JP2005264279A - Hard magnetic composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hard magnetic composition by which a ThMn<SB>12</SB>phase can be easily formed even in the case where Nd is used as a rare earth element. <P>SOLUTION: The hard magnetic composition having high saturation magnetization (σs) and high anisotropic magnetic field (H<SB>A</SB>) can be obtained by providing a chemical composition which is represented by general formula R1<SB>1-x</SB>R2<SB>x</SB>(Mo<SB>y</SB>Fe<SB>100-y-w</SB>Co<SB>w</SB>)<SB>z</SB>Si<SB>u</SB>A<SB>v</SB>(wherein, R1 is one or more kinds from among rare-earth elements including Y, and Nd comprises ≥50% of R1; R2 is either or both of Zr and Hf; A is either or both of N and C; and, as to the mole ratio of the general formula, x≤0.18, y=5 to 12.3, z=11 to 12.8, u=0.1 to 2.3, v=0.5 to 3 and w=0 to 30 are satisfied) and in which [(mole ratio of Fe)+(mole ratio of Co)+(mole ratio of Mo)+(mole ratio of Si)]/[(mole ratio of R1)+(mole ratio of R2)]>12 is satisfied. Moreover, by using this hard magnetic composition, the ThMn<SB>12</SB>phase can be easily formed even in the case where Nd is used. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a hard magnetic composition suitable for use in a rare earth permanent magnet material used in a device such as a speaker or a motor that requires a magnetic field.

Among rare earth magnets, R-T-B rare earth permanent magnets are excellent in magnetic properties, and Nd as a main component is abundant in resources and relatively inexpensive. Therefore, various electric devices such as speakers and motors are used. Used for applications.
However, in recent years, the demand for miniaturization of electrical equipment has further increased, and development of new permanent magnet materials has been promoted. Among them, rare earth-iron-based magnet materials having a body-centered tetragonal or ThMn ₁₂ type crystal structure are disclosed in, for example, JP-A-63-273303, JP-A-5-65603, and JP-A-2000-114017. It has been reported.
JP-A-63-273303 discloses a formula RxTiyAzFeaCob (wherein R is a rare earth element including Y, A is one or more of each of B, C, Al, Si, P, Ga, Ge, Sn, S, and N). A rare earth permanent magnet having a weight percentage of x is 12 to 30%, y is 4 to 10%, z is 0.1 to 8%, a is 55 to 85%, and b is 34% or less). Disclosure. Japanese Patent Application Laid-Open No. 63-273303 describes that the A element enters between atoms and changes the distance between Fe in a preferable direction.

  JP-A-5-65603 discloses that R is Y, Th and a combination of two or more elements selected from the group consisting of all lanthanoid elements, and X is N (nitrogen) or B (boron). Alternatively, when C (carbon) or a combination of these elements is used, the atomic percentage includes R: 3 to 30%, X: 0.3 to 50%, the balance is substantially made of Fe, and the main phase is a body. An iron-rare earth permanent magnet material having a center tetragonal structure is disclosed. Japanese Patent Laid-Open No. 5-65603 discloses a part of Fe consisting of M elements (Ti, Cr, V, Zr, Nb, Al, Mo, Mn, Hf, Ta, W, Mg, Si, Sn, Ge, Ga). It is further proposed to include M: 0.5 to 30% in atomic percentage by substitution with one or a combination of two or more elements selected from the group. In Japanese Patent Application Laid-Open No. 5-65603, the M element is positioned as an element having a great effect in generating a body-centered tetragonal crystal structure.

JP 2000-1114017 discloses a general formula (R _1-u M _u ) (Fe _1-vw Co _v T _w ) _x A _y (where R, M, T, A are R: at least one element selected from rare earth elements including Y, M: at least one element selected from Ti, Nb, T: selected from Ni, Cu, Sn, V, Ta, Cr, Mo, W, Mn At least one element, A: at least one element selected from Si, Ge, Al, and Ga, and u, v, w, x, and y are 0.1 ≦ u ≦ 0.7 and 0 ≦ v, respectively. ≦ 0.8, 0 ≦ w ≦ 0.1, 5 ≦ x ≦ 12, 0.1 ≦ y ≦ 1.5), and the main hard magnetic phase has a ThMn ₁₂ type crystal structure. A permanent magnet material is disclosed. JP-A-2000-1114017 can reduce the amount of Si, Ge, etc., which are stabilizing elements of a phase having a ThMn ₁₂ type crystal structure (hereinafter referred to as ThMn ₁₂ phase) by substituting R element with M element. It is stated.

JP 63-273306 (Claims, page 3) Japanese Patent Laid-Open No. 5-65603 (Claims, page 4) JP 2000-1114017 A (claim, page 5)

While rare earth permanent magnets are required to have high characteristics, they are also required to be low in cost. Among the rare earth elements constituting the rare earth permanent magnet, Nd is less expensive than Sm, so it is desirable that Nd, which is less expensive than Sm, is the main element of the rare earth element. However, when Nd is used, it is difficult to produce a ThMn ₁₂ phase, and its production requires many nonmagnetic impurities and high-temperature, long-time heat treatment. In addition, sufficient characteristics could not be obtained because many nonmagnetic impurities were used. For example, in JP-A-5-65603 described above, annealing is performed at 900 ° C. for 7 days, and in JP-A 2000-1114017, only Sm is used as a rare earth element with some exceptions. ing.
Accordingly, an object of the present invention is to provide a hard magnetic composition capable of easily generating a ThMn ₁₂ phase even when Nd is used as a rare earth element and obtaining high magnetic properties.

The inventor of the present invention can easily generate a phase having a ThMn ₁₂ type crystal structure even when Nd is used as a rare earth element by adding predetermined amounts of Mo, Si and N at the same time. It has been found that sufficient characteristics can be obtained as a magnetic composition. In the general formula shown below, it was confirmed that saturation magnetization can be improved by substituting a part of Nd with Zr and / or Hf.

The present invention has been made on the basis of the above knowledge, and has a general formula: R1 _1-x R2 _x (Mo _y Fe _100- yw _Cow ) _z Si _{u Av} (where R1 is a rare earth containing Y) 1 type or 2 types or more of elements, and 50% or more thereof is Nd, R2 is 1 type or 2 types of Zr and Hf, A is 1 type or 2 types of N and C), The ratio is x = 0.18 or less, y = 5 to 12.3, z = 11 to 12.8, u = 0.1 to 2.3, v = 0.5 to 3, w = 0 to 30 And a hard magnetic composition characterized by satisfying (Fe molar ratio + Co molar ratio + Mo molar ratio + Si molar ratio) / (R1 molar ratio + R2 molar ratio)> 12.

The present invention can provide a hard magnetic composition substantially composed of a single-phase structure of a hard magnetic phase by setting the above composition range. In the present invention, this hard magnetic phase can have a ThMn ₁₂ type crystal structure.
In the present invention, even when 70% or more of R is Nd, a single-phase structure of a hard magnetic phase can be obtained, and this single-phase structure can be made into a phase having a ThMn ₁₂ type crystal structure. it can.
The amount (x) of the R2 element (one or two of Zr and Hf), which is a feature of the present invention, is preferably 0.04 to 0.06.

As described above, according to the present invention, a hard magnetic composition capable of easily generating a ThMn ₁₂ phase even when Nd is used as a rare earth element is provided. In particular, according to the present invention, even if Nd is 100%, a hard magnetic composition comprising a ThMn ₁₂ phase, in other words, a single phase structure of a hard magnetic phase can be obtained.

The reason for limitation of each element in this invention is demonstrated.
<R1 (rare earth element)>
R is an element essential for obtaining high magnetic anisotropy. In order to produce a ThMn ₁₂ phase as a hard magnetic phase, it is advantageous to use Sm. However, in the present invention, Nd accounts for 50 mol% or more of R1 in order to obtain cost merit. The present invention makes it possible to easily produce a ThMn ₁₂ phase while occupying 50 mol% or more of R1 with Nd. However, the present invention allows a rare earth element containing Y in addition to Nd. In that case, it is preferable to include one or more of Y, La, Ce, Pr, and Sm together with Nd. Among these, Pr exhibits a property substantially equivalent to Nd, and therefore, a value equivalent to Nd can be obtained also in characteristics, which is particularly preferable. According to the present invention, even when the ratio of Nd in R1 is as high as 70 mol% or more, or 90 mol% or more, a single-phase structure composed of a ThMn ₁₂ phase that is a hard magnetic phase can be obtained. As shown in the examples described later, according to the present invention, even when R1 is only Nd, that is, when Nd occupies 100% of R1, a single-phase structure composed of a ThMn ₁₂ phase that is a hard magnetic phase is obtained. be able to.

<R2 (Zr / Hf)>
The present invention includes one or two of Zr and Hf. This element is effective for improving magnetic properties, particularly saturation magnetization. R2 substitutes a part of R1 in the above general formula. When the R2 amount (x) exceeds 0.18, the saturation magnetization becomes lower than that without R2. Therefore, the R2 amount (x) is set to 0.18 or less (not including 0). A desirable R2 amount (x) is 0.01 to 0.15, and a more desirable R2 amount (x) is 0.04 to 0.06.

<Si>
Si is added to R1 (Nd) and Fe simultaneously with Mo, thereby contributing to stabilization of the ThMn ₁₂ phase as a hard magnetic phase. At this time, Si has an effect of entering between ThMn ₁₂ phase lattices and reducing the crystal lattice. When the Si amount (u) is less than 0.1, a phase having a Mn ₂ Th ₁₇ type crystal structure (hereinafter referred to as Mn ₂ Th ₁₇ phase) precipitates, and when it exceeds 2.3, α-Fe tends to precipitate. . Therefore, in the present invention, it is recommended that the Si amount (u) be in the range of 0.1 to 2.3. A desirable Si amount (u) is 0.1 to 2.0, and a more desirable Si amount (u) is 0.2 to 1.0. For Si, in relation to Fe, Co, Mo, R1, and R2, the molar ratio of Fe + the molar ratio of Co + the molar ratio of Mo + the molar ratio of Si / (the molar ratio of R1 + the molar ratio of R2)> 12 However, this point will be described later.

<Mo>
Mo contributes to the formation of a ThMn ₁₂ phase by substituting Fe. In order to sufficiently obtain this effect, the Mo amount (y) is set to 5 or more. Further, when the Mo amount (y) exceeds 12.3, the saturation magnetization is remarkably reduced. Therefore, in the present invention, the Mo amount (y) is set to 5 to 12.3. A desirable Mo amount (y) is 6 to 10, and a more desirable Mo amount (y) is 7 to 9.
Further, when the sum (z) of the Fe amount, Co amount and Mo amount is less than 11, both the saturation magnetization and the anisotropic magnetic field are low, and when it exceeds 12.8, α-Fe is precipitated. Therefore, in the present invention, the sum (z) of the Fe amount, the Co amount, and the Mo amount is set to 11 to 12.8. Desirable x is 11.5 to 12.5.

<A (one or two of N (nitrogen) and C (carbon))>
A is to expand the lattice of ThMn ₁₂ phase by entering the interstitial of ThMn ₁₂ phase is an element effective for improving the magnetic properties. However, if the amount of A (v) exceeds 3, precipitation of α-Fe is observed. On the other hand, if it is 0.5 or less, the effect of improving magnetic properties cannot be obtained sufficiently. Therefore, in the present invention, the A amount (v) is set to 0.5-3. A desirable A amount (v) is 0.5 to 2.7, and a more desirable A amount (v) is 1.0 to 2.5.

<Fe, Fe-Co>
The hard magnetic composition according to the present invention substantially contains Fe other than the above elements, but it is effective to substitute a part of Fe with Co. As will be described later in Examples, the saturation magnetization and the anisotropic magnetic field are increased by adding Co. The amount of Co is desirably added in a molar ratio of 30 or less, and more desirably in the range of 5 to 20. Note that the addition of Co is not essential.

<(Fe molar ratio + Co molar ratio + Mo molar ratio + Si molar ratio) / (R1 molar ratio + R2 molar ratio)>12>
The individual contents of Fe, Co, Mo, and Si are as described above. However, when the hard magnetic composition of the present invention has a ThMn _12- phase single phase structure, (Fe molar ratio + Co molar ratio + Mo It is important to satisfy the following condition: (Molar ratio of Si + Molar ratio of Si) / (R1 molar ratio + R2 molar ratio)> 12 As shown in the examples described later, the saturation magnetization and the anisotropic magnetic field are low when the above conditions are not satisfied.

The manufacturing method of the hard magnetic composition according to the present invention can be obtained by a known manufacturing method. In particular, for N which is an interstitial element, raw materials originally containing N can be used. However, after manufacturing a composition containing an element other than N, it is treated (nitrided) in a gas or liquid containing N. It is desirable to allow N to enter. N ₂ gas, N ₂ + H ₂ mixed gas, NH ₃ gas, or a mixed gas thereof can be used as a gas into which N can enter. The temperature of the nitriding treatment is 200 to 1000 ° C., desirably 350 to 700 ° C., and the nitriding treatment time may be appropriately selected within the range of 0.2 to 200 hours. The same applies to the treatment for invading C (carbonization treatment). A raw material originally containing C can be used, and after a composition containing an element other than C is produced, it is heated in a gas or liquid containing C. It can also be processed. Alternatively, C can be infiltrated by heat treatment with a solid containing C. Examples of the gas that can infiltrate C include CH ₄ , C ₂ H _{6, and the} like. Carbon black can be used as the solid containing C. Also in carbonization by these, conditions can be appropriately set within the same temperature and processing time range as nitriding.

Hereinafter, the present invention will be described in detail based on specific examples.
(First embodiment)
Using high-purity Nd, Zr, Fe, Mo, and Si metal as raw materials, Ar so that the alloy composition is Nd _1-x Zr _x (Mo _8.3 Fe _91.7 ) ₁₂ Si _1.0. A sample was prepared by an arc melting method in an atmosphere. Subsequently, this alloy was pulverized by a stamp mill and passed through a sieve having an opening of 38 μm, and then heat treatment (nitriding) was performed in a nitrogen atmosphere at a temperature of 430 to 520 ° C. for 100 hours. About each sample after heat processing, while performing the chemical composition analysis and the identification of the phase comprised, the saturation magnetization ((sigma) s) and the anisotropic magnetic field ( _HA ) were measured. The results are shown in Table 1.

In addition, identification of the phase comprised was performed based on the X ray diffraction method. X-ray diffraction was measured using a Cu tube at an output of 15 kW, and the presence or absence of peaks in the ThMn ₁₂ phase and the other phases was confirmed. Other phases include α-Fe, Mn ₂ Th ₁₇ phase and Nd nitride. To obtain high magnetic properties, it is desirable main diffraction lines other than ThMn ₁₂ phase is 50% or less of the peak intensity ratio with respect to the main diffraction lines ThMn ₁₂ phase. A specific example relating to the identification of the constituted phase will be described with reference to FIGS.

FIG. 1 is a chart showing X-ray diffraction measurement results of Example 3, Example 21, and Comparative Example 16, which will be described later. In Example 3 and Example 21, only a peak showing a ThMn ₁₂ phase was observed. On the other hand, in Comparative Example 16, the α-Fe peak can be confirmed. In Comparative Example 16, it is understood that since Th is contained excessively, the ThMn ₁₂ phase is decomposed and α-Fe is precipitated accordingly. This can be seen from Comparative Example 16 in which the peak of the ThMn ₁₂ phase decreases while the peak of α-Fe increases.
FIG. 2 is an enlarged view of the vicinity of the diffraction angle at which the α-Fe peak occurs. In the vicinity of this angle, the peak of ThMn ₁₂ phase and the peak of α-Fe are adjacent. In Example 3, only the peak of ThMn ₁₂ phase is observed. In Example 21, two peaks of ThMn ₁₂ phase and α-Fe are observed, but when the amount of α-Fe is small as described above, the influence on the characteristics is small. On the other hand, in Comparative Example 16, only the α-Fe peak is observed. Further, as can be seen from FIG. 1, the peak intensity ratio of the main diffraction line of α-Fe to the main diffraction line of ThMn ₁₂ phase seen in the vicinity of 42 ° is 50% or more. When a large amount of α-Fe is precipitated in this manner, the deterioration of characteristics becomes remarkable.

In addition, the saturation magnetization (σs) and the anisotropic magnetic field (H _A ) are the magnetization curve in the easy axis direction and the magnetization curve in the hard axis direction measured with a maximum applied magnetic field of 20 kOe using a VSM (vibrating magnetometer). Seeking based on. However, for convenience of measurement, the saturation magnetization (σs) is the maximum magnetization value on the magnetization curve in the easy axis direction. The anisotropic magnetic field (H _A ) was defined as the value of the magnetic field at which the tangent at 10 kOe on the magnetization curve in the hard axis direction intersects the value of saturation magnetization (σs).

As shown in Table 1, a saturation magnetization (σs) of 130 emu / g or more can be obtained by replacing part of Nd with Zr. The improvement effect of saturation magnetization (σs) due to Zr shows a peak when the Zr amount (x) is 0.05, and the saturation magnetization (σs) tends to decrease at an amount larger than that, and the Zr amount (x) is 0. .20, the saturation magnetization (σs) is lower than that without Zr. Further, when the Zr amount (x) is in the range of 0.02 to 0.15, a single phase structure of ThMn ₁₂ phase (hereinafter referred to as 1-12 phase) is obtained.
From the above, Zr amount (x) has the general _formula: in _{R1 1-x R2 x (Mo} y Fe 100-y-w Co w) z Si u T v is in the range of 0.01 to 0.18 Desirably, it is more desirable to set it as the range of 0.04-0.06.

(Second embodiment)
In the same manner as in the first example, a sample was prepared so as to have a composition of Nd _0.95 Zr _0.05 (Mo _8.3 Fe _91.7 ) ₁₂ Si _u N _1.5 , and the chemical composition was analyzed. The phase to be constructed was identified, and the saturation magnetization (σs) and the anisotropic magnetic field (H _A ) were measured. The results are shown in Table 2. The second example is an experiment conducted to confirm the influence of the Si amount (u) on the phase configuration, saturation magnetization (σs), and anisotropic magnetic field ( _HA ).

In Comparative Example 3 in which Si was not added, in addition to the 1-12 phase, there were an Mn ₂ Th ₁₇ phase (hereinafter referred to as 2-17 phase) and an α-Fe phase, and in particular, an anisotropic magnetic field ( _HA ) Is low. On the other hand, it turns out that Examples 8-11 which added Si become a single phase of 1-12 phase, and 1-12 phase is stabilized. The compositions of these 1-12-phase single phase, the saturation magnetization of more than 130 or 135emu / g (σs), it is possible to obtain more than 50 or 55kOe magnetic anisotropy field _{(H A).} However, in Comparative Example 4 in which the Si amount is 2.5, a large amount of α-Fe is precipitated and the characteristics are deteriorated. If α-Fe, which is soft magnetic, is present, that portion generates a reverse magnetic domain with a low magnetic field (demagnetizing field). Therefore, since the coercive force is lowered as a result of easily reversing the magnetic domain of the hard magnetic phase component, the presence of α-Fe is not desirable for rare earth permanent magnets that require a coercive force.
In the range of Examples 8 to 11, the anisotropic magnetic field ( _HA ) is higher as the Si amount is larger, and the saturation magnetization (σs) tends to be higher as the Si amount is smaller.

(Third embodiment)
In the same manner as in the first example, Nd _0.95 Zr _0.05 (Mo _8.3 Fe _91.7 ) _z Si _0.5 N _1.5 , Nd _0.95 Zr _0.05 (Mo _8.3 Fe _91.7 ) _z Si _1.0 N _1.5 , Nd _0.95 Zr _0.05 (Mo _8.3 Fe _91.7 ) _z Si _1.5 N _1.5 Samples were prepared. Then, analysis of the chemical composition, identification of the constituted phase, saturation magnetization (σs) and anisotropic magnetic field (H _A ) were measured. The results are shown in Table 3.
In the third example, the Fe amount (+ Co amount) + Mo amount (z) and Fe amount (+ Co amount) + Mo amount + Si amount with respect to the phase structure, saturation magnetization (σs) and anisotropic magnetic field ( _HA ) ( This is an experiment conducted to confirm the influence of z + u).

As shown in Table 3, when the Fe amount + Co amount + Mo amount (z) is less than 11 (Comparative Examples 5, 7, 8, 10), the saturation magnetization (σs) is less than 130 emu / g. On the other hand, when z is 13 (Comparative Example 9), a large amount of α-Fe precipitates and the characteristics deteriorate. Even if z is in the range of 11 to 12.5, z + u, that is, (Fe molar ratio + Co molar ratio + Mo molar ratio + Si molar ratio) / (R1 molar ratio + R2 molar ratio) At 11.6 and 12 or less (Comparative Example 6), the saturation magnetization (σs) shows a value of 130 emu / g or more, but the anisotropic magnetic field ( _HA ) remains at a value of 40 kOe or less.
On the other hand, Examples 12 to 17 in which z is in the range of 11 to 12.8 and z + u is greater than 12 have a saturation magnetization (σs) of 130 emu / g or more and an anisotropic magnetic field (H of 50 kOe or more). _A ).

(Fourth embodiment)
In the same manner as in the first example, Nd _0.95 Zr _0.05 (Mo _y Fe _100-y ) ₁₂ Si _1.0 N _1.5 , Nd _0.95 Zr _0.05 (Mo _y Fe _100-y ) _A sample was prepared to have a composition of ₁₂ Si _1.5 N _1.5 , Nd _0.95 Zr _0.05 (Mo _y Fe _100-y ) ₁₂ Si _2.0 N _1.5 , and the chemical composition Analysis, identification of constituent phases, saturation magnetization (σs), and measurement of anisotropic magnetic field ( _HA ) were performed. The results are shown in Table 4.
The fourth example is an experiment conducted to confirm the influence of the Mo amount (y) on the phase configuration, the saturation magnetization (σs), and the anisotropic magnetic field ( _HA ).

When the amount of Si (u) is 1.5 or 2.0 and the amount of Mo (y) is less than 5.0, α-Fe and further the 2-17 phase precipitate, and the saturation magnetization (Σs) and the anisotropic magnetic field (H _A ) remain low (Comparative Examples 12 and 13). On the other hand, when the Mo amount (y) exceeds 12.5 and 12.3, the saturation magnetization (σs) decreases to less than 120 emu / g (Comparative Example 11).
On the other hand, Examples 18 to 27 in which the Mo amount (y) is in the range of 5 to 12.3 have a structure of 1-12 phase single phase, in other words, a hard magnetic phase single phase, and 130 or 140 emu. / G or higher saturation magnetization (σs) and 50 or 55 kOe or higher anisotropic magnetic field (H _A ).

(5th Example)
In the same manner as in the first example, a sample was prepared to have a composition of Nd _0.95 Zr _0.05 (Mo _y Fe _100-y ) ₁₂ Si _1.0 N _v , and the chemical composition was analyzed and configured. Phase identification, saturation magnetization (σs) and anisotropic magnetic field (H _A ) were measured. The results are shown in Table 5.
The fifth example is an experiment conducted to confirm the influence of the N amount (v) on the phase structure, saturation magnetization (σs), and anisotropic magnetic field ( _HA ).

When the N amount (v) is 0 and 0.4, both the saturation magnetization (σs) and the anisotropic magnetic field ( _HA ) are low (Comparative Examples 14 and 15). On the other hand, when the N amount (v) exceeds 3.5 and 3, Nd nitride and α-Fe precipitate (Comparative Example 16).
In contrast, Examples 28 to 30 in which the N amount (v) is in the range of 1 to 3 have a 1-12 phase single phase, in other words, a hard magnetic phase single phase structure, and 130 emu / g or more. Saturation magnetization (σs), an anisotropic magnetic field (H _A ) of 45 or 50 kOe or more can be obtained. From the viewpoint of saturation magnetization (σs) and anisotropic magnetic field ( _HA ), the N content (v) is preferably in the range of 0.5 to 2.7, and more preferably 1.0 to 2.5.

(Sixth embodiment)
In the same manner as in the first embodiment, Nd _0.95 Zr _0.05 (Mo _8.3 Fe _91.7-w Co _w ) ₁₂ Si _0.25 N _1.5 , Nd _0.95 Zr _0.05 (Mo _8.3 Fe _91.7-w Co _w ) ₁₂ Si _1.0 N A sample is prepared to have a composition of _1.5 , and identification of phases to be constituted, saturation magnetization (σs), and anisotropic magnetic field Measurement of ( _HA ) was performed. The results are shown in Table 6.
The sixth example is an experiment conducted to confirm the influence of the Co amount (w) on the phase structure, saturation magnetization (σs), and anisotropic magnetic field ( _HA ).

In both cases where the Si amount (u) is 0.25 and 1.0, increasing the Co amount (w) improves the saturation magnetization (σs) and the anisotropic magnetic field ( _HA ), and the Co amount. It can be seen that the effect reaches a peak when (w) is about 20. Therefore, considering that Co is expensive, the Co amount (w) is desirably 30 or less, and more desirably in the range of 10 to 25. Further, in this range of Co amount (w), the structure is a single phase of 1-12 phase.

(Seventh embodiment)
High-purity Nd, Zr, Fe, Mo, Si metal is used as a raw material, and the composition of the alloy is Nd _0.95 Zr _0.05 (Mo _8.3 Fe _91.7-w Co _w ) ₁₂ Si _u. Thus, the sample was produced by the arc melting method in Ar atmosphere. Subsequently, this alloy was pulverized by a stamp mill, passed through a sieve having an opening of 38 μm, mixed with C powder having an average particle size of 1 μm or less, and maintained in an Ar atmosphere at a temperature of 400 to 600 ° C. for 24 hours. A heat treatment was performed. About each sample after heat processing, while analyzing a chemical composition and identifying the phase comprised, the saturation magnetization ((sigma) s) and the anisotropic magnetic field ( _HA ) were measured. The results are shown in Table 7.

By adding C instead of N, it is possible to obtain a single phase structure of 1-12 phase, 130 or 140 emu / g or more saturated magnetization ([sigma] s), 40 kOe or more anisotropy field _{(H A} ) Can be obtained. At this time, C plays the same role as N.

(Eighth embodiment)
In the same manner as in the first example, a sample was prepared so as to have a composition of Nd _1-x Hf _x (Mo _8.3 Fe _91.7 ) ₁₂ Si _1.0 N _1.5 , and analysis of chemical composition The phase to be constructed was identified, and the saturation magnetization (σs) and the anisotropic magnetic field (H _A ) were measured. The results are shown in Table 8.
The eighth example is an experiment conducted to confirm the effect of adding Hf instead of Zr.
As shown in Table 8, Hf has the same effect as Zr.

It is a chart which shows the result of the X-ray diffraction of the sample obtained by the Example of this invention and the comparative example. It is a chart which shows the result of the X-ray diffraction of the sample obtained by the Example of this invention and the comparative example.

Claims (3)

General formula: R1 _1-x R2 _x (Mo _y Fe _100- yw _Cow ) _z Si _{u Av} (where R1 is one or more of rare earth elements including Y and 50% or more thereof) Nd, R2 is one or two of Zr and Hf, A is one or two of N and C), and the molar ratio of the general formula is x = 0.18 or less, y = 5 to 12 .3, z = 11 to 12.8, u = 0.1 to 2.3, v = 0.5 to 3, w = 0 to 30 and (molar ratio of Fe + molar ratio of Co + mol of Mo) Ratio + Si molar ratio) / (R1 molar ratio + R2 molar ratio)> 12. The hard magnetic composition according to claim 1, wherein the hard magnetic composition includes a ThMn ₁₂ type crystal structure.   The hard magnetic composition according to claim 1, wherein x is 0.04 to 0.06.

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