New 3-D Bulk Shaped Polycrystalline and Nanocomposite...

European School on Magnetism / Workshop on Advanced Magnetic MaterialsSeptember 9-18, 2007 ● Cluj-Napoca, Romania

New 3-D Bulk ShapedPolycrystalline and Nanocomposite

Magnetostrictive Materials*

N. Lupu #, H. ChiriacG. Ababei, M. GrigorasM. Valeanu

T. Buruiana,V. HarabagiuI. Mihalca

*This work was generated in the context of the MESEMA project (http://www.mesema.info), funded under the 6th Framework Programme of the European Community (Contract N° AST3-CT-2003-502915) and MAGSAT project (Contract No 34/2005) (http://www.phys-iasi.ro/ift/MAGSAT.htm) funded under CEEX Programme of the Romanian Ministry of Education and Research – National Authority for Scientific Research.#Address for correspondence: [email protected]

National Institute of R&D for Technical Physics, Iasi, RomaniaNational Institute of Materials Physics, Bucharest-Magurele, Romania“Petru Poni” Institute of Macromolecular Chemistry, Iasi, RomaniaCondensed Matter Research Institute, Timisoara, Romania


� Magnetostriction

OutlinesOutlines� Magnetic Sensors and Actuators vs. Smart Materials� Fe-(Ga,Al) magnetostrictive alloys� (Co,Ni)-Mn-(Ga,Al) magnetostrictive alloys� (Fe,Co)-RE-B magnetostrictive materials (RE = Tb, Dy, Sm)� Conclusions & Potential Applications


Magnetostrictive materials are changing their shape due to the change in the magnetization state of the material.

Although nearly all ferromagnetic materials exhibit a shape change resulting from magnetization change, only those with significant interactions between shape change and magnetization change are suitable for sensors/actuators applications.

Magnetostriction (1)Magnetostriction (1)


� Magnetostriction - a consequence of the magnetoelastic coupling.� Magnetostriction is an intrinsic property of magnetic materials, which

is for a crystalline material a direction dependent tensor λhkl mainly caused

by the orbital coupling of the magnetic moment.� Linear, , or volume magnetostriction .� Positive when the material is elongated and negative when is

contracted.


llδ VVδ


� Saturation magnetostriction (λs) - the magnetostrictive deformation of a

material increases with the applied magnetic field increase and reaches the

maximum value.� Isotropic magnetostriction = spontaneous deformation “e” is constant

in all crystallographic directions.� Anisotropic magnetostriction = the sign and value of deformation

depend on the crystallographic direction.



Magnetostriction Magnetostriction –– How to measure it (1)How to measure it (1)� The magnetostriction can be measured by direct and indirect methods.� Direct methods: with strain gauges, capacitance transducers or interferometers.� For crystalline materials the use of strain gauges is most common.� The most sensitive method is the capacitance method.� Disadvantages of direct methods: they require a special sample preparation and they do not deliver the “true” saturation magnetostriction.� Indirect methods: Becker-Kersten method and SAMR method (Small Angle Magnetization Rotation).� Becker-Kersten method - the magnetostriction is determined from the

stress dependence of the hysteresis loop.� SAMR - for soft magnetic ribbons/wires because of the special geometry. Beside the stress dependence of the hysteresis the SAMR method delivers very accurate results. This method can also be used from 4.2 K up to high temperatures.

C. Polak, Thesis, TU Wien, 1992.


Comparison of some methods to measure magnetostrict ion

Variation of SAMR method~ ±10-9IndirectTransverse susceptibility

High sensitivity, suitable for ribbons,

usable at all temperature to determine λs

~ ±10-9IndirectSAMR(Small AngleMagnetisationRotation)

Good for negative and very small value

of λs

~ ±10-8IndirectStressdependence ofhysteresis loop

Most sensitive method but also difficult

to carry out at high temperature

~ ±10-10DirectCapacitance

Determine λ// and λ┴ independently,

difficult to perform at high temperature

±1 x 10-6DirectStrain gauges

RemarksSensitivityMannerMethod

Magnetostriction Magnetostriction –– How to measure it (2)How to measure it (2)


� Both magnetic sensor and actuator materials require strong interaction between the magnetic response and other responses to external factors (resistance, stress, strain, etc.).� Actuators materials are generally “hard” materials since significant stress is required for actuators to work.� Magnetic sensors materials can be “soft” materials, BUT high sensitivity and low noise level are important.� There is no clear “border” between magnetic sensors and actuators materials, and some actuator materials can be used as sensor materials as well.

Magnetic Sensors and Actuators vs. Smart Materials (1)Magnetic Sensors and Actuators vs. Smart Materials (1)


Magnetic Sensors and Actuators vs. Smart MaterialsMagnetic Sensors and Actuators vs. Smart Materials


Properties of Different Smart MaterialsProperties of Different Smart Materials

N/AMedium10-1004ElectroactivepolymerP(VDF-TrFE) N/AFast> 10000.12PiezoelectricPZT N/ASlow10-20> 5Shape Memory Alloy (SMA)Ni-Ti(Nitinol) ~380Fast> 505Ferromagnetic Shape Memory Alloy (FSMA)Ni-Mn-Ga ~923Fast< 150.013-0.025MagnetostrictorFe-Ga(Galfenol) 660Fast< 150.14-0.2MagnetostrictorKelvinAll®(EMERGEN) 653Fast< 150.16-0.24MagnetostrictorTb0.3Dy0.7Fe1.9(Terfenol-D) Curie Temperature (K)Relative Response SpeedActuation Voltage (V)Maximum Strain (%)Material TypeMaterial


� The fabrication of highly efficient integrated magnetostrictive sensors,

actuators and transducers requires the availability of magnetoelastic

materials with high magnetostriction and low saturation fields in different

shapes, depending on the final application.� Terfenol-D is the most used magnetostrictive material for

magnetostrictive actuators and transducers;� magnetostrictive metallic glasses are preferred for sensors applications;

Magnetic Sensors and Actuators vs. Smart MaterialsMagnetic Sensors and Actuators vs. Smart Materials


Magnetostrictive Materials Magnetostrictive Materials –– TERFENOL AlloysTERFENOL Alloys

The highest room temperature magnetostriction of a pure element is Co, which saturates at 60 ppm.

TERFENOL-D: Courtesy of ETREMA Inc.


Magnetostrictive Materials Magnetostrictive Materials -- METGLASMETGLAS

METGLAS (Fe-based alloy), discovered in early 1980s, is a good sensor material with an amorphous structure.

Why amorphous? The amorphous structure of METGLAS makes it have a smaller anisotropy energy compared with magnetocrystalline materials.

Annealing METGLAS in a magnetic field produces a well-defined anisotropy direction but with the smallest possible magnitude of anisotropy energy.

Magnetic moments rotate, without any domain wall motion.


D = dλ/dH - the rate at which the strain is developed with respect to the applied field.

H. Chiriac et al., Sensors and Actuators 81 (2000) 166.

Ferromagnetic METGLAS can effectively increase magnetostriction than crystalline materials, at the same magnetic field level.

Magnetostrictive Materials Magnetostrictive Materials -- METGLASMETGLAS


TERFENOL

1. Cubic C15 structure

2. Large magnetostrictive strains of the order of 0.1 % at and above RT

3. Brittle, large field for saturation,

expensive Tb and Dy

METGLAS

1. Amorphous

2. Low saturation magnetostriction

(30 x 10-6 for Fe81B13.5Si3.5C2)

3. Low field for saturation, large magnetomechanical coupling coefficient

New materials to combine the advantages of both materials.

Magnetostrictive MaterialsMagnetostrictive Materials

Very recently, 2 new alternatives appeared:� Fe-(Ga,Al) alloys, as single crystals and melt-spun ribbons� Ni-Mn-Al and Co-based magnetic shape memory alloys (MSMs)


Fe-(Ga,Al) system

(Galfenol Alloys)

“GALFENOL is the latest magnetostrictive material to be invented, and is currently under development. Originally invented in 1998 by the Magnetic Materials Group at NSWC-CD, GALFENOL is slowly emerging into the real world. While its magnetostriction is only 1/3rd to 1/4th that of Terfenol-D, GALFENOL is a much more robust material allowing it to be used in harsh mechanically harsh environments with minimal shock hardening.” (ETREMA Products, Inc. website)


3D3D--Bulk Shaped Samples PreparationBulk Shaped Samples Preparation

Magnetostriction measured by the electrical resistance strain gauge technique.

3-D shaped Fe100-x(Ga,Al)x polycrystalline magnetostrictive alloys (x = 13÷30) as thin plates of 12*6*0.5 mm and 40*5*1 mm, rods (6 mmφ and 40 mm long) and bars 3*3*10 mm3.


MeltMelt --Spun Ribbons PreparationSpun Ribbons Preparation� Ribbon samples were produced by melting 3 grams of ingot with an induction coil in a partial argon atmosphere and ejecting the melt onto a rotating copper wheel at a wheel speed of 35 m/s.� Isothermal heat treatment was performed on some ribbon samples at 10000C for 72 hours and then:� slow quenched to RT, OR� slow quenched to 8000C, then water

quenched.� Ribbons were evacuated in a quartz tube and then sealed with approximately one atmosphere of argon at the annealing temperature.


StructureStructure

The XRD patterns of as-quenched melt-spun ribbons and bulk shaped samples don‘t show any texture.

In addition, to the primary reflection at ~ 440 (110) and ~ 640 (200), none reflections corresponding to the DO3 phase are observed.

Fe-Ga19.5Fe-Ga22.5

Lin

(Cou

nts)

0

10 0

20 0

30 0

40 0

50 0

60 0

70 0

80 0

90 0

10 00

11 00

12 00

13 00

14 00

15 00

2-Th eta - S cale

3 1 40 50 6 0 70 8 0

FeFe-Ga17.5

Melt-spun ribbonsFe-Ga15

Lin

(Cou

nts

)

0

10

20

30

40

50

60

70

80

90

10 0

11 0

12 0

13 0

14 0

15 0

16 0

17 0

18 0

19 0

20 0

21 0

22 0

23 0

24 0

25 0

26 0

27 0

28 0

2-T h eta - S ca le

31 40 50 60 70 8 0

FeFe-Ga19.5

Cast bars 3 x 3 x 10 mm3Fe-Ga17.5

Investigated using both the conventional X-ray diffractometer and the high energy X-rays synchrotron radiation (ID11 @ ESRF Grenoble)


-0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8-200

-150

-100

-50

0

50

100

150

200

As-cast samples Fe

83Al

17

Fe83Ga

17

Fe79Al

21

Fe79Ga

21

Fe87Al

9Ga

4

Mag

netiz

atio

n (A

m2 /k

g)

Applied Field (T)

M-H loops of Fe-Ga, Fe-Al and Fe-Ga-Al thin plates (12*6*0.5 mm)in the as-cast state.

-0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8-200

-150

-100

-50

0

50

100

150

200

Thin plates - 12*6*0.5 mm - as-cast Fe

83Al

17

Fe79Al

21

Fe75Al

25

Fe70Al

30

Mag

netiz

atio

n (A

m2 /k

g)

Applied Field (T)

Magnetic BehaviorMagnetic Behavior


MM--T and MT and M--H curvesH curves

0 100 200 300 400 500 600 700 8000

20

40

60

80

100

120

140

160

180

M

agne

tizat

ion

(Am

2 /kg)

T (0C)

Fe1-x

Gax melt-spun ribbons

(vrotating wheel

= 35 m/sec) x = 0.175 x = 0.195 x = 0.21

Heating rate = 200C/min

-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0

-150

-100

-50

0

50

100

150

Mag

netiz

atio

n (A

m2 /k

g)

Applied field (T)

Fe1-x

Gax melt-spun ribbons

(vrotating wheel

= 35 m/sec)(as-quenched state)

x = 0.175 x = 0.195

The thermomagnetic measurements confirm the existence of bcc Fe (A2 phase), with an additional magnetic transition at around 5000C for Fe79Ga21melt-spun ribbons.

Very soft magnetic materials.


0.2 0.3 0.4 0.5 0.6 0.7 0.825

30

35

40

45

50

55

60

65

Fe83

Ga17

Fe79

Al21

Fe75

Al25

Fe70

Al30

λ s (pp

m)

Applied Field (T)

Magnetostriction versus applied magnetic field for Fe-Ga and Fe-Al thin plates (12*6*0.5 mm).

)(32

// ⊥−= λλλs

MagnetostrictionMagnetostriction


Magnetostriction as a function of the number of thin plates.

-0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8-40

-20

0

20

40

60

80

100

120

∆l/l

(µm

/m)

H (T)

Fe73

Al27

1 plate (40x5x1 mm)

5 plates (5 x 40x5x1 mm)


The magnetostriction is changing the sign from positive to negative when

the Al content increases.

0 5 10 15 20 25 30-30

-25

-20

-15

-10

-5

0

5

10

plate 12x6x0.5 mmH // with the long axis

∆l/l

(µm

/m)

Al content (at. %)


0.2 0.3 0.4 0.5 0.6 0.7 0.80

550

55

60

65

70

75

80

1 thin plate (40 * 5 * 1 mm) as-cast

5 thin plates glued together (40 * 5 * 1 mm) as-cast

Fe75

Al25

thin plates 1 thin plate (12 * 6 * 0.5 mm)

as-cast 1 thin plate (12 * 6 * 0.5 mm)

annealed @ 8000C/30' + 9000C/30' + 10000C/30' 1 thin plate (12 * 6 * 0.5mm)

annealed @ 9000C/120' + 10000C/120' + 11000C/120'

λ (p

pm)

Applied field (T)

Magnetostriction as a function of the thickness, number of thin plates measured at once and applied treatments.



-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

0

10

20

30

40

50

60

70

80

Fe1-x

Gax cast bars

10 x 3 x 3 mm3

(as-quenched state) x = 0.175 x = 0.195

H parallel with the long axis

∆l/l

(x 1

0-6)

H (T)

Very soft magnetic materials.

Low magnetic fields to achieve the saturation magnetostriction.

H parallel with the bars long axis (casting axis).



The value of λs increases gradually to 160÷180 ppm, depending on composition (the maximum value is smaller for

higher contents of Ga), when applying an external compressive stress of 3÷5 MPa. Over this compressive stress value, the strain remains constant.

Strain vs. force (stress)Strain vs. force (stress)

0 5 10 15 20 25 300

20

40

60

80

100

120

140

160

180

Hmax, //

= 0.8 T

Def

orm

atio

n (p

pm)

compressive stress (kg)

Fe82.5

Ga17.5

(10 x 3 x 3 mm3) as-cast thermally treated

(10000C for 72h; slow cooling to 8000C; rapid cooling to RT) thermally treated

(10000C for 72h; slow cooling to RT)

Paper DR-09, MMM Conference, Tampa, FL, 5-9 November 2007


� Fe100-xGax (x = 17; 20) and Fe100-xAlx (x = 20; 24) nanopowders prepared by arc-discharge method;� nanopowders embedded in Poxipol® commercial resin (resistance to water, outdoor conditions and many corrosive agents), CTM polymer, electrostrictive polymers and polyurethane;� different concentrations (10 ÷ 30 wt. %) of metallic nanopowders into the resin layer (t = 3 ÷ 5 mm);� magnetostriction of the composite layers measured by the electrical resistance strain gauge technique.

FeFe--GaGa and Feand Fe --Al composites Al composites –– Samples PreparationSamples Preparation


FeFe--GaGa and Feand Fe --Al composites Al composites -- NanopowdersNanopowders PreparationPreparation

Arc discharge (modified Kratschmer-Huffman carbon arc method)


26415476812.31.26σs (emu/g)

198359352440425323386Nanopowders average size (nm)*

Fe76Al24Fe80Al20Fe80Ga20Fe83Ga17Composition

FeFe--GaGa and Feand Fe --Al composites Al composites -- NanopowdersNanopowders characterizationcharacterization

* The size distribution of nanoparticles was determined by Dynamic Light Scattering (DLS) technique, using a MICROTRAC Nanotrac 252 Particle Size Analyser.


Ni nanoparticles size is ranging between 250 and 500 nm.

-0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8-70

-60

-50

-40

-30

-20

-10

0

10

20

30

40

∆l

/l (µ

m/m

)

H (T)

Ni77

R23

(wt. %) (Fe80Ga20)

28R

72 (wt. %)

(Fe80Al20)11

R89

(wt. %) (Fe76Al24)

10R

90 (wt. %)

FeFe--GaGa and Feand Fe --Al composites Al composites -- MagnetostrictionMagnetostriction

Nanopowders embedded in Poxipol® resin.


-0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8

-80

-70

-60

-50

-40

-30

-20

-10

0

10

∆l/l

(µm

/m)

H (T)

CTM + Fe80

Al20

(1.36%) CTM + Fe

80Al

20 (2.79%)

CTM + Fe80

Al20

(2.91%) polyurethane + Fe

80Al

20 (20%)

Nanopowders embedded in CTM and polyurethane

-0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8-12

-10

-8

-6

-4

-2

0

2

∆l/l

(µm

/m)

H (T)

CTM + Fe76

Al24

(?%)

FeFe--GaGa and Feand Fe --Al composites Al composites -- MagnetostrictionMagnetostriction


(Co,Ni)-Mn-(Ga,Al) system

- melt-spun ribbons (25 µm thickness)

- 3-D bulk shaped samples (12 x 6 x 0.5 mm)

- composites


SEM images taken on the cross-section of the Co38Ni33Al29 thin plate.

The images do not indicate any preferential direction of the grains.

Ag resin

Ribbons long axis

Electrons beam

Cross-section

Free surface

Cu-wheel contact surface

Al support

ribbon

SEM images taken on the cross-section of the Co38Ni33Al29melt-spun ribbons.

Samples morphologySamples morphology


-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

-5

0

5

10

15

20

25

30

35

40

45

50

55Plates (12x5x0.5 mm)H parallel

∆l/l

(ppm

)

H (T)

Ni50

Mn25

Ga25

Co50

Ni25

Ga25

Co38

Ni33

Al29

λλλλλλλλ--H and MH and M--H curves for H curves for NiMnGaNiMnGa , , CoNiGaCoNiGa and and CoNiAlCoNiAl thin platesthin plates

-0.75 -0.50 -0.25 0.00 0.25 0.50 0.75-50

-40

-30

-20

-10

0

10

20

30

40

50 H // with the long axis of the plates

Mag

netiz

atio

n (A

m2 /k

g)

H (T)

Ni50

Mn25

Ga25

Co50

Ni25

Ga25

Co38

Ni33

Al29


-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

-5

0

5

10

15

20

25

30

35

40

45

50

55Plates (12x5x0.5 mm)H parallel

∆λ/λ

(pp

m)

H (T)

Ni50

Mn25

Ga25

Co50

Ni25

Ga25

Co38

Ni33

Al29

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

-5

0

5

10

15

∆λ/λ

(pp

m)

H (T)

Ni50

Mn25

Ga25

H parallel H perpendicular

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0-5

0

5

10

15

∆λ/λ

(pp

m)

H (T)

Co38

Ni33

Al29


-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

0

10

20

30

40

50

∆λ/λ

(pp

m)

H (T)

Co50

Ni25

Ga25


λλλλλλλλ--H curves for H curves for NiMnGaNiMnGa , , CoNiGaCoNiGa and and CoNiAlCoNiAl thin platesthin plates


-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0-5

0

5

10

15

20

25

30

H parallel

∆λ/λ

(pp

m)

H (T)

Co38

Ni33

Al29

20 melt-spun ribbons glued together plate 12x5x0.5 mm

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0-25

0

25

50

75

100

125

150

175

200

225

Co38

Ni33

Al29

20 melt-spun ribbons

∆λ/λ

(pp

m)

H (T)

H parallel with the ribbons long axis H perpendicular on the ribbons long axis H perpendicular on the ribbons plane

Magnetostriction as a function of the sampleMagnetostriction as a function of the sample ’’s shape and s shape and direction of the applied fielddirection of the applied field


Despite the fact that λs is not comparable with Terfenol-D values, there are other important facts which can be considered for applications:

a. all samples are polycrystalline,

b. easy to prepare and reproducible (efficient and low cost),

c. not fragile and brittle,

d. the magnetoelastic properties can be further improved by tailoring the composition and treatment to be applied.

ConclusionsConclusions

Potential applications: in aeronautics and automotive industry

New 3-D Bulk Shaped Polycrystalline and Nanocomposite...

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