JPH089752B2 - Method for manufacturing R1R2FeCoB-based permanent magnet - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a high-performance rare earth / iron-based permanent magnet which does not use a large amount of expensive and scarce resource cobalt .
It relates to a manufacturing method .

[0002]

2. Description of the Related Art Permanent magnet materials are extremely important electric materials used in a wide range of fields from various household electric appliances to automobiles, communication parts, and peripheral terminals of large computers.
It is one of electronic materials. Along with the recent demand for higher performance and smaller size of electric and electronic devices, higher performance of permanent magnet materials is also required.

Alnico is a typical current permanent magnet material.
Hard ferrite and rare earth cobalt magnets. With the recent destabilization of the raw material situation for cobalt, the demand for alnico magnets containing 20 to 30 wt% cobalt has decreased, and cheap hard ferrite containing iron oxide as the main component has become the mainstream of magnet materials. became. On the other hand, the rare earth cobalt magnet is a high-performance magnet having a maximum energy product of 20 MGOe or more, but it contains 50 to 65% by weight of cobalt and is very expensive because it uses a large amount of Sm which is rarely contained in rare earth ores. is there. However, since it has much higher magnetic characteristics than other magnets, it has come to be used mainly in small-sized and high-value-added magnetic circuits.

In order for a high-performance magnet such as a rare earth cobalt magnet to be used in a wider field at a low cost and in a large amount, it does not contain expensive cobalt and is contained as a rare earth metal in a large amount in an ore. It is necessary to use light rare earth elements such as neodymium and praseodymium as the main components.

Attempts to replace such rare earth cobalt magnets with permanent magnet materials were first made with rare earth / iron binary compounds.

Compared to rare earth cobalt-based compounds, rare earth / iron-based compounds have fewer kinds of compounds and generally have a lower Curie point. Therefore, in the casting method and powder metallurgical method used for magnetizing the rare earth cobalt compound, no method has hitherto been successful for the rare earth iron-based compound.

AE Clark found that sputtered amorphous TbFe ₂ has a high coercive force (Hc) of 30 kOe at 42 ° K, and by heat treating at 300-350 ° C., Hc = 3.4 kOe at room temperature, Maximum energy product ((BH) ma
We found that x) = 7MGOe (Appl. Phys. Let
t. 23 (11), 1973, 642-645).

[0008] JJ Croat et al. Are ultra-quenched ribbons of NdFe and PrFe using light rare earth elements of Nd and Pr, and Hc =
It is reported to exhibit 7.5 kOe. However, Br is 5kG
Below, (BH) max only shows 3-4 MGOe (Appl. P
hys. Lett. 37, 1980, 1096, J. Appl. Phys. 53, (3)
1982, 2402-2406).

As described above, two methods, that is, a method of heat-treating an amorphous material prepared in advance and a super-quenching method have been known as the most promising means for obtaining a rare earth / iron-based magnet.

However, the materials obtained by these methods are thin films or ribbons, and are not magnetic materials used in general magnetic circuits such as speakers and motors. further,
NC Koon et al. Obtained a super-quenched ribbon of FeB alloy containing heavy rare earth elements by adding La,
It was found that Hc = 9 kOe was reached by heat treating a ribbon having a composition of (Fe _0.82 B _0.18 ) _0.9 Tb _0.05 La _0.05 (Br = 5 kG, Appl. Phys. Lett. 39 (10), 1981, 840- 84
2).

[0011] L. Kabacoff et al. Noted that the FeB alloy facilitates amorphization, and (Fe _0.8 B
_0.2 ) _1-x Pr _x (X = 0 to 0.3 atomic ratio) composition of ultra-quenched ribbon was prepared, but Hc at room temperature was obtained only at the level of several Oe (J. Appl. Phys. 53 (3) 1982, 2255 ~
2257).

The magnets obtained from these amorphous thin films formed by sputtering and the ultra-quenched ribbons are thin and subject to dimensional restrictions, and are not practical permanent magnets that can be used as they are in general magnetic circuits. That is, it is impossible to obtain a bulk permanent magnet body having an arbitrary shape and size such as a conventional ferrite or rare earth cobalt magnet. Further, both the sputtered thin film and the ultra-quenched ribbon are essentially isotropic and have low magnetic properties at room temperature, and it is practically impossible to obtain a high-performance magnetic anisotropic permanent magnet from them.

Recently, permanent magnets are becoming more and more harsh environments-for example, strong demagnetizing field due to thinning of magnets, strong reverse magnetic field applied by coils and other magnets, and high speed and high load of equipment. Therefore, in many applications, higher coercive force is required for stabilizing the characteristics. (In general, the iHc of a permanent magnet decreases as the temperature rises. Therefore, if iHc at room temperature is small, demagnetization occurs when the permanent magnet is exposed to high temperatures.
Is sufficiently high, such demagnetization does not substantially occur. )

Ferrite and rare earth cobalt magnets use additive elements and different composition systems in order to achieve a high coercive force, but in that case, the saturation magnetization generally decreases, and (BH) max
Is also low.

[0015]

SUMMARY OF THE INVENTION The basic object of the present invention is to provide a novel method for producing a practical permanent magnet that solves the above-mentioned problems.

From this point of view, the present inventors first found that R-Fe
Aiming to make a compound magnet with a high Curie point and stable around room temperature based on a binary system, as a result of exploring many systems, FeBR and FeBRM compounds are particularly suitable for magnetization I found that (Japanese Patent Application No. 57-14507)
2, Japanese Patent Application No. Sho 57-200204).

Here, R represents at least one or more of rare earth elements including Y, and light rare earth elements such as Nd and Pr are particularly desirable. B represents boron. M is Ti, Zr, Hf,
Cr, Mn, Ni, Ta, Ge, Sn, Sb, Bi, Mo, Nb, Al, V, W
Indicates one or more selected from.

This FeBR magnet has a Curie point of 300 ° C. or higher, which is practically sufficient, and can be obtained by the same powder metallurgical method as ferrite and rare earth cobalt, which have not been successful in the R-Fe binary system. .

Further, as R, the main composition is a light rare earth element such as Nd and Pr, which is rich in resources, does not necessarily contain expensive Co and Sm, and has the best characteristics ((BH) m of the conventional rare earth cobalt magnet.
It has characteristics of (BH) max 36MGOe or more, which greatly exceeds ax = 31MGOe).

Further, the present inventors have found that these FeBR series, FeBR
It was found that the M-based compound alloy has a crystallographic X-ray diffraction pattern that is completely different from that of conventional amorphous thin films and ultra-quenched ribbons, and has a tetragonal crystal structure with novel magnetic anisotropy as the main phase ( Japanese patent application 58-94876). The Curie points of these FeBR-based and FeBRM-based compound magnets are generally around 300 ° C to 370 ° C. Furthermore, in these systems, the permanent magnets containing 50 atomic% or less of Co by substituting Fe have higher Curie. It has the following points and is filed by the same applicant (FeCoBR-based Japanese Patent Application No. 57-166663 and FeCoBRM-based Japanese Patent Application No. 58-5813).

The present invention further includes the aforementioned FeCoBR and FeCoBR.
The magnetic anisotropy permanent used for permanent magnets that has a high Curie point obtained in M-based compound magnets and a high maximum energy product (BH) max that is almost equal to or higher than these and has improved temperature characteristics, especially iHc. The specific purpose is to realize a magnet alloy material.

[0022]

According to the present invention SUMMARY OF], FeCoBR around the light rare earth such as Nd or Pr as R and FeCoBR
R based on heavy rare earths as part of R in M-based compounds
₁ contains _one of Dy, Tb, Gd, Ho, Er, Tm, Yb
And, by further performing a predetermined heat treatment, RFeCoB
IHc was further improved while maintaining a high (BH) max in the system and RFeCoBM magnets.

That is, the method of manufacturing the permanent magnet according to the present invention is as follows.

When the sum of the following rare earth elements R ₁ and light rare earth elements R ₂ is R, R ₁ 0.05 to 5% in terms of atomic percentage, R 12.5
.About.20%, B 4 to 20%, the balance consisting essentially of Fe, said F
Co of 35% or less (excluding 0%) of a part of e with respect to the total composition
In was replaced, the permanent magnet alloy containing, as a main phase tetragonal crystals having anisotropy: (wherein, R ₁ is Dy, Tb, Gd, H
One or more of O, Er, Tm and Yb, R ₂ is one or more of Nd and Pr, or the total of Nd and Pr is 80% or more and the rest is Y other than R _1.
At least one of the rare earth elements including ) 900 ~ 1200
Sintered at ℃, heat-treated at 350 ℃ or more and below the sintering temperature
R ₁ R ₂ FeCoB type permanent magnet characterized by increasing coercive force
Manufacturing method of permanent magnet .

When the sum of R ₁ and R ₂ below is R, R ₁ 0.05 to 5%, R 12.5 to 20%, B 4 to 20% in terms of atomic percentage,
One or more of the following additional elements M of a predetermined% or less (however, when M includes two or more of the above additional elements, the total amount of M is less than the atomic percentage of the one having the maximum value among the additional elements), and the balance. Substantially consisting of Fe, and a part of the Fe is replaced with Co of 35% or less (excluding 0%) with respect to the total composition,
Permanent magnet alloy containing a tetragonal crystal having magnetic anisotropy as a main phase: ( where R ₁ is Dy, Tb, Gd, Ho, Er, Tm, Yb
One or more of, R ₂ is Nd and Pr one or more, or remain in Nd and Pr total 80 percent or more is at least one rare earth element including Y other than R _1, additional element M is the following As: Ti 3%, Zr 3.3%, Hf 3.3%, Cr 4.5%, Mn 5%, Ni 6%, Ta 7%, Ge 3.5%, Sn 1.5%, Sb 1%, Bi 5%, Mo 5.2%, Nb 9%, Al 5%, V 5.5%, W 5% ) is sintered at 900 to 1200 ° C, and at 350 ° C or higher and the sintering temperature or lower.
R ₁ R ₂ characterized by heat treatment to increase coercive force
Manufacturing method of FeCoB type permanent magnet .

Further, the final product may contain typical impurities having the following numerical values or less. Cu 2%, C 2%, P 2%, Ca 4%, Mg 4%, O 2%, Si 5%, S 2%. However, the total amount of impurities is 5% or less.

It is expected that these impurities will be mixed in the raw material or the manufacturing process, but if the amount exceeds the above-mentioned limit amount, the characteristics deteriorate. Of these, Si raises the Curie point,
It also has the effect of improving corrosion resistance, but if it exceeds 5%, iHc decreases. Although Ca and Mg may be contained in the R raw material in a large amount and also have an effect of increasing iHc, it is not desirable to contain Ca and Mg in a large amount because they lower the corrosion resistance of the product.

In the present invention, boron (B) is added as in conventional magnetic materials, for example, as an amorphization promoting element in the production of an amorphous alloy or a sintering promoting element in powder metallurgy. R-Fe (C
o) -B is an essential constituent element of the tetragonal compound.

According to the method for producing a permanent magnet having the above composition,
While having a high maximum energy product , increase dramatically
High-performance magnet can be obtained with the coercive force.

[0030]

The function of the present invention will be described in detail below.

Although the magnet using the FeBR compound has a high (BH) max as described above, iHc is about the same level (5 to 10 kOe) as the Sm ₂ Co ₁₇ type magnet, which is a typical conventional high performance magnet. It was

This indicates that the magnetic field is easily demagnetized by receiving a strong demagnetizing field or the temperature rises, that is, the stability is not good. The iHc of a magnet generally decreases with increasing temperature. For example, the 30MGOe-class Sm ₂ Co ₁₇ type magnets and FeBR magnets mentioned above hold a value of only about 5 kOe at 100 ° C. (Table 4)

Since magnetic disk actuators for computers and motors for automobiles have strong demagnetizing fields and temperature rises,
It cannot be used with such iHc. In order to obtain further stability even at high temperature, it is necessary to have a high Curie point and increase the iHc value near room temperature.

It is also well known that, even near room temperature, a higher iHc is generally more stable against deterioration (aging) of the magnet over time and physical disturbance such as impact or contact. ing.

From the above, as a result of further detailed study centered on the FeCoBR component system, the present inventors have found that one or more of Dy, Tb, Gd, Ho, Er, Tm, and Yb in the rare earth elements, Nd or Pr
By combining light rare earth elements such as
It was possible to obtain a high coercive force that could not be obtained with the FeCoBR and FeCoBR magnets. By applying a predetermined heat treatment ,
The effect of increasing the coercive force of the R ₁ element becomes more remarkable.

Furthermore, in the component system according to the present invention, not only the increase in iHc, improvement of squareness of the demagnetization curve, i.e. (BH) max
It was found that it also had the effect of further increasing.

The inventors of the present invention used the iH of the FeCoBR compound magnet.
As a result of various studies to increase c, we have already found that the following method is effective. That is, (1) increase the content of R or B. (2) Add the additive element M. (FeCoBRM compound)

However, each of the methods of increasing the R or B content increases iHc, but as the content increases, Br decreases, and as a result, the value of (BH) max also decreases.

The additional element M also has an effect of increasing iHc, but (BH) max decreases as the amount of addition increases, and it does not lead to a dramatic improvement effect.

In the permanent magnet using the alloy of the present invention,
Based on the content of the rare earth element R centered on heavy rare earth, the main constituent of R ₂ is Nd and Pr, and the composition within the predetermined range of R, B, and Co, iHc when subjected to aging treatment
Is significantly increased. That is, when aging treatment is performed on a sintered body made of an alloy having the above specific composition, iHc is increased without deteriorating the value of Br, and there is also an effect of improving the squareness of the demagnetization curve, and (BH) max is Almost equal or better,
The effect is remarkable. In addition, the range of R, B, Co,
By specifying the amount of (Nd + Pr), iHc of about 10 kOe or more is achieved even before aging treatment, and R ₁ in R ₁
The effect of aging treatment is further remarkably added by the predetermined content of.

[0041] That is, according to this onset bright, high (BH) while the ma x had coercive <br/>, dramatically increase the Tc of about 310 to about 640 ° C. and iHc
Provided is a high-performance magnet which has a large degree of stability and can be applied to a wider range of applications than conventional high-performance magnets.

The maximum values of (BH) max and iHc are 40.6 MGOe, respectively.
(Table 2, No. 17) and 20.0 kOe (Table 2, No. 19) are shown.
R used in the permanent magnet of the present invention is composed of the sum of R ₁ and R ₂ , but includes Y as R, and Nd, Pr, La, Ce, Tb, Dy, H
It is a rare earth element such as o, Er, Eu, Sm, Gd, Pm, Tm, Yb, and Lu. Of these, R ₁ is at least one of the seven types of Dy, Tb, Gd, Ho, Er, Tm, and Yb, and R ₂ is a rare earth element other than the above seven types, and in particular, the sum of Nd and Pr of light rare earths. 80%
What includes the above is used. (However, Sm is expensive and iH
Since it lowers c, it is preferable that it be as small as possible.
Is often contained as an impurity in the rare earth metal, but it is still preferable that it is small. )

These R may not be pure rare earth elements,
It does not matter as long as it contains impurities (other rare earth elements, Ca, Mg, Fe, Ti, C, O, etc.) that are unavoidable in manufacturing within the industrially available range.

As B (boron), pure boron or ferroboron can be used, and those containing Si, C or the like as impurities can also be used.

The permanent magnet using the alloy of the present invention has the above-mentioned R content.
Is the sum of R ₁ and R ₂ in atomic percentage of R ₁ 0.05 to 5%,
R 12.5 to 20%, B 4 to 20%, Co 35% or less, balance Fe composition of coercive force iHc about 10 kOe or more, residual magnetic flux density Br
High coercive force and high energy product of 9 kG or more and maximum energy product (BH) max 20 MGOe or more (in the case of anisotropy, the same applies below.
The same) .

0.2 to 3% of R ₁ , R 13 to 19%, B 5 to 1
1%, Co 23% or less, balance Fe composition is the maximum energy product
(BH) max is 29 MGOe or more, which is a preferable range.

Dy and Tb are particularly desirable as R ₁ .

The amount of R is set to 12.5% or more because if R is less than this amount, Fe is precipitated in the alloy compound of the present system and the coercive force is drastically reduced. The upper limit of R is set to 20%. Even if it is 20% or more, the coercive force shows a large value of 10 kOe or more, but Br decreases and Br (max) exceeds 20MGOe.
Is not obtained.

The amount of R ₁ is captured by substituting for R above. The amount of R ₁ is only 0.2 as shown in Table 2, No.2.
It can be seen that even with the substitution of%, Hc is increased, the squareness of the demagnetization curve is also improved, and (BH) max is increased. R ₁
The lower limit of the amount is set to 0.05% or more in consideration of the effect of increasing iHc and the effect of increasing (BH) max (see Fig. 2). IHc increases as the amount of R ₁ increases (Table 2, No. 2
7), (BH) max decreases gradually with a peak at 0.4%, but (BH) max shows 29 MGOe or more even with 3% substitution (see FIG. 2).

For applications in which stability is particularly required, it is advantageous that the iHc is high, that is, the content of R ₁ is large, but the elements constituting R ₁ are contained in the rare earth ore in a small amount. No, it is very expensive. Therefore, the upper limit is 5%. When the amount of B is 4% or less, iHc is 10 kO
e is less than or equal to Also, the increase of B amount is the same as the increase of R amount iH
Increase c, but decrease Br. (BH) max 20MGOe
In order to be above, B20% or less is necessary.

[0051] In the manufacturing method of the permanent magnet of the present invention, when the content of 35% or less of Co is (BH) Temperature characteristics while maintaining a high max but is improved, generally adding Co to Fe alloy, its It is difficult to predict the effect of addition because the Curie point increases in some cases and decreases in comparison with the addition amount.

The Curie point when a part of Fe in the FeBR system in the permanent magnet ( alloy ) of the present invention is replaced with Co is shown in FIG.
As shown in (3), it gradually increases as the substitution amount of Co increases. Co
Even a small amount (for example, 0.1 to 1%) is effective for increasing the Curie point, and as shown in FIG.
Alloys and magnets with arbitrary Curie points from 10 to about 640 ° C can be obtained. When Fe is replaced by Co, iHc
Shows a decreasing tendency, but initially (BH) max increases slightly because the squareness of the demagnetization curve is improved.

When Co is 25% or less, Co has other magnetic properties, especially (B
It contributes to the increase of the Curie point without substantially affecting H) max, and is equal to or higher than Co23% in particular. When the Co content exceeds 25%, (BH) max decreases, and when it exceeds 35%, it further decreases, and (BH) max becomes lower than 20MGOe. In addition, the temperature coefficient of Br (room temperature to 140
The average value of ° C is about 0.1% / ° C or less. FeCo of the present invention
BR-based magnets also showed a very small demagnetization factor in the exposure test at 100 ° C after room temperature magnetization at 100 ° C compared to Sm ₂ Co ₁₇ magnets or FeBR magnets containing no R ₁ component, and the stability was greatly improved. ing.

Similar discussions regarding Co also hold for the FeCoBRM system, and the effect of increasing the Curie point varies somewhat depending on the element added to M, but the basic tendency is the same.

The additive element M has the effect of increasing iHc and increasing the squareness of the demagnetization curve. On the other hand, as the amount of addition increases,
Since Br decreases, Br 9 kG or more is required to have (BH) max 20 MGOe or more, and the upper limit of each addition amount is determined to be the above value or less. The upper limit of the total amount of M when two or more types of M are added is equal to or lower than the maximum value among the upper limits of the M elements actually added. Eg T
When i, Ni, and Nb are added, it becomes 9% or less of Nb.
As M, V, Nb, Ta, Mo, W, Cr, Al and Sn are preferable. Except for some M (Sb, Sn, etc.), the addition amount of M is preferably within about 3%, preferably 0.1 to 3% (particularly 0.2 to 2).
%) Is preferred.

[0056] In the sintered magnet obtained by sintering the permanent magnet alloy of the present invention, the average crystal grain size, FeCoBR system, FeC o BR
1 to 100 μm, preferably 2 to 40 μm in any M type
m, preferred that particularly preferably in the range of about 3~10μm
Good Sintering can be performed at temperatures of 900-1200 ° C.
The aging treatment can be performed at a temperature of 350 ° C. or higher and the sintering temperature or lower, preferably 450 to 800 ° C. after sintering. The alloy powder used for sintering preferably has an average particle size of 0.3 to 80 μm (preferably 1 to 40 μm, particularly preferably 2 to 20 μm). For such sintering conditions, already No. Sho 58-88373 according to commonly owned application, are disclosed in JP 58-90039 必
Refer to it if necessary .

[0057]

EXAMPLES The magnets and effects obtained by the method for producing a permanent magnet of the present invention will be described below with reference to examples. The book
The invention is not limited to these examples. The sample was prepared by the following steps. (Purity is displayed in% by weight)

(1) A mixture having the following composition was melted by high frequency to produce an alloy, which was cast in a water-cooled copper mold.
99.9% electrolytic iron, B as ferroboron alloy (19.38%
B, 5.32% Al, 0.74% Si, 0.03% C, balance Fe), and R as purity 99.7% or more (impurities are mainly other rare earth metals)
use. (Co uses electrolytic Co with a purity of 99.9%). (2) Grinding Coarsely crushed by a stamp mill up to 35 mesh through, then finely crushed by a ball mill for 3 hours (3 ~
10 μm). (3) Orientation and molding in a magnetic field (10 kOe) (pressurized at 1.5 t / cm ² ). (4) Sintering 1000-1200 ℃ 1 hour in Ar, let cool after sintering

After processing and polishing the obtained sample, the magnet characteristics were examined by an electromagnet type magnet characteristics tester.

[0060]

[Example 1] As R, an alloy in which Nd and another rare earth element were combined was prepared and magnetized by the above steps. Heat treatment
The previous measurement results are shown in Table 1. Among the rare earth elements R, participation
Dy, Tb, Ho as shown in No. 7-9, 11-14
It was found that there is an element (R ₁ ) which has a remarkable effect on iHc improvement. Those marked with * indicate comparative examples. In addition, when the content of Co is 5% or more, the Br temperature coefficient is 0.1%.
It can be seen from Table 1 that the temperature is below / ° C.

[0061]

[Example 2] The kind and content of the rare earth elements listed in Example 1 were selected more extensively for the light rare earth elements centered on Nd and Pr, and magnetized by the above-mentioned method. Furthermore, in order to further increase the iHc increasing effect, heat treatment was performed in Ar at 600 to 700 ° C. for 2 hours. Table 2 shows the results.

Table 2, No. * 1 is a comparative example using only Nd as a rare earth element. No. 2 to No. 7 show cases where Dy was replaced with Nd. IHc gradually increases as the amount of Dy increases, but (BH) max shows the highest value around 0.4% Dy (see also Fig. 2).

[0063] According to FIG. 2, Dy began to show the effects of 0.05%, clearly by converting 0.1%, to increase the effect of the entailment iHc to increase 0.3% (the horizontal axis in FIG. 2 in log scale Become). Gd (No.11), Ho (No.10), Tb (No.12), Er (N
o.13), Yb (No.14), etc. have similar effects, but Dy, T
b is particularly effective in increasing Hc. Of R ₁ , elements other than Dy and Tb also have iHc well above 10 kOe and are high (BH)
have max. (BH) max ≧ 30MGOe class, so high
There has never been a magnetic material with iHc. Instead of Nd,
Even if Pr is used (No.15) or (Nd + Pr) out of R ₂
Even if it is 80% or more (No.16), it shows (BH) max 20MGOe or more. IHc increasing effect of R ₁ according to Figure 2 the increase in the amount of R ₁
Corresponding, but (BH) max is slightly low after passing the specified peak
Down. However, for the same R ₁ value, the
It is extremely advantageous because it increases Hc.

FIG. 3 shows the demagnetization curve of 0.8% Dy (Table 1, No. 8) having a typical iHc. It can be seen that iHc is sufficiently higher than that of the Fe-B-Nd system example (Table 1, No. 1).

[0065]

[Example 3] As additive element M, Ti, Mo, B having a purity of 99%
i, Mn, Sb, Ni, Ta, Sn, Ge, W of 98%, A of 99.9%
l, 95% Hf, ferrovanadium containing 81.2% V as V, ferroniobium containing 67.6% Nb as Nb, Cr
Ferrochrome with 61.9% Cr as and 7 as Zr
Ferro-zirconium containing 5.5% Zr was used.

These were alloyed in the same manner as described above, and then aged at 500 to 700 ° C. The results are shown in Table 3.

It is confirmed that a sufficiently high iHc can be obtained also for the FeCoBRM type alloy in which the additional element M is added to the FeCoBR type. The demagnetization curve of Table 3 and No. 1 is shown in FIG.

[0068]

[Table 1]

[0069]

[Table 2]

[0070]

[Table 3]

[0071]

[Table 4]

[0072]

As described above, the present invention provides high remanence, high coercive force,
High permanent magnets practical with high energy product are those revealed actual, yet combining predetermined _{R (R 1, R 2)} ,
By further heat treatment, its temperature characteristics (especially coercive force) are further increased while maintaining the high energy product (BH) max, and by substituting a part of Fe with Co, the Curie point is also improved for the FeBR system. It is possible to achieve an increase, and therefore has an extremely high industrial value. Furthermore, the present invention is extremely useful in that R can be mainly composed of rare earth elements such as Nd and Pr which are industrially easily available.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the Co content and the Curie point Tc when Fe is replaced by Co in one example of the alloy of the present invention.

FIG. 2 shows Nd as an R ₁ element Dy in one embodiment of the alloy of the present invention.
3 is a graph showing the relationship between Dy content and iHc, (BH) max in the case of substituting by.

FIG. 3 shows graphs showing demagnetization curves of representative examples, respectively.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location H01F 1/08 (72) Inventor Hitoshi Yamamoto 2-15-17 Egawa, Shimamoto-cho, Mishima-gun, Osaka Prefecture Tomo Special Metal Co., Ltd. Yamazaki Works (72) Inventor Masao Togawa 2-15-17 Egawa, Shimamoto Town, Mishima-gun, Osaka Sumitomo Special Metal Co., Ltd. Yamazaki Works

Claims (2)

[Claims] 1. The sum of R ₁ and R ₂ below is R (rare earth element).
In terms of atomic percentage, R ₁ 0.05 to 5%, R 12.5 to 20%, B 4 to 20%, and the balance consisting essentially of Fe.
The following was replaced with Co (excluding 0%), the permanent magnet alloy containing tetragonal crystals as a main phase having a magnetic anisotropy; (wherein, R ₁ is One or more of Dy, Tb, Gd, Ho, Er, Tm, Yb, R ₂ is one or more of Nd and Pr, or the total of Nd and Pr is 80%.
At least _{one of the} rare earth elements including Y other than R ₁ is sintered at 900 to 1200 ° C. and baked at 350 ° C. or more.
A feature of increasing the coercive force by heat treatment below the binding temperature
A method of manufacturing an R ₁ R ₂ FeCoB-based permanent magnet . _2. The sum of R ₁ and R ₂ below is R (rare earth element).
, R ₁ 0.05 to 5%, R 12.5 to 20%, B 4 to 20%, and the following predetermined% or less of one or more additive elements M (provided that M is two or more of the above additive elements). , The total amount of M is less than or equal to the atomic percentage of the additive element having the maximum value), and the balance substantially consists of Fe, and a part of the Fe is 35% or less (0% inner one (wherein, R ₁ is Dy, Tb, Gd, Ho, Er, Tm, Yb; was replaced by Co in an exception), tetragonal crystal permanent magnet alloy containing a principal phase having a magnetic anisotropy As described above, R ₂ is one or more of Nd and Pr, or the total of Nd and Pr is 80%.
The rest is at least one of rare earth elements including Y other than R ₁ , and the additive element M is as follows: Ti 3%, Zr 3.3%, Hf 3.3%, Cr 4.5%, Mn 5%, Ni 6 %, Ta 7%, Ge 3.5%, Sn 1.5%, Sb 1%, Bi 5%, Mo 5.2%, Nb 9%, Al 5%, V 5.5%, W 5% ) at 900-1200 ℃ Above 350 ° C and below the sintering temperature
R ₁ R ₂ characterized by heat treatment to increase coercive force
Manufacturing method of FeCoB type permanent magnet .