JPH08277403A - Production of permanent magnet alloy powder for bond magnet and apparatus therefor - Google Patents

Abstract

PURPOSE: To continuously obtain a permanent magnet alloy powder for bond magnet having stable magnetic characteristic by adjusting the pressure in a rapid cooling vessel according to the molten metal surface level in a molten metal storing vessel. CONSTITUTION: A raw material 20 blended into the composition of R-Fe-B base magnet is melted in a melting furnace 3 and stored into a molten metal storing vessel 4. The molten metal 21 in the molten metal storing vessel 4 is dropped on a water-cooling roll 7 rotated at high speed to obtain a rapid cooling strip 22 having amorphous structure or ultra-fine crystal structure of <=1nm average crystal grain diameter by rapid cooling solidification. At the time of tapping this molten metal, the molten metal tapping rate is kept constant by adjusting the pressures in a rapid cooling vessel 2 and a melting vessel 1 according to the molten metal surface level in the molten metal storing vessel 4. After cutting off the obtd. rapid cooling strip 22 into the rapid cooling flakes 23 with a cut-off machine 10, the flakes are pressed into 2-3g/cm<3> apparent sp.gr. with a compressor 11. Further, the pressed flakes are crushed into 3-50μm average powder grain diameter, separately with a crusher, and successively, heat treatment is executed at 600-800 deg.C in inert gas to obtain the magnet alloy powder of fine crystal having 1-30nm average crystal grain diameter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing a permanent magnet alloy powder for various magnets, loudspeakers, and bond magnets, which is optimal for meters and sensors. Diameter is 10n
By combining a method for producing an ultra-quenched alloy ribbon capable of continuously producing an alloy powder having an ultra-fine crystal structure of m or less with a heat treatment for producing a permanent magnet alloy powder for a bonded magnet by a specific heat treatment, The present invention relates to a method and an apparatus for producing a permanent magnet alloy powder for a bond magnet, which continuously produces a fine crystal type magnet alloy powder for a bond magnet having an average crystal grain size of 300 nm or less from a blended raw material.

[0002]

2. Description of the Related Art Magnet alloy powder for R-Fe-B bond magnets is prepared by casting molten metal on a rotating roll mainly made of copper and iron, quenching and solidifying it to produce an amorphous alloy ribbon. Many methods have been studied so far. For example, JP-A-57-210934 and JP-A-60-9852 introduce methods for producing Nd-Fe-B based permanent magnets by a rapid cooling / solidification method using a rotating roll.
A number of similar methods have been studied and reported in universities and research institutes that study magnetic materials, but in each case, several tens to several hundreds of alloys are melted in a nozzle having an orifice at the bottom to release hot water. It is of scale.

As an example of increasing the processing amount, Japanese Patent Application No. 63-
Japanese Patent No. 333829 discloses a method of tilting a melting furnace to pour the molten metal into a container having a tapping nozzle at the bottom and discharge the molten metal onto a rotating roll below the nozzle. However, in order to increase the treatment amount to 50 kg or more so as to be compatible with industrial mass production, not only the melting furnace and the melting tank need to be large, but the bulk specific gravity is 0.01 g / cm ³
A huge quenching tank is required to accommodate a small amount of alloy ribbon, and the equipment becomes very large, resulting in a huge manufacturing cost of the equipment, and a lot of time and a huge amount of time for evacuation and gas replacement. Active gas is required.

[0004]

A soft magnetic phase composed of α-iron and a ferromagnetic alloy containing iron as a main component and a hard magnetic phase having an Nd ₂ Fe ₁₄ B type crystal structure as magnet alloy powders for bonded magnets. Coexistence and the average crystal grain size of each constituent phase is 1 nm to
Permanent magnet alloy powder having a thickness of 50 nm, and Nd ₂ Fe ₁₄
Permanent magnet alloy powder having a hard magnetic phase having a B-type crystal structure as a main phase and an average crystal grain size of 300 nm or less contains a rare earth metal which is easily oxidized. Or, since it needs to be performed in an inert gas, the vacuum pumping time becomes longer as the size of the equipment increases, and the amount of inert gas becomes enormous, resulting in an increase in production efficiency and production cost. Not practical.

In the production of the magnet alloy powder,
It is necessary to increase the melting amount to improve the throughput of the rapid cooling / solidification method using a rotating roll, but to increase the melting amount, it is necessary to increase the size of the melting crucible and the high frequency power source, etc. At the same time, the cost rises, and at the same time, the enlargement of the equipment causes problems such as a long vacuum exhaust time and an enormous amount of inert gas.

On the other hand, since the bulk specific gravity of the alloy ribbon obtained by the rapid cooling / solidification method using a rotating roll is about 0.01 g / cm ³ , the container for recovering the alloy ribbon has a specific gravity of 7 with the same composition. It requires more than 700 times the volume of a cast alloy of 0.5 g / cm ³ . Therefore, if the amount of dissolution is increased and the amount of quenching / solidification is increased in industrial production, a very large collection container is required.

In order to obtain uniform magnetic properties in the magnet alloy powder for bonded magnets, the pressure difference between the melting tank and the quench tank is adjusted according to the change in the head pressure of the molten metal discharged onto the rotating roll. Therefore, it is necessary to keep the molten metal output constant and to produce an alloy ribbon with a homogeneous quenching structure.However, if the melting amount is increased to increase the alloy ribbon production, the change in the melt head pressure will increase. Since the adjustment of the pressure difference between the tanks cannot cope with the change of the molten metal head pressure, there is a problem that the amount of the molten metal is changed and an alloy ribbon having a uniform quenched structure cannot be obtained.

A method of measuring the height of the hot water in the hot water storage container and adjusting the pressure difference between the tanks has been proposed (JP-A-5-75801). However, in a large furnace with a melting amount of 50 kg or more, The volume becomes large, pressure control cannot be achieved quickly enough, and if you try to achieve this forcefully, the exhaust device and the gas injection mechanism for differential pressure control will become significantly large, and a huge construction cost will be required. is there.

In any case, in the production of the magnet alloy powder for bonded magnets, in the conventional quenching / solidifying apparatus using the rotating roll, it is necessary to upsize the apparatus in order to increase the processing amount to the mass production scale. In addition, the work efficiency is lowered, the manufacturing cost and the operating cost of the apparatus are increased, and the magnetic properties are varied, which leads to an increase in the cost of the magnet alloy powder for the bonded magnet.

The present invention is a soft magnetic phase composed of α-iron having a powder particle size of 3 μm to 500 μm, which is a raw material for isotropic bonded magnets, and a ferromagnetic alloy containing iron as a main component, and Nd ₂ Fe.
A hard magnetic phase having a ₁₄ B-type crystal structure coexistent, and an average crystal grain size of each constituent phase is 1 nm to 50 nm, and a permanent magnet alloy powder for a bonded magnet, and a hard magnet having an Nd ₂ Fe ₁₄ B-type crystal structure. Average crystal grain size of 300 nm with magnetic phase as main phase
It is an object of the present invention to provide a method for producing a permanent magnet alloy powder for a bond magnet and an apparatus therefor capable of continuously producing a permanent magnet alloy powder for a bond magnet having the following stable magnetic properties and providing the powder at a low cost.

[0011]

In order to mass produce the magnet powder for bonded magnets, the inventor of the present invention has long experience in preventing the size of equipment such as a melting tank and a melting furnace from increasing in size, reducing manufacturing costs, and evacuation and gas supply. As a result of various studies on a method of producing good quality permanent magnet alloy powder for bonded magnets at low cost without requiring time, the ability of the melting furnace and the ability of a quenching device such as a quenching roll to quench the molten metal into a thin ribbon are almost found. Equalize, melt the molten metal in the melting furnace into a thin ribbon by the quenching device, store the molten metal in a hot water storage container kept at the temperature of the molten metal, and quench the molten metal in the hot water container by the rapid cooling device. When, the melting raw material of the magnet composition is continuously melted in a melting furnace,
The melt that has decreased in the hot water storage container is additionally replenished, and the melt that has been additionally replenished is continuously made into a quench ribbon, and the melt pressure at the tap nozzle changes as the melt level in the hot water storage container decreases. In order to prevent quality and size fluctuations, the melt level in the hot water storage container is detected by the detector, and the pressure in the quench tank is changed according to the change in the head pressure of the melt in the hot water storage container by the detection signal. By doing so, the amount of molten metal depending on the molten metal discharge pressure consisting of the pressure difference between the melting tank and the quenching tank and the head pressure of the molten metal in the hot water storage container is kept constant, and the quality of the quenched ribbon is held uniformly, The present invention has been completed by discovering that cutting and compression of a rapidly cooled ribbon in a rapid cooling tank can prevent an increase in the size of equipment and an increase in gas supply and exhaust time in subsequent steps.

That is, the present invention relates to an R—Fe—B based magnet alloy (where R is one or more of Pr, Nd, and Dy) in a vacuum or an inert gas atmosphere in which a raw material is mixed. After melting in a melting furnace that has a mechanism that can additionally supply the blended raw materials, after pouring this molten metal into a hot water storage container that has a tapping nozzle at the bottom and can maintain the tapping temperature, the molten metal in the hot water storage container is placed directly under the tapping nozzle. When producing an alloy ribbon having an amorphous or ultrafine crystal structure with an average crystal grain size of 1 nm or less by tapping on the placed water-cooling roll and quenching and solidifying, when tapping from the tap nozzle, Depending on the level of the molten metal, control the pressure in the quench tank where the water-cooled roll is placed to maintain a constant amount of tapping, and by the water-cooled roll, the compounding raw materials are additionally supplied to the melting furnace during rapid solidification of the molten metal,
After melting, the operation of supplying the molten metal to the molten metal container again is repeated to continuously produce alloy ribbons, and the produced ribbons are made into flakes by a breaking machine provided in a quench tank, and further by a compressor. after compressing the flakes ^{2g / cm 3 ~3g / cm 3} , and discharged to the quench tank outside having an average powder particle size by a pulverizer compressed flakes and crushed into 3Myuemu～500myuemu,
Heat treatment at 600 ℃ ~ 800 ℃ in an inert gas,
A method for producing a permanent magnet alloy powder for a bonded magnet, comprising continuously producing a fine crystalline permanent magnet alloy powder having an average crystal grain size of 300 nm or less.

Further, according to the present invention, in the above structure,
The composition formula _{Fe 100-xy R x B y} ( where R is Pr, Nd, D
y is one or two or more) and the symbols x and y for limiting the composition range satisfy the following values, and substantially 90% or more of amorphous alloy flakes have an average powder particle size of 3 μm by a pulverizer.
After pulverizing to a particle size of ˜500 μm, substantially 90% or more of the pulverized powder that is amorphous is heated in an inert gas from near the temperature at which crystallization starts to a processing temperature of 600 ° C. to 750 ° C. Is subjected to crystallization heat treatment at 10 ° C./min to 50 ° C./sec to obtain a soft magnetic phase composed of α-iron and a ferromagnetic alloy containing iron as a main component and a hard magnetic phase having an Nd ₂ Fe ₁₄ B type crystal structure. Coexist, and the average crystal grain size of each constituent phase is 1 nm to 5
A method for producing a permanent magnet alloy powder for a bonded magnet having a size of 0 nm is proposed. 3 ≦ x ≦ 6 at% 10 ≦ y ≦ 30 at%

Further, according to the present invention, in the above structure,
The composition formula _{Fe 100-xy R x B y} ( where R is Pr, Nd, D
The alloy flakes having an ultrafine crystal structure with a crystal grain size of 10 nm or less satisfying the following values where the symbols x and y that limit the composition range are After pulverizing to 3 μm to 500 μm,
The pulverized powder having a crystal grain size of 10 nm or less has an average crystal grain size of 300 n at a temperature of 550 ° C. to 800 ° C. in an inert gas.
A permanent magnet alloy powder for a bonded magnet, which has been subjected to a heat treatment for controlling a metallographic structure for grain growth to m to 50 nm and has a hard magnetic phase having an Nd ₂ Fe ₁₄ B type crystal structure as a main phase and an average crystal grain size of 300 nm or less. The manufacturing method of is proposed. 8 ≦ x ≦ 20 at% 4 ≦ y ≦ 10 at%

Further, the present invention comprises a melting tank capable of holding a vacuum or an inert gas atmosphere and adjusting the pressure inside the tank and a quenching tank, the melting tank being R-Fe-B (where R is Pr,
(One or more of Nd and Dy) A melting furnace that melts the compounded raw materials so as to obtain a magnet alloy composition, a hot water storage container that has a tapping nozzle at the bottom and a heating device that holds the tapping temperature, and infiltration of the atmosphere. A mixing raw material supply mechanism that supplies the mixing raw material to the melting furnace while being prevented is provided, and the quenching tank is a water-coolable rotating roll for rapidly solidifying the molten metal discharged from the tapping nozzle to form a rapid cooling ribbon, Obtained bulk specific gravity 0.01 g /
cm ³ ~0.05g / and breaking machine for breaking the quenched ribbons of cm ^3, further bulk specific gravity of the fracture fragments 2g / cm ³ ~3g / c
It has a water-coolable compressor that compresses to m ³ , and an alloy ribbon recovery mechanism that can prevent the intrusion of the atmosphere and discharge the alloy flakes outside the tank. Melting, tapping, rapid solidification without breaking the atmosphere, This is an apparatus for producing a permanent magnet alloy powder for a bonded magnet, which is characterized in that rupture, compression and discharge are performed continuously in parallel.

Further, according to the present invention, in the above structure,
While maintaining the pressure in the melting tank constant, the molten metal level that is poured from the melting furnace to the hot water container is detected, and the detection signal responds to changes in the head pressure of the molten metal that acts on the orifice part of the tapping nozzle in the hot water container. By adjusting the pressure in the quenching tank by adjusting the pressure in the quenching tank, the amount of tapping water that depends on the tapping pressure, which is the sum of the pressure difference between the melting tank and the quenching tank and the head pressure of the molten metal in the hot water storage container, is kept constant and a uniform We also propose an apparatus for producing permanent magnet alloy powder for bonded magnets that continuously produces alloy ribbons with a rapidly cooled and solidified structure.

[0017]

The method of manufacturing the permanent magnet alloy powder for bonded magnets according to the present invention will be described in detail with reference to the manufacturing apparatus shown in FIG.
The apparatus is basically composed of a melting tank 1 having a melting furnace 3 and a quenching tank 2 connected to the lower part of the melting tank 3. In each case, an exhaust port 1a is provided so that a vacuum or an inert gas atmosphere can be maintained in the tank and the pressure in the tank can be adjusted. , 2a and gas supply ports 1b, 2b. On the upper part of the dissolution tank 1 having the exhaust port 1a and the gas supply port 1b on the side wall, the compounded material supply device 8 similarly having the exhaust port 8a and the gas supply port 8b is placed. A tiltable melting furnace 3 and a hot water storage container 4 having a heating device (not shown) on the outer peripheral portion and a hot water discharge nozzle 5 at the lower portion are arranged. The tapping nozzle 5 of the hot water storage container 4 has a melting tank 1 and a quench tank 2.
This hot water discharge nozzle 5 is placed in the partition wall of
A water-cooled roll 7 for forming a quenched ribbon is provided at the lower position.

The quenching tank 2 is connected to an alloy recovery mechanism section 9 arranged vertically for recovering the quenched ribbon 22 obtained by the water cooling roll 7. The mechanism section 9 is connected to the alloy cooling mechanism section 9 by the water cooling roll 7. A breaker 10 for breaking the quenched ribbon 22 sent out, a hopper, and a compressor 11 for compressing the broken quenching thin piece 23 through the ball valve 12 are built in, and an exhaust port 9a and a gas are provided on a side wall below the ball valve 12. It has a supply port 9b. The compressor 11 compresses the rapidly cooled thin piece 23 that has fallen into the cylinder with a piston, and the outside air is compressed during the compression.
The quenching thin piece 23 compressed from the head side can be discharged without entering into the inside.

In the hot-water storage container 4, a refractory float 15 for detecting the level of the melt and a CCD camera 14 for detecting the vertical movement of the float 15 are provided in the upper part of the peep window 13 provided in the upper part of the melting tank 1, and the CCD is arranged. Float 15 detected by camera 14
The up-and-down movement of is calculated by calculating the tapping pressure of the tapping nozzle 5 from a signal P ₁ that detects the pressure in the melting tank 1 and a signal P ₂ that detects the pressure in the quenching tank 2 by a calculator, and is set in advance. A deviation signal from the tapping pressure is sent to the gas supply port 2b of the quench tank 2 so that the tapping pressure is controlled to be constant, and the deviation signal is sent to the gas feed port 1b of the melting tank 1 to melt the tank 1. The gas supply port 1 is adjusted according to the exhaust volume so that the internal pressure becomes constant.
Gas is supplied from b and 2b. In the present invention, a refractory float and CC are used as a molten metal level detection device.
I mentioned the D camera, but the reflected light of the laser beam was CCD.
Known methods such as a method of measuring with a camera, a thermocouple method, a method of inserting a contactor, and a γ-ray method can be used.

The raw material supply device is a raw material supply device 20 in which the raw material 20 is blended so as to have the required composition of the R—Fe—B magnet while preventing the invasion of the atmosphere into the melting tank 1 held in vacuum or an inert gas. 8 is supplied to the melting furnace 3 and melted at a required temperature, and the obtained molten metal 21 is poured into the melting furnace 3 and stored in a hot water storage container 4 which is kept at the required temperature. In the figure, 6 is a funnel that collects the molten metal in the hot-water storage container 4 at the time of tilting. The molten metal 21 of the hot water storage container 4 is placed immediately below the tapping nozzle 5 at the bottom of the container 4 and drops onto a water-cooling roll 7 that rotates at high speed, and is rapidly solidified to have an amorphous or fine crystal structure with an average crystal grain size of 10 nm or less. A quenched ribbon 22 having

Molten metal 21 from the tapping nozzle 5 to the water cooling roll 7
When the hot water is discharged, as described above, the pressure of the hot water is kept constant by adjusting the tank pressures of the quenching tank 2 and the melting tank 1 according to the melt level in the storage container 4, and the water cooling roll 7 During the rapid solidification of the molten metal 21 due to, the compounding raw material 20 is supplied to the melting furnace 3 from the compounding raw material supply device 8,
After being melted in, the operation of tilting the molten metal 21 into the hot water storage container 4 is repeated, and the rapid cooling thin strip 22 is continuously made by the water cooling roll 7.
Can be manufactured.

The apparent density (bulk specific gravity) obtained was 0.01 g.
/ Cm ^{3 to} 0.05 g / cm ³ of the quenched ribbon 22 is immediately ruptured by the breaking machine 10 to give an apparent density of 50 g or less of 0.1 g.
/ Cm ^{3 to 1} g / cm ³ of the quenched thin piece 23, the thin piece 23 is compressed by the compressor 11 to have an apparent density of 2 g / cm ³ to
Compress to ³ g / cm ³ . The compressed alloy flakes discharged from the compressor 11 and compressed are separately crushed by a crusher so that the average powder particle size becomes 3 μm to 500 μm, and then heat-treated at 600 ° C. to 800 ° C. in an inert gas in a heat treatment furnace. As a result, fine crystal permanent magnet alloy powders for bond magnets having an average crystal grain size of 1 nm to 300 nm can be continuously produced.

In the present invention, when the molten metal 21 is discharged from the molten metal discharge nozzle 5, since the diameter of the orifice of the molten metal discharge nozzle 5 is as small as 0.5 mm to 2 mm, when the molten metal 21 has a high viscosity of 1.7 Pa · S or more, Since the molten metal 16 cannot be tapped due to the frictional force between the molten metal 16 and the inner wall surface of the tapping nozzle 5, the pressure in the quenching tank 2 is lower than the pressure in the quenching tank 2 by simply tilting it from the melting furnace 3 into the melting tank 4. 1 and the quenching layer 2 have a pressure difference, and the hot water discharge nozzle 5 is caused by this pressure difference.
The molten metal 21 can be discharged from the molten metal. Further, when the viscosity of the molten metal 21 is less than 1.7 Pa · S due to the high melting temperature, tapping from the melting furnace 3 to the hot water storage container 4 immediately starts tapping, so tapping with a mechanism that can be opened and closed at the bottom By providing the nozzle 5, the hot water discharge operation can be performed.

In the present invention, when a Cu roll is used as the quench roll, the peripheral surface speed of the roll is 10 to 50 mm, although it depends on the cooling capacity of the attached water cooling device.
The range of / sec is preferable because a suitable quenched structure can be obtained.
That is, if the peripheral speed is less than 10 mm / sec, an amorphous structure is not formed, and if the peripheral surface speed exceeds 50 mm / sec, it is not preferable because a fine crystal aggregate that can obtain good hard magnetic properties is obtained during crystallization. . In addition, the attached water cooling device must satisfy the requirement to steadily remove the heat of solidification, and it is calculated according to the latent heat of solidification and the amount of tapping water per unit time, and the balance is exceeded. It must be a material and at least about 20 kcal / hr is required.

By the manufacturing method of the present invention, substantially 90
While% or more amorphous quenched foils is obtained, the magnet composition represents the composition formula _{Fe 100-xy R x B y} , symbol x to limit the composition ranges, y can satisfy the following values, 3 ≦ x ≦ 6 at% 10 ≦ y ≦ 30 at% The quenched flakes have an average powder particle size of 3 μm to 5 by a pulverizer.
After being pulverized to have a particle size of 00 μm, the pulverized powder is substantially 90% or more amorphous and the temperature is increased from around the temperature at which crystallization starts in an inert gas to 600 ° C. to 750 ° C. By performing a crystallization heat treatment at a rate of 10 ° C./min to 50 ° C./sec, a soft magnetic phase composed of α-iron and a ferromagnetic compound containing iron as a main component and a hard structure having an Nd ₂ Fe ₁₄ B type crystal structure. Magnetic phase coexists and average crystal grain size of each constituent phase is 1n
Microcrystalline magnet powder of m-50 nm is obtained.

In the present invention, the reason for limiting the values of x and y in the composition formula is that when R is less than 3 at%, iHc of 3.0 kOe or more cannot be obtained, and when it exceeds 6 at%, Br of 6 kG or more is obtained. Since it does not exist, the range is 3 at% to 6 at%. The preferable range of R is 4 to 5.5 at%.
Further, if B is less than 10 at%, an amorphous structure cannot be obtained even if the ultra-quenching method is used, iHc of less than 2.0 kOe is obtained even if heat treatment is applied, and if it exceeds 30 at%, it becomes 3.0 k.
Since iHc higher than Oe cannot be obtained, 10 at% to 30
The range is at%. The preferred range of B is 15 at%
It is 20 at%.

In the present invention, the crystallization heat treatment temperature is set to 6
The reason for limiting the temperature to 00 to 750 ° C is N below 600 ° C.
iHc is not expressed because the d ₂ Fe ₁₄ B phase does not precipitate, and grain growth is remarkable when the temperature exceeds 750 ° C., iHc, Br
And the squareness of the demagnetization curve is deteriorated, which is not preferable. Further, in the present invention, if the temperature rising rate from around the temperature at which crystallization of heat treatment starts is less than 10 ° C./minute, grain growth will occur during temperature rising, and good hard magnetic characteristics will be obtained. No iHc of 3 kOe or more was not obtained, and
If it exceeds 50 ° C / sec, the Nd ₂ Fe ₁₄ B phase formed after passing over 600 ° C is not sufficiently precipitated, iHc is not only lowered, but also near the Br point in the second quadrant of the magnetization curve. The demagnetization curve has a decrease in magnetization, and (BH) max deteriorates, which is not preferable.

In the present invention, a part of Fe is Al, S
i, Ti, V, Cr, Mn, Co, Ni, Cu, Zn,
By substituting one or several of Ga, Zr, Nb, Mo, Ag, Pt, Au, and Pb in combination, the average crystal grain size is reduced to 1 nm to 30 nm, so that the residual magnetic flux density is improved. , Nd ₂ Fe that further develops coercive force
_{Since the} volume ratio of the hard magnetic phase having the ₁₄ B-type crystal structure in the metal structure increases, the coercive force improves, and at the same time, the heat resistance and the corrosion resistance also improve. However, when the substitution amount of Fe is 0.1% or less, such an effect cannot be obtained, and when the substitution amount of Fe is 50% or more, good magnetization characteristics cannot be obtained because the saturation magnetization is significantly reduced. 0.1%
-50% range. The preferable substitution amount for Fe is 2% to 20%.

In the present invention, the reason why the average crystal grain size of each constituent phase is limited to 1 nm to 50 nm is that it is difficult to obtain an average crystal grain size of less than 1 nm in industrial production.
If it exceeds 50 nm, the squareness of the demagnetization curve is significantly deteriorated, and the required magnetic characteristics cannot be obtained. In addition, the quenched ribbon of the substantially amorphous structure of the present invention is 3 μm to 5 μm with a pulverizer.
The reason for pulverizing to 00 μm is not preferable because the surface area of the pulverized powder is increased when the particle diameter is less than 3 μm, which is not preferable because the molded body density of the bonded magnet decreases, and when it exceeds 500 μm, the voids inside the bonded magnet increase and the molded material density decreases. Therefore, it is not preferable.

According to the present invention, the crystal grain size is 10 nm.
The following magnet composition obtained the quenched ribbon having ultra fine crystalline structure, composition formula _{Fe 100-xy R x B y} ( where R is Pr, N
d, one or more of Dy), and the symbols x and y that limit the composition range satisfy the following values: 8 ≦ x ≦ 20 at%, 4 ≦ y ≦ 10 at% Average powder particle size is 3 μm to 500
After crushing to a particle size of μm, a crushed powder having a crystal grain size of 10 nm or less is grown in an inert gas at a temperature of 550 ° C. to 800 ° C. to have an average crystal grain size of 300 nm to 50 nm. After heat treatment, the average grain size of the hard magnetic phase having the Nd ₂ Fe ₁₄ B type crystal structure as the main phase is 30
A magnet alloy powder for a bonded magnet having a particle size of 0 nm or less is obtained.

In the present invention, the reason for limiting the values of x and y in the composition formula is that when R is less than 8 at%, a cubic crystal structure having the same structure as α-Fe exists, so that i of 80 kOe or more is present.
Hc and Br of 7 kG or more were not obtained, and 2
If it exceeds 0 at%, the R-rich non-magnetic phase increases and the saturation magnetization decreases, which is not preferable.
The range is at%. The preferred range of R is 10 at%
It is 16 at%. When B is less than 4 at%, a rhombohedral structure is formed, so iHc of 8 kOe or more and Br of 7 kG or more cannot be obtained, and when it exceeds 10 at%, saturation magnetization is unfavorably reduced, and therefore 4 at% to 10 at%.
Range. The preferred range of B is 6 at% to 8 at%
Is.

Fe may be partially or wholly replaced with Co, and within the range of 0.1% to 20% with respect to the amount of Fe + Co, Al, Si, Ti, V, Cr, Mn, N
i, Cu, Ga, Zr, Nb, Mo, Ag, Pt, A
Even if u and Pb are contained, they do not deteriorate the magnetic properties so much and are allowed.

The reason for limiting the crystal grain size of the quenched ribbon to 10 nm or less is not preferable when it exceeds 10 nm because the structure contains coarse α-Fe particles. The reason for crushing the quenched ribbon of the present invention to 3 μm to 500 μm with a crusher is 3 μm.
If it is less than 500 μm, the surface area of the pulverized powder increases, and the molded density of the bonded magnet decreases, which is not preferable, and if it exceeds 500 μm, voids inside the bonded magnet increase and the density of the molded product decreases, which is not preferable. The reason why the metallographic structure control heat treatment temperature in the present invention is limited to 550 ° C to 800 ° C is 550 ° C.
When the temperature is less than 80 ° C, the grains do not grow into grains necessary for obtaining iHc of 8 KOe or more, and when the temperature exceeds 800 ° C, the average grain size is 30.
It becomes 0 nm or more and Br is remarkably lowered, which is not preferable.

[0034]

【Example】

Example 1 As a manufacturing apparatus, a continuous manufacturing apparatus according to the present invention shown in FIG. 1 was used, and 20 kg of compounded raw material was charged into a melting furnace from a raw material supply apparatus so as to have a Nd _4.5 Fe ₇₇ B _18.5 at% magnet composition and melted. After 20 minutes, a molten metal having a temperature of 1350 ° C. is placed on the outer peripheral portion by a high-frequency heating device, and the molten metal is charged into a 3.2 l storage container capable of holding the molten metal at 1300 ° C., and then freely opened and closed at the bottom of the molten metal storage container. 1,200 rpm from the hot water nozzle
A water-cooled Cu roll having an outer diameter of 350 mm and an outer diameter of 350 mm was poured onto the outer peripheral surface of the water-cooled Cu roll, and 20 kg of a rapidly cooling thin ribbon having an amorphous structure and a thickness of 40 μm and a width of 3.0 mm was rapidly solidified in 22 minutes. At this time, during the production of the quenched ribbon, the compounded raw materials continuously charged in the melting furnace are melted, and the reduced melt in the hot water storage container is replenished with additional melted metal, melting, hot storage, rapid cooling. The solidification process is repeated 5 times in succession, and 96 kg of quenched thin strips with an apparent density (bulk specific gravity) of 0.02 g / cm ³ are continuously cast.
Manufactured.

The quenched ribbon thus obtained was subsequently crushed by a breaking machine in a quench tank to give an apparent density of 0.8 g / cm ³ or less.
The thin pieces were compressed into a compressor at a pressure of 6.4 kg / cm ³ , compressed to an apparent density of 2.4 g / cm ³ , and then discharged to the outside of the compressor. After that, the compressed alloy flakes were crushed by a crusher to an average powder particle size of 150 μm, and then the temperature was raised from 30 ° C./min to a treatment temperature of 580 ° C. to 640 ° C. at which crystallization started in an inert gas. Crystallization heat treatment is performed, and then pulverization is performed to coexist a soft magnetic phase made of α-iron and a ferromagnetic alloy containing iron as a main component and a hard magnetic phase having an Nd ₂ Fe ₁₄ B type crystal structure, and each constituent phase A magnet alloy powder for a bonded magnet having an average crystal grain size of 50 nm was obtained.

A binder made of epoxy resin was mixed with the obtained alloy powder at a ratio of 3 at%, and then 12 nm
A bonded magnet having dimensions of 12 nm and 8 nm was prepared. The obtained bonded magnet has a density of 6 g / cm ³ , and its magnetic characteristics are
iHc = 3.5 kOe, Br = 8.4 kG, BHmax
= 5.5 MGOe.

Example 2 Using the same manufacturing apparatus as in Example 1, Nd ₁₃ Fe ₈₀ B ₇ a
To obtain a t% magnet composition, it was melted and rapidly solidified under the same conditions as in Example 1 to prepare a quenched thin piece having an ultrafine crystal structure with a crystal grain size of 10 nm or less, and then an average powder with a pulverizer. After pulverizing to a particle size of 150 μm, pulverized powder having a crystal grain size of 10 nm or less is heat-treated at 650 ° C. for 10 minutes in an inert gas to control the metallographic structure to grow the average crystal grain size to 200 nm. , Nd ₂ Fe ₁₄ B type crystal structure having a hard magnetic phase as a main phase and an average crystal grain size of 200 nm
The following magnetic alloy powder for bonded magnets was obtained. A bond magnet was prepared from the obtained alloy powder under the same conditions as in Example 1. The obtained bond magnet had a density of 6 g / cm ³ , and its magnetic characteristics were iHc = 9.2 kOe, Br = 6.5 kG, BHm.
It was ax = 9MGOe.

[0038]

The present invention, as is apparent from the examples,
The capacity of the melting furnace and the capacity of the quenching roll device for quenching the molten metal into a thin strip are made almost equal, making it possible to achieve continuity and preventing the increase of gas supply and exhaust time in the device. Before quenching the molten metal into a thin ribbon with a quenching device,
When the molten metal is stored in the hot water storage device that is kept at the tapping temperature, and when the molten metal in the hot water storage device is made into a rapid cooling ribbon, the raw materials of the magnet composition are continuously melted in the melting furnace and Of the molten metal that has been reduced, the melt that has been supplemented is continuously quenched and thinned, and the level of the molten metal in the hot water storage container is detected by a detector, and the orifice of the tap nozzle in the hot water storage container is detected by the detection signal. By adjusting the pressure of the quench tank in response to changes in the head pressure of the molten metal working on the part, it depends on the pressure difference between the melting tank and the quench tank and the tapping pressure, which is the head pressure of the molten metal in the hot water container. The amount of tapping water can be kept constant and the quality of the quenched ribbon can be kept uniform. Furthermore, by cutting and compressing the quenched ribbon in the quench tank, the equipment in the subsequent process can be enlarged. Magnets for bonded magnets that have stable magnetic characteristics without The can be manufactured at low cost in mass production scale.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an outline of a manufacturing apparatus for manufacturing a permanent magnet alloy powder for a bonded magnet according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Melting tank 1a, 2a, 8a, 9a Exhaust port 1b, 2b, 8b, 9b Gas supply port 2 Quenching tank 3 Melting furnace 4 Hot water storage container 5 Hot water nozzle 6 Roto 7 Water cooling roll 8 Blended raw material supply device 9 Alloy recovery mechanism part 10 Breaking machine 11 Compressor 12 Ball valve 13 Viewing window 14 CCD camera 15 Floating 20 Blended material 21 Molten metal 22 Rapid cooling ribbon 23 Rapid cooling flakes

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[Procedure amendment]

[Submission date] August 17, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction content]

[0019] The reservoir 4 is arranged refractory steel float 15 for detecting the soluble water level, arranged in viewing window 13 top having a CCD camera 14 in the dissolution tank 1 top for detecting the vertical movement of the float 15 and, the displacement of the vertical movement of the float 15, which is detected by the CCD camera 14, in the arithmetic unit as shown in FIG. 1, detects the pressure of the quench tank 2 and the signal P ₁ detects the pressure in the dissolution tank 1 Calculated together with the generated signal P ₂ , the tapping pressure of the tapping nozzle 5 is calculated, and a deviation signal from the preset tapping pressure is sent to the gas supply port 2b of the quenching tank 2 so that the tapping pressure is controlled to be constant. At the same time, the deviation signal is sent to the gas supply port 1b of the dissolution tank 1, and the gas supply ports 1b, 1b,
Gas is supplied from 2b. In this invention, a refractory float and a CCD camera were mentioned as the molten metal level detection device, but a method of measuring reflected light of a laser beam with a CCD camera, a thermocouple method, a method of inserting a contact,
A known method such as a γ-ray method can be used.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction content]

Molten metal 21 from the tapping nozzle 5 to the water cooling roll 7
There upon tapping, as described above, depending on the melt level of savings hot water container 4, by adjusting the bath in the pressure of the quench tank 2 and the dissolving tank 1, tapping amount is held constant, also water-cooled roll During the rapid solidification of the molten metal 21 by 7, the compounding raw material 20 is supplied to the melting furnace 3 from the compounding raw material supply device 8 and the melting furnace 3
After being melted in, the operation of tilting the molten metal 21 into the hot water storage container 4 is repeated, and the rapid cooling thin strip 22 is continuously made by the water cooling roll 7.
Can be manufactured.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

In the present invention, when the molten metal 21 is discharged from the molten metal discharge nozzle 5, since the diameter of the orifice of the molten metal discharge nozzle 5 is as small as 0.5 mm to 2 mm, when the molten metal 21 has a high viscosity of 1.7 Pa · S or more, Since the molten metal 23 cannot be tapped due to the frictional force between the molten metal 23 and the inner wall surface of the tapping nozzle 5, the pressure in the quenching tank 2 is lower than the pressure in the quenching tank 2 so that the melting tank 3 is simply poured into the hot water storage container 4. 1 and the quenching layer 2 have a pressure difference, and the hot water discharge nozzle 5 is caused by this pressure difference.
The molten metal 21 can be discharged from the molten metal. Further, when the viscosity of the molten metal 21 is less than 1.7 Pa · S due to the high melting temperature, tapping from the melting furnace 3 to the hot water storage container 4 immediately starts tapping, so tapping with a mechanism that can be opened and closed at the bottom By providing the nozzle 5, hot water discharge operation can be performed.

[Procedure amendment 4]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

FIG.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B22F 9/10 B22F 9/10 C22C 38/00 303 C22C 38/00 303A 303S H01F 1/06 H01F 1 / 06 A

Claims (5)

[Claims] 1. An R-Fe-B magnet alloy (where R is P
(1 or more of r, Nd, Dy) The raw materials mixed so as to have a composition are melted in a melting furnace having a mechanism capable of additionally supplying the mixed raw materials in a melting tank in a vacuum or an inert gas atmosphere, and then the molten metal Is poured into a hot water storage container that has a hot water discharge nozzle at the bottom and can hold the hot water temperature, and then the molten metal in the hot water storage container is tapped onto a water-cooling roll placed immediately below the hot water discharge nozzle to rapidly cool it.
When producing an alloy ribbon having an amorphous or ultrafine crystal structure with an average crystal grain size of 1 nm or less by solidification, at the time of tapping from the tap nozzle, a water cooling roll is arranged according to the level of the molten metal in the hot water storage container. The pressure in the tank is controlled to maintain a constant amount of molten metal, and the work of repeatedly supplying the blended raw material to the melting furnace during the rapid solidification of the molten metal by the water-cooled roll and then melting the molten metal and then supplying the molten metal to the molten metal container is repeated. To continuously produce alloy ribbons, and the produced ribbons are made into thin pieces by a breaking machine provided in a quenching tank, and further, 2g / thick pieces are made by a compressor.
After being compressed to cm ³ to ³ g / cm ^3, it is discharged to the outside of the quenching tank, and the compressed flakes are pulverized by a pulverizer to have an average powder particle diameter of 3 μm to 5
After pulverizing to a size of 00 μm, 60 in an inert gas
Heat treatment at 0 ° C to 800 ° C is performed to obtain an average crystal grain size of 300n.
A method for producing a permanent magnet alloy powder for a bonded magnet, which comprises continuously producing a fine crystalline permanent magnet alloy powder having a particle size of m or less. Wherein the composition formula _{Fe 100-xy R x B y} ( where R is Pr, Nd, one or two or more Dy) represents the symbol x to limit the composition range, y satisfies the following value The alloy flakes that are substantially 90% or more amorphous are pulverized by a pulverizer so that the average powder particle size is 3 μm to 500 μm, and then the pulverized powder that is substantially 90% or more amorphous in an inert gas. In the above, crystallization heat treatment is performed such that the temperature rising rate from the temperature near the start of crystallization to the processing temperature of 600 ° C to 750 ° C is 10 ° C / min to 50 ° C / sec, and α-iron and iron are the main components. _2. The bond magnet according to claim 1, wherein a soft magnetic phase made of a ferromagnetic alloy and a hard magnetic phase having a Nd ₂ Fe ₁₄ B type crystal structure coexist, and the average crystal grain size of each constituent phase is 1 nm to 50 nm. For manufacturing permanent magnet alloy powder for automobiles. 3 ≦ x ≦ 6 at% 10 ≦ y ≦ 30 at% 3. A composition formula _{Fe 100-xy R x B y} ( where R is Pr, Nd, one or two or more Dy) represents the symbol x to limit the composition range, y satisfies the following value The alloy flakes having an ultrafine crystal structure with a crystal grain size of 10 nm or less were pulverized by a pulverizer so that the average powder grain size was 3 μm to 500 μm, and the pulverized powder having a crystal grain size of 10 nm or less was placed in an inert gas. And an average grain size of 300 nm to 50 nm at a temperature of 550 ° C. to 800 ° C., a heat treatment for controlling a metal structure is performed, and a hard magnetic phase having an Nd ₂ Fe ₁₄ B type crystal structure as a main phase is used as an average. The method for producing a permanent magnet alloy powder for a bonded magnet according to claim 1, wherein the crystal grain size is 300 nm or less. 8 ≦ x ≦ 20 at% 4 ≦ y ≦ 10 at% 4. A melting tank capable of holding a vacuum or an inert gas atmosphere and adjusting the pressure in the tank and a quenching tank, wherein the melting tank is R-Fe-B (where R is one of Pr, Nd and Dy). Or two or more) A melting furnace that melts the raw materials to obtain a magnet alloy composition, a hot water storage container that has a hot water outlet nozzle at the bottom and a heating device that maintains the hot water temperature, and a raw material mixture that prevents atmospheric air from entering. The quenching tank is equipped with a compounded raw material supply mechanism for supplying the molten metal to the melting furnace, and the quenching tank is a water-coolable rotating roll for rapidly solidifying the molten metal discharged from the tapping nozzle into a quenching ribbon, and the obtained quenching thin film. A breaking machine for breaking the belt,
It has a water-cooled possible compressor, and a possible alloy ribbon recovery mechanism discharged to prevent ingress of atmospheric alloy flakes Sogai to the fracture fragment further compressed to a bulk density 2g / cm ³ ~3g / cm ³ , Melting, tapping, rapid solidification, rupture, compression without breaking the atmosphere,
An apparatus for producing permanent magnet alloy powder for bonded magnets, which discharges in parallel and continuously. 5. While maintaining a constant pressure in the melting tank,
Detecting the level of molten metal that has been poured into the hot water storage container from the melting furnace, and adjusting the pressure in the quench tank in accordance with the change in the head pressure of the molten metal working at the tap nozzle orifice in the hot water storage container by the detection signal The amount of tapping is dependent on the tapping pressure, which is the sum of the pressure difference between the tank and the quenching tank and the head pressure of the molten metal in the hot water storage container. It manufactures, The manufacturing apparatus of the permanent magnet alloy powder for bond magnets of Claim 4 characterized by the above-mentioned.