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Nanocrystalline/nanostructured magnetic materials obtained by mechanical alloying/milling
mechanical alloying: powder alloying by high energy milling; it results new phases
mechanical milling: powder milling without producing chemical reactions; conservation of the initial phases.
V. POPFaculty of Physics, Babes-Bolyai University, 400084 Cluj-Napoca, Romania
I. CHICINAŞMaterials Sciences and Technology Dept., Technical University of Cluj-Napoca, 103-105 Muncii ave., 400641 Cluj-Napoca, Romania
nanostructuredhardandsoft
magnetic materials
ANNEALING modifiesthe structure and microstructure
Nanocrystalline materials (d < 100 nm) obtained by:
• vapour - inert gas condensation, sputtering, plasma processing, vapour deposition • liquid - electrodeposition, rapid solidification• solid - mechanical alloying, severe plastic deformation, spark erosion
µ >> 0magnetic coresmagnetic circuits
soft
Hc – SMALL~0,001÷10 A/m
permanentmagnets
hard
Hc – HIGH ~102÷106 A/m
mechanical alloying,mechanical milling
I. Hard Magnetic Nanostructured Materials:hard/soft nanocomposite exchange spring magnets
• Babes-Bolyai University Cluj NapocaViorel Pop
II. Soft Magnetic Nanocrystalline Materials•Technical University of Cluj-Napoca, Romania
Ionel ChicinaşNational partnersin research projects as RELANSIN, MATNANTECH, CERES, from PNCDI II, etc
Partners: INCDFM Bucharest (M. Valeanu), ICPE-CA Bucharest (W. Kappel), INCDTIM Cluj (O. Pana), Univ. Al. I. Cuza Iasi (A. Stancu), INCDFT-IFT Iasi (H. Chiriac).
European partnersNéel Institute and University Joseph Fourier Grenoble, University of Rouen,
University of Nantes, Chemnitz University, CNRS Toulouse
5 PhD thesis connected to these subjects
•milling of the powders in a high energy planetary mill•heat treatments (temperatures and duration)
Material preparation
Starting materials: • hard magnetic phases :
SmCo5, SmCo3Cu2, R2Fe14Bingots – prepared by melting
• Soft magnetic phases:Fe NC 100.24 powder (Höganäs), (< 40 μm), 123-carbonil nickel (5-7 μm), NC 100.24 (Hoganas) Fe powders, (< 40 μm) Mo powder (Sinterom SA) (<10 μm), Cu powder (Tehnomag SA)
Mechanical milling • in Ar atmosphere for 1.5 – 52 h
Annealing: • in vacuum/450-800 °C for 5 min. up to 10 hours
•X-rays diffraction (XRD)•Electron microscopy (SEM and TEM)
morphologychemical composition checked by EDX
•DTA, DSC•Magnetic measurements•Mössbauer spectrometry
Material characterisation
I. Hard Magnetic Nanostructured Materials:hard/soft nanocomposite exchange spring magnets
high anisotropy
large magnetization
+
hard phase
exchange
soft phase
Exchange spring magnets
-120
-80
-40
0
40
80
120
-6 -4 -2 0 2 4 6
SmCo5+20%Fe
T = 4 K
M (e
mu/
g)
µ0H (T)
SmCo5
Fe
0H ≠r
0H =r
SmCo5
Fe
θ
Large reversible demagnetization curve+
Enhanced remanence mr > 0.5 (mr = Mr/Ms)
a magnetit magnet (1750)
A ferrite magnet (1940)
rare earth based magnet (1980)
All this magnets have the same energy !
10 cm
exchange-spring magnets (2???)
Kronmuller & Coey Magnetic Materials, in European White book
on Fundamentel Research in Materials Science
Max Planck Inst. Metallforschung,Stuttgart, 2001, 92-96
(BH)max = 1090 kJ/m3 for nanostructured multilayers Sm2Fe17N3/Fe65Co35R. Skomski, J. Appl. Phys. 76 (1994) 7059
Theoretical predictions:
Experimental realisations: ??????????
Best magnets on the market:(BH)max ≈ 500 kJ/m3
SmCo5 + α-FeSmCo3Cu2 + α-FeR2Fe14B + α-Fe
Mechanical milling+
annealing
InterInter--phase Exchange coupling phase Exchange coupling Hard/Soft nanocomposites magnetic materialsHard/Soft nanocomposites magnetic materials
SmCo5+20 wt% FeSmCo5 MM2h et SmCo5+20%Fe MA 2 - 8h
27-1122 (C) - Cobalt Samarium - Co5Sm - Y: 35.22 % - d x by: 1. - WL: 1.5406 - Hexagonal - a 4.997 - b 4.87-0721 (C) - I ron - Fe - Y: 57.23 % - d x by: 1. - WL: 1.5406 - Cubic - a 2.86620 - b 2.86620 - c 2.86620 - Operations : Smooth 0.150 | Y Scale Add -4729 | ImportSmCo5+20%Fe/2h MA - File: SmCo5_2hMM.RAW - Type: PSD fast-scan - Start: 25.000 ° - End: 85.828 °
Operations: Smooth 0.150 | Y Scale Add -4500 | ImportSmCo5+20%Fe/2hMA - File: SmCo5_20Fe2hMA.RAW - Type: PSD fast-scan - Start: 25.000 ° - End: 90.12Operations: Smooth 0.150 | Y Scale Add -4271 | ImportSmCo5 + 20%Fe 4hMA - File: SmCo5_20Fe4h.RAW - Type: PSD fast-scan - Start : 25.000 ° - End: 90.123 Operations: Smooth 0.150 | Y Scale Add -4500 | ImportSmCo5+20%Fe/6hMA - File: SmCo5_20Fe6h.RAW - Type: PSD fast-scan - Start: 25.000 ° - End: 90.123 °Operations: Smooth 0.150 | Y Scale Add -4042 | Y Scale Mul 6.333 | Importd:\users\invite\D5000_data\SmCo5_20Fe_8hMA.RAW - File: SmCo5_20Fe8hMA.RAW - Type: PSD fast-s
Inte
nsity
2 Theta (deg)30 40 50 60 70 80 90
8h MM
6h MM4h MM2h MM
SmCo5/2h MM
30 40 50 60 70 80 90| Fe main peaks| SmCo5 main peaks
2 θ (o)Annealed samples
As milled samples
2 T h e ta ( d e g r e e s )2 8 3 0 4 0 5 0 6 0 7 0 8 0
30 40 50 60 7080
2 θ (°)
10h MM+550°C/1.5h
8h MM+550°C/1.5h8h MM
6h MM+550°C/1.5h6h MM
SmCo5/2h MM
Sm2O3
SmCo5
α-Fe
Inte
nsity
V. Pop, O. Isnard, I. Chicinas, D. Givord, J.M. Le Breton, J. of Optoelectron. Adv. Mater. 8 (2006) 494.D. Givord, O. Isnard, V. Pop, I. Chicinas, J. Magn. Magn. Mater. 316 (2007) e503–e506
SEM – EDX → composition homogeneity of SmCo5 +20% Fe 2h MM
SEM – EDX → composition homogeneity of SmCo5 +20% Fe 8h MM
8 h milled sample annealed at 550 °C
SEM: SmCo5 + 20% α-Fe Milling time ◄► Composite homogeneity
SmCo5/α-Fe
6 h milled samples annealed at 600 °C
SmCo5
TEM
5 nm
2 T h e ta
2 8 3 0 4 0 5 0 6 0 7 0 8 0
30 40 50 60 70 802 θ (°)
Inte
nsity
8h +650°C/0.5h8h +600°C/0.5h 8h +550°C/1.5h8h +500°C/1.5h8h +450°C/0.5h8h MM
Sm2O3Fe
SmCo5
For 6 h or more MM sample D < 30 nm
SmCo5 + 20% α-Fe Milling+ ◄► Crystallites dimensionAnnealing
XRD:
6h MM+450 ºC/0.5h
36.633.533.2800 (5 min)
26.429.424.4650 (1.5 h)
--21.6600 (1.5 h)
16.217.720.3550 (1.5 h)
(Nd0.92Dy0.08)2Fe14B/α-Fe-6hMM
(nm)
(Pr0.92Dy0.08)2Fe14B/α-Fe-12hMM
(nm)
(Pr0.92Dy0.08)2Fe14B/α-Fe-6hMM
(nm)
AnnealingTemperature(°C)/(time)
Fe crystallite size from XRD
Velocity ( mm / s )
0-11 +11
Echantillon avant broyage
6h/1.5 à 450°C
6h/10h à 450°C
8h/10h à 450°C
0.90
1.00
Abs
orpt
ion
( %
)
0.92
1.00
Abs
orpt
ion
( %
)
0.99
1.00
Abs
orpt
ion
( %
)
0.99
1.00
Abs
orpt
ion
( %
)
Sm(Co,Fe)x
Fe(Co)
Starting sample
6h MM+ 450ºC/1.5h
6h MM+ 450ºC/10h
8h MM+ 450ºC/10h
Velocity (mm/s)-11 0 11
1.00
0.901.00
0.921.00
0.991.00
0.99
Abs
orpt
ion
(%)
Velocity ( mm / s )
0-11 +11
Echantillon avant broyage
6h/1.5 à 450°C
6h/10h à 450°C
8h/10h à 450°C
0.90
1.00
Abs
orpt
ion
( %
)
0.92
1.00
Abs
orpt
ion
( %
)
0.99
1.00
Abs
orpt
ion
( %
)
0.99
1.00
Abs
orpt
ion
( %
)
Sm(Co,Fe)x
Fe(Co)
Starting sample
6h MM+ 450ºC/1.5h
6h MM+ 450ºC/10h
8h MM+ 450ºC/10h
Velocity (mm/s)-11 0 11
1.00
0.901.00
0.921.00
0.991.00
0.99
Abs
orpt
ion
(%)
α-Fe phase contribution, with the possible insertion of Co in Fe structure, named α-(Fe,Co) phasethe second one, different to α-Fe, is given by a Sm(Co,Fe)5
0
10
20
30
40
50
60
70
80
90
100
0 2 4 6 8 10
Durée du broyage (h)In
tens
ité re
lativ
e (%
)
α-(Fe,Co)
Sm(Co,Fe)5
SmCo5 + 20% α-Fe Fe Mössbauer spectroscopy: Co in Fe and Fe in SmCo5 ?
V. Pop, O. Isnard, I. Chicinas, D. Givord, J.M. Le Breton, J. of Optoelectron. Adv. Mater. 8 (2006) 494.J.M. Le Breton, R. Lardé, H. Chiron, V. Pop, D. Givord, O. Isnard, I. Chicinas, J. Phys. D: App.Phys. (2010)
-100
-50
0
50
100
-3 -2 -1 0 1 2 3
SmCo5+20%Fe
2h MM4h MM6h MM8h MMSmCo
5/2h MM
M (e
mu/
g)
H (T)
-100
-50
0
50
100
-3 -2 -1 0 1 2 3
SmCo5+20%Fe
MM + annealing
2h MM+450oC0.5h
4h MM+450oC0.5h
6h MM+450oC0.5h
8h MM+450oC0.5hSmCo
5/2h MM
M (e
mu/
g)
H (T)
as m
illed
sam
ples
milled and annealed
The coercivity and the remanence highly increase with the heat treatment compared to the as milled samples.
the influence of the
annealing
V. Pop, O. Isnard, I. Chicinas, D. Givord, J.M. Le Breton, J. of Optoelectron. Adv. Mater. 8 (2006) 494.
-100
-50
0
50
100
-4 -3 -2 -1 0 1 2 3 4
SmCo5 + 20Fe/8h MM
as milled
450oC 0.5h
500oC 1.5h
550oC 1.5h
600oC 0.5h
650oC 0.5hSmCo
5/2h MM
M (e
mu/
g)
H (T)
0
50
100
150
200
250
-3 -2.5 -2 -1.5 -1 -0.5 0 0.5 1
SmCo5+20 wt% Fe
T = 300 K
8hMM+450oC/0.5h
8hMM+450oC/10h
dM/d
H (A
m2 /k
gT)
μ0H (T)
0.63 T0.43 T
0
50
100
150
200
250
300
350
400
-3 -2.5 -2 -1.5 -1 -0.5 0 0.5 1
SmCo5+20 wt% Fe_
8hMM
8hMM+450oC/0.5h
8hMM+500oC/1.5h
8hMM+550oC/1.5h
8hMM+600oC/0.5h
8hMM+650oC/0.5h
dM/d
H (A
m2 /k
gT)
μ0H (T)
annealing time
exchange coupling
annealing temperature
exchange coupling
-100
-50
0
50
100
-2 -1.5 -1 -0.5 0 0.5 1 1.5 2
SmCo5+20wt%Fe
M (Am^2/kg)_800/1%M (Am^2/kg)_600/1%M (Am^2/kg)_700/0.5%M(A*m^2/kg)/magnetic powder
M (A
m2 /k
g)
µ0H (T)
isotropic bonded magnets ↔ magnetic powder
Research in progress:
Obtaining of bulk spring magnets by SPARK PLASMA SINTERINGfrom mechanically milled powders
II. Soft Magnetic Nanocrystalline Materials
soft magnetic nanostructures
low coercivity and high permeability
small ferromagnetic crystallites coupledby exchange interactions
The local anisotropies are randomly averaged out by exchange interactions so that there is no anisotropy net effect on the magnetisation process.
Lex
D
Random Anisotropy Model: D < Lex*
Grain size, D(nm)10 100 1000
* G. Herzer, IEEE Trans. Magn. MAG-26 (1990) 1397R. Alben, J.J. Becker, M.C. Chi, J. Appl. Phys, 49 (1978) 1653
0 10 20 30 40 50 60 70 80 90 10
200
800
600
400
γ-fcc
α-b
cc
Ni3Fe
Fe NAtomic percent Nickel
Tem
pera
ture
(°C
) bcc+
fcc
bcc
bcc+
fcc
bct fcc
40%
[86,
99]
50%
[86,
96,
100
]
60%
[86]
70%
[86]
80%
[86,
115
]
90%
[86]
[106, 107, 96, 104,
112, 101, 103, 114]
38%
[86]
36%
[86]
34%
[86]
32%
[86]
30%
[86,
100]
28%
[86]
26%
[86]
22%
[86]
11.1
1% [8
4]
20%
[96,
86]
14.4
% [9
4]
9.09
% [8
4]7.
69%
[84]
10% [86]
24.1% [97]
75%
bcc+
fcc
bct[
97] bc
t
bct+
fcc
[98]
19.2
% [9
3, 9
7]
9.6% [93]
24%
[86]
29% [97, 98]
33.9% [97, 98]
35% [96, 99]
bcc+
fcc
[99,
100
]
bcc+
fcc
[99]
27,5% [99]25% [99]22.5% [99]
85%
[93]
0 10 20 30 40 50 60 70 80 90 100 10 20 30 40 50 60 70 80 90 10
200
800
600
400
γ-fcc
α-b
cc
Ni3Fe
Fe NAtomic percent Nickel
Tem
pera
ture
(°C
) bcc+
fcc
bcc
bcc+
fcc
bct fcc
40%
[86,
99]
50%
[86,
96,
100
]
60%
[86]
70%
[86]
80%
[86,
115
]
90%
[86]
[106, 107, 96, 104,
112, 101, 103, 114]
38%
[86]
36%
[86]
34%
[86]
32%
[86]
30%
[86,
100]
28%
[86]
26%
[86]
22%
[86]
11.1
1% [8
4]
20%
[96,
86]
14.4
% [9
4]
9.09
% [8
4]7.
69%
[84]
10% [86]
24.1% [97]
75%
bcc+
fcc
bct[
97] bc
t
bct+
fcc
[98]
19.2
% [9
3, 9
7]
9.6% [93]
24%
[86]
29% [97, 98]
33.9% [97, 98]
35% [96, 99]
bcc+
fcc
[99,
100
]
bcc+
fcc
[99]
27,5% [99]25% [99]22.5% [99]
85%
[93]
Ni3FeSupermalloy (9Ni16Fe5Mo , 77Ni14Fe5Cu4Mo, wt%)
Rhometal (64Fe36Ni, wt%)Hipernick (50Fe50Ni wt%)Mumetal (76Ni17Fe5Cu2Cr, wt%)
In progress
It is possible to combine the properties of Ni-Fe and Ni-Fe-X-(Y) systems with the properties of nanocrystalline state
Why Ni-Fe and Ni-Fe-X-(Y) systems?
Polycrystalline Ni-Fe and Ni-Fe-XAlloys have very good SMP
Why mechanical alloying techniques?
I. Chicinaş, , J. Optoelectron. Adv. Mater. 8 (2006), 439-448V. Pop, I. Chicinaş, J. Optoelectron. Adv. Mater. 9 (2007), 1478-1491
SM powders produced by MA in Ni-Fe system
II. Soft Magnetic Nanocrystalline Materials
Nanocrystalline materials havevery good SMP
Ni3Fe
Ni
Inte
nsité
(u.a
.)
2 t h e t a8 9 . 2 9 0 9 1 9 2 9 3 9 4 9 5
1h1h+ 330°C/1h2h2h+ 330°C/1h3h3h+ 330°C/1h4h4h+ 330°C/1h6h6h+ 330°C/1h8h8h+ 330°C/1h10h10h+ 330°C/1h12h12h+ 330°C/1hss
90 91 92 93 94 95
2 θ (°)
Inte
nsity
(a.u
.)
ss1h1h+330°C/1h2h2h+ 330°C/1h3h3h+330°C/1h
4h4h+330°C/1h6h6h+330°C/1h
8h8h+330°C/1h10h10h+330°C/1h12h12h+330°C/1h
Inte
nsité
(uni
t. ar
b.)
2 theta (degrés)36 40 50 60 70 80 9040 50 60 70 80 90
2 θ (°)
Inte
nsity
(a.u
.)
Fe Fe
Ni3Fe
Ni
peaks shift to lower 2θ angles
peaks shift to HIGHER 2θ angles
broadening of the diffraction peaks
•Ni3Fe phase formation•the first order internal stresses
relaxation of the first order internal stresses
the second order internal stresses
decreasing of the crystallites dimension
Ni3Fe
(311)
The particles morphology of the Ni3Fe powders
after 12h mechanical alloying.
SEM
II. Soft Magnetic Nanocrystalline Materials
4.0
4.1
4.2
4.3
4.4
4.5
4.6
4.7
0 0.5 1 1.5 2 2.5 3 3.5
M (µ
B/f.
u.)
annealing time(hours)
T = 4 K
ss
1 h
2 h
3 h
4 h
6 h
8 hx 10 ho 12 h
V. Pop, O. Isnard and I. Chicinas, J. Alloys and Comp., 361 (2003), p.144-152.
3.8
3.9
4.0
4.1
4.2
4.3
4.4
4.5
0 10 20 30 40 50 60
4 K295 K
Ms (µ
B/f.
u.)
Tem ps de broyage (h)
recuit
I. Chicinas, V. Pop and O. Isnard, J. Magn. Magn. Mater. 242-245 (2002) p. 885-887
II. Soft Magnetic Nanocrystalline Materials
Fe1-xNixin the reach nickel region*
x MFe and MNi=ct.
MNi-Fe when Ni3Fe %
*H. Hasegawa, J. Kanamori, J. Phys. Soc. Jap. 33 (1972) 1599
Magnetic measurements
0
20
40
60
80
100
0 10 20 30 40 50 60In
tens
ité M
ossb
auer
(%)
Temps de broyage (h)
Ni3Fe
α-FeMös
sbau
er in
tens
ity (%
)
milling time (hours)
Mössbauer spectrometryNi3Fe powders
I. Chicinas, V. Pop, O. Isnard, J.M. Le Breton and J. Juraszek, J. Alloys and Compounds 352 (2003), p. 34-40
II. Soft Magnetic Nanocrystalline Materials
3 .8
3 .9
4 .0
4 .1
4 .2
4 .3
4 .4
4 .5
0 10 20 30 4 0 50 60
4 K295 K
Ms (µ
B/f.
u.)
T em ps de b roy age (h )
recu it
0h
3h
4h
8h
10h
12h
Velocity ( mm / s )
0-10 +10
0.96
1.00
Absorption ( %
)
0.96
1.00
Absorption ( %
)
0.97
1.00
Absorption ( %
) 0.98
1.00
Absorption ( %
)
0.99
1.00
Absorption ( %
)
0.98
1.00
Absorption ( %
)
16h
24h
40h
48h
52h
52hannealed
Velocity ( mm / s )
0-10 +10
0.99
1.00
Absorption ( %
)
0.99
1.00
Absorption ( %
)
0.98
1.00
Absorption ( %
) 0.98
1.00
Absorption ( %
)
0.98
1.00
Absorption ( %
)
0.98
1.00
Absorption ( %
)
Speed (mm/s)-10 0 +10
Speed (mm/s)-10 0 +10
Abs
orpt
ion
(%)
Abs
orpt
ion
(%)
300 500 700 900 1100Temperature (K)
TC
Ni
TC
NiFeCuMoT
C Fe
Temperature (K)
M² (
a.u.
) 10 h
4h
ss
AB
300 500 700 900 1100Temperature (K)
TC
Ni
TC
NiFeCuMoT
C Fe
Temperature (K)
M² (
a.u.
)
300 500 700 900 1100Temperature (K)
TC
Ni
TC
NiFeCuMoT
C Fe
Temperature (K)
M² (
a.u.
) 10 h
4h
ss
AB
thermomagnetic analysis
SS : start mixture: Tc of Ni and Fe
4h : - by heating, point A correspond to Tc of NiFeCuMo obtained by milling
- progressive formation of the alloys byheating, B region.
-at cooling, only one magnetic phase, Tc
10h : one Tc is observed by heating
77Ni14Fe5Cu4Mo wt%
Température en K
F. Popa, O. Isnard, I. Chicinas, V. Pop, J. Magn. Magn. Mater., 316 (2007) e900–e903 F. Popa, O. Isnard, I. Chicinas, V. Pop, J. Magn. Magn. Mater., (2010) in press
Some results
0.0
2.0
4.0
6.0
8.0
10.0
12.0
0 0.5 1 1.5 2 2.5 3
mill
ing
time
(hou
rs)
annealing time (hours)
0.0
2.0
4.0
6.0
8.0
10.0
12.0
0 0.5 1 1.5 2 2.5 3
mill
ing
time
(hou
rs)
annealing time (hours)
Ni Fe3
M = const.s
Ni+Fe+Ni Fe (Ni-Fe) 3
330 C o
T >330 C1 o
T >T2 1
Milling – Annealing - Transformation (MAT) diagram
Mechanical Alloying and Annealing Combining technique
V. Pop, O. Isnard and I. Chicinas, J. Alloys and Comp., 361 (2003), p.144-152.
milling time–annealing timecombination required to obtain the Ni3Fe phase in the whole sample
II. Soft Magnetic Nanocrystalline Materials
Soft magnetic nanocrystalline composites
Ni3Fe
polymer layer
+polymer
dissolvingNi3Fenano
covered powder (1, 1.5, 2, 3 wt%)
Die pressed (600 - 800 MPa )
Polymerisation(60 min., 180 oC)
Composites Production
I. Chicinaş, O. Isnard, O. Geoffroy, V. Pop, J. Magn. Magn. Mater. 290-291 (2005), 1531-1534 I. Chicinaş, O. Isnard, O. Geoffroy, V. Pop, J. Magn. Magn. Mater. 310 (2007), 2474-2476
16
18
20
22
24
26
28
30
0
100
200
300
400
500
600
0 20 40 60 80 100
µ; Ni3Fe; B=0.05 Tµ; NiFe; B=0.05 Tµ; Ni3Fe; B=0.1Tµ; NiFe; B=0.1Tµ; Ni3Fe; B=0.2Tµ; NiFe; B=0.2T
P/f; Ni3Fe; B=0.05 TP/f; NiFe; B=0.05 TP/f; Ni3Fe; B=0.1 TP/f; NiFe; B=0.1 TP/f; Ni3Fe; B=0.2 TP/f; NiFe; B=0.2 T
µ
P/f (
J/m
3 )
f (kHz)
Some results
Research in progress:
Obtaining of nanocrystalline compacts by SPARK PLASMA SINTERINGfrom mechanically alloyed powders
Thank you
Mulţumesc
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