JPS6037602B2 - Permanent magnet material and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention primarily relates to a permanent magnet material containing CeMM and cobalt, and a method for producing the same.

Many materials of this type have already been described in the literature. For example, D. V. Ratnam and M. G.
Day. Wens is a member of the River PConf. Proc.
18 American Institute of Physics
, New York, 1974, showed the characteristics of Mitsushi metal-cobalt magnets. Ratnam and Wells here report individual magnets with energy products up to lamG and coercivities up to 14 KOe, but these magnets exhibit only depletion curves with no significant rectangularity. "Selmismetal" refers to a light rare earth separated from ore.

For example, E. V. Kleber and B.
Loue is a technology of Scandium, Yttrium and the Rare Earth Metals.
qMm and the RareEareh Meta
ls), Pergermon Press
Press), New York 1
On page 96310, bastnesite and monazite are rare.
The following shows that it contains the following percentages: Bastnesite Monazite La 30 38 Ce 50 48.5 Pr 4 3.6 Nd 14 8.8 Sm l 0.5 In other words, the composition of Selmitsimetal is The most important components cerium, lanthanum, neodymium and praseodymium are at least 45 to 5 and 20 to 40 depending on the raw material ore.
, 5-14, 0-5 at.%.

This is certainly the reason why it is difficult to produce samarium magnets with good properties and reproducible values with Selmitsimetal or with Selmitsimetal additives. Therefore, it is an object of the present invention to provide a permanent magnet containing Celmissi metal that not only has an excellent rectangular demagnetization curve, but also has an energy product of about 1 aMq or more and a coercive force of about 1 aM or more, which can be manufactured reproducibly and economically. It's about getting the materials.

For this purpose, according to the invention, the material has the general formula: (CeMM, ~SEX), -ySmyC*Sat〇. 2 [here 0.05 x 0.5: OSy mi 0.25,
SE stands for one of the rare earths cerium, lanthanum, neodymium and praseodymium], where the cermitsimetal is approximately CeQW8NdyPr6 [where 0.
45<Q<0.55, 0.20<8<0.40, 0.0
5<y<0.1fu 0.0 6<0.05 and Q+
30y+6x1], and the atomic percent ratio of cerium and lanthanum, neodymium or praseodymium in the product magnet material is 0.20/0-55 μLa/Ce.
or 3 Ce or 0.40/0.4 ft or 0.05/0.55 3 Nd/Ce or Nd/
Ce30.15/0.45 or Pr/Ce30.05
/0.45 is solved by satisfying the condition.

Since the composition range of the raw material Celmissi metal is defined as above, for example,
The ratio is 0.20/0.55 (minimum value)<La/Ce<0
．． 40/0.45 (maximum value), i.e. greater than the minimum value 0.20/0.55 and the maximum value 0.40
/0.45.

However, according to the present invention, by using, for example, Ce as SE, the ratio of I/Ce of the product magnet material can be reduced to this maximum value of 0.
．． 40/0.45 or more, and as an SE, for example, Ce
When using , this ratio must be less than or equal to the minimum value 0.20/0.55. The same applies to the addition of neodymium or praseodymium. One of nearly pure cerium, lanthanum, neodymium and praseodymium as SE
By additionally adding +80y+6 in such an amount to 1, that is, highly pure Selmitsushi metal, the content of impurities, especially iron, in Selmitsushi metal is further reduced, and as will be described later. The magnetic properties of the product magnet material are improved depending on the added elements. To produce such materials, the raw material alloy and optionally sintering additives are charged to a mill in coarsely ground form, ground under protective gas to a powder with a particle size of several degrees, and then heated in a magnetic field of about 50 KOe. 1035 to 10
It is advantageous to sinter at temperatures between 45°C and heat treat at temperatures above 30,000°C.

The heat treatment can advantageously be carried out in two ways.

According to one method, the permanent magnet material is 950-10200
Heat treatment is performed at a temperature of 300 to 600 degrees Celsius, especially about 350 degrees Celsius, for 30 to 40 minutes, and in some cases up to 60 minutes.

However, as a second method, it is also possible to place the permanent magnet material after heat treatment in a zone at a low temperature, for example about 300 DEG C., and to cool it to room temperature after a maximum of 1 hour, especially after 15 minutes. Magnet materials produced in this way are invariably characterized by a high energy product, a large coercive force and an approximately rectangular demagnetization curve. In particular, cermiscimetal-cobalt-containing materials show a surprising improvement in coercive force. In particular, the excess amount of neodymium is 0.
~45 atomic % materials exhibit even improved remanence. The material can be formed from a raw material alloy in a protective gas atmosphere, for example under helium or argon.

It is desirable to use a freezing additive that mixes with the raw alloy.

Sintering additives include rare earths, especially Ce, La, Nd, and P.
An alloy with wt.% r or Sm6 and 40 wt.% Co is suitable, which is about 10-14 wt.% relative to the total mass of the mixture.
occupies It is particularly advantageous to grind this mixture of tin-coated additive and starting alloy in coarsely ground form in a jet grinder. Next, embodiments of the present invention will be described with reference to the drawings.

The composition of the raw material for the permanent magnet material to be manufactured, measured with an accuracy of approximately 1% using an X-ray basic spectrometer, is 53.7 at% Ce, 30.2 at% France, 12.0 at% Nd, and Pr.
4.0 atomic % Selmitushi metal, each purity 9
9.9% Sm, Ce, La, Nd and Pr and 99.99% purity cobalt were used. All alloys were prepared in a medium frequency furnace under a protective gas of argon in a boron oxide rubbo with a charge of 120 min each.
It was dissolved at 20. The molten brittle alloy was then ground to particles with a diameter smaller than 0.5 side and then ground in a jet grinder to particles with a particle size of 2.5 to 4 mm. The powder was compacted into a cylindrical sample with suitable pressure, oriented in a magnetic field of about 50 KOe, isostatically compacted at 60 atmospheres, and then sintered at 1035-1045 qo for at least half an hour.
A subsequent heat treatment, which will be detailed later, made it possible to further significantly improve the magnetic properties of the produced material. A dawning additive consisting of an alloy of weight % Sm6 and weight % Co4 was added to the ground raw material alloy before sintering.

The weight of this sintering additive is 10% of the total weight of the compacted body to be sintered.
It varied between ~14%. However, in the case of suitable raw material alloys and solidification in an oxygen-free atmosphere, it is also conceivable to produce sintered magnets with additives. In addition to Sm-Co alloy, SE60-Co40 alloy (here SE is Ce, L
Also suitable as sintering additives are light rare metals of the form A, Pr, Nd). In addition to melting from the elements, powdered raw material alloys were also produced by mixing ground CeMMC and SEC alloys and subsequent milling.
The ground sintering additive was added to the similarly ground raw material alloy, and the mixture was ground into powder using a jet grinder. Four series of alloys CeMM, -XCeXCeMM, -X melted by this method
LaXC et CeMM, -xPrxC Takumi and CeMM,
-xNdxC Takumi (CeMM, SEX), -ySm
yC Takumi±〇. 2 [SE NiCe, La, Nd, Pr
A permanent magnet material having a composition of: 0<x<0.5 and OSy 0.25 was produced.

The demagnetization curve of these materials was determined by a vibration magnetometer at 50 KOe.
Measured at maximum magnetic field. Measurement results for representative materials are summarized in the table and Figures 1-5.

Table: Composition of the molten alloy and hard magnetic properties of the permanent magnet material produced therefrom using Sm6 with O40 sintering additives. Song 7L et al. Nail 2NdM2oPro.
By o4, Alloys 1-13 can also be expressed by the following formula: 'a} Alloys 1-3 (Ceh4M), MCexC [x=0:0.15 and 0.30]'b' Alloys 4-6 ( CeMM), -XPrXC Hiro [x:0.10:0.20 and 0.30]
．． 10] {d} Alloy 9-13 (CeMM), ★NdX
Based on measurements of permanent magnet materials made from C-Taku [xni 0.05; 0.10; The increase in the cerium content in the missmetal (alloy 1, the permanent magnet material made from it is denoted by 1 in Figures 1-4) initially acts to increase the coercive force (additional cerium content x = 0.1
However, as the cerium content further increases, the coercive force, remanence decreases, and the rectangularity of the MH curve deteriorates, so according to the table, the formula (CeMM), -xC
The proportion of cerium in the cermisci metal, which corresponds to an exC value of 0.05 to 0.25, of about 55 to 65 atom % has an advantageous effect on the magnetic properties.

Composition (CeMM, Cex), -ySmyC$[0.0
5<x<0.25 and OSy mi. The permanent magnetic material of [25] therefore exhibits surprisingly good magnetic properties. Table (alloy 1
, 4, 5, 6) and Fig. 2, the increase in lanthanum content is due to the increase in the lanthanum content in the Celmissi metal alloy (alloy 1) with no additional lanthanum content.
It is clear that this is accompanied by an increase in coercive force from JHc of 7.4 KOe to JHc of 12.7K for a total lanthanum content of 51.1 at%.

The residual magnetism BR remains unchanged within the measurement accuracy, as do the rectangularity of the magnetization curve and the energy product (BH) max. From this result, the formula (CeMM) rx
It is confirmed that a lanthanum content of 0.40 to 0.65, which corresponds to a value of 0.15 to 0.50, significantly improves the coercive force. According to the table (alloys 1, 7, 8) the formula (CeMM)
, -xPrxC An increase in the praseodymium content to 5 to 10 atomic %, which corresponds to an x value of 0.03 to 0.06, has an advantageous effect on the magnetic properties.

As is clear from the table (alloys 1, 9 to 13) and FIG. 4, increasing the amount of neodymium affects the maximum increase in coercive force.

An increase from 12 atomic % in Celmissimetal Alloy 1 without additional neodymium to 20.8 atomic % in Alloy 10, for example, increases the JHc to 7. The remanent magnetism also increases as the rotation temperature increases from OE to 16.1K. When the neodymium content increases above 35 at.% (alloy 12), the coercive force JHc decreases appreciably and reaches a value of only 4.7 KOe at 56.0 at.%. However, the residual magnetism of this composition is 8. Become a mackerel G. Therefore, as is clear from Fig. 5, the improvement in the magnetic properties of the cermiscimetal-cobalt alloy is achieved by the equation (CeMM
), ~12 corresponding to the X value of 0 to 0.45 in NdxC et al.
Occurs with neodymium amounts of ~50 atom %. The material of the invention, like all other SEC-containing, especially CeMM-containing, permanent magnetic materials, can have its magnetic properties greatly improved by heat treatment at appropriate temperatures and subsequent heat treatment.

The optimum annealing temperature was determined using a CeMMC method magnet.

The magnets were made using 8-1 wt.% crystallization additives consisting of 60 wt.% Sm and 8-1 wt.% Co4. In this case, CeMMC Kou alloy and Sm6 O4 river alloy were ground separately in a jet crusher and mixed for 1/2 hour, resulting in 60KOe
The sample was oriented in a magnetic field of 10 mm and compressed isostatically at a pressure of 10 pi atmospheres. For mixtures containing additives 8, 10, 14 and 1 tablet cloud content 1015<Ts>1055qo
sintered at various temperatures in the range of . It has been found that the density p and the remanence always increase with the coupling temperature. On the other hand, the energy product exhibits a pronounced maximum as shown in FIG. 6, which decreases with increasing amount of sintering additive and corresponds approximately to the optimum sintering temperature. This experiment revealed that a dawning temperature of 1035-104yo is favorable for all selmismetal-containing cobalt magnets. The magnet material is first heated to 95% by subsequent heat treatment.
Heated to a temperature of 0-1020 oo.

The holding time is 20 minutes to 50 hours. After heating the sample was quenched in a liquid such as liquid nitrogen, glycerin or other oily organic liquid such as silicone oil. Cooling under a low-temperature protective gas atmosphere, such as argon or nitrogen, has also proven to be very suitable. successive 3
The magnetic properties were further improved by tempering at 00 to 600 qC for 10 to 3 minutes. The improvement of permanent magnet properties is shown in Fig. 7 with CeM magnet. 8Smo. This will be explained using the demagnetization curve of a magnet with a composition of 2C Takumi.

The improvement of the permanent magnet material by the heat treatment described above is of course also conceivable for all other magnets containing cobalt. The curve shown as a solid line in Figure 7 is Ts = 1040
The demagnetization curve after sintering at q0 is shown. The chain line shows the demagnetization curve after heating at 980°C and steepening in liquid nitrogen.
After tempering at 50°C and 400oC. From this curve, the coercive force increases by 2.23% due to heating and rapid cooling.
It is clear that the subsequent tempering treatment further increases the JHc by 1. Other experiments show that heating requires 98
A temperature of 0°C and 10°C was shown to be optimal.

The upper limit of coercivity is in this case independent of temperature. In addition to the increase in JHc to 2.3 sounds, the demagnetization curve approaches a rectangular shape and the residual magnetism BR increases when the heating time is 6 hours or more. Furthermore, the cooling rate was found to be a very important parameter for this method. In this case, quenching with nitrogen is particularly desirable. That is J
This is because a significant increase in Hc value occurs and the energy product increases with heating time exceeding 6 hours (16 in the example in Figure 7).
force) to 17MG 戊). The temperature and time of the tempering process are important. The optimum improvement in magnetic properties is achieved at a tempering temperature of 350°C.
This is achieved with a burn-back time of 30 to 4 minutes.

[Brief explanation of the drawing]

Figure 1 Excess amount of cerium x is 0, 0.15 and 0.3
Alloys 1, 2 with composition CeMM, -xCexC
Figure 2 shows the demagnetization curve of 3 when the lanthanum excess x is 0 and 0.
．． 1, 0.2 and 03 with the composition CeMM,-xL
Demagnetization curves of axC raw alloys 1, 4, 5, and 6, Figure 3 shows alloys 1, 7, 8 of composition CeMM, ~ PrxC with praseodymium excess x of 0, 0.05, and 0.1. Figure 4 shows the demagnetization curves for neodymium excesses of 0, 0.25, 0.
Composition CeMM which is 1, 0.15 0.3 and 0.5
．． -xNdxC wide alloys 1, 9, 10, 11, 12, 1
Figure 5 shows the relationship between the neodymium content and coercive force JHc and remanence BR of the CeMM-containing permanent magnet material, and Figure 6 shows the relationship between the sintering temperature Ts and the energy product (BH) of the CeMM-containing alloy. ) max relationship, Figure 7 shows the relationship between heating at 980oC for 20 minutes, cooling with liquid nitrogen, and approx.
CeMMo.00, 350, and 40000 were competitively returned with an average particle size of about 4〃. 8S kite. FIG. 2 is a diagram showing an extinction curve of a permanent magnet material having a composition of 2C Takumi. Figure 6, Figure 2, Figure 3, Figure 4, Figure 5, Figure 7.

Claims (1)

[Claims] 1. A permanent magnet material mainly containing CeMM and cobalt, the material having the general formula: (CeMM) and cobalt.
eMM_1_-_xSE_x)_1_-_ySm_yC
o_5±_0_. _2 [0.05<x<0.5 here;
0<y<0.25 and SE stands for one of the rare earths cerium, lanthanum, neodymium and praseodymium), where the cermitsimetal is approximately CeαLa
βNdγPrδ [where 0.45<α<0.55;0.
20<β<0.40;0.05<γ<0.15;0.0
0<δ<0.05 and α+β+γ+δ■1], and the atomic percent ratio of cerium to lanthanum, neodymium or praseodymium in the product magnet material is 0.
20/0.55≧La/Ce or La/Ce≧0.
40/0.45 or 0.05/0.55≧Nd/Ce or Nd/
Ce≧0.15/0.45 or Pr/Ce≧0.05
A permanent magnetic material characterized by satisfying the condition of /0.45. 2. In the method for producing a permanent magnet material according to claim 1, the raw material alloy and optionally the sintering additive are charged into a mill in a coarsely pulverized form, and then heated under a protective gas to reduce the particle size to several μm.
The powder formed is oriented in a magnetic field of about 50 KOe and isostatically compressed into a compact, 103
A method for producing a permanent magnet material, characterized by sintering at 5 to 1045°C and heat treating at a temperature exceeding 300°C.