JPH0791563B2 - Rare earth containing alloy powder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an R-Fe-B alloy powder as a raw material for a rare earth R-iron Fe-boron B-based permanent magnet. It is intended to provide R ₁ -R ₂ -Fe-B based alloy powder at a low cost on an industrial mass production scale.

[Conventional technology]

Recently, samarium-cobalt rare earth magnets have replaced R-Fe
-B rare earth magnets have been attracting attention (Japanese Patent Laid-Open No. 59-46008).
Etc.).

[Problems to be solved by the invention]

The present applicant has further sought to improve N-Fe-B magnets by using Nd and Pr.
By substituting 5 atomic% or less of at least one heavy rare earth element of Gd, Tb, Dy, Ho, Er, Tm, and Yb for light rare earth components such as (BH) max = 20 MGOe or more, a high energy product is obtained. As it is, the coercive force (iHc) is dramatically improved to 10 kOe or more, and the R ₁ -R ₂ -Fe-B system rare earth magnet (here, R ₁ Is Gd, Tb, D
One or more of the heavy rare earth elements y, Ho, Er, Tm, Yb, R ₂ is Nd
And the total of Pr are 80% or more, and the rest is at least one rare earth element containing Y other than R ₁ ). (Japanese Patent Application No. 58-140590) The starting material for producing this R ₁ -R ₂ -Fe-B system rare earth magnet is a rare earth metal having a purity of 99.5% or more and a purity of 99.9% or more made by an electrolytic method or a thermal reduction method. An expensive metal block with few impurities such as electrolytic iron and boron is used. Therefore, all of the raw materials are high-quality ones that have been purified from ore in advance and have few impurities, and the price of the product magnet using these raw materials becomes very expensive. In particular, the production of rare earth metal raw materials requires sophisticated classification and refining technology, and its production efficiency is poor, so its price is extremely high.

Therefore R ₁ -R is ₂ -Fe-B based permanent magnet having a high performance is iHc, although it is very effective as a practical permanent magnet material,
The price of the magnet will be considerably high.

The present invention solves the above-mentioned problems and is a rare earth element-containing R for a magnet material which contains a rare earth element and is inexpensive and excellent in quality.
The object is to provide (R ₁ -R ₂ ) -Fe-B based alloy powder at a low cost on an industrial mass production scale.

[Means for Solving the Invention and Effects]

That is, in the first aspect of the present invention, a calcium reducing powder having the following composition containing rare earth R, B, and Fe as main components, containing a trace amount of calcium used as a reducing agent for a raw material containing a compound of rare earth R. there, R: 12.5 to 20 atomic%, R _1: 0.05~5 atomic%, B: 4 to 20 atomic%, Fe: 60 to 83.5
Atomic%, (where R ₁ is a heavy rare earth element Gd, Tb, Dy, Ho, E
One or more of r, Tm and Yb, and R ₂ is 80 or more of one or more of Nd and Pr.
%, With the balance being at least one rare earth element other than R ₁ and Y, R = R ₁ + R ₂ (atomic%)), oxygen content 10,000 ppm or less, carbon content 1000 pm or less, and calcium A rare earth-containing alloy powder having a content of 2000 ppm or less and a main phase (a specific phase of 80 vol% or more) is tetragonal.

In a second aspect, a calcium-reducing powder having the following composition, which contains a small amount of calcium used as a reducing agent for a raw material containing a compound of rare earth R, and which contains rare earth R, B, and Fe as main components, wherein R: 12.5 to 20 atomic%, R ₁ : 0.05 to 5 atomic%, B: 4 to 20 atomic%, Fe: 60 to 83.5 atomic%, (where R ₁ is a heavy rare earth element Gd, Tb, Dy, Ho, Er, One or more of Tm and Yb, R ₂ is 80% or more of one or more of Nd and Pr, and the rest is at least one of rare earth elements including Y other than R ₁ , and R = R ₁ +
R ₂ (atomic%)), oxygen content 10000ppm or less, carbon content 1000pm or less, and calcium content 2000ppm or less, and the main phase (specific phase 80vol% or more) is a tetragonal crystal, Partially replacing the Fe, 5.0 atomic% or less of A
l, Ti less than 3.0 atomic%, V less than 5.5 atomic%, 6.0 atomic%
The following Ni, 4.5 atomic% or less Cr, 5.0 atomic% or less Mn, 5.
0 atomic% or less Bi, 9.0 atomic% or less Nb, 7.0 atomic% or less Ta, 5.2 atomic% or less Mo, 5.0 atomic% or less W, 1.0 atomic% or less Sb, 3.5 atomic% or less Ge, 1.5 S of atomic% or less
n, 3.3 at% or less Zr, 3.3 at% or less Hf, 5.0 at%
The rare earth-containing alloy powder is characterized in that at least one of the following Si is added and contained.

Note that, from both viewpoints, the above-mentioned calcium-reduced powder is a rare earth-containing powder containing rare earth R as one of the main components, which is obtained by adding calcium to a raw material containing a rare earth compound such as a rare earth oxide, and using this calcium as a reducing agent. It is an alloy powder. Calcium includes a simple substance or a compound.

By using the R ₁ -R ₂ -Fe-B alloy powder of the present invention (including the one containing a predetermined amount of a predetermined element in place of Fe, according to the second aspect of the present invention), (BH) max20MGOe. As described above, it can be stably used at room temperature or higher while maintaining the magnet characteristics of iHc10 kOe or higher.

Further, according to the present invention, the R ₁ -R ₂ -Fe-B rare earth magnet can be provided at low cost.

This alloy powder is an intermediate raw material before the production of rare earth metals. Light rare earth oxides such as Nd ₂ O ₃ and Pr ₆ Ol _{1 which} are cheap and heavy rare earth oxides such as Tb ₃ O ₄ and Dy ₂ O ₃ are inexpensive. And Fe powder and pure boron powder, Fe-B powder or B ₂ O ₃ powder as starting materials,
It is produced by a process using metal calcium as a reducing agent and calcium chloride (CaCl ₂ ) for facilitating the decomposition of the reduction reaction product. Therefore, alloy powders of excellent quality can be easily obtained on an industrial mass production scale at a lower cost than using various metal ingot raw materials. Further, by using this alloy powder, the manufacturing process of the magnet can be shortened, and the R ₁ -R ₂ -Fe-B system rare earth magnet having a low price can be provided, and its economical effect is very large. .

Here, when a mixed powder of rare earth oxide and metal powder such as Fe powder or Fe-B powder is used as a starting material and a reduction / diffusion reaction is performed with metallic Ca, the rare earth metal reduced by the molten Ca at the reaction temperature becomes Immediately and very easily and homogeneously alloy with Fe powder and Fe-B powder to convert R ₁ -R _2-
The Fe-B alloy powder is recovered with high yield, and the rare earth oxide raw material can be effectively used.

The content of B (boron) component in the raw material powder is R ₁ -R ₂ -Fe.
-Effective in lowering the reduction / diffusion reaction temperature when producing B alloy powder, and facilitating the reduction / diffusion reaction of the present alloy powder.

Therefore, in order to obtain a large amount of raw material alloy powder for R ₁ -R ₂ -Fe-B magnets from an inexpensive rare earth oxide on an industrial scale, an inexpensive alloy powder of Fe and B is produced in large quantities today. The present invention has led to the invention of the R ₁ -R ₂ -Fe-B alloy powder in the specific composition range of the present invention as being most effective.

[Preferred Embodiment]

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

At least one light rare earth (R ₂ ) oxide such as Nd oxide (Nd ₂ O ₃ ) or Pr oxide (Pr ₆ Ol ₁ ) and Tb oxide (Tb
₄ O ₇ ) or at least one heavy rare earth (R ₁ ) oxide such as Dy oxide (Dy ₂ O ₃ ), iron (Fe) powder and pure boron powder, ferroboron (Fe-B) powder, boron trioxide. At least one raw material powder of (B ₂ O ₃ ) powder is R: 12.5 to 20 atom% R ₁ : 0.05 to 5 atom% B: 4 to 20 atom% Fe: 60 to 83.5 atom% (where R ₁ Is one or more of heavy rare earth elements Gd, Tb, Dy, Ho, Er, Tm, Yb, and R ₂ is 80% or more of one or more of Nd and Pr, and the rest is
At least one rare earth element containing Y other than R ₁ is used, and R =
R ₁ + R ₂ (atomic%))
The raw material mixed powder. Further, metallic Ca and / or calcium hydride is used as a reducing agent for the rare earth oxide, and CaCl ₂ powder is added to accelerate the decomposition of the reaction product after reduction. The required amount of Ca is 1.2 to 3.5 times (weight ratio), preferably 1.5 to 2.5 times, and more preferably 1.6 times the stoichiometrically necessary amount required to reduce oxygen contained in the raw material mixed powder.
〜2.0 times, CaCl ₂ amount is 1 ~ 15% of rare earth oxide raw material
(Weight ratio), preferably 2-10%, more preferably 3
-6%.

The above-mentioned rare earth oxide powder, Fe powder, mixed powder consisting of each raw material powder such as ferroboron powder and Ca reducing agent in an argon inert gas atmosphere at 950 to 1200 ° C, more preferably at a temperature range of 950 to 1100 ° C. 1-5 hours reduction
Diffusion treatment is performed, and the product is subjected to reduction reactivity by cooling to room temperature. This is a suitable particle size, preferably 8mesh (2.4mm)
When crushed into the following and put into water, calcium oxide (CaO), CaO.2CaCl ₂ and excess calcium in the reaction product become calcium hydroxide (Ca (OH) ₂ ), etc., and the reaction product disintegrates into water. It becomes a mixed slurry with. With this slurry, the Ca content was sufficiently removed using water, and the powder particle size was approximately 10 ~
The rare earth-containing alloy powder of the present invention having a size of 500 μm is obtained. Ten
If the thickness is less than μm, the amount of oxygen in the alloy increases, and excellent magnet characteristics cannot be obtained. Further, if it is 500 μm or more, the diffusion reaction at the time of reduction is often insufficient, and α-Fe phase and the like appear in the magnet, so that iHc is lowered and the squareness of the demagnetization curve is deteriorated. The preferable particle size of the present invention is 20 to 300 μm in view of workability and magnet characteristics in the subsequent magnetizing step.
When the FeBR-based sintered magnet as the final product is subjected to polishing, the above composition alloy and the polishing powders thereof are released, and these polishing powders can also be used as a starting material for the reduction reaction. The obtained alloy powder is R: 12.5 to 20 atomic% R ₁ : 0.05 to 5 atomic% B: 4 to 20 atomic% Fe: 60 to 83.5 atomic% (where R ₁ is a heavy rare earth element Gd, Tb, Dy, One or more of Ho, Er, Tm and Yb, and R ₂ is 80% or more of one or more of Nd and Pr (up to 100
%), The balance (20 to 0%) is R = R ₁ + R ₂ (atomic%) as at least one kind of rare earth element containing Y other than R ₁ ), and the main phase (specific phase is 80% by volume or more) is a tetragonal crystal with an oxygen content of 10,000 ppm or less, a carbon content of 1000 ppm or less, and a calcium content of 2000 ppm or less.

The rare earth alloy powder in the present invention is finely pulverized as it is during the production of the R ₁ -R ₂ -Fe-B magnet alloy, followed by press molding → sintering (normal pressure or pressure sintering) aging treatment. It can be made into a permanent magnet by a metallic method. This fine pulverization is carried out by using an attritor, a ball mill, a jet mill, etc., preferably 1 to 20 μm, more preferably 2 to 10 μm.
To In order to manufacture an anisotropic magnet, particles can be oriented and shaped in a magnetic field. When the rare earth alloy powder of the present invention is used, the alloy is melted more than in the case of producing a permanent magnet from a raw material lump such as a rare earth metal lump, iron and boron.
It has the advantages that the manufacturing process of magnets such as casting → coarse crushing can be omitted, and the price of product magnets is low because cheap starting materials are used, and practical permanent magnet materials can be easily manufactured on a mass production scale. From the point of view, the economic effect is great.

Oxygen contained in the alloy powder of the present invention forms a rare earth oxide by combining with the rare earth element that is most easily oxidized, and when the oxygen content exceeds 10,000 ppm, 4% as an oxide (R ₂ O ₃ ) in the permanent magnet. This is not preferable because the magnetic properties, especially the coercive force, are lower than 10 kOe. The oxygen content is preferably 6000 ppm or less, more preferably 4000 ppm or less.

If the carbon content exceeds 1000 ppm, it will remain in the permanent magnet as carbides (RC ₂ etc.) as in the case of oxygen, and the squareness of the demagnetization curve will be reduced, and the coercive force will be 10 kOe or less. The carbon content is preferably 600 ppm or less.

Further, if the calcium content exceeds 2000 ppm, a large amount of extremely reducing Ca vapor is generated in the sintering process during the subsequent magnetization using this alloy powder, which will contaminate the heat treatment furnace. In some cases, the furnace wall of the heat treatment furnace is worn away, making industrially stable production impossible. In addition, the amount of Ca contained in the finished permanent magnet also increases, resulting in deterioration of magnet characteristics. The amount of Ca in the produced alloy is preferably 1000 ppm or less.

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

R (at least one of rare earth elements including Y) is an essential element as an alloy powder for producing a new R ₁ -R ₂ -Fe-B system permanent magnet, and if it is less than 12.5 atomic% or less, Fe precipitates in the system alloy compound and the coercive force decreases sharply. When R exceeds 20 atom%, the coercive force shows a large value of 10 kOe or more, but the residual magnetic flux density Br decreases (BH) max20MGO
It becomes impossible to obtain the required Br more than e. Therefore, the amount of the rare earth element R is set in the range of 12.5 atomic% to 20 atomic%. R ₁
The amount of R forms part of R above. R ₁ content is only 0.05 atomic%
Hc increases even in the presence of, and the squareness of the demagnetization curve is also improved and (BH) max increases. Therefore, the lower limit of the R ₁ amount is 0.05 considering the effect of increasing iHc and the effect of increasing (BH) max.
Atomic% or more. IHc rises as the amount of R ₁ increases, and (BH) max decreases gradually with a peak at 0.4 atom%, but even if the content of 3 atom% is contained, (BH) max increases.
Indicates 30 MGOe or more.

For applications in which stability is particularly required, it is advantageous that the iHc is higher, that is, the content of R ₁ is larger. However, the elements composing R ₁ are contained only in rare earth ores, and their oxides are also very expensive. Therefore, the upper limit is 5
Atomic% Further, as R ₁ is Dy, Tb is preferable. R ₂
Is at least 80% of R ₂ and the balance is at least one rare earth element other than R ₁ including Y. However, Sm and La should be as small as possible.

When the B content is 4 atomic% or less, iHc becomes 10 kOe or less.
In addition, increasing B content also increases iHc as does increasing R content, but Br decreases. To be (BH) max20MGOe or more, B20 atomic% or less is required. Therefore, the amount of B is
The range is from 4 atom% to 20 atom%.

Fe is an essential element as an alloy powder for producing a new R ₁ -R ₂ -Fe-B system permanent magnet, but the residual magnetic flux density Br decreases if it is less than 60 atomic%, and if it exceeds 83.5 atomic%, Since a high coercive force cannot be obtained, the Fe content is limited to 60 atom% to 83.5 atom%.

Further, the alloy powder according to the present invention can tolerate the presence of impurities inevitable in industrial production in addition to R, B and Fe. For example, 2
P content of not more than 2% by atom, S of 2% by atom, Cu of not more than 2% by atom, and even if the total amount of 2% by atom or less is contained, practical magnetic properties are exhibited, and the manufacturability of magnet alloy is improved and the price is reduced. It is possible. However, since these elements generally lower Br, it is preferable that the amount is small (for example, 0.5 atomic% or less, more preferably 0.1 atomic% or less).
Less than) and Br9kG or more. Furthermore, the R / B
・ Partially replacing Fe in the Fe alloy, 5.0 atomic% or less Al, 3.0 atomic% or less Ti, 6.0 atomic% or less Ni, 5.5 atomic% or less V, 4.5 atomic% or less Cr, 5.0 atomic% Mn below, 5.0 at% or less Bi, 9.0 at% or less Nb, 7.0 at% or less Ta, 5.2 at% or less Mo, 5.0 at% or less W, 1.0 at% or less Sb, 3.5 at% or less Of Ge, 1.5 atomic% or less of Sn, 3.3 atomic% or less of Zr, 3.3 atomic% or less of Hf, and 5.0 atomic% or less of Si by adding at least one of them, the high coercive force of the permanent magnet alloy is increased. It will be possible.

It is indispensable for the magnet to exhibit high magnetic characteristics that the main phase (the characteristic phase is 80% by volume or more, preferably 90% by volume or more, more preferably 95% by volume or more) is a tetragonal crystal phase.

The above-mentioned additional elements generally have the effect of increasing iHc and increasing the squareness of the demagnetization curve, but as the amount of addition increases, Br
Is decreasing. Br9 to have more than (BH) max20MGOe
Since kG or more is required, the upper limit of each addition amount (and in the case of mixed addition) is determined to be less than or equal to the above value except for Bi, Ni, and Mn. For Bi, its high vapor pressure, Ni, Mn
Is set from the viewpoint of iHc. Also, Si
Has the effect of increasing the Curie temperature. In the case of adding two or more elements, the upper limit of the total addition amount is less than or equal to the maximum value among the upper limits of the elements actually added. For example, when Ti, Ni, and Nb are added, it becomes 9% or less of Nb. Of the additional elements, V, Nb, Ta, Mo,
W, Cr and Al are preferred. The content of the additional element is preferably small, and generally 3 atom% or less is effective (in the case of Al, 0.1 to
3 atomic%, especially 0.2-2 atomic%). It should be noted that these additive elements may be mixed in the starting material as metal powder, or as an oxide, or an alloy or mixed oxide with other constituent elements.

This magnetic phase is composed of FeBR tetragonal compound crystals, and the grain boundaries are surrounded by the nonmagnetic phase. The non-magnetic phase is mainly composed of R-rich phase (R metal). When the amount of B is large, a B-rich phase may be partially present. The existence of the non-magnetic phase 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 the non-magnetic phase is effective, for example, 1 vol% or more is a sufficient amount. It is considered that the lattice parameters of the tetragonal crystal are a about 8.8Å and c about 12.2Å, and the central composition thereof is R ₂ Fe ₁₄ B. The alloy powder of the present invention is generally crystalline, and typically, the grain size of crystals constituting the powder grain is about 1 μm or more (provided that the powder grain size is not less than this). The amount of the tetragonal phase can be measured using the intensity of X-ray diffraction or an X-ray microanalyzer. Furthermore, the sintered permanent magnet using this alloy powder is crystalline, and the average crystal grain size of the RFeB tetragonal phase is 1 to 40 μm.
m (more preferably 3 to 20 μm) is desirable for excellent permanent magnet characteristics.

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

〔Example〕

Example 1 Nd ₂ O ₃ powder: 56.2gr Dy ₂ O ₃ powder: 4.3gr Ferroboron powder (19.5wt% B-Fe alloy powder): 6.1gr Fe powder: 59.4gr Metal Ca: 53.6gr (of stoichiometric ratio) 2.5 times) CaCl ₂ : 2.6gr (4.3wt% of rare earth oxide raw material) total of 182.2gr, 30.5% Nd-3.6% Dy-6
4.75% Fe1.15% B (weight%) [14.1% Nd-1.5% Dy-77.3% Fe-7.1% B (atomic%)]
Aiming at the compositional alloy of No. 1, the mixture was mixed using a V-type mixer.
Then, the compressed body of the mixed raw material was filled in a stainless steel container, charged into a muffle furnace, and then heated in an argon gas stream in the container. After maintaining a constant temperature of 1150 ° C for 3 hours, the furnace was cooled to room temperature. The obtained reduction reaction product was coarsely crushed into 8 meh through and then put into 10 ion-exchanged water to remove calcium oxide (CaO), CaO.2CaCl ₂ and unreacted residual calcium in the reaction product. The reaction product was made into (OH) ₂ ) and disintegrated into a slurry. After stirring for 1 hour,
The suspension was allowed to stand for 30 minutes to disperse the calcium hydroxide, water was poured again, and the steps of stirring, standing and suspension vapor were repeated several times. Nd-Dy-Fe-B separated and collected in this way
The system alloy powder was dried in a vacuum to obtain 86 gr of the rare earth alloy powder for a magnet material of the present invention having a particle size of 20 to 300 μm.

Results of component analysis, as follows Nd: 30.4wt% Dy: 3.5wt% Fe: 63.6wt% B: 1.2wt% Ca: 800ppm O 2: 4800ppm C: desired alloy powder 750ppm was obtained. According to the X-ray diffraction pattern measurement, the alloy powder was a tetragonal intermetallic compound having a = 8.77Å, c = 12.19Å as a main phase of 95% or more.

This powder is pulverized to a powder with an average particle size of 2.70 μm. 1.
A compact was formed in a magnetic field of 10 kOe at a pressure of 5 t / cm ² . After that, sintering at 1120 ℃ -2 hours in Ar gas flow and 600 ℃ -1
Aging treatment for time was performed to prepare a permanent magnet sample.

Excellent magnet characteristics of Br = 11.4kG iHc = 10.6kOe (BH) max = 30.4MGOe were obtained.

Example 2 Nd ₂ O ₃ powder: 44.9gr Dy ₂ O ₃ powder: 1.4gr Ferroboron powder (19.0wt% B-Fe alloy powder): 6.1gr Fe powder: 62.3gr Metal Ca: 41.3gr (of stoichiometric ratio) 2.5 times) CaCl ₂ : 2.3gr (5.0wt% of rare earth compound raw material) 158.3gr in total, 30.5% Nd-1.2% Dy-67% Fe-1.2% B (wt%) [13.8% Nd- 0.5% Dy-78.5% Fe-7.2% B (atomic%)] In the same manner as in Example 1, aiming at a composition alloy, 1050 ° C-
After reduction treatment for 3 hours, 75 gr of the rare earth alloy powder for a magnet material of the present invention having a thickness of 20 to 500 μm was obtained.

As a result of the compositional analysis, the following alloy powder was obtained as follows: Nd: 29.4wt% Dy: 1.0wt% Fe: 68.6wt% B: 1.0wt% Ca: 490ppm O ₂ : 3300ppm C: 480ppm. According to the measurement of X-ray diffraction pattern, the alloy powder was a tetragonal intermetallic compound having a = 8.79Å, c = 12.20Å as a main phase of 92% or more.

When a permanent magnet material was prepared in the same manner as in Example 1, excellent magnet characteristics of Br = 12.4 kG iHc = 10.3 kOe (BH) max = 36.2 MGOe were obtained.

Example 3 Nd ₂ O ₃ powder: 36.1gr La ₂ O ₃ powder: 3.7gr Dy ₂ O ₃ powder: 5.1gr Gd ₂ O ₃ powder: 3.0gr Fe powder: 57.5gr ferroboron powder (19.0wt% B-Fe alloy) Powder): 8.8gr Metal Ca: 54.8gr (3.2 times stoichiometric ratio) CaCl ₂ : 4.8gr (10wt% of rare earth oxide raw material) 173.8gr in total, 24.5% Nd-2.5% La- 4.3% Dy-2.4% Gd-64.6% Fe-1.7
% B (% by weight) [11% Nd-1.2% La-1.7% Dy-1% Gd-75% Fe-10.1%
B (atomic%)] Aiming at a composition alloy, powder 85gr having a particle size of 30 to 500 μm was obtained in the same manner as in Example 1.

Results of component analysis, as follows Nd: 24.3wt% La: 2.4wt% Dy: 4.5wt% Gd: 2.4wt% Fe: 64.7wt% B: 1.6wt% Ca: 1000ppm O 2: 5500ppm C: 500ppm desired Alloy powder was obtained. According to the X-ray diffraction pattern measurement, the alloy powder was a tetragonal intermetallic compound having a = 8.80Å, c = 12.24Å as a main phase of 89% or more.

The obtained powder was finely pulverized to obtain a powder having an average particle size of 3.5 μm, and a compression molding was performed in a magnetic field of 10 kOe at a pressure of 1.5 t / cm ² . After that, sintering was performed at 1100 ° C. for 2 hours and aging treatment was performed at 600 ° C. for 1 hour to prepare a permanent magnet sample.

Excellent magnet characteristics of Br = 10.5kG iHc = 13.5kOe (BH) max = 24.7MGOe were obtained.

Example 4 Nd ₂ O ₃ powder: 43.8gr Dy ₂ O ₃ powder: 4.5gr Fe powder: 59.2gr Fe-B powder (19.0wt% B-Fe alloy powder): 7.0gr Al ₂ O ₃ (alumina) powder: 1.0gr Metal Ca: 49.3gr (2.8 times the stoichiometric ratio) CaCl ₂ : 3.5gr (7wt% of oxide raw material) using a powder total of 168.2gr 29.7% Nd-3.7% Dy-64.8% Fe- 1.3% B-0.4% Al (wt%) [13.5% Nd-1.5% Dy-76.0% Fe-8% B-1.0% Al (atomic%)] Similar to Example 1, aiming at a composition alloy 1080 ℃ × 3
After reduction treatment for an hour, 83 gr of 30 to 500 μm alloy powder was obtained.

Results of component analysis, as follows Nd: 29.6wt% Dy: 3.7wt% Fe: 64.8wt% B: 1.3wt% Al: 0.5wt% Ca: 850ppm O 2: 3200ppm C: desired alloy powder 780ppm replacement Was given. According to the X-ray diffraction pattern measurement, the alloy powder was a tetragonal intermetallic compound having a = 8.79Å, c = 12.12Å as a main phase of 92% or more.

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

Excellent magnet characteristics of Br = 11.3kG iHc = 17.5kOe (BH) max = 29.8MGOe were obtained.

Example 5 Nd ₂ O ₃ powder: 43.4gr Dy ₂ O ₃ powder: 4.4gr Fe powder: 57.9gr Ferroboron powder (19.0wt% B-Fe alloy powder): 6.9gr Ferroniobium powder (67.3wt% Nb-Fe alloy powder) ): 2.1gr Metal Ca: 42.7gr (2.5 times the stoichiometric ratio) CaCl ₂ : 0.8gr (12wt% of rare earth compound raw material) 158.2gr in total, 29.4% Nd-3.7% Dy-64.2% Fe -1.3% B-1.4 Nb (wt%) [12.5% Nd-1.5% Dy-77.0% Fe-8% B-1% (atomic%)] In the same manner as in Example 3, aiming for a composition alloy, 20 to 500μ
88 g of m powder was obtained.

As a result of component analysis, the following is obtained: Nd: 29.2wt% Dy: 3.7wt% Fe: 64.5wt% B: 1.2wt% Nb: 1.4wt% Ca: 500ppm O ₂ : 4300ppm C: 320ppm Was given. According to the measurement of X-ray diffraction pattern, it was an alloy powder having a tetragonal intermetallic compound having a = 8.80Å, c = 12.23Å as a main phase of 90% or more.

A permanent magnet material was produced in the same manner as in Example 3.

Excellent magnet characteristics of Br = 11.5kG iHc = 14.5kOe (BH) max = 30.5MGOe were obtained.

〔effect〕

As described in detail, according to the present invention, an alloy powder having the same composition for producing a R ₁ —R ₂ —Fe—B magnet can be manufactured at low cost by using rare earth oxide and boron oxide raw materials as starting materials. The obtained R ₁ -R ₂ -Fe-B system permanent magnet having excellent properties is obtained by using it, and isolation and purification of rare earth metal from the step of magnet production-melting of alloy-cooling (usually casting)- It is possible to omit the crushing process for manufacturing the predetermined alloy powder, and to shorten the magnet manufacturing process. This shortening of the process is extremely useful in avoiding inclusion of undesired components or impurities (oxygen etc.) in the process. This is because it is difficult to prevent oxygen and the like from being mixed in the processes from melting to crushing, which requires complicated process control, which is one of the causes of an increase in manufacturing cost.

Furthermore, as the rare earth oxide, it is not always necessary to use those separated as the respective rare earth oxides, and it is possible to add a rare earth oxide mixture corresponding to the target composition or a partial lacking rare earth oxide as a starting material. In the rare earth oxide separation process itself, it is possible to shorten the process and reduce the cost.

Further, the alloy of the present invention is effective in that it can be directly obtained by the direct reduction method as an alloy having a tetragonal phase which is essential for magnetic properties as a main phase, and it is also a great advantage that it can be obtained as a powder. .

A method of obtaining a rare earth magnet from an alloy powder obtained by reducing a rare earth oxide is known as an Sm / cobalt magnet. However, since Sm / cobalt magnets require a high reduction temperature of 1150 to 1300 ° C, it causes grain growth, and it is difficult to obtain a powder with a uniform grain size at the time of disintegration, and it reacts with the container used during reduction and causes significant damage. .

Based on the above, the effect of the present invention is recognized to be remarkable.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location H01F 1/06 (72) Inventor Setsuo Fujimura 2-15-17 Egawa, Shimamoto-cho, Mishima-gun, Osaka Sumitomo Yamazaki Seisakusho Co., Ltd. (56) References JP-A-58-132105 (JP, A)

Claims (2)

[Claims] 1. A rare earth R, containing a trace amount of calcium used as a reducing agent for a raw material containing a compound of the rare earth R,
A reduced calcium powder containing B and Fe as main components and having the following composition, R: 12.5 to 20 atom%, R ₁ : 0.05 to 5 atom%, B: 4 to 20 atom%, Fe: 60 to 83.5 atom. %, (Where R ₁ is a heavy rare earth element Gd, Tb, Dy, Ho, Er, Tm, Yb
Of at least 80% of one or more of Nd and Pr for R ₂ ,
The rest is at least one rare earth element containing Y other than R ₁ and R = R ₁ + R ₂ (atomic%)), oxygen content 10,000 ppm or less, carbon content 1000 ppm or less, and calcium content 2000 ppm or less And a rare earth-containing alloy powder characterized in that the main phase (specific phase is 80 vol% or more) is tetragonal. 2. A rare earth R, containing a trace amount of calcium used as a reducing agent for a raw material containing a compound of the rare earth R,
A reduced calcium powder containing B and Fe as main components and having the following composition, R: 12.5 to 20 atom%, R ₁ : 0.05 to 5 atom%, B: 4 to 20 atom%, Fe: 60 to 83.5 atom. %, (Where R ₁ is a heavy rare earth element Gd, Tb, Dy, Ho, Er, Tm, Yb
Of at least 80% of one or more of Nd and Pr for R ₂ ,
The rest is at least one rare earth element containing Y other than R ₁ and R = R ₁ + R ₂ (atomic%)), oxygen content 10,000 ppm or less, carbon content 1000 ppm or less, and calcium content 2000 ppm or less And the main phase (the specific phase is 80 vol% or more) is a tetragonal crystal, and partially substitutes for Fe, 5.0 atomic% or less of Al, 3.0 atomic% or less of Ti, 5.5 atomic% or less of V, 6.0 atomic% or less Ni, 4.5 atomic% or less Cr, 5.0 atomic% or less Mn, 5.0 atomic% or less Bi, 9.0 atomic% or less Nb, 7.0 atomic% or less Ta, 5.2 atomic% or less Mo, 5.0 Of atomic% or less W, 1.0 atomic% or less Sb, 3.5 atomic% or less Ge, 1.5 atomic% or less Sn, 3.3 atomic% or less Zr, 3.3 atomic% or less Hf, and 5.0 atomic% or less Si A rare earth-containing alloy powder comprising at least one additive.