JP2002329603A - Magnetic solid material and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid material which is used for a solid magnet, has superior magnetic characteristic, is high in density, thermal stability, and oxidation resistance, and solidified by metallic bond. SOLUTION: Material powder consisting rare earth-iron-nitrogen-hydrogen magnetic material that a rhombohedral or a hexagonal crystal structure is formed into a molded body by compaction, and the molded body is shock- compressed and solidified into the solid material for magnet by the use of underwater shock waves.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a solid material for a rare earth-iron-nitrogen-hydrogen magnet having high density, high magnetic properties, and excellent thermal stability and oxidation resistance. The present invention further provides:
After compacting magnetic material powder, it is further subjected to impact compression to obtain high density and high performance permanent magnet while preventing decomposition and denitrification.
The present invention relates to a method for producing a solid material for a magnet.

[0002] The term "high density" as used herein means a density exceeding 80% by volume relative to the true density of the raw material magnetic powder. The high performance herein means that at least one of saturation magnetization, residual magnetization or residual magnetic flux density, coercive force, squareness, and maximum energy product [(BH) _max ] is higher than that of a conventional rare earth-iron-nitrogen magnet. Higher stability, or having higher stability than conventional rare earth-iron-nitrogen magnets. Furthermore, the solid material for a magnet referred to here refers to a massive magnetic material, and in the present application, powders of the magnetic material constituting the solid material for a magnet are continuously connected directly or via a metal phase or an inorganic phase. It is a magnetic material that is in a state of being combined as a whole and forming a lump as a whole.

[0003]

2. Description of the Related Art As a high performance rare earth magnet, for example, Sm
-Co-based magnets and Nd-Fe-B-based magnets are known.
The former is widely used because of its high thermal stability and corrosion resistance, and the latter is widely used because of its extremely high magnetic properties, low cost, and stable supply of raw materials. Today, rare earth magnets having both higher thermal stability and higher magnetic properties and lower raw material costs are demanded as actuators for electrical equipment and various FAs, or as magnets for rotating machines.

On the other hand, when a rare earth-iron compound having a rhombohedral or hexagonal crystal structure is reacted at a relatively low temperature of 400 ° C. to 600 ° C. in a mixed gas of NH ₃ and H ₂ , N
It has been reported that atoms and H atoms penetrate into interstitial positions of the above crystal, for example, a Th ₂ Zn ₁₇ type compound, resulting in a remarkable increase in Curie temperature and magnetic anisotropy (US Pat. No. 5,186,766). . In recent years, such rare earth-iron-nitrogen based magnetic materials are expected to be put to practical use as new magnet materials meeting the above demand.

[0005] Rare earth-iron-nitrogen-hydrogen-based materials (hereinafter referred to as R-Fe-NH-based magnetic materials) having nitrogen and hydrogen between lattices of an intermetallic compound and having a rhombohedral or hexagonal structure are known. , Generally obtained in the form of powder,
At a temperature of 0 ° C. or higher, it is easily decomposed into an α-Fe decomposition phase and a rare earth nitride, and it is extremely difficult to obtain a solid material for a magnet by sintering by self-sintering using ordinary industrial methods. .

Therefore, as a magnet using an R-Fe-NH-based magnetic material, a bonded magnet using a resin as a binder has been produced and used. However, magnets made from such materials often have a Curie temperature of 400 ° C. or higher, and despite the use of magnetic powder that does not lose magnetization even at temperatures of 200 ° C. or higher, resin One of the major reasons is that the heat resistance temperature of the binder is low, and the irreversible demagnetization rate increases. In other words, in response to recently high load requirements,
When producing a brushless motor or the like as a power source used in a high-temperature environment of 150 ° C. or more, there is a problem that the bonded magnet cannot be used.

In the case of manufacturing a compression-molded bonded magnet using a resin as a binder, a molding pressure of 10 tons / cm ² or more, which is industrially difficult, is required to improve the filling rate and improve the performance. In consideration of the mold life and the like, the mixing ratio is often forced to be 80% or less in volume ratio. Depending on the compression-molded bonded magnet, R-Fe-N-H
There is a problem that the excellent basic magnetic properties of the system magnetic material cannot be sufficiently exhibited. That is, a bonded magnet made of an R—Fe—N—H based magnetic material is a conventional Sm—Co
There is a problem that the original high thermal stability and magnetic properties cannot be sufficiently exhibited as compared with the Nd-Fe-B sintered magnet and the like.

[0008] In order to solve the above problems, Japanese Patent No. 31001
No. 08232 proposes a method for manufacturing a permanent magnet. However, according to the method, the residual temperature Th ₂ Zn ₁₇ type rare earth after impact compression - iron - to suppress below the decomposition temperature of the nitrogen based magnetic material is smaller the maximum pressure during the impact compression of a range There was a problem that must be limited to. This is because when a conventional shock wave is used, the temperature of the magnetic material is kept high for a long time despite the short duration of the shock wave itself, so that the magnetic material is very easily decomposed. is there.

[0009]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a solid material for a rare earth-iron-nitrogen-hydrogen magnet having high density, high magnetic properties, excellent thermal stability and oxidation resistance, and a solid material thereof. It is to provide a manufacturing method.

[0010]

Means for Solving the Problems The present inventors have conducted intensive studies on the above-mentioned problems, and as a result, have found that hydrogen is contained in a rare earth-iron-nitrogen based magnetic material powder having a rhombohedral or hexagonal crystal structure. After forming into a green compact in a magnetic field or without a magnetic field, it is shock-compressed and solidified using an underwater shock wave, and takes advantage of the characteristics of shock compression such as ultra-high-pressure shearing properties, activation, and short-time phenomena. Mainly contains the R-Fe-NH-based magnetic material by suppressing the remaining temperature below the decomposition temperature of the R-Fe-N-H-based magnetic material (about 600 ° C at normal pressure) to prevent the decomposition. It has been found that a high-density solid material for magnets can be obtained, and the present invention has been completed. Further, the present inventors further found that when the underwater shock wave was used, RF
The inventors have also found that the e-N-H based magnetic material can be easily integrated with a soft magnetic powder or solid, or a nonmagnetic material powder or solid, and have completed the present invention. The solid material for a magnet of the present invention does not contain a binder such as a resin.

That is, aspects of the present invention are as follows. (1) R-Fe having a rhombohedral or hexagonal crystal structure
-A solid material for a magnet containing 50 to 100% by volume of an NH magnetic material. (2) The solid material for a magnet according to the above (1), wherein R-
The Fe-NH-based magnetic material has a general formula of R _α Fe _100-α-β-γ
Expressed in _N β H _γ, R is at least one element selected from rare earth elements including Y, also, α, β, γ are in atomic percent, 3 ≦ α ≦ 20,5 ≦ β ≦ 30, 0.01 ≦ γ
A solid material for a magnet, wherein ≦ 10. (3) The solid material for a magnet according to the above (1) or (2), wherein 10 atomic% or less of R and / or Fe is Ni, T
i, V, Cr, Mn, Zn, Cu, Zr, Nb, Mo,
Ta, W, Ru, Rh, Pd, Hf, Re, Os, Ir
A solid material for a magnet, wherein the material is substituted with at least one element selected from the group consisting of: (4) The solid material for a magnet according to any one of (1) to (3), wherein at least 10 atom% of N and / or H is selected from C, P, Si, S, and Al. A solid material for a magnet, characterized by being substituted with the element of (5) wherein (1) a solid material for a magnet according, represented by the general formula _{R α Fe 100-α-β} -γ -δ N β H γ M δ, R
Is at least one element selected from rare earth elements including Y, and M is Li, Na, K, Mg, Ca, Sr, B
a, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo,
W, Mn, Pd, Cu, Ag, Zn, B, Al, Ga,
At least one element selected from In, C, Si, Ge, Sn, Pb, and Bi and / or an oxide, fluoride, carbide, nitride, hydride, carbonate, sulfate, silicate, silicate, or chloride of R And at least one selected from nitrates, and α, β, γ, and δ are mole percentages and 3 ≦ α ≦ 2
0, 5 ≦ β ≦ 30, 0.01 ≦ γ ≦ 10, 0.1 ≦ δ ≦
40. A solid material for a magnet, which is 40. (6) The solid material for a magnet according to any one of the above (1) to (5), wherein 50 atom% or more of R is Sm. (7) The solid material for a magnet according to any one of the above (1) to (6), wherein 0.01 to 50 atomic% of Fe is substituted with Co. (8) The solid material for a magnet according to any one of (1) to (7), wherein the soft magnetic material containing at least one element selected from Fe, Co, and Ni is uniformly dispersed and integrated. A solid material for a magnet, comprising: (9) The solid material for a magnet according to any one of (1) to (8), wherein at least one selected from a rare earth-iron-boron magnetic material, a rare earth-cobalt magnetic material, and a ferrite magnetic material. A solid material for magnets, wherein a kind of magnetic material is uniformly added, mixed and integrated. (10) The solid material for a magnet according to any one of the above (1) to (9), wherein a non-magnetic phase is present at a grain boundary of the magnetic material. (11) A solid magnet material, wherein the solid magnet material according to any one of (1) to (10) and a soft magnetic solid metal material are joined and integrated. (12) The solid material for a magnet according to any one of the above (1) to (11), which has a soft magnetic layer, and is alternately laminated with the soft magnetic layer to be integrated. Solid material for magnets. (13) The solid material for a magnet according to any one of the above (1) to (12), wherein at least a part thereof is covered with a non-magnetic solid material. (14) The solid material for a magnet according to any one of the above (1) to (13), which is provided with magnetic anisotropy. (15) The solid material for a magnet according to any one of the above (1) to (14), which is formed into a columnar shape, a cylindrical shape, a ring shape, a disk shape, or a flat shape. Solid material. (16) The solid material for a magnet according to any one of the above (1) to (15), wherein the solid material for a magnet is subjected to impact compression and solidification using an underwater shock wave. (17) The method for producing a solid material for a magnet according to any one of the above (1) to (15), wherein compaction of the raw material powder is performed in a magnetic field. Production method. (18) The method for producing a solid material for a magnet according to (16), wherein the raw material powder is compacted, and then subjected to impact compression and solidification using an underwater shock wave. Manufacturing method. (19) The method for producing a solid material for a magnet according to (16), wherein the raw material powder is compacted in a magnetic field.
A method for producing a solid material for a magnet, wherein the material is subjected to impact compression and solidification using an underwater shock wave. (20) A method for producing the solid material for a magnet according to the above (15), wherein the solid material for a magnet is formed by cutting and / or plastic working. (21) The method for producing a solid material for a magnet according to any one of the above (17) to (20), comprising a step of heat-treating the material at least once at a temperature of 100 ° C. or higher and lower than a decomposition temperature. A method for producing a solid material for a magnet, comprising:

Hereinafter, the present invention will be described in detail. The solid material for a magnet of the present invention can be produced by compressing and solidifying a raw material molded body using a shock wave pressure of an underwater shock wave. By compressing and solidifying using an underwater shock wave having a shock wave pressure of 3 to 40 GPa, a solid material for a magnet having a density exceeding 80% by volume relative to the true density of the raw magnetic powder can be obtained. If the shock wave pressure is lower than 3 GPa,
It is not always possible to obtain a solid material for a magnet having a density exceeding 80%. On the other hand, if the shock wave pressure is higher than 40 GPa, decomposition products such as the α-Fe decomposition phase are easily generated, which is not preferable. When compressing and solidifying using an underwater shock wave having a shock wave pressure of 3 to 40 GPa, a solid material for a magnet having a density exceeding 80% by volume relative to the true density of the raw material magnetic powder can be obtained with good reproducibility. The shock wave pressure is 6 to 40 GP
When the underwater shock wave of a is used, a solid material for a magnet having a density exceeding 90% can be obtained.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The R-Fe-NH-based magnetic material used in the solid material for a magnet of the present invention can be prepared by a known method (for example, US Pat. No. 5,186,766, US Pat. No. 5,164).
No. 104, Japanese Patent No. 2703281, Japanese Patent No. 270
No. 5985, Japanese Patent No. 2708568, Japanese Patent No. 2739860, Japanese Patent No. 2857476, etc.).

For example, a rare earth-iron alloy is prepared by a high frequency method, a super-quenching method, an R / D method, an HDDR method, a mechanical alloying method, a mechanical grinding method, etc., and is roughly pulverized to several tens to several hundreds μm. Later, a nitrogen-hydrogen mixed gas,
A hydrogen nitride treatment is performed in an atmosphere of an ammonia-hydrogen mixed gas or the like to perform fine pulverization, thereby preparing an R-Fe-NH-based magnetic material. Composition of magnetic material, processing method of alloy and nitriding /
Depending on the hydrogenation method, coarse grinding or fine grinding may not be required.

In the present invention, it is important that at any stage of the process, a hydrogen source such as a hydrogen gas, an ammonia gas, or a compound containing hydrogen is contacted to introduce not only nitrogen but also hydrogen. That is, the hydrogen content of the R—Fe—N—H-based magnetic material is preferably 0.01 atomic% or more. When the amount of hydrogen is less than 0.01 atomic%, an α-Fe decomposition phase and a rare earth nitride decomposition phase are often generated, which lowers the coercive force and further lowers the corrosion resistance. If the hydrogen content is 0.1 atomic% or more, it is a more preferable raw material for a solid material for a magnet.

The crystal structure of a preferred magnetic material is Th ₂ Z
A rhombohedral crystal having an n ₁₇ type crystal structure or the like or a crystal structure similar thereto, or a hexagonal crystal having a Th ₂ Ni ₁₇ , TbCu ₇ , CaZn ₅ type crystal structure or the like or a crystal structure similar thereto, and at least one of them It is necessary to include Among them, a rhombohedral crystal having a Th ₂ Zn ₁₇ type crystal structure or the like or a crystal structure similar thereto is most preferable.

The above R—Fe—N—H based magnetic material is
It is obtained as a powder having an average particle size of 0.1 to 100 μm, and is supplied as a raw material of a solid material for a magnet. When the average particle size is less than 0.1 μm, the magnetic field orientation deteriorates,
The residual magnetic flux density decreases. Conversely, if the average particle size exceeds 100 μm, the coercive force will be low and the practicality will be poor. In order to impart excellent magnetic field orientation, a more preferable range of the average particle diameter is 1 to 100 μm. Also, R-Fe-N
-H-based magnetic materials are characterized by having high magnetic anisotropy as well as high saturation magnetization and high Curie point. Therefore, when a single crystal powder can be obtained, the magnetic field can be easily oriented by an external magnetic field, and a solid material for an anisotropic magnet having high magnetic properties can be obtained.

One of the major features of the R-Fe-NH-based magnetic material is that it has relatively high oxidation resistance and hardly generates rust. Nd-Fe-B-based sintered magnets have extremely high magnetic properties and are widely used in actuators such as VCM and various motors. It is essential to perform surface treatment with nickel plating or epoxy resin coating. On the other hand, in the case of a magnet using an R—Fe—N—H-based magnetic material, the above-described surface treatment is not required or can be simplified. That is, not only is it advantageous in terms of cost, but also when used as an actuator or a motor, the gap between the stator and the rotor can be narrowed by the surface layer having low magnetism, so that there is an advantage that a large torque can be obtained for rotation and repetitive motion. , It can make the most of the magnetic force of the magnet. Therefore, for example, (BH)
_{Even when the max} value is inferior to that of the Nd-Fe-B magnet, the same performance can be exhibited. R
In the magnet containing the Fe-NH-based magnetic material,
When no surface treatment is required, the (BH) _max value is 200
If kJ / m ³ or more an excellent preferred magnet cost performance, further preferably equal to 240kJ / m ³ or more.

However, since the R—Fe—N—H magnet material is a fine powder, if there are many passages of oxygen, such as voids, which are continuous pores, the surface of the fine powder is oxidized and deteriorated, and the coercive force is reduced. It becomes a factor to do. Therefore, it is necessary to sufficiently increase the density and prevent oxygen from entering the surface. Therefore, the filling rate is required to be 95% or more, preferably 98% or more, and particularly the filling rate near the surface is required to be close to 100%.

By the way, Th ₂ Zn ₁₇ containing no hydrogen is used.
When optimizing the magnetic properties, the type R-Fe-N-based magnetic material has a nitrogen content of less than 3 per R ₂ Fe ₁₇ , and the thermodynamically unstable R ₂ Fe ₁₇ N _{3- The Δ} phase occurs. This phase is easily decomposed into α-Fe and rare earth nitride by thermal and mechanical energy, so that it cannot be a high-performance magnet solid material by conventional shock wave compression.

On the other hand, hydrogen is in the range specified above.
If controlled within, the main phase is usually thermodynamically stable
R_TwoFe₁₇N_ThreeH_xPhase or R containing excess nitrogen_TwoFe₁₇N
_{3 + Δ}H _xPhase (usually x is in the range of about 0.01 to 2)
Α-Fe and nitrided nitride by thermal and mechanical energy
Decomposition into earth is H-free Th_TwoZn₁₇Type R-Fe
It is significantly suppressed as compared with the -N-based magnetic material. this thing
Has high density, high magnetic properties, thermal stability and oxidation resistance
What is important for obtaining excellent solid materials for magnets
Absent.

As the R-Fe-NH-based magnetic material used in the present invention, various magnetic materials having different magnetization reversal mechanisms such as nucleation type, pinning type, exchange spring type and exchange coupling type are used as solid materials for magnets. be able to. All of these magnetic materials are 600
Since the decomposition reaction occurs at a temperature exceeding ℃, it cannot be made into a solid material for magnets by a sintering method that densifies at a high temperature, and it is extremely difficult to mold using the impact compression method of the present invention. It is an effective material group.

As described above, the decomposition of R-Fe-N-H-based magnetic material due to thermal and mechanical energy is remarkably suppressed as compared with the R-Fe-N-based magnetic material containing no H. If this is decomposed to form a large α-Fe decomposition phase having a particle size exceeding 100 nm and a rare earth nitride phase, despite the fact that a large amount of expensive rare earth is contained,
The α-Fe decomposition phase becomes buds of the reverse magnetic domain, and the coercive force is greatly reduced, which is not preferable.

Therefore, Fe-Ni, Fe-Co-Ni and their nitrides, such as Fe, Co, Fe-Co, and permalloy, as a sub-phase of the R-Fe-NH-based magnetic material, When a soft magnetic phase such as an alloy or a compound of the above component and the M component is contained, a practical coercive force can be obtained by adjusting the particle size or thickness of the soft magnetic phase to about 5 to 100 nm. In addition to maintaining
The amount of expensive rare earth elements can be saved, and a magnet with high cost performance can be obtained. These soft magnetic subphases have the effect of improving the residual magnetic flux density of the R-Fe-NH-based magnetic material. However, if the particle size or thickness of the soft magnetic phase is less than 5 nm, the saturation magnetization becomes small, and if it exceeds 100 nm, anisotropy due to exchange coupling between the soft magnetic phase and the hard magnetic phase and between the soft magnetic phases. Cannot be maintained, and the coercive force becomes extremely low as buds of reverse magnetic domains, which is not preferable.

In order to achieve such a microstructure, R-
As a method for producing an Fe raw material, a known method of adding an M component to obtain an R-Fe-M raw material by a rapid quenching method, a known method such as a mechanical alloying method or a mechanical grinding method, or a pulverizing method according thereto With R-Fe or R-
A method such as producing an Fe-M raw material can be employed.

At this time, the amount of the soft magnetic subphase is 5 to 5
It is preferably 0% by volume. If it is less than 5% by volume, the coercive force will be relatively high, but the residual magnetic flux density will be less than R-F
It is not so much higher than the case of the e-N-H-based material alone, and 5
If it exceeds 0% by volume, on the contrary, the residual magnetic flux density increases, but the coercive force decreases greatly, and no high (BH) _max can be obtained in any case. A more preferable range of the amount of the soft magnetic phase is 10 to 40% by volume.
It is.

Furthermore, rare earth such as Nd-Fe-B system - iron - boron Motokei magnetic material, SmCo ₅ type or Sm ₂ Co ₁₇ based rare earth such as - cobalt based magnetic material, hard magnetic such as ferrite-based magnetic material By mixing one or more of the powders with the R-Fe-NH-based magnetic material within a range of 50% by volume or less, the magnetic properties, thermal stability,
A solid material for a magnet in which various practical requirements such as cost are optimized can be obtained.

In general, the more rare-earth-iron-boron-based materials are included, the higher the overall magnetic properties are. However, the corrosion resistance is reduced and the cost is increased. The more rare-earth-cobalt-based materials are included, the higher the thermal stability. Improves, but the magnetic properties decrease,
The higher the cost, the more ferrite-based magnetic material is included, the lower the cost, the better the temperature characteristics, but the lower the magnetic characteristics. Mixing the R-Fe-N-H-based magnetic material with another magnetic material having an extremely different particle size has the advantage that the conditions for increasing the filling rate become wider.

The solid material for a magnet of the present invention, in particular, R-F is used for the purpose of producing a magnet having a high coercive force and a high squareness ratio.
A non-magnetic phase can be present at the grain boundaries of the e-N-H-based magnetic material. As the method, there are known methods such as Japanese Patent No. 27059885, for example, a method of mixing and heat-treating a magnetic powder and a non-magnetic component, a method of plating the surface of a magnetic powder, and a method of plating a surface of a magnetic powder. Examples include a method of coating a nonmagnetic component by various vapor deposition methods, and a method of treating a magnetic powder with an organic metal and photodecomposing the organic metal to coat the powder surface as a metal component.
Further, a method of mixing an R—Fe—N—H-based magnetic material and a non-magnetic component, compressing the mixture, and then compressing by a shock wave is also possible.

The non-magnetic components include Zn, In, Sn,
Each low melting point metal such as Ga having a melting point of 1000 ° C. or lower, preferably 500 ° C. or lower is preferable. In particular, when Zn is used, the coercive force is dramatically increased and the thermal stability is also improved.

The solid material for a magnet of the present invention can realize higher cost performance by being joined to and integrated with a soft magnetic solid metal material. Fe material,
The magnetic flux density can be enhanced by combining an Fe-Co material, a silicon steel sheet, etc. with a solid material for R-Fe-N-H magnets, and furthermore, those materials or materials containing Ni or Ni on the surface The workability and the corrosion resistance can be further increased by bonding together.

FIGS. 1 and 2 show an example in which a solid material for an R—Fe—N—H magnet and a soft magnetic material are joined and integrated. FIG.
An example of a cross section of a solid material for a magnet obtained by joining and integrating a R-Fe-NH-based magnetic material (hard magnetic layer) and a soft magnetic solid metal (soft magnetic layer) is shown. FIG. 2 shows R-Fe
1 shows an example of a cross section of a solid material for a magnet in which -N-H-based magnetic material layers (hard magnetic layers) and soft magnetic layers are alternately laminated and integrated. With the configuration shown in FIG. 2, cost reduction can be achieved without impairing the surface magnetic flux density of the magnet.

A major feature of the present invention is that R-Fe-N
-When the H-based magnetic material powder and the soft magnetic bulk material or powder are mixed and shock-wave compressed simultaneously without mixing, R
-Since the solidification of the Fe-NH-based magnetic material and the integration with the soft magnetic material can be performed simultaneously, there is no need to perform cutting, welding, bonding with an adhesive, etc. for integration in a later process. The cost merit is great.

As shown in FIG. 3, the solid material for a magnet of the present invention can be partially or entirely covered with a non-magnetic solid material. FIG. 3 illustrates a cross section of a solid material for a magnet covered with a nonmagnetic material. Solid magnet materials that cover the entire surface with a non-magnetic material also have the effect of increasing corrosion resistance, so in applications in harsh environments of high temperature and high humidity, non-magnetic materials are coated even if the magnetic properties are slightly sacrificed. In some cases, it is more preferable.
Examples of the non-magnetic material include an organic material, a polymer, an inorganic material, and a non-magnetic metal having a high decomposition temperature or a high melting point. Also in this case, when the R-Fe-N-H-based magnetic material powder and the non-magnetic solid material or powder are simultaneously charged without being mixed and then subjected to shock wave compression, R-Fe-N
-The solidification of the H-based magnetic material and the integration with the non-magnetic material can be performed simultaneously.

In order to make the solid material for magnet anisotropic and to make a magnet, the magnet is usually magnetized. At this time, a large impact is applied to the solid material for magnet and the solidified R-Fe-N-H
Even a solid material for a system magnet may cause cracking or chipping. For this reason, depending on the magnetic field or the magnetization method, it is preferable to cover a part or the entire surface of the magnet with a nonmagnetic solid material to obtain a solid material for magnets having high impact resistance.

FIG. 4 shows an example of a cross section of another solid material for a magnet according to the present invention. That is, by combining the R-Fe-NH-based magnetic material with the soft magnetic material and the non-magnetic material, a solid material for a magnet as shown in FIG. 4 can be formed.

The solid material for a magnet according to the present invention is characterized by having excellent magnetic properties after magnetization. When the R-Fe-NH-based material is a magnetic anisotropic material, 80 k
At a magnetic field of at least A / m, preferably at least 800 kA / m,
It is desirable to orient the magnetic powder in a magnetic field. Furthermore, it is desirable to increase the residual magnetic flux density and coercive force by magnetizing with a static magnetic field or pulse magnetic field of 1.6 MA / m or more, more preferably 2.4 MA / m or more after the shock wave compression molding. When the R-Fe-NH-based magnetic material is an isotropic material, the magnetic field orientation at the time of compression molding is unnecessary, but it is necessary to perform the magnetization as described above to sufficiently anisotropy the magnetic field. Is required.

When the solid material for a magnet is magnetized and used as a permanent magnet, various shapes are required depending on the use. The solid material for a magnet does not contain a resin binder, has a high density, and can be easily processed into an arbitrary shape by a normal processing machine by cutting and / or plastic working. In particular, cylinders with high industrial utility value,
A great feature is that it can be easily processed into a cylindrical, ring, disk or flat plate shape. The term “cutting” as used herein refers to cutting of general metal materials, and is machining with a saw, a lathe, a milling machine, a drilling machine, a grindstone, and the like. Molding. In addition, heat treatment such as annealing at a temperature lower than the decomposition temperature of the magnetic material powder can be performed to remove the strain after the cold working. Depending on the composition of the magnetic material powder, it is possible to impart or strengthen magnetic anisotropy by plastic working, and it is also possible to adjust the coercive force by combining it with heat treatment. The heat treatment can also be used for annealing various strains generated after the shock wave compression described later or adjusting the fine structure to improve various magnetic properties. Further, when the R-Fe-NH-based magnetic material contains a low melting point metal, heat treatment is performed simultaneously with or before and after compacting to strengthen the temporary bonding between the magnetic powders, and subsequent handling It can also be used for facilitating 100 ℃ as heat treatment temperature
It is selected within the range above and below the decomposition temperature.

Next, a method for producing a solid material for a magnet of the present invention,
In particular, shock wave compression which enables the realization of the solid material for magnets of the present invention will be described. As a shock compression method using an underwater shock wave, the powder is compacted at the innermost part of a double pipe, water is poured into an intermediate part, an explosive is arranged on an outer peripheral part, and the explosive is detonated. A method of introducing a shock wave into the water of the part, compressing the powder inside the powder, pressing the powder into a closed container, putting it into the water, detonating the explosive in the water, Compression method of the powder, or Japanese Patent No. 2951349 or JP-A-6-19.
No. 8496 can be selected. In either method, the following advantages of shock compression by underwater shock waves can be obtained.

In the compression-solidification step of the shock compression method of the present invention using an underwater shock wave, the ultra-high pressure shearing property and the activating action of the shock wave induce the solidifying action and the micronizing action of the powder by metallic bonding. However, it is possible to increase the coercive force together with the bulk solidification. At this time, the duration of the shock pressure itself is longer than in the case of using a conventional shock wave, but the temperature rise due to volume compression and an increase in entropy due to the nonlinear phenomenon of the shock wave disappears in a very short time (several μs or less). Decomposition and denitrification hardly occur.

There is still a residual temperature after compression using underwater shock waves. This residual temperature is the decomposition temperature (about 600 at normal pressure).
C) or more, the R-Fe-NH compound and the like also start to decompose, deteriorating the magnetic properties, which is not preferable. However, in the case of the underwater shock wave, it is very easy to keep the residual temperature lower than in the case of the conventional shock wave.

That is, the underwater shock wave has the following characteristics. (1) The pressure of the underwater shock wave is determined by the Hugonio relation between the explosive and the water, and the pressure P is roughly expressed by the following equation. P = 288 (MPa) {(ρ / ρ ₀ ) ^7.25 −1} From the above equation, when the underwater shock wave is used, the amount of increase in the pressure P with respect to the change in the density ρ of water with respect to the reference value ρ ₀ is very large. Since it is large, an ultra-high pressure can be easily obtained by adjusting the amount of the explosive, and the temperature of the magnetic material at that time can be easily maintained at a lower temperature than in the case where a conventional shock wave is used. (2) The duration of the impact pressure itself is long. (3) The temperature rise of the magnetic material due to an increase in entropy due to volume compression and a nonlinear phenomenon of a shock wave disappears in a very short time. (4) The temperature of the magnetic material is rarely kept high thereafter, and is rarely kept long. (5) The impact pressure is uniformly applied to the object to be compressed.

For the first time, due to these excellent characteristics of the underwater shock wave, the R-Fe-N-H-based material does not undergo thermal decomposition and is easily compacted at a high density. Furthermore, by performing compacting in a magnetic field, the axis of easy magnetization of the magnetic material powder can be aligned in one direction, and even if the obtained compact is solidified by impact compression solidification, the orientation is impaired. Instead, a magnetic solid material having magnetically uniaxial anisotropy can be obtained.

As described above, R-Fe-N-H is thermally stable as a magnetic powder and hardly precipitates an α-Fe decomposition phase.
By selecting a system material and solidifying it by the above-mentioned underwater shock wave compression solidification method, it is possible to produce a high-density magnet solid material for the first time. It has excellent magnetic stability, excellent oxidation resistance, and excellent thermal stability because it does not contain a resin component as a binder for magnetic powder like a bonded magnet.

The present invention will be described based on examples. still,
The degree of decomposition of the R—Fe—N—H-based magnetic material was determined based on the X-ray diffraction pattern (Cu-Kα ray) of the molded solid material for magnets, based on rhombohedral crystals including Th ₂ Zn ₁₇ type. Or the height b of the diffraction line derived from the α-Fe decomposition phase around 44 ° with respect to the height a of the strongest line in the diffraction line derived from the hexagonal crystal structure.
The ratio was determined as b / a. If this value is 0.2 or less, it can be said that the degree of decomposition is small. Preferably it is 0.1 or less. More preferably 0.05 or less, in this case,
It can be said that there is almost no decomposition. However, the above determination method is based on the case where a material having a peak near 44 °, such as an Fe soft magnetic material, is originally contained in the R-Fe-NH-based magnetic material that is a raw material of the solid material for the magnet. Not applicable. In this case, the relative ratio of b / a in the R—Fe—N—H-based magnetic material and the solid material for the magnet can be used as a measure of the presence or absence of decomposition.

[0046]

<Example 1> Sm ₂ Fe having an average particle size of 60 μm
₁₇ mother _alloy, NH ₃ partial pressure 0.35 atm, H ₂ partial pressure 0.65
After hydrogen nitriding at 465 ° C. for 7.2 ks in an atm ammonia-hydrogen mixed gas flow, annealing was performed in an argon flow for 1.8 ks, and then pulverized by a ball mill to an average particle size of about 2 μm. . This powder,
A compact was obtained by performing green compacting while orienting in a magnetic field of 1.2 MA / m. FIG. 5 is an explanatory diagram showing an example of an apparatus for performing a shock compression method using underwater shock waves. The obtained molded body was put into a copper pipe 1 and fixed to a copper plug 2 as shown in FIG. Further, the copper pipe 3 is fixed to the copper plug 2, and the gap is filled with water, a uniform gap is provided on the outer periphery, the paper cylinder 4 is arranged, and 280 is inserted into the gap.
g of ammonium nitrate-based explosive 5 was charged, the explosive was detonated from the detonating section 6, and the explosive was detonated. At this time, the impact breaking pressure was 16 GPa.

After impact compression, Sm solidified from pipe 1
_A solid material for a magnet having a composition of _8.8 Fe _75.1 N _13.2 H _2.9 was taken out, magnetized with a pulse magnetic field of 4.0 MA / m, and measured for magnetic properties. As a result, the residual magnetic flux density B _r = 1.22 T and the coercive force H _cJ = 0.75 MA / m, (BH) _max = 260 k
J / m ³ was obtained. The density was measured by the Archimedes method, and as a result, the filling rate was 99%. Furthermore, as a result of analysis by the X-ray diffraction method, the solidified solid material for the magnet hardly caused precipitation of the α-Fe decomposition phase, and Th ₂ Zn
It was confirmed to have a _17- type rhombohedral crystal structure.

The same experiment was repeated many times by adjusting the amount of explosive. When the shock wave pressure is lower than 4 GPa, the density of the obtained solid material for magnet does not necessarily exceed 80%, and when the shock wave pressure is higher than 40 GPa, it is confirmed that decomposition products such as α-Fe decomposition phase are generated. It was also found that the shock wave pressure is preferably set to 3 to 40 GPa in order to obtain a magnet solid material having a density exceeding 80% with higher reproducibility. Further, it was also confirmed that by setting the shock wave pressure to 6 to 40 GPa, a solid material for a magnet having a density exceeding 90% can be obtained with good reproducibility.

Example 2 A predetermined amount of Sm and Fe metal powder (weight ratio 16.85: 83.15) was subjected to mechanical alloying treatment for 180 ks by a vibration ball mill.
Heat treatment was performed at 600 ° C. in a vacuum for 7.2 ks. This powder contained about 30% by volume of an Fe soft magnetic material. This powder is subjected to an NH ₃ partial pressure of 0.35 atm and a H ₂ partial pressure of 0.65 a
380 ° C. in a tm ammonia-hydrogen mixed gas stream,
Hydrogen nitride treatment was performed under the conditions of 1.2 ks, and then heat treatment was performed in hydrogen at the same temperature for 300 s. Using this powder,
As in Example 1, except by the shock wave pressure and 18 GPa, to prepare a _{Sm 6.1 Fe 81. 6 N 9.2 H} 3.1 becomes magnet solid material composition.

As a result of magnetizing the solid material for a magnet with a pulse magnetic field of 4.0 MA / m and measuring the magnetic properties, the residual magnetic flux density B _r = 1.25 T, the coercive force H _cJ = 0.40 MA / m,
(BH) _max = 209 kJ / m ³ was obtained. In addition, the result of measuring the density by the Archimedes method was 7.74 g / cm.
^{Was 3} .

The X-ray diffraction diagram of this material shows that Th ₂ Zn ₁₇
Diffraction lines derived from α-Fe were also observed in addition to the crystal structure of the rhombohedral crystal, but since this material was originally a material containing an Fe soft magnetic material that was not an α-Fe decomposition phase, it was decomposed by solidification. Whether or not a phase had occurred could not be determined exactly by X-ray diffraction. In addition, according to transmission electron microscope observation, the volume fraction of the Fe soft magnetic phase was about 30%,
The crystal grain size was about 10 to 50 nm.

<Example 3> The average particle size obtained in Example 1 was about 2
μm R-Fe-NH powder and an average particle size of about 25 μm
The Sm-Co-based powder having a composition of Sm _11.5 Co _57.6 Fe _24.8 Cu _4.4 Zr _1.7 was charged into an agate mortar so as to have a volume ratio of 50:50, and wet-mixed in cyclohexane. Using this mixed powder, as in Example 1,
However, by setting the shock wave pressure to 14 GPa, R-
A solid material for an Fe-N-H based magnet was produced. As a result of magnetizing the solid material for a magnet with a pulse magnetic field of 4.0 MA / m and measuring the magnetic characteristics, the residual magnetic flux density B _r = 1.10 T, the coercive force H _cJ = 0.83 MA / m, and (BH) _max = 209k
J / m ³ .

Example 4 Using a known diethyl zinc
Average particle size with Zn metal coated on the surface by photolysis method
Preparation of Sm-Fe-Co-NH magnetic powder of about 1 μm
Then, using this powder, as in Example 1,
By setting the wave pressure to 16 GPa, Sm _8.4Fe
_64.3Co_7.1N_12.6H_3.4Zn_4.2Solids for magnets of different composition
Materials were made. This solid material for magnets was 4.0 MA / m
As a result of magnetizing with a pulse magnetic field of
Bundle density B_r= 1.27 T, coercive force H_cJ= 0.76 MA /
m, (BH)_max= 257kJ / m^ThreeMet. The density is
7.71 g / cm^ThreeMet. In addition, the solution
As a result of the analysis, the solidified magnet solid material is Th_TwoZn₁₇
It was confirmed to have a rhombohedral crystal structure.
Diffraction line of α-Fe decomposition phase at around 44 ° and Th_TwoZ
n₁₇(303) showing the crystal structure of the rhombohedral crystal
The intensity ratio b / a was 0.08.

<Embodiment 5> A known method (JP-A-8-55)
712), wherein the magnetization reversal mechanism is a pinning type and has an average particle size of 30 μm and has an average particle size of 30 μm.
The same as in Example 1 except that the shock wave pressure was set to 14 GPa,
_A solid material for a magnet having a composition of _8.5 (Fe _0.89 Co _0.11 ) _66.8 Mn _3.6 N _18.5 H _2.6 was prepared. As a result of magnetizing the solid material for a magnet with a pulse magnetic field of 4.0 MA / m and measuring the magnetic properties, the residual magnetic flux density B _r = 1.12 T and the coercive force H _cJ
= 0.37MA / m, was _{(BH) max = 125kJ / m} 3. The density determined by the volume method was 7.70 g / cm ³ . Further, the X-ray diffraction diagram of this material shows that Th ₂ Zn
_In addition to the crystal structure of the _17- type rhombohedral, diffraction lines derived from the α-Fe decomposition phase were also observed. The intensity ratio b / a between the diffraction line of the α-Fe decomposition phase and the strongest line (303) showing the crystal structure of the Th ₂ Zn _17- type rhombohedral at around 44 ° was 0.06.

Comparative Example 1 Sm ₂ F having an average particle size of 20 μm
e ₁₇ Mother alloy was subjected to nitridation at 495 ° C. for 72 ks in a N ₂ gas flow in the same manner as in Example 1, except that the shock wave pressure was set to 18 GPa to obtain Sm _9.1 Fe _77.7 N
_A solid material for a magnet having a composition of _13.2 was prepared. The solid material for a magnet magnetized in a pulse magnetic field of 4.0 MA / m results of measurement of the magnetic properties, a residual flux density B _r = 0.96T, the coercivity _{H cJ = 0.36MA / m, (} BH) max = 120k
J / m ³ was obtained. The density was measured by the Archimedes method and found to be 7.50 g / cm ³ . In the X-ray diffraction diagram of this material, diffraction lines derived from the α-Fe decomposition phase were observed in addition to the crystal structure of the Th ₂ Zn ₁₇ type rhombohedral. 44
The diffraction line of the α-Fe decomposition phase and the Th ₂ Zn ₁₇
The intensity ratio b / a with the (303) strongest line indicating the crystal structure of the rhombohedral crystal was 0.21.

<Comparative Example 2> FIG. 6 is an explanatory view showing an example of an apparatus for performing impact compression by directly using a detonation wave of an explosive.
Using this apparatus, the R having an average particle diameter of 2 μm obtained in Example 1 was used.
-Fe-N-H-based magnetic powder is put into a copper pipe 1 and fixed to a copper plug 2, a uniform gap is provided on the outer periphery,
Is disposed, and the same amount of the ammonium nitrate explosive 5 as in the embodiment is charged into the gap, and the explosive is detonated from the detonating section 6.
Detonated the explosive. After the impact compression, a solidified sample was taken out of the pipe 1 and analyzed by X-ray diffraction. As a result, it was confirmed that SmN and a large amount of α-Fe decomposition phase were formed after the impact compression. It was found that the Fe-NH compound was decomposed. At this time, the intensity ratio b / a of the diffraction lines was about 3.

[0057]

According to the present invention, a rare earth-iron-nitrogen-hydrogen based magnetic powder having a rhombohedral or hexagonal crystal structure is compacted and subjected to shock compression by an underwater shock wave to form a binder. Without the need for self-sintering,
By using a high-density magnet solid material while preventing decomposition and denitrification, a high-performance solid permanent magnet can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an example of a cross section of a solid material for a magnet obtained by joining and integrating a rare earth-iron-nitrogen-hydrogen based magnetic material and a soft magnetic solid metal.

FIG. 2 is an explanatory view showing an example of a cross section of a solid material for a magnet in which rare earth-iron-nitrogen-hydrogen based magnetic material layers and soft magnetic layers are alternately laminated and integrated.

FIG. 3 is an explanatory view showing an example of a cross section of a solid material for a magnet in which a part or the entire periphery of a layer mainly containing a rare earth-iron-nitrogen-hydrogen magnetic material is covered with a nonmagnetic solid material. .

FIG. 4 is an explanatory view showing an example of a cross section of a solid material for a magnet.

FIG. 5 is an explanatory diagram showing an example of a means for performing a shock compression method using an underwater shock wave.

FIG. 6 is an explanatory view showing an example of a means for performing a shock compression method directly using a detonation wave of an explosive used in a comparative example.

[Explanation of symbols]

 1 Copper pipe (used to hold powder) 2 Copper plug 3 Copper pipe (used to hold water) 4 Paper cylinder (used to hold explosive) 5 Explosive 6 Initiator

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01F 1/08 H01F 41/02 G 41/02 1/04 A (72) Inventor Ichiro Shibasaki Fuji City, Shizuoka Prefecture Asahi Kasei Co., Ltd., 2nd, Samejima (72) Inventor Nobuyoshi Imaoka, 2nd Asahi Kasei Co., Ltd., Fuji City, Shizuoka Prefecture (72) Inventor, Takashi Chiba 2-29-605 F-term (Reference) 4K018 AA27 CA04 KA45 5E040 AA03 AA11 AA14 CA01 HB11 5E062 CC02 CD04 CE04 CF05 CG02

Claims (21)

[Claims] 1. A solid material for a magnet containing 50 to 100% by volume of a rare earth-iron-nitrogen-hydrogen magnetic material having a rhombohedral or hexagonal crystal structure. 2. The rare earth-iron-nitrogen-hydrogen magnetic material
Has the general formula R_αFe _100-α-β-γN_βH_γAnd R
Is at least one element selected from rare earth elements including Y
Α, β, and γ are atomic percentages and 3 ≦ α ≦ 2
0, 5 ≦ β ≦ 30, 0.01 ≦ γ ≦ 10
The solid material for a magnet according to claim 1, wherein 3. The method according to claim 1, wherein 10% by atom or less of said R and / or Fe is Ni, Ti, V, Cr, Mn, Zn, Cu, Zr, N
b, Mo, Ta, W, Ru, Rh, Pd, Hf, Re,
The solid material for a magnet according to claim 1, wherein the solid material is replaced with at least one element selected from Os and Ir. 4. The method according to claim 1, wherein 10 atomic% or less of said N and / or H is replaced with at least one element selected from C, P, Si, S and Al. The solid material for a magnet according to the above. 5. A compound of the general formula R _α Fe _{100-α-β-γ-δ} N _β H
_γ M _δ , R is at least one element selected from rare earth elements including Y, and M is Li, Na, K, M
g, Ca, Sr, Ba, Ti, Zr, Hf, V, Nb,
Ta, Cr, Mo, W, Mn, Pd, Cu, Ag, Z
n, B, Al, Ga, In, C, Si, Ge, Sn, P
b, at least one element selected from Bi and / or at least one selected from oxides, fluorides, carbides, nitrides, hydrides, carbonates, sulfates, silicates, chlorides, and nitrates of R And α, β, γ, and δ are mole percentages, 3 ≦ α ≦ 20, 5 ≦ β ≦ 30, 0.01 ≦ γ ≦ 1.
2. The method according to claim 1, wherein 0, 0.1.ltoreq..delta..ltoreq.40.
The solid material for magnet according to 1. 6. The solid material for a magnet according to claim 1, wherein 50% by atom or more of the R is Sm. 7. The method of claim 1, wherein 0.01 to 50 atomic% of the Fe is Co
The solid material for a magnet according to any one of claims 1 to 6, wherein the solid material is replaced with: 8. The magnet according to claim 1, wherein the soft magnetic material containing at least one element selected from Fe, Co, and Ni is uniformly dispersed and integrated. Solid material. 9. At least one magnetic material selected from a rare earth-iron-boron magnetic material, a rare earth-cobalt magnetic material, and a ferrite magnetic material is uniformly added and mixed,
The solid material for a magnet according to any one of claims 1 to 8, wherein the solid material is integrated. 10. The solid material for a magnet according to claim 1, wherein a non-magnetic phase exists at a grain boundary of the magnetic material. 11. A solid material for a magnet, wherein the solid material for a magnet according to claim 1 and a soft magnetic solid metal material are joined and integrated. 12. The solid material for a magnet according to claim 1, further comprising a soft magnetic layer, wherein the solid material is alternately laminated and integrated with the soft magnetic layer. 13. The solid material for a magnet according to claim 1, wherein at least a part thereof is covered with a non-magnetic solid material. 14. The solid material for a magnet according to claim 1, wherein a magnetic anisotropy is provided. 15. The solid material for a magnet according to claim 1, wherein the solid material is formed into a columnar shape, a cylindrical shape, a ring shape, a disk shape, or a flat shape. 16. The solid material for a magnet according to claim 1, wherein the solid material is subjected to impact compression and solidification using an underwater shock wave. 17. The method for producing a solid material for a magnet according to claim 1, wherein the green compacting of the raw material powder is performed in a magnetic field. 18. The method according to claim 1, wherein after the raw material powder is compacted, the raw material powder is subjected to impact compression and solidification using underwater shock waves.
7. The method for producing a solid material for a magnet according to 6. 19. After the raw material powder is compacted in a magnetic field,
17. The method for producing a solid material for a magnet according to claim 16, wherein the underwater shock wave is used for impact compression and solidification. 20. The method for producing a solid material for a magnet according to claim 15, wherein the solid material is formed by cutting and / or plastic working. 21. The method for producing a solid material for a magnet according to any one of claims 1 to 16, comprising a step of heat-treating the material at least once at a temperature of 100 ° C. or higher and lower than a decomposition temperature. 17. The method according to claim 17, wherein:
0. The method for producing a solid material for a magnet according to any one of the above items.