JP2660917B2 - Rare earth magnet manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is based on rare earth metals (R), transition metals (T) and boron (B) represented by Nd.Fe.B permanent magnets. The present invention relates to a method for producing an R ₂ T ₁₄ B-based intermetallic compound magnet, and more particularly to improvement of magnetic properties of a magnet using a liquid quenched amorphous alloy powder. [Prior Art] Conventional methods for producing R / Fe / B magnets are roughly classified into two methods. One is that when the molten alloy is rapidly quenched, the fine crystal grains (approx.
After adjusting the quenching rate so as to include the super-quenched microcrystallized ribbon so as to include a polymer resin, it can be combined with a polymer resin or uniaxially applied at high temperature. There is a manufacturing method of a liquid quenching type obtained by pressing. On the other hand, the R ₂ T ₁₄ B alloy ingot obtained by melting is finely pulverized and formed in a magnetic field, and R ₂ T ₁₄ B has crystals in the most anisotropic direction. There is a manufacturing method of a sintered mold manufactured by using the method. This manufacturing method is more suitable for obtaining high magnet properties than the former. Incidentally, the manufacturing process of the sintered magnet generally proceeds in the order of melting, grinding, orientation in a magnetic field, compression molding, sintering, and aging of the raw material alloy. Melting is usually performed in a vacuum or inert atmosphere such as arc or high-frequency heating, and a raw ingot is cast into a water-cooled copper mold. The pulverization is divided into coarse pulverization and fine pulverization, and the coarse pulverization is performed by a jaw crusher, an iron mortar, a disk mill, a roll mill, or the like. Fine pulverization is performed by a ball mill, a vibration mill, a jet mill, or the like. Orientation and compression molding in a magnetic field is customary to take place at the same time using a mold, wherein as R ₂ T ₁₇ B system crystal C axis is aligned to show a large magnetic anisotropy, R ₂ T ₁₇ B type powder particles are formed. That is, by orienting the C-plane of the crystal to a higher degree, a high-performance anisotropic magnet can be realized. Sintering is usually
It is performed in an inert atmosphere at a temperature of 1000 to 1150 ° C.
Aging contributes to the improvement of _I H _C, subjected by the need, typically 6
It is performed at a temperature near 00 ° C. [Problems to be Solved by the Invention] As described above, the conventional liquid quenching magnet is a polycrystalline body in which the molding powder particles composed of R ₂ T ₁₄ B-based crystal particles do not have anisotropy. Therefore, it is difficult to make anisotropic by molding in a magnetic field or the like, and high magnet properties have not been obtained. Therefore, when trying to obtain high magnet properties,
The powder was deformed under high pressure uniaxially at high temperature to give anisotropy. In this manufacturing method, the equipment is large and expensive, and is industrially disadvantageous. In general, the alloy powder used for liquid quenching magnets is sprayed in a high-speed rotating Fe or Cu roll on an alloy melted by high-frequency heating in an inert atmosphere such as Ar.
It is obtained by roughly pulverizing an alloy ribbon of about 104 μm. By controlling the number of revolutions of this roll, the cooling rate of the melted alloy can be controlled. However, rapid cooling containing fine crystal grains of about 0.05 μm, which has been considered to provide good magnet properties in the past, has been achieved. The alloy ribbon can be obtained only in a very limited range with a roll frequency of about 20 m / sec, and the quenched alloy ribbon is pulverized according to the purpose and magnetized. According to this manufacturing method, since the anisotropy of the magnet is extremely low, high magnet properties cannot be obtained industrially. If you leave shown for reference, in the hot press method, the closest method to the present _{invention, Br7.9KG, I H C 16KOe.} (BH) max. 13M
・ Approximately G · Oe. Therefore, the technical problem of the present invention is to solve the above-mentioned drawbacks by R.
An object of the present invention is to provide a method for producing a rare-earth magnet having simple and inexpensive anisotropy with respect to the use of a T / B-based amorphous alloy powder and having excellent industrial magnet properties. [Means for Solving the Problems] According to the present invention, R ₂ T containing Nd, Fe, B as a main component
_In a method of manufacturing a _14B- based magnet (where R represents Y and a rare earth element and T represents a transition metal) by using an amorphous RTB alloy, an amorphous RT R ₂ T ₁₇ alloy crystal powder is mixed with B-based alloy powder in an amount of 0 to 90 wt.
A method for producing a rare earth magnet characterized by performing sintering is obtained. Further, according to the present invention, there is provided a method for producing a rare earth magnet, wherein the average pulverized particle size of the magnetic field forming powder is 5 μm or less (excluding 0). That is, the present invention need not contain R ₂ T ₁₄ B system crystal particles in a molding powder, R ₂ T
_This is based on the discovery that the anisotropy of the _14B- based sintered body is achieved. In other words, after forming a molding powder obtained by mixing an R ₂ T ₁₇ crystal alloy powder and an R • T • B amorphous alloy powder in a magnetic field, sintering to obtain an R ₂ T ₁₄ B alloy. Thus, an anisotropic R ₂ T ₁₄ B-based sintered magnet is obtained. Therefore, according to the present invention, even when an RTB-based amorphous alloy is used as a raw material, high magnet properties can be obtained, sinterability is improved, and a reduction in sintering temperature can be realized. It is extremely useful in industry. Here, R ₂ T ₁₇ for amorphous RTB alloy powder is used.
The mixing ratio of the system crystal powder is 0 to 90 wt.% (Not including 0), and the upper limit is set to 90 wt.%.
-This is because it is extremely difficult to produce a TB alloy, and in addition, the magnet properties are reduced, and the practical value related to the mixing ratio is reduced. The average particle size of these molding powders is 5 μm or less (0
Is not included). The reason why the average pulverized particle size is set to 5 μm or less is that when the average pulverized particle size is less than 5 μm, a clear improvement in magnet properties is recognized. This improvement in magnet properties is due to the fact that the crystal C plane of the R ₂ T ₁₄ B crystal grains in the sintered body is more highly oriented in the direction orthogonal to the magnetic field orientation direction, and the diffusion of atoms is also improved.
This is because the ability to form R ₂ T ₁₄ B crystals is also improved. Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. Example 1 Nd with a purity of 97 wt.% (The remainder is another rare earth element mainly composed of Ce.Pr), B with a purity of 99.5 wt.%, And electrolytic iron were used.
Nd ₂ Fe _17- based ingot with 23.3 wt.% Fe and 76.7 wt.% Fe
Is 32.0 to 95.8 wt.%, B is 1.0 to 8.3 wt.% And the balance is Fe Nd
-Six types of Fe.B-based ingots were obtained by high-frequency heating in an argon atmosphere. Next, of these ingots, the Nd ₂ Fe _17- based ingot was kept at 1250 ° C. for 5 hours, and then kept at 1150 ° C. for 20 hours.
The precipitated α-Fe phase particles were eliminated to obtain a Nd ₂ Fe ₁₇ ingot. On the other hand, using an Nd-Fe-B-based ingot, after re-melting by high-frequency heating in an Ar atmosphere, a peripheral speed of about 100 m / sec
A liquid quenched amorphous alloy with a width of about 1 mm and a thickness of about 10 μm was obtained by spraying onto a Cu roll and using the single roll method. After coarsely pulverizing these Nd ₂ Fe ₁₇ ingots and six kinds of Nd-Fe-B amorphous alloys, the weighed composition was Nd32.0wt.%, B1.0w
%, Nd ₂ Fe ₁₇ alloy powder 0,10,30,5
After being mixed at 0,70,88 wt.%, The mixture was finely pulverized using a ball mill to an average particle size of about 2.5 µm. This powder is placed in a magnetic field of 20 KOe for 1 to
Molded at a pressure of n / cm ² . Next, the molded body was heated in vacuum at 200 ° C./hr to 1060 ° C., kept at 1060 ° C. for 1 hour, kept in Ar for 3 hours, and rapidly cooled. Next, this sintered body is heated at a temperature of 450 ° C. to 750 ° C. in an Ar atmosphere at 50 ° C.
Aged at ° C intervals. A magnetic field of about 30 KOe was applied to the sintered body to measure magnet properties. FIG. 1 shows the highest magnet characteristic values obtained with these samples having a mixing ratio of Nd ₂ Fe ₁₇ . Compared to the sample containing only the amorphous R, Fe, and B raw materials, the magnet characteristics (Br) were clear in the range where the Nd ₂ Fe ₁₇ raw material was mixed in the range of 0 to 90 wt.% (Excluding 0 and 90 being an extrapolated value). . (BH) _max ). Example 2 Cerium dymium comprising 5% by weight of Ce, 15% by weight of Pr, and the balance Nd (other rare earth elements were included as Nd), boron and electrolytic iron were used. And R
R ₂ Fe _17- based ingot with 23.5 wt.% And 76.5 wt.% Fe
After obtaining an R • Fe • B-based ingot of 76.0 wt.%, B of 5.0 wt.% And the balance of Fe, the R ₂ Fe _17- based ingot is heat-treated,
・ Fe ・ B system ingot was quenched by liquid and made amorphous alloy. Then, after coarse grinding these alloys, 80 wt the R ₂ Fe ₁₇ powder.
%, R, Fe, B type amorphous powder was mixed at 20 wt.%, And the average crushed particles were adjusted to 1, 2, 4, 7 μm using a ball mill, and then magnetic field molded. After maintaining this in a vacuum at 1040 ° C. for 1 hour, Ar
The medium was kept for 3 hours and quenched. Next, it was aged at 650 ° C. for 1 hour. FIG. 2 shows the magnet characteristics of this sintered body. As the crushed particle size becomes finer, the magnet properties are improved. The effect is remarkable in a region where the average crushed particle size is 5 μm or less. Example 3 Nd having a purity of 97 wt.% (The remainder being other rare earth elements mainly composed of Ce and Pr), boron, electrolytic iron, electrolytic cobalt and aluminum was used. % And (Fe ₇₇ · C ₂₀ · Al ₃ ) 76.7 wt.% Nd ₂ T ₁₇ series ingot, and Nd 34.0 wt.% And B 1.0 wt.% (Fe ₇₇ · Co ₂₀ · A
l ₃ ) is the remaining Nd / TB-based ingot and Nd is 59.0 wt.%
With B being 3.3 wt.% And (Fe ₇₇ · Co ₂₀ · Al ₃ ) the balance Nd · T
・ After obtaining the B-based ingot, the Nd ₂ T _17- based ingot was heat-treated, and the Nd · T · B-based ingot was quenched by liquid to obtain an amorphous alloy. Next, after coarsely pulverizing each, Nd34.0wt.% Nd
B type amorphous alloy is used alone, Nd ₂ T ₁₇ alloy and Nd 59wt.%
Nd-TB-based amorphous alloys with a weighing composition of Nd 34.0 wt.
1.0 wt.% After _{(Fe 77 · Co 20 · Al} 3) were mixed at a ratio of as 7 to 3 comprising the remainder, mean particle system with a ball mill of about 2
It was pulverized to μm. Thereafter, sintering, aging, and measurement of magnet properties were performed in the same manner as in Example 1. Table 1 shows the results. As a result, the sample mixed with Nd ₂ T ₁₇ ingot shows significantly higher magnet properties. As shown in the above embodiments, in a method of manufacturing an R ₂ T ₁₄ B-based magnet by using an amorphous RTB-based alloy, 1) an amorphous RTB-based alloy powder On the other hand, R ₂ T ₁₇ alloy powder is mixed in an amount of 0 to 90 wt.% (Excluding 0), and then molded and sintered in a magnetic field. 2) The average pulverized particle size of the molding powder of the item 1) is 5 μm or less (excluding 0). Thereby, the anisotropy of the sintered magnet is improved, and the improvement of the magnet properties can be achieved. In the above embodiment, <(Nd · Fe) + (Nd · Fe · B)>
System, <(CePrNdFe) + (CePrNdFeB)>
System, <(Nd.Fe.Co.Al) + (Nd.Fe.Co.Al.B)>
Although only the system was described, part of Nd was replaced with Y and other rare earth elements such as Gd, Dy, Tb, Ho, etc., and part of Fe was replaced with other transition metals such as Mn, Cr, Ni, etc. Or part of B is Si, C
The composition of the magnet alloy is Nd, Fe, B
Is a part of the main component.
If R ₂ T ₁₄ B typified by d ₂ Fe ₁₄ B contributes to magnetism, it can be easily presumed that the effects of the present invention can be sufficiently expected. Moreover, it is not necessary R ₂ T ₁₇ alloy raw material is not all R ₂ T ₁₇ crystals can be readily inferred that the improvement in the magnetic properties is involved in the space factor. [Effects of the Invention] As described above, according to the present invention, the R, T, and B-based amorphous alloy powder, which has been difficult to make
By mixing ₂ T ₁₇ alloy crystal powder, it can be performed easily and inexpensively anisotropy of, moreover, it is possible to improve the magnetic properties.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows the mixing amount (wt.%) Of Nd ₂ Fe ₁₇ in Example 1.
Properties of the Nd ₂ Fe ₁₄ B sintered magnet in the direction of the forming magnetic field (B
r, _I H _C , (BH) _max ), and FIG. 2 shows the average crushed particle size of the molding powder in Example 2 and the Nd ₂ Fe ₁₄ B-based sintered magnet in the molding magnetic field direction. magnetic properties (Br, _I H _C, is a correlation diagram between (BH) _max.

Claims (1)

(57) [Claims] R ₂ T ₁₄ B-based magnet containing Nd, Fe, and B as main components (where R represents Y and a rare earth element, and T represents a transition metal)
And a process for producing by the use of amorphous R · T · B type alloy, amorphous R · T · B based alloy powder to, 0~90wt.% Of R ₂ T ₁₇ alloy crystal powder (0 (Not including)
A method for producing a rare earth magnet, which comprises forming a powder for forming a magnetic field, and then forming and sintering in a magnetic field. 2. 2. The method for manufacturing a rare earth magnet according to claim 1, wherein the average particle size of the magnetic field forming powder is 5 μm.
A method for producing a rare earth magnet, characterized by the following (not including 0).