JP2002118010A - Magnet material and bonded magnet using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the magnetic characteristics of a magnet material, having a Th2Ni17 crystal phase as an essential component, by refining the crystal structure of the material. SOLUTION: The magnet material has a composition expressed by (R1XR21-X)YBZT1-Y-Z}1-QNQ (where R1, R2, and T respectively denote at least one kind of element selected from among rare-earth elements, at least one kind of element selected from among Zr, Hf, Ti, and Sc, and at least one kind of element selected from among of Fe and Co, and X, Y, Z, and Q respectively meet the relations of 0.5<=X<1, 0.05<=Y<=0.2, 0<=Z<=0.1, and 0.1<=Q<=0.2) and, in addition, contains the Th2Ni17 crystal phase at a ratio of >=5 vol.%. The magnet material has such a recrystalline structure with the mean diameter of crystal grains lying within the range of 0.02-50 μm. This magnet material is obtained by performing HDDR on a mother alloy, having the Th2Ni17 crystal phase as the main phase.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a magnet material used as a high-performance permanent magnet and a bonded magnet using the same.

[0002]

2. Description of the Related Art Rare earth magnets such as Sm-Co magnets and Nd-Fe-B magnets have been known as high performance permanent magnets. These magnets include Fe and C
o is contained in a large amount and contributes to an increase in the saturation magnetic flux density. In addition, rare earth elements such as Nd and Sm cause very large magnetic anisotropy due to the behavior of 4f electrons in a crystal field. Thereby, the coercive force is increased.

[0003] Such rare earth-based high-performance magnets are mainly used for electrical equipment such as speakers, motors and measuring instruments. In recent years, there has been an increasing demand for miniaturization of various types of electric equipment, and in order to meet the demand, higher-performance permanent magnets have been required. To meet such demands, Fe-RN magnets (R is an element selected from Y, Th and lanthanoid elements) (see Japanese Patent Publication No. 5-82041) have been proposed, but are not always satisfactory. No properties have been obtained.

Further, Japanese Patent Application Laid-Open No. 8-191006 discloses that Th
R-Zr-Fe (Co) -N having a phase having a ₂ Ni ₁₇ type crystal structure (hereinafter referred to as a Th ₂ Ni ₁₇ type crystal phase) as a main phase
A series magnet material (R: rare earth element) is described. Th
_{The 2} Ni ₁₇ type crystal phase can contain a larger amount of Fe and Co than a phase having a Th ₂ Zn ₁₇ type crystal structure (Th ₂ Zn ₁₇ type crystal phase). Therefore, Th ₂ Ni
A magnet material having a _17- type crystal phase as a main phase is expected as a material for forming a permanent magnet with further improved saturation magnetic flux density and the like.

[0005]

However, the magnet material based on the conventional manufacturing method and having a Th ₂ Ni ₁₇ type crystal phase as a main phase has a disadvantage that the crystal structure is relatively coarse. As a method for refining the crystal structure, there are a quenching method and a mechanical alloying method as described in JP-A-8-191006. However, these manufacturing methods are disadvantageous in terms of improving production efficiency and reducing manufacturing costs.

On the other hand, in R-Fe-B based magnet materials, HDDR is used as a technique for obtaining a fine crystal structure.
(Hydrogenation-Disproportionation-Desorption-Reco
A mbination method is known (see JP-A-1-132106). The HDDR method is a method described below. For example, in the case of an R-Fe-B based magnet material, is first heat-treated the R-Fe-B base alloy as a main phase an R ₂ Fe ₁₄ B phase in a hydrogen atmosphere, RH _x, Fe ₂ B, the Fe Transform into each phase.
Next, H ₂ is removed from the material in a dehydrogenation step, and R _{2 is} removed again.
Produces Fe ₁₄ B phase. The resulting alloy has an average grain size
It has a recrystallized structure mainly composed of a fine R ₂ Fe ₁₄ B phase of about 0.05 to 3 μm. As described above, the HDDR method can make the structure finer only by the atmosphere treatment using the electric furnace,
Excellent in manufacturing cost.

Several examples have been reported in which the HDDR method is applied to magnet materials other than R-Fe-B. For example, Ma
t. Chem. Phys. 32, 280-285 (1992) discloses that an Sm ₂ Fe ₁₇ N _x- based magnet material having a Th ₂ Zn ₁₇ type crystal phase as a main phase is HDDR.
It describes that it was produced by applying the method.

Further, Japanese Patent Application Laid-Open No. 8-37122 discloses that Th ₂
RMT alloy having a Zn ₁₇ type crystal phase as a main phase (R: rare earth element, M: metal element such as Al, Ti, V, Cr,
T: Fe, Fe—Co) is subjected to an HDDR process, and then a nitriding process is performed to obtain a Th ₂ Zn ₁₇ type crystal phase and T
A method for producing an RMTN magnet material having a bCu ₇ type crystal phase as a main phase is described. Also, JP-A-4-26
No. 0302 discloses a crystal structure of the R ₂ (T, M) ₁₇ system (R:
Rare earth element, T: Fe, Fe-Co, M: Zr, Hf,
It describes that an HDDR treatment is performed on an alloy having a metal element such as Nb or Ta).

The HDDR processes described in these publications are all applied to alloys having a Th ₂ Zn ₁₇ type crystal phase as a main phase. Further, in Japanese Patent Application Laid-Open No. 8-37122, an anisotropic magnet powder is obtained. In Japanese Patent Application Laid-Open No. Hei 4-260302, M element is added to impart anisotropy to the magnet material, and the crystal structure of the magnet material is described as R ₂ (T, M) ₁₇ type. The crystal structure without M is Th ₂ Z
n ₁₇ type, and Th ₂ Z
n ₁₇ type.

As described above, the HDDR method is known as a technique for refining the crystal structure of a magnet material. However, there is no example of applying the HDDR method to a magnet material containing a Th ₂ Ni ₁₇ type crystal phase as an essential component.

SUMMARY OF THE INVENTION The present invention has been made to address such a problem, and has been made to improve magnetic properties by reducing the crystal structure of a magnet material having a Th ₂ Ni ₁₇ type crystal phase as an essential component. It is another object of the present invention to provide a high-performance bonded magnet using such a magnet material and further using such a magnet material.

[0012]

Means for Solving the Problems The inventors of the present invention have made intensive studies to achieve the above-mentioned object, and as a result, have found that Th ₂ N
HDDR process even for mother alloy i ₁₇ type crystal phase as a main phase was found to be effective. And Th ₂ Ni ₁₇
By subjecting a mother alloy having a type crystal phase as a main phase to HDDR treatment, a magnet material containing a Th ₂ Ni ₁₇ type crystal phase as an essential component and having a fine recrystallized structure can be obtained.

The present invention has been made based on such findings. Magnet materials of the present invention as described in claim 1, the general _{^{formula: {(R 1 X R 2}} 1-X) Y B Z T 1-YZ} 1-Q N Q ( In the formula, R ¹ is a rare earth X represents at least one element selected from elements, R ² represents at least one element selected from Zr, Hf, Ti and Sc; T represents at least one element selected from Fe and Co; , Z and Q are respectively 0.5 ≦ X <1, 0.05 ≦ Y ≦ 0.2, 0 ≦ Z ≦ 0.
1. A magnet material having a composition represented by the following formula: 0.1 ≦ Q ≦ 0.2) and containing 5% by volume or more of a Th ₂ Ni ₁₇ type crystal phase, and having an average crystal grain size of 0.02 to It is characterized by a range of 50 μm.

The magnetic material of the present invention has a recrystallized structure due to absorption and desorption of hydrogen. More specifically, as described in claim 3, the master alloy having a Th ₂ Ni ₁₇ type crystal phase as a main phase has a recrystallized structure in which hydrogen is absorbed and desorbed and recrystallized.

The magnetic material of the present invention preferably has a Th ₂ Ni ₁₇ type crystal phase as a main phase. However, depending on manufacturing conditions, a Th ₂ Zn ₁₇ type crystal phase, a TbCu ₇ type crystal phase, a ThM
n ₁₂ type crystal phase and the like may also be obtained magnet material mainly phase. The magnet material of the present invention preferably further contains a trace amount of boron. The boron content is 0 <Z ≦ 0.1 as the value of Z.
It is preferable to be within the range.

A bonded magnet according to the present invention comprises a mixture of the above-described magnet material of the present invention and a binder, wherein the mixture has a magnet-shaped compact. .

[0017]

Embodiments of the present invention will be described below.

The magnet material of the present invention have the general _{^{formula: {(R 1 X R 2}} 1-X) Y B Z T 1-YZ} 1-Q N Q ... (1) ( In the formula, R ¹ is a rare earth element R ² represents at least one element selected from Zr, Hf, Ti and Sc, T represents at least one element selected from Fe and Co, X, Y, Z and Q are respectively 0.5 ≦ X <1, 0.05 ≦ Y ≦ 0.2, 0 ≦ Z ≦ 0.
1, a number that satisfies 0.1 ≦ Q ≦ 0.2) and contains at least 5% by volume of a Th ₂ Ni ₁₇ type crystal phase, and furthermore, an average crystal in the range of 0.02 to 50 μm. Has a particle size.

First, the reasons for blending the components constituting the magnet material of the present invention and the reasons for defining the blending amounts will be described.

The rare earth element as the R ¹ element is a component that brings a large magnetic anisotropy to the magnet material and thus imparts a high coercive force. As such R ¹ element, L
a, Ce, Pr, Nd, Sm, Eu, Gd, Tb, D
Rare earth elements such as y, Ho, Er, Tm, Lu, and Y are listed. Among these, it is particularly preferable that 50 atom% or more of the R ¹ element is Sm. Thereby, the magnetic anisotropy of the main phase can be increased, and the coercive force can be increased.

The R ² element is at least one element selected from Zr, Hf, Ti and Sc. Such R ²
Element, by the action such as reducing the average atomic radius of the rare earth site occupies a rare earth site of the main phase, Th ₂ N
It plays an important role in obtaining the _i17 type crystal structure.

Usually, in a binary alloy of RT (T is Fe or Co), R is Ce, Pr, Nd, Sm,
When Gd is used, a Th ₂ Zn ₁₇ type crystal phase is obtained,
R is Tb, Dy, Ho, Er, Eu, Tm, Yb,
It is known that when Lu and Y are used, a Th ₂ Ni ₁₇ type crystal phase is obtained. For such a system, R ²
By blending the element, a Th ₂ Ni ₁₇ type crystal phase can be obtained even when Sm or Nd is used as the R element (R ¹ element). Further, the R ² element also has an effect of suppressing the precipitation of the α-Fe phase during the manufacturing process of the magnet material and improving the magnetic properties.

In the above formula (1), the total amount Y of the R ¹ element and the R ² element is in the range of 0.05 ≦ Y ≦ 0.2. this is,
This is because by increasing the total amount Y of the R ¹ element and the R ² element, a large magnetic anisotropy can be obtained and a high coercive force can be provided. However, if the R ¹ element and the R ² element are excessively mixed, the magnetization is lowered. The value of Y is
More preferably, the range is 0.09 ≦ Y ≦ 0.15.

Further, increasing the ratio X of the R ¹ element to the total amount of the R ¹ element and the R ² element is advantageous in obtaining a high coercive force. Therefore, the value of X is in the range of 0.5 ≦ X <1. However, if the ratio of the R ¹ element is too large, it becomes difficult to obtain a Th ₂ Ni ₁₇ type crystal phase. Th ₂ N
In order to obtain a magnet material having an i ₁₇ type crystal phase as a main phase, X
Is preferably in the range of 0.5 ≦ X ≦ 0.85. X
Is more preferably in the range of 0.65 ≦ X ≦ 0.85.

The T element is at least one element selected from Fe and Co, and has a function of increasing the saturation magnetization of the magnet material. An increase in the saturation magnetization leads to an increase in the remanent magnetization, and the maximum magnetic energy product increases accordingly. Such a T element is preferably contained in the magnet material in an amount of 70 atomic% or more, whereby the saturation magnetization can be effectively increased. Further, in order to further increase the saturation magnetization of the magnet material, 50 atomic% or more of the T element is
e is preferable.

Part of the T element is V, Cr, Mo, W, M
It may be replaced with at least one element (M element) selected from n, Ga, Al, Sn, Ta, Nb, Si and Ni. By substituting a part of the T element with such an M element, it is possible to improve the magnetic properties and also to improve various practically important properties such as corrosion resistance and heat resistance. However, if the T element is replaced with an excessively large amount of the M element, the magnetic properties will be markedly degraded.

In the magnet material of the present invention, B (boron) is not necessarily an element to be blended. However, blending B increases the processing conditions when performing the HDDR process described later in detail, and increases the alloy structure. (Recrystallized structure) can be more uniformly refined. Further, B has an action of suppressing the precipitation of the α-Fe phase and the like. With these, the residual magnetization and the maximum energy product of the magnet material can be improved.

From the above, it is preferable that the content of B is in the range of 0 <Z ≦ 0.1 as the value of Z in the equation (1). If the value of Z indicating the B content exceeds 0.1, the amount of the R ₂ Fe ₁₄ B phase and the like generated in the heat treatment step increases, and the magnetic characteristics deteriorate. More preferably, the value of Z is 0.05 or less. In order to more effectively obtain the effect of blending B, the value of Z is more preferably 0.005 or more.

N (nitrogen) mainly exists at the interstitial position of the main phase, and has a function of improving the Curie temperature and magnetic anisotropy of the main phase as compared with the case where N is not contained. Among them, improvement of the magnetic anisotropy is important for giving a large coercive force to the magnet material. N exerts its effect with a small amount of compounding, but if it is contained too much, the amorphous phase or α
-Fe phase is easily generated, and deteriorates magnetic properties of the magnet material. Therefore, the value of Q indicating the content of N is 0.1 ≦ Q
≦ 0.2. More preferably, the value of Q is in the range of 0.14 ≦ Q ≦ 0.18.

A part of N may be replaced by hydrogen (H). H may be introduced into the magnet material by a heat treatment based on the HDDR method described later in detail, and exists mainly at the interstitial position of the main phase like N. H contributes to improvement of magnet properties such as coercive force. However, if the substitution amount of H is too large, the effect of improving the Curie temperature and magnetic anisotropy of the main phase is reduced. Therefore, the substitution amount of N by H is preferably set to 50 atomic% or less. Further, a part of N may be replaced with C or P. In this case, the substitution amount is preferably 50 atomic% or less of N, including the substitution amount by H. in this way,
Part of N (50 atomic% or less) can be replaced with at least one element (X element) selected from H, C and P.

The magnet material represented by the above formula (1) is allowed to contain unavoidable impurities such as oxides.

The magnetic material of the present invention having the above-mentioned composition has a fine crystal structure containing at least 5% by volume of a Th ₂ Ni ₁₇ type crystal phase and an average crystal grain size in the range of 0.02 to 50 μm. In particular, the magnetic material of the present invention preferably has a Th ₂ Ni ₁₇ type crystal phase as a main phase. Here, the main phase refers to a phase having the largest volume ratio among constituent phases in the alloy. As will be described in detail later, such a magnet material is obtained by subjecting a master alloy having a Th ₂ Ni ₁₇ type crystal phase as a main phase to HDDR processing.

The Th ₂ Ni ₁₇ type crystal phase is, for example, TbCu ₇
It has a higher coercive force than the type crystal phase. In addition, Th ₂ N
The i ₁₇ type crystal phase has Fe and C as compared with the Th ₂ Zn ₁₇ type crystal phase.
o (T element) can be contained in a large amount. For example, R ¹
When Sm is used as the element and Fe is used as the T element, Th
_The 2Zn ₁₇ type crystal phase has a narrow solid solution region, and Fe exceeding a stoichiometric ratio of 2:17 (Sm ₂ Fe ₁₇ phase) precipitates as an α-Fe phase or the like. This degrades the magnet properties.

On the other hand, the Th ₂ Ni ₁₇ type crystal phase has a wide solid solution region on the Fe-rich side, and a Th ₂ Ni ₁₇ type crystal phase is formed even if Fe is slightly larger than the stoichiometric ratio of 2:17. Specifically, even if the composition ratio is about Sm ₂ Fe ₁₇ to ₁₉ , Th ₂ Ni ₁₇
A type crystal phase is formed. As a result, the magnetic flux density can be increased, and the precipitation of a phase that deteriorates the magnet properties such as the α-Fe phase can be suppressed.

The Th ₂ Ni ₁₇ type crystal phase greatly contributes to improving the performance of the magnet material. For this reason, the magnetic material of the present invention contains at least 5% by volume or more of the Th ₂ Ni ₁₇ type crystal phase. Among the constituent phases of the magnet material, Th ₂ Ni
_If the volume ratio of the type ₁₇ crystal phase is less than 5%, good magnet properties cannot be obtained. Further, in order to make full use of the properties of the Th ₂ Ni ₁₇ type crystal phase and improve the performance of the magnet material, the magnet material of the present invention has a Th ₂ Ni ₁₇ type crystal phase as a main phase. Contains 50 Th ₂ Ni ₁₇ type crystal phases.
It is preferred that the content be at least volume%. More preferably, the Th ₂ Ni ₁₇ type crystal phase contains 80% or more by volume. The constituent phases of the magnet material can be confirmed by X-ray diffraction or the like.

The magnetic material of the present invention contains at least 5% by volume or more of the Th ₂ Ni ₁₇ type crystal phase, and further has a fine recrystallized structure based on HDDR treatment, that is, a recrystallized structure due to absorption and desorption of hydrogen. Have. The recrystallized structure by absorption and desorption of hydrogen is fine and excellent in uniformity,
An average grain size in the range of 50 μm is obtained. By setting the average crystal grain size of the magnet material to 50 μm or less, the coercive force and the residual magnetization can be increased. More preferably, the average crystal grain size of the magnetic material of the present invention is 10 μm or less.
However, if the average crystal grain size is less than 0.02 μm, disadvantages such as difficulty in magnetizing occur. The average crystal grain size of the recrystallized structure is particularly preferably in the range of 0.02 to 1 μm.

In the present invention, the method for measuring the average crystal grain size t (μm) of the magnet material is as follows.
When the cross-sectional area of a crystal grain observed from a metallographic photograph of a magnet material using a transmission electron microscope is defined as S _n (μm ² ),
The crystal grain size r _n (μm) is defined by the following equation.

(Equation 1) The average crystal grain size t is the average value of each crystal grain size r _n, i.e. is defined by the following equation.

(Equation 2) N is the number obtained by measuring the crystal grain size, and is preferably 60 or more.

At least 5% by volume of a Th ₂ Ni ₁₇ type crystal phase
The magnet material including the above, and the magnet material having a Th ₂ Ni ₁₇ type crystal phase as a main phase have excellent magnetic properties such as a high saturation magnetic flux density as described above, and further, have an average crystal grain size of 0%. .
With a fine crystal structure (recrystallized structure) in the range of 02 to 50 μm, coercive force, residual magnetization, and the like can be increased. As described above, the magnet material of the present invention is intended to further improve the performance, and corresponds to the miniaturization and higher performance of various electric components.

Here, the main phase of the magnetic material of the present invention is Th
It is not limited to ₂ Ni ₁₇ type crystal phase. Depending on the composition of the mother alloy to be subjected to HDDR treatment, HDDR treatment conditions, nitriding treatment conditions, etc., a main phase may be a Th ₂ Zn ₁₇ type crystal phase, a TbCu ₇ type crystal phase, a ThMn ₁₂ type crystal phase, or the like. In any case, the Th ₂ Ni ₁₇ type crystal phase contains at least 5% by volume or more. When the amount of the R ² element in the master alloy is relatively small, a Th ₂ Zn ₁₇ type crystal phase is likely to appear. In addition, when the amount of Ti in the R ² element is large or the amount of the M element that partially replaces the T element is increased, a TbCu ₇ type crystal phase or a ThMn ₁₂ type crystal phase is likely to appear.

The main phase of the magnetic material of the present invention can be selected according to the application. For example, when a high remanent magnetization and a maximum energy product are required, it is preferable to use a Th ₂ Ni ₁₇ type crystal phase as a main phase. For a magnet material requiring a high coercive force, it is preferable that the main phase be a Th ₂ Zn ₁₇ type crystal phase. In a magnetic material requiring high thermal stability, a TbCu ₇ type crystal phase or a ThMn ₁₂ type crystal phase can be used as a main phase. The term “main phase” as used herein means the component phase having the largest volume ratio among the constituent phases in the alloy, and specifically, preferably has a volume ratio of 50% or more.

In the present invention, the volume occupancy of each phase generated in the magnet material is determined by an area analysis method from a transmission electron micrograph of a cross section of the magnet material. The volume ratio can be approximately expressed by the cross-sectional area ratio by the area analysis method. The volume occupancy in the present invention is an average value obtained by measuring 10 points.

The magnet material of the present invention can be manufactured, for example, as follows. First, a predetermined amount of R ¹ , R ² ,
An ingot containing each element of T and, if necessary, B and M elements is prepared by arc melting, high frequency melting or the like. This master alloy has a main phase of a Th ₂ Ni ₁₇ type crystal phase. Such an alloy ingot is subjected to a heat treatment at a temperature of about 300 to 1200 ° C. for 0.1 to 200 hours in an atmosphere of an inert gas such as Ar or He or a vacuum as necessary. By performing such a heat treatment, α
-A master alloy with less precipitation of the Fe phase and the like is obtained.

The mother alloy used in the manufacture of the magnetic material of the present invention have the general ^{_{formula: (R 1 X R 2 1}} -X) Y B Z T 1-YZ ... (2) ( In the formula, R ¹ is a rare earth element R ² represents at least one element selected from Zr, Hf, Ti and Sc; T represents at least one element selected from Fe and Co; X, Y and Z is a number that satisfies 0.5 ≦ X <1, 0.05 ≦ Y ≦ 0.2, and 0 ≦ Z ≦ 0.1, respectively).

By satisfying such an alloy composition, the main phase of the master alloy can be easily made to be a Th ₂ Ni ₁₇ type crystal phase. However, even if the alloy composition is the same, the crystal phase is different depending on the manufacturing conditions. Therefore, the main phase of the mother alloy is changed to a Th ₂ Ni ₁₇ type crystal by controlling the conditions for heat treatment after melting and casting the mother alloy. Phase.

Next, the obtained master alloy was subjected to ball milling, brown milling, stamp milling or the like to obtain an average particle size of several tens.
Pulverize to about μm to several hundred μm. A recrystallization step by absorbing and desorbing hydrogen is performed on such a master alloy powder. That is, HDDR (Hydrogenation-
(Disproportionation-Desorption-Recombination) treatment. As described above, the Th ₂ Ni ₁₇ type crystal phase is Fe
Since the solid solution region is wide on the rich side and the precipitation of a phase that degrades the magnet properties such as the α-Fe phase can be suppressed, the HD
After the DR treatment, a magnet material having less α-Fe phase and excellent characteristics can be obtained with good reproducibility.

In the HDDR process, first, the mother alloy powder is heated at a temperature of about 650 to 800 ° C. for 30 minutes in a hydrogen gas atmosphere.
Heat treatment for about 1 hour to allow the master alloy to absorb hydrogen. The absorption step of this hydrogen, Th ₂ Ni ₁₇ type crystal phase RH _x
The crystal structure is refined while decomposing into a phase or an α-Fe phase.

Next, while maintaining the same temperature, or
Dehydrogenation is performed by evacuation while raising the temperature by about 10 to 100 ° C. Thereafter, it is cooled to room temperature. By this dehydrogenation step, a crystal phase containing at least 5% by volume or more of the Th ₂ Ni ₁₇ type crystal phase is recrystallized. The crystal phase due to this recrystallized structure maintains a fine structure accompanying the absorption of hydrogen. Therefore, the average crystal grain size is in the range of 0.02 to 50 μm, and even 0.0
A fine crystal structure (recrystallized structure) in the range of 2-1 μm is obtained.

The constituent phases of the recrystallization structure are a Th ₂ Ni ₁₇ type crystal phase, a Th ₂ Zn ₁₇ type crystal phase, a TbCu ₇ type crystal phase, and a Th ₂ Ni ₁₇ type crystal phase.
It becomes a Mn ₁₂ type crystal phase or the like. At least 5% by volume or more of the Th ₂ Ni ₁₇ type crystal phase is contained. The main phase of the recrystallized structure can be any one of the four types of crystal phases described above. However, as described above, in the present invention, in order to increase the magnetic flux density and the performance of the magnet material, Th _{2 is used.} It is preferred that the Ni ₁₇ type crystal phase be the main phase.

Thereafter, the alloy powder that has undergone the recrystallization step by absorption and desorption of hydrogen is heat-treated (nitrided) in a nitrogen-containing atmosphere to obtain the desired powdery magnet material. The resulting magnet material is isotropic magnet particles. Nitriding treatment is performed in a nitrogen gas atmosphere of 0.01 to 10 atm.
It is preferable to carry out at a temperature of 400 to 500 ° C. The nitriding time under such conditions is preferably 0.1 to 300 hours.

The atmosphere during the nitriding treatment was replaced with nitrogen gas.
A nitrogen compound gas such as ammonia gas may be used.
When ammonia gas is used, the nitridation reaction rate can be increased. At this time, the rate of the nitriding reaction can be controlled by simultaneously using gases such as hydrogen, nitrogen, and argon.

In the manufacturing method of the present invention as described above, T
Since the mother alloy having the h ₂ Ni ₁₇ type crystal phase as the main phase is subjected to HDDR treatment, a high-performance magnet material having a small amount of α-Fe phase and a fine recrystallized structure can be obtained. Although a fine structure can be realized by a quenching method or the like, omitting the quenching step can improve the production efficiency of the magnet material and reduce the manufacturing cost. The recrystallized structure also has an advantage that a uniform fine structure is easily obtained. Furthermore, a magnet material having a fine Th ₂ Ni ₁₇ type crystal phase as a main phase can be obtained with good reproducibility.

The magnet material of the present invention is suitable, for example, as a constituent material of a bonded magnet. Hereinafter, a method for producing a bonded magnet from the magnet material of the present invention will be described. In addition,
When manufacturing a bonded magnet, usually, a magnet material is pulverized and used. However, if grinding has already been performed in the above-described magnet material manufacturing process, this can be omitted.

(A) A powder of the magnetic material of the present invention is mixed with an organic binder and compression-molded or injection-molded into a desired shape to produce a bonded magnet. As the binder, for example, an epoxy-based or nylon-based resin can be used. When a thermosetting resin such as an epoxy resin is used as the binder, it is preferable to perform a curing treatment at a temperature of 100 to 200 ° C. after molding into a desired shape. When a bonded magnet is manufactured by compression molding, a permanent magnet having a high magnetic flux density can be manufactured by applying a magnetic field at the time of pressurization and aligning crystal orientations.

(B) A powder of the magnetic material of the present invention is mixed with a low melting point metal or a low melting point alloy and then compression molded to produce a metal bonded magnet. In this case, a low melting point metal or a low melting point alloy functions as a binder. As the low melting point metal, for example, Al, Pb, Sn, Zn, Cu, Mg or the like can be used. As the low melting point alloy, an alloy containing the above low melting point metal can be used. Also in this case, a permanent magnet having a high magnetic flux density can be manufactured by applying a magnetic field and aligning the crystal orientations.

[0055]

Next, specific examples of the present invention will be described.

Examples 1 to 8 First, high-purity raw materials were mixed at a predetermined ratio, and were melted at a high frequency in an Ar atmosphere to produce mother alloy ingots. Then, each of these master alloy ingots was placed in a vacuum for 11 hours.
After heat treatment under the conditions of 00 ° C. × 48 hours, each was pulverized by a ball mill in an Ar atmosphere so as to have an average particle size of about 4 to 5 μm. When X-ray diffraction of each mother alloy was performed,
It was confirmed that each had a Th ₂ Ni ₁₇ type crystal phase as a main phase.

Next, each alloy powder was placed in a heat treatment furnace, and the inside of the furnace was evacuated to a vacuum of 2 × 10 ⁻³ Pa. Then, the temperature was raised to 730 ° C. while flowing 1 atm of H ₂ gas into the furnace. Hold at that temperature for 30 minutes. Next, evacuation was performed again, and after the degree of vacuum reached 2 × 10 ⁻³ Pa, the temperature was raised again to 800 ° C. Then put 1 in the furnace
Each powder was rapidly cooled by flowing Ar gas at atmospheric pressure. X-ray diffraction of each of the obtained alloy powders revealed that each powder was Th ₂ Ni
It was confirmed that the type ₁₇ crystal phase was the main phase.

Next, in order to make each alloy powder contain nitrogen, each alloy powder was heat-treated at 450 ° C. × 25 hours in a nitrogen gas at 1 atm. This nitriding increased the mass of each material by 3.0 to 3.9%. Table 1 shows the compositions of the obtained magnet materials. Table 2 shows the main phase and the average crystal grain size of each magnet material.

After adding and mixing 2.5% by mass of an epoxy resin to each of the magnetic materials thus obtained, compression molding was performed under a pressure of 1200 MPa, and a curing treatment was further performed at a temperature of 150 ° C. for 2.5 hours to obtain a bond. A magnet was made. Table 2 also shows the obtained coercive force, residual magnetic flux density, and maximum magnetic energy product of each bonded magnet.

Comparative Example 1 An alloy ingot produced in the same manner as in the above example was pulverized so that the average particle size was about 4 to 5 μm. X-ray diffraction of the obtained alloy powder revealed that Th ₂ Ni
It was confirmed that the type ₁₇ crystal phase was the main phase.

Next, the above alloy powder was subjected to a nitriding treatment under the same conditions as in the example without performing a heat treatment using hydrogen. Using the obtained magnet material, a bonded magnet was produced in the same manner as in the example. Tables 1 and 2 also show the composition of the magnet material, the main phase and the average crystal grain size, the coercive force of the bonded magnet, the residual magnetic flux density, and the maximum magnetic energy product.

Comparative Example 2 An alloy ingot manufactured in the same manner as in the above example was used.
After being melted by high frequency induction heating in an Ar atmosphere, a molten metal was sprayed from a nozzle onto a metal roll rotating at a peripheral speed of 40 m / s to produce a quenched ribbon. After the quenched ribbon was heat-treated in an Ar atmosphere at 750 ° C for 30 minutes, the average particle size was 4 to 5
It was pulverized to about μm. X of the obtained alloy powder
As a result of the line diffraction, it was confirmed that the TbCu ₇ type crystal phase was the main phase.

Next, the above alloy powder was subjected to a nitriding treatment under the same conditions as in the example. Then, using the obtained magnet material, a bonded magnet was produced in the same manner as in the example. Composition of magnet material, main phase and average grain size, coercive force of bonded magnet,
Tables 1 and 2 show the residual magnetic flux density and the maximum magnetic energy product.
It is described together.

Comparative Example 3 An alloy ingot produced in the same manner as in the above-described example was pulverized so that the average particle size was about 4 to 5 μm. When X-ray diffraction of the obtained alloy powder was performed, Th ₂ Zn
It was confirmed that the type ₁₇ crystal phase was the main phase.

Next, the alloy powder was subjected to a heat treatment using hydrogen and a nitriding treatment under the same conditions as in the example.
Using the obtained magnet material, a bonded magnet was produced in the same manner as in the example. The main phase of the magnet material of Comparative Example 3 is Th ₂ Z
It was an n ₁₇ type crystal phase, and the volume occupancy of the Th ₂ Ni ₁₇ type crystal phase was 3%. Tables 1 and 2 also show the composition of the magnet material, the main phase and the average crystal grain size, the coercive force of the bonded magnet, the residual magnetic flux density, and the maximum magnetic energy product.

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[Table 1]

[0067]

[Table 2]

As is evident from Table 2, the bonded magnets according to the examples are the same as the bonded magnet of Comparative Example 1 which has not been subjected to the heat treatment using hydrogen and the alloy having the Th ₂ Zn ₁₇ type crystal phase as the main phase. It can be seen that both the coercive force and the residual magnetic flux density are superior to the bonded magnet of Comparative Example 3 subjected to the HDDR treatment. In particular, the coercive force has increased to about two to three times. Further, the bond magnets according to Examples 6 to 8 containing a small amount of B have excellent resilience and large maximum energy products because of excellent tissue uniformity and the like. The bonded magnet of Comparative Example 2 having a TbCu ₇ type crystal phase as a main phase produced by a super-quenching method is almost equivalent to Examples 1 to 5 from the viewpoint of the maximum magnetic energy product, but has a coercive force of Example 1. It is as small as 30-40% of ~ 5.

Examples 9 to 13 High-purity raw materials were mixed at a predetermined ratio, and were subjected to high-frequency melting in an Ar atmosphere to produce mother alloy ingots.
Then, each of these master alloy ingots was vacuumed at 1100 ° C ×
After heat treatment for 48 hours, each was pulverized in an Ar atmosphere by a ball mill such that the average particle size became about 4 to 5 μm. X-ray diffraction of each mother alloy confirmed that the main phase was a Th ₂ Ni ₁₇ type crystal phase.

Next, each alloy powder was placed in a heat treatment furnace, and the inside of the furnace was evacuated to a vacuum of 2 × 10 ⁻³ Pa. Then, the temperature was raised to 730 ° C. while flowing 1 atm of H ₂ gas into the furnace. Hold at that temperature for 30 minutes. Next, evacuation was performed again, and after the degree of vacuum reached 2 × 10 ⁻³ Pa, the temperature was raised again to 800 ° C. Then put 1 in the furnace
Each powder was rapidly cooled by flowing Ar gas at atmospheric pressure. X-ray diffraction of each of the obtained alloy powders was performed to determine the volume occupancy of the main phase and the Th ₂ Ni ₁₇ type crystal phase.

Next, in order to make each of the above alloy powders contain nitrogen, each alloy powder was heated at 450 ° C. in a nitrogen gas at 1 atm.
Heat treatment was performed under the conditions of × 25 hours. This nitriding increased the mass of each material by 3.0 to 3.9%. Table 3 shows the composition of the obtained magnet material, and Table 4 shows the volume occupancy and the average crystal grain size of the main phase, the Th ₂ Ni ₁₇ type crystal phase.

After adding and mixing 2.5% by mass of an epoxy resin to each of the magnetic materials thus obtained, compression molding was performed under a pressure condition of 1200 MPa, and a curing treatment was further performed at a temperature of 150 ° C. for 2.5 hours to obtain a bond. A magnet was made. Table 4 also shows the obtained coercive force, residual magnetic flux density, and maximum magnetic energy product of each bonded magnet.

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[Table 3]

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[Table 4]

As is clear from Table 4, by adjusting the composition of the mother alloy, it is possible to obtain magnet materials having various crystal phases as main phases. Further, it can be seen that the magnet material having any of the crystal phases as the main phase has excellent magnet properties.

[0076]

As described above, according to the present invention, T
An HDDR treatment is applied to the mother alloy having the h ₂ Ni ₁₇ type crystal phase as a main phase, and the metal structure of the magnet material containing the Th ₂ Ni ₁₇ type crystal phase as an essential component has a fine recrystallized structure. It is possible to provide a magnet material having magnetic properties. By using such a magnet material, a high-performance bonded magnet can be provided.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masaki Okamura 8 Shinsugita-cho, Isogo-ku, Yokohama, Kanagawa Prefecture Inside the Toshiba Yokohama Office (72) Keisuke Hashimoto 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa (72) Inventor Takahiro Hirai, Inc.8, Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside the Toshiba Yokohama Office (72) Hideki Yamamiya, 8-8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa F-term in Toshiba Yokohama Office (reference) 4K018 AA12 AA27 BA06 BA18 BB04 BC10 BC19 GA04 KA46 5E040 AA04 BB00 CA01 NN01

Claims (13)

[Claims] 1. The general formula: {(R ¹ _X R ²¹ _1-X ) _Y B
_Z T _{1 -YZ} ｝ _{1 -Q} N _Q (wherein, R ¹ is at least one element selected from rare earth elements, R ² is at least one element selected from Zr, Hf, Ti and Sc, T represents at least one element selected from Fe and Co, and X, Y, Z and Q each represent 0.5 ≦ X <1, 0.05 ≦ Y ≦ 0.2, 0 ≦ Z ≦ 0.
1. A magnet material having a composition represented by the following formula: 0.1 ≦ Q ≦ 0.2) and containing 5% by volume or more of a Th ₂ Ni ₁₇ type crystal phase, and having an average crystal grain size of 0.02 to A magnetic material having a range of 50 μm. 2. The magnetic material according to claim 1, wherein the magnetic material has a recrystallized structure due to absorption and desorption of hydrogen. 3. The magnetic material according to claim 1, wherein the mother alloy having a Th ₂ Ni ₁₇ type crystal phase as a main phase has a recrystallized structure in which hydrogen is absorbed and desorbed and recrystallized. And the magnet material. 4. The magnet material according to claim 1, wherein the magnet material has a recrystallized structure having an average crystal grain size in a range of 0.02 to 1 μm. 5. The magnetic material according to claim 1, wherein the magnetic material contains 50% by volume or more of the Th ₂ Ni ₁₇ type crystal phase. 6. The magnetic material according to claim 1, wherein the Th ₂ Ni ₁₇ type crystal phase, the Th ₂ Zn ₁₇ type crystal phase, and Tb
A magnet material comprising a Cu ₇ type crystal phase or a ThMn ₁₂ type crystal phase as a main phase. 7. The magnetic material according to claim 1, wherein Z indicating the boron content ratio satisfies 0 <Z ≦ 0.1. 8. The magnet material according to claim 1, wherein Z representing the boron content ratio satisfies 0.005 ≦ Z ≦ 0.05. 9. The magnet material according to claim 1, wherein 50% by atom or more of the R ¹ element is Sm. 10. The method according to claim 1, wherein:
3. The magnetic material according to claim 1, wherein 50 atomic% or more of the T element is Fe. 11. The magnet material according to claim 1, further comprising: V, Cr, Mo, W, Mn, Ga, Al, S
A magnet material comprising at least one M element selected from n, Ta, Nb, Si and Ni, wherein at least 20 atom% of the T element is replaced by the M element. 12. The magnetic material according to claim 1, further comprising at least one X element selected from H, C, and P, wherein 50% by atom of the N element. A magnet material, wherein the following is substituted with the X element. 13. A bonded magnet, comprising a mixture of the magnet material according to claim 1 and a binder, wherein the mixture has a magnet-shaped compact.