JP2019179796A - Rare earth magnet and manufacturing method thereof - Google Patents

Abstract

To provide: a rare earth magnet enhanced in both of a coercive force and magnetization while suppressing a Nd use amount of Nd-Fe-B based rare earth magnet; and a manufacturing method of the rare earth magnet.SOLUTION: Disclosed are a rare earth magnet and a manufacturing method thereof. The rare earth magnet has a total composition represented by the formula, (NdCeR)(FeCo)BGaM(where Ris at least one kind selected from a rare earth element other than Nd and Ce, and Y, and M is at least one kind selected from Al, Cu, Au, Ag, Zn, In, Mn, Zr and Ti, and an inevitable impurity element, and 12≤p≤20, 4.0≤q≤6.5, 0≤r≤1.0, 0≤s≤0.5, 0<x≤0.35, 0≤y≤0.10 and 0.050≤z0.140), and comprises magnetic phases and grain boundary phases which are present around the magnetic phases.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a rare earth magnet and a manufacturing method thereof. The present disclosure particularly relates to an R-T-B rare earth magnet (R is a rare earth element, and T is a transition metal element).

  The RTB-based rare earth magnet is a high-performance magnet having excellent magnetic properties. Therefore, in addition to motors constituting hard disks and MRI (magnetic resonance imaging) devices, they are used in drive motors for hybrid vehicles and electric vehicles.

  Of R-T-B rare earth magnets, R is Nd and T is Fe rare earth magnet, that is, Nd-Fe-B rare earth magnet is most representative. However, the price of Nd has been rising, and an attempt has been made to replace part of Nd in the Nd-Fe-B rare earth magnet with Ce, La, Y, and / or Sc, which is cheaper than Nd. ing.

For example, in Patent Document 1, (R ² _(1-x) R ¹ _x ) _y Fe _100-ywzv Co _{w Bz} TM _v (R ² is Nd or Pr, R ¹ is Ce, La, Gd, Y, Sc is at least one alloy or two or more alloys, TM is at least one of Ga, Al, Cu, Au, Ag, Zn, In, Mn, and 0 <x <1, y = 12-20, z = 5.6-6.5, w = 0-8, v = 0) A rare earth magnet having a composition is disclosed.

Japanese Patent No. 6183457

The Nd—Fe—B rare earth magnet includes a magnetic phase represented by Nd ₂ Fe ₁₄ B and a grain boundary phase existing around the magnetic phase. When a part of Nd in the Nd—Fe—B rare earth magnet is replaced with a light rare earth element such as Ce, La, and Sc, the magnetic properties, particularly the coercive force, are lowered.

  In order to compensate for the decrease in the coercive force, a modified alloy is diffused and penetrated into the grain boundary phase to achieve magnetic separation between the magnetic phases. However, when the modified alloy is diffused and infiltrated, the content of the nonmagnetic component increases, so that the magnetization tends to decrease.

  On the other hand, with the expansion of the field of use of Nd-Fe-B rare earth magnets, the scarcity of Nd is further increasing, and both coercive force and magnetization are improved in a balanced manner while suppressing the amount of Nd used. Is required.

  For these reasons, the present inventors have found that it is required to improve both the coercive force and the magnetization while suppressing the amount of Nd that is highly rare.

  This indication is made in order to solve the above-mentioned subject. An object of the present disclosure is to provide a rare earth magnet having both the coercive force and the magnetization improved while suppressing the amount of Nd used in the Nd-Fe-B rare earth magnet and a method for manufacturing the rare earth magnet.

In order to achieve the above object, the present inventors have made extensive studies and completed the rare earth magnet of the present disclosure and a manufacturing method thereof. The aspect is as follows.
<1> the total composition has the formula ^{_{(Nd (1-x-y}} ) Ce x R 1 y) p (Fe (1-z) Co z) (100-p-q-r-s) B q Ga r M _s (where R ¹ is at least one selected from rare earth elements other than Nd and Ce and Y, and M is one selected from Al, Cu, Au, Ag, Zn, In, Mn, Zr, and Ti) And inevitable impurity elements, and
12 ≦ p ≦ 20,
4.0 ≦ q ≦ 6.5,
0 ≦ r ≦ 1.0,
0 ≦ s ≦ 0.5,
0 <x ≦ 0.35,
0 ≦ y ≦ 0.10 and 0.050 ≦ z0.140), and
A magnetic phase, and a grain boundary phase present around the magnetic phase,
Rare earth magnet.
<2> The rare earth magnet according to <1>, wherein x is 0.10 ≦ x ≦ 0.30.
<3> The rare earth magnet according to <1> or <2>, wherein z is 0.055 ≦ z ≦ 0.100.
<4> The rare earth magnet according to any one of <1> to <3>, wherein r is 0.1 ≦ r ≦ 1.0.
<5> The rare earth magnet according to any one of <1> to <4>, wherein an average particle diameter of the magnetic phase is 1-1000 nm.
<6> The rare earth magnet according to any one of <1> to <4>, wherein an average particle size of the magnetic phase is 50 to 500 nm.
<7> formula ^{_{(Nd (1-x-y}} ) Ce x R 1 y) p (Fe (1-z) Co z) (100-p-q-r-s) B q Ga r M s ( provided that R ¹ is one or more selected from rare earth elements other than Nd and Ce and Y, M is one or more selected from Al, Cu, Au, Ag, Zn, In, Mn, Zr, and Ti, and unavoidable An impurity element, and
12 ≦ p ≦ 20,
4.0 ≦ q ≦ 6.5,
0 ≦ r ≦ 1,
0 ≦ s ≦ 0.5,
0 <x ≦ 0.35,
Preparing a magnetic powder having a composition represented by 0 ≦ y ≦ 0.10 and 0.05 ≦ z ≦ 0.14),
Hot pressing the magnetic powder to obtain a compact, and hot plastic working the compact,
including,
A method for producing a rare earth magnet.
<8> The method according to <7>, wherein x is 0.10 ≦ x ≦ 0.30.
<9> The method according to <7> or <8>, wherein z is 0.055 ≦ z ≦ 0.100.
<10> The method according to any one of <7> to <9>, wherein r is 0.1 ≦ r ≦ 1.0.
<11> The method according to any one of <7> to <10>, wherein the magnetic powder is obtained by a liquid quenching method.

  According to the present disclosure, a part of Nd of the Nd—Fe—B rare earth magnet is replaced with Ce, and a part of Fe is replaced with Co to reduce the lattice constant of the magnetic phase, thereby reducing the coercive force and the magnetization. It is possible to provide a rare earth magnet and a method for producing the same, both of which are improved.

FIG. 1 shows the ratio z of the Co content to the total content of Fe and Co for Examples 1 to 3, Comparative Examples 1 to 5, and Reference Examples 1 to 3, and Ce to the total content of Nd and Ce. It is a figure which shows the relationship of content x of.

  Hereinafter, embodiments of a rare earth magnet and a method for manufacturing the same according to the present disclosure will be described in detail. In addition, embodiment shown below does not limit the rare earth magnet which concerns on this indication, and its manufacturing method.

The Nd—Fe—B rare earth magnet includes a magnetic phase represented by Nd ₂ Fe ₁₄ B and a grain boundary phase existing around the magnetic phase (hereinafter, such a magnet is referred to as “Nd ₂ Fe ₁₄ B magnet ”). Then, when a part of Nd of the Nd ₂ Fe ₁₄ B magnet is replaced with Ce (hereinafter, such a magnet may be referred to as “(Nd, Ce) ₂ Fe ₁₄ B magnet”), Nd ₂ Fe ₁₄ B Compared to the magnet, the anisotropic magnetic field Ha and the saturation magnetization Ms of the (Nd, Ce) ₂ Fe ₁₄ B magnet are lowered. As the anisotropic magnetic field Ha decreases, the coercive force Hc also decreases. As the saturation magnetization Ms decreases, the residual magnetization Mr decreases.

Further, a CeFe ₂ phase exists in the grain boundary phase of the (Nd, Ce) ₂ Fe ₁₄ B magnet. Due to the presence of the CeFe ₂ phase, the magnetic separation between the magnetic phases is inhibited, and the coercive force Hc is lowered.

Therefore, when a part of Fe in (Nd, Ce) ₂ Fe ₁₄ B is replaced with Co, the presence of both Ce and Co results in the lattice constant of (Nd, Ce) ₂ (Fe, Co) ₁₄ B being to shrink. Since there is a relationship of (Nd atomic radius)> (Ce atomic radius) and (Fe atomic radius)> (Co atomic radius), the lattice constant of (Nd, Ce) ₂ (Fe, Co) ₁₄ B is reduced.

The density of the magnetic phase is improved by reducing the lattice constant of (Nd, Ce) ₂ (Fe, Co) ₁₄ B. When the density is improved, the residual magnetization Mr is improved by the magnetic volume effect.

In addition, by reducing the lattice constant of (Nd, Ce) ₂ (Fe, Co) ₁₄ B, the interaction between rare earth atoms and transition metal atoms (Fe atoms and Co atoms) is improved, and anisotropic magnetization is achieved. Ha is improved. As a result, the coercive force Hc is also improved.

_Furthermore, (Nd, Ce) when a part of Fe 2 _{Fe 14} B is substituted with Co, inhibit the stability of CeFe ₂ phase present in the grain boundary phase. As a result, the demagnetization of the grain boundary phase proceeds. As a result, the magnetic separation between the magnetic phases proceeds, and the coercive force Hc is improved.

From these facts, the present inventor shows that both the coercive force and the magnetization are improved by substituting part of Nd of the Nd ₂ Fe ₁₄ B magnet with Ce and part of Fe with Co. Found out.

  Based on these findings, the constituent requirements of the rare earth magnet and the manufacturing method thereof according to the present disclosure will be described below.

《Rare earth magnet》
First, constituent requirements of the rare earth magnet of the present disclosure will be described.

<Overall composition>
Component composition of the rare earth magnet of the present disclosure, the formula ^{_{(Nd (1-x-y}} ) Ce x R 1 y) p (Fe (1-z) Co z) (100-p-q-r-s) B q represented by Ga _r M _s. In this formula, R ¹ is at least one selected from rare earth elements other than Nd and Ce and Y. M is one or more selected from Al, Cu, Au, Ag, Zn, In, Mn, Zr, and Ti, and an unavoidable impurity element.

p is the total content of Nd, Ce, and ^{R 1.} q is the content of B. r is the Ga content. s is the content of M. The values of p, q, r, and s are each atomic%. Hereinafter, Nd, Ce, R ¹ , Fe, Co, B, Ga, and M will be described together with their contents.

<Nd>
Nd is a main element of the rare earth magnet of the present disclosure along with Ce. Nd forms a magnetic phase represented by (Nd, Ce) ₂ (Fe, Co) ₁₄ B together with Ce. The magnetic phase may contain R ¹ described later in place of Nd and Ce.

The content ratio of Nd is the balance of Ce and R ^{1 with} respect to the total content of Nd, Ce, and R ¹ . The content ratio (molar ratio) of Nd is represented by 1-xy. The Ce content ratio x and the R ¹ content ratio will be described later.

<Ce>
Ce, along with Nd, is a main element of the rare earth magnet of the present disclosure. Ce and Nd constitute a magnetic phase represented by (Nd, Ce) ₂ (Fe, Co) ₁₄ B. The magnetic phase may contain R ¹ described later in place of Nd and Ce.

By substituting part of Nd of the Nd ₂ Fe ₁₄ B magnet with Ce and further substituting part of Fe with Co, the lattice constant of (Nd, Ce) ₂ (Fe, Co) ₁₄ B is reduced. . _{(Nd, Ce) 2 (Fe} , Co) 14 effects the lattice constant can be obtained by reduction of B is as described above.

The Ce content ratio is a molar ratio x with respect to the sum of Nd, Ce, and R ¹ . In order to reduce the lattice constant described above, the inclusion of Ce is indispensable. Therefore, the Ce content ratio x is greater than zero. From the viewpoint of obtaining a lattice constant reduction effect, x is preferably 0.10 or more, and more preferably 0.15 or more. On the other hand, if x is 0.35 or less, the grain boundary phase, never CeFe ₂ phase contains a large amount. As a result, it contributes to the improvement of the coercive force Hc. From this viewpoint, x is preferably 0.30 or less, and more preferably 0.25 or less.

<R ¹ >
R ¹ is at least one selected from rare earth elements other than Nd and Ce and Y. In the rare earth magnet of the present disclosure, the main rare earth elements are Nd and Ce, but may include one or more selected from rare earth elements other than Nd and Ce and Y. Since R ¹ is an element that is inevitably contained due to the relationship between raw materials and manufacturing processes, the content ratio (molar ratio) y of R ¹ may be 0. Since setting R ¹ to 0 leads to an increase in manufacturing cost and the like, y may be 0.01 or more, 0.02 or more, or 0.03. Meanwhile, ^{R 1} is unless invited an increase in manufacturing costs, since better less, y is 0.10 or less, 0.08 or less, 0.06 or less, or 0.04 or less .

  In the present specification, unless otherwise specified, rare earth elements are Sc, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.

<Nd, Ce, and the total content of ^{R 1>}
The contents of Nd, Ce, and R ¹ are represented by p. If p is 12 atomic% or more, a desired amount of magnetic phase can be secured. From this viewpoint, p is preferably 13 atomic% or more, and more preferably 14 atomic% or more. On the other hand, when p is 20 atomic% or less, a large amount of CeFe ₂ phase does not exist in the grain boundary phase. From this viewpoint, p is preferably 18 atom% or less, and more preferably 16 atom% or less.

<Fe>
Fe is a main element of the rare earth magnet of the present disclosure. Fe forms a magnetic phase with Nd, Ce, R ¹ , and B together with Co.

<Co>
Co is a main element of the rare earth magnet of the present disclosure. When a part of Fe in (Nd, Ce) ₂ Fe ₁₄ B is substituted with Co, the lattice constant of (Nd, Ce) ₂ (Fe, Co) ₁₄ B is reduced. The effects obtained by reducing the lattice constant are as described above.

The content ratio of Co is expressed by a molar ratio z with respect to the total content of Fe and Co. If z is 0.050 or more, the above-described lattice constant reduction effect can be obtained. From this viewpoint, z is preferably 0.055 or more, and more preferably 0.057 or more. On the other hand, if z is at 0.140 or _{less, (Nd,} Ce) by 2 (Fe, _Co) distortion to the magnetic phase expressed by ₁₄ B occurs, no magnetic anisotropy Ha is reduced . Further, when z is 0.140 or less, a large amount of CeFe ₂ phase is not generated in the grain boundary phase. From these viewpoints, z is preferably 0.100 or less, more preferably 0.0900 or less, and even more preferably 0.0800 or less.

<Total content of Fe and Co>
The total content of Fe and Co is the balance of Nd, Ce, R ¹ , B, Ga, and M, and is expressed in (100-pqr-s) atomic%. The Ga content r (atomic%) and the M content s (atomic%) will be described later. The contents of Nd, Ce, R ¹ , B, Ga, and M are appropriately determined so that the magnetic phase in the rare earth magnet has a desired content.

<B>
B forms a magnetic phase together with Nd, Ce, R ¹ , Fe, and Co. When the content q of B is 4.0 atomic% or more, when the rare earth magnet raw material powder of the present disclosure is produced by a liquid quenching method, an amorphous structure is present inside the ribbon or the like relative to the entire rare earth magnet. And 10.0% by volume or more does not remain. From this viewpoint, q is preferably 4.5 atomic% or more, and more preferably 5.0 atomic% or more. On the other hand, if the content q of B is 6.5 atomic% or less, B that does not dissolve in Fe does not remain excessively in the grain boundary phase. From this viewpoint, the B content q is preferably 6.0 atomic percent or less, and more preferably 5.5 atomic percent or less.

<Ga>
Ga is optionally contained to adjust the interface between the magnetic phase and the grain boundary phase. This improves the magnetic properties of the rare earth magnet. Ga may not be contained (r = 0). From the viewpoint of clearly expressing the effect of Ga, the Ga content r is preferably 0.1 atomic% or more, more preferably 0.2 atomic% or more, and even more preferably 0.4 atomic% or more. . On the other hand, if the Ga content r is 1.0 atomic% or less, the above-described effect of Ga will not be saturated. From this viewpoint, r is preferably 0.8 atomic percent or less, and more preferably 0.6 atomic percent or less.

<M>
M is an element that can be contained as long as the characteristics of the rare earth magnet of the present disclosure are not impaired. M is one or more selected from Al, Cu, Au, Ag, Zn, In, Mn, Zr, and Ti, and an unavoidable impurity element. Inevitable impurities refer to impurities such as impurities contained in the raw material that cannot be avoided, or incurring a significant increase in manufacturing cost. When the M content s is 0.5 atomic% or less, the characteristics of the rare earth magnet of the present disclosure are not impaired. From this viewpoint, s is preferably 0.3 atomic percent or less, and 0 is ideal. However, excessively reducing the M content s leads to an increase in manufacturing cost, so s may be 0.10 atomic% or more.

<Magnetic phase>
The rare earth magnet of the present disclosure includes a magnetic phase. The composition of the magnetic phase is _{typically, (Nd, Ce) 2 (} Fe, Co) are represented by ₁₄ B, in ^which, R 1, Ga, and M may be applied.

  The particle size of the magnetic phase is not particularly limited, but the magnetic phase is preferably a nanocrystal in order to improve both the coercive force and the magnetization. The average particle size of the magnetic phase of the nanocrystal is preferably 1 to 1000 nm. The average particle size may be 50 nm or more, 100 nm or more, 200 nm or more, or 300 nm or more, and may be 900 nm or less, 800 nm or less, 700 nm or less, 600 nm, or 500 nm or less. In the present specification, the average particle size is defined as a certain region of the structure of the rare earth magnet in the scanning electron microscope image or the transmission electron microscope image, and each of the magnetic phases existing in the certain region. The projected area equivalent circle diameter is measured and averaged to obtain the “average particle diameter”.

The rare earth magnet of the present disclosure includes a grain boundary phase existing around the magnetic phase. The grain boundary phase is made (Nd, Ce, ^{R 1)} rich phase. In the grain boundary phase, when the molten metal having the composition of the rare earth magnet of the present disclosure is solidified, the residual liquid that has produced the magnetic phase is solidified. From this, the grain boundary phase is not clear in composition and structure, but the total content of Nd, Ce and R ¹ is higher in the grain boundary phase than in the magnetic phase.

Further, as described above, in the rare earth magnet of the present disclosure, the stability of the CeFe ₂ phase in the grain boundary phase is hindered, which contributes to the improvement of the coercive force Ha.

"Production method"
Next, the manufacturing method of the rare earth magnet of this indication is explained.

  As a method for producing a rare earth magnet of the present disclosure, a known method for producing a rare earth magnet can be applied. As a well-known manufacturing method, for example, an isotropic magnetic powder having nanocrystals is manufactured by a liquid quenching method, and an isotropic or anisotropic magnetic powder is manufactured by an HDDR (Hydrogen Disposition Decomposition Recombination) method. And the like.

  When the conventional rare earth magnet and the rare earth magnet of the present disclosure are manufactured by the same manufacturing method, a part of Nd is replaced with Ce and a part of Fe is replaced with Co according to the rare earth magnet of the present disclosure. Thus, the rare earth magnet of the present disclosure can obtain higher coercive force and magnetization.

  From the viewpoint of improving both the coercive force and the magnetization as much as possible, the magnetic powder used for manufacturing the rare earth magnet of the present disclosure is preferably manufactured by applying a quenching process such as a liquid quenching method.

  An outline of a method for obtaining a magnetic powder having a nanocrystalline structure by a liquid quenching method will be described. An alloy having the same composition as the entire composition of the rare earth magnet of the present disclosure is melted at high frequency to prepare a molten metal. In the case where a specific component volatilizes and / or wears out during the manufacturing process, the raw material may be blended in anticipation of the amount and a molten metal may be prepared.

  About the prepared molten metal, for example, in a Ar gas atmosphere decompressed to 50 kPa or less, the molten metal is discharged onto a single copper roll to produce a quenched ribbon. The quenched ribbon is pulverized to, for example, 10 μm or less. If the quenching ribbon contains a large amount of amorphous material, it may be nanocrystallized by heat treatment.

The conditions for liquid quenching when using a copper single roll may be appropriately determined so that the obtained ribbon has a nanocrystalline structure. Typically, the molten metal is cooled at 10 ³ to 10 ⁶ ° C / second.

  The melt discharge temperature is typically 1300 ° C. or higher, 1350 ° C. or higher, or 1400 ° C. or higher, and may be 1600 ° C. or lower, 1550 ° C. or lower, or 1500 ° C. or lower.

  When the single roll peripheral speed is 15 m / s or more, the crystal grains in the rapidly cooled ribbon are not easily coarsened. The peripheral speed of the single roll may typically be 20 m / s or more, 24 m / s or more, or 28 m / s or more, 40 m / s or less, 36 m / s or less, or 32 m / s or less. Good.

  The rare earth magnet of the present disclosure may be a magnetic powder, a bonded magnet obtained by solidifying a magnetic powder using a binder, or a molded body obtained by hot pressing a magnetic powder. It may be a plastic processed body obtained by subjecting the molded body to hot plastic processing. Or the sintered compact which sintered the green compact which pressed the magnetic powder in the magnetic field may be sufficient.

  From the viewpoint of improving both the coercive force and the magnetization, a method of obtaining a plastic workpiece is preferable. In this method, when magnetic powder having an isotropic nanocrystalline structure is hot-pressed to obtain a molded body, and further, the molded body is subjected to hot plastic working to obtain a plastic processed body having anisotropy. What is necessary is just to determine the conditions of each process suitably so that the plastic working body of this may be obtained. Typical conditions are as follows:

  The pressure at the time of hot pressing may be 200 MPa or more, 300 MPa or more, or 350 MPa or more, and may be 600 MPa or less, 500 MPa or less, or 450 MPa or less.

  The hot pressing temperature may be 550 ° C or higher, 600 ° C or higher, or 630 ° C or higher, and may be 750 ° C or lower, 700 ° C or lower, or 670 ° C or lower.

  The hot pressing time may be 2 seconds or more, 3 seconds or more, or 4 seconds or more, and may be 8 seconds or less, 7 seconds or less, or 6 seconds or less.

  The temperature during the hot plastic working of the molded body may be 700 ° C. or more, 710 ° C. or more, or 720 ° C. or more, and may be 900 ° C. or less, 800 ° C. or less, or 770 ° C. or less. When the temperature during hot plastic working is 780 to 850 ° C., high orientation can be obtained while suppressing the coarsening of crystal grains.

  The strain rate during hot plastic working of the molded body may be 0.01 / s or more, 0.1 / s or more, 1.0 / s or more, or 3.0 / s or more, and 10.0 / s. It may be s or less, 7.0 / s or less, or 5.0 / s or less. When the strain rate is 0.03 to 0.3 / s, high orientation can be obtained while suppressing the coarsening of crystal grains.

  If the rolling reduction is 60% or more, a desired orientation can be obtained. On the other hand, if the rolling reduction is 80 or less, the molded body is not damaged. The rolling reduction is preferably 60 to 80%, more preferably 70 to 75%.

  Examples of the hot plastic working method of the molded body include upsetting, forward extrusion, and backward extrusion.

  Hereinafter, the rare earth magnet of the present disclosure and the manufacturing method thereof will be described more specifically with reference to examples and comparative examples. In addition, the rare earth magnet of this indication and its manufacturing method are not limited to the conditions used in the following Examples.

<Sample preparation>
An alloy having the composition shown in Table 1 was prepared. In any sample, the contents of R ¹ and M are below the measurement limit. Therefore, since the content ratio y of R ¹ and the content s of M can be regarded as 0 and 0 atomic%, respectively, these content ratios and contents are not described in Table 1.

  The molten alloy of Table 1 was liquid quenched by a single roll method to obtain a ribbon. The liquid quenching conditions were a molten metal temperature (discharge temperature) of 1420 ° C. and a roll peripheral speed of 40 m / s. Liquid quenching was performed under an argon gas reduced pressure atmosphere. It was confirmed by transmission electron microscope (TEM) observation that the ribbon had nanocrystals.

  The ribbon was coarsely pulverized into a powder, and the powder was charged into a die and hot pressed to obtain a molded body. The hot pressing conditions were a pressing force of 400 MPa, a heating temperature of 650 ° C., and a holding time of 300 seconds.

  The molded body was hot upset (hot plastic working) to obtain a rare earth magnet. As hot upsetting conditions, the processing pressure was 850 MPa, the strain rate was 0.01 / s, and the rolling reduction was 75%. It was confirmed with a scanning electron microscope (SEM) that the plastic workpiece had an oriented nanocrystal structure.

(Evaluation)
For each sample, the coercive force Hc and the remanent magnetization Mr were measured. The measurement was performed at room temperature using a vibrating sample magnetometer (VSM: Vibrating Sample Magnetometer) manufactured by Lake Shore.

The effect of improving both the coercive force and the magnetization was evaluated by Hc × Mr per unit content of Nd. Hc × Mr per unit content of Nd is obtained by the following formula.
Hc × Mr / (1-x) [T · kA / m]
Hc: Coercive force [kA / m]
Mr: residual magnetization [T]
1-x: Nd content (molar ratio) with respect to the total content of Nd and Ce [-]

The evaluation results are shown in Table 1. In Table 1, Reference Example 2 is quoted from Comparative Example 1 of International Publication No. 2014 / 196605A1, and Reference Example 3 is Arjun K. et al. Pathak et al Adv. Mater. 2015, 27, 2663-2667. FIG. 1 shows the ratio z of the Co content to the total content of Fe and Co and the total of Nd and Ce for the samples of Examples 1 to 3, Comparative Examples 1 to 5, and Reference Examples 1 to 3. The relationship of the Ce content z to the content was shown.

  From Table 1, when evaluated by Hc × Mr per unit content ratio of Nd, compared with the samples of Comparative Examples 1 to 5 and Reference Examples 1 to 3, the samples of Examples 1 to 3 have a small Nd content, It can be understood that both the coercive force and the magnetization can be improved.

  From the above results, the effects of the rare earth magnet of the present disclosure and the manufacturing method thereof were confirmed.

Claims (11)

Total composition formula ^{_{(Nd (1-x-y}} ) Ce x R 1 y) p (Fe (1-z) Co z) (100-p-q-r-s) B q Ga r M s ( provided that , R ¹ is at least one selected from rare earth elements other than Nd and Ce and Y, M is at least one selected from Al, Cu, Au, Ag, Zn, In, Mn, Zr, and Ti, and unavoidable Impurity element, and
12 ≦ p ≦ 20,
4.0 ≦ q ≦ 6.5,
0 ≦ r ≦ 1.0,
0 ≦ s ≦ 0.5,
0 <x ≦ 0.35,
0 ≦ y ≦ 0.10 and 0.050 ≦ z0.140), and
A magnetic phase, and a grain boundary phase present around the magnetic phase,
Rare earth magnet.   The rare earth magnet according to claim 1, wherein x is 0.10 ≦ x ≦ 0.30.   The rare earth magnet according to claim 1, wherein z is 0.055 ≦ z ≦ 0.100.   The rare earth magnet according to claim 1, wherein r is 0.1 ≦ r ≦ 1.0.   The rare earth magnet according to any one of claims 1 to 4, wherein an average particle diameter of the magnetic phase is 1-1000 nm.   The rare earth magnet according to any one of claims 1 to 4, wherein an average particle diameter of the magnetic phase is 50 to 500 nm. Formula ^{_{(Nd (1-x-y}} ) Ce x R 1 y) p (Fe (1-z) Co z) (100-p-q-r-s) B q Ga r M s ( provided that, ^{R 1} is , One or more selected from rare earth elements other than Nd and Ce and Y, M is one or more selected from Al, Cu, Au, Ag, Zn, In, Mn, Zr, and Ti, and inevitable impurity elements Yes, and
12 ≦ p ≦ 20,
4.0 ≦ q ≦ 6.5,
0 ≦ r ≦ 1,
0 ≦ s ≦ 0.5,
0 <x ≦ 0.35,
Preparing a magnetic powder having a composition represented by 0 ≦ y ≦ 0.10 and 0.05 ≦ z ≦ 0.14),
Hot pressing the magnetic powder to obtain a molded body, and hot plastic working the molded body,
including,
A method for producing a rare earth magnet.   The method of claim 7, wherein x is 0.10 ≦ x ≦ 0.30.   9. A method according to claim 7 or 8, wherein z is 0.055 ≦ z ≦ 0.100.   The method according to claim 7, wherein r is 0.1 ≦ r ≦ 1.0.   The method according to claim 7, wherein the magnetic powder is obtained by a liquid quenching method.

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