JPS61270314A - Production of rare earth alloy powder - Google Patents

Abstract

PURPOSE:To obtain alloy powder for a magnet having excellent magnetic characteristics by mixing Ca for reducing to a raw material consisting of a heavy rare earth, rare earth, B, Co and Fe, heating the mixture to reduce and diffuse the same then treating the mixture with water. CONSTITUTION:The powder raw material consisting, by atomic %, of 12.5-20% R (where R1; 0.05-5%), 4-20% B, <=35% Co and 45-82% Fe is prepd. R1 is >=1 kinds among Gd, Tb, Dy, Ho, Er, Tm and Yb which are the rare earths and R is R1+R2. R2 is the rare earth element contg. >=80% Nd+Pr and the balance Y except R1. Such powder is mixed with the metallic Ca, etc. at 1.2-3.5 times the stoichiometrically required content and CaCl2 at 1-15wt% of the rare earth (oxide) as the reducing agent. The mixture is reduced and diffused at 950-1,200 deg.C in an inert atmosphere. The resultant product is brought into contact with water to form a slurry. The slurry is further treated with water and the alloy powder of which the main phase is a tetragonal crystal is obtd. The rare earth alloy powder contains <=10,000ppm O, <=1,000ppm C and <=2,000ppm Ca.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing rare earth alloy powder used in producing FeCoBR-based high performance rare earth magnets.

[Conventional technology]

FeBR magnets are attracting attention as new high-performance permanent magnets using rare earth elements (R) such as Nd and Pr, and as disclosed in Japanese Patent Application Laid-Open No. 1983-46008 filed by the present applicant. It has characteristics comparable to the conventional high-performance magnet SmCo, and has the advantage that Sm, which is expensive and rare in terms of resources, is not essential as R. In particular, Nd has conventionally been considered to be a component with no utility value, and the ability to use Nd as a main component is extremely useful industrially.

However, the Curie temperature of this FeBR magnet alloy is about 30
Since it is relatively low at around 0°C, it tends to lack stability when used at temperatures above room temperature. It has been attempted to improve the stability against temperature by increasing the Curie temperature by using a FeCoBR magnet alloy in which a part of Fe is replaced with CO (Japanese Patent Laid-Open No. 59-64733).

[Problems to be solved by the present invention]

The basic purpose of the present invention is to provide this FeCoBR magnet with even higher magnetic properties and to enable it to be manufactured at a lower cost.

In more detail, the present invention relates to the R, -R2-Fe-Co-B system (herein, R+ is Gd, Tb, DV, Ho, Er, Tm,
One or more types of Yb (7), R2 has a total of Nd and Pr of 8
0% or more, the remainder containing at least one rare earth element containing Y other than R1), which is used in high-performance rare earth magnets. The aim is to provide powder.

Recently, Nd-Fe-B or Nd-Fe-Co magnets have been attracting attention as an alternative to samarium-cobalt rare earth magnets.
- In B-based rare earth magnets.

Light rare earth components such as Nd and Pr are replaced with Gd and Tb.

By using at least one heavy rare earth element such as Dy, Ho, and Er at a concentration of less than 5w, (BH) max.
= R that has a high energy product of 20 MGOe or more, has a coercive force (iHc) dramatically improved to 10 koe or more, and can be used even in a temperature environment of 100 to 150°C above room temperature.

-R2-Fe-Co-B rare earth magnet (here R1 is G
d, Tb, Dy, Ho, and one or more of the heavy rare earth elements of Er, R2 is Nd and Pr in total of 80% or more, and the rest is R.
At least one rare earth element containing Y other than 1)
has been proposed (Japanese Patent Application No. 58-141850).

The starting materials for manufacturing R+ R2F e -C: o -B rare earth magnets are rare earth metals with a purity of 99.5% or more made by electrolytic method or thermal reduction method, and electrolytic iron with a purity of 99.9% or more. Conventionally, expensive metal ingots with few impurities, such as electrolytic cobalt and poron, are often used. Therefore, all raw materials are of high quality with few impurities and have been refined from ores in advance, and the price of magnets manufactured using these raw materials is extremely high. In particular, the production of rare earth metals requires advanced separation and purification technology, and the production efficiency is low, so their prices are generally extremely high.

Therefore, R, -R2-Fe-Co-B permanent magnets are iH
Although it has a high c and high performance and is very useful as a practical permanent magnet material, the price of the magnet is quite high.

The specific object of the present invention is to solve the above-mentioned problems and provide a heavy rare earth alloy powder for magnet materials containing rare earth elements at low cost and of excellent quality on a mass production scale. That is, the present invention provides (BH)max by obtaining R, -R2-Fe-Co-B alloy powder by a specific manufacturing method.
To make it possible to provide at a low cost an R, -R2-Fe-Co-B-based rare earth magnet that can be used stably at high temperatures above room temperature while maintaining magnetic properties of 20 MGOe or more and iHc of 10 kOe or more. It is something.

C Solution Means and Effects According to the Present Invention] That is, in the present invention, the produced alloy contains: R: 12.5 to 20 atomic % (R of R: 0.05 to 5 atomic %), B: 4 to 20 atomic %, Co: 35 atomic % or less (excluding Co 0%), and Fe + 45 to 82 atomic % (here, R1 is a heavy rare earth element Gd, Tb, l) y, Ho
, Er, Tm, Yb, R2 is Nd and P
The total of r is 80% or more, and the remainder is at least one rare earth element containing Y other than R1, and R=R1+R2 (atomic%
) with at least one of the rare earth oxides and at least one of iron powder, cobalt powder, pure boron powder, ferroboron powder, and boron oxide powder, or The raw material mixed powder made by blending the alloy powder or mixed oxide with the above-mentioned constituent elements is added to the stoichiometrically necessary amount of oxygen required for the orphan relative to the amount of oxygen contained in the raw material powder such as the rare earth oxide. 2 to 3.5 times (weight ratio)
of calcium metal and/or calcium hydride and 1 to 15% by weight of calcium chloride of a rare earth oxide,
Reduction Φ diffusion is carried out at a temperature of 950-1200°C in an argon atmosphere, the resulting reaction product is brought into contact with water to form a slurry, and the slurry is treated with water to form a main phase (specific phase is 80% (above) is a tetragonal alloy powder having the above composition, an oxygen content of 110,000 PP or less, a carbon content of 1QOO ppm or less, and a calcium content of 1
This is a method for producing rare earth alloy powder, characterized in that i is 2000 ppm or less.

By using R1-R2-Fe-Co-B alloy powder according to the production method of the present invention, (B H) max 20MG
An R, -R2-Fe-Co-B rare earth magnet that can be used stably at temperatures above room temperature while maintaining magnetic properties of Oe or more and iHc of 10 kOe or more at a low cost. It is.

This alloy powder is used in the preliminary stage of producing rare earth metals. Intermediate raw materials include inexpensive light rare earth oxides such as Nd2O3 and Pr60, heavy rare earth oxides such as Tb30d and DYzO3, Fe powder, cobalt powder, and pure boron. powder(
(crystalline or amorphous), using boron oxide such as Fe-B powder or B2O powder as a starting material, and using metallic calcium and/or calcium hydride as a reducing agent, to facilitate the disintegration of the reduction reaction product. Since the alloy powder for R + -R2-Fe-Co-B magnets is manufactured by a process using calcium chloride (CaCJ12) of When incorporating additive elements into a zero-based alloy powder that can be easily obtained on a large scale, metal powders, oxides (constituent elements (including mixed oxides with Ca), alloy powders (including alloys with constituent elements), or other compounds reducible by Ca. As alloys with constituent elements, V, Ti, Zr, Hf
There are also borides such as , Ta, and Nb.

By using the alloy powder of the present invention, it is possible to shorten the manufacturing process of magnets, and the low-cost R1-R2-Fe-C
It has become possible to provide o-B rare earth magnets, and the economic effect is very significant.

Here, if a mixed powder of rare earth oxide and metal powder such as Fe powder, Ca powder, or Fe-B powder is used as a starting material and is subjected to a reduction/diffusion reaction with metal Ca, at the reduction reaction temperature, C
The molten rare earth metal reduced in step a immediately alloys with Fe powder, CO powder, and Fe-B powder very easily and homogeneously to form R, -R2-Fe-Co-B from the rare earth oxide.
The system alloy powder can be recovered with a high yield, and the RI and R2 rare earth oxide raw materials can be used effectively. Calcium hydride can also be used as a reducing agent instead of metallic Ca.

In addition, the content of B (boron) component in the raw material powder is R, -B2
It is effective in lowering the reduction/diffusion reaction temperature when producing -Fe-Go-8 alloy powder, and facilitates the reduction/diffusion reaction of this alloy powder.

Therefore, in order to obtain raw material alloy powder for R, -R2-Fe-Co-B magnets in large quantities on an industrial scale from inexpensive rare earth oxides, a large quantity of aggregation is required to produce inexpensive alloy powders of Fe and B. The R1-12-Fe-Go-8 alloy powder of the present invention having a specific composition range was invented based on the fact that it is most effective to do so and can be used as it is for magnet production.

[Preferred mode of implementation]

The rare earth-containing alloy powder according to the present invention is manufactured by the following steps.

Ndm compound (Nd203) and Pr oxide (Pr60+)
A small amount of light rare earth (R2) oxides such as IM and Tb
At least one heavy rare earth (R1) oxide such as oxide (Tb407) or DV oxide (DYzO3), iron (F
e) powder, Kobal (Co) powder, and pure boron powder.

Ferroboron (Fe-B) powder, phoron dioxide (B20:
l) R: 12.5 to 20 M% (R1: 0.05 of R)
~5 atom%).

B: 4 to 20 atomic%.

Co: 35 atomic % or less (excluding 0% Co) Fe: 45 to 82 atomic % (here, R is a heavy rare earth element Gd, Tb, Dy, Ho,
One or more of Er, Tm, Yb, R2 is Nd and P
The total of r is 80% or more, and the remainder is at least one rare earth element containing Y other than R1, and R=R, +R2 (atomic%
), and if necessary, add additional elements in the form of metals, oxides, alloys, or other compounds (powders of) to obtain a raw material mixed powder. The amount of raw material oxide is determined by considering the yield for the composition of the produced alloy (
In the case of rare earth elements, typically 1.1 times), metallic Ca and/or calcium hydride are further used as reducing agents for rare earth oxides, and CaCuz powder is added to accelerate the disintegration of the reaction product after reduction. . The required amount of Ca is 1.2 to 3.5 times (weight ratio) (preferably 1.2 to 3.5 times) the stoichiometric amount required to reduce oxygen contained in the raw material mixed powder.
5 to 2.5 times, more preferably 1.6 to 2.0 times), and the amount of CaC2 is 1 to 15% (
weight ratio), (preferably 2 to 10%, more preferably 3 to 6%).

A mixed powder consisting of the above raw material powders such as rare earth oxide powder, Fe powder, Ca powder, ferroboron powder, Ca reducing agent, etc. was heated to 95% in an inert gas atmosphere such as argon.
The reduction/diffusion treatment is carried out at a temperature range of 0 to 1200°C (preferably 950°C to 1100°C) for about 1 to 5 hours, and then cooled to room temperature to obtain a reduction reaction product. Does the container used for this reduction and diffusion treatment react with rare earth elements?

Alternatively, materials with extremely low reactivity such as stainless steel must be used.The inner wall of the reaction vessel must be made of MgO, C
Lining with aO or the like is effective. When this is pulverized to a suitable particle size of 1, for example, 8 me s h (2.4 mm) or less and brought into contact with water, calcium oxide (Cab), CaO・2CaCJ12 and excess calcium in the reaction product are converted to calcium hydroxide (Ca (OH) 2 ), etc., and the reaction product collapses into a mixed slurry with water. This slurry is treated to sufficiently remove the Ca content using water to obtain the rare earth-containing alloy powder of the present invention having a powder particle size of approximately 10 to 500 inches. If it is less than 1'Opm, the amount of oxygen in the alloy will increase and excellent magnetic properties cannot be obtained.If it is more than 500 gm, the diffusion reaction during reduction is often insufficient, and α-Fe phase etc. will appear in the magnet. i to do
Hc decreases and the squareness of the demagnetization curve deteriorates.

The preferred particle size of the present invention is from 20 to 300 lm in terms of workability in the subsequent magnetization process and magnetic properties.

Furthermore, the reduction reaction product was made into 8 mesh (2.4 mm)
If it is poured into water without being crushed or as a mesh larger than 8 mesh, the above-mentioned collapse reaction will be extremely slow, making it unsuitable for industrial production, and the heat of the collapse reaction will accumulate inside the reduction product, resulting in a high temperature. The amount of oxygen in the rare earth alloy powder exceeds 110,000 pp, making it difficult to use it in the subsequent magnetization process. In addition, 35 mesh (0
, 5 mm), the reaction in water will be too intense and combustion will occur. If the wood used here is ion-exchanged water or distilled water, the amount of oxygen contained in this alloy powder will be reduced, which is preferable from the viewpoint of the yield and magnetic properties of the magnetization process described later. When a magnet is polished, the aforementioned compositional alloys and their abrasive powders are produced, and these abrasive powders can also be used as starting materials for the reduction reaction.

The alloy powder for magnet materials obtained as described above has R: 12.5 to 20 at% (R: 0.05 to 5 at% of R), B: 4 to 20 at%, Co: 35 atomic% or less (excluding Co 0%), Fe: 45 to 82 atomic% (here, R1 is a heavy rare earth element CD, Tb, Dy, HO2
One or more types of Er, R2 has a total of Nd and Pr of 80
% or more and the remainder is at least one rare earth element containing Y other than R1 (R = R1 + R2 (atomic %)), the main phase (80% or more of the specific phase) is tetragonal, and contains oxygen. Amount 110000pp or less, carbon content i1000pp
m or less, and the calcium content is 312,000 ppm or less.

The rare earth alloy powder in the present invention is R, -R2-Fe-
When the Co-B magnet alloy is manufactured, it is finely pulverized as it is, and then press-formed and then sintered (with no compressive force applied or applied).
→It can be made into a permanent magnet by a powder metallurgy method called aging treatment. This fine pulverization is preferably carried out to 1 to 20 gm, more preferably 2 to 10 gm, using an attritor, a ball mill, a jet mill, or the like. In addition, in order to manufacture anisotropic magnets, particles can be oriented and shaped in a magnetic field6.
If the earth alloy powder of the present invention is used, the manufacturing process of magnets such as alloy melting → casting → coarse pulverization will be easier than when manufacturing permanent magnets using raw material lumps such as rare earth metal lumps, iron, and poron. It has the advantage that the cost of the finished magnet is low because it can be omitted and cheap starting materials such as rare earth oxides are used, and it is economical because practical water-immersed magnet materials can be easily produced on a mass production scale. It's also big.

The oxygen contained in the alloy powder of the present invention combines with the rare earth element that is most easily oxidized to form rare earth oxides, and when the oxygen content exceeds 110,000 pp, oxides (R
20wl), the oxygen content is undesirable because the magnetic properties, particularly the coercive force, become lower than 10 kOe.The oxygen content is preferably 6000 ppm or less, more preferably 4000 ppm or less.

If the carbon content exceeds 11,000 pp, it remains in the permanent magnet as a carbide (HO2, etc.) as in the case of oxygen, reduces the squareness of the demagnetization curve, and the coercive force becomes 10 koe or less.

The carbon content is preferably 600 ppm or less.

Furthermore, if the calcium content exceeds 2000 ppm, a large amount of highly reducing Ca vapor will be generated during the subsequent sintering process during which the alloy powder is magnetized, which will seriously contaminate the heat treatment furnace. In some cases, the furnace wall of the heat treatment furnace may be damaged, making stable industrial production impossible, and the carbon contained in the finished permanent magnet may be damaged.
The amount of a also increases, causing deterioration of magnetic properties. - The amount of Ca in the produced alloy is preferably 10αOppm or less.

If the amount of Ca as a reducing agent in the raw material in the present invention is more than 3.5 times the stoichiometrically required amount, a rapid chemical reaction will occur during the reduction/diffusion reaction, resulting in significant heat generation and strongly reducing C.
The reduction/diffusion containers are severely consumed by a, making industrially stable production impossible. In addition, the amount of residual Ca in the alloy powder produced by reduction increases, causing a large amount of Ca vapor to be generated during the subsequent heat treatment for magnetization, causing wear and tear on the heat treatment furnace body, and increasing the amount of Ca in the finished magnet. This causes deterioration of magnetic properties.

On the other hand, if the amount of Ca is less than 1.2 times, the reduction φ diffusion reaction is incomplete and a large amount of unreduced substances remains, making it impossible to obtain the rare earth alloy powder of the present invention.

If the amount of Cac12 exceeds 15% (wt%) of the rare earth oxide, when the reduced O-diffusion reactant is treated with water, C
1- (chloride ions) increases significantly and reacts with the generated rare earth alloy powder, and the oxygen content of the powder exceeds 110,000 pp, making it unusable as a raw material for R1-R2-Fe-Co-B magnets.

If the amount is less than 1% by weight, the reduction/diffusion reactant will not disintegrate even if placed in water, making it impossible to treat with water.

The reason for limiting the component range of the rare earth alloy powder of the present invention is as follows.

R (at least one rare earth element including Y) is an essential element for the new R1-R2-Fe-Co-B permanent magnet, and when it is less than -,12,5)X%, the present system As Fe precipitates in the alloy, the coercive force rapidly decreases, and when it exceeds 20 atomic %, the coercive force shows a large value of 1 okoe or more, but the residual magnetic flux density (Br) decreases and (BH) max.
If more than 20 MGOe is required, r will not be obtained.

Therefore, the rare earth element (R) is 12.5 at% to 20
jlX child% range.

The amount of R1 partially constitutes the above-mentioned R. Even if the amount of R1 is only 0.05 at% substitution, Hc increases, the squareness of the demagnetization curve is also roughly improved, and (BH) max increases. . Therefore, the lower limit of R1 amount is determined by the effect of iHc increase and (BH)
Considering the effect of increasing max, the content is set to 0.05 at.% or more. As the amount of R1 increases, iHc increases (
BH)wax peaks at 0.4 at% and decreases little by little, but for example, even with 3% substitution, (BH)max decreases to 3.
Indicates 0MGOe or more.

For applications where stability is particularly required, it is more advantageous to have a higher iHc, that is, to contain more R1. But R,
The elements that make up the rare earth ore are only contained in small amounts in rare earth ores and are very expensive.

Therefore, the upper limit is set at 5 at.%. In addition, as R1, Dy and 'rb are particularly preferable.The remaining R2 elements are the main constituent elements of the permanent magnet according to the method of the present invention, and are mainly composed of Nd and/or Pr, and the total is 80 atomic % or more. The remainder is one or more rare earth elements containing Y other than R1,
Outside this range (BH) max 20MGOe or more, iH
c It becomes impossible to obtain magnetic properties of 10 koe or more. Note that as for R2, it is desirable that Sm and La be as small as possible.

When the amount of B is 4 atomic % or less, iHc becomes 10 koe or less. Also, an increase in the amount of B increases <IHc, which is the same as an increase in the amount of R, but Br decreases <, (BH)max
In order to achieve 20 MGOe or more, B is required to be 20% or less. Therefore.

The amount of B is in the range of 4 atomic % to 20 atomic %.

In the present invention, the Curie temperature of the tosa magnet in which part of the Fe in the FeBR system is replaced with Co is C.

It gradually increases as the amount of substitution increases. Even a small amount of Co substitution (for example, 0.1%) is effective in increasing the Curie point, and depending on the amount of Co substitution, an alloy with an arbitrary Curie point of about 310 to about 640°C can be obtained (Japanese Patent Laid-Open No. 59-647
33), therefore, the lower limit of the amount of Co is not particularly limited, but it is preferably 0.1 atomic % or more.
When the Co content exceeds 35%, (BH)max decreases and becomes lower than 20MGOe. In the FeBR system, the temperature coefficient of Br from room temperature to 150°C is approximately 0.13%/
℃, but by containing more than 5% of Co, Br
The temperature coefficient of is approximately 0.1%/°C or less. In addition, Co
At 25 atomic % or less, it is possible to increase the Curie point without substantially deteriorating other properties, and about 20 atomic % before @ (17
~23 at%) also increases iHc. The amount of Co is 5~
Most preferably, it is 6 atom %.

In addition, CO concaveness improves the oxidation resistance of the magnetic alloy, and has a remarkable effect on improving the yield of reduction reaction products during the production process when they disintegrate, and improving the brewing resistance of fine powder.

Fe is an essential element for new R, -R2-Fe-Co-B permanent magnets, but if it is less than 45 at%, the residual magnetic flux density (Br) will decrease, and if it exceeds 82 at%, it will have a high coercive force. is not obtained, so the Feel is 45 atomic% to B2g%
limited to. The amount of Fe is more preferably 45 to 80 W%. Further, the total amount of Fe and Co is preferably 60 atomic % or more, and most preferably the Fe amount is 60 atomic % or more.

Further, the alloy powder according to the present invention is R, B.

In addition to C01Fe, the inclusion of unavoidable impurities in industrial production is acceptable.For example, 2 at% or less of P, 2 at% or less of S, 2 at% or less of Cu, the total amount of which is at most 2 at%. However, it still shows practical magnetic properties, and it is possible to improve the manufacturability and lower the cost of magnetic alloys. However, since these elements generally lower Br, it is better to have less of them (for example, 0.5
Br
The range shall be 9kG or more. Furthermore, the R-Fe-Co
By containing at least one of the following additional elements in place of Fe in the -B alloy, it is possible to increase the coercive force of the permanent magnet alloy: 5.0 at% or less of A, 3. 0f atomic % or less c7) Ti, 5.5 atomic % or less V, 6.0 atomic % or less Ni, 4.5 atomic % or less Cr, 5.0 atomic % or less (1') M n, 5. Bf of 0 atomic % or less, Nb of 9.0 atomic % or less, Ta of 7.0 atomic % or less, M 0 of 5.2 atomic %.

W of 5.0 atomic % or less, Sb of 1.0 atomic % or less, 3, 5 [Ge below %, Sn of 1.5 atomic % or less, Zr of 3.3 atomic % or less, 3.3 atomic % or less of Hf, and Si of 5.0 atomic % or less.

These additive elements are added to the starting raw material mixed powder, such as metal powder,
It can be added as an oxide, an alloy powder or mixed oxide with alloy a-component elements, or a compound reducible with Ca.

The above-mentioned additive elements generally have the effect of increasing iHc and increasing the squareness of the demagnetization curve, but on the other hand, as their content increases,
Br is decreasing.

(BH)max Br to have 20MGOs or more
9 kG or more is required, and therefore, the upper limit of each content is determined to be below the above-mentioned value, except in the case of BE, Ni, and Mn. The upper limit of Bi is determined from the viewpoint of its high vapor pressure, and the upper limit of Ni and Mn is determined from the viewpoint of iHc. Further, Si has the effect of increasing the Curie temperature. If two or more elements are contained, the upper limit of the total content shall be less than or equal to the maximum value of the respective upper limits of the elements. For example, if Ti, Ni, and Nb are contained, the upper limit of the total content shall be 0. , 9% or less of Nb. Especially among the contained elements, V, Nb, Ta, Mo
, W, Cr, and A are preferable.The content of the added element is preferably small, and generally 3 atomic % or less is effective (0.1 to 3 TX element % in the case of An, especially 0.2 to 2 atomic %) .

The main crystal phase (the specific phase is 80% by volume or more, preferably 90% by volume or more, more preferably 95% by volume or more) is tetragonal, which is fine enough to exhibit high magnetic properties as a magnet. is essential to obtain a uniform alloy powder. This magnetic phase is composed of FeCoBR tetragonal compound crystals,
The grain boundaries are surrounded by a non-magnetic phase. The non-magnetic phase mainly consists of an R-rich phase (R metal). When there is a large amount of B, a B-rich phase may also be partially present. The presence of the non-magnetic layer grain boundary region is considered to contribute to high properties and constitutes an important structural feature of the alloy of the present invention.

Even a small amount of non-magnetic layer is effective; for example, 1vo
1% or more is a sufficient amount. It is a tetragonal crystal, and its central composition is thought to be R2(Fe,Co)I aB. This alloy powder is generally crystalline, and typically the grain size of the crystals constituting the powder particles is about 11 mm. The amount of tetragonal phase, which is larger than m (however, only when the powder particle size is larger than this), can be measured using the intensity of X-ray diffraction, an X-ray microanalyzer, or the like. Furthermore, the sintered permanent magnet using this alloy powder is of delivery quality, and the average crystal grain size of the R(Fe, Co)B tetragonal phase is 1 to 40 ILm (more preferably 3 to 204 m). Desirable for its excellent permanent magnetic properties.

Hereinafter, aspects and effects of the present invention will be explained according to examples. However, the present invention is not necessarily limited to the description of the examples.

〔Example〕

Example l Nd2O, powder: 54.8gr, DY203 powder: 5.6 gr.

Ferroboron powder (19.5wt% B-Fe alloy powder)
: 6.5gr, Fe powder: 42.6gr.

Ca powder: 18.6gr.

Metal Ca: 53.5gr (2.5 times the stoichiometric ratio).

CaCJ12: Using a total of 184.2 gr of raw material powder of 2.6 gr (4.3 wt% of rare earth oxide raw material), 30.0% Nd
-3,8%D7 -47.7%Fe-17,5%Co-1
, 12%B (wt%) (14,0%Nd-1,5%Dy
-57,5%Fe-20%Co-7,0%B CM child%
)] Mixing was performed using a V-type mixer, aiming at the composition alloy.

Next, the compressed body of this mixed raw material was filled into a stainless steel container, placed in a Matsufuru furnace, and the temperature inside the inner chamber was raised in an argon gas stream. After maintaining the temperature at 1150"0x3hr, the furnace was cooled to the room temperature.The obtained reduction reaction product was heated to 8 m
Calcium oxide (Cab) and C
aO・2CaCu2. The unreacted residual calcium was converted into calcium hydroxide (Ca (OH) 2 ) to disintegrate the reaction product into a slurry. After stirring for 1 hour, 30
The calcium hydroxide suspension was left to stand for a minute, water was poured again, and the process of leaving the jar still in a stirring pot and removing the suspension was repeated several times. Nd-Dy-Fe- separated and collected in this way
The Co-B alloy powder is dried in vacuum, and the 20~
84 gr of rare earth alloy powder for magnet materials with a capacity of 300 pLm was obtained.

The results of component analysis are as follows: Nd: 30.2vrL%.

Dy: 3.3wt%.

Fe: 48.2wt%, Co: 15.8wt%, B: 1-1 wt%.

Ca: 800ppm.

The desired alloy powders of 02: 4100 ppm and C: 670 ppm were obtained. According to the measurement of the X-ray diffraction pattern, it was an alloy powder containing 95% or more of the main phase of a tetragonal intermetallic compound having the following.

This powder was finely pulverized to a powder having an average particle size of 2.50 μm and compressed into a compact in a magnetic field of 10 kOe at a pressure of 1.5 t/Crn'(7). Thereafter, sintering was performed at 1120° C. for 2 hours (1) in an Ar flow and aging treatment was performed at 600° C. for 1 hour to prepare a permanent magnet sample.

Br=11.5kG.

1Hc=16.3koe.

(BH)max=31.7MGOe The excellent magnetic properties have been changed.

Also, the temperature coefficient of Br in this alloy magnet is α=0.075%
/℃.

Example 2 Nd203 powder +47. Ogr, Dy20: l: 1.6gr, 7, b poey powder (19, Owt%B-Fe alloy powder): 6.4gr.

Raw materials: Fe powder: 61.2gr, Ca powder: 4.4gr, metallic Ca2 43.3gr (2.5 times the stoichiometric ratio), CaCl2: 2.5gr (5.0wt% of rare earth oxide raw material) Using a total of 166.4 gr of powder, 30.4% Nd
-1,2%Oy-62,7%Fa-4.5%Go-1,
2%B (wt%) (13,8%Nd-〇, 5%DY-7
3.5%Fe-5%Co-7,2%B (atomic %)] was heated at 1070°C in the same manner as in Example 1, aiming at the composition alloy.
After the reduction treatment for several hours, 79g of the 20-500 pm rare earth alloy powder for magnet materials of the present invention was obtained.

The results of component analysis are as follows. Nd: 29.5wt%, Dy: 1.1wt%, Fe: 61.3wt%, Co: 4.1wt%, B: 1.1 wL%.

Ca: 490ppm.

Desired alloy powders containing 02: 3300 ppm and C: 480 ppm were obtained. According to the measurement of the X-ray diffraction pattern, it was an alloy powder containing 93% or more of the main phase of a tetragonal intermetallic compound having a=8.79A and c=12.18A.

A permanent magnet sample was prepared in the same manner as in Example 1.

Br=12.5kG, tHc=12.1koe, (BH)maX=37.4MGO Excellent magnetic properties were obtained.

The temperature coefficient of Br in this alloy magnet is α=0, 09%/℃
Met.

Example 3 Nd20v powder: 36.3gr, CeO2 powder: 9.2 gr.

Dy2O3 powder: 3.1gr, Gd20ff powder: 3. Ogr, Fe powder: 49.9gr, Ca powder: 8. Ogr.

Fluoporon powder (19.0wt% B-Fe alloy powder): 9
．． Using a total of 192.2 gr of raw material powder of Ogr, metallic Ca + 88.5 gr (3.2 times the stoichiometric ratio), Ca (, l,: 5.2 gr (10 wt% of rare earth oxide raw material)), 24.4% Nd
-4,3%Ce-2,5%DY-2,4%Gd-55,
7%Fe-9,0%Co-1,7%B (wt%) [11
%Nd-2%Ce-1%DY-1%Gd-75%Fe-
10% B (atomic %)] Aiming for a composition alloy, 87 gr of powder of 30 to 500 pm was obtained in the same manner as in Example 1.

The results of component analysis are as follows: Nd: 24.1 wt%, Ce: 4.0 wt%, Dy: 2.3 wt%, Gd: 2.2 wt%, Fe: 55.9 wt%, Co: 8.8 wt%, A desired alloy powder containing B: 1.6 wt%, Ca: 11100 ppm, 02: 5500 ppm, and C: 600 ppm was obtained. According to the measurement of the X-ray diffraction pattern, it was an alloy powder containing 87% or more of the main phase of a tetragonal intermetallic compound having the following.

The obtained powder was finely pulverized to a powder having an average particle size of 3.5 pm and compressed into a compact in a magnetic field of LOkOe at a pressure of 1.5 t/crn'. After that, sintering in an Ar flow at 1100°C for 2 hours and aging treatment at 600°C for 1 hour were performed to prepare a permanent magnet sample.

Br=10.7kG, 1Hc=lo, 4koe, (BH)max=25.2MGOe The excellent magnetic properties have been changed.

The temperature coefficient of Br in this magnet was α=o, oaa%/°C.

Example 4 Nd203 powder: 45. Ogr, Dy2O3 powder:5. Ogr, Fe powder: 42.3gr.

Ca powder: 18.9gr, Fe-B powder (19, Owt% B-Fe alloy powder) near,
4 gr.

AJL203 (alumina) powder: 1. Ogr.

Using a total of 170.6 gr of raw material powder of metal Ca: 49.5 gr (2.8 times the stoichiometric ratio) and CaCu2: 3.5 gr (7 wt% of the oxide raw material), 29.6% Nd
-3,7Dy-56,02%Fe-8,96%Co-1
,3%B-0,4%kl(wt%)(13,5%Nd-
1,5%DV-66,0%Fe-10%C0-8%B-
1.0% Hachimon (atomic %)] Example 1 aiming at composition alloy
In the same manner as above, perform reduction treatment at 30°C for 3 hours.
88 gr of alloy powder of ~500 #Lm was obtained.

The results of component analysis are as follows. Nd: 29.6wt%, Dy: 3.7wt%.

Fe: 55.9wt%.

Co: 8.9wt%, B: 1.2wt%.

AjL: 0.4wt%, Ca near 50ppm, 02: 3100ppm.

C: 670 ppm ''' of the desired alloy powder was obtained. Measurement of the X-ray diffraction pattern revealed that the alloy powder had 92% or more of tetragonal intermetallic compounds as the main phase.

A permanent magnet sample was prepared in the same manner as in Example 2.

Br=11.5kG, tHc=17.5koe, (BH)max=30.8MGOe The excellent magnetic properties have been changed.

The temperature coefficient of Dr of this magnet was α=0.085%/°C.

Example 5 Nd20. Powder: 44.1gr, Dy2O3 powder: 4.5gr.

Fe powder: 49.9gr, Co powder: 8. Ogr, 7z O poron powder (19, Owt% B-Fe alloy powder) Nia, Ogr, Ferron niobium powder (67,3wt% Nb-Fe alloy powder): 2.2gr, Metal Ca: 43. Using a total of 158.2 gr of raw material powder of Ogr (2.5 times the stoichiometric ratio), CaCjL2: 5.8 gr (12 wt% of rare earth oxide raw material), and 27.4% Nd.
-3,7%0y-52,7%Fe-13,5%Co-1
,3%B-1,4%Nb(wL%)(12,5%Nd-
1,5%ny-62.0%Fe-15,0%Co-8%
B-1%Nb (atomic %)] Example 3 aiming at composition alloy
In the same manner as above, 88 gr of powder of 20-500 pm was obtained.

The results of component analysis are as follows. Nd: 27.2wt%, Dy: 3.7wt%.

Fe: 51.7wt%.

Co: 13.9wt%.

B: 1.2wt%, Nb: 1.4wt%, Ca near 00ppm, 0224800ppm.

C: 560 ppm of the desired alloy powder was changed. The measurement of the X-ray diffraction pattern revealed that the alloy powder contained 95% or more of the main phase of a tetragonal intermetallic compound having a=8.78A and c=12.17A.

A permanent magnet sample was prepared in the same manner as in Example 3.

Br=11.5kG, 1Hc=14.5koe, (BH)max=30.5MGOe Excellent magnetic properties were obtained.

〔effect〕

As detailed, according to the present invention, R, -R2-Fe-Co
- An alloy powder with a similar composition for producing B-based magnets can be obtained at low cost using rare earth oxide and boron oxide raw materials as starting materials, and by using it, R1-R2- has excellent temperature characteristics and corrosion resistance. Fe-Go-B permanent magnets can be obtained, and the manufacturing steps of rare earth metal isolation and refining, melting of the alloy, cooling (usually casting), and pulverization of the specified alloy powder can be omitted from the magnet manufacturing process. Shortening is realized. This shortening of the process is extremely useful in avoiding the contamination of undesirable components or impurities (such as oxygen) during the process. In particular, it is difficult to prevent # elements from being mixed into the process from melting to pulverization because it requires complicated process control, and this is a cause of increased manufacturing costs.

Furthermore, it is not necessarily necessary to use separated rare earth oxides, but it is possible to use an oxide mixture close to the target composition or a partially deficient rare earth oxide as a starting material. Even in the oxide separation process itself, it is possible to shorten the process and reduce costs.

Furthermore, the alloy of the present invention is highly effective in that it can be obtained directly by a direct reduction method as an alloy whose main phase is a tetragonal magnetic phase, which is essential for magnetic properties, and it is also a great advantage that it can be obtained in powder form. be. A method for obtaining rare earth magnets from alloy powder obtained by reducing rare earth oxides is known for Sm-cobalt magnets. However, Sm/cobalt magnets are 1150~
Since a high reduction temperature of 1300° C. is required, grain growth occurs, it is difficult to obtain a powder with uniform particle size during mausoleum destruction, and the container used during reduction is significantly damaged due to the reaction.

Taking all the above into account, it is recognized that the effects of the present invention are those of author J11.

Applicant: Sumitomo Special Metals Co., Ltd. Agent Patent Attorney Kato Hado (1 other person)

Claims (1)

[Scope of Claims] 1) The produced alloy contains R: 12.5 to 20 atomic % (R_1: 0.05 to 5 atomic % of R), B: 4 to 20 atomic %, Co: 35 atomic % or less ( However, Co0% is excluded), and Fe: 45 to 82 atomic% (here, R_1 is a heavy rare earth element Gd, Tb, Dy, Ho
, Er, Tm, and Yb, R_2 is at least one rare earth element containing Nd and/or Pr at 80 atomic % or more, and the remainder is Y other than R_1 R = R_1+
R_2 (at. The above, or the raw material mixed powder made by blending the alloy powder or mixed oxide of the above constituent elements, has a stoichiometric amount required for reduction with respect to the amount of oxygen contained in the raw material powder such as the rare earth oxide. 1.2 to 3.5 times (weight ratio) metallic calcium and/or calcium hydride and 1 to 15% by weight of calcium chloride of rare earth oxide are mixed and heated at 950 to 1200°C in an inert atmosphere.
Reduction and diffusion are carried out at a temperature of Collected, having the above composition and oxygen content of 10,000p
pm or less, carbon content of 1000 ppm or less, and calcium content of 2000 ppm or less. 2) Partially replacing the Fe, in the raw material mixed powder, 5.0 atomic % or less Al, 3.0 atomic % or less Ti, 5.5 atomic % or less V, 6.0 atomic % or less Ni, 4.5 atom% or less Cr, 5.0 atom% or less Mn, 5.0 atom% or less Bi, 9.0 atom% or less Nb, 7.0 atom% or less Ta, 5.2 Mo at % or less, W at 5.0 atomic % or less, Sb at 1.0 atomic % or less, Ge at 3.5 atomic % or less, Sn at 1.5 atomic % or less, Zr at 3.3 atomic % or less , characterized in that at least one of Hf of 3.3 atomic % or less and Si of 5.0 atomic % or less is added as a metal powder, an oxide, or an alloy powder or mixed oxide with a constituent element. The manufacturing method according to claim 1.