JPH0791564B2 - Rare earth containing alloy powder - Google Patents

Description

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

[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.).

However, the Curie temperature of this R-Fe-B alloy magnet is 310
Since it is relatively low at ℃, and lacks stability under operating conditions above room temperature, it has been attempted to improve the stability against temperature by substituting a part of Fe with Co and raising the Curie temperature. (Japanese Patent Laid-Open No. 59-64733) [Problems to be solved by the invention] The present applicant has further proposed Nd as an improvement of the R-Fe-Co-B magnet.
Energy content of (BH) max = 20MGOe or more by substituting 5 atomic% or less of at least one heavy rare earth element of Gd, Tb, Dy, Ho, Er, Tm, Yb for light rare earth elements such as Pr and Pr. while having the coercive force (iHc) drastically improved over 10 kOe, above room which can also be used in 100 to 150 ° C. in a temperature environment _{R 1 -R 2 -Fe-Co -} B based rare earth magnet (Where R ₁ is
One or more of the heavy rare earth elements of Gd, Tb, Dy, Ho, Er, tm, Yb,
R ₂ is Nd and / or Pr of 80 atomic% or more and the rest is Y other than R _1.
Which is at least one of the rare earth elements including). (Japanese Patent Application No. 58-141850).

The starting material for producing the R ₁ -R ₂ -Fe-Co-B rare earth magnet is a purity of 99.5 produced by an electrolytic method or a thermal reduction method.
% Or more rare earth metals, purity 99.9% or more of electrolytic iron, electrolytic cobalt, and expensive metal lumps with few impurities such as boron are 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 advanced classification and refining technology,
Its production efficiency is poor and its price is extremely high.

Therefore, the R ₁ -R ₂ -Fe-Co-B system permanent magnet has a high iHc and high performance and is very effective as a practical permanent magnet material, but the magnet price 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.
It is an object to provide (R ₁ -R ₂ ) -Fe-Co-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 reduction having the following composition containing rare earth R, B, Fe, and Co as the main components, contains a trace amount of calcium used as a reducing agent for a raw material containing a compound of rare earth R. Powder, R: 12.5 to 20 atomic% (R ₁ : 0.05 to 5 atomic% of R), B: 4 to 20 atomic%,
Fe: 45 to 82 atomic% and Co: 35 atomic% or less (excluding 0%), (wherein R ₁ is a heavy rare earth element Gd, Tb, Dy, Ho, Er,
One or more of Tm and Yb, R ₂ has Nd and / or Pr of 80 atomic%
As described above, the rest is at least one kind of rare earth element containing Y other than R ₁ and R = R ₁ + R ₂ (atomic%)), oxygen content is 10000 ppm or less, carbon content is 1000 ppm or less, and calcium content The rare earth-containing alloy powder is characterized in that the amount is 2000 ppm or less and the main phase (specific phase is 80 vol% or more) is tetragonal.

In a second aspect, there is provided a calcium-reduced 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 has rare earths R, B, Fe, and Co as main components. , R: 12.5 to 20 atom% (of R
R ₁ : 0.05 to 5 atomic%), B: 4 to 20 atomic%, Fe: 45 to 82 atomic%, and Co: 35 atomic% or less (excluding 0%) (where R ₁ is a heavy rare earth element). At least one of Gd, Tb, Dy, Ho, Er, Tm, and Yb, R ₂ is at least 80 atomic% of Nd and / or Pr, and the remaining is at least one rare earth element containing Y other than R _1. age,
R = R ₁ + R ₂ (atomic%)), oxygen content 10,000 ppm or less, carbon content 1000 ppm or less, and calcium content 2
000ppm or less, and the main phase (specific phase is 80vol% or more) is tetragonal, partially replacing Fe, 5.0 atomic% or less A1, 3.0 atomic% or less Ti, 5.5 atomic% or less 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 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 Ge, 1.5 at% or less Sn, 3.3 at% or less Zr, 3.3 H less than atomic%
At least one of f and Si of 5.0 atomic% or less is added and contained.

Note that, from both viewpoints, the above-mentioned reduced calcium powder is a rare earth whose main component is a rare earth R reduced by using calcium as a reducing agent by adding calcium to a raw material containing a rare earth compound such as a rare earth oxide. Contains alloy powder. Calcium includes a simple substance or a compound.

By using the R ₁ -R ₂ -Fe-Co-B alloy powder of the present invention (including the one containing a predetermined amount of a predetermined element in place of Fe partially according to the second aspect of the present invention) (BH ) Max20MGO
The temperature coefficient (α) of the residual magnetic flux density (Br) is increased from the conventional R-Fe-B or R ₁ -R ₂ -by increasing the Curie temperature of the magnet while maintaining the magnet characteristics of e or more and iHc10kOe or more. Fe-B
An improved permanent magnet can be obtained over the magnet alloy (α = about 0.14% / degree, but at room temperature to 150 ° C). Br of 5 atomic% or more of Co
Has a temperature coefficient α of about 0.1% / degree or less.

Further, according to the present invention, the R ₁ -R ₂ -Fe-Co-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 inexpensive Nd ₂ O ₃ and Pr ₆ O _{l 1} and heavy rare earth oxides such as Tb ₃ O ₄ and Dy ₂ O ₃ which are inexpensive. Thing and Fe powder, Co
Powder, pure boron powder, Fe-B powder or B ₂ O ₃ powder as a starting material, metal calcium and / or calcium hydride as a reducing agent, and calcium chloride (CaCl 3) for facilitating the decomposition of the reduction reaction product. It is manufactured by the process using ₂ ). 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. The shortening of the magnet manufacturing process by the use of this alloy powder also becomes possible, cheap price R ₁ -
Since it is possible to provide an R ₂ —Fe—Co—B rare earth magnet, its economic 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, Co powder, and Fe-B powder to form R ₁ from rare earth oxides.
-R ₂ -Fe-Co-B alloy powder is good yield recovered can be effectively used a rare earth oxide raw materials. Metal as a reducing agent
It is also possible to use calcium hydride instead of Ca.

The content of B (boron) component in the raw material powder is R ₁ -R ₂ -Fe.
-Effective for lowering the reduction / diffusion reaction temperature when producing a Co-B alloy powder, and facilitating the reduction / diffusion reaction of the present alloy powder. Further, the inclusion of the Co component becomes a part of the intermetallic compound (having a tetragonal structure) indispensable to this permanent magnet, and has the effect of significantly improving the oxidation resistance of the alloy powder.

Therefore, in order to obtain a large amount of raw material alloy powder for R ₁ -R ₂ -Fe-Co-B magnets from an inexpensive rare earth oxide on an industrial scale, an inexpensive alloy powder of Fe and B, which is produced in large quantities today, is used. The present invention has led to the invention of the R ₁ -R ₂ -Fe-Co-B alloy powder in the specific composition range of the present invention, considering that production is 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 O _{l 1} ) and Tb oxide (Tb
₄ O ₇ ) and at least one heavy rare earth (R ₁ ) oxide such as Dy oxide (Dy ₂ O ₃ ), iron (Fe) powder, cobalt (Co) powder and pure boron powder, ferroboron (Fe-B) ) powder, the three least one raw material powder of the boron oxide (B ₂ O ₃₎ powder of R: 12.5 to 20 atomic% (of which R _1: 0.05 to 5 atomic%), B: 4 to 20 atomic%, Fe : 45 to 82 atom% and Co: 35 atom% or less (excluding 0%) (wherein R ₁ is one or more of heavy rare earth elements Gd, Tb, Dy, Ho, Er, Tm, Yb, R ₂ is 80 atomic% or more of Nd and / or Pr, and the remainder is at least one rare earth element containing Y other than R ₁ and R
= R ₁ + R ₂ (atomic%)) to obtain a 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 of the stoichiometrically required amount required to reduce the oxygen contained in the raw material mixed powder.
Double (weight ratio), preferably 1.5 to 2.5 times, more preferably 1.6 to 2.0 times, and the amount of CaCl ₂ is less than that of the rare earth oxide raw material.
-15% (weight ratio) (preferably 2-10%, more preferably 3-6%).

The mixed powder consisting of the above raw material powders such as rare earth oxide powder, Fe powder, Co powder, ferroboron powder, and Ca reducing agent was heated to 950 to 1200 ℃ (preferably 950 to 1100 ℃) in an argon inert gas atmosphere. The reduction / diffusion treatment is performed within a temperature range for a predetermined time (preferably 1 to 5 hours), and then cooled to room temperature to obtain a reduction reaction product. When this is crushed to an appropriate particle size, preferably 8 mesh (2.4 mm) or less and brought into contact with water (input), calcium oxide (CaO) in the reaction product,
CaO · 2CaCl ₂ and excess calcium become calcium hydroxide (Ca (OH) ₂ ), etc., and the reaction product disintegrates and becomes a mixed slurry with water. This slurry is mixed with water using Ca
By sufficiently removing the content, the rare earth-containing alloy powder of the present invention having a powder particle size of about 10 to 500 μm can be obtained. If it is less than 10 μm, the amount of oxygen in the alloy is large, and excellent magnet characteristics cannot be obtained. Further, if the thickness 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 decreases and the squareness of the demagnetization curve decreases. 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. The obtained alloy powder R: 12.5 to 20 atomic% (of R R _1: 0.05 to 5 atomic%), B: 4 to 20 atomic%, Fe: forty-five to eighty-two atomic%, and Co: 35 atomic% or less (However, 0% is excluded) (Here, R ₁ is one or more of the heavy rare earth elements Gd, Tb, Dy, Ho, Er, Tm, Yb, and R ₂ is 80 atomic% or more of Nd and / or Pr. (~Ten
0%), the rest (20 to 0%) consists of at least one rare earth element containing Y other than R ₁ and R = R ₁ + R ₂ (atomic%), and the main phase (80 vol% of the alloy) The above) 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-Co-B magnet alloy, and is subsequently subjected to press molding → sintering → aging treatment by a powder metallurgical method. Can be This fine pulverization is preferably carried out using an attritor, ball mill, jet mill, etc.
-20 μm, more preferably 2-10 μm. In order to manufacture an anisotropic magnet, particles can be oriented and shaped in a magnetic field. By using the rare earth alloy powder of the present invention, it is possible to omit the manufacturing process of the magnet such as alloy melting → casting → coarse crushing as compared with the case of manufacturing a permanent magnet from a raw material mass such as a rare earth metal mass, iron and boron. In addition, since the price of the product magnet is low because a cheap starting material is used, the practical permanent magnet material can be easily manufactured on a mass production scale, and thus the economical effect is large.

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 10 kOe 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, more preferably 400 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 completed 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-Co-B based permanent magnet, and if it is less than 12.5 atomic%. Α-Fe is precipitated in this alloy compound and the coercive force sharply decreases. When R exceeds 20 atomic%, the coercive force shows a large value of 10 kOe or more, but the residual magnetic flux density Br decreases (BH ) Max2
You will not be able to obtain the required Br above 0 MGOe. Therefore, the amount of the rare earth element R is set in the range of 12.5 atomic% to 20 atomic%. The amount of R ₁ forms part of R above. R ₁ amount is only 0.05
Even in the presence of atomic%, Hc increases, and the squareness of the demagnetization curve is also improved, and (BH) max increases. Therefore, the lower limit of the R ₁ amount is set to 0.05 atom% or more in consideration of the effect of increasing iHc and the effect of increasing (BH) max. IHc as R ₁ content increases
Increases, and (BH) max decreases gradually with a peak at 0.4 at%, but even if the content of (BH) max is 3 at%,
H) max 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
The total of Nd and Pr is 80% or more of R ₂ , and the rest is one or more rare earth elements containing Y other than R ₁ . 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%.

The addition of Co has the effect of increasing the Curie temperature (Tc) of the R ₁ -R ₂ -Fe-Co-B system permanent magnet (Fig. 1). The Curie temperature continuously rises as the amount of Co added increases. Therefore, Co is effective even in a small amount, and the lower limit is not particularly limited, but is preferably 0.1 atom% or more. Also, C
When the amount exceeds 35 atom%, the saturation magnetization and coercive force of the permanent magnet decrease, and the value becomes lower than 20MGOe. In the FeBR system, the temperature coefficient of Br is about 0.13% / ° C (room temperature to 150 ° C), but it becomes about 0.1% / ° C when the content of Co is 5 atomic% or more. It should be noted that when Co is 25 at% or less, it contributes to the Curie temperature increase without substantially deteriorating other properties, and at about 20 at% (17 to 23 at%)
It also increases iHc. Most preferably, the amount of Co is 5 to 6 atomic%.

Fe content is an essential element as an alloy powder for producing a new R ₁ -R ₂ -Fe-Co-B system permanent magnet, but if it is less than 45 atomic%, the residual magnetic flux density Br decreases, and 82 atomic% If it exceeds, a high coercive force cannot be obtained, so the Fe content is limited to 60 atom% to 82 atom%. The Fe content is more preferably 45 to 80 atomic%. Further, the total amount of Fe and Co is preferably 60 atom% or more, and most preferably the Fe amount is 60 atom% or more.

Further, the alloy powder according to the present invention can tolerate the presence of impurities that are unavoidable in industrial production in addition to R, B, Fe and Co. For example, P of 2 atomic% or less, S of 2 atomic%, S of 2 atomic% or less
Even if the total amount of Cu is 2 atomic% or less, the magnetic properties are still practical, and it is possible to improve the manufacturability of magnet alloys and reduce the cost. However, since these elements generally lower Br, it is preferable that the amount thereof be small (for example, 0.5 atomic% or less, more preferably less than 0.1 atomic%), and Br 9 kG or more. further,
Partial substitution for Fe in the R, Fe, Co and B alloys, 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% 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 Permanent addition of at least one of 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 It is possible to increase the coercive force of the magnet alloy.

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 specified to be equal to or less than the above value, except for Bi, Ni, and Mn. For Bi, its high vapor pressure, Ni,
An upper limit is set for Mn from the viewpoint of iHc. Also, S
i 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, Nb is added, Nb
Of 9% or less. Especially, among the additive elements, V, Nb, Ta, M
O, W, Cr and Al are preferred. The content of the additional element is preferably small, and generally 3 atom% or less is effective (0.1% for Al).
.About.3 atom%, especially 0.2 to 2 atom%). 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.

It is indispensable that the main phase (80% by volume or more of the alloy, preferably 90% by volume or more, more preferably 95% by volume or more) of the crystal phase is a tetragonal crystal in order to exhibit high magnetic properties as a magnet.

This magnetic phase is composed of FeCoBR tetragonal compound crystals, and the grain boundaries are surrounded by the nonmagnetic phase. Non-magnetic phase is mainly R
It consists of a 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, Co) l ₄ B. This alloy powder is generally crystalline, and the grain size of the crystal that constitutes the powder grain is typically about 1 μm or more (provided that the powder grain size is not less than this). The amount of tetragonal phase is X
It can be measured using the intensity of line diffraction or an X-ray microanalyzer. Further, the sintered permanent magnet using this alloy powder is crystalline, and the average crystal grain size of the R (Fe, Co) B tetragonal phase is 1 to 40 μm (more preferably 3 to 20 μm). Desirable for excellent permanent magnet properties.

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: 54.8gr Dy ₂ O ₃ powder: 5.6gr Ferroboron powder (19.5wt% B-Fe alloy powder): 6.5gr Fe powder: 42.6gr Co powder: 18.6gr Metal Ca: 53.5gr ( 2.5 times the stoichiometric ratio) CaCl ₂ : 2.6gr (4.3wt% of rare earth oxide raw material) 184.2gr in total, 30.0% Nd-3.6% Dy-4
Aiming at a composition alloy of 7.7% Fe-17.5% Co-1.12% B (weight%) [14.0% Nd-1.5% Dy-57.5% Fe-20% Co-7.0% B (atomic%)], V type Mix using a 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. 8mesh of the obtained reduction reaction product
After roughly crushing into a through, put into 10 ion-exchanged water to remove calcium oxide (CaO), CaO · 2CaCl ₂ , and unreacted residual calcium in the reaction product calcium hydroxide (Ca (OH) ₂ ).
The reaction product was disintegrated into a slurry. After stirring for 1 hour, the mixture was left standing for 30 minutes to drain the calcium hydroxide suspension, water was poured again, and the steps of stirring, standing, and suspension removal were repeated several times. Nd- separated and collected in this way
Dy-Fe-Co-B type alloy powder is dried in vacuum to 20 ~ 300
84 μm of the rare earth alloy powder for magnet materials of the present invention having a size of 84 μm was obtained.

As a result of the component analysis, as shown below, Nd: 30.2 wt% Dy: 3.3 wt% Fe: 48.2 wt% Co: 15.8 wt% B: 1.1 wt% Ca: 800 ppm O ₂ : 4100 ppm C: 670 ppm of the desired alloy powder. Was given. According to the X-ray diffraction pattern measurement, the alloy powder was a tetragonal intermetallic compound having a = 8.76Å, c = 12.15Å as a main phase of 95% or more.

This powder is pulverized to a powder with an average particle size of 2.50 μm. 1.
A compact was formed in a magnetic field of 10 kOe at a pressure of 5 t / dcm 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 = 11.5kG iHc = 16.3kOe (BH) max = 31.7MGOe were obtained. Also, of this alloy magnet
The Br temperature coefficient α was 0.075% / ° C. (room temperature −150 ° C.).

Example 2 Nd ₂ O ₃ powder: 47.0gr Dy ₂ O ₃ powder: 1.6gr Ferroboron powder (19.0wt% B-Fe alloy powder): 6.4gr Fe powder: 61.2gr Co powder: 4.4gr Metal Ca: 43.3gr ( 2.5 times the stoichiometric ratio) CaCl ₂ : 2.5gr (5.0wt% of rare earth oxide material) 166.4gr in total, 30.4% Nd-1.2% Dy-6
2.7% Fe-4.5% Co-1.2% B (wt%) [13.8Nd-0.5% Dy-73.5% Fe-5% Co-7.2% B (atomic%)] Aiming at a composition alloy, as in Example 1 Similarly, at 1070 ℃-
After reduction treatment for 3 hours, 79 gr of the rare earth alloy powder for a magnet material of the present invention having a particle size of 20 to 500 μm was obtained.

Results of component analysis, as follows Nd: 29.5wt% Dy: 1.1wt% Fe: 61.3wt% Co: 4.1wt% B: 1.0wt% Ca: 490ppm O 2: 3300ppm C: desired alloy powder 480ppm replacement Was given. According to the X-ray diffraction pattern measurement, the alloy powder was a tetragonal intermetallic compound having a = 8.79Å, c = 12.18Å as a main phase of 93% or more.

A permanent magnet material was prepared in the same manner as in Example 1, and excellent magnet characteristics of Br = 12.5 kG iHc = 12.1 kOe (BH) max = 37.4 MGOe were obtained. The temperature characteristic of this magnet alloy was α = 0.09% ° C.

Example 3 Nd ₂ O ₃ powder: 36.3gr CeO ₂ powder: 9.2gr Dy ₂ O ₃ powder: 3.1gr Gd ₂ O ₃ powder: 3.0gr Fe powder: 49.9gr Co powder: 8.0gr Ferroboron powder (19.0wt% B -Fe alloy powder): 9.0gr Metal Ca: 68.5gr (3.2 times the stoichiometric ratio) CaCl ₂ : 5.2gr (10wt% of rare earth oxide raw material) 192.2gr in total, 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-65% Fe-10% Co-
10% B (atomic%)] Aiming at a composition alloy, powder 87gr having a particle size of 30 to 500 μm was obtained in the same manner as in Example 1.

As a result of component analysis, as shown below, Nd: 24.1wt% Ce: 4.0wt% Dy: 2.3wt% Gd: 2.2wt% Fe: 55.9wt% Co: 8.8wt% B: 1.6wt% Ca: 1100ppm O ₂ : 5500ppm C: 600 ppm of the desired alloy powder was obtained. According to the X-ray diffraction pattern measurement, it was an alloy powder having a tetragonal intermetallic compound having a = 8.80Å, c = 12.24Å as a main phase of 87% 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 = 10.7kG iHc = 10.4kOe (BH) max = 25.2MGOe were obtained.

〔effect〕

As described in detail, according to the present invention, an alloy powder having the same composition for producing an R ₁ —R ₂ —Fe—Co—B magnet is prepared by using a rare earth oxide and a boron oxide raw material as starting materials. R ₁ -R ₂ -Fe-Co with excellent properties obtained at low cost
-The B-type permanent magnet is obtained, and the isolation and purification of the rare earth metal from the magnet manufacturing process-The melting of the alloy-The cooling (usually casting) -The crushing of the predetermined alloy powder manufacturing process can be omitted, and the magnet manufacturing process can be shortened. To do. This shortening of fixation is extremely useful in avoiding contamination of undesirable components or impurities (oxygen etc.) during 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, but it is not necessary to use an oxide mixture close to the target composition or a partial deficiency rare earth oxide as the starting material. Also in the oxide separation process itself, the process can be shortened and the cost can be reduced. Furthermore, the addition of Co raises the Curie temperature of the permanent magnet, improves the squareness of the demagnetization curve and oxidation resistance, improves the yield when the reduction reaction product collapses during the manufacturing process, and improves the acid resistance of the fine powder. It brings about chemical stability.

Further, the alloy of the present invention is very effective in that it can be directly obtained by the direct reduction method as an alloy having a tetragonal magnetic phase essential for magnetic properties as a main phase, and it is also a great advantage that it can be obtained as a powder. is there. 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, the Sm / cobalt magnet requires a high reduction temperature of 1150 to 1300 ° C, which causes grain growth and makes it difficult to obtain a powder having a uniform grain size at the time of disintegration, and significantly damages it due to the reaction with the container used for reduction.

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

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention Fe-xCo-8B-13.8Nd-1.0Dy.
3 is a graph showing the relationship between the amount of Co and the Curie temperature Tc (° C.) in the system of FIG.

─────────────────────────────────────────────────── ─── 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-59-64733 (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 calcium reduced powder containing B, Fe, and Co as main components and having the following composition, wherein R: 12.5 to 20 atom% (R ₁ : 0.05 to 5 atom% of R), B: 4 to 20 atom%, Fe: 45 to 82 atomic% and Co: 35 atomic% or less (excluding 0%), (where R ₁ is a heavy rare earth element Gd, Tb, Dy, Ho, Er, Tm, Yb).
One or more of the, at R ₂ is Nd and / or Pr is 80 atomic% or more, at least the remainder of rare earth elements including Y other than R ₁ 1
Seed, R = R ₁ + R ₂ (atomic%)), the main phase (80 vol% or more of the alloy), oxygen content 10000 ppm or less, carbon content 1000 ppm or less, and calcium content A rare earth-containing alloy powder characterized in that the content is 2000 ppm or less and 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 calcium reduced powder containing B, Fe, and Co as main components and having the following composition, wherein R: 12.5 to 20 atom% (R ₁ : 0.05 to 5 atom% of R), B: 4 to 20 atom%, Fe: 45 to 82 atomic% and Co: 35 atomic% or less (excluding 0%), (where R ₁ is a heavy rare earth element Gd, Tb, Dy, Ho, Er, Tm, Yb).
One or more of the, at R ₂ is Nd and / or Pr is 80 atomic% or more, at least the remainder of rare earth elements including Y other than R ₁ 1
Seed, R = R ₁ + R ₂ (atomic%)), the main phase (80 vol% or more of the alloy), oxygen content 10000 ppm or less, carbon content 1000 ppm or less, and calcium content 2000ppm or less, and the main phase (specific phase is 80vol% or more) is a tetragonal crystal, partially replacing Fe, 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 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 W of 5.0 atomic% or less, Sb of 1.0 atomic% or less, Ge of 3.5 atomic% or less, Sn of 1.5 atomic% or less, Zr of 3.3 atomic% or less, Hf of 3.3 atomic% or less, and Si of 5.0 atomic% or less. At least one of the above is added and contained in the rare earth-containing alloy powder.