EP2721618A1 - Aimant permanent à base de néodyme/fer/bore - Google Patents
Aimant permanent à base de néodyme/fer/boreInfo
- Publication number
- EP2721618A1 EP2721618A1 EP12800074.2A EP12800074A EP2721618A1 EP 2721618 A1 EP2721618 A1 EP 2721618A1 EP 12800074 A EP12800074 A EP 12800074A EP 2721618 A1 EP2721618 A1 EP 2721618A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- permanent magnet
- component
- boron
- iron
- combination
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Ceased
Links
Classifications
-
- 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
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
-
- 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
-
- 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
-
- 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
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
-
- 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
- C22C38/10—Ferrous alloys, e.g. steel alloys containing cobalt
-
- 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
- C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
-
- 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
- C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
-
- 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
-
- 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
- H01F41/0273—Imparting anisotropy
-
- 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
- B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
- B22F2998/10—Processes characterised by the sequence of their steps
-
- 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
Definitions
- the invention relates to a permanent magnet, more particularly to a sintered
- the invention also relates to an electric motor, a generator and an integrated electromotor comprising the permanent magnet.
- Electric motors with sintered neodymium/iron/boron-based permanent magnets are the vital components in electric vehicle and hybrid electric vehicle (EV/HEV). They show reduced copper losses, high power density, high efficiency, low rotor inertia, and other obvious advantages over induction motors.
- the sintered neodymium/iron/boron-based permanent magnets in EV/HEV motors need to have high enough remanence, coercivty and thermal stability, provide high enough magnetic field to secure a stable motor performance within the whole working temperature range (normally from -40 to 180°C).
- neodymium/iron/boron-based permanent magnets it is not so easy to retain high enough remanence and coercivity at a high temperature up to 180°C, although they have good magnetic properties at ambient temperature, the reason being that their remanence and coercivity will decay significantly as the temperature increases.
- neodymium/iron/boron-based permanent magnets a main challenge for the neodymium/iron/boron-based permanent magnets is how to achieve high enough remanence and coercivity at a temperature up to 180°C (which is especially important for EV/HEV permanent magnet motors).
- a conventional solution for this challenge is to add substantial quantities of heavy rare earth elements such as terbium (Tb) and dysprosium (Dy) to the permanent magnets.
- Tb and Dy have a function to increase coercivity and thermal stability of the neodymium/iron/boron-based permanent magnets.
- Coercivity is an important property of permanent magnets which measures the resistance of the magnets to becoming demagnetized, that is the magnitude of the applied demagnetizing field required to reduce the induction or magnetization of permanent magnets to zero after the magnets have been magnetized to saturation.
- Intrinsic coercivity of the magnets is the permanent magnets' inherent ability to resist demagnetization.
- a high intrinsic coercivity represents its great ability to withstand an external magnetic field.
- Thermal stability is the ability of the permanent magnets to resist the change of coercivity and remanence against increasing temperature.
- the remanence and coercivity of the current commercial magnets will decay at a respective rate of >0.12 /°C and >0.5 /°C as temperature increases from 20°C to 180°C.
- the industries have attempted to introduce high contents of heavy rare earth elements Tb and Dy into the magnets to reduce the impact of the temperature on the remanence and coercivity of the permanent magnets .
- US 2007/0137733 Al discloses a sytem of permanent magnet comprising rare earth material (>50wt.% Pr, 0-25wt.% Tb, 0-25wt.% Dy), Co and Ga with addition of Al, Cu, Cr, V, Nb and Zr.
- rare earth material >50wt.% Pr, 0-25wt.% Tb, 0-25wt.% Dy
- Co and Ga with addition of Al, Cu, Cr, V, Nb and Zr.
- the intrinsic coercivity of the magnet is less than 18.9 KOe
- Tb and no Dy the intrinsic coercivity is less than 2308KA/m
- the intrinsic coercivity is less than
- EP0680054B2 discloses a RE-Fe-B magnet comprising Dy (and no Tb), Co, C, O and Ag with addition of Al, Si, Sn, Zn, Nb, Mo, V, Cr, Zr, Hf, Ti and Mg, the magent having an intrinsic coercivity ranging from 748 to 1623KA/m.
- EP1014392B2 discloses a rare earth/iron/boron-based permanent magnet comprising rare earth elements (Nd, Pr, Dy, Tb and Hf), Co, C, N, and O with addition of Al, Cu, Zr and Cr, the magnet having an intrinsic coercivity up to 159KA/m.
- a neodymium/iron/boron- based permanent magnet comprising:
- component R 2 to 13 wt.% of component R, wherein component R is selected from Pr, Ce, Gd, or Y, or any combination thereof,
- component T 1.4 to 9 wt.% of component T, wherein component T is selected from Co, Cu, or Al, or any combination thereof,
- component M 0.1 to 0.6 wt.% of component M, wherein component M is selected from Zr, Ti, or Mo, or any combination thereof,
- the permanent magnet according to the invention has an intrinsic coercivity of 2040 to 2745KA/m at 20°C, and a temperature coefficient of intrinsic coercivity of 0.38 to 0.43%/°C.
- neodymium/iron/boron-based permanent magnet comprising the steps of:
- an alloy strip comprising 16 to 25 wt.% of Nd, 4 to 10 wt.% of Dy, 0 to 1.2 wt.% of Tb, 2 to 13 wt.% of component R, which is selected from Pr, Ce, Gd, or Y, or any combination thereof, 1.4 to 9 wt.% of component T, which is selected from Co, Cu, or Al, or any combination thereof, 0.1 to 0.6 wt.% of component M, which is selected from Zr, Ti, or Mo, or any combination thereof, 0.9 to 1.1 wt.% of B, and the balance of Fe;
- an electric motor, a generator, an integrated starter-generator and/or other integrated electromotors comprising the permanent magnet.
- Figure 1 schematically illustrates the flow chart of the method of manufacturing a neodymium/iron/boron-based permanent magnet according to the invention
- Figure 2 schematically illustrates different shapes of the sintered
- neodymium/iron/boron-based permanent magnet according to the invention.
- the invention provides a novel sintered neodymium/iron/boron-based permanent magnet, consisting of Fe, B, a limited amount of heavy rare earth element Dy and very little or no Tb, light rare earth elements Nd and Pr, a combination of Co, Zr, Cu, Al, Y, Mo, Ti, Ce and/or Gd, and inevitable impurity such as O.
- the magnet only contains a limited amount of Dy and very little or even no Tb, and yet has high coercivity and high thermal stability.
- the magnet does not contain Ga, Nb, Cr and Ag. More specifically, the invention relates to a sintered neodymium/iron/boron-based permanent magnet, comprising:
- component R 2 to 13 wt.% of component R, wherein component R is selected from Pr, Ce, Gd, or Y, or any combination thereof,
- component T 1.4 to 9 wt.% of component T, wherein component T is selected from Co, Cu, or Al, or any combination thereof,
- component M 0.1 to 0.6 wt.% of component M, wherein component M is selected from Zr, Ti, or Mo, or any combination thereof,
- the permanent magnet according to the invention has an intrinsic coercivity of 2040 to 2745KA/m at 20°C, and a temperature coefficient of intrinsic coercivity of 0.38 to 0.43%/°C.
- Dy may be present in an amount of 5 to 8 wt.%, and Tb may be present in an amount of 0 to 1 wt.%.
- Component R is preferably Pr, Ce, or Y, or any combination thereof, and may be present in an amount of 4 to 6 wt.%.
- Component T is preferably a combination of Co, Cu, and Al, and may be present in an amount of 1.5 to 4.0 wt.%.
- Component M is preferably Zr, and may be present in an amount of 0.15 to 0.4 wt.%.
- the components R, T, and M play an important role in improving the coercivity and thermal stability of the magnet.
- the presence of these components refines the magnet grains and homogenize the micro structure of the magnet, thereby significantly improving the intrinsic coercivity (compared to the permanent magnet described in US 2007/0137733A1, the intrinsic coercivity at ambient temperature increases by about 64%).
- a method of manufacturing the sintered neodymium/iron/boron-based permanent magnet according to the invention is illustrated as follows. Firstly, alloy strips having said composition are formed. Specifically, industrial pure raw materials (which all are metals or alloys) are smelted in the selected composition by vacuum- induction melting normally at 1380-1420°C (the vacuum degree being 5*10 ⁇ 2 to 7*10 ⁇ 2 Pa), and the raw materials can also be prealloys of master alloys made of the industrial pure raw materials. The smelter is then cast onto a spinning copper wheel which spins normally at 0.6- 3.5 m/s and cast into thin alloy strips having a thickness ranging from 0.1 to 1mm. The smelting process is performed under vacuum to avoid the oxidation of the metals and alloys.
- the alloy strips are processed into fine powders.
- the thin alloy strips are hydrogenated at 200KPa in a H 2 atmosphere, and then dehydogenated normally at 320°C and 580°C, then ground into fine powders by ball milling or jet milling in the protection of inert gas such as Ar and N 2 .
- the rotation speed is about 4800Hz.
- the formed fine powders have particle sizes ranging from ⁇ to ⁇ , with a mean particle size of about 3.5 ⁇ .
- the fine powders are then aligned in a magnetic field with an intensity of 2T and compacted into a green body at a pressure of 40MPa in the protective N 2 gas.
- particulate grains in the green body magnetically align to one direction, consequently the principal magnetic phase (RE) 2 Fei 4 B particles align along their easy axis.
- the green body is further pressed and compacted into a higher density body by cold isostatic pressing at a pressure of about 300MPa for a duration of about 30s.
- the higher density body is sintered at 900-1150°C for 1-10 hours to approximate its theoretical density.
- the sintered body is then heat treated at
- the sintering, heat treatment and aging processes are conducted under vacuum (the vacuum degree is, for example, 3*10 " Pa), and the subsequent cooling process is conducted in a protective inert gas atmosphere (for example, Ar).
- a protective inert gas atmosphere for example, Ar
- the sintered permanent magnet are then machined into different shapes (like the shapes as shown in Figure 2), applied with protective coatings and installed into an EV/HEV motor.
- the obtained sintered permanent magnet is analysed and measured. Its chemical composition is analysed by inductive coupling plasma emission spectrograph (ICP). Its magnetic properties are measured by B-H tracer and physical property measurement system (PPMS), and the temperature coefficients of coercivity and remanence are then calculated.
- ICP inductive coupling plasma emission spectrograph
- PPMS physical property measurement system
- the sintered neodymium/iron/boron-based permanent magnet according to the invention only contains a limited amount of Dy and very little or even no Tb, and yet has high coercivity and high thermal stability. It is a sintered neodymium/iron/boron-based permanent magnet having high coercivity, good thermal stability and a low production cost.
- Example 1 A sintered neodymium/iron/boron-based permanent magnet comprising 10 wt.% of Dy and no Tb
- Industrial pure raw materials (with a purity of 99%) were mixed in a ratio of 10wt.% Dy, 17.36wt.% Nd, 4.34wt.% Pr, 65.26wt.% Fe, 1.01 wt.% B, 1.0wt.% Co, 0.4wt.% Zr, 0.4wt.% Al and 0.23wt.% Cu, and introduced into a vacuum induction furnace (with a vacuum degree of 6*10 "2 Pa), and then smelted at 1420°C for 5 minutes. The smelter was cast onto a spinning copper wheel which spined at 1.7m/s and cast into thin alloy strips having a thickness of 0.5mm.
- the purpose of vacuum smelting and casting was to avoid the oxidation of the metals and alloys. Then, the thin alloy strips were hydrogenated at 200KPa in a H 2 atmosphere, and then dehydrogenated at 320°C and 580°C. After dehydrogenation, the alloy strips were ground into fine powders having particle sizes ranging from ⁇ to ⁇ with a mean particle size of 3.5 ⁇ by jet milling at a rotation speed of 4800Hz in the protection of N 2 gas. The fine powders were aligned in a magnetic field with an intensity of 2T in the protective N 2 gas, and compacted into a green body at a pressure of 40MPa.
- the principal magnetic phase (RE) 2 Fei 4 B particles aligned along their easy axis.
- the green body was then further pressed and compacted into a higher density body by cold isostatic pressing at a pressure of 300MPa for a duration of 30s.
- the higher density body was sintered at 1150°C for 2 hours, then heat treated at 900°C for 2 hours and aged at 650°C for 2 hours, to eventually form a sintered permanent magnet.
- the sintering, heat treatment and aging processes were conducted under vacuum (the vacuum degree was 3*10 " Pa), and the subsequent cooling process was conducted in a protective Ar gas atmosphere.
- the obtained sintered permanent magnet possesses the following good magnetic properties at 20°C: remanence (Br) of 1.12T, intrinsic coercivity (Hci) of 2745KA/m, energy product ((BH) max ) of 248KJ/m 3 ; at 180°C: remanence of 0.93T, intrinsic coercivity of 1050KA/m, energy product of 168KJ/m . Its temperature coefficients of remanence and intrinsic coercivty are respectively 0.11%/°C and 0.38%/°C within the temperature range of 20 to 180°C.
- Example 2 A sintered neodymium/iron/boron-based permanent magnet comprising 5.8wt.% of Dy and 0.8 wt.% of Tb.
- a sintered neodymium/iron/boron-based permanent magnet comprising 5.8wt.% Dy, 0.8wt.% Tb, 19.2 wt.% Nd, 4.8 wt.% Pr, 0.1 wt.% Ce, 0.2 wt.% Y, 65.52wt.% Fe, 0.98wt.% B, 2.0wt.% Co, 0.15wt.% Zr, 0.2wt.% Al and 0.25wt.% Cu was obtained.
- Example 3 A sintered neodymium/iron/boron-based permanent magnet comprising 6.0wt.% of Dy and 0.8 wt.% of Tb.
- a sintered neodymium/iron/boron-based permanent magnet comprising 6.0wt.% Dy, 0.8wt.% Tb, 19.2 wt.% Nd, 4.8 wt.% Pr, 0.2 wt.% Ce, 0.2 wt.% Y, 65.32wt.% Fe, 0.98wt.% B, 2.0wt.% Co, 0.15wt.% Zr, 0.2wt.% Al and 0.15 wt.% Cu was obtained.
- Example 4 A sintered neodymium/iron/boron-based permanent magnet comprising 6.0wt.% of Dy and 0.7wt.% of Tb.
- a sintered neodymium/iron/boron-based permanent magnet comprising 6.0wt.% Dy, 0.7wt.% Tb, 19.7 wt.% Nd, 4.92 wt.% Pr, 0.22 wt.% Ce, 0.2 wt.% Y, 63.26wt.% Fe, 0.97wt.% B, 3.0wt.% Co, 0.4wt.% Zr, 0.4wt.% Al and 0.23wt.% Cu was obtained.
- Example 5 A sintered neodymium/iron/boron-based permanent magnet comprising 6.0wt.% of Dy and 0.7wt.% of Tb.
- a sintered neodymium/iron/boron-based permanent magnet comprising 6.0wt.% Dy, 0.7wt.% Tb, 19.68 wt.% Nd, 4.92 wt.% Pr, 0.24 wt.% Ce, 0.2 wt.% Y, 65.14wt.% Fe, 0.97wt.% B, 1.0wt.% Co, 0.4wt.% Zr, 0.4wt.% Al and 0.35wt.% Cu was obtained.
- the permanent magnet according to the invention only contains a limited amount of Dy and very little or even no Tb, and yet has a high remanence and coercivity at a temperature up to 180°C, and the remanence and coercivity decay less as the temperature increases.
- the sintered neodymium/iron/boron-based permanent magnet according to the invention retains its good magnetic properties at a temperature up to 180°C, and therefore is capable of providing high enough magnetic field in the EV/HEV motors.
- the permanent magnet of the invention has been described in great detail with respect to its application in electric motors, it would be easily appreciated by one of ordinary skilled in the art that the magnent can also be applied in generators, due to similar working principles to electric motors, in order to overcome some or all technical disadvantages as mentioned above. Likewise, the permanent magnet of the invention can also be applied in integrated starter-generators for electric vehicles and hybrid electric vehicles, as well as other integrated electromotors.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Power Engineering (AREA)
- Crystallography & Structural Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Hard Magnetic Materials (AREA)
Abstract
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201110172170.4A CN102832003A (zh) | 2011-06-17 | 2011-06-17 | 一种钕/铁/硼基永磁体 |
PCT/CN2012/077023 WO2012171490A1 (fr) | 2011-06-17 | 2012-06-15 | Aimant permanent à base de néodyme/fer/bore |
Publications (2)
Publication Number | Publication Date |
---|---|
EP2721618A1 true EP2721618A1 (fr) | 2014-04-23 |
EP2721618A4 EP2721618A4 (fr) | 2015-07-08 |
Family
ID=47335092
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP12800074.2A Ceased EP2721618A4 (fr) | 2011-06-17 | 2012-06-15 | Aimant permanent à base de néodyme/fer/bore |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP2721618A4 (fr) |
CN (1) | CN102832003A (fr) |
WO (1) | WO2012171490A1 (fr) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR101543111B1 (ko) * | 2013-12-17 | 2015-08-10 | 현대자동차주식회사 | NdFeB 영구자석 및 그 제조방법 |
CN106964778A (zh) * | 2016-01-14 | 2017-07-21 | 罗伯特·博世有限公司 | 生产热变形磁体的方法和设备 |
JP2020095991A (ja) * | 2017-03-30 | 2020-06-18 | Tdk株式会社 | 焼結磁石及び回転機 |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5200001A (en) * | 1989-12-01 | 1993-04-06 | Sumitomo Special Metals Co., Ltd. | Permanent magnet |
JP3846835B2 (ja) * | 1998-10-14 | 2006-11-15 | 株式会社Neomax | R−t−b系焼結型永久磁石 |
KR100592471B1 (ko) * | 1998-10-14 | 2006-06-23 | 히다찌긴조꾸가부시끼가이사 | 알-티-비계 소결형 영구자석 |
US7199690B2 (en) * | 2003-03-27 | 2007-04-03 | Tdk Corporation | R-T-B system rare earth permanent magnet |
EP1749599B1 (fr) * | 2004-04-30 | 2015-09-09 | Hitachi Metals, Ltd. | Méthodes pour produire un alliage de matière première pour une poudre d'aimant rare sur la terre et aimant fritté |
US8182618B2 (en) * | 2005-12-02 | 2012-05-22 | Hitachi Metals, Ltd. | Rare earth sintered magnet and method for producing same |
CN101740190B (zh) * | 2008-11-26 | 2013-01-16 | 绵阳西磁磁电有限公司 | 一种高性价比高耐腐蚀性烧结钕铁硼磁体及制备方法 |
CN101615459B (zh) * | 2009-04-28 | 2011-11-23 | 中国科学院宁波材料技术与工程研究所 | 提高烧结钕铁硼永磁材料性能的方法 |
CN101877265A (zh) * | 2010-04-28 | 2010-11-03 | 天津天和磁材技术有限公司 | 一种高性能钕铁硼永磁材料的制造方法 |
CN101859639B (zh) * | 2010-07-06 | 2013-03-27 | 烟台正海磁性材料股份有限公司 | 一种梯度电阻R-Fe-B系磁体及其生产方法 |
-
2011
- 2011-06-17 CN CN201110172170.4A patent/CN102832003A/zh active Pending
-
2012
- 2012-06-15 EP EP12800074.2A patent/EP2721618A4/fr not_active Ceased
- 2012-06-15 WO PCT/CN2012/077023 patent/WO2012171490A1/fr unknown
Also Published As
Publication number | Publication date |
---|---|
WO2012171490A1 (fr) | 2012-12-20 |
CN102832003A (zh) | 2012-12-19 |
EP2721618A4 (fr) | 2015-07-08 |
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