JPH0696918A - Nitride magnetic material - Google Patents

Abstract

PURPOSE:To obtain a magnetic material having a high magnetic characteristic and excellent oxidation resistance by mixing a specific metallic element in a rare-earth-iron-nitrogen material having a rhombohedral or hexagonal crystal structure. CONSTITUTION:This material is a magnetic material expressed by Ralpha(Fe(1-gamma) Mgamma)(100-alpha-beta)Nbeta (where, R and M respectively represent at least one kind selected from among rare-earth elements including Y and at least one kind selected from among Mn, Cr, and Ni and alpha, beta, and gamma respectively represent 3-20at.%, 3-3at.%, and 0.001-0.5at.%) and the phase containing M and N has a rhombohedral or hexagonal crystal structure. In the composition, in addition, the 0.01-50% of Fe content in the raw material of the magnetic material is replaced with Co. The alloy is heat-treated at 200-650 deg.C in an atmosphere containing at least one kind selected from a nitrogen gas and ammonia gas. Therefore, a magnetic material having an excellent oxidation resistance and high magnetic characteristic can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rare earth-iron-nitrogen based magnetic material having high magnetic properties and excellent oxidation resistance, and more particularly to a magnetic material most suitable for applications such as small motors and actuators.

[0002]

2. Description of the Related Art Magnetic materials are used in a wide range of fields such as home electric appliances, audio products, automobile parts and peripheral terminals of computers, and their importance as electronic materials is increasing year by year. In particular, recently, there has been a demand for miniaturization and high efficiency of various electric / electronic devices, so that a magnetic material with higher performance is required.

In response to the demands of this era, Sm-Co type, N
The demand for rare earth magnetic materials such as d-Fe-B system is rapidly increasing. However, the Sm-Co type has a problem that the supply of the raw material is unstable and the raw material cost is high, and the Nd-Fe-B type has poor heat resistance and corrosion resistance. On the other hand, as a new rare earth magnetic material, a rare earth-iron-nitrogen magnetic material has been invented. (For example, JP-A-2-57663) This material has high magnetization, anisotropic magnetic field, and high Curie point.
It is expected as a magnetic material that supplements the drawbacks of the d-Fe-B system. However, this magnetic material has the drawback of poor oxidation resistance. For a material having this rare earth-iron-M-nitrogen composition, see JP-A-60-14490.
6, JP-A-60-144907, JP-A-60-1449
09.

However, JP-A-60-144906-14
The material disclosed in 4909 becomes a material containing a large amount of iron nitride, α-iron, a rare earth nitride and a nitride of M from the manufacturing process and conditions thereof, and the magnetic properties such as coercive force are significantly deteriorated, These materials do not become high performance magnet materials. From this, a rare earth-iron-M-nitrogen-based material having a rhombohedral or hexahedral crystal structure with high magnetic properties and excellent in oxidation resistance is not currently known, and its appearance Strongly desired.

[0005]

DISCLOSURE OF THE INVENTION According to the present invention, a rare earth-iron-nitrogen-based material having a rhombohedral or hexagonal crystal structure is allowed to coexist with a metal element M to obtain high magnetic properties and excellent oxidation resistance. The present invention provides a magnetic material having a rare earth-iron-M-nitrogen composition and a method for producing the same.

[0006]

[Means for Solving the Problems] In order to obtain a rare earth-iron-nitrogen based magnetic material having high magnetic properties and oxidation resistance, as a result of extensive studies on a system in which various elements (M) are added to a mother alloy, The present invention has been accomplished by finding a rare earth (R) -iron (Fe) -M-nitrogen (N) based magnetic material having a composition and a crystal structure with high magnetic properties and excellent oxidation resistance.

That is, the present invention provides (1) the general formula Rα (Fe
_{(1- γ) Mγ) (100-} α - β) is a magnetic material represented by N.beta, at least one kind of rare earth element R, including the Y, M
Is at least one of the elements Mn, Cr, Ni,
α and β are atomic percentages 3 ≦ α ≦ 20 3 ≦ β ≦ 30 γ is an atomic ratio 0.001 ≦ γ ≦ 0.5, and the phase containing R, Fe, M and N is a diamond. A magnetic material containing a crystal structure of a tetrahedron and a hexagonal crystal, and (2) 0.01 to 50 atomic% of Fe, which is a component of the magnetic material according to claim 1, is replaced with Co. A magnetic material characterized by having the following composition:
(3) General formula Rα _{/ (100-} β ₎ (Fe _(1- γ ₎ Mγ) _(100- α
_{- beta) / (an} alloy represented by _{100- beta),} nitrogen gas, in an atmosphere containing at least one of ammonia gas, 200
The method for producing a magnetic material according to claim 1 or 2, wherein the heat treatment is performed in the range of 650 ° C.

The present invention will be described in detail below. As rare earth (R), Y, La, Ce, Pr, Nd, P
m, Sm, Eu, Gd, Tb, Dy, Ho, Er, T
It suffices to include at least one of m, Yb and Lu. Therefore, a mixture of two or more kinds of rare earth elements such as misch metal and didymium may be used, but preferable rare earth elements are Y, Ce, Pr, Nd, Sm, Gd, Dy, E
r. More preferably, Y, Ce, Pr, Nd,
It is Sm.

Further, this R may have a purity which can be obtained by industrial production, and impurities which are unavoidable in production, such as O, H,
C, Al, Si, F, Na, Mg, Ca, Li and the like may be present. Iron (Fe) is a basic composition of the present magnetic material that is responsible for ferromagnetism, and may be replaced with Co up to 50 atomic% at the maximum. Regarding the element M of Mn, Cr, and Ni, which is the point of the present invention, the Mn, Cr, and
The element (M) of Ni is made to coexist at 0.001 to 50 atomic% with respect to Fe.

The composition of the R-Fe-MN magnetic material in the present invention is in the range of 3 to 20 atomic% of rare earth, 50 to 94 atomic% of iron and M components together, and 3 to 30 atomic% of N. Need to be in. When the R component is less than 3 atom%,
The soft magnetic phase containing a large amount of iron component separates, and the coercive force of the nitride decreases, so that a practical permanent magnet cannot be obtained. Also, the R component is 2
If it exceeds 0 atom%, the residual magnetic flux density is lowered, which is not preferable. The composition of the rare earth is preferably 5 to 15 atom%, more preferably 7 to 12 atom%.

The M component coexisting with iron must be in the range of 0.001 to 0.5 in atomic ratio with respect to the total of the iron and M components. If it exceeds 0.5, the saturation magnetization is lowered, which is not preferable, and if it is less than 0.001, there is almost no effect of adding M on the oxidation resistance. The coexisting amount of M is preferably 0.01 to 0.2. Further, iron is 0.0 in Co.
When 1 to 50 atom% is substituted, the Curie point and the magnetization are high,
Further, the material has high oxidation resistance.

In addition to Mn, Cr and Ni as M components, Li, Na, K, Mg, Ca, Sr, Ba and Ti,
Zr, Hf, V, Nb, Ta, Mo, W, Pd, Cu,
Ag, Zn, B, Al, Ga, In, C, Si, Ge,
One or more elements (M ′ component) of Sn, Pb and Bi elements may be added, but the content of these elements is M.
Do not exceed the total amount of n, Cr, Ni, and Mn, C
The total amount of r and Ni must be within the range of γ value.

The crystal structure of the main phase of the R-Fe-MN magnetic material must include at least one of hexagonal and rhombohedral crystals in a volume fraction of 50% or more. For example, a highly magnetic nitride phase having a tetragonal structure such as RFe _12-x M _x N _y phase may be contained, but in order to fully exert the effect of the oxidation resistance of the present invention, its volume fraction is The volume fraction of the magnetic material of the present invention should not be exceeded. When the volume fraction exceeds 75% by volume, it is a very preferable material for practical use. The main phase of the R-Fe-M-N-based material obtained in the present invention has a crystal structure having substantially the same symmetry as the main phase of the R-Fe-M alloy used as the raw material, and nitrogen penetrates into the interstitial spaces. Or is introduced by substituting the M component or the like, and the crystal lattice is expanded in many cases.

Along with this, one or more of the items of oxidation resistance and magnetic properties are improved, and the magnetic material is suitable for practical use. The magnetic property here means the saturation magnetization of the material (4π
Is), residual magnetic flux density (Br), magnetic anisotropic magnetic field (H
a), magnetic anisotropy energy (Ea), magnetic anisotropy ratio,
Curie point (Tc), intrinsic coercive force (iHc), squareness ratio (Br / 4πIs), maximum energy product [(BH) ma
x], and at least one of the thermal demagnetization rates. However, the magnetic anisotropy ratio is the ratio (a / b) of the magnetization (a) in the difficult magnetization direction and the magnetization (b) in the easy magnetization direction when an external magnetic field of 15 kOe is applied. The smaller the value, the higher the magnetic anisotropy energy.

[0015] For example, rare earth - as an iron -M master alloy, when choosing the _{Sm 10.5 (Fe 0. 9 Ni 0.1} ) 89.5 having a rhombohedral structure, by introducing nitrogen, crystal magnetic anisotropy in-plane Anisotropy changes to uniaxial anisotropy suitable for a hard magnetic material, and magnetic properties such as magnetic anisotropy energy and oxidation resistance are improved. The amount of nitrogen (N) introduced is 3
Must be ~ 30 atomic%. If it exceeds 30 atomic%, the magnetization is low, and its practicality as a magnet material is small. If it is less than 3 atomic%, the performance of the raw material alloy cannot be improved so much, which is not preferable. The amount of nitrogen is more preferably 5 to 25 atomic%, particularly preferably 10 to 17
It is atomic%.

Also, depending on the R-Fe-M composition ratio of the target R-Fe-M-N magnetic material and the amount ratio of the sub-phase,
The optimum amount of nitrogen is different, for example, Nd having a rhombohedral structure.
_{When 10.5} (Fe _0.9 Mn _0.1 ) _89.5 is selected as the raw material alloy,
The optimum nitrogen amount is around 13 to 14 atom%. The optimum nitrogen amount at this time is the nitrogen amount for which at least one item of the oxidation resistance and magnetic properties of the material is optimal although it varies depending on the purpose, and the optimal magnetic property is the magnetic anisotropy ratio, The demagnetization rate is minimum, and the others are maximum.

The R—Fe—M—N magnetic material obtained by the present invention contains 0.01 to 15 atomic% of hydrogen (H) and 0.01 to 15 atomic% of oxygen (O). It is preferable. A more preferable amount of hydrogen and oxygen is 0.1 to
It is 10 atomic% and 0.1-10 atomic%. Therefore, the particularly preferable composition of the R-Fe-M-N-based material of the present invention is
General formula Rα (Fe _(1- γ ₎ Mγ) _(100- α _- β _- δ _- ε ₎ Nβ
When expressed by HδOε, α, β, δ, ε are atomic%, 2.4 ≦ α ≦ 20 2.4 ≦ β ≦ 30 0.1 ≦ δ ≦ 10 0.1 ≦ ε ≦ 10 γ is an atomic ratio Then, the range is 0.001 ≦ γ ≦ 0.5.

The coexistence effect of the M component with respect to the R—Fe—N magnetic material is mainly improvement of oxidation resistance. In particular,
Deterioration of the R—Fe—N-based magnetic material due to oxidation causes a problem of a decrease in coercive force as compared with a decrease in magnetization. The composition of the present invention is characterized by excellent stability of coercive force against oxidation. The source of the effect is due to the coexistence of the M component in the main phase of the R-Fe-N magnetic material that is responsible for ferromagnetism. However, the main phase itself is not easily oxidized and prevents deterioration of the magnetization. The M component is contained in the soft magnetic component mainly composed of iron, and the precipitation state is affected, which also contributes to preventing the decrease in the coercive force of the nitride magnetic material.

Depending on the preparation method and conditions of the master alloy, R-rich nitride phases such as near the grain boundaries or in the RFe ₃ phase, and R-Fe such as α-Fe phase or its nitride phase may be used.
In the material of -N composition, a large amount of M component is distributed to the sub-phase exhibiting soft magnetism to form a non-magnetic phase, thereby improving the squareness ratio and coercive force of the nitride, and improving the oxidation resistance. There is also an effect to do.

The production method of the present invention will be illustrated below. (1) Preparation of master alloy In the magnetic material of the present invention, R-Fe- serving as a nitriding raw material
The main phase of the M alloy has a structure in which the M component replaces the Fe site in the R-Fe alloy crystal structure, and / or the sub-phase has a composition and structure different from that of the R-Fe binary system due to the addition of M. The effect of the present invention is exhibited. Therefore, it is desirable to add M at the stage of adjusting the mother alloy.

The R-Fe-M alloy can be produced by using R,
High-frequency melting method in which Fe and M metals are melted by high frequency and cast in a mold, arc melting method in which metal components are charged in a boat such as copper and melted by arc discharge, high-frequency molten metal is rotated on a copper roll Quenching method for obtaining a ribbon-shaped alloy, a gas atomization method for obtaining an alloy powder by spraying a high-frequency molten metal with a gas, Fe and / or M powder or Fe-M alloy powder, R and / or M powder R / D method of reacting an oxide powder and a reducing agent at a high temperature to reduce R or R and M while diffusing R or R and M into Fe and / or Fe-M alloy powder. A mechanical alloying method in which a metal component alone and / or an alloy is reacted while being finely pulverized by a ball mill or the like, and the alloy obtained by any one of the above methods is heated in a hydrogen atmosphere, and once converted into a hydride of R and / or M. Decomposed into Fe and or M or Fe-M alloy, both the may be used in the HDDR method alloying are recombined while removing hydrogen as low at a high temperature after this.

When the high frequency melting method or the arc melting method is used, a soft magnetic component mainly composed of Fe is likely to precipitate from the molten state when the alloy is solidified, and particularly the coercive force is lowered even after the nitriding step. Therefore, for the purpose of eliminating the soft magnetic component or improving the crystallinity, the temperature is 800 ° C. or higher in an inert gas such as argon or helium or in a vacuum.
It is effective to anneal in the temperature range of 1300 ° C.
The alloy produced by this method has a large crystal grain size, good crystallinity, and high residual magnetic flux density, as compared with the case of using the ultra-quenching method.

When the ultraquenching method is used, fine crystal grains are obtained, and submicron particles can be prepared depending on the conditions. However, when the cooling rate is high, the alloy becomes amorphous and the magnetic properties such as magnetization are deteriorated even after nitriding. Also in this case, annealing after alloy preparation is effective.
The alloy obtained by the gas atomization method often takes a spherical form, and fine powder to coarse powder can be prepared. Also in this case, depending on the conditions, it is necessary to perform annealing to improve the crystallinity. R / D in addition to this method
The alloy prepared by the method, the mechanical alloying method, or the HDDR method can have fine crystal grains adjusted, the composition of the M component has a distribution, or a pinning type magnet material. It is possible to make the effect of the present invention more remarkable.

By the way, depending on the annealing conditions, the crystal phase of the alloy may differ. For example, depending on the R component,
Depending on whether it is annealed or quenched, it may have a rhombohedral system or a hexagonal system. Therefore, it is necessary to pay sufficient attention to the annealing conditions, and the target crystal phase can be selected by controlling the annealing conditions. (2) Coarse crushing and classification It is also possible to directly nitride the alloy ingot produced by the above method, but if the crystal grain size is larger than 500 μm, the nitriding time will be longer, and it is better to carry out coarse crushing before nitriding. It is efficient.

For coarse crushing, a jaw crusher, a hammer,
It is performed by using a stamp mill, a rotor mill, a pin mill, a coffee mill, or the like. Further, even if a crusher such as a ball mill or a jet mill is used, it is possible to prepare an alloy powder suitable for nitriding depending on the conditions. Also, after coarse crushing,
Adjusting the particle size using a sieve, a vibration type or a sonic type classifier, or a cyclone is also effective for performing more uniform nitriding.

After coarse pulverization and classification, annealing in an inert gas or hydrogen can remove structural defects, which is effective in some cases. In the above, the rare earth-iron alloy powder raw material or ingot raw material preparation method in the production method of the present invention has been illustrated.
The optimum conditions for nitriding shown below differ depending on the microstructure and surface condition. (3) Nitriding / annealing In nitriding, a gas containing at least one of ammonia gas and nitrogen gas is brought into contact with the R-Fe-M alloy powder or ingot obtained in the above (1) or (1) and (2). And the step of introducing nitrogen into the crystal structure.

At this time, coexistence of hydrogen gas in the nitriding atmosphere gas is preferable because the nitriding efficiency is high and the nitriding can be performed while the crystal structure is stable. In addition, in order to control the reaction, an inert gas such as argon, helium, or neon may coexist. The nitriding reaction can be controlled by gas composition, heating temperature, heat treatment time, and pressure. Among them, the heating temperature is selected in the range of 200 to 650 ° C., though it depends on the mother alloy composition and the nitriding atmosphere. If the temperature is 200 ° C. or lower, the penetration rate of nitrogen is slow and the reaction takes too long, which is not preferable, and if the temperature is 650 ° C. or higher, the main phase is decomposed and the magnetic properties are deteriorated.

After nitriding, it is preferable to anneal in an inert gas and / or hydrogen gas in order to improve the magnetic properties. Examples of the nitriding / annealing device include horizontal and vertical tubular furnaces, rotary reaction furnaces, and closed reaction furnaces. It is possible to adjust the magnetic material of the present invention in any of the apparatuses, but it is preferable to use a rotary reactor in order to obtain a powder having a uniform nitrogen composition distribution.

The gas used for the reaction is an air flow system in which a gas flow of 1 atm or more is sent to the reactor while keeping the gas composition constant, an encapsulation system in which the gas is sealed in a container at a pressure of 0.01 to 70 atm, or Supply them in combination. As a method for producing the present magnetic material, a step of preparing a master alloy having an R—Fe—M composition by the method exemplified in (1) and (2) and then nitriding it by the method shown in (3) is used. Is most preferable, and according to this method, the M component having a high melting point can be contained in a desired portion of the mother alloy, which is particularly effective in improving the oxidation resistance.

The above is a description of the method for producing the R—Fe—M—N magnetic material of the present invention. When the magnetic material of the present invention is applied as a practical hard magnetic material, the above steps are performed. Then, (4) fine pulverization, (5) magnetic field molding, and (6) magnetization may be performed. The example will be briefly described below. (4) Fine pulverization For example, among single-domain particle type R—Fe—M—N magnetic materials, when it is desired to maintain a large crystal grain size even after nitriding treatment and to develop a large coercive force, Fine pulverization is performed when it is desired to keep the polycrystalline particles even after the treatment and to obtain an anisotropic hard magnetic material.

As a method of fine pulverization, a rotary ball mill,
Vibratory ball mills, planetary ball mills, wet mills, jet mills, cutter mills, pin mills, automatic mortars and combinations thereof are used. The fine pulverization method is selected according to the adjustment of the amount of hydrogen or oxygen and the target pulverized particle size.

As a method for controlling the amounts of hydrogen and oxygen within the particularly preferred range of the present invention, for example, when a jet mill is used, the oxygen and water vapor concentrations in the pulverized gas are maintained at a predetermined concentration, and an attritor or the like is used. When wet pulverization is used, methods such as adjusting the amount of dissolved oxygen and water in the solvent can be mentioned. (5) Magnetic field molding For example, when the magnetic powder obtained in (3) or (4) is applied to an anisotropic bonded magnet, it is mixed with a thermosetting resin or a metal binder and then compression molded in a magnetic field. After kneading with a thermoplastic resin, injection molding in a magnetic field,
Magnetic field molding.

The magnetic field shaping is preferably 10 kOe in order to sufficiently orient the R-Fe-M-N magnetic material in the magnetic field.
Above, more preferably in a magnetic field of 15 kOe or more. (6) Magnetization The anisotropic bonded magnet material and the sintered magnet material obtained in (5) are usually magnetized in order to improve the magnet performance.

The magnetization is, for example, an electromagnet that generates a static magnetic field,
It is performed by a condenser magnetizer that generates a pulsed magnetic field. The magnetic field strength for sufficiently magnetizing is preferably 15 kOe or more, more preferably 30 kOe or more.

[0035]

EXAMPLES The present invention will be specifically described below with reference to examples. The evaluation method is as follows. (1) Magnetic characteristics An R-Fe-MN magnetic material having an average particle diameter of about 3 μm was used at an external magnetic field of 15 kOe and 12 ton / cm ² at 5 mm × 1.
After shaping into about 0 mm × 2 mm and pulse-magnetizing at room temperature with a magnetic field of 60 kOe, the intrinsic coercive force (iHc / kOe) was measured using a vibrating sample magnetometer (VSM). (2) Nitrogen content, oxygen content, and hydrogen content Si ₃ N ₄ (including a fixed amount of SiO ₂ ) was used as a standard sample, and the nitrogen content and oxygen content were quantified by the inert gas fusion method. The amount of hydrogen was quantified by an inert gas melting method using high-purity hydrogen gas (99.999%) as a standard gas. (3) Average particle size It was evaluated using a Lee-Nurse specific surface area meter. (4) Oxidation resistance performance A molded product of powder having an average particle diameter of 3 μm evaluated in (1) was
The sample was placed in a constant temperature bath at 10 ° C. and the intrinsic coercive force after 200 hours was measured in the same manner as in (1), and the retention rate (%) of the intrinsic coercive force was determined by comparing with the result of (1). The higher the retention rate, the higher the oxidation resistance performance. (5) Oxidation test 10 mg of a coarse powder sample adjusted to have an average particle size of 15 μm was placed in a thermobalance, and the heating rate was 1 in an air stream of 50 ml / min.
The rate of weight change (% by weight) from 50 ° C. to 250 ° C. was measured under the condition of 0 ° C./min. The smaller the weight change rate, the less likely it is to be oxidized.

[0036]

Example 1 Sm having a purity of 99.9%, Fe having a purity of 99.9%, and Ni having a purity of 99.9% were melt-mixed in a high-frequency melting furnace in an argon gas atmosphere, and then the molten metal was cast into a pure iron mold. It is poured into the inside of the container, cooled, and further annealed at 1050 ° C. for 35 hours in an argon atmosphere to obtain Sm.
An alloy having a composition of _11.0 (Fe _0.9 Ni _0.1 ) _89.0 was prepared.

This alloy was crushed with a jaw crusher and then further crushed with a rotor mill in a nitrogen atmosphere, and the particle size was adjusted with a sieve to obtain a powder having an average particle size of about 50 μm. This Sm-Fe-Ni alloy powder was charged into a horizontal tubular furnace and the ammonia partial pressure was 0.32 at 450 ° C.
After heat treatment in a mixed gas flow of atm and hydrogen gas of 0.68 atm, followed by annealing in an argon gas flow, the average particle size was adjusted to about 15 μm. Then, the powder was pulverized by a jet mill to an average particle size of about 3 μm. At this time, as the pulverizing gas, a gas containing nitrogen as a main component and partially mixing oxygen and water vapor was used.

Table 1 shows the composition, oxidation resistance and oxidation test results of the obtained Sm-Fe-Ni-N powder. The intrinsic coercive force of the Sm-Fe-Ni-N-based powder compact pulverized to about 3 μm was 5.1 kOe and the residual magnetic flux density was 8.7 k.
It was G. As a result of analysis by an X-ray diffraction method, the crystal structure of this material was mainly rhombohedral, and no diffraction line corresponding to Ni alone was observed.

[0039]

Examples 2 to 5 By following the same procedure as in Example 1 except that the composition of the mother alloy was changed to the composition ratio shown in Table 1, R-F was obtained.
An e-M-N powder was obtained. The results are shown in Table 1. From the results of X-ray diffraction, the materials of Examples 2, 3 and 5 were mostly substances having rhombohedral crystals, and the materials of Example 4 were tetragonal to substances having rhombohedral crystals. It was found that the substances that it had were mixed.

[0040]

[Comparative Example 1] Sm-F was prepared in the same manner as in Example 1 except that Ni was not added and Fe was added in an amount (atomic%).
An eN powder was obtained. The results are shown in Table 1.

[0041]

[Comparative Example 2] Nd-F was prepared in the same manner as in Example 2 except that Mn was not added and Fe was added in the amount (atomic%).
An eN powder was obtained. The results are shown in Table 1.

[0042]

Comparative Example 3 Sm having a particle size of about 3 μm obtained in Example 3
_9.2(Fe_0.9Cr_0.1)_74.8N_13.8H_0.5O _1.7Composition of powder
2 ton / cm², Magnetic field shaping under conditions of 15 kOe
Then, under argon atmosphere, the condition of 800 ℃, 1 hour
Heat treatment was performed. Peculiarity of the molded body when it is rapidly cooled
The coercive force was 0.06 kOe. About this molded body again
The intrinsic coercive force of powder pulverized to 3 μm is 0.07 kOe.
there were. The crystal structure of this material was analyzed by X-ray diffraction.
As a result, mainly diffraction lines corresponding to α-iron and iron nitride were detected.
Was done.

[0043]

[Table 1]

[0044]

As described above, according to the present invention, it is possible to provide a rare earth-iron-nitrogen based magnetic material having excellent oxidation resistance and high magnetic properties.

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[Procedure amendment]

[Submission date] October 8, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

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[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0005

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[0005]

DISCLOSURE OF THE INVENTION According to the present invention, a rare earth-iron-nitrogen-based material having a rhombohedral or hexagonal crystal structure is allowed to coexist with a metal element M, and high magnetic properties and excellent oxidation resistance are obtained. The present invention provides a magnetic material having a rare earth-iron-M-nitrogen composition and a method for producing the same.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

That is, the present invention provides (1) the general formula Rα (Fe
_{(1- γ) Mγ) (100-} α - β) is a magnetic material represented by N.beta, at least one of the at least one, M is, Mn, Cr, Ni element selected from rare earth elements R are including Y , Α and β are atomic percentages 3 ≦ α ≦ 20 3 ≦ β ≦ 30 γ are atomic ratios 0.001 ≦ γ ≦ 0.5, and the phase containing R, Fe, M and N is A magnetic material containing a rhombohedral or hexagonal crystal structure, and (2) 0.01 to 50 atomic% of Fe, which is a component of the magnetic material according to claim 1, is Co. A magnetic material characterized by having a substituted composition, (3) General formula Rα _{/ (100-} β ₎ (Fe _(1- γ ₎ Mγ)
_The alloy represented by _(100- α _- β _{) / (100-} β ₎ is heat-treated at a temperature of 200 to 650 ° C. in an atmosphere containing at least one of nitrogen gas and ammonia gas. The method for producing a magnetic material according to claim 1 or 2.

[Procedure amendment 4]

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Further, this R may have a purity which can be obtained by industrial production, and impurities which are unavoidable in production, such as O, H,
C, Al, Si, F, Na, Mg, Ca, Li and the like may be present. Iron (Fe) is a basic composition of the present magnetic material that is responsible for ferromagnetism, and may be replaced with Co up to 50 atomic% at the maximum. Regarding the element M of Mn, Cr, and Ni, which is the point of the present invention, the Mn, Cr, and
Fe + M of one or more of Ni elements (M)
On the other hand, 0.1 to 50 atomic% is made to coexist.

[Procedure Amendment 5]

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The crystal structure of the main phase of the R-Fe-MN magnetic material must contain at least one of hexagonal and rhombohedral crystals in a volume fraction of 50% or more. The main phase is a phase containing R, Fe, M and N and having a rhombohedral or hexagonal crystal structure, and a phase having other composition and crystal structure is called a subphase. For example, the subphase may include a highly magnetic nitride phase having a tetragonal structure such as RFe _12-x M _x N _y phase, but in order to fully exert the effect of the oxidation resistance of the present invention, The volume fraction should not exceed the volume fraction of the magnetic material of the present invention. When the volume fraction exceeds 75% by volume, it is a very preferable material for practical use. The main phase of the R-Fe-M-N-based material obtained in the present invention has a crystal structure having substantially the same symmetry as the main raw material phase of the R-Fe-M alloy used as the raw material, and nitrogen is present in the interstitial lattice. It is introduced or replaced with the M component, and the crystal lattice is expanded in many cases. The main raw material phases are R, Fe,
A phase that contains M and has a rhombohedral or hexagonal crystal structure, and has a composition and crystal structure other than that,
A phase that does not contain N is called an auxiliary material phase.

[Procedure correction 6]

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With the expansion of the crystal lattice, one or more of the items of oxidation resistance and magnetic properties are improved, and the magnetic material is suitable for practical use. The magnetic properties referred to here are the saturation magnetization (4πIs) of the material, the residual magnetic flux density (Br), the magnetic anisotropy magnetic field (Ha), the magnetic anisotropy energy (Ea), the magnetic anisotropy ratio, and the Curie point ( Tc), intrinsic coercive force (iHc),
Squareness ratio (Br / 4πIs), maximum energy product [(B
H) max], thermal demagnetization rate (α), and temperature change rate (β) of coercive force. However, the magnetic anisotropy ratio is the ratio (a / a) between the magnetization (a) in the difficult magnetization direction and the magnetization (b) in the easy magnetization direction when an external magnetic field of 15 kOe is applied.
b), and the smaller the magnetic anisotropy ratio, the higher the magnetic anisotropy energy is evaluated.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

Also, depending on the R-Fe-M composition ratio of the target R-Fe-M-N magnetic material and the amount ratio of the sub-phase,
The optimum amount of nitrogen is different, for example, Nd having a rhombohedral structure.
_{When 10.5} (Fe _0.9 Mn _0.1 ) _89.5 is selected as the raw material alloy, the optimum nitrogen content is around 13 to 14 atom%. The optimum nitrogen amount at this time is the nitrogen amount for which at least one item of the oxidation resistance and magnetic properties of the material is optimal although it varies depending on the purpose, and the optimal magnetic property is the magnetic anisotropy ratio,
The absolute value of the temperature change rate of the demagnetization rate and the coercive force is minimum, and the others are maximum.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

The production method of the present invention will be illustrated below. (1) Preparation of master alloy In the magnetic material of the present invention, R-Fe- serving as a nitriding raw material
The main raw material phase of the M alloy has a structure in which the M component replaces the Fe site in the R-Fe alloy crystal structure, and / or the auxiliary raw material phase has a composition different from the binary system of R-Fe by the addition of M,
It has a structure and exhibits the effects of the present invention. Therefore, it is desirable to add M at the stage of adjusting the mother alloy.

Claims (3)

[Claims] 1. The general formula R α (Fe _(1- γ ₎ M γ) _(100- α _- β
₎ A magnetic material represented by Nβ, R is at least one of rare earth elements including Y, M is at least one of Mn, Cr, and Ni elements, and α and β are atomic percentages of 3 ≦ α ≦ 20. 3 ≦ β ≦ 30 γ is an atomic ratio of 0.001 ≦ γ ≦ 0.5, and the phase containing R, Fe, M and N contains a rhombohedral and hexagonal crystal structure. Magnetic material characterized by. 2. A magnetic material having a composition in which 0.01 to 50 atomic% of Fe, which is a component of the magnetic material according to claim 1, is replaced by Co. 3. The general formula Rα _{/ (100-} β ₎ (Fe _(1- γ ₎ Mγ)
_The alloy represented by _(100- α _- β _{) / (100-} β ₎ is used in an atmosphere containing at least one of nitrogen gas and ammonia gas,
The method for producing a magnetic material according to claim 1 or 2, wherein the heat treatment is performed in the range of 200 to 650 ° C.