JPH0617200A - Tetragonal rare earth element-iron-boron type compound - Google Patents

Abstract

PURPOSE:To provide a new compd. based on a tetragonal R-Fe-B compd., further contg. a substd. or modifying component and useful as a compd. forming a magnetic material and a permanent magnet material, etc. CONSTITUTION:This compd. is a tetragonal R(Fe, Co)B compd. contg. R (R is one or more kinds of rare earth elements including Y), Fe, Co and B as essential components and having a tetragonal system crystal structure with about 12Angstrom lattice constant c0 or a tetragonal R (Fe, Co)BA or RFeBA compd. (A is one or more among Ti, Ni, Bi, V, Nb, Ta, Cr, Mo, W, Mn, Al, Sb, Ge, Sn, Zr, Hf, Cu, S, C, Ca, Mg, Si, 0 and P). When these tetragonal compds. are isolated from each other by a nonmagneitc intermetallic compd. phase, the ideal fine structure of a permanent magnet is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rare earth / iron / boron-based tetragonal compound containing rare earth / iron / boron as an essential component. This tetragonal compound is the object of a substance invention useful as a constituent compound of a magnetic material or the like, particularly a permanent magnet.

R (rare earth element) and Co form various stable compounds. Among them, SmCo ₅ and Sm ₂ Co ₁₇ have high saturation magnetization, high Curie point, and large magnetic anisotropy constant, and an ultrahigh performance permanent magnet material was developed based on these compounds. Currently, RCo magnets are widely used in various applications such as small motors and small speakers.
However, these SmCo-based magnets are expensive because Sm, which is a scarce resource, contains a large amount of Co. Therefore, it is desired to develop a material containing little or no Sm or Co.

From the viewpoint of making a permanent magnet material for this purpose, an RFe compound having a huge anisotropy constant like an RCo compound has been noted. However, in the RFe system, there are not as many kinds of compounds as in the RCo system. Especially R
Among the elements, resource-rich light rare earths such as Ce, La, and Nd, R ₂ Fe ₁₇ type compounds and only a few other compounds (eg Nd ₆ Fe ₂₃ , PrFe ₂ ) have been found. . Since these compounds have a low Curie point and a small anisotropy constant, they do not exhibit the properties required for a practical permanent magnet.

Recently, it has been found that an ultra-quenched ribbon of an RFe alloy exhibits a high coercive force, and the interest as a permanent magnet material is increasing. However, the RFe ultra-quenching ribbon cannot provide a magnet having a practical shape and size, and cannot be said to be a practical permanent magnet. Also, in terms of magnetic properties, the ultra-quenched ribbon shows a lower value than the conventional magnet.

The basic object of the present invention is to provide a novel compound which contains R, Fe and the third component, which have not been achieved by the above-mentioned conventional techniques, as at least essential components and which is stable at room temperature or higher. The present invention provides a novel compound further containing a substitution or modification component based on a novel compound containing R, Fe and B as essential components, which is useful as a constituent compound of a magnetic material and a permanent magnet. Is the basic purpose. The present invention is also useful as a constituent compound of a magnetic material and a permanent magnet having or exhibiting excellent practical magnetic characteristics without necessarily using a large amount of Sm and Co which are conventionally required in practical use. Is intended to be provided.

That is, according to the disclosure of the application forming the basis of the present invention (Japanese Patent Application No. 58-94876), R (R is one or more rare earth elements including Y), Fe and B are essential components, and the lattice constant is An RFeB tetragonal compound having a tetragonal crystal structure with c ₀ of about 12Å is obtained. This RFeB tetragonal compound forms the basis of the present invention.

The present invention firstly relates to the above-mentioned RFeB type tetragonal compound in which Fe is replaced by Co, that is, R
Provide a (Fe, Co) B tetragonal compound (preferably not more than 50% Co by atomic ratio-% means atomic ratio unless otherwise specified). Substitution of Fe with Co has the effect of increasing the Curie point of a tetragonal compound.

Secondly, according to the present invention, such compounds are separated from each other by 1% or more by volume of the non-magnetic intermetallic compound phase, thereby providing a constituent compound capable of exhibiting excellent magnet characteristics. . In this case (particularly in the case of a sintered body), the average crystal grain size of the tetragonal compound is preferably 1 to 100 μm.

Further, in the present invention, the RFeB basic system,
Alternatively, an R (Fe, Co) B-based tetragonal compound containing the following specific A element also exhibits the same tetragonal system, and is useful and excellent as a constituent compound of a magnetic material and a permanent magnet. However, A element is Ti, Ni, Bi, V, Nb, T
a, Cr, Mo, W, Mn, Al, Sb, Ge, Sn,
It is one or more of Zr, Hf, Cu, S, C, Ca, Mg, Si, O and P.

That is, the third aspect of the present invention is that when R (where R is one or more rare earth elements including Y), Fe, B and the A element are essential components, the lattice constant c ₀ is about 12Å. An RFeBA tetragonal compound having a tetragonal crystal structure is provided.

In the present invention, fourthly, this RFeBA
The tetragonal compound is most excellent as a constituent compound of a permanent magnet when it is separated from each other by a nonmagnetic intermetallic compound phase of 1% or more by volume. In this case (particularly in the case of a sintered body), it is preferable that the RFeBA tetragonal compound has an average crystal grain size of 1 to 100 μm.

Fifth, the present invention provides an R (Fe, Co) BA tetragonal compound in the above RFeBA tetragonal compound, wherein Fe is partially replaced by Co (preferably 50% or less of Co). Further, sixthly, the isolation state is the same as in the fourth case.

In order to obtain useful magnetic properties, in the present invention, a compound having a tetragonal (see later) crystal structure must be the main phase in order to obtain a high-performance magnetic material or permanent magnet. . Here, the main phase means a phase that occupies 50% or more in volume ratio among some phases contained in the material. That is, as the main phase, one or more of R (Fe, Co) B compounds, RFeBA compounds, and R (Fe, Co) BA compounds are constituent compounds.

In the first to sixth inventions (embodiments) and 3
When manufacturing a magnetic material or a permanent magnet based on a tetragonal compound, the basic composition of R—Fe—B is B2 to 28%,
Excellent magnetic properties are obtained with R 8 to 30% and the balance substantially Fe, and preferably 40 to 90% of Fe is used as a basic system for Co substitution or A element addition.

When using a magnetic material or a permanent magnet, A
The amounts of the elements are preferably as follows: Ti 4.5% or less, Ni 8.0% or less, Bi 5.0% or less, V 9.5% or less, Nb 12.5% or less, Ta 10.5% or less, Cr 8.5% or less, Mo 9.5%. Below, W 9.5% or less, Mn 8.0% or less, Al 9.5% or less, Sb 2.5% or less, Ge 7.0% or less, Sn 3.5% or less, Zr 5.5% or less, Hf 5.5% or less, Cu 3.5% or less, S 2.0% Hereinafter, C 4.0% or less, Ca 8.0% or less, Mg 8.0% or less, Si 8.0% or less, O 1.0% or less, and P 3.5% (however, the A element may be contained in two or more, and in that case, the combination of the A element is The amount of the element A can be less than or equal to the maximum value of the contained A element).

The present invention will be described in detail below.

The present inventors have discussed the relationship between the magnetic properties and the structure of RFe compounds based on the results of conventional studies. As a result, the following things became clear.

(1) The magnetic properties of the RFe compound include
The interatomic distance between Fe atoms and the environment around Fe atoms (such as the number and type of nuclear atoms recently) play an extremely large role.

(2) There is no compound suitable for a permanent magnet in the crystalline state only by the combination of R and Fe.

The present inventors have found that in the RFe compound, F
It was judged that the presence of the third element is indispensable in order to change the environment around the e-atom and give the characteristics suitable as a permanent magnet. Therefore, the magnetic properties of the RFeX ternary compound containing various elements as the third element X were examined in detail. As a result, an RFeB basic compound containing B as X was found. It has been revealed that the RFeB basic compound is an unknown compound, has a higher Curie point and a larger anisotropy constant than the conventional RFe compound, and thus can be an excellent constituent compound of a permanent magnet material.

Further details will be described below with reference to examples.

Experimental method (1) Raw material (purity is% by weight) Fe: electrolytic iron 99.9% B: ferroboron or 99% pure BR: 99% Ti, Mo, Mn, Sb, Ni, Ta: 98% Al , Cu: 99.9% Hf: 95% V: Ferrovanadium (81.2% V) Nb: Ferroniobium (67.6% Nb) Cr: Ferrochrome (61.9% Cr) Zr: Ferrozirconium (75.5% Zr)

(2) The experimental procedure is as shown in FIG. The experimental results were as follows. The procedure (A) shows an experimental procedure for identifying a compound, and the procedure (B) shows an experimental procedure when a permanent magnet is used.

(1) A typical powder X-ray diffractometer pattern measured on a Fe-B-Nd basic sintered body (77Fe-15Nd-8B in atomic percentage ratio) showing high characteristics is shown in FIG. This pattern is extremely complex, and any RFe compound known so far, FeB
It cannot be explained by the compound or RB compound.

(2) According to the XMA measurement of the sample of (1), the sintered body is composed of three or four phases. The main phase contains Fe, B, and R at the same time, the second phase is an R-enriched phase in which R is 70% by weight or more, and the third phase is a phase richer in B than the main phase. The fourth phase is the oxide phase.

(3) As a result of analyzing the pattern of the powder X-ray diffractometer shown in FIG. 1, all the strong peaks contained in this pattern can be explained as tetragonal crystals with a ₀ = 8.80Å and c ₀ = 12.23Å. Figure 1 shows the index at each X-ray peak. It was found that the main phase simultaneously containing FeB and R observed in XMA measurement has this structure.
The feature of this structure is that the lattice constant is very large.
A tetragonal compound with such a huge lattice constant is
It is not known in any of binary compounds of RFe, FeB and BR.

(4) X-ray diffractometer measurement, XMA measurement, and optical microscope observation were performed on FeBR-based and FeCoBR-based permanent magnets having various compositions and prepared by various manufacturing methods including the above-mentioned method. As a result, the following became clear.

(I) In the presence of a tetragonal compound having a giant unit cell having R, Fe and B as basic components described in (3) and having lattice constants a ₀ about 9Å and c ₀ about 12Å, a permanent magnet is used. With good characteristics. Table 1 shows the lattice constants of the tetragonal compound of the main phase obtained for typical FeBR and FeCoBR magnets.

Good permanent magnet characteristics cannot be obtained with compounds based on conventional binary compounds such as RFe, FeB and BR.

(Ii) In the case where the tetragonal compound has an appropriate crystal grain size and the compound has a fine structure in which a nonmagnetic phase containing a large amount of R is mixed, the tetragonal compound has a structure of a permanent magnet. It exhibits particularly good properties as a compound.

In the permanent magnet based on the present tetragonal compound, the above-mentioned tetragonal compound has an average crystal grain size of 1 to 100 μm (preferably 1.5 to 90 μm, more preferably 1.5 to 80 μm).
m) is desirable, and when it is smaller than 1 μm or larger than 100 μm, Hc becomes 1 kOe or less, and the value of the material containing it as an industrial material decreases.

The ideal form of the tetragonal compound is that each fine particle having a high anisotropy constant is separated by a non-magnetic phase, and a high Hc is expressed in such a case. It turned out to be. The tetragonal compound of the present invention can form an ideal structure by forming the isolated fine particles, and a theoretical permanent magnet or a permanent magnet material can be designed based on this structure morphology. Therefore, the nonmagnetic phase must be 1% by volume or more. Since Hc is 1 kOe or more, the nonmagnetic phase needs to be at least 1% by volume, but it is not preferable to exceed 45%. The preferred range is 2 to 10%. The nonmagnetic phase is mainly composed of an intermetallic compound phase containing a large amount of R. As the non-magnetic phase, the oxide phase can partly work effectively.

(Iii) The above RFeB tetragonal compound can be produced in a wide composition range. Further, even if an element other than R, Fe and B is added or substituted, it can exist stably.

In order to exhibit good characteristics as a permanent magnet,
The composition range of the material is as follows. Atomic percentage of 2-28% B, 8-30% R and 40-90%
Alloy system (I) containing Fe as an essential component.

2 to 28% B, 8 to 30% R, 4
An alloy system (II) containing 0 to 90% Fe and 50% or less Co as essential components.

In the alloy systems (I) and (II), when B2% or less and R8% or less, Hc becomes 1 kOe or less, and the industrial value of a permanent magnet decreases. B28% or more,
When R is 30% or more, Br becomes 4 kG or less, which is lower than that of hard ferrite. In the alloy system (II), the Curie point of the tetragonal compound rises (300 to 750 ° C.) with an increase in the amount of Co substituted with Fe (300 to 750 ° C.), and the temperature characteristics are improved, but when Co is 50% or more, Hc is 1
The value becomes less than kOe, and the value of the permanent magnet becomes low. However, it may be used as a magnetic material other than the permanent magnet.

In addition to the above essential components, alloys containing various additive elements and impurity elements mixed in from raw materials and manufacturing processes can also have a tetragonal compound as the main phase within the above range, and in that case, a good permanent magnet can be obtained. Show the characteristics.

Further, H, Li, Na, K, B of 1% or less
e, Sr, Ba, Ag, Zn, N, F, Se, Te, P
Even if b is included, the basic tetragonal compound is stable and a good permanent magnet can be obtained.

As described above, the RFeB system or R (F
The (e, Co) B-type tetragonal compound is a compound that has not been known at all, and it is a novel fact that high characteristics as a permanent magnet can be obtained by using this compound as the main phase. The Curie point of an alloy based on the RFeB basic compound is R
It is in the range of about 300 to 370 ° C. based on the FeB basic compound, and an alloy based on such a compound has not been heretofore known.

Conventionally, there have been some reports on ribbon magnets in the RFe alloy by the ultra-quenching method, but the present invention is different from these known examples in the following points. That is, the ribbon magnet has the characteristics of a permanent magnet in the middle of the transition from the amorphous or stable crystalline state to the stable crystalline state. According to previous reports, these magnet materials have a high coercive force because the amorphous state remains or the metastable F
This is a state in which e ₃ B and R ₆ Fe ₂₃ exist as the main phase. In the magnet based on the tetragonal compound of the present invention, no residual alloy phase in the amorphous state is detected, and the Fe ₃ B or R ₆ Fe ₂₃ phase is not the main phase.

In the tetragonal compound of the present invention, the rare earth element R is a rare earth element including Y and including light rare earth and heavy rare earth, and at least one of them is used. That is, this R
As Nd, Pr, La, Ce, Tb, Dy, H
o, Er, Eu, Sm, Gd, Pm, Tm, Yb, Lu
And Y are included. A light rare earth element is sufficient as R, and Nd and Pr are particularly preferable. Usually, one of R is sufficient, but in practice, a mixture of two or more kinds (Misch metal, didymium, etc.) can be used for reasons such as convenience of availability, and Sm, Y, Er, Tm, Ce, Gd, etc. Is another R (Nd, Pr, Tb, D) mainly composed of Nd and Pr.
y, Ho) can be used as a mixture. La
Must be used as a mixture with other R mainly composed of Nd and Pr. It should be noted that R does not have to be a pure rare earth element, and may contain impurities that are unavoidable in production within a range that is industrially available.

As B (boron), pure boron or ferroboron can be used, and Al and S as impurities.
Those containing i, C, etc. can also be used.

The tetragonal compound of the present invention and the permanent magnet or the permanent magnet material containing the tetragonal compound will be described in more detail with reference to examples.

Example 1 (Reference Example) An alloy of 6 at% B, 16 at% Pr and the balance Fe was pulverized to prepare a powder having an average particle size of 15 μm. 2 t of this powder
It was pressed in a magnetic field of 19 kOe at a pressure of / cm ² and sintered in Ar at 2 × 10 ⁻¹ Torr at 1090 ° C. for 1 hour.

According to X-ray diffraction, the main phase of this sintered body was a tetragonal compound, and the lattice constants were a ₀ = 8.85Å, c ₀ = 12.
It was 26Å. As a result of XMA and optical microscope observation, the main phase simultaneously contained Fe, B, and Pr, and occupied 90% by volume. The total volume of the non-magnetic compound phase containing 80% or more of R forming the grain boundary phase of the main phase was 3% by volume, and the rest was oxides and pores. The average crystal grain size of this tetragonal compound was 25 μm.

The results of the magnetic measurement are as follows. Br
= 9.9kG, Hc = 6.5kOe, (BH) max = 18M
GOe This is a much higher value than conventional ribbon magnet materials.

Example 2 (Reference Example) 8 at% B, 15% at Nd and the balance Fe alloy were pulverized to prepare a powder having an average particle size of 3 μm. 2 t / c of this powder
Pressed in a magnetic field of 10 kOe at a pressure of m ² for 2 ×
Sintered in Ar at 10 ^-1 Torr for 1 hour at 1100 ° C.

According to X-ray diffraction, the main phase of this sintered body was a tetragonal compound, and the lattice constants were a ₀ = 8.80Å, c ₀ = 12.2.
It was 3Å. As a result of observation by XMA and an optical microscope, the main phase contained 90.5% by volume of Fe, B, and Nd at the same time. The nonmagnetic compound phase containing 80% or more of R constituting the grain boundary phase of the main phase had a volume ratio of 4%, and the rest was mostly oxides and pores. The average crystal grain size of this tetragonal compound is 15
was μm.

The magnetic characteristics are Br = 12.1kG and Hc = 9.3k.
Oe, (BH) max = 34MGOe. This is a much higher value than the conventional ribbon magnet.

Example 3 10 at% Co, 8 at% B, 15 at% Nd, balance F
The alloy of e was pulverized to prepare a powder having an average particle size of 1.1 μm. This powder was pressed in a magnetic field of 12 kOe at a pressure of ² t / cm ² and then heated in Ar at 1.5 Torr at 1080 ° C.
Sintered for 1 hour.

According to X-ray diffraction, the main phase of this sintered body was a tetragonal compound, and the lattice constants were a ₀ = 8.79Å and c ₀ = 12.2.
It was 1Å. As a result of XMA and optical microscope observation, the main phase contains Fe, Co, B, and Nd at the same time, and the volume ratio is 90%.
Was occupied.

The nonmagnetic compound phase containing 80% or more of R was 4.5% in volume ratio, the rest was mostly oxides and pores, and the average crystal grain size of the tetragonal compound was 3.1 μm.

The results of the magnetic measurement are as follows. Br = 12.0 kG, iHc = 9.2 kOe, (BH) max
= 34 MGOe This is a much higher value than the conventional ribbon magnet material.

Example 4 (Reference Example) 5 at% B, 7 at% Nd, 3 at% Pr, 2 at% T
b, an alloy of the balance Fe was pulverized to prepare a powder having an average particle size of 2.1 μm. This powder was added at a pressure of ² t / cm ² to 15 kO
Pressed in the magnetic field of e, 11 in 1 Torr of Ar
Sintered at 30 ° C. for 1 hour.

According to X-ray diffraction, the main phase of this sintered body was a tetragonal compound, and the lattice constants were a ₀ = 8.80Å and c ₀ = 12.2.
It was 4Å. As a result of XMA and optical microscope observation, the main phase contained Fe, Nd, Pr, Tb, and B, and the volume ratio was 91%.
Was occupied. The volume ratio of the non-magnetic compound phase containing 80% or more of R is 1.5%, the content of Fe-rich ferromagnetic low coercive force phase is 1% by volume, and the balance is mostly oxides and pores. The average crystal grain size of the compound was 5 μm.

The results of the magnetic measurement are as follows. Br = 11.5kG, iHc = 4kOe, (BH) max
= 17 MGOe This is a much higher value than the conventional ribbon magnet.

Example 5 (reference example) 17 at% B, 10 at% Nd, 3 at% La, 2 at
%, Gd balance Fe alloy was pulverized to prepare a powder having an average particle diameter of 2.7 μm. This powder was applied at a pressure of 4 t / cm ² to 12
It was pressed in a magnetic field of kOe and sintered in Ar at 1.5 Torr at 1080 ° C. for 1 hour.

According to X-ray diffraction, the main phase of this sintered body was a tetragonal compound, and the lattice constants were a ₀ = 8.82Å and c ₀ = 12.2.
It was 2Å. As a result of XMA and optical microscope observation, the main phase contained Fe, B, Nd, La, and Gd, and occupied 82% by volume. The volume ratio of the non-magnetic compound phase containing 80% or more of R was 12%, the rest was almost pores, and the average crystal grain size of the tetragonal compound was 7 μm.

The results of magnetic measurement are as follows. Br = 8.2 kG, iHc = 5.0 kOe, (BH) max =
15MGOe This is a much higher value than the conventional ribbon magnet material.

Example 6 (Reference Example) An alloy of 17 at% B, 28 at% Nd and the balance Fe was pulverized to prepare a powder having an average particle diameter of 5 μm. 2 t of this powder
It was pressed in a magnetic field of 12 kOe at a pressure of / cm ² and sintered at 2 × 10 ⁻¹ Torr 1050 ° C. for 1 hour. After sintering, it was cooled with an Ar stream. According to X-ray diffraction, the peak of the tetragonal compound is lower than the peaks of the other phases in this sintered body, and this compound is not the main phase. As a result of XMA and optical microscope observation, the tetragonal compound is 48% by volume.
The non-magnetic compound phase containing 80% or more of R was 47%. The rest was almost pores, and the average crystal grain size was 16 μm of the tetragonal compound.

The results of magnetic measurement are as follows. Br = 4.2kG, iHc = 13.2kOe, (BH) max
= 3.7MGOe This is lower than the characteristics of ferrite magnets.

When controlled cooling was performed at 5 ° C./min after sintering, the magnetic characteristics were increased as follows. Br = 4.5 kG, iHc = 13.3 kOe, (BH) max
= 4.2 MGOe

According to X-ray diffraction of the slowly cooled sample, the peak of the tetragonal compound became stronger. According to XMA measurement and optical microscope observation, the tetragonal compound had a volume ratio of 53%, and the nonmagnetic compound phase containing 80% or more of R had a volume ratio of 43%. The remainder was mostly pores, and the average crystal grain size of the tetragonal compound was 17 μm.

Example 7 (Reference Example) Alloys having the compositions shown in Table 1 were subjected to high frequency melting, a material was prepared by the process of FIG. 2A, and the structure of the main phase was determined by X-ray diffraction. The results are shown in Table 1. This shows that the tetragonal compound is stable from room temperature to the sintering temperature in a wide composition range of Fe-B-Nd system.

These RFeB tetragonal compounds are conventional R
It is a constituent compound of a magnetic material having unique characteristics that cannot be realized by any combination of Fe, FeB, and RB, and is extremely valuable as an industrial material.

In most of the RFeB compounds, the angle formed by each of the a-axis, b-axis, and c-axis directions is 90 ° within the measurement error range, and a ₀ = b ₀ ≠ c ₀ . It can also be slightly off (eg within about 1 °). It also includes the case where a ₀ and b ₀ are slightly different.
However, also in this case, it is called a tetragonal crystal in a substantial sense.

[0067]

[Table 1]

FIG. 3 is a typical example of a permanent magnet body (1) Fe-10Co-9B-14Nd-2M which has various FeCoBRA compounds prepared by the following steps as constituent compounds.
o and (2) Fe-20Co-8B-15Pr-2Zr
Regarding the magnetic properties with the average crystal grain size D of the tetragonal compound. 4 to 6 show the relationship between the magnetic characteristics and the M content when various A elements (M) are used.

(1) The alloy was melted by high frequency and cast in a water-cooled copper mold, the starting materials were electrolytic iron having a purity of 99.9% as Fe, and ferroboron alloy as B (19.38% B, 5.32% Al, 0.74).
% Si, 0.03% C, balance Fe), and a purity of 99.7% or more as R (impurities are mainly other rare earth metals).

As Co, electrolytic Co having a purity of 99.9% was used.

As the A element (M), Ti and M having a purity of 99%
As o, Bi, Mn, Sb, Ni, Ta, Ge, 98% W, 99.9% Al, Sn, 95% Hf, and V
Ferrobadium containing 81.2% V, 67.6% as Nb
Of Nb-containing ferroniobium, Cr of 61.9% Cr of ferrochrome and Zr of 75.5% of Zr of ferrozirconium were used.

(2) Pulverization Coarse pulverization was performed by a stamp mill to a size of 35 mesh through, and then 3 by a ball mill.
Finely pulverized for 3 hours (3 to 10 μm).

(3) Orientation and molding in a magnetic field (10 kOe) (pressurized at 1.5 t / cm ² ).

(4) Sintering: 1000 to 1200 ° C., 1 hour in Ar, after sintering, let cool.

Next, in the above-mentioned method, (2) crushing is performed with Fish.
er sub-sieve sizer (sub-sieve)
-Sizer) has an average particle size measured value of 0.5 to 100 μm
Samples of various compositions were prepared by appropriately changing the crushing time so as to take each value of.

Comparative Example: In order to obtain a crystal grain size of 100 μm or more, after the sintering, the temperature A was 5 to 20 ° C. lower than the sintering temperature.
It was kept in the atmosphere for a long time.

Magnetization was examined for the samples of the respective compositions thus obtained, and the magnet characteristics and the average crystal grain size of the tetragonal compound were measured. The result is shown in FIG. Here, the average crystal grain size means a straight line that divides the circle into eight equal parts by drawing a circle of a known area by taking a photomicrograph of × 100 to × 1000 using an optical microscope after polishing and corroding the sample surface. It was drawn and the average number of particles on the diameter was counted and calculated. However,
The number of particles separated on the boundary (on the circumference) is counted as 1/2 (this method is known as the Heyn method). Omit the voids from the calculation.

The sample of composition (1) has an average crystal grain size D of 9.2 μm.
The energy product (BH) max28.5MGOe is shown at m, and the sample of the composition (2) has (BH) m at D 4.6 μm.
It showed ax25.4 MGOe.

[0079]

EFFECTS OF THE INVENTION The present invention is based on a novel RFeB basic tetragonal compound that exists stably from room temperature to the sintering temperature, and R (Fe, Co) B type, and the specific element A
A novel tetragonal compound of RFeBA type and R (Fe, Co) BA type containing is provided. Specifically, not only does the substitution of Co significantly increase the Curie temperature of the FeBR basic tetragonal compound, and the inclusion of the specific element A not only allows it to exist stably without losing its basic magnetic properties, It has the excellent utility that various modifications or improvements can be made depending on desired properties. The increase in the Curie temperature of the tetragonal compound guarantees the specific possibility of developing a permanent magnet that does not lose its high performance even at high temperatures, as a compound of a constituent element of the permanent magnet.

Further, the tetragonal compounds separated from each other by the predetermined non-magnetic intermetallic compound phase are epoch-making because they reveal the ideal microstructure as a permanent magnet. Such an isolation structure establishes the technical basis for the design of an ideal permanent magnet.

Thus, in the present invention, these tetragonal compounds and their isolated structures have significance as inventions of the material, and are different in dimension from the sintered permanent magnet material that was the clue to reach this finding. It is a basic technical idea to provide further improvement of sintered permanent magnets and guidelines for development of high-performance magnets close to theoretical values, and further design and development of various magnets based on these tetragonal compounds. Scientific,
It gives practical guidance. That is, not to mention its scientific significance in the field of permanent magnets, it is a breakthrough that marks a major epoch in the development of various magnetic material-related technologies and industries beyond permanent magnets.

[Brief description of drawings]

FIG. 1 is a photograph showing a measurement result pattern of a representative Fe—B—Nd sintered body sample, which is a reference example of the present invention, by a powder X-ray diffractometer.

FIG. 2 is a flowchart showing the procedure of an experiment.
((A) shows compound identification, (B) shows permanent magnet)

FIG. 3 is a graph showing the relationship between the average crystal grain size D (μm) and the coercive force iHc.

FIG. 4 is a graph showing the relationship between the A element (M) content of a FeCoBRA permanent magnet and iHc.

FIG. 5 is a graph showing the relationship between the A element (M) content of the FeCoBRA permanent magnet and iHc.

FIG. 6 is a graph showing the relationship between the A element (M) content of the FeCoBRA permanent magnet and iHc.

[Procedure amendment]

[Submission date] June 8, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

FIG. 1 is a diagram showing a measurement result pattern of a powder X-ray diffractometer of a representative Fe—B—Nd sintered body sample as a reference example of the present invention.

Claims (6)

[Claims] 1. R (where R is one or more rare earth elements including Y), Fe, Co and B are essential components, and the lattice constant c _{0 is}
Has a tetragonal crystal structure of about 12Å
o) B tetragonal compound. 2. R (where R is one or more rare earth elements including Y), Fe, Co and B are essential components, and the lattice constant c _{0 is}
Is a compound having a tetragonal crystal structure of about 12Å and is isolated from each other by 1% by volume or more of the whole non-magnetic intermetallic compound phase.
o) B tetragonal compound. 3. R (where R is one or more rare earth elements including Y), Fe, B and A elements (where A element is one or more of the following A elements) are essential components and have a lattice constant c. ₀ is about 1
RFeBA tetragonal compound having a 2Å tetragonal crystal structure (A element: Ti, Ni, Bi, V, Nb, Ta, C
r, Mo, W, Mn, Al, Sb, Ge, Sn, Zr,
Hf, Cu, S, C, Ca, Mg, Si, O, and P). 4. R (where R is one or more rare earth elements including Y), Fe, B and A elements (where A element is one or more of the following A elements) are essential components and have a lattice constant c. ₀ is about 1
An RFeBA tetragonal compound (A element: Ti), which is a compound having a 2Å tetragonal crystal structure and is isolated from each other by a nonmagnetic intermetallic compound phase of 1% or more of the whole by volume ratio. , Ni, Bi, V, Nb, T
a, Cr, Mo, W, Mn, Al, Sb, Ge, Sn,
Zr, Hf, Cu, S, C, Ca, Mg, Si, O, and P). 5. A lattice constant, wherein R (where R is one or more rare earth elements including Y), Fe, Co, B and A elements (where A element is one or more of the following A elements) are essential components, and C ₀
With a tetragonal crystal structure in which R is about 12Å
e, Co) BA tetragonal compound (A element: Ti, Ni, B)
i, V, Nb, Ta, Cr, Mo, W, Mn, Al, S
b, Ge, Sn, Zr, Hf, Cu, S, C, Ca, M
g, Si, O, and P). 6. A lattice constant comprising R (provided that R is one or more rare earth elements including Y), Fe, Co, B and A elements (provided that A is at least one of the following A elements) as essential components. C ₀
With a tetragonal crystal structure in which R is about 12Å
e, Co) BA tetragonal compound, characterized in that the tetragonal compound is separated from each other by 1% by volume or more of the whole non-magnetic intermetallic compound phase.
o) BRA tetragonal compound (A element: Ti, Ni, Bi,
V, Nb, Ta, Cr, Mo, W, Mn, Al, Sb,
Ge, Sn, Zr, Hf, Cu, S, C, Ca, Mg,
Si, O, and P).