JPS6091601A - Method for pulverization for rare earth-boron-iron permanent magnet alloy powder - Google Patents

Abstract

PURPOSE:To stabilize quality as well as to improve magnetic characteristics of the titled alloy powder by a mehtod wherein R, B and Fe of the prescribed atomic percentage are used as main ingredients, and the alloy powder of prescribed particles size is pulverized into the prescribed particle size at normal temperature together with the liquid phase hydrocarbon fluoride of the prescribed boiling point temperature. CONSTITUTION:10-30atom% R, 2-28atom% B and 65-82atom% Fe are used as main ingredients, they are pulverized in a short period, and the particle size of the alloy powder before pulverization is prescribed at 10 mesh-through in order to prevent the coexistence of coarse grains in the pulverized powder. Then, the above material is placed in a pulverizer together with the liquid phase hydrocarbon fluoride of the boiling point of 35 deg.C or above. Then, a wet pulverization is performed on the powder of 1-10mum in average particle size at normal temperature. Through these procedures, the alloy powder of stabilized quality can be obtained, and coersive force and the like can also be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an alloy powder for permanent magnetic white whose main components are [at least one rare earth element containing RG and LY], B, and Fe. This invention relates to the improvement of the wet grinding method in which the above-mentioned permanent magnetic alloy fine powder with excellent magnetic properties and stable quality is obtained.

Permanent magnetic materials are one of the extremely important electrical and electronic materials used in a wide range of fields, from various household appliances to peripheral terminal equipment for large computers. In recent years, with the demand for smaller electric and electronic devices and greater efficiency, permanent magnet materials are increasingly required to have higher performance.

Current representative permanent magnet materials are alnico, hard ferrite and rare earth Kobal 1~ magnets.

As the raw material situation for cobalt has become unstable in recent years, demand for alnico [i] containing 20 to 30 wt% cobalt has decreased.
Inexpensive hard ferrite, whose main component is iron oxide, has come to dominate magnet materials.

On the other hand, rare earth cobalt magnets have a power of 50 to 60W to Kobal 1.
t% and uses Sm, which is not contained in rare earth ores, it is very expensive, but it has much higher magnetic properties than other magnets, so it is mainly used as a small and high value-added magnet. It has become widely used in circuits.

Therefore, the present inventor first developed an Fe-B-R system (RL
! Y 'i *At least one rare earth element>
He proposed a permanent magnet (Japanese Patent Application No. 145072/1982).

Furthermore, in order to improve the temperature characteristics of permanent magnets made of Fe-B-R magnetically anisotropic sintered bodies, by substituting a part of Fe with G, the Curie point of the resulting alloy was increased by one point. Now, Fe-G with improved temperature characteristics.

-B - A permanent magnet made of an anisotropic sintered body was proposed (Japanese Patent Application No. 166663/1983).

The above novel Fe-BR system, Fa-Go-BR system ([
< is at least one kind of rare earth element containing Y) The rare earth metal that is the starting material for manufacturing a permanent magnet is generally a metal lump produced by the Cam base method or the electrolytic method, and this red earth metal lump is The novel permanent magnet described above is manufactured using, for example, the following steps.

■ As a starting material, electrolytic iron with a purity of 99.9%, 819
．． Fe/boron alloy containing 4% Fe and impurities such as # and S5C, rare earth metals with a purity of 99.7% or more, or electrolytic metals with a purity of 99.9% are melted by high frequency, and then Cast in a water-cooled copper mold, ■ Coarsely grind to 35 mesh through using a stamp mill, and then wet-pulverize, for example, 300 g of coarsely ground powder for 6 hours using a ball mill to make a fine powder of 3 to 100 g. ■ Magnetic field ( 10KOe) and molded (1.5td
(1) Sintering, sintering in Ar for 1 hour at 1000°C to 1200°C, and then allowing to cool.

■ Aging treatment, 500°C to 1000°C, k medium.

As mentioned above, the alloy powder for permanent magnets is obtained by mechanically pulverizing and wet pulverizing an ingot having a desired composition.
In this wet pulverization method, the coarsely pulverized powder of 35 mesh is mixed with methanol.

Pour the mixture into a crusher such as a ball mill or attritor along with a solvent such as ethanol, isoamyl alcohol, or trichloroethane, and rotate the rotary blades inside the crusher or the machine together with the steel balls to reduce the rot to 10% or less. There were various problems with the grinding process and the magnetic properties of the resulting permanent magnet.

However, the above-mentioned solvents, methanol and ethanol, are highly hygroscopic, and the finely ground powder is easily oxidized.
Lichloroethane easily decomposes in the air or in the water contained in the pulverized powder and reacts with the powder. Furthermore, since the above solvent is toxic and dangerous, it is necessary to pay close attention to its handling, which may cause operational problems. On the other hand, permanent magnets obtained by pressing and sintering finely pulverized powder using such solvents have had problems in that their magnetic properties have deteriorated or caused variations. .

The purpose of this invention is to provide a wet pulverization method for producing rare earth, boron, and iron alloy powder for permanent magnets that has stable quality and excellent magnetic properties. Intended as a fine grinding method.

In this invention, R (wherein R is at least one kind of rare earth elements including Y) 10 at% to 30 at%, B 2 at% to 28 at%, Fe 65 at% to 8
An alloy powder containing 2 atomic % as a main component and having a particle size of 10 mesh through is charged into a pulverizer together with a fluorinated hydrocarbon whose boiling point is 35°C or higher and is liquid at room temperature.
This is a method for pulverizing a rare earth/boron/iron alloy powder for permanent magnets, which is characterized by pulverizing it into oI powder.

This invention was developed after studying various solvents to be used for wet pulverization of alloys for permanent magnets whose main components are R, B, and F'e, and found that fluorinated hydrocarbons, which have a boiling point of 35°C or higher and are liquid at room temperature, are optimal. It has been found that fluorinated hydrocarbons include trichlorotrifluoroethane, perfluorotributylamine, tetrachlorodifluoroethane, penzotrifluoride, perfluorobenzene, perfluoromethyldecalin, etc. Hydrogen has a boiling point of 35
Anything below ℃ will evaporate when used as a solvent, so
It needs to have a boiling point of 35°C or higher, and it needs to be liquid at room temperature to perform wet pulverization.In addition, in this invention, the particle size of the alloy powder before pulverization is set to 10 mesh through. Coarse particles that exceed mesh throughput require a long time to be pulverized, and there is a risk that coarse particles may be mixed in the bed after pulverization.

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

The rare earth element (1) contained in the raw material alloy powder for permanent magnet 6 of this invention is a rare element that includes yttrium (Y) and also includes light nth and m8 earths.

When t<iL, a light rare earth is sufficient, especially Nd.

l) p is very scary. In addition, one of the standard sizes is sufficient, but in practical use-1, a mixture of two or more types (Mitsuhmetal, didymium, etc.) may be used for reasons such as convenience of availability.Sm, Y, La, Ce, Gd.

etc. can be used as a 1:2 mixture with others, especially Nd, Pr, etc. J3, this first sentence does not have to be a pure rare earth element, and may contain impurities that are unavoidable in production within an industrially available range.

1 (at least one rare earth element that Ω is Y) is
As the alloy coarsely pulverized powder for manufacturing the new above-mentioned permanent magnet, it is an essential element, and if it is not vortexed at 10 atomic %, it has high magnetic properties, especially high coercive horns, and if it exceeds 30 atomic %, The residual magnetic flux density (Br) decreases, making it impossible to obtain a permanent magnet with excellent characteristics. Therefore, the rare earth element is defined as being in a range of 10 atomic % to 30 atomic %.

B is an essential element for the coarsely pulverized alloy powder used to manufacture the new above-mentioned permanent magnets, and if it is less than 2 atomic %, a high coercive force (+t-l) cannot be obtained, and if it exceeds 28 atomic %, B cannot be obtained. , the residual magnetic flux density (Br) decreases, making it impossible to obtain an excellent permanent magnet.Therefore, B is set in the range of 2 at.% to 28 at.%.

"e is an essential element for the alloy coarsely ground powder used to manufacture the new above-mentioned permanent magnets, but if it is less than 5 atomic %, the residual magnetic flux density (Br ) will decrease, and if it exceeds 82 atomic %,
Since high coercive force cannot be obtained, Fe is 65 atomic % to 82 atomic %.
Limited to atomic percent.

In addition, the reason why part of Fe is replaced with CO is that it has the effect of improving the temperature characteristics of the permanent magnet, and CO
When it exceeds 50% of Fe, a high coercive horn is obtained.
, it is not possible to obtain a permanent magnet with a slight deviation.

For Mac and Co, the upper limit is 50%.

In the coarsely pulverized alloy powder of this invention, an excellent permanent magnet having both high residual magnetic flux density and strong coercive force can be obtained. In order to
~2 G11i f%, "C68 atomic % to 80 atomic % is very good.

Further, the alloy coarsely ground powder according to the present invention is composed of RlR, Fe
In addition, the presence of unavoidable impurities in industrial production can be excluded, but a part of B can be replaced by 4.0 at% or less of C13, 5 at% of P, 2.5 at% or less of S, 3 .515N, child%
By substituting at least one of the following Cus in an amount of 4.0 atomic % or less, it is possible to improve the manufacturability and lower the price of the magnetic alloy.

Further, the above R, B, Fe alloy or Co is 8% 1, B, Fe alloy is added with 9.5 atomic % or less of An, 4.5 atomic % or less of T1.9.
．． V of 5 atomic % or less, Or of 8.5 IfA atomic % or less, 8
．． Mn not more than 0 atom% Bi not more than 15 atom%, 12.5
Nb below atomic %, Ta below 10.5 atomic %, 9
．． Mo of 5 atomic % or less, W of 9.5 atomic % or less.

2.5 atomic % or less of 811, 7 atomic % or less of Ge, 35
8 atomic % or less, 5.5 atomic % or more Zr, 5.5
By adding at least one kind of Hf at atomic % or less, it becomes possible to increase the coercive force of the permanent magnet alloy.

It is essential that the main crystalline phase is a tetragonal one in order to obtain a fine and uniform alloy powder.

The particle size of the alloy fine powder according to this invention has an average particle size of 10J.
If it exceeds 7111, it will not be possible to obtain excellent magnetic properties, especially high coercive force, when producing a permanent magnet, and if the average particle size is less than 1 µm, the permanent magnet production process, lining, press forming, sintering, aging, etc. will be difficult. There is significant oxidation during the treatment process,
Because excellent magnetic properties cannot be obtained, the average particle size is 1 to 10.
1A11 alloy fine powder is most desirable.

The magnetically anisotropic permanent magnet alloy obtained using the alloy fine powder for permanent magnets according to the present invention has a coercive force + HC≧I K
Oe, residual magnetic flux density Br > 4KG, maximum energy 1 (BH) ma, x is equal to or higher than hard ferrite, and in the most preferable composition range, (t3 fi
) max≧10MGOe, the maximum value is 25MGO
Reach θ or more.

Further, the composition of the alloy fine powder according to the present invention is R10 atomic % to 3oIIl atomic %, B22 atomic % to 28 atomic %, G45
The magnetically anisotropic permanent magnet alloy deposited on the platform containing 65 at% to 82 at% Fe exhibits magnetic properties similar to those of the above magnet alloy, and has a temperature coefficient of residual magnetic flux density of 0.1.
%/''C or less, and excellent characteristics can be obtained.

In addition, when the main component of R in the powder of alloy V) is a light rare earth metal that accounts for 50% or more, R12 atomic % to 20 atomic %,
El 41Gi %~24 at%, θ 65 at%~
In the case of 82 atomic %, or even Co5 atomic % to 45 atomic %
It shows the most outstanding magnetic properties when containing atomic percent,
Especially when the light rare earth metal is ceramic, (B H) max
reaches its maximum value of 33M G Oe g.

Further, the alloy fine powder according to the present invention can be press-molded in the absence of a magnetic field to produce an isotropic permanent magnet.

Examples will be described below.

Example 1 As a starting material, electrolytic iron with a purity of 99.9%, 819.4
A ferroboron alloy with a purity of 99.7% or more is melted by high frequency, and the balance is made up of impurities such as Fe and C.
After that, it was cast in a water-cooled copper mold and made of 15 porcelain 8B77Fe (at
%) was obtained.

This ingot was coarsely ground to a throughput of 35 mesh by mechanical grinding. Next, 300 (l) collected from the coarsely ground powder
2 steel balls with an outer diameter of 10 mm were placed in a ball mill with dimensions of outer diameter 150 mm x inner diameter 120IIll x length 150 mm.
．． Using 600 cc of trichloro-trifluoroethane as a solvent, fine pulverization was carried out at 100 revolutions for 5.5 hours to obtain an alloy powder with an average particle size of 3.3 μm.

Using this alloy powder, it is oriented in a magnetic field of 10 KOθ, and 2
Pressure molded at tJ, then 1100°C for 1 hour.

The magnet was sintered under the following conditions and further subjected to aging treatment at 600° C. for 1 hour in Ar to produce a permanent magnet. The magnetic properties of the obtained permanent magnet were measured and are shown in Table 1.

For comparison, a permanent magnet was prepared from an ingot of the same composition using the method of this invention described above except that methanol aoocc was used as the solvent during pulverization, and the magnetic properties were similarly measured. Table 1 shows the measurement results.

Example 2 As a starting material, electrolytic iron with t11i100.9%, E1
19.4% and the remainder consists of impurities such as Fe and C] XU boron alloy, Minami metal and Mi metal with a purity of 99.7% or more are high-frequency melted, then cast in a water-cooled copper mold,
51ml, 5Dy 7B76.5Fe (at%) composition: 9 to 1 ingot/:.

This ingot was coarsely ground to a throughput of 35 mesh by b1 mechanical grinding. Next, 300g collected from the coarsely ground powder
was charged into a ball mill with an outer diameter of 15010 Ill x west longitude 120 nun x length 150 mm together with steel balls 2 and 8 k with an outer diameter of 10 mm, and 70 Linate F (, -72 (trade name, manufactured by Sumitomo 3M Co., Ltd.) as a solvent. 3S
) Using 600cc, 5.5R at rotation speed of 100r
Fine pulverization was performed in between to obtain an alloy powder with an average particle size of 3.35 μm.

Using this alloy powder, it was oriented in a magnetic field of 10 KOe, and 2
4. Pressure molded at 1100°C for 1 hour.

The magnet was sintered under the following conditions and further subjected to aging treatment at 600° C. for 1 hour in Ar to produce a permanent magnet. The magnetic properties of the obtained permanent magnet were measured and are shown in Table 2.

For comparison, an ingot with the same composition was mixed with 1.
1. A permanent magnet was prepared under the same conditions as the method of this invention described above except that 600 cc of trichloroethane was used, and the magnetic properties were similarly measured, and the measurement results are shown in Table 2.

Example 3 As a starting material, electrolytic iron with a purity of 99.9%, 919.4
A ferroboron alloy with a purity of 99.7% or more is melted by high frequency, and the remainder is made up of impurities such as Fe and C.
Then cast in a water-cooled copper mold, 20Pr 8B 72F
1 ki of an ingot having a composition of e (at%) was obtained.

This ingot was mechanically crushed to a roughness of 35 mesh through. Next, 300g collected from the coarsely ground powder was heated to an outer diameter of 150n+n+X, an inner diameter of 120mm, and a length of 150m.
A steel ball with an outer diameter of 10 mm was placed in a ball mill of 2.8 mm in diameter, and finely pulverized for 5.5 mm at a rotation speed of 1100 rp using perfluor A rottribudylamine GOOcc as a solvent. (1'l of alloy powder with an average grain size of 3.1 gn).

Using this alloy powder, it was oriented in a magnetic field of 10 KOθ, and 2
Pressure molded at t4, then 1100'C for 1 hour.

Sintered under the following conditions, and then subjected to Di! treatment at 600°C for one cycle in Ar! A permanent magnet was produced. The magnetic properties of the obtained permanent magnet were measured and are shown in Table 3.

For comparison, a permanent magnet was prepared from an ingot of the same composition under the same conditions as the method of this invention described above, except that 600 cc of iso-noamyl alcohol was used as the solvent during pulverization, and the magnetic properties were similarly measured. As is clear from the results in Tables 1 to 33, permanent magnets using the fine powder obtained by the pulverization method of the present invention have magnetic properties. Moreover, if the magnetic properties are uniform, there will be very little variation in magnetic properties, which is extremely effective in industrial production.

Table 1 Table 2 Table 3

Claims (1)

[Claims] IR (however, 1 (1) is one type of rare earth element containing Y > 10 at% to 30 at%, B 2 at% to
An alloy powder whose main components are 28 at% Fe and 65 at% to 82 at% Fe is charged into a grinder together with a liquid fluorinated hydrocarbon with a boiling point of 35 °C or above and a temperature above 35 °C, and the average particle size is 1
A method for pulverizing rare earth/boron/iron alloy powder for permanent magnets, which is characterized by finely crushing the powder into a powder with a diameter of ~10ρ.