1. Nanostructured Rare-Earth Transition-Metal Permanent Magnets
Paul McGuiness
Department for Nanostructured Materials
Jožef Stefan Institute, Ljubljana, Slovenia
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2. Introduction H2 Permanent-magnet (PM) materials Magnetic properties
PM applications
Nano melt-spun magnets
Nano HDDR magnets
Summary H2
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3. Womeninnano winter school
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4. Magnetic properties Ms Br BH max Hci Hcb -H +H Permanent-magnet
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5. 280 years of progress lodestone (1724) neodymium iron boron (2006)
ferrite
(1950)
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6. Improved properties over time
NdFeB
50 MGOe
Sm2Co17
+ price
+ mechanical
+ temperature
+ history
Sm2Fe17N3
SmCo5
AlNiCo
steel
Ferrite
1900
1950
2000
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7. Improved properties over time
1.4
Sintered NdFeB
1.2
Bonded nano
HDDR NdFeB
Alnicos
1.0
0.8
Bonded SmCo
Br (Tesla)
0.6
0.4
(Bonded nano MQ NdFeB)
Sintered Ferrite
0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
Hcj (MA/m)
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8. 2008 Lexus RX Hybrid Automotive apps
1118 magnets (inc. 2.9kg of Nd-Fe-B)
1998 Toyota Celica GT
has 543 magnets
1987 Yugo 45 (GV)
has 9 magnets
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9. Computer apps Fujitsu 300 GB 2.5" SATA Hard Disk Drive
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10. Other apps Womeninnano winter school
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11. Who makes RE-TM magnets?
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12. Processing Nd15Fe77B8-type materials
Nd15Fe77B8 - the cast alloy
Nd15Fe77B8 - the magnet
50 micron
50 micron
NdFe4B4
Nd2Fe14B
Nd2Fe14B
Nd-rich
Nd-rich
Nd2Fe14B Ms = 1.6 Tesla
Ha = 5 MA/m
Tc = 320°C
Nd-rich phase
MP = ~630°C
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13. Processing Nd15Fe77B8-type materials
Casting
Sintered magnets
Vacuum sintering
Attritor milling
Melt spinning
Ribbons
HDDR process
Powder
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14. Processing Nd15Fe77B8-type by melt spinning
alloy
Melt spinner
~600 deg C
crystalline
ribbons
Over-quenched
amorphous ribbons
die-upset magnet
(aniso)
hot-pressed magnet
(iso)
bonded magnet
(iso)
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15. Processing Nd15Fe77B8-type by melt spinning
Die upset
(fully dense
anisotropic)
Hot pressed
(fully dense
isotropic)
Injection moulded
(not fully dense
isotropic)
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16. Processing Nd15Fe77B8-type by melt spinning
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17. Processing Nd15Fe77B8-type by HDDR process
Nd-rich
Nd-hydride
NdH2
+ Fe
+Fe2B
Nd2Fe14B H2
750 degC
Isotropic and
anisotropic forms
are possible with
small additions of
Zr and Ga
Nd2Fe14B
vac
650 degC
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18. Processing Nd15Fe77B8-type by HDDR process
10 microns
Anisotropic structure that can
be aligned to produce
anisotropic bonded magnets
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19. Properties of NdFeB magnets
aniso melt-spun die upset
anisotropic
sintered
1 T
iso HDDR bonded
iso melt-spun
hot pressed
magnetisation
iso melt-spun injec
mould
iso HDDR injec mould
coercivity
1000 kA/m
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20. Summary RE-TM magnets have a wide range of applications
Properties depend on materials and processing
A nano grain size and good microstructure is vital for good properties
Good properties can be achieved with a range of techniques
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