bluuebunny/crossref_metadata_2025 huggingface dataset:
2CaO･SiO2-CaO･ZrO2 Thermal Barrier Coating Formed by Plasma Spray Process
Authors: Mifune Noriyuki , Harada Yoshio
Published: March 2009

The applicability of 2CaO·SiO2-CaO·ZrO2 ceramic coatings as thermal barrier coatings (TBCs) was investigated. Coatings consisting of various ratios of 2CaO·SiO2-CaO·ZrO2 bond-coated with NiCrAlY were prepared using the plasma spray process. The structure of the coatings was characterized by scanning electron microscopy and X-ray diffraction analysis. The resistance of the coatings to thermal shock was evaluated with acoustic emission techniques under a thermal cycle from 1273 K to room temperature, and the hot corrosion resistance of the coatings was investigated with V2O5 and Na2SO4 at 1273 K for 3 h. The 2CaO·SiO2-10~30mass%CaO·ZrO2 coatings had excellent thermal shock resistance, because the coatings contained a vertical micro-crack in a single flattened ceramic particle. These coatings possessed excellent corrosion protection preventing direct contact between the corrosive ashes and a NiCrAlY bond coating. The CaO in the coating reacted with vanadium compounds and inhibited the penetration of corrosive ashes to the bond coating. The developed 2CaO·SiO2-20mass%CaO·ZrO2 thermal barrier coating on stationary vanes was evaluated in an actual gas turbine. The ceramic coating did not separate from the bond coating and reacted with SOx in combustion gas to produce a stable sulfate (CaSO4), which fixed in the coating. The TBC effectively protected the metal substrate of the vanes in practical operating condition for 25,000 h.
In Situ Observation of Failure Behavior for Plasma Sprayed Thermal Barrier Coating Systems under Static Loadings
Authors: Takahashi Satoru , Yoshiba Masayuki , Kawamura Raito , Harada Yoshio
Published: March 2009

In situ observation of the mechanical failure behavior was conducted for different kinds of the plasma sprayed thermal barrier coating (TBC) systems by means of an optical microscopy under the static loadings at room and elevated temperatures; as the fundamental aspect, in order to clarify the thermomechanical failure mechanism of TBC system in connection with various coating characteristics. Mechanical tensile or compressive loading was applied progressively to the TBC specimen by an axial loading mode. It was found that the failure behavior of TBC system depends strongly on the testing temperature under both the tensile and compressive loadings. At the elevated temperature which is higher than the ductile-brittle transition temperature (DBTT) of metallic bond-coat (BC), in particular, the ceramic top-coat (TC) spallation can be prevented by virtue of the stress relief induced by the enhanced plastic flow in the BC layer. At the room temperature which is lower than the DBTT of BC, on the contrary, the TC spalling was inevitably induced, but the initiation site of TC spalling is closely related with the magnitude of local plastic deformation in the alloy substrate. Furthermore, an influence of thermally grown oxides (TGO) layer developed at the TC / BC interface on the crack initiation and propagation behavior was investigated in some detail.
Effect of Laser Fusing on Hot Corrosion Resistance of Nickel Based Self Fluxing Alloy Coating
Authors: Li Yu , Nishio Kazumasa , Katoh Mitsuaki , Yamaguchi Tomiko , Okamine Shinji
Published: March 2009

The thermal sprayed coatings are widely used in waste incineration boilers and fossil fuel-fired boilers. However, the defects, such as porosity, cracks and unmelted particles, in these coatings are detrimental to corrosion performance. In this study, the nickel based self fluxing alloy coating was fused by YAG laser to improve hot corrosion resistance of the coating. Under appropriate laser parameters, the nonporous, crack-free coating was produced. Hot corrosion test, conducted in the presence of a mixed salt of Na2SO4/NaCl/KCl at 550Гshowed that the modified coating exhibited excellent corrosion resistance compared with the as sprayed and gas fused coatings.
Transition from External to Internal Oxidation of Single Phase Binary Alloys
Authors: He Ye Dong , Ma Jing , Li Zheng Wei , Gao Wei
Published: March 2009

It is shown from the oxidation results that, for Fe-Cr, Ni-Cr, Co-Cr binary alloys with and without internal Cr2O3 precipitations after exposure, continuous external Cr2O3 scales formed on their surfaces, especially at the initial stage. It is therefore suggested that the transitions of oxidation for these alloys take place from externally to internally. There are two types of transitions for alloys: (1) the transition from temporary external oxidation to internal oxidation; and (2) the transition from permanent external oxidation to internal oxidation. The thermodynamic conditions for these transitions have been analyzed, and the criterion for prediction of the minimum solute concentration of a binary solid solution alloy required for the second transition has been derived. It is also suggested that the external oxide scale is an important factor to determine the formation of pure solvent metal nodules on the surfaces.
Hardness of Oxide Scales on Fe-Si Alloys at Room- and High-Temperatures
Authors: Amano Takumi , Okazaki M. , Takezawa Y. , Shiino A. , Takeda Mikako , Onishi Takashi , Seto Kazuhiro , Ohkubo A. , Shishido Toetsu
Published: March 2009

Hardness of oxide scales on Fe-(0, 0.5, 1.5, 3.0)Si alloys was studied at room temperature after
oxidation at 1273 K for 18 ks in oxygen, and at 1073 and 1273 K for 180 and 1080 ks in dry air, by
micro-Vickers hardness measurements. After oxidation at 1273 K for 18 ks, high-temperature hardness of
oxide scales on Fe-(0, 1.5, 3.0)Si alloys was also measured at 1273 K. Oxide scales on Fe-Si alloys were
mainly Fe2O3, Fe3O4, FeO and Fe2SiO4. Hardness of Fe2O3, Fe3O4 and FeO on Fe was 6.7, 4.0 and 3.5 (GPa),
respectively, and hardness of Fe2O3 on Fe-Si alloys slightly increased with increasing silicon content at room
temperature. At 1273 K, hardness of Fe3O4 and FeO on Fe was 0.08 and 0.05 (GPa), respectively, and
hardness of Fe2O3 on Fe-1.5Si alloy was 0.32 (GPa), and that of Fe2O3 and Fe2SiO4 on Fe-3.0Si alloy was
0.53 and 0.63 (GPa), respectively.
Influence of Chlorine, Sulphur and Water Vapor on High Temperature Corrosion of Fe, Cr, Ni Alloys for Waste Incinerators
Authors: Moulin Gérard , Weulersse Katia , Favergeon Jérôme
Published: March 2009

The behavior of three different materials with respect to their Fe, Cr, Ni contents have been studied between 450°C and 700°C, in waste incinerators combustion conditions, where it occurs a main influence of chlorine, sulfur and water vapor. This works analyzes the behavior of these materials which depends on their capability to form melted compounds and on the nature of these melted phases. Also as the corrosion mechanism is influenced by the presence or missing of any corrosive species, the study focalizes on the specific influence of SO2 and alkaline chorine. Effect of additive ashes on the corrosion behavior of tested materials is also studied. The mechanism of corrosion in waste incinerators is supported by thermodynamic calculations performed with the “Thermocalc” software.
The Importance of Residual Stresses in Microelectronic Products and Materials
Authors: Müller Wolfgang H.
Published: March 2009

In this paper we will discuss the impact of residual stresses on the reliability of microelectronic
components and the materials used therein. The following issues will be particularly emphasized:
First, the tendency toward delamination and subsequent cracking along interfaces, such as between
silicon dies, organic substrates, glues, and underfill material; second, the fatigue of electrolytically
deposited copper vias within the substrate and FR4 board material; third, the accumulation of
irreversibly accumulated plastic (creep) strain in lead containing as well as leadfree solders; the microstructural
change observed during thermo-mechanical use within the bulk as well as at the interface of
solder interconnects. We will present state-of-the-art numerical techniques that allow to quantify the
development of stresses and strains within the aforementioned materials, mostly by finite element
analysis, as well as the coupling between local stresses and diffusion processes, which is theoretically
based on phase field models. Further emphasis is put on proper knowledge and determination of the
inherent material parameters and how theoretical predictions can be linked to and validated by experimental
observations and facts.
SALSA: Advances in Residual Stress Measurement at ILL
Authors: Pirling Thilo , Bruno Giovanni , Withers Philip J.
Published: March 2009

SALSA (Strain Analyser for Large Scale engineering Applications) is a novel
instrument for strain imaging at the high flux neutron reactor of the Institut Max von Laue – Paul
Langevin (ILL) in Grenoble, France. It is the first of its kind that uses a precise robotic sample stage
for sample manipulation. In addition to standard xyz-translation it provides tilts up to ±30° about
any horizontal axis. Its load capacity is more than 500 kg and samples up to 1.5 m in length can be
scanned with high accuracy. Thanks to a double focusing monochromator and supermirror guide
count times are very short. A broad wavelength range, variable beam optics, including radial
focusing collimators for high lateral resolution, make it a very flexible instrument for a large variety
of strain imaging applications in small and large specimens. The instrument has been commissioned
in 2005 and is open for access by a peer review proposal system and as well by industry. The paper
describes the important aspects of the instrument and results from the first experiments.
Micro Diffraction Imaging of Bulk Polycrystalline Materials
Authors: Wroblewski Thomas , Bjeoumikhov A. , Hasse Bernd
Published: March 2009

X-ray diffraction imaging applies an array of parallel capillaries in front of a position
sensitive detector. Conventional micro channel plates of a few millimetre thickness have
successfully been used as collimator arrays but require short sample to detector distances to achieve
high spatial resolution. Furthermore, their limited absorption restricts their applications to low
energy X-rays of around 10 keV. Progress in the fabrication of long polycapillaries allows an
increase in the sample to detector distance without decreasing resolution and the use of high X-ray
energies enables bulk investigations in transmission geometry.
Evaluation by Synchrotron Radiation of Shape Factor Effects on Residual Stress in Nitrided Layers
Authors: Goret Vincent , Fabre Agnès , Barrallier Laurent , Vardon Patrick
Published: March 2009

Nitriding is a thermo-chemical treatment to improve fatigue life of steel parts what are exposed to
high cyclic loading on and close to the surface like gears for example. During the nitrogen diffusion,
the precipitation of nitrides and carbides generates residual stresses and increases the superficial
hardness. These residual stresses are function of the conditions of the nitriding process but also
critically depend on the geometry of the steel components. Indeed, the result of the diffusion process
is different for a plane geometry or a curvilinear one. In this present work, the sample is a part of a
gear, composed by two teeth. Between two teeth of gear, the determination of in-depth stress
gradients by classical X-rays diffraction cannot be done with a great accuracy: the spatial resolution
is not sufficient because the irradiated area has the same dimension than the surface curvature of the
component. Furthermore, it is very difficult to take into account the removal of matter that is
required to determine in-depth stress profile because of the particular geometry. The synchrotron
diffraction technique is a well-adapted method to determine such stress gradients in strongly
absorbing materials due to the capability of penetration power of high energy X-rays. The removal
of matter is not required and it is possible to determine an in-depth map of the stress tensor. After
measurements on the ESRF ID15 beam line, stress profile has been calculated without the σ33 equal
to zero hypothesis. The results are as following: compressive residual stresses were found close to
the surface, and the calculated σ33 component of stress tensor is really not equal to zero. This
important result seems to show the geometrical effect on stress state near non-plane surface.
Neutron and X-Ray Diffraction Analysis of Residual Stresses in Cold-Rolled Pearlitic Steel Sheet
Authors: Seefeldt Marc , Walentek Artur , van Houtte Paul , Vrána Miroslav , Lukáš Petr
Published: March 2009

This paper reports about a combined neutron and X-ray diffraction study on the residual
stresses in the ferrite matrix of cold-rolled fully pearlitic steel sheet. Neutron diffraction revealed
compressive residual phase microstresses of about – 500 MPa in rolling direction. However, even in
normal direction there are significant tensile residual microstresses, indicating that the morphology
of the lamellar microstructure cannot be properly described as a “sandwich structure”. Neutron
diffraction was also used during an in-situ tensile test to estimate the microstress level in the
cementite phase. The combination of neutron and X-ray diffraction allows to separate, near the
surface, the residual phase microstresses from the macrostresses. The latter are also important in
rolling direction and imply some risk of undesirable shape changes after forming operations.
Residual Stresses in Laser Beam Welded Butt Joints of the Airframe Aluminium Alloy AA6056
Authors: Staron Peter , Vaidya W.V. , Koçak Mustafa , Homeyer Jens , Hackius J.
Published: March 2009

Residual stresses in CO2 laser beam welded AA6056 Al-sheets of 3.2 and 6.0 mm
thicknesses were studied using neutron and high-energy X-ray diffraction. The influence of the
temper T4 and T6 before welding, the effect of sheet thickness in T6 temper, and the effectiveness
of post-weld heat treatments T6 and T78 for the reduction of residual stresses in the sheets welded
initially in the T4 temper were examined. It was found that tensile longitudinal stresses were
significantly higher when welded in T6 than in T4. With the increase in the sheet thickness from 3.2
to 6.0 mm, the residual stress profile was affected more than the stress level when welded in T6. For
3.2 mm sheet, the post-weld heat treatments T6 and T78 did not lead to a significant reduction in
residual stresses when welded in T4.
A new Approach in Residual Stresses Analysis by Speckle Interferometry
Authors: Maras Afaf , Montay Guillaume , Sicot Olivier , Rouhaud Emmanuelle , François Manuel
Published: March 2009

The knowledge of residual stresses allows a reliable prediction of structure performances evolution,
such as service life [1-3]. In this paper, we develop a new method for residual stresses determination
combining Electronic Speckle Pattern Interferometry (ESPI) with the machining of a groove. The
internal stress field is perturbed as the depth of the groove is increased incrementally. The structure
finds a new equilibrium state generating displacements which are measured using ESPI. This method
was tested on an aluminium alloy AU4G plate treated locally by an ultrasonic shot-peening. The
investigation of the images obtained with the phase shifting technique and fringe patterns, makes it
possible to analyze, simultaneously, the stress profile along two directions: along the depth of the
structure, and along the groove direction.
Residual Stress Analysis in Crankshaft Using the Hole Drilling Method
Authors: Montay Guillaume , Cherouat Abel , Lu Jian
Published: March 2009

The aim of this paper is to determine the incremental residual stress profile in depth of a
complex shape. The authors have adapted the hole drilling method in a crankshaft and more
precisely in the filet area. A new set of calibration coefficients have been determined using
the finite elements method in order to analyse residual stresses in the structure.
Method for Mapping Multi-Axial Residual Stresses in Continuously-Processed Bodies
Authors: DeWald Adrian T. , Hill Michael R.
Published: March 2009

This paper describes a method for extending the capability of the contour method to
allow for the measurement of spatially varying multi-axial residual stresses in prismatic,
continuously-processed bodies. Currently, the contour method is used to determine a 2D map of the
residual stress normal to a plane. This work uses an approach similar to the contour method to
quantify multiple components of eigenstrain in continuously-processed bodies, which are used to
calculate residual stress. The result of the measurement is an estimate of the full residual stress
tensor at every point in the body. The methodology is presented and the accuracy is assessed for a
representative test case using a numerical experiment. Finally, a measurement is performed on a
thick laser peened plate of 316L stainless steel to show that the approach is valid under real
experimental conditions.
Residual Stress Evaluation in TiN Coatings Used for Erosion Protection of Aerospace Components
Authors: Bielawski Mariusz
Published: March 2009

A laser beam profilometry technique was used to investigate residual stress accumulation
during TiN deposition and stress relaxation during post-deposition heat treatment. The test coatings
were reactively sputtered on silicon and steel substrates using a UMS technique. TiN coatings,
deposited at different bias and pressure levels, were evaluated for residual stress and microhardness.
It was found that both the residual stress and the hardness were strongly affected by the coating
deposition conditions. In addition, stress-temperature correlations were obtained by subjecting the
coatings to temperature cycles up to 450°C. Stress-temperature plots revealed that the level of
residual stress relaxation depended on deposition conditions and only coatings deposited at low ion
bombardment could be fully annealed. The role of intrinsic and thermal stresses in the total residual
stress in the coating/substrate system was also discussed.
Residual Stress State at Different Scales in Deep Drawn Cup of Unstable Austenitic Steel
Authors: Berrahmoune M. Reda , Berveiller Sophie , Inal Karim , Patoor Etienne
Published: March 2009

In this study, residual stresses state at different scales in the 301LN unstable austenitic
steel after deep drawing was determined. The first part of the work deals with the characterization
of the martensitic transformation during uniaxial loading. The austenite/martensite content which
was determined by X-Ray Diffraction increases until a maximum of 0.6 for 30% strain. Internal
stress distribution was determined by coupling in-situ tensile tests with sin²ψ method. As soon as
martensite appears, the magnitudes of the internal stresses in this phase were found to be 400 MPa
higher than in the austenite. To establish a relation between the complex loading path effect and the
phase stress state, deep drawing tests were carried out for different drawing ratios. Both
macroscopic tangential residual stresses and residual stresses in the martensite were determined. It
appears that the macroscopic tangential residual stresses are positive and increase with increasing
drawing ratios and the maximum value is located at middle height of the cup. It is about 850MPa
for the Drawing Ratio (DR)=2.00. The tangential residual stresses in the martensite were found to
be positive in the external face and have a same evolution as the macroscopic ones.
Growth Kinetics of Hardened Layers Produced during Nitriding in Ammonia Gas Environments
Authors: Mridha S.
Published: March 2009

In gas nitriding the thickness of the case depth is reported to increase parabolically with processing time and ammonia content in the NH3/H2 gas mixture which consequently increases the thickness of undesirable surface iron-nitride (white layer). In this investigation two commercial grade low alloy steels were nitrided in gas atmospheres containing 10 to 80% ammonia at 4700, 5200 and 5700C for 6 to 96 h. A metallographic technique was used to reveal different zones of the nitrided surface and the thickness of the diffusion zone was recorded using microscope. The growth kinetics of the diffusion layer of these two steels were analyzed and compared with that of 3% chromium (En40B) steel from literature. The results of the investigation conclusively suggest that the growth rate of the nitrided layer for both steels reached to a maximum with the increase of ammonia content in the gas mixture up to an optimum level where the thickness of the white layer is a minimum. However, the growth rates of the nitrided case are different for different steels.
Punch and Counterpunch Design by the Die Expansion Method in Completely Closed Die Forging
Authors: Ibhadode A.O. Akii
Published: March 2009

Design equations based on die expansion are derived for selecting punch and
counterpunch dimensions in completely closed die forging. The method imposes lower limits
on the punch (counterpunch) – container radial clearance and forging height tolerance that
may be specified.
Feature Selection for Tool Condition Monitoring in Turning Processes
Authors: Salgado D. Rodríguez , Cambero I. , Alonso F.J.
Published: March 2009

The aim of the present work is to develop a tool condition monitoring system (TCMS) using sensor fusion and artificial neural networks. Particular attention is paid to the manner in which the most correlated features with tool wear are selected. Experimental results show that the proposed system can reliably detect tool condition in turning operations and is viable for industrial applications. This study leads to the conclusion that the vibration in the feed direction and the motor current signals are best suited for the development of a TCMS than the sound signal, which should be used as an additional signal.
Corrosion Resistance of Nd-Fe-B Magnets Coated with Polypyrrole Films
Authors: Bandeira M.C.E. , Prochnow F.D. , Costa Isolda , Franco César V.
Published: March 2009

Nd-Fe-B magnets present outstanding magnetic properties. However, due to their low
corrosion resistance, their applications are limited to non-corrosive environments. Nowadays,
significant efforts are underway to increase the corrosion resistance of these materials, through
the use of coatings. Herein are presented the results of a study on the corrosion resistance of
Nd-Fe-B magnets coated with polypyrrole (PPY). The electrochemical behavior of coated and
uncoated magnets has been studied by Electrochemical Impedance spectroscopy (EIS) in
synthetic saliva. The results were compared to previous investigations, which were carried out
under similar conditions, in Na2SO4 and NaCl solutions. In sulphate solution, the corrosion
resistance of the PPY-coated magnet was 3 times larger (1600 .cm2) than that of uncoated
magnet (500 .cm2). In NaCl solution, however, the corrosion resistance of coated and
uncoated magnets were very similar (250 .cm2). In synthetic saliva, both the uncoated and
coated magnets presented good corrosion performance (1940 .cm2). Such behavior can be
attributed to the phosphate ions in saliva, which play a role as corrosion inhibitor, producing
phosphating, at least partially, of the magnet surface. The PPY-coated magnets presented a
strong diffusional control from moderate to low frequencies, caused by the polypyrrole film.
The thicker PPY film increased the corrosion resistance of the magnet in synthetic saliva.
Syntheses of the Ni3Ti, NiTi, and NiTi2 Compounds by Mechanical Alloying
Authors: Martins C.B. , Fernandes Bruno Bacci , Ramos Erika Coaglia Trindade , Silva Gilbert , Ramos Alfeu Saraiva
Published: March 2009

The aim of this work is to prepare the Ni3Ti, NiTi, and NiTi2 compounds by
mechanical alloying from elemental Ni-25at.%Ti, Ni-50at.%Ti, and Ni-66.6at.%Ti powder
mixtures. The milling process was carried out in a planetary ball mill under argon atmosphere
using a rotary speed of 200rpm, stainless steel balls (10 and 19 mm diameters) and vials
(225mL), and a ball-to-powder weight ratio of 10:1. Following, the milled powders were heat
treated at 900oC for 1h in order to attain the equilibrium microstructures. The milled powders
were characterized by means of X-ray diffraction (XRD), scanning electron microscopy
(SEM), and microanalysis via EDS. Similar ball milling behavior of Ni-Ti powders was noted
in this work, e.g., a pronounced cold-welding between ductile powders occurred during the
initial milling times. The Ni3Ti, NiTi, and NiTi2 compounds were synthesized after milling
for 30h. Atomic disordering of the NiTi and NiTi2 compounds was achieved, and amorphous
structures were then formed in Ni-50Ti e Ni-66.6Ti powders milled for 60h and 210h,
respectively. Homogeneous matrixes constituted by the Ni3Ti, NiTi, and NiTi2 phases were
formed in Ni-Ti powders after heat treatments at 900oC for 1h. Iron contamination lower than
2 at-% was measured by EDS analysis in heat-treated Ni-Ti alloys.
Composite Materials Based on EN AW-Al Cu4Mg1(A) Aluminum Alloy Reinforced with the Ti(C,N) Ceramic Particles
Authors: Dobrzański Leszek Adam , Włodarczyk-Fligier Anna , Adamiak Marcin
Published: March 2009

Investigations of composite materials based on EN AW-Al Cu4Mg1(A) aluminum
alloy reinforced with the Ti(C,N) particles with various weight ratios of 5, 10, and 15% are
presented.
Powders of the starting materials were mixed in the laboratory vibratory ball mill to
acquire the uniform distribution of reinforcement particles in the matrix material. The
components were initially compacted at cold state in a die with the diameter of ∅ 26 mm in
the laboratory vertical unidirectional press – with a capacity of 350 kN. The obtained P/M
compacts were heated to a temperature of 480÷500°C and finally extruded – with the extrusion
pressure of 500 kN. Bars with a diameter of 8 mm were obtained as the end product.
Based on the microstructural examinations of the obtained composite materials, the
uniform distribution of the reinforcing particles in the aluminum matrix was revealed.
Hardness tests, tensile tests and the ultimate compressive strength tests made it possible
demonstrate that all these properties change along with the reinforcing particles concentration
change.
Gradient Nickel – Alumina Composite Coatings
Authors: Kunioshi Clarice Terui , Correa Olandir Vercino , Ramanathan Lalgudi Venkataraman
Published: March 2009

Particle reinforced metal matrix composite (MMC) coatings have been developed due to property combinations such as increased hardness, high creep/fatigue resistance as well as superior wear and oxidation resistance. MMC coatings can be produced by various techniques, which include powder metallurgy (plasma spray and HVOF processes), liquid metal processes and electrodeposition. This paper presents the development of the electrodeposition process to obtain nickel-alumina composites. The process conditions were optimized and based on these gradient nickel-alumina composites were prepared. Microstructural characterization and hardness determinations were carried out. The effect of process parameters on the amount and distribution of alumina particles as well as morphology of the deposits with and without alumina gradients are presented and discussed.
Ultra High Carbon Steels Obtained by Powder Metallurgy
Authors: Martinez M.A. , Abenojar J. , Mota J.M. , Calabrés R.
Published: March 2009

The objective of the present work is to study the manufacturing process of steels
with high carbon content (1.5–2.1wt%) obtained by powder metallurgy. The reference
material was the Damascus steel, which was employed to manufacture swords named after it
and has been widely known due to its very good mechanical properties. The main reasons of
the success of this product are: the high carbon content of the initial steel and the
thermomechanical treatment (forge and quenching) that ancient iron forgers kept secretly
during centuries. Different carbon contents (2 to3 wt%) were added to the same Fe powder
matrix (ASC 300), and compacted and sintered steels are heat laminated (750°C) with a
reduction of 20%. For 2% carbon content, the result is a steel with yield strength of 450 MPa,
Young’s Modulus of 14.3 GPa and hardness of 109 HV(30).
Analysis of the Behavior of Solid-Liquid Systems Based on the Shape, Size Distribuition and Density of the Solid Particles
Authors: Arouca Fábio de Oliveira , Azevedo C.G. , Oliveira M.H.A. , Damasceno João Jorge Ribeiro
Published: March 2009

The dynamic analysis of behavior of solid particles in porous media such as settling processes are important for the dimensioning increasingly precise of pieces of equipment that promote the solid-liquid separation. Several factors can influence in dynamics of the fall of solid particles into a fluid medium; among them, the shape, distribution of sizes, and particle density. The main objective of this work is to analyze the behavior of solid-solid system based on the shape, size distribution and density of solid particles. The initial settling velocity in batch settling tests and the accommodation of particles in the sediment formed are evaluated for different materials. The gamma-ray attenuation technique was used in the experimental tests. Comparison of results obtained allowed evaluating in an exploratory research the significance of variables involved.
Effect of Operational Parameters in the Droplet Size of a Venturi Scrubber with Multi-Orifice Injection
Authors: Guerra Vádila Giovana , Ribeiro A.P.R.A. , Gonçalves José Antônio Silveira , Coury José Renato
Published: March 2009

The Venturi scrubber is used for removing particulate matter from gaseous
effluents and finds a large application in industry. The size of the droplet is of fundamental
importance to the performance of the equipment. This work aims at studying the effect of
some design parameters, namely liquid flow rate and liquid injection system in the droplet
size and to correlate this with collection efficiency. A laser diffraction technique was used in
order to measure droplet size in situ in a rectangular Venturi scrubber, with liquid injected
through 1mm diameter orifices on the throat walls. Liquid flow rates of 600 and 900 ml/min
and number of orifices varying from 1 to 5 were used in the experiments. The throat gas
velocity was kept at 69.3 m/s. It was found that all these variables significantly affected
droplet size. The results of droplet size were compared with the particle capture (collection)
efficiency measured in the same experimental conditions. It was observed that the collection
efficiency was affected by the liquid atomizing conditions and by the droplet distribution in
the Venturi throat.
Computational Fluid Dynamics Applied to Bradley Hydrocyclones
Authors: Vieira Luiz Gustavo Martins , Damasceno João Jorge Ribeiro , Barrozo Marcos A.S.
Published: March 2009

Hydrocyclones are centrifugal devices employed on the solid-liquid and liquid-liquid
separation. The operation and building of these devices are relatively simple, however the flow
inside them is totally complex and its prediction is very difficult. The fluid moves on all possible
directions (axial, radial and swirl), the effects of turbulence can not negligible and an air core along
the center line of the hydrocyclone can appear when the operational conditions are favorable. For
that reason, the most models that are used to predict the hydrocyclone performance are empirical
and require the collection of the main operational and geometric variables in order to validate them.
This work objectified to apply Computational Fluid Dynamics (CFD) on Bradley Hydrocyclone and
compare the results from this technique to empirical models. The numerical simulation was made in
a computational code called Fluent® that solves the transport equation by finite volume technique.
The turbulence was described by Reynolds Stress Model (RSM) and the liquid-gas interface was
treated by Volume of Fluid Model (VOF). In agreement with the results from the simulation, it was
possible to predict the internal profiles of velocity, pressure, air core, particle trajectories,
efficiencies, pressure drop and underflow-to-throughput ratio.
Preparation and Characterization of Zirconia-Yttria/Zirconia-Magnesia Composites
Authors: Caproni E. , Muccillo R.
Published: March 2009

ZrO2: 3mol% Y2O3 powders were mixed in different proportions to ZrO2: 8 mol%
MgO, pressed and sintered at 1500°C for producing composites with oxygen ion conductivity
better than that of ZrO2: 8 mol% MgO and thermal shock resistance better than that of ZrO2: 3
mol% Y2O3. The electrical conductivity was evaluated by the impedance spectroscopy
technique at 600°C as a function of the partial pressure of oxygen using zirconia-based
oxygen pump and sensor. The thermal shock resistance was studied by room temperature-
1550°C dilatometry on sintered pellets. Moreover the composites were studied by X-ray
diffraction and scanning electron microscopy. All composites are partially stabilized in the
monoclinic-tetragonal phase and the apparent density is higher than 90% of the theoretical
density. The thermal shock behavior of the composites is similar to that of ZrO2:8 mol% MgO
materials used in disposable high temperature oxygen sensors. The electrical response of the
composites at high temperatures is better than the electrical response of ZrO2:8 mol% MgO.
Synthesis and Kinetic Study by Ozawa Method of the Thermal Decomposition of Complexes Ln(thd)3phen
Authors: Lopes Wilton Silva , da Silva Morais Crislene Rodrigues , Souza A.G. de
Published: March 2009

Recently, highly luminescent lanthanide complexes with mixed ligands such as and
β-diketone and two herobiaryl ligands have been synthesized and suggested as promising
light-conversion molecular devices as described by several authors. The synthesis,
luminescence, quantum yields, spectroscopic characteristics, structure, among others
properties of these complexes, including the possibility of production thin film films from
these materials have been discussed, but little is known about their thermal decomposition
kinetics. In this work we report the determination of kinetic parameters of thermal
decomposition of the complexes Gd(thd)3phen and Er(thd)3phen (thd=2,2,6,6-tetramethyl-3,5-
heptanodione; phen=1,10-phenantroline) using the method proposed by Ozawa (1965). The
kinetic parameters obtained for activation energy were: 90 and 87 kJ.mol-1, the values of
frequency factor were: 2.3x107 and 2.0x107 s-1 for Gd(thd)3phen and Er(thd)3phen,
respectively. On the kinetic energy of the complexes, we notice the following order in thermal
stability: Gd(thd)3phen < Er(thd)3phen.
Influence of Sintering on Electrical Properties and Phase Transition of La2Mo2O9
Authors: Rocha R.A. , Muccillo E.N.S.
Published: March 2009

High ionic conductivity ceramics have potential technological applications in chemical sensors, ceramic permeable membranes, oxygen pumps, and solid oxide fuel cells. Recently ionic conductivity values as high as those of doped zirconia solid solutions have been found in a lanthanum molybdate compound. The high ionic conductivity of this compound, La2Mo2O9, is obtained at temperatures above the structural phase transition temperature (~580 °C). In this work the La2Mo2O9 ceramic material was prepared by the polymeric precursor technique and sintered at several dwell temperatures and soaking times to study the effect of sintering conditions on phase transition. It was found that there is a strong dependence of phase transition on the sintering profile. At 950 °C the phase transition is suppressed for short soaking times, whereas it is observed to occur for longer times. Moreover, the relative magnitude of conductivity is also dependent on the sintering conditions. The main conclusion is that the phase transition in La2Mo2O9 is particle sizedependent.
Effect of Thermal Treatment under Oxygen Atmosphere on the Superconducting Properties of RuSr2GdCu2O8
Authors: de Albuquerque Gimenez Juliana Maria , Grandini Carlos Roberto , Góes M.S. , Jurelo A.R. , Dobrzanski R.
Published: March 2009

The discovery of the spatial uniform coexistence of superconductivity and
ferromagnetism in rutheno-cuprates, RuSr2GdCu2O8 (Ru-1212), has spurred an extraordinary
development in the study of the competition between magnetism and superconductivity.
However, several points of their preparation process and characterization that determine their
superconductive behavior are still obscure. The improvement of sample preparation conditions
involves some thermal treatments in inert atmosphere. The first treatment results in the
immediate formation of Sr2GdRuO6. Using the CuO composition as a precursor, we produced
Ru-1212. To turn it metallic and superconductor, besides the previous treatment, a final
sinterization is carried out in oxygen flow for several days. Three Ru-1212 samples were
produced by varying the last sinterization time (two, four, and six days under oxygen flow).
Through measurements of x-ray diffraction, scanning electron microscopy, differential thermal
analysis, magnetic susceptibility and mechanical spectroscopy, it was studied the influence of
the treatments under oxygen atmosphere on the structural and superconducting properties of the
material.
Hardness and Toughness of Aluminum Porcelains Measured by the Indentation Test
Authors: Bragança S.R. , Bergmann C.P.
Published: March 2009

Triaxial porcelains for utilization in electric applications use alumina in its composition
replacing quartz in order to improve mechanical strength. This property is a critical parameter
for the application of this product. As a consequence of that, in this work, it was evaluated the
mechanical strength, analyzing porcelain hardness and toughness by the indentation test, a
fast way for measurement of strength. It was studied the different models used in the
measurement of these parameters found in literature. It was verified which procedures are
better for this type of material, comparing to values of toughness obtained by the method of
Fracture Mechanics using notched samples. It is also presented technical characterization and
photomicrographs of the analyzed samples.
Synthesis and Characterization of Ni-Cu/ZrO2 and Co-Cu/ ZrO2 Catalysts Used for Ethanol Steam Reforming
Authors: Bergamaschi V.S. , Carvalho F.M.S. , Santos W.R. , Rodrigues C.
Published: March 2009

Zirconia has received much attention as catalysts for its high surface area and
acid-base property. The textural and acid-base properties of ZrO2 depend on both, the
synthesis procedure and the calcinations temperature. The aim of the present study is the
preparation and characterization of nickel/cupper/zirconia and cobalt/cupper/zirconia
microspheres using hydrolysis process. This process is based on homogeneous
hydrolysis of droplets of a concentrated ZrO2(NO3)2-urea solution after adding
hexamethyletetramine. Gelation was conduced successfully and the gel spheres were
dried at 80 °C. The dried gel spheres were thermally treated at 550 °C. Characterization
of the samples was performed using X-ray diffraction (XRD), BET nitrogen adsorption,
scanning electron microscopy (SEM), thermogravimetric (TGA) and UV-Vis
spectroscopy. The performance of the microspheres was investigated as catalysts in
steam reforming of ethanol. Theses catalysts exhibit a good selectivity for hydrogen.
Solid Oxide Fuel Cells: Strontium-Doped Lanthanum Manganite Obtained by the Citrate Technique
Authors: Chiba Rubens , Vargas Reinaldo Azevedo , Andreoli Marco , Seo Emília Satoshi Miyamaru
Published: March 2009

Nowadays, the La1-XSrXMnO3 (LSM) is one of the most common cathodic
materials used in the solid oxide fuel cells (SOFCs). The dopant strontium increases the
electronic conductivity of the material, besides presents an excellent electrochemical
performance, relatively good chemical and thermal stability and compatibility with solid
electrolyte of ZrO2/Y2O3 (YSZ). In this work, a contribution to the study of synthesis of LSM
is presented with strontium concentration of 50 mol % by the citrate technique. The powders
have been characterized for various techniques, as gas absorption and adsorption, X-ray
fluorescence spectroscopy, laser scattering granulometry, gas helium picnometry, scanning
electron microscopy (SEM), X-ray diffractometry (XRD) and calculations of theoretical
density and particle average diameter. The ceramics have been characterized by SEM and
XRD. The adequate characteristics of LSM have been evaluated aiming at the use in the
preparation of suspensions for cathodic thin films of SOFCs.
Synthesis of Alumina Powders by Mechanical Activation
Authors: Chinelatto Adriana Scoton Antonio , Lago C. , Antunes S.R.M. , Antunes A.C. , Cintho Osvaldo Mitsuyuki , Chinelatto Adilson Luiz
Published: March 2009

Alumina is utilized in many areas of modern industry because of its unique mechanical, electrical and optical properties. Various methods are been employed for produce alumina for different end uses. The preparation of fine and sintering-reactive alumina powders is probably one of the most important steps for production alumina ceramics with controlled microstructure. In this work, it was studied the production of alumina powders by “Pechini” method associated to highenergy milling. For this, it was prepared the resin by Pechini method, using aluminum nitrate nonahydrate. This resin was calcined at 500oC. Then, the calcined powders were submitted a high energy milling for different times. The powders mechanically activated were characterized by x ray diffraction, FT-IR and scanning electronic microscopic. After milling, the powders were calcined at 900oC. The results showed that the alumina phase transitions and powders characteristics were modified when the step of activation mechanical was introduced.
3YTZP-Al2O3 Powders Synthesized by the Coprecipitation Route
Authors: Garcia R.H.L. , Ussui Valter , de Lima Nelson Batista , Lazar Dolores Ribeiro Ricci
Published: March 2009

The addition of alumina in a zirconia stabilized in a tetragonal phase matrix
enhances ceramic hardness and inhibits the tetragonal → monoclinic phase transformation of
zirconia when exposed to an aqueous environment. These characteristics are important for
applications such as bioceramics and structural materials. For these purposes, the strict control
of powder synthesis and the processing conditions are vital to tailor the ceramic
characteristics. This work evaluates the influence of 20 wt% alumina in a Y-TZP matrix on
powder characteristics, obtained by coprecipitation route, and calcined from 600 to 1200°C
for 1 and 3 hours. The powders obtained were characterized by X-ray diffraction, scanning
electronic microscopy, laser diffraction and gaseous adsorption (BET). The results reveal that
presence of Al3+ inhibits the crystallization of composite at lower temperatures.
Physical Properties of Nylon 66/Organoclay Nanocomposites
Authors: Araújo Edcleide Maria , Araujo K.D. , de Gouveia Silva Taciana Regina
Published: March 2009

Nanocomposites containing nylon 66 and montmorillonite clay organically modified with quaternary ammonium salts were obtained via direct melt intercalation. A montmorillonite sample from Boa Vista/PB, Northeast of Brazil, was treated with three types of quaternary ammonium salts such as Genamin, Praepagen and Cetremide. After the treatment, the powder was characterized by X-ray diffraction (XRD). The produced nanocomposites were characterized by Torque Rheometer, Infrared Spectroscopy (FTIR), mechanical properties and HDT. The obtained results for rheological characterization showed that the nanocomposites did not present deterioration with the presence of modified clay. Generally, the mechanical properties of tensile of the systems presented superior values compared to that of pure Ny 66. HDT's properties presented very interesting values for the nanocomposites and significantly larger than for pure nylon 66.
Contribution to a Technological Characterization of Kaolins from Cuba and Brazil
Authors: Cortés Guillermo Ruperto Martín , Hennies Wildor Theodoro , Valenzuela-Díaz Francisco Rolando
Published: March 2009

This paper studies the main well-know technological types of kaolins clays from
the Republic of Cuba and compares it with one from Brazil. A simple description from the
Cuban geology and from the involved kaolins deposits is showed. The basic characterization
of each kind of kaolin, includes, chemical analyzes, grain size distribution, scanning
electronic microscopy, X-ray diffraction and X-ray fluorescence for chemicals. For special
assays it had conformed, by a simple axis hand press up to 5 t, test bodies, which had been
burnt to the temperatures of 950, 1250 and 1450°C. These results include refractory and
contraction results.
Research on Man-Machine Cooperation Manipulator and Information Integrated Technology in Advanced Manufacturing
Authors: Guo Qian Jian , Yang Jian Guo , Qi Xiao Ni , Wang Xiu Shan
Published: March 2009

Aimed at the requirement of a project, a man-machine cooperation(MMC) manipulator was designed based on its system structure and man-machine function analysis. Meanwhile, the system functions were allocated between man and manipulator, and in order to realize information integration in MMC material handling system, a application method of mechatronics was discussed. Then an example is given to express one of the realization methods of information communication between man and manipulator.
A Study on Multi-Colony Diploid Immune Algorithm and Its Application in Manufacture
Authors: Si Shu Bin , Sun Shu Dong , Hou Pei Yong , Yu Jian Jun
Published: March 2009

Manufacture cell scheduling (MCS) is a NP-hard problem, and the traditional optimization
methods have their limitations when dealing with MCS. Immune algorithm that simulates the
biologic immunity system is an intelligent optimization method and has potential to solve MCS.
Multi-colony diploid immune algorithm (MDIA) is put forward to solve MCS. Firstly, the model of
MCS is set up. Then, a typical benchmark problem is simulated with MDIA and other algorithms.
Finally, simulation results show that MDIA is both effective and superior to other algorithms.
A New Approach to the Communication of the Distributed Collaborative System Based on COM+
Authors: Huang Chang Biao , Jiang Kai Yong , Xu Xi Peng
Published: March 2009

In this paper COM+ based on Microsoft .NET is adopted to realize a Distributed
Collaborative System (DCS). This system adopts a complex architecture combined C/S with B/S to
reduce the remote communication and improve the performance. By means of IE or other browsers, a
client can download client tool, register or login, search or publish information via the collaborative
website. After installing the client tool, a client can automatically receive the collaborative requests or
invitations from the collaborative server and collaborate with other participators. The system utilizes
COM+ services to realize the Distributed Synchronous Communication (DSC) and Distributed
Asynchronous Communication (DAC). Loosely Coupled Event (LCE) service can make DSC true
easily and effectively. Transaction service, Queued Component (QC) service and Windows NT
Service can be applied to realize DAC efficiently and reliably.
Effect of Filler Shape and Volume Fraction on Strain Damage of Particulate-Reinforced Dental Composites
Authors: Chan Yiu Pong , Tang Chak Yin , Darvell Brian W. , Tsui Chi Pong
Published: March 2009

The effect of filler shape and volume fraction on the micromechanical damage behavior
of particulate-reinforced dental composites was investigated using the finite element method. Threedimensional
unit cell models for various filler volumes and shapes, using hydroxyapatite in Bis-
GMA as a model system, were used. Young’s modulus and stress concentration factor were
calculated. The effects of filler shape on the ease of initiation of strain damage in the matrix and
onset of particle-matrix debonding are discussed.