bluuebunny/crossref_metadata_2025 huggingface dataset:
Oxidation Behavior of TiAl3 Formed in Ti/Al Diffusion Couple and Reaction Diffusion in Ti/TiAl3 Multi-Phase Diffusion Couple
Authors: Shimozaki Toshitada , Takasaki Kenichi , Okino Takahisa , Lee C.G.
Published: March 2009

Oxidation resistance of TiAl3, one of the candidates of coating materials for high
temperature structural materials such as Ti3Al and TiAl, has been studied. Specimens were prepared
by forming TiAl3 in Al/Ti/Al reaction diffusion couples at 923 K and then TiAl3 layer was exposed
to air by dissolving Al plate in a 1N NaOH solution. The obtained TiAl3/Ti/TiAl3 couples were
annealed in air in the temperature range from 1173 K to 1468 K. The oxidation rate was compared
with that determined by using bulk TiAl3. The present data show a bend on the Arrhenius plot of
parabolic phase growth rate constant, k2, at 1323 K. Above 1323K, the constant coincides well with
the extrapolated values of bulk data while the value in the lower temperature range is larger than
that of bulk specimens.
During the oxidation experiments, intermetallic compounds Ti3Al, TiAl and TiAl2 were formed
between Ti and TiAl3. Interdiffusion coefficients in the Ti3Al, TiAl phases determined from these
diffusion couples are more than one order of magnitude larger than the interdiffusion coefficients
determined by previous investigators from single-phase diffusion couples but coincide with the
coefficients determined from multi-phase diffusion couples. This difference between interdiffusion
coefficients has been discussed and explained by the effect of boundary diffusion in the diffusion
layers formed in the multi-phase diffusion couples.
Ad- and Desorption of Oxygen at Metal-Oxide Interfaces: Numerical Approach for Concentration-Dependent Diffusion Coefficient
Authors: Stasiek M. , Öchsner Andreas
Published: March 2009

A numerical approach for the segregation of atomic oxygen at Ag/MgO interfaces
is presented. A general segregation kinetics is considered and the coupled system of differ-
ential equations is solved due to a one-dimensional finite difference scheme which accounts
for concentration-dependent diffusion coefficients. Based on a model oxide distribution, the
influence of the concentration-dependency is numerically investigated and compared with the
solution for constant coefficients. In addition, the numerical approach allows for the consider-
ation of general boundary conditions, specimen sizes and time-dependent material and process
parameters.
High-Pressure Influence on the Kinetics of Grain Boundary Segregation in the Cu–Bi System
Authors: Chang L.S. , Straumal Boris B. , Rabkin Eugen , Łojkowski Witold , Gust W.
Published: March 2009

The effect of pressure on the kinetics of grain boundary (GB) segregation in the Cu–50 at.
ppm Bi alloy has been studied. It was found by means of Auger electron spectroscopy that at a
temperature of 1173 K the segregation level decreases from 2 to 1.5 monolayer as the pressure
increases from 0.01 to 1.2 GPa. This behavior was explained by considering the physical parameters
controlling kinetics and thermodynamics of GB segregation. A simplified model based on dislocation
pipe diffusion, proposed previously and discussed in more details in this work, was used to calculate
the non-equilibrium GB segregation during cooling under high pressure. The pressure effect on bulk
diffusion is responsible for the suppression of GB segregation, while the pressure effect on the phase
stability in Cu–Bi alloys provides a negligible contribution on GB segregation in the pressure range
studied.
Three-Group Albedo Method Applied to the Diffusion Phenomenon with Up-Scattering of Neutrons
Authors: Terra André Miguel Barge Pontes Torres , da Silva Jorge Alberto Valle , Cabral Ronaldo Glicério
Published: March 2009

The main objective of this research is to develop a three-group neutron Albedo algorithm
considering the up-scattering of neutrons in order to analyze the diffusion phenomenon in nonmultiplying
media. The neutron Albedo method is an analytical method that does not try to solve
explicit describing equations for the neutron fluxes [1,2]. Thus the neutron Albedo methodology is
very different from the conventional methodology, as the neutron diffusion theory model. Graphite
is analyzed as a model case. One major application is in the determination of the nonleakage
probabilities with more understandable results in physical terms than conventional radiation
transport method calculations.
The Influence of Post-Quenching Deep Cryogenic Treatment on Tempering Processes and Properties of D2 Tool Steel. Studies of Structure, XRD, Dilatometry, Hardness and Fracture Toughness
Authors: Wierszyłłowski Ignacy
Published: March 2009

A significant increase in durability of cryogenically treated tools after quenching was
reported by a number of publications [1, 2]. As research studies show [4, 5, 6, 7], the main reason
for this is the kind of carbides precipitated during tempering at temperature range of 150 –200 0C,
which is different than in the case of conventional treatment. These carbides are finer and more
evenly distributed in the matrix of steel. The number of carbides is higher than in conventionally
treated steels because of higher fraction of martensite in cryogenically treated steels produced by
retained austenite transformation at cooling to deep cryogenic temperatures. The number of
carbides precipitated from martensite at low temperatures of tempering is proportional to shrinkage
produced at the same temperatures of tempering. Calculations on the basis of dilatometric
experiments show that the shrinkage difference between the same D2 steel cryogenically and
conventionally treated is higher than that which results from the increased fraction of martensite in
cryogenically treated steel. The XRD studies of cryogenically treated steel show a presence of two
kinds of martensites differing in tetragonality. Low temperature tempering of cryogenically treated
steel produced two types of carbides – ε carbide and η carbide. The conventionally treated steel
consists of one kind of tetragonal martensite and one kind of carbide - the ε carbide. The hardness
of cryogenically treated samples was somewhat higher than in conventionally treated ones, while
fracture toughness of conventionally treated samples was somewhat higher than in cryogenically
treated ones. The results obtained were discussed in reference to literature data.
Two-Phase Hygrothermal Diffusion in an Epoxy Adhesive
Authors: Popineau Sylvain , Rondeau-Mouro C. , Sulpice-Gaillet Christine , Shanahan Martin E.R.
Published: March 2009

Water diffusion in polymers can often be approximated by a Fickian description, but a 2-
phase model was proposed some years ago by Carter and Kibler (C&K), often referred to as “Langmuirtype”
diffusion, by analogy with the Langmuir theory of adsorption. The two phases in question
correspond to “mobile” and “bound” diffusant molecules.
In this study, we have considered water uptake in an epoxy resin (an adhesive), employing
gravimetry. A good, overall, empirical agreement with the C&K mathematical description of total mass
increase with time has been obtained. In many applications of the C&K theory when used to quantify
diffusion of water in polymers, only total water uptake is considered as a datum. However, a simple
mathematical treatment of the theory enables the separate mobile and bound contributions to be isolated.
These supplementary data have been used to try to get a better understanding of the meaning of the terms
“mobile” and “bound” phases.
Deuterium NMR analysis has been employed to study the mobility of the absorbed water.
Decomposition of spectra has permitted us to assign two signals to the fractions of “mobile” and
“bound” water. Analysis of peak evolution and a comparison with gravimetric data lead us to suggest
that the “mobile” phase corresponds to diffusing molecules, whereas the “bound” phase corresponds to
“clusters”.
Phenomenological Aspects of Grain Boundary Diffusion
Authors: Belova Irina V. , Murch Graeme E.
Published: March 2009

In this paper, the authors review recent progress that has been made in understanding
various aspects of grain boundary diffusion at the phenomenological level. We show how the
mapping of phenomenological grain boundary diffusion problems onto a lattice readily permits
lattice-based random walk theory to be used to address the problem, invariably by Monte Carlo
computer simulation methods. Recent advances in calculating concentration profiles and effective
diffusion coefficients are described in detail.
Classical Molecular Dynamics Simulation of Structural and Dynamical Properties of II-VI and III-V Semiconductors
Authors: Rino José Pedro , Branício Paulo S. , Borges Denílson S.
Published: March 2009

An effective inter-atomic potential is proposed in order to describe structural and
dynamical properties of II-VI and III-V semiconductors. The interaction potential consists of twoand
three-body interactions. The two-body term takes into account steric repulsion, charge-induce
dipole interaction due to the electronic polarizability of ions, Coulomb interaction due to charge
transfer between ions, and dipole-dipole (van der Waals) interactions. The three-body term, which
has a modified Stillinger-Weber form, describes bond-bending as well as bond-stretching effects.
Here we report the fitting and the application of this interaction potential for InP in the crystalline
phase and for CdTe in the crystalline and liquid phases. The structural correlations are discussed
through pair distribution, coordination number and bond-angle functions. Vibrational density of
states for InP and CdTe as well as the static structure factor for liquid CdTe are in very good
agreement with experimental data.
Electronic structure and doping effect of Ni and Co in the kink on the edge dislocation of bcc iron
Authors: Chen Li Qun , Qiu Zheng Chen
Published: March 2009

Using the first-principles self-consistent discrete variational method based upon density functional theory, we investigated the energetics and the electronic structure of the 3d impurities Ni and Co in a kink on the [100](010) edge dislocation (ED) in bcc iron. The calculated results show that the interatomic energies between the impurity atom and the neighboring host atoms decrease. The bonding for the impurity atom (Ni, Co) and the neighboring host Fe atoms is weaker than that for an Fe atom at the X site and the corresponding atoms in the clean kink. These results indicate that sideways motion of the kink in the <100>{010} ED is accelerated by an impurity atom such as Ni or Co and that, consequently, the presence of impurities increases the dislocation mobility, thus leading to solid-solution softening.
Kinetic and Thermodynamic Aspects of High-Temperature Oxidation of Selected Ti-Based Alloys
Authors: Vojtech Dalibor , Mort'aniková M. , Novák Pavel
Published: March 2009

In the presented work, high-temperature cyclic oxidation of pure Ti, Ti-7.8wt.%Si, Ti-
45.6wt.%Al and Ti-11.7wt.%Al-7.2wt.%Si alloys at 750 – 1050 °C in air were studied. It was
found that both Si and Al strongly reduce the oxidation rate of titanium, mainly up to 850 °C. They
incorporate into the oxide scales and reduce penetration rate of oxygen towards the metallic
substrate. Mechanism of the barrier effects of the elements is discussed with respect to their
distribution in alloys. It was observed by comparison of Al-containing and Si-containing alloys, that
the influence of Si on the oxidation kinetics is significantly stronger. It can be supposed that a
synergic effect of silicon and nitrogen is a reason for this behavior.
Zn Diffusion in Binary Base of Light Mg-Al Alloys
Authors: Čermák Jiří , Stloukal Ivo
Published: March 2009

Heterodiffusion of 65Zn in Mg, Mg – x Al (x = 1.77, 3.9 and 9 wt.% Al) and in the
commercial AZ91 alloy was studied in the temperature interval 498 – 848 K by serial sectioning
and residual activity methods. The concentration and temperature dependence of Zn bulk diffusion
coefficient D is described by the relation D = exp (0.1 × cAl – 9.16) × exp (-125.8 kJ mol-1/RT) m2
s-1 (cAl – concentration of Al in wt.%). Zn grain boundary diffusivity P = s δ Db (s – segregation
factor, δ - grain boundary width and Db – diffusion coefficient in grain boundary) was also
determined and it was found that it obeys the Arrhenius law P = 7.2 × 10-15 × exp (-46 kJ mol-1/RT)
m3 s-1.
Simulation of Precipitates Evolution in Steels
Authors: Popov Vladimir V. , Gorbachev I.
Published: March 2009

The model describing the behavior of precipitates of variable composition at heat
treatment is suggested. The specific feature of this model is that it enables to take into account the
effect of diffusion inside the particles on the kinetics of the process. The application of this model is
demonstrated by the example of vanadium carbonitrides V(C,N) evolution in austenite at heat
treatment of vanadium-containing steels. The necessity to take into account the diffusion
modification of carbonitride composition is considered. Examples of particles composition
evolution at heat treatment are demonstrated.
Diffusion of Zinc in Two-Phase Mg-Al Alloy
Authors: Stloukal Ivo , Čermák Jiří
Published: March 2009

Coefficient of 65Zn heterodiffusion in Mg17Al12 intermetallic and in eutectic alloy Mg -
33.4 wt. % Al was measured in the temperature region 598 – 698 K using serial sectioning and
residual activity methods. Diffusion coefficient of 65Zn in the intermetallic can be written as DI =
1.7 × 10-2 m2 s-1 exp (-155.0 kJ mol-1 / RT). At temperatures T ≥ 648 K, where the mean diffusion
path was greater than the mean interlamellar distance in the eutectic, the effective diffusion
coefficient Def = 2.7 × 10-2 m2 s-1 exp (-155.1 kJ mol-1 / RT) was evaluated. At two lower
temperatures, the diffusion coefficients 65Zn in interphase boundaries were estimated: Db (623 K) =
1.6 × 10-12 m2 s-1 and Db (598 K) = 4.4 × 10-13 m2 s-1.
Spatially Periodic Formation of Nanoparticles in Metal-Doped Glasses
Authors: Kaganovsky Yuri S. , Lipovskii A.A. , Rosenbluh M. , Zhurikhina V.
Published: March 2009

In the course of reactive diffusion of hydrogen in metal-doped glasses, at some
conditions, metallic nanoparticles grow forming quasi-periodic layered structure. We have
developed a model defining conditions necessary for the formation of the layered structures. The
model indicates relatively narrow range of parameters providing the quasi-periodic growth of the
nanoparticles. The layered structure arises at relatively low over-saturation by neutral metal in the
diffusion zone, due to the competition of two processes: enrichment of the glass by neutral metal
atoms via reducing of metal ions by diffusing hydrogen and depletion of the glass by the metal
atoms caused their diffusion to the nanoparticles. The model can be also applied to other situations
where reactive diffusion inducing the formation and growth of nanoparticles occurs.
NGR Investigation of Grain-Boundary Diffusion in Poly- and Nanocrystalline Nb
Authors: Popov Vladimir V. , Kaigorodov V.N. , Popova E.N. , Stolbovsky A.V.
Published: March 2009

The properties of grain boundary cores and adjacent areas in polycrystalline Nb
manufactured by rolling with subsequent recrystallization annealing and nanocrystalline Nb
obtained by high pressure torsion have been investigated by the Mössbauer emission spectroscopy
on 119mSn nuclei.
Investigating Interdiffusion in Mo/V Multilayers from X-Ray Scattering and Kinetic Simulations
Authors: Benoudia M.C. , Roussel Jean Marc , Labat Stephane , Thomas O. , Beke Dezső L. , Langer G.A. , Kis-Varga Miklos
Published: March 2009

In order to investigate interdiffusion in Mo/V multilayers, we present a method that
combines both kinetic mean-field simulations and calculations of x-ray scattered intensity with
disorder effects. Considering preliminary experimental data obtained on Mo(4nm)/V(2nm)
multilayers, we show that the angular shift of spectra observed after annealing, should take place for
both Fickian and asymmetric interdiffusion modes. In contrast, clear signatures of the interdiffusion
modes are found from the simulation of the peak intensities. These results offer interesting
perspectives for a full analysis of the interdiffusion in these systems.
Influence of Annealing Environment and Film Thickness on the Phase Formation in the Ti/Si(100) and (Ti +Si)/Si(100) Thin Film Systems
Authors: Makogon Yu.N. , Pavlova O.P. , Sidorenko Sergey I. , Beddies G. , Mogilatenko A.V.
Published: March 2009

Influence of an annealing environment and film thickness on the phase formation in the
Ti(30 nm)/Si(100), [(Ti+Si) 200 nm]/Si(100) thin film systems produced by magnetron sputtering
and the Ti(200 nm)/Si(100) thin film system produced by electron-beam sputtering were
investigated by X-ray and electron diffraction, Auger electron spectroscopy (AES), secondary ion
mass-spectrometry (SIMS) and resistivity measurements. Solid-state reactions in the thin film
systems under investigation were caused by diffusion processes during annealing in the different
gas environments: under vacuum of 10-4 - 10-7 Pa, flow of nitrogen and hydrogen. It is shown that
the decrease of Ti layer thickness from 200 to 30 nm in the Ti/Si(100) film system causes the
increase of the transition temperature of the metastable C49 TiSi2 phase to the stable C54 TiSi2
phase up to 1070 K at vacuum annealing. During annealing in the nitrogen flow of the Ti(30
nm)/Si(100) thin film system the C49 TiSi2 is the first crystal phase which is formed at 870 K. For
annealings of the [(Ti+Si) 200 nm]/Si(100) thin film system by impulse heating method or for
furnace annealings in inert gas atmosphere of N2, Ar, H or higher vacuum (10-5 Pa) the
crystallization process has two stages: the first metastable C49 TiSi2 phase is formed at 870 K and
then at higher temperatures it is transformed to the stable C54 TiSi2 phase.
Effect of Morphology on the Mobility of Nanosized Liquid Pb Inclusions in Solid Al
Authors: Prokofjev S.I. , Zhilin V.M. , Johnson E. , Dahmen U.
Published: March 2009

Diffusion of nanosized liquid Pb inclusions attached to dislocations in thin aluminum
foils was investigated in a wide temperature range using in-situ transmission electron microscopy.
Trajectories of motion of the inclusions along the dislocations were used to determine their
diffusion coefficients. The temperature and size dependences of diffusion coefficients of the
inclusions were obtained. They indicate that
(i) studied inclusions hold {111} facets on their surface in the studied temperature range;
(ii) the mobility of the inclusions is controlled by step nucleation at the {111} facets.
Cross Diffusion-Stresses Effects
Authors: Bokstein Boris S. , Epishin Alexander , Esin Vladimir , Mendelev Mikhail , Rodin Alexey , Zhevnenko Sergei
Published: March 2009

Three cross diffusion-stresses effects are considered: mobility-stress effect, flux-stress
effect and vacancy-stress effect. The value of the migration volume for vacancies in Al is found
from atomistic computer simulation. A cross vacancy-stress effect is applied to the process of the
pores growth and dissolution in Ni-based superalloys.
Nanoscale Effects in Interdiffusion
Authors: Erdélyi Z. , Langer G.A. , Csik A. , Beke Dezső L.
Published: March 2009

Diffusion on the nano/atomic scales in multilayers, thin films has many challenging
features even if the role of structural defects can be neglected and ‘only’ the effects related to the
nano/atomic scale raise. Different examples for diffusional nanoscale effects we have discovered
recently will be summarized in this paper. We illustrate that the continuum descriptions of the
diffusion cannot be applied automatically on such short distances, the classical continuum
approximations (Fick's laws) cannot describe correctly the atomic movements. [1-4] They predict
faster kinetics than the atomistic models and the interface shift is always proportional to the squareroot
of the time (x ∝ t1/2 ⇒ x2 ∝ t: parabolic or Fickian kinetics). However, the kinetics can be even
linear (x ∝ t) on the nano/atomic scale. [3, 4] Furthermore, the continuum descriptions foretell
infinitely fast kinetics as the time goes to zero (v=dx/dt∝1/t1/2), which is a long standing paradox of
the diffusion theory. Very recently a possible resolution of this paradox has been offered [5],
moreover, it was also shown that an initially diffused interface can sharpen even in completely
miscible systems. [6, 7] We will also review the possible stress effects on the above phenomena.
An Examination of Diffusion Paths in Terms of Interdiffusion Fluxes and Interdiffusion Coefficients
Authors: Day Kevin M. , Dayananda Mysore A.
Published: March 2009

Selected diffusion couples investigated in the Cu-based and Fe-based multicomponent systems are examined for diffusion path development, zero-flux planes, uphill diffusion, and internal constraints for diffusion paths. The couples are analyzed for interdiffusion fluxes and interdiffusion coefficients with the aid of the “MultiDiFlux” program. Eigenvalues and eigenvectors are also determined from the interdiffusion coefficients determined over various ranges of composition in the diffusion zone. Slopes of diffusion paths at selected sections, including the path ends, are related to interdiffusion coefficients, interdiffusion fluxes and/or eigenvectors. These relations are explored with selected single phase diffusion couples in the Cu-Ni-Zn and Fe-Ni-Al systems and the calculated path slopes are compared with those directly determined from the concentration profiles. Relations between the gradient of interdiffusion flux and the concentration gradient are examined for each component in a two-phase Cu-Ni-Zn diffusion couple. The research is supported by the National Science Foundation.
Matrix Description of Some Thermodynamic Properties of Multicomponent Alloys in Explicit Form
Authors: Erokhin L.I.
Published: March 2009

A matrix method for description of some thermodynamic properties in multicomponent
alloys in explicit form has been proposed. It has been found that the method for determining
thermodynamic properties from the cross-section data allows to find the contribution of short-range
ordering into the thermodynamic state of an imperfect alloy.
Diffusion processes in alloys are formed both from purely kinetic migrations of particles and
from the system's thermodynamic properties. A consequence of this fact is that the diffusion
coefficients D in all systems except for perfect solid solutions include to factors being
D = Lg ,
the second one is the thermodynamic factor directly related to the system's chemical potential.
However direct experimental separation of these factors can easily be performed in binary systems
only while in triple systems in is highly difficult let alone multicomponent systems.
Experimental evaluation of the factors in multicomponent systems from short-range order's
parameters [1] would allow to establish a relation between the system's thermodynamic properties
which is highly important for further progress in multicomponent diffusion theory and for practical
applications.
Theoretical Determination of Pressure-Volume-Temperature Relationship of Some Alkali Halides
Authors: Liu Quan
Published: March 2009

The Chopelas-Boehler approximation for the volume dependence of the
Anderson-Gruneisen parameter along isotherms and the new approximation for the volume
dependence of the Anderson-Gruneisen parameter along isobars have been used to study the
pressure-volume-temperature relationship for LiF, NaF and CsCl crystals up to a pressure of 90kbar
and in the temperature range 298-1073K. The calculated values of compression data and
experimental values are found to be in good agreement.
Structure and Optical Properties of Magnetron Sputtered SiOx Layers with Silicon Nanoparticles
Authors: Khomenkova L. , Korsunska N. , Stara T. , Goldstein Y. , Jedrzejewski J. , Savir E. , Sada C. , Emirov Y.
Published: March 2009

The properties of SiOx layer prepared by magnetron sputtering is studied by photoluminescence
Auger and SIMS methods. The depth distribution of emission characteristics and chemical
composition is obtained. It is shown that as-sputtered SiOx layers are non-emitted and characterized
by homogeneous enough chemical composition. High-temperature annealing in nitrogen
atmosphere stimulates not only the Si nanocrystal formation but also the redistribution of silicon
and the appearance of Si depleted region near layer-substrate interface. The last process is found to
be dependent on excess Si content. It is found that decrease of silicon content in the depth of
annealed layers is followed by the decrease of particle sizes that is proved by the blue shift of
photoluminescence maximum. The possible reasons of the appearance of Si depleted region are
discussed.
Phase Stability in Hydroxyapatite / Barium Titanate Piezo Bioceramics
Authors: Aba Arda , Ergun Celaletdin
Published: March 2009

It has been reported in the biocompatibility researches performed in-vivo and in-vitro that
the electric signals produced by piezoelectric implants may induce accelerated healing of the injured
tissue after implantation. Barium titanate (BaTiO3; BTO), as a well known piezoelectric ceramic, is
a suitable candidate to be used in these kind of biomedical researches about the effect of the
electrical polarity and piezoelectricity on tissues. The excellent biocompatibility and faster bone
adaptation characteristics of hydroxylapatite (HA) have been well documented in the literature.
Therefore, HA / BTO composites may be a suitable bioceramic material introducing both the piezo
effect and biocompatibility at the same time. However, the main point to process such composites
should be to keep HA and BTO phases as stable as possible not to loose the biocompatibility of HA
and the piezoelectricity of BTO ceramics. In this research HA / BTO, piezo-composites were
prepared with powder mixing method in various mixing ratios and sintered at the temperatures
between 500 and 1300 oC. Sintering was carried out under different atmospheres to evaluate the
effect of atmosphere on the phase stability of composites. Then composites are characterized with
XRD, DTA, density measurements and d33 piezoelectricty coefficient measurements.
Boundary Conditions in the Diffusion of Fluids in Swelling Polymers
Authors: Durier Anne Lise , Derrien Katell , Gilormini Pierre
Published: March 2009

Diffusion of fluids in polymers may lead to swelling, which induces stress-diffusion
coupling. A simple coupling model is considered, where boundary conditions only are altered, and
it leads to a sigmoidal water-uptake curve for a plate in water. Several other models are studied,
which are able to induce similar sorption curves by using various boundary conditions, but
comparisons between other predictions of the models reveal significant differences. Eventually,
none of the models considered is able to reproduce all features of the coupling model.
Effect of Synthesis Temperature on the Morphology of ZnO Nanoparticles Obtained via a Novel Chemical Route
Authors: Samei Javad , Shokuhfar Ali , Esmaielzadeh Kandjani A. , Vaezi Mohammad Reza
Published: March 2009

ZnO as a semiconductor is used in many applications such as gas sensor devices,
laser and optoelectronic devices, photocatalysts, solar cells, and varistors. The applications
and properties of ZnO nanoparticles highly depend on the size and morphology of these
particles. In this research ZnO nanoparticles were prepared via chemical bath deposition at
various temperatures in order to see the effects of synthesis temperature and also 2-
methoxyethanol (2-ME) as a novel solvent on the morphology of obtained nanoparticles. For
synthesizing of ZnO nanostructured materials, 2-ME has been highly used in sol-gel process
but it is the first time that it is used in the chemical bath deposition process. For this purpose 1
M solutions of zinc acetate dehydrate in 2-ME were prepared and added to the solution of
NaOH in the same solvent dropwisely. Monoethanolamine (MEA) was used as surfactant.
The synthesis temperatures were 30°C, 60°C and 90°C. After filtering and drying,
morphologies of obtained nanoparticles were characterized and compared.
Investigation of Reaction Conditions on Alcohol-Thermal Synthesis of ZnO Nanoparticles
Authors: Esmaielzadeh Kandjani A. , Vaezi Mohammad Reza , Shokuhfar Ali , Farzalipour Tabriz M.
Published: March 2009

ZnO nanoparticles because of their interesting properties and various
morphologies, has become one of the most attractive nanomaterials for research objectives. Its
significant properties has made it applicable in UV-Light emitters, varistors, transparent high
power electronics, gas sensors, etc., [1]. Many approaches have been used to obtain ZnO
nanoparticles, including: Hydrothermal [2], Solvothermal [3], Reverse micelles [4], Sol-Gel
[4], Sonochemical [5], and Chemical Bath Deposition [6], etc. Among these, hydrothermal
and alcohol-thermal methods have been extremely investigated. In this paper, buthanol as a
solvent is used for synthesis of Zinc oxide at 130°C and 150°C at different reaction periods.
Also the effects of different surfactants including: N_Cetyl_N,N,N,_trimethyl ammonium
bromide (CTAB), Poly vinyl pyrolidon-K90 (PVP), Poly ethylene glycol-15000 (PEG) on
obtained morphologies were investigated extremely. X-ray Diffraction (XRD) and Scanning
Electron Microscopy (SEM) were used for characterization of nanoparticles.
An Investigation on the Mechanism of TiC+Al2O3 Combustion Synthesis via Mechanical Activation of Double Phases in TiO2-Al-C System
Authors: Nayeri Sayed Hamid Reza Fatemi , Khaki Jalil Vahdati , Aboutalebi Mohammad Reza
Published: March 2009

The starting reaction in the combustion synthesis process in TiO2-Al-C system leading to
TiC+Al2O3 composite was evaluated using a combination of Differential Thermal Analysis (DTA),
X-Ray Diffraction (XRD) and Transmission Electron Microscope (TEM). Double phases in 3TiO2-
4Al-3C system were milled separately and then the third phase was added according to the
stoichiometric reaction for 3TiC+2Al2O3 composite formation. The combustion synthesis
temperature was observed to decrease from 962 °C to 649 °C after mechanical activation of TiO2/Al
mixture for 16 hr. On the contrary, the mechanical activation of Al/C and TiO2/C mixtures for 16 hr
made the reaction temperature increase to 995 °C and 1024 °C, respectively. TEM and XRD
patterns of as-milled powders showed that the reaction temperature changes could be due to
increased TiO2 and Al interface area. In addition, DTA experiments showed that for the sample in
which TiO2 and Al were mechanically activated the reaction occurred at the temperature even lower
than the aluminum melting point.
Nitrogen Diffusion in the Nb-2.0wt%Ti Measured by Mechanical Spectroscopy
Authors: Grandini Carlos Roberto , Monteiro da Silva Luciano , de Almeida Luciano Henrique , Florêncio Odila , Sandim Hugo Ricardo Zschommler
Published: March 2009

Metals that present bcc crystalline structure, when receiving addition of interstitial atoms
as oxygen, nitrogen, hydrogen and carbon, undergo significant changes in their physical properties,
being able to dissolve great amounts of those interstitial elements, thus forming solid solutions.
Niobium and most of its alloys possess bcc crystalline structure and, as Brazil is the largest world
exporter of this metal, it is fundamental to understand the interaction mechanisms between
interstitial elements and niobium or its alloys. In this paper, mechanical spectroscopy (internal
friction) measurements were performed in Nb-2.0wt%Ti alloys containing nitrogen in solid
solution. The experimental results presented complex internal friction spectra and with the addition
of substitutional solute, it was observed interactions between the two types of solutes (substitutional
and interstitial), considering that the random distribution of the interstitial atoms was affected by the
presence of substitutional atoms. Interstitial diffusion coefficients, pre-exponential factors and
activation energies were calculated for nitrogen in the Nb-2.0wt%Ti alloys.
Thermodynamical Behaviour of PdSe2 while Subjected Isothermally to High Pressure - Axial Level Analysis
Authors: Grigorova Veneta
Published: March 2009

We study thermodynamically the behaviour of PdSe2 while subjected to high pressure
under isothermal conditions. The present paper continues the study started in [1]. Here we present
the results of the axial calculations and analyses. Specific lengths, linear adjusted Gibbs free energy
changes and linear adjusted entropy generations were studied along each spatial axis separately. We
found that the first-order transition from PdS2 structure type to pyrite one at 20oC is accompanied by
saltatory contraction of a and b specific lengths and respective saltatory expansion of c specific
length. Under 300oC all specific lengths contract saltatory. In the transition point under 20oC PdSe2
gains saltatory stability along a and b axis and looses along c one, respectively. Besides, the loose
along c axis is bigger than the gains along a and b ones. Under 300oC the transition is accompanied
by slight gain of stability along all three spatial axes. Plateaux duration affects the stability of PdSe2
strongly under higher temperature.
Measurement of Aluminium Oxide-Film Thickness: Barrier Oxide Film and Oxide Porous Layer
Authors: Habib Khaled , Al-Muhanna K. , Al-Sabti F. , Al-Arbeed A.
Published: March 2009

In the present investigation, holographic interferometry was utilized for the first time to
measure in situ the thickness of the oxide film, alternating current (A.C.) impedance, and double
layer capacitance of aluminium samples during anodization processes in aqueous solution without
any physical contact. The anodization process (oxidation) of the aluminium samples was carried out
by the electrochemical impedance spectroscopy (EIS), in different concentrations of sulphuric acid
(0.5-2.5 % H2SO4) at room temperature. In the mean time, the real-time holographic interferometric
was used to measure the thickness of anodized (oxide) film of the aluminium samples in aqueous
solutions. Also, mathematical models were applied to measure the alternating current (A.C.)
impedance, and double layer capacitance of aluminium samples by holographic interferometry,
during anodization processes in aqueous solution. Consequently, holographic interferometric is
found very useful for surface finish industries especially for monitoring the early stage of
anodization processes of metals, in which the thickness of the anodized film, the A.C. impedance,
and the double layer capacitance of the aluminium samples in sulphuric acid (0.5-2.5 % H2SO4) can
be determined in situ. Futhermore, a comparison was made between the electrochemical values
obtained from the holographic interferometry measurements and from measurements of
electrochemical impedance spectroscopy(EIS) on aluminium samples in sulphuric acid (0.5-2.5 %
H2SO4). The comparison indicates that there is good agreement between the obtained
electrochemical data from both techniques. However, there is a drastic difference between the
measurement of the oxide film thickness by both techniques. The oxide film thickness of the
aluminium samples in 0, 0.5, 1.0, 1.5, 2.0, 2.5% H2SO4 by the optical interferometry is in a
micrometer scale. However, the oxide film thickness of the aluminium samples in 0, 0.5, 1.0, 1.5,
2.0, 2.5% H2SO4 by the E.I.Spectroscopy in a nanometer scale. This can be explained due to the fact
that the E.I.Spectroscopy is useful technique to measure the electrochemical parameters and the
thickness of the barrier (compact) oxide films. In contrast, the optical interferometry is found useful
technique to characterize and measure the thickness of the porous oxide layer. Also, the optimum
thickness of the oxide barrier film was detected to be equivalent to 0.612nm in sulphuric acid
concentration of 2.5% H2SO4 by E.I. spectroscopy.
Application of Artificial Neural Network for Prediction of Heat Treated Sintered Steels Properties
Authors: Khorsand H. , Arjomandi M. , Abdoos H. , Sadati S.H.
Published: March 2009

Heat treatment is an important method for improving the mechanical properties of
industrial parts that are made through the powder metallurgy. Most PM steels are subjected to
hardening and tempering, and it is due to this treatment that tempered martensite is formed. After
heat treatment, these steel’s mechanical properties are affected by the heat treatment parameters and
the initial density. In this paper, in order to make an evaluation of the effect of the above
parameters, FN-0205 PM steel with various densities is heat treated in different austenite conditions
and tempering time. Their mechanical properties are then evaluated and recorded. Afterwards, this
data obtained by experimental procedure are predicted for various conditions. The method
employed here is the well-known feedforward Artificial Neural Network (ANN) with the Back
Propagation (BP) learning algorithm. Comparison between predicted values and experimental data,
in the present study, indicate that the predicted results from this model are in good agreement with
the experimental values.
Austenite Formation Temperature Prediction in Steels Using an Artificial Neural Network
Authors: Arjomandi M. , Sadati S.H. , Khorsand H. , Abdoos H.
Published: March 2009

Determination of the temperature at which Austenite is formed is one of the important
parameters in the heat treatment process. Chemical composition is an effective factor on these
temperatures, particularly in steels that are used in various industries. In this research we have made
an attempt to determine these temperatures based on the chemical composition of the steel. The
technique used for this purpose is feedforward Artificial Neural Network (ANN) with the Back
Propagation (BP) learning algorithm. A comparison is made between Ac1, Ac3 temperatures
predicted with this model and those from the empirical equation as well as the experimental values
obtained from costly and time-consuming tests in scientific and industrial centers for various steels.
This comparison indicates that at Ac1, a better agreement exists between the ANN-predicted results
and experimental values than the results from the empirical equation and experimental values. At
Ac3, the results from the empirical equation are closer to those of the experimental than those
predicted from the ANN. This was due to the dispersion of the data set used.
Sonochemical Synthesis of SnO/ZnO Nano-Composite: The Effects of Temperature and Sonication Power
Authors: Arefian N.A. , Shokuhfar Ali , Vaezi Mohammad Reza , Esmaielzadeh Kandjani A. , Farzalipour Tabriz M.
Published: March 2009

Nanometer oxides e.g. SnO2, ZnO, TiO2, ZrO2, etc. have photocatalytic and gas
sensing properties which can be different in nanometer range. They have been produced by
several methods such as Chemical Bath Deposition (CBD), Pulsed-laser deposition, Chemical
Vapor Deposition (CVD), screen printing and firing process, spray pyrolysis technique,
magnetron sputtering, mechanical alloying, etc. It was found that the production method and
its parameters would affect the size and morphology of these oxides. By using a composite of
these oxides their properties would also be affected.
In this paper the effects of sonication and reaction temperatures on SnO/ZnO coupled oxides'
morphologies were investigated. These coupled oxides were characterized by X-Ray
Diffraction (XRD), X-Ray Florescence (XRF), Scanning Electron Microscopy (SEM), and
Differential Thermal Analysis (DTA).
As a result of using the ultra sound source, the sizes of nano oxides decreased, which is one of
the most important advantages of sonochemical synthesis in comparison with chemical bath
deposition synthesis of these nano-composites.
Effect of Thermal Gradient on Solidification Microstructure in the Ni-Base Single Crystal Superalloy CMSX10
Authors: Kim S.H. , Kim J.M. , Lee H.J. , Son S.D. , Lee J.H. , Seo Seong Moon , Jo Chang Yong
Published: March 2009

A single crystal superalloy including 6 wt.% Re, CMSX10 was studied by directional
solidification at various thermal gradients, 13 ~ 23oC/mm and solidification rates, 1~100 μm/s. A
high thermal gradient could be obtained by applying the liquid metal, such as Ga-In, as a cooling
media in directional solidification apparatus, and also by adjusting the cold chamber in the Bridgman
system. As increasing the solidification rate, the planar interface changed to cellular and dendritic
interfaces. The higher thermal gradient contributed to reducing the dendrite arm spacing effectively,
which results in reducing the size of eutectic, as well as higher solidification rate. The length of the
mushy zone decreased with increasing the thermal gradient and increased with increasing the
solidification rate.
Long-Range Diffusion of Hydrogen in Solid-Solution PdCe Alloys as Deduced from Absorption Experiments
Authors: Mazzolai Giovanni
Published: March 2009

The diffusion of H and the thermal decomposition of hydrides have been investigated at
high temperatures in two PdCe alloys of composition 5% and 9% Ce. It has been found that the H
diffusion coefficient obeys an Arrhenius-type of law with the following values of the activation
energy W and diffusion constant D0,
( ) 



= ± ×
= ±
−
s
m
D
W eV
2
7
0 2 2 10
0.20 0.02
(Pd95Ce5 alloy)
( ) 



= ± ×
= ±
−
s
m
D
W eV
2
7
0 2 1 10
0.24 0.01
(Pd91Ce9 alloy)
The high-temperature absorption data match the low-temperature ones deduced from internal
friction measurements, indicating that Ce atoms do not act as strong trapping centres for H. Thermal
decomposition of hydrides in the Pd95Ce5H0.008 alloy occurs in a single stage showing a
homogeneous solid solution state of the H-Me system.
Evaluation of Transmission Conditions for Thin Reactive Heat-Conducting Interphases
Authors: Mishuris Gennady , Miszuris Wiktoria , Öchsner Andreas
Published: March 2009

Imperfect transmission conditions modelling a thin reactive intermediate layer be-
tween two bonded materials in a dissimilar strip are derived in this paper. The interphase
material is assumed to be heat-resistant and situated in a thin rectangular domain between
the main materials. Different types of the interphase are investigated in detail: constant and
temperature dependent sources.
Numerical Study of the Inlet Conditions Influence on Laminar Plane Wall Jets
Authors: Mokni Amèni , Kechiche Jamel , Mhiri Hatem , Le Palec Georges , Bournot Philippe
Published: March 2009

In this paper, we present a numerical investigation of a laminar isothermal plane two
dimensional wall jets. Special attention has been paid to the effect of the inlet conditions at the
nozzle exit on the flow thermal characteristics in forced convection regime. Two velocities profiles
at the nozzle exit are used: uniform profile and parabolic profile. The system of equations
governing the studied configuration is solved with a finite difference scheme and an implicit
scheme, for numerical stability we use a staggered non uniform grid. The obtained results show,
first, that the inlet conditions affect the flow in the immediate neighbourhood of the nozzle (core
region) in which the flow is governed mainly by the inertias forces. At the established region the
results become independent of the flow inlet conditions.
Visualization of the Vacancy-Wind Effect Occurring in Chemical Diffusion and Ionic Conductivity in Solids
Authors: Belova Irina V. , Murch Graeme E.
Published: March 2009

Net fluxes of vacancies commonly occur during chemical interdiffusion in alloys, ionic
conductivity and the annealing out of radiation damage. When atoms with different jump rates
diffuse in a net flux of vacancies the phenomenon of the vacancy-wind effect will occur. This
effect, first discovered by the late Dr John Manning, is a subtle phenomenon arising from a
disturbed distribution of vacancies with respect to a given moving atom or species of atom. In this
paper, the vacancy-wind effect is discussed and its visualization, performed for the first time by
computer simulation, is demonstrated.
Mössbauer Spectroscopy Studies of Grain Boundaries in Nanostructured Metals
Authors: Popov Vladimir V.
Published: March 2009

The results of NGR studies of grain boundaries in nanocrystalline metals are briefly
reviewed and analyzed together with the data of ordinary diffusion experiments. Grain boundaries
in materials obtained both by powder technologies and severe plastic deformation (SPD) are
considered. Possible factors causing accelerated mass transfer in every case are analyzed with the
account taken of specific features of the structure of these materials.
Nanoparticle Friction Force and Effective Viscosity of Nanosuspensions
Authors: Rudyak Valery , Belkin A.A. , Tomilina E.A. , Egorov V.V.
Published: March 2009

The transport properties of nanofluids are investigated by the molecular dynamics
method. It is shown that the force acting on a nanoparticle is nonstationary, in contrast to the Stokes
force. In the initial stage of relaxation, the friction force is greater than the Stokes value. Subsequently,
this force decreases and reaches an asymptotic value. This value is comparable to the
Stokes force only for a massive particle. A correlation for determining the friction coefficient is
constructed. It is established that the effective viscosity coefficient of nanofluids depends not only
on the volume concentration of nanoparticles but also on the nanoparticle mass and radius.
Microstructure Evaluation of Solid-Solution in Fe-Cu Immiscible Alloy System
Authors: Ghassemi S.H. Mir Shah , Shokuhfar Ali , Vaezi Mohammad Reza
Published: March 2009

The study of mechanical alloying on the Fe–Cu system, as a model system for those with
positive heats of mixing, are investigated. In this research work the effects of impact force, such as
increasing in the surface temperature of powders, the number of vacancies and pipe diffusion, on
the strain and grain size of final powders have been studied. The aim of this research is to find the
optimum condition for mechanical alloying of Cu-Fe system by the help of automatic design and
analysis of TAGUCHI experiments.
Evolution of the Enriched Layer at the Oxide/Metal Interface during Oxidation of Recycled Steels with Copper and Copper+Nickel Residuals
Authors: Webler B.A. , Sridhar S.
Published: March 2009

The presence of the residual element copper in recycled steels causes a surface cracking
phenomenon during thermo-mechanical processing which is known as “hot shortness”. The cracks
result from a copper-rich liquid that forms at the oxide/metal interface and subsequently embrittles
austenite grain boundaries. Minimizing formation of the liquid phase would reduce or eliminate
cracking. Thus, the evolution of the liquid layer is an important consideration when designing an
optimal thermomechanical processing cycle in scrap-based steel plants. The time evolution of the
liquid phase is dependent on the competing processes of enrichment rate due to iron oxidation and
the rate of copper back-diffusion into the steel. This paper presents a fixed grid finite difference
model that predicts the evolution of the enriched region as a result of a given oxidation kinetics and
solution of Fick’s 2nd law. The model predictions are in agreement with measured data for the case
of an iron alloy containing 0.3 wt% copper oxidized in air at 1150°C. Model predictions indicate
that initial copper content, oxidation kinetics, and alloy microstructure (i.e. grain boundary
diffusion) have the most significant influence on the copper-rich layer whereas the solubility
increase due to nickel additions was not found to have an appreciable influence.