JPH04322405A - Rare earth permanent magnet - Google Patents

Abstract

PURPOSE:To obtain a magnet having high magnetic characteristic by stabilizing a structure of ThMn12 through substitution of R of RFe12 compounds with a third element M without substitution of Fe. CONSTITUTION:A rare earth permanent magnet has a structure of alloy expressed by (R1-XMX) (Fe1-YCOY)Z (where, R is a kind or two kinds or more of rare earth elements mainly composed of Y, Th and Sm; M is a kind or two kinds of elements selected from Zr, Hf, Bi, Sn, In, Pb; 0.01<=X<=0.4, 0 <=Y<=0.5, 10<=Z<=13). The main phase thereof has the Body-centered tetragonal crystal ThMn12 structure and M atom is substituted by R atom.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a new rare earth permanent magnet having a ThMn12 structure and having high magnetic properties.

0002

BACKGROUND OF THE INVENTION Among body-centered tetragonal ThMn12 type rare earth-transition metal compounds, a ternary compound with a high Fe content was previously invented by the present inventors (Patent Application No. 1983-
84723, 61-84724, 61-84725, 6
2-82398, 62-82399, 62-10821
8, 62-108219, 62-211194, 62-
224764). However, ThMn12-type RFe1
2 compounds do not exist, and high F is achieved only by introducing a 3rd element.
The compound in the e region is stabilized. Typical stoichiometric ratios include SmTiFe11, SmV2Fe10,
SmCr2Fe10, SmMo2Fe10, SmWFe
No. 11, SmSi2Fe10, SmReFe11, etc. are known. Of course, it is not limited to Sm,
Compounds exist that have the same stoichiometry for almost all rare earth elements (R). T in such a high Fe region
A compound with hMn12 structure is called R(MFe)12
When expressed as , most of these compounds are
It has a Curie temperature (Tc) of 300° C. or higher, and also has a high saturation magnetic flux density (Ms) due to the high content of Fe. Among them, Sm-based compounds have a significantly high anisotropic magnetic field and are optimal as permanent magnet materials, and in fact, high coercive forces of 10 KOe or more have been obtained in liquid super-quenched magnets. Nd2Fe14B is the only other known ternary compound in such a high Fe region.

[0003] The R(MFe)12 compound has very high magnetic properties as mentioned above, but it
) replaces Fe with a non-magnetic element, such as Nd2F
Comparing e14B and SmTiFe11 compounds, Fe
Although the atomic percentages of the atoms are almost the same, the magnitude of saturation magnetization is considerably lower in the latter. Therefore, R(MFe)1
Efforts are being continued to increase the saturation magnetization by lowering the ratio of the third element M in the 2-system as much as possible, preferably approaching zero. However, no success has been achieved in lowering the ratio of M element further than in RTiFe11 compounds and the like.

0004

[Problems to be Solved by the Invention] From the above points of view, the present invention does not replace Fe in RFe12-based compounds, but substitutes R with a third element M to stabilize the ThMn12 structure and improve magnetic properties. This is what we are trying to achieve.

[0005]

[Means for solving the problem] The present inventors have developed R(MF
e) 12 As a result of repeated research on the role of M element in compounds, instead of replacing Fe with a third element M,
It was discovered that the Th2Mn12 structure could be stabilized by substituting R, and after thorough consideration of various conditions, the present invention was completed.
YCoY)Z (However, R is one or more rare earth elements mainly consisting of Y, Th and Sm, and M is Zr.
, Hf, Bi, Sn, In, Pb, 0.01≦X≦0.4, 0≦
Y ≦ 0.5, 10 ≦ Z ≦ 13), the main phase thereof is a body-centered tetragonal ThMn12 structure, and M atoms substitute R atoms. It is.

The present invention will be explained in detail below. When the lattice of the M element is slightly larger than that of Fe, it is thought that the M element replaces Fe, expands the lattice, and stabilizes the ThMn12 structure. It is known that when the M element is vanadium V, which has a wide solid solubility limit, the lattice shrinks as the V amount decreases. In other words, without the M element, the lattice becomes small, and the space in which Fe atoms should originally enter becomes too small. But also, if the M atom is much larger than the Fe atom,
Since the lattice must be expanded significantly, ThMn
12 structure cannot be stabilized. For this reason, R( M
It is thought that the elements that stabilize the Fe)12 compound are limited and the amount of substitution is also limited within a narrow range.

[0007] From the above considerations, instead of replacing Fe with a larger atom, conversely, by replacing R with a smaller atom, it is possible to provide a spatial margin that allows the Fe atom to enter the lattice. It is considered that the ThMn12 structure can be stabilized by this. As a substituent atom at the R site, Zr, Hf, etc., which are smaller than general rare earth elements and too large to replace the Fe site, cause Th.
It was found that the Mn12 structure can be stabilized.

The amount X of the additive element M is 0.01 or more, 0
．． 4 or less is preferable. If it is less than 0.01, the ThMn12 structure cannot be stabilized, and the R2Fe17 phase and F
If the amount of R to be substituted is 0.
If the amount is more than 4, the magnetic anisotropy of the RFe12 magnetic alloy mainly depends on the R element, making it impossible to obtain satisfactory magnetic properties as a magnet material. It has been experimentally found that the M substituent element preferably has a size between that of a rare earth element and a Fe atom, and is preferably an element larger than a Ti atom. M elements are Zr, Hf, Bi, Sn, I
n,Pb can stabilize the ThMn12 structure.

[0009] Fe atoms can be replaced with Co atoms, and Co substitution improves the Curie temperature and improves the temperature stability of magnetic properties. Further, although the saturation magnetization increases slightly due to Co substitution, the crystal magnetic anisotropy decreases on the contrary, so the amount of Co substitution is preferably Y≦0.5 or less. The amount of transition metal is as follows: When Z<10, R2Fe17 is stabilized, and when Z>
In No. 13, Fe becomes the main phase and the ThMn12 structure is not stabilized, so it is necessary to fall within this range.

[0010] Here, R is applied to one or more elements selected from the group consisting of rare earth elements mainly consisting of Y, Th, and Sm.

Magnetization of the compounds of the invention is possible by various means. Typical means include sintered magnets or bonded magnetization. The obtained alloy is finely pulverized using a jet mill or the like to produce a magnet alloy powder. For this fine pulverization, a liquid super-quenching method, a mechanical alloying method, a gas atomization method, or the like may be used. For sintered magnets, magnet alloy powder is molded while being oriented in a magnetic field, and this is
Sintering is performed at a temperature range of 1,000 to 1,300°C, followed by aging treatment at a temperature of 500 to 900°C. For a bonded magnet, a magnet alloy powder may be mixed with an organic binder, oriented in a magnetic field, and then the organic binder may be hardened to form a bonded magnet.

0012

[Examples] Hereinafter, embodiments of the present invention will be explained in detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. (Example 1) 99% purity Sm metal, 99.9% purity
The additive metal elements such as Fe, Co and Zr are shown in Table 1 (
Alloy Nos. 2 to 9) were weighed, high-frequency melting was performed in an inert gas, and the molten metal was cooled in a copper mold. After coarsely pulverizing the ingot, use a jet mill using N2 gas to grind the ingot to 3 to 5 μm.
It was finely pulverized to a diameter. The fine powder was oriented in a static magnetic field of 15 KOe and press-molded at a pressure of 1 ton/cm2, and then the molded body was placed in an inert gas at 1.0
Sintering is carried out at a temperature of 50 to 1,250 °C for 1 to 2 hours,
Subsequently, heat treatment was performed in a temperature range of 500 to 900°C for 1 hour or more, and then quenched. Magnetic properties of the sintered body iH
Table 1 shows the results of measuring c using a self-recording magnetometer. As a comparative example, an alloy without M added was alloy No. 1 and are also listed in Table 1. As shown in Table 1, when no M element such as Zr is added, the ThMn12 structure cannot be formed and the material separates into the 2-17 phase of the Th2Zn17 structure and the Fe and Co phases. Satisfactory magnetic properties have not been obtained. It is also seen that when the amount of M element exceeds the R site substitution rate of 10%, the magnetic properties deteriorate rapidly.

[0013]

[Table 1]

[0014]

[Effects of the Invention] According to the present invention, T
The R(Fe,Co)12-based magnetic material with the hMn12 structure can be stabilized by substituting rare earth sites with Zr, Hf, etc., and it also solves the problem of low saturation magnetic flux density, which is the problem with conventional 1-12-based magnetic materials. Since there is no longer a need to dilute the transition metal sites that mainly play a role in this with non-magnetic metals such as Ti, we have not only been able to overcome this problem, but also made it possible to use it to create magnets with high characteristics. . Also this 1-12
Since the system magnet has Fe as its main component, there is no need to use a large amount of expensive Co, and it has great advantages in terms of resources, supply stability, and cost, and has extremely high industrial utility value.

Claims (1)

[Claims] Claim 1: The alloy composition has the formula (R1-X MX) (Fe
1-YCoY)Z (However, R is Y, Th and Sm
one or more rare earth elements mainly consisting of 1 or more, M selected from Zr, Hf, Bi, Sn, In, and Pb;
species or two or more elements, 0.01≦X≦0.4, 0
≦Y≦0.5, 10≦Z≦13), the main phase thereof has a body-centered tetragonal ThMn12 structure, and M atoms substitute R atoms.