WO2014204106A1 - Procédé de fabrication d'aimant permanent - Google Patents

Procédé de fabrication d'aimant permanent Download PDF

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Publication number
WO2014204106A1
WO2014204106A1 PCT/KR2014/004647 KR2014004647W WO2014204106A1 WO 2014204106 A1 WO2014204106 A1 WO 2014204106A1 KR 2014004647 W KR2014004647 W KR 2014004647W WO 2014204106 A1 WO2014204106 A1 WO 2014204106A1
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WO
WIPO (PCT)
Prior art keywords
heat treatment
content
permanent magnet
sintering
manufacturing
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PCT/KR2014/004647
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English (en)
Korean (ko)
Inventor
이성래
김태훈
장태석
Original Assignee
고려대학교 산학협력단
Priority date (The priority date 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 date listed.)
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Priority claimed from KR1020140030533A external-priority patent/KR101527324B1/ko
Application filed by 고려대학교 산학협력단 filed Critical 고려대학교 산학협력단
Publication of WO2014204106A1 publication Critical patent/WO2014204106A1/fr
Priority to US14/974,707 priority Critical patent/US20160104573A1/en

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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
    • H01F41/0273—Imparting anisotropy

Definitions

  • the present invention relates to a method of manufacturing a permanent magnet, and more particularly, to a method of manufacturing a Nd-Fe-B-based permanent magnet with improved coercivity while reducing the amount of Dy used.
  • Nd-Fe-B permanent magnets are increasingly used because of their excellent magnetic properties. Recently, in response to environmental problems, as the application of magnets is expanded to home appliances, industrial equipment, electric vehicles, and wind power generation, the performance of Nd-Fe-B magnets has been increasing.
  • the residual magnetic flux density and the magnitude of the coercive force can be given.
  • Increasing the residual magnetic flux density of the Nd-Fe-B-based sintered magnet is achieved by increasing the volume ratio of the Nd 2 Fe 14 B compound and improving the crystal orientation, and various processes have been improved so far.
  • various approaches such as miniaturization of grains, using alloys with increased Nd amounts, or adding effective elements.
  • Dy or Tb the most common method is Dy or Tb.
  • the composition alloy which substituted a part of Nd is used. By replacing Nd of the Nd 2 Fe 14 B compound with these elements, the anisotropic magnetic field of the compound increases and the coercive force also increases.
  • Patent Publication No. 10-2010-0097580 discloses a method for producing a sintered magnet through repeated heat treatment and a sintered magnet manufactured therefrom.
  • Korean Patent Publication No. 10-2010-0097580 does not disclose a method of improving the coercive force and reducing the Dy content in manufacturing a permanent magnet.
  • An object of the present invention is to provide a method for manufacturing a Nd-Fe-B-based permanent magnet with improved coercivity while reducing the amount of Dy used.
  • preparing a powder comprising Nd, Fe, B and Cu Preparing a molded body by forming a specific magnetic field on the powder; Sintering the molded body at a specific sintering temperature; And performing a heat treatment of the sintered molded body at a heat treatment temperature determined according to the content of Cu.
  • the Nd-Fe-B-based permanent magnet is manufactured by improving the coercivity while reducing the amount of Dy by varying the heat treatment temperature according to the Cu content as an additive. can do.
  • FIG. 1 is a flowchart illustrating a method of manufacturing a permanent magnet according to an embodiment of the present invention.
  • FIG. 2 is a view for explaining strip casting and hydrogen treatment in the method of manufacturing the permanent magnet shown in FIG. 1.
  • FIG. 4 is a view for explaining a process of manufacturing a molded body of the manufacturing method of the permanent magnet shown in FIG.
  • FIG. 5 is a view for explaining the sintering (sintering) process of the method of manufacturing a permanent magnet shown in FIG.
  • 6 to 7 are views for explaining the effect of the heat treatment after sintering in the method of manufacturing a permanent magnet according to an embodiment of the present invention.
  • FIG. 12 is a diagram for comparing the microstructure of the Nd-rich grain boundary phase with different Cu content.
  • 13 to 14 are diagrams for explaining the relationship between the Cu content and the heat treatment temperature.
  • FIG. 15 shows the coercive force and residual magnetization change with the primary heat treatment temperature of the sintered magnet containing 0.5 at.% Cu.
  • FIG. 16 is a view illustrating a microstructure of a specimen when the heat treatment is performed at the heat treatment temperature shown in FIG. 8 and the heat treatment temperature shown in FIG. 15.
  • FIG. 18 is a graph showing a change in magnetic properties according to the sintering temperature in accordance with an embodiment of the present invention.
  • 19 is a graph showing the coercive force change according to the first heat treatment temperature change in accordance with an embodiment of the present invention.
  • FIG. 1 is a flowchart illustrating a method of manufacturing a permanent magnet according to an embodiment of the present invention.
  • a powder containing Nd, Fe, B, and Cu may be manufactured (S110).
  • the powder manufacturing process may include processes such as strip casting, hydrotreating, and grinding.
  • FIG. 2 is a view for explaining strip casting and hydrogen treatment in the method of manufacturing the permanent magnet shown in FIG. 1.
  • the permanent magnet may be manufactured by varying the composition of other components depending on the content of Dy.
  • FIG. 3 is a view for explaining a process of grinding the master alloy of the manufacturing method of the permanent magnet shown in FIG.
  • the strip-cast master alloy shown in FIG. 2 may be ground using jet-milling. Due to the grinding process, a ferromagnetic powder having a single crystal can be produced.
  • the content of Cu relative to the powder may be preferably 0.01 to 0.8 weight ratio. When the content of Cu in the powder exceeds 0.8 weight ratio, the density becomes low, and when the content of Cu in the powder is less than 0.01 weight ratio, the effect of Cu addition is insignificant.
  • a molded body may be manufactured by forming a specific magnetic field on the powder (S120).
  • FIG. 4 is a view for explaining a process of manufacturing a molded body of the manufacturing method of the permanent magnet shown in FIG.
  • a green compact may be manufactured by applying pressure to the ferromagnetic powder while applying a specific magnetic field (for example, about 2.2T) to the powder.
  • the produced molded article has easy magnetization axes aligned in one direction.
  • the molded body When the molded body is manufactured, the molded body may be sintered (S130).
  • FIG. 5 is a view for explaining the sintering (sintering) process of the method of manufacturing a permanent magnet shown in FIG.
  • the molded body may be sintered for a predetermined time under a specific atmosphere.
  • the molded body may be sintered at 1070 ° C to 1040 ° C for 4 hours in a vacuum atmosphere.
  • the ideal sintering temperature and sintering time may vary depending on the composition and the atmosphere sintering furnace. Liquid phase sintering may be performed until densification is achieved by about 99%. Through the sintering process, an anisotropic magnet having a full density may be manufactured.
  • heat treatment may be performed (S140).
  • the heat treatment may be performed once, but may be performed a plurality of times to improve properties.
  • heat treatment may proceed three times to improve properties.
  • Ideal heat treatment conditions may vary depending on the composition and environment. Mainly, high temperature heat treatment and low temperature heat treatment can be divided into two processes.
  • the heat treatment may be performed by varying the temperature according to the content of Cu.
  • the heat treatment temperature determined according to the Cu content as described above, even if the amount of Dy (dysprosium) is reduced, the coercive force can be produced a permanent magnet.
  • the heat treatment when the heat treatment is performed a plurality of times, the heat treatment may be performed at a heat treatment temperature determined according to the content of Cu only for the first heat treatment.
  • 6 to 7 are views for explaining the effect of the heat treatment after sintering in the method of manufacturing a permanent magnet according to an embodiment of the present invention.
  • FIG. 6 shows a microstructure in which heat treatment is performed after sintering.
  • Post-sintering annealing is essential to improve the coercive force of Nd-Fe-B sintered magnets. That is, in order to reduce the Dy content, which is an expensive heavy rare earth element, heat treatment after sintering is one of very efficient methods.
  • the coercive force of the sintered magnet is greatly affected by the microstructure of the nonmagnetic Nd-rich triple point and grain boundaries. The heat treatment effect is as follows.
  • continuity of the Nd-rich grain boundary phase may be improved through heat treatment.
  • the coercive force is improved by suppressing the interchange coupling between adjacent ferromagnetic columnar phases.
  • the homogeneity of Nd-rich triple point and grain boundary phases is improved to reduce defects at the interface.
  • the nucleation site of reverse domains is reduced, thereby improving coercivity.
  • a metastable C type Nd 2 O 3 triple point phase and a grain boundary phase are formed. Because of this, lattice mismatch with the columnar phase can be greatly reduced and the coercivity can be improved.
  • FIG. 7 is a view for explaining the effect of the heat treatment after sintering the powder containing Cu.
  • the melting point of the Nd-rich phase is reduced to further improve the continuity and homogeneity of the grain boundary phase.
  • the non-magnetic properties of the Nd-rich triple point and the grain boundary phase are improved by the process decomposition reaction between Nd-Cu formed at about 520 ° C., so that the coercive force may be further improved.
  • Metastable C type Nd2O3 triple point and grain boundary phases are further promoted.
  • the existing ideal Cu content is known to be about 0.1 to 0.2 at.%. However, it is not clear why the ideal Cu content is 0.1 ⁇ 0.2at.%.
  • the sintering temperature is 1040 ° C ⁇ 1070 ° C (1070, 1060, 1050, 1040 ° C), the sintering time is 4 hours.
  • the first heat treatment (PSA, Post-sintering annealing) temperature is 700 °C ⁇ 850 °C (850, 820, 790, 760, 730, 700 °C), the heat treatment time is 2 hours.
  • the secondary heat treatment temperature is 530 ° C., and the heat treatment time is 2 hours.
  • the third heat treatment temperature is 500 °C, the heat treatment time is 2 hours.
  • FIG. 9 is a view showing a relationship between the content of Cu and the coercive force for the experimental example shown in FIG. 9 (a) relates to the first embodiment, FIG. 9 (b) relates to the second embodiment, and FIG. 9 (c) relates to the third embodiment.
  • Fig. 10 shows the microstructure on the Nd-rich triple point of a magnet containing 0.2 at.% Cu.
  • the bright part has a composition of Nd 40 Cu 6 Co 7 O 47 and a small amount of Cu is aggregated.
  • the bright part shows hexagonal Nd 2 O 3 crystal structure, the most stable phase.
  • Fig. 11 shows the microstructure on the Nd-rich triple point of a magnet containing 0.5 at.% Cu.
  • FIG. 11 also has a microstructure similar to that of FIG. 10.
  • Dark part has Nd 45 .2 Cu 36 .8 Co 2 .1 O 15 composition of 0.9 and are aggregated an excess of Cu. But the dark structure is hexagonal Nd 2 O 3 , not C-TYPE Nd 2 O 3 .
  • Bright parts have a composition of Nd 52 Cu 11 .6 .8 .6 Co 1 O 34, and a small amount of Cu is aggregated.
  • the bright part shows hexagonal Nd 2 O 3 crystal structure, the most stable phase.
  • FIG. 12 is a diagram for comparing the microstructure of the Nd-rich grain boundary phase with different Cu content.
  • the addition of Cu lowers the melting point of the Nd-rich phase. This may mean that not only the melting point but also the phase transformation temperature decreases.
  • Figure 14 (a) shows the case where the Cu content is 0.2at.%. Overall, the temperature is lower than that of Cu-free, and the stable hexagonal Nd2O3 phase is stabilized at 850 ° C.
  • Figure 14 (b) shows a case where the Cu content is 0.2at.%. It can be seen that the overall phase transformation temperature is so low that the fcc-NdO phase, not the stable hexagonal Nd 2 O 3 phase, is stabilized at 850 ° C.
  • the Nd 2 O 3 crystal of the metastable C-TYPE may be derived from the h-Nd 2 O 3 crystal structure.
  • the two decisions are closely related to each other. Therefore, when excessive Cu is agglomerated into the invasive sites on the hexagonal Nd 2 O 3 , it may be transformed into C-TYPE Nd 2 O 3 crystals.
  • FIG. 15 shows the coercive force and residual magnetization change with the primary heat treatment temperature of the sintered magnet containing 0.5 at.% Cu.
  • the coercivity is greatly improved when reduced from 850 °C to 790 °C (27.1-> 29.4 kOe).
  • existing ideal trace amounts of Cu may not be ideal compositions.
  • the coercive force can be further improved.
  • the coercive force of the sintered magnet can be improved without adding Dy. That is, Dy reduction type sintered magnets can be manufactured by inexpensive addition of Cu and optimization of heat treatment conditions according to its content.
  • FIG. 16 is a view illustrating a microstructure of a specimen when the heat treatment is performed at the heat treatment temperature shown in FIG. 8 and the heat treatment temperature shown in FIG. 15.
  • Figure 16 (a) shows a microstructure subjected to the heat treatment at a heat treatment temperature of 850 °C conventional method
  • Figure 16 (b) shows a micro structure subjected to the heat treatment at a heat treatment temperature of 790 °C changed according to the Cu content.
  • FIG. 17 is an image obtained by using high-resolution transmission electron microscopy (HRTEM) of FIG. 16 (b).
  • HRTEM high-resolution transmission electron microscopy
  • the first heat treatment temperature was lowered to refine the grains. This may contribute to an improvement in coercivity.
  • Nd-rich triple-phase and grain boundary phases as well as metastable C-TYPE Nd 2 O 3 with excessive Cu agglomeration, were formed again. This may contribute to an improvement in coercivity.
  • the heat treatment temperature is lowered as the Cu content is increased.
  • the permanent magnet produced according to another embodiment of the present invention changes the magnetic properties according to the sintering temperature at the time of filing.
  • FIG. 18 is a graph showing a change in magnetic specificity according to sintering temperature in relation to an embodiment of the present invention.
  • Figure 18 (a) shows the change of the magnetic properties according to the sintering temperature of the permanent magnet according to the second embodiment
  • Figure 18 (b) shows the magnetic properties of the permanent magnet according to the sintering temperature of the second embodiment Indicates a change.
  • the coercive force tends to increase as the sintering temperature decreases. Especially in the case of 0.2, 0.3 wt% Cu added, the coercive force increases rapidly when the sintering temperature is reduced from 1070 ° C to 1060 ° C at the first heat treatment temperature of 850 ° C. Similarly, the highest coercive force comes from specimens with a Cu content of 0.3 wt.% (Sintering temperature 1050 ° C / primary heat treatment 790 ° C).
  • the permanent magnet produced by another embodiment of the present invention changes the coercive force according to the change in the first heat treatment temperature at the time of filing.
  • 19 is a graph showing the coercive force change according to the first heat treatment temperature change in accordance with an embodiment of the present invention.
  • the optimal primary heat treatment temperature also tends to decrease as the Cu content increases.
  • the overall coercive force tends to increase.
  • the method of manufacturing a permanent magnet according to an embodiment of the present invention is to change the sintering temperature or the heat treatment temperature according to the Cu content, thereby reducing the amount of expensive Dy and manufacturing the permanent magnet with improved coercivity. Can be.
  • the manufacturing method of the permanent magnet described above is not limited to the configuration and method of the embodiments described above, the embodiments are a combination of all or part of each embodiment selectively so that various modifications can be made It may be configured.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Hard Magnetic Materials (AREA)
  • Manufacturing Cores, Coils, And Magnets (AREA)

Abstract

La présente invention concerne un procédé de fabrication d'un aimant permanent à base de Nd, Fe, B, présentant une force coercitive améliorée tout en réduisant la quantité de Dy utilisée. Un procédé de fabrication d'un aimant permanent selon un mode de réalisation de la présente invention peut comprendre les étapes consistant à : fabriquer une poudre comprenant Nd, Fe, B, et Cu; fabriquer un corps formé par formation d'un champ magnétique spécifique dans la poudre; fritter le corps formé à une température de frittage spécifique; et soumettre le corps formé fritté à un traitement thermique à une température de traitement thermique déterminée en fonction de la teneur en Cu.
PCT/KR2014/004647 2013-06-18 2014-05-23 Procédé de fabrication d'aimant permanent WO2014204106A1 (fr)

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US14/974,707 US20160104573A1 (en) 2013-06-18 2015-12-18 Method for manufacturing permanent magnet

Applications Claiming Priority (4)

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KR10-2013-0069517 2013-06-18
KR20130069517 2013-06-18
KR1020140030533A KR101527324B1 (ko) 2013-06-18 2014-03-14 영구 자석의 제조 방법
KR10-2014-0030533 2014-03-14

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109161941A (zh) * 2018-08-09 2019-01-08 浙江工业大学 一种烧结钕铁硼磁体铜复合石墨烯镀层打底以提高耐蚀性的方法及产品
CN113369818A (zh) * 2021-06-24 2021-09-10 马桂英 一种磁钢及磁钢加工方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0620813A (ja) * 1992-05-08 1994-01-28 Inter Metallics Kk 希土類異方性永久磁石粉末及びその製造法
KR20080110450A (ko) * 2006-04-14 2008-12-18 신에쓰 가가꾸 고교 가부시끼가이샤 희토류 영구자석 재료의 제조 방법
JP2011159983A (ja) * 2005-04-15 2011-08-18 Hitachi Metals Ltd 希土類焼結磁石とその製造方法
KR101165938B1 (ko) * 2010-03-31 2012-07-20 닛토덴코 가부시키가이샤 영구 자석 및 영구 자석의 제조 방법
KR20120086237A (ko) * 2011-01-25 2012-08-02 한양대학교 산학협력단 기계적 물성이 향상된 Ｒ－Ｆｅ－Ｂ계 소결자석 및 이의 제조방법

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0620813A (ja) * 1992-05-08 1994-01-28 Inter Metallics Kk 希土類異方性永久磁石粉末及びその製造法
JP2011159983A (ja) * 2005-04-15 2011-08-18 Hitachi Metals Ltd 希土類焼結磁石とその製造方法
KR20080110450A (ko) * 2006-04-14 2008-12-18 신에쓰 가가꾸 고교 가부시끼가이샤 희토류 영구자석 재료의 제조 방법
KR101165938B1 (ko) * 2010-03-31 2012-07-20 닛토덴코 가부시키가이샤 영구 자석 및 영구 자석의 제조 방법
KR20120086237A (ko) * 2011-01-25 2012-08-02 한양대학교 산학협력단 기계적 물성이 향상된 Ｒ－Ｆｅ－Ｂ계 소결자석 및 이의 제조방법

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109161941A (zh) * 2018-08-09 2019-01-08 浙江工业大学 一种烧结钕铁硼磁体铜复合石墨烯镀层打底以提高耐蚀性的方法及产品
CN113369818A (zh) * 2021-06-24 2021-09-10 马桂英 一种磁钢及磁钢加工方法
CN113369818B (zh) * 2021-06-24 2023-09-08 惠州市富正科技有限公司 一种磁钢及磁钢加工方法

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