WO2011007758A1 - R-t-b系焼結磁石の製造方法およびr-t-b系焼結磁石 - Google Patents
R-t-b系焼結磁石の製造方法およびr-t-b系焼結磁石 Download PDFInfo
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- WO2011007758A1 WO2011007758A1 PCT/JP2010/061776 JP2010061776W WO2011007758A1 WO 2011007758 A1 WO2011007758 A1 WO 2011007758A1 JP 2010061776 W JP2010061776 W JP 2010061776W WO 2011007758 A1 WO2011007758 A1 WO 2011007758A1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/24—After-treatment of workpieces or articles
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C19/00—Alloys based on nickel or cobalt
- C22C19/07—Alloys based on nickel or cobalt based on cobalt
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C28/00—Alloys based on a metal not provided for in groups C22C5/00 - C22C27/00
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/02—Making ferrous alloys by powder metallurgy
- C22C33/0257—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements
- C22C33/0278—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements with at least one alloying element having a minimum content above 5%
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/10—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of nickel or cobalt or alloys based thereon
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/16—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of other metals or alloys based thereon
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
- H01F41/0293—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets diffusion of rare earth elements, e.g. Tb, Dy or Ho, into permanent magnets
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/24—After-treatment of workpieces or articles
- B22F2003/241—Chemical after-treatment on the surface
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C2202/00—Physical properties
- C22C2202/02—Magnetic
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
- H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
- H01F1/047—Alloys characterised by their composition
- H01F1/053—Alloys characterised by their composition containing rare earth metals
- H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
- H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
- H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
- H01F1/0575—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together
- H01F1/0577—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together sintered
Definitions
- the present invention relates to a method for producing an RTB-based sintered magnet (T is a transition metal element containing Fe) having an R 2 T 14 B type compound (R is a rare earth element) as a main phase, and in particular, a light rare earth
- the element RL (at least one of Nd and Pr) is contained as the main rare earth element R, and a part of the light rare earth element RL is a heavy rare earth element RH (at least one selected from the group consisting of Dy and Tb).
- the present invention relates to a method for manufacturing a substituted RTB-based sintered magnet.
- RTB-based sintered magnets with Nd 2 Fe 14 B-type compounds as the main phase are known as the most powerful magnets among permanent magnets, including voice coil motors (VCM) for hard disk drives, It is used for various motors such as motors for hybrid vehicles and home appliances. Since part or all of Nd may be replaced by another rare earth element R, and part of Fe may be replaced by another transition metal element, Nd 2 Fe 14 B type compound is R 2 T 14 Sometimes expressed as a B-type compound. A part of B can be replaced by C (carbon).
- the RTB-based sintered magnet Since the RTB-based sintered magnet has a reduced coercive force at a high temperature, irreversible demagnetization that is demagnetized by high-temperature exposure occurs. In order to avoid irreversible demagnetization, when used for a motor or the like, it is required to maintain a high coercive force even at a high temperature. In order to satisfy this, it is necessary to increase the coercive force at room temperature or reduce the change in coercive force up to the required temperature.
- R 2 T 14 Nd is a light rare-earth element RL in the B type compound in phase with the heavy rare-earth element RH (Dy, Tb), is known to improve the coercive force.
- RH heavy rare-earth element
- Patent Document 1 A method of diffusing inside (hereinafter referred to as “vapor deposition diffusion”) is disclosed.
- vapor deposition diffusion an RTB-based sintered magnet body and an RH bulk body are arranged to face each other with a predetermined interval inside a processing chamber made of a refractory metal material.
- the processing chamber includes a member that holds a plurality of RTB-based sintered magnet bodies and a member that holds an RH bulk body.
- the step of arranging the RH bulk body in the processing chamber, the step of placing the holding member and the net, the step of arranging the sintered magnet body on the net, and further the holding member and the net thereon A series of operations such as a step of placing, a step of arranging the upper RH bulk body on the net, and a step of performing vapor deposition diffusion by sealing the processing chamber are required.
- Patent Document 2 discloses that a low-boiling Yb metal powder and a Nd—Fe—B based sintered magnet molded body are combined with a heat resistant sealed container for the purpose of improving the magnetic properties of the Nd—Fe—B based intermetallic compound magnetic material. It is disclosed that a Yb metal film is uniformly deposited on the surface of a sintered magnet compact and heated to diffuse the rare earth element from this film into the sintered magnet (patent). Example 5 of document 2).
- Patent Document 2 if a rare earth metal having a high saturated vapor pressure such as Yb, Eu, and Sm is used, the formation of the coating on the RTB-based sintered magnet body and the diffusion from the coating Can be performed by heat treatment in the same temperature range (for example, 800 to 850 ° C.), but according to Patent Document 2, in order to sorb rare earth elements having a low vapor pressure such as Dy and Tb, It is necessary to selectively heat the rare earth metal to a high temperature by induction heating using a high frequency heating coil.
- a rare earth metal having a high saturated vapor pressure such as Yb, Eu, and Sm
- the present invention has been made in view of the above circumstances, and its object is to mass-produce a step of diffusing heavy rare earth elements RH such as Dy and Tb from the surface of the sintered magnet body without reducing the residual magnetic flux density. It is an object of the present invention to provide a method for producing an RTB-based sintered magnet that is suitable for the above.
- the manufacturing method of the RTB-based sintered magnet according to the present invention includes a step of preparing an RTB-based sintered magnet body, and a metal or alloy of heavy rare earth element RH (at least one of Dy and Tb) Preparing an RH diffusion source comprising: loading the RTB-based sintered magnet body and the RH diffusion source into a processing chamber so as to be relatively movable and close to or in contact with each other; An RH diffusion step in which a heat treatment at 500 ° C. or more and 850 ° C. or less is performed for 10 minutes or more while continuously moving the RTB-based sintered magnet body and the RH diffusion source in the processing chamber or intermittently; Include.
- the RH diffusion step includes a step of rotating the processing chamber.
- the processing chamber in the RH diffusion step, is rotated at a peripheral speed of 0.01 m / s or more.
- the heat treatment in the RH diffusion step is performed by adjusting the internal pressure of the processing chamber to 100 kPa or less.
- the heat treatment in the RH diffusion step is performed by heating both the RTB-based sintered magnet body and the RH diffusion source by heating the processing chamber.
- the present invention it is possible to diffuse heavy rare earth elements RH such as Dy and Tb from the surface of the sintered magnet body to the inside even under conditions where the diffusion treatment temperature is lower than that of the known technology and the atmospheric pressure is relatively high.
- the present invention for example, by rotating, swinging, or vibrating the processing chamber during the diffusion process, it is possible to avoid welding in which the diffusion source is melted by heating and joined to the sintered magnet body.
- the charging operation is simple and the mass productivity is excellent.
- the RTB-based sintered magnet body and the RH diffusion source are charged into a processing chamber (or a processing container) so as to be relatively movable and close to or in contact with each other. It is kept in a temperature range of from °C to 850 °C.
- the RTB-based sintered magnet body and the RH diffusion source are continuously connected in the processing chamber by rotating or swinging the processing chamber or applying vibration to the processing chamber.
- the position of the contact portion between the RTB-based sintered magnet body and the RH diffusion source is changed, or the RTB-based sintered magnet body and the RH diffusion source are moved. While adjoining and separating, the supply by vaporization (sublimation) of the heavy rare earth element RH and the diffusion to the sintered magnet body are simultaneously performed (RH diffusion step).
- the temperature range of 500 ° C. or more and 850 ° C. or less is a temperature at which rare-earth element diffusion can proceed in an RTB-based sintered magnet, but is a temperature at which vaporization (sublimation) of Dy and Tb hardly occurs.
- the present inventor performs heat treatment while bringing the RH diffusion source into contact with the RTB-based sintered magnet body (hereinafter sometimes simply referred to as “sintered magnet body”) in the processing chamber, it is surprising.
- the heavy rare earth element RH diffuses into the sintered magnet body and increases its coercive force.
- the reason why diffusion occurs in such a temperature range is considered to be that the RH diffusion source and the sintered magnet body are close to or in contact with each other, and the distance between the two becomes sufficiently small.
- the present invention previously inserts a sintered magnet body and an RH diffusion source into a processing chamber so as to be relatively movable and close to or in contact with each other.
- the above welding was prevented and the intended RH diffusion was realized.
- the RH diffusion source and the sintered magnet body are fixed at a fixed location and contacted for a long time.
- the RH diffusion may be performed while the contact portion between the RH diffusion source and the sintered magnet body is moved continuously or intermittently, or the RH diffusion source and the sintered magnet body are moved closer to or away from each other. It becomes possible to perform a process.
- the sintered magnet body and the RH diffusion source are charged into the processing chamber so as to be relatively movable and close to or in contact with each other” means, as described above, the RH diffusion process after the charging process.
- the sintered magnet body and the RH diffusion source move continuously or intermittently in the processing chamber, so that the RH diffusion source and the sintered magnet body are fixed at a fixed position for a long time (for example, 2 at 850 ° C. Min) means charging without being constrained by contact or proximity. Therefore, in the present invention, as described in Patent Document 1, it is not necessary to arrange the sintered magnet body and the RH diffusion source at predetermined positions.
- the sintered magnet body As a method of moving the sintered magnet body and the RH diffusion source continuously or intermittently in the processing chamber in the RH diffusion process, the sintered magnet body is continuously or intermittently generated without causing any chipping or cracking. If it is possible to move the contact portion between the RH diffusion source and the sintered magnet body, or to move the RH diffusion source and the sintered magnet body close to or away from each other, the processing chamber can be rotated and swung as described above. In addition to the method of applying vibration to the processing chamber from the outside, various methods such as providing a stirring means in the processing chamber are possible.
- the RH supply source is close to or in contact with the sintered magnet body, so that the heavy rare earth element RH sublimated from the RH diffusion source is effective. Is supplied to the sintered magnet body and can diffuse through the grain boundary.
- a heavy rare earth element RH film (RH film) is formed on the surface of the sintered magnet body and then diffused into the sintered magnet body by heat treatment, the main phase crystal grains are formed in the surface layer region in contact with the RH film. internal heavy rare-earth element RH is diffused into, but improves the coercivity H cJ lowers the remanence B r.
- a film of heavy rare earth element RH is formed on the surface of the sintered magnet body so that the heavy rare earth element RH flying on the surface of the magnet body can quickly penetrate into the sintered magnet body by grain boundary diffusion. There is no.
- the main phase inside the heavy rare-earth element RH in the grain is less likely to diffuse, suppressing reduction of the remanence B r, to effectively improve the coercive force H cJ Is possible.
- the contact portion between the RH diffusion source and the sintered magnet body is moved, while vaporizing (sublimating) the heavy rare earth element RH and By performing the supply by direct contact and the diffusion to the sintered magnet body at the same time, the time for placing the RH diffusion source and the sintered magnet body in a predetermined position becomes unnecessary.
- the heavy rare earth substitution layer can be formed on the main phase outer shell not only in the region close to the surface of the sintered magnet body but also in the region deep from the surface of the sintered magnet body.
- the heavy rare earth element RH it is not always necessary to add the heavy rare earth element RH to the RTB-based sintered magnet body before the RH diffusion treatment. That is, a known RTB-based sintered magnet body containing light rare earth element RL (at least one of Nd and Pr) as rare earth element R is prepared, and heavy rare earth element RH is diffused from the surface into the magnet. To do.
- the heavy rare earth element RH can be efficiently supplied also to the outer shell portion of the main phase located inside the sintered magnet body.
- the present invention is applied to the RTB-based sintered magnet to which the heavy rare earth element RH is added at the raw material alloy stage or the RTB-based sintered magnet body stage before the RH diffusion treatment. It may be applied.
- an RTB-based sintered magnet body to be diffused of heavy rare earth element RH is prepared.
- This sintered magnet body has the following composition.
- Rare earth element R 12 to 17 atomic% B (part of B may be substituted with C): 5 to 8 atomic%
- Additive element M selected from the group consisting of Al, Ti, V, Cr, Mn, Ni, Cu, Zn, Ga, Zr, Nb, Mo, Ag, In, Sn, Hf, Ta, W, Pb, and Bi At least one): 0 to 2 atomic% T (which is a transition metal mainly containing Fe and may contain Co) and inevitable impurities: the balance
- the rare earth element R is at least one element mainly selected from the light rare earth elements RL. It may contain a heavy rare earth element.
- the heavy rare earth element preferably contains at least one of Dy and Tb.
- the RTB-based sintered magnet body having the above composition is manufactured by an arbitrary manufacturing method, and is preferably manufactured by, for example, the following manufacturing method.
- raw materials are blended so as to have a predetermined composition and melted by high-frequency melting in, for example, an argon atmosphere to form a molten material alloy.
- a molten material alloy is melted by high-frequency melting in, for example, an argon atmosphere.
- it is rapidly cooled by a single roll method to obtain, for example, a flake-shaped alloy ingot having a thickness of about 0.3 mm.
- the alloy slab thus produced is pulverized into flakes having a size of 1 to 10 mm, for example, before the next hydrogen pulverization.
- the manufacturing method of the raw material alloy by a strip cast method is disclosed by US Patent 5,383,978 specification, for example.
- a raw material alloy made of a rare earth alloy is pulverized to a size of about 0.1 mm to several mm, and the average particle diameter becomes 500 ⁇ m or less.
- the embrittled raw material alloy is preferably crushed more finely and cooled. In the case where the raw material is taken out in a relatively high temperature state, the cooling process time may be relatively long.
- the coarsely pulverized powder is finely pulverized using a jet mill pulverizer.
- a cyclone classifier is connected to the jet mill crusher used in the present embodiment.
- the jet mill pulverizer is supplied with the rare earth alloy (coarse pulverized powder) coarsely pulverized in the coarse pulverization step, and pulverizes in the pulverizer.
- the powder pulverized in the pulverizer is collected in a collection tank through a cyclone classifier.
- a fine powder of about 0.1 to 20 ⁇ m (typically 3 to 5 ⁇ m) can be obtained.
- the pulverizer used for such fine pulverization is not limited to a jet mill, and may be an attritor or a ball mill. In grinding, a lubricant such as zinc stearate may be used as a grinding aid.
- [Sintering process] A step of holding the powder compact at a temperature in the range of 650 to 1000 ° C. for 10 to 240 minutes, and further sintering at a temperature higher than the holding temperature (for example, 1000 to 1200 ° C.). It is preferable to sequentially perform the proceeding steps. During sintering, particularly when a liquid phase is generated (when the temperature is in the range of 650 to 1000 ° C.), the R-rich phase in the grain boundary phase begins to melt and a liquid phase is formed. Then, sintering progresses and a sintered magnet body is formed.
- the vapor deposition diffusion treatment can be performed even when the surface of the sintered magnet body is oxidized, after the sintering process, an aging treatment (400 ° C. to 700 ° C.) or a grinding process for adjusting dimensions may be performed. good.
- the RH diffusion source that is, a heavy rare earth element RH composed of at least one of Dy and Tb, or an alloy containing them, is not particularly limited in shape and size such as a block shape or a small piece shape. In the case of an alloy, an alloy containing 20 atomic% or more of the heavy rare earth element RH is preferable.
- the RH diffusion source is selected from the group consisting of Fe, Nd, Pr, La, Ce, Gd, Zn, Sn, Al, Cu, Zr and Co in addition to Dy and Tb as long as the effects of the present invention are not impaired. Further, at least one alloy may be contained. Furthermore, at least one selected from the group consisting of Ti, V, Cr, Mn, Ni, Ga, Nb, Mo, Ag, In, Hf, Ta, W, Pb, Si, and Bi may be included. .
- a curved surface is formed on the surface of the RH diffusion source from the viewpoint that the contact point easily moves quickly due to rotation or vibration of the processing chamber.
- a preferable shape of the RH diffusion source are, for example, a spherical shape, an elliptical spherical shape, and a cylindrical shape, and may be a powder shape such as chips. However, in the case of powder, it is not preferable that there are many powders having a particle size of 200 ⁇ m or less because welding tends to occur.
- the RH diffusion source is typically formed from Dy metal or Tb metal, but may be an alloy containing other elements.
- the size of the RH diffusion source may be smaller or larger than the sintered magnet body. However, it is preferable that the size of the processing chamber be easy to move according to the rotation, swing, and vibration of the processing chamber.
- a stirring auxiliary member into the processing chamber in addition to the RTB-based sintered magnet body and the RH diffusion source.
- the stirring auxiliary member promotes contact between the RH diffusion source and the RTB-based sintered magnet body, and the heavy rare earth element RH adhering to the stirring auxiliary member is indirectly supplied to the RTB-based sintered magnet body.
- the stirring assisting member also has a role of preventing chipping due to contact between the RTB-based sintered magnet bodies or between the RTB-based sintered magnet body and the RH diffusion source in the processing chamber.
- the stirrer auxiliary member has a shape that can easily move in the processing chamber, and the stirrer assisting member is mixed with the RTB-based sintered magnet body and the RH diffusion source to rotate, swing, and vibrate the processing chamber.
- shapes that are easy to move include spherical shapes, elliptical shapes, and cylindrical shapes having a diameter of several hundred ⁇ m to several tens of mm.
- the agitation auxiliary member may be formed of a material that has a specific gravity substantially equal to that of the sintered magnet body and hardly reacts even if it contacts the RTB-based sintered magnet body and the RH diffusion source during the RH diffusion treatment.
- the stirring auxiliary member can be suitably formed from ceramics of zirconia, silicon nitride, silicon carbide and boron nitride, or a mixture thereof. It can also be formed from elements of the genus including Mo, W, Nb, Ta, Hf, Zr, or mixtures thereof.
- the stirring assisting member can be put into the processing chamber before or during the RH diffusion process.
- the RTB-based sintered magnet body 1 and the RH diffusion source 2 are placed inside a stainless steel cylinder 3.
- the cylinder 3 functions as a “processing chamber”.
- the material of the cylinder 3 is not limited to stainless steel, but may be any material that has heat resistance that can withstand temperatures of 500 to 850 ° C. and does not easily react with the RTB-based sintered magnet body 1 and the RH diffusion source 2. Is optional. For example, Nb, Mo, W, and alloys thereof may be used.
- the tube 3 is provided with a lid 5 that can be opened and closed or removed. Further, a protrusion can be provided on the inner wall of the cylinder 3 so that the RH diffusion source and the sintered magnet body can efficiently move and contact.
- the cross-sectional shape perpendicular to the major axis direction of the cylinder 3 is not limited to a circle, and may be an ellipse, a polygon, or other shapes.
- the cylinder 3 in the state shown in FIG. 1 is connected to an exhaust device 6 such as a pump by a joint. By the action of the exhaust device 6, the inside of the cylinder 3 can be depressurized or pressurized while being shielded from the atmosphere (sealed state).
- An inert gas such as Ar can be introduced into the cylinder 3 from a gas cylinder (not shown).
- the cylinder 3 is heated by a heater 4 disposed on the outer periphery thereof. By heating the cylinder 3, the RTB-based sintered magnet body 1 and the RH diffusion source 2 housed therein are also heated.
- the cylinder 3 is supported so as to be rotatable around the central axis, and can be rotated by the variable motor 7 during heating by the heater 4.
- the peripheral speed of the inner wall surface of the cylinder 3 can be set to 0.01 m or more so that the RTB-based sintered magnet body 1 and the RH diffusion source 2 are not welded. It is preferable to set it to 0.5 m or less per second so that the RTB-based sintered magnet bodies in the cylinder are vigorously contacted and not chipped by rotation.
- the cylinder 3 is rotating, but in the present invention, the RTB-based sintered magnet body 1 and the RH diffusion source 2 are RT-in the cylinder 3 so that they are not welded during the RH diffusion process. If the B-based sintered magnet body and the RH diffusion source are relatively movable and contactable, the cylinder 3 may be oscillated or oscillated rather than rotated, You may perform several operation
- another container in which the RTB-based sintered magnet body 1 and the RH diffusion source 2 are charged in advance may be placed inside the cylinder 3.
- the number of other containers is not limited to one but may be plural.
- the joint and the lid 5 are removed from the cylinder 3, and the inside of the cylinder 3 is opened.
- the joint and the lid 5 are attached to the cylinder 3 again.
- the inside of the cylinder 3 is evacuated by the exhaust device 6.
- the joint is removed. Thereafter, heating by the heater 4 is performed while the cylinder 3 is rotated by the motor 7.
- the inside of the cylinder 3 during the heat treatment is in an inert atmosphere.
- the “inert atmosphere” in this specification includes a vacuum or an inert gas.
- the “inert gas” is a rare gas such as argon (Ar), but may be a gas that does not chemically react between the RTB-based sintered magnet body 1 and the RH diffusion source 2.
- it can be included in an “inert gas”.
- the pressure of the inert gas is preferably reduced so as to show a value lower than the atmospheric pressure.
- the diffusion amount of the heavy rare earth element RH can be increased because the RH diffusion source and the sintered magnet body are close to or in contact with each other, it is sufficient that the atmospheric gas pressure in the cylinder 3 is 1 kPa or less. It is. Further, the correlation between the degree of vacuum and the amount of RH diffusion is relatively small, and even if the degree of vacuum is further increased, the amount of diffusion of the heavy rare earth element RH (degree of improvement in coercive force) is not greatly affected. The amount of diffusion is more sensitive to the temperature of the RTB-based sintered magnet body than the atmospheric pressure.
- the RH diffusion source 2 containing the heavy rare earth element RH and the RTB-based sintered magnet body 1 are heated while being rotated together, whereby the heavy rare earth element RH is removed from the RH diffusion source. While being supplied to the surface of the RTB-based sintered magnet body.
- the temperature of the RH diffusion source and the RTB-based sintered magnet body is maintained within a range of 500 ° C. or higher and 850 ° C. or lower.
- the temperature range is that the RTB-based sintered magnet body and the RH diffusion source move and contact with each other in the processing chamber while the heavy rare earth element RH has an internal structure of the RTB-based sintered magnet body. This is a preferable temperature range in which it diffuses through the grain boundary phase and diffusion into the RTB-based sintered magnet body is efficiently performed.
- the holding time depends on the ratio of the amount of the sintered magnet body and the RH diffusion source charged when performing the RH diffusion treatment process, the shape of the sintered magnet body that performs the RH diffusion treatment, the shape of the RH diffusion source, and the RH diffusion treatment. It is determined in consideration of the amount of heavy rare earth element RH (diffusion amount) to be diffused into the sintered magnet body.
- the time for the RH diffusion treatment step is 10 minutes to 72 hours. Preferably it is 1 to 12 hours.
- the temperature of the RH diffusion source and the RTB-based sintered magnet body is maintained in the range of 700 ° C. or higher and 850 ° C. or lower.
- the processing temperature exceeds 850 ° C.
- the processing temperature exceeds 850 ° C.
- the supply amount of heavy rare earth element RH becomes excessive, and a coating mainly composed of heavy rare earth element RH is easily generated on the surface of the sintered magnet body.
- the film of the heavy rare-earth element RH is produced by diffusion treatment to the internal magnet, the main phase crystal near the surface will be diffused heavy rare-earth element RH into the inside the main phase, decreases remanence B r of the magnet Therefore, it is not preferable.
- the treatment temperature is lower than 700 ° C., no loss of remanence B r, albeit the effect of improving the coercivity H cJ, not preferable from the productivity because it may take a long time to process.
- the pressure of the atmospheric gas during the RH diffusion step can be performed at atmospheric pressure or lower. It is preferable to carry out at 100 kPa or less. For example, it can be set within a range of 10 ⁇ 3 to 10 3 Pa.
- the RTB-based sintered magnet body 1 may be additionally subjected to heat treatment for the purpose of homogenizing the diffused heavy rare earth element RH.
- the heat treatment is preferably performed in the range of 700 ° C. or more and 1000 ° C. or less in a state where the heavy rare earth element RH is not supplied from the RH diffusion source 2 to the RTB-based sintered magnet body 1. More preferably, it is carried out at a temperature of 850 ° C. to 950 ° C.
- the heavy rare earth element RH can be diffused deeply from the surface side of the RTB-based sintered magnet body 1 to increase the coercive force of the entire magnet.
- the time for the additional heat treatment is, for example, 10 minutes to 72 hours. Preferably it is 1 to 12 hours.
- the atmospheric pressure of the heat treatment furnace for performing the additional heat treatment is equal to or lower than the atmospheric pressure. Preferred is 100 kPa or less.
- an aging treatment (400 ° C. to 700 ° C.) is performed as necessary, but when an additional heat treatment is performed, the aging treatment is preferably performed after that.
- the additional heat treatment and the aging treatment may be performed in the same processing chamber.
- the time for aging treatment is, for example, 10 minutes to 72 hours. Preferably it is 1 to 12 hours.
- the atmospheric pressure of the heat treatment furnace for performing the aging treatment is not more than atmospheric pressure. Preferred is 100 kPa or less.
- a magnet body was produced. This was machined to obtain a cubic sintered magnet body having a size of 7.4 mm ⁇ 7.4 mm ⁇ 7.4 mm.
- the coercivity H cJ in properties after aging treatment 500 ° C.
- residual flux density B r was 1.43T .
- RH diffusion processing was performed using the apparatus shown in FIG. 1 under the conditions shown in Table 1 below.
- Each surface of the magnet body after the diffusion treatment was ground by 0.2 mm and processed into a 7.0 mm ⁇ 7.0 mm ⁇ 7.0 mm cube, and then the magnet characteristics were evaluated.
- FIG. 2 is a graph showing a change (heat pattern) in the processing chamber temperature after the start of heating.
- evacuation is performed while the temperature is raised by the heater.
- the temperature rising rate is about 10 ° C./min.
- the temperature is maintained at about 600 ° C. until the pressure in the process chamber reaches the desired level.
- rotation of the processing chamber is started.
- the temperature is raised until the diffusion treatment temperature (700 ° C. or higher and 850 ° C. or lower: 800 ° C., for example) is reached.
- the temperature rising rate is about 3 ° C./min.
- the temperature is maintained for a predetermined time (2 hours in this experimental example).
- the heat pattern that can be executed by the diffusion processing of the present invention is not limited to the example shown in FIG. 2, and various other patterns can be adopted. Further, evacuation may be performed until the diffusion treatment is completed and the sintered magnet body is sufficiently cooled.
- the “RH diffusion source” column shows the shape and size of the RH diffusion source used in the diffusion treatment process.
- the rotation speed column
- the rotation speed of the cylinder 3 shown in FIG. 1 is shown.
- the peripheral speed column
- the peripheral speed of the inner wall surface of the processing chamber (cylinder 3 having a diameter of 100 mm) shown in FIG. 1 is shown.
- the temperature of the processing chamber held for 2 hours during the diffusion processing is shown.
- “Additional heat treatment” “None” is described for samples in which the additional heat treatment was not performed on the sintered magnet body taken out from the apparatus of FIG. The temperature of the heat treatment is described. The time for the additional heat treatment is 2 hours.
- the “ ⁇ Dy” column shows the difference (increase) in the Dy content (unit: mass%) of the sintered magnet body before and after the diffusion treatment
- the “H cJ ” column shows that after the diffusion treatment (additional)
- the sample subjected to the heat treatment has a coercive force H cJ after the additional heat treatment).
- the value of ⁇ Dy is the difference between the Dy amount (mass%) obtained by analyzing the entire magnet after the characteristic evaluation by the ICP method and the Dy amount (mass%) obtained by ICP analysis of the magnet before the RH diffusion treatment. Obtained by seeking.
- FIG. 3 is a graph showing the relationship between the increase amount ⁇ H cJ of the coercive force H cJ and the diffusion temperature.
- the vertical axis of the graph is the amount of increase in coercive force H cJ
- the horizontal axis is the diffusion temperature.
- the effect of increasing the coercive force can be confirmed in the temperature range of 700 ° C. to 850 ° C. It can also be seen that if the additional heat treatment is performed, the coercive force can be further increased as compared with the case where the additional heat treatment is not performed. This result shows that it is preferable to perform additional heat processing.
- FIG. 4 is a graph showing the relationship between the amount of increase in coercive force H cJ and the amount of increase in Dy content (mass%) due to diffusion treatment.
- the vertical axis of the graph is the amount of increase in coercive force H cJ
- the horizontal axis is the increase in Dy content ⁇ Dy.
- the coercive force H cJ increases with the increase in the Dy content.
- the RH diffusion source and the sintered magnet body are brought into contact with each other in the processing chamber and the contact point is fixed. If this is not done, it is possible to effectively introduce Dy into the sintered magnet while avoiding welding, thereby improving the magnet characteristics.
- the peripheral speed of the inner wall surface of the processing chamber during the diffusion process can be set to 0.01 m / s or more, for example.
- the rotation speed is slow, the movement of the contact portion between the sintered magnet body and the RH diffusion source is slow, and welding is likely to occur. For this reason, it is preferable to increase a rotational speed, so that diffusion temperature is high.
- a preferable rotation speed varies depending not only on the diffusion temperature but also on the shape and size of the RH diffusion source.
- the temperature of the processing chamber during the diffusion treatment changed as shown in FIG.
- the meanings of the columns in Table 2 are the same as those in Table 1.
- the shape and size of the RH diffusion source used in the diffusion treatment process are shown.
- the rotational speed (rpm) of the cylinder 3 in FIG. 1 and the peripheral speed (m / s) of the inner wall surface of the processing chamber (cylinder 3 having a diameter of 100 mm) shown in FIG. In the column of “Diffusion temperature”, the temperature of the processing chamber held for 2 hours during the diffusion processing is shown.
- samples 18 to 25 diffusion treatment was performed using a block-shaped Tb having a thickness of 10 mm ⁇ length 10 mm ⁇ width 10 mm to thickness 5 mm ⁇ length 5 mm ⁇ width 5 mm as an RH diffusion source.
- samples 18 to 23 of the present invention from Table 2 almost no decrease in remanence B r as compared with before the RH diffusion process, it can be seen that the coercive force H cJ is improved.
- FIG. 5 is a graph showing the relationship between the increase amount of the coercive force H cJ and the diffusion temperature.
- the vertical axis of the graph is the amount of increase in coercive force H cJ
- the horizontal axis is the diffusion temperature.
- the effect of increasing the coercive force can be confirmed in the temperature range of 800 ° C. to 820 ° C. It can also be seen that if the additional heat treatment is performed, the coercive force can be further increased as compared with the case where the additional heat treatment is not performed.
- the RH diffusion source and the sintered magnet body are brought into contact with each other in the processing chamber and the contact point is fixed. If this is not done, it is possible to effectively introduce Tb into the sintered magnet body while avoiding welding, thereby improving the magnet characteristics.
- Example 3 Except for the conditions shown in Table 3 below, the sintered magnet body produced in Experimental Example 1 is subjected to RH diffusion treatment under the same conditions as in Experimental Example 1. Each surface of the sintered magnet body after the diffusion treatment was ground by 0.2 mm and processed into a 7.0 mm ⁇ 7.0 mm ⁇ 7.0 mm cube, and the magnet characteristics were evaluated with a BH tracer. , RH diffusion temperature is 500 ° C., almost no decrease in remanence B r as compared with before the RH diffusion process even in samples 26 and 27 is 600 ° C., it can be seen that the coercive force H cJ is improved .
- the cylinder volume is 128000 mm 3
- the weight of the RTB-based sintered magnet (or the number of pieces charged) is 50 g (5 pieces)
- the weight of the RH diffusion source is 50 g.
- An RH diffusion source having a diameter of 3 mm or less is used. No aging treatment after diffusion is performed.
- the processing chamber during diffusion processing is evacuated while the temperature is raised by the heater.
- the temperature rising rate is about 10 ° C./min.
- the temperature is maintained at about 600 ° C. until the pressure in the process chamber reaches the desired level.
- rotation of the processing chamber is started.
- the temperature is raised until the diffusion treatment temperature is reached.
- the temperature rising rate is about 10 ° C./min.
- After reaching the diffusion treatment temperature hold at that temperature.
- heating by the heater is stopped and the temperature is lowered to about room temperature.
- the sintered magnet body taken out from the apparatus of FIG. 1 is put into another heat treatment furnace, and additional heat treatment (700 ° C. to 900 ° C., 4 to 6 hours) is performed at the same atmospheric pressure as in the diffusion treatment.
- An aging treatment after diffusion (450 ° C. to 550 ° C., 3 to 5 hours) is performed.
- the processing temperature and time for the additional heat treatment and aging treatment are set in consideration of the amount of the RTB-based sintered magnet body and the RH diffusion source input, the composition of the RH diffusion source, the RH diffusion temperature, and the like. ing.
- Table 5 Sample 44 and Table 4 sample 28 is better to put a zirconia ball having a diameter of 5 mm, a short time it can be seen that H cJ can be increased. This is because the stirring auxiliary member made of zirconia spheres promotes the contact between the RH diffusion source and the sintered magnet body and indirectly supplies the heavy rare earth element RH attached to the stirring auxiliary member to the sintered magnet body. Think of things. Occurrence of chipping is also suppressed as compared with samples 28, 29, 34, 35, 39 to 43.
- the coercivity H cJ is 1000 kA / m in properties after aging treatment (400 ° C.), the residual magnetic flux density B r is It was 1.42T.
- the cylinder volume is 128000 mm 3
- the weight of the RTB-based sintered magnet (or the number of pieces charged) is 50 g (5 pieces)
- the weight of the RH diffusion source is 50 g.
- a spherical RH diffusion source having a diameter of 3 mm or less is used.
- the diffusion assisting member performs RH diffusion treatment using a zirconia sphere weight (50 g) having a diameter of 5 mm as a stirring assisting member.
- the processing chamber during diffusion processing is evacuated while the temperature is raised by the heater.
- the temperature rising rate is about 10 ° C./min.
- the temperature is maintained at about 600 ° C. until the pressure in the process chamber reaches the desired level.
- rotation of the processing chamber is started.
- the temperature is raised until the diffusion treatment temperature is reached.
- the temperature rising rate is about 10 ° C./min.
- After reaching the diffusion treatment temperature hold at that temperature.
- heating by the heater is stopped and the temperature is lowered to about room temperature.
- the sintered magnet body taken out from the apparatus of FIG. 1 is put into another heat treatment furnace, and additional heat treatment (700 ° C. to 900 ° C., 4 to 6 hours) is performed at the same atmospheric pressure as during the diffusion treatment.
- the processing temperature and time for the additional heat treatment and aging treatment are set in consideration of the amount of the RTB-based sintered magnet body and the RH diffusion source input, the composition of the RH diffusion source, the RH diffusion temperature, and the like. ing.
- an RTB-based sintered magnet having a high residual magnetic flux density and a high coercive force can be produced as a whole magnet. It is suitable for various motors such as a motor for mounting on a hybrid vehicle exposed to high temperatures, home appliances, and the like.
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Abstract
Description
まず、本発明では、重希土類元素RHの拡散の対象とするR-T-B系焼結磁石体を用意する。この焼結磁石体は、以下の組成からなる。
希土類元素R:12~17原子%
B(Bの一部はCで置換されていてもよい):5~8原子%
添加元素M(Al、Ti、V、Cr、Mn、Ni、Cu、Zn、Ga、Zr、Nb、Mo、Ag、In、Sn、Hf、Ta、W、Pb、およびBiからなる群から選択された少なくとも1種):0~2原子%
T(Feを主とする遷移金属であって、Coを含んでもよい)および不可避不純物:残部
ここで、希土類元素Rは、主として軽希土類元素RLから選択される少なくとも1種の元素であるが、重希土類元素を含有していてもよい。なお、重希土類元素は、DyおよびTbの少なくとも一方を含むことが好ましい。
まず、最終的に上記組成を有する焼結磁石体となるように組成が調整された合金を用意する。この合金は、原料合金の溶湯を例えばストリップキャスト法によって急冷して好適に作製され得る。以下、ストリップキャスト法による急冷凝固合金の作製を説明する。
上記のフレーク状に粗く粉砕された合金鋳片を水素炉の内部へ収容する。次に、水素炉の内部で水素脆化処理(以下、「水素粉砕処理」と称する場合がある)工程を行う。水素粉砕後の粗粉砕合金粉末を水素炉から取り出す際、粗粉砕粉が大気と接触しないように、不活性雰囲気下で取り出し動作を実行することが好ましい。そうすれば、粗粉砕粉が酸化・発熱することが防止され、磁石の磁気特性の低下が抑制できるからである。
次に、粗粉砕粉に対してジェットミル粉砕装置を用いて微粉砕を実行する。本実施形態で使用するジェットミル粉砕装置にはサイクロン分級機が接続されている。ジェットミル粉砕装置は、粗粉砕工程で粗く粉砕された希土類合金(粗粉砕粉)の供給を受け、粉砕機内で粉砕する。粉砕機内で粉砕された粉末はサイクロン分級機を経て回収タンクに集められる。こうして、0.1~20μm程度(典型的には3~5μm)の微粉末を得ることができる。このような微粉砕に用いる粉砕装置は、ジェットミルに限定されず、アトライタやボールミルであってもよい。粉砕に際して、ステアリン酸亜鉛などの潤滑剤を粉砕助剤として用いてもよい。
本実施形態では、上記方法で作製された磁性粉末に対し、例えばロッキングミキサー内で潤滑剤を例えば0.3質量%添加・混合し、潤滑剤で合金粉末粒子の表面を被覆する。次に、上述の方法で作製した磁性粉末を公知のプレス装置を用いて配向磁界中で成形する。印加する磁界の強度は、例えば0.8~1.5MA/mである。また、成形圧力は、成形体のグリーン密度が例えば4~4.5g/cm3程度になるように設定される。
上記の粉末成形体に対して、650~1000℃の範囲内の温度で10~240分間保持する工程と、その後、上記の保持温度よりも高い温度(例えば1000~1200℃)で焼結を更に進める工程とを順次行なうことが好ましい。焼結時、特に液相が生成されるとき(温度が650~1000℃の範囲内にあるとき)、粒界相中のRリッチ相が融け始め、液相が形成される。その後、焼結が進行し、焼結磁石体が形成される。焼結磁石体の表面が酸化された状態でも蒸着拡散処理を施すことができるため、焼結工程の後、時効処理(400℃~700℃)や、寸法調整のための研削加工を行っても良い。
RH拡散源、すなわち、DyおよびTbの少なくとも1種からなる重希土類元素RHまたはそれらを含有する合金で、ブロック状、小片状など形状・大きさは特に限定されない。合金の場合は、重希土類元素RHを20原子%以上含有する合金であるのが好ましい。RH拡散源は、本発明の効果を損なわない限りにおいて、Dy、Tb以外に、Fe、Nd、Pr、La、Ce、Gd、Zn、Sn、Al、Cu、ZrおよびCoからなる群から選択された少なくとも1種の合金を含有してもよい。さらに、Ti、V、Cr、Mn、Ni、Ga、Nb、Mo、Ag、In、Hf、Ta、W、Pb、Si、およびBiからなる群から選択された少なくとも1種を含んでいてもよい。
図1を参照しながら、本発明による拡散処理工程の好ましい例を説明する。
また、必要に応じて時効処理(400℃から700℃)を行うが、追加熱処理を行う場合は、時効処理はその後に行うことが好ましい。追加熱処理と時効処理とは、同じ処理室内で行ってもよい。時効処理の時間は例えば10分から72時間である。好ましくは1時間から12時間である。ここで、時効処理を行なう熱処理炉の雰囲気圧力は、大気圧以下である。好ましいのは100kPa以下である。
まず、組成比Nd=29.5、Dy=0.5、B=1.0、Co=0.9、Al=0.1、Cu=0.1、残部:Fe(質量%)の焼結磁石体を作製した。これを機械加工することにより、7.4mm×7.4mm×7.4mmの立方体の焼結磁石体を得た。作製した焼結磁石体の磁気特性をB-Hトレーサによって測定したところ、時効処理(500℃)後の特性で保磁力HcJは954kA/m、残留磁束密度Brは1.43Tであった。
まず、組成比Nd=30.0、B=1.0、Co=0.9、Al=0.1、Cu=0.1、残部:Fe(質量%)の焼結磁石体を作製した。これを機械加工することにより、7.4mm×7.4mm×7.4mmの立方体の焼結磁石体を得た。作製した焼結磁石体の時効処理(500℃)後の磁気特性をB-Hトレーサによって測定したところ、保磁力HcJは930kA/m、残留磁束密度Brは1.45Tであった。
以下の表3に示す各条件を除き、実験例1にて作製した焼結磁石体を実験例1と同じ条件でRH拡散処理を実行する。拡散処理後における焼結磁石体の各面を0.2mmずつ研削し、7.0mm×7.0mm×7.0mmの立方体に加工した後、その磁石特性をB-Hトレーサーにて評価したところ、RH拡散温度が500℃、600℃であるサンプル26、27においてもRH拡散処理をする前と比べて残留磁束密度Brの低下がほとんどなく、保磁力HcJが向上しているのがわかる。
まず、組成比Nd=30.0、Dy=0.5、B=1.0、Co=0.9、Al=0.1、Cu=0.1、残部:Fe(質量%)のR-T-B系焼結磁石体を作製した。これを機械加工することにより、7.4mm×7.4mm×7.4mmの立方体のR-T-B系焼結磁石体を得た。作製したR-T-B系焼結磁石体の磁気特性をB-Hトレーサによって測定したところ、時効処理(400℃)後の特性で保磁力HcJは1000kA/m、残留磁束密度Brは1.42Tであった。
次に、直径5mmのジルコニア球重量(50g)を攪拌補助部材として使用してRH拡散処理を行った以外は、実験例4と同じ条件でRH拡散処理を行う。その結果を、表5に示す。表5に示されるように、サンプル44、45、47、49、50、52から56では、サンプル28、29、34、35、39から43に比べて、RH拡散処理時間が半分になったにも関わらず、ほぼ同等の特性が得られることがわかる。サンプル46、47から、雰囲気圧力が高くとも本発明の効果が得られることがわかる。表5のサンプル44と表4のサンプル28から、直径5mmのジルコニア球を投入した方が、短時間でHcJが向上することがわかる。これは、ジルコニア球からなる攪拌補助部材が、RH拡散源と焼結磁石体との接触を促進し、かつ攪拌補助部材に付着した重希土類元素RHを焼結磁石体へ間接に供給する効果によるものと考える。欠けの発生もサンプル28、29、34、35、39から43と比べ抑制されている。
まず、実施例4と同じく組成比Nd=30.0、Dy=0.5、B=1.0、Co=0.9、Al=0.1、Cu=0.1、残部:Fe(質量%)のR-T-B系焼結磁石体を作製した。これを機械加工することにより、7.4mm×7.4mm×7.4mmの立方体のR-T-B系焼結磁石体を得た。作製したR-T-B系焼結磁石体の磁気特性をB-Hトレーサによって測定したところ、時効処理(400℃)後の特性で保磁力HcJは1000kA/m、残留磁束密度Brは1.42Tであった。
2 RH拡散源
3 ステンレス製の筒(処理室)
4 ヒータ
5 蓋
6 排気装置
Claims (7)
- R-T-B系焼結磁石体を準備する工程と、
重希土類元素RH(DyおよびTbの少なくとも1種)の金属または合金からなるRH拡散源を準備する工程と、
前記R-T-B系焼結磁石体と前記RH拡散源とを相対的に移動可能かつ近接または接触可能に処理室内に装入する工程と、
前記R-T-B系焼結磁石体と前記RH拡散源とを前記処理室内にて連続的または断続的に移動させながら、500℃以上850℃以下の熱処理を10分以上行うRH拡散工程と、
を包含するR-T-B系焼結磁石の製造方法。 - 前記RH拡散工程は、前記処理室を回転させる工程を含む、請求項1に記載のR-T-B系焼結磁石の製造方法。
- 前記RH拡散工程において、前記処理室を周速度0.01m/s以上の速度で回転させる、請求項2に記載のR-T-B系焼結磁石の製造方法。
- 前記RH拡散工程における前記熱処理は、前記処理室の内部圧力を100kPa以下に調整して行う、請求項1から3のいずれかに記載のR-T-B系焼結磁石の製造方法。
- 前記RH拡散工程における前記熱処理は、前記処理室を加熱することにより、前記R-T-B系焼結磁石体および前記RH拡散源の両方を加熱して行う、請求項1から4のいずれかに記載のR-T-B系焼結磁石の製造方法。
- 前記RH拡散工程の前または途中において、攪拌補助部材を前記処理室内に投入する、請求項1から5のいずれかに記載のR-T-B系焼結磁石の製造方法。
- 請求項1から6に記載のR-T-B系焼結磁石の製造方法によって製造されたR-T-B系焼結磁石。
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JP2011522805A JP5510457B2 (ja) | 2009-07-15 | 2010-07-12 | R−t−b系焼結磁石の製造方法 |
US13/382,587 US9415444B2 (en) | 2009-07-15 | 2010-07-12 | Process for production of R-T-B based sintered magnets and R-T-B based sintered magnets |
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Also Published As
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JP5510457B2 (ja) | 2014-06-04 |
EP2455954A1 (en) | 2012-05-23 |
JPWO2011007758A1 (ja) | 2012-12-27 |
EP2455954B1 (en) | 2019-10-16 |
US20120112863A1 (en) | 2012-05-10 |
CN102473515A (zh) | 2012-05-23 |
EP2455954A4 (en) | 2016-08-31 |
US9415444B2 (en) | 2016-08-16 |
CN102473515B (zh) | 2016-06-15 |
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