JPH08316018A - Magnet and bonded magnet - Google Patents

Abstract

PURPOSE: To provide a low-cost magnet having high coercive force, high rectangular ratio and high energy product. CONSTITUTION: A magnet contains R (R is one or more types of rare earth elements, the Sm ratio in the R is 50 atomic % or more), T (Fe or Fe and Co), N and M (Zr or the part of Zr is substituted with one or more types of Ti, V, Cr, Nb, Hf, Ta, Mo, W, Al, C and P), wherein R amount is 4 to 8 atomic %, N amount is 10 to 20 atomic %, M amount is 2 to 10 atomic % and the residue is substantially T. In the magnet, there exists a hard magnetic phase containing R, T and N as main bodies and including one or more types of crystalline phases of TbCu7 type, Th2 Zn17 type and Th2 Ni17 type and soft magnetic phase made of T phase of bcc structure, wherein the mean crystalline grain size of the soft magnetic phase is 5 to 60nm, and the ratio of the soft magnetic phase is 10 to 60vol.%. With this structure, high coercive force is obtained, its rectangular ratio is high and high maximum energy product is realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to rare earth nitride magnets and bonded magnets.

[0002]

2. Description of the Related Art Sm-Co is a high-performance rare earth magnet.
System magnets and Nd-Fe-B system magnets have been put into practical use,
In recent years, new rare earth magnets have been actively developed.

For example, an Sm-Fe-N-based rare earth nitride magnet in which N is interstitially solid-dissolved in Sm ₂ Fe ₁₇ crystal has been proposed, and the composition near Sm ₂ Fe ₁₇ N _{2.3 is} 4πIs =
15.4 kG, Tc = 470 ° C., H _A = 14 T, basic physical properties are obtained, (BH) max of 10.5 MGOe is obtained as a metal-bonded magnet using Zn as a binder, and Sm ₂ Fe ₁₇ It was reported that the introduction of N into the intermetallic compound significantly improved the Curie temperature and improved the thermal stability (Paper No.S1.3 at theSixth
International Symposium on Magnetic Anisotropy and
Coercivity inRare Earth-Transition Metal Alloys, P
ittsburgh, PA, October 25,1990. (Proceedings Book: Car
negie Mellon University, Mellon Institute, Pittsburg
h, PA 15213, USA)).

The magnet particles used in the above-mentioned bonded magnet have a particle size of about a single crystal particle, and the coercive force generating mechanism thereof is a nucleation type. Therefore, the magnetic properties are easily affected by the surface state of the particles. In other words, defects occur on the surface of the magnet particles due to mechanical impact during crushing, particle oxidation, etc., and domain walls are generated by these defects, but in the case of a nucleation type magnet, there is no domain wall pinning site in the crystal grains, which facilitates Since the domain wall movement occurs in the magnetic field, the coercive force is likely to deteriorate.

Regarding the improvement of the rare earth nitride magnet, Japanese Patent Laid-Open No. Hei 3
No. 16102 discloses a two-phase separation type Re-Fe-N.
-HM type magnets are proposed. Re is a rare earth element, M is Li, Na, K, Mg, Ca, Sr, Ba,
Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W,
Mn, Pd, Cu, Ag, Zn, B, Al, Ga, I
n, C, Si, Ge, Sn, Pb, Bi elements and oxides, fluorides, carbides, nitrides, hydrides, carbonates, sulfates, silicates of these elements and rare earth elements,
At least one of chloride and nitrate. In the same publication, by adding M, a two-phase separation type microstructure such as that found in Sm-Co and Nd-Fe-B systems is formed, whereby a bulk magnet such as a sintered magnet or a bonded magnet is obtained. Sometimes, it aims to bring out the same high magnetic properties as powder. Specifically, M at the grain boundary
A bulk magnet of two-phase separation type is manufactured which has a phase having a large content of M and a small content of M in the center of the particle, or a phase not containing M. In this publication, a mother alloy is manufactured by a melting method, a liquid quenching method, or the like, the mother alloy is roughly pulverized, then hydrogenated, and then finely pulverized to obtain a sintered magnet or a bonded magnet. It is said that it is particularly effective to add M just before the fine pulverization.

Although the description of the publication is mainly made of sintered magnets, there is a description that it can be applied to bonded magnets. In the example of the publication, 8 mol% of Zn was added to Sm _8.9 Fe _75.4 N _15.5 H _0.2 alloy powder (particle size 20 to 38 μm), finely pulverized by a rotary ball mill, and then annealed at 430 ° C. for 1.5 hours. Then, a fine powder having a composition of Sm _8.2 Fe _69.5 N _14.3 H _0.05 Zn _8.0 is prepared, and a compression powder molding bonded magnet is produced using this fine powder. In the publication, since such a fine powder is used in manufacturing a bonded magnet, it is difficult to obtain stable magnet characteristics due to the influence of oxidation, and
There is also a problem that it is difficult to increase the density of magnets. Also, Sm
The ratio of Fe to Fe is Sm ₂ Fe ₁₇ (1
Since a large amount of Sm is used, which is almost equal to 0.5 atomic% Sm, it is difficult to reduce the cost.

In order to manufacture the Sm-Fe-N magnet at a low cost, it is effective to reduce the content of expensive rare earth elements. However, if the rare earth element content is reduced, Sm /
When (Sm + Fe) is 10 atomic% or less, α-
Since the precipitation of the Fe phase increases and the coercive force becomes extremely low, the stability as a magnet becomes insufficient.

[0008] J. Magn. Magn. Mater. 124 (1993) 1-4 reported a magnet prepared by using a mechanical alloy method and containing a rare earth element as small as 7 atom% and containing a small amount of Sm-Fe alloy. ing. This magnet consists of Sm ₂ Fe ₁₇ N _x phase and α-Fe
The coercive force is as low as about 3.9 kOe. Since the mechanical alloy method easily causes oxidation, it is difficult to industrially adopt it as a method for handling a metal that is easily oxidized, such as a rare earth element.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnet which is inexpensive, has a high coercive force, a high squareness ratio and a high maximum energy product.

[0010]

Such an object is achieved by any of the following constitutions (1) to (9). (1) R (R is at least one of rare earth elements, and S in R is
m ratio is 50 atomic% or more), T (T is Fe, or Fe and Co), N and M (M is Zr, or a part of Zr is Ti, V, Cr, Nb, Hf, T
a, Mo, W, Al, C and P are substituted with at least one element), R is 4 to 8 atom%, N is 10 to 20 atom%, and M is 2 10 to 10 atomic%, the balance is substantially T, R, T and N
Mainly, TbCu ₇ type, Th ₂ Zn ₁₇ type and Th
₂ has a hard magnetic phase containing at least one crystalline phase selected from Ni ₁₇ type, and a soft magnetic phase consisting of a T phase having a bcc structure, and the soft magnetic phase has an average crystal grain size of 5 to 60 nm. , A magnet in which the proportion of the soft magnetic phase is 10 to 60% by volume. (2) The magnet according to (1) above, wherein the squareness ratio Hk / iHc is 15% or more. (3) The magnet according to (1) or (2) above, which is manufactured by subjecting a quenched alloy manufactured by a liquid quenching method to a nitriding treatment. (4) The magnet according to (3) above, which is manufactured by a liquid quenching method with the surface speed of the cooling substrate relative to the molten alloy being 45 m / s or more. (5) The magnet according to the above (3) or (4), which is manufactured by subjecting a quenched alloy before nitriding treatment to a heat treatment for controlling the microstructure. (6) TbCu ₇ type, Th ₂ Zn ₁₇ type, and Th ₂ Ni ₁₇ are released by releasing hydrogen in the quenched alloy after heat treatment for controlling the structure of structure in an atmosphere containing hydrogen.
The magnet according to (5) above, which is produced by precipitating at least one crystal phase selected from the mold and a T phase having a bcc structure, and then subjecting it to a nitriding treatment. (7) The magnet according to (6) above, in which the quenched alloy before the heat treatment for controlling the microstructure has a TbCu ₇ type crystal phase. (8) The Sm ratio in R is 80 atomic% or more, the hard magnetic phase contains a TbCu ₇ type crystal phase, and in X-ray diffraction,
The maximum peak of the TbCu ₇ type crystal phase is 2θ = 42.00-
The magnet according to any one of (1) to (7) above, which is in the range of 42.50 °. (9) A bonded magnet containing the powder of the magnet according to any one of (1) to (8) and a binder.

[0011]

[Operation and effect] In the conventional Sm-Fe-N magnet,
When the rare earth element content was reduced, a large amount of α-Fe phase was precipitated and high coercive force could not be obtained. However, in the magnet of the present invention, the content of R mainly composed of Sm was reduced and then the element M was added. Add the above specified amount and add N amount within the above range (1
By setting it as 0 to 20 atomic%, it is possible to make the above-mentioned fine texture structure appear and obtain a high coercive force, and the squareness ratio is increased to improve the maximum energy product. The squareness ratio in this case means Hk / iHc. IH
c is a coercive force, and Hk is an external magnetic field strength when the magnetic flux density becomes 90% of the residual magnetic flux density in the second quadrant of the magnetic hysteresis loop. If Hk is low, a high maximum energy product cannot be obtained. Hk / iHc is an index of magnet performance and is the second parameter of the magnetic hysteresis loop.
Indicates the degree of squareness in the quadrant. Even if iHc is the same, the larger Hk / iHc, the sharper the distribution of the microscopic coercive force in the magnet, which facilitates the magnetization, reduces the variation in the magnetization, and increases the maximum energy product. Become. Then, the stability of the magnetization against the change of the demagnetizing field or the self-demagnetizing field from the outside when the magnet is used becomes good, and the performance of the magnetic circuit including the magnet becomes stable. With the magnet of the present invention, Hk / iHc of 15% or more can be easily obtained, and 18% or more, and even 20% or more can be obtained. Hk / iHc is usually about 45% or less. Further, as Hk, 1 kOe or more can be easily obtained, and it is possible to set it to 1.5 kOe or more, further 2 kOe or more. Hk is usually about 4 kOe or less. In the case of a bonded magnet, 20 to 20
It is possible to obtain Hk / iHc as high as 50%.

As described above, according to the present invention, it is possible to obtain a high coercive force, a high squareness ratio and a high maximum energy product while reducing the amount of expensive R used, so that a high-performance magnet can be realized at a low cost.

[0013] J. Magn. Magn. Mater. 124 (1993) 1-4 described above
Describes that the crystal grain size of the α-Fe phase after annealing was 20 to 55 nm, but the magnet described in the document does not contain the element M used in the present invention, and the α-Fe phase obtained by the mechanical alloy method is α-.
The Fe phase is formed. Therefore, it is considered that a high coercive force is not obtained even though the crystal grain size of the α-Fe phase is small.

There is also an example in which the element M used in the present invention is used in the above-mentioned Japanese Patent Laid-Open No. 3-16102, all of which are sintered magnets, and the structure of the magnet is also the present invention. Is different. Further, since the ratio of the rare earth element is almost equal to the stoichiometric composition, it is difficult to reduce the cost.

MAG-93-244 to 253 of the Institute of Electrical Engineers of Japan research report describes "magnetic properties of Sm-Fe-Co-V based nitride compounds and bonded magnets thereof". This bonded magnet is manufactured through the following steps. First, Sm ₂ (Fe _0.9 Co _0.1 ) _17-x V _x
(X = 0 to 2.0) alloy is melt-cast, and after solution treatment,
Grind to about 30 μm with a jaw crusher. Next, after nitriding, 3-5μ by jet mill
Finely pulverize to about m. Next, it is mixed with an epoxy resin binder and compression molded in a magnetic field to obtain a bonded magnet.

According to the report, Th ₂ Z at x = 0 to 1.0
It has an n ₁₇ type crystal structure, and has a TbCu ₇ type crystal structure at x = 1.5. In the X-ray diffraction chart of the powder after solution treatment, α- (Fe, C
Although the peak of (o) is not recognized, a peak of α- (Fe, Co) is recognized after the nitriding treatment under normal pressure, and this peak becomes smaller as x increases, and x = 1.
In No. 5, no α- (Fe, Co) peak is observed. From this, in the same report, V substitution has the effect of suppressing the precipitation of α- (Fe, Co). When x = 1.5 and the nitriding temperature was 600 ° C., the coercive force Hcj of the powder after fine pulverization was 256 kA / m (about 3.2 kOe),
This coercive force is not sufficient as a magnet material. In the same report, although the TbCu ₇ type phase is used, the R content is the same as the stoichiometric composition, and high coercive force is not obtained, and the fine bcc structure T like the present invention is used. There is no technical idea of improving coercive force by precipitating phases.

In JMEPEG (1993) 2,219-224, it was reported that a liquid quenching method was used and a coercive force exceeding 22 kOe was obtained by using a TbCu ₇ type phase. However, the composition of the alloy used in this report is Sm ₁₅ Fe _85, which is in excess of Sm over the stoichiometric composition Sm ₂ Fe ₁₇ , and does not contain the element M. That is, in the report, the technical idea of the present invention that an inexpensive and high-performance nitride magnet is obtained by reducing the R content and adding the element M is not found.

Japanese Unexamined Patent Publication (Kokai) No. 6-172936 discloses that R1 _x R2 _y A _z M _100-xyz (where R1 is at least one element selected from rare earth elements, and R2 has an atomic radius of 0.156 to At least one element selected from the elements having a thickness of 0.174 nm, A is at least one element selected from H, C, N and P, and M is Fe and Co.
Represents at least one element selected from x, y, z
Are atomic percentages of x ≧ 2, y ≧ 0.01, and 4 ≦ x + y, respectively.
≦ 20, 0 ≦ z ≦ 20), and the main phase is T
It has a bCu ₇ type crystal structure, and the M in the main phase is 90% of the total amount of all elements except A in the main phase.
A magnetic material is described which is at least atomic%. Also, M
20 atomic% or less of the total amount of T is T (T is Si, Ti, Al,
Ga, V, Ta, Mo, Nb, Cr, W, Mn and N
It is described that at least one element selected from i) can be substituted.

The magnetic material described in this publication is similar to the magnet of the present invention in that it has a TbCu ₇ type main phase, but in this publication, this main phase and a soft magnetic phase such as α-Fe phase coexist. The technical idea of the present invention to do so is not found, but there is only a description that the coercive force is remarkably lowered with the increase of the α-Fe phase. Further, in the magnetic material described in the publication, the proportion of Fe + Co in the main phase is as high as 90 atomic% or more, but this proportion exceeds the preferable range in the present invention. In the nitride magnet of the examples described in the publication, the rare earth element is not the main constituent of Sm, but the main constituent is Nd or Pr. In addition, the amount of nitrogen in the example of the nitride magnet is smaller than that in the present invention. Although a bonded magnet is manufactured in the embodiment described in the publication, the magnetic characteristics of this are significantly lower than those of the bonded magnet of the embodiment of the present invention.

Japanese Unexamined Patent Publication No. 6-342706 was published after the application of the basic application of the present application. In this publication, the general formula R _x A _z Co _y Fe _100-xyz (where R
Is at least one element selected from the group of rare earth elements,
A is at least one element selected from the group of H, N, C, and P, and x, y, and z are atomic%, and 4 ≦ x ≦ 2, respectively.
0, 0.01 ≦ y ≦ 20, z ≦ 20), the main phase has a TbCu ₇ type crystal structure, and Fe and Co in the main phase are A in the main phase. A magnetic material is described which is 90 atomic% or more of the total amount of all the elements except. Further, Fe is an M element (M is Ti, Cr, V, M
o, W, Mn, Ag, Cu, Zn, Nb, Ta, Ni,
It is described that at least one element selected from the group consisting of Sn, Ga and Al can be partially substituted.

The magnetic material described in this publication is similar to the magnet of the present invention in that it has a TbCu ₇ type main phase, but in this publication, this main phase and a soft magnetic phase such as α-Fe phase coexist. The technical idea of the present invention that it does is not found, and there is no description that Zr is added. Further, among the examples described in the publication, the nitrogen content of the nitride magnet is smaller than that of the present invention. In addition, the magnetic material described in the publication has the F in the main phase.
The ratio of e + Co is as high as 90 atomic% or more, but this ratio exceeds the preferred range in the present invention. Although a bonded magnet is manufactured in the embodiment described in the publication, the magnetic characteristics of this are significantly lower than those of the bonded magnet of the embodiment of the present invention.

Japanese Unexamined Patent Publication No. 6-330252 is published after the application of the basic application of the present application. In the same publication, in atomic%, Y, one or two or more kinds of rare earth metals (R) of lanthanide element, 2 to 7%, N 1 to 15%, balance F
A rare earth magnet material in the form of a powder, which is composed of e and has a two-phase metallographic structure of at least a hard magnetic rare earth compound phase and a soft magnetic iron phase, and each of the phases has a crystal grain size of 500 nm or less. And a portion of Fe is Z
can be replaced by r, the rare earth compound phase is Th ₂ Zn
It is described that it has a crystal structure of ₁₇ type, ThMn ₁₂ type or TbCu ₇ type.

The magnet material described in the publication is similar to the magnet of the present invention in that it has a hard magnetic phase and a soft magnetic phase, but the upper limit of the crystal grain size of the soft magnetic phase is 500 nm. Big compared to. It is only in Example 3 that the specific size of the soft magnetic phase is described in the publication. Example 3
The size of the soft magnetic phase of the magnet material is 10 to 50 nm,
It overlaps with the scope of the present invention. However, the composition of this magnet material is N
d _3.1 Fe _86.0 Ti _7. a ₈ N _3.1, Sm and Zr
Is not included, and the amount of N is below the range of the present invention. Moreover,
The hard magnetic phase of this magnet material is Th ₂ Mn ₁₂ , which is completely different from the magnet of the present invention. In other examples, there is no description of the specific size of the soft magnetic phase, and there is no example in which Zr is added. Also, in all the examples, the amount of N is 6
It is at most atomic%, which is below the range of the present invention. In the publication, there is a description that the magnet materials of these examples showed extremely high magnetic characteristics, but according to the experiments by the present inventors, high characteristics could not be obtained with these magnet materials. , The squareness ratio becomes insufficient.

Japanese Unexamined Patent Publication No. 6-279915 is published after the application of the basic application of the present application. The same publication, component composition represented by _{R x Fe 100- (x + y} + z) M y A z, the average powder particle diameter of 10 to 200 [mu] m, wherein R is Y, 1 kind of lanthanide element Or two or more rare earth metals, M is one or more of V, Ti and Mo, A is one or two of N and C, and x, y, z Is an atomic percentage in the following range 5 ≦ x ≦
A rare earth magnet material with 15, 1 ≦ y ≦ 20 and 1 ≦ z ≦ 25 is described. The publication does not mention that Zr is added to the magnet material, nor does it describe the soft magnetic phase. Regarding the crystal grain size, there is only a description that the crystal grains of the quenched ribbon were about 50 to 100 nm.

Japanese Unexamined Patent Publication No. 7-66021 is published after the application of the basic application of the present application. In this publication, the general formula R1 _x R2 _y A _z Co _u Fe _100-xyzu
(However, R1 is at least 1 selected from rare earth elements.
The seed element, R2, has an atomic radius of 0.156 to 0.174 nm
At least one element selected from the elements
At least one element selected from C, N, and P is shown, and x, y, z, and u are atomic% and 2 ≦ x and 0 ≦, respectively.
y, 4 ≦ x + y ≦ 20, 0 ≦ z ≦ 20, 0.01 ≦ y +
u)), the main phase has a TbCu ₇ type crystal structure, and the X-ray main diffraction peak intensity of the α-Fe phase or (FeCo) phase is 0.01 to 5 times that of the main phase. A permanent magnet is described. Then, as R2, Sc, Z
At least one element selected from the group of r and Hf is exemplified.

The magnet described in the above publication has a TbCu ₇ type main phase and an α-Fe phase, and is similar to the magnet of the present invention in that magnetic properties are improved by exchange coupling of both phases. However, the publication does not describe the ratio of the α-Fe phase. α-F
The ratio of the X-ray main diffraction peak intensities of the e phase and the main phase does not completely correlate with the volume ratio of the two, and for example, α-Fe
The volume ratio of the α-Fe phase in the permanent magnet described in the publication is unknown because it varies depending on the crystal grain size of the phase and the crystallinity. In both the bonded magnets (Table 3) using rapid cooling (peripheral speed 40 m / s) by the copper roll and the bonded magnets (Table 4) using mechanical alloying in the example of the same publication, the Zr content and N
Since the amount is below the range of the present invention, it is considered that the above-mentioned squareness ratio Hk / iHc becomes low, and therefore the maximum energy product becomes low. In fact, in Tables 3 and 4, the maximum energy product is remarkably low and the residual magnetic flux density is also low as compared with the examples of the present invention.

Japanese Unexamined Patent Publication No. 7-118815 is published after the application of the basic application of the present application. In this publication, the general formula R1 _x R2 _y A _z Co _u Fe _100-xyzu
(However, R1 is at least 1 selected from rare earth elements.
Element, R2 is at least one element selected from Zr, Hf and Sc, A is at least one element selected from C, N and P, and x, y, z and u are atomic% 2 ≦ x, 4 ≦ x + y ≦ 20, 0 ≦ z ≦ 2, respectively
0, 0 ≦ u ≦ 70), and the main phase is TbCu
TbCu in X-ray diffraction pattern (angular resolution 0.02 ° or less) having a _7- type crystal structure and using CuKα rays
_When the main reflection intensity of the _7- type phase is I _p and the main reflection intensity of the α-Fe phase is I _Fe , the half-value width of the main reflection intensity of the TbCu _7- type phase is 0.8 ° or less and I _Fe / ( I _Fe + I _p ) is 0.4
Permanent magnets containing the following magnetic alloys are described.

The permanent magnet described in the publication is similar to the magnet of the present invention in that it has a TbCu ₇ type main phase and an α-Fe phase. However, the publication does not describe the ratio of the α-Fe phase, and as described above, the volume ratio of both phases is obtained from the ratio of main reflection intensities I _Fe / (I _Fe + I _p ) in X-ray diffraction. It is not possible. In the example of the publication, since the amount of N is below the range of the present invention, the above-mentioned squareness ratio Hk / iH
It is considered that c becomes low, and therefore the maximum energy product becomes low. Further, in the bonded magnet utilizing the rapid cooling (peripheral velocity 40 m / s) by the copper roll of the embodiment of the same publication, the residual magnetic flux density is lower than that of the embodiment of the present invention.

[0029]

[Specific configuration]

<Structural Structure of Magnet> The magnet of the present invention has a composite structure containing R, T, N and M, and a hard magnetic phase as a main phase and a fine soft magnetic phase.

The hard magnetic phase is mainly composed of R, T and N,
It has at least one crystal structure selected from a hexagonal TbCu ₇ type, a rhombohedral Th ₂ Zn ₁₇ type, and a hexagonal Th ₂ Ni ₁₇ type, and nitrogen has penetrated into these crystal structures. It is a structure. The hard magnetic phase is usually TbCu ₇
Type crystal phase or Th ₂ Zn ₁₇ type crystal phase or these 2
Although the phases are mixed, when a rare earth element on the heavy rare earth side of Sm is included, a Th ₂ Ni ₁₇ type crystal phase may exist. R is mainly Th and Tb sites, T is mainly Zn, Ni and C sites
It is considered to exist in the u site, but part of T may exist in the Th site and the Tb site. Although it depends on the element, M is thought to be mainly present in the Zn site, Ni site and Cu site, but it may also be present in the Th site and Tb site. Also, M
May enter the bcc structure T phase which is a soft magnetic phase.

In the hard magnetic phase, the atomic ratio T / (R +
T + M) is preferably less than 90%, more preferably 75-87%. If T / (R + T + M) is too small, the saturation magnetization and residual magnetic flux density will be low, and if it is too large, the maximum energy product will be low.

The soft magnetic phase is a T phase having a bcc structure and is substantially an α-Fe phase, or a part of Fe in the α-Fe phase is replaced with Co, M, R or the like. Conceivable.

With the magnet of the present invention, a high coercive force is obtained when the average crystal grain size of the soft magnetic phase is 5 to 60 nm. There are a hard magnetic phase with high crystal magnetic anisotropy and a soft magnetic phase with high saturation magnetization in the magnet.Since the soft magnetic phase is fine, the interfaces between both phases increase and exchange anisotropy occurs. It is considered that a high coercive force can be obtained. If the average grain size of the soft magnetic phase is too small, the saturation magnetization will be low, and if it is too large, the coercive force and the squareness will be low. The average crystal grain size of the soft magnetic phase is preferably 5 to 40 nm, and when the hard magnetic phase has a TbCu ₇ type crystal structure, the magnet has a higher performance.

The soft magnetic phase is generally amorphous and can be confirmed by a transmission electron microscope. The average crystal grain size of the soft magnetic phase is calculated by image analysis of the magnet cross section.
First, for the soft magnetic phase contained in the measurement target region of the magnet cross section, the number n of crystal grains and the total cross-sectional area S of each crystal grain are calculated by image analysis. Then, the average cross-sectional area S / n per one crystal grain of the soft magnetic phase is calculated, and the diameter D of the circle having the area S / n is taken as the average crystal grain size. That is, the average crystal grain size D is obtained from the formula π (D / 2) ² = S / n. The measurement target area is preferably set so that n is 50 or more.

The average crystal grain size of the hard magnetic phase is preferably 5 to 500 nm, more preferably 5 to 100 nm. When the average crystal grain size of the hard magnetic phase is too small, the crystallinity is insufficient and it is difficult to obtain a high coercive force. On the other hand, when the average crystal grain size of the hard magnetic phase is too large, the time required for the nitriding treatment tends to be long. The average crystal grain size of the hard magnetic phase is calculated in the same manner as the average crystal grain size of the soft magnetic phase.

The ratio of the soft magnetic phase in the magnet is 10
-60% by volume, preferably 10-36% by volume. If the proportion of the soft magnetic phase is too low or too high, good magnet characteristics cannot be obtained, and especially the maximum energy product becomes low.
The proportion of the soft magnetic phase is determined by a so-called area analysis method using a transmission electron micrograph of the magnet cross section. In this case, the cross-sectional area ratio becomes the volume ratio.

<Reason for limiting composition of magnet> Next, the reason for limiting the composition of the magnet of the present invention will be described.

The content of R is 4 to 8 atom%, preferably 4
~ 7 atomic%. The content of N is 10 to 20 atomic%, preferably 12 to 18 atomic%, more preferably 15 atomic%.
It is more than 18 atomic% or less, and more preferably 15.5 to 18 atomic%. The content of M is 2 to 10 atom%, preferably 2.5 to 5 atom%. The balance is substantially T.

If the content of R is too small, the coercive force becomes low. On the other hand, if the content of R is too large, the amount of b-phase T-phase is reduced, resulting in poor magnet characteristics.
Since a large amount of is used, an inexpensive magnet cannot be obtained. R other than Sm is Y, La, Ce, P
r, Nd, Eu, Gd, Tb, Dy, Ho, Er, T
One or more of m, Yb, Lu and the like can be used. The hard magnetic phase of the magnet of the present invention is Th ₂ Zn ₁₇ type, Th ₂ N
Nitrogen is introduced into the i ₁₇ type and TbCu ₇ type crystal structures, and such hard magnetic phase exhibits the highest magnetocrystalline anisotropy when R is Sm. When the ratio of Sm is low, the crystal magnetic anisotropy is lowered and the coercive force is also lowered. Therefore, the Sm ratio in R is 50 atom% or more, preferably 70 atom% or more.

If the N content is too low, the Curie temperature, the coercive force, the squareness ratio, the saturation magnetization and the maximum energy product are insufficiently improved. The magnetic flux density tends to decrease, the squareness ratio decreases, and the maximum energy product also decreases. N
The content can be measured by a gas analysis method or the like.

The element M is added to realize the above-mentioned fine composite structure. If the element M is not contained, coarse crystal grains of the soft magnetic phase are precipitated during the production of the alloy, so that high coercive force cannot be obtained even if the average crystal grain size of the soft magnetic phase finally becomes relatively small. . If the content of M is too small, it becomes difficult to obtain a magnet having a small average grain size of the soft magnetic phase. On the other hand, when the content of M is too large, the saturation magnetization becomes low. M is Zr or a part of Zr is Ti, V, Cr, Nb, Hf, Ta, Mo, W,
It is substituted with at least one element selected from Al, C and P. As the element substituting Zr,
At least one of Al, C and P is preferred, especially A
1 is preferred. In the present invention, Zr is essential,
This is because it is particularly effective in controlling the tissue structure and also effective in improving the squareness ratio. Further, Al also has an effect of facilitating the nitriding of the quenched alloy, so that the time required for the nitriding treatment can be shortened by adding Al. Zr in the magnet
The content is preferably 2 to 4.5 atom%, more preferably 3 to 4.5 atom%. This is the same when using only Zr as M or when using it together with other elements. When the Zr content is low, neither high coercive force nor high squareness ratio can be obtained, and when the Zr content is too high, the saturation magnetization and the residual magnetic flux density become low.

The balance excluding the above elements is substantially T. T is Fe or Fe and Co. Although the addition of Co improves the characteristics, the ratio of Co in T is preferably 50 atomic% or less. When the ratio of Co exceeds 50 atomic%, the residual magnetic flux density becomes low.

[0043] If the hard magnetic phase of the magnet <X ray diffraction> The present invention includes the TbCu ₇ crystal phase, the maximum peak intensity of the TbCu ₇ crystal phase in X-ray diffraction using Cu-K [alpha line I _H When the maximum peak intensity of the soft magnetic phase is I _S , I _S / I _H is preferably 0.4 to 2.0, more preferably 0.7 to 1.8. I _S / I _H is 0.4
.About.2.0, a high squareness ratio is exhibited, and I _S / I _H is 0.
If it is 7 to 1.8, a higher squareness ratio can be obtained. I _S
If / I _H is too small or too large, the maximum energy product tends to be low.

In the manufacturing method described later, the quenched alloy is subjected to a heat treatment for controlling the structure of the structure to obtain a fine bcc structure T.
When precipitating a phase, I _S / I _H of the quenched alloy before heat treatment
Is preferably 0.4 or less, more preferably 0.25 or less. As described above, by reducing I _S / I _H immediately after quenching and increasing I _S / I _H by the heat treatment, that is, by promoting the precipitation of the bcc structure T phase by the heat treatment, a fine bcc structure T phase is obtained. Is easily dispersed in the tissue, and high magnet characteristics are easily realized.

When the Sm ratio in R is 80 atomic% or more, Tb in X-ray diffraction using Cu-Kα ray
The maximum peak of the Cu ₇ type crystal phase is 2θ = 42.00 to 4
It is preferably in the range of 2.50 °. If the position of the maximum peak deviates from the above range, it becomes difficult to obtain high characteristics. Specifically, the position of the maximum peak is 2θ = 42.
If it is less than 00 °, the residual magnetic flux density tends to decrease, and if it exceeds 2θ = 42.50 °, the Curie temperature increases, the coercive force improves, the squareness ratio increases, the saturation magnetization increases, and the maximum The energy product is insufficiently improved.

<Manufacturing Method> Next, a method suitable for manufacturing the magnet of the present invention will be described.

In this method, a quenching alloy containing R, T and M is manufactured by a liquid quenching method, and the quenching alloy is subjected to a nitriding treatment to be magnetized.

In the liquid quenching method, a molten alloy containing R, T and M is rapidly cooled to obtain a quenched alloy. The liquid quenching method used is not particularly limited, single roll method,
Although various methods such as a twin roll method and an atomizing method may be appropriately selected, it is usually preferable to use the single roll method because the mass productivity is high and the reproducibility of the quenching condition is good. The quenching condition in the case of using the single roll method is not particularly limited and may be appropriately set depending on the composition of the alloy so as to obtain a preferable microstructure, but usually Cu or C is used.
Using a cooling roll of u alloy, the roll peripheral speed is preferably 10 m / s or more, more preferably 30 m / s or more, further preferably 45 m / s or more, particularly preferably 55 m / s or more,
Most preferably, it is set to 65 m / s or more. By setting the roll peripheral speed to an appropriate value, the quenched alloy becomes close to a microcrystalline state or an amorphous state, and subsequent heat treatment makes it possible to achieve an arbitrary crystal grain size and facilitate nitriding. For this reason,
A magnet with high coercive force, high residual magnetic flux density, high squareness ratio and high maximum energy product can be obtained. The roll peripheral speed is usually 1
It is preferably 20 m / s or less. If the peripheral speed of the roll is too high, the molten alloy and the peripheral surface of the roll are poorly contacted with each other, so that heat transfer cannot be effectively performed. Therefore, the effective cooling rate becomes slow. Quenched alloys obtained by the single roll method are usually ribbon-shaped. The thickness of the ribbon is not particularly limited, but it is preferably 8 to 200 μm, more preferably 10 to 60 μm. It is difficult to produce a ribbon having a thickness of less than 8 μm, and it is difficult to obtain a sufficient cooling rate if the ribbon is too thick.

The structure of the quenched alloy is preferably a polycrystal having a substantially single phase or a fine composite structure, or a substantially amorphous phase. If the quenched alloy is polycrystalline, TbCu ₇ type, Th ₂ Zn ₁₇ type and Th ₂
Ni ₁₇ type, or a crystalline phase containing two or more of these types, and usually a T phase having a bcc structure,
It may also contain an amorphous phase. If the proportion of T-phase in the bcc structure is low or is substantially free of T-phase, the other crystalline phase is substantially TbCu ₇ type.

Bcc structure T having a predetermined average crystal grain size
In order to form a composite microstructure containing phases, the quenched alloy is usually subjected to a heat treatment for microstructure control. The treatment temperature in this heat treatment is preferably 400 to 800 ° C, more preferably 600 to 800 ° C, and the treatment time is usually about 0.1 to 300 hours, although it depends on the treatment temperature. This heat treatment is preferably performed in a non-oxidizing atmosphere such as an inert gas atmosphere, a reducing atmosphere, or in vacuum. By this heat treatment, a fine bcc structure T phase is precipitated, and
At least one crystal phase of Cu ₇ type, Th ₂ Zn ₁₇ type, and Th ₂ Ni ₁₇ type may be precipitated.

It is also preferable to perform the heat treatment for controlling the structure of the structure in an atmosphere containing hydrogen gas. In this heat treatment, the quenched alloy absorbs hydrogen to decompose the crystal containing R, T, and M into a T-phase with a bcc structure and an R hydride phase. The processing temperature at this time is preferably 350.
To 950 ° C., more preferably 500 to 800 ° C., and the treatment time is preferably 0.1 to 10 hours, more preferably 0.5 to 5 hours. The pressure of hydrogen gas in the atmosphere is preferably 0.1 to 10 atmospheres, and particularly preferably 0.5 to 2 atmospheres. The atmosphere at this time is not limited to hydrogen gas, but may be a mixed atmosphere of hydrogen gas and an inert gas. As the inert gas in this case, for example, He or Ar, or a mixed gas thereof can be used. Before heating to the decomposition temperature, 80 to 300
By occluding hydrogen for 0.1 to 1 hour, particularly 0.25 to 0.5 hour at 0 ° C, particularly 200 to 250 ° C, the subsequent decomposition reaction proceeds sufficiently and quickly.

After storing hydrogen, heat treatment is performed in a reduced pressure atmosphere to release hydrogen from the quenched alloy. By releasing hydrogen,
A composite structure containing at least one crystal phase of Th ₂ Zn ₁₇ type and Th ₂ Ni ₁₇ type and a fine T phase of bcc structure may be formed, and a TbCu ₇ type crystal phase may be formed.
The treatment temperature at this time is preferably 300 to 900 ° C.,
The treatment time is more preferably 450 to 850 ° C., and the treatment time is preferably 0.05 to 5 hours, more preferably 0.25 to 5 hours.
3 hours The pressure during treatment is preferably 1 × 10 ^-2
Torr or less, more preferably 1 × 10 ⁻³ Torr or less.
The heat treatment for releasing hydrogen is preferably performed subsequently to the heat treatment for absorbing hydrogen without lowering the temperature. As a result, high productivity can be obtained.

Such heat treatment using hydrogen gas is
It is particularly effective for a quenched alloy having a low ratio of bcc structure T phase or substantially free of bcc structure T phase.

After the heat treatment for controlling the structure of the structure, the quenched alloy is nitrided. In the nitriding treatment, the quenched alloy is heat-treated in a nitrogen gas atmosphere. By this treatment, TbCu ₇
Atoms penetrate into the crystals of the type, Th ₂ Zn ₁₇ type, and Th ₂ Ni ₁₇ type to form an interstitial solid solution, and become a hard magnetic phase. The treatment temperature during the nitriding treatment is preferably 350 to
The temperature is 700 ° C, more preferably 350 to 600 ° C, and the treatment time is preferably 0.1 to 300 hours. The pressure of nitrogen gas is preferably about 0.1 atm or higher. Note that high-pressure nitrogen gas, nitrogen gas + hydrogen gas, or ammonia gas can be used for the nitriding treatment.

The nitriding treatment is usually performed after crushing a ribbon-shaped, flaky-shaped or granular quenched alloy, but if uniform nitriding is possible, the nitriding treatment may be performed without crushing the quenched alloy.

There is no particular limitation on the shape of the magnet of the present invention, and it may be in the form of a ribbon or a grain. When applied to a magnet product such as a bonded magnet, it is pulverized to a predetermined particle size to obtain a magnet particle.

When applied to a bonded magnet, the average particle size of the magnet particles is usually preferably 10 μm or more, but in order to obtain sufficient oxidation resistance, the average particle size is preferably 30 μm or more, The thickness is preferably 50 μm or more, more preferably 70 μm or more.
Further, by setting the particle diameter to this level, a high density bonded magnet can be obtained. The upper limit of the average particle size is not particularly limited, but is usually about 1000 μm or less, preferably 250 μm or less. The average particle diameter in this case means the weight average particle diameter D ₅₀ obtained by sieving.
Means The weight average particle diameter D ₅₀ is the particle diameter when the total weight becomes 50% of the total weight of all particles by adding the weights from the particles having the smaller diameter.

The bonded magnet is produced by binding magnet particles with a binder. The magnet of the present invention can be applied to either a compression bonded magnet using press molding or an injection bonded magnet using injection molding. It is preferable to use various resins as the binder, but it is also possible to use a metal binder to form a metal-bonded magnet. The type of the resin binder is not particularly limited and may be appropriately selected from various thermosetting resins such as epoxy resin and nylon and various thermoplastic resins according to the purpose. The type of metal binder is also not particularly limited. Also, there are no particular restrictions on various conditions such as the content ratio of the binder to the magnet particles and the pressure during molding,
It may be appropriately selected from the usual range. However, in order to prevent the coarsening of the crystal grains, it is preferable to avoid methods requiring high temperature heat treatment.

[0059]

EXAMPLES The present invention will be described in more detail below by showing specific examples of the present invention.

<Example 1: Comparison by added element> Magnet powders shown in Table 1 below were prepared.

First, alloy ingots were manufactured by melting, and each ingot was crushed into small pieces. The obtained small pieces are put into a quartz nozzle and melted by high frequency induction heating to form a molten metal, which is rapidly cooled by a single roll method to have a thickness of about 30 μm and a width of 5 μm.
A ribbon-shaped quenched alloy of mm was used. Be-C for cooling roll
A u-roll was used and its peripheral speed was 50 m / s. As a result of observation by X-ray diffraction and a transmission electron microscope, it was confirmed that the quenched alloy had a polycrystalline composite structure containing a TbCu ₇ type crystal phase and a bcc structure α-Fe phase, and also contained an amorphous phase. .

Next, the quenched alloy was subjected to a heat treatment for controlling the structure of the structure in an Ar gas atmosphere. Heat treatment is 720
It was carried out at 0.5 ° C. for 0.5 to 1.5 hours. When X-ray (Cu-Kα-ray) diffraction and observation with a transmission electron microscope were performed after the heat treatment, a polycrystalline composite structure containing a TbCu ₇ type crystal phase and a bcc structure α-Fe phase was obtained, and the amorphous phase was It was virtually gone. Magnet powder No. 10
The X-ray diffraction chart after heat treatment of the quenched alloy used in No. 2 is shown in the uppermost stage of FIG.

Next, the crystallized alloy was pulverized to a diameter of about 150 μm or less and 450 ° C. in a nitrogen gas atmosphere of 1 atm.
Was subjected to nitriding treatment to obtain magnet powder. Table 1 shows the nitriding time of each magnet powder. Magnet powder after nitriding No. 1
The X-ray diffraction chart of No. 02 is shown in FIG. For reference, an X-ray diffraction chart when the nitriding treatment time is 10, 15 and 20 hours is also shown in FIG.

In FIG. 1, the crystal structure is maintained even after the nitriding treatment, but a shift of the peak of the TbCu ₇ type crystal phase to the lower angle side is recognized by the nitriding treatment. Therefore, it can be seen that the nitrogen atoms form an interstitial solid solution in the crystal lattice, and the crystal lattice expands.

[0065] Table 1 shows the I _S / I _H immediately after quenching of the magnet powder (before the thermal treatment), and I _S / I _H after the nitriding treatment. Further, after the nitriding treatment, the position of the maximum peak of the TbCu ₇ type crystal phase was examined, and this maximum peak was 2θ = 42.00-
When it was in the range of 42.50 °, it was marked with ◯, and when it was out of this range, it was marked with x.

The structure of each magnet powder was observed with a transmission electron microscope to determine the average crystal grain size of the α-Fe phase and the ratio of the α-Fe phase in the magnet powder. The results are shown in Table 1.
Shown in A transmission electron micrograph of magnet powder No. 102 is shown in FIG. In FIG. 2, high-concentration crystal grains are α-F.
It is the e phase.

The composition of these magnet powders, residual magnetic flux density (Br), coercive force (iHc), squareness ratio (Hk / iHc)
), The maximum energy product {(BH) m} was measured. The results are shown in Table 1.

[0068]

[Table 1]

From the results shown in Table 1, the effect of the present invention is clear. That is, in the magnet powder of the present invention containing the element M and having the average crystal grain size of the α-Fe phase in a predetermined range,
A high coercive force is obtained even if the R content is small. On the other hand, the magnetic powder No. 109 containing no M has a very small coercive force.

Further, from Table 1, the effect of making Zr essential as the additional element M is clear. That is,
When an element other than Zr is added alone, the squareness ratio is insufficient and the maximum energy product is extremely low. It is also found that when the N content is less than the range of the present invention, the squareness ratio is low and the maximum energy product is remarkably low. When the squareness ratio Hk / iHc is less than 15%, the magnetization changes greatly due to a slight change in the demagnetizing field from the outside or the self-demagnetizing field when the magnet is used, and the performance of the magnetic circuit including the magnet is stable. Will not do.

Further, about 60 hours were required for nitriding Sm ₂ Fe ₁₇ having a stoichiometric composition, but in the composition range of the present invention, the time required for nitriding can be reduced to about 1/3 or less. I understand. Then, it is understood that the nitriding treatment time can be further shortened by adding Al.

In the case of magnet powder No. 101 to 108, α
The grain sizes of the —Fe crystals were relatively uniform. On the other hand, in magnet powder No. 109, a large number of coarse α-Fe crystal grains were recognized and the grain size distribution was wide. In each of the magnet powders described above, the average crystal grain size of the TbCu ₇ type crystal phase as the main phase was about 10 to 100 nm. Further, when the T concentration T / (R + T + M) in the main phase was examined by a transmission electron microscope, it was in the range of 80 to 85%.

<Example 2: Comparison by R content and ratio of soft magnetic phase> Magnet powders having the compositions shown in Table 2 were prepared. The manufacturing conditions are 700 to 75 for heat treatment to control the microstructure.
Performed for 0.5 to 1 hour at 0 ℃, and after heat treatment about 80μm
The magnet powder was the same as each magnet powder of Example 1 except that the powder was pulverized to the following diameter and nitriding was performed for the time shown in the table.

The same measurements as in Example 1 were carried out on these magnet powders. Table 2 shows the results.

[0075]

[Table 2]

From Table 2, when the R content is 4 to 8 atomic% and the ratio of the soft magnetic phase is 10% by volume or more, particularly high residual magnetic flux density and maximum energy product are obtained, and the squareness ratio is also increased. I understand.

In each of the magnet powders, the average crystal grain size of the TbCu ₇ type crystal phase, which is the main phase, is about 10 to 10
It was 0 nm. Further, when the T concentration T / (R + T + M) in the main phase was examined by a transmission electron microscope, it was 80 to 85.
It was in the range of%.

<Example 3: Comparison by Sm ratio in R>
Magnet powders having the compositions shown in Table 3 were produced. The manufacturing conditions were the same as those for the magnet powders of Example 2.

The same measurements as in Example 1 were carried out on these magnet powders. The results are shown in Table 3.

[0080]

[Table 3]

From Table 3, it can be seen that high characteristics can be obtained when the Sm ratio in R is 50 atomic% or more.

In each of the magnet powders, the average crystal grain size of the TbCu ₇ type crystal phase, which is the main phase, is about 10 to 10.
It was 0 nm. Further, when the T concentration T / (R + T + M) in the main phase was examined by a transmission electron microscope, it was 80 to 85.
It was in the range of%.

<Example 4: Comparison by N content> Magnet powders having the compositions shown in Table 4 were prepared. The manufacturing conditions are those of Example 2.
However, the nitriding conditions were changed within the range of a processing temperature of 450 to 480 ° C. and a processing time of 1 to 20 hours.

The same measurements as in Example 1 were carried out on these magnet powders. The results are shown in Table 4.

[0085]

[Table 4]

From Table 4, the N content is 10 to 20 atomic%,
Especially 12 to 18 atom%, more than 15 atom% and 18 atom%
It can be seen that high characteristics, in particular high squareness ratio and high maximum energy product, are obtained when:

In each of the magnet powders, the average crystal grain size of the TbCu ₇ type crystal phase, which is the main phase, is about 10 to 10.
It was 0 nm. Further, when the T concentration T / (R + T + M) in the main phase was examined by a transmission electron microscope, it was 80 to 85.
It was in the range of%.

<Example 5: Comparison by Co content> Table 5
A magnet powder having the composition shown in was prepared. The manufacturing conditions were the same as those for the magnet powders of Example 2.

The same measurements as in Example 1 were carried out on these magnet powders. The results are shown in Table 5.

[0090]

[Table 5]

From Table 5, it can be seen that high characteristics can be obtained by adding an appropriate amount of Co.

In each of the magnet powders, the average crystal grain size of the TbCu ₇ type crystal phase, which is the main phase, is about 10 to 10
It was 0 nm. Further, when the T concentration T / (R + T + M) in the main phase was examined by a transmission electron microscope, it was 80 to 85.
It was in the range of%.

Example 6 Comparison by Average Particle Size of Soft Magnetic Phase Magnet powders having the compositions shown in Table 6 were prepared. The manufacturing conditions were the same as those of the magnet powders of Example 2, but the peripheral speed of the cooling roll was in the range of 5 to 80 m / s, and the heat treatment condition for controlling the structure of the structure was in the range of the processing temperature of 700 to 750 ° C. The treatment time was changed within the range of 0.5 to 5 hours.

The same measurements as in Example 1 were carried out on these magnet powders. The results are shown in Table 6.

[0095]

[Table 6]

From Table 6, the average particle size of the soft magnetic phase is 5-6.
It can be seen that high characteristics can be obtained at 0 nm, especially at 5 to 40 nm.

In each of the magnet powders, the average crystal grain size of the TbCu ₇ type crystal phase, which is the main phase, is about 10 to 10.
It was 0 nm. Further, when the T concentration T / (R + T + M) in the main phase was examined by a transmission electron microscope, it was 80 to 85.
It was in the range of%.

<Example 7: Comparison by manufacturing method> In the same manner as in Example 1, magnet powder No. 701 shown in Table 7 was prepared. For comparison, the magnetic powder No. 701 was prepared in the same manner as the magnet powder No. 701, except that the melt-casting method was used instead of the liquid quenching method, and the solution treatment was performed at 1100 ° C. for 16 hours after casting.
Magnet powder No. 702 was prepared. These magnet powders were observed and measured in the same manner as in Example 1. The results are shown in Table 7.

[0099]

[Table 7]

From Table 7, it is understood that when the melt casting method is used, coarse α-Fe crystal grains are deposited and a high coercive force cannot be obtained.

In the magnet powder No. 701, the average crystal grain size of the TbCu ₇ type crystal phase, which is the main phase, is about 10 to 10.
It was 100 nm. Moreover, when the T concentration T / (R + T + M) in the main phase was examined by a transmission electron microscope,
It was in the range of 85%.

<Example 8: Comparison by manufacturing method and crystal type> Magnet powders shown in Table 8 were prepared. First, Example 1
A quenched alloy was prepared in the same manner as in. However, the peripheral speed of the cooling roll was set to 40 m / s. The crystal phase of the quenched alloy is TbC
It was of the u ₇ type and no α-Fe phase was substantially observed. 70% quenched alloy in hydrogen gas atmosphere at 1 atm
Heat treatment at 0 ℃ for 1 hour, then 700 ℃ in vacuum
A dehydrogenation treatment was performed by heating at 1 hour. When X-ray diffraction was performed after the dehydrogenation treatment,
Formation of ₂ Zn ₁₇ type crystal phase and α-Fe phase was observed. After the dehydrogenation treatment, it was pulverized and nitrided in the same manner as in Example 1 to obtain a magnet powder. These magnet powders were observed and measured in the same manner as in Example 1. Table 8 shows the results.

[0103]

[Table 8]

From Table 8, it can be seen that a magnet powder having a high coercive force can be obtained by precipitating the α-Fe phase by heat treatment in hydrogen.

In each of the magnet powders, the average crystal grain size of the main phase Th ₂ Zn ₁₇ type crystal phase is about 10 to 1
It was 00 nm. Further, when the T concentration T / (R + T + M) in the main phase was examined by a transmission electron microscope, it was 80 to 8
It was in the range of 5%.

<Example 9: Combination of additional elements> Table 9
A magnet powder having the composition shown in was prepared. The manufacturing conditions were the same as those for the magnet powders of Example 2.

The same measurements as in Example 1 were carried out on these magnet powders. The results are shown in Table 9.

[0108]

[Table 9]

It can be seen from Table 9 that high characteristics can be obtained even when Zr and other elements are used in combination.

In each magnet powder, the average crystal grain size of the TbCu ₇ type crystal phase, which is the main phase, is about 10 to 10.
It was 0 nm. Further, when the T concentration T / (R + T + M) in the main phase was examined by a transmission electron microscope, it was 80 to 85.
It was in the range of%.

<Example 10: Bonded magnet> From the magnetic powders produced in the above examples, those having the compositions shown in Table 10 were selected, and magnetic powders having a relatively small average particle size were also produced. After mixing with epoxy resin,
A compression-bonded magnet was obtained by press molding and further heat treatment for curing. The epoxy resin was 2 to 3 parts by weight with respect to 100 parts by weight of the magnet powder. The pressure holding time during press molding is 10 seconds, and the applied pressure is 1
It was set to 0000 kgf / cm ² . The heat treatment for curing the resin was performed at 150 ° C. for 1 hour. The magnetic characteristics of these bonded magnets were measured in the same manner as in Example 1. The results are shown in Table 10.

[0112]

[Table 10]

It is understood that the bonded magnets shown in Table 10 are isotropic, but exhibit extremely high maximum energy products of 11 to 13 MGOe or more. Also, when the average particle size of the magnet powder is reduced to about 40 μm, Nd-Fe
Although the B-bonded magnet does not provide sufficient magnet characteristics, the present invention can provide a high-performance bonded magnet even when a small-diameter magnet powder is used. It is suitable.

The bonded magnets prepared by using magnet powders having a composition other than those shown in Table 10 also had magnetic characteristics corresponding to the magnetic characteristics of the magnet powders used.

<Example 11: Comparison by cooling roll peripheral speed> Magnet powder was produced by changing the peripheral speed of the cooling rolls, and their magnetic characteristics were investigated. Heat treatment after quenching is 600 ~
The optimum conditions were selected according to the cooling rate from the range of 750 ° C. for 1 to 2 hours, the nitriding treatment was performed at 450 ° C. for 10 hours, and the other conditions were the same as those of the magnet powder No. 110 including the composition. The results are shown in Fig. 3.

From FIG. 3, the peripheral speed of the cooling roll is 45 m / s.
It can be seen that particularly good magnetic properties are obtained in the above cases, and the coercive force becomes higher as the peripheral speed becomes faster.

The effects of the present invention are clear from the above examples.

[Brief description of drawings]

FIG. 1 is an X-ray diffraction chart of a quenched alloy after a heat treatment for structural structure control and an X-ray diffraction chart of a quenched alloy after a nitriding treatment.

FIG. 2 is a drawing-substitute photograph showing a crystal structure, which is a transmission electron microscope photograph of magnet powder.

FIG. 3 is a graph showing the relationship between the peripheral speed of the cooling roll and the magnet characteristics.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] September 26, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

The magnet material described in the publication is similar to the magnet of the present invention in that it has a hard magnetic phase and a soft magnetic phase, but the upper limit of the crystal grain size of the soft magnetic phase is 500 nm. Big compared to. It is only in Example 3 that the specific size of the soft magnetic phase is described in the publication. The size of the soft magnetic phase of the magnet material of Example 3 is 10 to 50 nm, which overlaps with the range of the present invention. However, the composition of this magnet material is Nd _3.1 Fe _86.0 Ti _7.8 N _3.1 ,
It does not contain Sm and Zr, and the amount of N is below the range of the present invention. Moreover, the hard magnetic phase of this magnet material is ThMn ₁₂
Which is completely different from the magnet of the present invention. In other examples, there is no description of the specific size of the soft magnetic phase, and
There is no example in which Zr is added. Further, the N content is 6 atomic% or less in all the examples, which is below the range of the present invention. In the publication, there is a description that the magnet materials of these examples showed extremely high magnetic characteristics, but according to the experiments by the present inventors, high characteristics could not be obtained with these magnet materials. , The squareness ratio becomes insufficient.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ryo Fukuno 1-13-1, Nihonbashi, Chuo-ku, Tokyo Inside TDC Corporation

Claims (9)

[Claims] 1. R (R is at least one of rare earth elements,
Sm ratio in R is 50 atomic% or more), T (T is F
e, or Fe and Co), N and M (M
Is Zr or a part of Zr is Ti, V, Cr, N
b, Hf, Ta, Mo, W, Al, C and P are substituted with at least one element), R is 4 to 8 atom%, N is 10 to 20 atom%. , M
Of 2 to 10 atomic%, the balance being substantially T, mainly composed of R, T and N, TbCu ₇ type, Th ₂ Zn
_At least 1 selected from the ₁₇ type and the Th ₂ Ni ₁₇ type
Having a hard magnetic phase containing a seed crystal phase and a soft magnetic phase composed of a T phase having a bcc structure, the soft magnetic phase having an average crystal grain size of 5 to 60 nm, and a soft magnetic phase ratio of 10 to 60. A magnet that is% by volume. 2. The magnet according to claim 1, wherein the squareness ratio Hk / iHc is 15% or more. 3. A quenched alloy produced by a liquid quenching method,
The magnet according to claim 1, which is manufactured by performing a nitriding treatment. 4. The magnet according to claim 3, which is produced by a liquid quenching method at a surface speed of the cooling substrate relative to the molten alloy of 45 m / s or more. 5. The magnet according to claim 3, which is manufactured by subjecting the quenched alloy before being subjected to the nitriding treatment to a heat treatment for controlling the microstructure. 6. A TbCu ₇ type, a Th ₂ Zn ₁₇ type and a Th type by releasing hydrogen in a quenched alloy after a heat treatment for controlling a structural structure in an atmosphere containing hydrogen.
_At least one crystalline phase selected from ₂ Ni ₁₇ type and b
The magnet according to claim 5, which is produced by precipitating a T phase having a cc structure and then subjecting it to a nitriding treatment. 7. The magnet according to claim 6, wherein the quenched alloy before the heat treatment for controlling the microstructure has a TbCu ₇ type crystal phase. 8. is a Sm ratio in R 80 atomic% or more, the hard magnetic phase comprises the TbCu ₇ crystal phase in X-ray diffraction, the TbCu ₇ maximum peak of the crystal phase is 2 [Theta] = 4
The magnet according to any one of claims 1 to 7, which is in the range of 2.00 to 42.50 °. 9. A bonded magnet containing the powder of the magnet according to claim 1 and a binder.