JP2705985B2 - MAGNETIC MATERIAL, MAGNET COMPRISING THE SAME, AND PROCESS FOR PRODUCING THEM - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a magnetic material having a rare earth (R) -iron (Fe) -nitrogen (N) -hydrogen (H) -M component composition, and more particularly to a permanent magnet. The present invention relates to a magnetic material suitable as a material, a magnet made of the same, and a method for manufacturing 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 usage, and even now Sm-Co-based magnets are being converted to Nd-Fe-B-based magnets with higher 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, polygon 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 amount 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, Japanese Patent Application Laid-Open No. 59-46008) has unprecedentedly high magnetic properties,
There is a great advantage that the raw material supply is stable and inexpensive compared to the Co system. 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).
No. 60-34005).

However, none of these solutions has essentially solved the problem. 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 lowered, and the original high magnetic characteristics of the Nd—Fe—B system cannot be fully extracted.

In other words, although both Sm-Co and Nd-Fe-B are excellent magnet materials, they have many practical problems.
The emergence of new magnetic materials is also desired.

Further, in the conventional Sm-Co based, Nd-Fe-B based sintered magnet,
In any case, a phase having a composition different from that of the inside of the particles is separated at the boundary of the ferromagnetic particles by the 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 a coercive force and a magnetic anisotropy are hardly developed in the Nd-Fe-B system without this heat treatment step.

On the other hand, as a new rare earth magnetic material, an R—Fe—N magnetic material has been proposed (for example, European Patent Publication 3690).
No. 97). This material has a rhombohedral or hexagonal crystal structure having a 2-17 composition, has a high magnetization, an anisotropic magnetic field, and a high Curie point, and has the above-mentioned Sm-Co and Nd-Fe-B
This is expected as a magnetic material that compensates for the drawbacks of 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 an R-Fe-N composition, JP-A-60-13
1949, and added thereto an M component to add R-
As the Fe-M-N-based material, JP-A-60-144906,
JP-A-60-144907, JP-A-62-136551, JP-A-62-1771
61, and JP-A-62-269303. Further R
As a material having a composition of -Fe-M-N-H, JP-A-61-9551
(M = Pd, Ge, Ag, C, B).

However, the R-Fe-N disclosed in each of the aforementioned publications
In the (-MH) -based material, only the content of each component element is specified, but the crystal structure or microstructure is not specified. Further, according to the disclosure of the above publication, these magnetic materials are prepared by melting and sintering each component element and their nitride, or at a high temperature (700 to 1100 ° C.) at which a ferromagnetic crystal structure cannot be maintained. ), So that iron nitride, α-iron, rare earth nitride, M, and M
And a phase having a 2-17 structure 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 rare earth-iron-nitrogen-hydrogen based novel magnetic anisotropic material of the prior application by adding an M component to provide high properties as a bulk magnet, particularly a sintered magnet and a bonded magnet. Not only specify the content of each element constituting the magnetic material, but also specify the 2-17 structure as the crystal structure, and more preferably specify the two-phase separation type as the microstructure. It is an object of the present invention to provide a rare earth-iron-nitrogen-hydrogen-M component magnetic material having a high coercive force and a high squareness ratio and a method for producing the same.

[Means for Solving the Problems] Magnetic Material R _α Fe _{(100-α-β-γ-δ)} N _β H _γ
In M _δ , heat treatment is performed for a composition containing no M,
Even if the atmosphere treatment is performed, it is difficult to prepare a magnetic material having a two-phase separation type microstructure as seen in Sm-Co and Nd-Fe-B systems. Therefore, it is difficult to obtain 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 R—Fe—N—H-based magnetic material. That is, the constitution of the present invention is as follows: (1) General formula R _α Fe _{(100-α-β-γ-δ)} N _β H _γ
A magnetic material represented by M _δ , R is a rare earth element containing samarium as a main component, M is Li, Na, K, Mg, Ca, Sr, Ba, Ti, Zr, Hf, V,
Nb, Ta, Cr, Mo, W, Mn, Pd, Cu, Ag, Zn, B, Al, G
a, In, C, Si, Ge, Sn, Pb, Bi and these elements and R oxides, fluorides, carbides, nitrides, hydrides, carbonates, sulfates, silicates, chlorides , At least one of nitrates, α, β, γ, and δ are each represented by a molar percentage of 5 ≦ α ≦ 205 ≦ β ≦ 30 0.01 ≦ γ ≦ 10 0.1 ≦ δ ≦ 40, and at least R, Fe and A magnetic material characterized in that the N-containing phase substantially has a 2-17 structure; (2) 0.1% of Fe which is a component of the magnetic material described in (1) above.
A magnetic material characterized by having a composition in which 01 to 50 mol% is substituted with Co; and (3) a magnetic material according to the above (1) or (2), which has a microstructure particle boundary portion of the structure. A phase having a high content of M among the components represented by the above general formula, and a phase having a low content of M or a phase not containing M in the center of the particle. Separated bulk magnet, and (4) a bonded magnet containing the magnetic material described in (1) or (2) above, and (5) a bulk magnet described in (3) above. (6) a magnetic material composed of R, Fe, N, H, or Fe
By adding the M component to the material in which 01 to 50 mol% has been replaced by Co and pulverizing, or by pulverizing and adding the M component and sintering the M component, the (3) The method for producing a two-phase-separated bulk magnet according to (3) above, wherein the M component is mixed and added during the synthesis of the master alloy. (1) The method for producing a magnetic material according to (1) or (2), and (8) the method for producing a bulk magnet according to (3), wherein the M component is mixed and added during the synthesis of the master alloy. And (9) The method for producing a bonded magnet as described in (4) or (5) above, wherein the M component is mixed and added during the synthesis of the master alloy.

The “magnetic material” referred to above is generally a material exhibiting ferromagnetism, but in the present application, particularly, saturation magnetization, residual magnetic flux density, intrinsic coercive force, magnetic anisotropic energy, squareness ratio,
It refers to a magnetic material that is excellent in various magnetic properties such as maximum energy product, Curie temperature, and thermal demagnetization rate and is suitable as a permanent magnet material.

The “bond magnet” refers to a magnet formed by dispersing a magnetic material in a thermoplastic resin or a thermosetting resin and molding the same.

The term "bulk magnet" generally refers to a massive magnet, but in the present application, as exemplified particularly by a sintered magnet, a metal phase or an inorganic phase becomes a boundary phase of magnetic material particles, and forms a bulk as a whole. "Bond magnet" means a magnet
Is not included in the bulk magnet.

If a plurality of magnetic material particles are bound by the M component, they are regarded as “bulk magnets” even if they have an irregular shape such as a granular shape.

For example, a powder in which the M component is bonded to the particles by adding the M component to the magnetic material fine powder and then heat-treated, or a powder obtained by pulverizing a once sintered bulk magnet is also a two-phase separated structure. "Bulk magnet" as long as it is inside the powder
Thus, such a bulk magnet is a magnetic material for bonded magnet applications.

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 H
andbook on the Physics and Chemistry of Rar
e-Earths, Volume 2-Alloys and Intermetallics
(North-Holland Publishing Company, 1979), p. 6 shows that a rare earth-iron 2-17 composition alloy has a Th ₂ Zn ₁₇ type rhombohedral or Th ₂ Ni ₁₇ type hexagonal crystal structure. However, which of these structures is adopted depends mainly on the type of rare earth.

Since more light rare earth such as practical is Sm take Th ₂ Zn ₁₇ structure, Th ₂ Zn ₁₇ of 2-17 structure in the present invention
The structure is preferred.

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.

In addition, the M component can be added to the main phase having the 2-17 structure by adding the M component at the time of casting the master alloy.

That is, the structure of the production method of the present invention is R, Fe or Fe
Addition of the M component at the time of pulverization before sintering or sintering of the magnetic material composed of + Co, N, H, and sintering, the M component is mainly applied to the boundary of the ferromagnetic particles. A method for producing a two-phase separation type bulk magnet characterized by diffusing or further reacting, and R-Fe-N- characterized by mixing and adding an M component at the time of synthesizing a master alloy.
This is a method for manufacturing a bulk magnet or a bonded magnet using an HM magnetic material.

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

When the magnetic powder is composed only of R-Fe-NH of the components of the present magnetic material, good magnetic properties can be obtained as the powder, but even if the powder is sintered and heat-treated, −Fe
In the -NH system, no effective phase separation observed in the Sm-Co and Nd-Fe-B systems occurs. 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, or further reacts with the main phase. A low magnetic characteristic region is formed.

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, even when an element Mh having a melting point exceeding 500 ° C. or an inorganic compound Mi is added, a similar effect can be obtained by finely dispersing the ferromagnetic particles between the ferromagnetic particles.

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

As described above, the R-Fe-NHM-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 mainly remarkably improve.

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

In the present invention, the content of each composition is represented by mole percentage. The molar percentages α, β, γ, and δ here have the same meaning as atomic percentages when M is a single element or a multi-element system of two or more elements, but M is an inorganic compound such as an oxide or a nitride. Is included, the total of the atomic weights of the atomic groups determined by the chemical formula or the composition formula is defined as 1 mole, and the mole percentage is calculated with 1 atom of each of R, Fe, N, and H as 1 mole.

As described above, in the R-Fe-NHM-based magnetic material of the present invention, a two-phase separation type microstructure is one of its features. The composition varies inside the particles. Therefore, the composition here means the average of all the microstructures, and the composition variation in the microstructure due to the processing conditions does not matter.

R in the present invention must 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. R is preferably samarium. However, a rare earth element other than samarium may be present in a small amount as long as the object of the present invention can be achieved.

Further, R may have a purity that can be obtained by industrial production, and it is preferable to use a high-purity raw material.

Fe is the basic composition of this magnetic material, and its content is 90 mol%
Valid up to. In addition, when this Fe component is replaced by a Co atom, if it is replaced by up to 50% by mole of Fe, physical properties are not impaired, and unique physical property values can be obtained depending on the composition and processing conditions. The unique physical property value expected by substituting means mainly the temperature characteristics of magnetic characteristics,
With less than 01 mol% substitution, this improvement effect is hardly seen,
If the substitution exceeds 50 mol%, the residual magnetic flux density decreases, which is not preferable.

In addition, about these R-Fe composition only, 2-14, 2-
Although it is conceivable that the composition is based on several structures such as the 17 composition, nitrogen, hydrogen, M
Is preferred in terms of magnetic properties.

Nitrogen needs to be 5 to 30 mol%. If it is less than 5 mol% or more than 30 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 because various magnetic properties such as coercive force and magnetic anisotropy are high.

Hydrogen needs to be 0.01 to 10 mol%. In a composition region other than this, the magnetic properties are generally deteriorated and the α phase of iron is easily precipitated, and as a result, the coercive force is particularly lowered, which is not preferable. This is particularly preferably in the range of 0.02 to 5 mol%.

As the M component, Li, Na, K, Mg, Ca, Sr, Ba, Ti, Z
r, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Pd, Cu, Ag, Z
n, B, Al, Ga, In, C, Si, Ge, Sn, Pb, Bi elements and these elements and R oxides, fluorides, carbides, nitrides, hydrides, carbonates, sulfates, It is sufficient that at least one of silicates, chlorides, and nitrates is present, and a coexistence system of two or more is effective.

As inorganic compounds, MgO, Al ₂ O ₃ , CaO, ZrO ₂ , TiO,
Oxides such as Ti ₂ O ₃ and rare earth oxides, AlF ₃ , ZnF ₂ , Ca
F ₂ , CrF ₂ , SnF ₂ , PbF ₂ , LiF, SrF ₂ , HfF ₄ , PdF ₃ , AgF,
AgF ₂ , fluorides such as rare earth fluorides, SiC, TiC, Zr
C, WC, TaC, NbC, VC, Mg 2 C 3, Mo 2 C, MoC, HfC, carbides such as rare earth _{carbides, AlN, Si 3 N 4,} Zn 3 N 2, InN, GaN, C
a ₃ N ₂ , Ge ₃ N ₄ , CrN, Sn ₃ N ₂ , W ₂ N ₃ , TaN, TiN, NbN, VN,
Mg ₃ N ₂ , Mo ₂ N, MoN, BN, HfN, nitrides such as rare earth nitrides, ZrH ₂ , CaH ₂ , CrH, CrH ₂ , GeH, GeH ₂ , LiH, strontium hydride, palladium hydride, rare earth Hydrides such as hydrides, MgCO ₃ , SrCO ₃ , BaCO ₃ , CaCO ₃ , MnCO ₃ , L
i ₂ CO ₃ , carbonates such as rare earth carbonates, Ag ₂ SO ₄ , BaSO ₄ , Sr
SO ₄ , CaSO ₄ , K ₂ SO ₄ , sulfates such as rare earth sulfates, sodium silicate, lithium silicate, potassium silicate, zirconium silicate, barium silicate, magnesium silicate, manganese silicate, rare earth silicate Silicates such as salts,
NaCl, KCl, CuCl, PbCl ₂ , BiCl ₂ , AgCl, chlorides such as rare earth chlorides, and nitrates such as KNO ₃ , Al (NO ₃ ) ₃ , AgNO ₃ , and rare earth nitrates are exemplified.

The composition can be considered from 0.1 to 40 mol%, but at 30 mol% or more, the magnetization decreases with any metal,
The tendency of the coercive force to increase becomes remarkable, and it becomes a magnetic material for special applications. If it exceeds 40 mol%, this tendency is further strengthened and is not practical as 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 portion of the M component is present at the center of each ferromagnetic particle, and a high concentration portion is present at the ferromagnetic particle surface and the grain boundary portion. 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 of the metal elements of Group 8, any element and their inorganic compounds can be added to improve the squareness ratio and the coercive force, as long as they are nonmagnetic. 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.

When a low-melting element Ml such as Zn, Ga, Sn, In, Pb, or Bi is added as an M component, heat treatment is performed at a temperature equal to or higher than the melting point of Ml at the time of sintering, so that Ml is added to the grain boundaries of the ferromagnetic particles. Are easily diffused, and a two-layer separated bulk magnet having high magnetic properties can be obtained.

In addition, substances that form many compounds with iron, such as Zn, Ga, Sn, etc., and substances that are difficult to form stable compounds with a composition mainly composed of iron, such as In, Pb, Bi, etc. The effect of the addition is different when mainly added. 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. In some cases, it can be granted. Further, even in the case of a combination of high melting point metals such as an La-Cu alloy having an amorphous point composition, the melting point is lowered, so that it may be possible to treat the same as Ml. In addition, a multi-component system such as In-Zn, which separates phases at room temperature, can be added as an M component.However, a change in magnetic properties depending on the addition amount ratio is different from that of the 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 them at the grain boundaries of the ferromagnetic particles. It contributes to improving the ratio and coercive force. In particular, Ta, Nb, Sm, Cr,
V, W, C, Ge, Al, Ce, Zr, Ti, Mo, Si, Hf, Sm
₂ O ₃ , MgO, Al ₂ O ₃ , AlF ₃ , ZnF ₂ , SiC, TiC, AlN, Si
_{When 3} N ₄ , Zn ₃ N ₂ , SrCO ₃ , BaSO ₄ , Li ₂ SiO ₃ , NaCl, or the like is used as the M component, a high squareness ratio and a coercive force can be provided. Stable Si, Mg with fine grinding or fine powder adjustment
Mh and Mi components such as O, Al ₂ O ₃ , Si ₃ N ₄ , SiC, and TiC are particularly effective because they easily disperse finely at the grain boundaries of ferromagnetic particles, and provide high magnetic properties. Also, Cu, Mo, Pd, ZrH ₂ , Ag ₂ SO ₄ ,
Mh and Mi such as Mg ₂ SiO ₄ , MgCO ₃ and KNO ₃ give high residual magnetic flux densities.

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,
Ml-Mh such as Sm-Zn, Cu-Zn, Si-Zn, Ge-Zn, Hf-In
_{System, MgO-Zn, AlF 3 -Zn} , TiC-Zn, Si 3 N 4 -Zn, Ag 2 SO 4
When a multi-component system such as a Mi-Ml system such as -In or an Ml-Mh-Mi system is used as the M component, a two-phase-separated microstructure in which the dispersibility of the M component is good at the grain boundaries of the ferromagnetic particles. Thus, a sintered magnet having high magnetic properties having the following characteristics can be obtained.

In the high melting point element Mh, Al, Zr, Si, T
a, When mainly adding substances that form many compounds or solid solutions with iron, such as Ti, and when mainly adding substances, such as Cu, which are difficult to form stable compounds with an iron-based composition The effect of addition is different. However, in any case, characteristics that can be called a permanent magnet can be imparted by optimizing processing conditions such as sintering.

Among the inorganic compounds Mi containing oxygen, those which are easily decomposed and strongly oxidize the ferromagnetic phase may have no effect of addition depending on heat treatment conditions such as sintering. However, this does not apply to the case where oxidation occurs to such an extent that the surface of the ferromagnetic particles is covered with a thin oxide film.

Further, among the inorganic compounds Mi containing water of crystallization, those that release oxygen simultaneously with the water of crystallization during heat treatment such as sintering are not preferable because they oxidize the ferromagnetic particles and cause deterioration of magnetic properties.

If the surface oxidation of the ferromagnetic particles does not exceed 5% by weight, there is no significant effect on the magnetic properties, but in order to achieve a high residual magnetic flux density, it is necessary that the content is preferably 3% by weight or less.

As additional components, R alone, R-Fe, RM, R-
Fe-M, an inorganic compound of R, an inorganic compound of Fe, and a mixed system of these and M can also be added. Also replace the above Fe
Addition systems replaced with Co or Fe-Co are also possible.

In particular, R-Fe alloys having a high affinity for ferromagnetic phases, such as R-Fe alloys having an R composition of 100 to 30 mol% or R-Zn of various compositions, and R-Fe-M such as R-Fe-Zn alloys. It is effective to add a multi-component system as an M component at each stage of the production process.

Manufacturing Method Next, a method for manufacturing the magnetic material of the present invention will be described, but the present invention is not particularly limited thereto.

FIG. 1 shows a flowchart of this manufacturing method. That is, (1) In the synthesis of the master alloy, a rare earth-iron alloy is synthesized, but at this stage, the M component can be added. In this case, although the magnetic flux density of the magnetic powder after nitriding pulverization tends to decrease, mainly the squareness ratio and the coercive force are improved. The magnetic material powder of the present invention can be produced by (2) 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 sublimation, which is particularly effective.

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. The composition of the R—Fe raw material alloy is preferably such that R is in the range of 5 to 25 mol% and Fe is in the range of 75 to 95 mol%. R in the R-Fe raw material alloy is 5 mol%
If it is less than the above, a large amount of α-Fe phase exists in the alloy, and a high coercive force cannot be obtained. Further, R in the R—Fe raw material alloy is 25 mol%.
If it exceeds, a high residual magnetic flux density cannot be obtained. The above description is about the composition of R in the R—Fe raw material alloy. The composition range of R in the R—Fe—N—H—M magnetic material must be 5 to 20 mol% as described above. 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 is easily precipitated when the alloy solidifies 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, an alloy having a desired composition can be produced by an alloy producing method such as a liquid quenching method and a roll rotation method by these methods. 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.

(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 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.

(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. is preferred. The penetration rate is low at low temperatures, 650
At a high temperature exceeding ℃, iron nitrides are formed and the magnetic properties are degraded. In the pressure treatment, the contents of nitrogen and hydrogen can be changed even with a pressure of about 10 atm.

A point to be noted in the nitridation and hydrogenation steps is oxidation. When a large amount of oxygen is present in the atmosphere, the magnetic characteristics are deteriorated. Therefore, it is desirable to lower the oxygen partial pressure as much as possible.

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.

(4) Finely pulverized In the R-Fe-NHM-based magnetic material, the most remarkable effect of the addition of M is that, after nitriding and hydrogenation, the M component is added and mixed at this stage and sintered. How to

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 most effective as a fine pulverizing method, but mixing and pulverizing with a method such as a cutter mill and a jet mill are also possible. However, the amount of hydrogen in the fine powder may change before and after pulverization by any of the pulverization methods, and it is necessary to control the amount of hydrogen within the range of the composition specified in the present invention. At this time,
The mixing and grinding conditions have a significant effect on 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 preferably about several μm to 10 μm, and when it reaches submicron, the reaction with the M component occurs too easily during sintering, and the magnetic properties after sintering are not so high. Does not improve. 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 reduced, 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.

(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 atmospheric sintering, hot pressing, and HIP.Here, a hot pressing method that improves magnetic properties and does not require a large device such as the HIP method, Atmospheric hot press is described.

Since the present magnetic powder is obtained by nitriding and hydrogenating a metal alloy, the desired magnetic properties cannot be obtained unless a predetermined amount of N and H is maintained in the structure after sintering. Therefore, 550
In the temperature range of from ℃ to 650 ℃, it is necessary to fire in a mixed gas containing ammonia gas, hydrogen gas or nitrogen gas. As described above, the NH ₃ —H ₂ mixed gas is particularly effective for controlling the amounts of N and H in the structure. However, 55
When sintering is performed in a temperature range of 0 ° C. or less, the amount of N and H in the structure is controlled by firing in a vacuum in an atmosphere of an inert gas such as argon or helium in addition to the above atmosphere gases. It is possible. At a temperature of 650 ° C. or higher, decomposition proceeds regardless of the atmosphere, an α-Fe phase precipitates, and the amounts of N and H change considerably from the initial amounts. Therefore, sintering at 650 ° C. or less is desirable, and the pressure of the hot press depends on the material of the die, but around 10 ton / cm ² is sufficient.

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)
_{The max} 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.

This was performed to confirm the formation of this two-phase separated microstructure.
FIG. 2 shows the results of EPMA (Electron Probe Micro-Analysis) observation. As a sample, Sm ₂ Fe ₁₇ N _4.0 H _0.5 M (M = Zn
(Molecule added 20 mol%), and M was used as an additive and added and mixed immediately before heat treatment. Heat treatment up to 440 ° C about 10
Heated at ° C / min and cooled immediately upon reaching. That is,
This is the earliest stage of sintering.

(A) is a normal SEM image, (b) is a component image, and the white portion is a phase having a Sm-rich composition such as Sm ₁ Fe ₃ , but most of the regions are uniform. Sm
_It can be identified as ₂ Fe ₁₇ composition. On the other hand, (c) and (d) are characteristic X-ray images of Fe and Zn, respectively, and white spots correspond to the presence of each element.

From the above results, it can be concluded from the consideration together with the magnetic characteristics that the low-melting element Zn as an additive quickly diffuses to the grain boundaries and forms a reaction phase by heat treatment.

That is, the effect of adding M according to the present invention and the form of the two-phase separation type microstructure due to the diffusion can be confirmed.

The sample of this photograph (FIG. 2) uses coarser grains than those of the other examples.

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 sufficient magnetization is preferably 15
It is kOe 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 rare earth-iron-nitrogen-hydrogen-M component material of the present invention is preferably 100 to 650 ° C. 100 ℃
Below, the effect of annealing is difficult to appear, and at 650 ° C. or higher, volatilization of nitrogen and hydrogen in the material is likely 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 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, hydrogen is occluded in the R-Fe-based raw material alloy, and then the obtained R-Fe-H alloy is finely pulverized. A method of performing a hydrogen intrusion treatment or a method of injecting nitrogen and hydrogen into the alloy after pulverizing by utilizing the fact that the alloy is pulverized by repeating hydrogen storage and desorption to the R-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.

Occlusion of hydrogen in the latter - Place a method of repeating the desorption example R-Fe-based alloy in an H ₂ atmosphere, the hydrogen storage by repeated raising and lowering of the temperature - can be repeated desorption.

Although it is not clear why fine powder having good crystallinity can be obtained by the above method, one of the reasons is that hydrogen penetrates between crystal lattices, so that energy required for pulverization can be reduced, and as a result, It is considered that the damage to the crystal is reduced. Also, in the case of pulverization by repeated hydrogen absorption and desorption, the crystal is not likely to be 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%, and then the molten metal was poured into a mold, cooled, and further cooled in an argon atmosphere.
By annealing at 1250 ° C. for 3 hours, the mole percentage becomes Sm10.5
% And an alloy having a crystal structure of Sm ₂ Fe ₁₇ composition of 89.5% Fe.

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 flowed into the tubular furnace, and nitrogen and hydrogen enter the alloy powder for 30 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 _72.4 N _17.0 H _2.1 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 _65.9 N _15.5 H _0.8 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 9.2 kG, coercive force (iHc) is 6.8 kOe, (BH) _max is 15.3 MGOe, squareness ratio (Br / 4
πIs) was 0.914.

Example 2 In the same procedure as in Example 1, a Sm ₂ Fe ₁₇ mother alloy was prepared.
This is nitrided and hydrogenated in an NH ₃ -H ₂ mixed gas to form Sm ₂ Fe ₁₇ N _x
A hydrogen nitride having a composition of H _y (x and y are shown in FIG. 3) was prepared, and 10 mol% of Zn was added thereto and subjected to a vibration ball mill to obtain a powder.

This powder is 1ton / cm ² , 15kOe using a uniaxial magnetic field press.
The magnetic field was formed into a plate of about 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 NH ₃ : H ₂ = 20: 80. However, a pressure of 10 ton / cm ² of the sintered magnet was continuously applied.

As a result, as shown in FIG. 3, it became clear that the amounts of nitrogen and hydrogen showed a strong correlation with the magnetic properties. (BH) _max
The region with the highest value is the Sm ₂ Fe ₁₇ N _x H _y M _z composition, x is about 4.0, y
Is about 0.5. In the experiment shown in this figure, z is x,
It changes with y.

X = 3.0-5.0, y = 0.01- even if the amount of nitrogen and hydrogen fluctuates
In the range of 1.0, relatively high magnetic properties can be obtained. This is correlated with the fact that the crystallinity of the raw material powder and the sintered body and the uniformity of the composition other than the composition affect the (BH) _max value.

Examples 3 to 6 10 mol% of Zn was added to and mixed with Sm ₂ Fe ₁₇ N _4.0 H _0.5 magnetic powder, and the mixture was pulverized with a vibration ball mill for about 1 hour.

This powder was formed into a plate of 10 × 5 × 2 mm under the conditions of 1 ton / cm ² and 15 kOe by a uniaxial magnetic field press. 650 ℃, 10ton /
Hot pressing was performed in an atmosphere gas of NH ₃ (20) -H ₂ (80) at cm ² .

Table 1 shows the magnetic properties of the powder before sintering and the magnetic properties of the sintered magnet when the sintering time was 1, 2, or 4 hours.

As described above, sintered magnets having various magnetic properties can be obtained by the hot pressing condition even with the magnetic powder having the composition of Sm ₂ Fe ₁₇ N _4.0 H _0.5 Zn _2.2 .

Examples 7 to 8 Including a low-melting element clearly improves the characteristic value, but it is also important to clarify the mechanism of the improvement. In particular, as the microstructure of the sintered magnet of the present invention, it is necessary to confirm the characteristics of the nonmagnetic phase at the grain boundary.

As M in the magnetic powder of Sm ₂ Fe ₁₇ N _4.5 H _0.5 M, Zn is 30
And 40 mol%, and mixed with a ball mill for 30 minutes, 1 ton
Magnetic field press molding was performed at 15 kOe / cm ² . These at 465 ° C, NH
And calcined 1 hour in an atmosphere of _{3 (35) -H 2 (65} ).

 The results are as shown in Table 2 below.

This result indicates that when a large amount of a nonmagnetic phase such as Zn is present between the particles, the coercive force is greatly increased. That is, the coercive force, which was 5 kOe when Zn was added at 30 mol%, reached 8 kOe at 40 mol%. On the other hand, the saturation magnetization decreases and is approximately a value obtained by multiplying the volume fraction of the magnetic powder by a certain constant.

Comparative Example 1 By arc-melting in a water-cooled copper boat under an argon atmosphere using Ce with a purity of 99.9% and Fe with a purity of 99.9%
An alloy having a composition of Ce 11.3 mol% and Fe 88.7 mol% was prepared. The obtained alloy was annealed at 950 ° C. for 72 hours under an argon atmosphere. Next, after pulverizing with a jaw crusher under a nitrogen atmosphere, the average particle size is further 30 μm with a coffee mill.
m.

The obtained alloy powder is placed in a tubular furnace, and at 420 ° C., a mixed gas flow of ammonia gas 0.4 atm and hydrogen gas 0.6 atm is flowed into the tubular furnace, and nitrogen and hydrogen enter the alloy powder for 1 hour. I was sorry.

Subsequently, Ce is gradually cooled to room temperature in the above atmosphere.
An alloy powder having a composition of _9.0 Fe _70.6 N _20.2 H _0.2 was obtained. This was sealed in an autoclave equipped with a pressure valve and a pressure gauge, and then the inside was evacuated, and then a mixed gas of hydrogen and ammonia was introduced to adjust the internal pressure to 4.4 atm.

At this time, the partial pressure of the ammonia gas is 1.8 atm. Next, the autoclave was heated by a heating furnace, and the alloy was treated at 465 ° C. for 30 minutes. Then gradually cooled to room temperature in the atmosphere to obtain an alloy powder of Ce _9.3 Fe _73.0 N _14.9 H _2.8 composition.

20 mol% of Zn was added to this alloy powder, and a vibrating ball mill was applied for 8 hours to obtain a fine powder having an average particle diameter of 1 μm.

The powder in the same manner as in Example 1 and the magnetic field shaping, then subjected to sintering to obtain a sintered magnet of _{Ce 7.5 Fe 59.0 N 12.0 H 1.5} Zn 20.0 composition magnetized.

The residual magnetic flux density (Br) of this sintered magnet was 3.0 kG, the coercive force (iHc) was 0.9 kOe, and (BH) _max was 0.5 MGOe.

Comparative Example 2 A copper roll having a diameter of 25 cm and a width of 2 cm was rotated, and a molten metal was sprayed on the roll to use a device for ultra-quick solidification of a liquid to obtain 10.7 mol% of Nd, 3.5 mol% of Pr, and Fe85 mol%. A raw material alloy having a composition containing 0.7 mol% and trace amounts of Ce, La, and Sm was produced. Before quenching, dissolve Nd50.7mol%, Pr
Didymium having a composition of 16.6 mol%, Ce0.17 mol%, La0.06 mol%, Sm0.02 mol%, Fe32.45 mol% and purity 99.9% F
e was filled and subjected to a high frequency melting method in an argon atmosphere.
The injection gas pressure was 1 kg / cm ² , the interval between the roll nozzles was 1 mm, and the rotation speed of the roll was 3000 rpm. The obtained dymium-
After crushing the iron flake sample to about 30 μm, it was subjected to nitrogen hydride in the same manner as in Example 1, and Nd _7.8 Pr _2.6 Fe _62.2 N _22.3 H _5.1
An alloy powder having the composition was obtained.

15 mol% of Zn was added to this alloy powder and subjected to a vibration ball mill for 3 hours to obtain a fine powder having an average particle size of 2 μm.

This was oriented in a magnetic field in the same manner as in Example 1, then sintered, magnetized, and Nd _6.6 Pr _2.2 Fe _53.1 N _19.0 H _4.1 Zn _15.0
A sintered magnet having the composition was obtained.

The residual magnetic flux density (Br) of this sintered magnet was 3.6 kG, the coercive force (iHc) was 1.2 kOe, and (BH) _max was 0.8 MGOe.

Example 9 99.9% pure Sm, 99.99% pure Co, and 99.9% pure
% Alloy containing 10.5% of Sm, 9.0% of Co and 80.5% of Fe by arc melting in a water-cooled copper boat under an argon atmosphere. The obtained alloy was annealed at 900 ° C. for 24 hours in an argon atmosphere. The resulting alloy was coarsely pulverized with a jaw crusher in a nitrogen atmosphere, and then further averaged with a coffee mill to an average particle size of 10.
Milled to 0 μm.

The resulting powder is passed through a mixed gas stream with a partial pressure of ammonia gas of 0.67 atm and a partial pressure of hydrogen gas of 0.33 atm in a tube furnace to absorb nitrogen and hydrogen at a reaction temperature of 470 ° C and a reaction time of 60 minutes. I let it. Subsequently, by slowly cooling to room temperature in the above atmosphere, Sm _8.3 Fe _63.3 Co _7.1 N _17.9 H _3.4
A powder having the following composition was obtained.

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 _58.3 Co _6.5 N _16.5 H _1.1 Zn
_{A 10.0} composition sintered magnet was obtained.

The residual magnetic flux density (Br) of this sintered magnet is 9.7 kG, coercive force (iHc) is 5.8 kOe, (BH) _max is 13.2 MGOe, squareness ratio (Br / 4
πIs) was 0.908.

Examples 10 to 19 and Comparative Example 3 To the Sm _8.5 Fe _72.4 N _17.0 H _2.1 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 3 was added and mixed. And about 1 hour in a vibrating ball mill. 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 3.

Examples 20 to 37 and Comparative Example 4 The Sm _8.5 Fe _72.4 N _17.0 H _2.1 magnetic powder obtained in Example 1 was mixed with the high melting point additive Mh or the inorganic compound Mi shown in Table 4
The mixture was added and mixed in the amounts shown in the table, and pulverized by a vibration ball mill for about 1 hour. This fine powder was magnetically molded in the same manner as in Examples 10 to 19, 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
s) is shown in Table 4.

The residual magnetic flux density [Br (kG)], coercive force [iHc (kOe)], (BH) _max (MGOe), squareness ratio (Br / 4πI) of these magnets
s) is shown in Table 4.

Examples 38 to 63 and Comparative Example 5 Additives Mh and Ml, Mi and Ml shown in Table 5 were added to the Sm _8.5 Fe _72.4 N _17.0 H _2.1 magnetic powder obtained in Example 1 in the amounts shown in Table 5 and mixed. Then, the mixture was pulverized with a vibration ball mill for about 1 hour.
This fine powder was magnetically molded in the same manner as in Examples 10 to 19, sintered, and magnetized to obtain a sintered magnet. These residual magnetic flux densities [Br (kG)], coercive forces [iHc (kOe)], (BH) _max
Table 5 shows (MGOe) and the squareness ratio (Br / 4πIs).

Examples 64-71 and Comparative Example 6 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%, and then the molten metal was poured into a mold, cooled, and further cooled in an argon atmosphere.
By annealing at 1100 ° C for 6 hours, the mole percentage becomes Sm1
An alloy consisting of 0.5% and 89.5% Fe was prepared.

This alloy was pulverized with a jaw crusher in a nitrogen atmosphere, and then coarsely pulverized by a coffee mill to an average particle size of 50 μm.

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 flowed into the tubular furnace, and nitrogen and hydrogen enter the alloy powder for 2 hours. At 450 ° C in a stream of argon
Annealed for 2.5 hours.

Subsequently, Sm was gradually cooled to room temperature in the above atmosphere.
An alloy powder having a composition of _8.9 Fe _75.4 N _15.5 H _0.2 was obtained.

Additive M shown in Table 6 was added to this alloy powder in an amount shown in Table 6, and the mixture was finely pulverized with a planetary ball mill for 25 minutes. This powder is 1ton / cm ² , 15kO using a uniaxial magnetic field press.
A magnetic field was formed into a plate of 5 × 10 × 2 mm under the conditions of e, and this was sintered at 200 ° C. for 30 minutes in a nitrogen gas stream. However, when sintering 1
The pressure of ² ton / cm ² was continuously applied. Next, the residual magnetic flux density [Br (k) of the sintered magnet obtained by magnetizing in the same manner as in Example 1 was obtained.
G)], coercive force [iHc (kOe)], (BH) _max (MGOe), and squareness ratio (Br / 4πIs) are shown in Table 6.

Example 72 Sm, Fe, and Zn having a purity of 99.9% were melted and mixed in a high-frequency melting furnace in an argon atmosphere, and then the molten metal was poured into a mold and cooled.
By annealing for a time, the mole percentage becomes Sm10.6%, Fe7
An alloy consisting of 7.8% and Zn 11.6% 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.
It was pulverized to a _{micron size} to obtain a fine powder of Sm _8.7 Fe _63.8 Zn _9.5 N _15.3 H _2.7 .

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 90 minutes.

The obtained sintered magnet had a residual magnetic flux density (Br) of 8.4 kG, a coercive force (iHc) of 4.2 kOe, a (BH) _max of 10.3 MGOe, and a squareness ratio (Br / 4πIs) of 0.880.

Example 73 and Comparative Example 7 The alloy powder having the composition of Sm _8.5 Fe _72.4 N _17.0 H _2.1 obtained in Example 1 was placed in a tubular furnace, and was placed in a hydrogen gas stream at 450 ° C. for 30 minutes.
Next, annealing was performed at 150 ° C. for 12 hours in a stream of argon gas. Then, by cooling to room temperature in the above atmosphere, Sm _8.7 F
e An alloy powder having a composition of _73.6 N _17.3 H _0.4 was obtained.

8 mol% of Zn was added to this alloy powder, and a vibrating ball mill was applied for 30 minutes to obtain a fine powder. Next, the fine powder was placed in a tubular furnace, annealed in a hydrogen gas stream at 350 ° C. for 2.5 hours, and gradually cooled to obtain fine powder A having a composition of Sm _8.0 Fe _67.7 N _15.9 H _0.4 Zn _8.0 .

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. .

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 7.

Table 7 also shows the magnetic properties of a bonded magnet obtained by subjecting a fine powder B obtained by pulverizing in the same manner as the fine powder A described above to a bonded magnet without adding Zn. .

Example 74 and Comparative Example 8 Melting and mixing were performed using a high-frequency furnace in an argon atmosphere using Sm having a purity of 99.9% and Fe having a purity of 99.9%, and then the molten metal was poured into a mold having a width of 3 mm, cooled, and further cooled in an argon atmosphere. By annealing at 950 ° C. for 32 hours, an alloy having a molar percentage of Sm10.5% and Fe89.5% was prepared.

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, nitrided and hydrogenated in the same manner as in Examples 64 to 71, and then annealed in an argon gas stream and gradually cooled to obtain Sm _8.9 Fe _75.4 N _15.5 H
An alloy powder having a _0.2 composition was obtained.

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 was placed in a tubular furnace, annealed in an argon gas stream at 430 ° C. for 1.5 hours, and gradually cooled to obtain fine powder C having a composition of Sm _8.2 Fe _69.5 N _14.3 H _0.05 Zn _8.0 .

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 8.

Table 8 also shows the magnetic properties of a bonded magnet obtained by subjecting a fine powder D obtained by pulverization in the same manner as the fine powder C described above to a bonded magnet without adding Zn. .

Example 75 The fine powder C obtained in Example 74 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 a weight ratio of 8: 2.
In a mold placed in a kOe magnetic field, the solvent was recovered,
Pellets were made.

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 8.0 kOe, (BH) _max was 15.6 MGOe, and squareness ratio (Br / 4πIs) was 0.950.

Example 76 Fine powder C and 6-nylon obtained in Example 74 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 6.5 kOe, (BH) _max was 5.5 MGOe, and squareness ratio (Br / 4πIs) was 0.798.

Examples 77 to 100 and Comparative Example 8 Sm and Fe having a purity of 99.9% and M shown in Tables 9 and 10
Dissolve and mix in a high frequency furnace in an argon atmosphere using the components,
Subsequently, the molten metal was poured into a mold, cooled, and further annealed at 1100 ° C. for 24 hours in an argon atmosphere, whereby, in terms of mole percentage, almost Sm 10.6%, Fe 84.9%, M component 4.5
% Of a mother alloy was prepared.

These Sm-Fe-M base alloys were subjected to nitrogenation / hydrogenation and pulverization treatment in the same manner as in Example 72 to obtain fine powder having a particle size of 4 µm. This powder was molded in the same manner as in Example 74. Tables 9 and 10 show the magnetic properties of the bonded magnet.

In addition, Table 10 also shows the results of forming a compact similar to the above using an Sm-Fe alloy prepared by adding the same mole number of Fe instead of the M component.

Comparative Example 9 An Sm-Fe-NHM-based sintered magnet was obtained in the same manner as in Example 72 except that the nitriding temperature was changed to 700 ° C.

 The intrinsic coercivity of this magnet was 0.05 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 10 Sm-Fe-N having an average particle size of about 7 μm obtained in Example 1
The -HM 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 specific coercive force of the compact is 0.
02kOe.

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.

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

[Brief description of the drawings]

FIG. 1 is a process diagram illustrating one method for producing the sintered magnet of the present invention, FIGS. 2 (a) to 2 (d) are micrographs of the crystal structure of the sintered magnet of the present invention, FIG. 3 is a graph showing a correlation between N and H contents and (BH) _max value.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Akinobu Sudo 2-1, Samejima, Fuji City, Shizuoka Prefecture Asahi Kasei Kogyo Co., Ltd.

Claims (9)

(57) [Claims] 1. A compound of the general formula R _α Fe _{(100-α-β-γ-δ)} N
is a magnetic material represented by _β H _γ · M _δ , R is a rare earth element mainly composed of samarium, M is Li, Na, K, Mg, Ca, Sr, Ba, Ti, Zr, Hf, V, N
b, Ta, Cr, Mo, W, Mn, Pd, Cu, Ag, Zn, B, Al, G
a, In, C, Si, Ge, Sn, Pb, Bi and these elements and R oxides, fluorides, carbides, nitrides, hydrides, carbonates, sulfates, silicates, chlorides , At least one of nitrates, α, β, γ, and δ are each represented by a molar percentage of 5 ≦ α ≦ 205 ≦ β ≦ 30 0.01 ≦ γ ≦ 10 0.1 ≦ δ ≦ 40, and at least R, Fe and A magnetic material, wherein the phase containing N substantially has a 2-17 structure. 2. 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 claim 1 is substituted with Co. 3. A phase comprising the magnetic material according to claim 1 or 2 and having a high content of M among the components represented by the general formula at a grain boundary of the microstructure of the structure. Have
A two-phase-separated bulk magnet, characterized in that the content of M is low or the phase does not contain M in the center of the particle. 4. A bonded magnet comprising the magnetic material according to claim 1 or 2. 5. A bonded magnet comprising the bulk magnet according to the above (3). 6. A magnetic material comprising R, Fe, N, H, or
To a material in which 0.01 to 50 mol% of Fe is replaced by Co, add the M component and pulverize, or pulverize and then add the M component,
The method for producing a two-phase-separated bulk magnet according to claim (3), wherein the M component is diffused and reacted mainly at the grain boundaries by sintering it. 7. The method for producing a magnetic material according to claim 1, wherein the M component is mixed and added during the synthesis of the master alloy. 8. The method for manufacturing a bulk magnet according to claim 3, wherein the M component is mixed and added during the synthesis of the master alloy. 9. The method for producing a bonded magnet according to claim 4, wherein the M component is mixed and added during the synthesis of the master alloy.