bluuebunny/crossref_metadata_2025 huggingface dataset:
A Study on the Factors Affecting the Formability of TMCP Steel for Curved Hull Plate
Authors: Shin Sang Beom , Kim Ha Geun , Kim Kyeong Gyu
Published: March 2009

The purpose of this study is to identify the principal factors controlling the formability of
TMCP steel for curved hull plate. In order to do it, the initial residual stress in TMCP steel was
evaluated using flatness measured in the flat bar cut by flame and analytical approach. Changes of
the curved profiles in conventional steel and EH 36 TMCP steel of 50mm thick during cold bending
and local heating were investigated using 3 dimensional measuring instruments. It was found that
the formability in TMCP steel was mainly determined by the excessive distortion by the relaxation
of residual stress during cold bending.
Magnetostrain in Multifunctional Ni-Mn Based Magnetic Shape Memory Alloys
Authors: Mañosa Lluís , Moya Xavier , Planes Antoni , Aksoy Seda , Acet Mehmet , Wassermann Eberhard F. , Krenke Thorsten
Published: March 2009

We report on strain measurements in Ni-Mn-Ga, Ni-Mn-In, Ni-Mn-Sn and Ni-Mn-Sb
polycrystalline alloys as a function of temperature and magnetic field. Experiments are carried out
in the austenitic and martensitic phases of the alloys. It is shown that in the cubic phase the
magnetostrain is similar for all systems but by contrast very different behaviour is found when a
field is applied in the martensitic phase. In the latter case, magnetic shape memory and magnetic
superelasticity is obtained for Ni-Mn-Ga and Ni-Mn-In, respectively. The physical reasons for the
different behaviour are discussed.
Mechanical Properties of Epoxy Composites Filled with Short Steel Fibres for Hybrid Injection Moulds
Authors: Sabino-Netto Aurélio C. , Salmoria Gean V. , Ahrens Carlos H. , Pouzada António Sergio
Published: March 2009

Epoxide filled composites are being increasingly used for mouldings blocks of hybrid
injection moulds. The filling is sought for improving both mechanical and thermal properties that
are relevant for the mould performance. In spite of several works investigating the particulate filling
of resins, there are only a few reports on fibre reinforcement. Composites based on an epoxy system
with varying volume fractions of short steel fibres (SSF) were investigated. The mechanical
properties were determined for each composite, and the topography of the fracture surfaces was
analyzed by SEM. The mechanical properties of the epoxy filled composites were also compared to
commercial particulate composites that are used for producing casting moulds. In spite of the SSF
being more difficult to mix that the usual metal particulate fillers, it was found that the resulting
composites show some improvement in the mechanical properties.
New Powder Coating Equipment to Produce Continuous Fibre Thermoplastic Matrix Towpregs
Authors: Silva R.F. , Silva João F. , Nunes João Pedro , Bernardo Carlos A. , Marques António Torres
Published: March 2009

Thermoplastics are replacing traditional thermosetting resins as matrices in composite
materials in many applications due to their enhanced properties. Thermoplastics exhibit better
toughness, durability and damping properties and provide the options of continuous processing,
reshaping, and reparability, as well as more favourable recycling and processing routes that do
not involve chemical reactions [1]. However, their high melt viscosity makes it difficult to
impregnate continuous fibres, which restricts commercial applications.
Recently developed dry coating techniques allow the production of long fibre
thermoplastic matrix towpregs without most of the previous impregnation problems [2, 3]. In this
work, a new coating line was developed to produce long fibre dry coated thermoplastic matrix
towpregs at rates compatible with industrial production. The polymer deposition rate was
considerably increased to allow processing towpregs at greater speeds (approx. 10 m/min) than
current equipment. A new coating chamber was used to allow improved control of the fibre and
polymer contents and the towpreg impregnation quality. Other general improvements were also
made in the equipment to allow better monitoring of the towpreg processing.
Glass or carbon fibres with polypropylene towpregs (GF/PP and CF/PP, respectively)
were produced on the new coating line which were then submitted to extensive tests to verify
their polymer content and impregnation quality.
This paper presents the results of the tests and discusses the optimization of the new dry
coating line. The results show that the new deposition chamber allows production of economical
thermoplastic matrix towpregs with improved efficiency that may be used in the industrial
production of composites for commercial markets.
Melting of PP/PA6 Polymer Blends in Single Screw Extruders – An Experimental Study
Authors: Cunha S.M. , Gaspar-Cunha António , Covas José A.
Published: March 2009

A prototype modular single screw extruder fitted with a screw extracting device is used
to monitor melting of an immiscible polymer blend (PP/PA6, with different weight ratios) in this
widely used processing equipment. As anticipated, the phenomena observed are much more
complex than those involved in extruding PP or PA6, when the well known Maddock/Tadmor
mechanism is valid. Consequently a hybrid melting mechanism, involving Maddock/Tadmor and
Dispersive melting sequences, is proposed.
Improvement of Insulation Properties of Conventional Brick Products
Authors: Bánhidi Viktor , Gömze László A.
Published: March 2009

The use of technologically byproduct agricultural wastes in various segments of the brick
and tile industry is increasing continuously. The additives, mixed into the raw clay ignite during the
firing process, adding extra thermal energy from inside the mixture decreasing the energy
requirements of the manufacturing process. Added to this, through the combustion of the bio-wastes
the porosity increases enhancing the thermal insulation properties of the final product. We have
investigated some common, agricultural wastes to determine their effect on the thermal properties
of bricks. In our experiments industry relevant amounts of additives (sawdust, rice-peel, seed-shell)
were added to the basic clay composition. We have prepared mixtures with additive concentrations
of 0, 4, 7 percentage by weight. The preparations of the samples were (milling, drying and firing)
following industrial standard procedures. Precise thermal conductivity data were gathered from all
samples using a RAPID-K type static thermal conductivity measuring instrument. Our
measurements show that by increasing the amount of the organic byproducts in the clay mixture it is
possible to significantly decrease their thermal conductivity, leading to an improved insulation
capability of commercial brick products. On the other hand, there was only a minor reduction in the
mechanical strength found during previous works. The investigated agricultural byproducts were
also ranked based on their effect on the product's thermal properties. It was found that the largest
decrease to the thermal conductivity was caused by the sunflower seed-shell additive. Mixing 7 %
wt. seed shell to the clay, we can decrease the thermal conductivity of the fired product from
0,27 W/m·K to 0,17 W/m·K (36%). We have found that under the same conditions the sawdust
caused the least improvement, only a decrease of 0,27 W/m·K to 0,23 W/m·K (16%) was measured.
Composite Production by Pressure Infiltration
Authors: Orbulov Imre Norbert , Németh Árpád , Dobránszky János
Published: March 2009

This paper presents the possibility of composite block production by using pressure
infiltration technology. This method uses the pressure of an inert gas (usually argon or nitrogen) to
force the melted matrix material to infiltrate the reinforcing elements. Three types of materials were
considered: open cell metallic foam, metal matrix syntactic foam and carbon fiber reinforced metal
matrix composite. Physical and mechanical investigations – such as SEM and compression tests –
were performed. The results of measurements were summarized briefly.
Systematic Examination of Metallographic Methods for Detection of Primary Steel Texture
Authors: Kardos Ibolya , Verő Balázs , Csepeli Zsolt , Réger Mihály
Published: March 2009

In spite of speedy development of technical tools for examination, the importance of
macro structural investigation has not decreased; on the contrary, these methods are in the state of
their revival. One of evident reasons for it is the fact, that the results of macro structural
examinations and the conclusions drawn from them are in the closest relation with the parameters of
technology, reflect their changes, and the deviations from the specified values. It is expedient from
time to time to check the methods proved earlier suitable for macro structural investigation,
possibly to develop and implement new methods. We have to take in account that the methods now
widely applied were developed when the technology, composition, type and quantity of pollutants
were still basically different from those of the present. We mention as an example that in the
fundamental work of George F. Vander Voort published in 1984 the examinations of
macrostructure of continuously cast semi products occupied hardly one to two pages, while
nowadays they produce about 90% of the annual 1.1 billion tonne steel quantity in continuous
casting plants, thus the decisive proportion of continuously cast semi products examination can
hardly be questioned. Taking in consideration the above points of view, in the frame of a
consortium work we examined the macrostructure of samples taken from bloom slabs cast on
vertical continuous casting machine from nine consciously chosen charges, with methods known
from the literature or personal information.
A New Technique for Characterization of Residual Stresses in Glass Surfaces: Scratch Test Completed with Image Analysis
Authors: Szeghalmy Szilvia , Barkóczy Péter , Maros Maria Berkes , Fazekas Attila , Póliska Csaba
Published: March 2009

Residual stresses significantly influence the strength and lifetime of the glass products,
therefore their qualification and quantification during production is basically important for
evaluating their probable reliability in application. The current paper aims at introducing a novel
procedure of the suggested automatic glass quality test based on instrumented scratch test
completed with computer aided image analysis. A special emphasis is put on the problem of limited
reproducibility and reliability of the image processing, arisen in the first stage of the research work.
The latest results consisting in the development of a new algorithm, providing a more reliable
evaluation of the test data will be described.
Investigation of Time-Dependent Behavior of Starch-Based, Injection Molded Biodegradable Polymer
Authors: Tábi Tamás , Tuba Ferenc , Oláh László
Published: March 2009

Nowadays as a result of the increasing environmental friendly consciousness and the
decreasing oil reserves, natural origin based materials are developed. These materials are not only
based on renewable, natural resources, but capable of biodegradation in compost. These
biodegradable polymers (biopolymers) can be inserted into the nature’s recycling process. One of
the most important biopolymers is starch. Starch can be processed like a thermoplastic material by
adding plasticizers, creating the so called thermoplastic starch. However the price of starch is rather
low, it has certain drawbacks retarding its wide industrial usage. It is sensitive to moisture, disrupts
in pure water, has low mechanical properties, and in time it ages. This ageing or time-dependent
behavior was analyzed with injection molded tensile specimens. The shrinkage and mechanical
properties of the specimens were determined as a function of ageing time. The fracture surface was
analyzed by scanning electron microscope. The results of the measurements were compared with
previous examinations.
Investigation of Drug Eluting Stents
Authors: Bognár Eszter , Ring György , Balázs Tibor , Dobránszky János
Published: March 2009

The clinical results of drug eluting stents [DESs] depend on the type of the coating, the
coating technology and the dosage and efficiency of the drug. The current study shows our
examinations on drug eluting stents. Different types of commercially available coronary stents were
investigated. Various methods were used for these experiments, for example optical microscopy,
confocal fluorescent microscopy, scanning electron microscopy and EDS analysis. The properties
characterizing applicability of drug eluting stents and the changing of the coatings during expansion
are shown.
Laser Cutting of High Precision Tubes
Authors: Meszlényi György , Dobránszky János , Puskás Zsolt
Published: March 2009

This paper gives an overview of the laser cutting equipment developed for stent cutting:
Nd:YAG, fiber and water-jet guided lasers; work piece positioning systems and different materials
for stent manufacturing were presented. The side effects of laser cutting like oxide layer, heat affected
zone and dross deposition were examined. Pulsed Nd:YAG laser cutting of AISI 304L type
austenitic stainless steel high precision tube with 1,800 mm diameter and 0,117 mm wall thickness
was performed. The relationship between the average power and kerf was characterised.
Numerical Analysis of Metal Powders in Uniaxial Compaction
Authors: Schaerer Magna Monteiro , Roehl Deane , Silveira José Luís
Published: March 2009

Powder consolidation constitutes an important step in the manufacture of products of
high quality and precision. To obtain these components, with desired forms and final mechanical
properties, it is of extreme importance to have knowledge about the processes to obtain powders,
compacting and sintering. The objective of this work is to verify which model, obtained from the
literature, better describes the compaction densification behavior of iron powder in closed-die.
Doraivelu’s criterion was carried through the method of the finite elements with the implementation
of an elastoplastic model with hardening. The influence of the yield function coefficient against the
relative density was evaluated, as well as, the yield function in the hydrostatic space.
Spray-Dried YSZ Ceramic Powders: Influence of Slurry Stability on Physical Characteristics of Agglomerates
Authors: Santana L.P. , Lazar Dolores Ribeiro Ricci , Yoshito Walter Kenji , Ussui Valter , Paschoal José Octavio Armani
Published: March 2009

Zirconia stabilized with 8 mol% yttria (YSZ) is the most effective material for use as
electrolytes in solid oxide fuel cell. Ceramic powders of YSZ were synthesized in IPEN by
coprecipitation route and are composed by fine particles (less than 01μm) with large surface area
(~60m2.g-1). These powders have a strong tendency to agglomerate. and it make difficult the
compaction process and to achieve a good density. To exert control over the compaction process.
the powders were spray dried to obtain spherical granules. Thus the stability of slurries of these
powders was studied by adding ammonium polyacrylate (Duramax D3005) as dispersant and the
suspension stability was measured by electrophoretic mobilities. Slurries prepared with the better
conditions were dried in a laboratory scale spray dryer. The prepared granules were characterized
by morphology observation (SEM). surface area (BET). Vickers hardness and sintered ceramics
bodies density were measured.
Thermal and Physico-Mechanical Characterization of Paraíba’s State Soils to Applying in Soil-Cement Bricks
Authors: da Silva Morais Crislene Rodrigues , Leite Marcelo Rodrigues , de Figueiredo L. Lucena Luciana , Rocha do Nascimento Railda Shelsea T.
Published: March 2009

Soils play a decisive role in the manufacture of building materials, especially, tiles and
bricks. Production techniques cause negative impacts on the environment and add additional time to
the production process. Three samples obtained from Paraíba State were characterized by thermal
characterization, granulometric and physical-mechanical techniques. Thermal analysis was
undertaken in two different atmospheres, at a flow rate of 110 ml/min and a heating rate of
10oC/min. Evaluation of the soils through their thermal characteristics for use in soil-cement bricks
production is elucidated.
Corrosion Resistance Evaluation of Porous Titanium with Biomimetic Coatings
Authors: Banczek E.P. , de Assis S.L. , de Oliveira Marize Varella , Silva de Medeiros Waléria , Pereira Luiz Carlos , Costa Isolda
Published: March 2009

In this work, porous titanium samples processed by powder metallurgy and coated with
biomimetic coatings, obtained during different periods of immersion in a simulated body fluid
(SBF), were tested for corrosion resistance in a phosphate buffer solution (PBS). Uncoated samples
were also tested for comparison. The corrosion resistance of both types of titanium samples was
evaluated by electrochemical impedance spectroscopy and potentiodynamic polarisation curves. The
electrochemical results indicated the formation of a surface film on the porous Ti samples with
immersion in the SBF solution and this biomimetic film increased their corrosion resistance. This
film helps osteointegration besides increasing corrosion resistance.
α-SiAlON: Development and Machining Test on Gray Cast Iron
Authors: Silva Olivério Moreira Macedo , Nono Maria do Carmo de Andrade , Souza José Vitor C. , Ribeiro M.V.
Published: March 2009

The α-SiAlON ceramic cutting tool insert is developed. Silicon nitride and additives
powders are pressed and sintered in the form of cutting tool inserts at temperature of 1900 oC. The
physics and mechanical properties of the inserts like green density, weight loss, relative density,
hardness and fracture toughness are evaluated. Machining studies are conducted on grey cast iron
workpiece to evaluate the performance of α-SiAlON ceramic cutting tool. In the paper the cutting
tool used in higher speed showed an improvement in the tribological interaction between the cutting
tools and the grey cast iron workpiece resulted in a significant reduction of flank wear and
roughness, because of better accommodation and the presence of the graphite in gray cast iron. The
above results are discussed in terms of their affect at machining parameters on gray cast iron.
Oxidation of Silicon Carbide Ceramics Obtained by Liquid Phase Sintering
Authors: Bondioli M.J. , dos Santos Claudinei , Simba B.G. , Strecker Kurt
Published: March 2009

In this work, silicon carbide ceramics were developed by liquid phase sintering using
AlN-Y2O3 as additive. Two compositions were obtained using SiC powders and different contents
of AlN-Y2O3. The powders were mixed/homogeneizated and subsequently dried and
deagglomerated. Powder mixtures were compacted by cold isostatic pressing. Samples were
sintered at 2080oC, for 1h, under 0.2 MPa-N2 atmosphere. Sintered samples were characterized by
X-Ray diffraction and density. The oxidation behavior was investigated and related to the
densification and additive-content. Samples were submitted to the tests at 1200, 1300 or 1400oC, in
air for 120 hours. Weight gain of the samples is plotted as function of the exposure time, obtaining
the evolution of the oxidation on the surface of the samples. Based on the results, the parabolic
oxidation content (kp) and activation energy were determined. The results indicate that the samples
present parabolic behavior in all conditions. The activation energy results indicate that the
phenomena of diffusion of oxygen ions into the oxide layer and interfacial reactions between oxide
layer and intergranular phase are the responsible for oxidation mechanism.
Selected Values for the Stacking Fault Energy of Face Centered Cubic Metals
Authors: de Campos Marcos Flavio
Published: March 2009

The Stacking fault energy (SFE) is an important parameter for metals and alloys. The
plastic deformation behavior of face centered cubic (FCC) metals and alloys is directly related to
the SFE values. The several methods for determining SFE are critically discussed. The values
reported in the 1960s and early 1970s are, in general, 20-30% overestimated. The node dislocation
method, due to Whelan, overestimates the SFE. The method based on the critical resolved shear
stress is not reliable. The most accurate method is the direct observation of dissociated partials by
weak beam in TEM or using HREM (High resolution electron microscopy). Indirect methods based
in X-Ray Diffraction and texture may provide reasonable estimates since reliable SFE values of
reference metals are available. Selected SFE values for Ni, Cu, Ag, Cu and Al are presented.
Development of Y-TZP Pre-Sintered Blocks for CAD-CAM Machining of Dental Prostheses
Authors: Sasahara Roberta M.C. , Yoshimura H.N. , Fredericci Cátia , Calasans Alberto , Cesar Paulo Francisco , Molisani André Luiz
Published: March 2009

The aim of this work was to establish a route to produce pre-sintered blocks of Y-TZP
(yttria stabilized tetragonal zirconia polycrystal) suitable to be machined in a commercial CADCAM
system, used to manufacture crowns and bridge frameworks for dental applications. Two
commercial Y-TZP powders were investigated. The powders were pressed with different
compaction pressures (40 to 500 MPa) and pre-sintered at temperature ranging from 900 to 1100°C.
Vickers hardness, biaxial flexural strength, and linear shrinkage could be correlated to the relative
density of pre-sintered samples. Using an empirical equation, pre-sintered blocks with a pre-defined
density could be prepared. The blocks withstood the machining in a CAD-CAM system, and the
machined and sintered crowns presented good adaptation.
Hydrogen Production by Ethanol Steam Reforming Over Cu and Ni Catalysts Supported on ZrO2 and Al2O3 Microspheres
Authors: Bergamaschi V.S. , Carvalho F.M.S.
Published: March 2009

Ethanol reforming process to produce hydrogen rich-gas stream is performed using
Cu/Ni catalyst supported on zirconia and alumina microspheres prepared by hydrolysis method.
Theses catalysts were tested in a fixed-bed reactor system employing steam reforming of ethanol.
The operating temperature was 550°C and water/ethanol feed ratio 3/1. Although all catalysts were
very active for ethanol conversion and very selective towards the desired products, but that one
supported on zirconia microspheres was produced slightly better results. The data reveal high
activity of the Cu/Ni/ZrO2 catalyst for ethanol steam reforming and presented a good selectivity for
H2.
Hydrodynamic Characteristics of Free Rise of Light Spheres and Bubbles in Newtonian and Non-Newtonian Liquids
Authors: Melo F.R.G. , Barrozo Marcos A.S. , Ataíde Carlos Henrique
Published: March 2009

Some authors showed that the results obtained for the movement of particle fall in liquids
could not be extended to describe the rising of light particles with the same diameter in the same
difference of density conditions, especially in the region of higher Reynolds number. The main
objective of this study was the investigation of the dynamic behavior of light spheres and of gas
bubbles isolated in stagnant liquids. The experimental data of the rising of light spheres and bubbles
were obtained with photographic techniques and a stroboscope. The obtained results showed that
there were significant differences between the behavior of the ascending gas bubbles and the solid
particles in free fall.
Numerical Assessment of Optimal One-Chamber Perforated Mufflers by Using GA Method
Authors: Chiu Min Chie , Chang Ying Chun , Yeh Long Jyi
Published: March 2009

Research on new techniques of perforated silencers has been addressed; however, the research work
in shape optimization for a volume-constrained silencer requested upon the demands of operation and
maintenance inside a constrained machine room is rare. Therefore, the main purpose of this paper is
not only to analyze the sound transmission loss of a one-chamber perforated muffler but also to
optimize the best design shape under space-constrained conditions. In this paper, both the generalized
decoupling technique and plane wave theory are used. The four-pole system matrix used to evaluate
acoustic performance is also deduced in conjunction with a genetic algorithm (GA); moreover,
numerical cases of sound elimination with respect to pure tones (150, 550, 950 Hz) are fully
discussed. Before GA operation can be carried out, the accuracy of the mathematical model has to be
checked using Crocker’s experimental data. The results reveal that the maximum value of sound
transmission loss (STL) can be optimally and precisely achieved at the desired frequencies.
Consequently, the approach used for the optimal design of the one-chamber perforated mufflers is
indeed easy and quite effective.
Precision Control of a Piezo-Actuate System Using Fuzzy Sliding-Mode Control with Feedforward Predictor-Based Compensation
Authors: Liang Jin Wei , Chen Hung Yi , Chiang Shy Yaw
Published: March 2009

The fuzzy sliding-mode control strategy is used to tackle tracking problem of a
piezo-actuated stage in this paper. The piezo-actuated system is composed of the piezoelectric
actuator and a positioning mechanism. Due to hysteretic nonlinearity of the piezoelectric actuator, the
tracking accuracy of the system is limited. To compensate for this nonlinearity, a feedback fuzzy
sliding-mode control augmented with a predictor-based feedforward compensator is proposed. The
controller, denoted as the feedforward-feedback fuzzy sliding-mode controller (FF-FSMC), can be
applied to eliminate tracking error caused by the hysteretic characteristics. Experimental results on
different types of reference inputs indicate that the proposed control schemes may suppress the
tracking error of the piezo-actuated system effectively.
The Influence of H2O on Iron Oxidation at 600°C: A Microstructural Study
Authors: Jonsson Torbjorn , Pujilaksono B. , Fuchs A. , Svensson Jan Erik , Johansson Lars Gunnar , Halvarsson Mats
Published: March 2009

The oxidation of iron in dry O2 and in wet O2 (40% H2O) has been studied at 600°C. The
oxide microstructure was investigated by SEM/EDX, FIB and XRD. Iron forms a layered scale in
dry and wet oxygen at 600°C. The scale consists of a top hematite layer, a middle magnetite layer
and a wüstite layer close to the scale metal interface. All three layers grow with time, but with
different growth rates, the overall growth being approximately parabolic. The presence of water
vapour increases the rate of oxidation and affects the evolution of the oxide microstructure. The
higher rate of oxidation in the presence of water vapour is due to an increased growth rate of the
magnetite layer and, especially, of the hematite layer, while the growth of the wüstite layer is not
affected. It is suggested that water vapour influences grain boundary transport in the hematite layer.
Thermal Effects of Continuous Laser Treatment on Ti-6 Al(wt%)-4V(wt%) Titanium Alloy
Authors: Puerta Velásquez J.D. , Lavisse L. , Kneip J.C. , Andrzejewski H. , Chevrier P. , Bolle Bernard , Tidu Albert , Matteï S.
Published: March 2009

A titanium alloy Ti-6 Al(wt%)-4V(wt%) was treated in air by Nd:YAG laser radiation
(wavelength of 1.064 %m) in continuous mode. Targets were irradiated globally with different
levels of energy (accumulated fluence) at constant power. Different focal lengths and beam
displacement velocities were used.
Cross section microstructural observations were carried out by scanning electron microscopy.
Backscattered electron imaging reveals microstructural modifications in samples. A structural phase
transformation of beta (bcc) to alpha prime (hcp) phase was observed. The depth of the transformed
zone observed by phase transformation is dependent on the treatment parameters. Conformity
between microstructural observations and the treatment parameters is discussed with reference to
thermal simulations.
Void Formation in Growing Oxide Scales with Schottky Defects and P-Type Conduction
Authors: Maruyama Toshio , Akiba Kojiro , Ueda Mitsutoshi , Kawamura Kenichi
Published: March 2009

A quantitative elucidation of the void formation in a growing scale with Schottky defects
and p-type conduction during high temperature oxidation of metals. The evaluation of the
divergence of ionic fluxes indicates that
(1) Voids form in the scale preferentially in the vicinity of the metal/scale interface,
(2) The volume of voids increases in a parabolic manner,
(3) The volume fraction of voids and the scale is independent of time.
The comparison between the calculation and the experimentally observed scale microstructure of
NiO and CoO confirmed well the validity of the prediction.
Oxidation and Nitridation of Pure Chromium at Elevated Temperature in Synthetic Air – Effect of Silicon Addition
Authors: Royer Laurent , Mathieu Stéphane , Liebaut Christophe , Steinmetz Pierre
Published: March 2009

The oxidation and nitridation of pure chromium and of chromium alloys containing 0.5 to
5at% silicon was investigated at 1300°C in several atmospheres. Global methods like
thermogravimetry were associated to thickness measurements and microstructural characterisation
to evaluate oxidation mechanisms. The contribution of nitridation to weight gain during high
temperature exposure is discussed, examining nitride volume fraction. Experiments demonstrate
that the presence of nitrogen in the substrate is always consecutive to a breakdown of the oxide
layer and does not result from diffusion through the Cr2O3 layer. Silicon, when present in chromium
solid solution, slows down the oxidation kinetics and limits the progression of nitrogen in the
chromium lattice and at grain boundaries. The absence of the Cr2N layer beneath the metal/oxide
interface does not benefit to the adherence of the oxide scale. Oxidation of silicon in chromium
leads to the formation of discontinuous particles of SiO2 at the metal/oxide interface, at the grain
boundaries and dispersed in the bulk in the alloy sub-surface.
A Prototype Software Tool for Life Time Assessment of Thermal Barrier Coating Systems
Authors: Renusch Daniel , Schütze Michael
Published: March 2009

The modeling equations used for spallation prediction are becoming increasingly more
sophisticated due to the consideration of a wider range of thermal and thermo-mechanical loading
conditions. Consequently, a software application would make such life time models more practical
and may become a desired tool that both academic and applied researchers may want to use. As a
starting point for further development a prototype software has been developed based on a simple
phenomenological spallation analysis model. This software features a Windows based graphical
user interface and works with other Windows applications, such as, Power Point, Excel or Origin.
The software analyzes laboratory spallation life time data acquired from isothermal, thermal cyclic
and/or burner rig testing and provides confidence limits and accuracy assessment of the analysis
model. It further calculates the life time for a given bond coat temperature, temperature gradient
across the coating, and thermal cycle frequency.
Corrosion of T91 Steel in LBE: Contribution to the Study of the Pb–Bi–O–Fe–Hg System - Thermodynamic Description of PbO–Fe2O3
Authors: Diop Ibra , David N. , Fiorani J.M. , Podor Renaud , Vilasi Michel
Published: March 2009

The knowledge of the quinary Pb–Bi–O–Fe–Hg is necessary for understanding the
degradation mechanisms of the T91 steel used as structural material in future ADS nuclear reactors.
In this device, the steel will be in direct contact with the liquid spallation target (which is
constituted by lead or lead-bismuth eutectic) surrounded by a reduced oxygen pressure atmosphere.
In the present work, the characterization of the pseudo-binary PbO–Fe2O3 cut has been performed.
In order to complete the available data in the literature, some experimental investigations by DTA,
isothermal annealing, SEM and EPMA have been done. These results have allowed proposing a
thermodynamic assessment using the Calphad method by the ThermoCalc software.
Influence of Al on the High Temperature Corrosion Behaviour of Inconel 617 in VHTR Primary Coolant Atmosphere
Authors: Chapovaloff Jerome , Girardin Gouenou , Kaczorowski Damien , Wolski Krzysztof , Pijolat Michèle
Published: March 2009

Due to the specific in service VHTR conditions, the corrosion behaviour of Inconel 617,
candidate alloy for the IHX design, has been investigated at elevated temperatures in representative
helium containing impurities (CO, H2O, H2 and CH4) in the range of 'bar. The role of Al in the
corrosion behaviour of IN617 is investigated using Ni-22Cr-9Mo base model alloys containing
different Al levels (from 0 to 2wt.%).
Overview of Coating and Compatibility Research for Fusion Energy in the U.S.
Authors: Pint Bruce A.
Published: March 2009

Planning for a U.S. test blanket module to operate in the internationally-sponsored ITER
reactor has focused attention on the many coating and compatibility issues that will need to be
solved before fusion energy moves from concept to commercial reality. Examples are given for (1)
a dual-layer, electrically-resistant coating as a potential solution to reduce the
magnetohydrodynamic pressure drop with liquid Li and (2) materials compatibility issues with
eutectic Pb-Li for conventional alloys and SiC/SiC composites. Because of the reduced activity of
Li in Pb-Li, a wider range of functional materials can be considered in this system. Nevertheless, an
Al2O3 scale on FeCrAl was transformed to LiAlO2
after exposure to Pb-Li at 800°C.
Enhanced Internal Oxidation as Reason for Breakdown of Protective Chromia Scales on FeCr-Alloys in Water Vapour Containing Gases
Authors: Essuman E. , Meier Gerald H. , Zurek J. , Hänsel Michael , Singheiser Lorenz , Quadakkers W.Joe
Published: March 2009

The oxidation behaviour of binary Fe-Cr alloys containing 10 and 20 mass % Cr,
respectively, was studied in Ar-20%O2, Ar-7%H2O and in Ar-4%H2-7%H2O at temperatures
between 800 and 1050°C. Thermogravimetric analyses in combination with analytical studies using
SEM/EDX and Raman Spectroscopy revealed, that in atmospheres in which water vapor is the
source of oxygen, Cr exhibits a higher tendency to become internally oxidized than in the Ar-O2
gas. Contrary to previous studies which showed the presence of water vapor to affect transport
processes in the surface oxide scale, the present results reveal that the presence of water vapor also
affects the transport processes in the alloy. The enhanced internal oxidation, which is likely the
result of water vapor increasing the solubility and/or the diffusivity of oxygen in the alloy, explains
the frequently observed effect that Fe(Ni)Cr alloys with intermediate Cr contents (e.g. 10-20%,
depending on temperature) exhibit protective oxidation in dry gases but breakaway type oxidation
in steam. The temperature dependence of the change from protective to non-protective behaviour in
Ar-H2O differs quantitatively, but not qualitatively from that in Ar-O2.
Cyclic Oxidation of Two FeCrAlRE Foils at 1100 °C - The Influence of the Concentration of Minor Alloying Elements on Scale Microstructure
Authors: Liu Fang , Götlind Helena , Canovic Sead , Lai Hai Ping , Westlinder Jörgen , Rosberg Andreas , Svensson Jan Erik , Johansson Lars Gunnar , Halvarsson Mats
Published: March 2009

Two FeCrAlRE alloys, a commercial, 0C404, and a model alloy in the form of thin foils,
with different Mn, Nb, Mo and Ti concentrations were subjected to cyclic oxidation in lab air at
1100°C. The oxidized samples were studied by gravimetry, Grazing-Incidence X-ray Diffraction
(GI-XRD), Scanning Transmission Electron Microscopy (STEM), and Energy Dispersive X-ray
(EDX) analysis. The two FeCrAl alloys exhibit different oxidation kinetics; however, both alloys
have the same weight gain after 500 hours exposure. During the early stages the scale consists
mainly of α-Al2O3 together with some oxide particles containing Mn, Al, Fe and Cr formed on the
alloys. After 500 hours the 0C404 scale locally also consists of larger polycrystalline regions of
Mn-Cr-Al spinel. In addition, Si-rich oxide, chromia and Al-Cr oxide could be observed at the
metal/oxide interface.
A Model for Transitions in Oxidation Regimes of ZrB2
Authors: Parthasarathy T.A. , Rapp Robert A. , Opeka Mark , Kerans Ronald J.
Published: March 2009

A mechanistic model that interprets the transition in oxidation behavior of zirconium
diboride as the temperature is varied from 600°C to 2500°C is presented. Available thermodynamic
data and literature data for vapor pressures, oxygen permeability in boria, and viscosity of boria
were used to evaluate the model. Three regimes and the temperatures of transition between them
were identified. In the intermediate temperature regime, viz., 1000°C to 1800°C, good
correspondence was obtained between theory and experiments for weight gain, recession, and scale
thickness as functions of temperature and oxygen partial pressure. In this regime, the rate-limiting
step is the diffusion of dissolved oxygen through a film of liquid boria in capillaries at the base of
the oxidation product. At lower temperatures, an external boria scale forms, but it was not found to
contribute significantly to oxidation resistance. Comparison with literature data on recession is very
good, but weight gain is predicted to be higher than experimentally observed unless flow of viscous
boria is included. At higher temperatures, the boria is lost by evaporation, and the oxidation rate is
limited by diffusion of molecular oxygen through the capillaries between nearly columnar blocks of
the oxide MO2.; this regime is soon followed by a rapid acceleration of recession due to
vaporization of the oxide MO2 itself.
The Effect of Water Vapour and Sulphur on Corrosion Mechanisms of Steels
Authors: Tuurna Satu , Yli-Olli Sanni , Heikinheimo Liisa
Published: March 2009

It is well known that water vapour accelerates oxidation; however different gas
conditions and material compositions affect the mechanism. The paper addresses this issue from
two different application areas; biomass and kraft recovery boilers. In these applications water
vapour and sulphur are simultaneously affecting the corrosion mechanism, though the mechanisms
are different.
Low-alloyed steels were exposed to an atmosphere containing different amounts of water vapour at
temperatures of 420, 550 and 600°C. Under oxidising conditions increasing water content generally
accelerates oxidation. However, presence of SO2 in moist atmosphere retards oxidation at high
temperatures. The phenomenon is seen at low temperatures with higher chromium contents.
Stainless steel 304L was tested in an atmosphere containing hydrogen sulphide and carbon
monoxide with and without water vapour at a temperature of 440°C to simulate elevated kraft
recovery boiler furnace conditions. The tests showed that water vapour in the test atmosphere
produces a protective spinel oxide on the metal surface. In tests without water vapour, the initial
scales at metal surface were different sulphur compounds and intensive sulphidation occurred. The
effect of water vapour on the sulphidation mechanism is addressed in the paper through the
described tests and thermodynamic modelling.
Effects of Microstructural Arrangement on Hot Corrosion Resistance of a Pb-Sb Alloy for Battery Grids
Authors: Osório Wislei R.R. , Aoki Claudia S. C. , Garcia Amauri
Published: March 2009

It is well known that the solution characteristics, such as pH and temperature may affect
the corrosion mechanism and the corrosion behavior. Lead acid batteries manufacturers have
provided modifications into the grid project in order to decrease battery grid weight as well as to
reduce the production costs, and to increase the battery life-time cycle and the corrosion-resistance.
The performance of lead-acid batteries in automotive applications can significantly be affected by
temperature variation. The aim of this study was to evaluate the effects of the microstructural
morphology of a Pb-6.6wt%Sb alloy under conditions of hot corrosion. A water-cooled
unidirectional solidification system was used to obtain coarse and fine dendritic microstructures.
Electrochemical impedance spectroscopy (EIS) diagrams, potentiodynamic polarization curves and
an equivalent circuit analysis were used to evaluate the corrosion behavior of fine and coarse
dendritic samples in a 0.5M H2SO4 solution in three different working temperatures. It was found
that independently of the working temperature, samples with finer dendritic microstructures provide
better corrosion resistance than coarser ones, which is an indication that the former microstructural
pattern may provide a higher battery life-time in severe temperatures than a coarser one.
Nanocrystal Non-Volatile Memory Devices
Authors: Horváth Zs.J. , Basa P.
Published: March 2009

The physical background and present status of the application of metal-insulator-silicon structures with semiconductor nanocrystals embedded in the insulator layer for memory purposes is breafly summarized.
Synthesis and Characterization of Cerium Oxide (CeO2) Nanoparticles
Authors: Benmouhoub C. , Kadri A. , Benbrahim N. , Hadji S.
Published: March 2009

Nanoparticles of cerium oxide (CeO2) are synthesized with cerium (III) nitrates (Ce(NO3)3, 6H2O) by precipitation method in ammonium hydroxyl solution (NH4OH).
The influence of several parameters such as nature of the solvent, synthesizing temperature and the calcination on the crystallite size is studied by XRD, TEM and BET methods.
The results show that both calcinations and synthesizing temperature affect the particles size. Also, the nature of solvent has a great effect on the morphology of CeO2 nanoparticles.
Sol-Gel Synthesis of SiO2-TiO2 Film as Antireflection Coating on Silicon for Photovoltaic Application
Authors: Kermadi S. , Agoudjil N. , Sali Samira , Tala-Ighil R. , Boumaour M.
Published: March 2009

Application of thin films of SiO2 and TiO2 using the sol-gel process were utilized as antireflection coating on monocrystalline silicon wafers. The aim of this study is to validate this process as a procedure to prepare antireflective films for monocrystalline silicon by dip-coating. The coating was carried out by dip-coating process using tetraethoxysilane (TEOS) as precursor for SiO2 and titanium isopropoxide (TIPT) as precursor for TiO2. In order to study the influence of the thickness on the reflectance and the optical parameters, several coatings with different thickness were deposited onto silicon wafers. The refractive index and the thickness were adjusted by controlling the number of dipping. The refractive index increases from 2.10 up to 2.22 by increasing the film thickness from 36 to 137 nm. It was found that the sample coated with two layers exhibits a lower reflection (1.86 % at λ = 602 nm). This result was improved by a single sub-layer of SiO2 (36.75 nm) to reach 1.08 % at λ = 674 nm). Furthermore, the low values of the extinction coefficient (k) (approach to Zero at λ = 632.8 nm) indicate that TiO2 and SiO2 films deposited by sol-gel method can be used as ARC for Si solar cells.
Exothermal Behavior during the Hydration of the PCCP+DCPA System Cement
Authors: Wang Xiu Peng , Ye Jian Dong
Published: March 2009

Exothermal behavior is always present during the hydration of cements. The biocompatibility and curing effect of a bone cement is in close relationship with its exothermal behavior. The exothermal behavior in the hydration process of the partially crystallized calcium phosphate (PCCP)+dicalcium phosphate anhydrate (DCPA) system cement was studied in this article. The results show that with the decrease of the particle size of DCPA, the heat release rate was greatly increased; whereas, with the decrease of the particle size of PCCP, the heat release rate was not obviously altered. The heat release in the hydration process of the PCCP+DCPA system cement was only 137 J/g, which was quite smaller than that of the tetracalcium phosphate (TTCP)+dicalcium phosphate dihydrate (DPCD) system cement, and the temperature increase was very small for this cement.
Study of Electrospun PLLACL Nanofibrous Mats for Drug Delivery System
Authors: Liu Shui Ping , Li Xiao Qiang , Su Yan , Tan Lian Jiang , Zhang Yu , Chen Yan Mo
Published: March 2009

In the present study an innovative tissue engineering scaffold was developed which can be used on wound dressing with a controllable drug-releasing capability. By coaxial electrospinning a coaxial nanofibrous mats were obtained which was made from Poly(L-lactid-co-ε-caprolactone) (PLLACL) and Tetracycline Hydrochloride (TCH), with P(LLA-CL) as the shell and TCH as the core. The TCH release behavior of the coaxial nanofibrous mats was measured by ultraviolet-visible (UV-vis) spectroscopy in vitro environment of 37°C for a maximum 180 hours. To compare with the method of mix electrospinning, TCH without any other material could encapsulated in P(LLA-CL) nanofibers very well and released for a long time.
Osteogenesis of Porous Bioceramics Scaffolds Consisted of Hydroxyapatite Spherules after Implanted in Different Non-Osseous Sites
Authors: Yuan Yu , Huang Peng , Peng Qian , Zhang Cong , Weng Jie
Published: March 2009

The interconnected porous scaffolds are crucial to support the attachment, differentiation, proliferation of cells so to construct 3-dimensional (3-D) tissues. Up to now, there are several approaches to prepare porous scaffolds. In our experiments, we designed a novel porous bioceramic scaffold, called the hydroxyapatite (HA) spherule scaffold, by accumulating HA spherules in an HA porous tube to establish an interconnected porous structure which can be reconstructed exactly. The porous HA tube was manufactured by polymer sponge template while HA spherules were prepared by sol-gel process. In the animal experiment, the HA spherule scaffolds were implanted at 2 different non-osseous sites such as muscle and abdominal cavity in dogs. The new bone growth was investigated after six months. The preliminary results demonstrated that the proliferation of osteocytes on the scaffolds in muscle was obviously better than in abdominal cavity, and about ten times more blood vessels (BVs) were appeared in the former site than those in the latter site. This study presents an alternative way to reveal the relationship between the porous structure of scaffolds and ectopia bone growth because the interconnection and porosity can be controlled easily by the size and porosity of HA spherules.
Characterization of an Insoluble Collagen Sponge and the Potential for Tissue Engineering Scaffold
Authors: Zhang Ling , Zhang Yan , Jiang Bo , Fan Hong Song , Zhang Xing Dong
Published: March 2009

Collagen has been widely used in biomedical field, such as scaffolds for tissue engineering. However, the rapidly biodegradation and weak mechanical strength of collagen limited its application. In this study, an insoluble collagen extracted from cattle hide was designed as scaffold to act as a three-dimensional substrate for tissue engineering. The received insoluble collagen sponge was analyzed by scanning electron microscopy, infrared spectroscopy, mechanical testing and thermogravimetric-differential thermal analysis. In addition, the degradation was performed in vitro using collagenase. The results showed that the insoluble collagen had the same triple helical domain as acid-soluble collagen, while the compression strength was greatly improved and the degradation rate was reduced. The insoluble collagen sponge with good stability should be promising in tissue engineering scaffold applications.