JPH05114507A - Permanent magnet and its manufacture - Google Patents

Abstract

PURPOSE:To obtain new magnetic material having high magnetic characteristics. CONSTITUTION:A permanent magnet composed of RaTMbMcADdCe and its manufacture (where R is at least one kind out of rare earth elements containing Y, TM is at least one kind out of Fe, Co and Ni, M is at least one kind out of Si, Ti, V, Cr, Mo and W, AD is at least one kind out of Al, Mn, Zn, Cu, Ga, Ge, Zr, Nb, Sn, Sb, Hf and Ta, 5<=a<=18at%, 65<=b<=85at%, 3<=c<=20at%, 0<d<=8at%, and 2<=e<=15at%).

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]

R- (F having a ThMn ₁₂ type crystal structure
The (e, Co)-(Si, Ti, V, Cr, Mo, W) system has already been reported as a permanent magnet material. For example, Japanese Patent Application Laid-Open No. 62-241302 reports a permanent magnet material of Sm-Fe-Ti alloy having a tetragonal crystal structure. This SmFe ₁₁ Ti compound has a saturation magnetization of 12
It has high magnetic properties of kG, an anisotropic magnetic field of 87 kOe, and a Curie temperature of 310 ° C. In addition, JP-A-2-1758
In Sm, Sm having a similar tetragonal ThMn ₁₂ type crystal structure
-Fe-V based materials are reported. The R—Fe—Ti-based material produces a ThMn ₁₂ type crystal structure with most combinations of rare earth elements, but exhibits uniaxial anisotropy only when R is Sm. When C, to penetrate the N to Sm ₂ Fe _17, the Sm ₂ Fe ₁₇ compound was plane anisotropy is changed to the uniaxial anisotropy, high saturation magnetization and the Curie temperature is obtained Coey like (J .Magn.Magn.Mat.87 (1990) L251). This is because C and N enter the Fe sublayer, and the saturation magnetization and the Curie temperature are increased by increasing the Fe-Fe interatomic distance, and when R is Sm, a high anisotropic magnetic field is obtained. When R is Sm, an anisotropic magnetic field of N is higher than that of C invading C and an anisotropic magnetic field can be obtained. Similarly to this, R having a ThMn ₁₂ type crystal structure
High saturation magnetization can be obtained by injecting N into a -Fe- (Si, Ti, V, Cr, Mo, W) -based compound. Yang et al. (J. Less-Common Met. 170 ('91) 37 ).

[0003]

The SmFe ₁₁ Ti-based material having the above-mentioned ThMn ₁₂ type crystal structure has preferable characteristics as a permanent magnet, but the saturation magnetization is Nd ₂ Fe.
_It has a drawback that it is lower than ₁₄ B type, Sm is more expensive than Nd, and high characteristics cannot be obtained by the sintering method. S
The m ₂ Fe ₁₇ N _x- based material has a saturation magnetization similar to that of Nd ₂ Fe ₁₄ B, but is expensive because Sm is used. In addition, R-Fe- (Si, Ti, V, Cr, Mo,
Characteristically, W) -N compounds are not sufficient. Therefore, R
As the material, inexpensive materials such as Ce, Pr, and Nd having a saturation magnetization, an anisotropic magnetic field, and a Curie temperature equal to or higher than Nd ₂ Fe ₁₄ B are required.

[0004]

The present inventors have found that ThMn
As a result of examining the effects of N, C, B, etc. in the _12- type crystal structure, it was found that the saturation magnetization, anisotropic magnetic field, and Curie temperature were highest when C was infiltrated. That is, the present invention relates to R _a TM _b M _c AD _d C _e (where R is at least one of rare earth elements including Y, TM is Fe, Co, N).
At least one of i, M is Si, Ti, V, Cr,
At least one of Mo and W, AD is Al, Mn, and Z
n, Cu, Ga, Ge, Zr, Nb, Sn, Sb, H
At least one of f and Ta, 5 ≦ a ≦ 18 at%, 65
≦ b ≦ 85 at%, 3 ≦ c ≦ 20 at%, 0 <d ≦ 8 at%, 2 ≦
e ≦ 15 at%) and a manufacturing method thereof. The present invention is particularly applicable to R _a Fe _b Ti _c AD _d C _e (wherein R is at least one of Ce, Pr and Nd, AD
Is Al, Mn, Zn, Cu, Ga, Ge, Zr, Nb,
At least one of Sn, Sb, Hf, and Ta, 5 ≦
a ≦ 18 at%, 65 ≦ b ≦ 85 at%, 3 ≦ c ≦ 20 at%, 0 <d
The composition of ≦ 8 at% and 2 ≦ e ≦ 15 at%) is most desirable. The magnet according to the present invention has a tetragonal ThMn ₁₂ type crystal structure. In the permanent magnet according to the present invention, C is ThM.
It is characterized in that it is included in the n ₁₂ type crystal structure as an interstitial type. In the present invention, the content of Ce or heavy rare earth element in the rare earth element R is preferably 1 at% or more. Further, the permanent magnet of the present invention is characterized in that the crystal field parameter A ₂ ⁰ of the crystal is positive. The manufacturing method of the permanent magnet according to the present invention is, for example, melting R, TM, M, AD, C so as to have a predetermined composition, casting, crushing,
The so-called powder metallurgy method of forming and sintering is used, or R, TM, M, AD,
It can be manufactured as a so-called bond magnet in which C is melted and cast, the melt is rapidly cooled, a heat treatment is applied, and a resin is used as a binder to mold. Hereinafter, the present invention will be described in detail by the crystal field theory. NdFe ₁₀ to ₁₁ (Si, Ti, V, C
The r, Mo, W) ₁ m to ₂ compound has a TnMn ₁₂ type crystal structure, but the magnetic anisotropy is in-plane and is not suitable for a permanent magnet. This is a crystal field parameter A of ThMn ₁₂ type crystal structure.
₂ ⁰ is negative, further because the negative also Stevens factor alpha _J For _{Nd, K 1 = -3J (J} -1/2) <r 2> α J A 2 0 ( where, <r ^2> : Nd is the square mean of the orbital radii of 4f electrons and is positive J: Total angular momentum, N
In the case of d, it is understood that the first-order anisotropy constant given by 9/2) becomes negative. Conversely, when R is Sm, α _J > 0
Therefore, K ₁ > 0 and uniaxial anisotropy occurs. But,
Nd (alpha _J 0 next to the uniaxial anisotropy <0) even K ₁ if A ₂ ⁰ is exactly the addition of some elements> is expected to be obtained. Therefore, the present inventors tried adding C element to NdFe ₁₁ Ti. As a result, it was found that this element entered the 2b site in FIG. 1 as a negative ion, which made A ₂ ⁰ positive and showed high uniaxial anisotropy even when R was Nd. Further C
The saturation magnetization and the Curie temperature are both increased due to the expansion of the crystal lattice due to the penetration of atoms. That is, the permanent magnet according to the present invention is R _a TM _b M _c AD _d
C _e (where R is at least one of rare earth elements including Y, TM is at least 1 of Fe, Co and Ni)
Seed, M is at least one of Si, Ti, V, CrMo, W, and AD is Al, Zn, Cu, Ga, Ge, Zr,
At least one of Nb, Sn, Sb, Hf, and Ta, 5 ≦ a ≦ 18 at%, 65 ≦ b ≦ 85 at%, 3 ≦ c ≦ 20 at
%, 0≤d≤8at%, 2≤e≤15at%). In the present invention, the rare earth element R is 5 at%
Or more and 18 at% or less, preferably 8 at% or more, 16
It is at% or less. R is Y, Ce, Pr, Nd, Gb,
In the case of Tb, Dy, Ho, a large anisotropic magnetic field is obtained,
High saturation magnetization is obtained in the case of Ce, Pr, and Nd. T
M is at least one of Fe, Co and Ni, and is 65a.
It is t% or more and 85 at% or less. The ThMn ₁₂ type crystal structure is formed in the entire composition range of Fe and Co, but the larger the amount of Fe, the higher the saturation magnetization / anisotropic magnetic field. Preferably Fe: C
It is near o = 3: 1. M is an element necessary for stabilizing the ThMn ₁₂ type crystal structure, and if 3 at% or less, there is no effect, and if it is added at 20 at% or more, the saturation magnetization decreases, which is not preferable. AD is an element necessary for increasing the coercive force, and is preferably 8 at% or less. Addition over this amount causes a decrease in saturation magnetization. C (carbon) is an element necessary to increase the saturation magnetization, anisotropic magnetic field and Curie temperature.
If it is at% or less, the effect is small, and if it is 15% or more, the saturation magnetization is lowered, which is not preferable. The magnet according to the present invention is produced by a sintering method and a molten metal quenching method. First,
C, V, Cr, Mo, W together with Fe, Co, Ni, etc.
Melts refractory elements such as R, Ti, Al, S
It dissolves together with elements such as i, Cu, and Ga. The obtained ingot is roughly crushed with a disc mill, a jaw crusher, etc., finely crushed with a jet mill, a ball mill, etc., then molded in a magnetic field and sintered. 500 of the obtained sintered body
By heat treatment at -900 ° C, a magnet with high coercive force can be obtained. When creating a magnet by the molten metal quench method,
Similar to the sintering method, a molten alloy is prepared and the molten metal is quenched. The obtained flaky sample is subjected to heat treatment or the like, if necessary, to obtain magnet characteristics.

[0005]

The important point in the present invention is to add carbon (C). As a result of examining the effects of N, C, B and the like in the ThMn ₁₂ type crystal structure, the present inventors have found that the saturation magnetization, anisotropic magnetic field, and Curie temperature are highest when C is infiltrated. .. This is because the conventional R ₂ Fe ₁₇
It shows the opposite trend to the compound. R- (Fe, Co)
-(Si, Ti, V, Cr, Mo, W) system, R
When Pr is Pr and Nd, the ThMn ₁₂ type compound is difficult to stably generate, and when R is Ce and a heavy rare earth element, it is stably generated. However, high saturation magnetization is obtained when R is Pr and Nd. Therefore, in order to stabilize the ThMn ₁₂ type crystal structure and obtain high saturation magnetization, by containing 1 at% or more of Ce or heavy rare earth based on Nd as R, the ThMn ₁₂ type crystal structure is stabilized and high saturation is achieved. It was found that magnetization could be obtained.

[0006]

EXAMPLES (Example 1) Rare earth elements, transition metals, (Si, Ti, V, Cr, Mo, W) and AD shown in Table 1
An alloy having a composition of elements was prepared by arc melting.
The obtained ingot was ultraquenched by the molten metal quenching method.
The obtained flaky sample was dipped in an epoxy resin and solidified after molding in a magnetic field. The magnetic properties obtained are shown in Table 1.

[Table 1] (Example 2) Rare earth elements, transition metals, (S
An alloy having a composition consisting of i, Ti, V, Cr, Mo, W) and an AD element was produced by arc melting. The obtained ingot was roughly pulverized with a disc mill and then finely pulverized with a jet mill. The obtained fine powder was molded in a magnetic field and sintered. The sample was heat-treated at 650 ° C. for 1 hour. The magnetic properties obtained are shown in Table 2.

[Table 2]

[0007]

As described above, R- (Fe, Co, Ni)-(Si, Ti, V, which has a ThMn ₁₂ type crystal structure,
A magnet material having high magnetic properties was obtained by infiltrating C into the (Cr, Mo, W) system.

[Brief description of drawings]

FIG. 1 is a ThMn ₁₂ type body-centered tetragonal structure according to the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Keisuke Nakamura 5200 Mikashiri, Kumagaya-shi, Saitama Hitachi Metals Co., Ltd.

Claims (8)

[Claims] 1. R _a TM _b M _c AD _d C _e (where R is Y
At least one of the rare earth elements, including TM, is F
At least one of e, Co and Ni, M is Si and T
At least one of i, V, Cr, Mo and W, AD is Al, Mn, Zn, Cu, Ga, Ge, Zr, Nb, S
At least one of n, Sb, Hf, and Ta, 5 ≦ a
≦ 18at%, 65 ≦ b ≦ 85at%, 3 ≦ c ≦ 20at%, 0 <d
A permanent magnet having a composition of ≤8 at% and 2 ≤e≤15 at%). 2. The magnet according to claim 1, wherein the magnet is tetragonal ThMn ₁₂
A permanent magnet having a type crystal structure. 3. The permanent magnet according to claim 1, wherein C is included in the ThMn ₁₂ type crystal structure as an interstitial type. 4. The permanent magnet according to claim 1, wherein the content of Ce or heavy rare earth element in the rare earth element R is 1a.
Permanent magnet characterized by being t% or more. 5. The permanent magnet according to claim 1, wherein the crystal field parameter A ₂ ⁰ of the crystal is positive. 6. R _a TM _b M _c AD _d C _e (where R is Y
At least one of the rare earth elements, including TM, is F
At least one of e, Co and Ni, M is Si and T
At least one of i, V, Cr, Mo and W, AD is Al, Mn, Zn, Cu, Ga, Ge, Zr, Nb, S
At least one of n, Sb, Hf, and Ta, 5 ≦ a
≦ 18at%, 65 ≦ b ≦ 85at%, 3 ≦ c ≦ 20at%, 0 <d
≤8 at%, 2 ≤e ≤15 at%) of the permanent magnet prepared by melting, casting, crushing, shaping, and sintering R, TM, M, AD, C so that the composition is represented by Production method. 7. R _a TM _b M _c AD _d C _e (where R is Y
At least one of the rare earth elements, including TM, is F
At least one of e, Co and Ni, M is Si and T
At least one of i, V, Cr, Mo and W, AD is Al, Mn, Zn, Cu, Ga, Ge, Zr, Nb, S
At least one of n, Sb, Hf, and Ta, 5 ≦ a
≦ 18at%, 65 ≦ b ≦ 85at%, 3 ≦ c ≦ 20at%, 0 <d
≤8 at%, 2 ≤e≤15 at%) R, TM, M, AD, C are melted and cast, molten metal is rapidly cooled, heat treatment is applied, and a permanent magnet is formed by using a resin as a binder. Manufacturing method. 8. R _a Fe _b Ti _c AD _d C _e (wherein R is at least one of Ce, Pr and Nd, AD is Al,
Mn, Zn, Cu, Ga, Ge, Zr, Nb, Sn, S
At least one of b, Hf, and Ta, 5 ≦ a ≦ 18a
t%, 65 ≦ b ≦ 85at%, 3 ≦ c ≦ 20at%, 0 <d ≦ 8at
%, 2 ≦ e ≦ 15 at%) of a permanent magnet.