JPH04322406A - Rare earth permanent magnet - Google Patents

Abstract

PURPOSE:To obtain a magnet having high magnetic characteristic by stabilizing- ThMn12 structure through simultaneous substitution of Fe and R sites of RFe12 compounds with third elements M1, M2. CONSTITUTION:A rare earth permanent magnet has a structure of alloy expressed by (R1-XM1X) [(Fe1-YCOY)1-Z M2Z]W (where, R is a kind or two kinds or more of rare earth elements mainly composed of Y, Th and Sm; M1 is a kind or two kinds or more of the elements selected from Zr, Hf, Bi, Sn, In, Pb; M2 is a kind or two kinds or more of the elements selected from Ti, V, Cr, Mn, Mo, W, Nb, Ta, Si, Al; 0.01<=X<=0.4, 0.1<=Y<=0.5, 0.01<=Z<=0.3, 10<=W<=13). The main phase thereof has the Body-centered tetragonal crystal ThMn12 structure and R atom is substituted with M1 atom, while Fe or Co atom with M2 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 aims to improve magnetic properties by reducing the amount of substitution with the third element in RFe12-based compounds and stabilizing the ThMn12 structure while maintaining large saturation magnetization. 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 the M element in compounds, we found that if we replace R with the third element M1 and replace Fe with M2, we can reduce the total amount of the third element and achieve Th2M.
It was discovered that the n12 structure could be stabilized, and the present invention was completed after thorough consideration of various conditions, and the alloy composition is based on the formula
(R1-X M1X) [(Fe1-YCoY)1-ZM
2Z]W (However, R is one or more rare earth elements mainly consisting of Y, Th and Sm, M1 is Zr,
One or more elements selected from Hf, Bi, Sn, In, Pb, M2 is Ti, V, Cr, Mn, M
One or more elements selected from o, W, Nb, Ta, Si, Al, 0.01≦X≦0.4, 0
．． 1≦Y≦0.5, 0.01≦Z≦0.3, 10≦W
≦13), the main phase of which is body-centered tetragonal ThMn1
2 structure, and the M1 atom replaces the R atom, and the M2 atom replaces the F atom.
The gist thereof is a rare earth permanent magnet characterized by substitution of e or Co atoms. .

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.

From the above considerations, by replacing the Fe site with a larger atom to expand the lattice, or replacing the R site with a smaller atom to create a gap, T
It is thought that the hMn12 structure can be stabilized. As the R-site substitution element M1, one or more selected from Zr, Hf, Bi, Sn, In, and Pb, which have an atomic radius smaller than that of general rare earth elements and are too large to replace the Fe site. The elements are suitable. Regarding the substitution element M2 at the Fe site, Ti, which is slightly larger than Fe,
, V, Cr Mn, Mo, W, Nb, Ta, Si, Al
One or more elements selected from are preferred. It has been found that the effects of both the substitution with a larger atom at the Fe site and the substitution with a smaller atom at the R site work simultaneously, resulting in stabilization even if the amount of each substitution is reduced.

The amount X of the R-site substitution element M1 is 0.0
1 or more and 0.4 or less, preferably Fe site substitution element M
The amount Z of 2 is preferably 0.01 or more and 0.3 or less. M
If one element is less than 0.01 and the M2 element is less than 0.01, the ThMn12 structure cannot be stabilized, and R2
It separates into Fe17 phase and Fe phase. Also, M1
If the amount is more than 0.4, 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. Furthermore, when the M2 element also exceeds 0.3, the saturation magnetization mainly changes to F.
Since it depends on the amount of e atoms, the magnetic properties deteriorate.

[0009] ≦Z ≦0.3, 10≦W ≦1
3Fe atoms can be replaced with Co atoms, and Co substitution improves the Curie temperature and improves the temperature stability of magnetic properties. Furthermore, although the saturation magnetization increases slightly due to Co substitution, the magnetocrystalline anisotropy decreases, so the Co substitution amount Y is preferably 0.5 or less. The amount of transition metal W is 10
If it is less than 13, R2Fe17 will be stabilized, and if it exceeds 13, Fe will become the main phase and the ThMn12 structure will not be stabilized, so it is necessary that it be 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
Fe, Co, and additional metal elements M1, M2 were weighed as shown in Table 1 (alloy numbers 1-3, 6-10), high-frequency melting was performed in an inert gas, and the molten metal was cooled in a copper mold. After coarsely pulverizing the ingot, it was finely pulverized to a diameter of 3 to 5 μm using a jet mill using N2 gas. The fine powder was heated to 15K.
1 ton/cm when oriented in a static magnetic field of Oe
After press forming at a pressure of 1 to 2 degrees Celsius, the molded body was molded at a temperature of 1 to 2 degrees Celsius in an inert gas at a temperature of 1 to 1,250 degrees Celsius.
Sintering was performed for a period of time, followed by heat treatment at a temperature range of 500 to 900° C. for 1 hour or more, followed by rapid cooling. Table 1 shows the results of measuring the magnetic properties iHc of the sintered body using a self-recording magnetometer.
It was shown to. As a comparative example, an alloy without M1 or M2 added was alloy No. 4 and 5, and are also listed in Table 1. As shown in Table 1, when both M elements, M1 and M2, are added, the amount of addition can be reduced compared to when one of them is added, so less dilution with non-magnetic elements is required. Improved magnetic properties.

[0013]

[Table 1]

[0014]

[Effects of the Invention] According to the present invention, Th
By substituting rare earth sites with a small amount of Zr, Hf, etc., the R(Fe, Co)12-based magnetic material with an Mn12 structure can be stabilized even if the amount of Ti, etc. that replaces the transition metal is considerably reduced. Became. In addition, due to the synergistic effect of replacing both transition metal sites and rare earth sites,
It has become possible to stabilize by reducing the amount of each substitution. Therefore, it is possible to prevent a decrease in the saturation magnetic flux density and Curie point due to the introduction of non-magnetic metals, which was a problem with conventional 1-12 magnetic materials, and it has become possible to manufacture high-performance magnets using the same. In addition, since this 1-12 series magnet has Fe as its main component, it is advantageous in terms of resources, supply stability, and cost compared to SmCo series magnets that use a large amount of expensive Co. The value is extremely high.

Claims (1)

[Claims] Claim 1: The alloy composition is of the formula (R1-X M1X) [(
Fe1-YCoY)1-ZM2Z]W (However, R is Y
, Th and one or more rare earth elements mainly composed of Sm, M1 is Zr, Hf, Bi, Sn, In,
One or more elements selected from Pb, M2
are Ti, V, Cr, Mn, Mo, W, Nb, Ta, Si
, one or more elements selected from Al, 0
．． 01≦X≦0.4, 0.1≦Y≦0.5, 0.
01≦Z≦0.3, 10≦W≦13), and its main phase has a body-centered tetragonal ThMn12 structure, with M1 atoms replacing R atoms and M2 atoms replacing Fe or Co atoms. A rare earth permanent magnet characterized by: