JP2020113648A - Rare earth magnet, film, laminate, manufacturing method for rare earth magnet, motor, generator, and automobile - Google Patents

Abstract

To provide a rare earth magnet having excellent coercive force, a film, a laminate, a manufacturing method for a rare earth magnet, a motor, a generator, and an automobile.SOLUTION: A rare earth magnet has a main phase and a grain boundary phase arranged so as to cover at least a part of the main phase, and when R1 is at least one selected from the group consisting of La, Pr, Sm, Nd, Eu, Tb, and Lu, R2 is at least one selected from the group consisting of Y, Er, Tm, Ce, Dy, Ho, Yb, Gd, and Zr, T is at least one selected from the group consisting of Fe, Co, and Ni, and M is at least one selected from the group consisting of Cu, Ga, Zn, Al, Mg, Sn, Ge, Au, Si, Ca, and Ag, the total composition is represented by (R1pR21-p)xMyT100-x-y, and at least the main phase has a ThMn12 type crystal structure.SELECTED DRAWING: Figure 1

Description

The present invention relates to a rare earth magnet, a film, a laminated body, a method for manufacturing a rare earth magnet, a motor, a generator, and an automobile.

When R is a rare earth element, a rare earth magnet using a compound represented by R—Fe(iron)—B(boron) is used in motors for hybrid vehicles and electric vehicles, and has specific characteristics. Various attempts have been made to improve the above. Among them, for automobile motors, rare earth magnets added with heavy rare earths (for example, Dy (dysprosium)) have been studied so that desired characteristics can be exhibited even in a high temperature environment.

However, in recent years, in view of the fact that heavy rare earths are rare resources, there has been a demand for the development of rare earth magnets in which the amount of heavy rare earths used is as small as possible. Therefore, attention is focused on a rare earth magnet made of a compound having a “ThMn ₁₂ type” crystal structure that requires a small amount of a rare earth element.

On the other hand, the ThMn ₁₂ type crystal structure may be unstable, and in order to stabilize it, a method of substituting a part of the ThMn ₁₂ type crystal structure with an element such as Ti has been proposed. However, according to the above method, the rare earth magnet obtained may have insufficient magnetization.

Against this background, in Patent Document 1, it is possible to synthesize a single crystal of a compound represented by Sm(Fe _0.8 Co _0.2 ) ₁₂ , and the obtained single crystal has a saturation magnetization, It is described that the anisotropic magnetic field and the intrinsic magnetic properties such as the Curie temperature all have excellent properties exceeding Nd ₂ Fe ₁₄ B.

Y. Hirayama, et al., Scr. Mater. 138 (2017) 62-65.

The inventors of the present invention tried to make a magnet using the compound described in Non-Patent Document 1, and although the above compound has excellent intrinsic magnetic properties, when applied to a rare earth magnet, there is room for improvement in coercive force. I found that there is.
Therefore, an object of the present invention is to provide a rare earth magnet having an excellent coercive force. Moreover, this invention also makes it a subject to provide a film, a laminated body, the manufacturing method of a rare earth magnet, a motor, a generator, and a motor vehicle.

As a result of intensive studies to achieve the above object, the present inventors have found that the above object can be achieved by the following configuration.

[1] A rare earth magnet having a main phase and a grain boundary phase arranged to cover at least a part of the main phase, wherein R ¹ is La (lanthanum), Pr (praseodymium), Sm( Samarium), Nd (neodymium), Eu (europium), Tb (terbium), and at least one selected from the group consisting of Lu (lutetium), R ² is Y (yttrium), Er (erbium), Tm (Thulium), Ce (cerium), Dy (dysprosium), Ho (holmium), Yb (ytterbium), Gd (gadolinium), and Zr (zirconium), and at least one selected from the group consisting of Fe and T. At least one selected from the group consisting of (iron), Co (cobalt), and Ni (nickel), and M is Cu (copper), Ga (gallium), Zn (zinc), Al (aluminum), Mg. (Magnesium), Sn (tin), Ge (germanium), Au (gold), Si (silicon), Ca (calcium), and at least one selected from the group consisting of Ag (silver), and x is 100. /13 to 100/11, y is a number greater than 0 and 10 or less, and p is a number from 0.5 to 1, the overall composition is represented by the formula 1: (R ¹ _p R ² _{1- p)} is represented by _{x M y T 100-x-} y, it has a crystal structure of at least the main phase is ₁₂ type ThMn, the grain boundary phase, the line analysis profile obtained by energy dispersive X-ray analysis Based on the position P _{max at} which the content of the atomic unit of M in the specified rare earth magnet has a maximum value, the above content is the maximum value for the first time before and after the position P _max in the line analysis profile. A rare earth magnet, defined as the area between two positions P _{boundary that} is ½ of.
[2] The rare earth magnet according to [1], wherein the particle size of the main phase is 1 μm or less.
[3] The main phase is Al, Si, Ti (titanium), V (vanadium), Mo (molybdenum), Nb (niobium), Cr (chromium), Mn (manganese), C (carbon), B, Mg , Cu, Zn, and W (tungsten) are not substantially contained, the rare earth magnet according to [1] or [2].
[4] The rare earth magnet according to any one of [1] to [3], wherein the T is Fe and Co.
[5] The rare earth magnet according to any one of [1] to [4], wherein the M is at least one selected from the group consisting of Cu and Ga.
[6] The crystal orientation of the main phase and at least one selected from the group consisting of easy magnetization axes are preferentially oriented along a predetermined direction. [1] to [5] Rare earth magnets.
[7] A film containing the rare earth magnet according to any one of [1] to [6].
[8] The film according to [7], wherein at least one selected from the group consisting of the crystal orientation of the main phase and the easy axis of magnetization is preferentially oriented along the thickness direction.
[9] An underlayer and a rare earth magnet layer containing the rare earth magnet according to any one of [1] to [6] formed so as to be in contact with the underlayer, the underlayer being polycrystalline. A laminate having a structure and having crystal orientations preferentially oriented along the thickness direction of the underlayer.
[10] The laminate according to [8], wherein the crystal orientation of the main phase of the rare earth magnet layer is preferentially oriented along the thickness direction of the rare earth magnet layer.
[11] The laminated body according to [9] or [10], wherein the base layer is a base layer with a support layer further having a support.
[12] The laminated body according to [11], wherein the base layer with the support layer further has a buffer layer between the base layer and the support.
[13] The laminate according to any one of [9] to [12], further including a cap layer.
[14] A polycrystalline phase having a ThMn ₁₂ type crystal structure, wherein R ¹ is at least one selected from the group consisting of La, Pr, Sm, Nd, Eu, Tb, and Lu, and R ² is at least one selected from the group consisting of Y, Er, Tm, Ce, Dy, Ho, Yb, Gd, and Zr, and T is at least selected from the group consisting of Fe, Co, and Ni. when the one, and the number of x 100 / 13-100 / 11, and the number of 0.5 to p, equation _^2: Table with _{^{(R 1 p R 2 1-}} p) X T 100-X Step 1 of forming a rare earth magnet precursor containing a compound as a main component, and Cu, Ga, Zn, Al, Mg, Sn, Ge, Au so as to cover at least a part of the surface of the rare earth magnet precursor. A nonferromagnetic element-containing layer containing at least one element M selected from the group consisting of Si, Ca, and Ag, and forming a rare earth magnet precursor with a nonferromagnetic element-containing layer 2 And heating the rare earth magnet precursor with a non-ferromagnetic element-containing layer to diffuse the element M in the rare earth magnet precursor to obtain the rare earth magnet according to any one of [1] to [6]. And a method for manufacturing a rare earth magnet having:
[15] The step 1 is a step of forming a rare earth magnet precursor layer containing a rare earth magnet precursor on the underlayer, the underlayer has a polycrystalline structure, and the crystal orientation is the underlayer. The method for producing a rare earth magnet according to [13], which is preferentially oriented along the thickness direction of the.
[16] A motor having the rare earth magnet according to any one of [1] to [6].
[17] An automobile having the motor according to [16].
[18] A generator having the rare earth magnet according to any one of [1] to [6].
[19] An automobile having the generator according to [18].

According to the present invention, a rare earth magnet having an excellent coercive force can be provided. Further, according to the present invention, a film, a laminate, a method for manufacturing a rare earth magnet, a motor, a generator, and an automobile can be provided.

It is a schematic diagram of the line analysis profile obtained by the energy dispersive X-ray analysis method for the rare earth magnet according to the embodiment of the present invention. It is a schematic diagram of the laminated body which concerns on embodiment of this invention. It is a schematic diagram of the motor which concerns on embodiment of this invention. It is a schematic diagram of the generator which concerns on embodiment of this invention. It is a conceptual diagram which shows the electric power generation of the vehicle which concerns on embodiment of this invention, electric storage, and a drive mechanism. 3 is an XRD (X-ray diffusion) pattern measured by adjusting the out of plane of the Sm(Fe _0.8 Co _0.2 ) ₁₂ anisotropic polycrystalline film and the χ axis. 3 is a cross-sectional TEM (Transmission Electron Microscope) image of an Sm(Fe _0.8 Co _0.2 ) ₁₂ anisotropic polycrystalline film. It is a plane TEM image of Sm _{(Fe 0.8 Co 0.2) 12} anisotropic polycrystalline film. 3 is a magnetization curve of out of plane and in plane of Sm(Fe _0.8 Co _0.2 ) ₁₂ anisotropic polycrystalline film. 3 is a magnetization curve of a Sm(Fe _0.8 Co _0.2 ) ₁₂ anisotropic polycrystalline film after demagnetizing field correction. Sm _{(Fe 0.8 Co 0.2)} is a (BH) -H curve of ₁₂ anisotropic polycrystalline film. Is an XRD pattern of the rare earth magnet according to an embodiment of the present invention (Cu-Ga diffusion treated _{Sm (Fe 0.8 Co 0.2) 12} anisotropic polycrystalline film). The in-plane TEM images of Cu-Ga diffusion treated _{Sm (Fe 0.8 Co 0.2) 12} anisotropic polycrystalline film. Plane ADF-STEM rare earth magnet according to an embodiment of the present invention (Cu-Ga diffusion treated _{Sm (Fe 0.8 Co 0.2) 12} anisotropic polycrystalline film) (Annular Dark Field ScanningTransmission Electron Microscope ) image Is. Is EDS (Energy dispersive X-ray spectrometry ) mapping images of a rare earth magnet according to the embodiment (Cu-Ga diffusion treated _{Sm (Fe 0.8 Co 0.2) 12} anisotropic polycrystalline film) of the present invention. FIG. 16 is an (in-plane) EDS line scan profile taken along the line AB of FIG. 15. It is an EDS line scan profile which extracted only the content of the element M in FIG. It is EDS mapping image of the cross section (Menjika) of the rare-earth magnet according to an embodiment of the present invention (Cu-Ga diffusion treated _{Sm (Fe 0.8 Co 0.2) 12} anisotropic polycrystalline film). 19 is an EDS line scan profile along the line CD of FIG. 18. It is an EDS line scan profile which extracted only the content of the element M in FIG. 4 is a magnetization curve of a rare earth magnet (Sm(Fe _0.8 Co _0.2 ) ₁₂ anisotropic polycrystalline film subjected to Cu—Ga diffusion treatment) according to an embodiment of the present invention. Diffusion process is a comparison of the demagnetization curve of the front and rear _{Sm (Fe 0.8 Co 0.2) 12} anisotropic polycrystalline film. It is the heat treatment temperature dependence of the coercive force of the Sm(Fe _0.8 Co _0.2 ) ₁₂ anisotropic polycrystalline film in which various non-ferromagnetic elements are diffused. It is a recoil curve in the demagnetization process before and after Cu-Ga diffusion. It is the temperature dependence of the coercive force of the Sm(Fe _0.8 Co _0.2 ) ₁₂ anisotropic polycrystalline film before and after the diffusion treatment.

Hereinafter, the present invention will be described in detail.
The description of the constituent elements described below may be made based on a typical embodiment of the present invention, but the present invention is not limited to such an embodiment.
In addition, in this specification, the numerical range represented by "-" means the range which contains the numerical value described before and behind "-" as a lower limit and an upper limit unless there is particular notice.

[Rare earth magnet]
A rare earth magnet according to an embodiment of the present invention is a rare earth magnet having a main phase and a grain boundary phase arranged so as to cover at least a part of the main phase, wherein R ¹ is La, Pr, At least one selected from the group consisting of Sm, Nd, Eu, Tb, and Lu, and R ² is selected from the group consisting of Y, Er, Tm, Ce, Dy, Ho, Yb, Gd, and Zr. At least one selected from the group consisting of Fe, Co, and Ni, and M is Cu, Ga, Zn, Al, Mg, Sn, Ge, Au, Si, Ca. , And at least one selected from the group consisting of Ag, x is a number from 100/13 to 100/11, y is a number exceeding 0 and 10 or less, and p is a number from 0.5 to 1. when a, the entire composition, wherein _^1: is represented by _{^{(R 1 p R 2 1-}} p) x M y T 100-x-y, at least the main phase has a crystal structure of _12-inch ThMn, the The grain boundary phase is the above line based on the position P _{max at} which the content of the atomic unit of M in the rare earth magnet specified by the line analysis profile obtained by the energy dispersive X-ray analysis method has a maximum value. It is a rare earth magnet defined as a region between two positions P _{boundary at which} the content becomes 1/2 of the maximum value for the first time before and after the position P _max in the analysis profile.
Note that x, y, and p are all based on the number of atoms.
Hereinafter, the configuration of the rare earth magnet according to the embodiment of the present invention will be described in detail.

[Overall composition]
Overall composition of the rare earth magnet according to an embodiment of the present invention ^is represented by _{^{(R 1 p R 2 1-}} p) x M y T 100-x-y.
In the present specification, the “total composition” is obtained by the energy dispersive X-ray analysis method, and the measuring method is as described in the examples. Specifically, the overall composition is specified by observing the cross section of the rare earth magnet by ADF-STEM and analyzing the average of the elemental composition in the same field of view as the obtained image by energy dispersive X-ray analysis. To do.

・R ¹ in the overall composition
In Formula 1, R ¹ is at least one selected from the group consisting of La, Pr, Sm, Nd, Eu, Tb, and Lu (hereinafter, also referred to as “specific rare earth element”). As the specific rare earth element for R ¹ , one type may be used alone, or two or more types may be used in combination.
Among them, R ¹ is more preferably at least one selected from the group consisting of Sm, La, Pr, Nd, and Lu, in that a rare earth magnet having a more excellent effect of the present invention can be obtained. At least one selected from the group consisting of Sm, La, and Lu is more preferable, and Sm is particularly preferable.

When the specific rare earth element is used in combination, it is preferable that at least one selected from the group consisting of Sm, La, Tb, and Lu is contained, and selected from the group consisting of Sm, La, and Lu. It is more preferable to contain at least one of the above compounds, and it is particularly preferable to contain Sm.

Among the specific rare earth elements, Sm has a positive Stevens factor and is presumed to form a ferromagnetic bond with an atom represented by T described later in the ground state, and when R ¹ contains Sm, a rare earth magnet obtained Has a superior effect of the present invention.

The Stevens factor is a physical quantity related to the charge density (shape) of 4f electrons in the inner shell of a rare earth element. If this is negative, the shape is contracted with respect to the axis of symmetry, and if it is positive, the shape extends from spherical symmetry. The 4f electron cloud receives a crystal field from surrounding ions to determine its stable direction, and thus the shape of electron transport determines the direction of magnetic anisotropy.

Among the specific rare earth elements, La and Lu are elements that do not have magnetism by themselves, but the rare earth magnet obtained by R ¹ containing the above has excellent stability.

Among the specific rare earth elements, Nd and Pr have a negative second-order Stevens factor, but since they form a ferromagnetic coupling with T described later, the magnetization is further increased, and as a result, a better book. A rare earth magnet having the effects of the invention can be obtained.

・R ² in the overall composition
In Formula 1, R ² is at least one selected from the group consisting of Y, Er, Tm, Ce, Dy, Ho, Yb, Gd, and Zr (hereinafter, also referred to as “specific element”). .. The specific element of R ² may be used alone or in combination of two or more.
Among them, R ² is preferably at least one selected from the group consisting of Y, Ce, Gd, and Zr in that a rare earth magnet having a more excellent effect of the present invention can be obtained.

Of the specific elements, Y and Ce (among them, Ce(IV) is preferable) are elements that do not have magnetism by themselves, but a rare earth magnet obtained by containing R ² described above. Has excellent stability.

Among the specific elements, Gd and Zr have a function of further improving the stability of the obtained rare earth magnet, and particularly when R ¹ contains Sm, the effect is more remarkable.

In Formula 1, x is not particularly limited as long as it is a number from 100/13 to 100/11. The p is not particularly limited as long as it is a number of 0.5 to 1. When two or more elements are used as R ¹ , the total content thereof is preferably within the range of p. When two or more elements are used as R ² , the total content thereof is preferably within the range of 1-p above.

・T in formula 1
In Formula 1, T is at least one selected from the group consisting of Fe, Co, and Ni. These are classified as iron group elements and have common properties in that they exhibit ferromagnetism at room temperature and atmospheric pressure. Therefore, Fe, Co, and Ni as T can be substituted with each other. As T, the above iron group elements may be used alone or in combination of two or more kinds.

As T, at least one selected from the group consisting of Fe and Co is preferable in terms of obtaining a rare earth magnet having more excellent effects of the present invention, and it is preferable to use Fe and Co in combination. .. When Co is contained as T, the magnetization of the rare earth magnet is further improved and the Curie temperature is further increased.
That is, T is preferably Fe and Co. That is, the formula 1, ^{_{formula: (R 1 p R 2 1}} -p) x M y (Fe q Co 1-q) is preferably represented by _100-x-y. At this time, q is a number of 0.5 to 0.9.
In that the rare-earth magnet having the effect of the present invention over the Among them obtained, as the Formula 1, ^{_{Formula: (Sm p R 2 1-}} p) x M y (Fe q Co 1-q) 100-x- More preferably, it is represented by _y .

・M in the overall composition
In Formula 1, M is at least one element selected from the group consisting of Cu, Ga, Zn, Al, Mg, Sn, Ge, Au, Si, Ca, and Ag.
In addition, as for M, one of the above elements may be used alone, or two or more thereof may be used in combination.

Each of M is a non-ferromagnetic element.
Among them, Cu (1084°C), Zn (419°C), Al (660°C), Mg (650°C), Ge (938°C), Au (1064°C), Si (1414°C), Ca (842°C) , And at least one refractory element M _high selected from the group consisting of Ag (961° C.) has a lower affinity for the main phase described later, and is more likely to be unevenly distributed in the grain boundary phase, and as a result, A rare earth magnet having an excellent coercive force is easily obtained.
In the present specification, the high melting point element M _high means an element having a melting point of 400° C. or higher and an element other than the rare earth element.
Further, in the above description, the value in parentheses is the melting point of each simple substance.

Moreover, when at least one low melting point element M _low selected from the group consisting of Ga (29° C.) and Sn (231° C.) in M is contained, the rare earth magnet having the excellent effect of the present invention is obtained. Can be obtained more easily by the production method described below.
In the present specification, the low melting point element M _low means a single element having a melting point of lower than 400° C. and an element other than the rare earth element.
Further, in the above description, the value in parentheses is the melting point of each simple substance.

When M is composed of two or more of the above elements, it is preferable to contain one or more of each of M _high and M _low . Among them, when considering a combination of a plurality of Ms, a lower eutectic temperature is obtained. Combinations capable of forming alloys are preferred.

More specifically, M is at least one selected from the group consisting of Cu, Zn, Al, Mg, Sn, and Ga in that a rare earth magnet having the excellent effect of the present invention can be obtained. Is preferably contained, and when two or more kinds of M are contained, at least one of Cu and Zn is contained and selected from the group consisting of La, Al, Mg, Sn, and Ga. It is preferable to further contain at least one of Above all, it is more preferable to contain at least one selected from the group consisting of Cu and Ga, and it is further preferable to contain Cu and Ga.

[Main phase]
The rare earth magnet according to the embodiment of the present invention has the main composition described above and has the main phase and the grain boundary phase arranged to cover at least a part of the main phase. The grain boundary phase may be arranged so as to cover at least a part of the main phase, but may be arranged so as to cover the whole main phase.

In the rare earth magnet according to the embodiment of the present invention, at least the main phase has a ThMn ₁₂ type crystal structure. That is, the present rare earth magnet has a form in which a grain boundary phase exists in at least a part of grain boundaries between crystal grains having a ThMn ₁₂ type crystal structure.
At this time, the grain size of the crystal grain is not particularly limited, but in terms of obtaining a rare earth magnet having a more excellent coercive force, it is preferably 1 μm or less, more preferably 500 nm or less, further preferably 200 nm or less, and 100 nm or less. Particularly preferred, and 50 nm or less is most preferred. The lower limit is not particularly limited, but generally 10 nm or more is preferable.

In the present specification, the “particle size” is a value obtained by measuring the length t in the longitudinal direction of 10 main phases in the field of view in a bright field image of a transmission electron microscope and arithmetically averaging the measured values. means. When the shape of the main phase on the image (typically, the cross-sectional shape) is elliptical, the length of its major axis is t. When the cross section of the main phase is quadrangular, the length of the longer diagonal line is t.

Among them, the main phase is Al, Si, Ti, V, Mo, Nb, Cr, Mn, C, B, Mg, Cu, Zn, in that a rare earth magnet having a more excellent effect of the present invention can be obtained. Further, it is preferable that substantially none of W (hereinafter, also referred to as “excluded element”) is contained. A rare earth magnet that does not substantially contain the above in the main phase has a better coercive force.

In the present specification, “substantially free of inclusion” means that the content of excluded elements is 0.01 atom% of all the atoms when contained in the main phase is analyzed by energy dispersive X-ray analysis. It means less than or equal to 0.001, preferably less than or equal to 0.001 atomic %, and more preferably less than or equal to 0.0001 atomic %,
When the main phase contains two or more types of exclusion elements, the total of the two or more types of exclusion elements is preferably within the above numerical range.

[Grain boundary phase]
The grain boundary phase is a phase arranged so as to cover at least a part of the main phase, in other words, the grain boundary phase is a phase existing around the main phase.
The grain boundary phase is a position P _max (hereinafter, referred to as “maximum position”) at which the content of the element M in the atomic number unit in the rare earth magnet specified by the line analysis profile obtained by the energy dispersive X-ray analysis method has a maximum value. (Also referred to as a “boundary position”), before and after the maximum position in the line analysis profile, the two positions P _boundary (hereinafter, also referred to as “boundary position”) in which the content becomes ½ of the maximum value for the first time. Is defined as the area between

FIG. 1 is a schematic diagram of a line analysis profile obtained by an energy dispersive X-ray analysis method for a rare earth magnet according to an embodiment of the present invention. In the line analysis profile of FIG. 1, the horizontal axis represents the position (distance, unit: nm), and the vertical axis represents the content (at. %) of the element M based on the number of atoms. The procedure for identifying the grain boundary phase will be described with reference to FIG.

(1. Position P _max- Specification of maximum position)
First, the maximum position is specified from the line analysis profile. In FIG. 1, the positions (values on the horizontal axis) in Max _{1 to} Max ₄ are candidates, but the maximum value in the present specification means a value larger than the content of the element M in the overall composition already described. In FIG. 1, Max ₁ and Max ₂ have maximum values, and Max ₃ and Max ₄ do not have maximum values.
The maximum positions are specified as the positions P _max -1 and P _max -2 that give the maximum values Max ₁ and Max ₂ .

(2.2 Two Positions _Pboundary- Specification of Boundary Position)
Next, two boundary positions sandwiching the maximum position are specified based on the maximum position. The maximum position P _max -1 in FIG. 1 will be described as an example. First, the content (maximum value: Max ₁ ) of the element M based on the number of atoms at the maximum position P _max −1 is specified by the line analysis profile, and half the amount thereof is specified. Next, from the line analysis profile, the boundary positions before and after P _max −1, that is, in the positive direction and the negative direction of the horizontal axis, where the content of the element M becomes the above-mentioned 1/2 amount for the first time are specified. The boundary position has one point in each of the positive direction and the negative direction of the horizontal axis based on the maximum position. In Figure _{1, P boundary -1, and, P boundary} -2 corresponds to each boundary position.

(3. Specification of grain boundary phase)
From the above, the grain boundary phase is specified. The grain boundary phase is a region between the two boundary positions specified in Procedure 2, and is defined as a region including the maximum position. In Figure _1, the region of _{P boundary} -1~P _boundary -2 is defined as a grain boundary phase, the boundary position _{P boundary -1, and, P boundary} -2 itself included in the grain boundary phase.
Similar to the _above, with respect to _{P max} -2, grain boundary _phase, P _{boundary -3~P boundary} -4 it is defined.

The region defined as above is the grain boundary phase, and the main phase in this specification means a region other than the grain boundary phase. In Figure _1, the region of _{P boundary} -2~P _{boundary -3,} the region of _{to P boundary} -1, and _the area of the _{P boundary} -4 to correspond to the main phase. The boundary position itself is not included in the main phase.

The specific content (atomic %) of M in the grain boundary phase can be appropriately adjusted, but is preferably 3.0 atomic% or more when the total number of atoms in the grain boundary phase is 100 atomic %. It is more preferably 4.0 atom% or more, further preferably 5.0 atom% or more, and particularly preferably 6.0 atom% or more.
The upper limit of the M content in the grain boundary phase is not particularly limited, but is generally preferably 30 atomic% or less.

The thickness of the grain boundary phase is not particularly limited, but the interval between the two boundary positions defined by the above method is preferably 1 to 5 nm, more preferably 2 to 5 nm.
When the thickness of the grain boundary phase is within the above numerical range, the rare earth magnet has more excellent effects of the present invention.

The grain boundary phase may have a crystal structure, or may not have a crystal structure (amorphous).

The grain boundary phase may contain other elements as long as it contains M. Examples of the other element include the elements described as R ¹ , R ² and T in the formula 1 which have already been described.
When the grain boundary phase contains R ¹ , the content of R ¹ is not particularly limited, but is generally preferably 100/13 to 100/11 atom% with respect to all the atoms in the grain boundary phase.
Further, when the grain boundary phase contains R ² , the content of R ² is not particularly limited, but it is preferably within the above numerical range in total with R ¹ . At this time, the content ratio of R ¹ and R ² is preferably the same as that of the main phase.
When the grain boundary phase contains T, the content of T is not particularly limited, but is generally preferably 30 to 70 atom% with respect to all the atoms in the grain boundary phase.

Further, the grain boundary phase may contain other elements than the above. Examples of the other element include at least one selected from the group consisting of Na (sodium), Rb (rubidium), In (indium), Cs (cesium), and Hg (mercury). Each of the above elements has a low melting point of a simple substance, and it is easy to form an alloy having a lower eutectic temperature with the element of M. As a result, the content of M in the main phase is smaller and the content of M in the grain boundary phase is smaller. It is easy to obtain a rare earth magnet having a higher content of and having an excellent coercive force.

The main phase of the rare earth magnet according to the embodiment of the present invention has the ThMn ₁₂ type crystal structure as described above, but the crystal orientation of the main phase and the orientation state of the easy axis of magnetization are not particularly limited.
Above all, at least one selected from the group consisting of the crystal orientation and the easy axis of magnetization is preferentially oriented along a predetermined direction in that the maximum energy product (BH)max tends to be larger. preferable. In the present specification, a rare earth magnet in which at least one selected from the group consisting of crystal orientation and easy axis of magnetization is preferentially oriented along a predetermined direction is also referred to as a rare earth anisotropic magnet.
That is, the rare earth magnet according to the embodiment of the present invention is preferably a rare earth anisotropic magnet.

For example, Sm(Fe _0.8 Co _0.2 ) ₁₂ has a better maximum energy product (BH)max when (001) is the easy axis of magnetization and the above is preferentially oriented in a predetermined direction. A rare earth (anisotropic) magnet having is obtained.
In the present specification, the “preferred orientation” is selected from a group consisting of a predetermined crystal orientation and an easy axis of magnetization in in-plane measurement of XRD (X-ray diffusion) or out-of-plane measurement. It means that peaks other than the peaks derived from at least one of the above are not substantially detected.
In addition, substantially not detected, the predetermined crystal orientation, and, with respect to the sum of the peak intensity of the peak derived from at least one selected from the group consisting of easy magnetization axis, the sum of the peak intensity of the other peak, It means 1% or less, preferably 0.1% or less, more preferably 0.01% or less, and further preferably not detecting other peaks.

The rare earth magnet according to the embodiment of the present invention is not particularly limited in its form and the like as long as it has the above characteristics. The form of the rare earth magnet may be, for example, a particle shape, a flat plate shape, or a three-dimensional shape having a curved surface.
Further, the rare earth magnet may have a flat plate shape (film).

[Uses of rare earth magnets]
The rare earth magnet according to the embodiment of the present invention has more excellent coercive force than the Nd-Fe-B based magnet, and in particular, the temperature coefficient of the coercive force is smaller, so that it is more excellent in high temperature characteristics. The rare earth magnet according to the embodiment of the present invention can be preferably used for automobile motors, energy-saving electric appliances, etc. as a high-performance permanent magnet that requires a higher coercive force under a high temperature environment.
[Rare earth magnet manufacturing method]
The method for manufacturing the rare earth magnet according to the embodiment of the present invention is not particularly limited, and a known method for manufacturing a rare earth magnet can be applied. As a known method for producing a rare earth magnet, for example, a rare earth magnet precursor (for example, Sm(Fe _0.8 Co _0.2 ) ₁₂ described later is prepared, and the rare earth magnet precursor is pulverized to prepare a powder. , A powder containing a non-ferromagnetic element (for example, Cu) for forming a grain boundary phase is prepared, the above-mentioned two kinds of powders are mixed and molded to obtain a molded body, and the molded body is required. Accordingly, it can be manufactured by heating and/or pressurizing under the application of a magnetic field.
Examples of the manufacturing method as described above include, for example, JP-A-2017-50396, the contents of which are incorporated herein.

Among them, the method for producing a rare earth magnet is preferably a method for producing a rare earth magnet, which has the following steps 1 to 3 in that a rare earth magnet having a more excellent effect of the present invention can be obtained.

Step 1 is a polycrystalline phase having a ThMn ₁₂ type crystal structure, wherein R ¹ is at least one selected from the group consisting of La, Pr, Sm, Nd, Eu, Tb, and Lu, R ² is at least one selected from the group consisting of Y, Er, Tm, Ce, Dy, Ho, Yb, Gd, and Zr, and T is selected from the group consisting of Fe, Co, and Ni. When at least one kind is used, x is a number of 100/13 to 100/11, and p is a number of 0.5 to 1,
Formula ^{_{2: (R 1 p R 2}} 1-p) X T 100-X
This is a step of forming a rare earth magnet precursor containing a compound represented by as a main component.

Step 2 is at least selected from the group consisting of Cu, Ga, Zn, Al, Mg, Sn, Ge, Au, Si, Ca, and Ag so as to cover at least a part of the surface of the rare earth magnet precursor. This is a step of arranging a non-ferromagnetic element-containing layer containing one kind of element M to form a rare earth magnet precursor with a non-ferromagnetic element-containing layer.

Step 3 is a step of heating the rare earth magnet precursor with a non-ferromagnetic element-containing layer and diffusing the element M in the rare earth magnet precursor to obtain a rare earth magnet. Below, each process is explained in full detail.

(Process 1)
Step 1 is a step of forming a rare earth magnet precursor whose main component is a compound having a predetermined structure. The rare earth magnet precursor has a ThMn ₁₂ type crystal structure and is a polycrystalline phase in which a large number of crystal grains are aggregated.
It is preferable that the rare earth magnet precursor does not substantially contain the above-mentioned exclusion element, which means that it is 0.01 atom% or less of all the atoms, and 0.001 atom% or less is more preferable. It is more preferably 0.0001 atomic% or less.

The method for forming the rare earth magnet precursor is not particularly limited, and a sintering method, an ultra-rapid cooling solidification method, a vapor deposition method, an HDDR (Hydrogenation Decomposition Decombination) method and the like can be applied. Above all, it is preferable to form the rare earth magnet precursor (layer) on the support by the sputtering method because it can be more easily formed.
The form of forming the rare earth magnet precursor layer by the sputtering method will be described in detail.

The support is not particularly limited, and a known support can be used. Among them, as the support, silicon, low-temperature fired ceramics, Al ₂ O ₃ , LiTaO ₃ , LiNbO, quartz, SiC, GaAs, GaN, and , Glass, and the like.
Further, the support may be doped with another element (for example, arsenic and/or phosphorus-doped silicon), or may be a laminate having a plurality of layers (for example, , Silicon with thermal oxide).

Is not particularly restricted but includes pressure in the chamber of the deposition apparatus in which sputtering is performed in view of reducing more the contamination of unintended ingredients in the rare-earth magnet precursor obtained is preferably not more than 10 -6 ^Pa, 10 ^{- 8} Pa or less is more preferable. Further, it is preferable to clean the surface of the support before laminating the rare earth magnet precursor on the support. The method of cleaning the surface of the support is not particularly limited, and examples thereof include a method of sputtering the support itself. According to the above, it is possible to remove the oxide film of the support formed on the support, the organic matter and the like.

The method of sputtering is not particularly limited, but a magnetron sputtering method that enables sputtering in a lower pressure Ar atmosphere is preferable. Here, by adjusting the thickness of the target material, the reduction of the leakage flux of magnetron sputtering can be further suppressed and the sputtering can be made easier. The power source for sputtering can be either DC or RF, and can be appropriately selected according to the target material.

The heating temperature of the support for the rare earth magnet precursor, the film formation rate, and the film formation time are not particularly limited, and may be appropriately adjusted according to the required thickness of the rare earth magnet precursor. The film formation rate can be adjusted by the sputtering power and/or the time.

In addition to the above, the step 1 may further include a step of forming a buffer layer and/or an underlayer on the support before forming the rare earth magnet precursor.

The underlayer is a layer formed between the support and the rare earth magnet precursor, and is preferably formed so as to be in direct contact with the rare earth magnet precursor.
That is, the rare earth magnet precursor is preferably formed on the base layer formed on the support.
Forming the rare earth magnet precursor on the underlayer is preferable in that the crystal orientation of the rare earth magnet precursor can be controlled.

The material of the underlayer is not particularly limited, but a form that can reduce lattice defects due to lattice mismatch with a rare earth magnet precursor to be formed later and improve crystallinity is preferable. That is, the material of the underlayer is more preferably the same as the lattice constant of the rare earth magnet precursor.

The material component of the underlayer is not particularly limited and may be appropriately selected depending on the rare earth magnet precursor to be formed later, but for example, crystals with higher crystallinity and/or higher orientation It is preferable that MgO, V, and the like are contained from the viewpoint of obtaining
The material of the underlayer preferably contains one or more of the above material components, but may contain two or more. In that case, it may be a solid solution, a eutectic (eutectic mixture), an intermetallic compound, or a mixture thereof, or may be a laminate. That is, the underlayer may be a laminate of a plurality of layers.

The material of the underlayer is preferably polycrystalline. By using the underlayer which is polycrystalline, the rare earth magnet precursor to be formed later can easily form a polycrystalline phase, and as a result, a rare earth magnet having more excellent effects of the present invention can be obtained.

The method for forming the underlayer is not particularly limited, and a known method can be applied. Among them, the method similar to the method of forming the rare earth magnet precursor (layer) described above is preferable in that the underlayer can be formed more easily.

The buffer layer is typically a layer disposed between the support and the underlayer described above. The material component of the buffer layer is not particularly limited, but it is generally preferable to use a material having high thermal conductivity, and specific examples thereof include amorphous NiTa.
The method for forming the buffer layer is not particularly limited, but the same method as that for the rare earth magnet precursor described above can be applied.

(Process 2)
Step 2 is selected from the group consisting of Cu, Ga, Zn, Al, Mg, Sn, Ge, Au, Si, Ca, and Ag so as to cover at least a part of the surface of the rare earth magnet precursor. It is a step of disposing a non-ferromagnetic element-containing layer containing at least one element M and forming a rare earth magnet precursor with a non-ferromagnetic element-containing layer.

Step 2 is typically a step of forming the non-ferromagnetic element-containing layer so as to cover at least a part of the surface of the rare earth magnet precursor (layer) formed on the support.
The non-ferromagnetic element-containing layer is preferably formed so as to cover 51% or more of the surface area of the rare earth magnet precursor, more preferably formed so as to cover 80% or more of the surface area of the rare earth magnet precursor. More preferably, it is formed so as to cover the whole.

The non-ferromagnetic element contained in the non-ferromagnetic element-containing layer is not particularly limited in form and structure as long as it contains the element M, and may be the above M alone or a plurality of M solid solutions, It may be a eutectic (eutectic mixture), an intermetallic compound, or a mixture thereof.

The form of M is the same as that described as the component of the rare earth magnet, but if M contains a high melting point element, it has a lower affinity with the rare earth magnet precursor (more difficult to form a solid solution) and will be described later. In step 3, M is less likely to diffuse into the crystal of the rare earth magnet precursor, and as a result, a rare earth magnet having more excellent coercive force is easily obtained.

Further, when M contains a low melting point element of M, even if the M is treated at a temperature at which the change in crystal structure (eg, melting) of the rare earth magnet precursor does not easily occur in step 3 described later, M is a rare earth magnet. Since it is easy to diffuse due to the grain boundaries of the precursor, it is easy to obtain a rare earth magnet having a better coercive force as a result.

Further, when using two or more kinds of the above M, it is preferable to contain one or more kinds of each of the high melting point element M _high and the low melting point element M _low described above. Among them, when considering the combination of M, Combinations capable of forming low eutectic temperature alloys are preferred.

It is preferable to use at least one selected from the group consisting of Cu, Zn, Al, Mg, Sn, and Ga as M in that a rare earth magnet having more excellent effects of the present invention can be obtained. As M, at least one of Cu and Zn is preferably used in combination with at least one selected from the group consisting of Al, Mg, Sn, and Ga. Among them, as M, it is preferable to use at least one selected from the group consisting of Cu and Ga, and it is preferable to use Cu and Ga.

When two or more kinds of non-ferromagnetic elements are used as M, the above-mentioned two kinds of non-ferromagnetic elements may be laminated on the rare earth magnet precursor. That is, the non-ferromagnetic element-containing layer may be a laminated body.

The method of forming the non-ferromagnetic element-containing layer is not particularly limited, but, for example, the same method as the method of forming the rare earth magnet precursor described above can be applied.

(Process 3)
In step 3, the rare-earth magnet precursor layer with the non-ferromagnetic element-containing layer is heated to diffuse the non-ferromagnetic element into the rare-earth magnet precursor to obtain a rare-earth magnet. Sometimes called "treatment").

The heating method is not particularly limited, and a known method can be applied.
The heating temperature is not particularly limited, but is generally preferably 250 to 450°C, more preferably 350 to 450°C.
The heating time is not particularly limited, but is generally preferably 0.5 to 3 hours, more preferably 0.5 to 1 hour.
The atmosphere for heating is not particularly limited, but an inert gas atmosphere is generally preferable, and examples of the inert gas include Ar (argon).

By this step, the non-ferromagnetic element M diffuses into the rare earth magnet precursor by using the crystal grain boundaries of the rare earth magnet precursor as one of diffusion paths. As a result, a main phase and a grain boundary phase are formed, and a rare earth magnet having excellent coercive force is obtained.

The method for manufacturing a rare earth magnet according to the embodiment of the present invention may have another step other than the above steps within a range in which the effect of the present invention is exhibited. Another step is, for example, a cap layer forming step.

The cap layer is a layer formed for the purpose of protecting the rare earth magnet and/or preventing modification (for example, oxidation) of the rare earth magnet.
Therefore, the method for manufacturing a rare earth magnet according to the embodiment of the present invention preferably has a cap layer forming step after step 3.

The material component of the cap layer is not particularly limited, but the same material as the underlayer described above can be used. The method for forming the cap layer is not particularly limited, but the same method as that for the rare earth magnet precursor described above can be applied.

[film]
The film according to the embodiment of the present invention is a film containing the rare earth magnet described above.
Although the content of the rare earth magnet in the film according to the embodiment of the present invention is not particularly limited, it is generally preferably 50% by volume or more, more preferably 60% by volume or more, further preferably 70% by volume or more, and 80% by volume. The above is particularly preferable.

The film containing the rare earth magnet according to the embodiment of the present invention may contain other components as long as the effects of the present invention are exhibited, as long as the rare earth magnet described above is contained. Examples of the other component include a binder and the like.
The binder is not particularly limited, and known materials can be used, and inorganic materials, organic materials, and composite materials thereof can be used. Examples of known binders include epoxy resins.

Membranes according to embodiments of the present invention, to the extent that the effect of the present invention may contain other components, wherein 1 Oite R ¹ Examples of other ^components, R 2, ^{T and,} Examples thereof include compounds containing at least one of the elements described as M.

The main phase of the rare earth magnet in the film is a polycrystalline phase having a ThMn ₁₂ type crystal structure as described above, but at least one selected from the group consisting of the crystal orientation of the main phase and the easy axis of magnetization. The orientation state of is not particularly limited.
Among them, it is preferable that at least one selected from the group consisting of the crystal orientation and the easy magnetization axis is preferentially oriented along the thickness direction from the viewpoint that the maximum energy product (BH)max tends to be larger. ..
That is, the film is preferably a film containing a rare earth (anisotropic) magnet in which at least one selected from the group consisting of the crystal orientation and the easy axis of magnetization along the thickness direction is preferentially oriented.

[Laminate]
A laminate according to an embodiment of the present invention includes an underlayer and a rare earth magnet layer containing the rare earth magnet described above, which is formed so as to be in contact with the underlayer, and the underlayer has a polycrystalline structure. And a crystal orientation is preferentially oriented along the thickness direction of the underlayer.

This laminated body will be described with reference to FIG. The laminated body 10 has, in order from the cap layer 11, a rare earth magnet layer 12, an underlayer 15 composed of a first underlayer 13 and a second underlayer 14, a buffer layer 16, and a support 17.
The laminated body 10 includes the cap layer 11, the buffer layer 16, and the support 17, but the laminated body may include the underlayer 15 and the rare earth magnet layer 12.
The underlayer 15 in the laminate 10 is a laminate of the first underlayer 13 and the second underlayer 14, but the present laminate is not limited to the above, and the underlayer is a single layer. May be.

The form of the rare earth magnet layer is not particularly limited as long as it contains the rare earth magnet. However, for example, the film is preferably the above film, and the preferred form is also the same. Further, the configurations of the other layers are the same as those described in the method for manufacturing the rare earth magnet, and the preferred forms are also the same.

Since the rare earth magnet according to the embodiment of the present invention has an excellent coercive force, it is applicable to the fields of MEMS (Micro Electro Mechanical Systems), energy fields such as energy harvesting (environmental power generation), and medical devices.

[motor]
A motor according to an embodiment of the present invention is a motor including the rare earth magnet. FIG. 3 shows a permanent magnet motor 20 as a motor according to the embodiment of the present invention. The permanent magnet motor 20 has a stator 21 and a rotor 24 rotatably arranged in the stator 21. The rotor 24 has a core material 22 and a plurality of rare earth magnets 23 arranged in the core material 22.

Although FIG. 3 shows a permanent magnet motor, the motor according to the embodiment of the present invention is not limited to the above, and can be applied to a variable magnetic flux motor or the like.

[Generator]
A generator according to an embodiment of the present invention is a generator including the rare earth magnet. FIG. 4 shows a generator according to the embodiment of the present invention.
The generator 30 has a stator 31 having the rare earth magnet and a rotatably provided rotor 32. The rotor 32 is arranged inside the stator 31, and the rotor 32 is connected to the turbine 33 by a shaft 34. The turbine 33 is rotated by, for example, a fluid supplied from the outside, and the electromotive force generated by the rotation is taken out as the output of the generator 30. Note that the generator 30 may have other known members such as a phase-separating bus bar, a main transformer, and a brush for removing static electricity.
Further, the rotation of the turbine 33 is transmitted to the rotor 32 of the generator 30, but the generator according to the embodiment of the present invention is not limited to the above, and regenerative energy of an automobile or the like may be input. it can.

[Automobile]
A vehicle according to an embodiment of the present invention is a vehicle including the motor and/or the generator.
FIG. 5 is a conceptual diagram showing power generation, power storage, and a drive mechanism of the vehicle according to the embodiment of the present invention. The automobile 40 has wheels 41 and a motor 42, which are connected by an axle 45. The motor 42 is a motor having the rare earth magnet described above, and the wheels 41 are rotated by the output of this motor.

The motor 42 is electrically connected to the storage battery 43, and electric energy is input from the storage battery 43 to the motor 42. The storage battery 43 is electrically connected to the generator 44, and the electric power generated by the generator 44 is supplied to the storage battery 43. The generator 44 is a generator having the rare earth magnet already described.
The generator 44 is connected to an engine (not shown) by a shaft, and the rotor of the generator 44 is configured to rotate by mechanical energy generated from the engine.

In the automobile 40, both the motor 42 and the generator 44 have a rare earth magnet, but the automobile according to the embodiment of the present invention is not limited to the above, and either the rare earth magnet or the generator is used. One may have a rare earth magnet.

The present invention will be described in more detail based on the following examples. The materials, usage amounts, ratios, processing contents, processing procedures, and the like shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be limitedly interpreted by the following examples.

(Formation of rare earth magnet precursor)
Amorphous NiTa (10 nm) was deposited at room temperature on a Si substrate with a thermal oxide film (corresponding to a support) using a DC magnetron sputtering method to obtain an amorphous NiTa layer (corresponding to a buffer layer). Next, polycrystalline MgO (10 nm) was deposited on the amorphous NiTa layer by the same method to obtain a polycrystalline MgO layer (corresponding to the second underlayer). Then, V (10 nm) was formed on the polycrystalline MgO layer by the same method to form a V layer (corresponding to the first underlayer), and a support with an underlayer was obtained.
Next, the support with the underlayer is heated to 400° C., and Sm, Fe, and Co targets are simultaneously sputtered to form a rare earth magnet precursor (Sm(Fe _0.8 Co _{0. 2} ) ₁₂ polycrystalline phase layers) were deposited. Further, V (10 nm) was laminated as a cap layer on the rare earth magnet precursor.

The out-of-plane of the rare earth magnet precursor prepared above and the XRD pattern measured by adjusting the χ axis (described as “tune χ” in the figure) are shown in FIG. 6. According to the out-of-plane measurement result, (002) and (004) diffraction patterns were observed as the patterns derived from the rare earth magnet precursor, and Sm(Fe _0.8 Co _0.2 ) ₁₂ polycrystals were observed. It was found that the c-axis was oriented along the thickness direction of the film. Furthermore, by adjusting the χ-axis, the superlattice peaks (132) and (332) of the ThMn ₁₂ type crystal structure were observed.
From the above results, the rare earth magnet precursor is Sm(Fe _0.8 Co _0.2 ) ₁₂ polycrystal having a ThMn ₁₂ type crystal structure in which the c-axis is preferentially oriented along the thickness direction of the film. Was confirmed.

FIG. 7 shows a cross-sectional TEM image of the sample, and FIG. 8 shows its in-plane TEM image. It can be seen from the cross-sectional TEM image that column-shaped Sm(Fe _0.8 Co _0.2 ) ₁₂ particles grow on the underlayer. In addition, it can be seen from the in-plane TEM image that it has a polycrystalline structure with a grain size of about 30 nm. Selected area diffraction also suggested a (001) orientation.

FIG. 9 shows the out-of-plane and in-plane magnetization curves of the rare earth magnet precursor (Sm(Fe _0.8 Co _0.2 ) ₁₂ anisotropic polycrystalline film).
The rare earth magnet precursor shows a strong perpendicular magnetic anisotropy, which is presumed to be derived from the c-axis orientation of the main phase shown by XRD measurement. At this time, the saturation magnetization was 1.61T and the coercive force was 0.48T.
When the (BH)-H curve was plotted based on FIG. 10 after demagnetizing field correction with a demagnetizing factor of 0.45 (FIG. 11), (BH)max was estimated to be 267 kJ/m ³ .

(Formation of rare earth magnet)
A rare earth magnet precursor layer was formed on a support with an underlayer in the same manner as above except that the cap layer was not formed on the rare earth magnet precursor. Next, the non-ferromagnetic element M (Cu, Sm-Cu, La-Cu, Cu-Ga, Zn, Al-Zn, Mg-Zn, and Sn-Zn) is deposited at room temperature, and then supported. The whole body was heated at 300 to 600° C. (30 minutes) to obtain a rare earth magnet (laminate) according to the embodiment of the present invention on the underlayer.
In addition, "-" in this paragraph represents an alloy or a laminated body of two kinds of metals.

FIG. 12 shows an XRD pattern of a rare earth magnet obtained by forming a Cu—Ga (3 nm) film as the non-ferromagnetic element M and then heating it at 450° C. (hereinafter, also referred to as “diffusion treatment”). As in the case before heating, (002) and (004) peaks of the 1-12 phase were observed.
FIG. 13 shows an in-plane TEM image after the Cu-Ga diffusion treatment. After Cu-Ga diffusion treatment, the same polycrystalline structure as before the diffusion treatment was maintained.

FIG. 14 shows an in-plane ADF-STEM image of the laminated body after the Cu-Ga diffusion treatment. Further, FIG. 15 shows EDS mapping (line analysis profile obtained by energy dispersive X-ray analysis method) of Sm, Fe, Co, Cu, and Ga elements in the same visual field. At this time, the composition of the main phase was calculated to be Sm(Fe _0.77 Co _0.2 Cu _0.01 Ga _0.02 ) _10.6 , which corresponds to the composition of the approximately 1-12 phase (1-12 crystal structure). Was. In addition to the main phase, the presence of Sm-Ga rich phase and Fe-Co rich phase was also confirmed. Further, it can be seen that Cu is selectively distributed in the crystal grain boundaries (grain boundary phase) of the main phase.

FIG. 16 shows an EDS line scan profile (line analysis profile) at the crystal grain boundaries in FIG. 15 (along the direction of A→B). In the figure, the region sandwiched by broken lines is defined as a grain boundary phase, and the composition of the grain boundary phase has a lower Fe concentration and a higher Cu and Ga concentration than the main phase. FIG. 17 shows the total concentration of Cu and Ga corresponding to the element M in the line analysis profile of FIG.

FIG. 18 shows EDS mapping in the same field of view observed by ADF-STEM on the cross section of the laminated body after the Cu—Ga diffusion treatment. It can be seen that Cu and Ga are diffusing into the grain boundary phase having a low Fe concentration.
When the total composition is obtained from this entire field of view by energy dispersive X-ray analysis, Sm _8.18 Fe _67.64 Co _18.95 Cu _3.29 Ga _1.94 (each numerical value is the content based on the number of atoms (at .%).

FIG. 19 shows the EDS line scan profile (line analysis profile) at the crystal grain boundaries (along the direction C→D) obtained from the cross-sectional image. The same tendency as the EDS line scan profile in the in-plane image of FIG. 15 is obtained, and the Fe concentration is low and the Cu and Ga concentrations are high in the grain boundary phase. FIG. 20 shows the total concentration of Cu and Ga corresponding to the element M in the line analysis profile of FIG.

FIG. 21 shows the out-of-plane and in-plane magnetization curves of the rare earth magnet after the Cu—Ga diffusion treatment. It was found that the same strong perpendicular magnetic anisotropy was exhibited as before the diffusion treatment. At this time, the saturation magnetization was 1.61T. On the other hand, the coercive force increased to 0.84T, and it was found that the desired effect was obtained. When the demagnetizing field was corrected, (BH)max was calculated to be 375 kJ/m ³ .

FIG. 22 shows a comparison of demagnetization curves before and after Cu-Ga diffusion treatment. The sample after the Cu—Ga diffusion treatment was compared with the sample before and after the heat treatment of the rare earth magnet precursor (Sm(Fe _0.8 Co _0.2 ) ₁₂ anisotropic polycrystalline film) on which no Cu—Ga film was formed. It was found that the coercive force increased from 0.48T to 0.84T.

FIG. 23 shows the heating temperature and the gain in the coercive force diffusion process of the rare earth magnet precursor (Sm(Fe _0.8 Co _0.2 ) ₁₂ anisotropic polycrystalline film) obtained by diffusing various non-ferromagnetic elements M. The coercive force (that is, heat treatment temperature dependency) of the rare earth magnet used is shown. The coercive force of 0.78T, 0.84T, and 0.87T was obtained in the samples in which Cu diffusion, Cu-Ga diffusion, and Mg-Zn diffusion were performed, respectively. It can be seen that when the heating temperature in the diffusion treatment is 350 to 450° C., a rare earth magnet having more excellent effects of the present invention can be obtained.

FIG. 24 shows a recoil curve before and after the Cu—Ga diffusion treatment, that is, in the demagnetization process of the rare earth magnet and the rare earth magnet precursor. Before the diffusion treatment (rare earth magnet precursor), hysteresis was observed in the minor loop in the applied magnetic field of 0.7 T or more.
On the other hand, in the sample (rare earth magnet) after Cu—Ga diffusion, no hysteresis was observed in the minor loop even in the applied magnetic field of 1 T or more, and the inclination was small. It is presumed that this is because the irreversible domain wall movement was reduced by the diffusion process.

FIG. 25 shows the temperature dependence of the coercive force of the rare earth magnet before the diffusion treatment (rare earth magnet precursor) and after the diffusion treatment with Cu or Cu—Ga. For comparison, the temperature dependence of the coercive force of a commercial Nd-Fe-B sintered magnet containing (or not containing) Dy is also shown. The temperature coefficient β of the coercive force is −0.31%/K for the rare earth magnet precursor (Sm(Fe _0.8 Co _0.2 ) ₁₂ ) before the diffusion treatment, and −0.18%/K after the Cu diffusion treatment. After K and Cu-Ga diffusion treatment, it was calculated to be -0.20%/K. These values were superior to those of the commercial Nd-Fe-B sintered magnet (β=-0.6 to -0.4%/K).

Since the rare earth magnet according to the embodiment of the present invention has an excellent coercive force, it can be applied to a field of MEMS (Micro Electro Mechanical Systems), an energy field such as energy harvesting (environmental power generation), and a field of medical equipment.
Among them, the motor and the generator having the rare earth magnet have excellent characteristics, and thus can be preferably used for transportation machines such as automobiles and trains.

10: laminated body 11: cap layer 12: rare earth magnet layer 13: first underlayer 14: second underlayer 15: underlayer 16: buffer layer 17: support 20: permanent magnet motor 21: stator 22: core material 23: rare earth magnet 24: rotor 30: generator 31: stator 32: rotor 33: turbine 34: shaft 40: automobile 41: wheel 42: motor 43: storage battery 44: generator 45: axle

Claims (19)

A rare earth magnet having a main phase and a grain boundary phase arranged to cover at least a part of the main phase,
R ¹ is at least one selected from the group consisting of La, Pr, Sm, Nd, Eu, Tb, and Lu,
R ² is at least one selected from the group consisting of Y, Er, Tm, Ce, Dy, Ho, Yb, Gd, and Zr,
T is at least one selected from the group consisting of Fe, Co, and Ni,
M is at least one selected from the group consisting of Cu, Ga, Zn, Al, Mg, Sn, Ge, Au, Si, Ca, and Ag,
x is a number from 100/13 to 100/11,
y is a number exceeding 0 and 10 or less,
When p is a number of 0.5 to 1, the overall composition is
Formula _^1: is represented by _{^{(R 1 p R 2 1-}} p) x M y T 100-x-y, at least the main phase has a crystal structure of _12-inch ThMn,
The grain boundary phase is based on a position P _{max at} which the content of the atomic unit of M in the rare earth magnet specified by a line analysis profile obtained by an energy dispersive X-ray analysis method has a maximum value. A rare earth magnet defined as a region between two positions P _{boundary at which} the content becomes ½ of the maximum value before and after the position P _max in the line analysis profile. The rare earth magnet according to claim 1, wherein the particle diameter of the main phase is 1 μm or less. The main phase does not substantially contain any of Al, Si, Ti, V, Mo, Nb, Cr, Mn, C, B, Mg, Cu, Zn, and W. The rare earth magnet described. The rare earth magnet according to any one of claims 1 to 3, wherein the T is Fe and Co. The rare earth magnet according to any one of claims 1 to 4, wherein the M is at least one selected from the group consisting of Cu and Ga. The rare earth magnet according to claim 1, wherein at least one selected from the group consisting of the crystal orientation of the main phase and the easy axis of magnetization is preferentially oriented along a predetermined direction. A film containing the rare earth magnet according to claim 1. The film according to claim 7, wherein at least one selected from the group consisting of the crystal orientation of the main phase and the easy axis of magnetization is preferentially oriented along the thickness direction. An underlayer, and a rare earth magnet layer containing the rare earth magnet according to any one of claims 1 to 6 formed in contact with the underlayer, wherein the underlayer has a polycrystalline structure. And the crystal orientation is preferentially oriented along the thickness direction of the underlayer. The laminate according to claim 9, wherein the crystal orientation of the main phase of the rare earth magnet layer is preferentially oriented along the thickness direction of the rare earth magnet layer. The laminate according to claim 9 or 10, wherein the underlayer is a underlayer with a support layer further having a support. The laminate according to claim 11, wherein the base layer with the support layer further has a buffer layer between the base layer and the support. The laminated body according to any one of claims 9 to 12, further comprising a cap layer. A polycrystalline phase having a ThMn ₁₂ type crystal structure,
R ¹ is at least one selected from the group consisting of La, Pr, Sm, Nd, Eu, Tb, and Lu,
R ² is at least one selected from the group consisting of Y, Er, Tm, Ce, Dy, Ho, Yb, Gd, and Zr,
T is at least one selected from the group consisting of Fe, Co, and Ni,
x is a number from 100/13 to 100/11,
When p is a number of 0.5 to 1,
Formula _{^{2: (R 1 p R 2}} 1-p) X T 100-X
A step 1 of forming a rare earth magnet precursor containing a compound represented by
At least one selected from the group consisting of Cu, Ga, Zn, Al, Mg, Sn, Ge, Au, Si, Ca, and Ag so as to cover at least a part of the surface of the rare earth magnet precursor. A step 2 of disposing a non-ferromagnetic element-containing layer containing the element M to form a rare earth magnet precursor with a non-ferromagnetic element-containing layer;
A step 3 of heating the rare earth magnet precursor with a non-ferromagnetic element-containing layer to diffuse the element M in the rare earth magnet precursor to obtain the rare earth magnet according to any one of claims 1 to 6, A method for manufacturing a rare earth magnet having: The step 1 is a step of forming a rare earth magnet precursor layer containing a rare earth magnet precursor on the underlayer, the underlayer has a polycrystalline structure, and the crystal orientation is in the thickness direction of the underlayer. 15. The method for producing a rare earth magnet according to claim 14, wherein the rare earth magnet is preferentially oriented along the direction. A motor comprising the rare earth magnet according to claim 1. An automobile having the motor according to claim 16. A generator comprising the rare earth magnet according to claim 1. An automobile having the generator according to claim 18.