JPS60189902A - Alloy powder for rare earth-boron-iron group magnetic anisotropic permanent magnet - Google Patents

Abstract

PURPOSE:To obtain a permanent magnet having stable quality and excellent magnetic characteristics by changing a material into spraying powder, the grain size of an alloy, components and contents thereof are specified, and crystalline grain size thereof are specified and a main phase thereof consists of a tetragonal compound. CONSTITUTION:An alloy as a material is changed into spraying powder, which mainly comprises 8-30atom% R, 2-28atom% B and 42-90atom% Fe and has composite texture of 50mum-1mm. mean grain size and not less than 20mum crystalline grain size and a main phase thereof is composed of a tetragonal compound. The powder is high-frequency melted under a vacuum and an argon gas atmosphere, and a molten metal is lowered from a molten metal nozzle having 6mm.phi, and gas-atomized by argon gas at the velocity of flow less than the speed of sound and powdered. Collected powder is passed through a sieve as required, pulverized at the next stage, and molded in a magnetic field and sintered, thus manufacturing a magnetic anisotropic permanent magnet.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an alloy powder for magnetically anisotropic permanent magnets whose main components are R (where R is at least one rare earth element including Y), B, and Fe.

Recently, I'IBR alloys have been attracting attention as new permanent magnet alloys, and there are two known methods for producing I'IBR alloys, broadly divided into quenching and powder metallurgy.

The quenching method is a method similar to that used to generally produce amorphous alloys, such as melt spinning, rolling, and sputtering, and heat-treats the quenched ribbon as it is or the amorphous alloy. It has been reported that this material exhibits high coercive force.

However, since these are essentially isotropic and have fine crystal structures, they have not been able to provide excellent magnetic properties as magnetically anisotropic permanent magnets.

゛ Also, as a permanent magnet made by powder metallurgy, the applicant has previously developed Fe-BR based (R is at least one rare earth element including Y) magnetic material as a new high-performance permanent magnet that does not contain expensive Sm or 6. He proposed an anisotropic permanent magnet (patent application 145072/1982). Furthermore, Fe-B-
In order to improve the temperature characteristics of a permanent magnet made of an R-based magnetically anisotropic sintered body, a part of Fe is replaced with G, thereby raising the Curie point of the produced alloy by one point and improving the temperature characteristics of Fa. -We proposed a permanent magnet made of an anisotropic sintered body based on -ω-B-R (Japanese Patent Application No. 166663/1983).

The above novel Fe-B-R system, Fe-Co-8R system (R
is at least one rare earth element containing Y) The rare earth metal that is the starting material for producing a magnetic permanent magnet is generally a metal lump produced by a Ca reduction method or an electrolytic method, and this rare earth metal lump The novel permanent magnet described above is manufactured using, for example, the following steps.

■ As a starting material, electrolytic iron with an ITi degree of 99.9%, 8
A ferroboron alloy containing 19.4% and the remainder consisting of impurities such as Fe, N, and S5C, a rare earth metal with a purity of 99.7% or more, or an electrolytic metal with a purity of 99.9%.
is high-frequency melted, then cast into a water-cooled copper mold, coarsely pulverized to a throughput of 35 mesh using a stamp mill,
Next, using a ball mill, for example, 300 g of coarsely ground powder is wet-pulverized for 6 hours to form a fine powder of 3 to 10 ρ.
(1) Sintering at 1000°C to 1200°C for 1 hour After sintering in Ar, allow to cool.

■ Aging treatment, 500°C to 100°C, in Ar.

As mentioned above, the Fe-B-R based alloy powder for magnetically anisotropic permanent magnets is obtained by mechanically coarsely pulverizing and finely pulverizing an ingot of the desired composition, but the alloy powder for aqueous magnetically anisotropic permanent magnets is Powder is very difficult to crush, coarsely crushed powder tends to become flat, the load on the crusher is high and it is easy to wear out, and it is difficult to mass produce 1g of 35 mesh through powder required for the next fine crushing process. Moreover, there were problems such as poor yield of coarsely ground powder and poor grinding efficiency.

In order to solve this problem, the water-based permanent magnet alloy 1 (
Proposed a method of spontaneously disintegrating R2 by utilizing its occlusion property (Japanese Patent Application No. 58-1719094, Patent Application No. 58-22)
No. 7667), but the hydrogen-pulverized powder is easily oxidized and requires dehydrogenation treatment, making the process complicated.

The object of the present invention is to provide an alloy powder for magnetically anisotropic permanent magnets for producing 1 q of Fe-B-R permanent magnets that are inexpensive, stable, have IC quality, and have excellent magnetic properties. The purpose of this invention is to obtain an alloy powder for Fe-B-R permanent magnets, which is obtained by directly powdering molten gold and simplifying the agglomeration process and the coarse pulverization process.

J- That is, this invention includes R88 atoms to 30 atom% (however, R is at least one kind of rare earth elements including Y), B2 atom% to 28 atom%, Fe42 atom% to 90 atom%, is the main component, and the average particle size is 50. inc” 1 mm, a composite structure with a crystal grain size of 20 or more, and a rare earth/boron/iron based magnetically anisotropic permanent magnet alloy powder characterized in that the main phase is an atomized powder of a tetragonal compound. It is.

Generally, the method of powdering molten alloy by spraying is as follows:
■For alloys that are difficult to grind mechanically, such as rJli4 and cemented carbide, this method has been put into practical use industrially. Alloy systems are not the most suitable method because they are easy to mechanically crush, are extremely susceptible to oxidation, and do not provide excellent properties for use in magnetically anisotropic permanent magnets.

The present inventors discovered that R (where R is at least one rare earth element including Y), B, Fe! As a result of various studies on methods of producing an alloy powder for magnetically anisotropic permanent magnets mainly composed of By cooling and powdering at a cold FDL speed slow enough to avoid forming a fine composite structure less than vn, the atomized powder does not have poor magnetic properties, but it is further finely pulverized and then compacted in a magnetic field.

It has been discovered that the alloy powder for magnetically anisotropic sintered magnets produced by sintering has extremely poor properties.

This invention will be explained in detail below.

The method for producing rare earth/boron/iron magnetically anisotropic permanent magnet alloy powder according to the present invention consists of the steps of <melting → spraying → fine pulverization>, and includes the steps of <melting → ingot production → When compared with the process of coarse pulverization -> hydrogen pulverization -) dehydrogenation treatment -> fine pulverization, this is a greatly simplified production method.

Water-based alloys can be melted in a vacuum or in an inert gas, for example, by melting pure iron, ferroboron, rare earth iron alloys, or electrolytic cobalt as a starting raw material using high frequency, as shown in the examples, and melting it from the bottom of a crucible or After pouring the molten metal into the ladle, let the molten metal fall from the bottom of the ladle,
It is atomized with an inert gas such as argon gas and collected in a vacuum or in a chamber with a non-oxidizing fL atmosphere. At this time, if the atomized gas has a flow rate higher than the speed of sound or the molten metal flow is less than 3111n+φ. The average particle size is 50B.
If it is less than m, a fine composite structure will result, which is not preferable for use in magnetically anisotropic permanent magnets.

In addition, the collected powder is passed through a sieve and subjected to the next pulverization, if necessary, and then molded and sintered in a magnetic field to produce a magnetically anisotropic permanent magnet.

Here, if the obtained powder exceeds an average particle size of 1 mm,
It is difficult to finely pulverize the powder to a diameter of several f, and the coarse pulverization step is an intermediate step, which is undesirable because it causes a large amount of pulverization.The average particle size of the powder after spraying must be 50 ρ to 1 mm.

Magnetic anisotropic sintered magnets are made by orienting and molding powder that has been pulverized into 2-10 mm pieces in a magnetic field. ,
Since the orientation of the crystals is not aligned due to the orientation of the magnetic field, a sintered magnet with excellent magnetic anisotropy cannot be obtained. Therefore, 50
The composite structure of the powder with an average particle size of f~1 mm is at least 20 mm. It is necessary to have a crystal grain size of 50 μm or more, and in particular, when the crystal grain size is 50 μm or more, it is easy to become a finely ground single crystal, and the blend is perfect during magnetic field blending during press molding. This is most preferred since excellent magnetic properties can be obtained. Also, the cooling rate of the molten alloy is 10
-1 to b As the atomization method, the inert gas 71 to mize method has been described, but in addition to this method, the same effect can be obtained by a centrifugal atomization method in which a rotating electrode is rotated or a rotating disk is rotated.

However, in the production of the powder of this invention, the molten alloy is poured from the bottom of the crucible or ladle, so a clean powder without slag entrainment is obtained, and the molten alloy can be directly powdered in a non-oxidizing atmosphere. Therefore, compared to conventional mechanically pulverized powder or hydrogen pulverized powder, it is possible to obtain an alloy powder with a lower oxygen content. Among them, it is 0.2 wt% or less.

The reasons for limiting the composition of the rare earth/iron/boron based raw material alloy powder for magnetically anisotropic permanent magnets according to the present invention will be explained below.

The rare earth element R contained in the raw material alloy powder for permanent magnets of this invention is a rare earth element that includes yttrium (Y) and includes light rare earths and ten rare earths.

As the first metal, a light rare earth metal is sufficient, especially Nd.

Pr is preferred. Also, one type of R is usually sufficient, but in practice, a mixture of two or more types (Mitsushiko Metal, Didim, etc.) can be used for reasons such as convenience of availability.
Ss, Y, La, Ce, Gd, etc. are other R1, especially N
It can be used as a mixture with d, Pr, etc. Note that R in and does not have to be a pure rare earth element, and Zrv! is an industrially available element. , or may contain impurities that are unavoidable during manufacturing.

R (at least one rare earth element including Y) is an essential element in the above-mentioned novel permanent magnet, and when it is less than 8 at%, the crystal structure becomes a cubic structure that is the same as α-iron. Therefore, high magnetic properties, especially high coercive force, cannot be maintained, and when the concentration exceeds 30 at%, there are many R-rich nonmagnetic phases.
However, the residual magnetic flux density (Br) decreases, making it impossible to obtain a permanent magnet with superior characteristics. Therefore, the rare earth elements range from 88 atoms to 30 atomic percent.

B is an essential element in the above-mentioned permanent magnets, and if it is less than 2 atom%, it will form a rhombohedral structure and will not have a high coercive force (iHC), and if it exceeds 28 atom%, it will have a rhombohedral structure. ,
8-rich nonmagnetic phase increases, and the residual magnetic flux density (Br
') decreases, making it impossible to obtain an excellent permanent magnet.

Therefore, B is in the range of 2 atomic % to 28 atomic %.

``e is an essential element in the new permanent magnet of the above system, and if it is less than 42 at%, the residual magnetic flux density (Br) will drop, and if it exceeds 90 at%, high coercive force cannot be obtained, so fTe The content is 42 atomic % to 90 atomic %.

Furthermore, in the alloy powder for permanent magnets according to the present invention, F
Substituting a part of o with 6 can improve the temperature characteristics of the obtained magnet without impairing its magnetic properties, but if the Go substitution amount exceeds 50% of Fa, the magnetic properties will be adversely affected. is undesirable because it causes deterioration.

In addition, alloys containing the following additive elements and impurities mixed in from raw materials and manufacturing processes also have a tetragonal compound containing RlB and Fe as the main phase and exhibit superior magnetic properties.

Furthermore, at least one of the following additional elements is Fe −
It is added to B-R permanent magnets because it is effective in improving coercive force, etc., improving manufacturability, and reducing costs.

Tj 4.5 atomic% or less, Ni 4.5 atomic% or less,
■ 9.5 atomic% or less, Takashi 12.5 atomic% or less, T
a 10.5 atomic% or less, Cr 8.5 atomic% or less,
Mo 9.5 atomic% or less, W 9.5 atomic% or less, -
3.5 atomic% or less, M 9.5 atomic% 1'J, lower, S
b 2.5 atomic% or less, Ce 7 atomic% or less, ST
+ 3.5 atomic% or less, Zr 5.5 atomic% or less,
BL 5 atomic% or less, He 5.5 atomic% or less, SL 8 atomic% or less, Zarani, S 2.0 atomic% or less, C2 atomic% or less, Ca 8
atomic % or less, −8 atomic % or less, P 3.5 atomic % or less, 0 2 atomic % or less, etc.

In addition, H, L'L, Na, K, Be of 1 atomic % or less
, Sr, Ba, AQ, Zn +, NF,
&, Se, To, Pb.

The preferred composition of the permanent magnet alloy according to the present invention is when the main component of R is 50% or more of a light rare earth metal, R12 atomic % to 20y Y 1 atomic %, B44 atomic % to
This is a case in which the main components are 24 at. % Fe, 65 at. % to 82 at. % Fe, or 20 at. % or less of Co, and the total of the above additive elements or impurities is at most 5 at. %.

Examples according to the present invention will be shown below to clarify its effects.

Example 1 As a starting material, electrolytic iron with a purity of 99.9%, 819.4
Ferroboron alloy containing 90-% cation, with the remainder consisting of Fe and impurities such as /V, S5 C, etc.
-M alloy, 17tV & 19B -74F
These were high-frequency melted in a vacuum and argon gas atmosphere, and the molten metal was dropped from a 61nIIIφ molten metal nozzle and gas atomized with argon gas at a flow rate below the speed of sound to form a powder.

The resulting atomized powder had an oeffl of 1300 ppm and an average particle size of 1'20 μn.

According to XPA diffraction, the jN alloy powder has a-8,
7, c = 12.3, and the alloy powder had an average crystal grain size of 25 JAl and had a main phase of a tetragonal intermetallic compound that produced a sharp pattern.

Then, 3,000 particles collected from this sprayed powder were finely pulverized in a ball mill for 6 hours to obtain an alloy powder with an average particle size of 3.3.

Using this alloy powder, it was oriented in a magnetic field of 10 KOe, and 2
[Molded in a perpendicular magnetic field on wood, then molded in Ar at 1060°C.
Sintered under the conditions of ℃, 2 hours, and 650℃ in Ar
℃ for 1 hour to produce a permanent magnet.

The magnetic properties of permanent magnets are Sr = 11.9KG1 ■t]c = 13.0KOe.

(B)-1) max = 34.2M G Oe
.

a Hc = 11.0 KOe.

For comparison, an alloy of the same composition was inserted into a closed container,
Flow H2 gas for 10 minutes to replace it with air, 10k
G, hydrogen pulverized and treated with H2 gas pressure of J for 1 hour.
When I obtained coarsely ground powder with a mesh size of 5, the 02 opening was 2.
It was 230 ppm. Furthermore, dehydrogenation treatment 1! I! rear,
Finely pulverized for 3 hours using a ball mill to obtain an average particle size of 3.
Two batches of alloy powder were obtained.

The alloy powder obtained by this hydrogen pulverization was made into a permanent magnet under the same manufacturing conditions, and the magnetic V? When the properties were measured, Br = 12.
0KG1 1Llc = 12.8KOe, (B1-1) max =34.3MGOe, [J H
c = 10.8 KOe by 1 digit.

Example 2 As a starting material, electrolytic iron with a degree IIi degree of 99.9%, 819
．． f[1 boron alloy, Fe-M alloy containing 90% M, Fe-positive containing 67% positive Alloy, 99.7% pure circular metal, 99.7% pure electrolytic] Balt is used, 16m-INb IPr 9B-10Go
-63Fe was blended into a composition consisting of -63Fe, and these were melted at high frequency in a vacuum and argon gas atmosphere, and the molten metal was dropped from a 6 mm diameter molten metal nozzle, and the gas was pulverized by 71 to 100 ml of argon gas at a flow rate below the speed of sound. .

The resulting atomized powder had a Jfi of 950 ppm and an average particle size of 150.mn.

The obtained alloy powder had an average grain size of 35 and had a tetragonal compound as its main phase.

Then, 300 grams of this sprayed powder was pulverized in a ball mill for 6 hours to obtain an alloy powder with an average particle size of 3.1.

Using this alloy powder, it was oriented in a magnetic field of 10 KOe, and 2
At t4, orthogonal magnetic field molding was performed, and then 106 (
+'c, 2 hours, sintered in the strip f1, and further Arrl
A permanent magnet was produced by aging at 650°C for 1 hour.

Magnetic properties of permanent magnets (yo, Br=10.8KG.

+ Hc = 16.8KOe, (13t-l) maX = 28.6MGOe, n H
c = 10.6KOo.

For comparison, an alloy of the same composition was inserted into a closed container,
Let H2 gas flow in for 10 minutes and replace it with air, 1ok
Hydrogen pulverization was carried out under a H2 gas pressure of 1j, 4 for 1 hour to obtain a coarsely pulverized powder with a throughput of 35 mesh, and the amount of 02 was 1850 ppm. After rough dehydrogenation treatment, finely pulverized to 3rR using a ball mill to obtain an average particle size of 3.3.
A reverse alloy powder was obtained.

The alloy powder obtained by this hydrogen pulverization was made into a permanent magnet under the same manufacturing conditions, and its magnetic properties were measured, and it was found that 13r = 11.
0KG.

IHc’ = 15.7K Qa.

(BH) m’aX = 28.2MGOe.

e　Hc　=10.11<Oθ was obtained.

Example 3 As a starting material, electrolytic iron with a purity of 99.9%, El 19
, 4% with the remainder being Fe and impurities such as M, Si, and C, and an Fa-boron alloy containing 90% of porcelain.
These are melted at high frequency in a vacuum and argon gas atmosphere, and then melted through a molten metal nozzle with a diameter of 10 mm.
The molten metal was dropped and pulverized by argon gas at a flow rate of less than the speed of sound.

The amount of sprayed powder obtained was aooppm and the average particle size was 560Bm.

The obtained alloy powder had an average grain size of 65ρ and had a tetragonal compound as its main phase.

Next, 500(+) collected from the sprayed powder was pulverized for 1 hour in a vibrating mill to obtain an alloy powder with an average particle size of 2.82 ml.

Using this alloy powder, it is oriented in a magnetic field of 10 KOθ, and 2
At 162, orthogonal magnetic field molding was performed, and then in Ar, at 106
Sintered at 0°C for 2 hours, and then sintered at 65°C in Ar.
A permanent magnet was produced by aging at 0°C for 1 hour.

The magnetic properties of permanent magnets are B r = 12. ! il(Q.

＋! -1c = 13.2KOe, (BH) maX = 37.5M Gos, BHc
= 11.6) (Qe.

As is clear from Examples 1 to 3, the alloy powder according to the present invention has excellent quality as an alloy powder for rare earth/boron/iron magnetically anisotropic permanent magnets, and the powdering process is also very easy. It is very effective for industrial implementation.

Applicant: Sumitomo Special Metals Co., Ltd. Agent Push ET3 Ryo E1 Shuguchi

Claims (1)

[Scope of Claims] I R88 atoms to 30 atom% (wherein R is at least one kind of rare earth elements including Y), B 2 atom% to 2
8 at%, Fe 42 at% to 90 at%, and has a composite structure with an average particle size of 50 Jjm to 1 nm + and a crystal grain size of 20 - or more, and the main phase is a sprayed powder of a tetragonal compound. An alloy powder for rare earth, boron, and iron-based magnetically anisotropic permanent magnets.