JP2739860B2 - MAGNETIC MATERIAL, MAGNET COMPRISING THE SAME, AND PROCESS FOR PRODUCING THEM - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to samarium (Sm) -iron (Fe) -nitrogen (N)-
The present invention relates to a magnetic material having a hydrogen (H) -oxygen (O) -M component system composition, and more particularly to a magnetic material suitable as a permanent magnet material, a magnet comprising the same, and a method for producing the same.

[Prior art] Permanent magnet materials are used for home appliances, audio products and automobile parts as small motors and actuator materials, while they are widely used in various fields of electronics such as large magnets for medical equipment. is there. Regarding magnet materials, miniaturization and weight reduction are the direction of progress in any use method, and even now, there is a large conversion to Nd-Fe-B magnets consisting of Sm-Co magnets and having high magnetic properties .

The magnetic characteristics here are the saturation magnetization (4πIs) of the material,
Residual magnetic flux density (Br), intrinsic coercive force (iHc), magnetic anisotropy energy, squareness ratio (Br / 4πIs), maximum energy product [(BH) _max ], Curie temperature, thermal demagnetization rate.

By the way, the Sm-Co system has a limit in the supply amount of Sm itself, besides the raw material price, and even now the production volume is almost saturated, and this is also the conversion to the Nd-Fe-B system. It is also the cause of pushing further.

This Nd-Fe-B based magnet (for example, JP-A-59-46008)
Has a great advantage in that it has unprecedented high magnetic characteristics, and is more stable and cheaper in material supply than Sm-Co-based materials. However, on the other hand, the temperature characteristics are poor, the Curie point is low, and the corrosion resistance is poor, which is a major disadvantage.

In order to improve this point, a method of partially replacing Fe with Co (for example, JP-A-59-132104) and a method of partially replacing Nd with heavy rare-earth elements have been proposed (for example, JP-A-59-132104).
60-34005).

However, none of these solutions has essentially solved the problem, and at present, it is an essential condition for practical use to improve the corrosion resistance by coating or plating. For this reason, the practical characteristics are deteriorated, and the original high magnetic characteristics of the Nd—Fe—B system cannot be fully extracted.

That is, although both Sm-Co-based and Nd-Fe-B-based magnet materials are excellent, they have many problems in practical use, and the appearance of new magnet materials is desired.

In addition, in the case of the conventional Sm-Co-based and Nd-Fe-B-based sintered magnets, in any case, a phase having a composition different from that of the inside of the particles is separated at the ferromagnetic particle boundary by heat treatment after sintering. A so-called two-phase separation type microstructure is formed. This weakens the interaction inside the grains, i.e. between the magnetic domains, which in turn improves the magnetic properties.

It is also known that in the Nd-Fe-B system, coercive force and magnetic anisotropy are hardly developed without this heat treatment step.

On the other hand, a Re-Fe-N magnetic material has been proposed as a new rare earth magnetic material. (For example, European Patent Publication EP03
This material has a rhombohedral or hexagonal crystal structure having a 2-17 composition, high magnetization, high anisotropic magnetic field and Curie point, and has the above-mentioned Sm-Co and Nd- It is expected as a magnetic material that compensates for the disadvantages of Fe-B based magnetic materials.

However, when this material is applied to various magnet materials, it is difficult to say that its magnetic properties such as coercive force and squareness and its stability are sufficient.

As a material having a Re-Fe-N composition, JP-A-60-131949
In addition, the M component is added to this and Re
Examples of the -Fe-M-N based material include JP-A-60-144906, JP-A-60-144907, JP-A-62-136551,
These are disclosed in JP-A-62-177101 and JP-A-62-269303. Further, a material having a Re-Fe-M-N-H-O composition is disclosed in JP-A-61-9551 (M = Pd, Ge).

However, Re-Fe-N disclosed in each of the aforementioned publications
In the (-MHO) -based material, only the content of each component element is specified, and the crystal structure and microstructure are not specified. Further, according to the disclosure of the above-mentioned publication, these magnetic materials melt each component element and their nitride,
Since it is manufactured by sintering or heat treatment at a high temperature (700 to 1100 ° C.) that cannot maintain a ferromagnetic crystal structure, iron nitride, α-iron, rare earth nitride, M, and M And a phase having a rhombohedral or hexagonal crystal structure having a 2-17 composition does not exist.

Therefore, magnetic properties such as coercive force often deteriorate rather than improve.

[Problems to be Solved by the Invention] The present invention provides a samarium-iron-nitrogen-oxygen-hydrogen-based magnetic anisotropic material by adding an M component to provide high properties as a bulk magnet, particularly a sintered magnet and a bonded magnet. Consider drawing out, not only specifying the content of each element constituting the magnetic material, its crystal structure consists of 2-17 structure,
Furthermore, by specifying the two-phase separation type as a microstructure,
An object of the present invention is to provide a samarium-iron-nitrogen-hydrogen-oxygen-M component magnetic material having a high coercive force and a squareness ratio and a method for producing the same.

[Means for Solving the Problems] Magnetic Material Sm _α Fe _{(100-α-β-γ-δ-ε)} N _β H
_{In γ} O _δ M _ε , a magnetic material having a two-phase separation type microstructure such as that found in Sm-Co and Nd-Fe-B systems can be obtained even if a heat treatment or an atmosphere treatment is performed in a composition not containing M. It is difficult to prepare. Therefore, it is difficult to bring out high magnetic properties as a bulk such as a sintered magnet.

Therefore, the present invention has solved the above-mentioned problem by adding a metal element, a metalloid element, and an inorganic compound to an Sm-Fe-N-HO-based magnetic material.

That is, the constitution of the present invention is as follows: (1) General formula Sm _α Fe _{(100-α-β-γ-δ-ε)} N _β
H γ _O δ M is a magnetic material represented by _epsilon, M is Mg, Ti, Zr, Hf, Cu, Zn, Al, Ga, In, Si, Ge,
Sn element and at least one of oxides, fluorides, carbides, nitrides, and hydrides of these elements, α, β, γ, δ, and ε are each represented by mol percentage as 5 ≦ α ≦ 20 5 ≦ β ≦ 25 0.01 ≦ γ ≦ 5 0.01 ≦ δ ≦ 10 0.1 ≦ ε ≦ 40, wherein the phase containing Sm, Fe and N has a 2-17 structure, (2) a magnetic material, 3. The magnetic material according to claim 1, wherein the range of δ is 0.6 ≦ δ ≦ 10. (3) The component of the magnetic material according to any one of (1) to (2). A magnetic material having a composition in which 0.01 to 50 mol% of Fe is substituted with Co, (4) a magnetic material comprising the magnetic material according to any one of claims (1) to (3), Has a phase with a high content of M among the components represented by the above general formula at the grain boundary of the microstructure, and has a low content of M or a content of M in the center of the particle. (5) The magnetic material according to any one of claims (1) to (3) or the bulk magnet according to claim (4). (6) Sm, Fe, N, H magnetic material or Fe
By adding the M component to the material in which 0.01 to 50 mol% is replaced with Co and pulverizing, or by pulverizing and adding the M component and sintering it at 200 to 650 ° C., The method for producing a two-phase-separated bulk magnet according to claim 4, wherein the component is mainly diffused at a particle boundary and reacted.

Here, the 2-17 structure mentioned above refers to a Th ₂ Zn ₁₇ type rhombohedral or a Th ₂ Ni ₁₇ type hexagonal crystal. For example, reference Han
dbook on the Physics and Chemistry of Rare-Earths,
Volume 2-Alloys and Intermetallics (North-Holland
Publishing Company, 1979) on page 6
It has been shown that a 2-17 composition alloy has a crystal structure of Th ₂ Zn _17- type rhombohedral or Th ₂ Ni _17- type hexagonal, but which of these structures is mainly determined by the type of rare earth Depends on

As the method of mixing the M component, the method of mixing during sintering or pulverization before annealing is most effective. According to this addition method, the ferromagnetic particle boundary after sintering and the internal two phase It has been clarified that since a separated microstructure can be produced extremely efficiently and uniformly, magnets having various magnetic properties can be prepared by controlling the sintering conditions and the type of the M component to be mixed.

At the time of casting of the master alloy, the M component can be added to the main phase having a 2-17 structure so as to coexist.

That is, the configuration of the production method of the present invention is Sm, Fe or
By adding and sintering a magnetic material composed of Fe + Co, N, H, and O at the time of pulverization before sintering or at the time of sintering, the M component is mainly used as a ferromagnetic particle boundary. A method for producing a two-phase separation type bulk magnet characterized by diffusing or further reacting a part, and mixing and adding an M component during synthesis of a master alloy.
-Fe-N-HOM magnetic material.

 Hereinafter, the former manufacturing method will be described in detail.

When the magnetic powder is composed of only Sm-Fe-N-HO of the components of the present magnetic material, although good magnetic properties are obtained as the powder, it is sintered and subjected to heat treatment. Also Sm-F
In the eN-HO system, the effective phase separation observed in the Sm-Co system and the Nd-Fe-B system does not occur. However, when the M component is added to this system, the M component penetrates into the region between the ferromagnetic particles and plays a role of providing a separation layer between the main phases according to the sintering conditions.
Alternatively, it further reacts with the main phase to form a low magnetic characteristic region.

In particular, when at least one low-melting element Ml having a melting point of 500 ° C. or less is contained as the M component, it is effective to form a low magnetic characteristic region.

However, element Mh with a melting point of 500 ° C or higher, or inorganic compound M
Even when i is added, the same effect can be obtained by finely dispersing between ferromagnetic particles.

Of course, this M component is effective as long as it causes phase separation by heat treatment in the Sm-Fe-N-HOM system, and as described later, at the time of synthesis of the mother alloy or at the stage of nitriding and hydrogenating. The method of adding is also effective.

As described above, the Sm-Fe-N-HOM-based magnetic material can be clearly distinguished from the case where the M component is not contained, and particularly in a sintered magnet, the coercive force and the squareness are significantly improved.

Hereinafter, the composition of the permanent magnet material of the present invention will be described in detail.

In the present invention, the content of the corner composition is represented by mole percentage. The mole percentages α, β, γ, δ, and ε here are M
Is a single element or a multi-element system of two or more elements,
Synonymous with atomic percentage, but when M contains an inorganic compound such as an oxide or a nitride, the sum of the atomic weights of the atomic groups determined by the chemical formula or the composition formula is 1 mol, and Sm, Fe, N, H,
The mole percentage is calculated on the assumption that each atom of the O system is one mole.

Further, as described above, the Sm-Fe-N-HOM of the present invention is used.
One of the features of the magnetic material is the two-phase separation type microstructure, so that the composition fluctuates at the ferromagnetic particle boundary in the microstructure and inside the particle. Therefore, the term “composition” as used herein refers to the average composition of all the microstructures, and there is no limitation on the composition variation in the microstructure due to the processing conditions.

Sm in the present invention needs to be in the range of 5 to 20 mol%. If it is less than 5 mol%, the coercive force will be small, and if it exceeds 20 mol%, the residual magnetic flux density will be small, so that it will not be a practical permanent magnet. Further, 50 atom% of Sm in the present invention may be replaced with another rare earth element.

Fe is the basic composition of this magnetic material, and its content is 90 mol%
Valid up to. Further, when the Fe component is replaced with a Co atom, if the substitution is made up to 50 mol% of Fe, physical properties are not impaired, and specific physical property values can be derived according to the composition and processing conditions.

Note that these Sm-Fe compositions may be based on several structures, such as 2-14 and 2-17 compositions,
In particular, it is preferable to add nitrogen, hydrogen, oxygen, and M based on the 2-17 structure in terms of magnetic properties.

Nitrogen needs to be from 5 to 25 mol%. If it is less than 5 mol% or more than 25 mol%, the magnetic anisotropy decreases,
The coercive force also decreases, and is not practical as a permanent magnet material.
Particularly, the range of 10 to 20 mol% is preferable.

Hydrogen needs to be 0.01 to 5 mol%. In a composition region other than this, the magnetic properties are generally deteriorated and the α phase of iron is easily precipitated. This is also especially 0.02
The range of ４4 mol% is preferred.

As for oxygen, the magnetic properties are generally high when the oxygen content is 0.01 to 10 mol%. In particular, when the oxygen content is adjusted to 0.6 to 10 mol% as shown in Examples, a magnetic material having excellent coercive force and squareness ratio can be obtained.

As the M component, Mg, Ti, Zr, Hf, Cu, Zn, Al, Ga,
It suffices that at least one of In, Si, Ge, and Sn elements and oxides, fluorides, carbides, nitrides, and hydrides of these elements be present, and a coexistence system of two or more kinds is effective. As inorganic compounds, MgO, Al ₂ O ₃ , ZrO ₂ , TiO, Ti ₂
O ₃ , oxides such as rare earth oxides, AlF ₃ , ZnF ₂ , SnF ₂ , Pb
F ₂ , HfF ₄ , fluorides such as rare earth fluorides, SiC, TiC, Zr
C, Mg ₂ C ₃ , HfC, carbides such as rare earth carbides, AlN, Si
_{3 N 4, Zn 3 N 2} , InN, GaN, Ge 3 N 4, Sn 3 N 2, TiN, Mg 3 N 2, Hf
N, nitrides such as rare earth nitrides, and hydrides such as ZrH ₂ , GeH, GeH ₂ , and rare earth hydrogen compounds. The composition can be considered from 0.1 to 40 mol%, but if it is 30 mol% or more, the magnetization tends to decrease in any of the M components, and the coercive force tends to increase, making it a magnetic material for special applications. If it exceeds 40 mol%, this tendency is further strengthened and is not substantial for a permanent magnet. If less than 0.1 mol%, the addition effect is hardly observed.

As described at the beginning of this section, in the microstructure of, for example, a sintered magnet obtained by the present invention, a phase having a distinctly different composition exists between a grain boundary portion of ferromagnetic particles and a grain. Particularly, in a sample having high magnetic properties, the M component is large in the grain boundary portion, and the concentration is low in the grain. This microstructure is very useful for developing and improving magnet properties.

Therefore, the sample composition of the present invention has a two-phase type in which a low concentration part is particularly present in the central part of each ferromagnetic particle, and a high concentration part is present in the ferromagnetic particle surface and the grain boundary part. Mean microstructure average.

The type of the M component and the microstructure of the two-phase separated bulk magnet will be described in more detail.

As described above, except for the radioactive element as the M component and some metal elements of the group VIII, the addition of any element and their inorganic compounds as long as they are non-magnetic, mainly improves the squareness ratio and the coercive force. To contribute. However, the effect on the magnetic properties and the microstructure of the bulk magnet differ depending on the type of the added M component.

Low melting element Ml such as Zn, Ga, Sn, In etc. as M component
When added, Ml easily diffuses into the grain boundaries of ferromagnetic particles by heat treatment at a temperature equal to or higher than the melting point of Ml during sintering,
A two-phase-separated bulk magnet having high magnetic properties can be obtained.

Furthermore, a case where a substance that forms many compounds with iron, such as Zn, Ga, and Sn, is mainly added, and a case that a compound that is mainly iron and hardly forms a stable compound, such as In, is mainly added. Then the effect of the addition is different. However, in any case, characteristics that can be called a permanent magnet material can be imparted by optimizing processing conditions such as sintering.

When two or more alloys or mixtures of low-melting elements such as In-Ga, Ga-Zn, and Sn-Zn are used, the melting point changes in many cases, so high magnetic properties are obtained even at lower temperatures. In some cases, it can be granted. Further, even in the case of a combination of high-melting-point metals such as a La-Cu alloy having a eutectic point composition, the melting point is reduced, so that it may be possible to treat the same as Ml. Also,
Although it can be added as an M component even in a multi-component system such as In-Zn that separates phases at room temperature, the change in magnetic properties due to the addition ratio may be different from the above-mentioned multi-component system and may exhibit a specific behavior.
Care must be taken in optimizing the sintering conditions.

When the high-melting element Mh and the inorganic compound Mi are added as the M component, a bulk magnet having a two-phase separation type microstructure can be obtained by finely dispersing the particles at the grain boundaries of the ferromagnetic particles. Contributes to the improvement of coercive force. Especially in the addition system of Mh and Mi, Ge, Al, Zr, Ti, Si,
Hf, MgO, Al ₂ O ₃ , AlF ₃ , ZnF ₂ , SiC, TiC, AlN, Si ₃ N ₄ ,
When Zn ₃ N ₂ or the like is used as the M component, a high squareness ratio and a high coercive force can be imparted. Pulverized or fine powder adjustable and stable M such as Si, MgO, Al ₂ O ₃ , Si ₃ N ₄ , SiC, TiC
The h and Mi components are particularly effective because they tend to be finely dispersed at the grain boundaries of ferromagnetic particles, and provide high magnetic properties. Also, Cu, Zr
Mh and Mi such as H ₂ is allowed to impart a high residual magnetic flux density.

These high melting element Mh and inorganic compound Mi can be used in combination of two or more.

Further, a combination of the low melting element Ml with the high melting element Mh or the inorganic compound Mi is particularly effective. Zr-Zn, C
Ml-Mh based materials such as u-Zn, Si-Zn, Ge-Zn, Hf-In, MgO-Zn, Al
_{F 3 -Zn, TiC-Zn,} Mi-Ml systems such as Si ₃ N ₄ -Zn, further Ml-M
When a multi-element system such as an h-Mi system is used as the M component, a sintered magnet having high magnetic properties and a two-phase separation type microstructure with good dispersibility of the M component at the grain boundaries of ferromagnetic particles can be obtained. Can be

In the high melting point element Mh, Al, Zr, Si, Ti
For example, when a substance that forms many compounds or a solid solution with iron, such as, for example, is mainly added, and when a substance that is difficult to form a stable compound with a composition mainly composed of iron, such as Cu, is mainly added, The effect is different. However, in any case, characteristics that can be called a permanent magnet can be imparted by optimizing processing conditions such as sintering.

<Production Method> Next, a method for producing the magnetic material of the present invention will be described, but this is not particularly limited.

 FIG. 1 shows a flowchart of this manufacturing method.

That is, (1) In the synthesis of the master alloy, a samarium-iron-based alloy is synthesized, but at this stage, the M component may be added.
In this case, although the magnetic flux density of the magnetic powder after nitriding and pulverization tends to decrease, mainly the squareness ratio and the coercive force are improved. (2)
The magnetic material powder of the present invention can be produced by coarse pulverization, (3) nitriding, and hydrogenation. However, there is also a method in which the M component is not contained at the stage so far and is added only in the next (4) pulverization,
In this method, it is possible to add an M component having high decomposability and sublimability, which is particularly effective. Further, in the step (4), the amount of oxygen can be controlled, thereby changing the characteristics of the magnetic powder. After the magnetic field orientation and molding, a sintered magnet can be produced only by (5) sintering. Further, magnetization is performed to complete the permanent magnet process. A bonded magnet can also be manufactured using the magnetic powder obtained after the step (4).

 The following describes each process in detail.

(1) Synthesis of mother alloy The raw material alloy can be produced by a high-frequency furnace or an arc melting furnace, or by a liquid quenching method. Its composition is Sm 5-5
It is preferred that 25 mol% and Fe are in the range of 75 to 95 mol%. If Sm is less than 5 mol%, a large amount of α-Fe phase is present in the alloy, and a high coercive force cannot be obtained. If Sm exceeds 25 mol%, a high residual magnetic flux density cannot be obtained. The M component can also be added to the alloy at this stage at the same time.

When a high-frequency furnace and an arc melting furnace are used, Fe tends to precipitate when the alloy is solidified from a molten state, which causes a decrease in magnetic properties, particularly coercive force. Therefore, it is effective to perform annealing for the purpose of eliminating the phase of Fe alone and making the composition of the alloy uniform and improving the crystallinity. The effect is remarkable when this annealing is performed at 800 ° C. to 1300 ° C. The alloy produced by this method has good crystallinity and a high residual magnetic flux density as compared with a liquid quenching method or the like.

Even with alloy manufacturing methods such as liquid quenching method and roll rotation method,
An alloy having a desired composition can be produced. In addition, the crystal grains of the alloy produced by these methods are fine, and submicron particles can be prepared depending on the conditions. However, when the cooling rate is high, the alloy becomes amorphous, and the residual magnetic flux density and the coercive force do not increase as much as other methods even after nitriding or hydrogenating. Also in this case, post-treatment such as annealing is necessary.

The master alloy is 300-500 regardless of the method used to form the alloy.
Contains about ppm of oxygen. This level of oxygen content at this stage is what is introduced in the normal operation performed in the process.

(2) Coarse pulverization The pulverization at this stage may be a method of preparing only coarse powder such as a jaw crusher or a stamp mill, or a ball mill or a jet mill depending on the conditions. However, this pulverization is for uniformly performing nitriding and hydrogenation in the next stage, and has sufficient reactivity in accordance with the conditions, and is prepared in a powder state in which oxidation does not remarkably progress. This is very important.

The mixing of the M component can be performed at the time of this pulverization.

The amount of oxygen contained in the material after the coarse pulverization is 1000 ppm or less without much difference from the mother alloy.

(3) Nitriding and hydrogenation As a method for compounding or impregnating nitrogen and hydrogen in the pulverized raw material mother alloy, the raw material alloy powder is pressurized or heated in an ammonia gas or a reducing mixed gas containing an ammonia gas. The method is effective. The amounts of nitrogen and hydrogen contained in the alloy can be controlled by the mixed component ratio of the mixed gas containing ammonia gas, the heating temperature, the pressure, and the processing time.

As the mixed gas, any one of hydrogen, helium, neon, nitrogen, and argon, or a mixture of two or more of them and ammonia gas is effective. The mixing ratio can be changed in relation to the processing conditions, but as the ammonia gas partial pressure,
Especially 0.02-0.75atm is effective, processing temperature is 200-65
A range of 0 ° C, particularly 200 to 500 ° C, is preferred. At low temperatures, the penetration rate is low, and at temperatures above 650 ° C, iron nitrides are formed, and the magnetic properties deteriorate. In the pressure treatment, the contents of nitrogen and hydrogen can be changed even with a pressure of about 10 atm.

When a gas other than ammonia gas is used as a main component in the nitriding or hydrogenating atmosphere, the reaction efficiency is significantly reduced. However, if a long-term reaction is performed using a mixed gas of hydrogen gas and nitrogen gas, nitrogen and hydrogen can be introduced.

The nitridation and hydrogenation steps are performed in a low oxygen partial pressure, but the amount of oxygen at the end of the steps is slightly increased to about 1000 ppm.

(4) Finely pulverized In the Sm-Fe-N-HOM-based magnetic material, the most remarkable effect of the addition of M is that the M component is added and mixed at this stage following nitriding and hydrogenation. This is a method of sintering.

The amount of addition can be seen from the small amount of about 0.1 mol% to 40 mol%, and the addition effect according to each amount can be seen. Especially 2 mol% ~
In the range of 20 mol%, the M component has magnetic properties, especially (B
H) Effective for improving the max value. 0.1 to 2 mol%
In the range, the decrease in the residual magnetic flux density is small and the coercive force is slightly higher than that of the raw material powder.

On the other hand, at about 20 mol% to 30 mol%, a magnet having relatively excellent coercive force and squareness can be obtained, but the residual magnetic flux density becomes low. At 30 to 40 mol%, the coercive force becomes extremely large, but the magnetization is small, and it is a special magnet material. If it exceeds 40 mol%, it is not practical.

Mixing and pulverizing with a ball mill is the most effective method for fine pulverization, but mixing and pulverization can be performed with a method such as a cutter mill or a jet mill. At this time, the mixing and pulverizing conditions significantly affect the final magnet properties. That is, at this stage, the magnetic powder mixes with the M component, and at the same time, the particle diameter and morphology change. Therefore, the microstructure after the component M is diffused is affected by the processing conditions at this stage.

The average particle size after pulverization is desirably about several μm to 10 μm. When the average particle diameter reaches submicron, the reaction with the M component occurs too easily at the time of sintering, and the magnetic properties after sintering do not improve much. In addition, submicron particles are easily oxidized and difficult to handle.

On the other hand, when the particle diameter is several tens of μm, since a large number of magnetic domains are aggregated in each particle, the effect of adding the M component is small, and the coercive force is not significantly improved by sintering.

It should be noted that the magnetic properties can be greatly changed even when only a simple heat treatment is performed without performing the next sintering process. Therefore, for example, application to a bonded magnet or the like can be performed using powder that has undergone heat treatment after this stage.

In this pulverizing step, the amount of oxygen contained in the substance changes by controlling the oxygen partial pressure in the atmosphere such as operation in a glove box and operation in air. The amount of oxygen contained in the substance and the state of its existence change depending on the amount of water and oxygen in the solvent used for pulverization, for example, ethanol, water, and other organic solvents. According to the method exemplified above, 10 μ
m can be controlled at a level of 3500 ppm or more.

(5) Sintering Sintering, like other sintered magnets, increases the packing density of the material,
This is performed for the purpose of increasing the residual magnetic flux density and increasing the mechanical strength of the material. The method is similar to a general magnetic anisotropic magnet,
The heat treatment may be performed after the magnetic powder is magnetically oriented in an external magnetic field and formed into a pressed body.

Specific examples of the sintering method include ordinary normal pressure sintering, hot pressing, and HIP.However, in this case, a hot pressing method that improves magnetic properties and does not require a large device such as the HIP method is used. Atmospheric hot press is described.

The magnetic material contains nitrogen, hydrogen, and oxygen, and the magnetic properties change depending on the content and the form of the content. Therefore, it is important to control its content.

As mentioned earlier, in particular NH ₃ -H ₂ mixed gas is effective to control the N, H of the structure. However, 550
When sintering in the temperature range of ℃ or lower, in addition to the above-mentioned atmosphere gas, the amount of N and H in the structure should be controlled even if annealing is performed in vacuum in an inert gas atmosphere such as argon and helium. Is possible. Further, at a temperature of 650 ° C. or more, decomposition proceeds regardless of the atmosphere, an α-Fe phase is precipitated, and the amounts of N and H change considerably from the initial amounts. Therefore, it is desirable to sinter at 650 ° C. or less, preferably 500 ° C. or less, and the pressure of the hot press is 10 ton /
Around cm ² is enough.

The details of the condition largely depend on what is used as the M component. For example, in Zn having a melting point around 420 ° C., the diffusion of Zn to the grain boundary becomes remarkable from around this temperature, but the coercive force and the squareness ratio are not significantly improved by this diffusion alone. However, when added in a large amount such as 30 mol% or more, the coercive force increases but the residual magnetic flux density decreases, and the final (BH) ma
The x value does not increase.

However, when the temperature was further increased, a new reaction phase was also formed at the particle boundary, and optimization of the amount produced resulted in (BH)
The max value is significantly improved.

Magnetization of the sintered magnet and the bond magnet is performed by a commonly used method, for example, an electromagnet that generates a static magnetic field, a condenser magnetizer that generates a pulsed magnetic field, or the like. The magnetic field strength for sufficiently magnetizing is preferably 15 kO
e or more, more preferably 30 kOe or more.

According to the method exemplified above, the permanent magnet material of the present invention can be manufactured.

By the way, it can be said that perfection of the crystallinity of the material and magnetic properties are closely related. In the case of the material of the present invention, the residual magnetic flux density and the magnetic anisotropy are better as the crystallinity is perfect, that is, the disorder in the atomic arrangement is smaller or the number of defects in the crystal is smaller. Therefore, if the crystallinity of the material is increased, the magnetic properties can be further improved. Annealing is preferred as a specific means for increasing crystallinity. Annealing is effective no matter where in the material manufacturing process as shown in FIG.

The temperature and atmosphere of annealing can be variously selected. The annealing temperature of the samarium-iron-nitrogen-hydrogen-oxygen-M component material of the present invention is preferably 100 to 650 ° C. If the temperature is lower than 100 ° C., the effect of annealing is hardly exhibited, and if the temperature is higher than 650 ° C., volatilization of nitrogen and hydrogen in the material tends to occur.
The annealing atmosphere may be any non-oxidizing atmosphere, and is particularly effective in an atmosphere gas containing hydrogen, argon, nitrogen, and ammonia gas or in a vacuum. Further, when annealing is performed at a low temperature of 300 ° C. or less, the effect is obtained even in an oxidizing atmosphere such as the air.

Annealing of the raw material alloy, that is, in the present invention, when performing annealing before introducing nitrogen and hydrogen, the annealing temperature is 500
It is preferably carried out at 1300 ° C. The atmosphere at this time is preferably performed in an inert atmosphere such as argon, in hydrogen, or in a vacuum.

As a method of increasing the crystallinity other than annealing, after absorbing hydrogen in the Sm-Fe-based raw material alloy, finely pulverizing the obtained Sm-Fe-H alloy, and then adding nitrogen and Sm-Fe-H to the Sm-Fe-H. A method of performing a hydrogen / oxygen treatment or a method of performing a nitrogen / hydrogen / oxygen treatment after finely pulverizing by utilizing the fact that the alloy is powdered by repeating hydrogen absorption / desorption to the Sm-Fe-based raw material alloy is mentioned. Can be

In the former, as a method of absorbing hydrogen, at a relatively low temperature, a reducing gas mixture containing H ₂ gas or H ₂ gas (for example, a mixed gas of H ₂ and N ₂ , a mixed gas of H ₂ and Ar, ₂ and He), or in a heated hydrogen gas stream or a reducing gas mixture containing hydrogen gas.

In the latter method, as a method of repeating the occlusion / desorption of hydrogen, for example, a Sm—Fe-based alloy is placed in an H ₂ atmosphere, and the temperature is repeatedly raised and lowered, whereby the occlusion / desorption of hydrogen can be repeated.

It is not clear why the fine powder having good crystallinity can be obtained by the above method, but one of the reasons is that hydrogen penetrates between crystal lattices, so that the energy required for pulverization can be reduced, and as a result, It is considered that the damage to the crystal is reduced. In the case of pulverization by repetition of hydrogen absorption and desorption, it is considered that the crystal is not disturbed because the crystal is not subjected to mechanical shock.

EXAMPLES Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

Example 1 Melting and mixing were performed in a high-frequency furnace in an argon atmosphere using Sm having a purity of 99.9% and Fe having a purity of 99.9%. Then, the molten metal was poured into a mold and cooled, and further in an argon atmosphere having an oxygen partial pressure of about 10 ^-5 atm. By annealing at 1250 ° C for 3 hours,
Sm ₂ Fe with mole percentage of 10.5% Sm and 89.5% Fe
Alloys having a crystal structure of ₁₇ compositions were prepared.

After crushing this alloy in a nitrogen atmosphere with a jaw crusher, the average particle size is furthermore 100 μm by a coffee mill.
To coarsely pulverized.

The obtained alloy powder is placed in a tubular furnace, and at 450 ° C., a mixed gas flow of ammonia gas 0.4 atm and hydrogen gas 0.6 atm is passed through the tubular furnace, and nitrogen and hydrogen enter the alloy powder for 45 minutes. I was sorry.

Subsequently, Sm was gradually cooled to room temperature in the above atmosphere.
An alloy powder having a composition of _8.5 Fe _72.1 N _17.0 H _2.1 O _0.3 was obtained.

This crystal structure was mainly a rhombohedral structure of Th ₂ Zn ₁₇ type.

10 mol% of Zn was added to the alloy powder, and a vibration ball mill was applied for 1 hour to obtain a fine powder having an average particle diameter of 7 μm.

This powder is 1ton / cm ² , 15kOe using a uniaxial magnetic field press.
The magnetic field was formed into a plate of 5 × 10 × 2 mm under the conditions described above, and this was sintered at 470 ° C. for 2 hours in a mixed gas flow of ammonia gas 0.2 atm and hydrogen gas 0.8 atm. However, at the time of sintering 12 ton / cm ²
Pressure was continued to be applied.

The plate-like sintered body thus obtained was magnetized with a pulse magnetic field of about 60 kOe to obtain a sintered magnet having a composition of Sm _7.8 Fe _65.4 N _15.3 H _0.8 O _0.7 Zn _10.0 .

This crystal structure was mainly a rhombohedral structure of Th ₂ Zn ₁₇ type.

The residual magnetic flux density (Br) of this sintered magnet is 9.3 kG, the coercive force (iHc) is 7.0 kOe, (BH) max is 15.5 MGOe, and the squareness ratio (Br / 4
πIs) was 0.915.

Example 2 99.9% pure Sm, 99.9% pure Co and 99.9% pure
Using Fe, the mole percentages are Sm 10.5%, Co 9.0% and F
e An alloy consisting of 80.5% was prepared by arc melting in a water-cooled copper boat under an argon atmosphere with an oxygen partial pressure of about 10 ^-5 atm. The obtained alloy was annealed at 900 ° C. for 36 hours in an argon atmosphere having an oxygen partial pressure of about 10 ⁻⁵ atm. The obtained alloy was roughly pulverized with a jaw crusher in a nitrogen atmosphere, and then further pulverized by a coffee mill to an average particle diameter of 100 μm.

The obtained powder is allowed to absorb nitrogen and hydrogen at a reaction temperature of 470 ° C and a reaction time of 60 minutes by flowing a mixed gas flow having a partial pressure of ammonia gas of 0.67 atm and a partial pressure of hydrogen gas of 0.33 atm in a tubular furnace. Was. Subsequently, a powder having a composition of Sm _8.3 Fe _63.1 Co _7.1 N _17.8 H _3.4 O _0.3 was obtained by gradually cooling to room temperature in the above atmosphere.

10 mol% of Zn was added to this alloy powder, and a vibration ball mill was applied for 2 hours to obtain a fine powder having an average particle diameter of 4.6 μm.

This powder was magnetically molded in the same manner as in Example 1, then sintered, magnetized, and Sm _7.6 Fe _57.9 Co _6.5 N _16.3 H _1.1 O _0.6 Z
A sintered magnet having a composition of n _10.0 was obtained.

The residual magnetic flux density (Br) of this sintered magnet is 9.9 kG, coercive force (iHc) is 5.8 kOe, (BH) max is 13.5 MGOe, squareness ratio (Br / 4
πIs) was 0.908.

Examples 3 to 10 and Comparative Example 1 To the Sm _8.5 Fe _72.1 N _17.0 H _2.1 O _0.3 magnetic powder obtained in Example 1, 10 mol% of a low melting point additive Ml (melting point of 500 ° C. or less) shown in Table 1 was added. The mixture was mixed and pulverized in a vibration ball mill for 1 hour. This fine powder was subjected to 1 ton / c by a uniaxial magnetic field press as in Example 1.
It was formed into a 10 × 5 × 2 mm plate under the conditions of m ² and 15 kOe. This was hot-pressed at 470 ° C. and 10 ton / cm ² in a mixed gas atmosphere of ammonia gas 0.2 atm and hydrogen gas 0.8 atm for 2 hours to obtain a sintered magnet. The residual magnetic flux density of these magnets [Br
(KG)], coercive force [iHc (kOe)], (BH) max (MGO
e) and the squareness ratio (Br / 4πIs) are shown in Table 1. However, the molar percentage of O is about 1 mol%.

Examples 11 to 20 and Comparative Example 2 The Sm _8.5 Fe _72.1 N _17.0 H _2.1 O _0.3 magnetic powder obtained in Example 1 was mixed with the high melting point additive Mh or the inorganic compound Mi shown in Table 2 in an amount shown in Table 2. And crushed with a vibrating ball mill for about 1 hour. This fine powder was magnetically molded in the same manner as in Examples 3 to 10, then sintered and magnetized to obtain a sintered magnet.

The residual magnetic flux density [Br (kG)], coercive force [iHc (kOe)], (BH) max (MGOe), squareness ratio (Br / 4πI) of these magnets
Table 2 shows s). However, the molar percentage of O is about 1 mol%.

Examples 21 to 35 and Comparative Example 3 The additives Mh and Ml, Mi and Ml shown in Table 3 were added to the Sm _8.5 Fe _72.1 N _17.0 H _2.1 O _0.3 magnetic powder obtained in Example 1 in the amounts shown in Table 3. The mixture was added and crushed with a vibrating ball mill for about 1 hour. This fine powder was magnetically molded in the same manner as in Examples 3 to 10, then sintered and magnetized to obtain a sintered magnet. The residual magnetic flux density [Br (kG)] and coercive force [iHc (kO
e)], (BH) max (MGOe), squareness ratio (Br / 4πIs)
It is shown in the table. However, the molar percentage of O is about 1 mol%.

Example 36 Oxygen partial pressure of about 10 ⁻⁵ atm using Sm, Fe, and Zn having a purity of 99.9%
The mixture was melted and mixed in a high-frequency melting furnace in an argon atmosphere, cooled by pouring the molten metal into a mold, and further annealed in an argon atmosphere at 900 ° C. for 36 hours, so that the mole percentage was 10.6% for Sm, 77.8% for Fe, and 11.6% for Zn. % Was prepared.

This alloy was roughly pulverized to a particle size of about 100 μm in the same manner as in Example 1, then nitrogenated and hydrogenated, and then subjected to a vibration ball mill to obtain a particle size of 6 μm.
Micronized to μm, Sm _8.6 Fe _63.4 Zn _9.4 N _15.2 H _2.7 O _0.7
Was obtained.

Next, this fine powder was magnetically oriented in the same manner as in Example 1, and sintered in a mixed gas flow of ammonia gas 0.2 atm and hydrogen gas 0.8 atm at 470 ° C. and 12 ton / cm ² for 110 minutes.

The residual magnetic flux density (Br) of the obtained sintered magnet was 8.1 kG, the coercive force (iHc) was 5.0 kOe, (BH) max was 10.4 MGOe, and the squareness ratio (Br / 4πIs) was 0.893.

Example 37 and Comparative Example 4 Using Sm having a purity of 99.9% and Fe having a purity of 99.9%, the mixture was melted and mixed in a high-frequency furnace in an argon atmosphere, and then the molten metal was poured into a mold having a width of 3 mm and cooled. ^-5 at
An alloy consisting of 10.5% of Sm and 89.5% of Fe was prepared by annealing at 1030 ° C. for 13 hours in an argon atmosphere of 10 m.

This alloy was roughly pulverized in a nitrogen atmosphere using a coffee mill to an average particle size of 30 μm.

The obtained alloy powder was placed in a tube furnace, and at 450 ° C., a mixed gas flow of ammonia gas 0.4 atm and hydrogen gas 0.6 atm was passed through the tube furnace for 2 hours to perform nitriding / hydrogenation. Annealing was performed in an argon stream at 10 ^-4 atm, followed by slow cooling to obtain an alloy powder having a composition of Sm _8.9 Fe _75.2 N _15.4 H _0.2 O _0.3 .

This alloy powder was classified and adjusted to a particle size of 20 to 38 μm, Zn was added to the alloy powder in an amount of 8 mol%, and a rotary ball mill was applied for 4 hours to obtain a fine powder.

Next, the fine powder is taken out from the pulverizing pot in a glove box through which a nitrogen stream having an oxygen concentration of 1% flows in and out, and placed in a tubular furnace, and annealed at 420 ° C. for 1.5 hours in an argon gas stream having an oxygen partial pressure of 10 ⁻⁵ atm or less. Sm _7.8 F
e _66.8 N _13.9 H _0.05 O _3.5 Zn _8.0 A fine powder A having a composition of _8.0 was obtained.

This powder was formed into a plate of 5 × 10 × 2 mm using a uniaxial press under the conditions of 1 ton / cm ² and 15 kOe, and the formed product was impregnated with a toluene solution of polyisoprene rubber and dried sufficiently. . Next, a pressure of 14 ton / cm ² was applied to this compact to obtain a compacted powder compact bonded magnet.

Residual magnetic flux density [Br (kG)], coercive force [iHc (kOe)], (BH) max (MGOe), squareness ratio (Br / 4πI) of this bonded magnet
s) is shown in Table 4.

Table 4 also shows the magnetic properties of a bonded magnet obtained by similarly forming a magnetic field using the fine powder B obtained by pulverizing in the same manner as the fine powder A without adding Zn. .

Example 38 The fine powder A obtained in Example 40 and a polyamide ester ether elastomer solution having a concentration of 10% by weight dissolved in a mixed solvent of methanol and chloroform were kneaded at an 8: 2 weight ratio, and 15 k
The solution was charged into a mold placed in a magnetic field of Oe, and the solvent was recovered to produce a pellet.

Then, in a nitrogen stream at 200 ° C for 30 minutes, add 10 t
A pressure of on / cm ² was applied to produce a compression-molded bonded magnet.

The residual magnetic flux density (Br) of the obtained compression-molded bonded magnet is
8.6 kG, coercive force was 7.7 kOe, (BH) max was 15.9 MGOe, and squareness ratio (Br / 4πIs) was 0.958.

Example 39 Fine powder A and 6-nylon obtained in Example 37 were kneaded at a weight ratio of 9: 1 in a nitrogen atmosphere at 280 ° C., and cut into pellets having a length of 3 to 5 mm.

The pellets were filled in a 12 mm diameter cylinder having a 2 mm nozzle diameter, then melted at 290 ° C. in an argon atmosphere, and then punched into a mold having a cross section of 10 mm × 5 mm at a pressure of 75 kg / cm ² . At this time, a magnetic field of 4.5 to 6 kOe was continuously applied to the mold.

The residual magnetic flux density (Br) of the obtained injection-molded bonded magnet is
5.6 kG, coercive force was 6.1 kOe, (BH) max was 5.1 MGOe, and squareness ratio (Br / 4πIs) was 0.795.

Comparative Example 5 An Sm-Fe-N-HOM-based sintered magnet was obtained in the same manner as in Example 39 except that the nitriding temperature was changed to 700 ° C.

 The intrinsic coercivity of this magnet was 0.4 kOe.

Further, as a result of analyzing the crystal structure of this material by an X-ray diffraction method, diffraction lines corresponding to α-iron and iron nitride were mainly detected, and diffraction lines corresponding to the Th ₂ Zn ₁₇ structure and the Th ₂ Ni ₁₇ structure were detected. Was not found.

Comparative Example 6 Sm-Fe-N- having an average particle size of about 7 μm obtained in Example 1
The HOM powder was magnetically molded under the conditions of ² ton / cm ² and 15 kOe, and then heat-treated at 1100 ° C. for 1 hour in an argon atmosphere. After quenching this, the intrinsic holding power of the compact is
It was 0.02 kOe.

As a result of analyzing the detection structure of this material by X-ray diffraction, diffraction lines corresponding to α-iron and iron nitride were mainly detected, and diffraction lines corresponding to the Th ₂ Zn ₁₇ structure and the Th ₂ Ni ₁₇ structure were detected. Was not found.

[Effects of the Invention] As described above, according to the present invention, a two-phase-separated bulk magnet having sufficient coercive force, squareness, and saturation magnetic flux density without adding a special process, and a bonded magnet and its material Can be produced.

[Brief description of the drawings]

FIG. 1 is a process diagram illustrating one method for producing a sintered magnet of the present invention.

Continuation of the front page (72) Inventor Akinobu Sudo 2-1, Samejima, Fuji-shi, Shizuoka Prefecture Asahi Kasei Corporation (56) References JP-A-60-131949 (JP, A) JP-A-60-144906 (JP) , A) JP-A-61-9551 (JP, A) JP-A-62-136551 (JP, A)

Claims (6)

(57) [Claims] 1. The general formula Sm _α Fe
A magnetic material represented by _{(100-α-β-γ} -δ-ε) N β H γ O δ M ε, M is Mg, Ti, Zr, Hf, Cu, Zn, Al, Ga, In, Si , Ge, Sn
Elements and oxides, fluorides, carbides of these elements,
At least one of nitrides and hydrides, α, β, γ, δ, and ε are each represented by a molar percentage of 5 ≦ α ≦ 20 5 ≦ β ≦ 25 0.01 ≦ γ ≦ 5 0.01 ≦ δ ≦ 10 0.1 ≦ ε ≦ 40. A magnetic material characterized in that a phase containing Sm, Fe and N has a 2-17 structure. 2. The magnetic material according to claim 1, wherein δ
Is in the range of 0.6 ≦ δ ≦ 10. 3. A magnetic material having a composition in which 0.01 to 50 mol% of Fe, which is a component of the magnetic material according to any one of (1) and (2), is substituted by Co. (4) The magnetic material according to any one of (1) to (3), wherein the content of M among the components represented by the above general formula is large at the grain boundary of the microstructure of the structure. Having a phase,
A two-phase separation type bulk magnet, characterized in that a M content is low or a phase containing no M is present in a particle central portion. 5. A bonded magnet comprising the magnetic material according to any one of (1) to (3) or the bulk magnet according to (4). 6. An M component is added to a magnetic material composed of Sm, Fe, N, H, and O, or a material in which 0.01 to 50 mol% of Fe is replaced with Co, and the mixture is pulverized or pulverized. 5. The method according to claim 4, wherein the M component is added, and the M component is sintered at a temperature of 200 to 650 ° C., whereby the M component is diffused mainly at the grain boundaries and reacted. A method for manufacturing a phase-separated bulk magnet.