WO2018209681A1 - Hot deformed magnet, and a method for preparing said hot deformed magnet - Google Patents

Hot deformed magnet, and a method for preparing said hot deformed magnet Download PDF

Info

Publication number
WO2018209681A1
WO2018209681A1 PCT/CN2017/085072 CN2017085072W WO2018209681A1 WO 2018209681 A1 WO2018209681 A1 WO 2018209681A1 CN 2017085072 W CN2017085072 W CN 2017085072W WO 2018209681 A1 WO2018209681 A1 WO 2018209681A1
Authority
WO
WIPO (PCT)
Prior art keywords
hot deformed
hot
deformed magnet
magnet
green body
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
Application number
PCT/CN2017/085072
Other languages
French (fr)
Inventor
Xin TANG
Hossein SEPEHRI-AMIN
Tadaktsu OHKUBO
Kazuhiro Hono
Jiaqing Yu
Bicheng Chen
Witold Pieper
Juergen Oberle
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
National Institute for Materials Science
Original Assignee
Robert Bosch GmbH
National Institute for Materials Science
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.)
Filing date
Publication date
Application filed by Robert Bosch GmbH, National Institute for Materials Science filed Critical Robert Bosch GmbH
Priority to JP2019563829A priority Critical patent/JP6865857B2/en
Priority to PCT/CN2017/085072 priority patent/WO2018209681A1/en
Priority to EP17910333.8A priority patent/EP3625807B1/en
Priority to CN201780090979.8A priority patent/CN110753978B/en
Publication of WO2018209681A1 publication Critical patent/WO2018209681A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Images

Classifications

    • 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
    • H01F1/0576—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 pressed, e.g. hot working

Definitions

  • the present invention relates to a hot deformed magnet, as well as a method for preparing said hot deformed magnet.
  • rare earth/iron/boron-based permanent magnet exhibits high remanence and coercivty, provides a high magnetic flux within a specific temperature range (for example -40 ⁇ 180 °C for EV/HEV traction motor) , and makes the electric motor have superior performances, for example high power density, high torque density and high efficiency.
  • the coercivity is the magnitude of magnetic field at which the magnetization of a permanent magnet is reduced to zero. It stands for the ability of the permanent magnet to generate a magnetic flux against the demagnetization field and also the ability of the permanent magnet to generate a magnetic flux agaist the high working temperature.
  • the remanence represents the magnitude of the maximum magnetic flux which can be generated by the permanent magnet. It represents the ability of the permanent magnet to provide a magnetic moment. Normally a high remanence is favorable to render a permanent magnet thinner and lighter in case of a fixed magnetic moment, and consequently reduce the size and volume of an electric motor, which is desirable for many applications.
  • Coarsen grain regions are mainly generated at the original place of the magnetic powder particulate surfaces during the hot deformation.
  • the RE 2 F 14 B grains are almost equiaxed instead of platelet, and often have a dimension of greater than 400 nm. These equiaxed large RE 2 F 14 B grains exhibit a low magnetic orientation, a low ability against the demagnetization field, and consequently deteriorated magnetic properties. Due to the presence of coarsen grain regions, a remanence as high as 1.45 T or above normally can not be achieved for the conventional hot deformed magnets.
  • the object of the present invention is to provide a hot deformed magnet which has enhanced magnetic properties, especially enhanced remanence and coercivity, and almost has no coarse equiaxed grains with a diameter greater than 400 nm and consequently no coarse equiaxed grain regions in the microstructure.
  • Said object can be achieved by a hot deformed magnet having an alloy composition of the formula (1)
  • RE is one or more rare earth elements, such as La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, and Lu, preferably Pr, Nd, Tb, and Dy;
  • T is one or more elements selected from the group consisting of Co, Al, Ga, Zr, Ti and Mo;
  • M is Nb and/or Ta
  • Cu is copper
  • B is boron
  • the balance is Fe and inevitable impurities
  • x is 13.0 ⁇ 15.0 at. %
  • y1 is 1.2 ⁇ 10.0 at. %
  • y2 is 0.1 ⁇ 0.8 at. %
  • z1 is 0 ⁇ 0.5 at. %
  • z2 is 4.5 ⁇ 6.5 at. %.
  • Said object can be achieved by a method for preparing the hot deformed magnet according to the present invention, said method including the following steps:
  • RE is one or more rare earth elements, such as La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, and Lu, preferably Pr, Nd, Tb, and Dy;
  • T is one or more elements selected from the group consisting of Co, Al, Ga, Zr, Ti and Mo;
  • M is Nb and/or Ta
  • Cu is copper
  • B is boron
  • the balance is Fe and inevitable impurities
  • x is 13.0 ⁇ 15.0 at. %
  • y1 is 1.2 ⁇ 10.0 at. %
  • y2 is 0.1 ⁇ 0.8 at. %
  • z1 is 0 ⁇ 0.5 at. %
  • z2 is 4.5 ⁇ 6.5 at. %
  • step 3 hot deforming the green body prepared from step 2) to obtain the hot deformed magnet.
  • Figure 1 shows the magnetization curves of the hot deformed magnets without Nb (a) (Example 1) and with about 0.2%of Nb (b) (Example 2) ;
  • Figure 2 shows the back-scattered SEM images of the hot deformed magnets without Nb (a) and (c) (Example 1) and with about 0.2%of Nb (b) and (d) (Example 2) ;
  • Figure 3 shows the BSE-SEM images of the hot deformed magnets without Nb (a) (Example 1) and with about 0.2%of Nb (b) (Example 2) ;
  • Figure 4 shows the STEM-EDS mapping of Nd and Nb of the hot deformed magnets with about 0.2%of Nb (a) (Example 2) and with about 0.6%of Nb (b) (Example 4) .
  • the present invention relates to a hot deformed magnet having an alloy composition of the formula (1)
  • RE is one or more rare earth elements, such as La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, and Lu, preferably Pr, Nd, Tb, and Dy;
  • T is one or more elements selected from the group consisting of Co, Al, Ga, Zr, Ti and Mo;
  • M is Nb and/or Ta
  • Cu is copper
  • B is boron
  • the balance is Fe and inevitable impurities
  • x is 13.0 ⁇ 15.0 at. %
  • y1 is 1.2 ⁇ 10.0 at. %
  • y2 is 0.1 ⁇ 0.8 at. %
  • z1 is 0 ⁇ 0.5 at. %
  • z2 is 4.5 ⁇ 6.5 at. %.
  • the hot deformed magnet can contain a predominant magnetic phase and one or more grain boundary phases.
  • the predominant magnetic phase is the RE 2 Fe 14 B phase having a tetragonal crystal structure.
  • the formula RE 2 Fe 14 B as used herein includes all the compositions having the RE 2 Fe 14 B tetragonal crystal structure, which may or may not include any other elements as stated above, as long as these other elements do not destroy the RE 2 Fe 14 B tetragonal crystal structure.
  • the specific compositions and crystal structures of said one or more grain boundary phases are quite complicated. At least one of the grain boundary phases are believed to have a lower melting temperature and a greater proportion of rare earth element (s) than those of the predominant magnetic phase, and therefore, can also be called as RE-rich phase. Another grain boundary phase is believed to be present in form of nano-sized Nb-rich and/or Ta-rich precipatets.
  • the hot deformed magnet can exhibit anisotropy with a RE 2 Fe 14 B grain morphology in form of platelet.
  • the hot deformed magnet can exhibit anisotropy with the crystallographic c-axes of the RE 2 Fe 14 B grains aligned or orientated substantially parallel to one another.
  • the crystallographic c-axes of the RE 2 Fe 14 B grains in form of platelet are perpendicular to the major surfaces of the platelets and parallel to their smallest dimension.
  • the preferred magnetic alignment direction of the RE 2 Fe 14 B grains is along their crystallographic c-axes.
  • the thickness of the platelet can be up to 200 nm, preferably 25 ⁇ 120 nm, more preferably 25 ⁇ 100 nm. In the context of the present invention, the thickness of the platelet shall be understood as its smallest dimension.
  • the length of the platelet can be up to 1 ⁇ m, preferably 100 ⁇ 600 nm, more preferably 100 ⁇ 300 nm. In the context of the present invention, the length of the platelet shall be understood as its largest dimension.
  • the hot deformed magnet almost has no coarse equiaxed grains with a diameter greater than 400 nm and consequently no coarse equiaxed grain regions in the microstructure.
  • the present invention relates to a method for preparing the hot deformed magnet according to the present invention, including the following steps:
  • RE is one or more rare earth elements, such as La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, and Lu, preferably Pr, Nd, Tb, and Dy;
  • T is one or more elements selected from the group consisting of Co, Al, Ga, Zr, Ti and Mo;
  • M is Nb and/or Ta
  • Cu is copper
  • B is boron
  • the balance is Fe and inevitable impurities
  • x is 13.0 ⁇ 15.0 at. %
  • y1 is 1.2 ⁇ 10.0 at. %
  • y2 is 0.1 ⁇ 0.8 at. %
  • z1 is 0 ⁇ 0.5 at. %
  • z2 is 4.5 ⁇ 6.5 at. %
  • step 3 hot deforming the green body prepared from step 2) to obtain the hot deformed magnet.
  • magnetic powders can be prepared by melt quenching from an ingot having the alloy composition of the formula (1) .
  • the ingot can be melted at a temperature of above 1000 °C, preferably 1000 ⁇ 1100 °C, preferably under a protect atmosphere, such as Argon, and then cast or injected onto a rotating wheel, such as a copper wheel, with a circumferential velocity of 10 ⁇ 40 m/s, so as to obtain melt-spun ribbons or magnetic powders.
  • the cooling rate can be set according to the circumferential velocity of the rotating wheel and the amount of the molten metal cast or injected.
  • melt-spun ribbons can be directly obtained by melt quenching from the ingot, and preferably have a thickness of less than 50 ⁇ m. Then the melt-spun ribbons can be optionally crushed into magnetic powders preferably having a length of less than 200 ⁇ m.
  • the magnetic powders or the melt-spun ribbons can be crystalline or even amorphous, or have crystallitic grains with a grain size of less than 50 nm, in each case according to the cooling rate.
  • step 2) the magnetic powders prepared from step 1) can be pressed to obtain a green body.
  • the magnetic powders prepared from step 1) can be cold pressed at room temperature, wherein the pressure and the duration of the cold pressing are not particularly limited and can be selected in such a way to reach up to 70%or even more of the saturated density, for example 50 ⁇ 400 MPa and 1 ⁇ 5 seconds; and then hot pressed to obtain the green body, wherein the temperature of the hot pressing is not particularly limited, for example 550 ⁇ 850 °C, preferably 600 ⁇ 700 °C, and can be selected in such a way not to liquefy the predominant magnetic phase, but liquefy the grain boundary phase sufficiently, otherwise the densification might be insufficient and even cracks might be initiated and propagated in the green body; the pressure of the hot pressing is not particularly limited, for example 20 ⁇ 200 MPa, preferably 20 ⁇ 100 MPa, and can be selected in such a way to reach the full densification; the duration of the hot pressing is not particularly limited, for example 10 ⁇ 240 seconds, and can be selected
  • step 3) the green body prepared from step 2) can be hot deformed to obtain the hot deformed magnet.
  • the green body prepared from step 2) can be hot deformed, for example by extrusion, or die up-setting, so as to reshape the green body into the predetermined shape and geometry, such as cylinder, rectangular block or segment, and simultaneously align the crystallographic c-axes of the RE 2 Fe 14 B grains to the predetermined direction, and finally obtain the hot deformed magnet, wherein the temperature of the hot deformation is not particularly limited, for example 750 ⁇ 850 °C, preferably 780 ⁇ 820 °C, and can be selected in such a way to subject the green body to a plastic deformation, but not initiate and propagate cracks in the green body; the pressure of the hot deformation is not particularly limited, for example 20 ⁇ 250 MPa, preferably 20 ⁇ 200 MPa; and the atmosphere of the hot deformation is not particularly limited, for example an inert gas protected atmosphere, a reduction atmosphere, vacuum or a low oxidation atmosphere.
  • the temperature of the hot deformation is not particularly limited, for example 750 ⁇ 850 °
  • the anisotropy of the RE 2 Fe 14 B grains can be achieved based on such a mechanism that the RE 2 Fe 14 B grains can rotate during the hot deformation under pressure with the help of the grain boundary phase liquefied at the hot deformation temperature, so that the crystallographic c-axes of the RE 2 Fe 14 B grains can be aligned or orientated substantially parallel to one another.
  • the crystallographic c-axes of the RE 2 Fe 14 B grains in form of platelet are perpendicular to the major surfaces of the platelets and parallel to their smallest dimension.
  • the preferred magnetic alignment direction of the RE 2 Fe 14 B grains is along their crystallographic c-axes.
  • the hot deformed magnet can be further processed by thermal annealing, grain boundary diffusion or other post treatment under cold or warm conditions.
  • Raw materials according to the alloy compositions as listed in Table 1 were melted under Argon at a temperature of above 1000 °C until homogeneous, and cast into ingots.
  • the ingots were melted again under Argon at a temperature of above 1000 °C, and then injected onto a copper wheel with a circumferential velocity of 20 m/sto obtain melt-spun ribbons. Then the melt-spun ribbons were crushed into magnetic powders having a length of less than 200 ⁇ m.
  • the magnetic powders prepared from step 1) were cold pressed at room temperature for about 5 seconds to reach at least 70%of the saturated density, and then hot pressed under vacuum at about 700 °C and about 100 MPa for about 120 seconds to obtain green bodies.
  • the green bodies prepared from step 2) were hot deformed by extrusion under vacuum at about 800 °C and about 180 MPa to obtain hot deformed magnets.
  • Figure 1 shows the magnetization curves of the hot deformed magnets without Nb (a) (Example 1) and with about 0.2%of Nb (b) (Example 2) .
  • the magnetic properties of the hot deformed magnets prepared according to Examples 1 ⁇ 5 are listed in Table 2.
  • the hot deformed magnets prepared according to Examples 1 ⁇ 5 exhibit very high remanences, for example 1.54 T as the highest and a corresponding anisotropy of 0.96, wherein the anisotropy is represented as the ratio of the remanence to the saturation magnetic flux density of 1.6 T.
  • Figure 2 shows the back-scattered SEM images of the hot deformed magnets without Nb (a) and (c) (Example 1) and with about 0.2%of Nb (b) and (d) (Example 2) .
  • the platelet-shaped morphology of the RE 2 Fe 14 B grains has been optimized by adding Nb.
  • both the grain size and the aspect ratio of the RE 2 Fe 14 B grains have been reduced, which is beneficial to enhance the coercivity and the thermal stability of the coericivty of the hot deformed magnets.
  • the aspect ratio of the platelet shall be understood as the ratio of the length to the thickness of the platelet.
  • Figure 3 shows the BSE-SEM images of the hot deformed magnets without Nb (a) (Example 1) and with about 0.2%of Nb (b) (Example 2) . It is apparent from Figure 3 that both the grain size and the aspect ratio of the RE 2 Fe 14 B grains have been reduced.
  • Figure 4 shows the STEM-EDS mapping of Nd and Nb of the hot deformed magnets with about 0.2%of Nb (a) (Example 2) and with about 0.6%of Nb (b) (Example 4) .
  • Nb mainly forms nano-sized Nb-rich precipitates at the grain boundary and slightly segregates inside the RE 2 Fe 14 B grains.
  • Hot deformed magnet includes, but are not limited to, electric motor for automotives, power tools, home appliances, drive &control, and others.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Hard Magnetic Materials (AREA)
  • Continuous Casting (AREA)
  • Manufacture Of Metal Powder And Suspensions Thereof (AREA)
  • Powder Metallurgy (AREA)
  • Manufacturing Cores, Coils, And Magnets (AREA)

Abstract

A hot deformed magnet, as well as a method for preparing said hot deformed magnet. The hot deformed magnet having an alloy composition of the formula (1), RE xFe (100-x-y1-y2-z1-z2) T y1M y2Cu z1B z2 (1), wherein RE is one or more rare earth elements, such as La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, and Lu；T is one or more elements selected from the group consisting of Co, Al, Ga, Zr, Ti and Mo；M is Nb and/or Ta；Cu is copper；B is boron；the balance is Fe and inevitable impurities.

Description

HOT DEFORMED MAGNET, AND A METHOD FOR PREPARING SAID HOT DEFORMED MAGNET Technical Field
The present invention relates to a hot deformed magnet, as well as a method for preparing said hot deformed magnet.
Background Art
Generally, rare earth/iron/boron-based permanent magnet exhibits high remanence and coercivty, provides a high magnetic flux within a specific temperature range (for example -40 ～ 180 ℃ for EV/HEV traction motor) , and makes the electric motor have superior performances, for example high power density, high torque density and high efficiency.
The coercivity is the magnitude of magnetic field at which the magnetization of a permanent magnet is reduced to zero. It stands for the ability of the permanent magnet to generate a magnetic flux against the demagnetization field and also the ability of the permanent magnet to generate a magnetic flux agaist the high working temperature.
The remanence represents the magnitude of the maximum magnetic flux which can be generated by the permanent magnet. It represents the ability of the permanent magnet to provide a magnetic moment. Normally a high remanence is favorable to render a permanent magnet thinner and lighter in case of a fixed magnetic moment, and consequently reduce the size and volume of an electric motor, which is desirable for many applications.
Coarsen grain regions are mainly generated at the original place of the magnetic powder particulate surfaces during the hot deformation. In the coarsen grain regions, the RE2F14B grains are almost equiaxed instead of platelet, and often have a dimension of greater than 400 nm. These equiaxed large RE2F14B grains exhibit a low magnetic orientation, a low ability against the demagnetization field, and consequently deteriorated magnetic properties. Due to the presence of coarsen grain regions, a remanence as high as 1.45 T or above normally can not be achieved for the conventional hot deformed magnets.
Although great efforts on the design of the alloy composition and the preparation method for the rare earth/iron/boron-based magnetic powders and hot deformed magnets have been made in the prior art, the issue of coarse equiaxed grains or coarsen grain regions is still not overcome for the known magnetic powders and hot deformed magnets.
Summary of Invention
The object of the present invention is to provide a hot deformed magnet which has enhanced magnetic properties, especially enhanced remanence and coercivity, and almost has no coarse equiaxed grains with a diameter greater than 400 nm and consequently no coarse equiaxed grain regions in the microstructure.
Said object, according to one aspect, can be achieved by a hot deformed magnet having an alloy composition of the formula (1)
RExFe (100-x-y1-y2-z1-z2) Ty1My2Cuz1Bz2      (1) ,
wherein
RE is one or more rare earth elements, such as La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, and Lu, preferably Pr, Nd, Tb, and Dy；
T is one or more elements selected from the group consisting of Co, Al, Ga, Zr, Ti and Mo；
M is Nb and/or Ta；
Cu is copper；
B is boron；
the balance is Fe and inevitable impurities；
x is 13.0 ～ 15.0 at. ％；
y1 is 1.2 ～ 10.0 at. ％；
y2 is 0.1 ～ 0.8 at. ％；
z1 is 0 ～ 0.5 at. ％； and
z2 is 4.5 ～ 6.5 at. ％.
Said object, according to another aspect, can be achieved by a method for preparing the hot deformed magnet according to the present invention, said method including the following steps:
1) preparing magnetic powders by melt quenching from an ingot having an alloy composition of the formula (1)
RExFe (100-x-y1-y2-z1-z2) Ty1My2Cuz1Bz2       (1) ,
wherein
RE is one or more rare earth elements, such as La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, and Lu, preferably Pr, Nd, Tb, and Dy；
T is one or more elements selected from the group consisting of Co, Al, Ga, Zr, Ti and Mo；
M is Nb and/or Ta；
Cu is copper；
B is boron；
the balance is Fe and inevitable impurities；
x is 13.0 ～ 15.0 at. ％；
y1 is 1.2 ～ 10.0 at. ％；
y2 is 0.1 ～ 0.8 at. ％；
z1 is 0 ～ 0.5 at. ％； and
z2 is 4.5 ～ 6.5 at. ％；
2) pressing the magnetic powders prepared from step 1) to obtain a green body； and
3) hot deforming the green body prepared from step 2) to obtain the hot deformed magnet.
Brief Description of Drawings
Each aspect of the present invention will be illustrated in more detail in conjunction with the accompanying drawings, wherein :
Figure 1 shows the magnetization curves of the hot deformed magnets without Nb (a) (Example 1) and with about 0.2％of Nb (b) (Example 2) ；
Figure 2 shows the back-scattered SEM images of the hot deformed magnets without Nb (a) and (c) (Example 1) and with about 0.2％of Nb (b) and (d) (Example 2) ；
Figure 3 shows the BSE-SEM images of the hot deformed magnets without Nb (a) (Example 1) and with about 0.2％of Nb (b) (Example 2) ；
Figure 4 shows the STEM-EDS mapping of Nd and Nb of the hot deformed magnets with about 0.2％of Nb (a) (Example 2) and with about 0.6％of Nb (b) (Example 4) .
Detailed Description of Preferred Embodiments
All publications, patent applications, patents and other references mentioned herein, if not otherwise indicated, are explicitly incorporated by reference herein in their entirety for all purposes as if fully set forth.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, including definitions, will control.
When an amount, concentration, or other value or parameter is given as either a range, preferred range or a list of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. Where a range of numerical values is recited herein, unless otherwise stated, the range is intended to include the endpoints thereof, and all integers and fractions within the range.
The present invention, according to one aspect, relates to a hot deformed magnet having an alloy composition of the formula (1)
RExFe (100-x-y1-y2-z1-z2) Ty1My2Cuz1Bz2       (1) ,
wherein
RE is one or more rare earth elements, such as La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, and Lu, preferably Pr, Nd, Tb, and Dy；
T is one or more elements selected from the group consisting of Co, Al, Ga, Zr, Ti and Mo；
M is Nb and/or Ta；
Cu is copper；
B is boron；
the balance is Fe and inevitable impurities；
x is 13.0 ～ 15.0 at. ％；
y1 is 1.2 ～ 10.0 at. ％；
y2 is 0.1 ～ 0.8 at. ％；
z1 is 0 ～ 0.5 at. ％； and
z2 is 4.5 ～ 6.5 at. ％.
In accordance with an embodiment of the hot deformed magnet according to the present invention, the hot deformed magnet can contain a predominant magnetic phase and one or more grain boundary phases.
In particular, the predominant magnetic phase is the RE2Fe14B phase having a tetragonal crystal structure. In the context of the present invention, the formula RE2Fe14B as used herein includes all the compositions having the RE2Fe14B tetragonal crystal structure, which may or may not include any other elements as stated above, as long as these other elements do not destroy the RE2Fe14B tetragonal crystal structure.
On the other hand, the specific compositions and crystal structures of said one or more grain boundary phases are quite complicated. At least one of the grain boundary phases are believed to have a lower melting temperature and a greater proportion of rare earth element (s) than those of the predominant magnetic phase, and therefore, can also be called as RE-rich phase. Another grain boundary phase is believed to be present in form of nano-sized Nb-rich and/or Ta-rich precipatets.
In accordance with another embodiment of the hot deformed magnet according to the present invention, the hot deformed magnet can exhibit anisotropy with a RE2Fe14B grain morphology in form of platelet. In particular, the hot deformed magnet can exhibit anisotropy with the crystallographic c-axes of the RE2Fe14B grains aligned or orientated substantially parallel to one another. The crystallographic c-axes of the RE2Fe14B grains in form of platelet are perpendicular to the major surfaces of the platelets and parallel to their smallest dimension. The preferred magnetic alignment direction of the RE2Fe14B grains is along their crystallographic c-axes.
In accordance with another embodiment of the hot deformed magnet according to the present invention, the thickness of the platelet can be up to 200 nm, preferably 25 ～ 120 nm, more preferably 25 ～ 100 nm. In the context of the present invention, the thickness of the platelet shall be understood as its smallest dimension.
In accordance with another embodiment of the hot deformed magnet according to the present invention, the length of the platelet can be up to 1 μm, preferably 100 ～ 600 nm, more preferably 100 ～ 300 nm. In the context of the present invention, the length of the platelet shall be understood as its largest dimension.
In accordance with another embodiment of the hot deformed magnet according to the present invention, the hot deformed magnet almost has no coarse equiaxed grains with a diameter greater than 400 nm and consequently no coarse equiaxed grain regions in the microstructure.
The present invention, according to another aspect, relates to a method for preparing the hot deformed magnet according to the present invention, including the following steps:
1) preparing magnetic powders by melt quenching from an ingot having an alloy composition of the formula (1)
RExFe (100-x-y1-y2-z1-z2) Ty1My2Cuz1Bz2        (1) ,
wherein
RE is one or more rare earth elements, such as La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, and Lu, preferably Pr, Nd, Tb, and Dy；
T is one or more elements selected from the group consisting of Co, Al, Ga, Zr, Ti and Mo；
M is Nb and/or Ta；
Cu is copper；
B is boron；
the balance is Fe and inevitable impurities；
x is 13.0 ～ 15.0 at. ％；
y1 is 1.2 ～ 10.0 at. ％；
y2 is 0.1 ～ 0.8 at. ％；
z1 is 0 ～ 0.5 at. ％； and
z2 is 4.5 ～ 6.5 at. ％；
2) pressing the magnetic powders prepared from step 1) to obtain a green body； and
3) hot deforming the green body prepared from step 2) to obtain the hot deformed magnet.
1) Preparation of magnetic powders
In step 1) , magnetic powders can be prepared by melt quenching from an ingot having the alloy composition of the formula (1) .
In accordance with an embodiment of the method according to the present invention, the ingot can be melted at a temperature of above 1000 ℃, preferably 1000 ～ 1100 ℃, preferably under a protect atmosphere, such as Argon, and then cast or injected onto a rotating wheel, such as a copper wheel, with a circumferential velocity of 10 ～ 40 m/s, so as to obtain melt-spun ribbons or magnetic powders. The cooling rate can be set according to the circumferential velocity of the rotating wheel and the amount of the molten metal cast or injected.
In accordance with another embodiment of the method according to the present invention, melt-spun ribbons can be directly obtained by melt quenching from the ingot, and preferably have a thickness of less than 50 μm. Then the melt-spun ribbons can be optionally crushed into magnetic powders preferably having a length of less than 200 μm.
In accordance with another embodiment of the method according to the present invention, the magnetic powders or the melt-spun ribbons can be crystalline or even amorphous, or have crystallitic grains with a grain size of less than 50 nm, in each case according to the cooling rate.
2) Pressing
In step 2) , the magnetic powders prepared from step 1) can be pressed to obtain a green body.
In accordance with another embodiment of the method according to the present invention, the magnetic powders prepared from step 1) can be cold pressed at room temperature, wherein the pressure and the duration of the cold pressing are not particularly limited and can be selected in such a way to reach up to 70％or even more of the saturated density, for example 50 ～ 400 MPa and 1 ～ 5 seconds； and then hot pressed to obtain the green body, wherein the temperature of the hot pressing is not particularly limited, for example 550 ～ 850 ℃, preferably 600 ～ 700 ℃, and can be selected in such a way not to liquefy the predominant magnetic phase, but liquefy the grain boundary phase sufficiently, otherwise the densification might be insufficient and even cracks might be initiated and propagated in the green body； the pressure of the hot pressing is not particularly limited, for example 20 ～ 200 MPa, preferably 20 ～ 100 MPa, and can be selected in such a way to reach the full densification； the duration of the hot pressing is not particularly limited, for example 10 ～ 240 seconds, and can be selected in such a way to reach the full densification, but shall not be too long to cause abnormal growth of the RE4Fe14B grains and consequently deteriorate the microstructure of the green body； and the atmosphere of the hot pressing is not particularly limited, for example an inert gas protected atmosphere, an oxidation atmosphere, a reduction atmosphere, and vacuum, preferably vacuum.
3) Hot deformation
In step 3) , the green body prepared from step 2) can be hot deformed to obtain the hot deformed magnet.
In accordance with another embodiment of the method according to the present invention, the green body prepared from step 2) can be hot deformed, for example by extrusion, or die up-setting, so as to reshape the green body into the predetermined shape and geometry, such as cylinder, rectangular block or segment, and simultaneously align the crystallographic c-axes of the RE2Fe14B grains to the predetermined direction, and finally obtain the hot deformed magnet, wherein the temperature of the hot deformation is not particularly limited, for example 750 ～ 850 ℃, preferably 780 ～ 820 ℃, and can be selected in such a way to subject the green body to a plastic deformation, but not initiate and propagate cracks in the green body； the pressure of the hot deformation is not particularly limited, for example 20 ～ 250 MPa, preferably 20 ～ 200 MPa； and the atmosphere of the hot deformation is not particularly limited, for example an inert gas protected atmosphere, a reduction atmosphere, vacuum or a low oxidation atmosphere.
The anisotropy of the RE2Fe14B grains can be achieved based on such a mechanism that the RE2Fe14B grains can rotate during the hot deformation under pressure with the help of the grain boundary phase liquefied at the hot deformation temperature, so that the crystallographic c-axes of the RE2Fe14B grains can be aligned or orientated substantially parallel to one another. The crystallographic c-axes of the RE2Fe14B grains in form of platelet are perpendicular to the major surfaces of the platelets and parallel to their smallest  dimension. The preferred magnetic alignment direction of the RE2Fe14B grains is along their crystallographic c-axes.
In accordance with another embodiment of the method according to the present invention, the hot deformed magnet can be further processed by thermal annealing, grain boundary diffusion or other post treatment under cold or warm conditions.
Examples
1) Preparation of magnetic powders
Raw materials according to the alloy compositions as listed in Table 1 were melted under Argon at a temperature of above 1000 ℃ until homogeneous, and cast into ingots. The ingots were melted again under Argon at a temperature of above 1000 ℃, and then injected onto a copper wheel with a circumferential velocity of 20 m/sto obtain melt-spun ribbons. Then the melt-spun ribbons were crushed into magnetic powders having a length of less than 200 μm.
Table 1 Alloy compositions according to Examples 1 ～ 19 (all in at. ％)
Example Nd Fe Co B Al Ga Nb Cu
1 12.83 75.97 4.5 5.31 0.43 0.53 0 0
2 12.59 75.67 4.5 5.44 0.67 0.52 0.21 0
3 12.9 75.21 4.49 5.52 0.55 0.51 0.4 0
4 13.09 74.87 4.49 5.56 0.48 0.52 0.64 0
5 13.41 75.42 4.33 5.3 0.31 0.51 0.22 0.19
6 14.42 75.33 4.5 5.22 0 0.53 0 0
7 14.42 75.13 4.5 5.22 0 0.53 0.2 0
8 14.42 74.93 4.5 5.22 0 0.53 0.4 0
9 14.42 74.73 4.5 5.22 0 0.53 0.6 0
10 14.42 74.93 4.5 5.22 0 0.53 0.2 0.2
11 13.64 75.29 4.51 5.58 0.4 0.54 0 0
12 13.52 75.13 4.48 5.51 0.5 0.53 0.2 0
13 13.5 74.99 4.51 5.54 0.5 0.52 0.41 0
14 13.56 74.74 4.5 5.58 0.5 0.53 0.61 0
15 14.15 75.11 4.5 5.09 0.3 0.52 0.17 0.19
16 13 75.54 4.48 5.4 0.63 0.52 0.21 0
17 13.03 75.17 4.49 5.38 0.57 0.51 0.4 0
18 12.88 75.14 4.49 5.47 0.51 0.51 0.66 0
19 13 75.85 4.07 5.34 0.34 0.52 0.25 0.19
2) Pressing
The magnetic powders prepared from step 1) were cold pressed at room temperature for about 5 seconds to reach at least 70％of the saturated density, and then hot pressed under vacuum at about 700 ℃ and about 100 MPa for about 120 seconds to obtain green bodies.
3) Hot deformation
The green bodies prepared from step 2) were hot deformed by extrusion under vacuum at about 800 ℃ and about 180 MPa to obtain hot deformed magnets.
Evaluation of magnetic properties
Figure 1 shows the magnetization curves of the hot deformed magnets without Nb (a) (Example 1) and with about 0.2％of Nb (b) (Example 2) . The magnetic properties of the hot deformed magnets prepared according to Examples 1 ～ 5 are listed in Table 2.
Table 2 Magnetic properties of the magnets according to Examples 1 ～ 5
Figure PCTCN2017085072-appb-000001
The hot deformed magnets prepared according to Examples 1 ～ 5 exhibit very high remanences, for example 1.54 T as the highest and a corresponding anisotropy of 0.96, wherein the anisotropy is represented as the ratio of the remanence to the saturation magnetic flux density of 1.6 T.
It is also apparent from Table 2 that the remanence has been increased from 1.48 T (no Nb) to 1.54 T (about 0.2％of Nb) , and the coercivity also has been enhanced from 0.77 T (no Nb) to 1.08 T (about 0.2％of Nb) .
Evaluation of microstructure
Figure 2 shows the back-scattered SEM images of the hot deformed magnets without Nb (a) and (c) (Example 1) and with about 0.2％of Nb (b) and (d) (Example 2) .
It is apparent from Figure 2 that the formation of coarsen grains or coarsen grain regions in the microstructure of the hot deformed magnets has been suppressed by adding small amount of Nb. A microstructure almost having no coarse equiaxed grains with a diameter  greater than 400 nm and consequently no coarse equiaxed grain regions is favorable for the magnetic properties of the hot deformed magnets.
It is also apparent from Figure 2 that the platelet-shaped morphology of the RE2Fe14B grains has been optimized by adding Nb. In particular, both the grain size and the aspect ratio of the RE2Fe14B grains have been reduced, which is beneficial to enhance the coercivity and the thermal stability of the coericivty of the hot deformed magnets. In the context of the present invention, the aspect ratio of the platelet shall be understood as the ratio of the length to the thickness of the platelet.
Figure 3 shows the BSE-SEM images of the hot deformed magnets without Nb (a) (Example 1) and with about 0.2％of Nb (b) (Example 2) . It is apparent from Figure 3 that both the grain size and the aspect ratio of the RE2Fe14B grains have been reduced.
Figure 4 shows the STEM-EDS mapping of Nd and Nb of the hot deformed magnets with about 0.2％of Nb (a) (Example 2) and with about 0.6％of Nb (b) (Example 4) .
It is apparent from the Nb mapping in the microstructure of the hot deformed magnets that Nb mainly forms nano-sized Nb-rich precipitates at the grain boundary and slightly segregates inside the RE2Fe14B grains.
Potential applications of the hot deformed magnet according to the present invention include, but are not limited to, electric motor for automotives, power tools, home appliances, drive &control, and others.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. The attached claims and their equivalents are intended to cover all the modifications, substitutions and changes as would fall within the scope and spirit of the invention.

Claims (9)

  1. A hot deformed magnet having an alloy composition of the formula (1) 
    RExFe (100-x-y1-y2-z1-z2) Ty1My2Cuz1Bz2   (1) ,
    wherein
    RE is one or more rare earth elements, such as La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, and Lu, preferably Pr, Nd, Tb, and Dy；
    T is one or more elements selected from the group consisting of Co, Al, Ga, Zr, Ti and Mo；
    M is Nb and/or Ta；
    Cu is copper；
    B is boron；
    the balance is Fe and inevitable impurities；
    x is 13.0 ～ 15.0 at. ％；
    y1 is 1.2 ～ 10.0 at. ％；
    y2 is 0.1 ～ 0.8 at. ％；
    z1 is 0 ～ 0.5 at. ％； and
    z2 is 4.5 ～ 6.5 at. ％.
  2. The hot deformed magnet of claim 1, characterized in that the hot deformed magnet exhibits anisotropy with a RE2Fe14B grain morphology in form of platelet.
  3. The hot deformed magnet of claim 2, characterized in that the thickness of the platelet is up to 200 nm, preferably 25 ～ 120 nm, more preferably 25 ～ 100 nm.
  4. The hot deformed magnet of claim 2 or 3, characterized in that the length of the platelet is up to 1 μm, preferably 100 ～ 600 nm, more preferably 100 ～ 300 nm.
  5. The hot deformed magnet of any one of claims 1 to 4, characterized in that the hot deformed magnet almost has no coarse equiaxed grains with a diameter greater than 400 nm and consequently no coarse equiaxed grain regions in the microstructure.
  6. A method for preparing the hot deformed magnet of any one of claims 1 to 5, said method including the following steps:
    1) preparing magnetic powders by melt quenching from an ingot having an alloy composition of the formula (1)
    RExFe (100-x-y1-y2-z1-z2) Ty1My2Cuz1Bz2   (1) ,
    wherein
    RE is one or more rare earth elements, such as La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, and Lu, preferably Pr, Nd, Tb, and Dy；
    T is one or more elements selected from the group consisting of Co, Al, Ga, Zr, Ti and Mo；
    M is Nb and/or Ta；
    Cu is copper；
    B is boron；
    the balance is Fe and inevitable impurities；
    x is 13.0 ～ 15.0 at. ％；
    y1 is 1.2 ～ 10.0 at. ％；
    y2 is 0.1 ～ 0.8 at. ％；
    z1 is 0 ～ 0.5 at. ％； and
    z2 is 4.5 ～ 6.5 at. ％；
    2) pressing the magnetic powders prepared from step 1) to obtain a green body； and
    3) hot deforming the green body prepared from step 2) to obtain the hot deformed magnet.
  7. The method of claim 6, characterized in that in step 1) , the ingot is melted at a temperature of above 1000 ℃, preferably 1000 ～ 1100 ℃, and then cast or injected onto a rotating wheel with a circumferential velocity of 10 ～ 40 m/s.
  8. The method of claim 6 or 7, characterized in that in step 2) , the magnetic powders prepared from step 1) are cold pressed, and then hot pressed at a temperature of 550 ～ 850 ℃, preferably 600 ～ 700 ℃, under a pressure of 20 ～ 200 MPa, preferably 20 ～ 100 MPa, so as to obtain the green body.
  9. The method of any one of claims 6 to 8, characterized in that in step 3) , the green body prepared from step 2) is hot deformed at a temperature of 750 ～ 850 ℃, preferably 780 ～ 820 ℃, under a pressure of 20 ～ 250 MPa, preferably 20 ～ 200 MPa, so as to obtain the hot deformed magnet.
PCT/CN2017/085072 2017-05-19 2017-05-19 Hot deformed magnet, and a method for preparing said hot deformed magnet Ceased WO2018209681A1 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
JP2019563829A JP6865857B2 (en) 2017-05-19 2017-05-19 A hot-worked magnet and a method for manufacturing the hot-worked magnet.
PCT/CN2017/085072 WO2018209681A1 (en) 2017-05-19 2017-05-19 Hot deformed magnet, and a method for preparing said hot deformed magnet
EP17910333.8A EP3625807B1 (en) 2017-05-19 2017-05-19 Hot deformed magnet, and a method for preparing said hot deformed magnet
CN201780090979.8A CN110753978B (en) 2017-05-19 2017-05-19 Thermally deformable magnet and method for producing same

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2017/085072 WO2018209681A1 (en) 2017-05-19 2017-05-19 Hot deformed magnet, and a method for preparing said hot deformed magnet

Publications (1)

Publication Number Publication Date
WO2018209681A1 true WO2018209681A1 (en) 2018-11-22

Family

ID=64273192

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2017/085072 Ceased WO2018209681A1 (en) 2017-05-19 2017-05-19 Hot deformed magnet, and a method for preparing said hot deformed magnet

Country Status (4)

Country Link
EP (1) EP3625807B1 (en)
JP (1) JP6865857B2 (en)
CN (1) CN110753978B (en)
WO (1) WO2018209681A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110060834A (en) * 2019-05-16 2019-07-26 常州威斯双联科技有限公司 Magnetically soft alloy powder inhales wave plate, preparation method, electronic component and electronic equipment

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111326336B (en) * 2020-02-28 2021-06-22 大连理工大学 A preparation method of high coercivity rare earth permanent magnet integrating oscillating thermal deformation and infiltration
US12586700B2 (en) * 2021-02-08 2026-03-24 Korea Institute Of Materials Science Method for manufacturing anisotropic rare earth bulk magnet, and anisotropic rare earth bulk magnet manufactured thereby
CN115938771B (en) * 2021-11-05 2024-04-12 燕山大学 SmFe (zinc oxide) x M 12-x Preparation method of nanocrystalline permanent magnet material
CN117877826A (en) 2024-02-01 2024-04-12 烟台东星磁性材料股份有限公司 Neodymium-iron-boron magnet and preparation method thereof

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102189266A (en) * 2010-03-08 2011-09-21 Tdk株式会社 Manufacturing method of rare earth alloy powders and permanet magnet
CN102436887A (en) * 2011-12-19 2012-05-02 钢铁研究总院 Anisotropic nanocrystalline composite permanent magnetic material and preparation method thereof
CN102610347A (en) * 2012-03-15 2012-07-25 江苏东瑞磁材科技有限公司 Rare earth permanent magnet alloy material and preparation process thereof
CN102693799A (en) * 2012-06-12 2012-09-26 钢铁研究总院 Electromagnetically-solidified and hot-pressed nanocrystalline magnet of permanent magnet rapidly-quenched ribbon and preparation method of electromagnetically-solidified and hot-pressed nanocrystalline magnet
US20130093552A1 (en) * 2010-06-30 2013-04-18 Qingkai Wang Neodymium-Iron-Boron Magnet having Gradient Coercive Force and its Preparation Method
US20150364234A1 (en) * 2012-12-31 2015-12-17 Xiamen Tungsten Co., Ltd. Manufacturing method of rare earth magnet based on heat treatment of fine powder

Family Cites Families (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04143205A (en) * 1990-10-04 1992-05-18 Showa Denko Kk Manufacture of rare earth metal anisortopy permanent magnet powder
US5395462A (en) * 1991-01-28 1995-03-07 Mitsubishi Materials Corporation Anisotropic rare earth-Fe-B system and rare earth-Fe-Co-B system magnet
US5211766A (en) * 1992-01-21 1993-05-18 General Motors Corporation Anisotropic neodymium-iron-boron permanent magnets formed at reduced hot working temperatures
US5352301A (en) * 1992-11-20 1994-10-04 General Motors Corporation Hot pressed magnets formed from anisotropic powders
JPH10189320A (en) * 1996-12-25 1998-07-21 Daido Steel Co Ltd Anisotropic magnet alloy powder and method for producing the same
JPH11233323A (en) * 1998-02-13 1999-08-27 Daido Steel Co Ltd Method for producing anisotropic magnet material and method for producing bonded magnet using the same
FR2779267B1 (en) * 1998-05-28 2000-08-11 Rhodia Chimie Sa PROCESS FOR PREPARING A MAGNETIC MATERIAL BY FORGING AND MAGNETIC MATERIAL IN POWDER FORM
US6302939B1 (en) * 1999-02-01 2001-10-16 Magnequench International, Inc. Rare earth permanent magnet and method for making same
WO2004013872A1 (en) * 2002-08-05 2004-02-12 Santoku Corporation Permanent magnet and process for producing the same
JP4730545B2 (en) * 2006-04-14 2011-07-20 信越化学工業株式会社 Method for producing rare earth permanent magnet material
CN102640238B (en) * 2009-12-09 2015-01-21 爱知制钢株式会社 Rare earth anisotropic magnet and process for production thereof
JP5906874B2 (en) * 2011-03-28 2016-04-20 日立金属株式会社 Manufacturing method of RTB-based permanent magnet
JP5640946B2 (en) * 2011-10-11 2014-12-17 トヨタ自動車株式会社 Method for producing sintered body as rare earth magnet precursor
JP5752094B2 (en) * 2012-08-08 2015-07-22 ミネベア株式会社 Method for producing full-dense rare earth-iron bond magnet
JP2014170859A (en) * 2013-03-04 2014-09-18 Honda Motor Co Ltd Magnetic anisotropic magnet and manufacturing method thereof
CN104505207B (en) * 2014-12-15 2017-09-29 钢铁研究总院 Big L/D ratio radial hot pressing permanent-magnetic clamp and preparation method thereof
CN106448986B (en) * 2016-09-23 2018-05-11 四川大学 A kind of anisotropy nanocrystalline rare-earth permanent magnet and preparation method thereof

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102189266A (en) * 2010-03-08 2011-09-21 Tdk株式会社 Manufacturing method of rare earth alloy powders and permanet magnet
US20130093552A1 (en) * 2010-06-30 2013-04-18 Qingkai Wang Neodymium-Iron-Boron Magnet having Gradient Coercive Force and its Preparation Method
CN102436887A (en) * 2011-12-19 2012-05-02 钢铁研究总院 Anisotropic nanocrystalline composite permanent magnetic material and preparation method thereof
CN102610347A (en) * 2012-03-15 2012-07-25 江苏东瑞磁材科技有限公司 Rare earth permanent magnet alloy material and preparation process thereof
CN102693799A (en) * 2012-06-12 2012-09-26 钢铁研究总院 Electromagnetically-solidified and hot-pressed nanocrystalline magnet of permanent magnet rapidly-quenched ribbon and preparation method of electromagnetically-solidified and hot-pressed nanocrystalline magnet
US20150364234A1 (en) * 2012-12-31 2015-12-17 Xiamen Tungsten Co., Ltd. Manufacturing method of rare earth magnet based on heat treatment of fine powder

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP3625807A4 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110060834A (en) * 2019-05-16 2019-07-26 常州威斯双联科技有限公司 Magnetically soft alloy powder inhales wave plate, preparation method, electronic component and electronic equipment
CN110060834B (en) * 2019-05-16 2021-06-08 常州威斯双联科技有限公司 Soft magnetic alloy powder, wave absorbing plate, preparation method of soft magnetic alloy powder, electronic component and electronic equipment

Also Published As

Publication number Publication date
JP6865857B2 (en) 2021-04-28
EP3625807B1 (en) 2021-03-24
JP2020520414A (en) 2020-07-09
CN110753978A (en) 2020-02-04
CN110753978B (en) 2021-09-28
EP3625807A1 (en) 2020-03-25
EP3625807A4 (en) 2020-06-17

Similar Documents

Publication Publication Date Title
CN105355354B (en) A kind of samarium iron nitrogen base anisotropy rare earth permanent magnet powder and preparation method thereof
JP5767788B2 (en) R-T-B rare earth permanent magnet, motor, automobile, generator, wind power generator
CN103794322B (en) A kind of ultra-high coercive force sintered Nd-Fe-B magnet and preparation method thereof
JP7418598B2 (en) Heavy rare earth alloys, neodymium iron boron permanent magnet materials, raw materials and manufacturing methods
CN102959647B (en) R-T-B series rare earth permanent magnets, motors, automobiles, generators, wind power generation devices
JP6257890B2 (en) Permanent magnet and motor and generator using the same
JP5120710B2 (en) RL-RH-T-Mn-B sintered magnet
JP5472236B2 (en) Rare earth magnet manufacturing method and rare earth magnet
JP5692231B2 (en) Rare earth magnet manufacturing method and rare earth magnet
JP5163630B2 (en) Rare earth magnet and manufacturing method thereof
WO2018209681A1 (en) Hot deformed magnet, and a method for preparing said hot deformed magnet
CN102903471A (en) Neodymium-iron-boron permanent-magnet material and preparation method thereof
JP2011021269A (en) Alloy material for r-t-b-based rare-earth permanent magnet, method for manufacturing r-t-b-based rare-earth permanent magnet, and motor
JP2014101547A (en) Permanent magnet, motor and electric generator using the same
CN103153504B (en) Alloy material for R-T-B system rare earth permanent magnet, method for producing R-T-B system rare earth permanent magnet, and motor
WO2012029527A1 (en) Alloy material for r-t-b-based rare earth permanent magnet, production method for r-t-b-based rare earth permanent magnet, and motor
CN114156031B (en) Neodymium iron boron magnets and their preparation methods
CN105679479B (en) The preparation method of permanent-magnet material and permanent-magnet material
CN103258609A (en) Anisotropism nanometer rare earth permanent magnetic material and preparation method thereof
JP2007266199A (en) Manufacturing method of rare earth sintered magnet
JP2739525B2 (en) R-Fe-BC permanent magnet alloy with low irreversible demagnetization and excellent thermal stability
JP2024020341A (en) Anisotropic rare earth sintered magnet and its manufacturing method
JP2022068679A (en) Rare-earth magnet and manufacturing method thereof
JP2002285276A (en) RTBC based sintered magnet and method of manufacturing the same
JP2013098319A (en) METHOD FOR MANUFACTURING Nd-Fe-B MAGNET

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 17910333

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2019563829

Country of ref document: JP

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

WWE Wipo information: entry into national phase

Ref document number: 2017910333

Country of ref document: EP

ENP Entry into the national phase

Ref document number: 2017910333

Country of ref document: EP

Effective date: 20191219