bluuebunny/crossref_metadata_2025 huggingface dataset:
Smartflex NiTi Wires for Shape Memory Actuators
Authors: Fumagalli L. , Butera F. , Coda Alberto
Published: March 2009

Shape Memory Alloys (SMAs) are active metallic materials classified nowadays as
“smart” or “intelligent” materials. One of the main areas of interest is that of actuators.
The use of Shape Memory Alloys in actuators offers the opportunity to develop robust,
simple and lightweight elements that can represent an alternative to electro-magnetic
actuators commonly used in several fields of industrial applications, such as
automotive, appliances, etc. The obvious simplicity of mechanical design and minimum
number of moved parts is amazing for an actuator.
NiTi SMAs demonstrated to have the best combination of properties. Due to its
relatively high recovery stress and strain, actuators providing significant force and
stroke can be designed. There are perhaps thousands of applications of NiTi-based
actuators mentioned in literature and in patents. Successful applications will build on
SMA strengths whilst taking into account its weaknesses.
SAES Getters S.p.A., thanks to its vertically integrated process and to the scientific and
quality approach, developed a NiTi-based wires family which can represent a very good
solution for shape memory actuators.
The mechanically stabilized SAES Smartflex NiTi actuators show a very sophisticated
profile of properties. In this paper the mechanical, thermal and electrical response of
these shape memory wires, at diameters ranging from 25 to 500 mm, under different
working conditions, simulating the actual operating condition in real actuators, will be
examined in depth and discussed, in order to direct the design of the actuator so that
the functional properties of the material can be completely exploited. The thermomechanical
properties have been investigated and measured by several methods. The
most common and useful tests for these commercially available wires will be also
described.
Magnetic Properties and Microstructures of Rapidly Solidified FePd Alloy Ribbons
Authors: Kishi Yoichi , Yajima Zenjiro , Okazaki Teiko , Furuya Yasubumi , Wuttig Manfred
Published: March 2009

It is well known that FePd alloys are effective as a magneto-thermoelastic actuator material,
because they have large magnetostriction and shape memory effect. In order to use the alloys for a
micro-actuator, magnetic properties and microstructures have been examined as for rapidly solidified
Fe-29.6 at% Pd alloy ribbons. The ribbons exhibit a large magnetostriction at room temperature and
good shape memory effect. Magnetostriction and coercive force of the ribbons markedly depend on
the direction of the applied magnetic field. Maximum values of magnetostriction and coercive force
are obtained at θ = 85 degree (θ is the angle between the magnetic field and the ribbon plane). Relief
effects corresponding to the formation of FCT martensite variants are observed on the grains. X-ray
diffraction profile at room temperature shows that FCT martensitic phase and FCC parent phase
coexist in the ribbon. Dense striations are observed in the TEM bright field images of FCT martensite
plates. Selected area electron diffraction patterns revealed the striations to be thin twins.
Surfactant Modified Nickel-Manganese-Gallium Powder and Silicone Composites
Authors: Underhill Royale S. , Stevens Krystal A. , Fisher Gary C.
Published: March 2009

Power supplies are often the limiting factor for operation of many portable electronic
devices. Batteries contribute significantly to their weight and impose limitations on operational
longevity. Harvesting vibratory energy from the environment for conversion to electrical energy
has been proposed as a means to address these problems. Previously, DRDC Atlantic has shown
that single crystals of nickel-manganese-gallium (NiMnGa) can produce large reversible stressinduced
and magnetic field-induced strains of up to 10%. It has been proposed that NiMnGa
magnetic shape memory alloys may be an ideal alloy to harvest mechanical energy. The drawback
to monolithic NiMnGa crystals is that they are susceptible to intergranular fracture. To address this
issue, a composite of the alloy in a polymer matrix has been examined in the hopes of improving
toughness and formability. Good bonding between the polymer and the powder is needed to
facilitate optimum transfer of force between the two components. The objective of this study was
to understand and optimize the polymer-alloy interactions. The polymer matrix chosen was Dow
Corning Sylgard 186. It was determined that the Sylgard 186 prepolymer base interacts with the
oxidized surface of the NiMnGa particles. Silane coupling agents were also investigated to
examine their effect on the interfacial interactions. No change in properties were observed.
Shape Recovery and ε - γ Transformation in Fe29Mn7Si5Cr SMA
Authors: Van Caenegem Nele , Verbeken Kim , Petrov Roumen H. , van der Pers N.M. , Houbaert Yvan
Published: March 2009

The shape memory behaviour of a Fe29Mn7Si5Cr based alloy has been investigated.
Characterization of the martensitic transformation and the different structural constituents was
performed using optical microscopy, X-ray diffraction (XRD) methods and electron backscatter
diffraction (EBSD). The transformation temperatures and the shape recovery were determined by
dilatometry on prestrained samples.
Smart Sensing Uniforms for Emergency Operators
Authors: Paradiso Rita , Bourdon Lionel , Loriga Giannicola
Published: March 2009

Textile integration of smart sensor systems is the key technology for the success of future
e-garments oriented to emergency operators. Ubiquitous recording and transmission of human and
environmental data will allow combining comfort and protection leveraging with the existing smart
textile, microelectronics and telecommunication technologies. The challenge offered by emergency
situation is mainly in the difficulty to acquire data in a very aggressive environment, during hard
physical activity; conditions that will increase the risks of signals artefacts, as well as the presence
of positive and negative false events.
Security is addressed through the implementation of systems combining body sensing platform, for
health alertness and environment sensing platform for context awareness; the full system has also to
guarantee protective functionality. State of art textile technology allows the monitoring of heart and
respiratory rate, humidity rate, activity rate, GSR and EMG, while core and external temperature,
posture via accelerometers, absolute position via GPS are easily monitored through standard
sensors. The body sensing platform requires a direct contact with the operator skin leading to the
implementation of a sensing inner garment, at the same time environment platform are integrated in
a protective jacket that is also hosting the alarm systems and the electronic unit for signal
processing and transmission hardware.
This paper is reporting about a study done with a pioneer e-textile system named Wealthy on
healthy subjects during extreme conditions.
Wealthy platform is currently evolving in a new one, specially designed for emergency scenarios,
developed in the frame of the project Proetex, a preliminary description of the new system is
presented; the new system that is under first testing phase, has been designed to be used without
interfering with operator activities.
Properties and Applications of Dry-Spun Carbon Nanotube Yarns
Authors: Atkinson Ken R. , Skourtis Chris , Hutton S.R.
Published: March 2009

Carbon nanotubes (CNTs) are of great technical interest because of their high strength
(~37 GPa), good electrical conductivity, excellent thermal conductivity (3 000 W m-1K-1), and good
thermal stability at both low and high temperatures. A difficulty has been absence of reliable
methods of controlling assembly of the large numbers of CNTs required for practical applications.
We have developed, in collaboration with our partners at the NanoTech Institute, University of
Texas at Dallas, a solid-state process for spinning CNTs into yarns without the use of binders that
usually degrade the electrical and thermal conductivities. The singles yarns were twisted together to
give coarser (multi-stranded) stronger yarns that were knitted using a miniature 5-needle machine.
Mechanical and electrical properties of the yarns and knitted tubes were assessed simultaneously
using specially developed test equipment. Some specific applications under investigation include
using the CNT yarns as incandescent and x-ray filaments, as electrodes for biomedical applications,
and as composites with high toughness. Tests show the biocompatibility of the CNT yarns for
selected cell lines is high.
Photo-Catalysis of Red Wine Stains Using Titanium Dioxide Sol-Gel Coatings on Wool Fabrics
Authors: Hurren C.J. , Liu R.T. , Liu Xin , Wang X.G.
Published: March 2009

This paper investigated the use of titanium dioxide sol-gel coatings to photo-catalyse red
wine stains on wool fabrics. Coatings were produced by the hydrolysis and condensation of
titanium butoxide (Ti(OC4H9)4) on the surface of wool fabrics after pad application. Coatings were
partially converted to the anatase form of titanium dioxide by prolonged immersion in boiling
water. The coating presence was confirmed using scanning electron microscopy, UVspectrophotometry
and atomic force microscopy. Coated samples were measured for photo-catalytic
activity by degrading red wine stains from the surface of the coated fabric. The level of photocatalysis
was determined for each of the coating systems after 168 hours. Red wine stains were
photo-catalysed and level of staining was reduced from the UV exposed surface of the coated wool
fabric.
Functional Properties of Electroless Silver-Plated Cotton Fabric via LTP Pre-Treatment
Authors: Jiang Shou Xiang , Tao Xiao Ming , Yuen C.W.M. , Kan C.W. , Zhang L. , Choi P.S.R.
Published: March 2009

Silver-plated textiles have exhibited their specific features not only on mechanical
performance but also on functional properties. In this study, silver plating technique was applied
on cotton fabric to improve its functional properties, especially the anti-bacterial and anti-UV
properties. Silver plating was conducted in this research with the aid of oxygen and argon
low-temperature plasma (LTP) pre-treatment on the cotton fabric to manipulate the film of the
coating. The silver-plated cotton fabric was characterized in terms of its functional properties.
The micro-roughness formed on the cotton fabric after the LTP pre-treatment facilitated the silver
particles deposition. As a result, the anti-bacterial and anti-UV properties of the silver-plated
cotton fabric and the water repellent ability of the cotton fabric were improved after the
silver-plating process.
Lotus-Effect®: Biomimetic Super-Hydrophobic Surfaces and their Application
Authors: Spaeth Manuel , Barthlott Wilhelm
Published: March 2009

The majority of organismic surfaces, like the plant cuticle, is not smooth but micro-structured.
Moreover, they are often covered with hydrophobic wax crystals, some hundred nm in size. The
combination of micro- and nanostructures, together with a hydrophobic chemistry, generates the
phenomenon of super-hydrophobicity: Water-droplets on such surfaces exhibit contact angles above
140°. Furthermore, dirt particles can barely adhere and are removed by running water only, hence
they are called ‘self-cleaning’.
The underlying physico-chemical principles were successfully applied to technical prototypes. This
technical conversion was patented and the trade mark Lotus-Effect® was introduced in the mid
1990s. Since then several Lotus-Effect® products like a façade paint, a glass coating or a spray were
introduced. Another area of application for which prototypes exist, are textiles for awnings, tents or
other outdoor purposes.
Recently a different aspect of such surfaces is investigated: structures retaining air under water.
Several floating plants and semiaquatic animals show this ability. The aim of this project is to
develop technical surfaces for long time application in ships and pipelines, as an air film between
surface and liquid leads to drag reduction and thus savings of energy.
Accomplishing of Convergent Systems for Mobile Personalized Information Monitoring
Authors: Carpus Eftalea , Dorogan Angela , Visileanu Emilia , Ignat Mircea , Onose Gelu , Nanu Dimitrie , Carpus Ioana , Buzdugan Maria , Radu Marcela
Published: March 2009

There is a critical need of integrating the basic electronics technologies, sensors,
computers and communications into textiles, so that these, until now passive, to be able to be
changed into interactive, intelligent information infrastructure in order to facilitate the personalized
mobile information processing to the end user. A field with a special application potential of the
intelligent textiles is the medical field. The paper will present a knitted textile product having an
attached resistive sensor meant for monitoring the foetus heart rate during the intrauterine
development period.
EAP Actuators for Biomimetic Technologies with Humanlike Robots as one of the Ultimate Challenges
Authors: Bar-Cohen Yoseph
Published: March 2009

Since the Stone Age, people have tried to reproduce the human appearance, functions,
and intelligence using art and technology. Any aspect that represents our physical and intellectual
being has been a subject of copying, mimicking and inspiration. Recent surges in technology
advances led to the emergence of increasingly more realistic humanlike robots and simulations.
Making such robots is part of the field of biologically inspired technologies - also known as
biomimetics - and it involves developing engineered systems that exhibit the appearance and
behavior of biological systems. Robots with selectable characteristics and personality that are
customized to our needs and with self-learning capability may become our household appliance or
even companion and they may be used to perform hard to do and complex tasks. In enabling this
technology such elements as artificial intelligence, muscles, vision, skin and others are increasingly
improved. In this paper, making humanlike robots will be described with focus on the use of
artificial muscles as the enabling technology and the related challenges.
Conducting Polymer Soft Actuators Based on Polypyrrole -Training Effect and Fatigue
Authors: Kaneto Keiichi , Suematsu Hirotaka , Yamato Kentaro
Published: March 2009

Work behaviours and training effects of artificial muscle based on
electrochemomechanical strain (ECMS) of conducting polymer, polypyrrole (PPy) films have
been studied under tensile stress up to 5 MPa. PPy films were electrochemically deposited in
dodecylbenzene sulfonic acid. Cyclic voltammetry and ECMS were measured in 1M NaCl
aqueous solutions. At higher stress, a larger creeping due to the conformation change, slipping
and/or breaking of polymer chains was observed. After the experience of large tensile stress an
appreciable increase of strain (training effect) was observed, when the film was actuated at lower
tensile stress. The training effect was discussed in terms of the relaxation of anisotropic strain
induced during the creeping. The conversion efficiency from electrical to mechanical energies was
0.07 % at 3 - 4 MPa being the maximum. Degradation of film was found to be accelerated under
higher tensile stress from the measurement of conductivity.
Optimization of IPMC Actuator Conversion Efficiency
Authors: Brunetto Paola , Fortuna Luigi , Giannone Pietro , Graziani Salvatore , Strazzeri Salvatore
Published: March 2009

IPMCs are suitable candidates to realize artificial muscles for possible autonomous applications. In
such a field power budget is of great importance. The goal of this paper is to maximize the IPMC
electromechanical conversion efficiency in order to increase the performance of these transducers.
More specifically, the optimal frequency, amplitude, and waveform to be used to drive the IPMC
membrane has been investigated. By using a novel model of IPMC actuators, the waveform of the
applied voltage signal that maximize the IPMC conversion efficiency was found. The amplitude of
the first 15 harmonics of the IPMC driving signal was determined, for different constrains such as
the minimum output power and the maximum input voltage.
The paper reports about the proposed IPMC model, the optimization algorithm, the optimal driving
signals, and the validation of the approach.
Metal Ion Implanted Compliant Electrodes in Dielectric Electroactive Polymer (EAP) Membranes
Authors: Dubois Philippe , Rosset Samuel , Niklaus Muhamed , Dadras Massoud , Shea Herbert
Published: March 2009

One of the key factors to obtain large displacements and high efficiency with dielectric
electroactive polymer (DEAPs) actuators is to have compliant electrodes. Attempts to scale DEAPs
down to the mm or micrometer range have encountered major difficulties, mostly due to the
challenge of micropatterning sufficiently compliant electrodes. Simply evaporating or sputtering
thin metallic films on elastomer membranes produces DEAPs whose stiffness is dominated by the
metallic film.
Low energy metal ion implantation for fabricating compliant electrodes in DEAPs presents several
advantages: a) it is clean to work with, b) it does not add thick passive layers, and c) it can be easily
patterned. We use this technology to fabricate DEAPs micro-actuators whose relative displacement
is the same as for macro-scale DEAPs. With transmission electron microscope (TEM) we observed
the formation of metallic clusters within the elastomer (PDMS) matrix, forming a nano-composite.
We focus our studies on relating the properties of this nano-composite to the implantation
parameters. We identified the optimal implantation parameters for which an implanted electrode
presents an exceptional combination of high electrical conductivity and low compliance.
Bio-Inspired Distributed Electroactive Polymer Actuators for Possible Space Applications: Concept Design
Authors: Carpi Federico , Menon Carlo , De Rossi Danilo
Published: March 2009

Technologies for space applications are often considered to be rather conservative, aimed
at ensuring reliability and robustness. Nevertheless, novel concepts coming from research activities
have been and are always the lymph for the development of successful and competitive new
solutions. This paper presents new concepts and ideas inspired by natural systems with distributed
actuation embedded in their structure, considered as ideal models for possible uses in space
applications. Preliminary concepts for possible technical solutions for long-term future
implementations are here proposed and briefly analyzed. Peristaltic-like actuations obtained by the
use of dielectric elastomer actuators is proposed as one of the most promising solutions.
Experimental performances of a single actuation unit are here presented and directions for future
implementations are proposed.
Rate Limits in Conducting Polymers
Authors: Shoa Tina , Madden John D. , Fok Chi Wah Eddie , Mirfakhrai Tissaphern
Published: March 2009

Conducting polymer actuators are of interest in applications where low voltage and high
work density are beneficial. These actuators are not particularly fast however, with time constants
normally being greater than 1 second. Strain in these actuators is proportional to charge, with the
rate of charging being found to limit the speed of actuation. This rate of charging is in turn limited
by a number of factors, the dominant factor depending on the actuator and cell geometry, the
potential range, the composition and the timescale of interest. Mechanisms that slow response can
be as simple as the RC charging time arising from the actuator capacitance and the series resistances
of the electrolyte and the contacts, or may involve polymer electronic or ionic conductivities, which
can in turn be functions of potential. Diffusion can also be a factor. An approach is presented to
help estimate the relative magnitudes of these rate limiting factors, thereby enabling actuator
designs to evaluated and optimized for a given application. The general approach discussed is also
useful for analyzing rate limits in carbon nanotube actuators and other related technologies.
New Composites Based on Liquid Crystalline Elastomers and Electroactive Nanomaterials
Authors: Domenici Valentina , Župančič Blaž , Remškar Maja , Laguta Valentin V. , Veracini Carlo Alberto , Zalar Boštjan
Published: March 2009

The insertion of inorganic nanoparticles and nanowires in a liquid crystalline elastomeric
environment is here investigated. The combination of ferroelectric and conductive properties of the
nanomaterials with the thermo-mechanical and shape memory response of liquid single crystal
elastomers based on polysiloxane is indeed very promising for new technological applications, such
as electroactive actuators. In this work the preparation and physical-chemical properties of new
composites are presented and discussed in comparison with those of standard liquid single crystal
elastomers (LSCEs). In particular, we are reporting the preliminary results of new composites
including either lead titanate nanoparticles or molibdene oxide nanowires, having different electric
and conductive properties.
Tough Hydrogel - Learn from Nature
Authors: Furukawa Hidemitsu , Gong Jian Ping
Published: March 2009

Gel is a fascinating material for its unique properties, such as phase-transition,
chemomechanical behavior, stimuli-responsiveness, low surface sliding friction, and for its possible
wide application in many industry fields. Recently, hydrogels have drawn special attraction in
biological field due to its possible applications as soft man-made tissues. However, conventional
hydrogels, especially polyelectrolyte gels, are mechanically too weak to be practically used in any
stress or strain bearing applications. Inspired by the structure of articular cartilage, we discovered a
general method to obtain very strong polyelectrolyte hydrogels containing 60-90% water by
inducing a double-network (DN) structure for various combinations of hydrophilic polymers. The
soft and wet gel materials with both a high strength and an extremely low surface friction would
find wide applications not only in industry but also in biomedical field, for example, as substitutes
of articular cartilage or other bio-tissues.
Sprayed Sensor Using IPMC PAINT
Authors: Park Il Seok , Tiwari Rashi , Kim Kwang Jin
Published: March 2009

In this study, we are testing a sensing response of recently developed IPMC fabrication
method, “IPMC Paint”, which can be directly sprayed onto any complex surface. In order to perform
a spraying, the IPMC paint solution was consisted of liquid NafionTM, viscosity controller
(Polyvinylpyrrolidone, PVP), and plasticizer (Polyethylene glycol, PEG). Modified NafionTM
solution was sprayed onto the various substrates like aluminum foil, paper, and tape. Sensing tests
show that IPMC paint sensor is capable of producing comparable voltage (- 0.6 ~ 0.4 mV) to the
typical IPMC when dynamic bent with 10 Hz sine wave and 1.3 cm displacement using shaker. The
reported research is modified from the work presented by Park et. al [1].
Finite-Strain Models of Actuation: Prestretch and Elasticity Parameters
Authors: Kofod Guggi
Published: March 2009

The cuboid actuator is presented as a simple system for evaluation of the properties of
dielectric elastomer actuators. The Ogden model as a component of this theory is evaluated and
parameters for VHB 4910 found in literature are compared. The model is presented and evaluated
with both intensive and extensive variables. For the first time direct effects of the width prestretch
on electromechanical coupling are clearly presented. Also, the importance of choosing proper
parameters for the hyper-elastic model is made clear via example.
Classification of Defects on Semiconductor Wafers Using Priority Rules
Authors: Shankar N.G. , Zhong Z.W. , Ravi N.
Published: March 2009

This paper presents a template-based vision system to detect and classify the nonuniformaties that appear on the semiconductor wafer surfaces. Design goals include detection of flaws and correlation of defect features based on semiconductor industry expert’s knowledge. The die pattern is generated and
kept as the reference beforehand from the experts in the semiconductor industry. The system is capable of identifying the defects on the wafers after die sawing. Each unique defect structure is defined as an object. Objects are grouped into user-defined categories such as chipping, metallization peel off, silicon dust
contamination, etc., after die sawing and micro-crack, scratch, ink dot being washed off, bridging, etc., from the wafer. This paper also describes the vision system in terms of its hardware modules, as well as the image processing algorithms utilized to perform the functions.
Modelling of Staebler-Wronski Effect in Hydrogenated Amorphous Silicon under Moderate and Intense Illumination
Authors: Meftah A.F. , Meftah A.M. , Merazga A.
Published: March 2009

A new model is developed for the Staebler-Wronski effect (SWE) in intrinsic a-Si:H. In this model, non-radiative recombination of the photogenerated carriers occurs at a weak bond close to a SiHHSi configuration, which allows a local creation of defect of the SiHD type. This defect can be annihilated by mobile hydrogen atom that has been emitted from an other distant SiHD defect as a result of non-radiative recombination at this defect site. In this study we have considered illumination intensities in the moderate and intense illumination range. In both cases, the proposed model reproduces many experimental features of the SWE known in
the literature.
Lithium Diffusion in Li1-2yCo1+y VO4 for Cathode Materials in Lithium-Ion Cells
Authors: Shirakawa Junichi , Ikuta H. , Uchimoto Y. , Wakihara M.
Published: March 2009

Lithium diffusion properties of Li1-2yCo1+yVO4 (y = 0, 0.05, 0.1) with inverse spinel structure as cathode materials for a Li-ion battery were investigated in view of lithium vacancies. >From galvanostatic intermittent titration technique (GITT) analysis, it is evaluated that diffusion coefficients of lithium ion DLi in Li1-xCoVO4 were decreasing from about 10-10 cm2 s-1 (x = 0.05) to 10-12 cm2 s-1 (x = 0.4), and also decreasing for Li1-2y-xCo1+yVO4 in spite of production for lithium
vacancies that is related to pre-exponential factor D0. EXAFS analysis revealed that the Debye-Waller factors which corresponded to the local distortion of each V-O and Co-O bonds were increasing by production of cation vacancies, indicating that the large local distortion of the lattice around vanadium and cobalt ions occurred. The result suggested that lithium diffusion path in these materials was disturbed by the local distortion and caused increasing the activation energy DG‡.
Fractal Self-Assembled Nanostructures on Monocrystalline Silicon Surface
Authors: Bagraev Nikolai T. , Bouravleuv A.D. , Gehlhoff W. , Klyachkin L.E. , Malyarenko A.M. , Romanov V.V. , Rykov S.A.
Published: March 2009

We present ultra-shallow diffusion profiles performed by short-time diffusion of boron
from the gas phase using controlled surface injection of self-interstitials and vacancies into the ntype Si(100) wafers. The diffusion profiles of this kind are found to consist of both longitudinal and lateral silicon quantum wells of the p-type that are self-assembled between the layers of microdefects, which are produced by previous oxidation. These layers appear to be passivated during short-time diffusion of boron thereby forming neutral d - barriers. The fractal type selfassembly of microdefects is found to be created by varying the thickness of the oxide overlayer,
which represents the system of microcavities embedded in the quantum well plane.
Diffusion Studies in Earth and Planetary Sciences
Authors: Chakraborty Sumit
Published: March 2009

The use of atomic diffusion processes to understand the origin and evolution of the Earth and other Planetary systems are briefly reviewed in this paper. I outline some situations to illustrate how diffusion modeling may find varied applications in the Earth and Planetary Sciences. Some possible areas of research are described where advances in Geosciences may benefit researchers interested in diffusion processes in other fields. These include measurement of diffusion rates under
high pressures, studies in multicomponent diffusion and modelling of diffusion and point defect related processes in multiphase and multicomponent non-metallic systems. Finally, I outline some areas where input from specialists in other areas may advance knowledge in the Geosciences.
Sedimentation of Substitutional Solute Atoms in Intermetallic Compound of Bi-Pb System under Ultra-Strong Gravitational Field
Authors: Ono Masao , Huang Xin Sheng , Kinoshita Takahiro , Ueno Hideto , Osakabe Toyotaka , Mashimo Tsutomu
Published: March 2009

Ultra-strong gravitational field can induce sedimentation of even atoms in condensed
matter. We had realized sedimentation of substitutional solute atoms in some miscible alloys. In this study, the ultra-centrifuge experiments were performed on an intermetallic compound of Bi-Pb system (Bi3Pb7) by changing time duration of experiment time (experimental conditions; maximum centrifugal force: 1.0x106g level, temperature: 130-150 °C, duration: 30-150h, state: solid). Composition changes were observed in the centrifuged samples. And, it was found that the Bi
phase appeared from starting state of Bi3Pb7 around the weak gravitational field region of the sample. These results showed that sedimentation of substitutional solute atoms occurred, and induced the structure change in intermetallic compounds.
Molecular Dynamics Study of Molecular Mobility in Catenanes
Authors: Tourleigh Ye.V. , Shaitan K.V.
Published: March 2009

Molecular machines described in this paper are meant to be such molecular systems that make use of conformational mobility (i.e. hindered rotation around chemical bonds and molecular construction deformations with formation and breakage of nonvalent bonds). Components of molecular machines move mainly by means of restricted diffusion. As an example of molecular machines of a nonbiological nature catenanes (compounds with two interlocked molecular rings)
can be proposed. Thus, for example, model catenane ((2)-(cyclo-bi (paraquat-p-phenylene))- (1(2,6)-tetrathiafulvalena-16(1,5)naphtalena-3, 6, 9, 12, 15, 17, 20, 23, 26, 29- decaoxatnacontaphane)-catenane) changes its redox status when an electric field is applied, and rotation of the rings takes place. It occurs with fixation at certain moments of the influence. To find out characteristic properties of rings movements under various external conditions molecular dynamics simulation was carried out. Three cationic forms of the catenane were first subjected to geometrical optimization and quantum chemical calculation.
Nonlinear Photo-Diffusion in Amorphous Chalcogenide Multilayers
Authors: Iván I. , Szabó I.A. , Kokenyesi S.
Published: March 2009

Enhanced intermixing, induced by a laser beam, has been recently observed in
amorphous Se/As2S3 and similar multilayers. We report a model, based on the concept of thermal spikes, which can consistently describe experimental observations. The concentration dependence of the light absorption properties causes the photo-stimulated diffusion to be non-linear even when a concentration independent coefficient of thermo-stimulated diffusion is assumed.
Peculiarities of Precipitation of Intermediate Phase in Ternary Alloys
Authors: Lutsenko G.V. , Gusak Andriy , Tu King-Ning
Published: March 2009

The growth of non-stoichiometric particles of an intermediate ternary phase during the decomposition of a weakly supersaturated solution is considered. A mathematical model which describes a non-parabolic growth of precipitates and concentrations tending to asymptotic value at long times is suggested. Shape instability during the growth of the stoichiometric ternary phase based on one of the components in the supersaturated solution is investigated.
Hysteresis in the Process of Phase Separation of Nanopowder
Authors: Shirinyan A.S. , Pasichnyy Mykola
Published: March 2009

The influence of thermodynamic constraints like the size, depletion, surface tension and kinetic constraints like energy barrier for diffusion on nonsteady separation kinetics in binary nanopowder is investigated. Here we present a numeric analysis of size hysteresis and its peculiarities using the standard kinetic equation approach.
Diffusion Measurements of 67Ga in Polycrystalline Magnesium
Authors: Stloukal Ivo , Čermák Jiří
Published: March 2009

Gallium grain boundary (GB) diffusion of Ga in polycrystalline magnesium was
investigated by radiotracer residual activity technique using 67Ga isotope. The diffusion measurements were carried out under conditions of Harrison’s B-type kinetics in temperature range 639 – 872 K. An approximate evaluation procedure was proposed to calculate both volume diffusion coefficient Dv and GB diffusivity P = s dDb (s is the segregation factor, d the GB width and Db the GB diffusion coefficient). The obtained results showed the following linear Arrhenius relationships: Dv = 1.2 × 10-4 × exp (–134.3 kJ mol-1/RT) m2 s-1 and P = 3.8 × 10-9 × exp (–94.9 kJ mol-1/RT) m3 s-1, where R is universal gas constant and T the temperature. Obtained results were compared with literature data on Mg self-diffusion and with In impurity diffusion in magnesium.
3D-Simulation of Void Formation, Growth and Migration under Electromigration
Authors: Zaporozhets T.V. , Sobchenko I.V. , Gusak Andriy
Published: March 2009

The 3D Monte Carlo scheme is proposed for simulation of simultaneous self-consistent current redistribution, surface diffusion, drift and void migration and coalescence at the interface metal/dielectric. Results of simulation as well as simple phenomenological model demonstrate a possibility of trapping at and migration along the grainboundaries (GBs). Critical size of “detrapping” after coalescence has been estimated.
Zinc Self-Diffusion in ZnO
Authors: Nogueira M.A.N. , Sabioni Antônio Claret Soares , Ferraz Wilmar Barbosa
Published: March 2009

This work deals with the study of zinc self-diffusion in ZnO polycrystal of high density and of high purity. The diffusion experiments were performed using the 65Zn radioactive isotope as zinc tracer. A thin film of the tracer was deposited on the polished surface of the samples, and then the diffusion annealings were performed from 1006 to 1377oC, in oxygen atmosphere. After the diffusion treatment, the 65Zn diffusion profiles were established by means of the Residual Activity Method. From the zinc diffusion profiles were deduced the volume diffusion coefficient and the
product dDgb for the grain-boundary diffusion, where d is the grain-boundary width and Dgb is the grain-boundary diffusion coefficient. The results obtained for the volume diffusion coefficient show good agreement with the most recent results obtained in ZnO single crystals using stable tracer and depth profiling by secondary ion mass spectrometry, while for the grain-boundary diffusion there is no data published by other authors for comparison with our results. The zinc grain-boundary
diffusion coefficients are ca. 4 orders of magnitude greater than the volume diffusion coefficients, in the same experimental conditions, which means that grain-boundary is a fast path for zinc diffusion in polycrystalline ZnO.
Software for Simulation of Diffusion Process in Polycrystalline Material
Authors: Li Hua Long , Szpunar Jerzy A.
Published: March 2009

Understanding of diffusion processes in polycrystalline solids is of importance for studying processes like oxidation, precipitation, creep, superplastic forming, annealing and many other processes. In this paper, we will introduce our latest software that is able to simulate the diffusion process in poly and nano-crystalline solids. The diffusion process is simulated based on Random Walk theory. The diffusion matrix can be computer generated or obtained from the experimental measurement using Orientation Imaging Microscopy. The software describes microstructure and incorporates the effects of the material’s texture, grain size and shape, grain boundary character distribution, statistical information on CSL boundary distributions, contribution from triple junctions and interfaces, the trapping of diffusing atoms and interaction of atoms with second phases and voids. A built-in database of diffusivities of various diffusing species and the user friendly interface make the software easy to use. The software is also applicable to thin films and multilayer structures. The output of simulation can be presented as a normalized concentration profile, a two-dimensional contour map of diffusing species, and also using many other statistical representations.
Inverse T-Sample Method of Determination of the Interdiffusion Coefficients in the Cu-Ni-Sn System
Authors: Lyashenko Yu.A. , Bogdanov V.V.
Published: March 2009

A method of the determining of the mutual diffusion coefficients in ternary intermediate
phases is suggested. Methodology for determination of the interdiffusion coefficients of phases formed in a ternary diffusion couple in T-sample configuration is presented. The method requires only one annealing of the T-sample and makes it possible to calculate the matrix of the diffusion coefficients in the (CuNi)6Sn5 and Cu3Sn ternary intermediate phases under low temperature. The concentration profiles and electron micrograph of the diffusion zone was obtained in the ternary
Cu-Ni-Sn system annealed for 64 hours under 200°C. Phase competition in this ternary system with special configuration of T-sample leads to lateral diffusion of Cu, to formation (CuNi)6Sn5 compound between Ni-Sn side and to suppression of other NixSny intermediate phases.
Modelling of Interdiffusion and Reactions at the Boundary; Initial-Value Problem of Interdiffusion in the Open System
Authors: Filipek Robert
Published: March 2009

The application of the Danielewski-Holly model of interdiffusion for modelling of
selective and concurrent oxidation of multi-component alloys is presented. This model enables prediction of the evolution of components distributions taking into account interdiffusion and the reactions at the boundary, e.g, due to the oxidation/sulphidation processes. The model is subsequently reformulated to the form suitable for numerical calculation. For illustrating its capabilities modelling of the selective oxidation of Ni-Pt alloys is presented. The results are compared with those obtained from Wagner model. Both models give exactly the same results for the longer reaction times. In Wagner model the equilibrium concentration of the elements at the boundary is reached instantly while in this model it changes with time. Consequently the model allows modelling of initial stages of oxidation.
Tracer Diffusion and Ionic Conduction in Standard Silica Glasses
Authors: Tanguep Njiokep Eugene M. , Mehrer Helmut
Published: March 2009

The tracer diffusivities of 22Na and 45Ca in two high-quality standard silica glasses have been measured in the temperature range between 473 and 783 K. The temperature dependences of the tracer diffusion coefficients in both glasses follow Arrhenius laws. The diffusion of 22Na is six to seven orders of magnitude faster than the diffusion of 45Ca. The ionic conductivity was determined by impedance spectroscopy and the conductivity diffusion coefficient Ds was deduced from the dc conductivity via the Nernst-Einstein relation. The temperature dependences of Ds for both glasses follow also Arrhenius functions. The activation parameters and pre-exponential factors for tracer diffusion and for conductivity diffusion were determined. The activation enthalpy of 22Na diffusion is almost equal to the activation enthalpy of the dc conductivity. We conclude that the conductivity of standard glasses is due to the motion of Na ions. The diffusivities of 22Na and 45Ca in soda-lime glasses increase with increasing Na2O content.
Unified Simulation of Diffusion in Silicon and Silicon Dioxide
Authors: Uematsu Masashi
Published: March 2009

We present a unified simulation of diffusion in silicon (Si) and silicon dioxide (SiO2) that is based on the diffusing dopant species and point defects that primarily contribute to the diffusion. We first present the simulation of phosphorus (P) diffusion in Si based on the integrated diffusion model that we have developed and elucidate the mechanism of the appearance of the anomalous P in-diffusion profile. The vacancy mechanism governs P diffusion in the plateau region, while the kick-out mechanism governs it in the deeper region, where Si self-interstitials dominate in the kink region and P interstitials dominate in the tail region. Next, we present the simulation of boron (B) diffusion and Si self-diffusion in SiO2. We examined the co-diffusion of implanted B and 30Si in thermally grown 28SiO2, which shows increasing diffusivities with decreasing distance between the diffusers and Si/SiO2 interface and with higher B concentration in SiO2. We propose a model in which SiO molecules generated at the interface and diffusing into SiO2 enhance both B diffusion and Si self-diffusion. The simulation showed that the SiO diffusion
is so slow that the SiO concentration at the B and 30Si region critically depends on the distance from the interface. In addition, the simulation predicts the possibility of time-dependent diffusivities for B and Si because more SiO molecules should be arriving from the interface with time, and this time dependence was experimentally observed. Moreover, based on the B concentration dependence, the simulation result indicates that B and Si atoms in SiO2 diffuse correlatively via SiO; namely, the
enhanced SiO diffusion by the existence of B enhances B diffusion and Si self-diffusion.
Lanthanide Diffusion in Single Crystalline and Polycrystalline Pure or Yttrium Doped Alpha-Alumina
Authors: Legros Corinne , Lesage Bernard , Borchardt Günter , Kilo Martin , Jomard François
Published: March 2009

In order to bring a contribution to cationic diffusion in alpha-alumina, results on diffusion of 14 lanthanides and Y are presented. Samples are either single crystals with a known orientation or polycrystals with various grain-sizes elaborated from Y-doped alumina powders (100 ppm or 1000 ppm) or from pure alumina powder. After pre-heating in air at the diffusion temperature, small drops of a solution containing these elements are deposited at the surface of the sample. After the
diffusion treatment (1200°C, 48 h or 1300°C, 21h), the diffusion profiles are obtained by a CAMECA IMS 4F SIMS device. The isotopes which are taken in account are: 45Sc, 89Y, 139La, 140Ce, 141Pr, 146Nd, 147Sm, 153Eu, 158Gd, 159Tb, 163Dy, 165Ho, 166Er, 169Tm, 174Yb and 175Lu which are the most suitable for this analysis. At first, it can be observed that the diffusion profiles are quite the same for all lanthanides. Diffusion profiles obtained for single crystals allow to calculate the lattice diffusion coefficients, which are necessary to determine the diffusion coefficients values in grain boundaries. Lattice and grain-boundary diffusion coefficients values are compared with cationic diffusion coefficients determined earlier.
Interdiffusion and Al Self-Diffusion in Iron-Aluminides
Authors: Salamon Marcel , Fuks David , Mehrer Helmut
Published: March 2009

We have investigated interdiffusion in iron-aluminium alloys using single-phase interdiffusion couples of FexAl1−x–FeyAl1−y for three combinations of x and y for Al contents between 18 and 49.5 at. % Al. Experimental diffusion profiles were obtained from electron-microprobe analysis of the diffusion zone. Interdiffusion coefficients were deduced via the Sauer-Freise method taking into account volume changes. A temperature interval between 997 and 1447 K was covered in our experiments. Thermodynamic factors were obtained from two theoretical models and
judged by an analysis of the Kirkendall effect in the diffusion couples. The Darken-Manning equation was used to deduce self-diffusion coefficients of aluminium from the present interdiffusion coefficients, the thermodynamic factors, the vacancy-wind factors, and the iron tracer diffusivities obtained recently at the M¨unster laboratory. The results show that Al diffusion is always slightly faster than Fe diffusion. The difference never exceeds a factor of three. This small difference indicates that Fe and Al diffusion in B2 ordered iron-aluminides are closely coupled.
Chemical Diffusion in TiO2
Authors: Radecka M. , Rekas M.
Published: March 2009

Chemical diffusion in TiO2-x within n - p transition regime has been studied. In this regime several point defects such as oxygen vacancies, • • O V , titanium interstitials, • • • i Ti and • • • • i Ti , electrons, ' e , and electron holes • h are present with comparable concentrations. Based on defect structure in TiO2-x the relationship between chemical diffusion coefficient and self-diffusion coefficients of both titanium and oxygen were deduced.
Enhanced Diffusional Self-Healing of Polycrystalline Thin Films
Authors: Rabkin Eugen , Klinger Leonid
Published: March 2009

We considered the flattening of perturbed surface of a thin stress-free polycrystalline film with columnar microstructure deposited on rigid substrate. We show that the mass transport along the film/substrate interface and along the grain boundaries significantly contributes to the overall rate of surface flattening of the film. The diffusion along the film/substrate interface and along the grain boundaries is driven by the capillary stresses in the film. Using the approximation of small surface slopes, we calculated the distribution of capillary stresses in the film, and derived an explicit expression for the temporal behavior of the film topography. The initial distribution of the capillary stresses rapidly relaxes to the steady-state one that does not allow the accumulation of bending strain in the film. For the films with passivated or contaminated surfaces exhibiting reduced surface diffusivity the interfacial and grain boundary diffusion play a leading role in kinetics of surface
flattening. The flattening process can be accelerated in this case by several orders of magnitude. The results of our work can be helpful in design of thin films and coatings with enhanced selfhealing capabilities.
Diffusion Impurity Drag of Twin Grain Boundaries and Triple Junctions Motion in Zinc
Authors: Sursaeva Vera G. , Zięba Paweł
Published: March 2009

The experimental results on motion of single grain boundaries (GBs) of natural
mechanical twin and single fabricated twin GBs as well as on fabricated twin GBs in system with triple junction (TJ) are obtained. The mobility of natural mechanical twin GBs, fabricated single GBs and fabricated GBs with TJ are compared. For the first time the effect of detachment of moving TJ and single natural twin GB from adsorbed atoms is reported. The results on single GB migration are considered in context of triple junction migration as the step to grain growth, i.e. “polycrystal” experiments.
Computer Simulation of Phase Decomposition in Magnetic Materials Based on the Phase-Field Method
Authors: Koyama Toshiyuki
Published: March 2009

During the last decade, the phase-field method has emerged across many fields in materials science as a powerful tool to simulate and predict complex microstructure evolutions. Since phase-field methodology has an ability to model complex microstructure changes quantitatively, it will be possible to search for the most desirable microstructure by using this method as a design simulation, i.e. through computer trial-and-error testing. In order to establish this methodology, the flexible quantitative modeling for various types of complex microstructure changes using the phase-field method must first be needed. In this study, as the typical examples for the modeling of the complex microstructure changes using phase-field method, recent simulation results for the diffusion controlled phase transformations and microstructure developments in magnetic materials are demonstrated.