JPS624807A - Production of alloy powder for rare earth magnet - Google Patents

Abstract

PURPOSE:To obtain alloy powder contg. O2, C and Ca at low ratios and having excellent magnetic characteristics by mixing respective powders of Fe, B and rare earth which are controlled in grain size to a specific ratio, subjecting the mixture to a reduction diffusion treatment and subjecting the resulted product thereof to slurrying and water treatments in a cooled ion exchange water. CONSTITUTION:The rare earth oxide powder, the iron powder and pure boron powder having <=150mu grain size, ferroboron powder and boron oxide, etc. are mixed in such a manner that the powder mixture contains 12-20atom% R (Nd, Pr, Dy, Ho, Tb, etc.), 4-20% B and 65-81% Fe. Metallic Ca of 1.5-3.5 times the stoichiometrical requirement of the oxygen content in the raw material powder and CaCl2 of 1-15wt% of the weight of the raw earth oxide are compounded with such powder mixture. The compounded powder is heated to 900-1,200 deg.C in an inert gaseous atmosphere and is subjected to the reduction diffusion treatment. The resulted product is introduced into the ion exchange water cooled to <=15 deg.C and is slurried; further the product is removed of the Ca-component by the ion exchange water kept at <=15 deg.C and is then vacuum-dried. The alloy powder for a rare earth magnet of which the main crystal is of a tegragonal crystal phase and contains <=4,000ppm O2, <=600ppm C and <=100ppm Ca is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application The present invention relates to a method for producing FeBR based alloy powder for permanent magnets, which enables a predetermined particle size to be obtained without melting or mechanical pulverization, and which can be easily manufactured by 'I'. The present invention relates to a method for producing alloy powder for rare earth magnets, which is a production method using a Ca reduction method that can reduce the amount of impurities such as oxygen that deteriorate the magnetic properties of the final product.

BACKGROUND ART Current typical permanent magnet materials are alnico, hard ferrite and rare earth cobalt magnets.

Among these, rare earth cobalt magnets have extremely excellent magnetic properties and are used for a variety of purposes, but their main components, Sm and Co, are both scarce and expensive, and will continue to be used for a long time. It is difficult to stably supply large amounts of it. Therefore, there has been a strong need for a permanent magnet material that has excellent magnetic properties, is inexpensive, has abundant resources, and has constituent elements that can be stably supplied in the future.

The present applicant previously proposed a Fa-B-R system (R is at least one rare earth element including Y) permanent magnet as a new high-performance permanent magnet that does not contain expensive Sm or % (Unexamined Japanese Patent Publication No. 59-460()8, JP-A-59-64733, JP-A-59-89401, JP-A-59-13210
No. 4).

This permanent magnet uses resource-rich light rare earth materials such as ceramics and circles as R, and is made of 15 M with Fs as the main component.
It is an excellent permanent magnet that exhibits an extremely high energy product exceeding G Os.

In addition, as a method for producing alloy powder for rare earth magnets in order to provide even higher magnetic properties to this Fa-B-R permanent magnet and to produce it at low cost, the applicant has previously developed a method using a Ca reduction method. proposed a manufacturing method (Japanese Patent Application No. 59-219404), and further proposed a manufacturing method for alloy powder for rare earth magnets by Ca reduction with reduced oxygen, carbon, and calcium contents (Japanese Patent Application No. 59-182574, Gansho 59-248
No. 798).

The gist is that R (R is m, Pr, Dy, Ho,
At least one of Th or further, La, C
8, Sm.

(consisting of at least one of J, Er, Eu, Tom, Yb, Li, Y) 12.0 atom% to 20 atom%, B4 atom% to 20 atom%, Fe80 atom% to 83
At least 1 of the rare earth oxides so that the atomic %
Seeds and iron powder.

The amount of oxygen contained in the raw material powder such as the rare earth oxide in a mixed powder in which at least one of pure boron powder, ferroboron powder, and boron oxide, or an alloy powder or mixed oxide of the above constituent elements is blended into the above composition. Gold RCa in an amount of 1.5 to 3.5 times (weight ratio) the stoichiometric required amount and 1 wt% to 15 wt% of rare earth oxide CaCl2 were mixed and heated at 900°C in an inert gas atmosphere. This is a method for producing alloy powder for rare earth magnets, in which reduction and diffusion is carried out at ~1200°C, the obtained reaction product is put into water to form a slurry, and the slurry is further treated with water.

With the above technology, the amount of oxygen is less than soooppm, the amount of carbon is less than 100ppm, and the amount of Ca is 2000pl)m
Under JJ (DFa-E3-R series permanent Fj1EJ alloy powder is obtained, and a Fe-B-R series permanent magnet with excellent magnetic properties is obtained. However, in order to obtain even better magnetic properties, the above contents must be Further reduction was necessary.

In addition, in the above Ca reduction method, we have further improved the yield of raw material powder during reduction and diffusion, homogenized the composition of the produced alloy powder, and further improved the magnetic properties when magnetized using the alloy. It is desired that no variations occur.

Purpose of the Invention This invention provides permanent Fa-B-R system! The aim is to produce a rare earth magnet alloy powder using a Ca reduction method that can improve the magnetic properties of a single stone.
We have developed an alloy powder for rare earth magnets that can significantly reduce the amount of oxygen, carbon, and calcium in alloy powder for stone, improve the efficiency of reduction and diffusion, and homogenize the unstructured structure of finely matched gold powder, resulting in excellent magnetic properties. It is intended for manufacturing methods.

Structure and Effects of the Invention The content of oxygen, carbon, and calcium in the rare earth single-stone alloy powder greatly influences the properties of the obtained permanent magnet, so it is essential to reduce the content.
In a-reduction, when the reaction product obtained by Ca reduction/diffusion is slurried and treated with water, the properties of the treated water greatly affect the amount of oxygen, carbon, and calcium in the produced alloy powder. It was found that the oxidation of

As a result of various studies on the manufacturing method of alloy powder that can improve the magnetic properties of the Fe-B-R permanent magnet 5, the inventors found that
The reaction product obtained by Ca reduction and diffusion is made into a slurry,
By using ion-exchanged water cooled to 15°C or less during water treatment, the content of oxygen, carbon, and calcium in the alloy powder can be greatly reduced, and the coercive force of the Fa-B-R permanent magnet material Furthermore, the present invention was completed based on the finding that the squareness of the demagnetization curve could be improved.

That is, this invention provides R (R is at least one of Nd, Pr, Dy, Ho, Tb, or furthermore, La, Co, Sm
, CtJ, Er, Eu, Dingm.

consisting of at least one of Yb, La, Y)1
The main components are 2 atomic % to 20 atomic %, B44 atomic % to 20 atomic %, and Fe 65 atomic % to 81 atomic %, the main phase is a tetragonal phase, the content of oxygen is 4000 pI)m or less, and the content of carbon is 600 ppm or less , in the production of alloy powder for rare earth magnets having a Cal content of 1000 ppm or less, at least one of the rare earth oxides and a particle size of 1501XrI
A mixed powder containing at least one of the following iron powder, pure boron powder, ferroboron powder, and boron oxide, or an alloy powder or mixed oxide of the above constituent elements, and an additional element powder with a particle size of 150I or less in the above composition. , 1.5 to 3.5 times the stoichiometrically required amount of metal Ca to the amount of oxygen contained in the raw material powder such as the rare earth oxide.
and 1wt% to 15wt% of rare earth oxide CaCR2 are mixed and heated to 900'C to 1200°C in an inert gas atmosphere to perform reduction diffusion, and the obtained reaction product is cooled to 15°C or less. This is a method for producing an alloy powder for rare earth magnets, which is characterized in that the powder is poured into ion-exchanged water, reacted with water to form a slurry, and the slurry is roughly treated with ion-exchanged water cooled to 15° C. or lower.

The alloy powder according to the present invention is an intermediate raw material in the preliminary stage of producing rare earth metals, that is, inexpensive light rare earth oxides such as Nd 203 and Prs O+t, and heavy rare earth oxides such as Tb30a and DV203, and a particle size of 150 or less. F+s powder and pure boron powder (either crystalline or amorphous), Fe- with a particle size of 1501.1m or less
The starting material is boron oxide such as 8 powder or e2o3 powder, metal Ca is used as a reducing agent, and CaCR2 is used to facilitate the disintegration of the reduction reaction product. It is cheaper and has higher quality than conventional magnets, can improve the magnetic properties of Fe BR permanent magnets, and is ideal for industrial mass production.

The rare earth alloy powder according to the present invention can be used to obtain a permanent magnet by a powder metallurgy manufacturing method in which it is finely pulverized as it is, press-formed, sintered and subjected to two aging treatments. Compared to the ingot crushing method, which uses raw material lumps such as iron and boron as raw materials, raw material melting and casting.

It is possible to omit manufacturing processes that require time and cost such as coarse pulverization, and as mentioned above, it uses inexpensive starting materials such as rare earth oxides and has a high yield of raw material powder.
Fa-B has reduced the price of permanent magnets, and in particular has excellent magnetic properties with no variation due to the low oxygen content in the powder and improved homogenization of the composition.
-It has the advantage that R-based permanent magnets can be mass-produced at low cost.

Fa-B- obtained using the alloy powder according to the present invention
R-based permanent magnets have (B H) maX 20MGOa or more! HC10koe or more, square shape Hk 8kO
It has magnetic properties of s or more, has little variation in properties, and maintains these properties, so it can be used in a sufficiently stable manner even in an atmosphere with a temperature of 1000 yen or more. In addition, the squareness Hk is the magnetic field H when the magnetic flux density B becomes 90% of the residual magnetic flux density Br.
is the value of

Reasons for Limiting the Invention The manufacturing process of the alloy powder for rare earth magnets according to the present invention is as follows, and the reasons for the limitations will also be explained.

First, Nd oxide (Ndz03) and yen oxide (Pr6
At least one light rare earth oxide, such as Tb oxide (Tb30c>) or N oxide (~
At least one type of heavy rare earth oxide such as 203) and at least one type of boron oxide such as Fa powder with a particle size of 150 or less and pure boron powder, ferroboron y1 (Fe-B powder), and 8□03 powder. The powder is composed of R12 at % to 20 at %, B44 at % to 20 at %, Fe65 at % to 81 at % (here, R is at least one of m, Pr, u, l(o, Tb) or further, La, Ce,
Sm, Gd, Er.

At least one of Eu, Dingm, Yb, La, Y
(consisting of seeds), and if necessary, adjust the particle size to 150.
Addition of additional elements as metal powders, oxide powders (including mixed oxides with constituent elements), alloy powders (including mixed oxides with constituent elements), or other Ca-reducible compound powders listed below. and make a raw material mixed powder.

Note that V, TL, and Zr are used as alloys with constituent elements.

There are borides such as Ta, Ta, and No.

In this invention, in order to promote the reduction reaction with the rare earth oxide and the diffusion reaction with the raw material powder to proceed uniformly and sufficiently, and to obtain a homogeneous, single-phase alloy powder with a low oxygen content, Fs powder, pure boron powder, ferroboron powder (F
At least one raw material powder or various additive elements among boron oxides such as @-B powder) and B2O3 powder must have a particle size of 150 g or less, preferably 7
Stay below 5K.

Similarly, the average particle size of the rare earth oxide in the mixed powder is 1 to 10I
Furthermore, the average particle size of the raw material powder is 1 to 15 m.
It is most desirable that the value is 2 to so and n in the case of 0 proof.

Roughly, metallic Ca powder as a rare earth element reducing agent and CaCRz'FA powder to facilitate the disintegration of the reduction reaction product are added to the raw material mixed powder. The required amount of metallic Ca is 1.5 to 3.5 times the stoichiometric amount of oxygen contained in the raw material powder such as rare earth oxide,
CaCb is Iwt% to 15wt% of the rare earth oxide.

Since the alloy powder according to the present invention contains B as an essential element, for example, the melting point of the raw material powder ferroboron powder is 100°C to 400°C lower than that of iron powder, so the rare earth element during the reduction reaction However, if the amount of Ca added is less than 1.5 times the stoichiometric amount required to reduce the rare earth oxide used, the rare earth oxide is not sufficiently absorbed. Since it is not reduced, the alloy powder contains a large amount of oxygen, making it impossible to obtain a predetermined alloy powder composition.

On the other hand, Ca is a reaction byproduct produced during the reduction reaction.
O suppresses crystal grain growth during the reduction reaction of the alloy powder, thereby making it possible to obtain an alloy powder having a predetermined average grain size. However, an excess of Ca reducing agent exceeding 3.5 times the stoichiometric amount needed to reduce rare earth oxides not only increases the cost of the process but also , causing a radical exothermic reaction between CaO and H2O,
This is not preferable because the amount of oxygen in the obtained alloy powder increases, and the amount of residual Ca in the obtained alloy powder increases.
For this reason, the magnetic properties of the permanent Fli stone to be manufactured will be low, so the upper limit is set at 3.5 times.

In addition, in order to sufficiently reduce rare earth oxides, obtain alloy powder for magnets having a predetermined average particle size, low oxygen content, low residual Cal, and a predetermined composition with a high yield, it is necessary to The amount of reducing agent is 1.5 of the stoichiometric requirement.
The most preferred case is ~2°5 times.

When the amount of Ca (Jz exceeds 15 wt% of the amount of rare earth elements), when the reduction/diffusion reaction product is treated with ion-exchanged water at a specific temperature, the CR- in the water increases significantly, and the generated rare earth alloy powder The amount of oxygen in the powder increases by 40,001)
l) If it is 111 or more, it cannot be used as an alloy powder for Fs B-R permanent magnets, and if it is less than 1wt3,
Even if the reduction/diffusion reactant is put into the ion exchange water,
Because it does not disintegrate and cannot be treated with the ion-exchanged water,
The content is set at 1 wt% to 15 wt%.

The above-mentioned rare earth oxide and Fs with a particle size of 15011I or less
After blending a predetermined amount of raw material powder such as powder and reducing agent, for example, V
Mixing is performed in an inert gas atmosphere using a mold mixer or the like. Next, the mixed powder is allowed to undergo a reduction/diffusion reaction in an inert gas flow atmosphere at a temperature range of 9()O<0>C to 1200'G for 0.5 to 5 hours. At this time,
The heating rate is preferably 5'C/min or less in order to remove adsorbed moisture gas components contained in the starting material powder.

Here, the reason why the reduction temperature was limited to 900°C to 1200°C is because below 900°C, the reduction of the rare earth oxide by Ca becomes insufficient, making it impossible to obtain an alloy powder with a predetermined composition. This is because the content of oxygen increases, which is undesirable. Also, if the reduction temperature exceeds 1200°C, the diffusion reaction during reduction will be promoted too much, causing grain formation and growth, resulting in the reduction of the grain size to a predetermined average grain size. This is because alloy powder cannot be obtained and the amount of Ca remaining in the reaction product increases, which is not preferable as alloy powder for permanent magnets. Also,
In order to obtain a high-performance permanent magnet alloy powder having a predetermined average particle size and component composition, and a low content of oxygen and residual Ca, a reduction temperature of 900° C. to 1 ioo° C. is most desirable.

In the reduction/diffusion reaction by Ca, the molten rare earth metal reduced by Ca immediately becomes grain size 150. It can be very easily and homogeneously alloyed with F8 powder or Fθ-B powder of less than a, and the alloy powder used can be recovered from the rare earth oxide with a high yield.

At the end of the reduction/diffusion reaction, the reaction may be furnace cooled or rapidly cooled to room temperature, but the cooling atmosphere is preferably in an inert gas so as not to oxidize the obtained alloy powder. It is also good to use the reaction product after crushing it in advance.

The obtained reduction reaction product was poured into ion-exchanged water cooled to 15°C or lower, and the reaction by-products CaO and CaO
2CaCJz is reacted with Ha0 to form Ca(DH)2, that is, the reduction reaction product obtained by blending 1.5 to 3.5 times the stoichiometric amount of reducing agent is , it generates heat and spontaneously collapses into a slurry state.
It has the advantage of not requiring special mechanical grinding. This slurry was further treated to sufficiently remove Ca using ion-exchanged water cooled to 15°C or lower, and roughly dried under vacuum at room temperature for 10-500°C. F-BR alloy powder for permanent magnets is obtained.

In this invention, the reaction products after reduction and diffusion are made into a slurry, and ion-exchanged water cooled to below 15°C is used as the treated water. CI in alloy powder”, NO
3-, CO3--, 5O4- and other anions are removed,
This is to prevent oxidation of the powder and further prevent the formation of poorly soluble Ca salts, and by cooling to 15°C or less, the 02 concentration in the raw material powder can be reduced.

By reducing Ca11 degrees and continuous magnetization treatment, (B
H) max > 20) IGOa, iHc > 10 k
It is possible to obtain excellent 11-stone characteristics with oe and squareness Hk > 8 koe.

The alloy powder according to the present invention obtained by the production method detailed above is composed of R (R is at least one of Nd, Pr, Dy, Ha, Tb, or at least one of La, Ce, St).
n, Gd, Er, Eu, Tm.

consisting of at least one of Yb, La, Y)1
The main components are 2 atom% to 20 atom%, B44 atom to 20 atom%, Fe65 atom% to 81 atom%, the main phase is a tetragonal phase, the content of oxygen is 4000 ppm or less, the content of carbon is 600 ppm or less, The amount of Ca is 11,000 pp or less.

The oxygen contained in the alloy powder is undesirable because it combines with the rare earth element that is most easily oxidized to form a rare earth oxide and remains in the permanent magnet as an oxide R2O3.If the oxygen amount exceeds 4000 ppm, the squareness <8k
It becomes oe.

Moreover, if the carbon content exceeds 600 ppm, the coercive force squareness will significantly deteriorate, which is not preferable.

In addition, if the Ca content exceeds 11,000 pp, a large amount of extremely highly reducing Ca vapor will be generated during the sintering process during magnetization using this alloy powder in the flame continuation process.
This is not preferable because it significantly damages the heat treatment furnace, lacks stability in industrial production, and increases the amount of residual Ca in the permanent magnet, deteriorating the magnet properties.

Reasons for limiting the components of permanent magnets The rare earth element R in the rare earth alloy powder of the present invention accounts for 12 at % to 20 at % of the composition, but tb, Pr.

~, l- +, at least one of Th, or roughly, La, Ce, Sm, (<, Er, Eu
, Tm, yb, La, and Y.

Also, normally one type of R is sufficient, but in practice two types are sufficient.
A mixture of more than one species (Mitushmetal, Didim, etc.) can be used for reasons such as availability.

Note that this R does not have to be a pure rare earth element, and may contain impurities that are unavoidable in production within an industrially available range.

R is an essential element in the new FeBR permanent magnet, and if it is less than 12 at%, the crystal structure changes to α-
Because it has a cubic structure with the same structure as iron, it is difficult to obtain high magnetic properties, especially high coercive force, and if it exceeds 20 atomic %, R-rich nonmagnetic phase increases and the coercive force is 10 koe or more, but , the residual magnetic flux density Br decreases, making it impossible to obtain a permanent magnet with excellent characteristics.

Therefore, the rare earth element is in the range of 12 atomic % to 20 atomic %.

B is an essential element in FeBR permanent magnets, and when it is less than 4 atomic %, the rhombohedral structure becomes the main phase, and a high coercive force of 1l-(c is not obtained, it becomes less than 10 koe, and 20 When it exceeds atomic%, the B-rich nonmagnetic phase increases, the residual magnetic flux density [3r decreases, and (B H)m
aX 20) less than IGOe, making it impossible to obtain an excellent permanent magnet. Therefore, B is in the range of 4 at.% to 20 at.%.

Fe is an essential element in the new above-mentioned permanent magnet, and if it is less than 65 at%, the residual magnetic flux density 3r decreases, and the
If it exceeds 1 atomic %, high coercive force cannot be obtained, so F
The content of e is 65 atomic % to 81 atomic %.

In addition, in the permanent magnet material according to the present invention, replacing a part of F8 with arm can improve temperature characteristics and corrosion resistance without impairing the magnetic properties of the resulting magnet, but G substitution If the amount exceeds 30% of Fe, the magnetic properties will deteriorate, which is undesirable.
20% or less.

In addition, the permanent magnet according to the present invention includes R, B, Fa, and other magnets.
Although the presence of unavoidable impurities in industrial production can be tolerated, B
4.0 at% or less of C13, 5 at% or less of P
, at least one of the following: 2.5 atomic % or less S, 1.5 atomic % or less 5, 5 atomic % or less SL, the total amount is 5.0
By substituting at atomic % or less, it is possible to improve the manufacturability and reduce the cost of permanent magnets.

Furthermore, at least one of the following additional elements is R-B-
It can be added to Fe-based permanent magnets because it is effective in improving the coercive force and squareness of the demagnetization curve, improving manufacturability, and reducing costs. However, addition to improve coercive force causes a decrease in residual magnetic flux density (Br), so it is desirable to add in a range that is equal to or higher than the residual magnetic flux density of conventional hard ferrite magnets.

A1 of 5.0 atomic % or less. Moon of 3.0 atomic % or less, 5.
5 at% or less V, 4.5 at% or less Cr, 5.0 at% or less Hn, 5.0 at% or less Bi, 9.0
Nb below 7.0 atom%, Ha below 5.2 atom%, -11.0 atom% below 5.0 atom%
The following sb, 3.5 atom % or less Ge, 1.5 atom % or less Sn, and 3.3 atom % or less Zr.

6.0 at% or less Ni, 1.1 at% or less Zn, 3
．． Hf of 3 atomic % or less, at least one of the following is added.However, if two or more types are contained, the maximum content is 3 atomic % or less of the one having the maximum value among the added elements.
It becomes possible to increase the coercive force of permanent magnets. Particularly preferable additive elements are V and Nb.

Ta, )io, W, Cr, AI, the content is preferably a small amount, 3 atomic % or less is effective, and 〃 is 0.1 to 3 atomic %, preferably 0.2 to 2 atomic %. .

These additional elements can be added to the starting raw material mixed powder in the form of metal powder, oxide, alloy powder with constituent elements, compound powder or mixed oxide, or compound reducible with Ca.

It is essential that the main crystal phase (80% or more of a specific phase) be tetragonal in order to obtain a fine and uniform alloy powder that can exhibit high magnetic properties as a magnet. This magnetic phase is F
It is composed of e2 R tetragonal compound crystals, and the grain boundaries are surrounded by a nonmagnetic layer. The nonmagnetic phase mainly consists of an R-rich phase, and if there is a large amount of B, a B-rich phase may also be partially present. The presence of grain boundary regions in the nonmagnetic layer is thought to contribute to high properties and is an important structural feature of the alloy of the present invention, and even a small amount of solder is effective; for example, IVO of 1% or more is sufficient It is four.

Further, the permanent magnet of the present invention can be press-molded in a magnetic field to obtain a magnetically anisotropic magnet, and press-molded in a non-magnetic field to obtain a magnetically isotropic magnet.

Permanent 1a5 according to this invention has a coercive force C≧10 kO
e, the residual magnetic flux density Br > 9 kG, and the maximum energy product (13+-1) max is (B)l ) max ≧ 208 GOs in the most preferred composition range, and the maximum value reaches 30) IGOs or more.

In addition, in the case where the main component of R in the alloy powder for permanent magnets of this invention is 50% or more of light rare earth metals mainly consisting of M and circles, R12 to 20 at%, B44 to 20
When the main component is Fe 74 at% to 80 at%, it exhibits excellent magnetic properties of (BH)ma
The maximum value reaches 428 GOe or more.

Examples Example 1 Nd203 powder 154.7(]Dso2
03 Powder
17.3 (], Fe powder (particle size 70m or less)
227.5 g ferroboron powder
23. (NJ (particle size 70pm or less, 19.58-Fe alloy powder) metal Ca powder 170.8g (
2.4 times the stoichiometric amount required for reduction) CaCJ2 powder 7. Og (3.
5wt%) Using a total amount of 600g of the above raw material powder, 30.5Ncl-
3,6Dy -1,15B -64,75Fs (wt%
), the mixture was mixed in an Ar gas atmosphere using a V-type mixer.

Next, the above-mentioned mixed powder was subjected to a reduction-diffusion reaction in an Ar gas atmosphere in a reduction furnace under conditions of 1050° C. and 2.01118°C, and then cooled to room temperature in the furnace.

600 g of the obtained reduction reaction product was poured into ion exchange water cooled to 7°C at 62°C to form a slurry, and then the slurry alloy powder was washed several times with ion exchange water cooled to 1°C. This was further vacuum-dried to obtain 351.7 g (yield: 90%) of an alloy powder according to the present invention.

The obtained alloy powder had the following composition: Nd 30.2vt%, Dy 3.4vt%, 81.
07 vt%, Fe 62.2wt%, 02 240
0ppm, C490ppm SCa 500pp
m.

The average particle size was 89 mm.

This alloy powder was finely pulverized to obtain a finely pulverized powder with an average particle size of 2.8 μm, oriented in a magnetic field of 10 KOθ, pressure molded at 1.5 tJ to form a size of 15 mm x 161 T1 m x 10 mnn, and in contact with it, in an Ar atmosphere. Inside 1080'C, 2
Sintered at 800°C in Ar
A two-stage aging treatment of 1 hour and 630°C x 1 hour was performed to obtain a permanent magnet.

The magnetic properties of the obtained permanent magnet were measured, and the results are shown in Table 1.

Also, for comparison, Nd2o3 powder 178.9g ~ 203
Powder 17.3iJ, Fθ powder (particle size 150-70Jrn) 21B, 7p ferroboron powder 21.9Q (particle size 150-701Jrn
, 19.58-Fe alloy powder) Metallic Ca powder
162.9g (2 stoichiometrically required amount for reduction)
．． 4 times) CaCf12 powder 7.0g
(3.5 needles % of rare earth oxide raw material) The manufacturing method under the above conditions except that the above raw material powder total amount of 600 g was used, the temperature of ion exchange water was set to 20'C, it was made into a slurry, and further washed. The alloy powder obtained in (3
26.7g, yield 81%), Nd30.5wt%, D
y 3.4wt%, B 1.10vt%, Fa
62.6wt%, Oe 8800ppm, C67
0DDm, Ca 8001)l)m.

The average particle size was 1571 Jm.

This comparative alloy powder was magnetized under the conditions described above, and its magnetic properties were measured. The results are shown in Table 1.

Table 1 Example 2 Nd203 powder 178.9(]Dso2
03 powder 5.8 g, Fe powder (particle size 70 ALrn or less > 226.2 g Ferroboron powder 21.3 g (particle size 7011 rH
Hereinafter, 19.58-Fe alloy powder) Ferroniobium powder
3,4q (particle size 70 Atm or less, 67.6N
b-Fe alloy powder) Metal Ca powder 15
7.9 g (2.4 times the stoichiometric amount required for reduction)C
a (J2 powder 6.5q (3.5 wt% of rare earth oxide raw material) Using the above raw material powder total amount of 600 g, 30.5M-1
,2Dy-0,6Nb-1,1B-66,6Fe(
wt%) using a V-type mixer in an Ar gas atmosphere.

Next, the above-mentioned mixed powder was subjected to a reduction-diffusion reaction in an Ar gas atmosphere in a reduction furnace at 1050° C. for 2.0 hours, and then cooled to room temperature in the furnace.

The obtained reduction reaction product 600 () was poured into ion-exchanged water cooled to 7°C in 6z to form a slurry, and then the slurry-like alloy powder was further mixed several times with ion-exchanged water cooled to 7°C. The alloy powder according to the present invention was obtained by washing and vacuum drying.

The obtained alloy powder (380.7 g, yield 93%) had the following composition: Nd 30.7 wt%, Dy 1.16 wt%, Nb
0.6wt%, 8 1.08wt%, Fe6
3.6wt%, 02 2300ppm, C510D
Dm, Ca 400 ppm.

The average particle size was 85.4 m.

This alloy powder was finely pulverized to have an average particle size of 2.8. Finely pulverized powder was obtained, oriented in a magnetic field of 10 KOθ, pressure molded at 1.5 t and J to form a size of 15 mm x 16 nur + x 10 mm, and then ttoooc in an Ar atmosphere.
Sintered at 800'C in Ar for 2 hours.
A two-stage aging treatment of X 1 Hr and 630'CX 1 Hr was performed to obtain a permanent VII stone. The magnetic properties of the obtained permanent magnet were measured, and the results are shown in Table 2.

Also, for comparison, Fe powder and ferroboron powder.

Ferroniobium powder with particle size from 1501Xn to 7011m
The alloy powder (347.9Q, yield 85%) obtained by the manufacturing method under the above conditions except that Nd30.6 powder was used.
wt%, Dy 1.16wt%, NbO, 6wt
%, B 1.07 vt%, Fe 63.5 wt%
, 022500pI)m , C4901)I)m S
Ca 500ppm.

The average particle size was 147 mm.

This comparative alloy powder was magnetized under the conditions described above, and its magnetic properties were measured. The results are shown in Table 2.

Table 2

Claims (1)

[Claims] 1 R (R is at least one of Nd, Pr, Dy, Ho, Tb, or furthermore, La, Ce, Sm, Gd,
At least one of Er, Eu, Tm, Yb, La, Y
The main components are 12 atomic % to 20 atomic %, B4 atomic % to 20 atomic %, and Fe 65 atomic % to 81 atomic %, the main phase is a tetragonal phase, the content of oxygen is 4000 ppm or less, the content of carbon In the production of an alloy powder for rare earth magnets having a Ca content of 600 ppm or less and a Ca content of 1000 ppm or less, at least one of the rare earth oxides and a particle size of 150 μm.
A mixed powder in which the above composition is blended with an iron powder of 150 μm or less, at least one of pure boron powder, ferroboron powder, and boron oxide, or an alloy powder or mixed oxide of the above constituent elements, and additional element powder with a particle size of 150 μm or less. In addition, metal Ca is added in an amount of 1.5 to 3.5 times the stoichiometrically required amount of oxygen contained in the raw material powder such as the rare earth oxide.
and 1wt% to 15wt% of rare earth oxide CaCl_2
are mixed and heated to 900°C to 1200°C in an inert gas atmosphere to perform reductive diffusion, and the resulting reaction product is poured into ion-exchanged water cooled to 15°C or less to form a slurry. A method for producing alloy powder for rare earth magnets, which comprises treating slurry with ion-exchanged water cooled to 15° C. or lower.