bluuebunny/crossref_metadata_2025 huggingface dataset:
TEM Studies on Phase Stability in Nanometer-Sized Alloy Particles
Authors: Lee Jung Goo , Mori Hirotaro
Published: March 2009

TEM is one of the most powerful experimental tools for the study of nanometer-sized particles. In the present work, the finite size effect on both the stability of two-phase microstructure and the solid solubility has been examined by in situ TEM using particles in the Au-Ge system. The size effect on the two-phase microstructure is rather small when the size of particles is larger than approximately 10 nm in diameter. However, the effect becomes strong in particles smaller than about 10 nm in diameter and an amorphous structure appears instead of the crystalline two-phase microstructure. The solid solubility in each solid solution in nanometer-sized alloy particles with a two-phase microstructure gradually increased as the particle size decreased. The enhancement of solid solubility was large in gold solid solution as compared with the in germanium solid solution.
Development of Multi-Phase Intermetallic Alloy Composed of Ni3X-Type Structures
Authors: Takasugi Takayuki , Kaneno Yasuyuki
Published: March 2009

Dual multi-phase intermetallic alloy, which is composed of Ni3Al(L12) and Ni solid
solution (A1) phases at high temperature annealing and is additionally refined by a eutectoid
reaction at low temperature annealing, according to which the Al phase is transformed into the
Ni3Al(L12)+Ni3V(D022) phases, was prepared. High-temperature tension and creep test were
conducted using single crystalline materials. The alloy with such a novel microstructure showed
extremely high yield and tensile stresses with good temperature retention. The creep test conducted
at high temperature showed extremely low creep rate and creep rupture time when compared with
advanced Ni-based superalloys. The results obtained are promising for the development of a
new-type of high-temperature structural materials.
Electrical Property of TiO2 Thin Film Deposited by RF Sputtering
Authors: Niizuma Kiyozumi , Hayakawa Takahiro , Utsushikawa Yoshio
Published: March 2009

The authors investigated on the electrical property and the photo-catalytic activity of
TiO2 thin films deposited in Ar+O2 atmosphere by RF magnetron sputtering. From the result of
x-ray diffraction, the anatase phase was formed in TiO2 thin films. In TiO2 thin film deposited
under a gas pressure of 3.0Pa, the contact angle of water showed 9 ﾟ, and the decomposition rate of
Methylene Blue (measuring the absorbance of the reference light) showed -0.067 with UV light
irradiation. Moreover, it revealed that the electric resistivity of TiO2 thin film deposited under the
same conditions decreased from 8.0×103Ω･m to 1.4×10-2Ω･m with UV light irradiation.
Wear Properties of DLC and Plasma Sprayed WC Structure Coating
Authors: Yatsuzuka Mitsuyasu , Oka Yoshihiro , Tomita Akifumi , Murata Noritaka , Hirota Mitsuaki
Published: March 2009

Diamond-like carbon film (DLC) with an interlayer of plasma sprayed tungsten-carbide
(WC) was prepared on an aluminum alloy substrate (A5052) by a hybrid process of plasma-based
ion implantation and deposition using hydrocarbon gas. Typical thicknesses of DLC and WC films
were 1 μm and 100 μm, respectively. The hardness and friction coefficient of DLC were typically
15 GPa and 0.15, respectively. The durability of DLC/WC/A5052 system was evaluated from the
measurement of the friction coefficient by a ball-on-disk friction tester in which the loaded ball was
drawn repeatedly across a sample and the load was increased with each traverse. For the
DLC/A5052 system, which has no WC interlayer, the DLC film was broken quickly because of
distortion of the substrate. For the DLC/WC/A5052 system, on the other hand, the DLC film was
excellent in durability for long running. The wear rate of rubber rotor to the metal rotor was
measured by a roller-pitching-type wear testing machine, showing large reduction in wear rate using
DLC-coated metal rotor.
Interfaces in Joints and Composites Composed of Hard Materials and Metals
Authors: Tillmann Wolfgang , Gathen Miriam , Osmanda Artur Martin
Published: March 2009

Currently there is an increasing demand for composites and joints composed of hard
materials, such as ceramics, superabrasives or metal-carbides, and metals. Wear pads, welded or
brazed machining tools or composites employed for grinding tools are typical fields of application.
All those various materials solutions have in common that there are interfaces between materials
that typically have a covalent or ionic bonding and metals. Consequently, wetting and bonding
problems arise. The paper presents different examples and discusses them with emphasize on the
corresponding interfacial interactions. Furthermore measures are analysed that can be taken to
influence the intensity and strength of the interfacial bonding between the materials to be joined.
Evaluation of Compound Layer Formed by Impact Welding Using Phase Transformation Technique
Authors: Date Hidefumi , Naka Masaaki
Published: March 2009

When a cylindrical projectile is impact-welded to a flat target, a compound layer is usually
observed at the joining interface as a result of the impact welding. In this study, the formation process of the
compound layer was formulated as a moving boundary problem, which is a phase transformation technique.
The numerical results were compared with the experiment results obtained using an aluminum projectile and
stainless steel target. Numerical analysis shows that the melting area is similar to the temperature profile given
at the boundary face. The area of the compound layer formed at the joining interface almost agrees with the
melting area of the target. The profile of the compound layer is similar to the triangular temperature profile in
the given temperature profiles. The mixing ratio of the melting weights of aluminum and stainless steel
obtained by the numerical analysis strongly depends on the temperature rise at the interface. The melted
weight of aluminum in the experiment is somewhat greater than that in the numerical analysis. The heat
conduction analysis including deformation of the projectile and target make the results of the numerical
analysis closer to the experimental results.
Prediction of Laser Fusion Zone Profile of Lotus-Type Porous Metals by 3D Heat Transfer Analysis
Authors: Tsumura Takuya , Ye Fu Xing , Murakami Taichi , Nakajima Hideo , Nakata Kazuhiro
Published: March 2009

Lotus-type porous metals, whose pores are aligned in one direction by unidirectional solidification, have a unique combination of properties. These are expected as revolutionary engineering materials with anisotropy of the properties. For the industrial use of the lotus-type porous metals, a reliable joining technology is required. We already reported the melting property of a few lotus-type porous metals by laser welding. These results indicated that these materials possessed anisotropy of melting property with the pore direction perpendicular and parallel to the specimen surface, especially remarkable anisotropy was obtained for the copper specimen owing to the difference of the laser energy absorption to the specimen surface. In this report, the three-dimensional heat transfer analyses, which take into account the difference of the laser energy absorption comparing with the anisotropy of thermal conductivity inherent to lotus-type porous metals, were performed by commercial code with user-defined subroutine. Predicted profile of weld fusion zone is in good agreement with the cross-sectional view obtained by experiments.
Resistance Welding by Inserting Wires between Joint Interfaces
Authors: Terajima Takeshi , Kuroda Toshio
Published: March 2009

Butt resistance welding of super duplex stainless steel by inserting type 316L stainless
steel wires was investigated. When the base material temperature was increased from room temperature
to 1100 oC at the heating rate of 550 oC /sec, base materials were jointed through the insert
wires and HAZ (heat affected zone) of the joint interface were less than 80 μm. In this joining technique,
the insert wires played a role of concentrating current on the wires and increasing their temperature
up to melting point or near melting point. When the welding was performed at a load of 10
N, the insert wires consisted of ferrite and austenite growing along the ferrite grain boundary. When
the welding was performed at a load of 70N, insert wire remained austenite. That is because the
contact resistance between insert wire and base materials at 70 N was lower than that of 10 N, and
consequently the insert wire were not adequately heated.
Development of Telerobotic System for Remote Welding Operations in Unstructured Environment
Authors: Wu Lin , Li Hai Chao , Gao Hong Ming , Zhang Guang Jun
Published: March 2009

This paper presents a generic design and implementation of a telerobotic system
application for the remote welding of unstructured and hazardous environment. The objective is to
establish a remote welding telerobotic system that is flexibility to carry out welding seam tracing
and welding remotely. According to the difference of welding task and environment, this paper
presents human machine cooperative control strategies that integrate sensor and model-based
computer assistance. The human operator decision and control commands participate into every
control level of the teleoperation system. The specific control modes have been presented to
integrate into human machine interface (HMI).
Control of Texture in Intermetallic Compounds by Thermomechanical Processing
Authors: Umakoshi Yukichi , Yasuda Hiroyuki Y. , Sakata Toshiya
Published: March 2009

Crystallographic relation between NiAl (β ) grains and Ni3Al (γ ' ) precipitate was
examined using Ni-38at%Al bicrystals with an oriented grain boundary. Microstructure and texture
in B2 type intermetallic compounds such as NiAl and FeAl were controlled by a thermomechanical
process focusing on obtaining highly developed <111> texture and improving ductility.
Characterization of (α+β)/β Transformation in a TC11 Titanium Alloy
Authors: Geng Lin , Xu Bin , Li Y.T. , Li Ai Bin , Wang Gui Song
Published: March 2009

(α+β)/β phase transformation temperature of a TC11 titanium alloy was confirmed to be 1035°C, which was obtained by three methods including the calculation method, differential scanning calorimetry and metallographic techniques. Based on this result, annealing treatments below and above the (α+β)/β phase transformation temperature were carried out, and the microstructure of the TC11 alloys before and after annealing treatment was analyzed by SEM. The result showed that conventional annealing below 1035°C does not change the Widmanstaten structure of TC11 alloy, though the thickness of α lamellar structure becomes thicker with increasing the annealing temperature. The microstructure of the TC11 alloy treated by annealing above the α+β/β transformation temperature is non-uniform because of the different forming temperature and growing duration of α phase in the TC11 alloy.
Hydrogen Permeation in V-Nb Alloys
Authors: Yoshinari Osamu , Yamada Masaaki , Iwata Noriyuki
Published: March 2009

Hydrogen permeation and diffusivity in V1−xNbx alloys (x = 0.25, 0.5 and 0.75) were
investigated over a temperature range between 573 and 673 K. The alloy sheets surface-coated
with Pd (100 nm) by ion-beam sputtering technique were subjected to the hydrogen permeation
measurement with hydrogen pressures less than 3000 Pa. It was found that the hydrogen
permeation is strongly suppressed especially at low hydrogen pressures; the hydrogen permeation is
considered to be controlled by some surface processes. The V0.50Nb0.50 alloy showed the largest
permeability 1.4×10−8 mol H2 m−1s−1Pa−1/2 at 673 K which is larger than that for pure Pd. The
diffusivity which was determined from the fitting of the permeation curve decreases with the alloy
concentration at both the Nb- and V-rich sides and takes a minimum value at x=0.75. The
hydrogen potential obtained by a first-principles calculation showed that V atoms act as trapping
centers for hydrogen in the Nb matrix and Nb atoms act as anti-trapping centers in the V matrix.
Evaluation and X-Ray Induced Modification of the Cerium Oxidation State in Cerium Calixarene Complexes
Authors: Suchorski Yuri , Gottfriedsen Jochen , Wrobel Rafal , Strzelczyk Bartosz , Weiss Helmut
Published: March 2009

The cerium oxidation state in novel calixarene-supported cerium(IV) β-diketonate
complexes [p-tBu-calix[4](OMe)2(O)2]Ce(acac)2 (1) and [p-tBu-calix[4](OMe)2(O)2]Ce(hfac)2 (2),
which are a new class of potential precursors for homogeneous oxidative transformations, has been
determined using X-ray photoelectron spectroscopy (XPS). Cerium oxidation states between 3.6
and 3.65 were detected, distinctly different from their nominal value of +4. An X-ray induced
photoreduction of these compounds was detected. Because of the observed stability of the X-ray
modified oxidation state under ambient conditions this effect might be used for a long-standing fine
tuning of the Ce oxidation state in cerium calixarenes.
Zirconia Based Nanomaterials for Oxygen Sensors – Generation, Characterisation and Optical Properties
Authors: Fidelus Janusz D. , Łojkowski Witold , Millers Donats , Grigorjeva Larisa , Smits Krishjanis , Piticescu Robert R.
Published: March 2009

Microwave driven hydrothermal synthesis and hydrothermal synthesis were used to
obtain ZrO2 nanopowders. Their production with varying phase composition, the characterisation
and selected optical properties concerning their potential use as luminescence oxygen sensors are
reported. It was found that the powders obtained by the microwave driven hydrothermal method
and annealed at 750 0C in air show experiment repeatability within an accuracy of 6 %.
Optical Properties of ZnS:Mn2+ Yellow Nanophosphor Prepared by Spray Pyrolysis
Authors: Lee Sung Hoon , Park Je Hong , Kim Jong Su , Kim Tae Wan , Park Hong Lee
Published: March 2009

Spray pyrolysis was used to prepare ZnS:Mn2+ yellow nanophosphor. As an increase in
firing temperature for spray pyrolysis, more nanoparticles of a hexagonal phase were formed
together with these of the cubic structure. The optimized emission intensity was observed when the
nanophosphor was fired at 900 oC after using a spraying solution of 3.5 pH. The particle size
ranged from 60 nm to 400 nm. The ZnS:Mn2+ nanophosphor showed a redshift of about 10 nm in
the emission spectrum compared to the microphosphor synthesized by solid-state reaction. The
temperature-dependence photoluminescence showed different spectroscopic behaviour and
displayed a longer decay time than the microphosphor.
Effect of the A-Site Randomness on Magnetotransport Properties of PrBaMn2O6 Manganites
Authors: Trukhanov S.V. , Troyanchuk I.O. , Trukhanov A.V. , Szymczak H.
Published: March 2009

A-site ordered PrBaMn2O6 manganites were obtained by a two-step synthesis process.
The chemical composition, crystal structure, magnetic and magnetotransport properties have been
investigated with regard to the degree of ordering of the Pr3+ and Ba2+ cations. A-site disordered
Pr0.50Ba0.50MnO3 has a cubic perovskite-like unit cell (SG = Pm3m , Z = 1), while the A-site
ordered PrBaMn2O6 has a tetragonal unit cell (SG = P4/mmm, Z = 2). The A-site ordered state in
PrBaMn2O6 remains stable on heating to 1300 0C in an oxidizing medium (P[O2] = 1 bar). The
cation ordering leads to a significant increase in the critical temperatures of phase transitions. Asite
ordered PrBaMn2O6 is a metallic ferromagnet with the TC ~ 320 K, whereas TC of a fully
disordered sample is ∼ 140 K. The samples with intermediate degrees of ordering contain two
magnetic phases. Slightly below TC, all samples exhibit a metal–insulator transition and a peak of
the magnetoresistance, amounting to approximately 10 % and 65 % in a magnetic field of 9 kOe for
the fully ordered PrBaMn2O6 and disordered Pr0.50Ba0.50MnO3, respectively. The results are
interpreted in terms of the degree of ordering of the Pr3+ and Ba2+ cations.
FMR Study of Carbon Coated Cobalt Nanoparticles Dispersed in a Paraffin Matrix
Authors: Soboń Marcin , Lipiński I.E. , Typek J. , Guskos Aleksander , Narkiewicz Urszula , Podsiadły Marcin
Published: March 2009

Agglomerated cobalt magnetic nanoparticles coated with carbon, dispersed in a paraffin
matrix, were prepared and investigated by FMR (ferromagnetic resonance) at room temperature.
Four samples with different C/Co content, ranging from 0.175 to 1.011, dispersed at low
concentration in paraffin were investigated. Very intense and broad FMR spectra with different
intensities, line widths and positions of the resonance fields were recorded for the samples. A strong
dependence of the FMR signal intensity and resonance on the concentration of magnetic
nanoparticles was observed. Various magnetic interactions affecting the observed FMR spectra
have been analyzed. It was found that with increasing concentrations of magnetic nanoparticles the
magnetic dipole interaction between the agglomerates plays a more important role.
Catalytic Activity for Methane Flameless Combustion and Thermal Stability of Nano-Sized Lanthanum Cobaltites Doped with Ce, Pr and Tb
Authors: Kryukov A.Y. , Vishniakov A.V. , Oliva Cesare , Forni Lucio
Published: March 2009

High surface area nano-sized catalysts with the general formula La0.9M0.1CoO3 (M=Ce,
Pr, Tb) were synthesised by a novel flame-spray-pyrolysis method. All the prepared samples
possessed the LaCoO3 perovskite-like structure and consisted of 30-60 nm particles, but existing as
large (80-200 nm) agglomerates. Their surface area ranged from 45 to 60 m2/g. All the catalysts
showed a very high activity for methane flameless combustion, attaining 100% conversion at
temperatures Tf, between 495 and 515 0C, depending on the nature of the M doping ion. The results
of life-tests did not show any decreasing of catalytic activity after 50 h under the reaction conditions
at Tf. The thermal stability under high temperature application was investigated by overheating the
catalysts twice at 800 0C for 1 hr in a flowing reacting gas mixture, fast deactivation cycles, and
then measuring methane conversion at Tf. All the catalysts showed a significant decrease of
activity, depending on the chemical composition. Taking account of the results of SEM analysis,
this was attributed to sintering, connected with the Gibbs instability of nano-sized materials.
Vapour Phase Synthesis of Nanocrystalline In Situ YAG:Ce
Authors: Paul Heiko , Kaps Harald , Gleich Thomas , Raeesi Vahid , Herr Ulrich , Zachau M.
Published: March 2009

Nano-crystalline YAG:Ce (Y3Al5O12:Ce) with an average particle size of 10-50 nm was
synthesized by the vapour phase reaction (CVR) in a hot-wall reactor. This nano-crystalline
luminescent material has the advantage of a high light-conversion efficiency associated with
superior light-scattering properties. Phases and compositions were analyzed by XRD and EDX,
respectively. Photoluminescence was used to investigate the optical properties of the YAG host
lattice doped with Cerium. As a first step the conditions for the in-situ production of the YAG
phase were established. On the basis of previous DSC investigations of YAG phase formation, the
DSC results were analyzed according to the Kissinger theory for thermally activated
transformations. From the results it is predicted that, with sufficient heat transfer during the
residence time of the particles in the hot zone of the reactor, YAG can be obtained in-situ during the
CVR process. By modifying the parameters and the CVR setup it was possible to achieve
conditions, which allow the production of in-situ YAG. Samples with Ce doping concentrations
ranging from 0 to 2.65 at.% Ce were prepared to investigate the influence of the doping
concentration on the luminescence of YAG:Ce.
Electro-Mechano-Chemistry; Transport Problem in Four Time Scales
Authors: Danielewski Marek , Pietrzyk Maciej , Wierzba Bartłomiej
Published: March 2009

The mass transport in the presence of stress, electrical, mechanical and chemical potential
gradients in multicomponent solid solution is analyzed. The method bases on the Darken concept
and the calorimetric equation of state. We effectively coupled the conservation of the mass
(continuity equations), energy, momentum and Gauss equations. The diffusion fluxes of the
components are given by the Nernst-Planck formulae and take into account the electro-chemical
and mechanical potentials.
We simulate the deformation field during the diffusion caused by the gradients of the chemical
potential of all elements in non-ideal Fe-Cu-Ni alloy. The simulations show that the model is
compatible with experimental results, and can be effectively used for modelling the energy,
momentum and mass transport problems in compressible multicomponent solid solutions. The
numerical problems and methods of solution are presented.
First Principles Study of Al(100) Twisted Interfaces
Authors: Sot Robert , Piechota Jacek
Published: March 2009

First principles density functional calculations have been performed for a number of
Al(100) twisted interfaces with the purpose to investigate the most stable atomic structures.
Orientation dependence of interface energy normalized to bulk is established and discussed. The
obtained results can be used to model grain growth in molecular dynamics studies.
Mutiscale Plastic Deformation near a Fatigue Crack from Diffraction
Authors: Sun Yinan , Barabash Rozaliya , Choo Hahn , Liaw Peter K. , Lu Yulin , Brown Donald W. , Ice Gene E.
Published: March 2009

After an overload was imposed during a constant amplitude fatigue experiment, a
retardation period was observed. The deformation in the vicinity of a crack tip was studied using
neutron and x-ray microbeam-diffraction techniques, which provide millimeter and submicrometer
spatial resolutions, respectively. From the neutron-diffraction measurements, compressive lattice
strains and higher dislocation densities at the macroscale were observed in front of the crack tip,
which indicates a plasticity induced crack-closure phenomenon. Furthermore, Laue patterns
obtained from the microbeam diffraction at different locations near the crack tip show alternating
regions with high and low dislocation densities at the mesoscale.
Statistical Model of Grain Growth in Polycrystalline Nanomaterials
Authors: Tengen T.B. , Wejrzanowski Tomasz , Iwankiewicz R. , Kurzydlowski Krzysztof Jan
Published: March 2009

Nanomaterials, due to their fine grain sizes, exhibit enhanced mechanical properties.
However, their low stability at also relatively low temperatures might limit their future applications.
In the present work, a statistical model has been proposed in order to study grain growth processes
in nanomaterials. The Hillert’s approach has been extended by incorporating two mechanisms of
growth for an individual grain: grain boundary migration – GBM - (diffusion based - continuous)
and grain-rotation coalescence – GRC - (discontinuous). The influence of the grain size distribution
on the grain growth process has been studied.
The results show that the inclusion of GRC mechanisms results in a departure from the parabolic
law of grain growth. Such a deviation has also been observed experimentally, especially in
nanomaterials. The results reveal that grain growth rate increases with higher dispersion of the fine
grains and the rotation mechanism can initiate growth even with low dispersion. This causes a
steady increase in the coefficient of variation which, after some time interval, decays to
homogeneity. This paper also demonstrates that the average rotation mobility which is a
consequence of the varying misorientation angle contributes up to about 50% of the overall average
boundary mobility.
Concurrent Multiscale Kinetic Monte Carlo-Continuum Models for the Evolution of Solids via Diffusion
Authors: Gill Simon P.A. , Spencer Paul E.
Published: March 2009

A kinetic Monte Carlo (KMC) model for surface diffusion on a 2D lattice is proposed.
An equivalent continuum cellular automaton (CA) model is derived from this. These models are
shown to produce similar results at high temperatures. A hybrid KMC-CA model is derived which
consistently allows material to transfer between a deterministic CA model and a stochastic KMC
model concurrently embedded within it. The quality of the model is demonstrated by simulating the
flattening of a sinusoidal surface profile and the evolution of an elliptical body into a circular one.
Comparison of the Strain Distribution Obtained from Multi Scale and Conventional Approaches to Modelling Extrusion
Authors: Madej Łukasz , Hodgson Peter , Pietrzyk Maciej
Published: March 2009

An investigation of the application of a multi scale CAFE model to prediction of the
strain localization phenomena in industrial processes, such as extrusion, is presented in this work.
Extrusion involves the formation of a strong strain localization zone, which influences the final
product microstructure and may lead to a coarse grain layer close to the surface. Modelling of the
shape of this zone and prediction of the strain magnitude will allow computer aided design of the
extrusion process and optimisation of the technological parameters with respect to the
microstructure and properties of the products. Thus, the particular objective of this work is
comparison of the FE and CAFE predictions of strain localization in the shear zone area in
extrusion. Advantages and disadvantages of the developed CAFE model are also discussed on the
basis of the simulation results.
Multi-Lattice Kinetic Monte Carlo Simulation of Interface Controlled Solid-State Transformations
Authors: Bos C. , Sommer F. , Mittemeijer Eric Jan
Published: March 2009

A kinetic Monte Carlo method has been developed for the simulation of interface
controlled solid-state transformations to overcome timescale limitations associated with other
atomistic simulation methods. In the simulation method the atoms can take place on sites from
(at least) two intertwining crystal lattices. To enable the atoms to also take positions between
the ideal lattice sites, a collection of randomly placed sites can be included. These ‘random
sites’ have a realistic chance to be occupied at the location of the transformation interface and
thus allow for irregularities in the atomic structure of the transformation interface. The atoms
move by independent, thermally activated jumps. The activation energy for the atomic jumps
can be determined for every jump separately based on the arrangement of the neighbouring
atoms. The simulation method has been used to study the interface mobility in the austenite to
ferrite transformation in iron for different interface orientations. The results obtained indicate
that the excess volume associated with the interface plays a key role for the activation enthalpy
for the interface mobility. The rate controlling process is the rearrangement of free space at the
interface by series of (unfavourable) jumps by different atoms to create a path from the parent
to the product phase.
Interdiffusion of Two L10Phases without Long-Range Order Decrease: Experiments and Molecular Dynamics Simulations
Authors: Goyhenex Christine , Montsouka R.V.P. , Kozłowski Mirosław , Pierron-Bohnes Veronique
Published: March 2009

The L10 ordered MPt(001) thin films (M = Fe or Co) are very interesting for
perpendicular recording due to their magnetic anisotropy and magneto-optical behaviours.
Epitaxial L10-ordered NiPt(001) / FePt(001) bi-layers were co-deposited on MgO(100)
substrates by MBE. The L10 order parameter is high with the concentration modulation along
the growth direction. Some FeNiPt2(001) thin films were obtained by interdiffusion of the bilayers.
The long-range-order parameter is conserved after interdiffusion (S = 0.75 ± 0.06),
which can be explained by different mechanisms: a second-neighbour jump, a six-jump cycle,
an anti-structural bridge mechanism or an antisite-pair elimination and creation mechanism, a
double vacancy or a triple defect diffusion mechanism. Quenched molecular dynamics
calculations in the frame of the second moment approximation of the tight binding method
have been performed to obtain the energetic paths of the different mechanisms. The secondneighbour
vacancy jump, the simultaneous jumps of bivacancies and the triple defect
mechanisms can be ruled out for energetic reasons.
A Phase Field Model for grain Growth and Thermal Grooving in Thin Films with Orientation Dependent Surface Energy
Authors: Moelans Nele , Blanpain Bart , Wollants Patrick
Published: March 2009

A phase field model for simulating grain growth and thermal grooving in thin films
is presented. Orientation dependence of the surface free energy and misorientation dependence
of the grain boundary free energy are included in the model. Moreover, the model can treat
different mechanisms for groove formation, namely through volume diffusion, surface diffusion,
evaporation-condensation, or a combination of these mechanisms. The evolution of a groove
between two grains has been simulated for different surface and grain boundary energies and
different groove formation mechanisms.
An Extensive Study of Charge Effects in Silicon Doped Heterofullerenes
Authors: Matsubara Masahiko , Massobrio Carlo
Published: March 2009

We present an analysis of charge effects on the highly silicon doped heterofullerenes
C30Si30. Structural and electronic properties are investigated by the inclusion of an extra pos-
itive and negative charge in the neutral system. The calculations are performed based on the
framework of Car-Parrinello molecular dynamics within the spin density version of density
functional theory. Structural properties are not significantly affected by adding to or extracting
from the C30Si30 heterofullerene one electron. However, the change of charge states has some ef-
fects on the electronic properties of heterofullerenes. In the negatively charged system, negative
charges are found in the inner part of the Si region, thereby suggesting potential applications
of Si-based heterofullerenes as anionic systems.
Structural Refinement and Homogeneity Range of Sm6Al3Si
Authors: Pikus Stanislaw , Melnyk Ihor , Gladyshevskii Roman E.
Published: March 2009

The structure of the compound Sm6Al3Si was refined from X-ray powder diffraction data (Tb6Al3Si structure type, space group I4/mcm, a = 11.733(1), c = 15.266(2) Å, Z = 8, RB = 0.0569). Its homogeneity range extends from 10 to 22 at.% Si and the following formula Sm6Al3-1.8Si1.0-2.2 is proposed for the compound studied. The Al and Si atoms are surrounded by Sm atoms forming trigonal prisms, square prisms and antiprisms.
Morphology of Precipitates in Ni-Al-Cr Intermetallic Alloy
Authors: Pilawa Mirosław , Jezierska Elżbieta
Published: March 2009

Transmission electron microscopy was used to study various morphologies of ordered
precipitates in Ni3Al-Cr intermetallic alloy. It was found that γ’ precipitates in the interdendritic
regions have the microstructure of a nickel base superalloy with its characteristic features. In
addition to the primary γ’ precipitates some fine secondary precipitates were found.
Precipitation of Phases in Al-Mg-Si-Cu Alloy with Sc and Zr Additions during Heat Treatment
Authors: Lityńska-Dobrzyńska Lidia
Published: March 2009

In the present work the sequence of phases in Al-1%Mg-0.6%Si-1%Cu (in wt %) alloys
with 0.4%Sc and 0.2%Zr additions during heat treatment has been studied. The investigated alloys
were cast into copper mould to ensure high cooling rate during solidification and the retention of Sc
and Zr in the supersaturated solid solution. Two−step preliminary heat treatment was applied: the
annealing at temperature 300°C or 350°C followed by quenching from 540°C to water. The
precipitation of the Q′ and Al3Sc phases has been observed during the first step of annealing. The
annealing at 540°C has led to complete dissolution of the Q′ particles and growth of the spherical
particles of the Al3Sc phase. The increase of hardness during subsequent ageing at 165°C (typical
ageing temperature of the 6xxx alloys) has been caused by the formation of needle-like Q′ phase
which coexist with Al3Sc precipitates.
TEM Investigations of Electron 21 Magnesium Alloy
Authors: Kiełbus Andrzej
Published: March 2009

The paper presents results of TEM investigations of Elektron 21 magnesium alloy in as
cast condition and after heat treatment. The compositions of the Elektron 21 alloy used in the
present study was Mg-2,7%wtNd-1,2%wtGd-0,47%wtZr. Solution heat treatment was performed at
520°C/8 h/water. Ageing treatments were performed at 200°C/4÷96h and 300°C/48h with cooling
in air. The as-cast microstructure and microstructural evolution during heat treatment were
examined by transmission electron microscopy. Samples were prepared using Gatan PIPS ion mill.
Examinations were performed in a JEM 2010 ARP microscope. The microstructure of the cast alloy
consists of a-Mg phase matrix with precipitates of Mg12(Ndx,Gd1-x) phase at grain boundaries. After
solution treatment the Mg12(Ndx,Gd1-x) phase dissolved in the matrix. The ageing treatment
applied after solution treatment with air-cooling caused precipitation of a β’ and β phases.
Preparation of MgB2 Rods Using a PIT Technique with the Explosive Consolidation Method
Authors: Orlińska Natalia , Paszula Józef M. , Wokulski Zygmunt , Dercz Grzegorz
Published: March 2009

It was successfully prepared superconducting MgB2 rods with two double arrangements
of tubes such as: Cu/Fe and Steel/Cu by the modified Powder-In-Tube (PIT) technique with
explosive consolidation method. The metallographic observations and X-ray phase analysis of the
obtained MgB2 rods were performed. These studies show that this type of consolidation permits to
obtain MgB2 rods free from any voids and new phases.
Preparation of Co1-xFexSi2 Solid Solution Crystals
Authors: Wokulski Zygmunt , Gurdziel Wojciech , Krawczyk Jacek , Szostek Krzysztof
Published: March 2009

The main goal of paper was obtaining of solid solution Co1-xFexSi2 crystals from liquid phase by Bridgman method. There are presented features and quality parameters of obtained ingots. It was found that the substitutional solid solution Co1-xFexSi2 crystals can be obtained only for x = 1at.% Fe.
Poly(Ethylene Oxide)/Styrene Ionomers Blends: Crystallization of Poly (Ethylene Oxide) Component Studied by Wide-Angle X-Ray Diffraction
Authors: Ślusarczyk Czesław , Suchocka-Gałaś Kazimiera
Published: March 2009

Wide-angle X-ray diffraction (WAXD) and the scanning electron microscopy (SEM) were used to determine the morphology of crystalline phase of blends of poly(ethylene-oxide) (PEO) and styrene-acrylic acid (S-AA) copolymers neutralized with sodium ions (Na+). In this study, we investigated the effects of blend composition and the content of ionic groups in amorphous ionomers on the degree of crystallinity and the crystallite sizes. It was found that the degree of crystallinity of PEO in the blends decreases both with increasing S-ANa(6.4) content and with increasing ANa content. The sizes of PEO crystallites, measured both in the direction perpendicular and parallel to the polymer axis, are almost independent of ionic groups content in the amorphous component of the blends but they decrease with increasing S-ANa(6.4) content. For the blends containing small amounts of PEO the confined crystallization of this polymer were observed. The final crystalline morphology of these blends, observed by SEM method, is different in comparison to that formed without spatial confinement.
Lattice and Peak Profile Parameters in GIXD Technique
Authors: Goryczka Tomasz , Dercz Grzegorz , Pająk Lucjan , Łągiewka Eugeniusz
Published: March 2009

Grazing incident X-ray diffraction technique was applied to determine the influence of
incident beam angle (α angle) on structural parameters as well as peak profile. X-ray diffraction
patterns were registered in asymmetrical geometry, in which a parallel beam was formed by Soller
and divergence slits. Lowering of the α angle results in accuracy decrease of lattice parameters as
well as in significant broadening of a half-width of X-ray diffraction line.
Quasiperiodic Photonic and Phononic Crystals
Authors: Steurer Walter , Sutter-Widmer Daniel
Published: March 2009

The main advantage of quasiperiodicity for the design of photonic and phononic crystals is the arbitrarily high rotational symmetry, which can be achieved without sacrificing a discrete Fourier (Bragg) spectrum. Consequently, the degree of isotropy can be arbitrarily increased leading to omnidirectional bandgaps. These are important for most applications as for instance wave-guides or -shields.
Rolling Texture Differences in Duplex Steels with Strong and Random Initial Orientations
Authors: Ryś Janusz , Ratuszek Wiktoria , Witkowska Małgorzata
Published: March 2009

The present examination concerns a comparison of rolling texture development in two stainless steels of duplex type with different intensities of ferrite and austenite initial textures after a preliminary treatment, namely; clearly defined strong textures of both phases in one steel and nearly random textures in the case of the second one. Essentially the constituent phases in both duplex steels tend to develop the rolling textures comparable with those in single phase steels. However, the final textures display certain differences in comparison to the typical ferrite and austenite rolling textures. In both duplex steels the formation and character of the final deformation textures is strongly influenced by the band-like morphology of the ferrite-austenite structure and the process of texture formation proceeds in different way depending on the initial orientation distribution.
Precise Lattice Parameters of the Sr0.61Ba0.39Nb2O6 Single Crystal
Authors: Pacek Paweł , Wokulska Krystyna , Dec Jan , Łukasiewicz Tadeusz
Published: March 2009

Single crystals of composition Sr0.61Ba0.39Nb2O6 (space group P4bm) were prepared using the Czochralski method. The Bond's method of the precise lattice parameter measurements was used to study structure of SBN 61 at room temperature. In this way lattice parameters a = b = 12.45676 ± 6*10-5Å and c = 3.93541 ± 5*10-5Å were determined.
X-Ray Analysis of the Cd0.5Ge0.5Cr2Se4 and CdCr1.9Ge0.075Se4 Compounds
Authors: Maciążek Ewa , Goryczka Tomasz , Jendrzejewska Izabela
Published: March 2009

The polycrystalline Cd0.5Ge0.5Cr2Se4 and CdCr1.9Ge0.075Se4 compounds were obtained using ceramic method. X-ray analysis was used to make phase and structure analysis. The Rietveld method was applied for structure refinement. Both compounds crystallized in cubic, normal spinel structure, Fd 3m. Besides the main spinel phase, Cr2Se3 was observed.
Comparison of Defects Created by Plasma-Based Ion Implantation and Conventional Implantation of Hydrogen in Germanium
Authors: David Marie-Laure , Pailloux Frédéric , Drouet Michèl , Beaufort Marie France , Barbot Jean François , Simoen Eddy , Claeys Cor
Published: March 2009

(001) n-type Ge has been implanted at given fluence and intermediate temperature with
hydrogen ions using two processes: conventional in-line implantation and plasma based ion
implantation. The as-created microstructure has been compared using transmission electron
microscopy. In particular, it has been shown that the major differences observed are due to the
implantation temperature, much higher during the PBII process. This suggests that plasma based ion
implantation could be used for layer transfer in spite of a higher surface roughness observed after
the PBII process.
Formation of Hydrogen-Related Shallow Donors in Ge1-xSix Crystals Implanted with Protons
Authors: Pokotilo Yurii M. , Petukh Alla N. , Litvinov Valentin V. , Markevich Vladimir P. , Abrosimov Nikolay V. , Peaker Anthony R.
Published: March 2009

It is found that shallow hydrogen-related donors are formed in proton-implanted dilute
Ge1-хSiх alloys (0 ≤ x ≤ 0.031) as well as in Si-free Ge samples upon heat-treatments in the
temperature range 225-300oC. The maximum concentration of the donors is about 1.5×1016 cm-3 for
a H+ implantation dose of 1×1015 cm-2. The temperature range of formation of the protonimplantation-
induced donors is the same in Ge1-xSix samples with different Si concentration.
However, the increase in Si content results in a decrease of the concentration of the hydrogenrelated
donors. It is argued that the H-related donors could be complexes of Ge-self-interstitials
with hydrogen atoms. The observed decrease in the concentration of the donors with an increase in
Si content in the Ge1-xSix samples is associated with interactions of mobile hydrogen atoms with Si
impurity atoms. Such interactions reduce the number of implanted hydrogen atoms that can be
involved in defect reactions resulting in the formation of H-related shallow donors.
Microwave and Infra Red Light Absorption Studies of Carrier Lifetime in Silicon and Germanium
Authors: Gaubas Eugenijus , Vanhellemont Jan
Published: March 2009

Results are presented of a comparative study of carrier lifetime in silicon and germanium.
The impact of surface quality and passivation, of dopant type and concentration and of metallic
impurities is studied using microwave probed free carrier absorption transient techniques.
Impact of Iron and Molybdenum in Mono and Multicrystalline Float-Zone Silicon Solar Cells
Authors: Coletti Gianluca , Geerligs L.J. , Manshanden P. , Swanson C. , Riepe Stephan , Warta Wilhelm , Arumughan J. , Kopecek R.
Published: March 2009

This paper investigates the impact of iron (Fe) and molybdenum (Mo) when they are
introduced in the feedstock for mono- and multicrystalline Float-Zone (FZ) silicon (Si) growth.
Neutron Activation Analysis shows that the segregation coefficient is in agreement with literature
values. Lifetime maps on monocrystalline wafers show a uniform lifetime which decreases with the
increase of contamination levels. Multicrystalline wafers show low lifetime areas, corresponding to
grain boundaries and highly dislocated areas, which are independent from the contamination levels.
Intra grain areas have a higher lifetime which changes with the contamination levels. The solar cells
show a reduced diffusion length in multicrystalline uncontaminated cells compare to the
monocrystalline uncontaminated. In multicrystalline cells the lowest level of Fe introduced (1012
atm/cm3) has hardly any influence, whereas in the Mo-contaminated cells the impact is visible from
the lowest level (1011 atm/cm3). In monocrystalline cells the diffusion length is reduced already at
the lowest contamination level of Fe.
Radiation Defects and Thermal Donors Introduced in Silicon by Hydrogen and Helium Implantation and Subsequent Annealing
Authors: Hazdra Pavel , Komarnitskyy Volodymyr V.
Published: March 2009

The effect of high-energy hydrogen and helium implantation and subsequent annealing on
generation of radiation defects and shallow donors in the low-doped oxygen-rich FZ n-type silicon
was investigated. Samples were implanted with 7 MeV 4He2+ or 1.8 MeV 1H+ to fluences ranging
from 1x109 to 3x1011 cm-2 and 1.4x1010 to 5x1012cm-2, resp., and then isochronally annealed for 30
minutes in the temperature range up to 550°C. Results show that radiation damage produced by
helium ions remarkably enhances formation of thermal donors (TDs) when annealing temperature
exceeds 375°C, i.e. when the majority of vacancy-related recombination centers anneals out. The
excess concentration of TDs is proportional to the helium fluence and peaks at 1.6x1014cm-3 if
annealing temperature reaches 475°C. Proton irradiation itself introduces hydrogen donors (HDs)
which form a Gaussian peak at the proton end-of-range. Formation and annealing of shallow and
deep hydrogen-related levels are strongly influenced by electric field at annealing temperatures
below 175°C. If annealing temperature exceeds 350°C, HDs disappear and the excessive shallow
doping is caused, as in the case of helium irradiation, by radiation enhanced TDs.
First-Principles Simulations of Frenkel Pair Formation and Annealing in Irradiated ß-SiC
Authors: Pizzagalli Laurent , Lucas Guillaume
Published: March 2009

Using first principles molecular dynamics and Nudged Elastic Band calculations, we
have investigated the effect of irradiation on cubic silicon carbide at the atomic scale, and in
particular the formation of Frenkel pairs, and the crystal recovery after thermal treatment. Threshold
displacement energies have been determined for C and Si sublattice, and the stability and structure
of the formed Frenkel pairs are described. The activation energies for annealing these defects have
then been computed and compared with experiments.
Modeling of the Diffusion and Activation of Arsenic in Silicon Including Clustering and Precipitation
Authors: Martinez-Limia Alberto , Pichler Peter , Steen Christian , Paul Silke , Lerch Wilfried
Published: March 2009

We have developed a diffusion and activation model for implanted arsenic in silicon. The
model includes the dynamic formation of arsenic-vacancy complexes (As4V) as well as the precipitation
of a SiAs phase. The latter is mandatory to correctly describe concentrations above solid
solubility while the former are needed to describe the reduced electrical activity as well as the generation
of self-interstitials during deactivation. In addition, the activation state after solid-phase epitaxy
and the segregation at the interface to SiO2 are taken into account. After implementation using
the Alagator language in the latest version of the Sentaurus Process Simulator of Synopsys, the parameters
of the model were optimized using reported series of diffusion coefficients for temperatures
between 700 °C and 1200 °C, and using several SIMS profiles covering annealing processes
from spike to very long times with temperatures between 700 °C and 1050 °C and a wide distribution
of implantation energies and doses. The model was validated using data from flash-assisted
RTP and spike annealing of ultra-low energy arsenic implants.
The Temperature Evolution of the Hydrogen Plasma Induced Structural Defects in Crystalline Silicon
Authors: Nordmark Heidi , Ulyashin Alexander G. , Walmsley John Charles , Holt Arve , Holmestad Randi
Published: March 2009

Hydrogenated n and p doped Czochralski Si substrates have been studied by means of atomic force
microscopy, scanning and transmission electron microscopy, Raman spectroscopy and microwave
photoconductivity decay techniques. The measurements show that the surface is roughest in ndoped
samples which are plasma treated at high frequency. The cone density was found to be
highest on p-doped samples, which correlates well to the higher density of defects observed in pdoped
samples. The surface cones were found to consist of nanograins, twins and stacking faults
with random orientations, several hydrogen induced defects and bubbles. The size, density and
formation depth of the subsurface defects were seen to depend on doping type, doping level, plasma
frequency and hydrogenation time. Raman spectroscopy shows formation of nearly free hydrogen
molecules, which are presumed to be located in nano-voids or platelets. These molecules dissolved
at temperatures around 600°C. By means of the &-PCD measurements, it is demonstrated that
hydrogen-initiated structural defects act as active recombination centres, which are responsible for
the degradation of the minority carrier lifetime.
Structure of Magnetically Ordered Si:Mn
Authors: Bak-Misiuk Jadwiga , Dynowska Elżbieta , Romanowski Przemyslaw , Shalimov A. , Misiuk Andrzej , Kret S. , Dłużewski P. , Domagala J. , Caliebe Wolfgang , Dabrowski Jerzy , Prujszczyk M.
Published: March 2009

The structure studies of single crystalline silicon implanted at 340 K or 610 K with Mn+
ions (Si:Mn) and subsequently processed under atmospheric and enhanced hydrostatic pressure at
up to 1270 K are reported. The defect structure was determined by an analysis of
X-ray diffuse scattering around the 004 reciprocal lattice point and by electron microscopy. High
resolution X-ray diffraction techniques based on the conventional source of radiation were used for
this purpose. The crystal structure of Si:Mn and the Si1-xMnx precipitates in the implantation –
disturbed layer were studied by synchrotron radiation diffraction in the grazing incidence
geometry. Processing of Si:Mn results in crystallization of amorphous Si within the buried
implantation – disturbed layer and in formation of Mn4Si7 precipitates. Structural changes are
dependent both on temperature of the Si substrate at implantation and on processing parameters.