bluuebunny/crossref_metadata_2025 huggingface dataset:
Experiments Proving the Mixed Control of the Reactive Diffusion System Zn/Fe3Si with Clamp Press
Authors: Chen Y.C. , Cui Hongzhi , Ding J. , Chen Yun Bo
Published: March 2009

More than twenty years were needed for people to understand the formation mechanism
of the periodic-layered structures not only because of the complications of pattern formation, but
also due to the limits of traditional diffusion theories. Based on the general theory of interdiffusion
growth proposed by Y.C. Chen et al. [1], the quantitative model of periodic layer formation during
solid state reactions has been succeeded [2]. The experimental results shown in this paper proved
one of the model’s predicts that the reactive diffusion system Zn/Fe3Si with clamp press annealed at
663K should be mixed controlled. Also, the important influence of the uniaxial compressive stress
on the diffusion coefficient was emphasized and the reasons are discussed.
Mass Transfer Modelling in an Acoustic-Assisted Osmotic Process
Authors: Simal Susana , Cárcel J.A. , Bon J. , Castell-Palou Á. , Rosselló Carmen
Published: March 2009

Ultrasounds are mechanical waves that produce different effects when travelling through
a medium, some related to mass transfer (i.e. microstirring at the interface, the so called "sponge
effect" and cavitations). Thus, ultrasound appears to be a way to reduce both the internal and
external resistances in osmotic food drying processes. In this study, the influence of the ultrasounds
on water and solute transports during osmotic processes of drying is evaluated. Two different
systems have been studied, apple slabs immersed in 30ºBrix sucrose solution, and pork loin slabs in
sodium chloride saturated brine. The mathematical modelling of the mass transfers has been carried
out by assuming diffusional mechanism and considering the mutual effect between the two mass
transfers, the water losses and solute gains. The mass transfer curves in the osmotic process of apple
drying in sucrose solution were satisfactorily simulated by using a diffusional model considering
independent mass fluxes. Nevertheless, this model did not allow for the accurate simulation of the
water losses in the system constituted by pork-loin in saline solution. When the mass fluxes were
considered mutually affected, the simulation was accurate for both cases water and solute transfer.
On the Role of Diffusion in the Oxidation of Fe, Ni, Co and the Fe-Sn Alloy by Calcium and Sodium Sulfates
Authors: Chumarev V.M. , Maryevich V.P. , Shashmurin V.A.
Published: March 2009

Diffusion processes play a dominant part in the macro kinetics of Fe, Ni and Co
oxidation by calcium and sodium sulfates. Here, the reaction product forms a compact covering
which spatially divides the reagents on the surface in the same way as in the oxidation and
sulfidization of metals by oxygen and sulfur. Therefore, it is possible to assume in advance that
interaction of metals with calcium and sodium sulfates will be determined not by the actual
chemical reaction properly but by the diffusion transport processes.
Diffusion and Stress in Tungsten; Different Time Scales
Authors: Danielewski Marek , Wierzba Bartłomiej
Published: March 2009

The Darken method is used to evaluate and compare different time scales in an ideal
crystal lattice. The crystalline tungsten exemplifies presented approach. It is shown that in this
metal and at 1273 K the time scales differ by nine orders of magnitude. Particular emphasis is given
to the problem of deformation, the temperature and the mass diffusion time scales in tungsten quasicontinuum.
The transport process in the nonuniform temperature and stress field is characterized by
representative velocities. These velocities allow to quantify the time and length scales and can be
used for the proper non-dimensialization and effective solution of the particular transport problems.
Measurement of Diffusion Coefficients in Building Materials Using the Initial Rate of Sorption
Authors: Delgado João M.P.Q.
Published: March 2009

This work presents experimental values of molecular diffusion coefficient, obtained with
samples of building materials, using a non-stationary process of moisture absorption. The
experiments covered four different types of building materials (with two selected ranges of relative
humidity) and were carried out in the range of temperatures between 20°C and 40°C.
The results show that the increase in temperature resulted in an increase in molecular diffusion
coefficient and the relative humidity also influenced the molecular diffusion in a uniform manner.
Finally, a good agreement with literature values was found.
The Role of Reducibility in Achievement of the Minimal Coke Consumption in the Blast Furnace Smelting
Authors: Dmitriev Andrey N.
Published: March 2009

The limit of perfection of a blast-furnace smelting, including in its concept a
minimal theoretically possible coke consumption, is determined by a thermodynamic equilibrium of
oxidation-reduction reactions in separate zones of a furnace.
It is possible to determine minimum coke consumption, for example, with the use of the
mathematical model suggested by us. The following prerequisites underlie the mathematical model.
Heat exchange in a blast furnace was completed, i.e. there is a small thermal gradient between gas
and charge on a certain height. In a certain zone of the furnace at a reduction stage of magnetite the
reaction of wustite reduction tends to a thermodynamic equilibrium. In this zone so-called zonal
reduction realizes when the processes of reduction of various iron oxides combine in time. The
significant role belongs here to diffusion of gas in pores of iron ore material.
The solution of equations set for the bottom zone presented by a condition of a
thermodynamic equilibrium, namely, the equilibrium constant of wustite reduction by carbon oxide,
material and thermal balances, supplemented by the equation of the heat balance for the top zone,
allows calculating the main indices of blast furnace smelting. Indices thus calculated are extremely
accessible (minimum) at the given parameters of charge and blast.
In the paper quantitative values of the coke consumption were presented at stage and zonal
reduction of iron oxides.
Defect Analysis in Semiconductor Materials Based on p-n Junction Diode Characteristics
Authors: Simoen Eddy , Claeys Cor , Vanhellemont Jan
Published: March 2009

This paper aims at reviewing the possibilities of using p-n junction diodes for lifetime and defect analysis in semiconductor materials. In a first part, the theoretical basis of lifetime extraction based on p-n junction current-voltage and capacitance-voltage characteristics will be discussed. In the next parts, these methods will be applied to different cases relevant for advanced semiconductor materials and device processing. First, the impact of the initial interstitial oxygen content and thermal pre-treatment of Czochralski silicon substrates on the carrier generation and recombination lifetime is discussed. A comparison will also be made with epitaxial and Float-Zone silicon. In a next part, the impact of proton-irradiation damage on the diode behavior will be presented. In the final part, the application of the technique on SiGe and Ge based p-n junctions is described. Whenever possible and useful, the information extracted from p-n junction characteristics will be compared with direct lifetime measurements using microwave techniques. Additional defect information has also been gained from other well-known techniques like Deep- Level Transient Spectroscopy (DLTS), Electron-Beam-Induced Current (EBIC), etc and will be correlated with the p-n junction results. The review is wrapped up in a summary followed by an outlook on future evolution and requirements.
Monte Carlo Modelling of the Effective Diffusivity in Composite Material
Authors: Belova Irina V. , Murch Graeme E.
Published: March 2009

In this paper we perform a systematic Monte Carlo study of the effective diffusivity in a
2D composite in which the dispersed phase (squares) is arranged in square planar and brick-work
patterns within the matrix phase. We focus on the commonly encountered case where the dispersed
phase has a much lower diffusivity than the matrix and where the segregation of the diffusant
favours the matrix phase. It is found that while the generalized Maxwell-Garnett Equation generally
describes the effective diffusivity semi-quantitatively, in order to have an accurate representation of
the effective diffusivity at moderate volume fractions of the dispersed phase, it is necessary to use a
more refined Maxwell-Garnett Equation that takes into account the actual shape and geometry of
the dispersed phase.
Surface Microrelief Transformation Induced by Laser during Thin Al Film Growth on the (001) GaAs by the CBE Method
Authors: Lioubtchenko Dmitri V. , Briantseva Tatiana A. , Markov I.A. , Bullough Tim J.
Published: March 2009

In this work microrelief transformation of the (001) GaAs surface due to thin Al film deposition by means of the CBE method has been observed. The growth process was monitored insitu using laser reflectometry. Investigations of samples formed, carried out using TEM-microscopy, show that one of the basic causes of the microrelief transformation is the laser assistance of metal growth. A laser with a low power is used in this work for Al layer composite control in CBE. It was found that, in spite of using a laser having a low power, it is possible to stimulate and guide the complex physical and chemical reactions between deposited Al atoms and the GaAs near-surface layer. It has been found that metal film growth with laser assistance is a non-equilibrium process. The shapes and dimensions of the grown islands depend upon the laser power.
Investigations of the axial displacements of Co2+and Ni3+ in Al2O3
Authors: Wu Shao Yi , Fu Qiang , Lu Guang Duo , Yao Jin Song
Published: March 2009

The axial displacements for Co2+ and Ni3+ in Al2O3 are theoretically investigated starting from the perturbation formulas of the EPR parameters for a 3d7 ion with high spin (S=3/2) and low spin (S=1/2) in trigonal symmetry, respectively. Based upon these studies, the Co2+ is found to shift towards the center of the oxygen octahedron by an amount ZCo (≈ 0.03 Å) along the C3 axis, while the Ni3+ may suffer another axial displacement ZNi (≈ −0.38 Å) away from the center of the octahedron. The calculated EPR parameters based upon the above axial displacements show good agreement with the observed values. The differences in the EPR parameters and the axial displacements for the two 3d7 ions are discussed.
Interdiffusion Data in Multicomponent Alloys as a Source of Quantitative Fundamental Diffusion Information
Authors: Belova Irina V. , Murch Graeme E.
Published: March 2009

Tracer diffusion experiments have historically furnished much of the information about
fundamental diffusion processes as embodied in such quantities as tracer correlation factors and
vacancy-atom exchange frequencies. As tracer diffusion experiments using radiotracers are rather
less often performed nowadays, it is important to be able to process other diffusion data to provide
similar fundamental information. New procedures that are primarily based around the random alloy
model have been established recently for analyzing chemical diffusion data in binary and ternary
alloy systems. These procedures are reviewed here. First, we review the random alloy model, the
Sum-rule relating the phenomenological coefficients and three diffusion kinetics formalisms
making use of the random alloy. Next, we show how atom-vacancy exchange frequency ratios and
then component tracer correlation factors can be extracted from chemical diffusion data in alloy
systems. Examples are taken from intrinsic diffusion and interdiffusion data in a number of binary
and ternary alloys.
Steam Oxidation Behaviour of Ni-Based Single Crystalline Superalloy for the Advanced Gas Turbine
Authors: Fujikawa Hisao , Murakumo Takao , Newcomb Simon , Harada Hiroshi
Published: March 2009

Steam oxidation behavior of a new Ni-based single crystalline superalloy (TMS-75)
developed as the high strength material for the advanced gas turbine which would be cooled by
steam was studied in comparison with Inconel 625 alloy which is a representative Ni based
superalloy and 12Cr ferritic steel which is conventionally used in boiler tubes and main steam pipes
and steam turbines. TMS-75 alloy showed worse oxidation resistance in steam than Inconel 625
alloy, but it had much better oxidation resistance in steam than 12Cr steel. Also, the oxide scale of
Inconel 625 alloy is very thin and is mainly composed of Cr2O3. However, the outer scale of TMS-
75 alloy was mainly composed of NiO with Co and a little Al and other elements. The Ni/Co ratio
in the oxide scale was a little higher in the outer layer than in the inner layer.
The Effect of Oxide Cracks on Hydrogen Ingress in ZrO2
Authors: Li Hua Long , Wen Q. , Szpunar Jerzy A.
Published: March 2009

The oxide film, which is formed on the Zr-2.5% Nb pressure tube surface serves as a
protective barrier against hydrogen ingress. Hydrogen ingress is a diffusion process and therefore is
affected by the distributions of oxide orientation, grain size, shape, and boundary. Our previous
research has focused on understanding the oxidation mechanism and predicting the hydrogen
ingress and oxidation kinetics. In this paper, a simple model has been established to simulate the
effects of cracks/voids on diffusion process. This model can be potentially used to study the
influences of oxide cracks on hydrogen permeation. The effects of the volume fractions, orientation
and distributions of cracks on the steady state diffusion flux are simulated.
The BFS Method Combined with Chemical Cluster Interactions for the Study of Order-Disorder Transitions
Authors: Schurmans Maarten , Luyten Jan , Creemers Claude
Published: March 2009

First Principles (FP) methods are invoked to improve the accuracy of Bozzolo-Ferrante-
Smith (BFS) model, one of the quantum-approximate modeling techniques for the computation of
thermodynamic properties that involve a large number of particles. The BFS method calculates the
energy of an atom in an alloy in two steps [1]. A first term pertains to the structural contribution. A
recent improvement [2] allows to calculate the strain energy depending on the local environment
[1,2] and this involves only pure element properties of the different atomic species. In the second
step, binary chemical interactions are taken into account. This was originally done by only two
interaction parameters for each atom pair in an alloy. In contrast, the adaptable parameterization of
Cluster Expansion Methods (CEM) routinely incorporates any number of FP data to describe
ordering in alloy systems. But in standard CEM calculations, no explicit information on local
atomic displacements is used. In this work, the BFS chemical energy term is successfully replaced
by a CEM chemical term to combine the ability of BFS to account for local displacements and the
ability of CEM to include as many FP results as needed for the correct evaluation of alloying
effects.
Thermodynamic Aspects of Diffusion Paths in Ternary Systems
Authors: Laas Tony , Ugaste Ü. , Priimets J.
Published: March 2009

Description of diffusion paths is one of the most interesting and topical problems in
experimental investigations of interdiffusion in multicomponent systems and, particularly, in
ternary systems. The relationship between effective interdiffusion coefficients and diffusion paths in
ternary systems has been discussed earlier but the specific influence of the mobility and
thermodynamic properties of components on the characteristics of the diffusion path is still unclear.
In this paper an attempt is made to clarify the separate influences of mobility and thermodynamics
on the behavior of diffusion paths in ternary systems and the corresponding correlation is found. It
is shown that in most cases the deviation of the diffusion path from linearity (an ideal system) is
related to the deviation of the thermodynamic properties from the ideal. The results obtained are
analyzed on the basis of thermodynamic data for the ternary system Cu-Fe-Ni.
Tracer Diffusion of Molybdenum in Crystallized Fe79-yMo8Cu1B12+y Alloy
Authors: Čermák Jiří , Stloukal Ivo
Published: March 2009

99Mo tracer diffusion in Fe79-yMo8Cu1B12+y (y = 0, 3, 5) alloys was studied using serial
sectioning method in the temperature range 573 – 773 K. Sputtering by Ar+ ions was applied as a
sectioning technique. The measurement was carried out with the ribbon-like samples prepared by
planar flow casting technique and crystallized before the diffusion experiment by a thermal shock in
vacuum. The structure was formed by areas of three distinct types differing in chemical
composition r = at. % Mo / at. % Fe: (i) r = 0.02 (crystallites of Fe, mean size d ~ 150 nm), (ii) r =
0.09 (relaxed phase; d ~ 150 nm) and (iii) r = 0.83 (boride phase; d ~ 30 nm). The measured
profiles were linear in co-ordinates ln cMo vs. x1.5 (cMo – concentration of Mo in depth x), indicating
that the diffusion of 99Mo was controlled by „type A-B” kinetics.
From Phase Equilibria to Transformation Dynamics
Authors: Mohri Tetsuo , Ohno Munekazu , Chen Ying
Published: March 2009

First principles calculations have been applied in various fields in Materials Science. The
authors have been attempting to reproduce a binary phase diagram by combining FLAPW
electronic structure total energy calculations with Cluster Variation Method of statistical mechanics.
Such a first principles calculation for static equilibrium has been quite successful for a series of Febased
alloy systems. Recently, main attention is directed towards the extension of the first
principles calculation to phase transformation dynamics by incorporating Phase Field Method. A
series of preliminary calculations on disorder-L10
ordering in Fe-Pd and –Pt are satisfactory and the
evolution process of Anti-Phase Boundaries was reproduced. In the present report, first-principles
calculations of phase equilibria and phase transformation are briefly reviewed. Particular focuses
are placed on coarse graining operation which authors developed and and time scaling as a
remaining problem.
Carbon and Nitrogen Activities of Materials of Weld Joints
Authors: Hodis Z. , Sopoušek Jiří
Published: March 2009

The demand for higher efficiency of energy production in fossil-fired power stations
needs the increase of working temperatures up to 625 °C. This limitation is given by creep
properties of the materials used for steam turbines and the other parts under long high-temperature
exploitation. The most widely used materials for this application remain steels. From
thermodynamic points of view, the steels can be thermodynamically treated as Fe-Me-N-C based
closed systems. Phase diagrams and temperature dependent carbon and nitrogen activities of the
steels can be calculated using CALPHAD approach, which is based on semiempirical
thermodynamic model of the multicomponent/multiphase system and integral thermodynamic
condition of phase equilibrium. The activities of all elements can be obtained mathematically. In
this contribution, the CALPHAD method is applied on an investigation of the heterogeneous welds,
for bainitic and martensitic base materials and for electrodes and filler weld alloys. Calculated
temperature dependences of carbon and nitrogen activity are very important for a design of
dissimilar weld joints. This information is essential, for example, for life-time estimations of the
heterogeneous welds under high temperature creep.
Study of Reaction Diffusivity in the Copper–Indium–Tin Ternary System
Authors: Drápala Jaromír , Kubíček Petr , Vřeštál J. , Losertová Monika
Published: March 2009

Interaction of lead-free solders with copper substrate represents an important
phenomenon in the issue of reliability of solder joints. New experimental data describing phase
equilibria in the Cu-In-Sn system after long-time diffusion annealing at the 400 °C/50 hours, 600
°C/310 hours and 600 °C/48 hours will be presented. The composition of solders was: 100 % Sn, 75
% Sn + 25 % In, 50 % Sn + 50 % In, 25 % Sn + 75 % In, 100 % In. The fast quenching method was
employed to freeze thermodynamic equilibrium after annealing, followed by metallography, microhardness
measurements, SEM (Scanning Electron Microscope) and WDX (Wave Dispersive X-ray)
analysis. New phase equilibrium data, together with the data from literature, represent the best
existing experimental description of phase equilibria in the system in question. The obtained
experimental results of the phase equilibria were compared with the thermodynamic modelling by
the CALPHAD (Calculation of Phase Diagrams) method and with other authors.
Atomic Migration in Bulk and Thin Film L10 Alloys: Experiments and Molecular Dynamics Simulations
Authors: Pierron-Bohnes Veronique , Montsouka R.V.P. , Goyhenex Christine , Mehaddene T. , Messad Leila , Bouzar H. , Numakura Hiroshi , Tanaka Katsushi , Hennion B.
Published: March 2009

Ferromagnetic L10 ordered alloys are extensively studied nowadays as good candidates
for high density magnetic storage media due to their high magnetic anisotropy, related to their
chemical order anisotropy. Epitaxial thin bilayers NiPt/FePt/MgO(001) have been grown at 700 K
and annealed at 800 K and 900 K. At 800 K, the L10 long-range order increases without measurable
interdiffusion. At 900 K, the interdiffusion takes place without destroying the L10 long-range order.
This surprising observation can be explained by different diffusion mechanisms that are
energetically compared using molecular dynamics simulations in CoPt in the second moment tight
binding approximation. In addition, the frequencies of the normal modes of vibration have been
measured in FePd, CoPt and FePt single crystals using inelastic neutron scattering. The
measurements were performed in the L10 ordered structure at 300 K. From a Born-von Karman fit,
we have calculated the phonon densities of states. The migration energies in the 3 systems have
been estimated using the model developed by Schober et al. (1981). The phonon densities of states
have also been used to calculate several thermodynamic quantities as the vibration entropy and the
Debye temperature.
Self-Diffusion in Covalent Amorphous Solids – A Comparative Study Using Neutron Reflectometry and SIMS
Authors: Schmidt Harald , Gupta Mukul , Geckle Udo , Bruns Michael
Published: March 2009

The self-diffusion of nitrogen is studied in amorphous silicon nitride, which is a model
system for a covalently bound amorphous solid with a low atomic mobility where reliable diffusion
data are still lacking. Comparative experiments on Si14Nx/Si15Nx (x ≈ 1.33) isotope multilayers were
carried out with secondary ion mass spectrometry (SIMS) and neutron reflectometry (NR),
respectively. It was found that experiments with SIMS are not very well suited for the determination
of diffusivities in a broad temperature range. The minimum diffusion length of about 5-10 nm
detectable with this method is too large. At high temperatures (> 1200 °C) the amorphous solid
crystallizes before any diffusion is measured and at low temperatures (< 1100 °C) the diffusivities
are too low to be detected. In contrast, with neutron reflectometry diffusion lengths in the order of 1
nm and diffusivities down to 10-24 m2 s-1 were measured between 950 and 1250 °C. The potential of
this method for the determination of ultra slow diffusion processes is discussed.
Atomic Motion and Diffusion Mechanism of Hydrogen in Amorphous Ceramics of the System Si-B-C-N
Authors: Gruber Wolfgang , Borchardt Günter , Schmidt Harald
Published: March 2009

In this work we investigated the mobility of hydrogen in amorphous ceramics with the
composition Si13B13C60N13 (AM26C). The material was derived from a pre-ceramic polymer and
thermolyzed at 1000 °C. After thermolysis the AM26C ceramics are assumed to be separated in an
amorphous SiC phase and an amorphous C(BN)x phase. To measure the diffusivities we used
deuterium as a tracer, which was introduced via isotope exchange from the gas phase at
temperatures between 700 °C and 1100 °C. Depth profiling was done with secondary ion mass
spectrometry (SIMS). The profiles could be fitted with complementary error functions. The
diffusivities obey an Arrhenius law. The activation enthalpy is 0.8 eV, the pre-exponential factor is
5×10-12 m2 s-1. These values are close to those found for glassy carbon and thin amorphous C-B-N
films as reported in the literature. We therefore conclude that the amorphous C(BN)x phase is the
transport path for hydrogen in AM26C ceramics. A direct interstitial diffusion mechanism can
account for the activation enthalpy of 0.8 eV. The low value for the pre-exponential factor is
attributed to an entropy factor arising from the temperature dependence of the chemical potential of
hydrogen.
Effect of Fe Addition on Ordering Kinetics in Ni3Al1-xFex System. Monte Carlo Simulation
Authors: Partyka E. , Abdank-Kozubski Rafał Leszek
Published: March 2009

The influence of Fe admixture on ordering kinetics in Ni3Al1-xFex was studied by
running Monte Carlo simulations in a model system A3B1-xCx showing similarly to
Ni3Al1-xFex destabilization of the ordered phase when admixing a ternary element C. Detailed
analysis of atomic jump statistics revealed a dominance of the C-atom jumps in the
creation/elimination of antisite defects as well as in the migration of antisites within majority
sublattice. The results elucidate the role of Fe alloying in the kinetics of chemical ordering in
Ni3Al.
Nonequilibrium Vacancies in Nanosystems
Authors: Gusak Andriy , Kornienko Semen , Lutsenko G.V.
Published: March 2009

The influence of nonequilibrium vacancy distribution, generated by a difference of
intrinsic fluxes of components under limited efficiency of vacancy sinks/sources, on various
diffusion processes, is analyzed. Interdiffusion, reactive diffusion, reactive phase growth under
electric current, spinodal decomposition, collapse of compound nanoshells, ripening are considered.
Nonlinear Stress Effects in Diffusion
Authors: Beke Dezső L. , Erdélyi Z. , Katona G.L.
Published: March 2009

According to classical Nernst-Einstein equation the diffusive flux is proportional to the
driving force. However, this linear law is not valid if the driving force is very large. Attempts in the
literature for the derivation of an “improved relation” till now were mostly restricted to the cases
when the diffusion coefficient was independent of the composition. On the other hand, even if there
are no externaldriving forces (other than related to the chemical driving force) present, deviations
from the Fick I law are expected (transition from parabolic to linear growth-behaviour) on
nanoscale for composition dependent diffusion coefficients. General description for the case when
the driving forces and the diffusion asymmetry are large, is treated. The special case of large
pressure gradients is discussed in detail and their effects on the deviation form the parabolic growth
law on nanoscale will be analyzed. Effect of a pressure gradient on the crossover thickness between
parabolic and linear regimes and on the interface transfer coefficient, K, is also treated.
Stress Relaxation Mechanisms during Cd21Ni5 Intermetallic Growth under High Hydrostatic Pressure
Authors: Kaganovsky Yuri S. , Paritskaya Lyudmila N. , Bogdanov V.V. , Łojkowski Witold
Published: March 2009

Stress relaxation processes accompanying intermetallic growth during
reactive diffusion between Cd and Ni have been studied by the methods of optical and
scanning electron microscopy, provided with X-ray microanalysis. The experiments
were carried out with the two-layer Cd-Ni samples at 250 and 280oC under hydrostatic
pressures 350-900 MPa. The observed processes have been compared with those
occurred at low pressures to demonstrate that the mechanisms of stress relaxation and
thus the kinetics of intermetallic growth essentially depend on applied hydrostatic
pressure. New mechanisms of stress relaxation were found, such as Cd extrusion and Cd
whisker growth, which accompanied formation of Cd21Ni5 compound. It is shown, that
the whisker growth is more probable at lower temperatures when the grain size is
smaller, and the stress gradient, which support a driving force for whisker formation, is
higher. An atomic mechanism for whisker growth, based on diffusion climbing of
dislocation loops produced by Bardeen-Herring source for building new atomic layers,
has been discussed.
Solid-State Reactions in Ni(10 nm)/C(2 nm)/Si(001) Thin Film System
Authors: Makogon Yu.N. , Pavlova O.P. , Beddies G. , Mogilatenko A.V. , Chukhrai O.V.
Published: March 2009

Annealing environment effect on the phase formation in Ni(10 nm)/C(2 nm)/Si(001) thin
film system produced by sequential sputtering of C and Ni targets without vacuum breaking was
under investigation. The specimens were annealed 30 s in vacuum of 1.3·10-4 Pa and in nitrogen
flow in the temperature range of 450 - 1000°C. The temperature stimulated solid-state reactions that
occur as the result of interdiffusion processes between layers of the thin film system under
investigations were examined by X-ray - and electron diffractions, resistivity measurements and
Rutherford backscattering. It was established that an annealing environment has a strong impact on
the development of the solid-state reactions in Ni(10 nm)/C(2 nm)/Si(001) thin film system.
Dopant Diffusion during Amorphous Silicon Crystallization
Authors: Portavoce Alain , Simola Roberto , Mangelinck Dominique , Bernardini Jean , Fornara Pascal
Published: March 2009

We have investigated the redistribution of B during the crystallization of an amorphous
Si layer homogeneously doped with P. The redistribution of B only occurs for concentrations lower
than 2 × 1020 at cm−3. Crystallization leads to a non “Fickian” redistribution, allowing an abrupt
interface between the regions doped and undoped with B. Once the crystallization is ended, B
diffuses through the layer in the type B regime with a coefficient which is in agreement with the
literature data for diffusion in polycrystalline Si. Although the P distribution is homogeneous in the
entire layer, for a temperature as high as 755 °C, P diffuses towards the region the most
concentrated in B. The B and P interactions are interpreted as chemical interactions.
Grain Boundary Surface Tension, Segregation and Diffusion in Cu-Sn System
Authors: Gershman Evgeny I. , Zhevnenko Sergei
Published: March 2009

Grain boundary and free surface tension for pure copper and copper-tin alloys are
measured. On the base of these data isothermes of grain boundary tension, free surface tension and
isothermes of adsorption are constructed in assumption of a dilute solution. Grain boundary
diffusion coefficients of copper were calculated by using the relation of Borisov et. al. for copper
and copper-tin alloys.
The Stress Field in Cu-Fe-Ni Diffusion Couples
Authors: Wierzba Bartłomiej , Danielewski Marek , Bachorczyk Nagy Renata , Pietrzyk Maciej
Published: March 2009

We compare the experimental and computed results of the stress assisted interdiffusion.
The Cu-Fe-Ni diffusion couples were investigated at 1273 K. The alloys in this system do not form
ideal solid solutions and consequently the Calphad method was used to compute the elements
activities. The method applied in this work base on the Darken’s drift velocity concept, Vegard law
and Navier-Lamé equation. It allows computing the deformation field during the interdiffusion
process. The driving force for diffusion in such a ternary system is the gradient of the chemical
potential which can be calculated from the concentration profiles and using the known
thermodynamical data of the system. Comparison between the Darken method without stress and
the influence of stress on the interdiffusion in the Cu-Fe-Ni system is presented. Simulations that
take into account the deformation field give better fit to the experimental results. Moreover we
show qualitative and quantitative differences between the simulations of interdiffusion using the
Calphad method and with the ideality sweeping statement.
Nonlinear Field Theory of the Stress Induced Interdiffusion and Mass Transport
Authors: Dłużewski Paweł
Published: March 2009

Constitutive equations for interdiffusion and mass transport induced by the stress
gradient in crystal lattice is presented in terms of continuum thermodynamics. Only the stan-
dard balance laws are analysed for the mass, momentum, moment of momentum, energy and
entropy. In consequence the driving forces for interdiffusion of chemical constituents are deter-
mined. The forces depend not only on the stress gradient but also on the gradients of chemical
components and temperature. The driving forces are used next in constitutive modelling of
interdiffusion and mass transport in crystal lattice.
Effect of Mg Contents on Trapping Efficiency in Al-Mg System Using PAS
Authors: Kamel N.A.
Published: March 2009

PLT and the Doppler broadening S-parameter were used to characterize the Al-Mg alloys, AA5005, AA5051, AA5052 and AA5083. The trapping efficiencies of these alloys were estimated to be 2.42 x 109, 2.29 x 109, 2.24 x 109 and 2.27 x 109 s-1 cm3, respectively, and the corresponding trapping cross-sections were estimated to be 2.66 x 10-16, 2.14 x 10-16, 2.10 x 10-16 and 3.51 x 10-16 cm2. It was found to be very clear that the mean lifetime and S-parameter exhibited the same behaviour as a function of the degree of deformation, and that they saturated at the same degree of thickness reduction.
Growth Kinetics on Nanoscale: Finite Diffusion Permeability of Interfaces
Authors: Beke Dezső L. , Erdélyi Z.
Published: March 2009

Growth kinetic is either diffusion or interface reaction controlled process, characterized by parabolic or linear relationships, respectively. The well known diffusion paradox, predicting infinitely fast diffusion kinetics at short times (distances) for diffusion control will be discussed and resolved, by showing that the diffusion permeability across the interface should be finite at the very beginning of the process. Thus one can arrive at an atomistic interpretation of the interface transfer coefficient, K, and at linear growth kinetics even if there is no extra potential barrier present at the interface, usually assumed in the interpretation of interface reaction control. It is also shown that this phenomenon is a typical nanoeffect: after a certain diffusion distance (lying between 0.01 and 300 nm, depending on the composition dependence of the diffusion coefficient) the finite permeability of the interface will not restrict the growth and normal diffusion control will be observed.
Diffusion Mechanisms in Nanocrystalline and Nanolaminated Au-Cu
Authors: Jankowski Alan F.
Published: March 2009

Thermal anneal treatments are used to identify the temperature range of the two dominant diffusion mechanisms – bulk and grain boundary. To assess the transition between mechanisms, the low temperature range for bulk diffusion is established utilizing the decay of static concentration waves in composition-modulated nanolaminates. These multilayered structures are synthesized using vapor deposition methods as thermal evaporation and magnetron sputtering. However, at low temperature the kinetics of grain-boundary diffusion are much faster than bulk diffusion. The synthesis of Au-Cu alloys (0-20 wt.% Cu) with grain sizes as small as 5 nm is accomplished using pulsed electro-deposition. Since the nanocrystalline grain structure is thermally unstable, these structures are ideal for measuring the kinetics of grain boundary diffusion as measured by coarsening of grain size with low temperature anneal treatments. A transition in the dominant mechanism for grain growth from grain boundary to bulk diffusion is found with an increase in temperature. The activation energy for bulk diffusion is found to be 1.8 eV·atom-1 whereas that for grain growth at low temperatures is only 0.2 eV·atom-1. The temperature for transitioning from the dominant mechanism of grain boundary to bulk diffusion is found to be 57% of the alloy melt temperature and is dependent on composition.
Modelling of Oxygen Diffusion and Segregation at Interfaces in Ag-MgO Composites
Authors: Belova Irina V. , Öchsner Andreas , Muthubandara Nilindu , Murch Graeme E.
Published: March 2009

The presence of atomic oxygen at internal metal-ceramic oxide interfaces significantly affects the physical properties of the interfaces which in turn affects the bulk properties of the material. This problem is addressed for the model composite system Ag-MgO from a phenomenological point of view using a lattice-based Monte Carlo method and a finite element method extended with special user-subroutines. We simulate the time dependence of oxygen depth and contour profiles. We are able to show very good agreement between these two methods.
Concentration Micro-Field for Lamellar Eutectic Growth
Authors: Wołczyński Waldemar
Published: March 2009

A possibility of a modification of the Jackson-Hunt theory of an oriented structure
formation is analysed. A new model for the formation of a concentration field ahead of growing
regular lamellae with respect to the solid / liquid interface shape is presented. A coordinate system
applied in the model is attached to the solid / liquid interface to be advancing in the z - direction,
identically with interface moving at a constant velocity, v . The solution to a diffusion equation is
given for the improved formulation of the boundary conditions. The boundary conditions are related
to the interplay between the diffusion required for phase separation and the formation of the interphase
between both lamellae. The boundary conditions are formulated to establish the stability of
lamellar structure formation under steady-state conditions. It is assumed that stable growth of the
lamellae is ensured by the separation of concentration fields within a boundary layer ahead of the
solid / liquid interfaces of both the α and β " phases. Coupled lamellar growth with the presence of
a leading phase protrusion is defined. The general mass balance is analysed for a solute
concentration in the liquid, taking into account a planar solid / liquid interface. A local mass balance
is also ensured but it requires envisaging a protrusion of the minor eutectic phase. The existence of
a lead distance is confirmed experimentally for the (Pb)-(Cd) eutectic system. The difference in
undercooling is also considered as a phenomenon associated with the separation of concentration
fields and the existence of a protrusion to relax the assumption of an isothermal interface (ideally
coupled growth) given by the Hunt and Jackson theory.
Solid-Phase Diffusion Interaction in Multilayer Thin-Film System Cr/Cu/Ni at Pulse Laser Heating
Authors: Vasylyev M. , Nishenko M.M. , Sidorenko Sergey I. , Voloshko S.M.
Published: March 2009

The laser-induced mass transfer in thin-film substrate /Cr/Cu/Ni system is studied by
means of Auger Electron Spectroscopy (AES). For the laser-pulse energy values, E = 100-170mJ,
the diffusion of Cu atoms into Ni layer and their accumulation within this layer are observed,
whereas at E > 170mJ the same is true for Cr atoms. The observed phenomena are explained on the
basis of calculated temperature distribution in the system at issue during lased action. Enhanced
transfer of Cr atoms towards external surface is observed under the irradiation regimes leading to
the melting of intermediate copper layer. Diffusion coefficients of copper and chromium calculated
from their surface accumulation show an exponential dependence on the laser-pulse energy. Under
laser heating, the diffusion processes are more manifested as compared with those under
conventional thermal annealing. This is bound up with higher concentration of nonequilibrium
defects generated within the irradiation zone.
Change of Properties of CMOS Image Sensor Irradiated with 9 and 16 MeV Protons
Authors: Meng Xiang Ti , Huang Qiang , Wang Xing Yu , Zheng Yong Nan , Fan Ping , Zhu Sheng Yun
Published: March 2009

The 9 and 16 MeV proton irradiations of CMOS Image Sensor in the fluence range from 5x108 to 4x1010 cm-2
and 5x109 to 1x1013 cm-2 have been carried out respectively. The color pictures and dark output images are
captured, and the average brightness of dark output images is calculated. The anti-irradiation fluence
thresholds for 9 and 16 MeV protons are about 4x1010 and 5x1012cm-2, respectively. These can be explained by
the change of the concentrations of irradiation-induced electron-hole pairs and vacancies in the various layers
of CMOS image sensor calculated by the TRIM simulation program.
Synthesis of Fe3O4 Nanoparticles Prepared by Various Surfactants and Studying their Characterizations
Authors: Shokuhfar Ali , Alibeigi S. , Vaezi Mohammad Reza , Sadrnezhaad Sayed Khatiboleslam
Published: March 2009

Magnetite (Fe3O4) nanoparticles were prepared simply by the reverse co-precipitation
method from the solution of ferrous/ferric mixed salt in the presence of cationic surfactant (cetyl
trimethyl ammonium bromide, CTAB) and nonionic surfactant (Polyethylene glycol, PEG) in two
concentrations. Meanwhile, Fe3O4 nanoparticles without surfactant are also synthesized under the
same condition for comparison. In addition via the reverse co-precipitation method, the pH which is
an important factor in synthesis of magnetite was controlled at high values easily. The experimental
results reveal that addition of surfactants affected on the size and morphology of the nanoparticles
based on the X-ray diffraction (XRD) and scanning electron microscope (SEM) characterizations.
Nitrogen Diffusion in the Nb-1.0wt%Zr Measured by Mechanical Spectroscopy
Authors: Souza Armando Cirilo , Grandini Carlos Roberto , Florêncio Odila
Published: March 2009

The scientific and technological development in the area of new materials contributed to
several applications of niobium and its alloys in nuclear power plants as well as in aerospace,
aeronautics, automobile and naval industries. This paper presents the interstitial diffusion
coefficients of nitrogen in solid solution in the Nb-1.0wt%Zr alloy using internal friction
measurements obtained by mechanical spectroscopy, which uses a torsion pendulum operating at an
oscillation frequency between 1.0 Hz and 10.0 Hz. The temperature range varies from 300K to
700K, at a heating rate of 1 K/min and vacuum better than 2 x 10-6 Torr. The results showed an
increase of the interstitial diffusion coefficient of nitrogen that was correlated with configurational
considerations for the octahedral interstitials.
Analysis of the Time-Dependent Heating on the Natural Convection from a Vertical Open Ended Porous Cylinder
Authors: Ameziani Djamel Eddine , Bouhadef K. , Bennacer Rachid
Published: March 2009

The problem of unsteady natural convection heat transfer in a vertical opened porous
cylinder submitted to a sinusoidal time variation temperature on the lateral wall has been
investigated numerically. The widely used Darcy flow model without flow establishment at the
cylinder exit has been used. In the case of constant wall temperature, two types of flows were
obtained, with and without fluid recirculation, depending on the filtration Rayleigh number (Ra),
the aspect ratio (A) and the Biot number (Bi) have been obtained. The obtained heat transfer, in case
of low dimensionless oscillations amplitude (XA<0.5), shows a non significant enhancement (less
than 5%) in comparison to the constant wall temperature case.
The Effect of Microstructure Heterogeneity on Fatigue Property of Powder Metallurgy Steels
Authors: Abdoos H. , Khorsand H. , Shahani A.R. , Arjomandi M.
Published: March 2009

Powder metallurgy is a new method for mass production of precision components with
appropriate mechanical properties, but in this kind of materials (PM parts) with special
microstructures (pores act as local stress risers), fracture due to fatigue is expected as an important
destructive factor.
Various microstructures in powder metallurgy steels, depending on alloying methods, have different
response against cyclic loading. diffusion bonding is an effective method to obtain high fatigue
performance in PM steels. The main characteristic of this materials consists of well-organized
phases distribution due to incomplete diffusion of alloying elements.
In this study fatigue behavior of diffusion-bonded, distaloy AE, steel with two carbon contents
under different periodic loading are investigated. The effect of carbon content and various loading
mode upon fatigue performance is analyzed. Metallugraphy and fractography examination on
fatigue loaded samples revealed the positive effect of microstructure heterogeneity on fatigue crack
behavior and this concept is a reason for increasing of diffusion-bonded powders application to
manufacturing of components that are subjected to cyclic stresses.
Thermal Diffusivity of TiAlNb and AlNi Alloys - The European IMPRESS Project
Authors: Matsushita Taishi , Chapman Lindsay , Brooks Rob , Egry Ivan , Seetharaman Seshadri
Published: March 2009

The thermal diffusivities of some industrially important alloys have been measured as a
part of the EU funded Intermetallic Materials Processing in Relation to Earth and Space
Solidification (IMPRESS) project which is coordinated by the European Space Agency (ESA). The
thermal diffusivities of the alloys were measured by the Laser flash method with a carefully
designed gas cleaning system to remove traces of oxygen from the argon atmosphere. In the present
work, the thermal diffusivity of TiAlNb (Ti46.1Al45.9Nb8 at %) and AlNi alloy (Al-Ni31.5 at %)
alloys have been measured independently at Royal Institute of Technology, Sweden (KTH) and
National Physical Laboratory, UK (NPL).
The results from both laboratories were consistent, and have been compared with predictions of
phase transformation temperatures calculated using Thermo Calc and MTDATA software.
Generally the variation of thermal diffusivity appears to be related to the phase transformation.
However, one anomaly observed in the present work on TiAlNb was a maximum thermal diffusivity
value at about 1100K. No corresponding peak was found for the density, ρ, the specific heat
capacity, Cp, or the electrical resistivity, 1/σ, which were also measured as part of the project. In
view of the fact that the thermal diffusivity could be related to electrical conductivity by the
Wiedemann-Franz law describing electronic contribution to heat conduction, the present results
indicate a non-electron contribution. This aspect is being currently investigated further.
The recommended thermal diffusivity value of TiAlNb and AlNi alloys were obtained as
follows.
TiAlNb alloy:
α = 3.75+ 5.16 ·10-3T+1.89·10-6 T2
– 2.69·10-9 T3 [10-6 m2 s-1] (293 K < T < 1573 K)
AlNi alloy:
α = 4.77+ 5.41·10-2T – 7.14·10-5T2 + 2.88·10-8T3 [10-6 m2 / s] (373K <T<943K)
Dominant Factor for the Occurrence of a Steam Explosion
Authors: Min B.T. , Hong S.W. , Kim J.H. , Park I.K. , Kim H.D.
Published: March 2009

For the study of a steam explosion phenomenon in a nuclear reactor, prototypic corium, a
mixture of UO2 and ZrO2 was melted in a cold crucible by applying an induction heating technique.
The molten corium was then poured into cold water. It was fragmented into very small particles, so
called debris, which enables a very rapid heat transfer to the water. Some cases led to steam
explosions by thermal expansion of the water. After the tests, all the debris particles were dried and
classified by their size. From the analysis by using EPMA, it was shown that the particles generated
by a steam explosion had fine and irregular forms. It is known that real corium (including UO2)
hardly leads to a steam explosion, different from pure ZrO2 or metal. A reason for this was
previously suggested in that the corium generated hydrogen gas during melt-water interaction, and it
enclosed the melt drops to prevent a direct contact of the corium and water. In order to confirm this
fact, the debris particles were analyzed with ICP-AES for their typical element contents, EPMA for
the homogeneity of the solid solution, XRD for the chemical compounds, and TGA and hydrogen
reduction analysis for the percentage of the debris oxidation and reduction. These analyses showed
that hydrogen was not directly related to steam explosion. Meanwhile, the material characteristics of
the corium compositions are newly suggested to be the most probable reason for the occurrence of a
steam explosion so far.