EFFECT OF COMPLEXING AGENTS ON nife NANOMATERIAL BY ELECTROCHEMICAL METHOD

For centuries, science has explored and continually redefined the frontiers of our knowledge. For a recently, we knew the concept of ever smaller scalenanoscale one billionth of a meter. Nanoparticles are particles with size measured in nanometers. According to International Organization for Standardization (ISO) Technical Specification 80004, a nanoparticle is defined as a nanoobject with all three external dimensions in the nanoscale, whose longest and shortest axes do not differ significantly, with a significant difference typically being a factor of at least 3. They have greater surface area per weight than larger particles, which causes them to be more reactive to some other molecules. Nanoparticles are used and being evaluated for use, in many fields as medicine, manufacturing, materials, environment, energy and electronics. In particular, magnetic nanoparticles are useful for a wide range of applications from data storage to medicines. If subjected to a magnetic field, the nanoparticles show a high magnetization that is very uniform throughout the material. The fact thatsoft magnetic nanoparticles can quickly switch magnetization direction once the external magnetic field is reversed makes them ideal for use in highfrequency electric circuits used, for example, in mobile phones. In particular, magnetic oxide nanomaterials, including iron oxide ( Fe3O4 and γFe2O3), spinel ferrites (MFe2O4 ; M = Mn, Zn, Cr, Ni, or Co) and hexagonal ferrite ( MFe12O19, M=Ba and Sr) are attracting much attention due to their wide application potentials in advanced magnets, electronic devices, information storage, magnetic resonance imaging (MRI), and drugdelivery technology. Thus, the synthesis and applications of nano structured magnetic ferrite has become a particularly important research field.20 Two approaches often represent manufacture of nanomaterials are “topdown” and “bottom–up”. “Topdown” refers to making nanoscale structures by machining, template and lithographic techniques, whereas “bottomup”, or molecular nanotechnology, applies to building organic and inorganic materials into defined structures, atombyatom or moleculebymolecule, often by selfassembly or self organization. In particularly, in the second approach, the nanoparticles are grown using electrodeposition from liquid solution or chemical vapor deposition (CVD). The synthesis from solution is more advantageous because it can produce large quantities of nanoparticles with relatively cost low and inexpensive infrastructure. While vapor growth is used mainly for semiconducting materials, the deposition from solution is employed for both metallic and semiconducting structures.7 The advanced physical properties of composite coatings quickly became clear and during the 1990s, new areas such as electrocatalysts and photoelectrocatalysts were considered. With the emergence of nanostructured materials over the last decade, electrodeposition techniques have provided a route to a variety of new nanomaterials. These include nano crystalline deposits, nanowires, nanotubes, nanomultilayers and nanocomposites. Strengthened composite coatings, enhanced electrical resistance in printed circuit boards, improved giant magnetoresistance in memory storage systems and increased microhardness for microdevices in microelectromechanical systems have been the focus of numerous studies 7. In this thesis, the work focused on effect of complexing agents on NiFe nanomaterial by Electrochemical method.

VIETNAM NATIONAL UNIVERSITY, HANOI

VNU UNIVERSITY OF SCIENCE

FACULTY OF PHYSICS

NGUYEN KHANH CHI

EFFECT OF COMPLEXING AGENTS ON

NiFe NANOMATERIAL BY ELECTROCHEMICAL METHOD

Submitted in partial fulfillment of the requirements for the degree of Bachelor of Science in Physics

(International Standard Program)

HaNoi - 2019

VIETNAM NATIONAL UNIVERSITY, HANOI

VNU UNIVERSITY OF SCIENCE

FACULTY OF PHYSICS

NGUYEN KHANH CHI

EFFECT OF COMPLEXING AGENTS

ON NiFe NANOMATERIAL

BY ELECTROCHEMICAL METHOD

Submitted in partial fulfillment of the requirements for the degree of Bachelor of Science in Physics

(International Standard Program)

Supervisor: Assoc Prof Dr Le Tuan Tu

HaNoi - 2019

I would also like to thank my friends for their advices, sharing, help andfriendship not only in my study but also in my life.

I would like to express my profound and heartfelt thanks to my family I amwhere I am today because of having family’s support in the past time

Finally, I would like to thank my family for unwavering support andencouraging me to keep up at work

Nguyễn Khánh Chi

LIST OF NOTATIONS ABBREVIATIONS

VSM A vibrating sample magnetometer/magnetometry

EDS Energy Dispersive X-ray Spectroscopy

CMS Center of Material Science

LIST OF FIGURES

CONTENTS

For centuries, science has explored and continually redefined the frontiers ofour knowledge For a recently, we knew the concept of ever smaller scalenanoscale-one billionth of a meter Nanoparticles are particles with size measured innanometers According to International Organization for Standardization (ISO)Technical Specification 80004, a nanoparticle is defined as a nano-object with allthree external dimensions in the nanoscale, whose longest and shortest axes do notdiffer significantly, with a significant difference typically being a factor of at least 3.They have greater surface area per weight than larger particles, which causes them

to be more reactive to some other molecules Nanoparticles are used and beingevaluated for use, in many fields as medicine, manufacturing, materials,environment, energy and electronics

In particular, magnetic nanoparticles are useful for a wide range ofapplications from data storage to medicines If subjected to a magnetic field, thenanoparticles show a high magnetization that is very uniform throughout thematerial The fact thatsoft magnetic nanoparticles can quickly switch magnetizationdirection once the external magnetic field is reversed makes them ideal for use inhigh-frequency electric circuits used, for example, in mobile phones In particular,magnetic oxide nanomaterials, including iron oxide ( Fe3O4 and γ-Fe2O3), spinelferrites (MFe2O4 ; M = Mn, Zn, Cr, Ni, or Co) and hexagonal ferrite ( MFe12O19,M=Ba and Sr) are attracting much attention due to their wide application potentials

in advanced magnets, electronic devices, information storage, magnetic resonanceimaging (MRI), and drug-delivery technology Thus, the synthesis and applications

of nano structured magnetic ferrite has become a particularly important researchfield.[20]

Two approaches often represent manufacture of nanomaterials are down” and “bottom–up” “Top-down” refers to making nanoscale structures bymachining, template and lithographic techniques, whereas “bottom-up”, or

“top-molecular nanotechnology, applies to building organic and inorganic materials intodefined structures, atom-by-atom or molecule-by-molecule, often by self-assembly

or self- organization In particularly, in the second approach, the nanoparticles aregrown using electrodeposition from liquid solution or chemical vapor deposition(CVD) The synthesis from solution is more advantageous because it can producelarge quantities of nanoparticles with relatively cost low and inexpensiveinfrastructure While vapor growth is used mainly for semiconducting materials,the deposition from solution is employed for both metallic and semiconductingstructures.[7]

The advanced physical properties of composite coatings quickly becameclear and during the 1990s, new areas such as electrocatalysts andphotoelectrocatalysts were considered With the emergence of nanostructuredmaterials over the last decade, electrodeposition techniques have provided a route to

a variety of new nanomaterials These include nano crystalline deposits, nanowires,nanotubes, nanomultilayers and nanocomposites Strengthened composite coatings,enhanced electrical resistance in printed circuit boards, improved giantmagnetoresistance in memory storage systems and increased microhardness formicrodevices in micro-electro-mechanical systems have been the focus of numerousstudies [7]

In this thesis, the work focused on effect of complexing agents on NiFe nanomaterial by Electrochemical method

1 CHAPTER 1: MAGNETIC NANOPARTICLES

In this chapter, the basics of nanomagnetics will first be presented followed

by a review on the synthesis and functionalization of magnetic nanoparticles

1.1 Classification of Magnetic Nanoparticles

A classification of nanostructured magnetic morphologies was desirablebecause of the correlation between nanostructure and magnetic properties Amongmany schemes proposed by various researchers, we have chosen here the followingclassification, which was designed to emphasize the magnetic behavior-relatedphysical mechanisms

Figure 1.1 Schematic presentation of different types of magnetic nanostructured

materials ( Leslie-Pelecky and Rieke 1996 ).

The classification is illustrated in Figure 1.1 [18] Type A is denoted forsystems consisting isolated particles with nanoscale diameters Since theinterparticle interactions can be ignored for these systems, their unique magneticproperties are completely attributable to the isolated components with theirreduced sizes Another type, type D, is assigned to bulk materials withnanoscale structure This type is featured by a significant fraction ( up to 50 % )

of the sample volume composed of grain bound-aries and interfaces Compared

with type A systems, the interparticle interactions cannot be ignored and the bulkmagnetic properties for type D are indeed dominated by the interactions It isbelieved that the length scale of the interactions can span up to many grains and iscritically related to the interphase characteristics Because of the existence of theinteractions and grain boundaries, the magnetic behaviors of type D nanostructurescannot be predicted theoretically simply by considering only the polycrystallinematerials with reduced length scales Other than type A and type D, intermediateforms such as core– shell nanoparticles (type B) and nanoparticle-basednanocomposites (type C) are classified, as shown in Figure 1.1 In type B, the shells

on magnetic nanoparticles, which may not be magnetic themselves, are usually used

to reduce interparticle interactions For type C systems, the magnetic properties ofnano composites are determined by the faction of magnetic nanoparticles as well asthe characteristics of the matrix material [18]

1.2 Single-domain particles

Single-domainand multidomain are important for ultrafine magnetic particles Domain walls have a characteristic width and energy associated withtheir formation and existence They separate domains – groups of spins all pointing

in the same direction and acting cooperatively Reversing magnetization isprimarily achieved by the motion of domain walls Figure 1.2 illustrates thedependence of coercivity on particle size by an experimental investigation.Multidomain is the case for large particles in which domain walls form energy-favorably As the particle size decreases below a critical diameter Dc, single-domainparticles form where the formation of domain walls becomes energeticallyunfavorable Thus, magnetization reversal cannot be obtained readily leading tolarger coercivities because of the lack of nucleation and motion of the domainwalls If the particle size continues to decrease, the spins are increasinglyinfluenced by thermal fluctuations and this phenomenon is calledsuperparamagnetism The estimated single-domain diameter for some materials inthe shape of spherical particles is listed [7]

Figure 1.2 Qualitative illustration of the coercivity behavior in the function of

particle sizes in particle systems Adapted from Leslie-Pelecky, D.L and Rieke, R.D (1996) Magnetic Properties of Nanostructured Materials, Chemistry of Materials,

8(8), 1770 – 83.

Table 1 Estimated values of single-domain sizes forspherical nanoparticles

without shape anisotropy Reproduced by permission of American Chemical

Society Adapted from Leslie-Pelecky, D.L and Rieke

Material Dcrit (nm) Material Dcrit (nm)

Hc approaches zero This superparamagnetism has two experimental criteria

which are no hysteresis for the magnetization curve and overlapping of themagnetization curves at different temperatures Possible reasons for imperfectsuperposition could be anisotropy effects, a wide distribution of particle sizes,

and changes of spontaneous particle magnetization with temperatures The widthand mean particle size of superparamagnetic particles can be obtained bydetermining the magnetization as a function of field It is necessary to point out thatthis method can only be used for weakly interacting systems where the interparticle interactions are not considered [18].

1.4 Size dependence of the magnetic properties of nanoparticles

Some studies found that the size-dependent effect of saturationmagnetization is attributable to the decrease of cohesive energy [7,14] Generally,the size-dependent cohesive energy En of spherical nanoparticles can be describedas

(1.1)where Svib denotes the vibrational part of the overall melting entropy Sm, R is theidealgas constant, and h denotes the atomic diameter By incorporating the bondorder-length-strength (BOLS) correlation mechanism into the Ising convention andthe Brillouin function, a simplified model can be developed to describe therelationship between the saturation magnetization MSn of spherical nanoparticlesand the average size D of nanoparticles:

(1.2)With increasing particle sizes, the magnetization of the samples increaseswith applied field The Ms ,Mr , and Hc of spherical Ni nanoparticles are size-dependent More specifically, the Ms and Mr increase and the Hc decreasesmonotonously with increasing D, indicating a distinct size effect According to theeffect of particle size on the magnetic coercivity, the Hc of the multidomainferromagnetic nanoparticles conforms to the rule as shown in the followingequation:

(1.3)

By means of thermal decomposition, He et al prepared single-phase

spherical Ni nanoparticles (23 to 114 nm in diameter) that are face-centered cubic

in structure Their measurement of magnetic hysteresis loop reveals that the

saturation magnetization MS and remanent magnetization increase and thecoercivity decreases monotonously with increasing particle size, indicating adistinct size effect They also found that with increase of surface-to-volume ratio of

Ni nanoparticles due to decrease of particle size, there is increase of the percentage

of magnetically inactive layer [14]

1.5 Introduction of soft magnetic materials

Soft magnetic materials are those materials that are easily magnetized anddemagnetized They typically have intrinsic coercivity less than 1000 Am-1 Theyare used primarily to enhance and/or channel the flux produced by an electriccurrent The main parameter, often used as a figure of merit for soft magneticmaterials, is the relative permeability (Mr, where Mr= B/MoH), which is measure ofhow readily the material responds to the applied magnetic field

Magnetically soft materials with high performances at high frequencies areone of the key materials for the recent development of high density electroniccircuits and increase of operation frequencies up to a few GHz They are useful asmagnetic cores in downsized inductors and DC–DC converters, and also aselectromagnetic noise absorbers to avoid malfunction of electronic circuits All ofthese applications have been calling for magnetically soft materials with highsaturation magnetization (Ms), high permeability and, in many cases, low energyloss [14]

For biomedical uses, the application of particles that presentsuperparamagnetic behavior at room temperature is preferred Furthermore,applications intherapy and biology and medical diagnosis require the magneticparticles to be stablein water at pH 7 and in a physiological environment Thecolloidal stability of this fluid will depend on the charge and surface chemistry,which give rise to both stericand coulombic repulsions and also depend on thedimensions of the particles, which should be sufficiently small so that precipitationdue to gravitation forces can be avoided Additional restrictions to the possibleparticles could be used for biomedical applications (in vivo orin vitro applications)

Forin vivo applications, the magnetic nanoparticles must be encapsulated with abiocompatible polymerduring or after the preparation process to prevent changesfrom the original structure, the formation of large aggregates, and biodegradationwhen exposed to thebiological system The nanoparticle coated with polymer willalso allow binding ofdrugs by entrapment on the particles, adsorption, or covalentattachment The major factors, which determine toxicity and the biocompatibility ofthese materials, are the nature of the magnetically responsive components, suchasmagnetite, iron, nickel, and cobalt, and the final size of the particles, their core,andthe coatings Iron oxide nanoparticles such as magnetite (Fe3O4) or its oxidizedformmaghemite (γ-Fe2O3) are by far the most commonly employed nanoparticlesforbiomedical applications Highly magnetic materials such as cobalt and nickelaresusceptible to oxidation and are toxic; hence, they are of little interest Moreover,the major advantage of using particles of sizes smaller than 100 nm is their highereffective surface areas, lower sedimentation rates, and improved tissular diffusion.Another advantage of using nanoparticles is that the magnetic dipole-dipoleinteractions are significantly reduced because they scale as r6 (r is the particleradius) [14] Therefore, forin vivo biomedical applications, magnetic nanoparticlesmust be madeof a non-toxic and non-immunogenic material, with particle sizessmall enough toremain in the circulation after injection and to pass through thecapillary systems oforgans and tissues, avoiding vessel embolism They must alsohave a high magnetization so that their movement in the blood can be controlledwith a magneticfield and so that they can be immobilized close to the targetedpathologic tissue Forin vitro applications, composites consisting ofsuperparamagnetic nano crystals dispersed in submicron diamagnetic particles withone sedimentationtimes in the absence of a magnetic field can be used because thesize restrictions arenot so severe as inin vivo applications The major advantage ofsing diamagnetic matrixes is that the superparamagnetic composites can be easilyprepared with functionality [14].

1.6 Introduction of NiFe magnetic materials

Ni-Fe alloys exhibit good soft magnetic properties such as low coercivity andhigh permeability and have been applied in a range of electric devices for thepurpose of shielding and converging magnetic flux Both the magneto crystallineanisotropy and magnetostriction constants become nearly zero at an alloycomposition of Fe22Ni78 and thus, this alloy is well-known for its excellent softmagnetic properties [12]

Permalloy is a nickel–iron magnetic alloy, which are extremely versatile andare used over a wide range of compositions, from 30 to 80 % Ni Over thiscomposition range the properties vary and the optimum composition must beselected for a particular application The high Ni content alloys have highpermeability; around 50 % Ni has high saturation magnetization and low Ni contenthave a high electrical resistance [14]

Permalloy (79 % Ni and 21 % Fe) are intensively used in MEMS devices,such as μ-relays, μ-switches, μ-pumps and μ-motors In electromagnetic devices ,the attainable energy density is limited by the saturation flux density (Bs) of the softmagnetic material used [14]

NiFe nano-material exists in various forms such as: thin film, nanowire,nanotube and nanoparticle, which can be synthesized by a number of physical orchemical methods, one of them is electrodeposition method that is low-cost andeffective There are several types of electrodeposition method as shown in Table 2

Table 2.Types of nanostructured materials which may be produced by

layers

Nanotubes/

nanowires

Nanocrytalline materials

Direct current

(DC)

For many advantage properties, a large number of studies have been carried

out on electrodeposited NiFe materials Liang et al has found that FeNi thin film

deposited with Mo or Al yields magnetically soft materials and that depositing with

B further increases the softness.The out-of-plane magnetic anisotropy of FeNi thinfilms is reduced by depositing with Al and completely removed by depositing with

B The effect of depositing with Mo isdependent on the Mo concentration Thecoercivity of FeNiMo and FeNiAl is reduced toless than a half of that of FeNi, and

a value as low as 40 A/m is obtained for FeNiB [14]

Shimada et al proposed a high permeability material composed of

micron-size Fe particles and nanometer-micron-size particles with magnetic softness The optimumvolume density of ferromagnetic NPs is an important factor to improve permeability

of the composites and their main study was on this subject However, the optimumconditions of many other factors such as NP size and its distribution, dispersion of

the NPs in Fe particle matrix and organic solvents, etc are yet unknown.Qin et

al.fabricated Ni80Fe20 NPs with various monodispersed sizes prepared by a polyolmethod to investigate their basic properties with magnetic softness [3]

Therefore, to evaluate and compare the results of these studies, this workconcentrated on investigation soft magnetic properties of NiFe nanoparticles

1.7 Magnetism of Magnetic Nanorods

Due to their quasi one-dimensional structure, magnetic nanorods exhibitunique magnetic properties The magnetic properties of a nanorods are related tomany parameters of the nanorods, such as composition, length and diameter For a

multi-segment nanorods, its magnetic properties are also related to the layerthickness and the spacing between layers Besides, the low dimensionality ofnanorods brings about fundamental magnetic anisotropy Some magnetic properties

of magnetic nanorods, such as coercivity, remanence, saturation magnetic field andsaturate magnetization, are dependent on the direction of the externally appliedmagnetic field The giant magnetoresistance of a multilayer nanorods is caused bythe segmented structure of the nanorods [14]

1.8 Shape Anisotropy

When a magnetic field is applied to a spherical object, the orientation of themagnetic field does not affect the magnetization of the spherical object However,the magnetization of a non-spherical object depends on the orientation of themagnetic field It is easier to magnetize a non-sphericalobject when the magneticfield is applied along the long axis of the object than along its short axis For anobject under an external magnetic field, the magnetic field inside the object isusually called the demagnetizing field, as this field tends to demagnetize the

material The demagnetizing field, Hd, is proportional to the magnetization M that

creates it, but in an opposite direction, as given by:

Hd = −NdM (2.1)

where the demagnetizing factor Nd is related to the shape of the object Because thecalculation is quite complicated, the exact value Nd can be calculated only for anellipsoidal object with uniform magnetization all over the object To an ellipsoidalobject with semi-axes a, b and c (c ≥ b ≥ a), the sum of demagnetization factorsalong the three semi-axes ( Na, Nb and Nc) equals to 4π

Na+ Nb+ Nc= 4π (2.2) For a given magnetization direction, the magnetostatic energy ED (erg/cm3) isgiven by:

ED = Nd Ms2 (2.3) where Ms (emu/cm3) is the saturate magnetization of the object, and Nd is thedemagnetization factor for the magnetization direction [14]

The magnetization hysteresis loop of a sample illustrates how this sampleresponds to an external magnetic field, and theoretically, the magnetizationhysteresis loop of an arbitrary sample can be obtained by minimizing the total freeenergy of the object in an external magnetic field The hysteresis loop of an object isaffected by many factors, such as material, microstructure, shape, size of the object,the orientation of the magnetizing field, and the magnetization history of thesample Figure 1.3 schematically shows two typical magnetization hysteresis loopsfor an array of Ni nanorods

Figure 1.3: Hysteresis loops for a nickel nanorods array The diameter of

the nanorods is 100 nm, and their length is 1 µm (a) The applied magnetic field H

is parallel to the axis of the nanorods; (b) the applied field H is perpendicular to the axis of the nanorods.

The parameters are often used in describing the characteristics of a sampleinclude the saturate magnetization Ms, the remanent magnetization Mr, thesaturation field Hsat and the coercivity Hc As shown in Figure 1.3, the saturationfield Hsat is the field required for the sample to achieve the saturate magnetization

Ms; the remanent magnetization Mr is the magnetization of the sample when theexternal magnetic field is moved away; the coercivity Hc is the magnetic fieldcorresponding to the zero magnetization There is another important parameter,switching field Hs, which is often used in analyzing magnetic nanomaterial It isdefined as the field at which the slope of the M–H loop reaches its maximum value.Actually, it is the field required to switch the magnetization from one direction tothe opposite direction Usually, the switching field Hs is equal to the coercivity Hc

The saturate magnetization Ms of an object is achieved when all the magneticmoments in the object are aligned in the same direction Therefore, the saturate

magnetization Ms is an intrinsic property of a magnetic material, which is notrelated to thesize and shape of the sample

The magnetic behaviors of a nanorods array are mainly determined by twoparameters including magnetic properties of the individual nanorods, andinteractions among the individual magnetic nanorods, which are related to thegeometry parameters of the nanorods array [14]

2 CHAPTER 2: EXPERIMENT METHODS

2.1 Electrodeposition

There are several techniques such as VLS (Vapor Liquid Solid method),CVD (Chemical Vapor Deposition) and template assisted synthesis are developedfor the synthesis of nanowires [19, 14] Among them template assistedelectrochemical synthesis is facile, cost effective, as it can be used for producinglarge quantities of nanorods with desired features like aspect ratio, composition andsize [16] In addition, this method allows the fabrication of single-segment andmulti-segment nanorods Using this technique, different segments can be introducedalong the axis of a nanorods, and it is particularly attractive for the realization ofmulti-functionality Furthermore, the materials for individual segments may bemetals, alloys, metal oxides or electronically conducting polymers, and so specificmagnetic, optical or electrical properties can be achieved [11]

In 1996, Martin [6] first employed this technique in synthesizing metallicnanowires using polycarbonate membrane as template Subsequently, theelectrochemical deposition has been used extensively in fabricating single metallicnanorods and multilayered metallic nanorods (super-lattice) with controlledthickness for magnetic property studies [19, 7] Electrodeposition is a process inwhich an electrical current passes through an electrolyte of metallic ions, and areduction takes place when the ion encounters the cathode (working electrode) [2]

In the electrodeposition using a nanoporous membrane as a structure to createnanorods arrays, electrodeposition takes place in the channels of the membrane Asshown in figure 2.1, electrodeposition of nanowires is usually done in a three-electrode arrangement, consisting of a reference electrode, a specially designed

cathode and an anode or counter electrode Usually the applied substrate will beserved as the working electrode and several inert metals will be served as counterelectrode and reference electrode, such as Pt wire The standard Ag/AgCl is also theoften-used reference electrode

Initially, Anodized Alumina Membrane (AAM) and ion track-etched polymermembrane were developed for lab filtration applications These two types ofmembrane occupy relatively precise pore structure and narrow pore sizedistribution, which is suitable for filtrate certain sized material and biologicalparticles

Figure 2.1 Three-electrode arrangement for electrodeposition of nanorods

In comparison to nanorods electrochemically synthesized using commercialAAM as template, the nanorods fabricated electrochemically based on track-etchedpolycarbonate membranes have much better diameter uniformity, smooth surfaceand cheap The drawback is that the nanorods density is low (membrane poredensity around 109 / ) and the distribution is not uniform, which could affect thesubsequent magnetic property measurements due to the different interactions amongvicinal individual nanorods [1]

2.2 Sonoelectrodeposition system

There are many ways to create NiFe-nanostructured materials includingphysical techniques such as mechanical deformation, arcmelting, vacuumevaporation (sputtering and thermal evaporation), laser ablation pulse, chemical

methods, and physicochemical method such as electrodeposition Up to now, the

vacuum evaporation is the most used method Electrodeposition is a promising way

to obtain nanorods or thin film because it is less expensive than physical methods,less complicated than chemical methods But by this technique, it is difficult to getnanoparticles with large quantity Sonoelectrochemistry was developed to makenanoparticles It combined the advantages of sonochemistry and electrodeposition.Sonochemistry is a very useful synthetic method which was discovered as early as

1934 that the application of ultrasonic energy could increase the rate of electrolyticwater cleavage The effects of ultrasonic radiation on chemical reactions are due tothe very high temperatures and pressures, which develop in and around thecollapsing bubble Sonoelectrochemistry has the potential benefit of combiningsonochemistry with electrochemistry Some of these beneficial effects includeacceleration of mass transport, cleaning and degassing of the electrode surface, and

an increased reaction rate [14]

Figure 2.2 Controller system.

Figure 2.3 Sonoelectrode system.

The sonoelectrodeposition system has a controller system in Figure 2.2(PC,sonochemical-potentiostat controller), a sonotrode in Figure 2., a platinumsubstrate

The bath composition and fabricating conditions are given in Table 3

Table 3 Electrolyte composition and operating conditions