JPS63118029A - Manufacture of permanent magnet alloy - Google Patents

Abstract

PURPOSE:To obtain stable magnet characteristics, by uniformizing mixing by means of wet blending in a process for manufacturing a permanent magnet consisting of a rare earth-Co intermetallic compound by means of a reduction- diffusion process. CONSTITUTION:A permanent magnet consisting of an intermetallic compound represented by RM5 or R2M17 is manufactured, where R means one or more elements among rare earth metals composed principally of Ce, Sm, and Pr and M means a combination of one or more elements among Co, Fe, and Cu (elements A) and one or more elements among Zr, Hf, Nb, and Ti (elements B). In order to manufacture the above permanent magnet, a powder of the oxides of R, a powder of pure metals or alloys of the elements A, and a powder of pure metals or alloys of the elements B are subjected to wet blending in the presence of mixing auxiliaries, followed by drying. Subsequently, one or more reducing agents among Ca, CaH2, and Mg are mixed with the above powder mixture, and the resulting mixture is heated at 1,000-1,300 deg.C in a vacuum, inert, or reducing atmosphere to undergo reduction-diffusion reaction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing a permanent magnet alloy made of a rare earth cobalt-based intermetallic compound using a reduction diffusion method.

[Conventional technology]

Rare earth cobalt permanent magnets are manufactured by high-frequency melting using pure metals or alloys of rare earth metals and transition metals as raw materials, and then mold casting.

The obtained alloy ingot is generally pulverized to adjust the particle size, then formed in a magnetic field, sintered and then heat treated (115 series), or solution treatment followed by aging treatment (2/17 series). be.

However, since rare earth metals are generally expensive, the above-mentioned melting method requires high raw material costs.

This is a major factor that increases manufacturing costs. Therefore, in order to improve the above-mentioned drawbacks of the dissolution method, an inexpensive (
C
A reduction-diffusion method has been proposed in which alloying is performed with O, Fe, and other metal components through a diffusion reaction. (For example, Tokuko Sho 48-
No. 7296, No. 53-16798, No. 55-3057
5 and No. 55-27602).

[Problem that the invention seeks to solve]

However, in the conventional reduction-diffusion method, uniform mixing cannot be achieved due to differences in particle size distribution, specific gravity, shape, etc. of the raw materials to be mixed, so there have been problems such as difficulty in obtaining stable magnetic properties. That is, the rare earth oxide powder used as the raw material is a cohesive fine powder with an average particle size of several μm. on the other hand.

The average particle size of pure metal or alloy powder of transition metals such as Co, Fe, and Cu is from several tens of micrometers to several hundred micrometers. Therefore, it has been difficult to uniformly mix these raw material powders having significantly different particle size distributions.

An object of the present invention is to solve the problems of the prior art described above, and to provide a novel reduction-diffusion method that achieves uniform mixing through wet mixing and provides stable magnetic properties.

[Means for solving problems]

The method for manufacturing the permanent magnet alloy of the present invention is R(Ce').

An oxide powder of one or more rare earth metals such as Sm and Pr) and a pure metal of element A (one or more transition metals such as Co, Fc, and Cu).

or alloy powder, and pure metal or alloy or oxide powder of element B (one or more of Zr, HL, Nb, TJ, etc.) at a predetermined composition (RM).

It is characterized in that after blending with R2M□7), wet mixing is carried out in the presence of a mixing aid. Namely.

Formula RM s or R2M F Here, R is one or more rare earth metals mainly consisting of Ce, 5LIl, and Pr, M is Co, Fe, Cu, that is, one or more of the elements Zr, Hf, Nb, In a method for producing a permanent magnet alloy made of an intermetallic compound represented by a combination of one or more elements of Ti, that is, B elements.

(b) Wet-mix the oxide powder of R, the pure metal or alloy powder of element A, and the pure metal or alloy or oxide powder of element B in the presence of a mixing aid, and then dry it. ) Next, one or more reducing agents selected from Ca, CaH2, and Mg are added to the mixed powder.

(c) The resulting mixture is heated in vacuum or in an atmosphere (inert or reducing) at a degree of fi of 1000 to 1300°C to undergo a reduction-diffusion reaction.

With the above configuration, the non-uniformity of mixing due to differences in powder properties such as particle size distribution, specific gravity, shape, etc. of raw materials can be greatly reduced.

Examples of usable mixing aids include water, alcohols (ethanol, isopropyl alcohol, ethers (ethyl ether, ethylene oxide), aldehydes (n-butyraldehyde, glyoxal), ketones (acetone, methyl ethyl ketone), chain carbon M (L yuic acid,
tartaric acid), esters (methyl acetate, isoamyl acetate),
Examples include chain nitrogen compounds (isobutylamine, triethylamine), aromatic compounds (benzene, toluene, phenol, octahalogenated hydrocarbons (trichlorethylene, CG triethane), etc. The mixing operation can be carried out using known equipment such as a V-type mixer. After wet mixing, the mixed slurry is filtered using a centrifugal separator, etc. to remove the aid, and then heated and dried in a vacuum.After that, the amount of reducing agent (Ca , CaH2, Mg) and further mixed.Then, this mixed powder is set in a reaction container, and A r , Ne , He
, in an inert atmosphere such as K r +Xe, or a reducing atmosphere such as H2, or in vacuum (l O-2 to l O-'
Torr) in a temperature range of 1,000 to 1,300°C to perform a reduction-diffusion reaction. In this step, the rare earth metal oxide and the metal oxide are reduced by a reducing agent and alloyed by interdiffusion to form a cake-like reaction composition. Next, this is thrown into water for hydration treatment, and then pickled.

The desired alloy powder is obtained by washing with water, followed by drying and pulverization. By using the present alloy powder, a rare earth cobalt-based permanent magnet alloy having stable magnetic properties with little variation can be obtained. For example, in the R2M□7 series, after filling the alloy powder into a mold, compression molding is performed by applying a pressure of 2 to LOton/a# in a magnetic field of 5 to 20 KOe.
The obtained molded body is heated in an inert gas atmosphere such as Ar, Ne, He, Kr, or Xe, or in a hydrogen gas atmosphere, or in a vacuum (1
0-2~10-'Torr) 1150-1250'
The sintered body is then sintered at a temperature of 1100 to 125 C.
Solution treatment is carried out by holding at a temperature of 0'C (71°C) for 0.5 to 4 hours, then quenching by pouring into a cooling medium such as oil or water, and then at a temperature of 800 to 950 degrees Celsius for 0.5 to 3 hours. After holding, it is held at 0°3-b for 0.5-3 hours for aging treatment.

The present invention will be explained below using Examples and Comparative Examples, but the scope of the present invention is not limited thereby.

〔Example〕

Example 1 Sm, O with an average particle size (air permeation method) of 1.01 μm.

1058.3g of powder and 150 mesh under C
After putting 1587.5 g of Sm powder into a V-type mixer, 20. After adding toluene in an amount sufficient to immerse the Co powder (5I1120 in the V-type mixer, the amount sufficient to slurry the Co powder in toluene) and mixing for 30 minutes, remove toluene using a centrifuge. Ta. Next 80
℃, dried in a vacuum atmosphere of 1X10-'' Torr to obtain a toluene-treated S m , O , Go mixed powder. 474.5 g of Ca under 6 meshes was added to this and mixed again in a V-shape. A raw material mixture was obtained by mixing for 30 minutes in a machine.Then, this mixture was poured into a reaction vessel.

A reduction-diffusion reaction was carried out at 1165° C. for 2 hours in an Ar atmosphere. After that, the reaction cake was poured into water for 2 hours, and after repeated washing, the reaction cake was washed for lh and H within the range of P H = 2 to 5.
Pickling with Cl, then pH=6.5-7
Neutralize until
Vacuum drying in orr.

A 115-series rare earth cobalt powder (average particle size: 4.9 μm) was obtained through vibration mill pulverization. This was press-molded in a magnetic field of 10 KOe (transverse magnetic field) at a pressure of 4°C on/-, and then sintered in a H2 atmosphere with a 1110" CX 4 h strip. The obtained sintered body was After holding at 950℃ for 1 hour
The mixture was slowly cooled to 800'C at a rate of 3°C/min, and sand-cooled at a water temperature of 1°C. Table 1 shows the average one-turn and standard deviation values of the stone characteristics for the 100 water-immersed magnets obtained. It can be seen that according to the manufacturing method of the present invention, variations are small and high air flow characteristics can be obtained.

Example 2 A 115-series rare earth cobalt magnet was prepared in the same manner as in Example 1, except that water was used as the mixing aid, and the magnetic properties were evaluated (see Table 1).

Comparative example I Sm, ○, 1058.3g, Co1.587.5g.

A raw material mixture was obtained by mixing 474.5 g of Ca in a V-type mixer for 30 minutes without using a mixing aid.

After the reduction-diffusion reaction, 115
We created rare earth cobalt magnets and evaluated their magnetic properties (
(See Table 1).

Example 3 Each powder of Sm, Off 3020 g, Co50' 20 g, Fe 1400 g with 150 mesh under, Cu 1022 g with 100 mesh under, and Zrl 80 g with 100 mesh under were each accurately weighed.
After putting it into a mold mixer, adding ethanol as a mixing aid and mixing for 30 minutes.

Ethanol was removed using a centrifuge.

5I112 was then vacuum dried and treated with ethanol.
0. , Co, Fe, Cu, and Zr mixed powder was obtained.

Add 1,354 g of Ca to this and use the V-type mixer again for 30 g.
A raw material mixture was obtained by mixing for a minute. This was set in a reaction container, and a reduction-diffusion reaction was carried out at 1150° C. for 2 hours in an Ar atmosphere. Next, the reaction cake was poured into water for 2 hours, washed repeatedly, and then washed for 1 hour within the range of P H = 2 to 5.
Pickling with HCl, then pH=6.5-7
Neutralize until dry, dry and crush.

2/17 rare earth cobalt powder (average particle size 3.7゜μm
) was obtained. Next, this alloy powder was press-molded in a magnetic field of 10 KOe (horizontal magnetic field) at a pressure of 4 ton/cj, and then H
Sintering was carried out in a 2 atmosphere under conditions of 1.200″C x 4h.

The obtained sintered body was held at 1180'C for 4 hours, then oil-cooled, then heated to 850°C, held at that temperature for 4 hours, and then slowly cooled to 400°C at a rate of 0.6'C/a+in. and held there for 3 hours. About 100 permanent magnets obtained.

Table 1 shows the average values and standard deviation values of the magnet characteristics.

Example 4 A 2/17 rare earth cobalt magnet was prepared in the same manner as in Example 3, except that acetone was used as the mixing aid, and the magnetic properties were evaluated. Table 1 shows the results.

Comparative example 2 5m2033020g, Co5020g, Fe1400
g, Cu1022g, Zr180g.

A 2/17 rare earth cobalt magnet was prepared in the same manner as in Example 3, except that 1354 g of Ca was mixed in a V-type mixer for 30 minutes without using a mixing aid to form a raw material mixture, and the magnetic properties were determined. evaluated (see Table 1).

Example 5 In the same method as in Example 3, 350 g of Hf and 95 g of Ti were used instead of 100 mesh under Zr.
Table 2 shows the magnetic properties of the permanent magnet obtained by adding 84 g of Nbl.

Table 2 in the margin below [Effects of the invention] As described above, the reduction-diffusion method according to the present invention greatly contributes to the production of magnets with stable quality and less variation in megalith properties compared to the conventional reduction-diffusion method. There is.

Claims (1)

[Claims] Formula RM_5 or R_2M_1_7 where R is one or more rare earth metals mainly consisting of Ce, Sm, and Pr, and M is one or more of Co, Fe, and Cu (i.e., element A) and Zr. , Hf, Nb, and Ti (i.e., element B) in a method for producing a permanent magnetic alloy consisting of an intermetallic compound represented by a combination of one or more of the following: (a) oxide powder of R and pure metal or alloy powder of element A; and a pure metal, alloy, or oxide powder of element B are wet-mixed in the presence of a mixing aid, and then dried; It is characterized by additionally mixing at least one reducing agent, and (c) heating the resulting mixture in a vacuum or atmosphere (inert or reducing) in a temperature range of 1000 to 1300°C to undergo a reduction-diffusion reaction. A method for producing a permanent magnet alloy.