JP2005171302A - Hard magnetic composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hard magnetic composition with which a ThMn<SB>12</SB>phase can be easily formed even if Nd is used as a rare earth element, particularly, to provide a hard magnetic composition with a single phase structure of a ThMn<SB>12</SB>phase, i.e., of a hard magnetic phase even if Nd is 100%. <P>SOLUTION: The hard magnetic composition is represented by the general formula: R(Fe<SB>100-y-w</SB>Co<SB>w</SB>Mo<SB>y</SB>)<SB>x</SB>Si<SB>z</SB>A<SB>v</SB>(R is one or more kinds selected from rare earth elements, and ≥50 mol% thereof is Nd; and A is one or two kinds of N and C); regarding the molar ratio in the general formula, x=10 to 12.6; y=(8.3-1.7×z) to 12; z =0.4 to 2.3; v=0.1 to 3; and w=0 to 30; and further, (the molar ratio of Fe+the molar ratio of Co+the molar ratio of Mo+the molar ratio of Si)/(the molar ratio of R)>12 is satisfied. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a hard magnetic composition suitable as 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, Patent Document 1 (Japanese Patent Laid-Open No. 63-273303) and Patent Document 2 (Japanese Patent Laid-Open No. 5-65603). ) And Patent Document 3 (Japanese Patent Laid-Open No. 2000-114017).
Patent Document 1 has the 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, in weight percentage) 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). Patent Document 1 states that the A element enters between atoms and changes the distance between Fe in a preferable direction.

  In Patent Document 2, R is Y, Th and a combination of one or more elements selected from the group consisting of all lanthanoid elements, and X is N (nitrogen) or B (boron) or C (carbon). ) Or a combination of these elements, the atomic percentage includes R: 3 to 30%, X: 0.3 to 50%, the balance is substantially composed of Fe, and the main phase is a body-centered tetragonal structure. An iron-rare earth permanent magnet material having the following is disclosed. In Patent Document 2, a part of Fe is selected from the group 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 a selected one or a combination of two or more elements. In Patent Document 2, the element M is positioned as an element having a great effect in generating a body-centered tetragonal structure.

Further, Patent Document 3, the general formula _{(R 1-u M u)} (Fe 1-vw Co v T w) x A y (R in the formula, M, T, A, respectively R: rare earth containing Y At least one element selected from elements, at least one element selected from M: Ti, Nb, T: at least one element selected from Ni, Cu, Sn, V, Ta, Cr, Mo, W, Mn, 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, 0 ≦ v ≦ 0.8, 0, respectively. ≦ 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 magnetic material is disclosed. In Patent Document 3, the amount of Si, Ge, and the like, which are stabilizing elements of a phase having a ThMn ₁₂ type crystal structure (hereinafter sometimes referred to as a ThMn ₁₂ phase) can be reduced by substituting the R element with the M element. It is stated.

JP 63-273303 A (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. Therefore, it is desirable that Nd, which is cheaper than expensive Sm, is the main element of the rare earth element. However, when Nd is used, it is difficult to generate a ThMn ₁₂ phase, and many non-magnetic impurities and high-temperature, long-time heat treatment are required for the generation. In addition, sufficient characteristics could not be obtained because many nonmagnetic impurities were used. For example, in the above-mentioned Patent Document 2, annealing is performed at 900 ° C. for 7 days, and in Patent Document 3, only Sm is used as a rare earth element with some exceptions.
Therefore, 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.

The present inventor can easily produce and obtain a phase having a ThMn ₁₂ type crystal structure even when Nd is used as a rare earth element by simultaneously adding predetermined amounts of Mo and Si to R and Fe. It has been found that by adding N and / or C to the compound, sufficient characteristics can be obtained as a hard magnetic composition for permanent magnets.

The present invention has been made based on the above findings, the general formula _{R (Fe 100-yw Co w} Mo y) x Si z A v ( Part 50 together with R is one or more rare earth elements The molar ratio is Nd, A is one or two of N and C), and the molar ratio of the general formula is x = 10 to 12.6, y = (8.3-1.7 × z) -12, z = 0.4 to 2.3, v = 0.1 to 3, w = 0 to 30 and (molar ratio of Fe + molar ratio of Co + molar ratio of Mo + molar ratio of Si) / ( It is a hard magnetic composition characterized by satisfying a molar ratio of R)> 12.
The hard magnetic composition according to the present invention can have a single phase of ThMn ₁₂ phase, which is a hard magnetic phase, by setting the above composition range.
Even if 70 mol% or more of R is Nd, the structure of the hard magnetic composition of the present invention can have a single phase of ThMn ₁₂ phase.

According to the present invention described above, an R—Mo—Fe—Si—A compound or an R—Mo—Fe—Co—Si—A compound (R is one or more rare earth elements and 80 mol% thereof) The above is composed of Nd, A is one or two of N and C), is composed of a single-phase structure of a hard magnetic phase, has a saturation magnetization (σs) of 110 emu / g or more, and an anisotropic magnetic field (H _A ). A hard magnetic composition that is 30 kOe or more is provided. Since this hard magnetic composition occupies 80 mol% or more of R with Nd, it has a cost advantage in obtaining a permanent magnet.

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, a hard magnetic composition comprising a ThMn ₁₂ phase, in other words, a single-phase structure of a hard magnetic phase, can be obtained even if Nd is 100%.

The reason for limitation of each element in this invention is demonstrated.
<R (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 R 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 R with Nd. However, the present invention allows a rare earth element other than Nd to be included. In addition, the rare earth element in this invention has the concept containing Y. 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 R 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 R is only Nd, that is, even when Nd occupies 100% of R, a single-phase structure composed of a ThMn ₁₂ phase that is a hard magnetic phase is obtained. be able to.

<Si>
Si is added to R (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 the ThMn ₁₂ phase lattice and reducing the crystal lattice. When the amount of Si is less than 0.4 (molar ratio, the same applies hereinafter), 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 is It tends to precipitate. Therefore, in the present invention, it is recommended that z, which is the amount of Si, be in the range of 0.4 to 2.3. A desirable Si amount (z) is 0.5 to 2.0, and a more desirable Si amount (z) is 0.5 to 1.0. Note that Si is included so as to satisfy the relationship of Fe, Co, Mo, and R (Fe molar ratio + Co molar ratio + Mo molar ratio + Si molar ratio) / (R molar ratio)> 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 obtain this effect sufficiently, it is necessary to set the lower limit of the Mo amount (y) in relation to the Si amount. That is, as shown in the Examples described later, when the Mo amount (y) is less than (8.3-1.7 × z (Si amount)), α-Fe and Mn ₂ Th ₁₇ phases are precipitated. Further, when the Mo amount (y) exceeds 12, the saturation magnetization is remarkably reduced. Therefore, in this invention, Mo amount (y) shall be (8.3-1.7 * z (Si amount))-12. Desirable Mo amount (y) is (8.3-1.7 × z (Si amount))-10, and more desirable Mo amount (y) is (8.3-1.7 × z (Si amount))-9. It is.
When the sum (x) of the Fe amount and the Mo amount is less than 10, both the saturation magnetization and the anisotropic magnetic field are low, and when it exceeds 12.6, α-Fe is precipitated. Therefore, in the present invention, the sum (x) of the Fe amount and the Mo amount is set to 10 to 12.6. A desirable sum (x) of the Fe amount and the Mo amount is 11 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 0.1 or less, the effect of improving magnetic properties cannot be obtained sufficiently. Therefore, in the present invention, the A amount (v) is set to 0.1 to 3. A desirable A amount (v) is 0.3 to 2.5, and a more desirable A amount (v) is 1 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 (σs) and the anisotropic magnetic field (H _A ) increase 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) / (R molar ratio)>12>
The individual contents of Fe, Co, Mo, and Si are as described above, but satisfying the condition of (Fe + Co + Mo + Si) / R> 12 when the hard magnetic composition of the present invention has a single phase structure of ThMn ₁₂ phase. It is important to. As shown in the examples described later, the saturation magnetization is low when the above conditions are not satisfied.

The hard magnetic composition according to the present invention can be obtained by a known production 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 the 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 gases that can infiltrate C include CH ₄ and C ₂ H ₆ . 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.

<First embodiment>
Using high-purity Nd, Fe, Mo, and Si metal as raw materials, a sample is prepared by arc melting in an Ar atmosphere so that the alloy composition is Nd- (Mo _8.3 Fe _91.7 ) ₁₂ -Si _z. did. 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 measurement of the X ray diffraction method and the thermomagnetic curve. X-ray diffraction was measured using a Cu tube at an output of 15 kW, and the presence or absence of peaks other than the ThMn ₁₂ phase was confirmed. However, since the peak of the Mn ₂ Th ₁₇ phase substantially coincides with the peak of the ThMn ₁₂ phase, it may be difficult to confirm only by the X-ray diffraction method, and a thermomagnetic curve is also used to identify the constituted phase. Further, the thermomagnetic curve was measured by applying a magnetic field of 2 kOe, and the presence or absence of expression of Tc (Curie temperature) corresponding to a phase other than the ThMn ₁₂ phase was confirmed. In the present invention, “a single-phase structure of ThMn ₁₂ phase” means that a peak of a phase other than ThMn ₁₂ phase is not observed by the above X-ray diffraction method, and ThMn is measured by measurement of the above thermomagnetic curve. Tc corresponding to a phase other than the ₁₂ phase is not confirmed, and the magnetization remaining on the higher temperature side than the Tc is 0.05 or less, which includes inevitable impurities and unreacted substances that are not detected. It doesn't matter. For example, in arc melting, the thermal uniformity during melting is insufficient, a slight unreacted phase (for example, Nd, α-Fe, etc.) may remain, and Cu from the sample holder is included as an inevitable impurity. However, this is not considered unless detected by X-ray diffraction and thermomagnetic curve measurements. A specific example relating to identification of the phase to be configured will be described with reference to FIGS.

FIG. 1 is a chart showing X-ray diffraction measurement results of Examples 2 and 25 and Comparative Example 3 described later, and a peak indicating a ThMn ₁₂ phase was observed. However, in Comparative Example 3, an α-Fe peak can be confirmed. As described above, since the peak of the Mn ₂ Th ₁₇ phase overlaps the peak of the ThMn ₁₂ phase, the two cannot be distinguished on this chart. FIG. 2 shows thermomagnetic curves of Examples 2 and 25 and Comparative Examples 3 and 11. ThMn ₁₂ phase Tc exists in the vicinity of 400 ° C. Further, the Tc of the Mn ₂ Th ₁₇ phase (2-17 phase) is confirmed on the lower temperature side than the Tc of the ThMn ₁₂ phase as shown in FIG. 2 (Comparative Example 11). Here, Tc other than Tc of the ThMn ₁₂ phase was not confirmed, and when the magnetization remaining on the higher temperature side than this Tc was 0.05 or less, it was recognized as a single phase. That is, in Examples 2 and 25, Tc other than Tc of the ThMn ₁₂ phase was not confirmed, and the magnetization remaining on the higher temperature side than this Tc was 0.05 or less, so that it was identified as a single phase structure of the ThMn ₁₂ phase. did. In Comparative Example 3, although Tc other than Tc of ThMn ₁₂ phase is not confirmed, from that as in FIG. 1, the magnetization remaining from the Tc at the high temperature side is greater than 0.05, other ThMn ₁₂ phase To which α-Fe is precipitated. Further, in Comparative Example 11, since the Tc of the Mn ₂ Th ₁₇ phase is confirmed and the magnetization remaining on the higher temperature side than the Tc of the ThMn ₁₂ phase exceeds 0.05, Mn _{2 in} addition to the ThMn ₁₂ phase The Th ₁₇ phase and α-Fe are identified as precipitated.
As described above, in both FIG. 1 (X-ray diffraction) and FIG. 2 (thermomagnetic curve), in the present invention, when no phase other than the ThMn ₁₂ phase is confirmed, the present invention has a single phase structure of the ThMn ₁₂ phase. Define that there is.

Further, 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 saturation magnetization (σs) value.

As shown in Table 1, Comparative Example 1 in which Si is not added and Comparative Example 2 in which the Si amount is as small as 0.3 are Mn ₂ Th ₁₇ phase in addition to ThMn ₁₂ phase (hereinafter referred to as 1-12 phase). (Hereinafter referred to as 2-17 phase) and α-Fe are present, and the anisotropic magnetic field ( _HA ) is particularly low. On the other hand, in Examples 1-4 in which Si is included within the scope of the present invention, it is understood that the 1-12 phase becomes a single phase and the 1-12 phase is stabilized. The compositions of these 1-12-phase single-phase can be obtained 120 emu / g or more saturated magnetization ([sigma] s), or more anisotropy field 50kOe (H _A). However, if the amount of Si exceeds 2.5 and 2.3, α-Fe precipitates in Comparative Example 3 and the characteristics deteriorate. In Comparative Example 4 in which the Fe amount + Mo amount is less than 10 and the Si amount is 2.5, both the saturation magnetization (σs) and the anisotropic magnetic field (H _A ) are remarkably reduced. 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 a permanent magnet that requires a coercive force.
In the ranges of Examples 1 to 4, the anisotropic magnetic field ( _HA ) is higher as the Si amount is larger, and conversely, the saturation magnetization (σs) tends to be higher as the Si amount is smaller.

<Second embodiment>
In the same manner as in the first example, a sample was prepared so as to have a composition of Nd— (Mo _8.3 Fe _91.7 ) _x —Si _z —N _1.5 , and analysis of chemical composition, identification of the constituted phase, saturation magnetization ( σs) and anisotropic magnetic field (H _A ) were measured. The results are shown in Table 2.
The second example is for confirming the influence of x (Fe amount + Mo amount) and x + z (Fe amount + Mo amount + Si amount) on the phase structure, saturation magnetization (σs) and anisotropic magnetic field ( _HA ). This is an experiment conducted in

As shown in Table 2, when x (Fe amount + Mo amount) is less than 10 (Comparative Examples 5 and 9), the saturation magnetization (σs) is less than 110 emu / g. On the contrary, when x (Fe amount + Mo amount) exceeds 12.6 (Comparative Examples 8 and 10), α-Fe is precipitated. Even if x is in the range of 10 to 12.6, when x + z is 12 or less (Comparative Examples 6 and 7), the saturation magnetization (σs) is less than 110 emu / g, and the anisotropic magnetic field (H _A ). Is as low as about 30 kOe.
In contrast, when x is in the range of 10 to 12.6 and x + z exceeds 12 (Examples 5 to 11), saturation magnetization (σs) of 110 emu / g or more, anisotropic of 50 kOe or more It has a characteristic of a sexual magnetic field (H _A ), and a 1-12 phase single phase structure can be obtained.

<Third embodiment>
In the same manner as in the first embodiment _{Nd- (Mo y Fe 100-y} ) -Si 1.0 -N 1.5, prepare a sample so as to have the composition of _{Nd- (Mo y Fe 100-y} ) -Si 1.5 -N 1.5 Then, analysis of the chemical composition, identification of the constituted phase, measurement of saturation magnetization (σs) and anisotropic magnetic field (H _A ) were performed. The results are shown in Table 3.
The third example is an experiment conducted to confirm the influence of y (Mo amount) on the phase structure, saturation magnetization (σs), and anisotropic magnetic field ( _HA ).

As shown in Table 3, y (Mo amount) is less than (8.3-1.7 × z) in both cases of z (Si amount) of 1.0 and 2.0 (Comparative Examples 11 and 12). 14), α-Fe and further a 2-17 phase are precipitated. On the other hand, when y (Mo amount) exceeds 12.5 and 12.0 (Comparative Example 13), the saturation magnetization (σs) decreases to less than 110 emu / g.
On the other hand, when y (Mo amount) is in the range of (8.3-1.7 × z) to 12, a 1-12 phase single phase, in other words, a hard magnetic phase single phase structure, and 110 or 130 emu / g or more saturated magnetization ([sigma] s), can be obtained 45 or 50kOe or more anisotropy field (H _a) (example 12 to 19).

<Fourth embodiment>
In the same manner as in the first example, a sample was prepared so as to have a composition of Nd— (Mo _8.3 Fe _91.7 ) ₁₂ —Si _2.0 —N _v , 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 4.
The fourth example is an experiment conducted to confirm the influence of v (N amount) on the phase configuration, saturation magnetization (σs), and anisotropic magnetic field ( _HA ).

As shown in Table 4, when v (N content) is 0, both the saturation magnetization (σs) and the anisotropic magnetic field (H _A ) are low (Comparative Example 15). On the other hand, when v (N amount) exceeds 3.5 and 3, α-Fe precipitates (Comparative Example 16).
On the other hand, when v (N content) is in the range of 0.1 to 3, a 1-12 phase single phase, in other words, a hard magnetic phase single phase structure, and a saturation magnetization of 115 emu / g or more ( [sigma] s), an anisotropic magnetic field ( _HA ) of 30 kOe or more can be obtained (Examples 20 to 23). From the viewpoint of saturation magnetization (σs) and anisotropic magnetic field ( _HA ), v (N content) is preferably in the range of 0.5 to 2.7, more preferably 1 to 2.5.

<Fifth embodiment>
Each sample shown in Table 5 was prepared in the same manner as in the first example, and the identification of the phase to be constituted, the saturation magnetization (σs), and the measurement of the anisotropic magnetic field ( _HA ) were performed. The results are shown in Table 5.
Incidentally, the fifth embodiment is an _{Nd- (Mo 8.3 Fe 91.7-w} Co w) 12 -Si z w (Co amount) in -N _1.5 to confirm the dependence experiments.

As shown in Table 5, the saturation magnetization (σs) and the anisotropic magnetic field (H _A ) are increased when w (Co content) is increased regardless of whether z (Si content) is 0.5 or 1.0. It can be seen that the effect is peaked when w (Co content) is about 20. Therefore, considering that Co is expensive, w (Co amount) is preferably 30 or less, and more preferably in the range of 10 to 25. Further, in this range of w (Co amount), the structure is a single phase of 1-12 phase.

<Sixth embodiment>
High purity Nd, Fe, Mo, and Si metal, used as a raw material, so as to have the composition of _{Nd- (Mo 8.3 Fe 91.7-w} Co w) 12 -Si z as the alloy composition, arc melting in an Ar atmosphere A sample was prepared by the method. 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. Heat treatment (carbonization) 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 6.

As shown in Table 6, by adding C instead of N, a 1-12 phase single-phase structure can be obtained, a saturation magnetization (σs) of 120 emu / g or more, and an anisotropic of 30 kOe or more. _A magnetic field (H _A ) can be obtained. At this time, C plays the same role as N.
Moreover, even when 1 to 25% of Nd is substituted with Pr, the same result as in the example can be obtained.

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 thermomagnetic curve of the sample obtained by the Example of this invention and the comparative example.

Claims (4)

Formula _{R (Fe 100-yw Co w} Mo y) x Si z A v (R is more than the 50 mol% with is one or more rare earth elements are Nd, A is one of N and C or The molar ratio of the general formula is
x = 10 to 12.6,
y = (8.3-1.7 × z) to 12,
z = 0.4-2.3,
v = 0.1-3,
w = 0 to 30 and
A hard magnetic composition characterized by satisfying (Fe molar ratio + Co molar ratio + Mo molar ratio + Si molar ratio) / (R molar ratio)> 12. The hard magnetic composition according to claim 1, wherein the hard magnetic composition is composed of a single-phase structure of a phase having a ThMn ₁₂ type crystal structure.   The hard magnetic composition according to claim 1, wherein 70 mol% or more of R is Nd. R-Mo-Fe-Si-A compound or R-Mo-Fe-Co-Si-A compound (R is one or more rare earth elements and 80 mol% or more thereof is Nd, A is N and 1 type or 2 types of C), and is composed of a single-phase structure of a hard magnetic phase, characterized by a saturation magnetization (σs) of 110 emu / g or more and an anisotropic magnetic field ( _HA ) of 30 kOe or more. Hard magnetic composition.

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