JP2886378B2 - Method for producing raw material powder for R-Fe-B-based permanent magnet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a raw material powder used for producing an R--Fe--B permanent magnet containing R (at least one of rare earth elements including Y), Fe and B as main components .
Regarding the production method , most of R ₂
A main phase alloy powder having a Fe ₁₄ B phase as a main phase, and an intermetallic compound phase of Co or Fe and R including an R ₃ Co phase obtained by a melting and pulverization method (however, one part or most of Co is Fe Intermetallic compound powder containing a part of R ₂ (FeCo) ₁₄ B phase, etc., and containing more rare earth metals than the main phase alloy powder.
By end and incorporated into the alloy powder for the magnet of the required composition at a specific ratio, R-F was significantly reduced oxygen content
The present invention relates to a method for producing a raw material powder for an e-B permanent magnet.

[0002]

2. Description of the Related Art Today, a typical high performance permanent magnet R
-Fe-B based permanent magnet (JP-A-59-46008)
Exhibits high magnet properties in a structure having a main phase of a ternary tetragonal compound and an R-rich phase, iHc of 25 kOe or more,
(BH) max is 45 MGOe or more, exhibiting remarkably high performance even when compared with a conventional high performance rare earth cobalt magnet. Further, R-Fe-B permanent magnets of various compositions have been proposed so as to exhibit various magnet properties selected according to the application.

[0003] In order to produce R-Fe-B sintered permanent magnets having the above-mentioned various compositions, it is necessary to produce alloy powders for magnets having a required composition, using a rare earth raw material reduced by electrolysis. It is melted and cast into a mold to create an alloy ingot of the required magnet composition, which is crushed to an alloy powder of a required particle size,
Dissolving and pulverizing method in which an alloy lump is caused to collapse by absorbing hydrogen, or the molten metal is sprayed and powdered (JP-A-60-633).
No. 04, JP-A-60-1190701, JP-A-60-190701
No. 189901) and a direct reduction-diffusion method for preparing a magnet composition alloy powder directly using a rare earth oxide, Fe powder, etc.
9-219404 and JP-A-60-77943.

In the melting / pulverizing method, an Fe primary crystal is liable to be generated during casting and the R-rich phase is largely segregated. However, since the ingot can be easily oxidized in the coarse crushing step, crushing can be performed.
An alloy powder having a relatively low oxygen content is obtained.

[0005] The direct reduction diffusion method has the advantage that the steps of melting and coarse grinding can be omitted when preparing the raw material powder for the magnet as compared with the melting and pulverizing method described above.
_{Since the} R-rich phase is formed around the ₂ Fe ₁₄ B main phase, and the size of the R-rich phase is small and well dispersed as compared with the former, it is easily oxidized at the time of production and the oxygen content is high. However, depending on the magnet composition, there is a problem that the rare earth element is consumed and causes a variation in magnet characteristics.

[0006]

As described above, in the production of permanent magnets using R-Fe-B-based permanent magnet raw material powders by the direct reduction diffusion method, steps such as dissolution and coarse pulverization can be omitted, and the production can be reduced. Although the R-rich phase is small and well dispersed as a characteristic of the raw material powder, it is easily oxidized,
The content of oxygen is large as compared with the melting and pulverization method raw material, and the characteristics of the magnet vary due to slight oxidation during the magnet manufacturing process.

Therefore, by adding elements such as Co and Ni to make the R-rich phase an intermetallic compound which is relatively stable against oxidation, the amount of oxygen can be reduced, but these added elements are most effective. It is impossible to add and control an optimum amount to obtain a predetermined composition.

That is, in order to obtain predetermined magnet properties, it is necessary to change the amount of one or more rare earth elements to be added to respective required values. For example, by adding a Co element, the amount of oxygen can be reduced. At this time, it is impossible to diffuse the Co element only into the R-rich phase to obtain the required phase.
The element is also replaced with Fe in the main phase. Also, Co
Elements such as Ni and Ni also have a problem of lowering the coercive force of the magnet depending on the added amount, so that the amount of oxygen cannot be easily reduced.

Conventionally, the production of raw material powders for R-Fe-B permanent magnet magnets by a dissolution / pulverization method or a direct reduction diffusion method has been carried out with a target composition corresponding to the magnet properties required at the time of melting or reduction diffusion. The composition is adjusted in advance so that

However, in the case of the dissolution / pulverization method, R ₂ F
α-Fe is crystallized as a primary crystal other than the e ₁₄ B phase, and the uniformity of the composition is impaired. On the other hand, RF by direct reduction diffusion method
In the case of the raw material powder for an eB-based permanent magnet, the raw material powder has a structure in which an R-rich phase exists around the main phase of the R ₂ Fe ₁₄ B phase.
The R-rich phase is preferentially oxidized during the production of the raw material powder to increase the oxygen content, or if a specific element is likely to enter the main phase in order to adjust to a specific composition according to the magnet properties, It is necessary to always consider the alloy composition and the composition ratio, such as whether the alloy easily enters the rich phase, and in the case of aiming for the required magnet characteristics, it is necessary to manufacture the alloy powder aiming at a composition in a specific extremely narrow range.

That is, in any of the production methods of the dissolution / pulverization method and the direct reduction diffusion method, it is not possible to adjust the abundance ratio of the R ₂ Fe ₁₄ B phase and the R-rich phase so as to attain a target composition. However, it is difficult to avoid crystallization of the α-Fe phase by the dissolution / pulverization method, and the direct reduction diffusion method has problems such as an increase in the oxygen content.

The present invention has been made in view of the above-mentioned situation of raw material powders used in the production of R-Fe-B permanent magnets, and has solved the problems in the production and production of raw material powders in the melting / pulverization method and the direct reduction diffusion method. The purpose of the present invention is to improve the quality of the present permanent magnet using raw material powders, and to manufacture alloy powders according to various required magnet properties, the R-Fe-B permanent magnets can be used by the mixing ratio of each raw material. How to make raw material powder for magnets
The purpose is to provide the law .

[0013]

SUMMARY OF THE INVENTION The present invention has been studied by various means for the purpose of reducing the oxygen content of the raw material powder for R-Fe-B permanent magnets by the direct reduction diffusion method. Focusing on the fact that the oxygen content can be reduced by reducing the rich phase or forming only the R ₂ Fe ₁₄ B main phase, R ₂ Fe ₁₄
An alloy powder having a composition close to the B phase and a composition corresponding to various magnet properties cannot be obtained only with the alloy powder having a small R-rich phase, and an R-Fe-B permanent magnet is usually used. In view of the fact that it is extremely difficult to manufacture by the powder metallurgical method of (1) because unavoidable raw material oxidation occurs during the manufacturing process, R-rich alloy powder is melted and pulverized to obtain R ₃ Co by adding Co element. Co or Fe and an intermetallic compound phase of R containing a phase (however, part or most of Co can be replaced by Fe) (however, part or most of Co is F
e) and an intermetallic compound powder composed of R ₂ (FeCo) ₁₄ B phase and the like, and by mixing both, an alloy powder having a predetermined magnet composition with a low oxygen content can be obtained. The inventors have found that it is possible to easily provide an alloy powder having a composition according to various magnetic properties of BH) max of 20 to 45 MGOe, and completed the present invention.

That is, the present invention relates to a method for producing R (where R is at least one kind of rare earth element containing Y) from 11 atomic% to 1 atomic%.
3 atomic%, B 4 atomic% to 12 atomic%, balance Fe and unavoidable impurities, or furthermore, a part of Fe is Co
R ₂ Fe ₁₄ B phase, R ₂ (FeCo) ₁₄ B phase or R ₂ (FeNi) ₁₄ B phase by direct reduction diffusion method by substituting one or two kinds of 10 atomic% or less and Ni 3 atomic% or less. An alloy powder as a main phase, 13 atomic% to 45 atomic% of R (where R is at least one of rare earth elements including Y), B
12 atomic% or less, the balance consists of Co (however, part or most of Co can be replaced by Fe) and unavoidable impurities, and is dissolved with Co or Fe containing R ₃ Co phase by a powdering method. An intermetallic compound phase with R (however, part or most of Co can be replaced by Fe) and R ₂ (Fe
An intermetallic compound Powder consisting of Co) ₁₄ B phase etc., 60-9
A method for producing a raw material powder for an R-Fe-B-based permanent magnet, characterized by being blended with a required composition of the R-Fe-B-based permanent magnet in a ratio of 7:40 to 3.

[0015]

According to the present invention, in the production of an R-Fe-B permanent magnet, R ₂ Fe having a small R-rich phase is produced by a direct reduction diffusion method.
₁₄ By making the alloy powder with a composition close to the B phase, the oxygen content can be reduced, and the R
By mixing the rich intermetallic compound powder, an alloy powder having a composition according to the required magnet properties can be easily and significantly reduced in oxygen content.

Therefore, the raw material powder for R-Fe-B permanent magnets according to the present invention can be used to a certain extent in the production of alloy powders corresponding to various required magnet properties, and can be handled by the mixing ratio. That is, the type and amount of the rare earth element are changed in accordance with various required magnet properties, and when producing a raw material alloy powder for an R—Fe—B based permanent magnet having a plurality of types of compositions, (1) direct By the reduction diffusion method, R
(Where R is at least one of rare earth elements including Y)
11 atomic% to 13 atomic%, B 4 atomic% to 12 atomic%, balance Fe and unavoidable impurities, or
part of e is Co of 10 atomic% or less, Ni of 3 atomic% or less
And the R-rich phase is 4% or less.
₂ Fe ₁₄ B phase or R ₂ (FeCo) ₁₄ B phase or R ₂
One type of alloy powder having (FeNi) ₁₄ B phase as a main phase is prepared, and (2) R (where R is at least one of rare earth elements including Y) 13 atomic% to 45 atomic% by a melting / pulverizing method. Atomic%, B12 atomic% or less, Co or Fe containing the remainder Co (however, part or most of Co can be replaced by Fe) and unavoidable impurities, and containing R ₃ Co phase.
When preparing an intermetallic compound powder consisting of an intermetallic compound phase of R and R (however, part or most of Co can be replaced by Fe) and an R ₂ (FeCo) ₁₄ B phase, etc., A plurality of intermetallic compound powders in which the ratio of the rare earth element contained in the intermetallic compound is changed in accordance with the type and the amount of the intermetallic compound; By mixing at a ratio of ~ 97: 40 ~ 3, alloy powders having a plurality of compositions according to the magnet properties can be obtained.

In the present invention, the compounding ratio of the alloy powder comprising the required main phase by the direct reduction diffusion method and the intermetallic compound powder by the melting and pulverizing method is set to 60 to 97:40 to 3 When the alloy powder composed of the required main phase is 60 wt % or less and the intermetallic compound powder is 40 wt % or more, it takes time to uniformly diffuse each element when manufacturing a magnet, and the amount of the intermetallic compound powder is 3 wt %. Below, if the alloy powder composed of the required main phase is 97 wt % or more, the liquid phase is not sufficiently developed during sintering.

Rare earth element R The rare earth element R used in the present invention is a rare earth element containing Y and including light rare earths and heavy rare earths, and at least one of them, preferably light rare earths such as Nd and Pr is mainly used. Or a mixture with Nd, Pr, or the like. That is, as R, Nd, Pr, La, Ce,
Tb, Dy, Ho, Er, Eu, Sm, Gd, Pm, T
m, Yb, Lu, and Y can be used. This R may not be a pure rare earth element, and may contain impurities that are unavoidable in production within the industrially available range.

Reason for limitation In order to obtain the alloy powder composed of the R ₂ Fe ₁₄ B main phase, R
Is less than 11 atomic%, the residual iron portion in which R and B do not diffuse increases, and if it exceeds 13 atomic%, the R-rich phase increases and the oxygen content increases, so that R is 11 atomic% to 13 atomic%. And If B is less than 4 atomic%, a high coercive force (iHc) cannot be obtained, and if it exceeds 12 atomic%, the residual magnetic flux density (Br) decreases, so that an excellent permanent magnet cannot be obtained. B is 4 to 12 atomic%. Further, the balance consists of Fe and inevitable impurities, and the content of Fe is preferably in the range of 75 to 85 atomic%.
At less than atomic%, the rare earth element becomes relatively rich, and R
When the rich phase increases and exceeds 85 atomic%, the rare earth element relatively decreases, and the residual Fe portion increases, resulting in a non-uniform alloy powder. Co and Ni in the main phase alloy powder are R ₂ F
In order to reduce the coercive force by substituting Fe in the e ₁₄ B main phase, Co is set to 10 atomic% or less and Ni is set to 3 atomic% or less. However, when a part of Fe is substituted with Co or Ni described above, Fe is in the range of 62 atomic% to 85 atomic%. R with little R-rich phase created by direct reduction diffusion method
It is desirable that the alloy powder composed of the ₂ Fe ₁₄ B main phase has no R-rich phase in order to reduce the oxygen content. However, if the content is 4 wt% or less, the reduction in the oxygen content may be greatly impaired. Absent.

The Co containing R ₃ Co phase is obtained by the dissolving and pulverizing method.
Or an intermetallic compound phase of Fe and R (however, part or most of Co can be replaced by Fe) and R ₂ (FeC
o) The intermetallic compound powder composed of the ₁₄ B phase or the like, that is, the R-rich alloy powder is made of R ₃ Co phase or R ₃ Co phase Co.
And a core part of which is replaced by Fe
o ₅ , R ₂ Co ₇ , RCo ₃ , RCo ₂ , R ₂ Co ₃ , R ₂ Fe
₁₇ , RFe _2, Nd ₂ Co ₁₇ , Nd ₅ Co ₁₉ , Dy ₆ Fe ₂ ,
DyFe or the like, and the intermetallic compound phase and R ₂ (FeC
o) Powder obtained by pulverizing an alloy composed of any of ₁₄ B, R _1.11 (FeCo) ₄ B _{4 and the} like with a pulverizer such as a disk mill. As described above, the composition of the R-rich alloy powder depends on the type and amount of the rare earth element of the target composition.
The ratio of the rare earth element contained in the intermetallic compound is changed. However, when R is less than 13 atoms, the liquid phase is not sufficiently developed during sintering when the magnet is manufactured by blending with the main phase material, and when it exceeds 45 atom%, the oxygen content increases. Inviting is not preferred. Further, Co is necessary in the R-rich intermetallic compound powder in an amount of 1 atomic% or more, preferably 3 to 20 atomic%.
And the remainder can be replaced by Fe. Further, if B exceeds 12 atomic%, B-ri besides R ₂ (FeCo) ₁₄ B phase
It is not preferable because the ch phase, the Fe-B compound and the like are excessively present.

Method for Producing Alloy Powder In order to obtain an alloy powder consisting essentially of the R ₂ Fe ₁₄ B phase, at least one kind of metal powder and / or oxide powder consisting of ferroboron powder, iron powder, rare earth oxide powder, etc. Is selected according to the desired composition of the raw alloy powder. For example, metal Ca or CaH ₂ is added to the raw material powder at a stoichiometric amount of 1.1 required for the reduction of the rare earth oxide powder.
~ 4.0 times (weight ratio) mixed in an inert gas atmosphere.
By heating to 00 ° C to 1200 ° C and pouring the obtained reaction product into water to remove a reaction by-product, a powder having an average particle size of 10 to 200 µm that does not require coarse pulverization is obtained. In order to obtain an R-rich alloy powder, alloys such as Co, Fe, B, Ni, etc. are formed by arc melting, high frequency melting or the like so that the rare earth element content in accordance with the rare earth element type and the amount of the target composition is adjusted. After being produced by dissolution, it is pulverized into a powder having an average particle size of 2 to 200 μm. In addition, a hydrogen-containing disintegration method can be used as a pulverizing method, and an atomizing method can be used to directly obtain a powder.

Blending of alloy powder An alloy powder consisting of a required main phase by direct reduction diffusion method and an intermetallic compound powder by melting and pulverizing method are mixed at 60 to 97:40.
By blending at a ratio of 3 to 3, alloy powders having a plurality of compositions according to the magnet characteristics can be obtained. The R-Fe- according to the present invention
The raw material powder for B-based permanent magnet has an oxygen content of 2000 pp
m or less, very good characteristics can be obtained. When the obtained powder is used as it is, if the particle size of the alloy powder is too large, the magnetic properties of the permanent magnet, especially high coercive force cannot be obtained, and if the average particle size is less than 1 μm,
That is, the oxidation in the press molding, sintering, and aging treatment steps is remarkable, and excellent magnetic properties cannot be obtained.
An average particle size of 80 μm is preferable, and an alloy powder having an average particle size of 2 to 10 μm is desirable for obtaining excellent magnetic properties.

Further, by using the obtained alloy powder, an excellent R-Fe having both a high residual magnetic flux density and a high coercive force is obtained.
-In order to obtain a B-based permanent magnet, the compounded raw material powder is
R12 atomic% to 25 atomic%, B4 atomic% to 10 atomic%,
Co 0.1 atomic% to 10 atomic%, Fe 68 atomic% to 80
Atomic% compositions are preferred. Furthermore, the compounded R ₂ Fe ₁₄
An alloy powder having a B phase as a main phase and / or an intermetallic compound phase of Co or Fe and R containing an R ₃ Co phase and R ₂ (F
eCo) _14B phase intermetallic compound powder, Cu
3.5 atomic% or less, S2.5 atomic% or less, Ti 4.5 atomic% or less, Si 15 atomic% or less, V9.5 atomic% or less,
Nb 12.5 atomic% or less, Ta 10.5 atomic% or less, C
r 8.5 atomic% or less, Mo 9.5 atomic% or less, W9.5
Atomic% or less, Mn 3.5 atomic% or less, Al 9.5 atomic%
Hereinafter, Sb 2.5 atomic% or less, Ge 7 atomic% or less, Sn
3.5 at% or less, Zr 5.5 at% or less, Hf 5.5
Atomic% or less, Ca 8.5 atomic% or less, Mg 8.5 atomic%
Hereinafter, 7.0 atomic% or less of Sr, 7.0 atomic% or less of Ba,
By adding and containing at least one of Be 7.0 atomic% or less, the resulting permanent magnet can have a high coercive force,
Higher corrosion resistance and improved temperature characteristics are possible.

When the composition of the permanent magnet produced by using the alloy powder according to the present invention is R11 atomic% to 25 atomic%, B4 atomic% to 10 atomic%, Co 30 atomic% or less, and Fe 66 atomic% to 82 atomic%, The resulting magnetic anisotropic permanent magnet has a coercive force _i H _C ≧ 5 kOe, (BH) max ≧ 20 MG
Oe, and the temperature coefficient of residual magnetic flux density is 0.1% / ° C. or less, and excellent characteristics are obtained. In the case where the main component of R in the permanent magnet composition accounts for 50% or more of the light rare earth metal, R12 atomic% to 20%
Atomic%, B4 atomic% to 10 atomic%, Fe 66 atomic% to 8
It shows the best magnetic properties when it contains 2 atomic% and 20 atomic% or less of Co. In particular, light rare earth metals are Nd, Pr,
In the case of Dy, the maximum value of (BH) max is 40M
GOe or more.

[0025]

【Example】

Example 1 The raw material in the direct reduction diffusion method of the main phase was Nd ₂ O ₃ (purity 9).
9%) by using 361 g, 61.4 g of Fe-B powder having a B content of 19.1%, and 665 g of Fe powder having a purity of 99%.
193 g of 99% pure metal Ca and anhydrous CaCl
₂ and 36.1 g were charged into a stainless steel container, and Ca was mixed in an Ar gas stream at 1000 ° C. for 3 hours.
Reduction and diffusion were performed. After cooling, the resulting mixture was washed with water to remove unnecessary Ca. After the obtained powder slurry is replaced with alcohol or the like, it is dried by heating under vacuum to about 100
0 g of the raw material powder was obtained. The obtained powder had an average particle diameter of about 18 μm consisting of 12.0 atomic% of Nd, 0.2 atomic% of Pr, 6.0 atomic% of B, and the balance Fe, and the oxygen content was 15%.
At 00 ppm, almost no Nd ₂ Fe
It was _14B phase.

The raw material of the R-rich intermetallic compound powder is N
132.0 g of d metal (purity 99%), 24.1 g of Dy metal (purity 99.9%), Co metal (purity 9
Using 31.5 g of 9.9%), 2.7 g of B metal (purity 99%), and 127.7 g of electrolytic iron powder having a purity of 99%, an alloy lump obtained by high-frequency melting in an Ar atmosphere was used. ,
Pulverize with a jaw crusher disc mill, average 10
300 g of a μm powder were obtained. The obtained powder was Nd21.
0 atomic%, Pr 0.2 atomic%, Dy 3.5 atomic%, Co
13.0 atom%, B5.7 atom,% balance Fe,
According to the observation results of EPMA and the like, the R ₃ Co phase (part of Co is F
e), a rare earth element, an intermetallic compound of Fe and Co, and a part of R ₂ (FeCo) ₁₄ B phase, and the oxygen content was 1000 ppm.

Using these two raw material powders, 80% of the main phase alloy powder and 20% of the R-rich intermetallic compound powder are mixed and mixed, and 13.5 atomic% of Nd, 0.2 atomic% of Pr, and 0.2% of Dy. A raw material powder composed of 6 atomic%, B 6.0 atomic%, Co 2.2 atomic% and the balance Fe was used as a starting material for the magnet. This raw material powder is crushed for about 3
μm, and the resulting fine powder is charged into a mold, oriented in a magnetic field of about 10 kOe, and about 2 t in a direction perpendicular to the magnetic field.
Molded at a pressure of on / cm ² , 15mm × 20mm × 8
mm was formed. This molded body is 1090 ° C x 3
Sintering was performed in an Ar atmosphere for a period of time, followed by aging at 500 ° C. for 2 hours. The magnet properties of the obtained test piece were Br
= 12.9 kG, (BH) max = 40.0 MGOe,
iHc = 15.75 kOe, and the oxygen content is 475
It was 0 ppm.

The above raw material powders were mixed and mixed at a ratio of 84% of the main phase alloy powder and 16% of the R-rich intermetallic compound powder, and 13.0 atomic% of Nd, 0.2 atomic% of Pr, and 0.2% of Dy. A mixed raw material powder consisting of 5 atomic%, B 6.0 atomic%, Co 1.8 atomic% and the balance Fe was used as a starting material for the magnet, and a magnet was prepared in the same process as above. The magnet properties of the obtained test piece were as follows: Br = 13.1 kG, (BH) max = 4
1.2MGOe, iHc = 14.50 kOe, and the oxygen content was 4800 ppm.

Comparative Example 1 Nd ₂ O ₃ (purity 99%) 383 g Dy ₂ O ₃ (purity 99.9%) 18.5 g Fe-B powder having a B content of 19.1% was obtained by direct reduction diffusion method. 59.8 g Co powder (purity: 99.9%): 21.4 g Fe powder having a purity of 99% was used by using 606 g.
215.6 g of metallic Ca and 40.40% of anhydrous CaCl ₂ .
7 g were mixed, charged in a stainless steel container, and reduced and diffused with Ca under a condition of 1000 ° C. × 3 hours in an Ar gas flow. After cooling, the resulting mixture was washed with water to remove unnecessary Ca. The obtained powder slurry was replaced with alcohol and the like, and then dried by heating in vacuum to obtain about 1000 g of raw material powder.

The obtained powder had a Nd of 13.5 atomic%, which was equivalent to that of the starting material powder blended at a ratio of 80% of the main phase alloy powder of Example 1 and 20% of the R-rich intermetallic compound powder.
r 0.2 at%, Dy 0.6 at%, B 6.0 at%,
Average particle size of 2.2 atomic% Co and balance Fe
m, and the oxygen content was 2500 ppm. E
In observations of PMA and the like, it was found that Co was partially substituted for the R ₂ Fe ₁₄ B phase as the main phase, and the Nd ₃ Co phase and the Nd rich phase (Nd = about 95% ) Was observed. Using this starting material powder, a magnet was prepared in the same process as in Example 1 to obtain a test piece.
= 12.1 kG, (BH) max = 33.8 MGOe,
iHc = 13.8 kOe, the magnet properties were inferior to those of the magnet of Example 1, and the oxygen content was as high as 6200 ppm.

Comparative Example 2 Electrolytic iron, ferroboron alloy, Co metal, Nd metal and Dy
High frequency melting of metal, Nd 13.5 atomic%, Pr 0.3
Atomic%, Dy 0.6 atomic%, B 6.0 atomic%, Co2.
An alloy lump consisting of 2 atomic% and the balance Fe was produced. EPM
In the observation of A etc., the main phase R ₂ Fe ₁₄ B phase has some Co
Are substituted, and the α-Fe phase of the soft magnetic phase is crystallized.
_A 3Co phase and an Nd-rich phase (Nd = about 95%) were observed.

This alloy lump was pulverized with a jaw crusher / disk mill or the like, further pulverized to about 3 μm with a pulverizer such as a jet mill, and then a permanent magnet was prepared in the same process as in Example 1. The magnet properties of the obtained test piece were Br
= 12.5 kG, (BH) max = 37.6 MGOe,
iHc = 15.5 kOe, and the magnet properties were inferior to those of the magnet of Example 1, but the oxygen content was almost equal to 4850 ppm.

Example 2 The raw materials in the main phase system direct reduction diffusion method were 127.8 g of Nd ₂ O ₃ (98% purity) and Dy ₂ O
₃ (99.9% purity) and 4.3 g, B content 19.1%
Of 23.0 g of Fe-B powder, 3.9 g of Co (purity 99.5%) powder, and 258.9 g of Fe powder of 99% purity, and 70.7 g of metal Ca of 99% purity. , Anhydrous C
13.2 g of aCl ₂ was mixed, inserted into a stainless steel container, and subjected to Ca reduction diffusion in an Ar gas flow at 1000 ° C. for 3 hours. After cooling, the resulting mixture was washed with water to remove unnecessary Ca. After the obtained powder slurry was replaced with water with alcohol or the like, it was dried by heating in vacuum. The obtained powder had Nd of 11.2 atomic% and Pr of 0.3.
Atomic%, Dy 0.4 atomic%, Co 1.1 atomic%, B6.
It has an average particle size of about 15 μm consisting of 7 atomic% and the balance of Fe. The oxygen content is 1100 ppm, and it is almost the R ₂ (FeCo) ₁₄ B phase when observed by EPMA or the like.

The raw material of the R-rich intermetallic compound powder is N
153.1 g of d metal (purity 99%), 34.1 g of Co metal (purity 99.9%), B metal (purity 99%)
%) And 131.9 g of 99% pure electrolytic iron powder.
Was used to produce a powder in the same process as in Example 1. The obtained powder was composed of 25.8 atomic% of Nd, 0.2 atomic% of Pr, C
The powder was composed of 14.2 atomic%, 2.0 atomic% of B and the balance of Fe, and had an average particle size of about 10 μm. Observation results with EPMA and the like show that the Nd ₃ Co phase (a part of Co is replaced by Fe), the Nd ₂ Fe ₁₇ phase (a part of Fe is replaced by Co), and the Nd ₂ Fe ₁₄ B phase (a part of Fe) Was replaced with Co) and the oxygen content was 1000 ppm.

Using these two raw material powders, 80% of the main phase alloy powder and 20% of the R-rich intermetallic compound powder are blended and mixed, and 13.7 atomic% of Nd, 0.3 atomic% of Pr,
A raw material powder composed of 0.3 atomic% of Dy, 3.4 atomic% of Co, 5.8 atomic% of B, and the balance Fe was used as a starting material for the magnet. The magnet properties of a test piece obtained by preparing a magnet in the same process as in Example 1 were as follows: Br = 13.1 kG, (BH) max
= 41.5 MGOe, iHc = 12.85 kOe, and the oxygen content was 4100 ppm.

Example 3 A raw material for the main phase direct reduction diffusion method was prepared under the same conditions as in Example 1, and the obtained powder was 11.8 atomic% of Nd.
An average particle size of about 0.3 atomic% of Pr, 0.4 atomic% of Dy, 1.1 atomic% of Co, 6.8 atomic% of B, and the balance of Fe is about 15
The content of oxygen is 1100 ppm at μm.

The raw material of the R-rich intermetallic compound powder is Nd
169.6 g of metal (purity 99%), 23.2 g of Dy metal (purity 99.9%), and Co metal (purity 99.9%).
9%) and 3.2 parts of B metal (purity 99%).
g, Cu metal (purity 99.9%), 2.4 g, purity 9
Using 102.0 g of 9% electrolytic iron powder, a powder was prepared in the same process as in Example 1. The resulting powder was Nd30.5
Atomic%, Pr 0.2 atomic%, Dy 3.6 atomic%, Co
The average particle size of 9.0 atomic%, B 8.0 atomic%, Cu 0.7 atomic% and the balance Fe was 10 μm, and the oxygen content was 1100 ppm.

Using these two raw material powders, 90% of the main phase alloy powder and 10% of the R-rich intermetallic compound powder are mixed and mixed, and 13.2 atomic% of Nd, 0.3 atomic% of Pr, and 0.3% of Dy. 6 atomic%, Co 1.7 atomic%, Cu 0.1
A blended raw material powder consisting of atomic%, B 7.1 atomic% and the balance Fe was used as a starting material for the magnet. This raw material powder is finely pulverized to about 3 μm with a pulverizer such as a ball mill, and the obtained slurry fine powder is charged into a mold, oriented in a magnetic field of about 10 kOe, and about 1.5 ton / cm in a direction perpendicular to the magnetic field. Molding was performed at a pressure of ² to prepare a molded body of 15 mm × 20 mm × 8 mm. The residual solvent is removed from the molded body in a vacuum,
Sintering in an Ar atmosphere at 090 ° C. × 3 hours, 500
An aging treatment was performed at 2 ° C. for 2 hours. The magnet properties of the obtained test piece were Br = 12.5 kG, (BH) max = 38.
5MGOe, iHc = 17.0.5 kOe, and the oxygen content was 3500 ppm.

[0039]

According to the present invention, an alloy powder having a composition close to that of an R ₂ Fe ₁₄ B phase having a small R-rich phase is produced by a direct reduction diffusion method, and an R-rich intermetallic compound is produced by a dissolution / pulverization method. The alloy particles may be prepared by adding the Co element to the R ₃ Co phase or an R ₂ (FeCo) ₁₇ phase and an R ₂ (FeCo) ₁₄ B phase in which a part of Co of the R ₃ Co phase is replaced by Fe. By preparing an intermetallic compound alloy powder composed of an intermetallic compound phase and mixing them at a specific ratio , it is possible to easily obtain a predetermined magnet composition alloy powder having a low oxygen content and high magnetic properties. . Further, the present invention is to change the rare earth element species and their amounts according to the required several kinds of magnet properties, when producing a raw alloy powder for R-Fe-B based permanent magnet consisting of a plurality of compositions, For example, one kind of main phase alloy powder having a required composition, and a plurality of kinds of intermetallic compound powders produced by changing the rare earth element content ratio of the intermetallic compound according to the rare earth element species and the amount of the target composition. By blending, it is possible to easily obtain an alloy powder having a plurality of compositions according to the required magnet properties.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-250607 (JP, A) JP-A-61-238903 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01F 1/06 B22F 1/00 C22C 19/07 C22C 38/00 303

Claims (2)

(57) [Claims] 1. R (where R is at least one of rare earth elements including Y) 11 to 13 at%, B 4 at%
~ 12 atomic%, balance Fe and unavoidable impurities,
An alloy powder having a main phase of R ₂ Fe ₁₄ B phase by direct reduction diffusion method, and 13 atomic% to 45 atomic% of R (R is at least one of rare earth elements including Y), 12 atomic% or less of B, and the balance Co (but part or most of Co can be replaced by Fe) and inevitable impurities, and an intermetallic compound phase of Co or Fe and R (including R ₃ Co phase) by a dissolution / pulverization method. 1 part or most of the possible substitutions at Fe) and R ₂ (FeCo) ₁₄ intermetallic compounds powder consisting of B equality of Co, 60~97: R-Fe- B based permanent at a ratio of 40-3 Method for producing raw material powder for R-Fe-B-based permanent magnet, characterized in that it is blended with the required composition of magnet
Law . 2. R (where R is at least one of rare earth elements including Y) 11 to 13 at%, B 4 at%
One or two kinds of １２12 atomic%, Co 10 atomic% or less, Ni 3 atomic% or less, the balance being Fe and unavoidable impurities, and R ₂ (FeCo) ₁₄ B phase or R ₂ (FeNi) ₁₄ by direct reduction diffusion method An alloy powder having a B phase as a main phase;
(Where R is at least one of rare earth elements including Y)
13 atomic% to 45 atomic%, B 12 atomic% or less, balance Co
(However, part or most of Co can be replaced by Fe) and unavoidable impurities, and an intermetallic compound phase of Co or Fe and R containing R ₃ Co phase (however, Co 1 part or most of the possible substitutions at Fe) and R ₂ (FeCo) intermetallic compound powder consisting of ₁₄ B equality of 60 to 97: at a ratio of 40-3 R-Fe
A method for producing a raw material powder for an R-Fe-B-based permanent magnet, wherein the raw material powder is blended in a required composition of a -B-based permanent magnet.