JPH06349612A - Magnetic material, its manufacture and its usage method - Google Patents

Abstract

PURPOSE: To obtain a magnetic material having superior magnetic characteristics by containing at least a rate-earth element, iron, a VA group element and one or more other specific elements. CONSTITUTION: This magnetic material is expressed by Rx Fey X'a Zb , consisting of a rhombohedral crystal system (Γrh ), a hexagonal system (Γh ) or a tetragonal system (Γt ), where R indicates one or more kinds of rare-earth elements, X' indicates III A, III B, IV A or IV B group element, Z indicates one or more kinds of rare-earth elements in the form of 0.5<=x<=2, 9<=y<=19, 0<=a<=e and 0.3<=b<=3. Also, when this magnetic material is composed of an intermetallic compound of (Γrh ) or (Γh ) crystal structure, Fe is not replaced by other element, or a part of Fe is replaced by other element. When the magnetic material is composed of the intermetallic compound of (Γt ) crystal structure, Fe is partially replaced by an arbitrary element of IV A group or a transitional metal of another group. Moreover, when the magnetic material is composed of the crystal structure of (Γrh ) or (Γt ), it is to be a condition that X' is not B when Z is Sb or Bi.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel magnetic material having improved magnetic properties, a method for producing the same and a method of using the novel material for making a permanent magnet.

[0002]

2. Description of the Related Art A magnet is a motor, a generator, a focusing element,
It has many uses in engineering and scientific fields as a component of various devices such as a lifting mechanism, a locking device, a levitation device, an anti-friction mount, and the like. Three unique properties are extremely important for magnetic materials to be useful in making permanent magnets. These characteristics are the Curie temperature (T _C ), that is, the temperature at which the permanent magnet loses its magnetism, the spontaneous magnetic moment (M _S ) per unit volume, and the easy direction conventionally represented by the anisotropic magnetic field Ba. It is uniaxially anisotropic. The Curie temperature is especially important because the device containing the magnet must be operated below the temperature specified by it.

Throughout this century, much research has been directed to the development of magnetic materials having both high Curie temperatures and improved magnetic moments and strong uniaxial anisotropy. Alnico (AlNiCo) type magnetic materials have been put to practical use for permanent magnets for many years, but in the late 1960s, rare earth alloys, especially samarium alloys alloyed with cobalt, made permanent magnets superior to AlNiCo types. It has been discovered that it has the magnetic properties it obtains. Magnets derived from compounds of samarium and cobalt have been especially successful in many applications requiring magnets with high energy products. However, since the cost of cobalt as a raw material is high, the possibility of combining cheaper and richer iron with magnetically superior rare earth elements in order to manufacture permanent magnets with improved magnetic properties in the early 1980s. Came to be considered. In 1983, Sumitomo Special Metals Co., Ltd. and General Motors of the United States independently developed an intermetallic compound, Nd ₂ Fe ₁₄ B, in which a rare earth element and iron were combined and boron was introduced as a third element into the crystal lattice of the element. It made a big leap forward. Although this intermetallic compound can be used to make magnets with excellent energy products, its Curie temperature is lower than Sm-Co materials. These Nd-Fe-B based magnetic materials are 320 ° C.
It may have the following Curie temperatures, but these are especially European patents EP-A-0101552, EP-A-01069.
48 and EP-A-0108474.
Derivatives of these boride materials represent the state of the art in today's magnet applied science.

[0004]

However, since these magnetic materials are somewhat unstable in air and chemically change to gradually lose their magnetic properties, the Curie temperature is 300 ° C.
However, it is actually unsuitable for use at temperatures above 150 ° C.

On the other hand, a new compound combining an element other than boron with a rare earth element and iron was inspired by the fact that the introduction of boron into the crystal lattice of an intermetallic compound material containing a rare earth element and iron improves the magnetic properties. The quest for was promoted.

In 1987, Higan et al.
We have reported an attempt to carry out a nitriding reaction by exposing powder of Sm ₂ Fe ₁₇ alloy to gaseous nitrogen at a temperature of 100 ° C. (IEEE Magnetics Society Bulletin Mag-23, No. 5, 1).
September 987). This experiment was intended to produce a compound of the formula: Sm ₂ Fe ₁₇ —N in the hope that the magnetic properties would be improved. However, Higano, etc.
No proof was found that such a material was produced by this method; instead, the nitriding method readily decomposes the rare earth-iron alloy starting material to produce rare earth element nitrides and iron. I just found something to do.

The present inventor has obtained a novel magnetic material having improved properties, which contains at least a rare earth element, iron, and a Group VA element and may optionally contain one or more other elements.
The successful manufacture of these materials is unexpected, even considering the teachings of Higano et al.

[0008]

Means for Solving the Problems As a means for solving the above problems, the present invention provides a general formula: R _x derived from an intermetallic compound having a rhombohedral, hexagonal or tetragonal crystal structure. The magnetic material represented by Fe _{y X'a} Z _b is provided. However, in the formula, R is one or more rare earth elements,
X'is an element of group IIIA, IIIB, IVA or IVB of the periodic table, Z is one or more elements of group VA of the periodic table, and x is 0.5 to 0.5.
Value of 2, y is a value of 9 to 19, a is a value of 0 to 3, b is 0.
When the magnetic material represented by the general formula is derived from an intermetallic compound having a rhombohedral or hexagonal crystal structure, Fe is not substituted by another element. Alternatively, when the magnetic material represented by the above general formula, which is partially substituted, is derived from an intermetallic compound having a tetragonal crystal structure, Fe is any element of Group IIIA or IVA of the periodic table, or other In the case of a magnetic material that is partially substituted with a transition metal of the group III, and is further derived from the rhombohedral or hexagonal crystal structure, when the component Z is antimony or bismuth, the element X ′ is not boron. As a condition.

In the present specification, the rare earth element includes the elements yttrium and thorium, which are IIIA and III in the periodic table.
Group B, IVA, IVB, V should be understood as defined in the CAS version of the Periodic Table. Also, the hexagonal system,
Rhombohedral and tetragonal crystal structures refer to Th ₂ N
means an intermetallic compound having a i _17, Th ₂ Zn ₁₇ and crystal structure similar respectively ThMn _12.

When the magnetic material is derived from an intermetallic compound having a hexagonal or rhombohedral crystal structure, the element R may be samarium alone or lanthanum, cerium, neodymium, praseodymium, erbium, thulium, yttrium and misch metal. It may be a combination of one or more rare earth elements selected from the above and samarium. R is yttrium, lanthanum, cerium,
Praseodymium, neodymium, gadolinium, terbium,
Dysprosium, holmium, erbium, thulium,
It may be ytterbium, lutetium or a mixture of two or more thereof. When the magnetic material is derived from an intermetallic compound having a tetragonal crystal structure, R may be any rare earth element, but suitable elements for R are cerium, praseodymium, neodymium, terbium, dysprosium, holmium or two of them. It is a mixture of two or more species. Particularly suitable is neodymium or praseodymium alone or in combination with other elements.

As described above, in the case of hexagonal or rhombohedral material, iron may be replaced by 50%, most preferably 33% by another element. The element is preferably a magnetic transition metal, most preferably cobalt.

In the case of tetragonal materials, as mentioned above, iron is replaced by any element of Group IIIA or IVA of the periodic table or by a transition metal not yet included in these groups.
Preferred substituents are silicon or aluminum or any transition metal, titanium, vanadium, molybdenum or chromium.

When the element X'is included in the material, it is preferably carbon, boron, silicon or zirconium, and the value of "a" may be at least 0.1 and at most 3. Preferably, the value of a + b is ≦ 3.

Component Z may be nitrogen, arsenic phosphide, antimony or bismuth or mixtures thereof, of which the particularly preferred element is nitrogen. For example, the three materials according to the first aspect of the present invention are Sm ₂ Fe ₁₇ N _2.3 and Sm.
₂ Fe ₁₇ C _1.1 N _1.1 and NdFe ₁₁ TiN _0.8 , which demonstrate the required improved magnetic properties.

The magnetic material according to the present invention exhibits significantly improved magnetic properties over conventionally known materials. That is, first,
It is to have a Curie temperature above 400 ° C. Second, it has an improved easy-direction uniaxial anisotropy, as evidenced by the X-ray diffraction pattern of the material after applying a magnetic field. Third, the magnetic moment is increasing, and finally, the magnetic moment undergoes little change with time or ambient temperature. All of these improved intrinsic magnetic properties are highly advantageous for permanent magnet applications.

As a second aspect of the present invention, a method for changing the magnetic properties of an intermetallic compound which is composed of at least one or more rare earth elements and iron, and iron is appropriately substituted with other elements. Wherein said intermetallic compound is heated with a gas containing at least one VA element Z in the substantial absence of oxygen, and said at least 1 The present invention provides a method characterized in that the seed element Z is introduced interstitially. If the intermetallic compound has a tetragonal crystal structure, the iron may be replaced by an element of Group IIIA or IVA of the periodic table or by a transition metal not yet included in these groups.

It is desirable that the sample material is placed in a closed container which can discharge oxygen, to which a reactive gas can be added, and which can be heated from the outside. The temperature can be raised to a maximum temperature not exceeding about 600 ° C. The intermetallic compound starting material is
Prior to heating in a suitable gas, for example, an ingot is suitably ground to a particle size of 0.5-50 microns in diameter. The preferred range is 0.5 to 20 microns. In order to promote the improvement of the coercive force of the modified metal material, a special additive such as niobium or vanadium may be added to reduce or eliminate free iron existing in the ingot. Alternatively, the starting material may be prepared by melt spinning in the form of thin flakes or ribbons, or by mechanical alloying or spray casting into powder. Heating may be continued for no more than 8 hours, but the exact time depends on the solid form and gas of the starting material. Therefore, the exact heating time for any starting material can be easily calculated.

Suitable gases to be used in the method of the present invention include:
Includes those that produce radicals containing monatoms of Group VA elements upon contact with high temperature surfaces such as metals or quartz, or upon exposure to high frequency radiation, including, for example, gas hydrides of Group VA elements.

Suitable magnetic materials of the present invention in which the Group VA component Z introduced into the interstitial lattice of the crystal lattice is nitrogen can be made with a suitable intermetallic starting material using gaseous nitrogen, ammonia or hydrazine. . For example, when an intermetallic compound of the formula: R ₂ Fe ₁₇ or RFe ₁₁ Ti is heated with nitrogen and the gas pressure is checked, a pressure reduction occurs, which pressure reduction starts at about 350 ° C. and reaches a temperature of 650 ° C. Continues until. The initial pressure reduction is due to the reaction of nitrogen with the exemplified intermetallic compounds and the introduction of nitrogen into the crystal lattice of R ₂ Fe ₁₇ or R (FeTi) ₁₂ . The formation of a new compound combining R, Fe and N is due to the increased weight of the sample after heat treatment and the parameter of the crystal lattice, ie unit cell volume, as shown by X-ray diffraction. Confirmed by the increase in.

The novel magnetic material manufacturing method may be performed using ammonia instead of nitrogen. In this case, a rise in pressure starting from approximately 350 ° C. is observed. This increase in pressure is explained by the decomposition of ammonia at 350 ° C. into nitrogen and hydrogen. Nitrogen is absorbed in the intermetallic sample, as evidenced by the increased weight and increased crystal lattice parameters. Once the temperature exceeds about 650 ° C., the newly formed material decomposes into α-Fe and rare earth element nitrides.

According to a third aspect of the present invention, the novel magnetic material produced as described above is used to produce a permanent magnet.

A preferred method by which this can be achieved is to grind a magnetic material with a metal such as aluminum, copper or zinc, or with a solder, organic powder or resin, apply a magnetic field to magnetically orient the material, and then It is characterized in that it is heated to a temperature at which it does not decompose. The magnetic material is preferably ground with zinc. This magnet forming method contributes to increase the coercive force, which is important for magnet formation.

Examples of the present invention will be described below.
The tables and figures below show data relating to the magnetic properties of suitable intermetallic compounds according to the invention, the examples demonstrating an improvement in the magnetic properties over known magnetic materials.

[0023]

EXAMPLES General formula: R ₂ Fe ₁₇ with respect to crystal lattice parameters, Curie temperature (Tc) and spontaneous magnetization per unit mass (σ _s ) by introducing nitrogen interstitialally into the crystal lattice The effects are shown in Table 1. These nitrogen-containing compounds were prepared by the method of heating in nitrogen gas according to the present invention.

The lattice parameters were obtained by X-ray diffraction.
Twelve kinds of rare earth elements are selected as R. The spontaneous magnetization per unit mass (σ _s ) is converted into the spontaneous magnetization per unit volume (Ms) by multiplying σ _s by the density of the magnetic material. The values marked with * in the table are estimated values.

[0025]

[Table 1] Compound structure type ac Tc σs (nm) (nm) (° C) (JT- ¹ Kg- ¹ ) Ce ₂ Fe ₁₇ Th ₂ Zn ₁₇ 0.847 1.232 -32 0 Ce ₂ Fe ₁₇ N _2.8 〃 0.873 1.265 440 160 Pr ₂ Fe ₁₇ 〃 0.857 1.242 17 82 Pr ₂ Fe ₁₇ N _2.5 〃 0.877 1.264 445 167 Nd ₂ Fe ₁₇ 〃 0.856 1.244 57 77 Nd ₂ Fe ₁₇ N _2.3 〃 0.876 1.263 459 178 Sm ₂ Fe ₁₇ 〃 0.854 1.243 116 100 Sm ₂ Fe ₁₇ N _2.3 〃 0.873 1.264 476 159 * Gd ₂ Fe ₁₇ 〃 0.851 1.243 204 46 Gd ₂ Fe ₁₇ N _2.4 〃 0.869 1.266 485 115 Tb ₂ Fe ₁₇ 〃 0.845 1.241 131 51 Tb ₂ Fe ₁₇ N _2.3 〃 0.866 1.266 460 96 Dy ₂ Fe ₁₇ Th ₂ Ni ₁₇ 0.845 0.830 94 50 Dy ₂ Fe ₁₇ N _2.8 〃 0.864 0.845 452 115 Ho ₂ Fe ₁₇ 〃 0.844 0.828 54 49 Ho ₂ Fe ₁₇ N _3.0 〃 0.862 0.845 436 115 Er ₂ Fe ₁₇ 〃 0.842 0.827 23 32 Er ₂ Fe ₁₇ N _2.7 〃 0.861 0.846 424 134 Tm ₂ Fe ₁₇ 〃 0.840 0.828 ー 13 0 Tm ₂ Fe ₁₇ N _2.7 〃 0.858 0.847 417 137 Lu ₂ Fe ₁₇ 〃 0.839 0.826 ー 18 0 Lu ₂ Fe ₁₇ N _2.7 〃 0.857 0.848 405 147 Y ₂ Fe ₁₇ 〃 0.848 0.826 52 92 Y ₂ Fe ₁₇ N _2.6 〃 0.865 0.844 421 164

The data shown in Table 1 show that there is an interstitial interstitial nitride phase R ₂ Fe ₁₇ N _b with b of about 2.6 for all rare earth series elements from Ce to Lu. The unit cell volume of the crystal lattice is 5 to 5 due to the formation of nitride.
9% increase, Curie temperature (Tc) and spontaneous magnetization (σ
It can be seen that _s ) has increased significantly. The data also show that substitution is possible between nitrides of different rare earth elements,
It is shown that the properties such as magnetization and anisotropic magnetic field can be optimized for the application in consideration of the cost of a specific rare earth element.

Crystal lattice parameters, Curie temperature (Tc) and spontaneous magnetization per unit volume (M _S ) due to interstitial introduction of nitrogen into the crystal lattice of compounds of the formulas Y ₂ Fe ₁₇ C _1.0 and Sm ₂ Fe ₁₇ C _1.1. Table 2 shows the effect on the. These novel compounds were also prepared according to the invention by heating in a nitrogen containing gas.

In the table, M _S * is the data at 18 ° C.
The numbers for Sm ₂ Fe ₁₇ C _1.1 marked with ** are easily affected by the heat treatment conditions after melting the alloy.

[0029]

[Table 2] Compound structure type ac Tc (nm) (nm) (° C) μ ₀ Ms * (T) Y ₂ Fe ₁₇ C _1.0 Th ₂ Ni ₁₇ 0.855 0.833 239 1.25 Y ₂ Fe ₁₇ C _1.0 N _1.4 〃 0.867 0.851 428 1.46 Sm ₂ Fe ₁₇ C _1.1 ** Th ₂ Zn ₁₇ 0.858 1.244 207 1.11 Sm ₂ Fe ₁₇ C _1.1 N _1.1 〃 0.873 1.270 471 1.53

From the data shown in Table 2, the general formula R _x Fe
the interstitial type introduction of nitrogen into the crystal lattice of _y X 'compounds of _a, the magnetic properties, Tc, it can be seen that improved magnetization and the unit cell volume.

The data in Table 3 show that the easy-direction uniaxial anisotropy is improved by taking a compound in which R is samarium as an example. The easy-direction uniaxial anisotropy value (Tesla) represented by the anisotropic magnetic field B _a is obtained by orienting the C-axis of the rhombohedron in the magnetic field direction. B shown in this table
The value of _a is determined from the magnetization curve of the oriented powder obtained by adding a vertical and parallel to the magnetic field in the orientation direction.

[0032]

Table 3 Compound Ba (T) Sm ₂ Fe ₁₇ <1.0 Sm ₂ Fe ₁₇ N _2.3 > 12.0 Sm ₂ Fe ₁₇ C _1.1 4.0 Sm ₂ Fe ₁₇ C _1.1 N _1.0 > 8.0

The data in Table 4 show that Fe--Fe and F based on the change in Curie temperature for different heavy rare earth elements.
The inference value about the interaction of e-rare earth element exchange is shown.

[0034]

Table 4 Compound ⁿ R-Fe (μo) ⁿ Fe-Fe (μo) R ₂ Fe ₁₇ 225 181 R ₂ Fe ₁₇ N _y 208 515

It can be seen that the Fe-Fe interaction is enhanced by a factor of 2.5 with the new nitride compound, while the Fe-rare earth element interaction is slightly reduced.

The data shown in Table 5 has the general formula: RFe ₁₁ T
The effect on the crystal lattice parameters (a and b), Curie temperature (Tc), average hyperfine magnetic field (B _hf , Tesla) and anisotropy by the interstitial introduction of nitrogen into the crystal lattice of the compound represented by i Show. The starting materials were prepared according to the invention by heating in a nitrogen containing gas. The individual treatment conditions for each sample are shown in the same table.

[0037]

[Table 5] Compound a (nm) c (nm) Tc (° C) Bhf (T) anisotropic treatment Nd (Fe ₁₁ Ti) 0.856 0.478 270 21.5 c-axis Nd (Fe ₁₁ Ti) N _0.7 0.879 0.487 475 28.0 c Axis N ₂ at 450 ° C for 40 minutes Sm (Fe ₁₁ Ti) 0.855 0.479 311 25.5 c-axis Sm (Fe ₁₁ Ti) N _0.8 0.864 0.484 496 29.1 c-plane N ₂ at 480 ° C for 30 minutes Sm (Fe ₁₁ Ti) N _0.9 0.865 0.486 490 Heating in NH ₃ @ 10 ° / min up to 550 ° C Dy (Fe ₁₁ Ti) 0.850 0.478 257 24.4 c-axis Dy (Fe ₁₁ Ti) N _0.6 0.867 0.480 473 28.2 c-axis in N ₂ at 450 ° C 60 minutes Tb (Fe ₁₁ Ti) 0.852 0.479 281 24.2 c-axis Tb (Fe ₁₁ Ti) N _0.5 0.864 0.482 477 28.5 c-axis N ₂ 40 minutes at 450 ° C Y (Fe ₁₁ Ti) 0.851 0.479 251 23.5 c-axis Y ( Fe ₁₁ Ti) N _0.8 0.862 0.481 460 28.8 c-axis N ₂ in 480 ° C for 60 minutes

Further, the general formulas R ₂ Fe ₁₇ , R ₂ Fe
_{17 X 'a, R (FeM} ) 12, or R ₂ (FeM) ₁₇ (wherein, M is a substituted element described above) VA group elements of the periodic table to a particular intermetallic compound represented by (the The example is nitrogen) and the improvement in magnetic properties achieved thereby is illustrated by the data shown in the drawings.

FIG. 1 is a temperature-pressure curve for nitrogen gas absorption by Y ₂ Fe ₁₇ , and shows that the gas pressure in the reaction chamber decreases because nitrogen is taken into the sample.
The pressure value during cooling indicates that the absorption of nitrogen by the Y ₂ Fe ₁₇ sample is continuing.

FIG. 2 shows 400 ° C., 450 ° C. and 500 ° C.
Shows the isothermal reaction of nitrogen with Y ₂ Fe ₁₇ powder having an average particle diameter of about 2 μ, the y value being the number of moles of nitrogen atoms introduced into 1 mole of sample. These data show that the optimum temperature range for practicing the method of the present invention is between about 450 ° C and 600 ° C.

FIG. 3 shows Y ₂ Fe _{17 in} an atmosphere of about 1 bar.
Figure 3 shows a temperature-pressure curve for the absorption of ammonia gas by. The heating curve shows the pressure increase due to the uptake of nitrogen from ammonia. After heating the sample to 550 ° C, a weight gain is observed, which is due to nitrogen absorption.

FIG. 4 shows ⁵⁷ Fe Moessbauer spectra at room temperature before (a) and after heating (b) Y ₂ Fe ₁₇ in ammonia at 1 bar to 500 ° C. Changes in Curie temperature and magnetic moment, ⁵⁷ Fe Mössbauer reflected in the spectrum, the average hyperfine field at 20 ℃ (B _hf) is Y ₂ Fe ₁₇ N _2.6 10 Tesla of Y ₂ Fe ₁₇
Increase to 30 Tesla.

FIG. 5 shows Y ₂ Fe ₁₇ powder in a temperature and pressure analyzer in nitrogen at 10 ° C./min at 500 ° C., 550 ° C., 600 ° C., 7 ° C.
The X-ray-diffraction pattern at the time of respectively heating to 00 degreeC and 850 degreeC is shown. The powder represented by the general formula R ₂ Fe ₁₇ (R is another rare earth element) also exhibits similar behavior.

As is clear from the figure, after the treatment up to 550 ° C., a phase having an expansion lattice parameter that coexists with the non-expansion phase appears. The Y ₂ Fe ₁₇ N _2.6 phase clearly _forms at 600 ° C. and when heated to 700 ° C. or higher, the alloy becomes Y
Decomposes into N and αFe.

FIG. 6 shows Y ₂ Fe ₁₇ powder in nitrogen gas at 50
2 shows an X-ray diffraction pattern after isothermal heating at 0 ° C. for 2 hours. The Y ₂ Fe ₁₇ N _2.6 compound is produced at a temperature lower than the temperature shown in the figure by heat treatment for a long time, but further heat treatment up to 850 ° C. decomposes into YN and αFe.

FIG. 7 shows a temperature-pressure curve for Y ₂ Fe ₁₇ C _1.0 heated from room temperature in an ammonia atmosphere of about 1 bar. Also in this case, a pressure increase is observed at about 370 ° C.

FIG. 8 shows (a) Curie temperature Tc (° C.) and (b) unit cell volume of crystal lattice for Y ₂ Fe ₁₇ C.
It shows the dependence of V (Å ³ ) on the maximum heating temperature. Two R ₂ F for samples treated at 450 ° C and 500 ° C
The e ₁₇ type phase coexists, one having a large unit cell volume and a high Curie temperature, while the other has a smaller unit cell volume and a low Curie temperature. The larger the crystal lattice, the higher the Curie temperature. Also, the spontaneous magnetic moment (μ ₀ M _S ) greatly increases to 1.46 Tesla (see Table 2).

FIG. 9 shows Y ₂ Fe ₁₇ C _1.0 in 1 bar of ammonia before heating at 550 ° C. (a) and after heating (b).
The Moessbauer spectrum at room temperature of is shown. The average hyperfine magnetic field (B _hf ) at 18 ° C. is 25.
Increase from 3 Tesla to 30.8 Tesla.

FIG. 10 shows a temperature-pressure curve when Sm ₂ Fe ₁₇ C _1.1 was heated from room temperature in an ammonia atmosphere of about 1 bar. Again, there is a pressure rise at about 350 ° C. After heating to 600 ° C., analysis of the sample revealed that the material was rhombohedral (Th ₂ Zn ₁₇
It was found that the (type) structure was maintained. From the mass increase, the nitrogen content is estimated to be 1.1 nitrogen atoms per Sm ₂ Fe ₁₇ C _1.1 formula unit.

In FIG. 11, before orienting a magnetic field of 1.2 Tesla to Sm ₂ Fe ₁₇ C _1.1 N _1.1 powder for 1 hour (a)
And the X-ray diffraction pattern of (b) is shown. As is clear from the figure, particularly strong uniaxial anisotropy is exhibited when R is samarium.

FIG. 12 shows 600 ° C. in 1 bar of ammonia.
Sm ₂ Fe ₁₇ C before (a) and after (b) heat treatment
The magnetization curve of the oriented sample of _1.1 at 18 ° C is shown. The curves are for a magnetic field applied parallel to the orientation axis (‖) and a magnetic field applied perpendicular to the orientation axis (⊥). From these magnetization curves, the μ ₀ M _S value shown in Table 2 and the B _a value shown in Table 3 are obtained.

FIG. 13 (a) Sm ₂ F having an average particle size of 1 μm
Although the same powder was heated at 500 ° C. in nitrogen gas to form a e ₁₇ powder and _{(b) Sm 2 Fe 17 N} 2.4 shows the X-ray diffraction pattern.

14a and 14b show the radial distribution function obtained from the extended X-ray absorption fine structure data for the same sample as in FIG. The peak appearing at 2.5Å indicates that there are almost three nitrogen atoms at 2.5Å from the samarium atom in the nitride.

FIGS. 15a and 15b show the crystal structures of the rhombohedral and hexagonal 2:17 structures, showing the positions occupied by nitrogen. Figure 15a is a rhombohedral crystal structure,
Figure 15b is a hexagonal crystal structure. Large circles represent rare earth elements, small shaded circles represent iron, and smaller black circles represent nitrogen positions 9e, 6h.

FIG. 16 shows a typical Sm ₂ used for nitrogen absorption.
It is a frequency distribution diagram of a particle size distribution of Fe ₁₇ powder.

FIG. 17 shows the change in the diffusion coefficient of nitrogen in the Sm ₂ Fe ₁₇ powder as a function of the reciprocal of temperature.

FIG. 18 shows Sm ₂ after treatment with ammonia.
Shows the magnetization curve at 18 ° C. for oriented specimen of Fe ₁₇ N _{2. 3.} Again, the curves are shown for the case of applying a magnetic field parallel to the orientation axis (‖) and for the case of applying a magnetic field perpendicular to the orientation axis (⊥). From these magnetization curves, the value of anisotropic magnetic field B _a is obtained as shown in Table 3.
The value of B _a for Sm ₂ Fe ₁₇ N _{2. 3} is a> 12 Tesla, but in practice the curve shown in the figure indicates that it may also around 20 tesla.

FIG. 19 shows a temperature-pressure curve, and (a) shows S.
m ₂ Fe ₁₇ cast ingot powder heated in nitrogen, (b) powder made of ingot and annealed at 950 ° C. for 100 hours heated in nitrogen. . The difference between the two curves is R
_It has been demonstrated that the processing temperature required to form the ₂ Fe ₁₇ N _b phase depends on the metallurgical composition of the ingot used to make the powder.

FIG. 20 shows the compounds Nd ₂ Fe ₁₇ N _2.3 and Sm _2
2 shows X-ray diffraction patterns after applying a magnetic field of 1.2 Tesla to Fe ₁₇ N _2.3 and Er ₂ Fe ₁₇ N _2.7 . Sm ₂ Fe ₁₇
In the case of N _2.3 , the C axis is oriented parallel to the applied magnetic field and exhibits strong uniaxial anisotropy. However, when R is Nd or Er, the C axis tends to be oriented perpendicular to the direction of the applied magnetic field.

FIG. 21 shows the crystal structure of a cubic system 1:12 compound and shows the position occupied by nitrogen. The meaning of the circle is the same as in FIGS. 15a and 15b.

FIG. 22 shows a temperature / pressure locus for nitrogen gas absorption by Sm (Fe ₁₁ Ti). The material was heated in nitrogen at about 1 bar at a rate of 10 ° C / min. It can be seen from the figure that the optimum temperature range for the processing operation is similar to that of the R ₂ Fe ₁₇ compound.

FIG. 23 shows Sm (Fe ₁₁ Ti) according to the present invention.
Fig. 7 shows ⁵⁷ Mossbauer spectra at room temperature before (a) and after heating (b) in a nitrogen-containing gas. The average hyperfine magnetic field (B _hf ) increased from 25.5 Tesla before the treatment (a) to 29.1 Tesla after the treatment (b), reflecting changes in the Curie temperature and the magnetic moment.

FIG. 24 shows (a) Sm (Fe ₁₁ Ti) and (b) Sm (Fe ₁₁ T) oriented in a magnetic field of 1.2 Tesla.
i) X-ray diffraction pattern for N _0.8 powder.
The strong uniaxial anisotropy of Sm (Fe ₁₁ Ti) is due to the interstitial nitride S
In m (Fe ₁₁ Ti) N _0.8 , the easy plane anisotropy changes, which proves the change in the sign of the quadratic crystal magnetic coefficient A ₂₀ from negative to positive. Therefore, the strong uniaxial anisotropy is 1: of the interstitial interstitial transformation of rare earth elements having a negative Stevens coefficient α _J (Nd, Er, Tm), especially neodymium.
It was observed for compounds having a 12-type structure.

FIG. 25 illustrates interstitial nitrogen atoms around a rare earth element in (a) a rhombohedral or hexagonal 2:17 structure and (b) a tetragonal 1.12 structure. The slope of the electric field experienced by the rare earth element, quantified by the parameter A ₂₀ , is mainly caused by the surrounding interstitial atoms in the material of the invention. This is negative in the atomic arrangement of the 2:17 type compound and positive in the atomic arrangement of the 2:12 type compound.

26 to 28 show some effects of cobalt substitution of iron in the material of the present invention having a rhombohedral or hexagonal crystal structure.

FIG. 26 shows the general formula: R ₂ (Fe _{17 -C} Co
_c N _b ), where c is the number of cobalt atoms, is a nitrogen content achieved by treating a finely ground powder in nitrogen gas at a temperature in the range of 400-600 ° C.

FIG. 27 shows transition metal substitution (R is Y, c = 0.
By 2), it is shown that the maximum region of magnetization is wide.

FIG. 28 shows that the transition metal substituent surely contributes to the anisotropy when c> 0.1.

FIG. 29 illustrates the improved hysteresis of Sm ₂ Fe ₁₇ N _2.3 powder, including the demagnetization curves of the first and second quadrants of samples oriented and magnetized with a pulsed magnetic field of 8 Tesla. The displayed data is as follows. (A)
Sm ₂ Fe ₁₇ N _2.3 powder dispersed in epoxy resin,
(B) Sm ₂ F crushed with Zn powder (25 wt%)
e ₁₇ N _2.3 powder, (c) Zn powder (15 wt%) was pulverized, and Sm ₂ Fe ₁₇ N was heat-treated at 400 ° C. for 2 hours.
_2.3 powder.

FIG. 29 shows the magnetic characteristics of the magnetic material and the permanent magnet manufactured by the method of improving the coercive force and the hysteresis according to the present invention. For example, in FIG. 29C, when a magnetic material is pulverized with 15 wt% Zn and heated to 400 ° C., a magnet having a coercive force of 0.5 Tesla and a maximum energy product of 86 KJm ⁻³ is obtained.

Finally, the data shown in FIG. 29 demonstrates that Sm ₂ Fe ₁₇ N _2.3 and related compounds according to the present invention can be effectively processed to make magnets.

Furthermore, the thin film of the magnetic material of the present invention can be used for magnetic or magnetic-optical recording.

[0073]

As described above, according to the present invention,
A new magnetic material having a high Curie temperature of 400 ° C. or higher, excellent uniaxial anisotropy in the easy direction and a large magnetic moment, and excellent magnetic properties such as temporal change of the magnetic moment and very little temperature dependence is obtained. By using it, an excellent effect that a permanent magnet having good characteristics can be manufactured can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing a temperature-pressure curve for nitrogen gas absorption by Y ₂ Fe ₁₇ .

FIG. 2 is a diagram showing the amount of nitrogen introduced into 1 mol of Y ₂ Fe ₁₇ powder by an isothermal reaction at 400 ° C., 450 ° C. and 500 ° C. in nitrogen.

FIG. 3 is a diagram showing a temperature-pressure curve for absorption of ammonia gas by Y ₂ Fe ₁₇ .

FIG. 4 shows the ⁵⁷ Fe Moessbauer spectra at room temperature before (a) and after heating (b) Y ₂ Fe ₁₇ to 500 ° C. in an ammonia atmosphere of 1 bar.

FIG. 5 is a diagram showing an X-ray diffraction pattern when Y ₂ Fe ₁₇ is heated in nitrogen.

FIG. 6 Y ₂ Fe ₁₇ powder in nitrogen gas at 500 ° C.
It is a figure which shows the X-ray-diffraction pattern after heating for time.

FIG. 7 shows a temperature-pressure curve for Y ₂ Fe ₁₇ C _1.0 heated from room temperature in an ammonia atmosphere of about 1 bar.

FIG. 8 is a diagram showing the dependence of Curie temperature Tc and unit cell volume V of Y ₂ Fe ₁₇ C on the maximum heating temperature.

FIG. 9 shows Mössbauer spectra at room temperature before (a) and after (b) heating Y ₂ Fe ₁₇ C _1.0 in 1 bar of ammonia.

FIG. 10 is a diagram showing a temperature-pressure curve when Sm ₂ Fe ₁₇ C _1.1 was heated from room temperature in an ammonia atmosphere of about 1 bar.

FIG. 11 is a diagram showing X-ray diffraction patterns before (a) and after (b) orienting Sm ₂ Fe ₁₇ C _1.1 N _1.1 powder.

FIG. 12: 18 of oriented samples of Sm ₂ Fe ₁₇ C _1.1 before (a) and after (b) heat treatment in 1 bar ammonia.
It is a figure which shows the magnetization curve in ° C.

FIG. 13 is a diagram showing an X-ray diffraction pattern of Sm ₂ Fe ₁₇ powder (a) and the same powder heated in nitrogen gas at 500 ° C. for 2 hours to form Sm ₂ Fe ₁₇ N _2.4 (b). Is.

FIG. 14 is a diagram showing a radial distribution function obtained from extended X-ray absorption fine structure data for the same sample as in FIG.

FIG. 15 is a diagram showing crystal structures of a rhombohedral system (a) and a hexagonal system (b).

FIG. 16 is a frequency distribution diagram of particle size distribution of a typical Sm ₂ Fe ₁₇ powder used for nitrogen absorption.

FIG. 17 is a diagram showing changes in the diffusion coefficient of nitrogen in Sm ₂ Fe ₁₇ powder as a function of the reciprocal of temperature.

FIG. 18: Sm ₂ Fe after treatment with ammonia
₁₇ N _2. Shows the magnetization curve at 18 ° C. for ₃ orientations sample.

FIG. 19 shows a powder made of a cast iron ingot of Sm ₂ Fe ₁₇ heated in nitrogen (a) and a powder made of an ingot and annealed at 950 ° C. for 100 hours and heated in nitrogen (b). It is a figure which shows the temperature pressure curve of.

FIG. 20 is a diagram showing an X-ray diffraction pattern after applying a magnetic field of 1.2 Tesla to Nd ₂ Fe ₁₇ N _2.3 , Sm ₂ Fe ₁₇ N _2.3, and Er ₂ Fe ₁₇ N _2.7 .

FIG. 21 is a diagram showing a crystal structure of a cubic 1:12 compound.

FIG. 22 is a diagram showing a temperature / pressure locus for nitrogen gas absorption by Sm (Fe ₁₁ Ti).

FIG. 23 is a diagram showing ⁵⁷ Mossbauer spectra at room temperature before (a) and after (b) heating Sm (Fe ₁₁ Ti) in a nitrogen-containing gas.

FIG. 24 (a) S oriented in a magnetic field of 1.2 Tesla
m (Fe ₁₁ Ti) and (b) Sm (Fe ₁₁ Ti) N
It is a figure which shows the X-ray diffraction pattern about _0.8 powder.

FIG. 25 is a diagram showing interstitial nitrogen atoms around a rare earth element in (a) a rhombohedral or hexagonal structure and (b) a tetragonal 1:12 structure.

FIG. 26 is a diagram showing a relationship between a cobalt substitution amount and a nitrogen content in an R ₂ (Fe _17-C Co _c N _b ) type fine powder.

FIG. 27 is a diagram showing a relationship between cobalt substitution amount and magnetization.

FIG. 28 is a diagram showing the relationship between the cobalt substitution amount and anisotropy.

FIG. 29 is a diagram showing a change in hysteresis of Sm ₂ Fe ₁₇ N _2.3 powder by various treatments, (a) Sm ₂ Fe ₁₇ N _2.3 powder dispersed in epoxy resin, (b) Zn powder (25 wt% ) With Sm ₂ Fe ₁₇ N _2.3 powder,
(C) Grinded together with Zn powder (15 wt%), 400 ° C.
FIG. 3 is a diagram showing demagnetization curves of Sm ₂ Fe ₁₇ N _2.3 powder heat-treated for 2 hours in FIG.

 ─────────────────────────────────────────────────── ─── Continued Front Page (71) Applicant 591079890 The Probast Fellows and Scalars of the Carriage of the Holly and Undivided Trinity of Queen Elli Zabeth near Dublin THE PROVEST, FELLOW S AND SCHOLARS OF T HE COLLEGE OF THE H HOLY AND UNDIVIDED T RINITY OF QUEEN ELI ZABETH NEAR LABEL, ZABETH NEAR David Koay, Hilve, Cast Leknock, County Dublin, Ireland Click House (no indication of address) (72) inventor Hong Sun Ireland, Dublin Dublin 9, U Ittowasu Road No. 46

Claims (31)

[Claims] 1. A general formula: R _x F derived from an intermetallic compound having a rhombohedral, hexagonal or tetragonal crystal structure.
A magnetic material represented by e _{y X'a} Z _b . However, in the formula, R is one or more rare earth elements, and X'is IIIA, IIIB, IVA in the periodic table.
Alternatively, an element of IVB group, Z is one or more elements of VA group of the periodic table, x is a value of 0.5 to 2, y is a value of 9 to 19, a is a value of 0 to 3, and b is 0.3. And the magnetic material represented by the above general formula is derived from an intermetallic compound having a rhombohedral or hexagonal crystal structure, Fe
Is not substituted or partially substituted with another element, and when the magnetic material represented by the above general formula is derived from an intermetallic compound having a tetragonal crystal structure, Fe is II of the periodic table.
In the case of a magnetic material partially substituted with any element of Group IA or Group IVA or a transition metal of another group and further derived from the rhombohedral or hexagonal crystal structure, the component Z is antimony or In the case of bismuth, the condition is that the element X'is not boron. 2. The magnetic material according to claim 1, wherein the magnetic material represented by the general formula is derived from an intermetallic compound having a tetragonal crystal structure, and a = 0. 3. The magnetic material according to claim 1, wherein R is samarium or neodymium. 4. The magnetic material according to claim 1, wherein the magnetic material represented by the general formula is derived from a rhombohedral or hexagonal intermetallic compound, and R is samarium. material. 5. The magnetic material represented by the general formula is derived from a rhombohedral or hexagonal intermetallic compound, and R is samarium and yttrium, lanthanum, cerium, neodymium, praseodymium, erbium,
The magnetic material according to claim 1, which is a combination with one or more rare earth elements selected from thulium and misch metal. 6. The magnetic material represented by the general formula is derived from a rhombohedral or hexagonal intermetallic compound, wherein R is yttrium, lanthanum, cerium,
Praseodymium, neodymium, gadolinium, terbium,
Dysprosium, holmium, erbium, thulium,
The magnetic material according to claim 1, which is ytterbium or lutetium or a mixture of two or more thereof. 7. The magnetic material is derived from an intermetallic compound having a tetragonal crystal structure, wherein R is yttrium, thorium, cerium, praseodymium, neodymium, terbium, dysprosium or holmium or two or more thereof. The magnetic material according to claim 1, 2 or 3, which is a mixture of 8. The magnetic material according to claim 1, wherein Fe is replaced by transition metal in an amount of 33% or less. 9. The magnetic material according to claim 8, wherein the magnetic material represented by the general formula is derived from a rhombohedral or hexagonal intermetallic compound, and the transition metal is cobalt. 10. The magnetic material is derived from an intermetallic compound having a tetragonal crystal structure, and Fe is partially substituted with titanium, vanadium, molybdenum or chromium. And the magnetic material according to any one of 7. 11. The magnetic material is derived from an intermetallic compound having a tetragonal crystal structure, and Fe is partially substituted with aluminum or silicon.
The magnetic material according to any one of 3 and 7. 12. The magnetic material of the general formula is derived from a rhombohedral or hexagonal intermetallic compound, wherein X ′ is carbon, boron, silicon or zirconium, and a is 0. The value is a value from 1 to 3,
7. The magnetic material according to any one of 3, 4, 5 and 6. 13. The magnetic material according to claim 12, wherein a + b ≦ 3. 14. The magnetic material according to claim 1, wherein Z is nitrogen. 15. The magnetic material according to claim 1, wherein the component Z comprises nitrogen and at least one VA group element. 16. The magnetic material according to claim 1, wherein the component Z is one or more of P, As, Sb and Bi. 17. A composition formula Sm ₂ Fe ₁₇ N _2.3 , Sm ₂ Fe
The magnetic material according to claim 14, having ₁₇ C _1.1 N _1.1 or NdFe ₁₁ TiN _0.8 . 18. A method for improving the magnetic properties of an intermetallic compound comprising at least one rare earth element and iron, wherein iron is partially substituted by another element, wherein the intermetallic compound is at least one species. Of the VA group element Z is substantially heated in the absence of oxygen to introduce the at least one VA group element Z into the crystal lattice of the intermetallic compound by interstitial penetration. A method characterized by the following. 19. The intermetallic compound having a tetragonal crystal structure, wherein iron is substituted with an element of Group IIIA or IVA of the periodic table or a transition metal of another group.
The method according to 8. 20. Group VA element Z due to contact of the gas with a hot surface of a metal or quartz or by exposure to radio frequency radiation.
20. The method according to claim 18 or 19, which is a gas that generates radicals containing a plurality of monatoms. 21. The method of claim 20, wherein the gas is a gas hydride of Group VA element Z. 22. The method according to claim 18, wherein the magnetic material according to claim 1 is manufactured. 23. The method of claim 20, wherein the Group VA element Z is nitrogen and the gas is nitrogen, ammonia or hydrazine. 24. The method according to claim 18, wherein the intermetallic compound is heated to a temperature of 650 ° C. or lower. 25. The method according to claim 18, wherein the intermetallic compound is pulverized into particles having a diameter of 1 to 50 μm. 26. The method according to claim 25, wherein the ground intermetallic compound is heated for 8 hours or less. 27. A method according to any one of claims 1 to 1 for producing a permanent magnet.
8. A method of using the magnetic material according to any one of 7. 28. (a) The magnetic material is aluminum
A step of pulverizing with a metal such as copper or zinc, or an organic powder or a resin, (b) a step of magnetically aligning the magnetic material by applying a magnetic field, and (c) a temperature sufficiently low to prevent decomposition of the magnetic material. 28. The use according to claim 27, wherein the magnet is produced by a method comprising the step of heating the ground product. 29. In the magnet manufacturing process, the magnetic material is added to
29. Use according to claim 28, grinding with 20% by weight of zinc. 30. A permanent magnet made of the magnetic material according to claim 1. 31. A permanent magnet made of a magnetic material produced by the method according to claim 18.