6_Pop-Chicinas_Seminar Nano 3 02 2010_Bucuresti

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