JP7247548B2 - Rare earth magnet and manufacturing method thereof - Google Patents

Description

The present disclosure relates to an R—Fe—B system rare earth magnet (R is a rare earth element) and a method for producing the same. In particular, the present disclosure relates to an R—Fe—B rare earth magnet whose coercive force is suppressed from decreasing at high temperatures, and a method for producing the same.

An R--Fe--B rare earth magnet comprises a main phase and grain boundary phases around the main phase. The main phase has a composition represented by R ₂ Fe ₁₄ B and is a magnetic phase. This main phase exhibits strong magnetism. On the other hand, the grain boundary phase exists around the main phase and separates the main phases magnetically. This magnetic division enhances the coercive force of the R—Fe—B system rare earth magnet.

Various attempts have been made to enhance this magnetic separation effect. For example, Patent Document 1 discloses a rare earth magnet obtained by using a rare earth magnet having a main phase and a grain boundary phase as a precursor and infiltrating a modifier into the interior of the precursor.

In the rare earth magnet disclosed in Patent Document 1, the coercive force of the entire rare earth magnet is enhanced by having an intermediate phase between the main phase and the grain boundary phase.

International Publication No. 2014/196605A1

Due to their high performance, R--Fe--B rare earth magnets are being used in a wide variety of fields. Therefore, the use of R--Fe--B rare earth magnets in high-temperature environments is also increasing. In addition, when the R--Fe--B rare earth magnet is used in a high-output motor and the high output is maintained for a long period of time, the temperature of the R--Fe--B rare earth magnet may become high due to self-heating of the motor. .

It is known that the coercive force of an R--Fe--B rare earth magnet may decrease when the temperature is high.

Accordingly, the present inventors have found that there is a demand for an R--Fe--B rare earth magnet which is capable of suppressing a decrease in coercive force even at high temperatures. In this specification, high temperature means a temperature range of 130 to 170°C, particularly 140 to 160°C. Further, room temperature means a range of 20 to 25°C. An R--Fe--B rare earth magnet comprises a main phase and a grain boundary phase existing around the main phase, and the main phase contains a phase having a composition represented by _{R.sub.2Fe.sub.14B .} It refers to a magnet that has

The present disclosure has been made to solve the above problems. An object of the present disclosure is to provide an R--Fe--B rare earth magnet in which a decrease in coercive force is suppressed even at high temperatures, and a method for producing the same.

In order to achieve the above object, the present inventors have made intensive studies and completed the rare earth magnet of the present disclosure and the method for producing the same. The rare earth magnet of the present disclosure and its manufacturing method include the following embodiments.
<1> a main phase,
a grain boundary phase existing around the main phase;
with
The overall composition has the formula (Nd _x (Ce, La) _(1-xy) R ¹ _y ) _p Fe _(100-pqr-s) Co _q B _r M ¹ _s (R ² _z R ³ _w M ² _1-zw ) _t (where R ¹ is one or more selected from rare earth elements other than Nd, Ce, and La, and R ² is Pr, Nd, Pm, Sm, Eu , and Gd, R ³ is one or more selected from rare earth elements other than R ² , M ¹ is Ga, Al, Cu, Au, Ag, Zn, In, and Mn is one or more selected from Mn and an unavoidable impurity element, ^{and M2} increases the melting point of ^R2zR3wM21 _{-zw to} ^R2 by alloying with ^R2 _and ^{R3 .} An alloy element and an unavoidable impurity element that lowers the melting point of
p, q, r, s, and t in atomic %,
5.0≦p≦20.0,
0≤q≤8.0,
4.0≦r≦6.5,
0≦s≦2.0 and 0≦t≦10.0
and
x, y, z, and w, in molar ratios,
0.4≦x≦0.8,
0≤y≤0.1,
0.5≦z≦0.8 and 0≦w≦0.1
is. ), and
The La is contained in a molar ratio of 1/9 to 3 times as much as the Ce,
Rare earth magnet.
<2> The rare earth magnet according to <1>, wherein La is contained in a molar ratio of 1/9 to 2 times as much as Ce.
<3> Further comprising an intermediate phase between the main phase and the grain boundary phase,
wherein t is 0.1 ≤ t ≤ 10.0, and the concentration of ^R2 is higher in the intermediate phase than in the main phase;
A rare earth magnet according to <1> or <2>.
<4> The rare earth magnet according to any one of <1> to <3>, wherein ^R2 is Nd.
<5> The rare earth magnet according to <3> or <4>, wherein the concentration of ^R2 is 1.5 to 8.0 times higher in the main phase than in the intermediate phase.
<6> The rare earth magnet according to any one of <3> to <5>, wherein the intermediate phase has a thickness of 2 to 100 nm.
<7> Formula (Nd _x (Ce, La) _(1-xy) R ¹ _y ) _p Fe _(100-pqr-s) Co _q B _r M ¹ _s (where R ¹ is Nd, Ce, and one or more selected from rare earth elements other than La, M ¹ is one or more selected from Ga, Al, Cu, Au, Ag, Zn, In, and Mn, and inevitable impurities is an element, and
p, q, r, and s in atomic %,
5.0≦p≦20.0,
0≤q≤8.0,
4.0≦r≦6.5 and 0≦s≦2.0
and
x and y, in molar ratio,
0.4≦x≦0.8 and 0≦y≦0.1
is. ) and contains the La in a molar ratio of 1/9 to 3 times the Ce,
quenching the molten metal to obtain a ribbon;
Hot compressing a plurality of ribbons to obtain a compact, and Hot compressing the compact to obtain a compact,
including,
A method for producing a rare earth magnet.
<8> The method according to <7>, wherein the molten metal contains the La in a molar ratio of 1/9 to 2 times the Ce.
<9> Formula R ² _z R ³ _w M ² _1-zw (where R ² is one or more selected from Pr, Nd, Pm, Sm, Eu, and Gd, and R ³ is R 2 is one or more selected from rare earth elements other than ² , and M ² is alloyed with R ² and R ³ to increase the melting point of R ² _z R ³ _w M ² _1-zw to the melting point of R ² An alloy element and an unavoidable impurity element that lower than preparing a modifier containing
Bringing the compressed body and the modified material into contact with each other to obtain a contact body, and heat-treating the contact body to allow the melt of the modified material to permeate the inside of the compressed body;
including,
The method according to <7> or <8>.
<10> The method according to <9>, wherein the ^R2 is Nd.
<11> The molded body is compressed at a strain rate of 0.001/s or more and less than 0.1/s, a rolling reduction of 50 to 70%, and a temperature of 700 to 800 ° C. to obtain a compressed body. The method according to any one of items 7> to <10>.

According to the present disclosure, by coexisting Nd, Ce, and La and setting the content ratio of Ce and La within a predetermined range, a rare earth magnet that suppresses a decrease in coercive force at high temperatures and a method for producing the same are provided. can do.

FIG. 1 is a diagram showing content ratios of Nd, Ce, and La. FIG. 2 is a diagram schematically showing one aspect of the structure of a rare earth magnet according to the present disclosure. FIG. 3 is a diagram illustrating another embodiment of the organization of a rare earth magnet according to the present disclosure. 4 is a graph showing the relationship between temperature and coercive force for the samples of Example 15 and Comparative Example 1. FIG. 5 is a diagram showing the relationship between temperature and residual magnetization for the samples of Example 15 and Comparative Example 1. FIG. FIG. 6 is a diagram showing tissue observation and component analysis positions for the sample of Example 6. FIG. 7 is a diagram showing the results of structural observation and component analysis of the sample (first field of view) of Example 6. FIG. FIG. 8 is a diagram showing the results of structural observation and component analysis of the sample (second field of view) of Example 6. FIG. FIG. 9 is a diagram showing tissue observation and component analysis positions for the sample of Example 12. FIG. 10 is a diagram showing the results of structural observation and component analysis of the sample (first field of view) of Example 12. FIG. FIG. 11 is a diagram showing the results of structural observation and component analysis of the sample of Example 12 (second field of view). FIG. 12 is a diagram showing tissue observation and component analysis positions for the sample of Example 17. FIG. FIG. 13 is a diagram showing the results of structural observation and component analysis of the sample (first field of view) of Example 17. FIG. FIG. 14 is a diagram showing the results of structural observation and component analysis of the sample of Example 17 (second field of view). FIG. 15 is a diagram showing an example of grain size t of crystal grains in the sample of Example 39. In FIG. FIG. 16 is a diagram showing an example of grain size t of crystal grains for the sample of Example 40. In FIG. FIG. 17 is a diagram showing an example of grain size t of crystal grains in the sample of Example 6. In FIG. FIG. 18 is a diagram showing an example of grain size t of crystal grains for the sample of Example 12. In FIG. 19 is a diagram showing the tissue observation results and component analysis positions for the sample of Example 39. FIG. FIG. 20 is a diagram showing the results of component analysis at positions indicated by white lines in FIG. FIG. 21 is a diagram showing tissue observation results and component analysis positions for the sample of Example 40. FIG. FIG. 22 is a diagram showing the results of component analysis at positions indicated by white lines in FIG. 23 is a diagram showing the tissue observation results and component analysis positions for the sample of Example 6. FIG. FIG. 24 is a diagram showing the results of component analysis at positions indicated by white lines in FIG. 25 is a diagram showing the tissue observation results and component analysis positions for the sample of Example 12. FIG. FIG. 26 is a diagram showing the results of component analysis at positions indicated by white lines in FIG.

Hereinafter, embodiments of a rare earth magnet and a method for manufacturing the same according to the present disclosure will be described in detail. It should be noted that the embodiments shown below do not limit the rare earth magnet and the manufacturing method thereof according to the present disclosure.

In the R—Fe—B system rare earth magnet, coercive force can be increased by 1) reducing the grain size of the main phase, 2) increasing the anisotropic magnetic field of the main phase, and 3) magnetically separating the main phases. improves.

In order to reduce the grain size of the main phase, the main phase of the R--Fe--B rare earth magnet is nano-crystallized by liquid quenching or the like. As a result, a large amount of R ₂ Fe ₁₄ B phase exists as the main phase in the R—Fe—B system rare earth magnet, and grain boundary phases exist around the main phase. The grain boundary phase includes an R-rich phase containing excess R and a small amount of magnetic phase containing Fe (for example, RFe ₂ phase).

The Nd ₂ Fe ₁₄ B phase has a high anisotropic magnetic field at room temperature, but the Curie point is 320° C., which is not very high. Therefore, even if the Curie point is not reached, the anisotropic magnetic field of the Nd ₂ Fe ₁₄ B phase decreases at high temperatures. On the other hand, a magnetic phase containing Fe (for example, the RFe ₂ phase) is paramagnetic at temperatures higher than room temperature, but there is a possibility of propagating the magnetic spin interaction between the Nd ₂ Fe ₁₄ B phases (crystal grains). be. When a large amount of Nd ₂ Fe ₁₄ B phase is present as the main phase, the coercive force is high at room temperature because the effect of the magnetic phase containing Fe in the grain boundary phase is small. However, at high temperatures, the magnetic phase containing Fe in the grain boundary phase has the effect of propagating the magnetic spin interaction between the Nd ₂ Fe ₁₄ B phases (main phases). As a result, the grain size of the main phase apparently increases, and the effect of nanocrystallization of the main phase may decrease. As a result, the coercive force drops sharply.

When R of the R—Fe—B system rare earth magnet contains Nd, Ce, and La, the anisotropic magnetic field of (Nd, Ce, La) ₂ Fe ₁₄ B at both room temperature and high temperature is Nd ₂ Lower than the anisotropy field of Fe ₁₄ B. Hereinafter, the R—Fe—B system rare earth magnet containing Nd, Ce, and La is sometimes referred to as “(Nd, Ce, La)—Fe—B system rare earth magnet”.

Although not bound by theory, in the (Nd, Ce, La)-Fe-B rare earth magnet, when the content ratio of Ce and La is within a predetermined range, compared with the Nd-Fe-B rare earth magnet, The stability of the magnetic phase ( _RFe2 phase, etc.) containing Fe in the grain boundary phase is lowered. As a result, in the (Nd, Ce, La)--Fe--B rare earth magnet, Fe in the grain boundary phase easily contributes to the formation of phases other than the magnetic phase containing Fe. Phases other than the magnetic phase containing Fe include a CeFe ₂ phase and the like.

The production of the (Nd, Ce, La) ₂ Fe ₁₄ B phase increases the total number of main phases. As a result, the decrease in the anisotropic magnetic field due to the replacement of Nd with Ce and La is compensated for, and the decrease in the coercive force of the (Nd, Ce, La)--Fe--B system rare earth magnet as a whole is suppressed. This coercive force improvement is remarkable at high temperatures. In this specification, although not bound by theory, the (Nd, Ce, La) ₂ Fe ₁₄ B phase has Ce or La at the position of Nd in the Nd ₂ Fe ₁₄ B phase.

In addition, when a (Nd, Ce, La)-Fe-B-based rare earth magnet is used as a precursor and a modifier containing R ² is permeated into the precursor, the permeation amount of the alloy in the modifier is In some cases, an intermediate phase is generated between the main phase and the grain boundary phase.

Without being bound by theory, it is believed that some of the Ce and/or La present in the main phase of the precursor are replaced with ^R2 to produce the intermediate phase. Therefore, the anisotropy field of the mesophase is higher than that of the main phase of the precursor, since there is a higher concentration of ^R2 in the mesophase than in the main phase of the precursor. At higher temperatures, the anisotropy field of the mesophase decreases. However, even at high temperatures, the anisotropy field of the intermediate phase is higher than that of the main phase of the precursor due to the higher concentration of ^R2 compared to the main phase of the precursor. As a result, it contributes to suppression of coercive force reduction.

From what has been explained so far, the present inventors have found that it is possible to suppress a decrease in coercive force at high temperatures with respect to R—Fe—B rare earth magnets.

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

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

<Overall composition>
The overall composition of the rare earth magnet of the present disclosure is represented by the formula (Nd _x (Ce, La) _(1-xy) R ¹ _y ) _p Fe _(100-pqr-s) Co _q B _r M ¹ _s Represented by (R ² _z R ³ _w M ² _1-zw ) _t .

In the above formula, (R ² _z R ³ _w M ² _1-zw ) _t represents the composition derived from the modifier, which will be described later. When no modifier is permeated, t=0, and the overall composition of the rare earth magnet of the present disclosure is (Nd _x (Ce, La) _(1-xy) R ¹ _y ) _p Fe _{(100-p- qrs)} Co _q B _r M ¹ _s .

On the other hand, when the modifier is permeated, t is a non-zero positive value and (Nd _x (Ce, La) _(1-xy) R ¹ _y ) _p Fe _{(100-pqr- s)} Co _q B _r M ¹ _s represents the composition of the rare earth magnet precursor.

In the above formula, Nd is neodymium, Ce is cerium, La is lanthanum, ^R1 is one or more selected from rare earth elements other than Nd, Ce, and La, Fe is iron, Co is cobalt, and B is boron is. ^M1 is one or more selected from Ga, Al, Cu, Au, Ag, Zn, In, and Mn, and an unavoidable impurity element. Ga is gallium, Al is aluminum, Cu is copper, Au is gold, Ag is silver, Zn is zinc, In is indium, and Mn is manganese. ^R2 is one or more selected from Pr, Nd, Pm, Sm, Eu, and Gd. Pr is praseodymium, Nd is neodymium, Pm is promethium, Sm is samarium, Eu is eurobium and Gd is gadolinium. ^M2 is an alloying ^element and an unavoidable impurity element that lowers the _melting point of ^R2zR3wM21 _{- zw} below that of ^R2 by alloying with ^{R2 and} R3 ^. .

In this specification, the rare earth elements are 17 elements of Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. Among these, Sc, Y, La, and Ce are light rare earth elements. Pr, Nd, Pm, Sm, Eu, and Gd are middle rare earth elements. Tb, Dy, Ho, Er, Tm, Yb, and Lu are heavy rare earth elements. In general, heavy rare earth elements are highly rare, and light rare earth elements are relatively rare. The rarity of the medium rare earth elements is between the heavy rare earth elements and the light rare earth elements.

Next, p, q, r, s, and t, and x, y, z, and w are explained. The following description explains the case of infiltrating the modifier. In the case where the modifying material is not permeated, the "rare earth magnet precursor" shall be read as "rare earth magnet", and the description regarding matters derived from the modifying material shall be treated as non-existent.

In the rare earth magnet precursor, p is the total content of Nd, Ce, La, and ^R1 , q is the content of Co, r is the content of B (boron), and s is , is the content of M ¹ . Regarding matters derived from the modifier, t is the penetration amount of the alloy in the modifier with respect to the rare earth magnet precursor, and is the total content of R ² , R ³ and M ² . The values for p, q, r, s, and t are each in atomic %.

In the rare earth magnet precursor, the values of x and y are the following content ratios (molar ratios). x indicates the content ratio of Nd with respect to the total content of Nd, Ce, La and ^R1 . y indicates the content ratio of ^R1 to the total content of Nd, Ce, La and ^R1 . Regarding matters derived from the modifier, the values of z and w are the following content ratios (molar ratios). z represents the content ratio of R ² with respect to the total content of R ² , R ³ and M ² . w indicates the content ratio of R ³ to the total content of R ² , R ³ and M ² .

The constituent elements of the rare earth magnet precursor represented by the above formula will be described below.

<Nd>
Nd is an essential component of the rare earth magnet precursor of the present disclosure. By containing Nd, high magnetization can be exhibited at room temperature and high temperature. Also, at room temperature, the Nd ₂ Fe ₁₄ B phase has a high anisotropy field.

〈Ce〉
Ce is an essential component of the rare earth magnet precursors of the present disclosure. Substitution of Nd in the main phase (Nd ₂ Fe ₁₄ B phase) with Ce facilitates generation of a magnetic phase containing Fe in the grain boundary phase, ie, a CeFe ₂ phase. The _CeFe2 phase is paramagnetic, and the effect of propagating the magnetic spin interaction between the main phases is expected, reducing the coercive force. In order to suppress the decrease in coercive force, it is necessary to decrease the stability of the magnetic phase containing Fe in the grain boundary phase.

Also, Ce can be trivalent or tetravalent. Without being bound by theory, La works to make most of Ce trivalent. Since 4f electrons are localized in trivalent Ce, the magnetization is improved, which is advantageous.

<La>
La is an essential component of the rare earth magnet precursor of the present disclosure. Substitution of La for Nd in the main phase (Nd ₂ Fe ₁₄ B phase) reduces the stability of the magnetic phase containing Fe in the grain boundary phase. This is because the compounds of La and transition metals such as Fe are thermodynamically unstable as a whole and do not mix. In other words, the addition of La is expected to have the effect of suppressing the formation of the RFe ₂ phase. Therefore, La greatly contributes to suppression of reduction in coercive force. Moreover, it is advantageous that La is cheaper than Nd. Also, the addition of Ce facilitates the formation of the CeFe ₂ phase, which lowers the coercive force. However, by adding La at the same time as Ce, the generation of the CeFe ₂ phase is suppressed, and the propagation of the magnetic spin interaction between grains of the main phase is suppressed.

<Content ratio of Nd, Ce, and La>
As described above, x is the content ratio of Nd. The saturation magnetization and the anisotropy field are higher in _{the Nd2Fe14B} phase than in the _{Ce2Fe14B and La2Fe14B} phases _. From this, if x is 0.40 or more, it is easy to obtain desired magnetization and coercive force in the rare earth magnet of the present disclosure. From this point of view, x may be 0.45 or greater, 0.50 or greater, or 0.55 or greater. On the other hand, if x is 0.80 or less, the content ratio of Ce and La is too small, and it is not difficult to obtain the effects of Ce and La. From this point of view, x may be 0.75 or less, 0.70 or less, or 0.65 or less.

In the rare earth magnet precursor, the content of La is 1/9 to 3 times the content of Ce in molar ratio. FIG. 1 is a diagram showing content ratios of Nd, Ce, and La. In FIG. 1, the straight line indicated by (1) indicates a composition in which the content of La is 1/9 times the content of Ce in terms of molar ratio. The straight line indicated by (2) indicates a composition in which the content of La is 1/3 times the content of Ce in terms of molar ratio. The straight line indicated by (3) indicates a composition in which the content of La is 2/3 times the content of Ce in terms of molar ratio. The straight line indicated by (4) indicates a composition in which the content of La is three times the content of Ce in molar ratio.

In other words, the above is as follows. The straight line (1) indicates a composition of Ce:La=1:1/9. The straight line (2) indicates the composition where Ce:La=1:1/3. The straight line (3) indicates a composition of Ce:La=1:2/3. The straight line (4) indicates a composition of Ce:La=1:3.

As described above, the content ratio x of Nd is 0.4 to 0.8, so the composition of the rare earth magnet precursor of the present disclosure is sandwiched between “Nd80” and “Nd40” in FIG. It is indicated by the area and the overlapping portion of the area sandwiched by straight lines (1) and (4).

Desired magnetization can be obtained at room temperature and high temperature if the molar ratio of the La content to the Ce content is 1/9 or more. From this point of view, it is preferably 1/8 times or more, more preferably 1/7 times or more. On the other hand, when the La content is 3 times or less the Ce content, the Nd in the grain boundary phase is replaced with Ce and/or La, resulting in a magnetic phase containing Fe (RFe ₂ phases, etc.) is lowered, and the content (volume ratio) of the magnetic phase containing Fe is lowered. As a result, the grain boundary phase suppresses the effect of propagating the magnetic spin interaction between the main phases and suppresses the decrease in coercive force at high temperatures. From this point of view, it is preferably 5/2 times or less, more preferably 2 times or less.

<R ¹ >
R ¹ is one or more selected from rare earth elements other than Nd, Ce, and La. The rare earth magnet of the present disclosure has Nd, Ce, and La as essential components. It is difficult to eliminate rare earth elements ^R1 other than Nd, Ce, and La from the raw materials of these essential components. However, when the value of the content ratio y of R ¹ is 0 to 0.1, the properties of the rare earth magnet of the present disclosure can be considered to be substantially the same as when the value of y is 0.

Since excessively increasing the purity of the raw materials of the essential ingredients leads to an increase in manufacturing costs, the value of y is 0.01 or more, 0.02 or more, 0.03 or more, 0.04 or more, or 0.04 or more. 05 or more. On the other hand, the value of y should be as low as possible, and may be 0.09 or less, 0.08 or less, 0.07 or less, or 0.06 or less, as long as the manufacturing cost does not increase.

When the total content p of Nd, Ce, La, and ^R1 is 5.0 atomic % or more, the main phase represented by (Nd, Ce, La) ₂ Fe ₁₄ B is hardly generated. do not have. From the viewpoint of ease of formation of the main phase represented by (Nd, Ce, La) ₂ Fe ₁₄ B, p is 7.0 atomic % or more, 9.0 atomic % or more, 11.0 atomic % or more , or 13.0 atomic % or more. On the other hand, when p is 20.0 atomic % or less, the existence ratio (volume fraction) of the grain boundary phase does not become excessive. From the viewpoint that the existence ratio of the grain boundary phase does not become excessive, it may be 19.0 atomic % or less, 18.0 atomic % or less, or 17.0 atomic % or less.

<B>
B affects the content of the main phase and the content of the magnetic phase containing Fe in the grain boundary phase. If the B content is too low, the main phase represented by (Nd, Ce, La) ₂ Fe ₁₄ B will be difficult to generate. When the B content r is 4.0 atomic % or more, the main phase represented by (Nd, Ce, La) ₂ Fe ₁₄ B is not difficult to be generated. From this point of view, r may be 4.5 atomic % or more, 5.0 atomic % or more, or 5.5 atomic % or more. On the other hand, when the B content r is excessive, magnetic phases containing Fe such as the RFe ₄ B ₄ phase are likely to be generated in the grain boundary phase. If r is 6.5 atomic % or less, it is difficult to generate a large amount of α-Fe phase. From this point of view, r may be 6.3 atomic % or less or 6.0 atomic % or less.

〈Co〉
Co is an element that can be substituted for Fe in the main phase, grain boundary phase, and intermediate phase. In this specification, when Fe is described, part of Fe can be replaced with Co. For example, part of Fe in the (Nd, Ce, La) ₂ Fe ₁₄ B phase is replaced with Co to form the (Nd, Ce, La) ₂ (Fe, Co) ₁₄ B phase. Also, the magnetic phase containing Fe in the grain boundary phase (R ₂ Fe ₁₇ phase, etc.) becomes a magnetic phase (R ₂ (Fe, Co) ₁₇ phase, etc.) in which a part of the Fe is substituted with Co.

By substituting a part of Fe with Co in this way, the Curie point of each phase is improved. If the Curie point is not desired to be improved, Co may be omitted, and the inclusion of Co is not essential. When the Co content q is 0.5 atomic % or more, the Curie point is substantially improved. From the viewpoint of improving the Curie point, it may be 1.0 atomic % or more, 2.0 atomic % or more, 3.0 atomic % or more, or 4.0 atomic % or more. On the other hand, since Co is expensive, from an economical point of view, the Co content q may be 8.0 atomic % or less, 7.0 atomic % or less, or 0.6 atomic % or less.

^<M1>
M1 can be contained within a range that does not impair the properties of the rare earth magnet of the present disclosure. ^M1 may contain unavoidable impurity elements. Unavoidable impurity elements are impurity elements contained in the raw materials of rare earth magnets, or impurity elements mixed in during the manufacturing process. Impurity elements that increase costs. Impurity elements and the like that are mixed in during the manufacturing process include elements that are contained within a range that does not affect the magnetic properties due to manufacturing circumstances.

Ga, Al, Cu, Au, Ag, Zn, In, and Mn are examples of elements that can be contained within a range that does not impair the properties of the rare earth magnet of the present disclosure.

Ga, Al, Zn, In, Au, Ag and Cu lower the melting point of the grain boundary phase present inside the ribbon obtained by the liquid quenching method or the like. As a result, when obtaining a compact from a plurality of strips and/or when obtaining a compact from a compact, these elements may be included for improving the life of the mold, etc., but it is essential isn't it. These elements do not substantially affect the magnetic properties if the content of ^M1 is below the upper limit. These elements may be regarded as unavoidable impurity elements from the viewpoint of magnetic properties.

Mn replaces part of Fe in the (Nd, Ce, La) ₂ Fe ₁₄ B phase and contributes to stabilization of the (Nd, Ce, La) ₂ Fe ₁₄ B phase.

If the content s of ^M1 is 2.0 atomic % or less, the magnetic properties of the present disclosure are not impaired. From this point of view, the content s of ^M1 may be 1.5 atomic % or less, 1.0 atomic % or less, or 0.5 atomic %.

Even if M ¹ does not contain Ga, Al, Cu, Au, Ag, Zn, In, and Mn, the inevitable impurity elements cannot be eliminated, so the lower limit of the content s of M ¹ is 0 Even if it is 0.05 atomic %, 0.1 atomic %, or 0.2 atomic %, there is no practical problem.

Each of the values of p, q, r, and s explained so far are equivalent to those of a normal R--Fe--B rare earth magnet.

〈Fe〉
Fe is the remainder of Nd, Ce, La, R ¹ , Co, B, and M ¹ explained so far, and the Fe content (atomic %) is (100-pqrs). expressed. When p, q, r, and s are within the ranges described above, a main phase and a grain boundary phase are obtained. Further, when a rare earth magnet having a main phase and a grain boundary phase is used as a precursor and the modifier is sufficiently impregnated into the precursor, an intermediate phase is obtained. The main phase, grain boundary phase, and intermediate phase are described below.

<Main Phase, Grain Boundary Phase, and Intermediate Phase>
FIG. 2 is a diagram schematically showing one aspect of the structure of a rare earth magnet according to the present disclosure. FIG. 3 is a diagram illustrating another embodiment of the organization of a rare earth magnet according to the present disclosure.

2, the rare earth magnet 100 of the present disclosure has a main phase 10 and a grain boundary phase 20. In the embodiment shown in FIG. In the embodiment shown in FIG. 3 , the rare earth magnet 100 of the present disclosure has an intermediate phase 30 in addition to the main phase 10 and grain boundary phase 20 .

The embodiment shown in FIG. 2 is observed when no modifier or a very small amount of modifier is infiltrated. A rare earth magnet 100 of the embodiment shown in FIG. 2 is used as a rare earth magnet precursor that is impregnated with a modifier. The aspect shown in FIG. 3 is observed when the rare earth magnet precursor is impregnated with a sufficient amount of modifier.

The rare earth magnet 100 may contain phases (not shown) other than the main phase 10 , the grain boundary phase 20 and the intermediate phase 30 . Phases other than the main phase 10, the grain boundary phase 20, and the intermediate phase 30 include oxides, nitrides, intermetallic compounds, and the like.

The properties of the rare earth magnet 100 are mainly exhibited by the main phase 10, the grain boundary phase 20, and the intermediate phase 30. Most of the phases other than the main phase 10, the grain boundary phase 20, and the intermediate phase 30 are impurities. Therefore, the total content of the main phase 10, the grain boundary phase 20, and the intermediate phase 30 in the rare earth magnet 100 is preferably 95% by volume or more, more preferably 97% by volume or more, and even more preferably 99% by volume or more. .

The main phase 10 is nanocrystallized. Being nano-crystallized means that the main phase 10 has an average grain size of 1 to 1000 nm. The average particle size may be 10 nm or more, 50 nm or more, or 100 nm or more, and may be 900 nm or less, 700 nm or less, 500 nm or less, or 300 nm or less.

The “average particle size” is, for example, the average value of the longitudinal length t of the main phase 10 shown in FIG. For example, in a scanning electron microscope image or a transmission electron microscope image of the rare earth magnet 100, a certain area is defined, the average value of the length t of each of the main phases 10 existing in this certain area is calculated, and it is expressed as " "average particle size". When the cross-sectional shape of the main phase 10 is elliptical, the length of the major axis is t. When the cross section of the main phase is square, the length of the longer diagonal is t. In the case of the embodiment shown in FIG. 3, the intermediate phase 30 is also included in setting t. This is because the intermediate phase 30 is derived from the main phase 10 as will be described later.

Using the rare earth magnet 100 shown in FIG. 2 as a rare earth magnet precursor (hereinafter sometimes referred to as “precursor 100”), when the modifier is permeated into this, the modifier passes through the grain boundary phase 20, It reaches the interface between the main phase 10 and the grain boundary phase 20 . Then, ^R2 in the modifier permeates from the grain boundary phase 20 into the main phase 10, forming an intermediate phase 30 as shown in FIG.

The grain boundary phase 20 exists around the main phase 10 . Intermediate phase 30 is sandwiched between main phase 10 and grain boundary phase 20 . Formation of the intermediate phase 30 will be described in terms of the composition of the modifier.

<R ² , R ³ , and M ² >
The modifier contains an alloy having a composition represented by R ² _z R ³ _w M ² _1-zw . On the other hand, the precursor 100 is represented by (Nd _x (Ce, La) _(1-xy) R ¹ _y ) _p Fe _(100-pqr-s) Co _q B _r M ¹ _s have the composition

^R2 is one or more selected from Pr, Nd, Pm, Sm, Eu, and Gd. R ³ is one or more selected from rare earth elements other than R ² . ^M2 is ^an alloying element and an unavoidable impurity element ^that lowers the melting point of ^R2zR3wM21 _{- zw} below the _melting point of ^R2 by alloying with R2 and ^{R3 .} is.

The precursor 100 mainly contains Nd, Ce, and La as rare earth elements. On the other hand, the alloy in the modifier mainly contains ^R2 , which is one or more selected from Pr, Nd, Pm, Sm, Eu, and Gd, as a rare earth element.

Since R ² of the modifier and Nd, Ce, and La of the precursor 100 are different in type of one or more rare earth elements, it is not bound by theory, but R ² permeates the main phase 10 and penetrates the intermediate A phase 30 is formed. Therefore, the concentration of R ² is higher in the interphase 30 than in the main phase 10 . Although not bound by theory, the reason for the penetration of ^R2 into the main phase 10 is believed to be as follows.

When the modifier is infiltrated into the precursor 100 , the rare earth element in the modifier hardly penetrates into the main phase 10 when the alloy in the modifier mainly contains the same rare earth element as the main phase 10 . For example, when impregnating a Nd--Fe--B rare earth magnet precursor with a modifier containing an Nd--Cu alloy, Nd in the modifier tends to remain in the grain boundary phase 20 and the main phase (Nd ₂ (Fe ₁₄ B phase).

In contrast, when the alloy in the modifier mainly contains a rare earth element different from that of the main phase 10 , the rare earth element in the modifier easily penetrates into the main phase 10 . For example, when a modifier containing an Nd-Cu alloy is infiltrated into a (Nd, Ce, La)-Fe-B rare earth magnet, the presence of Ce and La causes Nd in the modifier to become the main phase Easy to penetrate 10. From the viewpoint of improving the saturation magnetization and anisotropic magnetic field of the intermediate phase 30 in a well-balanced manner, ^R2 is preferably Nd.

The composition of the alloy in the modifier is represented by R ² _z R ³ _w M ² _1-zw . R ³ is one or more selected from rare earth elements other than R ² . The rare earth element contained in the alloy in the modifier is ^R2 , but it is difficult to eliminate the rare earth element ^R3 other than ^R2 . However, if the value of the content ratio w of ^R3 is 0 to 0.1, it can be considered that the properties as a modifier are substantially the same as when the value of w is 0.

Ideally, the value of w is close to 0, but the value of w may be 0.01 or more, 0.02 or more, 0.03 or more, 0.04 or more, or 0.05 or more. On the other hand, the value of w is preferably as low as possible, and may be 0.09 or less, 0.08 or less, 0.07 or less, or 0.06 or less, as long as it does not increase the manufacturing cost.

Overall composition formula (Nd _x (Ce, La) _(1-xy) R ¹ _y ) _p Fe _(100-pqr-s) Co _q B _r M ¹ _s (R ² _z R ³ In _w M ² _1-zw ) _t , the value of t corresponds to the penetration of the alloy in the modifier relative to the precursor 100 (atomic %). The value of t varies the concentration of ^R2 in the interphase 30 and the thickness of the interphase 30 .

In FIG. 3, if the concentration of ^R2 is 1.5 times or more higher in the intermediate phase 30 than in the main phase 10, the magnetic decoupling can be clearly recognized. On the other hand, even if the concentration of ^R2 is 8.0 times higher in the intermediate phase 30 than in the main phase 10, the magnetic decoupling effect does not saturate. Therefore, the concentration of R ² is preferably 1.5 to 8.0 times higher in the interphase 30 than in the main phase 10 . The concentration of R ² may be 1.5-5.0 times higher, and may be 1.5-3.0 times higher.

In order to clearly recognize the function of the intermediate phase 30, the thickness of the intermediate phase 30 is preferably 2 nm or more, more preferably 10 nm or more, and even more preferably 20 nm or more. On the other hand, the thickness of the intermediate phase 30 depends on the penetration amount of the modifier. Since the modifier contains ^M2 that does not contribute to magnetization, if the permeation amount is too large, the volume fraction of the grain boundary phase increases and the magnetization of the rare earth magnet 100 decreases. From this point of view, the thickness of the intermediate phase 30 is preferably 100 nm or less, more preferably 70 nm or less, and even more preferably 40 nm or less.

"Production method"
Next, a method for manufacturing the rare earth magnet of the present disclosure will be described.

<Molten metal preparation>
Represented by the formula (Nd _x (Ce, La) _(1-xy) R ¹ _y ) _p Fe _(100-pqr-s) Co _q B _r M ¹ _s , and for Ce , and La in a molar ratio of 1/9 to 3 times. Alternatively, a molten metal containing 1/9 to 2 times La in molar ratio with respect to Ce may be prepared. Nd, Ce, La, R ¹ , Fe, Co, B, and M ¹ and x, y, p, q, r, and s are the same as the rare earth magnets. If a specific component is depleted during the preparation of the molten metal or in subsequent steps, that amount may be taken into consideration.

The method of preparing the melt is not limited, and includes, for example, high frequency melting of raw materials. In order to prevent oxidation of the raw material being melted and the molten metal being held, it is preferable to prepare the molten metal in an inert gas atmosphere.

<Fabrication of ribbon>
The molten metal is quenched to obtain a ribbon. There is no particular limitation on the quenching method as long as the main phase in the ribbon can be nanocrystallized. For example, a liquid quenching method can be mentioned. In order to nanocrystallize the main phase in the ribbon, the cooling rate of the molten metal is typically 1×10 ² K/sec or more, 1×10 ³ K/sec or more, 1×10 ⁴ K/sec or more. seconds or more, and may be 1×10 ⁷ K/sec or less, 1×10 ⁶ K/sec or less, or 1×10 ⁵ K/sec or less.

Conditions for the liquid quenching method include, but are not limited to, discharging the molten metal toward a single copper roll in an inert gas atmosphere with a reduced pressure of 50 kPa or less to obtain a ribbon.

The molten metal discharge temperature may typically be 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.

The peripheral speed of the single roll is typically 20 m/s or more, 24 m/s or more, or 28 m/s or more, and 40 m/s or less, 36 m/s or less, or 32 m/s or less. you can

<Production of compact>
The ribbon obtained by liquid quenching is hot compressed to obtain a compact. A compact is obtained from a plurality of strips. The method of compression is not particularly limited, but an example is hot pressing after inserting the strip into a die. The ribbon may be pulverized to 10 μm or less before hot pressing. The temperature during hot pressing may be a temperature at which a compact can be obtained, but may be a temperature at which a part of the grain boundary phase in the ribbon melts. That is, the ribbon may be liquid phase sintered. The atmosphere during hot pressing is preferably an inert gas atmosphere in order to prevent oxidation of the ribbon and compact. As for hot pressing, powder obtained by pulverizing the ribbon may be compacted to obtain a compact, and then the compact may be sintered (including liquid phase sintering).

The pressure during hot pressing may typically be 200 MPa or higher, 300 MPa or higher, or 350 MPa or higher, and may be 600 MPa or lower, 500 MPa or lower, or 450 MPa or lower.

The temperature during hot pressing may typically 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 pressing time during hot pressing may typically be 5 seconds or more, 20 seconds or more, or 40 seconds or more, and may be 120 seconds or less, 100 seconds or less, or 80 seconds or less.

<Preparation of compressed body>
The above molded body is further subjected to strong hot working to obtain a compressed body (plastically worked body). There is no particular limitation on the method of hot hard working (hereinafter sometimes simply referred to as "hard working") as long as a compressed body having anisotropy can be obtained. For example, the compact is placed in a cemented carbide mold and heavily worked at a rolling reduction of 10 to 75%. Upsetting, backward extrusion, and the like can be mentioned as methods of strong working. The draft may be set so as to obtain the desired anisotropy. The temperature at the time of heavy working may be set so that the compressed body is not destroyed and crystal grains in the compressed body are not coarsened.

The rolling reduction during heavy working may be typically 10% or more, 30% or more, 50% or more, 60% or more, and may be 75% or less, 70% or less, or 65% or less. .

The temperature during heavy working may be 650° C. or higher, 700° C. or higher, or 720° C. or higher, and may be 850° C. or lower, 800° C. or lower, or 770° C. or lower.

4. The strain rate during heavy working may be 0.001/s or more, 0.01/s or more, 0.1/s or more, or 1.0/s or more, and 10.0/s or less. It may be 0/s or less, or 3.0/s or less.

Although not bound by theory, it is believed that the following occurs inside the compact during severe working. The compact comprises a main phase 10 and grain boundary phases 20 existing around the main phase 10 (see FIG. 2). When the compact is severely worked, the main phase 10 is deformed. At this time, due to the deformation, at least some of the main phases 10 tend to have portions where the main phases 10 are in direct contact with each other. This contact portion can become a starting point for grain growth of the main phase 10 . If the strain rate during heavy working is slow, grain growth of the main phase 10 tends to occur starting from the contact portion. Since severe working is performed hot, a slow strain rate means that the aforementioned contact portion is at a high temperature for a long period of time. Then, atomic diffusion occurs through the contact portion, and grain growth of the main phase 10 occurs. On the other hand, in the initial stage of heavy working, Ce and La, especially La, are discharged from the main phase 10 to the grain boundary phase 20 . When the main phase 10 is deformed by discharge of Ce and La, Ce and La enter between the main phases 10, suppressing the formation of the aforementioned contact portion. Moreover, the melting point of the grain boundary phase 20 is lowered by the discharge of Ce and La. Strong working is performed at a temperature at which at least one of the grain boundary phases 20 melts. By lowering the melting point of the grain boundary phase 20, the viscosity of the melt of the grain boundary phase 20 during heavy working is reduced. As a result, the main phase 10 during deformation is easily rotated in the melt, and the main phase 10 is easily oriented in a specific direction. From these, when the strain rate is slow, typically, even when the strain rate is 0.001 / s or more and less than 0.01 / s, the grain growth of the main phase 10 is suppressed and the coercive force is suppressed, and the orientation of the main phase 10 is promoted to improve the magnetization. From this point of view, the strain rate may be 0.001/s or more and 0.008/s or less, or 0.001/s or more and 0.005/s or less.

The compressed body thus obtained may be used as it is as a rare earth magnet, or may be used as a rare earth magnet precursor for subsequent steps.

<Preparation of modifier>
A modifier containing an alloy having a composition represented by the formula R ² _z R ³ _w M ² _1-zw is prepared. The matters concerning R ² and R ³ and the matters concerning w are the same as those for the rare earth magnet.

M ² is an alloying element and an unavoidable impurity element that lowers the melting point of ^{R 2 z} _R ^{3 w} _M ² _1-zw below that of R ² by alloying with R 2 and R 3 . As a result, the alloy in the reforming material can be melted without excessively increasing the temperature of the heat treatment described later. As a result, the alloy in the modifier can permeate the rare earth magnet precursor without coarsening the structure of the rare earth magnet precursor. ^M2 may contain unavoidable impurity elements. An unavoidable impurity element is an impurity element such as an impurity element contained in a raw material, which cannot be avoided, or whose avoidance causes a significant increase in manufacturing cost.

^M2 is preferably one or more selected from Cu, Al, and Co and an unavoidable impurity element. This is because Cu, Al, and Co have little adverse effect on the magnetic properties and the like of rare earth magnets.

Examples of alloys having compositions represented by R ² _z R ³ _w M ² _1-zw include Nd--Cu alloys, Pr--Cu alloys, Nd--Pr--Cu alloys, Nd--Al alloys, Pr--Al alloys, Nd--Pr--Al alloy, Nd--Co alloy, Pr--Co alloy, Nd--Pr--Co alloy and the like.

The content ratio z of R ² will be explained. When z is 0.50 or more, the content of ^R2 in the alloy is large, so ^R2 easily penetrates into the main phase 10 and the intermediate phase 30. From this point of view, z is preferably 0.55 or more, more preferably 0.60 or more. On the other hand, if z is 0.80 or less, the melting point of the alloy in the modifier is properly lowered, so the temperature of the heat treatment described later becomes appropriate. As a result, coarsening of the structure of the rare earth magnet precursor can be suppressed. From the viewpoint of optimizing the melting point of the alloy, z is preferably 0.75 or less, more preferably 0.70 or less. As for z, when ^R2 is two or more elements, it is the sum of them. The same is true for ^M2 .

The method for producing the modifier is not particularly limited. Examples of the method for producing the reforming material include casting, liquid quenching, and the like. The liquid quenching method is preferable from the viewpoints that variations in the alloy components are small depending on the part of the modifier and impurities such as oxides are small.

The permeation amount of the alloy in the modifier is represented by t (atomic %) in the overall composition formula. The permeation effect of the modifier, such as improvement in magnetic properties, is recognized when t is 0.05 atomic % or more. As shown in FIG. 3, in order to clearly recognize the intermediate phase 30, t is preferably 0.1 atomic % or more, more preferably 1.0 atomic % or more, and 1.5 atomic %. The above is more preferable. On the other hand, since the modifier contains ^M2 , if the amount of permeation of the modifier becomes excessive, the magnetization of the rare earth magnet after the permeation of the modifier decreases. If t is 10.0 atomic % or less, the decrease in magnetization poses no practical problem. From this point of view, t is preferably 9.0 atomic % or less, more preferably 8.0 atomic % or less, and even more preferably 7.0 atomic % or less.

<Production of contact body>
A contact body is obtained by bringing the rare earth magnet precursor and the modifier into contact with each other. The rare earth magnet precursor is the compact as described above. At this time, at least one surface of the rare earth magnet precursor and at least one surface of the modifier are brought into contact with each other.

<Heat treatment>
The above-described contact body is heat-treated to allow the melt of the modifier to permeate the inside of the rare earth magnet precursor. As a result, the melt of the modifier reaches the surface of the main phase through the grain boundary phase of the rare earth magnet precursor, and the ^R2 in the modifier permeates the main phase to form an intermediate phase. .

The heat treatment temperature is not particularly limited as long as the modifier melts and the melt of the modifier can penetrate into the main phase of the rare earth magnet precursor.

The higher the heat treatment temperature, the easier it is for the modifier melt, especially ^R2 , to permeate the main phase of the rare earth magnet precursor. From this point of view, the heat treatment temperature is preferably 580° C. or higher, more preferably 600° C. or higher, and even more preferably 620° C. or higher. On the other hand, the lower the heat treatment temperature, the easier it is to suppress coarsening of the structure of the rare earth magnet precursor, particularly the main phase. From this point of view, the heat treatment temperature is preferably 800° C. or lower, more preferably 775° C. or lower, and even more preferably 725° C. or lower.

The heat treatment atmosphere is not particularly limited, but an inert gas atmosphere is preferable from the viewpoint of suppressing oxidation of the rare earth magnet precursor and modifier.

Hereinafter, the rare earth magnet of the present disclosure and the method for producing the same will be described more specifically with reference to examples. It should be noted that the rare earth magnet of the present disclosure and its manufacturing method are not limited to the conditions used in the following examples.

<Preparation of samples of Examples 1 to 26>
First, a rare earth magnet precursor is produced. A molten alloy having a composition represented by R _13.11 Fe _80.43 Cu _0.10 B _5.99 Ga _0.37 was liquid quenched by a single roll method to obtain a ribbon. R is as shown in Table 1-1 below. The liquid quenching conditions were a melt temperature (discharge temperature) of 1420° C. and a roll peripheral speed of 30 m/s. At this time, the cooling rate of the molten metal was 10 ⁶ K/sec. Liquid quenching was performed under an argon gas reduced pressure atmosphere. It was confirmed by observation with a transmission electron microscope (TEM) that the ribbon was nano-crystallized.

The thin strip was coarsely pulverized into powder, and the powder was charged into a die, pressurized and heated to obtain a compact. As the pressurization and heating conditions, the pressurization force was 400 MPa, the heating temperature was 650° C., and the pressurization and heating holding time was 60 seconds.

The compact was subjected to hot upsetting (strong hot working) to obtain a compressed body (plastically worked body). Intensive hot working compressed a sample with a height of 15 mm to 4.5 mm. The hot upsetting conditions were a working temperature of 780° C., a strain rate of 0.01/s, and a rolling reduction of 70%. Scanning electron microscopy (SEM) confirmed that the compact had oriented nanocrystals. This compressed body was used as a rare earth magnet precursor.

A Nd ₇₀ Cu ₃₀ alloy was produced as a modifier. Nd powder and Cu powder manufactured by Kojundo Chemical Co., Ltd. were weighed, arc-melted, and liquid-quenched to obtain a ribbon.

The rare earth magnet precursor and the modifier were brought into contact with each other and heat-treated in a heating furnace. The modifier amounts were 1.59 atomic %, 3.72 atomic %, and 5.32 atomic % relative to the rare earth magnet precursor (see Table 1-1). As the heat treatment conditions, the heat treatment temperature was 625° C., and the heat treatment time was 165 minutes.

<Preparation of sample of Comparative Example 1>
The composition of the alloy for making the rare earth magnet precursor is Nd _13.11 Fe _80.43 Cu _0.10 B _5.99 Ga _0.37 , and the modifier is impregnated into the rare earth magnet precursor. Samples were prepared as in Examples 1-26, except that there was no

<Preparation of samples of Examples 27 to 32>
Samples were prepared in the same manner as in Examples 1-26, except that the R of the rare earth magnet precursor was as shown in Table 1-3.

<Preparation of samples of Examples 33 to 36>
Samples were prepared in the same manner as in Examples 1 to 26, except that the R of the rare earth magnet precursor was as shown in Table 1-3 and that the modifier was not permeated into the rare earth magnet precursor.

<Preparation of samples of Examples 37 to 38>
The composition of the alloy for producing the rare earth magnet precursor is R _13.11 Fe _80.80 Cu _0.10 B _5.99 , and the R of the rare earth magnet precursor is as shown in Table 1-3. Samples were prepared in the same manner as in Examples 1 to 26, except for

<Example 39>
A sample was prepared in the same manner as in Example 6, except that the strain rate during hot upsetting of the compact was set to 0.001/s.

<Example 40>
A sample was prepared in the same manner as in Example 12, except that the strain rate during hot upsetting of the compact was set to 0.001/s.

<Preparation of sample of Comparative Example 2>
Samples were prepared in the same manner as in Examples 1-26, except that the composition of the alloy for making the rare earth magnet precursor was Nd _13.11 Fe _80.43 Cu _0.10 B _5.99 Ga _0.37 . made.

<Preparation of samples of Comparative Examples 3 to 7>
Samples were prepared in the same manner as in Examples 1-26, except that the R of the rare earth magnet precursor was as shown in Table 1-3.

<Preparation of sample of Comparative Example 8>
A sample of Comparative Example 8 was prepared in the same manner as in Comparative Example 1, except that the R of the rare earth magnet precursor was as shown in Table 1-3.

<Preparation of sample of Comparative Example 9>
A sample of Comparative Example 9 was prepared in the same manner as in Comparative Example 2, except that the R of the rare earth magnet precursor was as shown in Table 1-3 and that the permeation amount of the modifier was 3.72 atomic %. . The sample of Comparative Example 9 is equivalent to the sample of Comparative Example 8 in which 3.72 atom % of the modifier is permeated.

<Preparation of sample of Comparative Example 10>
A sample of Comparative Example 10 was prepared in the same manner as in Comparative Example 1, except that the R of the rare earth magnet precursor was as shown in Table 1-3.

<Preparation of sample of Comparative Example 11>
A sample of Comparative Example 11 was prepared in the same manner as in Comparative Example 2, except that the R of the rare earth magnet precursor was as shown in Table 1-3 and that the permeation amount of the modifier was 3.72 atomic %. . The sample of Comparative Example 11 is equivalent to the sample of Comparative Example 10 in which 3.72 atomic % of the modifier is permeated.

<Preparation of sample of Comparative Example 12>
A sample of Comparative Example 13 was prepared in the same manner as in Comparative Example 2, except that the R of the rare earth magnet precursor was as shown in Table 1-3 and the permeation amount of the modifier was 3.72 atomic %. .

<evaluation>
The samples of Examples 1-40 and Comparative Examples 1-12 were measured for coercive force and residual magnetization. For the measurement, a pulse excitation type magnetic property measuring device manufactured by Toei Industry Co., Ltd. (maximum applied magnetic field: 15 T) was used. Both coercivity and remanent magnetization were measured at 23°C, 100°C, 140°C and 160°C.

The results are shown in Tables 1-1 to 1-4 and Tables 2-1 to 2-2. Tables 1-1 and 1-3 also show the composition of each sample. Further, the gradient ΔHc between 23° C. and 160° C. for the coercive force and the gradient ΔBr between 23° C. and 160° C. for the residual magnetization are also shown. Table 2-1 also shows the hot upset conditions and the average grain size. Here, the average grain size means the average grain size t of crystal grains composed of the main phase 10 and the intermediate phase 30 (see FIG. 3). 4 is a graph showing the relationship between temperature and coercive force for the samples of Example 15 and Comparative Example 1. FIG. 5 is a diagram showing the relationship between temperature and residual magnetization for the samples of Example 15 and Comparative Example 1. FIG.

The samples of Examples 6, 12, 17, 39, and 40 were subjected to structural observation using a scanning transmission electron microscope (STEM) and component analysis (EDX-ray analysis).

Evaluation results are shown in FIGS. Among these, FIGS. 6 to 14 are the evaluation results for the examples and comparative examples shown in Tables 1-1 to 1-4, and FIGS. 15 to 26 are the evaluations for the examples shown in Tables 2-1 to 2-2. This is the result.

FIG. 6 is a diagram showing tissue observation and component analysis positions for the sample of Example 6. FIG. 7 is a diagram showing the results of structural observation and component analysis of the sample (first field of view) of Example 6. FIG. FIG. 8 is a diagram showing the results of structural observation and component analysis of the sample (second field of view) of Example 6. FIG. FIG. 9 is a diagram showing tissue observation and component analysis positions for the sample of Example 12. FIG. 10 is a diagram showing the results of structural observation and component analysis of the sample (first field of view) of Example 12. FIG. FIG. 11 is a diagram showing the results of structural observation and component analysis of the sample of Example 12 (second field of view). FIG. 12 is a diagram showing tissue observation and component analysis positions for the sample of Example 17. FIG. FIG. 13 is a diagram showing the results of structural observation and component analysis of the sample (first field of view) of Example 17. FIG. FIG. 14 is a diagram showing the results of structural observation and component analysis of the sample of Example 17 (second field of view).

FIG. 15 is a diagram showing an example of grain size t of crystal grains in the sample of Example 39. In FIG. FIG. 16 is a diagram showing an example of grain size t of crystal grains for the sample of Example 40. In FIG. FIG. 17 is a diagram showing an example of grain size t of crystal grains in the sample of Example 6. In FIG. FIG. 18 is a diagram showing an example of grain size t of crystal grains for the sample of Example 12. In FIG. The average grain size in Table 2 is the average grain size t of each crystal grain included in the field of view in each of FIGS.

19 is a diagram showing the tissue observation results and component analysis positions for the sample of Example 39. FIG. FIG. 20 is a diagram showing the results of component analysis at positions indicated by white lines in FIG. FIG. 21 is a diagram showing tissue observation results and component analysis positions for the sample of Example 40. FIG. FIG. 22 is a diagram showing the results of component analysis at positions indicated by white lines in FIG. 23 is a diagram showing the tissue observation results and component analysis positions for the sample of Example 6. FIG. FIG. 24 is a diagram showing the results of component analysis at positions indicated by white lines in FIG. 25 is a diagram showing the tissue observation results and component analysis positions for the sample of Example 12. FIG. FIG. 26 is a diagram showing the results of component analysis at positions indicated by white lines in FIG. In addition, Table 3 shows the peak concentrations of La and Ce in the grain boundary phase and The results of determining their total peak concentrations are shown.

From Tables 1-1 to 1-4, it was confirmed that all the samples of Examples 1-38 had smaller absolute values of ΔHc than those of Comparative Examples 1-4. Also, it was confirmed that the absolute value of ΔBr was very small for all the samples of Examples 1 to 38. Furthermore, in Comparative Examples 5 to 7, it was confirmed that the magnetization decreased significantly at high temperatures. From these results, it was confirmed that the rare earth magnet of the present disclosure can suppress a decrease in coercive force at high temperatures without significantly affecting magnetization. The same thing was confirmed in FIGS. 4 and 5 as well. Also, from FIGS. 6 to 11, the formation of the intermediate phase 30 could be confirmed.

Regarding the samples impregnated with the modifier, the samples of Examples 1 to 32 and Examples 37 to 38 and the samples of Comparative Examples 9, 11 and 12 are compared. Then, in the samples of Examples 1 to 32 and Examples 37 to 38 containing Nd, Ce, and La with respect to rare earth elements, Comparative Examples 9, 11, and 12 containing only Nd and La It was confirmed that the absolute value of ΔHc was smaller than in the sample of . The same was confirmed between the samples of Examples 33 to 36 and the samples of Comparative Examples 8 and 10 with respect to the samples in which the modifier was not permeated.

From Table 2, it was confirmed that even when the strain rate was slow, the increase in the average grain size of the crystal grains was suppressed, and as a result, the coercive force did not deteriorate. In addition, it was confirmed that the magnetization was improved when the strain rate was slow. Also, from Table 3, when the strain rate is slow compared to when the strain rate is fast, the concentrations of Ce and La, particularly La, in the grain boundary phase 20 are high, and the coercive force is maintained and the magnetization is improved. It has been confirmed that there is a high possibility that there is a high correlation with discharge of Ce and La from the main phase 10 to the grain boundary phase 20 .

From the above results, the effects of the rare earth magnet of the present disclosure and the method for producing the same have been confirmed.

10 main phase 20 grain boundary phase 30 intermediate phase 100 rare earth magnet (precursor)

Claims (11)

main phase and
a grain boundary phase existing around the main phase;
with
The overall composition has the formula (Nd _x (Ce, La) _(1-xy) R ¹ _y ) _p Fe _(100-pqr-s) Co _q B _r M ¹ _s (R ² _z R ³ _w M ² _1-zw ) _t ,
R ¹ is one or more selected from rare earth elements other than Nd, Ce, and La, R ² is one or more selected from Pr, Nd, Pm, Sm, Eu, and Gd, and R ³ is one or more selected from rare earth elements other than ^R2 , and ^M1 is one or more selected from Ga, Al, Cu, Au, Ag, Zn, In, and Mn, and unavoidable impurity elements and ^M2 is ^{an alloying} element and an unavoidable impurity element that lowers the _melting point of ^R2zR3wM21 _{- zw} below that of ^R2 by alloying with R2 ^{and R3} . Yes ,
p , q, r, s, and t in atomic %,
5.0≦p≦20.0,
0≤q≤8.0,
4.0≦r≦6.5,
0≦s≦2.0 and 0≦t≦10.0
and
x, y, z, and w, in molar ratios,
0.4≦x≦0.8,
0≤y≤0.1,
0.5≦z≦0.8 and 0≦w≦0.1
and
q, s, y, and w each being 0 means that Co _q , M ¹ _s , R ¹ _y , and R ³ _w are absent in the above formula ;
that t is 0 means that (R ² _z R ³ _w M ² _1-zw ) _t does not exist in the above formula ;
The La is contained in a molar ratio of 1/9 to 3 times that of the Ce , and
The average particle size of the main phase is 1 to 1000 nm,
Rare earth magnet. 2. The rare earth magnet according to claim 1, wherein said La is contained in a molar ratio of 1/9 to 2 times said Ce with respect to said Ce. Further comprising an intermediate phase between the main phase and the grain boundary phase,
wherein t is 0.1 ≤ t ≤ 10.0, and the concentration of ^R2 is higher in the intermediate phase than in the main phase;
A rare earth magnet according to claim 1 or 2. 4. A rare earth magnet according to claim 3 , wherein said ^R2 is Nd. A rare earth magnet according to claim 3 or 4, wherein the concentration of ^R2 is 1.5 to 8.0 times higher in said intermediate phase than in said main phase. A rare earth magnet according to any one of claims 3 to 5, wherein the thickness of said mesophase is 2 to 100 nm. Represented by the formula (Nd _x (Ce, La) _(1-xy) R ¹ _y ) _p Fe _(100-pqr-s) Co _q B _r M ¹ _s ,
R ¹ is one or more selected from rare earth elements other than Nd, Ce, and La; M ¹ is one or more selected from Ga, Al, Cu, Au, Ag, Zn, In, and Mn; and unavoidable impurity elements ,
p , q, r, and s in atomic %,
5.0≦p≦20.0,
0≤q≤8.0,
4.0≦r≦6.5 and 0≦s≦2.0
and
x and y, in molar ratio,
0.4≦x≦0.8 and 0≦y≦0.1
and
q 1 , s, and y each being 0 means that Co _q , M ¹ _s , and R ¹ _w are absent in the above formula, and
Preparing a molten metal containing 1/9 to 3 times the La in molar ratio with respect to the Ce;
quenching the molten metal to obtain a ribbon having a main phase with an average particle size of 1 to 1000 nm;
Hot compressing a plurality of ribbons to obtain a compact, and Hot compressing the compact to obtain a compact,
including,
A method for producing a rare earth magnet. 8. The method according to claim 7, wherein the molten metal contains La in a molar ratio of 1/9 to 2 times that of Ce. Represented by the formula R ² _z R ³ _w M ² _1-zw , R ² is one or more selected from Pr, Nd, Pm, Sm, Eu, and Gd, and R ³ is other than R ² is one or more rare earth elements selected from the group consisting of rare earth elements, and M ² makes the melting point of ^{R 2 z} _R ³ _w M ^{2 1} _-zw higher than the melting point of R ² by alloying with R 2 and R 3 It is an alloying element and an unavoidable impurity element that lowers, and z and w are 0.5 ≤ z ≤ 0.8 and 0 ≤ w ≤ 0.1 in molar ratio, and w is 0 , providing a modifier containing an alloy in which R ³ _w is absent,
Bringing the compressed body and the modified material into contact with each other to obtain a contact body, and heat-treating the contact body to allow the melt of the modified material to permeate the inside of the compressed body;
including,
9. A method according to claim 7 or 8. 10. The method of claim 9, wherein said ^R2 is Nd. The molded body is compressed at a strain rate of 0.001 / s or more and less than 0.01 / s, a rolling reduction of 50 to 70%, and a temperature of 700 to 800 ° C. to obtain a compressed body, claims 7- 11. The method of any one of 10.

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