JP2002270417A - Permanent magnet particle, its manufacturing method, and permanent magnet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide permanent magnet particles which can be formed into a permanent magnet having a large maximum energy product, its manufacturing method, and a permanent magnet made of the same. SOLUTION: Particles of hard magnetic phase and other particles of soft magnetic phase which are not compatible with each other are made 10 to 100 nm in width and 10 to 2000 nm in length respectively, and the particles of one phase cover the surfaces of the other phase for the formation of permanent magnet particles. For example, an alloy melt composed of 6 mol% Nd, 91 mol% Fe, and 3 mol% B is filled in a nozzle 21 heated with a heating coil 24 and discharged out through the nozzle tip 22 at a proper flow rate onto the surface of the rotary metal roll which rotates at a high speed for forming amorphous thin pieces 25 through a quenching method. The amorphous thin piece 25 is micronized by irradiation with a YAG laser beam in a chamber 31, and the fine particles are crystallized through a thermal treatment. The crystallized particles are formed into a bonded magnet or a sintered magnet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet for a bonded magnet or a sintered magnet having a structure in which a hard magnetic phase and a soft magnetic phase are uniformly and finely mixed, and having higher magnetic properties than conventional magnets. The present invention relates to particles for use, a method for producing the particles, and a permanent magnet using the particles for permanent magnets.

[0002]

2. Description of the Related Art The conventional Nd-Fe-B based sintered magnet has a maximum energy product of 470 kJ / m ³ , and a bonded magnet manufactured by resin bonding has a limit of 239 kJ / m ³ . In order to achieve compactness and high performance, it is desired to further increase the maximum energy product. On the other hand, an exchange spring magnet, which is a permanent magnet having a structure in which a hard magnetic phase and a soft magnetic phase are composited on a nanoscale, has been proposed, and has a theoretical energy product of 955 kJ / m.
Research and development are being actively conducted because ³ is expected, but the method of manufacturing this magnet is as follows: (1) A magnet is manufactured by precipitating a soft magnetic phase and a hard magnetic phase by heat treatment of an amorphous ribbon. (2) A thin film method for producing a magnet by arranging a soft magnetic phase and a hard magnetic phase in layers by vapor deposition or the like (for example, JP-A-9-237714, JP-A-11-127) (No. 214219) (3) A method of diffusing a rare earth element or a B element into the surface layer of acicular iron powder to produce (for example, JP-A-7-106110,
JP-A-8-203715, JP-A-8-335507
No.) has been proposed.

[0003]

However, these conventional methods for manufacturing a replacement spring magnet have the following problems. (1) In the quenching method, a magnet is manufactured by precipitating a soft magnetic phase and a hard magnetic phase by heat treatment of an amorphous ribbon, but the size of the hard magnetic phase and the soft magnetic phase after the heat treatment is large due to the large ribbon dimensions. The exchange spring effect became insufficient due to unevenness in the order of nm to μm, and the dimensions showing the exchange spring effect were unclear. As a result, there was a problem that desired magnetic characteristics could not be obtained and anisotropic conversion was not possible. Therefore, the magnetic flux density and coercive force were low, the maximum energy product as a sintered magnet did not increase from about 470 kJ / m ³ , and the maximum energy product as a bond magnet was less than 239 kJ / m ³ .

(2) In the thin film method, nm
Magnets are manufactured by arranging a soft magnetic phase and a hard magnetic phase in the order of a layer, but the shape is limited, and it is not possible to manufacture magnet powder or bulk-shaped magnets for use in bonded magnets. It was difficult to manufacture bulk magnets such as magnets. (3) When manufacturing by diffusing a rare earth element or B element into the surface layer of acicular iron powder, a magnet having stable magnetic properties could not be obtained. In other words, in the method of forming a hard phase on the surface by diffusion after coating with a soft magnetic phase, the thickness of the hard phase is not constant, and the hard phase cannot be uniformly dispersed, so that the hard phase cannot be formed, making it difficult to put into practical use. It is.

The present invention solves these problems, and provides permanent magnet particles having a large maximum energy product, having stable magnetic properties, and capable of obtaining a permanent magnet excellent in productivity and workability. A method and a permanent magnet comprising the permanent magnet particles are provided.

[0006]

For this reason, the permanent magnet particles are composed of a structure in which a hard magnetic phase and a soft magnetic phase are composited on a nanoscale. The width of each phase is 10 to 100 n
m, the length is 10 to 2000 nm, and one is composed of one or a plurality of particles having a configuration in which one surface covers the other surface. As the hard magnetic phase, an alloy having a composition of R—Fe—B (R is at least one of rare earth elements including Y) or R—Fe—N (R is at least one of rare earth elements) Alloy) or an Fe-M (M is at least one of transition metals such as Co, Ni, Mn) alloy, and Fe or Fe-M-N (M is Co , Ni, Mn, at least one of transition metals) or Fe-
It is desirable to use an alloy having an N composition.

Further, in order to produce such particles for permanent magnets, a molten alloy having a composition containing Fe in excess of the composition ratio of the intermetallic compound phase of R 2 Fe 14 B (R is at least one of rare earth elements) is quenched. After making the amorphous state by laser ablation, the amorphous state is 20 to 200 nm in width and 10 to 2000 nm in length.
Of fine particles of R ₂ F
The e ₁₄ B intermetallic compound phase and the Fe phase are crystallized. In addition,
R ₂ Fe ₁₄ B (R is at least one of rare earth elements) Fe is in excess of the composition ratio of the intermetallic compound phase, and has a width of 20 to 200 nm and a length of 10 to 2000 nm according to the ultrafine particle manufacturing method. And then heat-treating the fine particles to crystallize the R ₂ Fe ₁₄ B intermetallic compound phase and the Fe phase. Note that the heat treatment is preferably performed in a magnetic field.

As another method, R-Fe-B (R is at least one kind of rare earth element including Y) or R-Fe-N (R is at least one kind of rare earth element) by laser ablation. Having a hard magnetic phase consisting of 10 to 100 nm in width and 10 to 2000 n in length
m fine particles are prepared, and the fine particles are coated with FeO (OH) in an alkaline solution containing Fe (OH) ₂ colloid and reduced to form a soft magnetic phase coating having a thickness of 10 to 100 nm.

Further, using laser ablation,
Fe or Fe-M (M is at least one of transition metals such as Co, Ni and Mn), an alloy having an Fe-N composition, or Fe-M-N (M is Co, Ni,
Fine particles having a width of 10 to 100 nm and a length of 10 to 2000 nm having a soft magnetic phase made of an alloy having an Fe—N composition are prepared. R is at least one of the rare earth elements containing Y), and coated and reduced in a hydrolyzable metal compound solution containing Fe and B to form a hard magnetic phase film having a thickness of 10 to 100 nm.

Incidentally, by using laser ablation, one of the hard magnetic phase and the soft magnetic phase is
The particles are prepared into fine particles having a thickness of 10 to 2000 nm and the other magnetic phase is subjected to a surface treatment of 10 to 100 nm in thickness by laser ablation on the surface of the fine particles to prepare particles for permanent magnets.

Further, a seed crystal of FeO (OH) is grown in an aqueous ferrous salt solution having a pH of 4.5 or less and reduced in a reducing gas to obtain a width of 10 to 100 nm and a length of 10 to 100 nm.
Fine particles having a soft magnetic phase of 2000 nm are prepared, and the fine particles are coated with a hydrolyzable metal compound solution containing R (R is at least one of rare earth elements including Y), Fe, and B, and reduced. By doing, the thickness is 10
A coating of ~ 100 nm hard magnetic phase is formed. In addition, the fine particles have a thickness of 1 by laser ablation.
A coating of a hard magnetic phase of 0 to 100 nm may be formed.

As still another method, a metal layer of a hard magnetic phase that does not dissolve in the soft magnetic metal is formed on the surface of metal particles having a soft magnetic phase by a sputtering method. Phase width 10 ~ 100nm, length 10 ~ 10
Fine particles having a size of 2000 nm are formed.

As another method, Fe or Fe-
M (M is at least one of transition metals such as Co, Ni and Mn) or a soft magnetic phase metal having an Fe—N composition is formed into a ribbon having a thickness of 10,000 nm or less by a quenching method. The surface is coated with a hard magnetic phase in a solution of a hydrolyzable metal compound containing R (R is at least one of rare earth elements containing Y), Fe and B, reduced, and heat-treated at 1000 ° C. or less. This orients the crystals and pulverizes them to form particles for permanent magnets.

Further, Fe or Fe-M (M is Co,
At least one of transition metals such as Ni and Mn)
Or an alloy having a soft magnetic composition having an Fe—N composition;
Any one of alloys having a hard magnetic composition having a composition of -Fe-B (B is at least one of rare earth elements including Y) is formed into a ribbon having a thickness of 10,000 nm or less by a quenching method, and the surface thereof is formed. Next, a coating of the other alloy is formed by a surface treatment, and this is subjected to a heat treatment to orient the crystals, which are pulverized.

The particles for permanent magnets are bonded with an epoxy resin, a nylon resin or an acrylic resin, a magnetic field is formed, and the magnetic field is cured to produce a bonded magnet. The permanent magnet particles are sintered at a temperature of 1000 ° C. or lower, and a magnetic field is formed to obtain a sintered magnet.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiment shown in the drawings will be described below. FIG. 1 is a block diagram of an embodiment showing particles for permanent magnets and a step of forming a permanent magnet from the particles.
Is an alloy melt, 2 is a process for producing amorphous flakes by a quenching method, 3 is a micronization process, and 4 is a crystallization process by heat treatment. Reference numeral 5 denotes a resin mixing step for manufacturing a permanent magnet, 6 denotes a magnetic field forming step, 7 denotes a hardening and curing step, and 8 denotes a solidified magnetic field forming step. FIG. 2 is a schematic diagram showing an apparatus for producing an amorphous flake, in which 21 is a nozzle, 22 is a nozzle port, 23 is a rotating metal roll, 24 is a heating coil, and 25 is an amorphous flake. FIG. 3 is a schematic view showing an apparatus for laser ablation as an embodiment for atomizing amorphous flakes.
Is a generation chamber, 32 is a target, 33 is a target holder, 34 is a magnet, 35 is a YAG laser, 36 is an exhaust port, 37 is a carrier gas inlet for introducing an inert gas such as He into the generation chamber 31, and 38 is a low pressure. An operation electric mobility classifier, 39 is a He sheath gas inlet, 40 is a deposition chamber, 41 is a deposition substrate, and 42 is a carrier gas outlet.

For example, Nd 6 mol%, Fe 91 mo
An alloy melt 1 having a composition of 1% and 3 mol% of B is injected into a nozzle 21 and heated by a heating coil 24 so as not to be solidified in the nozzle 21, and an appropriate amount is placed on a rotating metal roll 23 rotating at a high speed from a nozzle port 22. Let them be discharged one by one. The alloy melt that has fallen on the surface of the rotating metal roll 23 is rapidly cooled to become amorphous flakes 25. The amorphous thin piece 25 is set as a target 32 on a target holder 33 in the generation chamber 31 and fixed by suction with a magnet 34 attached to the back of the target holder 33. Generation chamber 31
The YAG laser 35 is irradiated on the amorphous thin target 32 by adjusting the internal pressure to 2.7 kPa, the applied voltage of the low-pressure operation electric mobility classifier 38 to 15.0 V, and the pressure in the deposition chamber 40 to 2.5 kPa. Then, the amorphous flakes are turned into fine particles, and the low-pressure operation electric mobility classifier 38 is used.
And is classified and deposited on the deposition substrate 41 in the deposition chamber 40. The thus obtained width of 20 nm and length of 100
When an amorphous alloy powder having a thickness of nm is heated to 500 ° C. in a heat treatment furnace (not shown) while applying a magnetic field, the amorphous alloy powder crystallizes into a state in which the Nd ₂ Fe ₁₄ B phase and the Fe phase are mixed.

The bonded magnet is formed from the crystallized particles taken out of the heat treatment furnace through the steps of resin mixing 5, magnetic field forming 6, and curing 7. In addition, a sintered magnet is formed from the crystallized particles through the step of solidifying magnetic field forming 8.

FIG. 4 is a schematic view showing another embodiment for forming fine particles, 50 is a raw material alloy, 51 is a processing chamber, 52 is a crucible, 53 is a heating coil, 54 is a carrier gas inlet,
Reference numeral 5 denotes an ultra fine particle collecting tube, and reference numeral 56 denotes a cooling adhesion plate. Nd4
The raw material alloy 50 having a composition of mol%, 94 mol% of Fe, and 2 mol% of B is charged into the crucible 52, the inside of the processing chamber 51 is evacuated by an exhaust device (not shown), and He gas is introduced from the carrier gas inlet 54. The raw material alloy 50 in the crucible 52 is maintained at a predetermined gas pressure by the heating coil 53.
Dissolve. The melted raw material alloy 50 evaporates and is cooled by the convective inert gas, enters the ultrafine particle collecting tube 55, and adheres to the cooling adhesion plate 56. The amorphous ultrafine particles thus obtained are collected and heated to 500 ° C. while applying a magnetic field in a heat treatment furnace, whereby the Nd ₂ Fe ₁₄ B phase and the F
It crystallizes into a state in which the e phase is mixed. A bonded magnet or a sintered magnet is made from the crystallized fine particles taken out of the heat treatment furnace.

In the embodiment shown in FIG. 4, a method using a gas evaporation method is shown as a method for obtaining nano-order amorphous fine particles, but a chemical method such as a coprecipitation method, a sol-gel method, or the like, An ultrafine particle manufacturing method such as a physical method such as a cluster beam deposition method or a mechanical method such as mechanical alloying may be used.

FIG. 5 is a block diagram showing another manufacturing process, in which 11 is an alloying process, 12 is a laser pyrolysis process,
3 is a surface treatment step, 14 is a reduction step, 5 is a resin mixing step for manufacturing a bonded magnet, 6 is a magnetic field forming step, 7 is a hardening and hardening step, and 8 is a solidification magnetic field forming step for manufacturing a sintered magnet. FIG. 6 is a schematic view showing the structure of magnetic fine particles in each step, 61 is a powder of a hard magnetic phase, 62 is fine particles subjected to surface treatment, 63 is reduced fine particles, and 64 is magnetic field molding or solidification magnetic field molding. Hardened, 65
Indicates the state of the particles in the permanent magnet structure. In the alloying step 11, an alloy having a composition of R—Fe—B (R is at least one of rare earth elements) is prepared. In the laser pyrolysis step 12, the width is 10 to 100 nm and the length is 10 to 100 nm by a laser ablation apparatus. 10 to 2000n
m fine powder. The laser ablation device is shown in FIG.

If the fine particles have a width of 10 nm or less, it is difficult to manufacture them by laser ablation.
When the length is larger than 00 nm, the magnetic flux density is reduced, and the exchange spring effect cannot be obtained. When the length is shorter than 10 nm, the same manufacturing as the width cannot be performed. I do. This fine powder is subjected to M (Fe, Co, N
i, at least one of transition metals such as Mn)
In an alkaline solution containing M (OH) ₂ colloid having a composition, MO (OH) is coated and reduced in a reduction step 14. If the thickness of the coating is more than 100 nm, the coercive force is reduced.

Further, an alloy having an Fe—B composition is prepared, and the width of the alloy is 10 to 10 in an apparatus such as laser ablation.
A fine powder having a length of 100 nm and a length of 10 to 2000 nm is formed into a fine powder having a composition of 100 nm or less in a hydrolyzable metal compound solution having a composition of R—Fe—B (R is at least one of rare earth elements). By performing coating with a thickness and further reducing the thickness, magnetic fine particles having a hard magnetic phase and a soft magnetic phase can be produced. Also, Fe-B
(R is at least one kind of rare earth element) and R-Fe-B (R is at least one kind of rare earth element) are alloyed in a device such as laser ablation to form a hard magnetic phase. And a magnetic powder having a soft magnetic phase, having a width of 10 to 100 nm and a length of 10 to 2000 n
m particles. This fine powder is formed into a coating having a thickness of 100 nm or less in a thermally hydrolyzable metal compound solution, and reduced to produce magnetic fine particles for a permanent magnet having a hard magnetic phase and a soft magnetic phase. can do.

In still another embodiment, the Fe-B composition
After preparing an alloy having a composition of R-Fe-B (R is at least one of rare earth elements), the width is 10 to 100 nm and the length is 10 to 200 by laser ablation.
Make fine powder of 0 nm. This fine powder is converted to Fe (OH) ₂
A hard-solid magnetic phase and a soft-magnetic phase having a thickness of 100 nm or less are subjected to a surface treatment of FeO (OH) in an alkali solution containing a colloid, and the surface treatment is reduced with hydrogen gas. Magnetic fine particles can be obtained.

In a ferrous salt aqueous solution, FeO (OH)
The same magnetic fine powder can be obtained without using a device such as laser ablation by growing a seed crystal and producing fine powder having a size of 100 nm or less and reducing it with hydrogen gas. The pH of the aqueous ferrous salt solution
If the pH is 4 or more, a seed crystal of FeO (OH) cannot be obtained, so the pH is set to 4 or less.

A method of preparing from a weakly alkaline aqueous solution containing a FeCO ₃ colloid having a pH of 8 to 10 by an oxidation reaction of FeCO ₃ , and a method of oxidizing Fe (OH) ₂ from a strongly alkaline aqueous solution containing a FeCO ₃ colloid having a pH of 11 or more Can produce the same FeO (OH) particles.

A magnetic fine powder made of an alloy having an Fe-N composition as a soft magnetic phase and an alloy having an R-Fe-N (R is at least one of rare earth elements) composition in a hard magnetic phase is also used. It can be prepared in the same manner as in the case where Fe-B and R-Fe-B are used.

FIG. 7 is a block diagram showing a manufacturing process by a sputtering method, wherein 15 is a soft magnetic particle, 16 is a coating process by sputtering, 5 is a resin mixing process, 6 is a magnetic field forming process, and 7 is a magnetic field forming process.
Denotes a curing step, and 8 denotes a solidification magnetic field forming step. FIG. 8 is an embodiment showing an apparatus of the coating step 16 by the sputtering method.
1 is a rotary barrel, 72 is a target, 73 is a power supply for applying a voltage to the target, 74 is a motor for rotating the barrel 71, 75 is an exhaust device, 76 is a gas cylinder, and 77 is soft magnetic particles. FeO (OH) needle-shaped crystals reduced in a rotary rotary furnace with a width of 100 nm and a length of 2000 n
m soft magnetic particles 77 having a width of 10 to 100 nm and a length of 10 to 2000 nm, which are obtained by pulverizing needle-shaped Fe particles of m.
1 and the inside of the rotary barrel 71 is 1 × 10
⁼ Exhaust to ³ Pa or less. While rotating the rotary barrel 71 with the motor 74, argon gas was introduced from the gas cylinder 76 and adjusted to about 1 Pa, and the hard magnetic phase Nd-D
A power source 73 is connected to a target 72 having a y-Fe-B alloy.
From -300 V is applied to perform sputtering.

FIG. 9 shows another embodiment, in which soft magnetic particles 77 are put in a vacuum chamber 78, evacuated by an exhaust device 75, and argon gas is introduced. I'm trying to do it. FIG. 10 shows still another embodiment, in which 72 is a target, 73 is a power source, 75 is an exhaust device, 76 is a gas cylinder, 77 is a soft magnetic particle, 77 is a vibration device, 81 is a vacuum tank, 82 is a supply device, 83 is a collector,
84 is a belt conveyor, 85 is a permanent magnet, and 86 is a heater. The soft magnetic Fe particles 77 are put in the supply device 82, and the gas in the vacuum chamber 81 is exhausted by the exhaust device 75 and argon gas is introduced as in the embodiment of FIG. Belt conveyor 84
Is moved in the direction of the arrow by a motor (not shown), and a voltage is applied from the power supply 73 to vibrate the supply device 82 by the vibration device 79. The soft magnetic particles 77 jumped up by the vibration are attracted by the permanent magnet 85 and adhere to the surface of the belt conveyor 84, and move with the belt conveyor, face the target 72, and are sputtered by the Nd-F of the hard magnetic phase by sputtering.
The e-B alloy is coated, and the attracting force of the permanent magnet 85 is weakened on the collecting device 83 to be dropped and collected in the collecting device 83.

The soft magnetic particles 77 attracted by the permanent magnet 85 and conveyed by the belt conveyor 84 increase in the thickness of the hard magnetic coating as the sputtering time increases, and are magnetized by the permanent magnet 85 to be collected by the collector 83. It is difficult to fall.
In this case, a heater 86 is provided at a position facing the upper part of the collecting device 83, and Nd-Fe-B adhered to the belt conveyor is provided.
The alloy is thermally demagnetized to reduce the attractive force, and is reliably dropped on the collector 83.

FIG. 11 is a block diagram of a further different manufacturing method, in which one of the ribbons of the hard magnetic phase and the soft magnetic phase is subjected to surface treatment with the other, and then pulverized after heat treatment. Step 18, coating step of soft magnetic phase, 1
9 is a heat treatment step, and 20 is a pulverization step. FIG. 12 shows FIG.
FIG. 13 shows the crystal structure of the magnet powder in each step of FIG. Fe or Fe-M
(M is at least one of transition metals such as Co, Ni, and Mn) or a soft magnetic phase metal having a Fe—N or Fe—B composition is prepared, and the quenched metal roll shown in FIG. A thin band 91 having a thickness of 10000 nm or less is formed. This ribbon 91 is coated with a coating of Nd—Fe—B in a hydrolyzable metal compound solution containing R—Fe—B (R is at least one of rare earth elements including Y). 92 is reduced, heat-treated at 700 ° C., and the crystal magnetic anisotropy of the ribbon 93 in which Nd is diffused in Fe is oriented in the direction of arrow 95. Created. Hard magnetic phase 96 and soft magnetic phase 97
(The hard magnetic phase 96 in the figure) has a width W of 10 to 10.
0 nm and the length L is 10 to 2000 nm.

Further, Fe—B or R—Fe—B (R
Is an alloy having a composition of at least one of the rare earth elements) is formed into a ribbon with a quenched metal roll, and Fe—B or R—Fe—B (R is at least one of the rare earth elements)
12) is coated using a device such as laser ablation as shown in FIG. 12 and further subjected to reduction and heat treatment to form an anisotropic magnet powder 94 having a hard magnetic phase and a soft magnetic phase. can get. It should be noted that, instead of a device such as laser ablation, a sputtering device, vapor deposition, CV
Similar effects can be obtained by D, plasma CVD, and ion plating.

The above manufacturing method is also applicable to magnet particles comprising a soft magnetic phase having an Fe—N composition and a hard magnetic phase having an R—Fe—B (R is at least one of rare earth elements) composition. it can. The alloy is formed into a ribbon by a quenched metal roll, and a ribbon having Fe—B or R—Fe—B (R is at least one of rare earth elements) is formed by using a device such as laser ablation at 92 in FIG. And further subjected to reduction and heat treatment to obtain anisotropic magnet powder 94 having a hard magnetic phase and a soft magnetic phase.

A 5000 nm-thick ribbon of Nd—Fe—B was prepared, and FeO (OH) ₂ was oxidized with an alkaline aqueous solution containing Fe (OH) ₂ colloid to form FeO (OH) 2.
Is reduced in hydrogen at 400 ° C., and the Nd—Fe—B ribbon coated with Fe is heat-treated at 700 ° C. and pulverized. Further, the soft magnetic ribbon of Fe-B is formed by Nd (O
H) Surface treatment of NdO is performed in a hydrolyzable metal compound solution having the composition of ₂ and reduced in hydrogen gas, heat-treated and pulverized. The Nd-Fe-B ribbon may be subjected to a surface treatment of Fe-B by laser ablation or sputtering, and the Fe-B soft magnetic ribbon may be subjected to a surface treatment of Nd.

[0035]

EXAMPLE Four bonded magnets (samples 1 to 4) and sintered magnets (samples 5 to 8) were prepared in accordance with the embodiments shown in FIGS. 1 to 3, and the maximum energy product was measured for the samples. The results obtained are shown in Table 1.

[Table 1] Both the bonded magnet and the sintered magnet have a higher maximum energy product than the conventional magnet. The width or length of each phase of the hard magnetic phase and the soft magnetic phase of the permanent magnet particles is 1
If it is less than 0 nm, the coercive force will be reduced by averaging the anisotropy. When the width of each phase exceeds 100 nm, the exchange interaction between the phases becomes weak and the coercive force decreases, and when the length of each phase exceeds 2000 nm, the coercive force decreases due to the formation of domain walls.

Further, a mixture of 20 bonded magnets according to this embodiment and, as a conventional example, Nd powder, B powder, and needle-shaped iron powder were reduced in a reducing gas atmosphere containing hydrogen, and reduced in an inert gas. Table 2 shows the results of comparing 20 bonded magnets made of the heat-treated powder.

[Table 2] Thus, the permanent magnet of the present invention is
The variation in characteristics is extremely small.

A sample according to the embodiment of FIG. 5 was prepared by a laser ablation method in which the pressure in the production chamber was 2.7 kPa, the voltage applied to the low-pressure operation electric mobility classifier was 15.0 V, and the pressure in the deposition chamber was 2.5 kPa. The following samples were produced using the particles for permanent magnets. (Sample 11) Nd-F having a width of 20 nm and a length of 100 nm
e-B hard magnetic powder was prepared and subjected to surface treatment of FeO (OH) in an alkaline solution containing Fe (OH) ₂ colloid, and reduced in hydrogen gas to use Fe-treated fine particles. , Sintered magnets manufactured by solidification molding. (Sample 12) Fe-B having a width of 20 nm and a length of 100 nm
Soft magnetic powder is subjected to a surface treatment of NdO in a hydrolyzable metal compound solution having a composition of Nd (OH) ₂ , and 500 ° C. ×
A sintered magnet sintered for 10 minutes. (Sample 13) Nd-F having a width of 20 nm and a length of 100 nm
A sintered magnet manufactured by solidification molding using eB hard magnetic powder and 20 nm Fe-B powder. (Sample 14) Nd-F having a width of 20 nm and a length of 100 nm
e-B hard magnetic powder is oxidized by Fe (OH) _{2 in} an alkaline solution containing Fe (OH) ₂ colloid to form Fe (OH) _2.
A sintered magnet manufactured by solidification molding using fine particles that have been surface-treated with O (OH), reduced in hydrogen at 400 ° C., and surface-treated with Fe. (Sample 15) A sintered magnet having a width of 20 nm and a length of 100 nm, manufactured by solidification molding using Nd powder, B powder, and Fe powder.

(Sample 16) Width 20 nm, length 100 nm
The hard magnetic powder of Nd-Fe-B was subjected to a surface treatment of FeO (OH) in an alkaline solution containing a Fe (OH) ₂ colloid, and reduced with hydrogen at 400 ° C. to obtain an epoxy-based material. Bonded magnet made by adding a cured resin. (Sample 17) Fe-B having a width of 20 nm and a length of 100 nm
Was prepared by subjecting NdO to surface treatment in a hydrolyzable metal compound solution having a composition of NdO (OH) and adding an epoxy resin to the fine particles whose surface was reduced in hydrogen gas. Bond magnet. (Sample 18) Nd-F having a width of 20 nm and a length of 100 nm
A bonded magnet manufactured by using particles obtained by sintering hard magnetic powder of eB and soft magnetic powder of Fe-B powder by a solidification molding method and adding an epoxy resin thereto. (Sample 19) Nd-F having a width of 20 nm and a length of 100 nm
e-B hard magnetic powder is subjected to a surface treatment of FeO (OH) _{2 in} an alkaline solution containing a Fe (OH) ₂ colloid,
A bonded magnet manufactured by adding an epoxy-based cured resin to fine particles coated with Fe after being reduced in hydrogen at 400 ° C.

(Sample 20) Width 20 nm, length 100 nm
A bonded magnet manufactured by mixing Nd powder, Fe powder and B powder, sintering by solidification molding method, and adding an epoxy-based cured resin. (Sample 21) Sm-F having a width of 20 nm and a length of 100 nm
The hard magnetic powder of (e) is subjected to a surface treatment of FeO (OH) by an oxidation reaction in an alkaline aqueous solution containing Fe (OH) ₂ colloid, and reduced in 400 ° C. hydrogen to give Fe-coated fine particles with NH. ₃ and using the powder obtained by nitriding a mixed gas of H _2, epoxy bond magnet manufactured by adding a curing resin. (Sample 22) In an aqueous ferrous salt solution having a pH of 4.5 or less, F
A seed crystal of eO (OH) is grown to produce a fine powder, which is reduced with hydrogen gas to obtain a 20 nm wide, 100 nm long Fe.
-B soft magnetic powder is prepared, NdO is surface-treated in a hydrolyzable metal compound solution having a composition of NdO (OH), and an epoxy resin is added to the powder whose surface is reduced with hydrogen gas. The manufactured bonded magnet. Was produced.

As (Comparative Example 1), a width of 20 nm
A soft magnetic powder of Fe-B having a length of 100 nm was mixed with Nd (O
H) In a hydrolyzable metal compound solution having a composition of ₂
Surface treatment of NdO was performed, and sintered magnets were manufactured by solidification molding at 500 ° C. for 10 minutes using fine particles reduced in hydrogen gas. As Comparative Example 2, a bonded magnet in which an amorphous ribbon was precipitated in a soft magnetic phase and a hard magnetic phase by heat treatment by a quenching method and bonded with an epoxy resin was manufactured. As a (conventional example), a sintered magnet was manufactured by arranging a soft magnetic phase and a hard magnetic phase in layers by a vapor deposition method. As shown in Table 3, the magnetic properties of Samples 11 to 22, Comparative Examples 1 and 2, and a conventional example are as follows.
It is apparent that a larger maximum energy product is obtained as compared with the conventional example and the comparative example, and the characteristics are small and stable.

[Table 3]

The heat treatment temperature is 1000 ° C. in each case.
If it becomes larger, the crystal grains become coarse and the magnetic flux density and the coercive force decrease, so that the maximum energy product decreases. Figure 1
Table 4 shows the effect of the heat treatment temperature and treatment time on the crystal grain size in Table 1 and the magnetic properties obtained at that time. Table 4 shows the relationship between the temperatures, and Table 5 shows the relationship with the treatment time.

[Table 4]

[Table 5] From these results, it is desirable that the heat treatment is performed at a temperature of 1000 ° C. or less and within 5 hours.

[0042]

As described above, the permanent magnet particles of the present invention have a structure in which a hard magnetic phase and a soft magnetic phase are composited on a nanoscale, and the hard magnetic phase and the soft magnetic phase that do not form a solid solution with each other. , Each phase has a width of 10 to 100 nm and a length of 10 to 2000 nm, and is made up of one or more sets of particles. Thus, the size of the soft magnetic phase becomes the optimum size exhibiting the exchange spring effect, and a permanent magnet having a larger maximum energy product than the conventional one and having magnetic characteristics with small variations can be obtained.

Further, the hard magnetic phase is an alloy having a composition of R—Fe—B (R is at least one of rare earth elements including Y), and the soft magnetic phase is Fe or Fe—M (M
Represents at least one of transition metals such as Co, Ni and Mn.
Or more) or an alloy having an Fe—N composition to form particles for permanent magnets, and the permanent magnets made from these particles can improve the temperature characteristics and the saturation magnetic flux density. According to the manufacturing method of the present invention, the dimensions of the hard magnetic phase and the soft magnetic phase do not become larger than the nano-order even after the heat treatment, exhibit an optimal exchange spring effect, and are heat-treated in a magnetic field. There is an effect that the magnetic anisotropy is aligned in the longitudinal direction and the anisotropy becomes higher.

Further, by combining the permanent magnet particles with an epoxy resin, a nylon resin, or an acrylic resin, the magnetic properties are stabilized, the productivity of the magnet is improved, and the shape of the magnet is not restricted and the range of application is widened. In addition, by setting the sintering temperature to 1000 ° C. or less,
The nano-scale composite structure is solidified without coarsening, and a permanent magnet having a large maximum energy product can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing steps in an embodiment of the present invention.

FIG. 2 is a schematic view of an embodiment for producing an amorphous flake by a quenching method.

FIG. 3 is a schematic view showing a laser ablation apparatus.

FIG. 4 is a schematic view showing another embodiment of a fine particle forming apparatus.

FIG. 5 is a block diagram showing steps in another embodiment of the present invention.

FIG. 6 is a schematic view showing the structure of magnetic fine particles in each step.

FIG. 7 is a block diagram showing steps in still another embodiment.

FIG. 8 is a schematic view showing an apparatus in a coating step by a sputtering method.

FIG. 9 is a schematic view showing another sputtering apparatus.

FIG. 10 is a schematic view showing still another sputtering apparatus.

FIG. 11 is a block diagram of a different manufacturing method.

FIG. 12 is a view showing a crystal structure in each step of FIG. 11;

FIG. 13 is a schematic diagram showing crystal grains of the magnet powder in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Molten alloy 2 Manufacturing process of amorphous flakes by a quenching method 3 Micronization process 4 Crystallization process by heat treatment 5 Resin mixing process 6 Magnetic field forming process 7 Hardening process 8 Solidification magnetic field forming process 11 Alloying process 12 Laser pyrolysis process 13 Surface treatment Step 14 Reduction step 16 Coating step by sputtering 17 Thin strip forming step 18 Coating step 19 Heat treatment step 20 Crushing step 21 Nozzle 23 Rotating metal roll 24 Heating coil 25 Amorphous flake 31 Generation chamber 32 Target 35 YAG laser 38 Low pressure operation electric mobility classification Apparatus 40 Deposition chamber 51 Processing chamber 52 Crucible 55 Ultra fine particle collecting tube 71 Rotating barrel 72 Target 77 Soft magnetic particles 78 Vacuum tank 79 Vibration device 81 Vacuum tank 82 Supplier 83 Recoverer 85 Permanent magnet 86 Heater

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Mitsuaki Ikeda 2-1 Kurosaki Castle Stone, Yawatanishi-ku, Kitakyushu City, Fukuoka Prefecture Inside Yaskawa Electric Co., Ltd. (72) Ryuichi Oguro 2-1 Kurosaki Castle Stone, Yawatanishi-ku, Kitakyushu City, Fukuoka Prefecture Yaskawa Electric Co., Ltd. AA04 AC05 CA01 HB11 HB17 NN06 5E062 CC05 CD06 CG03

Claims (22)

[Claims] In a permanent magnet particle having a structure in which a hard magnetic phase and a soft magnetic phase are composited on a nanoscale, the width of each of the hard magnetic phase and the soft magnetic phase that do not form a solid solution with each other is 10 to 10. Particles for permanent magnets, comprising one or more sets of particles having a configuration of 100 nm and a length of 10 to 2000 nm. 2. In permanent magnet particles comprising a structure in which a hard magnetic phase and a soft magnetic phase are composited on a nanoscale, the width of each of the hard magnetic phase and the soft magnetic phase that do not form a solid solution with each other is 10 to 10. 100. A permanent magnet particle having a length of 10 to 2000 nm and a length of 10 to 2000 nm, and one or a plurality of sets of particles each of which covers the other surface. 3. The hard magnetic phase is an alloy having a composition of R—Fe—B (R is at least one of rare earth elements including Y), and the soft magnetic phase is Fe or Fe—M (M is C
The permanent magnet particles according to claim 1, wherein the particles are at least one of transition metals such as o, Ni, and Mn) or an alloy having a Fe—N composition. 4. The hard magnetic phase is an alloy having a composition of R—Fe—N (R is at least one of rare earth elements), and the soft magnetic phase is Fe or Fe—M—N (M is Co, N
3. An alloy having at least one of transition metals such as i and Mn) or an alloy having an Fe--N composition.
The particles for permanent magnets described in 1. 5. The composition ratio of R—Fe—B (R is at least one of rare earth elements) intermetallic compound phase,
e is quenched into an amorphous state by quenching the molten metal having an excessive composition, and then the width is adjusted to 20 to 20 by an ultrafine particle manufacturing method.
A method for producing particles for permanent magnets, comprising: forming fine particles having a thickness of 0 nm and a length of 10 to 2000 nm, and crystallizing the fine particles by heat treatment to form an R-Fe-B intermetallic compound phase and an Fe phase. 6. The composition ratio of an intermetallic compound phase of R ₂ Fe ₁₄ B (R is at least one of rare earth elements)
Is quenched into an amorphous state by quenching the alloy melt having an excessive composition, and then the amorphous is subjected to laser ablation to have a width of 20 to 200 nm and a length of 10 to 2000 n.
m, and further heat-treating these fine particles into R-
A method for producing particles for permanent magnets, wherein the Fe-B intermetallic compound phase and the Fe phase are crystallized. 7. The method for producing permanent magnet particles according to claim 5, wherein the heat treatment is performed in a magnetic field. 8. RF-RF by laser ablation
An alloy having a composition of eB (R is at least one of rare earth elements including Y) or R-Fe-N (R is at least one of rare earth elements) has a width of 10 to 10 having a hard magnetic phase. Fine particles of 100 nm in length and 10 to 2000 nm in length are prepared, and the fine particles are coated with FeO (OH) in an alkaline solution containing Fe (OH) 2 colloid and reduced to form a soft magnetic phase having a thickness of 10 to 100 nm. A method for producing particles for permanent magnets, comprising forming a film. 9. By laser ablation, Fe or Fe-M (M is at least one kind of transition metal such as Co, Ni, Mn) or Fe-MN (M is transition metal such as Co, Ni, Mn). At least one kind of metal) or an alloy having an Fe-N composition from a soft magnetic phase having a width of 10 to 100 nm and a length of 10 to 2000 n.
m are prepared and coated in a hydrolyzable metal compound solution containing R (R is at least one of rare earth elements including Y), Fe, and B to reduce the fine particles. A method for producing particles for permanent magnets, comprising forming a hard magnetic phase coating having a thickness of 10 to 100 nm. 10. One of a hard magnetic phase and a soft magnetic phase having a length of 10 to 100 nm and a length of 10
To 2000 nm fine particles, and on the surface of the fine particles,
The other has a thickness of 10 to 100 by laser ablation.
A method for producing particles for permanent magnets, characterized in that the particles are subjected to a surface treatment with nm and coated. 11. A seed crystal of FeO (OH) is grown in an aqueous solution of ferrous salt having a pH of 4.5 or less, and reduced in a reducing gas to obtain a width of 10 to 100 nm and a length of 10 to 100 nm.
Fine particles having a soft magnetic phase of 2000 nm are prepared, and the fine particles are coated and reduced in a solution of a hydrolyzable metal compound having R (R is at least one of rare earth elements including Y), Fe, and B. By the thickness 10-100
A method for producing particles for permanent magnets, comprising forming a coating of a hard magnetic phase in nm. 12. A seed crystal of FeO (OH) is grown in an aqueous solution of ferrous salt having a pH of 4.5 or less and reduced in a reducing gas to obtain a 10 to 100 nm wide and 10 to 10 nm long.
Fine particles having a soft magnetic phase of 2,000 nm were prepared, and the fine particles having a thickness of 10 to 1 were subjected to laser ablation.
A method for producing particles for permanent magnets, wherein a coating of a hard magnetic phase is formed at a thickness of 00 nm. 13. The surface of a metal particle having a soft magnetic phase,
A metal layer of a hard magnetic phase that does not form a solid solution with the soft magnetic metal is formed by a sputtering method, and fine particles having a width of each of the hard magnetic phase and the soft magnetic phase of 10 to 100 nm and a length of 10 to 2000 nm are formed. A method for producing permanent magnet particles. 14. A sputter target provided with a hard magnetic alloy is provided, and soft magnetic particles are housed in an airtight rotating barrel capable of being evacuated and rotationally stirred, and the surface of the soft magnetic particles is hard magnetically coated by sputtering. 14. The method for producing particles for permanent magnets according to claim 13, wherein: 15. A soft magnetic particle is housed in a vacuum chamber provided with a sputtering target provided with a hard magnetic alloy, the vacuum chamber is vibrated and agitated, and the surface of the soft magnetic particle is coated with a hard magnetic coating by a sputtering method. The method for producing particles for permanent magnets according to claim 13, wherein the particles are formed. 16. A sputtering target provided with a hard magnetic alloy in a vacuum chamber, a belt conveyor arranged opposite to the target, a permanent magnet arranged along the inside of the belt conveyor, and the belt conveyor. A feeder provided on one outer side to supply soft magnetic particles, a vibrator for applying vibration to the feeder, and soft magnetic particles provided on the other end of the belt conveyor and coated with a hard magnetic layer Wherein a hard magnetic coating is formed by sputtering on the surface of the soft magnetic particles adhered to and conveyed to the belt conveyor surface in this vacuum chamber. A method for producing the described particles for permanent magnets. 17. The method for producing particles for permanent magnets according to claim 15, wherein a heater is provided at a position of the belt conveyor facing the collector and the particles attached to the belt conveyor are thermally demagnetized. 18. Fe or Fe-M (M is Co, N
i) at least one of transition metals such as Mn) or a soft magnetic phase metal having an Fe—N composition.
A hard magnetic phase, R (R is at least one of rare earth elements including Y), Fe,
A method for producing particles for permanent magnets, characterized in that crystals are oriented by coating, reducing and heat-treating in a hydrolyzable metal compound solution containing B and B, and then pulverized. 19. Fe or Fe-M (M is Co, N
at least one of transition metals such as i and Mn) or an alloy having a soft magnetic composition having an Fe—N composition;
An alloy of a hard magnetic composition having an Fe-B (B is at least one of rare earth elements including Y) composition, a surface of a rapidly quenched ribbon having a thickness of 10,000 nm or less made of one of the alloys, A method for producing particles for permanent magnets, characterized in that a surface is treated with an alloy to form a coating, which is then heat-treated to orient crystals and pulverize the crystals. 20. The method for producing permanent magnet particles according to claim 13, wherein the heat treatment is performed in a gas containing hydrogen. 21. A permanent magnet, wherein a magnetic field is formed by mixing and bonding an epoxy resin, a nylon resin, or an acrylic resin to the permanent magnet particles according to any one of claims 1 to 4. magnet. 22. A permanent magnet, wherein the particles for a permanent magnet according to claim 1 are sintered at 1000 ° C. or lower.