JP3370013B2 - Rare earth magnet material and rare earth bonded magnet using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to R-T-M (-
B) -N alloy (R is one or more rare earth elements including Y and always contains Sm, T is Fe or Fe and Co, M is Al, Ti, V, Cr, Mn, Cu, Ga,
Zr, Nb, Mo, Hf, Ta, W, and Zn), and is substantially free from a fine 2-17 type hard magnetic phase having very little or no αFe. And a high-performance isotropic rare earth bonded magnet using the same. Further, the present invention provides R-
The present invention relates to a rare earth magnet material which is a TM (-B) -N based alloy and R substantially consists of Sm and La, and an isotropic rare earth bonded magnet using the same, which has good magnetizability.

[0002]

2. Description of the Related Art Conventionally, rare earth bonded magnets containing Nd-Fe-B-based magnetic powder have been widely used. However, the Curie temperature is as low as around 300 ° C and the temperature coefficient of coercive force (iHc) is large, so that the temperature is high. The use of has been restricted. Recently, Sm
_{When the 2} Fe ₁₇ compound absorbs nitrogen, Nd ₂ Fe ₁₄
Since it has a higher Curie temperature (470 ° C.) and an anisotropic magnetic field (260 kOe) than the B compound, it is being industrialized as a magnetic powder for bonded magnets. But Sm
₂ Fe ₁₇ N _x cannot obtain a useful high iHc unless it is atomized to a single domain powder particle size (several μm). In the state of fine particles of several μm, they are easily oxidized in the atmosphere at room temperature and the magnetic characteristics are greatly deteriorated. At the same time, there is a problem that the filling property of the magnetic powder in the bonded magnet is deteriorated and the density of the isotropic bonded magnet is remarkably reduced, and it is difficult to realize a useful maximum energy product (BH) max.

In order to solve the above problems caused by atomization,
In Japanese Patent Laid-Open No. 260302/1992, after heat treatment in a hydrogen atmosphere, heat treatment in a reduced pressure atmosphere, and then nitriding, Sm is 5 to 15% in atomic% and M (M is Z
r, Hf, Nb, Ta, W, Mo, Ti, V, Cr, G
a, Al, Sb, Pb, at least one element selected from the group consisting of Si) 0 to 10% and N 0.5.
~ 25% content, balance Fe or Fe and Co (F
When the content of e is 20 atomic% or more) and M is included, a nitrided magnet powder having an average crystal grain size of 1 μm or less and an average powder grain size of 20 μm or more showing magnetic anisotropy is described. However, according to the study by the present inventors, the Japanese Patent Laid-Open No. 4-2
The nitride magnet powder produced according to the production conditions described in JP-A No. 60302 is magnetically isotropic and has an average crystal grain size of 1 μm.
It turned out to be over m. The cause of this is JP-A-4-26.
The hydrogen storage temperature described in the example of Japanese Patent No. 0302 is 650.
It was determined that the temperature was ℃ and the temperature was below the hydrocracking temperature.

Next, according to a study by the present inventors, a thin strip obtained by rapidly solidifying a melt of a mother alloy for rare earth nitride magnet materials with a peripheral speed of a quenching roll of, for example, 45 m / sec or more was used. -Applying the heat treatment conditions described in JP-A-260302,
By subsequent nitriding, it was possible to obtain a powder having an average powder particle size of 10 μm or more and an average crystal particle size of 1 μm or less. However, according to this manufacturing condition, the rapidly solidified thin strip exhibits a sharp shape, and the magnet powder finally obtained by nitriding has a poor compressibility due to the sharp shape of the thin strip. 6.1 g / cm ³ when used as a magnetic bond magnet
It turns out that it is difficult to achieve ultra high density. Therefore, improvement in (BH) max due to improvement in density can hardly be expected.

Next, magnetizing is an important characteristic of the isotropic rare earth bonded magnet, and it is desirable that the magnetizing magnetic field strength at room temperature be 25 kOe or less in practical use. However, conventional R-T-M
The -N-type isotropic rare earth bonded magnet has a problem that it has poor magnetizability when magnetized under the above conditions.

[0006]

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, an object of the present invention is to provide an R-T-M (-B) -N-based alloy (R is one or two rare earth elements containing Y). The above is always included, T is Fe or Fe and Co, and M is A
l, Ti, V, Cr, Mn, Cu, Ga, Zr, Nb,
One or more of Mo, Hf, Ta, W, and Zn), and has very little or no αFe.
(EN) A rare earth magnet material consisting essentially of a fine hard magnetic phase having a 2-17 type structure, and a high performance isotropic rare earth bonded magnet using the same. In addition, (Sm, L
a) a rare earth magnet material consisting of a fine hard magnetic phase of 2-17 type structure, which is a -TMM (-B) -N based alloy and contains very little or no αFe, and a It is an object of the present invention to provide an isotropic rare earth bonded magnet having good magnetizability.

[0007]

DISCLOSURE OF THE INVENTION The inventors of the present invention have made earnest studies on the rare earth nitride magnet powder and the isotropic rare earth bonded magnet using the same, by setting the following development goals. (1)
The average value of the area ratio shows that the rare earth nitride magnet particles are substantially 2
It is composed of a hard magnetic phase of -17 type structure, and αFe is preferably 5% or less, more preferably 2% or less, and particularly preferably 0% in terms of average area ratio. (2) Practical molding It is possible to easily form an isotropic rare earth bonded magnet by pressure, obtain a high density of more than 6.1 g / cm ³ , (3) have a heat resistance for practical use, and have (BH) max. 4) Must have improved magnetism for practical use. In focusing on these four points, for example, RT
-MN Nitride magnet alloy (R is one of rare earth elements including Y)
T is Fe or Fe and Co, M is Al, Ti, V, Cr, Mn, C
u, Ga, Zr, Nb, Mo, Hf, Ta, W, Zn) or a master alloy corresponding to the main component composition corresponding to the main component composition by a melting method, and then in a nitrogen-free inert gas atmosphere By homogenizing heat treatment at 1010 to 1280 ° C for 1 to 40 hours, then performing a hydrogenation / decomposition reaction treatment described below and a subsequent dehydrogenation / recombination reaction treatment, and subsequently performing nitriding, (1 ), (2) and (3) can be satisfied. However, in this case, it is necessary to carry out a homogenizing heat treatment, resulting in an increase in cost. Therefore, the present invention provides an R-T-M-B-N based nitride magnet alloy (R is one or more rare earth elements including Y and always contains Sm, T is Fe or Fe and C).
o and M are Al, Ti, V, Cr, Mn, Cu, Ga, Z
1 or 2 of r, Nb, Mo, Hf, Ta, W, Zn
The peripheral speed of the cooling roll in the melt quenching of the master alloy corresponding to the specific main component composition of at least one species and including Ti)
It is preferably 0.05 to 10 m / sec, more preferably 0.
Rapid solidification is carried out under the conditions of 08-9 m / sec, particularly preferably 0.1-8 m / sec. Next, after the hydrogenation / decomposition reaction treatment described below and the subsequent dehydrogenation / recombination reaction treatment are performed, nitriding is performed to perform (1), (2), (3 ) Was satisfied. Also,
It was found that it is effective to select a combination of Sm and La as R in order to improve the magnetizability.

[0008]

Means for Solving the Problems That is, according to the present invention, in atomic%, R _α T _{100- (α + β + γ + δ)} M _β B _γ N _δ (R is one or more rare earth elements including Y and Sm is Must contain, T is Fe or Fe and Co, M is Al, T
i, V, Cr, Mn, Cu, Ga, Zr, Nb, Mo,
One or more of Hf, Ta, W, Zn and Ti
Must be included, 6 ≦ α ≦ 15, 0.5 ≦ β ≦ 10, 0.1
≦ γ ≦ 4, 4 ≦ δ ≦ 30) and a peripheral speed of the cooling roll of 0.05 to 10 using a mother alloy having a main component composition represented by
The average crystal grain size is 0.01-
A rare earth magnet material for an isotropic bonded magnet, which is substantially composed of a hard magnetic phase having a 1-17 μm 2-17 type structure and has an average area ratio of αFe of 5% or less. By applying the present invention, it is possible to obtain a nitrided magnet powder without αFe even without performing homogenizing heat treatment. Next, when the content of the M element is 5 atomic% or more, the hard magnetic phase is a rhombohedral crystal having a Th ₂ Zn ₁₇ type structure and Th ₂ Ni.
A mixed crystal with a hexagonal crystal having a _17- type structure is obtained. Also,
R consists of Sm, La and unavoidable impurities,
The magnetizability is improved when the La content is 0.05 to 1% in atomic%. If the La content is less than 0.05 atom%, the magnetizability is not improved, and if it exceeds 1%, the squareness (Hk) is decreased. Anisotropy field (Ha) at the specific La content
And the saturation magnetic flux density (Bs) is slightly lowered, but (BH) of an isotropic bonded magnet magnetized at room temperature of 25 kOe or less.
The max and Hk can be increased. Hk is 4πI-
The value of H at the position of 0.7 Br on the H demagnetization curve, which is a measure of the rectangularity of the demagnetization curve. Br is the residual magnetic flux density, H is the magnetic field strength, and 4πI is the magnetization strength.

The rare earth magnet material powder preferably has a one-peak particle size distribution and an average particle size of 10 to 300 μm. Usually, unless two or more kinds of powders having different particle size distributions are mixed, one peak particle size distribution is obtained. The average particle size is 10μ
When it is less than m, deterioration of oxidation and deterioration of moldability become remarkable,
If it exceeds μm, a non-uniform nitriding structure is formed and the magnetic properties deteriorate.

An isotropic rare earth bonded magnet is formed by binding the rare earth magnet material powder with a resin. In particular, the binder resin is a thermosetting resin, and if a heat curing treatment is performed after the compression molding, a density of more than 6.1 g / cm ³ can be obtained. The conditions for heat curing are preferably 100 to 200 ° C. and 0.5 to 5 hours in the air or an inert gas atmosphere. 10
If it is less than 0 ° C. × 0.5 hours, the polymerization reaction of heat curing is insufficient, and if it exceeds 200 ° C. × 5 hours, the effect of heat treatment is saturated. In particular, when heat curing is performed in an Ar gas atmosphere (B
H) max can be increased, which is preferable.

In the rare earth magnet material, R is Sm.
Must be included, and in addition to Sm, Y, La, Ce, Pr, Nd,
Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, L
It is acceptable to include one or more of u. A mixture of two or more kinds of rare earth elements such as Sm misch metal and didymium may be used. As R, preferably S
m in combination with one or more of La, Y, Ce, Pr, Nd, Gd, Dy, Er, and more preferably Sm and one of La, Y, Ce, Pr, Nd or A combination of two or more kinds, particularly preferably a case of substantially only Sm or Sm and La. In terms of Sm purity, in order to obtain useful iHc,
The Sm ratio in R is preferably 50 atom% or more, and more preferably 70 atom% or more. In addition, R is mixed with O, H, C, Al, Si, Na, Mg, and
Inclusion of inevitable impurities such as Ca is allowed.

The R content is preferably 6 to 15 atomic%. R
Is less than 6 atomic%, iHc decreases, and if it exceeds 15 atomic%, the saturation magnetization (σ) decreases. A more preferable R content is 7 to 12 atomic%.

If the main component composition of the mother alloy containing a specific amount of M elements and B elements including Ti and the above-mentioned melt quenching conditions are adopted, a mother alloy without αFe can be obtained without carrying out solution heat treatment. To be In this case, M containing Ti in atomic%
The content (β) of the element is 0.5 to 10%, more preferably 1 to 6%, particularly preferably 1 to 4%, and T
The content of i must be 0.5 atomic% or more. Ideally, the M element should be composed of Ti and inevitable impurities. When performing solution heat treatment, B and Ti are not essential. In this case, the content (β) of the M element is atom% as described above, preferably 0.5 to 10 atom%, more preferably 1 to 6 atom%, and particularly preferably 1 to 4%.
When the M element exceeds 10 atomic%, ThMn ₁₂ type Sm (Fe,
M) ₁₂ N _z phase is generated to deteriorate the magnetic properties, and even if the M element (Ti) is less than 0.5 atomic%, the magnetic properties are deteriorated.
The B content (γ) is preferably 0.1 to 4 atom%. If the above-mentioned melt quenching conditions are adopted and homogenizing heat treatment is not performed, B
If the content is less than 0.1 atom%, iHc is significantly reduced,
If it exceeds 4 atomic%, iHc and σ decrease. Nitrogen content is 4
-30 atom% is preferable, and 10-20 atom% is more preferable. When the nitrogen content is less than 4 atom% or more than 30 atom%, iHc and σ are greatly reduced. Also, Co and /
Alternatively, Ni is preferably used to replace 0.5 to 30 atomic% of Fe, more preferably 1 to 20 atomic%. The introduction of Co and / or Ni improves the Curie temperature and the temperature coefficient (η) of iHc,
If the amount of substitution exceeds 30 atomic%, iHc and σ decrease significantly,
If it is less than 0.5 atom%, the effect of addition is not recognized. The rare earth magnet material having an average powder particle size of 10 to 300 μm can realize a high iHc, and thus has an oxygen content of 0.25.
It can be suppressed to less than or equal to weight%. Further, the content of carbon, which is an αFe forming element, is suppressed to 0.1% by weight or less, which is preferable for reducing αFe.

The average crystal grain size of the hard magnetic phase is 0.01 to 1
High magnetic properties can be obtained at μm. In industrial production,
It is difficult to stably produce a material having a thickness of less than 0.01 μm, and iHc is significantly reduced when the thickness exceeds 1 μm. Identification of the hard magnetic phase and αFe and calculation of the area ratio are performed by comprehensively considering the observation result by an electron microscope and / or an optical microscope and, if necessary, the X-ray diffraction result. For example, it can be determined by matching the transmission electron microscope photograph of the cross section of the target nitride magnet particle and the identification result of the cross section structure.

As the binder of the isotropic bonded magnet of the present invention, a resin, a rubber material, or a metal (alloy) having a melting point lower than the Curie temperature of the rare earth magnet material can be used. Of these, thermosetting resins, thermoplastic resins or rubber materials are practical, and compression molding methods, injection molding methods, extrusion molding methods, or molding methods for obtaining a sheet-shaped molded body by passing a compound between rotating rolling rollers are used. Can be adopted. When the compression molding method is used, a thermosetting resin is preferable, and a thermosetting liquid resin is particularly suitable. As a specific example, liquid resin such as epoxy resin, polyimide resin, polyester resin, phenol resin, fluororesin, silicon resin or polyphenylene sulfide resin (PPS) can be used. Liquid epoxy resins are the best because they are inexpensive, easy to handle and exhibit good heat resistance.

The manufacturing conditions of the rare earth magnet material of the present invention will be described below. First, the peripheral speed of the molten metal quenching roll is set in the above-mentioned specific range and rapidly solidified to obtain an Sm-Fe-Ti-B based master alloy corresponding to the main component of the nitrided magnet powder. When a non-quenching solidification melting method (high-frequency melting method, atomizing method, arc melting method, or the like) is used, homogenizing heat treatment is required to reduce αFe. The homogenization heat treatment is 1010 to 1280 ° C x 1 in an inert gas atmosphere containing no nitrogen.
Since heating is performed for 40 hours, not only the cost becomes disadvantageous, but also compositional deviation due to evaporation of Sm or the like becomes remarkable during heating, and it is difficult to stabilize the characteristics, but the present invention saves the step. be able to. Next, a hydrogenation / decomposition reaction treatment of heating at 675 to 900 ° C. for 0.5 to 8 hours in 0.1 to 10 atm of hydrogen gas or an inert gas (excluding nitrogen gas) having a hydrogen gas partial pressure is performed. , Then 1 × 10 ^-2
700-900 ° C x 0.5-in high vacuum below Torr
A dehydrogenation / recombination reaction treatment of heating for 10 hours is performed. The hydrogenation / decomposition reaction decomposes the mother alloy into a hydride RHx of the rare earth element R, a TM phase, and the like. Next, by a dehydrogenation / recombination reaction, the mother alloy phase is recombined to obtain a mother alloy composed of fine recrystallized grains having an average crystal grain size of 0.01 to 1 μm. The individual recrystallized grains are usually randomly oriented, but anisotropy can be imparted by the combination of the M elements. If the hydrogen partial pressure of the hydrogenation / cracking reaction is less than 0.1 atm, the cracking reaction hardly occurs, and if it exceeds 10 atm, the processing equipment becomes large and the cost increases. Therefore, the hydrogen partial pressure is 0.
1-10 atm is preferable and 0.5-5 atm is more preferable. If the heating conditions for the hydrogenation / cracking reaction are less than 675 ° C (corresponding to the hydrogenolysis temperature) x 0.5 hours, the mother alloy only absorbs hydrogen and does not decompose into RHx, TM phase, etc. If the temperature exceeds 8 hours, the mother alloy after dehydrogenation becomes coarse and iHc of the nitrided magnet powder is greatly reduced. Therefore, the heating conditions for the hydrogenation / decomposition reaction are 675 to 900 ° C.
0.5 to 8 hours is preferable, 675 to 800 ° C. × 0.5
~ 8 hours is more preferred. If the hydrogen partial pressure of the dehydrogenation / recombination reaction is lower than 1 × 10 ⁻² Torr, it takes a long time to process, and if the vacuum is higher than 1 × 10 ⁻⁶ Torr, the cost of the vacuum exhaust device will increase. . If the heating conditions of the dehydrogenation / recombination reaction are less than 700 ° C. × 0.5 hours, decomposition of RHx and the like does not proceed, and if it exceeds 900 ° C. × 10 hours, the recrystallized structure becomes coarse and iHc is greatly reduced. Therefore, in order to set the average recrystallized grain size to 0.01 to 1 μm, the heating conditions for the dehydrogenation / recombination reaction are preferably 700 to 900 ° C. × 0.5 to 10 hours, and 725 to 875 ° C. × 0.5. 10 hours is more preferable. Next, the rare earth magnet material powder of the present invention can be manufactured by pulverizing if necessary and then nitriding. It is preferable to adjust the particle size distribution by classifying or sieving as needed before nitriding in order to realize a uniform nitriding structure and to improve the moldability and density of the bonded magnet. Nitriding is a mixed gas of nitrogen gas of 0.2 to 10 atm, hydrogen of 1 to 95 mol% and the balance of nitrogen (hydrogen + nitrogen), and mol% of NH ₃ of 1 to 50% and balance of hydrogen ( Gas nitriding, which heats in an atmosphere of a mixed gas of (NH ₃ + hydrogen) in 300 to 650 ° C. for 0.1 to 30 hours, is highly practical. The heating conditions for gas nitriding are 300
~ 650 ° C x 0.1 to 30 hours are preferred, 400 to 5
50 ° C. × 0.5 to 20 hours is more preferable. 300 ° C ×
If it is less than 0.1 hours, nitriding does not proceed, and if it exceeds 650 ° C. × 30 hours, RN and Fe-M phase are conversely produced and iHc is lowered. The pressure of nitrogen alone gas or nitrogen-containing gas in nitriding is preferably 0.2 to 10 atm, and 0.5 to 5 atm.
Is more preferable. If it is less than 0.2 atm, the nitriding reaction is very slow, and if it exceeds 10 atm, the cost is increased due to the high pressure gas equipment. After nitriding, in vacuum or in an inert gas (excluding nitrogen gas) 300 to 600 ° C x 0.5 to 50
If heat treatment is performed for a long time, iHc may be further increased. The rare earth magnet material powder may contain 0.01 to 10 atomic% of hydrogen.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these Examples. (Example 1) Using Sm, Fe, Ti and B having a purity of 99.9% or more, Nos. Each was mixed with a mother alloy composition corresponding to the rare earth nitride magnet powders 1 to 7 and melted in a high frequency melting furnace in an argon gas atmosphere. This master alloy melt was rapidly solidified by a twin roll type strip caster equipped with two copper cooling rolls having a diameter of 300 mm and rapidly solidified under the condition that the peripheral speed of the quenching roll was 1.0 m / sec. Got A typical cross-sectional photograph of this master alloy ribbon is shown in FIG. In FIG. 4, voids and crystal grain boundaries were observed, but αFe was not generated. Next, the mother alloy ribbon was subjected to a hydrogenation / decomposition reaction treatment by heating in 1 atm of hydrogen gas at 680 ° C. for 1 hour. Then hydrogen partial pressure (in vacuum)
A dehydrogenation / recombination reaction treatment was carried out by heating at 800 ° C. for 1.5 hours at 5 to 8 × 10 ⁻² Torr. Next, in an argon gas atmosphere, an average powder particle size (dp) of 10 to 300 μm was crushed using a jaw crusher and a disc mill. For the measurement of dp, a laser diffraction type particle size distribution measuring device (HELOS / RODOS) manufactured by Sympatec was used. next,
450 crushed powders of each dp in 1 atm of nitriding gas
Nitriding was performed by heating at ℃ × 10 hours and cooled. After that, heat treatment was performed at 400 ° C for 30 minutes in an argon gas stream.
No. Rare earth nitride magnet powders 1 to 7 were obtained. No. 1
Table 7 shows the average crystal grain size (dc) of the hard magnetic phase of each rare earth nitride magnet powder, the saturation magnetization (σ) measured at 25 ° C, and the iHc temperature coefficient (η) at 25 to 100 ° C. Shown in 1. No. of Table 1 FIG. 8 shows a particle size distribution (single peak distribution) of the nitride magnet powder of No. 2 by HELOS / RODOS. In FIG. 8, the horizontal axis is the particle size x (μm), the left vertical axis is the ratio of cumulative volume distribution, and the right vertical axis is (q3l
g) = differential value defined by d (q3) / d (lnx). (Q3lg) is used to determine whether or not there is a one-peak particle size distribution. For measurement of iHc and σ, after mixing each rare earth nitride magnet powder and paraffin wax at a constant ratio, the mixture was packed in a copper container of a vibrating sample magnetometer (VSM) and sealed, and then this container was heated and cooled. The paraffin wax is melted and solidified to fix the nitrided magnet powder, and VSM
Set to. Subsequently, σ and iHc were measured at 25 ° C. in the atmosphere, corrected with only the nitride magnet powder. Then 100 ° C
Σ and iHc were measured by VSM in the state of being heated to.
From these measurement results, iHc at 25 to 100 ° C.
The temperature coefficient (η) of η = [iHc (25 ° C) -iHc
(100 ° C.)] / IHc (25 ° C.) × 100 (%). Next, No. Each of the nitride magnet particles 1 to 7 was embedded in a resin, and an arbitrary 5 fields of view of the polished cross section were subjected to electron diffraction using a transmission electron microscope. as a result,
It was found that any of the nitride magnet particles is composed of a hard magnetic phase having a 2-17 type structure having a rhombohedral hard magnetic phase having a Th ₂ Zn ₁₇ type structure as a main phase. αFe was not observed. dc is No. It was determined from a cross-sectional photograph of each nitrided magnet particle in a visual field that matches each electron diffraction result of 1 to 7. A specific measurement example of dc will be described later. Comparative Example 1 A rare earth nitride magnet powder was prepared and evaluated in the same manner as in Example 1 except that dp = 2 and 400 μm. The results are shown in Table 1. 11 and 12 are shown. (Comparative Example 2) No. 21 and 22, Ti
No. with a low content 23 and an excessive number. Table 1 shows the results of evaluation performed in the same manner as in Example 1 except that the composition of 24 rare-earth nitride magnet powders was used as the main component composition.

[0018]

[Table 1]

From Table 1, No. 1 of Example 1 is shown. In 1 to 7, the dc of the hard magnetic phase is less than 0.4 μm, σ is 120 (emu / g) or more, iHc is 9 kOe or more, and the temperature coefficient (η) of iHc is −0.40 (% / ° C.). ), And it has good heat resistance. These good magnetic properties have Ti content of 0.5 to 10 atomic% and dp
= 10 to 300 μm. On the other hand, Comparative Example 1
No. In No. 11, because of oxidative deterioration, and in No. 12, the nitriding structure is more inhomogeneous than that of Example 1, and therefore, σ
And iHc were low and η was bad. No. 2 of Comparative Example 2 containing no Ti. Nos. 21 and 22, No. 2 having a small Ti content.
No. 23 and Ti content are excessive. In No. 24, coarse αFe having an average crystal grain size of more than 1 μm was produced in an average area ratio of more than 5%, iHc was low, and η was poor. No. containing no Ti. A representative cross-sectional photograph of the master alloy ribbon of the nitrided magnet powder of No. 21 is shown in FIG. In FIG. 5, coarse αFe having an average crystal grain size of more than 1 μm was observed in a black dendritic form, and the average value of the area ratio was more than 5%. αF
It was confirmed that e exists without disappearing until after nitriding.

(Example 2) In order to check the correlation between the B content and the magnetic characteristics, the number of No. 2 in Table 2 was determined. Nitride magnet powder was produced in the same manner as in Example 1 except that the main component composition of the rare earth nitride magnet powders 31 to 34 was selected and dp = 80 μm was set.
evaluated. The results are shown in Table 2. 31-34. (Comparative Example 3) As shown in Table 2, N having a low B content
o. No. 41 and B having an excessive B content. No. 42 in Table 2 shows the evaluation results of the nitrided magnet powder prepared in the same manner as in Example 1 except that the main component composition was No. 42. 41 and 42.

[0021]

[Table 2]

No. 2 in Table 2 From 31 to 34, when the B content is 0.1 to 4 atomic%, dc = 0.01 to 0.33
μm, and good σ, iHc, and η were obtained. No.
The magnetic property manifesting phase of the nitride magnet particles 31 to 34 substantially consisted of a rhombohedral crystal having a Th ₂ Zn ₁₇ type structure, and αFe was not generated. On the other hand, Comparative Example 3 No. Four
The average crystal grain size of each of the 1 and 42 nitride magnet particles is 1
Coarse αFe of more than μm was produced in an average value of the area ratio of more than 5%, iHc was low, and η was poor. No. B with a small B content. A representative cross-sectional photograph of the master alloy ribbon of the nitrided magnet powder of No. 41 is shown in FIG. In FIG. 6, coarse αFe having a black dendritic average crystal grain size of more than 1 μm is produced in an average area ratio of more than 5%, and it is confirmed that αFe remains without disappearing until nitriding. Was done.

R content, type of R component, nitrogen content, M
Examples in which the type and content of elements are changed and a part of Fe is replaced with Co and / or Ni will be described below. (Example 3 and Comparative Example 4) Table 3 shows the results of evaluation and evaluation of the nitride magnet powder prepared in the same manner as in Example 1, except that the main component composition of the rare earth nitride magnet powder shown in Table 3 was used.

[0024]

[Table 3]

In Table 3, it was confirmed that each nitrided magnet particle of Example 3 was composed of a fine hard magnetic phase of 2-17 type structure without αFe. Next, No. 51-5
No. 3 of Comparative Example 4 and Comparative Example 4. From 71 to 73, it is found that good σ, iHc and η are obtained when the Sm ratio in the R component is 50 atomic% or more and the R component is 6 to 15 atomic%. Next, in No. 3 of the third embodiment. 54 and 55 and No. 4 of Comparative Example 4. From 74 and 75, it is found that good σ, iHc, and η are obtained when the nitrogen content is 4 to 30 atomic%. Next, in No. 3 of the third embodiment. From 56 to 59, it can be seen that η is improved by replacing 0.5 to 30 atomic% of Fe with Co and / or Ni. Next, in No. 3 of the third embodiment. It can be seen from 60 and 61 that good σ, iHc, and η can be obtained when the content of Ti in M is 0.5 atomic% or more.

Next, an example of measuring the dc of the hard magnetic phase of the rare earth magnet material of the present invention will be described. N in Table 2 (Example 2)
o. 33 Nitride magnet particles were embedded in resin and then polished to d
1 is a representative photograph of a sample for c measurement taken by a transmission electron microscope in arbitrary 5 fields of view of the cross section of the sample, and FIG. 1 is an explanatory diagram of the measurement procedure of dc in FIG. 2 shows. Diagonal lines are drawn on each of the cross-sectional photographs for five fields of view typified by FIG. 1, and the line segment length occupied by crystal grains existing on each diagonal line is divided by the number of the crystal grains, dc1 and dc2.
I asked. In FIG. 1, dc of diagonal evaluation from the upper left to the lower right
1 = 0.16 μm, dc2 of diagonal evaluation from upper right to lower left
= 0.15 μm was obtained. Similarly, dc1 and dc2 of each of the cross-sectional photographs for 5 fields of view were determined, and the average was dc = 0.16 μm. Next, using a transmission electron microscope, No. 1 in Table 1 (Example 1) was used. Sectional result of electron beam diffraction of 7 nitride magnet particles, _Th 2 Ni in FIGS. 3 (a)
An electron beam diffraction pattern showing the presence of a hexagonal crystal with a ₁₇ type structure and an electron beam diffraction pattern showing the presence of a rhombohedral crystal with a Th ₂ Zn ₁₇ type structure of FIG. 3B were obtained. FIG. 3A is an electron beam diffraction pattern photographed by injecting an electron beam from the [001] direction, and FIG. 3B is an electron beam diffraction pattern photographed by injecting an electron beam in the [100] direction. is there. Further, as a result of comprehensively considering the results of X-ray diffraction and optical microscope observation performed in parallel, No. Nitride magnet particles of No. 7 are Th ₂ Zn ₁₇ type rhombohedral crystals and Th ₂ N
It was identified to consist of a hard magnetic phase of a mixed crystal with a hexagonal crystal having an i ₁₇ type structure. αFe was not observed.

(Example 4) Sm and F having a purity of 99.9%
Compatible with the following rare earth nitride magnet powders using e, Ti, and B
After mixing with the master alloy composition,
The melt was melted and the peripheral speed of the quenching roll was set to 9.5 m / sec.
The molten alloy was solidified under quenching conditions to obtain a master alloy ribbon. next,
The mother alloy thin strip was charged into an atmosphere heat treatment furnace and 1 atm
While supplying the hydrogen gas of
Repeat the process of dehydrogenation by collecting and then applying a vacuum.
Coarse pulverization was performed to obtain an average powder particle size of 100 μm. next,
Set the hydrogen gas pressure for hydrogenation / cracking reaction to 1 atm, and
The hydrogenation / cracking reaction treatment was performed under the heating conditions of No. 4. continue
Hydrogen partial pressure is 5-8 × 10^-2Torr, and in Table 4
The dehydrogenation / recombination reaction treatment was performed under heating conditions. afterwards,
Nitrogen gas flow of 1 atm in another atmosphere heat treatment furnace
Perform nitriding by heating at 460 ℃ for 7 hours and cool to room temperature.
I rejected it. Subsequently, in an argon gas stream, 400 ° C x 30 minutes
Heat treatment was performed for a period of time and cooled to room temperature. Prepared rare earth nitride
Atomized magnet powder is Sm in atomic%_9.2Fe _bal.B
_1.0Ti_6.0N_12.3Having a main component composition of
Substantially consisting of a hard magnetic phase of 2-17 type structure αF
e was not observed. Thereafter, the evaluation is performed in the same manner as in Example 1.
Table 4 shows the evaluated dc, σ, and iHc. (Comparative Example 5) Hydrogenation / decomposition reaction and dehydrogenation / regeneration of Table 4
In the same manner as in Example 4 except that the heating conditions for the binding reaction were used.
Table 4 shows the results of the evaluation and evaluation of the nitrided magnet powder.

[0028]

[Table 4]

From Example 4 in Table 4, the heating conditions for the hydrogenation / cracking reaction were 675 to 900 ° C. × 0.5 to 8 hours, and the heating conditions for the dehydrogenation / recombination reaction were 700 to 900 ° C. ×
By setting the time to 0.5 to 10 hours, dc became less than 1 μm, and high σ and iHc were obtained. On the other hand, No. 1 below the hydrogenation / decomposition reaction temperature was used. 91, the hydrogenation / decomposition reaction temperature is too high. 92, the dehydrogenation / recombination reaction temperature is too low. 93, the dehydrogenation / recombination reaction temperature is too high. In all of 94, dc exceeded 1 μm.

(Embodiment 5) To evaluate the properties of the bonded magnet, αFe was not produced, and dc = 0.2 to 0.3 μm.
Each d in Table 5 consisting essentially of the 2-17 type hard magnetic phase of m
2 wt% of an epoxy resin was mixed with each rare earth nitride magnet powder of p and kneaded to prepare a compound.
Next, compression molding was carried out at a pressing pressure of 10 ton / cm ² , and heat curing heat treatment was carried out at 140 ° C. for 1 hour in the atmosphere to obtain an isotropic bonded magnet. 25 ° C, magnetizing magnetic field strength 25k
IHc of each isotropic bonded magnet measured by Oe, (BH)
Table 5 shows the temperature coefficient (η ') and density (ρ) of iHc of the bonded magnet at max 25 to 100 ° C. The temperature coefficient (η ′) of iHc of the bonded magnet is 25 ° C., iHc is measured at a magnetic field strength of 25 kOe, and then iHc is measured at 100 ° C. and a magnetic field strength of 25 kOe. (25 ° C) -iHc of bonded magnet (100 ° C)]
÷ [iHc of bonded magnet (25 ° C)] x 100 (%). (Comparative Example 6) The peripheral speed of the cooling roll in the molten metal quenching method was set to 4
At 5 m / sec, the melt of the mother alloy corresponding to the main component composition of the rare earth nitride magnet powder of Comparative Example 6 shown in Table 5 was rapidly solidified to obtain flakes, and thereafter, in the same manner as in Example 1, the rare earth of Table 5 was prepared. Nitride magnet powder was produced. Next, an isotropic bonded magnet was prepared in the same manner as in Example 5, and the evaluation results are shown in Table 5.

[0031]

[Table 5]

From Table 5, the isotropic bonded magnets of Example 5 all have a density of more than 6.1 g / cm ^{3 and} have a density of 8.0 MGO.
A high (BH) max of e or more was obtained. This is because the nitrided magnet powder used in Example 5 is nitrided using the mother alloy rapidly solidified at the peripheral speed of the molten metal quenching roll of 0.05 to 10 m / sec. It can be said that a particle having a rounded shape was exhibited and a higher density could be realized as compared with the No. 6 sample.

Next, an example in which the magnetizability is improved will be described. (Example 6, Comparative Example 7) Sm and L having a purity of 99.9% or more
Using a, Fe, Ti, and B, they were each compounded into a master alloy composition corresponding to the nitrided magnet powder shown in Table 6. Next, each mother alloy melt melted in a high frequency melting furnace in an argon gas atmosphere was cooled by a twin roll type strip caster equipped with two cooling rolls made of copper having a diameter of 300 mm, and the peripheral speed of the cooling roll was 0.5 m / sec. The alloy alloy ribbon was obtained by rapid solidification under the conditions. ΑFe was not formed in each mother alloy. Next, each master alloy ribbon was 675 ° C. in 1 atm of hydrogen gas.
A hydrogenation / decomposition reaction treatment is performed by heating for 1 hour, and subsequently at a hydrogen partial pressure (in vacuum) of 3 to 6 × 10 ⁻² Torr at 790 ° C.
A dehydrogenation / recombination reaction treatment of heating for 1.5 hours was performed. Next, it was pulverized in an argon gas atmosphere to a dp of about 80 μm. Next, 440 ° C x 1 in 1 atm of nitriding gas
A nitriding treatment of heating for 0 hours was performed and the resulting mixture was cooled. Then, heat treatment was performed at 400 ° C. for 30 minutes in an argon gas stream to obtain each rare earth nitride magnet powder shown in Table 6. Using each of the nitrided magnet powders in Table 6, an isotropic bonded magnet was manufactured thereafter in the same manner as in Example 5, and evaluated at 25 ° C. and a magnetic field strength of 25 kOe.
Table 6 shows (BH) max and Hk. In addition, No. 12
No. 2 (Example 6) and No. 5 in Table 5. (BH) max of the 101 (Example 5) isotropic bonded magnet with respect to the magnetizing magnetic field strength.
Is shown in FIG. 7A, and Hk with respect to the magnetic field strength is shown in FIG.
It shows in (b).

[0034]

[Table 6]

No. in Table 5 From the results of 121 and Table 6, L
It can be seen that (BH) max and Hk are improved when magnetized at 25 kOe when the a content is 0.05 to 1 atomic%.

Next, an example of the Sm (-La) -Fe-M-N based nitride magnet powder will be described. Reference Example 1 and Comparative Example 8 Sm, Fe and M elements having a purity of 99.9% or more were used to mix the respective master alloy compositions corresponding to the respective nitrided magnet powders in Table 7 and then high frequency melting was performed to form the master alloy. Obtained. Next, homogenization heat treatment was performed at 1100 ° C. for 10 hours in an argon gas atmosphere. Next, dp = 200 in an argon gas atmosphere.
It was crushed to ˜210 μm. Next, a hydrogenation / decomposition reaction treatment is performed by heating at 680 ° C. for 1 hour in 1 atm of hydrogen gas, and subsequently, hydrogen partial pressure (in vacuum) 5 to 8 × 10 ⁻² Tor.
A dehydrogenation / recombination reaction treatment was performed by heating at 800 ° C. for 1 hour. Next, in an argon gas atmosphere, using a jaw crusher and a disc mill, dp = 80 to 85 μm
Crushed into Next, each pulverized powder was subjected to a nitriding treatment of heating at 440 ° C. for 10 hours in a nitriding gas of 1 atm, and was cooled. Then, heat treatment was performed at 400 ° C. for 30 minutes in an argon gas stream to obtain each nitrided magnet powder shown in Table 7. ΑFe was not generated in each of the nitride magnet powders in Table 7, and dc =
The hard magnetic phase had a 2-17 type structure of 0.4 to 0.5 μm. After that, an isotropic bonded magnet was produced and evaluated in the same manner as in Example 5. The results are shown in Table 7.

[0037]

[Table 7]

In Table 7, No. 1 of Reference Example 1 was used. 141 ~
143 and Comparative Example 8. From 161, 162, T
It can be seen that when the i content is 0.5 to 10 atomic%, high iHc, (BH) max and η'that can be practically used can be obtained. In addition, No. From 144 to 155, it can be seen that high iHc, (BH) max and η ′ that can be practically used can be obtained even when a predetermined amount of M element other than Ti is contained.

(Reference Example 2 and Comparative Example 9) Sm, La, Fe and Ti having a purity of 99.9% or more were used and compounded into the mother alloy composition corresponding to the nitrided magnet powder shown in Table 8. Next, a master alloy was obtained by melting in a high frequency melting furnace in an argon gas atmosphere. Thereafter, a nitride magnet powder was produced in the same manner as in Reference Example 1, and subsequently an isotropic bonded magnet was produced, and the magnetizability was evaluated. The results are shown in Table 8.

[0040]

[Table 8]

From Table 8, it was confirmed that even if B was not contained, the effect of improving the magnetizability by containing La was confirmed.

In Reference Examples 1 and 2, a mother alloy produced by the high frequency melting method was used. Instead of this, a predetermined amount of metal Ca is added to a mixed raw material containing a rare earth oxide compounded in a main component composition corresponding to the rare earth nitride magnet material of the present invention, and a reaction product is obtained after reduction / diffusion. Extract and R-T-M
A rare earth magnet material powder of the present invention is obtained by obtaining a (-B) type master alloy and thereafter performing homogenization heat treatment, hydrogenation / decomposition reaction treatment, dehydrogenation / recombination reaction treatment, and nitriding similar to those in Reference Example 1. You may produce. In that case, in order to increase (BH) max, the Ca content is 0.1% by weight or less, and the oxygen content is 0.
It is preferable that the carbon content is 25% by weight or less and the carbon content is 0.1% by weight or less. Further, with respect to the R-T-M (-B) -based master alloy produced by the atomizing method or the arc melting method,
The rare earth magnet material powder of the present invention may be produced by performing the same homogenization heat treatment, hydrogenation / decomposition reaction treatment, dehydrogenation / recombination reaction treatment, and nitriding as in Reference Example 7. Further, for the mother alloy ribbon obtained by the molten metal quenching method of Example 1, thereafter, the same homogenization heat treatment, hydrogenation / cracking reaction treatment, and the like as in Reference Example 1 were performed.
The rare earth magnet material powder of the present invention may be produced by performing dehydrogenation / recombination reaction treatment and nitriding.

Each of the rare earth magnet material powders in the above examples has an oxygen content of 0.1% by weight or less and a carbon content of 0.
It is less than 1% by weight. For this reason, it is judged that high magnetic characteristics that can withstand practical use are obtained and that it contributes to the reduction of αFe. Further, in the above-mentioned examples, the case of the compression-molded isotropic bonded magnet is described. For example, a compound for injection molding or extrusion molding is produced by using the nitride magnet powder and a thermoplastic resin (polyamide resin etc.). Then, if injection or extrusion molding is performed by a predetermined molding device, an isotropic injection molded product or extrusion molded product can be obtained.

[0044]

EFFECTS OF THE INVENTION (1) R-T-M (-B) -N type alloys containing very little or no αFe.
It is possible to provide a rare earth magnet material substantially composed of a fine hard magnetic phase having a 2-17 type structure and a high-performance isotropic rare earth bonded magnet using the rare earth magnet material. (2) R-T-M (-B) -N based alloy, where R is Sm
It is possible to provide a rare earth magnet material consisting essentially of La and La, and an isotropic rare earth bonded magnet having good magnetizability using the rare earth magnet material.

[Brief description of drawings]

FIG. 1 is a transmission electron micrograph showing an example of a cross-sectional structure of a rare earth magnet material of the present invention.

FIG. 2 is a diagram illustrating a procedure for measuring the average crystal grain size in FIG.

Shows the results of electron diffraction by transmission electron microscope cross-section of a rare earth magnet material of the present invention; FIG, Th ₂ N
An electron beam diffraction pattern (a) showing the presence of a hexagonal crystal having an i ₁₇ type structure and an electron beam diffraction pattern (b) showing the presence of a rhombohedral crystal having a Th ₂ Zn ₁₇ type structure.

FIG. 4 is a photograph showing an example of a cross-sectional structure of a mother alloy used for the rare earth magnet material of the present invention.

FIG. 5 is a photograph showing a cross-sectional structure of a master alloy of a comparative example.

FIG. 6 is a photograph showing a cross-sectional structure of a master alloy of a comparative example.

FIG. 7 shows a magnetic field strength and B of an isotropic bonded magnet.
FIG. 4A is a diagram showing a relationship with r, and FIG. 4B is a diagram showing a relationship between magnetizing magnetic field strength and Hk.

FIG. 8 is a diagram showing an example of single-peak particle size distribution of the rare earth magnet material of the present invention.

─────────────────────────────────────────────────── ───Continuation of front page (56) References JP-A-4-260302 (JP, A) JP-A-4-142703 (JP, A) JP-A-8-316018 (JP, A) JP-A-7- 197102 (JP, A) JP-A-63-155601 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01F 1/00-1/117 B22F C22C

Claims (8)

(57) [Claims] 1. R _α T _{100- (α + β + γ + δ) in} atomic%
M _β B _γ N _δ (R is one or two of rare earth elements including Y)
T is Fe or Fe and C, which is more than one species and always contains Sm
o and M are Al, Ti, V, Cr, Mn, Cu, Ga, Z
1 or 2 of r, Nb, Mo, Hf, Ta, W, Zn
At least one species and always contains Ti, 6 ≦ α ≦ 15, 0.5 ≦
using a master alloy have a main component composition represented by β ≦ 10,0.1 ≦ γ ≦ 4,4 ≦ δ ≦ 30), the peripheral speed of the cooling roll
Of the hard magnetic phase having a 2-17 type structure having an average crystal grain size of 0.01 to 1 μm, and an average value of the area ratio of αFe is 5
% Or less, a rare earth magnet material for an isotropic bonded magnet . 2. The rare earth magnet material according to claim 1, wherein R is composed of Sm, La and unavoidable impurities, and the La content is 0.05 to 1% in atomic%. 3. A rare earth magnet material according to claim 1 or 2 hard magnetic phase consists of a mixed crystal of hexagonal rhombohedral and _Th 2 _{Ni 17} type structure of _Th 2 _{Zn 17} -type structure. 4. A single-peak particle size distribution having an average particle size of 10 to 10.
The rare earth magnet material according to any one of claims 1 to 3 , which is a powder of 300 µm. 5. An unavoidable impurity of 0.25% by weight.
The rare earth magnet material according to any one of claims 1 to 4 , which contains the following oxygen and 0.1% or less of carbon. 6. A rare earth bonded magnet, characterized in that the powder of the rare earth magnet material according to any one of claims 1 to 5 is bound with a resin. 7. The binder resin is a thermosetting resin, which has a density of 6.1 g / cm ³ after being subjected to a heat curing treatment after compression molding.
The rare earth bonded magnet according to claim 6 , which is an extra magnet. 8. The sheet-shaped molded article according to claim 6.
Rare earth bonded magnet.