Application of soft magnetic of amorphous alloys

Nguyen Hoang VietNano-Particulate Materials Processing (NPMP)

Contents

IntroductionAmorphous structure characterizationsApplication

AlloysPreparationDevice

Summaries

Amorphous configuration exhibits unique properties such as high strength, large elastic limit, excellent wear & corrosion resistance…Terms: Amorphous Alloys, (Bulk) Metallic glasses, Inorganic Amorphous Materials,…Crystalline Structure Amorphous

Structure

Properties of Metallic GlassesProperties of Metallic Glasses

High strength & elasticity of BMGsHigh strength & elasticity of BMGs

Potential for structural applicationPotential for structural application

High strength of Ti- based BMGsHigh strength of Ti- based BMGs

~ 2200MPa~ 2200MPaAdapted from Adapted from http://www.nanonet.go.jp/english/mailmag/2004/014a.html

Characteristics of Metallic Glass

20 40 60 80 100

20h

10h

5h

2h

1h

Ti Cu Ni Sn NiTi

2

Inte

nsi

ty [

arb

itra

ry u

nit

s]

2 [degrees]

Diffraction pattern (TEM)

Complete amorphization after 20h of MA

Ti50Cu25Ni20Sn5 amorphous alloy by MA

Amorphous Structure Charactezations

650 700 750 800 850-3

-2

-1

0

1

2

Ti50

Cu25

Ni25

Sn5

J/g

747KTg=716K

Exo

therm

ic

Heat

flo

w [

mW

/mg

]

Temperature [K]

DSC analysis

Glass transition Temp.

Crystallization Temperature

After Oanh NH et. al. NPMP LAB[3].

Alloys[5]

Class of alloys[2]: containing about 80 atom % of the transition metals Fe, Co, and Ni, and about 20 atom % of metalloid elements sauch as B, C, P, Ge and Si.

Fe-based alloys: high saturation induction, low permeability and high magnetostriction. >> low frequency app.; big mass; low priceFe-Ni-based alloys: medium saturation induction and permeability. >> better high frequency app.Co-based alloys: relatively low saturation induction but excellent high-frequency & nearly zero magnetostriction. >> special app. (magnetic head, sensors, etc.), smaller mass, high price

Application

Preparation [5]

Form Method

PowderMechanical alloying, atomization*,

electrodeposition

RibbonPlanar flow (tape) casting* or melt

spinning

Wire Water-in quenching technique*

BulkMold casting, consolidation of amor.

powder and ribbon**.

*: *: rapid quenching methodrapid quenching method

**: sintering – SPS, hot press, hot extrusion,**: sintering – SPS, hot press, hot extrusion,……

Relationship between permeability, e (at 1 kHz) and saturation polarization for soft magnetic materials (adapted from Ref.

[193][4]).

Isotropic magnetic Isotropic magnetic properties?properties?Stress – differences in cooling rates through thickness of ribbons => Anisotropy

Thermal annealing – removal of internal stresses => Mitigating the Anisotropy

Fig.: The Nd60Fe10Co20Al10 alloys prepared by splat quenching,

melt spinning, and mold casting.

Primary crystallization of amorphous precursors => very fine nanocrystalline grain size in amorphous matrix

Designing and developing a nanocrystalline soft magnetic Designing and developing a nanocrystalline soft magnetic

material from an amorphous precursor routematerial from an amorphous precursor route[5-Michael E. McHenry[5-Michael E. McHenry et. al.et. al.]]

DevicesExcellent soft magnetic of magnetic glasses applied in various devices belong to these groups [4]:

Power electrical devices: transformer, MotorsInductive components used in electricsMagnetic headsMagnetic headsMagnetic shieldsSensors & transducers

Magnetic headsCo-based amor. materials: nearly zero magnetostriction, high density, high frequency and high reproducibility recording.Co-Zr-based thin film in heads for perpendicular magnetic recording.

Sensors [4]:

Magnetometers: using zero-magnetostrictive alloys. Co-base amor. alloyStress sensors: using high magnetostrictive alloys. Fe-base amor. alloy

SummariesThe progressThe progress in amor. magnetic materials is in amor. magnetic materials is characterized characterized by the further improvement of the materials and devicesby the further improvement of the materials and devices rather than by the appearance of new alloys and new fields rather than by the appearance of new alloys and new fields of application. Several devices are commercially available, of application. Several devices are commercially available, e.g., magnetic heads and shields, inductive components for e.g., magnetic heads and shields, inductive components for the electronics industry, ribbons for anti-thief security the electronics industry, ribbons for anti-thief security systems, etc. systems, etc.

Some types of sensorsSome types of sensors have already found have already found practical usepractical use. .

With regard to With regard to amorphous coresamorphous cores in in distribution and power distribution and power transformerstransformers their usage is strongly influenced not only by their usage is strongly influenced not only by the need to solve a number of technical problems but also the need to solve a number of technical problems but also by the improvement of traditional materials. by the improvement of traditional materials.

The The application of metallic glassesapplication of metallic glasses has not proceeded as has not proceeded as quickly as was thought earlier and as was to be expected quickly as was thought earlier and as was to be expected in view of the saving in energy.in view of the saving in energy.

References1.1. ““MAGNETIC PROPERTIES OF AMORPHOUS ALLOYS”, MAGNETIC PROPERTIES OF AMORPHOUS ALLOYS”,

C. D. Graham, Jr. and T. Egami, Ann. Rev. Mater, C. D. Graham, Jr. and T. Egami, Ann. Rev. Mater, Sci. 1978. 8:423-57Sci. 1978. 8:423-57

2.2. ““Metallic Glasses”, Gary J. Shiflet, Ullmann's Metallic Glasses”, Gary J. Shiflet, Ullmann's Encyclopedia of Industrial Chemistry, Copyright © Encyclopedia of Industrial Chemistry, Copyright © 2007 by John Wiley & Sons, Inc.2007 by John Wiley & Sons, Inc.

3.3. Ph.D thesis, Oanh NH, 2006Ph.D thesis, Oanh NH, 20064.4. ““Amorphous and nanocrystalline materials for Amorphous and nanocrystalline materials for

applications as soft magnets”, Michael E. applications as soft magnets”, Michael E. McHenry*, Matthew A. Willard, David E. Laughlin, McHenry*, Matthew A. Willard, David E. Laughlin, Progress in Materials Science 44 (1999) 291-433Progress in Materials Science 44 (1999) 291-433

5.5. Recent progress in the Application of Soft Recent progress in the Application of Soft Magnetic Amorphous materials: Alloys, Magnetic Amorphous materials: Alloys, Preparation, Devices, G. Konczos et la., Physica Preparation, Devices, G. Konczos et la., Physica Scripta, Vol. 124, 42-48, 1988Scripta, Vol. 124, 42-48, 1988

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