field response when used as a magnetostrictive material is poor and is not practical. Therefore, in Patent Document 5, a material obtained by adding the raw material A, the raw material B, and the raw material C is molded in a magnetic field and sintered. Since element diffusion occurs during sintering, a polycrystalline magnetostrictive material having a composition near Tb _0.3 Dy _0.7 Fe _2.0 is obtained. This polycrystalline magnetostrictive material has a large magnetostriction because the [111] axis orientation of the raw material A is maintained, and has a suitable magnetocrystalline anisotropy as a magnetostrictive material, and therefore a good magnetic field response is obtained. However, the method of manufacturing a magnetostrictive material proposed in Patent Document 5 has a problem that the sintered density is not always sufficient.

As a method for solving this problem, a method of performing hydrogen storage treatment on the raw material B has been proposed in Japanese Patent Application Laid-Open No. 2002-129274 (Patent Document 6).
According to Patent Document 6, by causing hydrogen to be stored in the raw material B, distortion occurs due to formation of a hydride or hydrogen atoms invading the crystal, and the raw material B cannot withstand the internal stress. Cracks occur. The pressure applied when the raw material A and the raw material C are mixed and molded in a magnetic field acts as a stress concentration on the tip of the crack, and the crack further progresses. Therefore, it is disclosed that the raw material B is pulverized and refined inside the mixed state and enters between the raw materials A to obtain a dense and high-density sintered body.
Furthermore, as a method for improving the sintering density, a proposal for sintering in a mixed atmosphere of hydrogen gas and inert gas is disclosed in Japanese Patent Laid-Open No. 2003-3203 (Patent Document 7).

U.S. Pat. No. 3,949,351 U.S. Pat. No. 4,152,178 U.S. Pat. No. 4,308,474 U.S. Pat. No. 4,375,372 JP-A-7-286249 JP 2002-129274 A JP 2003-3203 A

  As described above, various methods for increasing the density of the magnetostrictive material by sintering have been studied. However, Patent Documents 5 to 7 are still insufficient to obtain a function as a magnetostrictive material, that is, a large magnetostriction value. . The present invention has been made based on such a technical problem, and an object thereof is to provide a magnetostrictive material having a further improved magnetostriction value.

  The present inventors improve the magnetostriction value of the obtained magnetostrictive material on the premise of a method for producing a magnetostrictive material using a mixture of three kinds of raw materials (A to C) disclosed in Patent Documents 5 to 7. It was investigated. In particular, in molding in a magnetic field, it was studied to obtain a high magnetostriction value by improving the degree of orientation of the raw material A that is responsible for forming the main phase of the magnetostrictive material. In order to improve the orientation degree of the raw material A, the strength of the magnetic field applied to the compact during molding in the magnetic field may be increased. For that purpose, the soft body should contain more soft magnetic components. This is because the amount of magnetic flux passing through the molded body increases.

Here, the raw material C constitutes a soft magnetic component in the molded body. Therefore, if the amount of the raw material C contained in the molded body is increased, the degree of orientation by molding in a magnetic field may be improved. Then, when this inventor investigated the relationship between the quantity of the raw material C and a magnetostriction value, it discovered that increasing the quantity of the raw material C can improve a magnetostriction value.
Here, if the amount of the raw material C composed of the element T is simply increased, the amount of the element T in the raw material A, the raw material B, and the raw material C becomes excessive. Therefore, it is necessary to reduce the amount of the element T contained in the raw material A and / or the raw material B according to the increase of the raw material C. However, the raw material A is for forming the main phase, and changing its composition is not desirable for the magnetostriction value. Therefore, the present invention has been made to cope with an increase in the amount of the raw material C by reducing the amount of the element T contained in the raw material B.

The present invention based on the above is the formula (1): (Tb _x Dy _1-x ) T _y (T is at least one metal element selected from the group of Fe, Ni, Co, and x, y are A raw material A having a composition represented by 0.35 <x ≦ 0.5, 1.7 ≦ y ≦ 2.0), and formula (2): Dy _t T _1-t (t is 0.9 ≦ t ≦ 1.0), a step of obtaining a molded body containing a raw material B having a composition represented by T and a raw material C containing T: 7 wt% or more, and sintering the molded body to formula (3): Sinter represented by (Tb _v Dy _1-v ) T _w (v and w are in the range of 0.27 ≦ v <0.5, 1.7 ≦ w ≦ 2.0) A method for producing a magnetostrictive material, comprising: a step of obtaining a body.

In the method for producing a magnetostrictive material of the present invention, the amount of the raw material C contained in the molded body may be 7.5 wt% or more by setting the raw material B to Dy alone, that is, t = 1 in the formula (2). And can further contribute to the improvement of the magnetostriction value.
In the method for producing a magnetostrictive material of the present invention, it is preferable that the raw material B has been subjected to hydrogen storage treatment. This is because it is effective for improving the sintered density.

  As described above, according to the present invention, the effect of improving the magnetostriction value by increasing the amount of the element T contained in the molded body in addition to the effect of improving the magnetostriction value by using the mixture of three kinds of raw materials (A to C). In addition, a magnetostrictive material having a particularly high magnetostriction value can be obtained. In addition, by subjecting the raw material B to hydrogen storage treatment, it is possible to obtain a magnetostrictive material having such a high magnetostriction value and a high-density sintered body.

FIG. 1 is a flowchart showing a method for producing a magnetostrictive material according to an embodiment of the present invention. The present invention will be described below with reference to this flowchart.
The method for producing a magnetostrictive material of the present invention uses a raw material A represented by the formula (1): (Tb _x Dy _1-x ) T _y . Here, T of the raw material A is at least one metal selected from the group of Fe, Co, and Ni. In particular, the element T may be Fe alone. This is because Fe forms a Tb, Dy and (Tb, Dy) Fe ₂ intermetallic compound having high magnetostriction characteristics. At this time, a part of Fe may be substituted with Co and Ni. However, Co increases magnetic anisotropy but decreases magnetic permeability, and Ni lowers the Curie temperature. In order to reduce the magnetostriction value at room temperature and high magnetic field, Fe is 70 wt% or more, more preferably 80 wt% or more.

  In addition, the raw material A may contain a transition metal that forms an alloy with rare earth metals such as Tb and Dy. Specific examples of the transition metal include Mn, Cr, Mo, and W. A part of Tb of the raw material A may be substituted with rare earth (R ′) excluding Dy. Examples of R ′ include Nd, Pr, Gd, and Y.

In the formula (1), x and y are in the range of 0.35 <x ≦ 0.5 and 1.7 ≦ y ≦ 2.0. When x is a small value of 0.35 or less, orientation in the [111] axial direction becomes difficult, and when x exceeds 0.5, the ratio of the raw material A to the entire magnetostrictive material decreases, so that after sintering, [111] The degree of orientation in the axial direction is lowered. If y is less than 1.7, the ratio of the raw material A to the entire magnetostrictive material becomes small, and the degree of orientation in the [111] axial direction after sintering becomes low. When y is large, there are many Fe-rich phases such as (Tb, Dy) T _3. For this reason, the degree of orientation due to molding in a magnetic field is lowered, and accordingly the degree of orientation of the magnetostrictive material after sintering is also lowered. Therefore, y is set to 2.0.
Preferred x is 0.3 ≦ x ≦ 0.45, and more preferred x is 0.34 ≦ x ≦ 0.40. Further, preferable y is 1.8 ≦ y ≦ 2.0, and more preferable y is 1.87 ≦ x ≦ 1.92.

In the method for producing a magnetostrictive material of the present invention, the raw material B may contain formula (2): Dy _t T _1-t (Dy may include both or either of Tb and Ho, and t is 0.9. ≦ t ≦ 1.0) is used. If t is less than 0.9, the amount of the raw material C contained in the molded body cannot be increased, and the effect of the present invention, that is, the degree of orientation improvement in molding in a magnetic field cannot be fully enjoyed. Preferred t is 0.95 or more, and most preferred is t = 1.

  Moreover, it is preferable that the raw material B contains hydrogen of 7000 ppm <= hydrogen amount <= 22000 ppm by performing a hydrogen storage process. The raw material B becomes brittle by occlusion of hydrogen, and this is mixed with the raw material A and the raw material C, and is pulverized and refined inside the mixed state by the pressure at the time of forming a molded body. Therefore, it becomes easy to enter between the raw materials A that are responsible for forming the main phase, and when sintered, a dense and dense sintered body is formed.

  The amount of hydrogen stored in the raw material B is preferably in the range of 7000 ppm ≦ hydrogen amount ≦ 22000 ppm. When the amount of hydrogen is less than 7000 ppm, the amount of hydrogen is small, the internal strain of the raw material B is small, cracks during molding are small, the density is low, and the open pores are also large. In addition, the magnetostriction characteristics deteriorate due to long-term use. Moreover, when the amount of hydrogen exceeds 22000 ppm, the refinement | miniaturization of the raw material B will be saturated and there will be no effect of occlusion any more.

  The method for producing a magnetostrictive material of the present invention uses a raw material C containing T. As described above, T is at least one metal selected from the group consisting of Fe, Co, and Ni, and among these, Fe is most preferable. In the present invention, 7 wt% or more of the raw material C is added. Thus, a high magnetostriction value can be obtained by adding 7 wt% or more of the raw material C. It is preferable that the amount of the raw material C in the molded body is 7.5 wt% or more, further 8 wt% or more by setting t of the raw material B to a high value.

The method for producing a magnetostrictive material of the present invention comprises mixing the raw material A, the raw material B, and the raw material C described above, molding in a magnetic field, and sintering, and expressed by the formula (3): (Tb _v Dy _1-v ) T _w To produce a magnetostrictive material. Here, v and w are in the range of 0.27 ≦ v <0.5, 1.7 ≦ w ≦ 2.0. When v is less than 0.27, a sufficient magnetostriction value is not shown in a temperature range lower than room temperature, and when v is 0.5 or more, a sufficient magnetostriction value is not shown in a room temperature range. When w is less than 1.7, there are many rare earth-rich phases, and when w exceeds 2.0, a different phase such as a (Tb, Dy) T ₃ phase is generated and the magnetostriction value is lowered.
Preferred v is 0.27 ≦ v ≦ 0.40, and more preferred v is 0.27 ≦ v ≦ 0.34. Further, preferable w is 1.8 ≦ w ≦ 1.95, and more preferable w is 1.87 ≦ w ≦ 1.92.

The mixing ratio of the raw material A, the raw material B, and the raw material C can be appropriately determined so as to be a magnetostrictive material represented by the formula (3), but it is preferable to follow the following.
When the weight percentage of the raw material A is a, the weight percentage of the raw material B is b, and the weight percentage of the raw material C is c, the raw material A is preferably 50 ≦ a <100, more preferably 60 ≦ a ≦ 95. When a is too small, that is, when the ratio of the raw material A that is oriented in molding in a magnetic field is low, the degree of orientation of crystals after sintering becomes low. On the other hand, when a is too large, it means that the composition of the raw material A is close to the final composition, and the meaning of using the raw material A for facilitating magnetic field orientation is lost.
The raw material B is preferably 0 <b ≦ 40, more preferably 5 ≦ b ≦ 30. Since the raw material B acts as a flux during sintering, if b is too small, sintering is difficult to proceed and it is difficult to obtain a dense magnetostrictive material. On the other hand, if b is too large, a becomes too small, causing the above-mentioned adverse effects.
As described above, the raw material C preferably has c ≦ 7.5, more preferably c ≦ 8. Note that a + b + c = 100.

The above raw materials A, B, and C constitute a magnetostrictive material made of a sintered body through the respective steps shown in FIG.
As the raw material A, Tb, Dy, and Fe are weighed so as to correspond to the above formula (1) and melted in an inert atmosphere of, for example, Ar gas to produce an alloy. This alloy can be annealed at a temperature of about 1150 to 1230 ° C. to make the concentration distribution of each metal element uniform during the production of the alloy and to eliminate the precipitated heterogeneous phase. Next, the raw material A is pulverized to an average particle size of about 5 to 20 μm.

  As the raw material B, Dy or an alloy made of Dy and T is prepared and pulverized in the same manner as the raw material A. Next, the pulverized raw material B is held in a hydrogen atmosphere or a mixed atmosphere of hydrogen and an inert gas, and a hydrogen occlusion treatment is performed by allowing hydrogen atoms to enter the crystal lattice of the raw material B or using a hydride. As described above, the amount of hydrogen contained in the raw material B is preferably 7000 to 22000 ppm. The raw material B is cracked by the hydrogen storage treatment. When the raw material B is comprised from the alloy which consists of Dy and T, it refines | pulverizes to about 5-200 micrometers by a crack. When the raw material B is composed of Dy alone, it is difficult to pulverize like an alloy composed of Dy and T due to cracks after the hydrogen storage treatment. This pulverization may be performed with an average particle diameter of about 1 to 10 μm. The temperature at which the hydrogen storage treatment is performed is 100 to 200 ° C. when the raw material B is composed of an alloy composed of Dy and T, and 250 to 450 ° C. when the raw material B is composed of Dy alone. At this temperature, the raw material B can contain the above amount of hydrogen if the holding time is 1 to 20 hours. The hydrogen content depending on the holding time also depends on the size of the raw material B alloy.

  By subjecting the raw material B to hydrogen storage treatment, the oxidation resistance of the raw material B can be improved. Since Dy, which is a rare earth element, is easily oxidized, an oxide film having a high melting point is formed on the surface even with a slight amount of oxygen. This oxide film suppresses the progress of sintering. Therefore, the density of the obtained sintered body is low and the number of open pores is also increased. When the number of open pores increases, the oxidation of Dy further proceeds during long-term use, and the magnetostrictive characteristics are lowered accordingly. Therefore, a high sintered density can be obtained by subjecting the raw material B to hydrogen storage treatment to produce a sintered body, and deterioration of the magnetostrictive characteristics over time can be suppressed.

  The raw material C is preferably crushed in the same manner as the raw material A and the raw material B and then subjected to a reduction treatment for removing oxygen adhering to the surface. For example, the reduction treatment may be held in a hydrogen atmosphere at 300 to 600 ° C. for about 1 to 3 hours.

  The raw material A, the raw material B, and the raw material C obtained as described above are weighed and mixed so as to finally have a desired composition, and then pulverized. In the pulverization treatment, a pulverizer such as a wet ball mill, an attritor or an atomizer can be appropriately selected. In particular, an atomizer is preferable. This is because impact and shear can be applied at the same time, powder aggregation is prevented, and productivity is high. The average particle size after pulverization is 1 to 100 μm, preferably 5 to 20 μm. If the particle size is too small, oxidation tends to proceed during the manufacturing process, and the magnetostrictive properties are deteriorated. If the average particle size is too large, the sintering is difficult to proceed, the sintering density is not increased, and the open pores are increased.

The mixed raw material A, raw material B, and raw material C are formed into a desired shape before sintering. By performing this molding in a magnetic field, the raw material A is mainly aligned in a certain direction, and the sintered magnetostrictive material is oriented in the [111] axial direction. The applied magnetic field is 2.4 × 10 ⁴ A / m or more, preferably 4.8 × 10 ⁴ A / m or more. The direction of the magnetic field may be perpendicular or parallel to the direction of pressure. The molding pressure is 4.9 × 10 ⁴ Pa or more, preferably 2.9 × 10 ⁵ Pa or more.

  Since the molded body contains 7 wt% or more of the raw material C as compared with the prior art, the amount of magnetic flux passing through the molded body during molding in a magnetic field increases. Therefore, the orientation degree of the raw material A becomes high, and as a result, the orientation degree in the [111] axial direction in the sintered magnetostrictive material can be increased. Therefore, it is understood that the magnetostriction value of the magnetostrictive material according to the present invention is increased.

  The molded body obtained by molding in a magnetic field is sintered. Sintering conditions are 1100 degreeC or more, Preferably it is 1150-1250 degreeC and it is good to carry out for 1 to 10 hours. The sintering atmosphere is preferably a non-oxidizing atmosphere, and is preferably an inert gas such as Ar gas or in a vacuum.

The magnetostrictive material manufactured in this way has the formula (3): (Tb _v Dy _1-v ) T _w (where v and w are 0.27 ≦ v <0.5 and 1.7 ≦ w). ≦ 2.0.) And is oriented in the [111] axis direction where magnetostriction is greatest. The average grain size of crystal grains of the magnetostrictive material is 10 μm or more. If the average grain size of the crystal grains is small, the grain boundaries increase and the magnetic susceptibility due to the external magnetic field decreases. The upper limit of the average grain size of the crystal grains is not particularly limited, but when the thickness is 200 μm or more, the magnetostriction value is almost saturated and does not need to be increased any more.

As the raw material A, Tb, Dy, and Fe were weighed so as to have a composition of Tb _0.4 Dy _0.6 Fe _1.93 and dissolved in an Ar gas atmosphere to prepare a raw material alloy. This alloy was annealed at 1170 ° C. for 20 hours to make the concentration distribution of each metal element uniform during the preparation of the alloy, and the precipitated heterogeneous phase disappeared. Next, this raw material alloy is pulverized (coarsely pulverized) with a brown mill. After coarse pulverization, coarse particles of 2 mm or more were removed with a mesh. The average particle size of the powder after removal of coarse particles is 500 μm. In addition, an average particle diameter is the value measured with the subsieve sizer measuring apparatus (made by a Fischer company).

Next, as shown below, four types of raw materials B were produced.
Dy, Fe and Co were weighed so as to have compositions of Dy _1.5 Fe, Dy ₂ Fe and Dy ₁₂ Fe and dissolved in an Ar gas atmosphere to produce a raw material alloy. Similarly, metal Dy was pulverized with a brown mill. Next, for Dy _1.5 Fe, Dy ₂ Fe, and Dy ₁₂ Fe, a hydrogen storage treatment is performed in a hydrogen gas atmosphere at 150 ° C. for 1 hour, and for metal Dy, a hydrogen gas atmosphere is maintained at 350 ° C. for 10 hours. Hydrogen storage treatment was performed. The metal Dy was pulverized in an Ar gas atmosphere using an atomizer (manufactured by Tokyo Atomizer Manufacturing Co., Ltd.) after hydrogen storage treatment to obtain a powder having an average particle size of 15 μm. Further, Dy _1.5 Fe, Dy ₂ Fe and Dy ₁₂ Fe were pulverized with hydrogen to an average particle size of about 15 μm after the hydrogen storage treatment. In addition, the hydrogen content of each raw material B was in the range of 17000 to 22000 ppm. The amount of hydrogen is a value measured by a hydrogen amount measuring device (manufactured by HORIBA: ZWGA-G21).

As the raw material C, Fe powder having an average particle diameter of 8 μm subjected to reduction treatment for removing oxygen in a hydrogen gas atmosphere at 300 ° C. for 1 hour was used. The oxygen content of the raw material C is about 2000 ppm.
The above raw material A, raw material B and raw material C were weighed and mixed so as to have a final composition of Tb _0.34 Dy _0.66 Fe _1.875 .

Subsequently, it was pulverized in an Ar gas atmosphere using an atomizer (manufactured by Tokyo Atomizer Manufacturing Co., Ltd.) to obtain a finely pulverized powder having an average particle size of 9 μm. Next, the finely pulverized powder was molded in a magnetic field at a pressure of 8 ton / cm ^{2 in} a magnetic field of 12 kOe. The forming was transverse magnetic field forming in which the magnetic field was applied in the direction perpendicular to the pressing direction. The obtained molded body was sintered in an Ar gas atmosphere at 1225 ° C. for 3 hours. The density of the sintered body was measured. Further, the sintered body was processed to prepare test pieces of φ3.5 × 30 (mm) and φ12 × 20 (mm), and the magnetostriction value was measured. The above measurement results are shown in Table 1. FIG. 2 shows the relationship between the amount of raw material C (Fe) and the magnetostriction value. It can be seen from Table 1 and FIG. 2 that the magnetostriction value increases as the amount of the raw material C, that is, Fe increases.

It is a flowchart which shows the process of the manufacturing method of the magnetostrictive material in this Embodiment. It is a graph which shows the relationship between the quantity of raw material C (Fe), and a magnetostriction value.

Claims (3)

Formula (1): (Tb _x Dy _1-x ) T _y (T is at least one metal element selected from the group of Fe, Ni and Co, and x and y are 0.35 <x ≦ 0. 0.5, 1.7 ≦ y ≦ 2.0), a raw material A having a composition represented by:
A raw material B having a composition represented by the formula (2): Dy _t T _1-t (t is a range of 0.9 ≦ t ≦ 1.0);
A step of obtaining a molded body containing a raw material C containing T: 7 wt% or more;
The molded body is sintered to obtain a formula (3): (Tb _v Dy _1-v ) T _w (v and w are in the range of 0.27 ≦ v <0.5 and 1.7 ≦ w ≦ 2.0). A step of obtaining a sintered body represented by:
A method for producing a magnetostrictive material, comprising:   2. The method of producing a magnetostrictive material according to claim 1, wherein in the formula (2), t = 1, and the amount of the raw material C contained in the compact is 7.5 wt% or more.   The method for producing a magnetostrictive material according to claim 1, wherein the raw material B has been subjected to hydrogen storage treatment.

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