JPH06192795A - Permanent magnet alloy - Google Patents

Abstract

PURPOSE:To improve magnetic properties, such as saturation magnetization, anisotropic magnetic field, and Curie temp., by adding specific elements to a (rare earth)-Fe-Co-Si type permanent magnet alloy. CONSTITUTION:The high performance rare earth permanent magnet alloy has a composition represented by RaTbSicMd. In the formula, R is at least one kind among rare earth elements including Y, T is Fe and/or Co, M is at least one element among B, C, N, Al, Ti, V, Cr, Mn, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Re, Rh, Pd, Ag, In, Sn, Sb, Hf, Ta, W, Pt, Au, and Bi, and further, 1<=a<=15% by atom, 0.1<=b<=100-a-c-d%, 5<=c<=30%, and 0.1<=d<=20%. In this alloy, main phase has body-centered tetragonal BaCd11 type crystal structure. The additive element M is an element effective in improving saturation magnetization, anisotropic magnetic field, and Curie temp.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-performance rare earth permanent magnet used for VCM (voice coil motor), rotating equipment and the like.

[0002]

2. Description of the Related Art Sm-Co and Nd-Fe-B based magnets are known as high performance rare earth permanent magnets that have been known and mass-produced. Rare earth elements Sm contained in these magnets,
Nd and the like play an important role in exerting a large magnetocrystalline anisotropy and are indispensable for obtaining a high coercive force.

However, since rare earth elements are generally expensive,
Containing a large amount of these is disadvantageous in terms of manufacturing cost. For this reason, it is necessary to reduce the rare earth content in order to reduce the cost of the high performance rare earth magnet.

An intermetallic compound S having a ThMn ₁₂ type crystal structure is used as a magnet material for reducing the content of rare earth elements.
The m-Fe-Ti system has been found (Japanese Patent Publication No. 4-50).
722). However, in reality, no sintered magnet has been produced with this composition system, and magnetic properties by ultra-quenching and mechanical alloying methods have been reported.

Similarly, Sm-Co and Nd-Fe-
An intermetallic compound N having a body-centered tetragonal BaCd ₁₁ type crystal structure as a magnet material containing less rare earth than that of B system
The d-Fe-Co-Si system has also been reported (J. Chem. Res.
earch (S), 1987, 138).

[0006]

However, the above intermetallic compounds have low saturation magnetization, anisotropic magnetic field, and Curie temperature,
It could not be used for practical high-performance rare earth magnets. The present invention has been made to solve the above problems, and an object of the present invention is to provide a high-performance rare earth permanent magnet with improved saturation magnetization, anisotropic magnetic field, and Curie temperature.

[0007]

Means for Solving the Problems The present inventors have conducted research to reduce the amount of expensive rare earth elements and improve the magnetic properties of an intermetallic compound having a BaCd ₁₁ type crystal structure. By adding an additional element to the Fe-Co-Si system, it is possible to significantly increase the saturation magnetization, anisotropic magnetic field, and Curie temperature when a permanent magnet having the present intermetallic compound as a main phase is formed. The present invention has been completed and the present invention has been completed.

Namely, the permanent magnet alloy according to the present invention, the composition _{formula: R a T b Si C M} d ( at least one of all the rare earth elements in the formula R is including Y, T is Fe or Co
1 or 2 of, M is B, C, N, Al, Ti, V,
Cr, Mn, Ni, Cu, Zn, Ga, Ge, Zr, N
b, Mo, Re, Rh, Pd, Ag, In, Sn, S
at least one of b, Hf, Ta, W, Pt, Au and Bi, and 1 ≦ a ≦ 15 at%, 0.1 ≦ b ≦ 100-a-
c-d at%, 5 ≤ c ≤ 30 at%, 0.1 ≤ d ≤ 20 a
t%), and the main phase has a body-centered tetragonal BaCd ₁₁ type crystal structure.

In the permanent magnet alloy according to the present invention,
The reason for limiting the composition as described above will be described below.

R is La, Ce, Pr, Nd, P
m, Sm, Eu, Gd, Tb, Dy, Ho, Er, T
As the rare earth element of m, Yb and Lu and Y, at least one kind or a mixture of two or more kinds thereof is used. Since R causes magnetic anisotropy in the material and gives a high coercive force, R is preferably 1 at% or more and 15 at% or less. R is 1
If it is less than at%, α-Fe is generated to lower the coercive force,
When it exceeds at%, the saturation magnetization is significantly reduced. In addition, a large amount of expensive rare earth element is used, which is disadvantageous because the manufacturing cost is increased.

Since Fe increases the magnetic moment, it is less than 0.
It is preferable to add 1 at% or more.

All of Co can be replaced with Fe, and the saturation magnetization becomes maximum around Fe: Co = 1: 1. Further Co
Has the effect of improving the corrosion resistance, but is expensive, so that it can be selected in an arbitrary amount ratio in consideration of the manufacturing cost.

Si is indispensable for stabilizing the BaCd ₁₁ type structure and is preferably 5 at% or more and 30 at% or less. S
When i is less than 5 at%, a BaCd11 type structure is not formed and 3
If it exceeds 0 at%, the saturation magnetization is significantly reduced.

As the M element, B, C, N, Al, T
i, V, Cr, Mn, Ni, Cu, Zn, Ga, Ge,
Zr, Nb, Mo, Re, Rh, Pd, Ag, In, S
At least one of n, Sb, Hf, Ta, W, Pt, Au and Bi or a mixture of two or more thereof is used.
Originally, the BaCd ₁₁ type crystal structure is R even if M element is not added.
-Fe-Co-Si system, but with M element of 20
When added in the range of at% or less, it is an element effective in improving the saturation magnetization, anisotropic magnetic field, and Curie temperature.

That is, the compound having the BaCd ₁₁ type crystal structure of the R—Fe—Co—Si system has a strong anisotropy of R, a high Curie temperature due to the 3d-3d exchange interaction of Fe or Co, and Fe or Co. High saturation magnetization due to the large magnetic moment of the 3d band gap of Co is expected.

However, in reality, since the RR distance is long, the anisotropic magnetic field is weak, and the Curie temperature is also low due to the weak 3d-3d exchange interaction, so that the gap is filled by the electron transfer from the Si atom to the 3d band and saturated. The magnetization is also low.

In the present invention, the M element is replaced by this R-Fe-Co-
By adding to the Si system, the RR distance is reduced to improve the anisotropic magnetic field, enhance the 3d-3d exchange interaction to improve the Curie temperature, and suppress the electron transfer from Si atoms to the 3d band. And is effective in improving the saturation magnetization.

In order to exhibit the above effect, it is preferable to add M in an amount of 0.1 at% or more.

Next, a method of manufacturing a permanent magnet according to the present invention will be described. The permanent magnet according to the present invention can be manufactured by a known manufacturing method, for example, melting, casting, heat treatment, or melting,
Casting, crushing, molding, sintering, heat treatment or melting, casting,
Obtained by ultra-quenching and heat treatment. Further, it can also be obtained by using a mechanical alloying method in which raw materials or powders of a molten alloy are solid-phase reacted with each other to form an alloy, or a gas-solid reaction method when C or N is added. Further, hot pressing may be performed instead of the heat treatment for integrating the alloy materials as described above. After the above alloy material is heat-treated, it can be mixed with an epoxy resin, a nylon-based resin or the like and molded to manufacture a bonded magnet.

The permanent magnet according to the present invention is mainly composed of a compound phase having a body-centered tetragonal stable BaCd ₁₁ type crystal structure, and has high saturation magnetization, an anisotropic magnetic field, and Curie temperature due to the added element M, and is It exhibits extremely excellent magnetic properties as compared with binary or ternary compounds.

[0021]

【Example】

(Example 1) R, Fe, Co, Si, Al, V, Ga, Mo, Hf, Zr, shown in Table 1
An alloy with a composition consisting of Pd, Ti, Mn and C elements was prepared by arc melting. The obtained ingot was crushed, and a part of it was nitrided and carbonized at 500 ° C. for 4 hours by the gas-solid reaction method. When the saturation magnetization (σs), anisotropic magnetic field (HA) and Curie temperature (Tc) of these powders were measured,
The results shown in Table 2 were obtained.

[0022]

[Table 1] ┃

[0023]

[Table 2]

As described above, R-Fe-Co-Si-M
High magnetic properties can be obtained with the system material.

(Example 2) R, Fe, Co, Si, Al, Z shown in Table 3
Alloys with compositions consisting of r, B, Cr, Mo, In, Ta, W, Nb, Cu, Ge and Sn were prepared by arc melting. The obtained ingot was coarsely crushed with a disc mill to an average size of 5 to 10 μm, finely pulverized with a jet mill to an average size of 2 to 3 μm, and subjected to transverse magnetic field molding. Sinter at 1000-1200 ℃ for 2 hours, then at 550-950 ℃ for 2 hours
After heat treatment for an hour, it was rapidly cooled. The residual magnetic flux density (Br), coercive force (iHc), and maximum energy product ((BH) max) of the anisotropic sintered body after heat treatment were measured, and the results shown in Table 4 were obtained.

[0026]

[Table 3] ┃

[0027]

[Table 4] ┃

As described above, R-Fe-Co-Si-M
Sintered magnets have high magnetic properties.

[0029]

As described above, according to the present invention, R-Fe
By adding the M element to the —Co—Si system, the saturation magnetization, anisotropic magnetic field, and Curie temperature of the intermetallic compound having a stable body-centered tetragonal BaCd ₁₁ type structure are improved, and further the present intermetallic compound is added. It is possible to provide a permanent magnet having a main phase and high magnetic properties.

[Brief description of drawings]

FIG. 1 shows a powder X-ray diffraction pattern of a BaCd ₁₁ type crystal structure.

Claims (1)

[Claims] 1. A composition _{formula: R a T b Si C M} d ( at least one of all the rare earth elements in the formula R is including Y, T is Fe
Alternatively, one or two types of Co, M is B, C, N, Al,
Ti, V, Cr, Mn, Ni, Cu, Zn, Ga, G
e, Zr, Nb, Mo, Re, Rh, Pd, Ag, I
At least one of n, Sn, Sb, Hf, Ta, W, Pt, Au, and Bi, and 1 ≦ a ≦ 15 at%, 0.1 ≦
b ≤ 100-a-c-d at%, 5 ≤ c ≤ 30 at%, 0.1
≤ d ≤ 20 at%) and the main phase is body-centered tetragonal Ba
A permanent magnet alloy having a Cd ₁₁ type crystal structure.